CHEMICAL MECHANICAL POLISHING APPARATUS

Abstract

The present disclosure discloses a chemical mechanical polishing apparatus including a polishing machine platform, an electrode film, a polishing pad and a wafer carrier. The electrode film has a first single electrode structure and is disposed on the polishing machine platform. The polishing pad is disposed on the electrode film. The wafer carrier is disposed on the polishing machine platform. In particular, the first single electrode structure generates a first homopolar electric field on the polishing pad.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a chemical mechanical polishing apparatus; in particular, the invention relates to a chemical mechanical polishing apparatus using electrode film to generate an electric field.

2. Description of Related Art

A chemical mechanical polishing apparatus is widely used in flattening a semiconductor wafer. The chemical mechanical polishing apparatus mounts the wafer on the polishing pad, and polishes and flattens the wafer surface by applying a slurry and exerting a force thereon.

Conventional slurries include abrasive powders, PH buffers, antioxidants, inhibitors, and various chemical surfactants. These chemical materials interact with the surface of the wafer and form a removable oxide layer or passivation layer.

The PH buffers in conventional slurries adjust the electrical repulsive force between the abrasive powder particles by changing the level of acidity and alkaline (i.e., the chargeability of slurry), thus maintaining the stability of the suspension of the powder particles. However, the effect of the PH buffers is limited so that the efficiency of polishing is decreased and that scratches and residual stresses remain on the surface of wafer.

Therefore, improving the polishing efficiency by modifying the structural design of conventional chemical mechanical polishing apparatus is crucial in the field of semiconductor manufacturing.

SUMMARY OF THE INVENTION

The object of the present disclosure is to improve the polishing efficiency of conventional chemical mechanical polishing apparatus.

In order to achieve the aforementioned objects, according to an embodiment of the present disclosure, a chemical mechanical polishing apparatus includes a polishing machine platform, an electrode film, a polishing pad and a wafer carrier. The electrode film has a first single electrode structure and is disposed on the polishing machine platform. The polishing pad is disposed on the electrode film. The wafer carrier is disposed on the polishing machine platform. In particular, the first single electrode structure generates a first homopolar electric field on the polishing pad.

In order to achieve the aforementioned objects, according to another embodiment of the present disclosure, a chemical mechanical polishing apparatus includes a polishing machine platform, a polishing pad, a wafer carrier and an electrode film. The polishing pad is disposed on the electrode film. The wafer carrier is disposed on the polishing machine platform and has a mounting surface for mounting a wafer. The electrode film has a first single electrode structure and is disposed on the mounting surface of the wafer carrier. In particular, the first single electrode structure generates a first homopolar electric field on the polishing pad.

The advantage of the present disclosure includes:

The chemical mechanical polishing apparatus in the present disclosure generates an electric field between the wafer and the polishing pad by the technical feature that “the first single electrode structure generates a first homopolar electric field on the polishing pad”. This technical feature keeps the slurry (and the abrasive powder particles) in the polishing pad, and increases the probability of contact between the wafer and the abrasive powder particles. Therefore, the overall polishing efficiency is increased.

In order to further the understanding regarding the present disclosure, the following embodiments are provided along with illustrations to facilitate the disclosure of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic 3-dimensional view of a chemical mechanical polishing apparatus according to a first embodiment of the present disclosure;

FIG. 2 shows a schematic diagram of a chemical mechanical polishing apparatus according to the first embodiment of the present disclosure;

FIG. 3 shows a schematic cross-sectional view taken along the plane III-III in FIG. 2;

FIG. 4 shows another schematic cross-sectional view along the plane III-III in FIG. 2;

FIG. 5 shows a schematic exploded view of a chemical mechanical polishing apparatus according to a second embodiment of the present disclosure;

FIG. 6 shows a schematic diagram of a chemical mechanical polishing apparatus according to the second embodiment of the present disclosure;

FIG. 7 shows a schematic cross-sectional view taken along the plane VII-VII in FIG. 6 when the first single electrode structure generates a positive electric field and the second electrode structure generates a negative electric field between the wafer and the polishing pad;

FIG. 8 shows a schematic cross-sectional view along the plane VII-VII in FIG. 6 when the first single electrode structure generates a negative electric field and the second electrode structure generates a positive electric field between the wafer and the polishing pad;

FIG. 9 shows a schematic diagram of a first embodiment of the first single electrode structure;

FIG. 10 shows a schematic diagram of a second embodiment of the first single electrode structure;

FIG. 11 shows a schematic diagram of a third embodiment of the first single electrode structure;

FIG. 12 shows a schematic cross-sectional view taken along the plane XII-XII in FIG. 9;

FIG. 13 shows a schematic diagram of a fourth embodiment of the first single electrode structure;

FIG. 14 shows a schematic lateral view of a fourth embodiment of the first single electrode structure;

FIG. 15 shows a schematic 3-dimensional view of a chemical mechanical polishing apparatus according to a third embodiment of the present disclosure;

FIG. 16 shows a schematic diagram of a first embodiment of an electric field enhancement structure; and

FIGS. 17A to 17G are schematic diagrams of a conductor of the electric field enhancement structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The aforementioned illustrations and following detailed descriptions are exemplary for the purpose of further explaining the scope of the present disclosure. Other objectives and advantages related to the present disclosure will be illustrated in the subsequent descriptions and appended drawings.

It should be noted that the present embodiments use first, second, third and so forth to distinguish one element from another, but the present disclosure is not limited thereto. In addition, the term “or” in the present disclosure may include any listed items and any combinations thereof, depending on the context

First Embodiment

FIG. 1 shows a schematic 3-dimensional view of a chemical mechanical polishing apparatus according to a first embodiment of the present disclosure. The chemical mechanical polishing apparatus Z in the present embodiment includes a polishing machine platform 1, an electrode film 2, a polishing pad 3 and a wafer carrier 4. The electrode film 2 has a first single electrode structure 21 and is disposed on the polishing machine platform 1. The polishing pad 3 is disposed on the electrode film 2. The wafer carrier 4 is disposed on the polishing machine platform 1. In particular, the first single electrode structure 21 generates a first homopolar electric field on the polishing pad 3 after receiving an operating voltage.

In practice, a sprinkler head 5 of the chemical mechanical polishing apparatus Z continuously supplies slurry to the polishing pad 3. That is, the slurry is distributed in the space between the polishing pad 3 and a wafer 6. Therefore, the first homopolar electric field (positive or negative) is generated between the polishing pad 3 and the wafer 6 when the first single electrode structure 21 of the electrode film 2 is electrically coupled with a single electrode wire (positive electrode wire or negative electrode wire). The first homopolar electric field interacts with the abrasive powder particles of the slurry and changes the charge distribution of the abrasive powder particles, thus increasing the uniformity of the polishing process.

The electrode film 2 in the first embodiment could be disposed on a bottom surface 31 of the polishing pad 3. The electrode film 2 could be disposed on a top surface 11 of the polishing machine platform 1 as well. It is also possible that the electrode film 2 is disposed within the polishing machine platform 1. The present disclosure does not intend to limit the location of the electrode film 2, and a person having ordinary skill in the art may modify the location thereof to fit particular needs. It should be noted that the electrode film 2 could be completely attached to, partially attached to, or placed on the targeted surface.

In addition, the electrode film 2 could also be disposed on a mounting surface of the wafer carrier 4 so that the electrode film 2 generates the first homopolar electric field on the polishing pad 3. The electrode film 2 may also be disposed between the wafer carrier 4 and the wafer 6.

FIG. 2 shows a schematic diagram of a chemical mechanical polishing apparatus according to the first embodiment of the present disclosure. In operation, the sprinkler head 5 of the chemical mechanical polishing apparatus Z continuously supplies slurry to the polishing pad 3, which the wafer 6 directly contacts. At this time, the first single electrode structure 21 receives an operating voltage and generates the first homopolar electric field to act on the abrasive powder particles. Therefore, the polishing pad 3 uniformly polishes the wafer 6 as the wafer carrier 4 spins.

FIG. 3 shows a schematic cross-sectional view taken along the III-plane III in FIG. 2. As shown in FIG. 3, the first single electrode structure 21 is electrically coupled with the positive electrode wire and generates a positive electric field when the slurry L is positively charged. In this case, the electrical repulsive force moves the abrasive powder particles toward the wafer 6 so that a material remote rate (MRR) is increased. On the other hand, the first single electrode structure 21 could be electrically coupled with the negative electrode wire and generate a negative electric field when the slurry L is positively charged. In this case, the electrical attractive force moves the abrasive powder particles toward the polishing pad 3 so that the wafer 6 can be evenly flattened.

FIG. 4 shows another schematic cross-sectional view along the III-III plane in FIG. 2. As shown in FIG. 4, the first single electrode structure 21 is electrically coupled with the negative electrode wire and generates a negative electric field when the slurry L is negatively charged. In this case, the electrical repulsive force moves the abrasive powder particles toward the wafer 6 so that a material remote rate (MRR) is increased. On the other hand, the first single electrode structure 21 could be electrically coupled with the positive electrode wire and generate a positive electric field when the slurry L is negatively charged. In this case, the electrical attractive force moves the abrasive powder particles toward the polishing pad 3 so that the wafer 6 can be evenly flattened.

In the present embodiment, as the first single electrode structure 21 is electrically coupled with one of the electrode wires (positive or negative), the uncoupled electrode wire could connect to any position of a power supply (not shown) or the polishing machine platform 1 (not shown), but the present disclosure is not limited thereto. For example, the uncoupled electrode wire could be disposed on the wafer carrier 4, as described in the following embodiment.

Second Embodiment

FIG. 5 shows a schematic exploded view of a chemical mechanical polishing apparatus according to a second embodiment of the present disclosure. The chemical mechanical polishing apparatus Z′ in the present embodiment includes a polishing machine platform 1′, a first electrode film 2′, a polishing pad 3′ and a wafer carrier 4′. The chemical mechanical polishing apparatus Z′ in the present embodiment basically has the same structure as the previous (first) embodiment, and the first electrode film 2′ in the present embodiment is basically the same as the electrode film 2 in the previous embodiment. The following descriptions focus on the differences between the present and previous embodiments.

Referring to FIG. 5, unlike the chemical mechanical polishing apparatus Z in FIG. 1, the present embodiment further includes a second electrode film 7′ disposed between the wafer carrier 4′ and a wafer 6′. That is, the second electrode film 7′ is disposed on a mounting surface 41′ of the wafer carrier 4′. Specifically, the second electrode film 7′ includes a second electrode structure 71′ so that it can be disposed on the mounting surface 41′ of the wafer carrier 4′. In addition, the structure of the first electrode film 2′ and the second electrode film 7′ could be the same or different. The following descriptions detail the structure of the electrode films and related modifications.

The first single electrode structure 21′ could be electrically coupled with a first single electrode wire (positive wire or negative wire) to generate a first homopolar electric field on the polishing pad 3′, and the second electrode structure 71′ could be electrically coupled with a second single electrode wire (negative wire or positive wire) to generate a second homopolar electric field on the polishing pad 3′. It should be noted that the first homopolar electric field has a polarity different from the second homopolar electric field.

For example, the first single electrode structure 21′ of the first electrode film 2′ could be electrically coupled with a positive first single electrode wire to generate a positive first homopolar electric field, or could be electrically coupled with a negative first single electrode wire to generate a negative first homopolar electric field. Similarly, the second electrode structure 71′ of the second electrode film 7′ could be electrically coupled with a positive second electrode wire to generate a positive second homopolar electric field, or could be electrically coupled with a negative second electrode wire to generate a negative second homopolar electric field. It is also possible that one of the first single electrode structure 21′ and the second electrode structure 71′ generates a homopolar electric field while the other generates no electric field. A person having ordinary skill in the art may modify the setting of the first single electrode structure 21′ and the second electrode structure 71′ to fit particular needs.

FIG. 6 shows a schematic diagram of a chemical mechanical polishing apparatus according to the second embodiment of the present disclosure. In practice, a sprinkler head 5′ of the chemical mechanical polishing apparatus Z′ continuously supplies slurry to the polishing pad 3′. At the same time, the first single electrode structure 21′ and the second electrode structure 71′ receive an operating voltage, and generate the first and second homopolar electric fields with different polarities to act on the abrasive powder particles of the slurry. Therefore, the polishing pad 3′ uniformly polishes the wafer 6′ as the wafer carrier 4′ spins.

FIG. 7 shows a schematic cross-sectional view taken along the plane VII-VII in FIG. 6 when the first single electrode structure 21′ generates a positive homopolar electric field and the second electrode structure 71′ generates a negative homopolar electric field between the wafer and the polishing pad. FIG. 8 shows a schematic cross-sectional view taken along the plane VII-VII in FIG. 6 when the first single electrode structure 21′ generates a negative electric field and the second electrode structure 71′ generates a positive electric field between the wafer and the polishing pad. Referring to FIG. 7, the first single electrode structure 21′ generates a positive electric field between the polishing pad 3′ and the wafer 6′ when being electrically coupled with the positive electrode wire, and the second electrode structure 71′ generates a negative electric field between the polishing pad 3′ and the wafer 6′ when being electrically coupled with the negative electrode wire. Referring to FIG. 8, the first single electrode structure 21′ generates a negative electric field between the polishing pad 3′ and the wafer 6′ when being electrically coupled with the negative electrode wire, and the second electrode structure 71′ generates a positive electric field between the polishing pad 3′ and the wafer 6′ when being electrically coupled with the positive electrode wire.

Specifically, the electric fields with opposite polarities generated by the first single electrode structures 21′ and the second electrode structure 71′ change the charge distribution of the abrasive powder particles, and thus affect the efficiency of polishing. Referring to FIG. 7, for example, the abrasive powder particles are repelled by the positive electric field generated by the first single electrode structure 21′ and attracted by the negative electric field generated by the second electrode structure 71′. Referring to FIG. 8, on the other hand, the abrasive powder particles are attracted by the negative electric field generated by the first single electrode structure 21′ and repelled by the positive electric field generated by the second electrode structure 71′.

It should be noted that the first single electrode structure 21′ and the second electrode structure 71′ in the present embodiment generate electric fields with opposite polarities to act on the abrasive powder particles concurrently. In other embodiments of the present disclosure, it is possible to generate only one electric field according to the polarity of the abrasive powder particles. For example, the first single electrode structure 21′ generates a positive (or negative) electric field, and the second electrode structure 71′ generates no electric field, and vice versa. A person having ordinary skill in the art could alter the electric fields generated by the first electrode film 2′ and the second electrode film 7′ to fit particular needs.

FIG. 9 shows a schematic diagram of a first embodiment of the first single electrode structure. FIG. 10 shows a schematic diagram of a second embodiment of the first single electrode structure. The electrode film 2 could be circular, and cover smoothly and completely on the polishing machine platform. The first single electrode structure 21 is formed by a coplanar metal conductor. The first single electrode structure 21 could include a plurality of metal wires that are coplanar and separated from each other.

Referring to FIG. 9, the first single electrode structure 21a is a planar swirl metal wire having a constant distance between neighboring arcs, thereby providing a stable electric field. Referring to FIG. 10, the first single electrode structure 21b is a planar labyrinth-like metal wire, which includes a plurality of flat portions 211b and bent portions 212b. The plurality of flat portions 211b have a constant interval therebetween, thereby providing a stable electric field. In addition, the plurality of bent portions 212b could be rectangular, semi-circular, arc-shaped, and so forth.

FIG. 11 shows a schematic diagram of a third embodiment of the first single electrode structure. The first single electrode structure 21c is a flat metal layer formed by processes including CVD, PVD, coating and printing. The flat metal layer could be composed of single metal, or be composed of multiple metals selected from copper, silver, nickel, titanium, titanium nitride, tantalum, tantalum nitride, aluminum, tungsten, tungsten nitride, silicon tungsten, titanium silicon nitride, silicon nitride, tantalum. The flat metal layer could include a single layer, or multiple layers. However, the material and structure of the first single electrode structure 21c are not limited to that disclosed in the exemplary embodiments.

Further referring to FIG. 5, the first electrode film 2′ and the second electrode film 7′ in the second embodiment could have the same structure, or different structures. For example, both the first single electrode structure 21′ and the second electrode structure 71′ could include a plurality of metal wires. It is also possible that the first single electrode structure 21′ includes a plurality of metal wires and the second electrode structure 71′ is a flat metal layer. A person having ordinary skill in the art may modify the design of the first single electrode structure 21′ and the second electrode structure 71′ to fit particular needs as long as two electrode structures together could generate an electric field.

FIG. 12 shows a schematic cross-sectional view taken along the plane XII-XII in FIG. 9. The electrode film 2 includes a first single electrode structure 21, a base layer 22 and a protective layer 23. Specifically, the first single electrode structure 21 is disposed on the base layer 22 and covered by the protective layer 23. The first single electrode structure 21 is protected by the protective layer 23 from damage when being attached to the polishing pad 3. In addition, the protective layer 23 could be a non-conductive glue attached to the bottom surface of the polishing pad so that the electrode film 2 could attach to the polishing pad 3 without additional adhesive. It should be noted that the protective layer 23 could be selected from substrate single-sided adhesive, substrate-free single-sided adhesive, substrate double-sided adhesive, substrate-free double-sided adhesive, light-curing adhesive, heat-curing adhesive, light curing adhesive or light-heat curing adhesive. The light curing adhesive could be an acrylic-based UV-curable adhesive gel, and the heat-curing adhesive could be an epoxy resin, polyimide resin or silicon resin. However, the material of the protective layer 23 in the present disclosure is not limited thereto.

A person having ordinary skill in the art should understand that the aforementioned types of chemical mechanical polishing apparatus are exemplary embodiments, and could be modified to fit particular needs.

For example, referring to FIG. 13, which shows a schematic diagram of a fourth embodiment of the first single electrode structure 21. The first single electrode structure 21d includes a first single electrode wire (positive wire or negative wire), which further includes a first electrode wire 211d and a second electrode wire 212d staggered to each other. Referring to FIG. 14, which shows a schematic lateral view of a fourth embodiment of the first single electrode structure 21. The height of the first electrode wire 211d relative to the base layer 22 is different from the height of the second electrode 212d wire relative to the base layer 22. That is, the first electrode wire 211d could be higher than the second electrode wire 212d in its entirety, or the first electrode wire 211d could be partially higher than the second electrode wire 212d. A person having ordinary skill in the art may modify the height of the first electrode wire 211d and the second electrode wire 212d to fit particular needs as long as the two wires are staggered to each other.

In other embodiments of the present disclosure, the chemical mechanical polishing apparatus could further include an electric field enhancement structure to enhance the electric field generated on the electric film. The following embodiment describes the electric field enhancement structure in detail. In addition, the electric field enhancement structure could be disposed between the electrode film and the wafer when the electrode film is set between the wafer carrier and the wafer. That is, the electric field enhancement structure aims to help the electrode film increase the strength of the electric field.

Third Exemplary Embodiment

Referring to FIG. 15, which shows a schematic 3-dimensional view of a chemical mechanical polishing apparatus according to a third embodiment of the present disclosure. The chemical mechanical polishing apparatus Z″ includes a polishing machine platform 1″, a first electrode film 2″, a polishing pad 3″ and a wafer carrier 4″. The chemical mechanical polishing apparatus Z″ in the present embodiment basically has the same structure as the first embodiment, and the first electrode film 2″ in the present embodiment is basically the same as the electrode film 2 in the previous embodiment. The following descriptions focus on the differences between the present and previous embodiments.

Referring further to FIG. 15, the difference between the chemical mechanical polishing apparatus Z″ in the present embodiment and previous embodiments resides in the electric field enhancement structure 8″, which is disposed on the first electrode film 2″. Specifically, the electric field enhancement structure 8″ is disposed between the first electrode film 2″ and the polishing pad 3″, and includes a plurality of conductors 81″ that are adjacent to each other. The plurality of conductors 81″ could be a floating wire structure. In addition, the plurality of conductors 81″ could have the same structure, or have different structures.

Referring to FIGS. 17A to 17G, which are schematic diagrams of a conductor of the electric field enhancement structure. The plurality of conductors 81″ could have different structures, such as having two opposite ends separated from each other. That is, each of the plurality of conductors 81″ has two opposite ends separated from each other, which form an opening. Referring to FIG. 17A, the plurality of conductors 81″ are U-shaped. Referring to FIG. 17B, the plurality of conductors 81″ are C-shaped. Referring to FIG. 17C, the plurality of conductors 81″ are rectangular with an opening at one side. Referring to 17D, four L-shaped conductors 81″ form a near-rectangular shape having multiple openings. Referring to Figs. E to F, multiple conductors 81″ form a group, and each conductor 81″ has two opposite ends separated from each other. Referring to FIG. 17E, the conductors 81″ are cylindrical. Referring to FIG. 17F, the conductors 81″ are square columnar. Referring to 17G, the conductors 81″ are conical.

Effects of Exemplary Embodiments

The chemical mechanical polishing apparatus in the present disclosure generates a single electric field between the wafer and the polishing pad by the technical feature that “the first single electrode structure generates a first homopolar electric field on the polishing pad”. This technical feature keeps the slurry (and the abrasive powder particles) in the polishing pad, or increases the probability of contact between the wafer and the abrasive powder particles. Therefore, the overall polishing efficiency is increased.

The descriptions illustrated supra set forth simply the preferred embodiments of the present disclosure; however, the characteristics of the present disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the present disclosure delineated by the following claims.

Claims

1. A chemical mechanical polishing apparatus, comprising:

a polishing machine platform;

an electrode film having a first single electrode structure and being disposed on the polishing machine platform;

a polishing pad disposed on the electrode film; and

a wafer carrier disposed on the polishing machine platform;

wherein the first single electrode structure generates a first homopolar electric field on the polishing pad.

2. The chemical mechanical polishing apparatus according to claim 1, further comprising a second electrode structure disposed on the polishing pad, the location of the second electrode structure corresponding to the location of the electrode film.

3. The chemical mechanical polishing apparatus according to claim 2, wherein the wafer carrier has a mounting surface for mounting a wafer, and a second electrode structure is disposed on the mounting surface.

4. The chemical mechanical polishing apparatus according to claim 2, wherein the second electrode structure generates a second homopolar electric field on the polishing pad; wherein the first homopolar electric field has a polarity different from the second homopolar electric field.

5. The chemical mechanical polishing apparatus according to claim 1, wherein the electrode film is disposed on a bottom surface of the polishing pad.

6. The chemical mechanical polishing apparatus according to claim 1, wherein the electrode film is disposed on the top surface of the polishing machine platform.

7. The chemical mechanical polishing apparatus according to claim 1, wherein the electrode film is disposed within the polishing machine platform.

8. The chemical mechanical polishing apparatus according to claim 1, wherein the electrode film further includes a base layer and a protective layer, the first single electrode structure being disposed on the base layer and being covered by the protective layer.

9. The chemical mechanical polishing apparatus according to claim 8, wherein the protective layer is a nonconductive glue attached to the bottom surface of the polishing pad.

10. The chemical mechanical polishing apparatus according to claim 8, wherein the first single electrode structure includes a first electrode wire and a second electrode wire staggered to each other, the height of the first electrode wire relative to the base layer being different from the height of the second electrode wire relative to the base layer.

11. The chemical mechanical polishing apparatus according to claim 1, wherein the first single electrode structure is a flat metal layer.

12. The chemical mechanical polishing apparatus according to claim 1, wherein the first single electrode structure includes a plurality of metal wires that are coplanar and separated from each other.

13. The chemical mechanical polishing apparatus according to claim 1, wherein the electrode film is circular and covers smoothly and completely on the polishing machine platform, and the first single electrode structure is formed by a coplanar metal conductor.

14. The chemical mechanical polishing apparatus according to claim 1, further including an electric field enhancement structure being disposed on the electrode film and having a plurality of conductors that are adjacent to each other.

15. The chemical mechanical polishing apparatus according to claim 14, wherein each of the plurality of conductors has two opposite ends separated from each other.

16. A chemical mechanical polishing apparatus, comprising:

a polishing machine platform;

a polishing pad disposed on the electrode film;

a wafer carrier disposed on the polishing machine platform and having a mounting surface for mounting a wafer; and

an electrode film having a first single electrode structure and being disposed on the mounting surface of the wafer carrier;

wherein the first single electrode structure generates a first homopolar electric field on the polishing pad.

17. The chemical mechanical polishing apparatus according to claim 16, further including an electric field enhancement structure being disposed under the electrode film and having a plurality of conductors that are adjacent to each other.