JP5292958B2 - Polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing pad capable of uniformly polishing a polishing material up to 1.5 mm of the edge of a wafer in polishing the polishing material such as glass, a semiconductor, a dielectric/metal compound material, an integrated circuit, etc. while supplying slurry on the polishing pad. <P>SOLUTION: There are laminated: a polishing layer whose micro A-hardness is not lower than 80 degrees; a resin plate whose tensile strength is 10 to 70 MPa, whose thickness is 0.3 to 1.2 mm, whose impact strength is not lower than 100 J/m, and whose water absorption is not higher than 0.5%; and a cushion layer, in the order of the polishing layer, the resin plate, and the cushion layer. The polishing layer and the resin plate are integrated with an adhesive. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a polishing pad used to form a flat surface in semiconductors, dielectric / metal composites, integrated circuits, and the like.

  As the density of semiconductor devices increases, the importance of multilayer wiring and the accompanying interlayer insulation film formation, electrode formation of plugs, damascene, and the like is increasing. Along with this, the importance of the flattening process of these interlayer insulating films and electrode metal films has increased, and a polishing technique called CMP (Chemical Mechanical Polishing) has become widespread as an efficient technique for this flattening process. doing.

The polishing technology called CMP is a polishing pad that has a polishing layer as the material to be polished and supplies slurry, but it is necessary to increase the number of chips on the wafer due to the demand for improvement in productivity every year. For this reason, conventionally, an area from the edge up to 3 mm to the edge up to 1.5 mm has been required as a good polishing area of the wafer. However, the two-layer polishing pad composed of a polishing layer and a cushion layer as shown in Patent Document 1, which is conventionally known, cannot satisfy the requirements because the polishing characteristics of the wafer edge portion are unstable. . Further, although a polishing layer and stainless steel are known as a three-layer polishing pad comprising a polishing layer, a rigid layer, and an elastic element as shown in Patent Document 2, the followability of wafer waviness is poor and in-plane uniformity is known. However, there is no known polishing pad that can polish well to an edge of 1.5 mm.
Japanese National Patent Publication No. 5-505769 JP-A-6-77185

  In view of the background of the prior art, the present invention provides a method for polishing an edge 1. Of a wafer when polishing a material to be polished such as glass, semiconductor, dielectric / metal composite and integrated circuit while supplying a slurry onto a polishing pad. The object is to provide a polishing pad capable of uniformly polishing up to 5 mm.

In order to solve the above problems, the present invention employs the following means. That is, a polishing pad for polishing the surface of an insulating layer or metal wiring formed on a semiconductor wafer, a polishing layer having a micro A hardness of 80 degrees or more, and a tensile strength of 10 MPa or more and 70 MPa or less, A resin plate and a cushion layer having a thickness of 0.3 mm or more and 1.2 mm or less, an impact strength of 100 J / m or more, and a water absorption of 0.5% or less are a polishing layer, a resin plate, and a cushion layer. it is a sequentially stacked becomes, the said abrasive layer and said resin plate is a polishing pad which is characterized in that it is integrated with an adhesive.

  According to the present invention, when polishing a material to be polished such as glass, semiconductor, dielectric / metal composite and integrated circuit while supplying slurry onto a polishing pad, polishing capable of uniformly polishing the wafer edge to 1.5 mm. A pad can be provided.

  The present invention uniformly polishes the object to be polished such as glass, semiconductor, dielectric / metal composite and integrated circuit to the edge of the wafer of 1.5 mm when polishing while supplying the slurry onto the polishing pad. As a result of earnestly examining a polishing pad that can be used, a polishing layer having a micro rubber A hardness of 80 degrees or more, a tensile strength of 10 MPa to 70 MPa, a thickness of 0.3 mm to 1.2 mm, and impact strength Is a polishing pad in which a composite layer in which a resin plate with a water absorption of 0.5% or less is integrated with an adhesive is laminated in the order of a cushion layer, a polishing layer, a resin plate, and a cushion layer It has been clarified that such problems can be solved at once.

  As a polishing layer constituting the polishing pad of the present invention, a micro rubber A hardness of 80 degrees or more and a structure having closed cells forms a flat surface in a semiconductor, a dielectric / metal composite, an integrated circuit, or the like. Therefore, it is preferable. Although not particularly limited, materials for forming such a structure include polyethylene, polypropylene, polyester, polyurethane, polyurea, polyamide, polyvinyl chloride, polyacetal, polycarbonate, polymethyl methacrylate, polytetrafluoroethylene, epoxy resin, ABS resin, Examples include AS resin, phenol resin, melamine resin, neoprene rubber, butadiene rubber, styrene butadiene rubber, ethylene propylene rubber, silicon rubber, fluoro rubber, and resins mainly composed of these. Even in such a resin, a material mainly composed of polyurethane is more preferable in that the closed cell diameter can be controlled relatively easily.

  The polyurethane in the present invention is a polymer synthesized based on polyisocyanate polyaddition reaction or polymerization reaction. The compound used as the symmetry of the polyisocyanate is an active hydrogen-containing compound, that is, a compound containing two or more polyhydroxy groups or amino groups. Examples of the polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, but are not limited thereto. The polyhydroxy group-containing compound is typically a polyol, and examples thereof include polyether polyol, polytetramethylene ether glycol, epoxy resin-modified polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and silicone polyol. The combination and optimum amount of polyisocyanate and polyol, catalyst, foaming agent, and foam stabilizer are preferably determined according to the hardness, the bubble diameter, and the expansion ratio.

  As a method of forming closed cells in these polyurethanes, the chemical foaming method is generally used by blending various foaming agents into the resin during polyurethane production, but it is cured after foaming the resin by mechanical stirring. The method of making it can also be used preferably.

  The average cell diameter of such closed cells is preferably 30 μm or more and 150 μm or less, which is preferable in that both scratches are small and the flatness of local unevenness of the semiconductor substrate is good. The average cell diameter is more preferably 140 μm or less, and further preferably 130 μm or less. When the average bubble diameter is less than 30 μm, the number of scratches may increase, which may be undesirable. Further, when the average bubble diameter exceeds 150 μm, the flatness of local irregularities of the semiconductor substrate is deteriorated, which is not preferable. The average bubble diameter is a value measured by observing the cross section of the sample with a SEM at a magnification of 200, then measuring the bubble diameter of the recorded SEM photograph with an image processing apparatus, and taking the average value.

  A preferred embodiment of the present invention is a pad containing a polymer polymerized from polyurethane and a vinyl compound and having closed cells. Polyurethane becomes brittle when the hardness is increased, and it is difficult to obtain a uniform polishing pad having closed cells, although the toughness and hardness can be increased only with a polymer from a vinyl compound. By containing a polymer polymerized from polyurethane and a vinyl compound, it was possible to obtain a polishing pad containing closed cells and having high toughness and hardness.

  The vinyl compound in the present invention is a compound having a polymerizable carbon-carbon double bond. Specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl Methacrylate, 2-hydroxybutyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, acrylic acid, methacrylic acid, fumaric acid, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, maleic acid, maleic Dimethyl acid, diethyl maleate, dipropyl maleate, phenylmaleimide, Hexyl maleimide, isopropyl maleimide, acrylonitrile, acrylamide, vinyl chloride, vinylidene chloride, styrene, alpha-methyl styrene, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and the like. These monomers can be used alone or in combination of two or more.

Among the vinyl compounds described above, CH ₂ = CR ¹ COOR ² (R ¹ : methyl group, ethyl group, R ² : methyl group, ethyl group, propyl group, butyl group) is preferable. Among them, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate are easy to form closed cells in polyurethane, good in impregnation of monomers, easy to cure by polymerization, A foamed structure containing a polymer polymerized from a vinyl compound is preferable in that it has high hardness and good flattening characteristics.

  Examples of polymerization initiators for these vinyl compounds include azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), azobiscyclohexanecarbonitrile, benzoyl peroxide, lauroyl peroxide, isopropyl peroxydicarbonate, and the like. A radical initiator can be used. A redox polymerization initiator, for example, a combination of a peroxide and an amine can also be used. These polymerization initiators can be used not only alone but also by mixing two or more.

  As a method for impregnating a vinyl compound into polyurethane, a method in which polyurethane is immersed in a container containing a monomer and impregnated can be mentioned. In this case, it is also preferable to perform treatments such as heating, pressurization, decompression, stirring, shaking, and ultrasonic vibration for the purpose of increasing the impregnation rate.

  The amount of vinyl compound impregnated in polyurethane should be determined by the type of monomer and polyurethane used and the characteristics of the polishing pad to be produced. The content ratio of the polymer obtained from the vinyl compound in the polymerized and cured foam structure and polyurethane is preferably 30/70 to 80/20 by weight. When the content ratio of the polymer obtained from the vinyl compound is less than 30/70 by weight, the hardness of the polishing pad is lowered, which may not be preferable. On the other hand, if the content ratio exceeds 80/20, the elasticity of the polishing layer may be impaired, which may not be preferable.

  In addition, the polymer obtained from the vinyl compound in the polymerization-cured polyurethane and the polyurethane content can be measured by a pyrolysis gas chromatography / mass spectrometry method. As an apparatus that can be used in this method, a double shot pyrolyzer “PY-2010D” (manufactured by Frontier Laboratories) is used as a thermal decomposition apparatus, and “TRIO-1” (manufactured by VG) is used as a gas chromatograph / mass spectrometer. Can be mentioned.

  In the present invention, the polyurethane and the vinyl polymer are preferably not contained in a state where the polyurethane phase and the polymer phase polymerized from the vinyl compound are separated. Expressed quantitatively, the infrared spectrum of the polishing pad observed with a micro-infrared spectrometer having a spot size of 50 μm has an infrared absorption peak of polyurethane and an infrared absorption peak of a polymer polymerized from a vinyl compound. In other words, the infrared spectra at various points are almost the same. As a micro-infrared spectrometer used here, IRμs manufactured by SPECTRA-TECH can be mentioned.

  Various additives such as abrasives, antistatic agents, lubricants, stabilizers, and dyes may be added for the purpose of improving the characteristics of the manufactured polishing pad.

  The micro rubber A hardness of the polishing layer of the present invention refers to a value evaluated with a micro rubber hardness meter MD-1 manufactured by Kobunshi Keiki Co., Ltd. The micro-rubber A hardness meter MD-1 is capable of measuring the hardness of thin and small items that were difficult to measure with a conventional hardness meter, and is about 1/5 of a spring type rubber hardness meter (durometer) A type. Since it is designed and manufactured as a reduced model, a measured value that matches the hardness of the spring type hardness tester A type can be obtained. Since a normal polishing pad has a thickness of a polishing layer or a hard layer of less than 5 mm, it cannot be evaluated with a spring type rubber hardness tester A type, and therefore is evaluated with the micro rubber MD-1.

  The polishing layer of the present invention has a micro rubber A hardness of 80 degrees or more, preferably 90 degrees or more. When the micro rubber A hardness is less than 80 degrees, the flatness of local irregularities of the semiconductor substrate becomes poor, which may not be preferable.

  The density of the polishing layer of the present invention is a value measured using a Harvard pycnometer (JIS R-3503 standard) and water as a medium.

The polishing layer of the present invention preferably has a density in the range of 0.3 to 1.1 g / cm ³ . When the density is less than 0.3 g / cm ³ , local flatness may be poor, and the global level difference may be increased. When the density exceeds 1.1 g / cm ³ , scratches are likely to occur. A more preferable density is 0.6 to 0.9 g / cm ³ , and a more preferable density is 0.65 to 0.85 g / cm ³ .

  On the surface of the polishing layer of the polishing pad of the present invention, in order to suppress the hydroplane phenomenon, grooves (grooves) that can be taken by a normal polishing pad, such as a grooving shape, dimple shape, spiral shape, concentric shape, etc., are formed and used. Is done.

  The resin plate bonded and integrated with the polishing layer of the present invention needs to have a tensile strength of 10 Mpa or more and 70 MPa or less. When the tensile strength is less than 10 MPa, the laminated polishing pad cannot be uniformly polished to an edge of 1.5 mm because the polishing rate is unstable at the edge portion when polishing is performed. When the tensile strength exceeds 70 MPa, the in-plane uniformity of the polishing characteristics is poor, which is not preferable. The tensile strength of the present invention is a stress at the time of breaking by applying a tensile stress to a dumbbell shape. An example of a measuring device is Tensilon Universal Testing Machine RTM-100 manufactured by Orientec. As measurement conditions, the test speed is 5 cm / min, the test piece shape is a dumbbell shape having a width of 5 mm and a sample length of 50 mm.

  The thickness of the resin plate of this invention needs to be 0.3 mm or more and 1.2 mm or less. When the thickness of the resin plate is less than 0.3 mm, polishing is not preferable because the edge portion has an unstable polishing rate and cannot be uniformly polished to an edge of 1.5 mm. When the thickness of the resin plate exceeds 1.2 mm, the in-plane uniformity of the polishing characteristics is poor, which is not preferable.

  The impact strength of the resin plate of the present invention needs to be 100 J / m or more. When the impact strength is less than 100 J / m, the resin plate causes fatigue failure while polishing a large amount of the wafer, which is not preferable. The impact strength was evaluated according to the Izod method indicated in JIS K 6911-1962.

  The water absorption of the resin plate of the present invention needs to be 0.5% or less. When the water absorption rate of the resin plate exceeds 0.5%, swelling occurs during polishing, the composite layer in which the polishing layer and the resin plate are integrated is deformed, and the polishing characteristics are improved while polishing a large amount of wafers. Since it worsens, it is not preferable. The water absorption rate is determined by first drying the resin plate in vacuum, measuring the weight, immersing it in water for 24 hours, and then measuring the weight after thoroughly removing the surface adhering water. The value obtained by dividing the difference in weight afterwards by the weight before immersion was defined as the water absorption rate.

  Specific examples of the material of the resin plate of the present invention include acrylonitrile butadiene styrene resin, chlorinated polyethylene acrylonitrile styrene resin, acrylonitrile ethylene styrene resin, acrylonitrile butadiene styrene / vinyl chloride blend resin, ethylene / vinyl acetate / vinyl chloride copolymer. Polycarbonate resin, polycarbonate / acrylonitrile butadiene styrene blend resin, polyphenylene ether resin, rigid polyurethane resin, acrylic modified polyvinyl chloride resin, and the like, but are not limited thereto.

  The polishing layer and the resin plate of the present invention must be integrated with an adhesive. Here, it excludes when using adhesives, such as a double-sided tape. Examples of the adhesive include acrylic resin-based adhesives, α-olefin-based adhesives, urethane resin-based adhesives, and hot-melt adhesives, which are preferable in that hot-melt adhesives can be bonded in a short time. As hot-melt adhesives, Hibon (registered trademark) series manufactured by Hitachi Chemical Polymer Co., Ltd., Takemelt (registered trademark) MA series of Mitsui Takeda Chemical Co., Ltd., Aronmelt (registered trademark) R series of Toa Gosei Co., Ltd., Examples include Nittaite (registered trademark) ARX series of Nitta Gelatin Co., Ltd. and Bond (registered trademark) KUM series of Konishi Co., Ltd.

  The thickness of the hot melt adhesive is preferably 30 to 150 μm because the adhesive strength can be maintained high.

  It is preferable to laminate a cushion layer having a bulk elastic modulus of 40 MPa or more and a tensile elastic modulus of 1 MPa or more and 20 MPa or less on the polishing layer of the present invention because the in-plane uniformity is good. The volume modulus is a volume change measured by applying an isotropic applied pressure to an object whose volume has been measured in advance. Volume modulus = applied pressure / (volume change / original volume).

  The volume modulus of elasticity of the present invention was measured as follows. A sample piece and 23 ° C. water were placed in a stainless steel measuring cell having an internal volume of about 40 mL, and a borosilicate glass pipette (minimum scale 0.005 mL) having a capacity of 0.5 mL was attached. Separately, a tube made of polyvinyl chloride resin (inner diameter 90 mmφ × 2000 mm, wall thickness 5 mm) is used as a pressure vessel, and the measurement cell in which the above sample piece is placed is placed therein. V1 was measured. Subsequently, the sample was not put in the measurement cell, and nitrogen was pressurized at the pressure P shown in Table 1, and the volume change V0 was measured. A value obtained by dividing the pressure P by ΔV / Vi = (V1−V0) / Vi was calculated as the volume modulus of the sample.

  The bulk modulus of the present invention is the bulk modulus when a pressure of 0.04 to 0.14 MPa is applied to the sample at 23 ° C.

  The volume elastic modulus of the cushion layer of the present invention is preferably 40 MPa or more. If it is less than 40 MPa, the in-plane uniformity of the entire surface of the semiconductor substrate may be impaired, which may be undesirable. Another reason is that slurry and water flowing into the holes penetrating the front and back surfaces of the polishing pad are formed in the cushion layer. Impregnation may change the cushion characteristics over time, which may be undesirable. A more preferable range of the bulk modulus is 200 MPa or more.

  The tensile modulus of the present invention is determined by applying a tensile stress to a dumbbell shape and measuring the tensile stress in a range of tensile strain (= change in tensile length / original length) from 0.01 to 0.03. Elastic modulus = ((tensile stress when tensile strain is 0.03) − (tensile stress when tensile strain is 0.01)) / 0.02. An example of a measuring device is Tensilon Universal Testing Machine RTM-100 manufactured by Orientec. As measurement conditions, the test speed is 5 cm / min, the test piece shape is a dumbbell shape having a width of 5 mm and a sample length of 50 mm.

  The tensile elastic modulus of the cushion layer of the present invention is preferably 1 MPa or more and 20 MPa or less. If the tensile elastic modulus is less than 1 MPa, the in-plane uniformity over the entire surface of the semiconductor substrate is impaired, which may not be preferable. Even when the tensile elastic modulus exceeds 20 MPa, the in-plane uniformity of the entire surface of the semiconductor substrate is impaired, which may not be preferable. A more preferable tensile elastic modulus range is 1.2 MPa or more and 10 MPa or less.

  As such a cushion layer, non-foamed elastomers such as natural rubber, nitrile rubber, neoprene (registered trademark) rubber, polybutadiene rubber, thermosetting polyurethane rubber, thermoplastic polyurethane rubber, and silicone rubber can be raised. It is not limited to. The thickness of the cushion layer is preferably in the range of 0.3 to 2 mm. If it is less than 0.5 mm, in-plane uniformity over the entire surface of the semiconductor substrate is impaired, which may not be preferable. If it exceeds 2 mm, local flatness is impaired, which may not be preferable. A more preferable thickness range is 0.5 mm or more and 2 mm or less. A more preferable range is 0.75 mm or more and 1.75 mm or less.

  Using the polishing pad of the present invention, the unevenness of the insulating film and the unevenness of the metal wiring on the semiconductor wafer are locally planarized using silica-based slurry, aluminum oxide-based slurry, cerium oxide-based slurry, etc. as the slurry. Can be reduced, global steps can be reduced, and dishing can be suppressed. As specific examples of the slurry, CAB-O-SPERSE (registered trademark) SC-1 for CMP, CAB-O-SPERSE (registered trademark) SC-112 for CMP, SEMI-SPERSE (registered trademark) AM100 for CMP manufactured by Cabot Corporation. , SEMI-SPERSE (registered trademark) AM100C for CMP, SEMI-SPERSE (registered trademark) 12 for CMP, SEMI-SPERSE (registered trademark) 25 for CMP, SEMI-SPERSE (registered trademark) W2000 for CMP, SEMI-SPERSE for CMP (Registered trademark) W-A400 and the like can be mentioned, but are not limited thereto.

The object of the polishing pad of the present invention is, for example, the surface of an insulating layer or metal wiring formed on a semiconductor wafer. As the insulating layer, an interlayer insulating film of metal wiring, a lower insulating film of metal wiring or element isolation The metal wiring is aluminum, tungsten, copper or the like, and there are structurally damascene, dual damascene, plug, and the like. When copper is used as the metal wiring, a barrier metal such as silicon nitride is also subject to polishing. As the insulating film, silicon oxide is mainly used at present, but a low dielectric constant insulating film is used due to the problem of delay time. With the polishing pad of the present invention, it is possible to satisfactorily measure the polishing state while polishing in a state where scratches are difficult to enter .

  The polishing pad of the present invention is suitably used for forming a flat surface on glass, semiconductors, dielectric / metal composites, integrated circuits and the like.

  Hereinafter, the details of the present invention will be described with reference to examples. However, the present invention is not construed as being limited by this embodiment. The measurement was performed as follows.

Micro rubber A hardness:
It is measured with a micro rubber hardness meter “MD-1” manufactured by Kobunshi Keiki Co., Ltd. The configuration of the micro rubber hardness tester “MD-1” is as follows.
1.1 Sensor part (1) Load method: cantilever leaf spring (2) Spring load: 0 point / 2.24 gf. 100 points / 33.85 gf
(3) Spring load error: ± 0.32 gf
(4) Needle size: Diameter: 0.16 mm cylindrical shape. 0.5mm height
(5) Displacement detection method: Strain gauge type (6) Pressure leg size: Outer diameter 4 mm Inner diameter 1.5 mm
1.2 Sensor driving unit (1) Driving method: Vertical driving by a stepping motor. Descent speed control by air damper (2) Vertical movement stroke: 12mm
(3) Descent speed: 10-30mm / sec
(4) Height adjustment range: 0 to 67 mm (distance between sample table and sensor pressing surface)
1.3 Sample stage (1) Sample stage size: Diameter 80mm
(2) Fine movement mechanism: Fine movement by an XY table and a micrometer head. Stroke: 15mm for both X and Y axes
(3) Level adjuster: Level adjustment body legs and round level.

  Bubble diameter measurement: By using a SEM2400 scanning electron microscope manufactured by Hitachi, Ltd. and analyzing the photograph observed at a magnification of 200 times with an image analyzer, all the bubble diameters present in the photograph are measured. The average value was defined as the average cell diameter.

  Measurement of bulk modulus: NBR rubber sheet 27 g (specific gravity 1.29, initial volume 21 ml) and 23 ° C. water were placed in a stainless steel measuring cell having an internal volume of about 40 mL, and 0.5 mL of borosilicate was added thereto. A glass pipette (minimum scale 0.005 mL) was attached. Separately, a tube made of polyvinyl chloride resin (inner diameter 90 mmφ × 2000 mm, wall thickness 5 mm) was used as a pressure vessel, and the measurement cell containing the above sample piece was put therein, and nitrogen was applied at the pressure P shown in Table 1. The volume was changed and the volume change V1 was measured. Subsequently, without putting the sample into the measurement cell, nitrogen was pressurized at the pressure P shown in Table 1, and the volume change V0 of only water was measured. A value obtained by dividing the pressure P by ΔV / Vi = (V1−V0) / Vi was calculated as the volume modulus of the sample.

Example 1
30 parts by weight of polypropylene glycol, 40 parts by weight of diphenylmethane diisocyanate, 0.5 parts by weight of water, 0.3 parts by weight of triethylamine, 1.7 parts by weight of a silicone foam stabilizer and 0.09 parts by weight of tin octylate are mixed in a RIM molding machine. The foamed polyurethane sheet having a thickness of 2.6 mm (micro rubber A hardness: 42, density: 0.76 g / cm ³ , average cell diameter of closed cells: 34 μm).

  The foamed polyurethane sheet was immersed in methyl methacrylate to which 0.2 part by weight of azobisisobutyronitrile was added for 60 minutes. Next, 15 parts by weight of polyvinyl alcohol “CP” (degree of polymerization: about 500, manufactured by Nacalai Tesque), 35 parts by weight of ethyl alcohol (special grade reagent, manufactured by Katayama Chemical), water 50 The foamed polyurethane sheet surface layer was coated with polyvinyl alcohol by being immersed in a solution consisting of parts by weight and then dried.

  Next, the foamed polyurethane sheet was sandwiched between two glass plates via a vinyl chloride gasket and polymerized and cured by heating at 65 ° C. for 6 hours and at 120 ° C. for 3 hours. After releasing from between the glass plates and washing with water, vacuum drying was performed at 50 ° C. A polishing layer was prepared by slicing the hard foam sheet thus obtained to a thickness of 2.00 mm.

The methyl methacrylate content in the polishing layer was 66% by weight. The micro rubber A hardness of the polishing layer was 98 degrees, the density was 0.81 g / cm ³ , and the average cell diameter of closed cells was 45 μm. A resin plate having a thickness of 1 mm was made of ABS resin manufactured by Toray Industries, Inc. The tensile strength of the resin plate was 30 MPa, the impact strength was 363 J / m, and the water absorption was 0.3%. As a hot melt adhesive, Hibon YR713-1W manufactured by Hitachi Chemical Polymer Co., Ltd. was applied to the resin plate at 120 μm and pressed with a polishing layer and a nip roll press to form a composite layer.
As a cushion layer, a 1.0 mm product (volume elastic modulus = 65 MPa, tensile elastic modulus = 4 MPa) of 65 ° in thermoplastic polyurethane micro rubber A hardness made by Nippon Matai Co., Ltd., Sekisui Chemical Co., Ltd. ) A laminate was prepared through a 5582W adhesive layer (intermediate tape), and Sekisui Chemical Co., Ltd. double-sided tape 5604 TDX was bonded to the back as a back tape.

  This laminated body is punched into a circle having a diameter of 775 mm, and a lattice-shaped XY-groove having a groove width of 1 mm, a groove depth of 0.825 mm, and a groove pitch of 20 mm is formed on the surface of the polishing layer with an NC router. did.

  It was affixed on the surface plate of a polishing machine ("Reflexion (registered trademark)" manufactured by Applied Materials). Retainering pressure = 10.4 psi, Z1 = 8.4 psi, Z2 = 4.2 psi, Z3 = 4.0 psi, platen rotation speed = 49 rpm, polishing head rotation speed = 51 rpm, slurry (Cabot Corporation) SS-12) was supplied at a flow rate of 150 cc / min, the polishing rate of the oxide film was 2300 angstroms / min under the polishing conditions of a load of 8 lbf with a Kinik dresser, a dressing time of 30 seconds and a polishing time of 1 minute. In-plane uniformity was very good at 12% with 1.5 mm edge exclusion. As a result of continuous testing of the wafer under these conditions, about 1500 wafers could be polished and the polishing characteristics could be maintained.

  When scratches of 0.18 μm or more were measured on the polished wafer using a defect inspection apparatus trade name “SP-1” manufactured by KLA-Tencol, the number of scratches was as good as 4 to 15 solids.

Example 2
30 parts by weight of polypropylene glycol, 40 parts by weight of diphenylmethane diisocyanate, 0.5 parts by weight of water, 0.3 parts by weight of triethylamine, 1.7 parts by weight of a silicone foam stabilizer and 0.09 parts by weight of tin octylate are mixed in a RIM molding machine. The foamed polyurethane sheet having a thickness of 2.6 mm (micro rubber A hardness: 42, density: 0.76 g / cm ³ , average cell diameter of closed cells: 34 μm).

  The foamed polyurethane sheet was immersed in methyl methacrylate to which 0.2 part by weight of azobisisobutyronitrile was added for 60 minutes. Next, 15 parts by weight of polyvinyl alcohol “CP” (degree of polymerization: about 500, manufactured by Nacalai Tesque), 35 parts by weight of ethyl alcohol (special grade reagent, manufactured by Katayama Chemical), water 50 The foamed polyurethane sheet surface layer was coated with polyvinyl alcohol by being immersed in a solution consisting of parts by weight and then dried.

  Next, the foamed polyurethane sheet was sandwiched between two glass plates via a vinyl chloride gasket and polymerized and cured by heating at 65 ° C. for 6 hours and at 120 ° C. for 3 hours. After releasing from between the glass plates and washing with water, vacuum drying was performed at 50 ° C. The hard foamed sheet thus obtained was sliced to a thickness of 1.50 mm to produce a polishing layer.

The methyl methacrylate content in the polishing layer was 66% by weight. The micro rubber A hardness of the polishing layer was 98 degrees, the density was 0.82 g / cm ³ , and the average cell diameter of closed cells was 40 μm. A resin plate having a thickness of 0.5 mm was made of AES resin manufactured by Sumitomo ABS Latex Co., Ltd. The tensile strength of the resin plate was 44 MPa, the impact strength was 540 J / m, and the water absorption rate was 0.3%. As a hot melt adhesive, MA-3002T manufactured by Mitsui Takeda Chemical Co., Ltd. was applied to the resin plate at 75 μm, and pressed with a polishing layer and a nip roll press to form a composite layer.
As a cushion layer, a 1.0 mm product (volume elastic modulus = 65 MPa, tensile elastic modulus = 4 MPa) of 65 ° in thermoplastic polyurethane micro rubber A hardness made by Nippon Matai Co., Ltd., Sekisui Chemical Co., Ltd. ) A laminate was prepared through a 5582W adhesive layer (intermediate tape), and Sekisui Chemical Co., Ltd. double-sided tape 5604 TDX was bonded to the back as a back tape.

  This laminated body is punched into a circle having a diameter of 775 mm, and a lattice-shaped XY-groove having a groove width of 1 mm, a groove depth of 0.60 mm, and a groove pitch of 20 mm is formed on the surface of the polishing layer with an NC router. did.

  It was affixed on the surface plate of a polishing machine ("Reflexion (registered trademark)" manufactured by Applied Materials). Retainering pressure = 11.4 psi, Z1 = 8.0 psi, Z2 = 4.2 psi, Z3 = 4.0 psi, platen rotation speed = 49 rpm, polishing head rotation speed = 51 rpm, slurry (Cabot Corporation) SS-12) was flown at a flow rate of 150 cc / min, the polishing rate of the oxide film was 2200 angstroms / min under the polishing conditions of a load of 8 lbf with a SEASOL dresser, a dressing time of 30 seconds and a polishing time of 1 minute. In-plane uniformity was very good at 11% with 1.5 mm edge exclusion. As a result of continuous testing of the wafer under these conditions, about 1800 wafers could be polished and the polishing characteristics could be maintained.

  When scratches of 0.18 μm or more were measured on the polished wafer using a defect inspection apparatus trade name “SP-1” manufactured by KLA-Tencol, the number of scratches was as good as 4 to 10 solids.

Comparative Example 1
A polishing layer having a thickness of 2.00 mm similar to that of Example 1 was prepared.

The methyl methacrylate content in the polishing layer was 66% by weight. The micro rubber A hardness of the polishing layer was 98 degrees, the density was 0.81 g / cm ³ , and the average cell diameter of closed cells was 45 μm.
As a cushion layer, a 1.0 mm product (volume elastic modulus = 65 MPa, tensile elastic modulus = 4 MPa) of 65 ° in thermoplastic polyurethane micro rubber A hardness made by Nippon Matai Co., Ltd., and the polishing layer and Sekisui Chemical Co., Ltd. ) A laminate was prepared through a 5582W adhesive layer (intermediate tape), and Sekisui Chemical Co., Ltd. double-sided tape 5604 TDX was bonded to the back as a back tape.

  This laminated body is punched into a circle having a diameter of 775 mm, and a lattice-shaped XY-groove having a groove width of 1 mm, a groove depth of 0.825 mm, and a groove pitch of 20 mm is formed on the surface of the polishing layer with an NC router. did.

  It was affixed on the surface plate of a polishing machine ("Reflexion (registered trademark)" manufactured by Applied Materials). Retainering pressure = 10.4 psi, Z1 = 8.4 psi, Z2 = 4.2 psi, Z3 = 4.0 psi, platen rotation speed = 49 rpm, polishing head rotation speed = 51 rpm, slurry (Cabot Corporation) SS-12) was supplied at a flow rate of 150 cc / min, the polishing rate of the oxide film was 2300 angstroms / min under the polishing conditions of a load of 8 lbf with a Kinik dresser, a dressing time of 30 seconds and a polishing time of 1 minute. In-plane uniformity was very poor at 40% with 1.5 mm edge exclusion.

  When scratches of 0.18 μm or more were measured on the polished wafer using a defect inspection apparatus trade name “SP-1” manufactured by KLA-Tencol, the number of scratches was as good as 4 to 15 solids.

Claims (2)

A polishing pad for polishing the surface of an insulating layer or metal wiring formed on a semiconductor wafer, wherein the polishing layer has a micro rubber A hardness of 80 degrees or more, a tensile strength of 10 MPa to 70 MPa, and A resin plate and a cushion layer having a thickness of 0.3 mm or more and 1.2 mm or less, an impact strength of 100 J / m or more, and a water absorption of 0.5% or less are formed of a polishing layer, a resin plate, and a cushion layer. A polishing pad, which is laminated in order, wherein the polishing layer and the resin plate are integrated with an adhesive. A method for manufacturing a semiconductor device, comprising a process of polishing a surface of an insulating layer or metal wiring formed on a semiconductor wafer using the polishing pad according to claim 1.