MOUNTING STAGE AND PLASMA PROCESSING APPARATUS

Abstract

A mounting stage for a plasma processing apparatus that can prevent degradation of an insulating film in a semiconductor device on a substrate. A conductor member is connected to a radio-frequency power source for producing plasma. A dielectric layer is buried in a central portion of an upper surface of the conductor member. An electrostatic chuck is mounted on the dielectric layer. The electrostatic chuck has an electrode film that satisfies the following condition: δ/z≧85 where δ=(ρv/(μπf))1/2 where z is the thickness of the electrode film, δ is the skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is the frequency of the radio-frequency electrical power, π is the ratio of a circumference of a circle to its diameter, μ is the magnetic permeability of the electrode film, and ρv is the specific resistance of the electrode film.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mounting stage on which a substrate subjected to plasma processing is mounted, and a plasma processing apparatus having the mounting stage, and in particular to a mounting stage in which a dielectric layer is buried.

2. Description of the Related Art

In a process of manufacturing a semiconductor device, a semiconductor wafer (hereinafter referred to merely as a “wafer”) is subjected to plasma processing such as dry etching or ashing using plasma produced from a process gas. In a plasma processing apparatus that carries out the plasma processing, for example, a pair of upper and lower parallel plate electrodes are disposed in a manner opposed to each other, and radio-frequency electrical power is applied between the opposing electrodes, whereby plasma is produced from a process gas. When the plasma processing is to be carried out, a wafer is mounted on the lower electrode as a mounting stage.

In recent years, there have been many cases where plasma with low ion energy and high electron density is used for the plasma processing, and accordingly, the frequency of radio-frequency electrical power applied between electrodes is very high, for example, 100 MHz, as compared with the frequency of conventionally applied radio-frequency electrical power (for example, about more than a dozen MHz). However, it has been found that if the frequency of radio-frequency electrical power to be applied is increased, the intensity of an electric field increases in a central portion of the surface of an electrode, that is, a space facing a central portion of a wafer, and on the other hand, the intensity of the electric field decreases in a space facing a peripheral edge portion of the surface of the electrode. Thus, if the distribution of the intensities of the electric field becomes nonuniform, the electron densities of produced plasma also become nonuniform. For this reason, the etching speed varies according to the position of a wafer in the case of, for example, dry etching using ions, and it is thus difficult to ensure the over-surface uniformity in the dry etching.

To cope with this, there has been proposed a plasma processing apparatus in which a dielectric layer such as ceramics is buried in a central portion of a surface facing a lower electrode (mounting stage) so as to make the intensity distribution of an electric field uniform and improve the over-surface uniformity in plasma processing (see, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2004-363552 (paragraphs 84 and 85 on page 15)).

As shown in FIG. 15A, in a plasma processing apparatus 140, when radio-frequency electrical power is supplied from a radio-frequency power source 142 to a lower electrode 141, the radio-frequency electrical current that passes through a surface of the lower electrode 141 to reach an upper portion of the lower electrode 141 due to a skin effect goes toward a central portion of a wafer W along a surface thereof, while a part of the radio-frequency electrical current leaks from the central portion of the surface of the wafer W toward the lower electrode 141 and then flows through the interior of the lower electrode 141 toward the outside. Here, in a part of the lower electrode 141 where a dielectric layer 143 is buried, the radio-frequency electrical current can fall down deeper than in other parts, and thus TM mode hollow cylindrical resonance occurs in the central portion of the lower electrode 141. As a result, the intensity of the electric field facing the central portion of the wafer W can be reduced, so that the intensity distribution of the electric field facing the wafer W can be made uniform.

Because plasma processing is carried out in a pressure-reduced atmosphere in many cases, an electrostatic chuck 144 is used so as to fix the wafer W in the plasma processing apparatus 140 as shown in FIG. 15B. In the electrostatic chuck 144, a conductive electrode film 145 is sandwiched between a lower member and an upper member made of dielectric materials such as alumina. In plasma processing, high-voltage DC power is supplied from a high-voltage DC power source 146 to the electrode film 145, so that the wafer W is electrostatically attracted and fixed due to a Coulomb force produced on a surface of the upper member of the electrostatic chuck 144.

While the component parts of the plasma processing apparatus 140 are thought to constitute an electric circuit associated with radio-frequency electrical current, the wafer W is also thought to be a constituent element of the electric circuit because the wafer W is comprised of a semiconductor such as silicon. When the wafer W is electrostatically attracted to the electrostatic chuck 144, the wafer W becomes parallel to the electrode film 145, and hence the wafer W and the electrode film 145 are thought to correspond to resistances disposed parallel in the electric circuit.

Therefore, the value of radio-frequency electric current flowing through the wafer W depends on the balance between the resistance value of the wafer W and the resistance value of the electrode film 145. For example, there has been the problem that if the resistance value of the electrode film 145 is extremely high, excessive radio-frequency electric current flows to the wafer W, and at this time, a gate oxide film in a semiconductor device on the wafer W degrades due to charge-up.

Also, if the resistance value of the electrode film 145 is extremely small, radio-frequency electric current that leaks from the central portion of the surface of the wafer W toward the lower electrode 141 tends to flow through the electrode film 145, and hence the radio-frequency electric current cannot fall down deep in the central portion of the surface of the wafer W. As a result, TM mode hollow cylindrical resonance cannot be produced, and thus the intensity distribution of the electric field becomes nonuniform, and the electron density of plasma becomes high in the space facing the central portion of the wafer W. For this reason, galvanic electric current flowing from the central portion to the peripheral edge portion of the wafer W is produced. At this time as well, the gate oxide film in the semiconductor device on the wafer W degrades due to charge-up.

In order to prevent the charge-up of the gate oxide film, it is necessary to limit the range of the resistance values of the electrode film 145, that is, it is necessary to manage the resistance value of the electrode film 145. In general, however, because the electrode film 145 of the electrostatic chuck 144 is sintered while being supported from both sides thereof between the lower member and the upper member, there has been the problem that in a process of manufacturing the electrostatic chuck 144 and after the electrostatic chuck 144 is manufactured, the resistance value of the electrode film 145 cannot be measured, and thus the resistance value of the electrode film 145 cannot be managed.

SUMMARY OF THE INVENTION

The present invention provides a mounting stage and a plasma processing apparatus that can prevent degradation of an insulating film in a semiconductor device on a substrate.

The present invention also provides a mounting stage and a plasma processing apparatus that can manage the resistance value of an included electrode film.

Accordingly, in a first aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following condition: δ/z≧85, where δ=(ρ_v/(μπf))^1/2 and where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, and ρ_v is a specific resistance of the electrode film.

According to the first aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition “δ/z≧85”. The skin depth δ is a thickness with which the intensity of an electric field decreases by 1/e in the electrode film. The greater the skin depth δ is, the easier it becomes for the electric field to pass through the electrode film, and hence the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep. Thus, if δ/z≧85, the major portion of radio-frequency electric current can pass through the electrode film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, and galvanic electric current can be prevented from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate and also makes it possible to carry out plasma processing uniformly over the surface of the substrate.

Accordingly, in a second aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following condition: ρ_s≦2.67×10⁵Ω/□, where ρ_s is a surface resistivity of the electrode film.

According to the second aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition “ρ_s≦2.67×10⁵Ω/□”. The smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow in the electrode film. Thus, if ρ_s≦2.67×10⁵Ω/□, excessive radio-frequency electric current can be prevented from flowing to the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a third aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following conditions: δ/z≧85 and ρ_s≦2.67×10⁵Ω/□, where δ=(ρ_v/μπf))^1/2 and where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, ρ_v is a specific resistance of the electrode film, and ρ_s is a surface resistivity of the electrode film.

According to the third aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition that “δ/z≧85” and the condition that “ρ_s≦2.67×10⁵Ω/□”. The greater the skin depth δ is, the easier it becomes for an electric field to pass through the electrode film, and hence the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep. Also, the smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow in the electrode film. Thus, if δ/z≧85 and ρ_s≦2.67×10⁵Ω/□, the major portion of radio frequency electronic current can pass through the electrode film in the direction of thickness and fall dawn deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate and preventing excessive radio-frequency electric current from flowing to the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a fourth aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following conditions: 115Ω/□≦ρ_s≦2.67×10⁵Ω/□, where ρ_s is a surface resistivity of the electrode film.

According to the fourth aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition “115Ω/□≦ρ_s≦2.67×10⁵Ω/□.” The greater the surface resistivity of the electrode film is, the harder it becomes for radio-frequency electric current to flow in the electrode film, and hence the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep, and also, the smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow to the electrode film. Thus, if 115Ω/□≦ρ_s≦2.67×10⁻⁵Ω/□, the major portion of radio-frequency electric current can pass through the electrode film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate and preventing excessive radio-frequency electric current from flowing to the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

The second aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the surface resistivity ρ_s is not more than 304Ω/□.

According to the second aspect of the present invention, it is possible to reliably prevent excessive radio-frequency electric current from flowing to the substrate.

The first aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the electrode film is formed by one of thermal spraying, sintering and coating, and the specific resistance of the electrode film is 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm.

According to the first aspect of the present invention, the electrode film that satisfies the condition that “δ/z≧85” and the condition that “ρ_s≦2.67×10⁵Ω/□” can be fabricated with ease.

The first aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the electrode film is formed by one of CVD, PVD, and liquid deposition, a thickness of the electrode film is not more than 10 μm, and the specific resistance of the electrode film is not more than 1.0×10² Ω·cm.

According to the first aspect of the present invention, the electrode film that satisfies the condition that “δ/z85” and the condition that “ρ_s≦2.67×10⁵Ω/□” can be fabricated with ease.

The first aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein a frequency of radio-frequency electrical power supplied from the radio-frequency power source for producing plasma is not less than 27 MHz.

According to the first aspect of the present invention, plasma with low ion energy and high electron density can be produced.

The second aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein a frequency of radio-frequency electrical power supplied from the radio-frequency power source for attracting ions is not more than 27 MHz.

According to the second aspect of the present invention, ions in plasma can be reliably attracted toward the substrate mounted on the mounting stage.

Accordingly, in a fifth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and the substrate satisfies the following condition: δ_w/z_w≧13, where δ_w=(ρ_vw/(μ_wπf))^1/2 and where z_w is a thickness of the substrate, δ_w is a skin depth of the substrate with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ_w is a magnetic permeability of the substrate, and ρ_vw is a specific resistance of the substrate.

According to the fifth aspect of the present invention, the substrate that satisfies the condition that “δ_w/z_w≧13” is mounted on the mounting stage. The skin depth δ_w of the substrate is a thickness with which the intensity of an electric field decreases by 1/e in the substrate. The greater the skin depth δ_w is, the easier it becomes for the electric field to pass through the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if δ_w/z_w≧13, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a sixth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and the substrate satisfies the following condition: ρ_sw≧52Ω/□, where ρ_sw is a surface resistivity of the substrate.

According to the sixth aspect of the present invention, the substrate that satisfies the condition that “ρ_sw≧52Ω/□” is mounted on the mounting stage. The greater the surface resistivity of the substrate is, the harder it becomes for radio-frequency electric current to flow in the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if ρ_sw≧52Ω/□, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a seventh aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and the substrate satisfies the following condition: ρ_vw≧4 Ω·cm, where ρ_vw is a specific resistance of the substrate.

According to the seventh aspect of the present invention, the substrate that satisfies the condition that “ρ_vw≧4 Ω·cm” is mounted on the mounting stage. The greater the specific resistance of the substrate is, the harder it becomes for radio-frequency electric current to flow in the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if ρ_vw≧4 Ω·cm, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of an electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in an eighth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and a wiring film on the substrate satisfies the following condition: δ₁/z₁>13, where δ₁=(ρ_v1/(μ₁πf))^1/2 and where z₁ is a thickness of the wiring film, δ₁ is a skin depth of the wiring film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ₁ is a magnetic permeability of the wiring film, and ρ_v1 is a specific resistance of the wiring film.

According to the eighth aspect of the present invention, the substrate having the wiring film that satisfies the condition that “δ₁/z₁≧13” is mounted on the mounting stage. The skin depth δ₁ of the wiring film on the substrate is a thickness with which the intensity of an electric field decreases by 1/e in the wiring film. The greater the skin depth δ₁ is, the easier it becomes for an electric field to pass through the wiring film, and hence the easier it becomes for radio-frequency electric current to pass through the wiring film in the direction of thickness and fall down deep. Thus, if δ₁/z₁≧13, the major portion of radio-frequency electric current can pass through the wiring film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the wiring film on the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the wiring film on the substrate can be made uniform, thus preventing galvanic electric current from being produced in the wiring film on the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a ninth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and a wiring film on the substrate satisfies the following condition: ρ_s1≧52Ω/□, where ρ_s1 is a surface resistivity of the wiring film.

According to the ninth aspect of the present invention, the substrate having the wiring film that satisfies the condition that “ρ_s1≧52Ω/□” is mounted on the mounting stage. The greater the surface resistivity of the wiring film on the substrate is, the harder it becomes for radio-frequency electric current to flow in the wiring film, and hence the easier it becomes for radio-frequency electric current to fall down deep. Thus, if ρ_s1≧52Ω/□, the major portion of radio-frequency electric current can pass through the wiring film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the wiring film on the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the wiring film on the substrate can be made uniform, thus preventing galvanic electric current from being produced in the wiring film on the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a tenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: δ/z≧=85, where δ=(ρ_v/(μπf))^1/2 and where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, and ρ_v is a specific resistance of the electrode film.

According to the tenth aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition that “δ/z≧85”. The skin depth δ is a thickness with which the intensity of an electric field decreases by 1/e in the electrode film. The greater the skin depth δ is, the easier it becomes for an electric field to pass through the electrode film, and the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep. Thus, if δ/z≧85, the major portion of radio-frequency electric current can pass through the electrode film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate and also makes it possible to carry out plasma processing uniformly over the surface of the substrate.

Accordingly, in an eleventh aspect of the present invention, there is provided A plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: ρ_s≦2.67×10⁵Ω/□, where μ_s is a surface resistivity of the electrode film.

According to the eleventh aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition that “ρ_s≦2.67×10⁵Ω/□”. The smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow in the electrode film. Thus, if ρ_s≦2.67×10⁵Ω/□, excessive radio-frequency electric current can be prevented from flowing in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a twelfth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following conditions: δ/z≧85 and ρ_s=2.67×10⁵Ω/□, where δ=(ρ_v/(μπf))^1/2 and where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, ρ_v is a specific resistance of the electrode film, and ρ_s is a surface resistivity of the electrode film.

According to the twelfth aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition “δ/z≧85” and the condition that “ρ_s≦2.67×10⁵Ω/□”. The greater the skin depth δ is, the easier it becomes for an electric field to pass through the electrode film, and hence the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep. Also, the smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow in the electrode film. Thus, if δ/z≧85 and ρ_s≦2.67×10⁵Ω/□, the major portion of radio-frequency electric current can pass through the electrode film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate and preventing excessive radio-frequency electric current from flowing in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a thirteenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: 115 Ω/□≦ρ_s≦2.67×10⁵Ω/□, where ρ_s is a surface resistivity of the electrode film.

According to the thirteenth aspect of the present invention, there is provided the electrostatic chuck having the electrode film that satisfies the condition “115 Ω/□≦ρ_s≦2.67×10⁵Ω/□”. The greater the surface resistivity of the electrode film is, the harder it becomes for radio-frequency electric current to flow in the electrode film, and hence the easier it becomes for radio-frequency electric current to pass through the electrode film in the direction of thickness and fall down deep. Also, the smaller the surface resistivity of the electrode film is, the easier it becomes for radio-frequency electric current to flow in the electrode film. Thus, if 115 Ω/□≦ρ_s≦2.67×10⁵Ω/□, the major portion of radio-frequency electric current can pass through the electrode film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the electrode film. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of an electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate and preventing excessive radio-frequency electric current from flowing in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a fourteenth aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and the electrode film is formed on an upper surface or a lower surface of a plate-shaped base material comprising a dielectric member prepared/formed in advance, and coated with an insulating material after the electrode film is formed.

According to the fourteenth aspect of the present invention, the electrode film included in the electrostatic chuck provided in the mounting stage exposes itself once without exception before being covered with an insulating material in a process of manufacturing the electrostatic chuck. This make it possible to measure the resistance value of the electrode film and thus manage the resistance value of the included electrode film in the process of manufacturing the electrostatic chuck.

The fourteenth aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the electrode film is formed by thermal spraying, coating, thin-film formation, and attachment of a conductive film.

According to the fourteenth aspect of the present invention, the electrode film can be reliably formed.

The fourteenth aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the thin-film formation is one of CVD, PVD, and liquid deposition.

According to the fourteenth aspect of the present invention, the electrode film can be reliably and easily formed of a thin film.

The fourteenth aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein the insulating material is formed by one of sintering, thermal spraying, and attachment of an insulating film.

According to the fourteenth aspect of the present invention, the insulating material film can be reliably formed.

Accordingly, in a fifteenth aspect of the present invention, there is provided a mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising a conductor member connected to a radio-frequency power source, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, wherein the electrostatic chuck is connected to a high-voltage direct current power source, includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and further has at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof being exposed from a surface of the electrostatic chuck.

According to the fifteenth aspect of the present invention, because the electrode film included in the electrostatic chuck provided in the mounting stage is communicated with the outside via the at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof being exposed from the surface of the electrostatic chuck, it is possible to measure the resistance value of the electrode film and thus manage the resistance value of the included electrode film after the electrostatic chuck is manufactured.

The fifteenth aspect of the present invention can provide a mounting stage for a plasma processing apparatus, wherein at least one of the two conductive members is disposed in a central portion of the electrostatic chuck.

According to the fifteenth aspect of the present invention, the resistance value of at least the central portion of the electrode film can be managed.

Accordingly, in a sixteenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-voltage direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and the electrode film is formed on an upper surface or a lower surface of a plate-shaped base material comprising a dielectric member prepared/formed in advance, and coated with an insulating material after the electrode film is formed.

According to the sixteenth aspect of the present invention, the electrode film included in the electrostatic chuck provided in the mounting stage exposes itself once without exception before being covered with an insulating material in a process of manufacturing the electrostatic chuck. This make it possible to measure the resistance value of the electrode film and thus manage the resistance value of the included electrode film in the process of manufacturing the electrostatic chuck.

Accordingly, in a seventeenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage on which a substrate is mounted, wherein the mounting stage comprises a conductor member connected to a radio-frequency power source, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer, the electrostatic chuck is connected to a high-power direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and further has at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof exposed from a surface of the electrostatic chuck.

According to the seventeenth aspect of the present invention, because the electrode film included in the electrostatic chuck provided in the mounting stage is communicated with the outside via the at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof being exposed from the surface of the electrostatic chuck, it is possible to measure the resistance value of the electrode film and thus manage the resistance value of the included electrode film after the electrostatic chuck is manufactured.

Accordingly, in an eighteenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage for the above plasma processing apparatus, wherein the substrate mounted on the mounting stage satisfies the following condition: δ_w/z_w≧13, where δ_w=(ρ_vw/(μ_wπf))^1/2 and where z_w is a thickness of the substrate, δ_w is a skin depth of the substrate with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ_w is a magnetic permeability of the substrate, and ρ_vw is a specific resistance of the substrate.

According to the eighteenth aspect of the present invention, the substrate that satisfies the condition that “δ_w/z_w≧13” is mounted on the mounting stage. The skin depth δ_w of the substrate is a thickness with which the intensity of an electric field decreases by 1/e in the substrate. The greater the skin depth δ_w is, the easier it becomes for an electric field to pass through the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if δ_w/z_w≧13, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in an nineteenth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage for the above plasma processing apparatus, wherein the substrate mounted on the mounting stage satisfies the following condition: ρ_sw≧52Ω/□, where ρ_sw is a surface resistivity of the substrate.

According to the nineteenth aspect of the present invention, the substrate that satisfies the condition that “ρ_sw≧52Ω/□” is mounted on the mounting stage. The greater the surface resistivity of the substrate is, the harder it becomes for radio-frequency electric current to flow in the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if ρ_sw≧52Ω/□, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of an electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in an twelfth aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage for the above plasma processing apparatus, wherein the substrate mounted on the mounting stage satisfies the following condition: ρ_vw≧4 Ω·cm, where ρ_vw is a specific resistance of the substrate.

According to the twelfth aspect of the present invention, the substrate that satisfies the condition that “ρ_vw≧4 Ω·cm” is mounted on the mounting stage. The greater the specific resistance of the substrate is, the harder it becomes for radio-frequency electric current to flow in the substrate, and hence the easier it becomes for radio-frequency electric current to pass through the substrate in the direction of thickness and fall down deep. Thus, if ρ_vw≧4 Ω·cm, the major portion of radio-frequency electric current can pass through the substrate in the direction of thickness and fall down deep toward the dielectric layer without flowing in the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of an electric field in a space facing the substrate can be made uniform, thus preventing galvanic electric current from being produced in the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a twenty-first aspect of the present invention, there is provided a plasma processing apparatus comprising a mounting stage for the above plasma processing apparatus, wherein a wiring film on the substrate mounted on the mounting stage satisfies the following condition: δ₁/z₁≧13, where δ₁=(ρ_v1/(μ₁πf))^1/2 and where z₁ is a thickness of the wiring film, δ₁ is a skin depth of the wiring film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the wiring film, and ρ_v1 is a specific resistance of the wiring film.

According to the twenty-first aspect of the present invention, the substrate having the wiring film that satisfies the condition that “δ₁/z₁≧13” is mounted on the mounting stage. The skin depth δ₁ of the wiring film on the substrate is a thickness with which the intensity of an electric field decreases by 1/e in the wiring film. The greater the skin depth δ₁ is, the easier it becomes for an electric field to pass through the wiring film, and hence the easier it becomes for radio-frequency electric current to pass through the wiring film in the direction of thickness and fall down deep. Thus, if δ₁/z₁≧13, the major portion of radio-frequency electric current can pass through the wiring film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the wiring film on the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of the electric field in a space facing the wiring film on the substrate can be made uniform, thus preventing galvanic electric current from being produced in the wiring film on the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

Accordingly, in a twenty-second aspect of the present invention, there is provided a plasma processing apparatus comprising: a mounting stage for the above plasma processing apparatus, wherein a wiring film on the substrate mounted on the mounting stage satisfies the following condition: ρ_s1≧52Ω/□, where ρ_s1 is a surface resistivity of the wiring film.

According to the twenty-second aspect of the present invention, the substrate having the wiring film that satisfies the condition that “ρ_s1≧52Ω/□” is mounted on the mounting stage. The greater the surface resistivity of the wiring film on the substrate is, the harder it becomes for radio-frequency electric current to pass through the wiring film, and hence the easier it becomes for radio-frequency electric current to fall down deep. Thus, if ρ_s1≧52Ω/□, the major portion of radio-frequency electric current can pass through the wiring film in the direction of thickness and fall down deep toward the dielectric layer without flowing in the wiring film on the substrate. As a result, TM mode hollow cylindrical resonance is produced, so that the distribution of intensities of an electric field in a space facing the wiring film on the substrate can be made uniform, thus preventing galvanic electric current from being produced in the wiring film on the substrate. This prevents degradation of an insulating film in a semiconductor device on the substrate.

The features and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view schematically showing the construction of a plasma processing apparatus having a mounting stage according to an embodiment of the present invention;

FIGS. 2A and 2B are views useful in explaining the case that high-output radio-frequency electrical power is supplied from a first radio-frequency power source in the plasma processing apparatus in FIG. 1, in which FIG. 2A is a partial cross-sectional view schematically showing the construction of an electrostatic chuck and its vicinity, and FIG. 2B is a view showing an electrical circuit comprised of the first radio-frequency power source and others;

FIGS. 3A and 3B are views useful in explaining the case that high-output radio-frequency electrical power is supplied from a second radio-frequency power source in the plasma processing apparatus in FIG. 1, in which FIG. 3A is a partial cross-sectional view schematically showing the construction of an electrostatic chuck and its vicinity, and FIG. 3B is a view showing an electrical circuit comprised of the second radio-frequency power source and others;

FIG. 4 is a graph showing the distribution of etching speeds at which photoresists over surfaces of respective wafers are etched in the case that a plurality of electrode films having different values of δ/z;

FIG. 5 is a table showing the degrees to which gate oxide films in TEGs of respective test wafers are degraded in the case that a plurality of electrode films having different values of δ/z are used;

FIG. 6 is a graph showing the relationship between the thickness of an electrode film, which is intended to prevent the degradation of a gate oxide film in a device having a normal antenna ratio, and the specific resistance of the electrode film;

FIG. 7 is a graph showing the other relationship between the thickness of an electrode film, which is intended to prevent the degradation of a gate oxide film of a device having a normal antenna ratio, and the specific resistance of the electrode film;

FIG. 8 is a graph showing the relationship between the thickness of an electrode film, which is intended to prevent the degradation of a gate oxide film in a specialized device, and the specific resistance of the electrode film;

FIG. 9 is a graph showing the distribution of etching speeds at which surfaces of a plurality of test wafers are etched in the case that the plurality of test wafers have different specific resistance values are used;

FIG. 10 is an enlarged cross-sectional view schematically showing the construction of the electrostatic chuck in FIG. 1 and its vicinity;

FIGS. 11A and 11B are enlarged cross-sectional views schematically showing the constructions of variations of the electrostatic chuck in FIG. 1, in which FIG. 11A shows a first variation, and FIG. 11B shows a second variation;

FIGS. 12A and 12B are enlarged cross-sectional views schematically showing the construction of a third variation of the electrostatic chuck in FIG. 1, in which FIG. 12A is a cross-sectional view, and FIG. 12B is an enlarged view of a part A in FIG. 12A;

FIG. 13 is a plan view showing a variation of an electrode film in FIG. 10;

FIGS. 14A and 14B are views schematically showing the construction of a fourth variation of the electrostatic chuck in FIG. 1, in which FIG. 14A is a rear view, and FIG. 14B is a cross-sectional view; and

FIGS. 15A and 15B are cross-sectional views schematically showing the construction of a plasma processing apparatus that can improve the over-surface uniformity of conventional plasma processing, in which FIG. 15A shows the case that there is provided no electrostatic chuck, and FIG. 15B shows the case that there is provided an electrostatic chuck.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the drawings showing a preferred embodiment thereof.

FIG. 1 is a cross-sectional view schematically showing the construction of a plasma processing apparatus having a mounting stage according to the present embodiment. The plasma processing apparatus is constructed such as to carry out plasma etching, for example, RIE (reactive ion etching) or ashing, on a semiconductor wafer (substrate) having a diameter of, for example, 300 mm.

Referring to FIG. 1, the plasma processing apparatus 10 has a processing container 11 comprised of, for example, a vacuum chamber, a mounting stage 12 that is disposed in a central portion of a bottom of the processing container 11, and an upper electrode 13 that is provided above the mounting stage 12 such as to face the mounting stage 12.

The processing container 11 has a cylindrical upper chamber 11a having a small diameter, and a cylindrical lower chamber 11b having a large diameter. The upper chamber 11a and the lower chamber 11b communicate with each other, and the entire processing container 11 is constructed such as to be airtight. The mounting stage 12 and the upper electrode 13 are accommodated in the upper chamber 11a, and a supporting case 14 that supports the mounting stage 12 and in which piping for a cooling medium and a backside gas is stored are accommodated in the lower chamber 11b.

An exhaust port 15 is provided in a bottom of the lower chamber 11b, and an exhaust unit 17 is connected to the exhaust port 15 via an exhaust pipe 16. The exhaust unit 17 has an APC (adaptive pressure control) valve, a DP (dry pump), a TMP (turbo-molecular pump), and so on, all of which are not shown, and the APC valve and so on are controlled in accordance with signals from a controller, not shown, to evacuate and maintain the whole interior of the processing container 11 in a desired vacuum state. On the other hand, a transfer port 18 for wafers W is provided in a side face of the upper chamber 11a, and the transfer port 18 can be opened and closed by a gate valve 19. The upper chamber 11a and the lower chamber 11b are made of conductive members such as aluminum and grounded.

The mounting stage 12 has a lower electrode 20 (conductive member) for producing plasma, which is a stage-shaped member made of, for example, aluminum as a conductive material, a dielectric layer 21 that is made of, for example, ceramics as a dielectric material and buried in a central portion of an upper surface of the lower electrode 20 so as to make the intensity of an electric field uniform in a processing space, described later, and an electrostatic chuck 22 for electrostatically attracting and fixing a wafer W on a mounting surface. The lower electrode 20, dielectric layer 21, and electrostatic chuck 22 are laminated in this order in the mounting stage 12. Also, the lower electrode 20 is fixed on a supporting stage 23, which is installed on the supporting case 14, via an insulating member 24, and is electrically levitated relative to the processing container 11 to a sufficient degree.

A coolant flow path 25 through which a coolant is circulated is formed in the lower electrode 20. The coolant flowing through the coolant flow path 25 cools the lower electrode 20, and the wafer W mounted on the mounting surface of the upper surface of the electrostatic chuck 22 is cooled to a desired temperature.

The electrostatic chuck 22 is made of a dielectric material and includes a conductive electrode film 37. The electrode film 37 is made of, for example, an electrode material in which molybdenum carbide (MoC) is contained in alumina (Al₂O₃). A high-voltage DC power source 42 is connected to the electrode film 37, and high-voltage DC power supplied to the electrode film 37 generates a Coulomb force between the mounting surface of the electrostatic chuck 22 and the wafer W, so that the wafer W is attracted to and fixed on the mounting surface of the electrostatic chuck 22.

through holes 26 for emitting a backside gas for improving heat transference between the mounting surface of the electrostatic chuck 22 and a rear surface of the wafer W are opened to the electrostatic chuck 22. The through holes 26 communicate with a gas flow path 27 formed in the lower electrode 20 and so on, and the backside gas such as helium (He) supplied from a gas supply unit, not shown, is emitted through the gas flow path 27.

A first radio-frequency power source 28 (a radio-frequency power source for producing plasma) that supplies radio-frequency electrical power with, for example, a frequency of 27 MHz or higher and a second radio-frequency power source 29 (a radio-frequency power source for attracting ions) that supplies radio-frequency electrical power with a lower frequency than the frequency of the radio-frequency electrical power supplied from the first radio-frequency power source 28, for example, a frequency of 27 MHz or lower are connected to the lower electrode 20 via respective matchers 30 and 31. The radio-frequency electrical power supplied from the first radio-frequency power source 28 produces plasma from a process gas, described later, and the radio-frequency electrical power supplied from the second radio-frequency power source 29 supplies bias electrical power to the wafer W, so that ions in the plasma are attracted to the surface of the wafer W.

A focus ring 32 is disposed at an outer edge of an upper surface of the lower electrode 20 so as to surround the electrostatic chuck 22. The focus ring 32 spreads the plasma wider than a space facing the wafer W in the processing space, described later, so as to improve the uniformity of the etching speed over the surface of the wafer W.

A baffle plate 33 is provided on an outer side of a lower portion of the supporting stage 23 so as to surround the supporting stage 23. The baffle plate 33 circulates the process gas in the upper chamber 11a to the lower chamber 11b via a gap formed between the baffle plate 33 and a wall of the upper chamber 11a, thus playing a role as a rectifying plate and preventing the plasma in the processing space, described later, from leaking into the lower chamber 11b.

The upper electrode 13 has a ceiling electrode plate 34 made of a conductive material facing the interior of the upper chamber 11a, an electrode plate support 35 from which the ceiling electrode plate 34 is suspended, and a buffer chamber 36 provided in the electrode plate support 35. One end of a gas introducing pipe 38 is connected to the buffer chamber 36, and the other end of the gas introducing pipe 38 is connected to a process gas supply source 39. The process gas supply source 39 has a process gas supply amount control mechanism, not shown, and controls the amount of process gas to be supplied. A number of gas supply holes 40 that penetrate the ceiling electrode plate 34 and communicate the buffer chamber 36 and the interior of the upper chamber 11a together are formed in the ceiling electrode plate 34.

In the upper electrode 13, the process gas supplied from the process gas supply source 39 to the buffer chamber 36 is dispersed into the upper chamber 11a via the gas supply holes 40, and the upper electrode 13 thus acts as a showerhead supplying the process gas. Moreover, the upper electrode 13 is fixed to a wall of the upper chamber 13, and an electrically-conducting path is thus formed between the upper electrode 13 and the processing container 11.

In the plasma processing apparatus 10, two multi-pole ring magnets 41a and 41b are disposed around the upper chamber 11a and above and below the gate valve 19. In each of the multi-pole ring magnets 41a and 41b, a plurality of anisotropic segment columnar magnets, not shown, are accommodated in a ring-shaped magnetic casing, not shown, and they are arranged in the casing such that the direction of magnetic poles of the adjacent plurality of segment columnar magnets are opposite. Thus, a magnetic line is formed between the adjacent segment columnar magnets, a magnetic field is formed around the processing space located between the upper electrode 13 and the lower electrode 20, and the plasma is trapped in the processing space by the magnetic field. It should be noted that the plasma processing apparatus 10 may not be provided with the multi-pole ring magnets 41a and 41b.

In the plasma processing apparatus 10, when the wafer W is to be subjected to the RIE or the ashing, the pressure in the processing container 11 is adjusted to a desired vacuum state, and then a process gas is introduced into the upper chamber 11a to supply radio-frequency electrical power from the first radio-frequency power source 28 and the second radio-frequency power source 29, whereby the process gas is turned into plasma, and ions in the plasma are attracted to the wafer W. At this time, in order to produce plasma with low ion energy and high electron density, it is preferred that the first radio-frequency power source 28 supplies radio-frequency electrical power with a frequency of 27 MHz or higher, more preferably, 40 MHz or higher, and further, in order to reliably attract the ions in the plasma toward the wafer W, it is preferred that the second radio-frequency power source 29 supplies radio-frequency electrical power with a frequency of 27 MHz or lower, more preferably, 13.56 MHz or lower. The radio-frequency electrical power supplied from the first radio-frequency power source 28 and the second radio-frequency power source 29 flows through a path consisting of the lower electrode 20, the plasma, the upper electrode 13, a wall of the processing chamber 11, and a ground.

In the plasma processing apparatus 10, because the radio-frequency electrical power supplied from the first radio-frequency power source 28 has a relatively high frequency (40 MHz or higher), the intensity of the electric field in an area facing a central portion of the wafer W tends to be high in the processing space. In order to eliminate this tendency and make the intensity distribution of the electric field in the processing space uniform, the plasma processing apparatus 10 is provided with the dielectric layer 21 of the lower electrode 20. Due to the presence of the dielectric layer 21, the radio-frequency electrical power supplied from the first radio-frequency power source 28 falls down deep from the central portion of the wafer W toward the dielectric layer 21 of the lower electrode 20. As a result, TM mode hollow cylindrical resonance occurs in the central portion of the lower electrode 20, so that the intensity distribution of the electric field in the processing space is made uniform.

In the plasma processing apparatus 10, the first radio-frequency power source 28, second radio-frequency power source 29, dielectric layer 21, electrostatic chuck 22, electrode film 37, wafer W, plasma PZ, and so on (FIG. 2A) constitute an electric circuit 43 as shown in FIG. 2B. The second radio-frequency power source 29 and so on (FIG. 3A) constitute an electric circuit 44 as shown in FIG. 3B. Because the dielectric layer 21 exists only in the central portion of the lower electrode 20, a circuit 43a (44a) corresponding to the central portion of the lower electrode 20 and a circuit 43b (44b) corresponding to a peripheral edge portion of the lower electrode 20 are thought to exist in the electric circuit 43 (44), and the circuit 43a (44a) and the circuit 43b (44b) are bridged by a resistance R_W of the wafer W and a resistance R_E of the electrode film 37. When the wafer W is mounted on the mounting surface of the electrostatic chuck 22, the wafer W and the electrode film 37 become parallel with each other, and hence the resistance R_W of the wafer W and the resistance R_E are arranged parallel in terms of an electric circuit.

If the resistance R_E of the electrode film 37 is small in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, radio-frequency electrical current from the first radio-frequency power source 28 passes through the electrostatic chuck 22 in the direction of thickness from the central portion of the wafer W and further flows from the central portion of the electrostatic chuck 22 to the peripheral edge portion thereof through the electrode film 37 instead of falling down toward the dielectric layer 21. As a result, it becomes difficult to produce an electric field resulting from radio-frequency electrical current falling down to the dielectric layer 21 and passing through the electrode film 37. A description will now be given of this phenomenon.

In the present embodiment, a skin depth δ of the electrode film 37 is used as an index indicative of the degree to which the electric field passing through the electrode film 37 decreases. The skin depth δ is a thickness with which the intensity of the electric field passing through the electrode film 37 decreases by 1/e. If the skin depth δ is large, the electric field resists decreasing, and the electric field is apt to pass through the electrode film 37 well, and if the skin depth δ is small, the electric field is apt to decrease and resists passing through the electrode film 37. The skin depth δ is expressed by the following equation (1):

δ=(2ρ_v/(μω))^1/2=(ρ_v/(μπf))^1/2   (1)

where μ is a magnetic permeability (H/m) of the electrode film 37, ω is 2 πf (π: the ratio of the circumference of a circle to its diameter, and f: the frequency (Hz) of radio-frequency electrical power supplied from the first radio-frequency power source 28), and ρ_v is a specific resistance (Ω·m) of an electrode material constituting the electrode film 37.

The electric field E formed in the electrode film 37 is expressed by the following equation (2) using a Maxwell equation:

E=E₀ exp(−iωt)exp(iz/δ)exp(−z/δ)   (2)

where z is a thickness (m) of the electrode film 37, and E₀ is an intensity of the electric field incidents on the electrode film 37.

That is, the permeability (E/E₀) at which the electric field of the radio-frequency electrical power supplied from the first radio-frequency power source 28 passes through the electrode film 37 is proportional to “exp(−z/δ)” as expressed by the following equation (3):

E/E₀∝exp(−z/δ)   (3)

As is obvious from the above equation (3), the closer to “0” the value of “z/δ” becomes, the closer to 1.0 (100%) the permeability of the electric field becomes, and the smaller is “δ,” the smaller is the permeability of the electric field. Here, a low resistance R_E of the electrode film 37 is nothing else a low specific resistance ρ_v of the electrode film 37, and hence if the resistance R_E is small, the skin depth δ expressed by “ρ_v/(μπf))^1/2” is small, and it is thus difficult to produce the electric field passing through the electrode film 37.

If the electric field passing through the electrode film 37 is hardly produced, TM mode hollow cylindrical resonance does not occur in the central portion of the lower electrode 20, and the intensity of the electric field in an area facing the central portion of the wafer W (hereinafter referred to as the “central space”) in the processing space becomes higher than the intensity of the electric field in an area facing the peripheral edge of the wafer W (hereinafter referred to as the “peripheral edge space”) in the processing space, and the electron density of the plasma in the central space increases. As a result, the distribution of etching speeds over the surface of the wafer W becomes non-uniform.

Moreover, at this time, galvanic electric current (indicated by a dashed arrow in FIG. 2B) is produced in a circuit comprised of a resistance R_C of the plasma PZ, a sheath capacitor C_P of the plasma PZ, a capacitor C_T of a gate oxide film, and a resistance R_W of the wafer W in the electric circuit 43 due to the non-uniform distribution of electron densities of the plasma in the processing space. When the galvanic electric current flows in the wafer W, a gate oxide film (insulating film) in a semiconductor device (hereinafter referred to merely as a “device”) on the wafer W is damaged and degraded due to charge-up.

To make the distribution of etching speeds over the surface of the wafer W uniform and prevent degradation of the gate oxide film in the device in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, radio-frequency electric current from the first radio-frequency power source 28 has to be prevented from flowing through the electrode film 37, and the radio-frequency electrical current has to be caused to fall down deep toward the dielectric layer 21 so as to produce an electric field passing through the electrode film 37. To this end, “δ/z” has to be greater than in the above equation (3). To increase “δ/z”, it is only necessary to increase the skin depth δ or decrease the thickness “z” of the electrode film 37. Because the skin depth δ is expressed by “(ρ_v/(μπf))^1/2” as described above, it is only necessary to use an electrode material with a high specific resistance ρ_vto increase the resistance R_E of the electrode film 37 in the case that the frequency of the radio-frequency electrical power is constant. The higher the frequency of radio-frequency electrical power, the smaller the skin depth δ (δ∝(1/ω))=(1/2πf)), and hence if the frequency of radio-frequency electrical power is high, it is only necessary to use an electrode material with a higher specific resistance ρ_v as a constituent material of the electrode film 37.

Moreover, in the electric circuit 44, when high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29, because the capacitor C_T of the dielectric layer 21 exists in the circuit 44a corresponding to the central portion of the lower electrode 20, the radio-frequency electrical current from the second radio-frequency power source 29 mainly flows through the circuit 44b corresponding to the peripheral edge portion of the lower electrode 20, not through the circuit 44a, and in the end, flows back to the circuit 44a (indicated by a thick solid arrow in FIG. 3B). Here, if the resistance R_E of the electrode film 37 is set to be high, the resistance R_E of the electrode film 37 is higher than the resistance R_W of the wafer W, and hence the radio-frequency electrical current flowing back to the circuit 44a flows mainly through the wafer W, not through the electrode film 37. Thus, a potential difference arises in the surface of the wafer W, and the charge of the gate oxide film (insulating film) over the surface of the wafer W becomes unbalanced. As a result, the gate oxide film in the device on the wafer W is damaged and degraded due to charge-up.

To prevent the degradation of the gate oxide film in the device in the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29, it is necessary to prevent radio-frequency electric current from the second radio-frequency power source 29 from flowing mainly through the wafer W. To that end, it is only necessary to make the resistance R_E of the electrode film 37 small so that the radio-frequency electrical current can flow through the electrode film 37.

For the reasons stated above, to make the distribution of etching speeds over the surface of the wafer W uniform in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, it is only necessary to make the value of δ/z larger than a certain value (in other words, it is only necessary to make the resistance R_E of the electrode film 37 larger than a certain value). Moreover, to prevent the degradation of the gate oxide film in the device in both the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28 and the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29, it is only necessary to make the value of “δ/z” larger than a certain value and smaller than another certain value (in other words, it is only necessary to make the resistance R_E of the electrode film 37 larger than a certain value and make the resistance R_E of the electrode film 37 smaller than another certain value).

First, the inventors of the present invention prepared a plurality of electrode films 37 having different values of δ/z (and resistance R_E) so as to find a value of δ/z (and resistance R_E) that can make the distribution of etching speeds over the surface of the wafer W uniform. The inventors of the present invention then carried out the ashing on photoresists of wafers W using the respective electrode films 37 in the plasma processing apparatus 10, observed the distribution of etching speeds for the photoresists over the surfaces of the respective wafers W, and graphed the observation results in FIG. 4. As stated below, to remove the effect of the thickness of the electrode film 37 from the resistance R_E of the electrode film 37, the resistance value of the electrode film 37 was expressed by a surface resistivity ρ_s. The surface resistivity ρ_s is expressed by the following equation (4), and is a value indicative of a resistance value per unit area and determined by the property value (specific resistance ρ_v) of an electrode material constituting the electrode film 37 and the thickness of the electrode film 37:

ρ_s=ρ_v/z (Ω/□)   (4)

The values of δ/z (and ρ_s) of the electrode films 37 used here were 7518 (and 8.9×10⁵Ω/□), 6711 (and 2.67×10⁵Ω/□), 297 (and 1740Ω/□), 195 (and 750Ω/□), 124 (and 304Ω/□), 103 (and 208Ω/□), 92 (and 166Ω/□), 85 (and 115Ω/□), and 47 (and 35Ω/□).

Moreover, in the ashing, an O₂ single gas was introduced as a process gas into the upper chamber 11a at a flow rate of 100 sccm, the frequency of radio-frequency electrical power supplied from the first radio-frequency power source 28 was set to 100 MHz, and the value thereof was set to 2000 W, but no radio-frequency electrical power was supplied from the second radio-frequency power source 29.

In the graph of FIG. 4, the abscissa indicates the distance from the center of the wafer W, and the ordinate indicates the etching speed (nm/sec). The broken line corresponds to the case that δ/z (and the surface resistivity)=47 (35Ω/□), and the other solid line corresponds to the case that δ/z (and the surface resistivity)≧85 (115Ω/□).

From the graph of FIG. 4, it was found that if δ/z is not less than 85 (ρ_s is not less than 115Ω/□), the distribution of etching speeds over the surface of the wafer W can be made substantially uniform.

Next, the inventors of the present invention prepared a plurality of electrode films 37 having different values of δ/z (and resistance R_E) so as to find δ/z (and resistance R_E) that can prevent the degradation of a gate oxide film in both the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28 and the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29. Then, the inventors of the present invention carried out the RIE or the ashing on test wafers using the respective electrode films 37 in the plasma processing apparatus 10, observed the degradation of gate oxide films in TEGs (Test Element Groups) of the test wafers, and graphed the observation results in a table of FIG. 5.

In general, in the TEGs, the antenna ratio is set to 10 times or less, and to the maximum, 100 times or less, but here, to accelerate the degradation of the gate oxide films in the TEGs, test wafers whose antenna ratio in TEGs was set to 10000 (10 K) times, and test wafers whose antenna ratio in TEGs was set to 100000 (100 K) times (hereinafter referred to as the “100 K test wafers”) were used. As an index of the degradation of gate oxide films, the rate of the number of gate oxide films whose degradation levels did not exceed a predetermined value before and after the RIE or the ashing to the number of all the gate oxide films of the test wafers (hereinafter referred to as the “gate oxide survival rate (%)”) was used.

With respect to a threshold value for the gate oxide survival rate, in a normal plasma processing apparatus whose lower electrode 20 does not have the dielectric layer 21 and uses radio-frequency electrical power with a relatively low frequency for producing plasma, the gate oxide film survival rate was 54% when the RIE was carried out on the above-mentioned 100 K test wafers, and thus a percentage of 54% was used as a threshold value for the normal gate oxide film survival rate (hereinafter referred to as the “normal threshold value”). It should be noted that in the above-mentioned normal plasma processing apparatus, even when a test wafer having TEGs with a normal antenna ratio (about 10 times) was subjected to the RIE, degradation of a gate oxide film of the test wafer did not occur. Moreover, when a yield required when a specialized device is subjected to the RIE or the ashing is converted into the gate oxide survival rate when the above-mentioned 100 K test wafer is subjected to the RIE or the ashing, the yield corresponds to 65%, and thus the value of 65% was used as a threshold value for the gate oxide film survival rate in a specialized device when the 100 K test wafer was subjected to the RIE.

Moreover, δ/z (and ρ_s) of each electrode film 37 used here was set to be the same as δ/z (and ρ_s) when the above described distribution of etching speeds for a photoresist over the surface of each wafer was observed.

In the case that high-output radio-frequency electrical power was supplied from the first radio-frequency power source 28, an O₂ single gas was introduced as a process gas into the upper chamber 11a at a flow rate of 200 sccm, the frequency of the radio-frequency electrical power supplied from the first radio-frequency power source 28 was set to 100 MHz, the value thereof was set to 2400 W, and the ashing was carried out on each test wafer without supplying radio-frequency electrical power from the second radio-frequency power source 29. Further, in the case that high-output radio-frequency electrical power was supplied from the second radio-frequency power source 29, a mixed gas of C₄F₈ gas, Ar gas, and O₂ gas (the flow ratio: C₄F₈ gas/Ar gas/O₂ gas=35/200/30 sccm) was introduced as a process gas into the upper chamber 11a, the frequency of the radio-frequency electrical power supplied from the first radio-frequency power source 28 was set to 100 MHz, the value thereof was set to 500 W, the frequency of the radio-frequency electrical power supplied from the second radio-frequency power source 29 was set to 3.2 MHz, the value thereof was set to 4000 W, and the RIE was carried out on each test wafer. It should be noted that in FIG. 5, “high-power HF” corresponds to the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, and “high-power LF” corresponds to the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29.

The table of FIG. 5 shows plan views of test wafers which indicate in dark and light patterns the distributions of gate oxide films whose degradation levels did not exceed a predetermined value, and gate oxide film survival rates under respective test conditions. The dark-color parts in the distributions of gate oxide films correspond to gate oxide films whose degradation levels exceeded the predetermined value.

From the table of FIG. 5, it was found that in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, if δ/z is not less than 85 (ρ_s is not less than 115Ω/□), the gate oxide film survival rate when the 100 K test wafer is subjected to the ashing is not less than the normal threshold value (54%), and in the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29, if ρ_s is not more than 2.67×10⁵Ω/□, the gate oxide film survival rate when the 100 K test wafer is subjected to the RIE is not less than the normal threshold value (54%). It was thus found that if the conditions that “δ/z≧85 and ρ_s≦2.67×10⁵Ω/□” or the conditions that “115 Ω/□≦ρ_s≦2.67×10⁵Ω/□” are satisfied, the degradation of a gate oxide film in a device having the normal antenna ratio can be prevented in both the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28 and the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29.

Moreover, from the table of FIG. 5, it was found that in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, if δ/z is not less than 85 (ρ_s is not less than 115Ω/□), the gate oxide film survival rate when the 100 K test wafer is subjected to the ashing is not less than the specialized device threshold value (65%), and in the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29, if ρ_s is not more than 304Ω/□, the gate oxide film survival rate when the 100 K test wafer is subjected to the RIE is not less than the specialized device threshold value (65%). It was thus found that if the conditions that “δ/z≧85 and ρ_s≦304 Ω/□” or the conditions that “115Ω/□≦ρ_s≦304Ω/□” are satisfied, the degradation of a gate oxide film in a specialized device can be prevented in both the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28 and the case that high-output radio-frequency electrical power is supplied from the second radio-frequency power source 29.

The present invention has been developed based on the above-described findings, and according to the present embodiment, in the mounting stage 12 of the plasma processing apparatus 10, the skin depth δ of the electrode film 37 and the thickness thereof are set so as to satisfy the condition that “δ/z≧85”, and the surface resistivity ρ_s of the electrode film 37 is set so as to satisfy the condition that “ρ_s≦2.67×10⁵Ω/□”. Alternatively, the surface resistivity ρ_s of the electrode film 37 is set so as to satisfy the condition that “115Ω/□≦ρ_s≦2.67×10⁵Ω/□”.

The mounting stage 12 according to the present embodiment is provided with the electrostatic chuck 22 having the electrode film 37 that satisfies the condition “δ/z≧85” and the condition that “ρ_s≦2.67×10⁵Ω/□”. The greater the skin depth δ is, the easier it becomes for the electric field to pass through the electrode film 37. For this reason, high-output radio-frequency electric current from the first radio-frequency power source 28 can easily pass through the electrode film 37 in the direction of thickness and fall down deep toward the dielectric layer 21, and moreover, the smaller the surface resistivity ρ_s of the electrode film 37 is, the easier it becomes for radio-frequency electric current from the second radio-frequency power source 29 to flow in the electrode film 37. Therefore, if the electrode film 37 satisfies the conditions that δ/z≧85 and ρ_s≦2.67×10⁵Ω/□, the major portion of radio-frequency electric current can pass through the electrode film 37 in the direction of thickness and fall down deep toward the dielectric layer 21 without flowing in the electrode film 37. As a result, TM mode hollow cylindrical resonance is produced in the central portion of the lower electrode 20, so that the distribution of intensities of the electric field in the processing space can be made uniform, thus preventing galvanic electric current from being produced in a wafer W and preventing excessive radio-frequency electric current from flowing in a wafer W from the second radio-frequency electrical power 20. This prevents degradation of a gate oxide film in a device having a normal antenna ratio on a wafer W.

Moreover, according to the mounting stage 12 of the present embodiment, the electrode film 37 satisfies the condition that “115Ω/□≦ρ_s.” The higher the surface resistivity ρ_s of the electrode film 37, it becomes more difficult for radio-frequency electric current to flow in the electrode film 37, and hence radio-frequency electric current from the first radio-frequency power source 28 can pass through the electrode film 37 in the direction of thickness and fall down deep. Thus, if the electrode film 37 satisfies the condition that “115Ω/□≦ρ_s”, the major portion of radio-frequency electric current from the first radio-frequency power source 28 can pass through the electrode film 37 in the direction of thickness and fall down deep toward the dielectric layer 21.

In the mounting stage 12 described above, the electrode film 37 may be configured such as to satisfy the conditions that “δ/z≧85 and ρ_s≦304Ω/□” or the condition that “115Ω/□≦ρ_s≦304Ω/□.” If the surface resistivity ρ_s of the electrode film 37 is not more than 304Ω/□, excessive radio-frequency electric current can be reliably prevented flowing in a wafer W from the second radio-frequency power source 29. As a result, degradation of a gate oxide film in a specialized device on a wafer W can be prevented.

The condition that “δ/z≧85” for preventing degradation of a gate oxide film in a device having a normal antenna ratio can be converted into the following equation (5):

z≦(ρ_v/(μπf))^1/2/85   (5)

Also, the condition that “ρ_s≦2.67×10⁵Ω/□” for preventing degradation of a gate oxide film in a device having a normal antenna ratio can be converted into the following equation (6):

z≧ρ_v/(2.67×10⁵)   (6)

That is, the electrode film 37 has to satisfy the above equations (5) and (6) so as to prevent degradation of a gate oxide film in a device having a normal antenna ratio.

FIG. 6 is a graph showing a range that satisfies the above equations (5) and (6) when the abscissa indicates the specific resistance of the electrode film 37, the ordinate indicates the thickness of the electrode film 37, and only the abscissa is logarithmically indicated. FIG. 7 is a graph showing a range that satisfies the above equations (5) and (6) when the abscissa indicates the specific resistance of the electrode film 37, the ordinate indicates the thickness of the electrode film 37, and both the abscissa and the ordinate are logarithmically indicated.

In the graphs of FIGS. 6 and 7, the solid line corresponds to the above equation (5), and the broken line corresponds to the above equation (6). Thus, the thickness and the specific resistance of the electrode film 37 have to be within a range surrounded by the solid line and the broken line.

Referring to the graph of FIG. 6, it is only necessary for the specific resistance of the electrode film 37 to be from 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm in the case that the thickness of the electrode film 37 is from several μm to 110 μm so that the thickness and the specific resistance of the electrode film 37 can fall within the range surrounded by the solid line and the broken line (corresponding to the diagonally shaded area in FIG. 6). Also, referring to the graph of FIG. 7, it is only necessary for the specific resistance of the electrode film 37 to be not more than 1.0×10² Ω·cm in the case that the thickness of the electrode film 37 is not more than 10 μm (corresponding to the diagonally shaded area in FIG. 7). That is, in the present embodiment, the thickness of the electrode film 37 is set to several μm to 110 μm, and the specific resistance of the electrode film 37 is set to 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm, or the thickness of the electrode film 37 is set to several μm to 10 μm or less, and the specific resistance of the electrode film 37 is set to 1.0×10² Ω·cm or less. For this reason, the electrode film 37 can reliably satisfy the conditions that “δ/z≧85” and “ρ_s≦2.67×10⁵Ω/□” for preventing degradation of a gate oxide film in a device having a normal antenna ratio.

In the case that the thickness of the electrode film 37 is set to several μm to 110 μm, and the specific resistance of the electrode film 37 is set to 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm, relatively large variations in thickness and specific resistance are tolerated, and hence from the viewpoint of the ease of manufacturing, it is preferred that the electrode film 37 is formed by any of thermal spraying, sintering, and coating of a conductive material (for example, screen printing). Also, in the case that the thickness of the electrode film 37 is set to 10 μm or less, and the specific resistance of the electrode film 37 is set to 1.0×10² Ω·cm or less, a tolerated thickness corresponds to the so-called thickness of a thin film, and hence it is preferred that the electrode film 37 is formed by a thin-film formation such as CVD, PVD, or liquid deposition.

Moreover, the condition that “δ/z≧=85” for preventing degradation of a gate oxide film in a specialized device can be converted into the above equation (5). Also, the condition that “ρ_s≦304Ω/□” for preventing degradation of a gate oxide film in a specialized device can be converted into the following equation (7):

z≧ρ_v/304   (7)

That is, the electrode film 37 has to satisfy the above equations (5) and (7) so as to prevent degradation of a gate oxide film in a specialized device.

FIG. 8 is a graph showing a range that satisfies the above equations (5) and (7) when the abscissa indicates the specific resistance of the electrode film 37, the ordinate indicates the thickness of the electrode film 37, and both the abscissa and the ordinate are logarithmically indicated.

In the graph of FIG. 8, the solid line corresponds to the above equation (5), and the broken line corresponds to the above equation (7). Thus, the thickness and the specific resistance of the electrode film 37 have to be within a range surrounded by the solid line and the broken line.

Here, referring to the graph of FIG. 8, it is only necessary for the specific resistance of the electrode film 37 to be from 1.0×10⁻⁶ Ω·cm to 0.1 Ω·cm in the case that the thickness of the electrode film 37 is from 1.0×10⁻³ μm to 10 μm so that the thickness and the specific resistance of the electrode film 37 can be within the range surrounded by the solid line and the broken line (corresponding to the diagonally shaded area in FIG. 8). That is, in the present embodiment, the thickness of the electrode film 37 may be set to 1.0×10⁻³ μm to 10 μm, and the specific resistance of the electrode film 37 is set to 1.0×10⁻⁶ Ω·cm to 0.1 Ω·cm. For this reason, the electrode film 37 can satisfy the conditions that “δ/z≧85” and “ρ_s≦304Ω/□” for preventing degradation of a gate oxide film in a specialized device.

Here, the tolerable ranges of both the thickness and the specific resistance of the electrode film 37 are narrow, but a metallic thin film such as copper or aluminum formed by PVD or the like has a specific resistance of 1.0×10⁻⁶ Ω·cm to 1.0×10⁻⁴ Ω·cm and varies in thickness within the single digits, and it is thus preferred that the electrode film 37 is comprised of a metallic thin film such as copper or aluminum formed by PVD or the like. It should be noted that in the case that the electrode film 37 is constructed by thermal spraying, sintering, or the like, and the thickness thereof is set to several μm to 110 μm, the specific resistance of the electrode film 37 has to be selected from a very narrow range from 0.01 Ω·cm to 10 Ω·cm.

In the plasma processing apparatus 10 described above, if the resistance R_W of the wafer W is small in the case that high-output radio-frequency electrical power is supplied from the first radio-frequency power source 28, the radio-frequency electrical current from the first radio-frequency power source 28 may flow from the central portion to the peripheral edge portion of the wafer W instead of falling down from the central portion of the wafer W toward the dielectric layer 21. As a result, it is difficult to produce an electric field resulting from the radio-frequency electrical power falling down to the dielectric layer 21 and passing through the wafer W.

If the electric field passing through the wafer W is hardly produced, TM mode hollow cylindrical resonance does not occur in the central portion of the wafer W, the electron density of the plasma increases in the central space, and the distribution of etching speeds over the surface of the wafer W becomes non-uniform as described above. Moreover, galvanic electric current as shown in FIG. 2B is produced, and as a result, the gate oxide film in the device on the wafer W is damaged and degraded due to charge-up.

Here, as is the case with the skin depth δ_w of the electrode film 37, the skin depth δ_w of the wafer W is expressed by the following equation (8):

δ_w=(2ρ_vw/μ_wω)^1/2=(ρ_vw/(μ_wπf))_1/2   (8)

where μ_w is a magnetic permeability (H/m) of the wafer W, ω is 2 πf (π: the ratio of the circumference of a circle to its diameter, and f: the frequency (Hz) of radio-frequency electrical power supplied from the first radio-frequency power source 28), and ρ_vw is a specific resistance (Ω·m) of an electrode material constituting the wafer W.

The permeability (E_w/E_0w) at which the electric field of the radio-frequency electrical power supplied from the first radio-frequency power source 28 passes through the wafer W is proportional to “exp(−z_w/δ_w)” as expressed by the following equation (9):

E_w/E_0w∝exp(−z_w/δ_w).   (9)

Where z_w is the thickness (m) of the wafer W, and E_0w is the intensity of the electric field incident on the wafer W.

As is obvious from the above equation (9), it was found that to produce an electric field passing through the wafer W, it is only necessary to increase the skin depth δ_w of the wafer W, and to increase the skin depth δ_w of the wafer W, it is only necessary to increase the resistance R_w of the wafer W using an electrode material having a high specific resistance ρ_vw.

Accordingly, the inventors of the present invention prepared a plurality of test wafers having different specific resistances ρ_vw so as to find a specific resistance ρ_vw of the wafer W that can make the distribution of etching speeds over the surface of the wafer W uniform. Then, the inventors of the present invention carried out the RIE on the test wafers in the plasma processing apparatus 10, observed the distribution of etching speeds over the surfaces of the test wafers, and graphed the observation results in FIG. 9. The specific resistances ρ_vw of the respective test wafers used here were 1.9 Ω·cm and 4.0 Ω·cm.

Moreover, in the RIE, a mixed gas of N₂ gas, O₂ gas, and CH₄ gas (flow ratio: N₂ gas/O₂ gas/CH₄ gas=100/10/45 sccm) was introduced as a process gas into the upper chamber 11a, the frequency of radio-frequency electrical power supplied from the first radio-frequency power source 28 was set to 100 MHz, the value thereof was set to 2400 W, the frequency of radio-frequency electrical power supplied from the second radio-frequency power source 29 was set to 3.2 MHz, and the value thereof was set to 200 W.

In the graph of FIG. 9, the abscissa indicates the distance from the center of the test wafer, and the ordinate indicates the etching speed (nm/min). The broken line corresponds to the case that the specific resistances ρ_vw=1.9 Ω·cm, and the solid line corresponds to the case that the specific resistances ρ_vw=4.0 Ω·cm.

From the graph of FIG. 9, it was found that if the specific resistances ρ_vw is not less than 4.0 Ω·cm, the distribution of etching speeds over the surface of the wafer W can be made substantially uniform. Moreover, because the test wafers had a thickness of 775 μm and a diameter of 300 mm, it was found from the above results that if δ_w/z_w is not less than 13, or the surface resistivity ρ_sw of the wafer W is not less than 52Ω/□, the distribution of etching speeds over the surface of the wafer W can be made substantially uniform.

Moreover, if the resistance R₁ of a wiring film, not shown, on the wafer W is low, radio-frequency electric current from the second radio-frequency power source 28 may flow from the central portion to the peripheral edge portion of the wafer W via the wiring film instead of falling down from the central portion down toward the dielectric layer 21. As a result, as described above, the distribution of etching speeds over the surface of the wafer W becomes non-uniform, and galvanic electric current as shown in FIG. 2B is produced, and the gate oxide film in the device on the wafer W is damaged and degraded due to charge-up.

Accordingly, to produce an electric field passing through the wiring film, it is only necessary to increase the skin depth δ₁ of the wiring film expressed by the following equation (10), and to increase the skin depth δ₁ of the wiring film, it is only necessary to increase the resistance R₁ of the wiring film using an electrode material having a high specific resistance ρ_v1:

δ₁=(2ρ_v1/(μ₁ω))^1/2=(ρ_v1/(μ₁πf))^1/2   (10)

where μ is a magnetic permeability (H/m) of the wiring film, ω is 2 πf (π: the ratio of the circumference of a circle to its diameter, and f: the frequency (Hz) of radio-frequency electrical power supplied from the first radio-frequency power source 28), and ρ_v1 is a specific resistance (Ω·m) of an electrode material of the wiring film.

Here, because δ_w/z_w of the wafer W has to be not less than 13, and the surface resistivity ρ_sw of the wafer W has to be not less than 52Ω/□ so as to make the distribution of etching speed over the surface of the wafer W substantially uniform as described above, δ₁/z₁ of the wiring film is also set to be not less than 13, and the surface resistivity of the wiring film is also set to be not less than 52Ω/□. It should be noted that z₁ is the thickness (m) of the wiring film.

FIG. 10 is an enlarged cross-sectional view schematically showing the construction of the electrostatic chuck in FIG. 1 and its vicinity.

Referring to FIG. 10, the electrostatic chuck 22 has a disk-shaped base material 22a that is made of a sintered material such as ceramics, the electrode film 37 that is formed on a surface (upper side as viewed in the drawing) of the base material 22a, a disk-shaped upper material 22b (insulating material) that is made of a sintered material which is ceramics, laminated on the electrode film 37, and attached to the electrode film 37 and the base material 22a by pressure, and a cylindrical conductive member 45 that has one end thereof being in contact with the electrode film 37 and has the other end thereof being exposed from a rear surface (lower side as viewed in the drawing) of the base material 22a.

The electrostatic chuck 22 is mounted on the upper surface of the lower electrode 20 and attached to the lower electrode 20 by an insulating adhesive agent 46 (for example, an adhesive agent with a filler). At this time, the other end of the conductive member 45 is electrically connected to the high-voltage DC power source 42 via a conducting bar 47. Thus, the high-voltage DC power source 42 can supply high-output DC voltage to the electrode film 37.

Next, a description will be given of how the electrostatic chuck 22 is manufactured.

First, the base material 22a is prepared/formed in advance, and the electrode film 37 is formed on a surface of the base material 22a by screen printing.

Then, the base material 22a and the electrode film 37 are covered with the upper material 22b that is separately prepared/formed, and the base material 22a, electrode film 37, and upper material 22b are attached to one another by pressure through hot pressing, and the electrode film 37 is hardened and stabilized in its physicality, whereby the electrostatic chuck 22 is obtained.

In the screen printing, Al₂O₃—MoC or a carbon-containing material is used. By adjusting the contained amount of MoC or carbon, the electrode film 37 whose specific resistance lies inside a semiconductor region, specifically, 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm can be easily formed. In general, because a film with a thickness of several μm to 100 μm can be suitably formed in the screen printing, the screen printing can be used as a method of forming the electrode film 37 whose thickness has to be set to several μm to 100 μm in the case that the specific resistance is set to 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm.

As described above, the electrode film 37 of the present embodiment has to have the skin depth δ and the thickness Z satisfying the condition that “δ/z≧85”, and the surface resistivity ρ_s satisfying the condition that “ρ_s≦2.67×10⁵Ω/□”, it is necessary to manage the surface resistivity ρ_s of the electrode film 37. However, as described above, in the case that the electrode film 37 is formed by the screen printing and further hardened by the hot pressing, the electrode film 37 is covered with the upper material 22b and then hardened to be stabilized in its property, and it is thus impossible to measure the resistance value of the electrode film 37 in the process of manufacturing the electrostatic chuck 22. To cope with this, in the present embodiment, as a method of forming the electrode film 37 in the electrostatic chuck 22, thermal spraying, thin-film formation, coating (except for screen printing), attachment of a conductive film (for example, a metallic thin film), or the like is used.

In the thermal spraying, for example, the electrode film 37 having a specific resistance inside a semiconductor region, specifically, a specific resistance of 1.0×10⁻² Ω·cm to 1.0×10³ Ω·cm can be easily formed by using Al₂O₃—Cr₂O₃ or silicon as a thermal spraying material. In general, because a film having a thickness of several μm to 100 μm can be suitably formed in the thermal spraying, the thermal spraying is preferable as the method of forming the electrode film 37. Also, in the coating, a thermosetting coating, for example, a carbon-containing material is used, and the electrode film 37 is formed by heating and hardening the coated coating.

Examples of the thin-film formation include PVD in which a thin film of copper, aluminum, or gold is formed, CVD or liquid deposition in which a thin film of tungsten or titanium is formed, plating method (electroless nickel plating) or a sol-gel method. By using these kinds of thin-film formation, the electrode film 37 having a specific resistance inside a low resistance region, specifically, a specific resistance of 1.0×10⁻⁶ Ω·cm to 0.1 Ω·cm and having a thickness of 10 μm or less can be easily formed.

By using the thermal-spraying, coating, and thin-film formation described above, the electrode film 37 can be hardened and stabilized in physical properties before the electrode film 37 is covered with the upper material 22b, that is, in a state of being exposed.

In the method of manufacturing the electrostatic chuck 22 according to the present embodiment, at the time point when the electrode film 37 is hardened, the surface resistivity ρ_s, thickness z, and so on of the electrode film 37 are measured, it is determined whether or not the skin depth δ and the thickness z of the electrode film 37 satisfy the condition that “δ/z≧85” and the surface resistivity ρ_s satisfies the condition that “ρ_s≦2.67×10⁵Ω/□”, or whether or not the surface resistivity ρ_s of the electrode film 37 satisfies the condition that “115 Ω/□≦ρ_s≦2.67×10⁵Ω/□.” If the electrode film 37 does not satisfy these conditions, the base material 22a and the electrode film 37 are discarded. After that, the base material 22a and the electrode film 37 are covered with the upper material 22b, and the base material 22a, electrode film 37, and upper material 22a are attached to one another by pressure, whereby the electrostatic chuck 22 is obtained.

According to the method of manufacturing the electrostatic chuck 22 described above, because the electrode film 37 is formed on the surface of the base material 22a prepared/formed in advance, and then covered with the upper material 22b, the electrode film 37 exposes itself once without exception before being covered with the upper material 22b in the process of manufacturing the electrostatic chuck 22. This makes it possible to measure the surface resistivity ρ_s and so on of the electrode film 37 in the process of manufacturing the electrostatic chuck 22 and thus makes it possible to manage the surface resistivity ρ_s and so on of the included electrode film 37.

Although in the electrostatic chuck 22 described above, the upper material 22b is attached to the electrode film 37 and the base material 22a by pressure, the upper material 22b may be attached to the base material 22a and the electrode film 37 by an insulating adhesive agent, not shown. The insulating adhesive agent can reliably insulate high-power DC voltage applied to the electrode film 37, and reliably attach the upper material 22b to the base material 22a.

Although in the electrostatic chuck 22 described above, the electrode film 37 is formed on the surface of the upper material 22b, a dielectric layer 48 that is constructed such as to cover the whole upper surface of the lower electrode 20 may be buried in the lower electrode 20, the electrode film 37 may be directly formed on an upper surface of the dielectric layer 48, and then the upper material 22b may be attached to the electrode film 37 and the dielectric layer 48 by pressure. This can reduce the number of component parts of the mounting stage 12. The dielectric layer 48 is formed by sintering or thermal spraying of ceramics, or a combination of both.

Moreover, the electrode film 37 may be formed on a rear surface (lower side as viewed in the drawing) of the upper material 22b (base material) by the thermal spraying or thin-film formation described above, and the upper material 22b may be attached to the dielectric layer 48 by an insulating adhesive agent 46 (FIG. 11A). At this time, a layer comprised of an insulating adhesive agent is not superposed between a surface (an upper side as viewed in the drawing) that acts as an upper surface of the electrostatic chuck 22 and directly contacts the wafer W and the electrode film 37, the electrostatic attracting force with which the electrostatic chuck 22 electrostatically attracts a wafer W becomes more stable. It should be noted that in the case that the electrode film 37 is formed on the rear surface of the upper material 22b, it is preferred that the surface of the electrode film 37 is coated with an insulating coating film. This can improve the insulation performance of the electrostatic chuck 22. The insulating coating film corresponds to the base material 22a appearing in FIG. 10 and is formed by the thermal spraying, the thin-film formation, or the like.

In the electrostatic chuck 22 described above, because the upper material 22b is a sintered material, the wafer W that is electrostatically attracted by the electrostatic chuck 22 contacts the sintered material. Because the sintered material is unlikely to fracture, a surface layer of the upper material 22b does not fracture even if the upper material 22b contacts the wafer W. Thus, particles resulting from the fracture of the surface layer of the upper material 22b can be prevented from being produced. Moreover, in the case that the electrode film 37 is formed on the rear surface of the upper material 22b comprised of the sintered material by the thermal spraying, it is preferred that an underlayer with high wettability is formed in advance on the rear surface of the upper material 22b (the surface facing the base material) so as to increase the degree of bonding between the sintered material and the electrode film 37 formed by the thermal spraying. This can further increase bonding force with which the upper material 22b and the electrode film 37 formed by the thermal spraying are bonded together.

Although in the electrostatic chuck 22 described above, the sintered material is used as the upper material 22b, the upper material 22b may be formed by thermal spraying of an insulating material or attachment of an insulating film. This can reliably form an insulating layer on the electrode Film 37.

In the case that the upper material 22b is formed on the electrode film 37 by thermal spraying of insulating ceramics such as Al₂O₃, it is preferred that the electrode film 37 is also formed on the surface of the base material 22a by thermal spraying. This makes it possible to form almost all of the electrostatic chuck 22 by thermal spraying, and thus manufacture the electrostatic chuck 22 at low cost.

In the case that the upper material 22b is formed by attachment of an insulating film, an electrostatic chuck 49 may be constructed by attaching a conductive tape 50 of which a metallic thin film is evaporated on the base material 22a prepared/formed in advance, and attaching an insulating film, for example, a polyimide tape 51 on the conductive tape 50 (FIG. 11B). In this case, it is preferred that the metallic thin film evaporated on the tape 50 is made of, for example, copper or aluminum.

Moreover, although in the electrostatic chuck 22 described above, the electrode film 37 and the base material 22a are configured as separate bodies, a base material 52 may be made of a sintered material comprised of a tight layer 52a and a loose layer 52b formed on the tight layer 52a, and a conductive material may be impregnated in the loose layer 52b to configure an electrode layer 53 and the base material 52 as an integral unit (see FIGS. 12A and 12B). In this case, it is preferred that after the electrode layer 53 is formed, the base material 52 and the electrode layer 53 are covered with the upper material 22b separately prepared/formed, and the base material 52, electrode layer 53, and upper material 22b are attached to one another by pressure. This causes the electrode layer 53 to expose itself once without exception before being covered with the upper material 22b in the process of manufacturing the electrostatic chuck. As a result, in the process of manufacturing the electrostatic chuck, the surface resistivity ρ_s and so on of the electrode layer 53 can be measured, and hence the surface resistivity ρ_s of the included electrode layer 53 can be managed. Moreover, because the base material 52 has the loose layer 52b, the conductive material can be reliably impregnated in the base material 52.

Further, conductive linear members may be combined together in a mesh-like fashion to construct an electrode film 54 (FIG. 13). In the electrode film 54, the surface resistivity ρ_s per unit area can be easily adjusted by adjusting the size of meshes.

It should be noted that in the case that the electrode film 37 is formed by screen printing and then hardened by the hot pressing, the electrode film 37 never exposes itself in the hardened state in the process of manufacturing the electrostatic chuck 22, and hence the resistance value of the electrode film 37 cannot be measured in the process of manufacturing the electrostatic chuck 22. In this case, it is preferred that the electrostatic chuck 22 is provided with at least two conductive members 45, and in particular, it is preferred that one of the conductive members 45 is disposed in the central portion of the electrostatic chuck 22. Specifically, one conductive member 45 is disposed in the central portion of the electrostatic chuck 22, and the other plurality of conductive members 45 are disposed at regular intervals on the same circumference in a peripheral edge portion of the electrostatic chuck 22 (FIGS. 14A and 14B). In this case, by bringing two terminals of a tester into contact with the respective two conductive members 45, the surface resistivity ρ_s of the electrode film 37 can be measured and managed with ease after the electrostatic chuck 22 is manufactured. In particular, if one of the two terminals of the tester is brought into contact with the conductive members 45 disposed in the central portion of the electrostatic chuck 22, the surface resistivity ρ_s of the electrode film 37 can be managed by measuring the resistance from the central portion to the peripheral edge portion of the electrode film 37.

Although in the above described embodiment, the substrates subjected to the RIE or the ashing are semiconductor wafers W, but the substrates subjected to the RIE or the ashing are not limited to being semiconductor wafers W, and rather may instead be any of various glass substrates used in LCDs (Liquid Crystal Displays), FPDs (Flat Panel Displays), or the like.

Claims

1. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising:

a conductor member connected to a radio-frequency power source for producing plasma;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following condition: δ/z≧85

where δ=(ρv/(μπf))1/2

where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, and ρv is a specific resistance of the electrode film.

2. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising: where ρs is a surface resistivity of the electrode film.

a conductor member connected to a radio-frequency power source for attracting ions;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following condition: ρs≦2.67×105Ω/□

3. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising:

a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following conditions: δ/z≧85 and ρ5≦2.67×105Ω/□

where δ=(ρv/μπf))1/2

where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, ρv is a specific resistance of the electrode film, and ρs is a surface resistivity of the electrode film.

4. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising: where ρs is a surface resistivity of the electrode film.

a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source and comprises an electrode film that satisfies the following conditions: 115 Ω/□≦ρs≦2.67×105Ω/□

5. A mounting stage for a plasma processing apparatus as claimed in claim 2, wherein the surface resistivity ρs is not more than 304Ω/□.

6. A mounting stage for a plasma processing apparatus as claimed in claim 1, wherein the electrode film is formed by one of thermal spraying, sintering and coating, and the specific resistance of the electrode film is 1.0×10−2 Ω·cm to 1.0×103 Ω·cm.

7. A mounting stage for a plasma processing apparatus as claimed in claim 1, wherein the electrode film is formed by one of CVD, PVD, and liquid deposition, a thickness of the electrode film is not more than 10 μm, and the specific resistance of the electrode film is not more than 1.0×102 Ω·cm.

8. A mounting stage for a plasma processing apparatus as claimed in claim 1, wherein a frequency of radio-frequency electrical power supplied from the radio-frequency power source for producing plasma is not less than 27 MHz.

9. A mounting stage for a plasma processing apparatus as claimed in claim 2, wherein a frequency of radio-frequency electrical power supplied from the radio-frequency power source for attracting ions is not more than 27 MHz.

10. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and

the substrate satisfies the following condition: δw/zw≧13

where δw=(ρvw/(μwπf))1/2

where zw is a thickness of the substrate, δw is a skin depth of the substrate with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μw is a magnetic permeability of the substrate, and ρvw is a specific resistance of the substrate.

11. A plasma processing apparatus comprising: where ρsw is a surface resistivity of the substrate.

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and

the substrate satisfies the following condition: ρsw≧52Ω/□

12. A plasma processing apparatus comprising: where ρvw is a specific resistance of the substrate.

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and

the substrate satisfies the following condition: ρvw≧4 Ω·cm

13. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and

a wiring film on the substrate satisfies the following condition: δ1/z1≧13

where δ1=(ρv1/(μ1πf))1/2

where z1 is a thickness of the wiring film, δ1 is a skin depth of the wiring film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ1 is a magnetic permeability of the wiring film, and ρv1 is a specific resistance of the wiring film.

14. A plasma processing apparatus comprising: where ρs1 is a surface resistivity of the wiring film.

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck has an electrode film connected to a high-voltage direct current power source, and

a wiring film on the substrate satisfies the following condition: ρs1≧52 Ω/□

15. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: δ/z≧85

where δ=(ρv/(μπf))1/2

where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, and ρv is a specific resistance of the electrode film.

16. A plasma processing apparatus comprising: where ρs is a surface resistivity of the electrode film.

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: ρs≦2.67×105Ω/□

17. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried In a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following conditions: δ/z≧85 and ρs≦2.67×105Ω/□

where δ=(ρv/(μπf))1/2

where z is a thickness of the electrode film, δ is a skin depth of the electrode film with respect to radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source for producing plasma, π is a ratio of a circumference of a circle to its diameter, μ is a magnetic permeability of the electrode film, ρv is a specific resistance of the electrode film, and ρs is a surface resistivity of the electrode film.

18. A plasma processing apparatus comprising: where ρs is a surface resistivity of the electrode film.

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source for producing plasma and a radio-frequency power source for attracting ions, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-voltage direct current power source and has an electrode film that satisfies the following condition: 115Ω/□≦ρs≦2.67×105Ω/□

19. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising:

a conductor member connected to a radio-frequency power source;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and

the electrode film is formed on an upper surface or a lower surface of a plate-shaped base material comprising a dielectric member prepared/formed in advance, and coated with an insulating material after the electrode film is formed.

20. A mounting stage for a plasma processing apparatus as claimed in claim 19, wherein the electrode film is formed by thermal spraying, coating, thin-film formation, and attachment of a conductive film.

21. A mounting stage for a plasma processing apparatus as claimed in claim 20, wherein the thin-film formation is one of CVD, PVD, and liquid deposition.

22. A mounting stage for a plasma processing apparatus as claimed in claim 19, wherein the insulating material is formed by one of sintering, thermal spraying, and attachment of an insulating film.

23. A mounting stage for a plasma processing apparatus on which a substrate is mounted, comprising:

a conductor member connected to a radio-frequency power source;

a dielectric layer buried in a central portion of an upper surface of said conductor member; and

an electrostatic chuck mounted on said dielectric layer,

wherein said electrostatic chuck is connected to a high-voltage direct current power source, includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and further has at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof being exposed from a surface of said electrostatic chuck.

24. A mounting stage for a plasma processing apparatus as claimed in claim 23, wherein at least one of the two conductive members is disposed in a central portion of said electrostatic chuck.

25. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source, a dielectric layer buried in a central portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-voltage direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and

the electrode film is formed on an upper surface or a lower surface of a plate-shaped base material comprising a dielectric member prepared/formed in advance, and coated with an insulating material after the electrode film is formed.

26. A plasma processing apparatus comprising:

a mounting stage on which a substrate is mounted,

wherein said mounting stage comprises a conductor member connected to a radio-frequency power source, a dielectric layer buried in a control portion of an upper surface of the conductor member, and an electrostatic chuck mounted on the dielectric layer,

the electrostatic chuck is connected to a high-power direct current power source and includes an electrode film for which at least one of an upper limit value and a lower limit value of a surface resistivity is set, and further has at least two conductive members having one end thereof being in contact with the electrode film and the other end thereof exposed from a surface of the electrostatic chuck.

27. A plasma processing apparatus comprising:

a mounting stage for the plasma processing apparatus as claimed in claim 1,

wherein the substrate mounted on said mounting stage satisfies the following condition: δw/zw≧13

where δw=(ρvw/(μwπf))1/2

where zw is a thickness of the substrate, δw is a skin depth of the substrate with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μw is a magnetic permeability of the substrate, and ρvw is a specific resistance of the substrate.

28. A plasma processing apparatus comprising: where ρsw is a surface resistivity of the substrate.

a mounting stage for the plasma processing apparatus as claimed in claim 1,

wherein the substrate mounted on said mounting stage satisfies the following condition: ρsw≧52 Ω/□

29. A plasma processing apparatus comprising: where ρvw is a specific resistance of the substrate.

a mounting stage for the plasma processing apparatus as claimed in claim 1,

wherein the substrate mounted on said mounting stage satisfies the following condition: ρvw≧4 Ω·cm

30. A plasma processing apparatus comprising:

a mounting stage for the plasma processing apparatus as claimed in claim 1,

wherein a wiring film on the substrate mounted on said mounting stage satisfies the following condition: δ1/z1≧13

where δ1=(ρv1/(μ1πf))1/2

where z1 is a thickness of the wiring film, δ1 is a skin depth of the wiring film with respect to radio-frequency electrical power supplied from the radio-frequency power source, f is a frequency of the radio-frequency electrical power supplied from the radio-frequency power source, π is a ratio of a circumference of a circle to its diameter, μ1 is a magnetic permeability of the wiring film, and ρv1 is a specific resistance of the wiring film.

31. A plasma processing apparatus comprising: where ρs1 is a surface resistivity of the wiring film.

a mounting stage for the plasma processing apparatus as claimed in claim 1,

wherein a wiring film on the substrate mounted on said mounting stage satisfies the following condition: ρs1≧52 Ω/□