JP2002009025A - Polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad for mechanically flattening the surface of an insulating layer or metal wiring formed on a silicon substrate by which the polishing rate is high, the global level difference is small, dishing at the metal wiring is hard to occur, few scratches are caused and little dust is adhered. SOLUTION: The polishing pad has a construction in which a fiber and/or an intermingle element of fibers exhibiting an official moisture regain of 5% or more are dispersed in a matrix resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad, and more particularly to a polishing pad for polishing a semiconductor substrate.
Further, the present invention relates to a polishing pad that can be used for chemical mechanical polishing in a step of mechanically flattening the surface of an insulating layer formed on a semiconductor substrate such as silicon or the surface of metal wiring.

[0002]

2. Description of the Related Art Large-scale integrated circuits (LSIs) typified by semiconductor memories are becoming more and more highly integrated year by year, and accordingly, the technology for manufacturing large-scale integrated circuits is becoming denser.
Further, with the increase in the density, the number of stacked semiconductor device manufacturing locations has also increased. Due to the increase in the number of layers, unevenness of the main surface of the semiconductor wafer caused by stacking, which has not been a problem in the past, has become a problem. As a result, for example, Nikkei Microdevice July 1994 Issue 50
As described on page 57, a chemical mechanical polishing technique is used for the purpose of compensating for a lack of depth of focus at the time of exposure due to unevenness caused by laminating, or for improving wiring density by flattening a through-hole portion. The flattening of a semiconductor wafer that has been used has been studied.

In general, a chemical mechanical polishing apparatus comprises a polishing head for holding a semiconductor wafer as an object to be processed, a polishing pad for performing a polishing process on the object to be processed, and a polishing platen for holding the polishing pad. . Then, in the polishing process of the semiconductor wafer, the protruding portion of the layer on the surface of the semiconductor wafer is removed by moving the semiconductor wafer and the polishing pad relative to each other using a slurry composed of an abrasive and a chemical solution, thereby smoothing the layer on the wafer surface. It is to be. The polishing rate is substantially proportional to the relative speed and load between the semiconductor wafer and the polishing pad. Therefore, in order to uniformly polish each part of the semiconductor wafer, it is necessary to make the load applied to the semiconductor wafer uniform.

When polishing an insulating layer or the like formed on the main surface of a semiconductor wafer, if the polishing pad is soft, local flatness deteriorates. For this reason, a foamed polyurethane sheet having a Shore A hardness of 90 degrees or more is currently used (Japanese Patent Application Laid-Open No. Hei 8-500622).

[0005]

However, the high-hardness polyurethane foam pad has a problem that the degree of flatness is different in portions having different densities of irregularities such as an insulating layer, and a global step is generated. There is a problem that dishing occurs in a wide area (the center of the metal wiring is lower in height than the edge). In addition, abrasives are easily adsorbed and clogging occurs immediately,
During polishing, there is a problem that the surface layer of the pad is set and the polishing rate is reduced.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing pad for mechanically planarizing the surface of an insulating layer or a metal wiring formed on a silicon substrate, which has a high polishing rate and a global step. Is small, dishing in metal wiring is unlikely to occur, scratches do not occur,
An object of the present invention is to provide a polishing pad in which dust does not easily adhere.

[0007]

Means for Solving the Problems As means for solving the problems, the present invention has the following constitution. (1) A polishing pad, wherein fibers having an official moisture regain of 5% or more and / or fiber entangled bodies are dispersed in a matrix resin. (2) The polishing pad according to (1), wherein the fiber entangled body is a nonwoven fabric. (3) The polishing pad according to (2), wherein the nonwoven fabric is a paper containing cellulose as a main component. (4) The polishing pad according to (1), wherein the fiber entangled body is a woven fabric. (5) The polishing pad according to (1), wherein the fiber entangled body is a cotton cloth. (6) The polishing pad according to any one of (1) to (5), wherein the ratio of the diameter to the length of the fiber is 10 or more. (7) The polishing pad according to any one of (1) to (6), wherein the polishing pad has substantially no void. (8) The polishing pad according to any one of (1) to (7), wherein the flexural modulus is 0.5 GPa or more and 100 GPa or less. (9) The polishing pad according to any one of (1) to (8), wherein the polishing pad has a D hardness of 60 degrees or more. (10) The polishing pad according to any one of (1) to (9), wherein the polishing pad is a polishing pad for CMP.

[0008]

Embodiments of the present invention will be described below.

First, the official moisture content referred to in the present invention is defined as a dry weight of a fiber or a fiber entangled body dried at 50 ° C. in a nitrogen atmosphere for 24 hours and a dry weight of 65% relative humidity at 20 ° C. in an atmosphere.
The moisture absorption weight after time was evaluated, and (moisture absorption weight-dry weight) /
It is a moisture percentage obtained by a formula of dry weight × 100. By dispersing fibers and / or fiber entangled bodies having an official moisture content of 5% or more in the matrix resin, scratches and dust attached to the semiconductor wafer can be suppressed. Scratches are scratches on the wafer surface due to polishing debris or aggregates of slurry. The dust adhesion means that the abrasive grains of the slurry adhere to the semiconductor wafer. By dispersing fibers and / or fiber entangled bodies having an official moisture content of 5% or more, it has been found that these can be suppressed. Preferably, by dispersing fibers and / or fiber entangled bodies having an official moisture regain of 7% or more in the matrix resin, it is possible to suppress scratches and dust adhesion. It is preferable that the fiber or the fiber entangled body having the official moisture regain of 5% or more is insoluble in water, from the viewpoint of further suppressing the adhesion of scratches and dust. Water-insoluble means that a fiber or a fiber entangled body is dispersed in water having a weight
For 6 hours with stirring, and the obtained aqueous solution is 0.45 μm in pore size.
After filtration through a membrane filter of m, the weight of the water-soluble component contained in the filtered water is measured, indicating that the ratio of the water-soluble component is 30 wt% or less by dry weight. Specific examples of the material of the fiber or the fiber entangled body having an official moisture regain of 5% or more include a cellulosic polymer, an acrylic polymer, a vinyl polymer, an aramid polymer, an amide polymer, and a starch polymer. But not limited thereto.

The fiber according to the present invention has a shape in which the ratio of the maximum diameter of the cross section to the length is 10 or more, and the fiber diameter is 1 μm or more.
It is preferably not more than 00 μm. If it is smaller than 1 μm, the effect of suppressing dust and scratches is lost, and
If it is larger than m, the polishing rate decreases, and the flattening characteristics deteriorate. Even if this fiber is dispersed without entanglement,
It is possible to suppress scratches and dust adhesion. Further, by dispersing a sheet in which fibers are entangled, for example, a nonwoven fabric or a woven fabric, it is also possible to suppress scratches and to suppress dust adhesion. The non-woven fabric is preferably made of natural fibers such as paper and cotton containing cellulose as a main component. Among them, paper containing cellulose as a main component is preferable because it has a large effect on suppressing scratches and suppressing dust adhesion. Cotton, as woven cloth
Woven fabrics made of natural fibers such as silk and hemp are preferred, and among them, cotton fabrics are preferred because they are highly effective in suppressing scratching and in suppressing dust adhesion.

The matrix resin of the present invention includes polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polychlorotrifluoroethylene, polytetrafluoroethylene, polymethyl methacrylate, polystyrene, polycarbonate,
Examples include, but are not limited to, nylon 66, nylon 6, polyoxymethylene, polyurethane, phenol / formaldehyde, urea / formaldehyde, melamine / formaldehyde, polyester, epoxy, melamine, polysulfone, and the like. It is preferable that the hardness of the matrix resin is 60 degrees or more in D hardness because the flattening characteristics are good. In dispersing fibers and / or fiber entangled bodies having an official moisture regain of 5% or more in the matrix resin, it is preferable to disperse the fibers or fibers at or below the thermal decomposition temperature of the fibers or fiber entangled bodies in order to obtain a good polishing pad. A thermosetting resin is preferable as the matrix resin because it can be dispersed at a temperature lower than the thermal decomposition temperature. The thermosetting resin has a slight fluidity when heated, but is subsequently cured by a crosslinking reaction and the like, and examples thereof include a urea resin, a melamine resin, and a phenol resin. In addition, resins such as epoxy resins and unsaturated polyester resins, which have a relatively low molecular weight and have fluidity, are poured into a mold and cured by crosslinking. These resins can be cured at room temperature. By utilizing such thermosetting properties, a composite polishing pad in which fibers or / and fiber entangled bodies having an official moisture content of 5% or more are dispersed can be easily produced. The dispersion amount of the fiber and / or the fiber entangled body is 2
The content is preferably from 0% by weight to 80% by weight. If the content is less than 20% by weight, the effect of suppressing scratches and the effect of suppressing dust adhesion are low, which is not preferable. If it exceeds 80% by weight,
It is not preferable because the polishing pad becomes brittle.

It is preferable that the obtained polishing pad has substantially no voids because it has good flattening characteristics. The bending elastic modulus of the polishing pad is preferably 0.5 GPa or more because the flattening characteristics are good.
It is preferably at most 00 GPa in that the in-plane uniformity of the semiconductor wafer is good. It is preferable that the D hardness of the polishing pad be 60 degrees or more because the flattening characteristics are good.

The polishing pad obtained by the present invention can be used as a composite polishing pad by laminating it with a cushion sheet having cushioning properties. The semiconductor substrate has slightly larger undulations apart from local irregularities, and it is necessary to use a composite polishing pad with a cushion sheet laminated under a hard polishing pad (on the polishing platen side) as a layer to absorb this undulation. it can.

[0014] Using the polishing pad of the present invention, silica slurry, aluminum oxide slurry,
Using a cerium oxide-based slurry or the like, unevenness of an insulating film and unevenness of a metal wiring on a semiconductor wafer can be locally flattened, global steps can be reduced, and dishing can be suppressed. As a specific example of the slurry, "CAB-O-SPIRESE" for CMP manufactured by Cabot Corporation
SC-1 ", CMP" CAB-O-SPERSE "
SC-112 ”, CMP“ SEMI-SPERSE ”
AM100 ”, CMP“ SEMI-SPERSE A ”
M100C ”, CMP“ SEMI-SPERSE 1 ”
2 "for CMP" SEMI-SPERSE 25 ", C
"SEMI-SPERSE W2000" for MP, CM
For example, “SEMI-SPERSE WA-A400” for P may be used, but the present invention is not limited thereto.

The object of the polishing pad of the present invention is the surface of an insulating layer or a metal wiring formed on a semiconductor wafer. As the insulating layer, an interlayer insulating film of a metal wiring, a lower insulating film of a metal wiring, or the like. Examples of the shallow trench isolation used for element isolation include aluminum, tungsten, and copper, and structurally include damascene, dual damascene, and plug. When copper is used as the metal wiring, a barrier metal such as silicon nitride is also polished. At present, silicon oxide is mainly used as an insulating film, but a low dielectric constant insulating film is used due to a problem of delay time. The low-dielectric-constant insulating film is softer and more brittle than silicon oxide, but the polishing pad of the present invention can be polished in a state where scratches are relatively difficult to enter. In addition to a semiconductor wafer, it can be used for polishing magnetic heads, hard disks, liquid crystal displays, plasma display related members, sapphire, and the like.

The surface shape of the polishing pad of the present invention is used in a shape that a normal polishing pad can take, such as a grooved shape, a dimple shape, a spiral shape, and a concentric shape, in order to suppress the hydroplane phenomenon. The polishing pad is used in the form of a disk, but it may be used in the form of a belt depending on the type of polishing machine.

The polishing pad of the present invention is fixed to a polishing platen (platen) of a polishing machine. The wafer is fixed to a wafer holding sample stage (carrier) by a vacuum chuck method. The polishing platen is rotated, and the wafer holding sample table is rotated in the same direction, and pressed against the polishing pad. At this time, the slurry is supplied from a position where the slurry enters between the polishing pad and the semiconductor wafer. The rotation speed of the polishing platen is set at a linear speed of 2000 at the center position of the semiconductor wafer.
It is preferably in the range of ５5000 (cm / min).
When the linear velocity of the polishing platen is lower than 2000 (cm / min), the flattening rate becomes slow, which is not preferable. If the linear velocity of the polishing platen exceeds 5000 (cm / min), scratches are likely to occur, which is not preferable. The pressing pressure is
This is performed by controlling the force applied to the wafer holding sample table. A pressing pressure of 0.01 to 0.1 MPa is preferable because local flatness can be obtained. However, some polishing machines have also developed a high-speed, low-pressure platen system.
It is not impossible to use the polishing conditions other than the above polishing conditions.

The surface of the polishing pad of the present invention is usually dressed with a conditioner in which diamond abrasive grains are electrodeposited before polishing. As a method of dressing, it is possible to use either batch dressing performed before polishing or in-situ dressing performed simultaneously with polishing.

[0019]

The present invention will be described below in further detail with reference to examples. In this example, each characteristic was measured by the following method.

1. Measurement of D hardness: thickness 1.0 mm-1.
Samples within 5mm range (size is 1cm square or more)
Is placed on a flat surface having a surface hardness of 90 degrees or more in D hardness, and a durometer type D (actually, Kobunshi Keiki Co., Ltd.) conforming to JIS standard (hardness test) K6253.
5 points were measured using an “Asker D hardness tester” manufactured by Kabushiki Kaisha, and the average value was taken as the D hardness. The measurement was performed at room temperature.

2. Measurement of Dust Amount: The wafer surface with the thermal oxide film after polishing was washed with a polyvinyl alcohol sponge while sprinkling with pure water, and dried by blowing dry compressed air. After that, the wafer surface dust inspection apparatus (“WM-3”, manufactured by Topcon Corporation) was used to reduce the diameter to 0.
The number of surface dusts of 5 μm or more was measured.

3. Evaluation method of flexural modulus: width 10 mm,
A plate-shaped test sample having a thickness of 1 to 2 mm was prepared, and the edge span width was 22 mm, and the crosshead speed was the test thickness (mm)
/ 2 (mm / min) was evaluated using a Tensilon universal testing machine (“RTM-100” manufactured by Orientec Co., Ltd.).

4. Test wafer for global level difference evaluation:
4-inch silicon wafer with oxide film (oxide film thickness: 2μ)
m), a 10 mm square die is arranged. Perform a mask exposure using photoresist and 10m by RIE.
A line of 20 μm width and height of 0.7 μm and a space of 230 μm are arranged on the left half in a m-square die in a line and space, and a line of 230 μm width and height of 0.7 μm is placed on the right half with a space of 20 μm. Arrange in line and space. Thus, a test wafer for global step evaluation was prepared.

5. Test wafer for dishing evaluation of tungsten wiring: 4-inch silicon wafer with oxide film (oxide film thickness: 2 μm), 100 μm width and 0.7 μ depth
m grooves are formed at intervals of 100 μm. A tungsten film having a thickness of 2 μm was formed thereon by sputtering to prepare a test wafer for evaluating dishing of tungsten wiring.

6. Polishing pad and polishing machine: 1.2m thickness
A circular polishing layer having a diameter of 38 m and a diameter of 38 cm was prepared, and the surface was subjected to so-called XY groove processing (grid-like groove processing) having a width of 2.0 mm, a depth of 0.5 mm, and a pitch of 15 mm. This polishing pad was polished with a polishing machine (Lapmaster SFT “L /
As a cushion layer, "Suba400" manufactured by Rodale Co., Ltd. was adhered to the surface plate of "M-15E"), and a double-sided adhesive tape ("442J" manufactured by 3M) was adhered thereon. Conditioner manufactured by Asahi Diamond Industry Co., Ltd. ("CMP-
M ", diameter 14.2 cm) and a pressing pressure of 0.0
4MPa, rotated in the same direction at a platen rotation speed of 25rpm and a conditioner rotation speed of 25rpm.
The polishing pad was conditioned for 5 minutes while being supplied in minutes. The polishing pad was washed for 2 minutes while flowing 100 cc / min of pure water through the polishing machine. Then, a test wafer for evaluating a global level difference was set on the polishing machine, and a slurry manufactured by Cabot Corporation (“SC-1”) having a concentration described in the instruction manual was used. ) Is supplied on the polishing pad at a predetermined supply amount, and a pressing pressure of 0.0
Polishing was carried out for a predetermined time by rotating the semiconductor wafer holding sample stage in the same direction at a rotation speed of 45 rpm at 4 MPa, a rotation speed of the platen of 45 rpm (linear velocity at the center of the wafer is 3000 (cm / min)). The surface of the semiconductor wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. The oxide film thickness of the 20 μm line and the 230 μm line in the center 10 mm die of the test wafer for global level difference evaluation was measured using Lambda Ace (“VM-2000”) manufactured by Dainippon Screen Co., Ltd. Was evaluated. Further, the same conditioning as above was performed, and a test wafer for evaluating tungsten wiring dishing was set on a polishing machine, and a slurry manufactured by Cabot Corporation (“SEMI-SP
ERSE WA-A400 ”) and Cabot oxidizer (“ SEMI-SPERSE FE-400 ”):
While supplying the slurry solution mixed in Step 1 with a predetermined supply amount onto the polishing pad, the pressing pressure is 0.04 MPa and the platen rotation speed is 45 rpm (the linear velocity at the center of the wafer is 3000).
(Cm / min)), the sample stage holding the semiconductor wafer was rotated at 45 rpm.
It was rotated in the same direction at rpm and polished for a predetermined time.
The surface of the semiconductor wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. The dishing state of the tungsten surface was measured with an ultra-depth shape measuring microscope “VK-8500” manufactured by Keyence Corporation.

7. The presence / absence of a void was observed with a digital microscope “VH-6300” manufactured by KEYENCE CORPORATION at 100 to 500 times the cross section of the polishing pad. The ratio between the diameter and the length of the fiber was also observed with "VH-6300".

Example 1 A liquid phenol resin (manufactured by Sumitomo Durez, "PR-531")
23 ″) 100 parts by weight of linter paper 1 having a thickness of 300 μm
A prepreg is prepared by impregnating 00 parts by weight. Five prepregs are stacked and heated and compressed at 150 ° C. to form a phenolic resin / paper laminate. Using this laminate, a polishing pad having a thickness of 1.2 mm was prepared. The official moisture regain of the paper was 11%. A cushion layer “Suba400” was bonded to the polishing pad to produce a composite polishing pad. The test wafer for global level difference evaluation was attached to a polishing head of a polishing machine and rotated at 45 rpm. The composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head to obtain slurry “S”.
While supplying C-1 ″ at 100 cc / min, the polishing pressure was set at 0.
Polishing was performed at 04 MPa. The global step between the 20 μm-wide wiring region and the 230 μm-wide wiring region of the test wafer for global level difference evaluation was 0.2 μm. The polishing time was 4 hours.
Minutes. In addition, the test wafer for dishing evaluation of tungsten wiring was attached to the polishing head of
The composite polishing pad is fixed to a platen of a polishing machine by rotating at 5 rpm, and rotated in the same direction as the rotation direction of the polishing head at 45 rpm, and a polishing pressure of 0.04 is supplied while supplying Cabot tungsten slurry at 100 cc / min.
Polishing was performed at MPa. The dishing depth at the center of the tungsten wiring (100 μm width) when the oxide film surface was exposed was 0.03 μm. The amount of dust attached to the wafer having a 4-inch oxide film was 120, and no scratch was observed. The D hardness of the polishing pad was 70 degrees. The flexural modulus was 5 GPa. There were no substantial voids in the polishing pad. The ratio of the fiber diameter to the length of the linter paper used was 10 or more at any observation site.

Example 2 100 parts by weight of a mixed solution of 100 parts by weight of "Epicoat 190" (manufactured by Yuka Shell Epoxy Co., Ltd.) and 100 parts by weight of hexahydrophthalic anhydride as an epoxy main agent were impregnated into 100 parts by weight of kraft paper having a thickness of 200 μm. To create a prepreg. Seven prepregs are stacked and heated and compressed at 160 ° C. to prepare an epoxy resin / paper laminate. Using this laminated plate, a polishing pad having a thickness of 1.2 mm was prepared. The official moisture regain of the paper was 11%. Cushion layer “Suba4
00 "was attached to the polishing pad to prepare a composite polishing pad. A test wafer for global step evaluation was attached to a polishing head of a polishing machine and rotated at 45 rpm to fix the composite polishing pad to a platen of the polishing machine. 45 rp
m, the polishing head was rotated in the same direction as the rotation direction of the polishing head, and polishing was performed at a polishing pressure of 0.04 MPa while supplying the slurry “SC-1” at 100 cc / min. 20 μm wide wiring area and 230 μm of global level difference test wafer
The polishing time when the global step in the width wiring region became 0.2 μm was 4 minutes. Further, the test wafer for evaluating the tungsten wiring dishing was attached to a polishing head of a polishing machine and rotated at 45 rpm, the composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head. Polishing was carried out at a polishing pressure of 0.04 MPa while supplying a slurry for tungsten manufactured at 100 cc / min. The dishing depth at the center of the tungsten wiring (100 μm width) when the oxide film surface was exposed was 0.03 μm. The amount of dust adhering to the wafer having a 4-inch oxide film was 120, and no scratch was observed. The polishing pad had a D hardness of 64 degrees and a flexural modulus of 10 GPa.

Example 3 0.1 parts by weight of azobisisobutyronitrile was added to 100 parts by weight of methyl methacrylate, and a fiber obtained by spinning Indian cotton was impregnated into a plain-woven cotton cloth, sandwiched between glass plates, and polymerized between plates. Was done. The thickness of the obtained polishing pad was 1.2 mm. The official moisture regain of the cotton cloth was 7%. A cushion layer “Suba400” was bonded to the polishing pad to produce a composite polishing pad. The test wafer for global level difference evaluation was attached to a polishing head of a polishing machine and rotated at 45 rpm, the composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head to obtain a slurry “SC- 1 "to 10
Polishing was performed at a polishing pressure of 0.04 MPa while supplying at 0 cc / min. Test wafer for global level difference evaluation 2
The global step between the 0 μm width wiring region and the 230 μm width wiring region became 0.2 μm, and the polishing time was 4 minutes. Further, a test wafer for evaluating tungsten wiring dishing was attached to a polishing head of a polishing machine and rotated at 45 rpm, and the composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head. 100c of tungsten slurry
Polishing was performed at a polishing pressure of 0.04 MPa while supplying at c / min. The dishing depth at the center of the tungsten wiring (100 μm width) when the oxide film surface is exposed is 0.03
μm. The amount of dust attached to the wafer having a 4-inch oxide film was 120, and no scratch was observed. The polishing pad had a D hardness of 70 degrees and a flexural modulus of 40 GPa. There were no substantial voids in the polishing pad. The ratio between the diameter and the length of the fibers of the cotton cloth used was 10 or more at any observation place.

Comparative Example 1 Liquid phenolic resin (PR-5312, manufactured by Sumitomo Durez)
3) A polishing pad having a thickness of 1.2 mm was prepared by impregnating 70 parts by weight with a nylon 6 cloth in which nylon 6 fibers having a diameter of 10 μm were plain-woven. The official moisture regain of nylon 6 cloth was 4%. A cushion layer “Suba400” was bonded to the polishing pad to produce a composite polishing pad. The test wafer for global level difference evaluation was attached to a polishing head of a polishing machine and rotated at 45 rpm, the composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head to obtain a slurry “SC- 1 "to 1
Polishing was performed at a polishing pressure of 0.04 MPa while supplying at a rate of 00 cc / min. The global step between the 20 μm-wide wiring region and the 230 μm-wide wiring region of the test wafer for global step evaluation became 0.2 μm, and the polishing time was 7 minutes.
Further, a test wafer for evaluating tungsten wiring dishing was attached to a polishing head of a polishing machine and rotated at 45 rpm, and the composite polishing pad was fixed to a platen of the polishing machine, and rotated at 45 rpm in the same direction as the rotation direction of the polishing head. 100% tungsten slurry
Polishing was performed at a polishing pressure of 0.04 MPa while supplying at a rate of cc / min. The dishing depth at the center of the tungsten wiring (100 μm width) when the oxide film surface is exposed is 0.1
It was 3 μm. The amount of dust attached to the wafer having a 4-inch oxide film was 600, and scratches were observed. The polishing pad had a D hardness of 62 degrees and a flexural modulus of 5 GPa. There were no substantial voids in the polishing pad. The ratio between the diameter and the length of the nylon 6 fiber used was 10 or more at any observation place.

[0031]

According to the present invention, it is possible to provide a polishing pad which has a high polishing rate, a small global level difference, hardly causes dishing in metal wiring, does not generate scratches, and hardly causes dust adhesion.

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference)

Claims (10)

[Claims] 1. A polishing pad characterized in that fibers and / or fiber entangled bodies having an official moisture content of 5% or more are dispersed in a matrix resin. 2. The polishing pad according to claim 1, wherein the fiber entangled body is a non-woven fabric. 3. The polishing pad according to claim 2, wherein the nonwoven fabric is a paper containing cellulose as a main component. 4. The polishing pad according to claim 1, wherein the fiber entangled body is a woven fabric. 5. The polishing pad according to claim 1, wherein the fiber entangled body is a cotton cloth. 6. The polishing pad according to claim 1, wherein a ratio between a diameter and a length of the fiber is 10 or more. 7. The polishing pad according to claim 1, wherein the polishing pad has substantially no void. 8. A flexural modulus of not less than 0.5 GPa and not more than 100 GPa.
The polishing pad according to claim 1, wherein a is equal to or less than a. 9. The polishing pad according to claim 1, wherein the polishing pad has a D hardness of 60 degrees or more. 10. The polishing pad according to claim 1, wherein the polishing pad is a polishing pad for CMP.