KR20090020534A - Polishing pad and method of manufacturing the same - Google Patents

Abstract

A polishing pad and a method of manufacture thereof are provided to guarantee the excellent adhesion strength of the polishing pad and the surface plate and to prevent the scratch in polishing by the polishing pad is instead of adhered to adhesive to the surface plate with a bolt. A polishing pad(P) comprises the abrasive layer(1); the fastener mechanism support layer(2) formed in the rear side of abrasive layer, and the groove(4) for the fastener mechanism passing through to the rear side in the surface of the polishing pad. The polishing pad is connected by the fastener mechanism in the surface plate, and the fastener mechanism support layer is the first class selected between the hard resin layer and the metal sheet.

Description

Polishing pad and method of manufacturing the same

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. A polishing pad and a method of manufacturing the same.

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.

As a polishing pad used in a conventional CMP method, Japanese Laid-Open Patent Publication No. 2005-330621 discloses a surface of a pad (A) impregnated with a polyurethane resin, which is a polymer elastomer in a nonwoven fabric composed of short fibers, as shown in FIG. 6. A method of manufacturing a polishing pad having a flat surface by heat treatment at a temperature higher than the softening temperature thereof is disclosed.

It is fixed to the surface plate using polishing pad fixing material and used for CMP operation.

Japanese Laid-Open Patent Publication No. 2003-238916 discloses a polishing pad fixing holding material having a cross-sectional structure as shown in FIG.

In the polishing pad fixing holding material, a thermally sensitive adhesive layer B ₂ is formed on one side of the support film B ₁ to be bonded to the polishing pad A, and the other side is a pressure sensitive adhesive to the surface plate. The adhesive layer B ₃ is formed.

When the polishing pad A of FIG. 6 disclosed in Japanese Laid-Open Patent Publication No. 2005-330621 is attached to a surface plate using the polishing pad fixing holding material shown in FIG. 7, the polishing pad A of FIG. According to the skill of the operator, bubbles are more likely to penetrate the back surface, and the adhesion state of the polishing pad is more likely to be uneven. The polishing slurry is highly likely to penetrate into the adhesive layer of the non-uniformly attached polishing pad, and the penetrating polishing slurry may cause peeling of the support film B1, which is an adhesive layer, and additionally, a polishing phenomenon of the polishing pad during polishing. As a result, the life of the polishing pad may be shortened, and the quality of the polishing pad may be deteriorated. In addition, since the difference between good and bad adhesion state with the surface plate according to the proficiency of the person attaching the polishing pad occurs a problem that can maintain a high quality polishing pad attachment state only by skilled workers.

In addition, since the conventional method is used by adhering one polishing pad to one surface plate, as the diameter of the wafer increases, the surface plate and the polishing pad should gradually increase in size.

As a result, there has been a problem that a process for producing a large polishing pad becomes more difficult.

In order to solve the problem that the manufacturing process becomes complicated due to the enlargement of the polishing pad as described above, Korean Patent No. 0485846 manufactures a polishing pad tile such as a shape in which the polishing pad is separated into pieces, and then, these are shown in FIG. 4. A mosaic polishing pad is proposed by using a polishing pad-holding holding material such as shown in Fig. 1, in other words, assembled and attached to a surface plate using an adhesive in a mosaic manner.

However, the prior art can solve the trouble of having to manufacture a large size of the polishing pad, but since the polishing pad tiles are attached to the surface with adhesive, the adhesive strength between them is weak and according to the skill of the person attaching the polishing pad. Since there is a lot of difference between good and bad state of adhesion with the surface plate, the problem that can maintain the high quality polishing pad attachment state by skilled technicians has not been solved.

In order to solve the above problems, the present invention can be attached to the surface plate with a fastening mechanism such as a bolt instead of an adhesive, thereby decreasing the polishing performance and increasing defects caused by poor adhesion between the polishing pad and the surface plate during the polishing process. To provide a polishing pad that effectively prevents such problems.

The present invention provides a fastening mechanism groove penetrating through the surface of the polishing layer (1), the fastener support layer (2) formed on the back surface of the polishing layer (1) and the polishing pad so as to achieve the above object ( 4) is provided with a polishing pad characterized in that is fastened to the surface plate (J) by a fastening mechanism (F).

The present invention has excellent adhesive strength with the surface plate because it is attached to the surface plate with fasteners such as bolts instead of adhesives, and the polishing performance decreases due to poor adhesion between the polishing pad and the surface plate during the polishing process or scratches during polishing. Can effectively solve problems.

In addition, the polishing pad of the present invention has a very high flatness of the polishing pad itself by hard bonding of a hard layer having a good flatness formed on the back surface and the polishing pad, and is combined with a fastening mechanism, so that even a skilled technician does not have to follow a work standard. When the polishing pad is attached and detached on the surface plate, the result of the processing of the polishing product is excellent, so that a uniform polishing result can be obtained.

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

First, the polishing pad according to the present invention includes a polishing layer 1, a fastener support layer 2 formed on the back surface of the polishing layer 1, and the surface of the polishing pad as shown in FIGS. Consists of the fastening mechanism grooves (4) to be fastened to the surface plate (J) by the fastening mechanism (F).

1 is a plan view of a polishing pad according to the present invention, Figures 2 to 3 is a state in which the groove 4 for the fastening mechanism of the polishing pad shown in Figure 1 is cut perpendicularly to the longitudinal direction of the polishing pad It is sectional drawing which shows.

The polishing layer 1 is a pad selected from a pad in which a polymer elastomer is impregnated in a nonwoven fabric, a pad composed of only a polymer elastomer, and a pad in which a polymer elastomer layer is laminated on a pad in which a polymer elastomer is impregnated in a nonwoven fabric.

In the present invention, the structure and type of the polishing layer 1 are not particularly limited.

The fastener support layer 2 is a hard resin layer or a metallic plate.

It is preferable that the hard resin layer which comprises the fastener mechanism support layer 2 is 40-100 hardness measured by the durometer hardness meter D-type (Type).

The durometer durometer D-type is a GS-702 G model durometer from Teclock company, the hardness is measured by the ASTM D 2240 A method.

The hard resin layer constituting the fastener support layer 2 is a polyurethane resin, a polypropylene resin, a polyester resin, a polyamide resin, a melamine resin, an epoxy resin, or the like.

The metallic plate forming the fastener support layer is preferably made of a corrosion resistant material such as stainless steel and titanium.

If the hardness of the hard resin layer constituting the fastening mechanism support layer 2 is lower than 40, a problem arises in that the fastening mechanism F such as a seal cannot be reliably supported.

In the present invention, since the fastening mechanism support layer 3 is composed of a hard resin layer or a metal plate having a high hardness as described above, the attachment and detachment of the polishing pad is easy and the degree of polishing of the abrasive is uniform regardless of the type of the polishing equipment. The effect to be reproduced is expressed.

The thickness of the fastener support layer 2 is preferably 2 to 10 mm.

When the thickness is less than 2 mm, when the polishing pad is attached to the surface plate by using the fastening mechanism F, fine deformation may occur in the polishing pad. When the thickness exceeds 10 mm, the weight may be too heavy to be difficult to handle. Can be.

Meanwhile, as illustrated in FIG. 3, an additional auxiliary hard resin layer 3 may be further inserted and formed between the polishing layer 1 and the fastener support layer 2.

The fastening mechanism F is a bolt or the like.

The auxiliary hard resin layer 3 is preferably a polyurethane resin, polypropylene resin, polytetrafluoroethylene resin, polyester resin, polyamide resin, melamine resin, epoxy resin, or the like.

The auxiliary hard resin layer 3 preferably has a hardness of 40 to 100 measured by a durometer D-type (Type).

The durometer durometer D-type is a GS-702 G model durometer from Teclock company, the hardness is measured by the ASTM D 2240 A method.

The polishing pad according to the present invention forms the fastener support layer 2 on the back surface of the polishing layer 1, and then drills the polishing layer and the fastener support layer 2 in order to form the groove 4 for the fastener. Prepared by the method.

At this time, the auxiliary hard resin layer 3 may be further formed between the polishing layer 1 and the fastener support layer 2.

In addition, before drilling the fastener support layer 2 formed on the rear surface of the polishing layer 1, it is more preferable to buff or cut the flattening process.

In order to completely bond the abrasive layer 1 and the fastener support layer 2 and to prevent peeling, it is preferable to bond using a heat-sensitive adhesive layer and / or a thermosetting resin.

When the thermal adhesive layer is used in the process of bonding the polishing layer 1 and the fastener support layer 2, the fastener support layer 2 may be prepared in advance and combined with the thermal adhesive layer. In this case, the fastener support layer 2 may be manufactured to a thickness of 2 to 10 mm, and at this time, the thickness of the fastening device support layer 2 may be about 1 to 5 mm to buff or cut both surfaces to planarize in advance.

The polishing layer 1 and the fastener support layer 2 may be combined using a two-component curable resin. In this case, the fastener support layer 2 may also be manufactured to a thickness of 2 to 10 mm. It is preferable to make the thickness about 5 mm thick and buff or cut both surfaces to planarize it in advance.

When the abrasive layer 1 and the fastener support layer 2 are joined together, a thermosetting or ultraviolet curing resin is applied to the abrasive layer 1 to form an auxiliary hard resin layer 3 on the back side of the abrasive layer 1, and then fastened. The instrument support layer 2 can also be made, wherein a method of bonding the abrasive layer and the fastener support layer can be a heat-sensitive adhesive layer, a pressure-sensitive adhesive layer, a two-component curable resin, or the like.

Further, it is more preferable to drill the fastener support layer 2 formed on the back surface of the abrasive layer 1 after the abrasive layer and the fastener support layer 2 are completely combined.

The polishing pad P of the present invention is attached to the surface plate J using fastening mechanisms F such as bolts as shown in FIGS. 4 to 5.

4 to 5 are cross-sectional views showing a state in which the polishing pad shown in FIG. 1 is attached to a surface plate.

The present invention has excellent adhesive strength with the surface plate because it is attached to the surface plate with fasteners such as bolts instead of adhesives, and the polishing performance decreases due to poor adhesion between the polishing pad and the surface plate during the polishing process or scratches during polishing. The problem can be effectively solved, there is an advantage that can maintain the fastening state of the high quality polishing pad even if the operator's skill is not very high.

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

The average roughness of the surface is obtained by using an atomic force microscope. Using the JSPM-5200 model of JEOL Ltd, the surface roughness is obtained by observing the surface curvature in three dimensions by atomic resolution using the attractive force and repulsive force between the cantilever and the sample surface atom in AFM mode. .

Specifically, three to five samples were taken from one to five centimeters each from the center of the polished silicon wafer to the left and right and up and down. It is called average roughness.

scratch Incidence (%)

Calculate the total number of scratches that cause scratch defects when polishing two 8-inch silicon wafers with a polishing pad, and substitute this into the following equation.

Scratch Rate (%) = (Number of Scratch Cases / 8 Inch, 2 Sheets) × 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  One

A polyamide filament having a single denier fineness of 1 denier was also cut to a length of 50 mm, short fibers were made through a carding and cross wrapper process, and then a web was needle-punched to prepare a nonwoven fabric.

Next, the prepared nonwoven fabric was impregnated with 40% by weight of polyurethane resin relative to the weight of the nonwoven fabric, and then wet coagulated to prepare an abrasive layer 1.

Next, the polyethylene resin is manufactured to a thickness of 5 mm using a conventional plastic sheet manufacturing method while adjusting the hardness to 60 with a durometer hardness tester D-type. One fastener support layer 2 was formed.

Next, the two-component curable resin was uniformly applied to the prepared polishing layer 1, and then the fastener support layer was bonded thereto.

Next, after buffing the back surface of the fastener support layer 2, the polishing layer and the fastener support layer 2 were sequentially drilled to form grooves 4 for the fastener, thereby manufacturing a polishing pad.

The above-described polishing pad was attached to the surface plate with bolts to the hole-processed surface plate to enable bolting, and two 8-inch silicon wafers were polished under the following conditions.

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

Example 1 except that an additional auxiliary hard resin layer 3 made of a thermosetting polyetherurethane resin was further formed between the polishing layer 1 prepared in Example 1 and the fastener support layer 2. A polishing pad was manufactured by the same process and method as described above, and two polishing pads of 8-inch silicon wafer were polished by the same polishing process as Example 1 by attaching the same to the surface plate with bolts.

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

Comparative Example  One

Instead of the island-in-the-sea composite fiber used in Example 1, polyamide short fibers having single densities of 3 deniers were manufactured through a carding and cross-wrapping process to produce laminated webs thereof, and then needle punched to prepare nonwoven fabrics.

Next, the pad (A) impregnated with a polyurethane resin in the nonwoven fabric was first prepared by impregnating 40 wt% of the nonwoven fabric with a polyurethane resin, followed by wet coagulation.

Next, the pad A was passed through a thermal roller at 300 ° C. to prepare a polishing pad having a cross section as shown in FIG. 6.

As shown in Figure 7 attached to the surface of the support film (B ₁ ) by attaching a polishing pad prepared using a polishing pad fixing holding material formed with a thermal adhesive layer (B ₂ ) and a pressure-sensitive adhesive layer (B ₃ ) respectively on the surface plate Example Two 8-inch silicon wafers were polished under the same polishing conditions as 1.

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 13.78 13.76 14.25 Scratch Rate (%) 0.10 0.11 0.17

Example 1 and Example 2 were excellent in the adhesive strength between the polishing pad and the surface plate, scratch rate and polishing performance (surface average roughness of the polished wafer) was better than Comparative Example 1.

1 is a plan view of a polishing pad according to the present invention.

2 to 3 are cross-sectional views showing a state in which the perforated groove 4 for the fastening mechanism of the polishing pad according to the present invention is cut perpendicularly to the longitudinal direction.

4 to 5 are cross-sectional views showing a state in which the polishing pad is attached to the surface plate in the present invention.

Figure 6 is a schematic cross-sectional view of a conventional polishing pad.

7 is a cross-sectional view of a conventional polishing pad fixing holding material.

* Code description for main parts of the drawings

P: Polishing pad J: Table F: Fastening mechanism

1 polishing layer 2 fastener support layer

3: auxiliary hard resin layer 4: groove for fastening mechanism

A: Pad impregnated with a polymer elastomer in a nonwoven fabric composed of ultrafine fibers

B: Holding material for fixing polishing pad

B ₁ : support film of the holding material for fixing the polishing pad

B ₂ : thermal adhesive layer of the holding material for fixing the polishing pad

B ₃ : pressure-sensitive adhesive layer of the holding material for fixing the polishing pad

Claims (18)

The fastening mechanism (F) is composed of a polishing layer (1), a fastener support layer (2) formed on the rear surface of the polishing layer (1) and fastener grooves (4) penetrating from the surface of the polishing pad to the back surface. The polishing pad, characterized in that fastened to the surface plate (J). The polishing layer (1) according to claim 1, wherein the polishing layer (1) is one pad selected from a pad in which a polymer elastomer is impregnated in a nonwoven fabric, a pad composed of only a polymer elastomer, and a pad in which a polymer elastomer layer is laminated on a pad in which a polymer elastomer is impregnated in a nonwoven fabric. Polishing pads, characterized in that. The polishing pad according to claim 1, wherein the fastener support layer (2) is one selected from a hard resin layer and a metallic plate. The polishing pad according to claim 3, wherein the hard resin layer has a hardness of 40 to 100 measured by a durometer hardness meter D-type (Type). The polishing method according to claim 3, wherein the hard resin layer is composed of one resin selected from polyurethane resin, polypropylene resin, polytetrafluoroethylene resin, polyester resin, polyamide resin, melamine resin and epoxy resin. pad. The polishing pad according to claim 1, wherein an auxiliary hard resin layer (3) is further formed between the polishing layer (1) and the fastener support layer (2). The polishing pad according to claim 1, wherein the fastener support layer (2) has a thickness of 2 to 10 mm. 7. The polishing pad according to claim 6, wherein the auxiliary hard resin layer (3) has a hardness of 40 to 100 measured by a durometer hardness meter D-type (Type). 7. The auxiliary hard resin layer 3 is composed of one resin selected from polyurethane resin, polypropylene resin, polytetrafluoroethylene resin, polyester resin, polyamide resin, melamine resin and epoxy resin. A polishing pad characterized by the above-mentioned. The polishing pad according to claim 1, wherein the fastening mechanism (F) is a bolt. The fastening mechanism support layer 2 is formed on the back surface of the polishing layer 1, and then the polishing layer and the fastener support layer 2 are successively drilled to form the fastening mechanism grooves 4 of the polishing pad. Manufacturing method. 12. The polishing layer (1) according to claim 11, wherein the polishing layer (1) is one pad selected from a pad in which a polymer elastomer is impregnated in a nonwoven fabric, a pad composed of only a polymer elastomer, and a pad in which a polymer elastomer layer is laminated on a pad in which a polymer elastomer is impregnated in a nonwoven fabric. Method for producing a polishing pad, characterized in that. 12. The method of manufacturing a polishing pad according to claim 11, wherein the polishing layer (1) is planarized before drilling the fastener support layer (2) formed on the rear surface thereof. 12. The method of claim 11, wherein the fastener support layer (2) has a thickness of 2 to 10 mm. 12. The method of claim 11, wherein the fastener support layer (2) is one selected from a hard resin layer and a metallic plate. 12. The method of claim 11, further comprising forming an auxiliary hard resin layer (3) between the abrasive layer (1) and the fastener support layer (2). The method of manufacturing a polishing pad according to claim 15 or 16, wherein the hard resin layer and the auxiliary hard resin layer 3 have a hardness of 40 to 100 measured by a durometer hardness meter D-type. . The hard resin layer and the auxiliary hard resin layer (3) according to claim 15 or 16 are made of a polyurethane resin, a polypropylene resin, a polytetrafluoroethylene resin, a polyester resin, a polyamide resin, a melamine resin and an epoxy resin. Method for producing a polishing pad, characterized in that consisting of one selected resin.

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