JP2002059357A - Polishing pad, polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad, a polishing device and a polishing method capable of speedily eliminating a global step difference by selectively polishing a protruded part of an irregularity on a semiconductor substrate surface in flattening of the semiconductor substrate by a CMP, reducing recessing quantity of dishing and thinning even in polishing in metallic wiring and an STI and providing the high quality semiconductor substrate with few scratch flaws and residual dust. SOLUTION: The polishing pad to be used for chemical mechanical polishing to flatten the substrate constitutes its characteristic feature of containing a polishing layer a contact angle with water of which is less than 75 degrees and to satisfy conditions of (A) and/or (B) shown hereinunder. (A) A flexural elastic modulus is more than 2 GPa. (B) Surface hardness is more than 80 in durometer D hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad, a polishing apparatus, and a polishing method used for chemical mechanical polishing of a semiconductor substrate, a glass substrate, and the like, and more particularly, to an interlayer formed on a semiconductor substrate. The present invention relates to a polishing pad, a polishing apparatus, and a polishing method used for chemical mechanical polishing for planarizing an insulating film, planarizing a metal wiring buried in a groove, or planarizing an oxide film buried in a groove. .

[0002]

2. Description of the Related Art As the performance of semiconductor devices has been improved, fine transistors and wiring electrodes connecting them have been arranged and designed at high density at random, and wirings have also become multilayered. Since the insulating film (oxide film) formed between the layers of the multilayer wiring covers these wiring electrodes,
The surface of the interlayer insulating film has irregularities in a random, dense and dense pattern. As a result, for example, as described in Nikkei Microdevices, July, 1994, pages 50 to 57, the depth of focus at the time of exposure in the lithography process occurs due to the unevenness of the surface of the interlayer insulating film. Therefore, it is necessary to flatten the unevenness on the surface of the interlayer insulating film, and a chemical mechanical polishing (CMP: Chemical Mechanical) is required.
2. Description of the Related Art Flattening of a semiconductor substrate by polishing has been adopted in a manufacturing process of a semiconductor device.

As the technology for planarizing the surface of an interlayer insulating film by CMP has deepened, the CMP technology has also been used for the damascene process for forming metal wiring and the planarization in shallow trench isolation (STI) for element isolation. It is being applied. In the damascene process, tungsten (W) buried in a wiring groove formed in an interlayer insulating film is used.
Polishing an excess portion of metal wiring such as aluminum, aluminum (Al), and copper (Cu) to planarize the surface of the metal wiring has been studied. In STI, an excess portion of an oxide film buried in a groove formed in a silicon (Si) substrate in which a silicon nitride (Si ₃ N ₄ ) film is patterned as a stopper film is polished to planarize the oxide film surface. It is also under consideration to do so.

At present, in a semiconductor device manufacturing process, a polishing pad used for flattening a semiconductor substrate includes a polishing layer and a semiconductor which participate in actual polishing as disclosed in Japanese Patent Application Laid-Open No. Hei 6-21028. The mainstream is a two-layer pad in which a cushion layer is bonded to follow the undulation of the substrate. In particular, a polishing layer (“IC-1000”) and a cushion layer (“Suba400”) manufactured by Rodale in the United States are bonded. Tailored polishing pads are widely and commonly used. The polishing layer, “IC-1000”, is described in
As described in US Pat. No. 5,062, it is made of a rigid polyurethane having a foamed structure.

[0005]

A polishing layer made of a rigid polyurethane having a foamed structure, which is widely used at present, has a surface hardness of about 60 in durometer D hardness and a flexural modulus of about 0.3 GPa, which is a polyurethane. Although it belongs to a hard class, it can be said that the polishing layer is in a relatively soft class when viewed from the whole resin. For this reason, in the uneven pattern having a rough and dense surface on the surface of the interlayer insulating film, not only the convex portions but also the relatively wide concave portions are polished, and there is a problem that a step (global step) in the chip is hardly eliminated. Therefore, in practical use, before obtaining sufficient flatness, a thick interlayer insulating film is formed to prevent the underlying metal wiring from being exposed by polishing.Furthermore, a dummy wiring is formed in a wide recess to polish the recess. Measures have been taken to prevent this from happening. However, the thicker the interlayer insulating film, the longer the time required for polishing,
Accordingly, there is a problem that the cost of the polishing process is increased, and the formation of the dummy wiring imposes restrictions on the wiring design. Further, in the polishing of a metal wiring in a damascene process or the polishing of an oxide film in STI, a depression (dishing) occurs due to excessive polishing in a wide portion of a groove, and furthermore, excessive polishing occurs in a wiring portion in which grooves are densely formed. There are problems such as generation of dents (thinning).

[0006] In order to solve the above-mentioned problems and realize more accurate flattening, a polishing layer made of a harder resin has been studied. As such a polishing layer, a vinyl chloride (PVC) resin plate or polymethyl methacrylate (PM
MA) A hard polishing layer such as a resin plate having a surface hardness of 80 or more in durometer D hardness and a flexural modulus of 2 GPa or more has been studied. However, the harder the polishing layer, the more scratches are generated on the semiconductor substrate, and more dust is left on the semiconductor substrate. Was.

[0007] Therefore, we have studied diligently to improve the quality of the semiconductor substrate surface by suppressing scratches and residual dust in the polishing layer made of a harder resin. Was found to be related to scratches and residual dust, and it was possible to reduce these by improving water wettability, leading to the present invention.

That is, the present invention solves the above-mentioned problems by using a polishing layer that is harder and has better water wettability, that is, a smaller contact angle with water. The global step can be eliminated quickly by selectively polishing the projections of the unevenness on the substrate surface, and the amount of dents such as dishing and thinning is small in polishing of metal wiring and STI, and there are few scratches and residual dust. An object of the present invention is to provide a polishing pad, a polishing apparatus, and a polishing method capable of obtaining a high-quality semiconductor substrate.

[0009]

Means for Solving the Problems As means for solving the problems, the present invention has the following constitution. That is, (1) In a polishing pad used for chemical mechanical polishing for flattening a substrate, a contact angle with water is 75 degrees or less, and (A) and / or (B) shown below A polishing pad comprising a polishing layer satisfying requirements.

(A) The flexural modulus is 2 GPa or more. (B) The surface hardness is 80 or more in durometer D hardness. (2) The substrate is a semiconductor substrate having an interlayer insulating film formed on the substrate, The polishing pad according to (1), wherein the film is polished and removed to planarize the surface of the interlayer insulating film.

(3) The substrate is a semiconductor substrate in which a metal wiring whose main component is one of Cu, Al and W is embedded in a wiring groove formed on the substrate, and an unnecessary portion of the metal wiring is provided. The polishing pad according to (1), wherein the polishing pad is removed by polishing to flatten the surface of the metal wiring.

(4) The substrate is a semiconductor substrate in which an oxide film is buried in a groove formed on the substrate, and unnecessary portions of the oxide film are polished and removed to flatten the surface of the oxide film. The polishing pad according to the above (1), which is a polishing pad.

(5) The polishing layer according to the above (1), wherein the polishing layer comprises a paper and / or cloth base laminate.
The polishing pad according to any one of (4).

(6) The polishing pad is obtained by laminating the polishing layer described in (1) above and a cushion layer having a bulk modulus of 60 MPa or more and a tensile modulus of 0.1 MPa to 20 MPa. The polishing pad according to any one of the above (1) to (5).

(7) The polishing pad according to any one of (1) to (6), wherein a groove or a hole is formed on a surface of the polishing layer.

(8) A polishing head, the polishing pad according to any one of claims 1 to 7, which is arranged to face the polishing head, a polishing platen for fixing the polishing pad, the polishing head, And / or a driving device for rotating the polishing platen.

(9) The substrate is fixed to a polishing head, and the polishing head and / or polishing is performed with the polishing pad according to any one of claims 1 to 7 pressed against the substrate fixed to a polishing platen. A polishing method characterized by polishing a substrate by rotating a surface plate.

[0018]

Embodiments of the present invention will be described below.

The substrate according to the present invention includes a silicon bare wafer and a semiconductor substrate on which elements and wirings are formed,
Glass substrates for flat displays such as liquid crystal displays, TFT substrates, back plates for plasma displays, etc.
The polishing pad of the present invention is not particularly limited as long as it can be polished by CMP. However, the polishing pad of the present invention is suitably used for polishing a semiconductor substrate, and an oxide film or an interlayer insulating film made of a low dielectric constant material has a main component. It is suitable for polishing wiring formed of a metal such as Cu, Al, and W, and an oxide film formed for element isolation.

The polishing pad of the present invention can be used alone as a polishing layer, but is more preferably a two-layer pad in which a polishing layer and a cushion layer are bonded.

In the planarization of a semiconductor substrate by CMP, it is preferable that the polishing layer has high rigidity in order to suppress polishing of the concave portions of the unevenness on the substrate surface and selectively polish only the convex portions. The flexural modulus is preferably 2 GPa or more, but more preferably 5 to 20 GPa in order to achieve more accurate flattening. The bending elastic modulus of the polishing layer is measured by a bending test method for hard plastics described in JIS K7203.
Further, the hardness of the polishing layer is preferably 80 or more in durometer D hardness, and more preferably 85 to 97 in order to realize more accurate flattening. The durometer D hardness of the polishing layer is measured by a durometer hardness test method for hard plastics described in JIS K7215.

In planarizing a semiconductor substrate by CMP, in order to suppress scratches and residual dust on the substrate surface, it is preferable that the polishing layer surface has good water wettability during polishing. The contact angle of the layer surface with water is preferably 75 degrees or less, and more preferably 0 to 60 degrees for a higher quality substrate surface. The contact angle of the polishing layer surface with water is measured by using a commercially available contact angle meter by any one of a droplet method, a tilt method, and a falling method. The surface of the polishing layer referred to here is a surface that comes into contact with the semiconductor substrate via the abrasive slurry as an abrasive, and does not include grooves or holes formed by processing the polishing layer described later.

Here, before the semiconductor substrate is polished in advance, the surface of the polishing layer is generally subjected to an operation of roughening the surface of the polishing layer using a dresser, that is, so-called dressing, so that good polishing characteristics are obtained. It is preferably implemented for The dresser is a wheel in which diamond abrasive grains are electrodeposited and fixed, for example, a dresser model name CMP-M or C of Asahi Diamond Industrial Co., Ltd.
Specific examples include MP-N and CMP-L. The particle size of the diamond abrasive can be selected in the range of 10 μm to 400 μm. The pressing pressure of the dresser is arbitrarily selected in the range of 0.005 MPa to 0.2 MPa. Further, dressing the polishing pad with a dresser after one or more polishing operations is preferably performed to stabilize the polishing rate. As for the roughness of the polishing layer surface after dressing, the center line average roughness Ra is preferably 2 to 20 μm, and more preferably 3 to 7 μm. The ten-point average roughness Rz is preferably from 10 to 300 μm, and more preferably from 20 to 100 μm. By dressing the surface of the polishing layer before polishing, the lubricating state between the semiconductor substrate and the polishing layer can be favorably maintained via the abrasive slurry as the polishing agent, and a high polishing rate can be stably obtained. The center line average roughness Ra and the ten-point average roughness Rz are measured using a stylus type surface roughness measuring device described in JIS B0651.

The contact angle of the polishing layer surface with water as referred to in the present invention means the contact angle of the polishing layer surface with water during polishing, that is, the contact angle of the dressed polishing layer surface. It is known that the contact angle varies not only with the chemical properties of the material but also with the micromorphology of the material surface. Therefore, the contact angle in the present invention is a value obtained by measuring the contact angle of the polishing layer surface with water having a center line average roughness Ra of 3 to 7 μm by dressing.

The polishing layer of the present invention has a flexural modulus and / or a durometer D hardness, that is, a flexural modulus or a durometer D hardness, or both a flexural modulus and a durometer D hardness within the above range, and after the dressing. The material is not particularly limited as long as the material has a contact angle with water within the above range. It is presumed that a water swelling layer is present on the outermost surface of the polishing layer having a contact angle with water of 75 degrees or less, thereby suppressing scratches and residual dust. For this reason, it is preferable that the material be such that the bending elastic modulus and / or durometer D hardness of the polishing layer maintain the above range even when water is absorbed.

As such a polishing layer, 2 having different physical properties are used.
A polishing layer composed of a composite material of at least two or more kinds of materials is preferable. Examples of such a material include a paper and / or cloth base laminate, or a resin composition in which a water-insoluble hydrophilic component is dispersed in a hard matrix resin. It is preferably used. Further, a hard resin composition containing a small amount of a hydrophilic group is also preferably used.

As the paper and / or cloth base laminate,
For paper made of natural fibers such as kraft paper and linter paper, or base material such as cloth made of natural fibers such as cotton and silk,
A varnish in which the resin is dissolved is impregnated, and then the solvent is removed by drying to obtain a prepreg, and a laminate obtained by laminating one or more prepregs and pressurizing and heating with a press machine is preferably used. Here, the resin is a phenolic resin,
A thermosetting resin such as an epoxy resin, a polyimide resin, a melamine resin, an unsaturated polyester resin, a urea resin, a xylene resin, and a furan resin can be used. Among them, a phenol resin and an epoxy resin are more preferably used.

As the resin composition in which a hydrophilic component is dispersed in a hard matrix resin, a thermosetting resin such as an epoxy resin or a thermoplastic resin such as polymethyl methacrylate (PMMA) is used as a hard matrix resin, and a cellulose cellulose powder is used. A resin composition in which a water-insoluble hydrophilic component such as a crosslinked hydrophilic resin powder is dispersed is preferably used.

The thickness of the polishing layer of the present invention is not particularly limited, but is preferably 0.2 to 30 mm.
It is more preferably 0.3 to 10 mm, and still more preferably 0.5 to 3 mm. If the thickness is too thin, the mechanical properties of the polishing layer, which is located below the cushion layer or the lower layer preferably used as the base of the polishing layer, are more significantly reflected in the polishing properties than the mechanical properties of the polishing layer itself. On the other hand, if the thickness is too large, the mechanical properties of the cushion layer will not be reflected, and the followability of the semiconductor substrate to the undulation will be reduced, and the flatness of the entire substrate will not be uniform.

The polishing layer of the present invention is preferably provided with grooves or holes on the surface for the purpose of promoting the supply of the polishing agent to the polishing surface in contact with the semiconductor substrate and the discharge thereof therefrom. . As the shape of the groove, various shapes such as concentric circles, spirals, radiation, and grids can be adopted. As the cross-sectional shape of the groove, a shape such as a square, a triangle, and a semicircle can be preferably adopted.
The depth of the groove, the width of the groove, the pitch of the groove is not particularly limited, but the depth ranges from 0.1 mm to the thickness of the polishing layer, the width ranges from 0.1 to 20 mm, The pitch is 2
A range of 200 mm is preferred. The holes may or may not penetrate the polishing layer. The diameter of the holes and the pitch of the holes are not particularly limited, but the diameter is 0.2
In the range of ２０20 mm, the pitch is preferably in the range of 2１００100 mm.

The cushion layer used in the polishing pad of the present invention is made of a polyurethane-impregnated nonwoven fabric (for example, Suba40 manufactured by Rodale Co., Ltd.) which is currently widely used.
0, etc.), rubber, foamed elastic body, foamed plastic, and the like can be adopted, and are not particularly limited, but have a bulk modulus of 60 MPa or more and a tensile modulus of 0.1 to 20 MPa. A cushion layer having properties is preferred. If the tensile modulus is low, the uniformity of the flatness over the entire surface of the semiconductor substrate tends to be impaired. Even when the tensile modulus is large, the uniformity of the flatness over the entire surface of the semiconductor substrate tends to be impaired. A more preferred range of tensile modulus is
0.5 to 10 MPa.

Here, the term "bulk elastic modulus" refers to a change in volume of an object whose volume has been measured in advance by applying an isotropic applied pressure to the measured object. It is defined as bulk modulus = applied pressure / (volume change / original volume). For example, if the original volume is 1
cm ³ , and isotropically applied pressure of 0.07MP
If the change in volume when a is applied is 0.00005 cm ³ , the bulk modulus is 1400 MPa. As one method of measuring the bulk modulus, for example, the volume of an object to be measured is measured in advance, then the object to be measured is immersed in water placed in a container, the container is placed in a pressure vessel, and the applied pressure is increased. In addition, there is a method of measuring a change in the volume of an object to be measured and an applied pressure from a change in the height of water in the inner container. The liquid to be immersed is preferably one that does not swell or destroy the object to be measured, and is not particularly limited as long as it is a liquid, and examples thereof include water, mercury, and silicon oil.
The tensile modulus is determined by applying a tensile stress to a cushion layer in a dumbbell shape and applying a tensile strain (= change in tensile length /
Tensile stress was measured in the range of 0.01 to 0.03 of the original length, and the tensile modulus = (((tensile strain was 0.03 to 0.03)).
Tensile stress at the time) − (tensile stress at a tensile strain of 0.01)) / 0.02.

Rubber is an example of a component constituting the cushion layer having such characteristics. Specific examples include natural rubber, nitrile rubber, neoprene (registered trademark) rubber, polybutadiene rubber, polyurethane rubber, and silicone rubber. Foaming elastomers can be mentioned, but not particularly limited to these. The preferred thickness of the cushion layer is in the range of 0.1 to 100 mm. If the thickness is small, the uniformity of the flatness over the entire surface of the semiconductor substrate (uniformity) tends to be impaired. Conversely, when the thickness is large, local flatness tends to be impaired. A more preferable range of the thickness is 0.2 to 5 mm. A more preferred range is 0.5 to 2 mm.

The polishing pad of the present invention is used by being fixed to a polishing platen. At that time, it is important to fix the cushion layer from the polishing platen so as not to shift during polishing, and to fix the polishing layer so as not to shift from the cushion layer. Examples of the method of fixing the polishing platen and the cushion layer include a method of fixing with a double-sided adhesive tape, a method of fixing with an adhesive, and a method of fixing the cushion layer by suctioning from the polishing platen, but are particularly limited. is not. As a method of fixing the cushion layer and the polishing layer, a method of fixing with a double-sided adhesive tape, a method of fixing with an adhesive, and the like can be considered, but are not particularly limited.

The preferred double-sided adhesive tape or adhesive layer for bonding the polishing layer and the cushion layer is Sumitomo 3
Double-sided adhesive tapes 463, 465 and 920 of M Corporation
No. 4, double-sided adhesive tape No. of Nitto Denko Corporation. Acrylic adhesive transfer tape without base material such as 591, Sumitomo 3M
Specific examples thereof include a double-sided adhesive tape based on a foamed sheet such as Y-4913 and a soft vinyl chloride-based base such as 447DL from Sumitomo 3M.

In the present invention, when it is necessary to replace the polishing layer after polishing because the polishing rate cannot be obtained, the polishing layer is removed from the cushion layer with the cushion layer fixed to the polishing platen. It is also possible to exchange. Since the cushion layer is more durable than the polishing layer,
Replacing only the polishing layer is preferable in terms of cost.

Hereinafter, a method for polishing a semiconductor substrate by CMP using the polishing pad of the present invention will be described.

Using the polishing pad of the present invention, a polishing agent such as a silica polishing agent, an aluminum oxide polishing agent, or a cerium oxide polishing agent is used as a polishing agent. The unevenness of the wiring can be flattened.

First, a polishing apparatus having a polishing head for fixing a substrate, a polishing platen for fixing a polishing pad, and a means for rotating the polishing head and / or the polishing platen is prepared. Then, the polishing pad of the present invention is fixed to a polishing platen of a polishing apparatus such that the polishing layer faces the polishing head. The semiconductor substrate is fixed to the polishing head by a method such as a vacuum chuck. The polishing table is rotated, and the polishing head is rotated in the same direction as the rotation of the polishing table, and pressed against the polishing pad. At this time, the polishing agent is supplied from a position where the polishing agent enters between the polishing pad and the semiconductor substrate. The pressing pressure is usually performed by controlling the force applied to the polishing head. A pressure of 0.01 to 0.2 MPa is preferable because good flatness can be obtained.

[0040]

The present invention will be described below in further detail with reference to examples.

Here, the flexural modulus, durometer D hardness, surface roughness, and contact angle of the polishing layer were measured by the following methods.

(Flexural Modulus) Using a material tester (Tensilon RTM-100) manufactured by ORIENTEC, JI
It was measured according to the bending test method of hard plastic described in SK7203. The measurement was performed five times, and the average value was obtained. (Durometer D hardness) Using a durometer D hardness meter manufactured by Kobunshi Keiki Co., Ltd., it was measured according to the durometer hardness test method for hard plastics described in JIS K7215. The measurement is performed by stacking two polishing layers and making the thickness 2 mm or more.
Measurements were made at 10 points in the polishing layer, and the average value was obtained.

(Surface Roughness) Kosaka Labora
tory Inc. Surface Roughness Tester (Surfcorde
r SE-3300). Measurement conditions are J
According to the surface roughness described in IS B0601, cut-off value λc 0.8 mm, measured length L 8 mm, speed 0.1 m
m / s was adopted. For the measurement, the center line average roughness Ra and the ten-point average roughness Rz were measured at 10 points in the dressed polishing layer, and the respective average values were obtained.

(Contact Angle) Using a contact angle meter (CA-D type) manufactured by Kyowa Interface Science Co., Ltd., the contact angle of the polishing layer, which was dressed and then naturally dried, with water was measured 10 times by a droplet method. Then, the average value was obtained.

The CMP polishing evaluation of the semiconductor substrate was performed by the following method, and the polishing rate, the number of scratches, the number of remaining dusts, and the global flatness were measured.

(CMP of Solid Oxide Film)
A 4-inch silicon wafer with a thermal oxide film having a thickness of 1 μm was polished using a 15LE type polishing machine (polishing plate diameter φ38 cm) manufactured by R Company. The abrasive slurry used was "CAB-O-SPERSE SC-1" manufactured by Cabot Corporation diluted three times with ultrapure water. Wafer is a packing film made by Rodale (T / P1
20-41CF22SJ) and fixed to a polishing head. The polishing pad is a double-sided adhesive tape (Sumitomo 3M Co., Ltd. type 4)
42J) and fixed to a polishing platen. The polishing layer was used for polishing evaluation after the surface was dressed using a dresser (model CMP-M) manufactured by Asahi Diamond Co., Ltd.
The dressing conditions were a pressure of 400 g / cm ² , a rotation speed of the polishing head and the polishing table of 30 rpm, and a supply amount of ultrapure water of 10 rpm.
ml / min, dressing time 5 minutes. After the dressing, the surface of the polishing layer was washed with a nylon brush under running ultrapure water and subjected to polishing. The polishing conditions were a pressure of 400 g / cm ² ,
The polishing was performed at a rotation speed of the polishing head and the polishing platen of 50 rpm, a supply amount of the abrasive slurry of 100 ml / min, and a polishing time of 5 minutes. The polished wafer was washed with a polyvinyl alcohol cloth under running ultrapure water, and water on the wafer surface was removed with compressed air. The polishing speed was measured by using a film thickness meter (Lambda Ace VM-2000) manufactured by Dainippon Screen Co., Ltd. to measure the oxide film thickness before and after polishing at 196 points in the wafer surface (5 mm pitch grid, 10 mm from the edge not measured). The polishing rate was determined from the average of the differences. The number of scratches on the wafer surface after polishing was counted with a digital microscope (VH6300, manufactured by Keyence Corporation) equipped with an automatic XY stage, and the number of residual dusts was counted with a dust inspection device manufactured by Topcon. The semiconductor substrate was considered to be of high quality when the number of scratches was 10 / wafer or less and the number of remaining dusts was 250 / wafer or less.

(CMP of Oxide Film with Concavo-convex Pattern) FIG. 1
Polishing was performed in the same procedure as above using a 4-inch silicon wafer provided with an oxide film in which chips of 10 mm square having 25 kinds of coverage as shown in FIG. The coverage is 92% (projection width 230 μm, depression width 20
μm) with a coverage of 8% (projection width 20 μm, depression width 23)
(0 μm) as a global step (the initial step is about 0.45 μm), and when the polishing time is less than 4 minutes and the global step is reduced to 0.3 μm or less, the flatness is determined to be good. . Further, when the global step is reduced to 0.2 μm or less within 4 minutes of the polishing time, the flatness is particularly good, and it is suggested that the amount of depression due to dishing or thinning is extremely small.

Example 1 A tetrabromobisphenol A type epoxy resin having an epoxy equivalent of 500 (YDB-500 manufactured by Toto Kasei Co., Ltd.)
Of cresol novolak type epoxy resin having an epoxy equivalent of 220 (YDCN-220 manufactured by Toto Kasei Co., Ltd.) as a solid content of 13 parts by weight, 2.8 parts by weight of dicyandiamide as a curing agent, and a curing accelerator 0.1 parts by weight of 2-ethyl-4-methylimidazole as a solvent, and 25% of N, N-dimethylformamide as a solvent
A varnish consisting of parts by weight is 0.2 mm thick as a paper base.
And dried by heating at 180 ° C. to obtain a prepreg having a resin content of 55% by weight after drying. 50c
Six prepregs cut into m-squares were stacked, sandwiched between metal plates, and pressed under the conditions of a temperature of 170 ° C., a pressure of 5 MPa, and a time of 2 minutes to produce a laminated plate having six layers and a thickness of 1.2 mm. This laminated board was cut into a circle having a diameter of 38 cm, and a groove having a width of 2 mm and a depth of 0.5 mm was formed on the surface at a pitch of 15 mm.
To form a polishing layer. Next, nitrile rubber having a thickness of 1 mm (bulk modulus = 1) was used as a cushion layer.
(40 MPa, tensile elasticity = 4.5 MPa) and the polishing layer were bonded together with a double-sided adhesive tape (No. 591) manufactured by Nitto Denko to produce a polishing pad.

Example 2 A wet foamed polyurethane (bulk modulus = 3 MPa, tensile modulus = 50 MPa) having a thickness of 1.2 mm obtained by impregnating a nonwoven fabric with a polyurethane solution as a cushion layer, and the same polishing layer as in Example 1 Was bonded with a double-sided adhesive tape 442J (double-sided adhesive tape based on a polyester film) of Sumitomo 3M Co., Ltd. to produce a polishing pad.

Example 3 76% by weight of a polymethyl methacrylate resin (Sumipex MH manufactured by Sumitomo Chemical Co., Ltd.) and 24% by weight of a crosslinked polyvinylpyrrolidone powder (Rubicross M manufactured by BASF) were melt-extruded and kneaded to obtain pellets. The pellets were molded into a resin plate having a thickness of 1.2 mm and a diameter of 38 cm with an injection press molding machine IP-1050 (Komatsu Ltd.). 2 mm wide and 0.5 m deep on the surface of this resin plate
The groove of m was formed in a grid shape with a pitch width of 15 mm to prepare a polishing layer. Next, the same cushion layer as in Example 2 was applied to Sumitomo 3
A polishing pad was prepared by laminating with a double-sided adhesive tape 442J (double-sided adhesive tape based on a polyester film) from M Corporation.

Example 4 In Example 3, the resin composition was 88% by weight of a polymethyl methacrylate resin, and the cross-linked polyvinyl pyrrolidone powder 1
A polishing pad was produced in the same manner except that the amount was 2% by weight.

Comparative Example 1 78 parts by weight of a polyether-based urethane polymer (Adiprene L-325 manufactured by Uniroyal Co.) and 4,4'-methylene-
Bis-2-chloroaniline 20 parts by weight and hollow polymer microspheres (Expancel 551 DE manufactured by Chemo Nobel)
1.8 parts by weight were mixed with a RIM molding machine and discharged into a mold to produce a polymer molded body. This polymer molded body was sliced to a thickness of 1.2 mm with a slicer to produce a sheet of hard foamed polyurethane, and the same groove processing as in Example 1 was performed to produce a polishing layer having a diameter of 38 cm. Next, a double-sided adhesive tape 442 manufactured by Sumitomo 3M Co., Ltd.
J (a double-sided adhesive tape using a polyester film as a base material) was bonded to prepare a polishing pad.

Comparative Example 2 51% by weight of a base material having an isocyanate group content of 23% (C4421 manufactured by Nippon Polyurethane Co., Ltd.) and an OH value of 320
(KOH mg / g) curing agent (Nippon Polyurethane Co., Ltd.)
N4276) was kneaded while defoaming, and then cured in a mold to produce a 1.2 mm thick polyurethane sheet. This sheet was subjected to the same groove processing as in Example 1 to produce a polishing layer having a diameter of 38 cm. Next, the same cushion layer as in Example 2 was bonded with a double-sided adhesive tape 442J (double-sided adhesive tape using a polyester film as a base material) of Sumitomo 3M Co., Ltd. to produce a polishing pad.

Comparative Example 3 A polishing pad was produced in the same manner as in Example 3 except that a resin plate was formed by injection press using only the polymethyl methacrylate resin.

Comparative Example 4 In Example 3, the resin composition was such that the polymethyl methacrylate resin was 94% by weight, and the crosslinked polyvinyl pyrrolidone powder 6 was used.
A polishing pad was prepared in the same manner except that the content was changed to wt%.

Comparative Example 5 A pellet of transparent ABS resin (manufactured by Toray Industries, Inc.) was molded into a resin plate having a thickness of 1.2 mm and a diameter of 38 cm using an injection press molding apparatus (Komatsu Ltd.). On the surface of this resin plate, grooves having a width of 2 mm and a depth of 0.5 mm were formed in a grid pattern with a pitch width of 15 mm to prepare a polishing layer. Next, the same cushion layer as in Example 2 was bonded with a double-sided adhesive tape 442J (double-sided adhesive tape using a polyester film as a base material) of Sumitomo 3M Co., Ltd. to produce a polishing pad. (Evaluation of physical properties and CMP polishing) For the polishing layers of Examples 1 to 4 and Comparative Examples 1 to 5, bending elastic modulus, durometer D hardness, center line average roughness Ra and ten point average roughness Rz after dressing, and water Was measured. Table 1 shows the results. Next, for the polishing pads of Examples 1 to 4 and Comparative Examples 1 to 5, CMP polishing evaluation of the solid oxide film was performed, and the polishing rate, the number of scratches, and the number of remaining dusts were measured. Table 1 shows the results. Furthermore, CMP polishing evaluation of the oxide film with the concavo-convex pattern was performed, and a global step with respect to the polishing time was measured. The results are shown in FIG.

From the results shown in Table 1 and FIG. 2, the flexural modulus is 2 GPa or more and / or the durometer D hardness is 8
By setting it to 0 or more, the global step can be eliminated quickly,
By having excellent flattening characteristics, and further reducing the contact angle with water of the polishing layer surface after dressing to 75 degrees or less, the number of scratches and the number of residual dusts are greatly reduced, and a high-quality substrate surface can be obtained. It turns out that it becomes possible.

[0058]

[Table 1]

[0059]

According to the polishing pad, the polishing apparatus and the polishing method of the present invention, the global step can be eliminated quickly by selectively polishing the projections of the unevenness on the surface of the semiconductor substrate. Also, it is possible to obtain a high-quality semiconductor substrate having a small amount of dents such as dishing and thinning, and having few scratches and residual dust.

[Brief description of the drawings]

FIG. 1 is a wiring pattern in a chip prepared on a 4-inch wafer used for polishing evaluation.

FIG. 2 is a graph showing a measurement result of a global step with respect to a polishing time in an example.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C058 AA09 CB01 CB02 CB03 CB10 DA12 DA17 5F043 AA24 AA26 AA31 DD16 EE40 FF07

Claims (9)

[Claims] 1. A polishing pad used for chemical mechanical polishing for flattening a substrate, wherein a contact angle with water is 75 ° or less, and the following (A) and / or (B) A polishing pad comprising a polishing layer satisfying requirements. (A) Flexural modulus is 2 GPa or more. (B) Surface hardness is 80 or more in durometer D hardness. 2. The semiconductor device according to claim 1, wherein the substrate is a semiconductor substrate having an interlayer insulating film formed on the substrate, wherein the interlayer insulating film is polished and removed to planarize the surface of the interlayer insulating film. The polishing pad according to claim 1, wherein 3. The semiconductor substrate according to claim 1, wherein said substrate is a semiconductor substrate in which a metal wiring whose main component is one of Cu, Al and W is embedded in a wiring groove formed on said substrate. 2. The polishing pad according to claim 1, wherein the polishing pad is removed by polishing to flatten the surface of the metal wiring. 4. A semiconductor substrate wherein an oxide film is buried in a groove formed on the substrate, wherein an unnecessary portion of the oxide film is polished and removed to flatten the surface of the oxide film. The polishing pad according to claim 1, wherein: 5. The polishing pad according to claim 1, wherein said polishing layer is made of a paper and / or cloth base laminate. 6. A polishing pad wherein the polishing layer according to claim 1 and a cushion layer having a bulk modulus of not less than 60 MPa and a tensile modulus of not less than 0.1 MPa and not more than 20 MPa are bonded to each other. The polishing pad according to claim 1, wherein: 7. The polishing pad according to claim 1, wherein a groove or a hole is formed on a surface of said polishing layer. 8. A polishing head, the polishing pad according to claim 1, which is arranged to face said polishing head, a polishing platen for fixing said polishing pad, and said polishing head and / or Alternatively, a polishing apparatus comprising a driving device for rotating the polishing platen. 9. A polishing head and / or a polishing head in a state where the substrate is fixed to a polishing head and the polishing pad according to claim 1 fixed to a polishing platen is pressed against said substrate. A polishing method characterized by rotating a board to polish a substrate.