US20150050866A1

US20150050866A1 - Polishing pad, polishing apparatus and method for manufacturing polishing pad

Info

Publication number: US20150050866A1
Application number: US14/456,237
Authority: US
Inventors: Chung-Chih Feng; I-Peng Yao; Yung-Chang Hung; Wen-Chieh Wu
Original assignee: San Fang Chemical Industry Co Ltd
Current assignee: San Fang Chemical Industry Co Ltd
Priority date: 2013-08-16
Filing date: 2014-08-11
Publication date: 2015-02-19
Also published as: TW201507813A; TWI590918B

Abstract

The present invention relates to a polishing pad comprising a foaming resin frame and a plurality of auxiliary fiber filaments, and each of the auxiliary fiber filaments is independent and dispersed randomly in the foaming resin frame. The invention also relates to a polishing apparatus and a method for manufacturing the polishing pad.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a polishing pad, a polishing apparatus, and a method for manufacturing the polishing pad.
2. Description of the Related Art
Polishing generally refers to a wear control for a preliminary coarse surface in a process of chemical mechanical polishing (CMP), which makes the slurry containing fine particles evenly dispersed on the upper surface of a polishing pad, and at the same time places a substrate against the polishing pad and then rubs the substrate repeatedly with a regular motion. The substrate may be objects such as a semiconductor, a storage medium substrate, an integrated circuit, an LCD flat-panel glass, an optical glass and a photoelectric panel. During the polishing process, a polishing pad must be used for polishing the substrate, and the quality of the polishing pad directly influences the polishing effect of the substrate.
FIG. 1 shows a schematic view of a polishing apparatus with a conventional polishing pad. The polishing apparatus 1 includes a lower base plate 11, a mounting sheet 12, a substrate 13, an upper base plate 14, a polishing pad 15 and slurry 16. The lower base plate 11 is positioned opposite to the upper base plate 14. The mounting sheet 12 is adhered to the lower base plate 11 through an adhesive layer (not shown) and is used for carrying and mounting the substrate 13. The polishing pad 15 is mounted on the upper base plate 14, and faces to the lower base plate 11 for polishing the substrate 13.
The operation mode of the polishing apparatus 1 is as follows. First, the substrate 13 is mounted on the mounting sheet 12, and then both the upper and lower base plates 14 and 11 are rotated and the lower base plate 11 is simultaneously moved downward, such that the polishing pad 15 contacts the surface of the substrate 13, and a polishing operation for the substrate 13 may be performed by continuously supplementing the slurry 16 and using the effect of the polishing pad 15.
FIG. 2 shows a sectional view of a first conventional polishing pad. The polishing pad 25 is a non-woven-fabric-type polishing pad comprising a plurality of fiber filaments 251 and a resin 252. A method for manufacturing the polishing pad 25 is using a composite material including the velvet or suede-like fiber filaments 251 and the resin 252. The fiber filaments 251 are manufactured by a non-woven producing method such as needle felting, cotton carding or cotton folding, and the produced fiber filaments are intertwined with each other. Then, a non-woven fabrics formed by the fiber filaments 251 are immersed in a thermoplastic polyurethane resin 252 to form a softer thin slice having high compressed transformation by wet solidification. However, due to the softness of the non-woven-fabric-type polishing pad 25, the planarization of a polishing surface is poor. Furthermore, the hardness of the polishing pad 25 is not enough, so the polishing pad 25 is not suitable for coarse polishing, and the life span of the polishing pad 25 is short.
FIG. 3 shows a sectional view of a second conventional polishing pad. U.S. Pat. No. 5,578,362 discloses a polishing pad 35 that is an independent foaming-type polishing pad comprising a plurality of holes 353 and a resin 352. A method for manufacturing the polishing pad 35 is filling the resin 352 (which is usually a foaming polymer formed by thermoplastic polyurethane) into a columnar mold. After cooling and solidifying, the polishing pad is produced by cutting the resin into slices. The polishing pad 35 is harder and more wearable than the first conventional polishing pad 25 (shown in FIG. 2) and has an independent bubble structure, which is often used in high planarization polishing. However, the biggest problem of the polishing pad 35 is that the concentration of the resin 352 is not easy to be uniformly distributed in the columnar mold. When forming, the differences between the temperature distributions of each position in the columnar mold cause the various sizes and uneven distribution of the holes 353, and the forming is difficult to be controlled. After slicing process, the holes 353 with different sizes of a sliced surface are more obvious. Besides, the holes 353 are not connected to each other and slurry is not easy to flow there between. When polishing, the slurry is unable to infiltrate into the interior region of the polishing pad, which reduces the slurry retention rate of the surface. In another aspect, due to the high hardness, low heat compression rate, it is easy to scrap the substrate to be polished and the polishing pad 35 is only suitable for coarse polishing.
Therefore, a novel polishing pad in the field is needed to be developed to overcome the defect of the aforementioned non-woven-fabric-type polishing pad and independent foaming-type polishing pad and to expand the scope of its use.

SUMMARY OF THE INVENTION

The present invention is to add a plurality of auxiliary fiber filaments in an independent foaming-type polishing pad, and the polishing pad obtained has high hardness of the independent foaming-type polishing pad. Additionally, the polishing pad has advantages of a non-woven-fabric-type polishing pad such as improving polishing uniformity, and partial elasticity. Furthermore, slurry can also infiltrate into the interior region by the auxiliary fiber filaments which can increase the slurry retention rate of the polishing pad.
The present invention provides a polishing pad comprising:

- a foaming resin frame comprising a plurality of holes; and
- a plurality of auxiliary fiber filaments, wherein each of the auxiliary fiber filaments is independent and dispersed randomly in the foaming resin frame.

The present invention also provides a polishing apparatus comprising:

- a polishing plate;
- a substrate;
- the aforementioned polishing pad which is adhered on the polishing plate for polishing the substrate; and
- a slurry contacting with the substrate for polishing.

The present invention further provides a method for manufacturing the aforementioned polishing pad comprising:

- (a) providing a carrier, wherein the carrier is a releasing material;
- (b) providing a foaming resin composition;
- (c) providing a plurality of auxiliary fiber filaments;
- (d) randomly dispersing the auxiliary fiber filaments of the step (c) in the foaming resin composition of the step (b);
- (e) coating the foaming resin composition randomly dispersed with the auxiliary fiber filaments of the step (d) on the carrier of the step (a); and
- (f) curing the foaming resin composition of the step (e).

- (a) providing a mold;
- (b) providing a foaming resin composition;
- (c) providing a plurality of auxiliary fiber filaments;
- (d) randomly dispersing the auxiliary fiber filaments of the step (c) in the foaming resin composition of the step (b);
- (e) filling the foaming resin composition randomly dispersed with the auxiliary fiber filaments randomly of the step (d) in a cavity of the mold (a);
- (f) curing the foaming resin composition of the step (e); and
- (g) slicing the cured foaming resin composition of the step (f) for obtaining the polishing pad.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a polishing apparatus with a conventional polishing pad.

FIG. 2 shows a sectional view of a first conventional polishing pad;

FIG. 3 shows a sectional view of a second conventional polishing pad;

FIG. 4 shows a sectional view of a polishing pad according to the present invention; and

FIG. 5 shows a schematic view of a polishing apparatus with a polishing pad according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a polishing pad (shown in FIG. 4) comprising:

- to a foaming resin frame comprising a plurality of holes; and
- a plurality of auxiliary fiber filaments, wherein each of the auxiliary fiber filaments is independent and dispersed randomly in the foaming resin frame.

The term “foaming resin frame” as used herein refers to a main part of a polishing pad which is substantially formed by a foaming resin.
The foaming resin according to the invention is, preferably, an elastomer. As used herein, the term “elastomer,” also known as “elastic polymer,” refers to a type of polymer that exhibits rubber-like qualities. When polishing, the elastomer serves as a good buffer to avoid scraping a surface of the substrate to be polished. As used herein, the term “foaming resin” refers to a material containing a thermoplastic resin and a thermodecomposing foaming agent. Preferably, the resin comprises at least one selected from the group consisting of polyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastic rubber, polystyrene, poly aromatic molecules, fluorine-containing polymer, polyimide, crosslinked polyurethane, crosslinked polyolefin, polyether, polyester, polyacrylate, elastic polyethylene, polytetrafluoroethene, poly (ethylene terephthalate), poly aromatic amide, polyarylalkene, polymethyl methacrylate, a copolymer thereof, a block copolymer thereof, a mixture thereof, and a blend thereof.
A manner of foaming the resin according the invention can be chemically foaming or physically foaming, wherein the chemically foaming manner uses an agent to carry on a chemical reaction to yield gas for being evenly distributed in the resin composition. Besides, the physically foaming manner comprises infiltrating gas into the resin composition for being evenly distributed in the resin composition by stirring.
The foaming resin frame according the invention comprises a plurality of holes which are formed by foaming. The holes are continuous holes or independent holes. The term “continuous holes” as used herein refers to at least two holes connecting to each other to form holes similar to ant nests. Generally, the continuous holes are formed by chemically foaming The term “independent holes” as used herein refers to holes which are independent without connecting to each other, and are similar to bubbles. Generally, the independent holes are formed by physically foaming. Preferably, the holes are independent holes, wherein each of a plurality of holes is independent.
One of technical features according to the invention is to provide a plurality of auxiliary fiber filaments. The term “fiber” as used herein refers to a single fiber or composite fiber; preferably, the fiber is a composite fiber. Artisans skilled in this field can choose the fiber according to the material to be polished. Artisans skilled in this field can choose suitable kinds of fibers according to the disclosure of the specification by coordination the compatibility between the foaming resin frame and fibers. The auxiliary fiber filaments according the invention have a filamentous structure; preferably, the filamentous structure is a short filamentous or short rod-like structure. Each of the auxiliary fiber filaments is independent which does not form a net structure, and the auxiliary fiber filaments are not interlaced, also not bonded, weaved, knitted, piled or stitched to form a fabric. In one preferred embodiment of the invention, the length of the auxiliary fiber filaments is from about 0.1 mm to about 1.0 mm; preferably from about 0.2 mm to about 0.8 mm; more preferably from about 0.4 mm to about 0.6 mm. In another aspect, the thickness of the auxiliary fiber filaments is from about 2 denier to about 5 denier. Preferably the auxiliary fiber filaments are made of at least one material selected from the group consisting of polyamide, terephthalamide, polyester, polymethyl methacrylate, polyethylene terephthalate, and polyacrylonitrile, and many kinds of materials of the auxiliary fiber filaments can be applied in the same polishing pad.
A suitable content of the auxiliary fiber filaments according to the invention can be chosen by the hardness, the removing rate and the slurry retention rate. Preferably, the ratio of the auxiliary fiber filaments is from about 1% to about 30% by weight; more preferably from about 5% to about 20% by weight.
In one preferred embodiment of the invention, a plurality of the auxiliary fiber filaments protrude from a surface of the foaming resin frame, wherein the auxiliary fiber filaments are semi-inlaid or semi-sunk in the foaming resin frame and semi-exposed on the surface of a polishing pad which form a structure similar to fluff. The polishing pad according to the embodiment due to the soft auxiliary fiber filaments protruding on the surface can further reduce the scratche probability of a substrate to be polished, and it can also increase the slurry retention rate on the surface of the polishing pad which can promote the polishing effect.
According to the invention, a plurality of the auxiliary fiber filaments are added in the polishing pad, preferably in the independent foaming-type polishing pad which has the advantages of the independent foaming-type polishing pad such as high hardness. Additionally, the polishing pad has advantages of the non-woven-fabric-type polishing pad such as improving polishing uniformity, and partial elasticity. Furthermore, slurry can also infiltrate into the interior region by the auxiliary fiber filaments which can increase the slurry retention rate of the polishing pad
In one preferred embodiment of the invention, the polishing pad further comprises a plurality of polishing particles which are dispersed randomly in the foaming resin frame and can locate in a resin part or in a hole part of the foaming resin frame. Preferably, the polishing particles comprise cerium dioxide, silicon dioxide, aluminum oxide, yttrium oxide, or ferric oxide. Additionally, the particle diameter of the polishing particle is from 0.01 μM to 10 μM.
The invention also provides a polishing apparatus comprising:

- a polishing plate;
- a substrate;
- the polishing pad which is adhered on the polishing plate for polishing the substrate; and
- a slurry contacting with the substrate for polishing.

Preferably the polishing apparatus further comprising:

- a lower base plate which is positioned opposite to a upper base plate; and
- a mounting sheet which is adhered to the lower base plate for carrying and mounting the substrate.

FIG. 5 shows a schematic view of a polishing apparatus according to the polishing pad of the invention. The polishing apparatus 5 includes a lower base plate 51, a mounting sheet 52, a substrate 53, an upper base plate 54, a polishing pad 55 and slurry 56. The lower base plate 51 is positioned opposite to the upper base plate 54. The mounting sheet 52 is adhered to the lower base plate 51 through an adhesive layer (not shown) and is used for carrying and mounting the substrate 53. The polishing pad 55 is mounted on the upper base plate 54, and faces to the lower base plate 51 for polishing the substrate 53.
The operation mode of the polishing apparatus 5 is as follows. First, the substrate 53 is mounted on the mounting sheet 52, and then both the upper and lower base plates 54 and 51 are rotated and the lower base plate 51 is simultaneously moved downward, such that the polishing pad 55 contacts the surface of the substrate 53, and the substrate 53 may be performed by continuously supplementing the slurry 56 and using the effect of the polishing pad 55.
The present invention also provides a first method for manufacturing the aforementioned polishing pad comprising:

The term “carrier” as used herein refers to an element which allows the foaming resin composition formed thereon and the foaming resin composition can be easily removed after curing. Preferably, the carrier is a sheet; in another aspect, the carrier is a releasing material. The term “releasing material” as used herein refers to a material which does not react with the foaming resin composition in the polishing pad manufacturing process and the foaming resin composition can be easily removed after the curing. Preferably, the releasing material is “a film with low permeability.” The term “film with low permeability” as used herein refers to a film or thin film that substantially prevents the foaming resin composition on an upper surface of the film with low permeability according to the invention from permeating to a lower surface of the film with low permeability. In one preferred embodiment of the invention, the film with low permeability can be formed on a base material, for example, a paper. Preferably, the carrier comprises a polyethylene glycol terephthalate film, a polypropylene film, a polycarbonate film, a polyethylene film, a polyethylene terephthalate film, a releasing paper or a releasing fabric. Additionally, the preferable polypropylene is oriented polypropylene.
Preferably, the carrier is continuously provided, for example, is a rolling releasing material. The rolling releasing material can be used by roll to roll. Comparing to the conventional manufacture relative to molding or casting a single polishing pad, the method according to the invention improves batch uniformity.
In one embodiment of the invention, the foaming resin composition comprises a resin, a foaming agent, and a bridging agent.
The term “bridging agent” as used herein refers to an agent that may generate a crosslinked reaction with the resin according to the invention and cure the resin under an appropriate condition. The kind of the bridging agent is determined according to the kind of the resin.
The step (d) according to the invention is randomly dispersing the auxiliary fiber filaments of the step (c) in the foaming resin composition of the step (b). The manner may be chosen by artisans skilled in this field, for example, mixing or stirring together with components of the foaming resin composition to obtain the foaming resin composition and randomly dispersing the auxiliary fiber filaments in the foaming resin composition at the same time. In one preferred embodiment of the invention, the steps (b), (c), and (d) can be performed at the same time.
In one embodiment of the invention, the step (d) comprises blade coating, printing wheel coating, roll extrusion coating or spraying. The manner of coating may be chosen by artisans skilled in this field. Besides, the preferred coating is continuously coating.
The method according the invention, the step (f) is curing the foaming resin composition of the step (e). The manner of curing may be chosen by artisans skilled in this field according to the kind of the curing resin and the optional bridging agent. In one preferred embodiment of the invention, the curing step is curing the foaming resin composition which has been dried at a high temperature of 60° C. to 130° C.
In one preferred embodiment of the invention, the method further comprises a step (g) of removing the carrier. Preferably, the step of removing the carrier is removing the polishing pad from manufacturing equipment after the manufacture method is completed. On the other hand, the step of removing the carrier is removing the carrier from the polishing pad when polishing. The specific manner of the removing depends on the carrier, for example, the manner is peeling.
The present invention also provides a second method for manufacturing the aforementioned polishing pad comprising:

In the second method for manufacturing the polishing pad, the steps (b), (c), (d), and (f) are practiced in the same manners of the aforementioned first method for manufacturing the polishing pad.
Preferably, in the second method for manufacturing the polishing pad according to the invention, the mold of the step (a) is a cylindrical mold. The manner may be chosen by artisans skilled in this field. The step (e) is to fill the foaming resin composition with the randomly dispersed auxiliary fiber filaments of the step (d) in the cavity of the mold of the step (a). The manner may be chosen by artisans skilled in this field.
The step (g) according to the invention is to slice the cured foaming resin composition of the step (f) for obtaining the polishing pad. The manner may be chosen by artisans skilled in this field, for example, using a knife to shave a cured resin into slices for manufacturing the polishing pad.
In one preferred embodiment of the invention, the first or second method for manufacturing the polishing pad further comprises a surface finishing step, which is finishing a surface of the cured resin composition. The embodiment of finishing is polishing or shaving a part of the surface. The manner of polishing or shaving the part of the surface may be chosen by artisans skilled in this field, for example, using sandpaper to polish or a knife to shave; wherein the manners of the polishing or shaving are well known to artisans skilled in this field.
The following Examples are given for the purpose of illustration only and are not intended to limit the scope of the present invention.

EXAMPLE

A resin composition is stirred uniformly and air is infiltrated into the resin composition at a rate of 1000 rpm to 4000 rpm. Then, the resin composition is coated on a releasing paper with a scraper. The resin composition is cured at 110° C. for 1 minute, and then dried at 80° C. for 30 seconds in an oven, and the surface is shaved.
While embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by persons skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention is not limited to the particular forms as illustrated, and that all the modifications not departing from the spirit and scope of the present invention are within the scope as defined in the appended claims.

Claims

What is claimed is:

1. A polishing pad comprising:

a foaming resin frame comprising a plurality of holes; and

a plurality of auxiliary fiber filaments, wherein each of the auxiliary fiber filaments is independent and dispersed randomly in the foaming resin frame.

2. The polishing pad according to claim 1, wherein the foaming resin frame comprises at least one selected from the group consisting of polyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastic rubber, polystyrene, polyaromatic molecules, fluorine-containing polymer, polyidmide, cross-linked polyurethane, cross-linked polyolefin, polyether, polyester, polyacrylate, elastic polyethylene, polytetrafluoroethylene, poly(ethylene terephthalate), polyaromatic amide, polyarylalkene, polymethyl methacrylate, a copolymer thereof, a block copolymer thereof, a mixture thereof, and a blend thereof.

3. The polishing pad according to claim 1, wherein each of a plurality of holes is independent.

4. The polishing pad according to claim 1, wherein the length of the auxiliary fiber filaments is from about 0.1 mm to about 1.0 mm.

5. The polishing pad according to claim 1, wherein the thickness of the auxiliary fiber filaments is from about 2 denier to about 5 denier.

6. The polishing pad according to claim 1, wherein the ratio of the auxiliary fiber filaments is from about 1% to about 30% by weight.

7. The polishing pad according to claim 1, wherein the auxiliary fiber filaments are made from at least one selected from the group consisting of polyamide, p-phenylenediamine, polyester, polymethyl methacrylate, polyethylene terephthalate and polyacrylonitrile.

8. The polishing pad according to claim 1, wherein a plurality of the auxiliary fiber filaments protrude from a surface of the foaming resin frame.

9. The polishing pad according to claim 1, wherein further comprises a plurality of polishing particles which are dispersed randomly in the foaming resin frame.

10. A polishing apparatus comprising:

a polishing plate;

a substrate;

the polishing pad according to claim 1, which is adhered on the polishing plate for polishing the substrate; and

a slurry contacting with the substrate for polishing.

11. The polishing apparatus according to claim 10, wherein the foaming resin frame comprises at least one selected from the group consisting of polyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastic rubber, polystyrene, polyaromatic molecules, fluorine-containing polymer, polyidmide, cross-linked polyurethane, cross-linked polyolefin, polyether, polyester, polyacrylate, elastic polyethylene, polytetrafluoroethylene, poly(ethylene terephthalate), polyaromatic amide, polyarylalkene, polymethyl methacrylate, a copolymer thereof, a block copolymer thereof, a mixture thereof, and a blend thereof.

12. The polishing apparatus according to claim 10, wherein each of a plurality of holes is independent.

13. The polishing apparatus according to claim 10, wherein the length of the auxiliary fiber filaments is from about 0.1 mm to about 1.0 mm.

14. The polishing apparatus according to claim 10, wherein the thickness of the auxiliary fiber filaments is from about 2 denier to about 5 denier.

15. The polishing apparatus according to claim 10, wherein the ratio of the auxiliary fiber filaments is from about 1% to about 30% by weight.

16. The polishing apparatus according to claim 10, wherein the auxiliary fiber filaments are made from at least one selected from the group consisting of polyamide, p-phenylenediamine, polyester, polymethyl methacrylate, polyethylene terephthalate and polyacrylonitrile.

17. The polishing apparatus according to claim 10, wherein a plurality of the auxiliary fiber filaments protrude from a surface of the foaming resin frame.

18. The polishing apparatus according to claim 10, wherein further comprises a plurality of polishing particles which are dispersed randomly in the foaming resin frame.

19. A method for manufacturing the polishing pad according to claim 1 comprising:

(a) providing a carrier, wherein the carrier is a releasing material;

(b) providing a foaming resin composition;

(c) providing a plurality of auxiliary fiber filaments;

(d) randomly dispersing the auxiliary fiber filaments of the step (c) in the foaming resin composition of the step (b);

(e) coating the foaming resin composition randomly dispersed with the auxiliary fiber filaments of the step (d) on the carrier of the step (a); and

(f) curing the foaming resin composition of the step (e).

20. The method according to claim 19, wherein the carrier comprises a polyethylene glycol terephthalate film, a polypropylene film, a polycarbonate film, a polyethylene film, a polyethylene terephthalate film, a release releasing paper or a release releasing fabric.

21. The method according to claim 19, wherein the carrier is continuously provided.

22. A method for manufacturing the polishing pad according to claim 1 comprising:

(a) providing a mold;

(b) providing a foaming resin composition;

(c) providing a plurality of auxiliary fiber filaments;

(e) filling the foaming resin composition randomly dispersed with the auxiliary fiber filaments randomly of the step (d) in a cavity of the mold (a);

(f) curing the foaming resin composition of the step (e); and

(g) slicing the cured foaming resin composition of the step (f) for obtaining the polishing pad.