KR101009626B1 - Method of manufacturing a polishing pad - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polishing pad for use in a CMP process such as a silicon wafer, a plate glass for display, etc. The fabric is characterized in that the fabric is eluted from the curable resin layer 4 to form voids 2.

The present invention can manufacture a polishing pad in which pores are formed in a continuous process, and at the same time easily control the size and distribution density of the pores (2) formed by appropriately adjusting the structure of the fabric, the fineness of the usable yarn, and the like. The uniformity of the voids can also be improved.

Therefore, the polishing pad manufactured according to the present invention has the advantage of low scratch rate during polishing and excellent polishing performance.

Polishing, Pad, CMP, Wafer, Pore, Elution, Soluble Yarn, Fabric, Curable Resin

Description

Method of manufacturing a polishing pad

1 is a schematic cross-sectional view of a polishing pad according to the present invention.

2 is a schematic cross-sectional view showing a state in which the curable resin layer 1 is formed on the fabric 4.

FIG. 3 is a schematic cross-sectional view showing a state in which a fabric is eluted from the curable resin layer 1 of FIG. 2 and voids are formed.

Figure 4 is a schematic cross-sectional view of a conventional polishing pad.

* Code description for main parts of the drawings

DESCRIPTION OF SYMBOLS 1 Curable resin layer 2 voids 3 adhesive layer

4: fabric

The present invention is useful for chemical mechanical polishing (CMP), particularly for CMP methods of planarizing flat glass or other substrates for silicon wafers or displays used in the manufacture of integrated circuit chips or the like. It relates to a method for producing a polishing pad.

The silicon wafer and the like are smoothly processed by the CMP polishing apparatus, and the CMP polishing apparatus includes a lower board having a circular rotating plate on which the polishing pad is mounted, an upper board which adheres the silicon wafer to the polishing pad, and a device for supplying slurry to the polishing pad. do.

Chemical-mechanical polishing, a CMP operation, pushes the surface of the semiconductor wafer on which the integrated circuit will be fabricated in the opposite direction to remove oxides, including deposited Si-based oxides, and creates a very smooth and flat surface on the wafer. As an operation, deionized water and / or chemically active reagents are applied along with the polishing liquid to the interface between the wafer and the polishing pad during the CMP operation.

In the prior art of manufacturing a polishing pad, Korean Patent Laid-Open Publication No. 2000-70068 discloses forming a photoreactive resin layer on a substrate by coating or laminating, and then placing an optical mask having a predetermined pattern on the photoreactive resin layer. Next, a method of manufacturing a polishing pad by irradiating an electromagnetic beam to the photoreactive resin layer on the photomask is disclosed.

Specifically, a portion of the photoreactive resin layer in which electromagnetic radiation is blocked by a photomask does not cause photoreaction, and thus is removed in a later process to form voids 2, and a portion in which photomagnetic rays are not blocked by a photomask is A method of manufacturing a polishing pad in which voids (2) are formed on a surface thereof as shown in FIG. Is showing.

Figure 4 is a schematic cross-sectional view of the polishing pad produced by the conventional method.

However, since the conventional method employs a photo transfer method using an optical mask, there is a limit in miniaturizing the size of the voids 2 or changing the shape at will, and it is difficult to uniformize the sizes of the voids 2. there was.

In addition, the conventional method described above has a problem in that the production efficiency is lowered because the polishing pad cannot be manufactured in a continuous process.

In order to solve the above-mentioned problems, the present invention forms a curable resin layer 4 on a fabric 4 made of a soluble yarn, and then buffs and elutes the fabric to the curable resin layer 4. It is intended to provide a method for manufacturing a polishing pad by eluting from the voids (2).

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, the manufacturing method of the polishing pad according to the present invention is applied to the curable resin on the fabric (4) consisting of a soluble yarn and cured to form a curable resin layer (1), and then the fabric (4) is recessed One surface of the curable resin layer 1 is buffed to expose a portion of the fabric 4 out of the curable resin layer 1, and then treated with hot water or an aqueous alkali solution to elute the fabric 4 to form a curable resin layer ( It is characterized by forming the voids (2) on one surface of 1).

Specifically, in the present invention, as shown in FIG. 2, the curable resin is first applied onto a fabric 4 composed of a water-soluble yarn dissolved in hot water or an aqueous alkali solution and then cured to form a curable resin layer 1. Form.

2 is a schematic cross-sectional view showing a state in which the curable resin layer 1 is formed on the fabric 4.

The water-soluble yarn is a yarn dissolved in hot water or an aqueous alkali solution, specifically, a polyvinyl alcohol yarn dissolved in hot water or an alkali-soluble copolyester yarn dissolved in an aqueous alkali solution.

The alkali-soluble copolyester yarn is polyethylene terephthalate as a main component, polyethylene glycol, polypropylene glycol, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedicar At least one selected from carboxylate, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, 2,2,4-trimethyl1,3-propanediol and adipic acid Copolyester copolymerized with an additional component.

The usable yarn is a multifilament composed of monofilaments having a fineness of 0.5 to 10 denier, or a monofilament having a fineness of 0.5 to 10 denier.

That is, the usable yarn is a multifilament or a monofilament, and its single yarn fineness or total fineness is preferably about 0.5 to 10 denier.

When the single yarn fineness or the total fineness exceeds 10 denier, the voids 2 are formed too large to reduce the polishing performance. When the single fineness or the total fineness is less than 0.5 denier, the polishing performance is improved, but the manufacturing process is complicated.

The fabric 4 is preferably woven into a tissue selected from plain weave and twill weave.

However, in the present invention, the structure of the fabric 4 is not particularly limited.

As the curable resin, a thermosetting polyurethane resin or a photocurable polyurethane resin is used.

Next, one side of the curable resin layer 1 in which the fabric 4 is recessed is buffed to expose a part of the fabric 4 outside the curable resin layer 1 and then treated with hot water or an aqueous alkali solution. To elute the fabric 4 to form voids 2 on one surface of the curable resin layer 1 to produce a polishing pad.

When the water-soluble fiber is polyvinyl alcohol, it is eluted with hot water, and when it is a copolyester, it is eluted with an aqueous alkali solution.

It is more preferable that the adhesive layer 3 is formed on one surface of the polishing pad which is manufactured by the above-described method and on which one side of the polishing pad is formed.

In the present invention, instead of forming voids 2 on the surface of the polishing pad by a photo transfer method or a molding method, the curable resin layer 4 is formed on the fabric 4 made of a usable yarn, and then buffed and eluted. Since the fabric is eluted from the curable resin layer 4 through the process to form the voids 2, the polishing pad can be manufactured in a continuous process.

In addition, the present invention can easily control the size and distribution density of the pores 2 by adjusting the texture of the fabric or the fineness of the yarn constituting the fabric, it is also possible to increase the uniformity of the pores. Therefore, the polishing pad manufactured by the present invention is excellent in polishing performance and the like.

In the present invention, the surface roughness and scratch occurrence rate of the polished silicon wafer were evaluated as follows.

Surface Average Roughness of Silicon Wafers

Carl Zeiss, a type of confocal laser scanning microscope (LSM) facility, LSM 5 PASCAL, a topography software package for LSM, or similar performance. Measure by using LSM equipment.

Specifically, the center line average roughness (Ra) value of 10 irregularities formed on the surface based on JIS B 0601 by scanning the surface area range (width 1,000 μm × length 1,000 μm) of the polished silicon wafer with a laser Is measured and the ten point average roughness Rz of the surface of the polished silicon wafer is obtained from the arithmetic mean value.

Hereinafter, the ten point average roughness Rz is called surface average roughness.

Scratch Rate (%)

The number of scratches generated when scratching a silicon wafer with 100 square inch area by polishing pad is identified and substituted into the following equation.

Scratch Rate (%) = (Scratch Count / 100 Sq Inch) x 100

However, if the number of scratches exceeds 100, leave it at 100.

The scratch reading is judged by visual judgment by a skilled expert, and in the case of a faint defect that is difficult to read whether it is scratched with the naked eye, it may rely on the additional measurement of an optical microscope equipped with dark field illumination and image analysis software.

In addition, the scratch judges the scratch that the ratio of the length in the longitudinal direction and the width direction to be 10 to 1 or more.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

However, the present invention is not particularly limited by the following examples.

Example 1

Using a polyvinyl alcohol multifilament having a single denier fineness of 1 denier as a warp yarn and a weft yarn, a plain weave fabric (4) was fabricated. The resin was cured by irradiation of ultraviolet rays to form a curable resin layer 1 in which the fabric 4 was recessed as shown in FIG. 2.

Next, one side of the curable resin layer 1 in which the fabric is recessed is buffed with 150 mesh sander paper to expose a portion of the fabric 4 outside the curable resin layer 1, and then 100 ° C. hot water The fabric 4 was eluted to prepare a curable resin layer 1 having voids 2 formed thereon as shown in FIG. 3.

Next, an adhesive layer 2 was formed on one surface of the curable resin layer 1 in which voids 2 were not formed, thereby preparing a polishing pad as shown in FIG. 1.

100 square inches of the silicon wafer was polished under the following conditions using the prepared polishing pad.

Polishing condition

-Polishing machine: GNP Technology's Poli-500 Polisher

-Polishing time: 10 minutes

Down force: 250g / cm2 (3.5psi) on the wafer surface

-Polishing Table Speed: 120rpm

Wafer Carrier Speed: 120rpm

Slurry flow rate: 700 ml / min

-Slurry type: Nalco 2731, silica slurry diluted with DIW and slurry at 15: 1

Table 1 shows the results of measuring surface average roughness and scratch rate of the polished (polished) silicon wafer.

Example 2

A water-soluble copolyester having a single yarn fineness of 1 denier (1,4-cyclohexanedimethanol is copolymerized with 15% by weight of polyethylene terephthalate) using a monofilament as warp and weft yarn to prepare a twill fabric (4). The thermally reactive polyetherurethane resin was coated on the fabric 4 to a thickness of 20 mm and then heat-treated to form the curable resin layer 1 in which the fabric 4 was recessed as shown in FIG. 2.

Next, one side of the curable resin layer 1 in which the fabric is recessed is buffed with 150 mesh sandpaper to expose a portion of the fabric 4 outside the curable resin layer 1 and then treated with NaOH aqueous solution. The fabric 4 was eluted to form a curable resin layer 1 having voids 2 formed thereon as shown in FIG. 3.

Next, an adhesive layer 2 was formed on one surface of the curable resin layer 1 in which voids 2 were not formed, thereby preparing a polishing pad as shown in FIG. 1.

100 square inches of the silicon wafer was polished under the same polishing conditions as in Example 1 using the prepared polishing pad.

Table 1 shows the results of measuring the surface average roughness and scratch rate of the polished (polished) silicon wafer as described above.

Comparative Example  One

The photoreactive polyesterurethane resin used in Example 1 was coated on the polyester film to a thickness of 200 mm to form a photoreactive resin layer, and then alternately blocking ultraviolet rays at 100 μm intervals on the photoreactive resin layer. The photomask to pass through was arranged, and the ultraviolet-ray was irradiated to this, and the polishing pad which has a cross-sectional structure as shown in FIG. 4 was manufactured.

100 square inches of the silicon wafer was polished under the same polishing conditions as in Example 1 using the prepared polishing pad.

Table 1 shows the results of measuring the surface average roughness and scratch rate of the polished (polished) silicon wafer as described above.

Measurement results of polished wafer properties division Example 1 Example 2 Comparative Example 1 Surface Average Roughness of Polished Wafers 13.87 13.89 14.51 Scratch Rate (%) 0.11 0.12 0.17

In Examples 1 and 2, the voids were uniformly formed on the surface, and scratch rate and polishing performance (surface average roughness of the polished wafer) were better than those of Comparative Example 1.

In addition, in Example 1 and Example 2, although the polishing pad could be manufactured by a continuous process, in Comparative Example 1, the polishing pad could not be manufactured by the continuous process.

The present invention can manufacture a polishing pad in which pores are formed in a continuous process, and at the same time easily control the size and distribution density of the pores (2) formed by appropriately adjusting the structure of the fabric, the fineness of the usable yarn, and the like. The uniformity of the voids can also be improved.

Therefore, the polishing pad manufactured according to the present invention has the advantage of low scratch rate during polishing and excellent polishing performance.

Claims (9)

After forming the curable resin layer (1) on the fabric (4) made of a soluble yarn, one side of the curable resin layer (1) in which the fabric (4) is recessed to buff a portion of the fabric (4) Exposing the resin layer 1 and then treating it with hot water or an aqueous alkali solution to elute the fabric 4 to form voids 2 on one surface of the curable resin layer 1. Way. The method for producing a polishing pad according to claim 1, wherein the water-soluble yarn is one selected from polyvinyl alcohol yarns and alkali-soluble copolyester yarns. The method of claim 2, wherein the alkali-soluble copolyester yarn is polyethylene terephthalate as a main component, polyethylene glycol, polypropylene glycol, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanedimethanol, 1,4 -Cyclohexanedicarboxylate, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, 2,2,4-trimethyl1,3-propanediol and adipic acid Method for producing a polishing pad, characterized in that the copolymerized copolymer copolymerized with at least one selected from the additives.  The method of claim 1, wherein the curable resin is one selected from a thermosetting polyurethane resin and a photocurable polyurethane resin. The method of claim 1, wherein the soluble yarn is a method for producing a polishing pad, characterized in that the multifilament consisting of monofilaments having a fineness of 0.5 to 10 denier. The method for manufacturing a polishing pad according to claim 1, wherein the water-soluble yarn is a monofilament having a fineness of 0.5 to 10 denier. The method of manufacturing a polishing pad according to claim 1, wherein the tissue of the fabric (4) is one selected from plain weave and twill weave. The method of manufacturing a polishing pad according to claim 1, wherein an adhesive layer (3) is formed on one surface of the both surfaces of the polishing pad, which is different from the one on which the voids (2) are formed. The method for manufacturing a polishing pad according to claim 1, wherein the water-soluble yarn is dissolved by one selected from hot water and an aqueous alkali solution.

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