Method for generating plasma method for cleaning and method for treating substrate
A plasma generation method in a toroidal plasma generator that includes a gas passage having a gas entrance and a gas outlet and forming a circuitous path and a coil wound around a part of the gas passage includes the steps of supplying a mixed gas of an Ar gas and an NF3 gas containing at least 5% of NF3 and igniting plasma by driving the coil with a high-frequency power, wherein the plasma ignition step is conducted under a total pressure of 6.65-66.5 Pa.
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The present invention generally relates to fabrication of semiconductor devices and more particularly to a cleaning method and substrate processing method that uses plasma. Further, the present invention related to a plasma generator and particularly to a plasma ignition method.
Plasma generator is used extensively in fabrication of semiconductor devices or liquid crystal display devices. For example, with the use of plasma generator, it becomes possible to carry out film formation processing or etching processing at a low temperature in which there is caused no change of concentration profile of impurity elements formed in a semiconductor substrate. Further, plasma generator is used also for cleaning the interior of processing vessel after conducting a substrate processing therein.
BACKGROUND ART
Referring to
The source supplying system 15 includes source gas sources 15A-15C wherein the source gas in the source gas source 15A is supplied to the line L1 via a valve 15A while the source gas in the source gas source 15B is supplied to the line L1 via a valve 15VB. Further, the source gas in the source gas source 15C is supplied to the line L1 via a valve 15VC.
The source gas supplied via the line L1 is released to a processing space inside the processing vessel 11 via the showerhead 14, and desired film formation occurs at the surface of the substrate 12 to be processed as a result of the decomposition reaction taking place at the surface of the substrate 12A to be processed.
With the single-wafer CVD apparatus 10 of
With the single-wafer CVD apparatus 10 constituting such a single-wafer processing system, the substrate temperature is controlled during the film forming processing by a heating device formed in the susceptor 12 while the wall surface of the processing vessel 10 is maintained at a relatively low temperature from room temperature to 150° C. (cold wall).
With such a cold wall type CVD apparatus, it is inevitable that there is caused some deposition of reactants on the inner wall surface of the processing vessel 11 at the time of film deposition on the substrate 12A to be processed, and thus, it has been practiced to conduct a cleaning process for removing the deposits by causing to flow a cleaning gas acting an etchant to the interior of the processing vessel 11 each time film formation processing for one or plural substrates has been completed.
Particularly, with the CVD apparatuses used for fabrication of ultra-miniaturized semiconductor devices of these days, it is preferable to conduct the cleaning process as frequently as possible, ideally each time a substrate is processed, for recovering the predetermined initial processing condition. However, when such frequent cleaning processing has been conducted, the cleaning time associated with the cleaning processing causes serious decrease in the throughput of semiconductor production.
Thus, with the CVD apparatus of
In
For the cleaning gas containing fluorine, it is also possible to use a non-halogen compound such as CH3COOH, in addition to the halogen compound such as NF3. Further, it is possible to use He, Ne, Kr, Xe, or the like, for the diluting gas from the plasma gas source 16B in place of Ar. Further, the diluting gas is not limited to a rare gas and it is also possible to use the gases such as H2O, O2, H2, N2, C2F6, or the like, for the diluting gas.
With regard to such a remote plasma source 16C, it is possible to use any of an induction coupled type plasma (ICP) generator 20 shown in
With the ICP type plasma generator 20 of
With the ECR plasma generator 30 of
With the helicon-wave type plasma generator 40 of
With the microwave cavity type plasma generator 50 of
With the toroidal plasma generator 60 of
Thus, a rare gas such as Ar introduced into the gas passage 61A circles around the cyclic gas passage 61, wherein plasma is induced in the rare gas by driving the high-frequency coil 62 by a microwave.
With the CCP-type plasma generator 70 of
Particularly, with the toroidal plasma generator of
Referring to
Thus, the rare gas such as Ar introduced into the gas entrance 61A circles around the circular gas passage 61, and plasma is induced in the foregoing rare gas by driving the high-frequency coil 62 by a high-frequency power. Thereby, there is formed a cyclic current path shown in
Thus, with the toroidal plasma generator 60 of
PATENT REFERENCE 1 U.S. Pat. No. 6,374,831.
DISCLOSURE OF THE INVENTION Problems to be Solves by the Invention Thus, with the toroidal plasma generator 60 of
Referring to
Referring to
Referring to
The results of
Further,
Referring to
From
Thus, with the toroidal plasma generator 60 of
In order to circumvent this problem of plasma ignition, it has been practiced in the art to supply the Ar 100% gas at the time of ignition of the remote plasma source 16C and the etching gas containing fluorine is supplied after the plasma has been formed. Reference should be made to Patent Reference 1, for example. Further, plasma ignition has been conducted also in the experiments explained with reference to
However, such a conventional approach requires sufficient purging of the cyclic gas passage 61 with regard to the NF3 gas at the time of the plasma ignition for achieving plasma ignition, and there arises a problem of serious degradation of processing throughput with the fabrication of recent ultra miniaturized semiconductor devices such as the one fabricated with the design rule of 1 μm or less, in which there is needed frequent cleaning of the processing vessel. For example, a very long time would be needed for the substrate processing when cleaning of the processing vessel 11 is to be conducted each time a substrate has been processed.
Further, in any of the conventional plasma generators of
Thus, the present invention has its general object of providing a novel and useful plasma ignition method and a method of cleaning and substrate processing method wherein the foregoing problems are eliminated.
Another object of the present invention is to provide a plasma ignition method that can achieve plasma ignition for a mixed gas of an Ar gas and an NF3 gas while using a toroidal plasma generator, and a substrate processing method that uses such a toroidal plasma generator.
Another object of the present invention is to provide a plasma cleaning method capable of igniting plasma at low voltage and thus capable of avoiding high-voltage damaging in power supplies, coils, electrodes, and the like.
Means of Solution of the ProblemsThe present invention provides a method of generating plasma in a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil wound around a part of the gas passage,
characterized in that said method comprises the steps of supplying a mixed gas of an Ar gas and an NF3 gas containing at least 5% of said NF3 gas, and igniting plasma by driving said coil with a high-frequency power,
said step of igniting plasma being conducted under a total pressure of 6.65-66.5 Pa.
Further, the present invention provides a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil would around a part of said gas passage,
characterized in that said method comprises the steps of supplying a mixed gas of an Ar gas and a F2 gas containing at least 5% of said F2 gas, and igniting plasma by driving said coil with a high-frequency power,
said step of igniting plasma being conducted under a total pressure of 6.65-66.5 Pa.
Further, the present invention provides a cleaning method for cleaning a processing vessel evacuated by an evacuating system and coupled with a remote plasma source,
said remote plasma source comprising a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil would around a part of said gas passage,
characterized in that said cleaning method comprises the steps of:
forming radicals containing F in said remote plasma source; and
supplying said radicals to an interior of said processing vessel and cleaning said interior of said processing vessel by said radicals,
said step of forming said radicals comprising the steps of:
supplying a mixed gas containing at least 5% of NF3 or F2 in an Ar gas to said gas passage as a cleaning gas with a first pressure in which plasma can ignite and igniting plasma by driving said coil by a high-frequency power; and
increasing a total pressure of said mixed gas in said gas passage to a second pressure while maintaining said plasma,
said cleaning step cleaning said interior of said processing vessel at said second pressure.
Further, the present invention provides a substrate processing method in a processing vessel evacuated by an evacuation system and coupled with a remote plasma source,
said remote plasma source comprising a toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet and forming a circuitous path, and a coil would around a part of said gas passage,
said substrate processing method comprising the steps of:
forming radicals containing F in said remote plasma source; and
etching a surface of a substrate to be processed in said processing vessel by said radicals by supplying said radicals to an interior of said processing vessel,
said step of forming said radicals comprising the steps of:
supplying a mixed gas containing NF3 or F2 in an Ar gas with a concentration of at least 5% to said gas passage under a first pressure in which ignition of plasma is possible and igniting plasma by driving said coil with a high-frequency power; and
increasing a total pressure of said mixed gas in said passage to a second pressure while maintaining said plasma,
said step of etching being conducted under said second pressure.
Further, the present invention provides a cleaning method for cleaning an interior of a processing vessel by plasma-excited radicals of a cleaning gas under a first pressure zone, characterized in that said method comprises the steps of:
introducing a mixed gas of a diluting gas and a cleaning gas to a plasma generator under a second pressure lower than said first pressure and igniting plasma; and
increasing a pressure inside said processing vessel to said first pressure zone from said second pressure zone.
Further, the present invention provides a substrate processing method for etching a surface of a substrate to be processed by plasma-excited radicals under a first pressure zone, comprising the steps of:
introducing a mixed gas of a diluting gas and an etching gas into a plasma generator under a second pressure lower than said first pressure and igniting plasma; and
increasing a pressure inside said processing vessel to said first pressure zone from said second pressure zone.
Further, the present invention provides a cleaning method for cleaning an interior of a processing vessel by plasma-excited radicals of a cleaning gas under a first pressure zone, comprising the steps of:
introducing a mixed gas of a diluting gas and a cleaning gas into a plasma generator under a second flow rate zone smaller than said first flow rate zone and igniting plasma; and
increasing a flow rate of said mixed gas from said first flow rate zone to said second flow rate zone.
Further, the present invention provides a substrate processing method for etching a surface of a substrate to be processed in a processing vessel by plasma-excited radicals of etching under a first flow rate zone, comprising the steps of:
introducing a mixed gas of a diluting gas and an etching gas into a plasma generator under a second flow rate zone smaller than said first flow rate zone and igniting plasma; and
increasing a flow rate of said mixed gas from said second flow rate zone to said first flow rate zone.
EFFECT OF THE INVENTIONAccording to the present invention, it becomes possible with a toroidal plasma generator to ignite plasma by a high-frequency power under a total pressure of 6.65-66.5 Pa while supplying a mixed gas of an Ar gas and a NF3 gas containing at least 5% of NF3 and thus it becomes possible to ignite plasma for an Ar/NF3 mixed gas. As a result, it becomes possible to eliminate the purging process of an NF3 gas from a remote plasma source, which has been necessary in single-wafer substrate processing systems whenever there is a need of turning plasma on and off, and it becomes possible to improve the throughput of cleaning or substrate processing significantly. Once the plasma has been ignited, it becomes possible to move from a ignition point of plasma to a processing point where cleaning or etching processing is conducted, without extinguishing the plasma, and efficient plasma process becomes necessary.
Further, according to the present invention, it becomes possible to ignite plasma with low voltage even in a gas containing a halogen compound, by decreasing the gas pressure at the time of plasma ignition. With this, it becomes possible to avoid occurrence of large voltage overshoot caused by large impedance change occurring at the moment of plasma ignition and associated problems of damaging in the driving power source, electrodes or coils. Further, with the present invention, it becomes possible to carry out the desired cleaning process or etching process efficiently after such ignition of plasma, by increasing the gas pressure to a predetermined process condition while sustaining plasma. Further, according to the present invention, it becomes possible to ignite plasma in the gas containing a halogen compound, and thus, the need of purging the gas containing halogen compound each time plasma is to be ignited is no longer necessary in the process where there is a need of turning on and turning off the plasma frequently, as in the case of single-wafer process, and the throughput of cleaning or substrate processing is improved significantly.
BRIEF DESCRIPTION OF THE DRAWINGS
- 10 CVD apparatus
- 11 processing vessel
- 12 susceptor
- 13 vacuum pump
- 13A block valve
- 13B conductance valve
- 14 shower head
- 15 source gas supply system
- 15A-15C source material gas source
- 15VA-15VC valve
- 16 cleaning module
- 16A cleaning gas source
- 16B Ar gas source
- 16a-16d mass flow rate controller
- 16C remote plasma source
- 16VA-16VC valve
- 20 ICP plasma generator
- 21 plasma vessel
- 22 coil
- 23 high-frequency power supply
- 30 ECR plasma generator
- 31 plasma vessel
- 32 magnet
- 33 microwave power supply
- 40 helicon wave plasma generators
- 41 plasma vessel
- 42 loop antenna
- 43 high-frequency power supply
- 44 magnet
- 50 microwave cavity plasma generator
- 51 microwave cavity
- 52 microwave power supply
- 60 toroidal plasma generator
- 61 gas passage
- 61A gas entrance
- 61B gas exit
- 62 high frequency coil
- 70 capacitive-coupled plasma generator
- 71 plasma vessel
- 71A, 71B electrode
- 72 high-frequency power supply
- L1 source gas line
- L2 cleaning gas line
Hereinafter, explanation of the present invention will be made with regard to preferred embodiments.
As explained previously, a toroidal plasma generator has an advantageous feature of reduced contamination in the substrate processing that uses plasma because of suppressed sputtering at the wall surface of the plasma generator, while there is a drawback in that plasma ignition is difficult. Thus there has been a need, when to carry out plasma ignition, of eliminating the etching gas or cleaning gas containing halogen having a large electronegativity such as NF3 and conduct the plasma ignition in an ambient of Ar gas 100%.
Thus, it has been recognized commonly that, with toroidal plasma generator, plasma ignition is possible only in the ambient of 100% Ar gas. Contrary to this, it came to the attention of the inventor of the present invention that average mean path length of electrons is increased under low pressure environment and predicted that electrons would acquire large energy also with toroidal plasma generators when a high frequency electric filed is applied under the low pressure environment such as the one used for ordinary cleaning process or etching process, as a result of large acceleration caused by the electric field, and that there would be a possibility that the plasma is ignited even when a gas containing halogen having large electronegativity such as NF3 is added to the Ar gas under the circumstances in which the electrons have large energy.
Referring to
Thus, with regard to the toroidal plasma generator 60 of
Referring to
Thus, with decrease of the total pressure in the gas passage 21, it can be seen that the range of the NF3 concentration that allows plasma ignition increases and that the range of the NF3 concentration that allows plasma ignition increases also with decrease of the total flow rate of the Ar/NF3 mixed gas.
On the other hand, when the total pressure in the gas passage 61 becomes too low, the probability of the accelerated electrons colliding with an Ar atom or an NF3 molecule is decreased, and ignition of plasma becomes difficult.
From
Further,
Referring to
The relationship of
Thus, according to the present embodiment, it becomes possible to ignite plasma in a toroidal plasma generator even in the case of using an Ar/NF3 mixed gas containing NF3 by 5% or more. Thereby, there is no need of purging the NF3 cleaning gas from the interior of the processing vessel in a single-wafer substrate processing apparatus, or the like, frequently, or each time one wafer is processed, for igniting plasma for the purpose of cleaning the interior of the processing vessel. With this, the throughput of substrate processing is improved significantly. Further, similar advantage is achieved also in the single-wafer plasma etching apparatuses that carry out etching of a substrate to be processed one by one while using an NF3 gas.
Second Embodiment
In the experiment of
Referring to
Thus, the inventor of the present invention has discovered, with the investigation that constitutes the foundation of the present invention, that plasma ignition is still possible with a toroidal plasma generator such as the one shown in
On the other hand, the pressure or gas flow rate used in actual CVD apparatuses such as the CVD apparatus 10 of
Thus, in the investigation that constitutes the foundation of the present invention, the inventor of the present invention has verified whether or not the plasma is sustained from an ignition point (1) corresponding to the ignition point explained in
In the experiment of
Referring to
When the flow rate of the Ar/NF3 mixed gas is increased gradually to a predetermined processing flow rate corresponding to the process point (2), the pressure inside the processing vessel 11, and hence the total pressure in the gas passage 61 is increased, and a point (5) is reached. From this point, the conductance valve 13B is closed gradually while maintaining the flow rate of the Ar/NF3 mixed gas, and the pressure inside the processing vessel 11, and hence the pressure inside the gas passage 61, increases gradually to the process point (2).
In the case of a path B of
Further, with the path B, the flow rate of the Ar/NF3 mixed gas is increased while maintaining the fully closed state of the conductance valve 13B. With this, the pressure inside the processing vessel 11, and hence the total pressure in the gas passage 61, is increased gradually, and a point (7) corresponding to the process pressure of the point (2) is reached. Further, the flow rate of the Ar/NF3 mixed gas is increased gradually from the point (7) to the process point (2). Thereby, the conductance valve 13B is gradually closed and the pressure inside the processing vessel 11, and hence the total pressure in the gas passage 61, is maintained to the foregoing process pressure.
In a path C of
Thus, as a result of the experiments thus conducted for changing the gas flow rate and the total pressure from the ignition pint (1) to the process point (2) along various paths, it was confirmed that the ignited plasma is not extinguished even when the total pressure and the gas flow rate are changed, as long as the condition falls in the region surrounded by the foregoing points (1)-(7) in
As already explained, the points (4) and (6), and hence the path from the point (4) to the point (5), and from the point (6) to the pint (7), are determined by the designing of the conductance valve 13B of the CVD apparatus and the power of the vacuum pump 13, and thus, the path from the point (4) to the point (5) shifts in the direction toward increased flow rate when the maximum conductance of the conductance valve 13B is increased or the power of the vacuum pump 13 is increased. Further, the path from the point (6) to the point (7) moves toward the side of higher pressure when the minimum conductance of the conductance valve 13B is decreased or the power of the vacuum pump 13 is decreased.
Thus, the process point (2) can be set to any of the conditions explained previously with reference to
Thus, it is possible to achieve the cleaning rate of 2000 nm per minute for a thermal oxide film by increasing the NF3 concentration in the Ar/NF3 mixed gas to 80% at the process point (2) as shown in
Once the condition has reached the process point (2), it is possible to conduct ordinary cleaning process. In the CVD apparatus 10 of
As explained previously, the mixing ratio of the Ar gas and the NF3 gas in the Ar/NF3 mixed gas may be fixed or may be changed when moving from the ignition point (1) to the process point (2) in
Further, with the CVD apparatus 10 of
Further, With the present embodiment, it is also possible to provide mass flow controllers 16a and 16b of different capacities to the NF3 gas source as shown in
Thus, consider the case of increasing the flow rate of the Ar/NF3 mixed gas first from the ignition point (1) of
Further, the point (10) after the recovery is not limited to the location on the path C but can be chosen arbitrarily in the foregoing plasma sustaining area, as long as the flow rate is larger than the point (8).
Similar increase of pressure in the plasma generator to a high pressure corresponding to the process condition while sustaining the plasma ignited under low pressure is not limited to the case of using the Ar/NF3 gas but is also applicable to the case of using the Ar/F2 gas.
In this case, too, the F2 concentration in the Ar/F2 mixed gas may be maintained constant or changed.
Further, the rare gas supplied to the plasma generator is not limited to the Ar gas but gas of any of He, Ne, Kr, Xe, or the like, may be used.
Referring to
After ignition of plasma, the flow rate of the Ar gas and the NF3 gas is increased along an arbitrary path inside the region surrounded by the points (1)-(7) of
As explained previously, the cleaning process or etching process using NF3 is already started immediately after the plasma ignition.
In the present embodiment, too, it is possible to use a F2 gas in place of the NF3 gas. In this case, the pressure P1 for the ignition process and the flow rates of the Ar gas and the F2 gas have to be set so as to fall in the ignition range explained with reference to
It should be noted that the foregoing relationship of
Thus, with the present embodiment, plasma ignition is made in a mixed gas of a rare gas and a gas containing the halogen compound, when using any of the plasma generators 20-70 shown in
With the present embodiment, ignition of the plasma occurs at low voltage, and there arises no problem that a high voltage is applied to the electrodes or coils of the plasma generator. Thus, damaging of the high-frequency power source, electrodes or coils does not occur even when there is caused a large impedance change with the plasma ignition.
As explained before, with the plasma cleaning process or plasma etching process, the efficiency of the process is improved when the concentration or partial pressure of the cleaning gas or etching gas such as NF3 or F2 is large. While it is true that cleaning process or etching process is started with ignition of the plasma also in the ignition region of
Thus, with the present embodiment, the total pressure of the mixed gas of the rare gas and the cleaning or etching gas is gradually increased to a desired processing pressure after ignition of the plasma according to a sequence similar to the one shown in
In the sequence of
As explained, the points (4) and (6), and thus the path from the point (4) to the point (5), and the path from the point (6) to the point (7), are determined by the designing of the conductance valve 13B of the CVD apparatus used and the capacity of the vacuum pump 13, and thus, the path from the point (4) to the point (5) is shifted to the side of large flow rate when the maximum conductance of the conductance valve 13B is increased or the capacity of the vacuum pump 13 is increased. Further, the path from the point (6) to the point (7) is shifted to the high pressure side when the minimum conductance of the conductance valve 13B is decreased or the capacity of the vacuum pump 13 is decreased.
Further, the process point (2) can be set to any of the known conditions that provide efficient plasma cleaning.
Thus, it is possible to achieve a cleaning rate of about 2000 nm per minute for the thermal oxide film by increasing the NF3 concentration in the Ar/NF3 mixed gas to 80% in the process point (2). In this case, it is necessary to change the NF3 concentration in the Ar/FN3 mixed gas from the ignition point (1) to the process point (2), wherein it is confirmed that the plasma is sustained once it is ignited.
After the processing point (2) has been reached, it is possible to conduct ordinary cleaning process. In the CVD apparatus 10 of
In
Further, with the CVD apparatus 10 of
Further, similarly to the previous embodiment, it is possible with the present embodiment to provide plural mass flow controllers 16a and 16b of different capacities to the NF3 gas source 16A as shown in
Thus, consider the case of increasing the flow rate of the Ar/NF3 mixed gas starting from the ignition point (1) of
Further, the recovered point (10) is not limited to be located on the path C but can be located at any point in the foregoing plasma sustaining region as long as the flow rate is larger than the point (8).
Further, while the present invention has been explained for the case of forming plasma by supplying an Ar/NF3 mixed gas or an Ar/F2 mixed gas to the toroidal plasma generator, the plasma generator of the present invention is not limited to a toroidal plasma generator but it applicable to any other plasma generators shown in
Further, the diluting gas supplied for plasma formation is not limited to Ar, and the present invention holds even in the case a rare gas such as He, Ne, Kr, Xe, and the like is used, or in the case H2O, O2, H2, N2, C2F6, and the like, is used. Further, the cleaning/etching gas used with the present invention is not limited to NF3 or F2, but it is possible to use other halogen compound gas or a compound containing the CH3COO group such as CH3COOH.
While the present invention has been explained for preferred embodiments, the present invention is not limited to such specific embodiments and various variations and modifications may be made within the scope as set forth in the claims.
Claims
1. A method of generating plasma in a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil wound around a part of the gas passage,
- characterized in that said method comprises the steps of supplying a mixed gas of an Ar gas and an NF3 gas containing at least 5% of said NF3 gas, and igniting plasma by driving said coil with a high-frequency power,
- said step of igniting plasma being conducted under a total pressure of 6.65-66.5 Pa.
2. The method of generating plasma as claimed in claim 1, characterized in that said mixed gas contains NF3 by a concentration of 5% or more but not exceeding 45% in said plasma ignition step.
3. The method of generating plasma as claimed in claim 1, characterized in that said mixed gas in said plasma ignition step contains NF3 with a concentration of 10% or more but not exceeding 45% in said plasma ignition step.
4. The method of generating plasma as claimed in claim 1, characterized in that said mixed gas contains NF3 with a concentration of 20% or more but not exceeding 45% in said plasma ignition step.
5. The method of generating plasma as claimed in claim 1, characterized in that said method further comprises, after said step of igniting plasma, a step of increasing a total pressure of said mixed gas.
6. The method of generating plasma as claimed in claim 5, characterized in that said step of increasing said total pressure of said mixed gas is conducted while maintaining said concentration of NF3 in said mixed gas at constant.
7. The method of generating plasma as claimed in claim 5, characterized in that said step of increasing the total pressure of said mixed gas is conducted while changing said concentration of NF3 in said mixed gas.
8. The method of generating plasma as claimed in claim 5, characterized in that said mixed gas contains NF3, after said step of increasing said total pressure of said mixed gas, with a concentration of 5-40%.
9. The method of generating plasma as claimed in claim 1, characterized in that said mixed gas is supplied with a flow rate of 100SCCM or less in said plasma ignition step.
10. The method of generating plasma as claimed in claim 1, characterized in that said mixed gas is supplied with a flow rate of 3SCCM or more but not exceeding 80SCCM.
11. A method of generating plasma in a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil would around a part of said gas passage,
- characterized in that said method comprises the steps of supplying a mixed gas of an Ar gas and a F2 gas containing at least 5% of said F2 gas, and igniting plasma by driving said coil with a high-frequency power,
- said step of igniting plasma being conducted under a total pressure of 6.65-66.5 Pa.
12. The method of generating plasma as claimed in claim 11, characterized in that said mixed gas contains F2 with a concentration of 5% or more but not exceeding 45%.
13. The method of generating plasma as claimed in claim 11, characterized in that said method further comprises, after said ignition step, a step of increasing a total pressure of said mixed gas.
14. The method of generating plasma as claimed in claim 13, characterized in that said step of increasing said total pressure of said mixed gas is conducted while maintaining said concentration of F2 in said mixed gas at constant.
15. The method of generating plasma as claimed in claim 13, characterized in that said step of increasing said total pressure of said mixed gas is conducted while changing said concentration of F2 in said mixed gas.
16. The method of generating plasma as claimed in claim 11, characterized in that said mixed gas is supplied with a flow rate of 100SCCM or less in said plasma ignition step.
17. A cleaning method for cleaning a processing vessel evacuated by an evacuating system and coupled with a remote plasma source,
- said remote plasma source comprising a toroidal plasma generator, said toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet, said gas passage forming a circuitous path, and a coil would around a part of said gas passage,
- characterized in that said cleaning method comprises the steps of:
- forming radicals containing F in said remote plasma source; and
- supplying said radicals to an interior of said processing vessel and cleaning said interior of said processing vessel by said radicals,
- said step of forming said radicals comprising the steps of:
- supplying a mixed gas containing at least 5% of NF3 or F2 in an Ar gas to said gas passage as a cleaning gas with a first pressure in which plasma can ignite and igniting plasma by driving said coil by a high-frequency power; and
- increasing a total pressure of said mixed gas in said gas passage to a second pressure while maintaining said plasma,
- said cleaning step cleaning said interior of said processing vessel at said second pressure.
18. The cleaning method as claimed in claim 17, characterized in that said step of increasing said total pressure of said mixed gas comprises a step of changing a conductance of said evacuation system and a step of changing a flow rate of said mixed gas.
19. The cleaning method as claimed in claim 17, characterized in that said step of changing said total pressure of said mixed gas is conducted by changing a conductance of said evacuation system and a flow rate of said mixed gas simultaneously.
20. The cleaning method as claimed in claim 17, characterized in that said step of changing said total pressure of said mixed gas comprises a step of decreasing a conductance of said evacuation system while maintaining a flow rate of said mixed gas constant, and a step of increasing said flow rate of said mixed gas while maintaining said total pressure constant.
21. The cleaning method as claimed in claim 20, characterized in that said method further comprises a step of increasing said flow rate of said mixed gas while holding said conductance of said evacuation system maximum.
22. The cleaning method as claimed in claim 17, characterized in that said step of changing said total pressure of said mixed gas comprises a step of switching plural mass flow controllers.
23. The cleaning method as claimed in claim 17, characterized in that said step of increasing said total pressure of said mixed gas is conducted while maintaining said concentration of said cleaning gas in said mixed gas constant.
24. The cleaning method as claimed in claim 17, characterized in that said step of increasing said total pressure of said mixed gas is conducted while changing said concentration of said cleaning gas in said mixed gas.
25. The cleaning method as claimed in claim 17, characterized in that said cleaning step is conducted by setting said concentration of NF3 in said mixed gas to 50-40%.
26. The cleaning method as claimed in claim 17, characterized in that said mixed gas is supplied with a flow rate of 100SCCM or less in said plasma ignition step.
27. The cleaning method as claimed in claim 17, characterized in that said mixed gas contains NF3 as said cleaning gas and wherein said first pressure is set to 6.65-66.5 Pa.
28. The cleaning method as claimed in claim 27, characterized in that said mixed gas contains NF3, in said plasma ignition step, as said cleaning gas with a concentration of 5% or more but not exceeding 45%.
29. The cleaning method as claimed in claim 27, characterized in that said mixed gas contains NF3, in said plasma ignition step, as said cleaning gas with a concentration of 10% or more but not exceeding 45%.
30. The cleaning method as claimed in claim m 27, characterized in that said mixed gas contains NF3, in said plasma ignition step, with a concentration of 20% or more but note exceeding 45%.
31. The cleaning method as claimed in claim 17, characterized in that said mixed gas contains F2 as said cleaning gas, and wherein said first pressure is set to 6.65-66.5 Pa.
32. The cleaning method as claimed in claim 31, wherein said mixed gas contains F2, in said plasma ignition step, as said cleaning gas with a concentration of 5% or more but not exceeding 45%.
33. A substrate processing method in a processing vessel evacuated by an evacuation system and coupled with a remote plasma source,
- characterized in that said remote plasma source comprises a toroidal plasma generator comprising a gas passage having a gas entrance and a gas outlet and forming a circuitous path, and a coil would around a part of said gas passage,
- said substrate processing method comprising the steps of:
- forming radicals containing F in said remote plasma source; and
- etching a surface of a substrate to be processed in said processing vessel by said radicals by supplying said radicals to an interior of said processing vessel,
- said step of forming said radicals comprising the steps of:
- supplying a mixed gas containing NF3 or F2 in an Ar gas with a concentration of at least 5% to said gas passage under a first pressure in which ignition of plasma is possible and igniting plasma by driving said coil with a high-frequency power; and
- increasing a total pressure of said mixed gas in said passage to a second pressure while maintaining said plasma,
- said step of etching being conducted under said second pressure.
34. The substrate processing method as claimed in claim 33, characterized in that said step of increasing said total pressure of said mixed gas comprises a step of changing a conductance of said evacuation system and a step of changing a flow rate of said mixed gas.
35. The substrate processing method as claimed in claim 33, wherein said step of changing said total pressure of said mixed gas is conducted by changing a conductance of said evacuating system and a flow rate of said mixed gas simultaneously.
36. The substrate processing method as claimed in claim 33, characterized in that said step of changing said total pressure of said mixed gas comprises a step of decreasing a conductance of said evacuation system while maintaining a flow rate of said mixed gas constant, and a step of increasing said flow rate of said mixed gas while maintaining said total pressure constant.
37. The substrate processing method as claimed in claim 36, characterized in that said method further comprises a step of increasing said flow rate of said mixed gas while holding said conductance of said evacuation system maximum.
38. The substrate processing method as claimed in claim 33, characterized in that said step of changing said total pressure of said mixed gas comprises the step of switching plural mass flow controllers.
39. The substrate processing method as claimed in claim 33, characterized in that said step of increasing said total pressure of said mixed gas is conducted while maintaining said concentration of said etching gas in said mixed gas constant.
40. The substrate processing method as claimed in claim 33, characterized in that said step of increasing said total pressure of said mixed gas is conducted while changing said concentration of said etching gas in said mixed gas.
41. The substrate processing method as claimed in claim 33, characterized in that said etching step is conducted by setting said concentration of NF3 in said mixed gas to 50-40%.
42. The substrate processing method as claimed in claim 33, characterized in that said mixed gas is supplied in said plasma ignition step with a flow rate of 100SCCM or less.
43. The substrate processing method as claimed in claim 33, characterized in that said mixed gas contains NF3 as said etching gas, and wherein said first pressure is set to 6.65-66.5 Pa.
44. The substrate processing method as claimed in claim 43, characterized in that said mixed gas contains NF3 in said plasma ignition step as said etching gas with a concentration of 5% or more but not exceeding 45%.
45. The substrate processing method as claimed in claim 43, characterized in that said mixed gas contains NF3 as said etching gas in said plasma ignition step with a concentration of 10% or more but not exceeding 45%.
46. The substrate processing method as claimed in claim 43, characterized in that said mixed gas contains NF3 as said etching gas in said plasma ignition step with a concentration of 20% or more but not exceeding 45%.
47. The substrate processing method as claimed in claim 33, characterized in that said mixed gas contains F2 as said etching gas and wherein said first pressure is set to 6.65-66.5 Pa.
48. The substrate processing method as claimed in claim 47, characterized in that said mixed gas contains F2 as said etching gas in said plasma ignition step with a concentration of 5% or more but not exceeding 45%.
49. A cleaning method for cleaning an interior of a processing vessel by plasma-excited radicals of a cleaning gas under a first pressure zone, characterized in that said method comprises the steps of:
- introducing a mixed gas of a diluting gas and a cleaning gas to a plasma generator under a second pressure lower than said first pressure and igniting plasma; and
- increasing a pressure inside said processing vessel to said first pressure zone from said second pressure zone.
50. The cleaning method as claimed in claim 49, characterized in that said cleaning gas contains a halogen compound.
51. The cleaning method as claimed in claim 49, characterized in that said cleaning gas contains NF3.
52. The cleaning method as claimed in claim 49, characterized in that said cleaning gas contains F2.
53. The cleaning method as claimed in claim 49, characterized in that said diluting gas is selected from any of Ar, Kr and Xe.
54. The cleaning method as claimed in claim 49, characterized in that said plasma generator is a toroidal plasma generator.
55. The cleaning method as claimed in claim 49, characterized in that said plasma generator is any one of a capacitive-coupled plasma generator, an induction-coupled plasma generator, an ECR plasma generator, a helicon wave plasma generator, and a microwave cavity plasma generator.
56. A substrate processing method for etching a surface of a substrate to be processed by plasma-excited radicals under a first pressure zone, comprising the steps of:
- introducing a mixed gas of a diluting gas and an etching gas into a plasma generator under a second pressure lower than said first pressure and igniting plasma; and
- increasing a pressure inside said processing vessel to said first pressure zone from said second pressure zone.
57. The substrate processing method as claimed in claim 56, characterized in that said etching gas contains a halogen compound.
58. The substrate processing method as claimed in claim 56, characterized in that said etching gas contains NF3.
59. The substrate processing method as claimed in claim 56, characterized in that said etching gas contains F2.
60. The substrate processing method as claimed in claim 56, characterized in that said diluting gas is selected from any of Ar, Kr and Xe.
61. The substrate processing method as claimed in claim 56, characterized in that said plasma generator is a toroidal type plasma generator.
62. The substrate processing method as claimed in claim 56, characterized in that said plasma generator is any one of a capacitive-coupled plasma generator, an induction-coupled plasma generator, an ECR plasma generator, a helicon wave plasma generator, and a microwave cavity plasma generator.
63. A cleaning method for cleaning an interior of a processing vessel by plasma-excited radicals of a cleaning gas under a first pressure zone, comprising the steps of:
- introducing a mixed gas of a diluting gas and a cleaning gas into a plasma generator under a second flow rate zone smaller than said first flow rate zone and igniting plasma; and
- increasing a flow rate of said mixed gas from said first flow rate zone to said second flow rate zone.
64. The cleaning method as claimed in claim 63, characterized in that said cleaning gas contains a halogen compound.
65. The cleaning method as claimed in claim 63, characterized in that said cleaning gas contains NF3.
66. The cleaning method as claimed in claim 63, characterized in that said cleaning gas contains F2.
67. The cleaning method as claimed in claim 63, characterized in that said diluting gas is selected from any of Ar, Kr and Xe.
68. The cleaning method as claimed in claim 63, characterized in that said plasma generator is a toroidal plasma generator.
69. The cleaning method as claimed in claim 63, characterized in that said plasma generator is any one of a capacitive-coupled plasma generator, an induction-coupled plasma generator, an ECR plasma generator, a helicon wave plasma generator, and a microwave cavity plasma generator.
70. A substrate processing method for etching a surface of a substrate to be processed in a processing vessel by plasma-excited radicals of etching under a first flow rate zone, comprising the steps of:
- introducing a mixed gas of a diluting gas and an etching gas into a plasma generator under a second flow rate zone smaller than said first flow rate zone and igniting plasma; and
- increasing a flow rate of said mixed gas from said second flow rate zone to said first flow rate zone.
71. The substrate processing method as claimed in claim 70, characterized in that said cleaning gas contains a halogen compound.
72. The substrate processing method as claimed in claim 70, characterized in that said cleaning gas contains NF3.
73. The substrate processing method as claimed in claim 70, characterized in that said cleaning gas contains F2.
74. The substrate processing method as claimed in claim 70, characterized in that said diluting gas is selected from any of Ar, Kr and Xe.
75. The substrate processing method as claimed in claim 70, characterized in that said plasma generator is a toroidal plasma generator.
76. The substrate processing method as claimed in claim 70, characterized in that said plasma generator is any one of a capacitive-coupled plasma generator, an induction-coupled plasma generator, an ECR plasma generator, a helicon wave plasma generator, and a microwave cavity plasma generator.
Type: Application
Filed: Jun 25, 2004
Publication Date: Oct 12, 2006
Applicant: TOKYO ELECTRON LIMITED (Tokyo)
Inventors: Hiroshi Kannan (Tokyo), Noboru Tamura (Yamanashi), Kazuya Dobashi (Tokyo)
Application Number: 10/562,400
International Classification: B08B 6/00 (20060101); C23F 1/00 (20060101);