JP2018107301A - Polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent polishing pad which can achieve both flatness in planarizing concavity/convexity and wafer in-plane uniformity of a semiconductor wafer when used in a step of mechanically planarizing a surface of an insulator layer or a metal wiring formed on a substrate of semiconductor such as silicon.SOLUTION: A polishing pad has a structure in which an adhesive layer having a thickness of 70 μm or more and 150 μm or less and made of a material of 5.0 MPa or more and 17.0 MPa or less in elastic modulus is interposed between a polishing layer and a cushion base material layer. The polishing layer includes a foamed polyurethane sheet having closed cells and micro rubber A hardness of 70 degrees or more. The cushion base material layer includes polyurethane-based elastomer of 20 mass% or more and 30 mass% or less composed of a nonwoven fabric of ultrafine fiber bundles of 3.0 μm or more and 8.0 μm or less in average single fiber diameter.SELECTED DRAWING: None

Description

  The present invention relates to a polishing pad, and further relates to a polishing pad used in a step of mechanically flattening the surface of an insulating layer such as silicon formed on a semiconductor substrate or the surface of a metal wiring.

  Large scale integrated circuits (LSIs) typified by semiconductor memories have been integrated year by year, and accordingly, the manufacturing technology of large scale integrated circuits has also been increased in density. Furthermore, with this increase in density, the number of stacked semiconductor device manufacturing locations has also increased. Due to the increase in the number of stacked layers, unevenness of the main surface of the semiconductor wafer caused by stacking that has not been a problem in the past has become a problem. As a result, for example, as described in Non-Patent Document 1, in order to compensate for the insufficient depth of focus at the time of exposure due to unevenness caused by stacking, or to improve the wiring density by flattening the through hole portion Further, planarization of a semiconductor wafer using a chemical mechanical polishing technique has been studied. In general, a chemical mechanical polishing apparatus includes a polishing head that holds a semiconductor wafer that is an object to be processed, a polishing pad that performs polishing of the object to be processed, and a polishing surface plate that holds the polishing pad. Then, the polishing process of the semiconductor wafer uses a slurry made of an abrasive and a chemical solution to move the semiconductor wafer and the polishing pad relative to each other, thereby removing the protruding portion of the layer on the surface of the semiconductor wafer and smoothing the layer on the wafer surface. It is to make. It is approximately proportional to the relative speed and load between the semiconductor wafer and the polishing pad. Therefore, in order to polish each part of the semiconductor wafer uniformly, 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 is deteriorated. For this reason, a polyurethane foam sheet having a Shore A hardness of 80 degrees or more is mainly used. In addition, since it is necessary to make the load applied to the semiconductor wafer uniform, an elastic material having a strain constant of 6 microns / psi or more is used when the cushion layer under the polishing layer receives a predetermined pressure exceeding 4 psi. (See Patent Document 1), or having a hydraulic module greater than 250 psi for a compression force of approximately 1 psi when a compression force selected in the range of 4 psi to 20 psi is applied (see Patent Document 2). It has been introduced. As a cushion layer satisfying these physical properties, a cellular hollow body (whether communicated or independent), Dotex's Politex, Suba, etc. are introduced. However, in the laminated polishing pad mainly composed of a foamed polyurethane pad having a Shore A hardness of 80 degrees or more and these cushion layers, the in-wafer plane representing the flatness of the unevenness and the uniformity of the load applied to the semiconductor wafer are required. There was a problem that it was impossible to achieve both uniformity.

Japanese National Patent Publication No. 5-505769 JP-A-6-21028

Nikkei Microdevice, 1994, July, 50-57

  Accordingly, an object of the present invention relates to a polishing pad in view of the background of the above prior art, and further mechanically planarizes the surface of an insulating layer formed on a semiconductor substrate such as silicon or the surface of a metal wiring. An object of the present invention is to provide a suitable polishing pad capable of achieving both flatness for flattening irregularities and uniformity within a wafer surface of a semiconductor wafer.

  The present invention is to solve the above problems, and the polishing pad of the present invention includes a polishing layer containing a foamed polyurethane sheet having a micro rubber A hardness of 70 degrees or more, and a polyurethane of 20% by mass to 30% by mass. It is made of a material having an elastic modulus of 5.0 MPa or more and 17.0 MPa or less with a cushion base material layer made of a nonwoven fabric of ultrafine fiber bundles containing a base elastomer and having an average single fiber diameter of 3.0 μm or more and 8.0 μm or less. A polishing pad having a structure in which an adhesive layer having a thickness of 70 μm or more and 150 μm or less is interposed.

  According to a preferred embodiment of the polishing pad of the present invention, the polyurethane rubber sheet has a micro rubber A hardness of 80 degrees or more.

  According to a preferred aspect of the polishing pad of the present invention, the adhesive layer is made of a material having an elastic modulus of 7.0 MPa to 15.0 MPa, and the thickness of the adhesive layer is 90 μm to 130 μm.

  According to a preferred embodiment of the polishing pad of the present invention, the compressibility of the nonwoven fabric is 2% or more and 8% or less.

  According to the preferable aspect of the polishing pad of this invention, the thickness of the said nonwoven fabric is 0.5 mm or more and 1.2 mm or less.

  According to the present invention, in the polishing pad used in the step of mechanically flattening the surface of the insulating layer formed on the semiconductor substrate such as silicon or the surface of the metal wiring, the flatness and the semiconductor wafer for flattening the unevenness Thus, a suitable polishing pad capable of achieving both in-plane uniformity of the wafer can be obtained.

  The polishing pad of the present invention is a non-woven fabric comprising a polishing layer containing a foamed polyurethane sheet having closed cells with micro rubber A hardness of 70 degrees or more, and an ultrafine fiber bundle having an average single fiber diameter of 3.0 μm or more and 8.0 μm or less. An adhesive layer (thickness 70 μm or more and 150 μm or less) made of a material having an elastic modulus of 5.0 MPa or more and 17.0 MPa or less between the cushion base material layer containing 20% by mass or more and 30% by mass or less polyurethane-based elastomer. A polishing pad characterized by having a structure with intervening metal.

  First, the micro rubber A hardness referred to in this specification will be described. This hardness refers to a value evaluated with a micro rubber hardness meter MD-1 manufactured by Kobunshi Keiki Co., Ltd. The micro rubber hardness meter MD-1 realizes the hardness measurement of thin and small samples, which is difficult to measure with a conventional hardness meter, and is about 1/5 of a spring type rubber hardness meter (durometer) A type. Since the model is designed and manufactured as a reduced model, the measured value is consistent with the hardness of the spring type rubber hardness tester A type. The micro rubber hardness tester MD-1 has a cylindrical size with a push needle size of 0.16 mm and a height of 0.5 mm. The load method is a cantilever plate spring, and the spring load is 2.24 mN at 0 point and 33.85 mN at 100 point. The needle lowering speed is measured by controlling the range of 10 to 30 mm / sec with a stepping motor. Since the thickness of the polishing layer or hard layer of a normal polishing pad is less than 5 mm, the spring type rubber hardness tester A type is too thin to be evaluated, and therefore can be evaluated with the micro rubber hardness tester MD-1.

  The polishing pad of the present invention has a micro rubber A hardness of 70 degrees or more, preferably 80 degrees or more, and more preferably 85 degrees or more. When the micro rubber A hardness is less than 70 degrees, the flatness of local irregularities of the semiconductor substrate may be poor. The polishing layer includes a foamed polyurethane sheet having closed cells. The polyurethane resin of the foamed polyurethane sheet having closed cells comprises an isocyanate component, a polyol component (high molecular weight polyol, low molecular weight polyol), and a chain extender. As the isocyanate component, a known compound in the field of polyurethane can be used without particular limitation. As the isocyanate component, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, Aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate; ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, etc. Aliphatic diisocyanate; 1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate Isocyanate, alicyclic diisocyanates such as norbornane diisocyanate. These may be used alone or in combination of two or more.

  Examples of the high molecular weight polyol include those usually used in the technical field of polyurethane. Examples include polyether polyols typified by polytetramethylene ether glycol, polyethylene glycol, etc., polyester polyols typified by polybutylene adipate, polycaprolactone polyols, reactants of polyester glycols such as polycaprolactone and alkylene carbonate, etc. Polyester polycarbonate polyol obtained by reacting ethylene carbonate with polyhydric alcohol and then reacting the obtained reaction mixture with organic dicarboxylic acid, polycarbonate polyol obtained by transesterification of polyhydroxyl compound and aryl carbonate Etc. These may be used alone or in combination of two or more.

  In addition to the high molecular weight polyols described above as the polyol component, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2 -Hydroxyethoxy) benzene, trimethylolpropane, glycerin, 1,2,6-hexanetriol, pentaerythritol, tetramethylolcyclohexane, methylglucoside, sorbitol, mannitol, dulcitol, sucrose, 2,2,6,6-tetrakis (Hydroxymethyl) cyclohexanol, diethanolamine, N- methyldiethanolamine, and can be used in combination of low molecular weight polyols such as triethanolamine. Moreover, low molecular weight polyamines, such as ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine, can also be used in combination. Also, alcohol amines such as monoethanolamine, 2- (2-aminoethylamino) ethanol, and monopropanolamine can be used in combination. These low molecular weight polyols and low molecular weight polyamines may be used alone or in combination of two or more. The blending amount of the low molecular weight polyol, the low molecular weight polyamine or the like is not particularly limited and is appropriately determined depending on the properties required for the polishing layer to be produced.

  When a polyurethane resin foam is produced by a prepolymer method, a chain extender is used for curing the prepolymer. The chain extender is an organic compound having two or more active hydrogen groups, and examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH). Specifically, 4,4′-methylenebis (o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 4,4′-methylenebis (2,3-dichloroaniline), 3,5 -Bis (methylthio) -2,4-toluenediamine, 3,5-bis (methylthio) -2,6-toluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2 , 6-diamine, trimethylene glycol-di-p-aminobenzoate, polytetramethylene oxide-di-p-aminobenzoate, 4,4′-diamino-3,3 ′, 5,5′-tetraethyldiphenylmethane, 4, 4'-diamino-3,3'-diisopropyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3 ', 5,5'-tetra Sopropyldiphenylmethane, 1,2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane, N, N′-di-sec-butyl -4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, m-xylylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, m-phenylenediamine And polyamines exemplified by p-xylylenediamine and the like, or the low molecular weight polyols and low molecular weight polyamines mentioned above. These may be used alone or in combination of two or more.

  The content ratio of the isocyanate component, the polyol component, and the chain extender can be variously changed depending on the molecular weight of each, the desired physical properties of the polishing layer, and the like. In order to obtain a polishing layer having desired polishing characteristics, the number of isocyanate groups of the isocyanate component relative to the total number of active hydrogen groups (hydroxyl group + amino group) of the polyol component and the chain extender is 0.80 to 1.20. Is more preferable, and 0.99 to 1.15 is more preferable. When the number of isocyanate groups is outside the above range, curing failure occurs and the required specific gravity and hardness cannot be obtained, and the polishing characteristics tend to be deteriorated.

  The polyurethane resin foam can be produced by applying a known urethanization technique such as a melting method or a solution method, but is preferably produced by a melting method in consideration of cost, work environment, and the like.

  The polyurethane resin foam can be produced by either the prepolymer method or the one-shot method. However, an isocyanate-terminated prepolymer is synthesized beforehand from an isocyanate component and a polyol component, and this is reacted with a chain extender. The polymer method is preferred because the resulting polyurethane resin has excellent physical properties.

  Examples of the method for producing a polyurethane resin foam include a method of adding hollow beads, a mechanical foaming method, and a chemical foaming method.

  In particular, a mechanical foaming method using a silicone surfactant which is a copolymer of polyalkylsiloxane and polyether and does not have an active hydrogen group is preferable.

  In addition, you may add stabilizers, such as antioxidant, a lubricant, a pigment, a filler, an antistatic agent, and another additive as needed.

  Polyurethane resin foam can be manufactured by batch feeding each component into a container and stirring, or by continuously supplying each component and non-reactive gas to the stirring device and stirring, It may be a continuous production method in which a dispersion is sent out to produce a molded product.

  In addition, the prepolymer that is the raw material of the polyurethane resin foam is placed in a reaction vessel, and then a chain extender is added and stirred, and then poured into a casting mold of a predetermined size to produce a block, and the block is shaped like a bowl or a band saw. In the method of slicing using a slicer, or in the above-described casting step, a thin sheet may be used. Alternatively, a raw material resin may be dissolved and extruded from a T-die to directly obtain a sheet-like polyurethane resin foam.

  When the polyurethane resin foam has closed cells, the average cell diameter of the closed cells is preferably 30 to 100 μm, more preferably 30 to 80 μm. When deviating from this range, the polishing rate tends to decrease or the flatness of the polished wafer tends to decrease.

  The specific gravity of the polyurethane resin foam is preferably 0.5 to 1.0. When the specific gravity is less than 0.5, the surface strength of the polishing layer decreases, and the flatness of the material to be polished tends to decrease. On the other hand, when the ratio is larger than 1.0, the number of bubbles on the surface of the polishing layer is reduced and the flatness is good, but the polishing rate tends to decrease.

  The polishing surface in contact with the wafer of the polishing layer preferably has an uneven structure for holding and renewing the slurry. The polishing layer made of foam has many openings on the polishing surface and has the function of holding and updating the slurry. By forming a concavo-convex structure on the polishing surface, the slurry can be held and updated more efficiently. This can be carried out well, and the wafer can be prevented from being broken due to adsorption with the wafer. The concavo-convex structure is not particularly limited as long as it is a shape that holds and renews the slurry. For example, an XY lattice groove, a concentric circular groove, a through hole, a non-penetrating hole, a polygonal column, a cylinder, a spiral groove, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. In addition, these uneven structures are generally regular, but in order to make the slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible. The shape of the polishing layer is not particularly limited, and may be circular or long. The size of the polishing layer can be appropriately adjusted according to the polishing apparatus to be used. In the case of a circular shape, the diameter is about 30 to 150 cm, and in the case of a long shape, the length is about 5 to 15 m. The width is about 60 to 250 cm.

The thickness of the polishing layer is not particularly limited, but is usually preferably about 0.5 to 2.5 mm. Specific examples of the foamed polyurethane sheet include a sheet in which a polymer polymerized from polyurethane and a vinyl compound is integrated. The polyurethane 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, two or more polyhydroxy or amino group-containing compounds. Examples of the polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, but are not limited thereto. The polyhydroxy is typically a polyol, and examples of the polyol include polyether polyol, polypropylene glycol, polytetramethylene ether glycol, epoxy resin-modified polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and silicone polyol. Of these, polyurethane obtained by combining tolylene diisocyanate, diphenylmethane diisocyanate as the polyisocyanate, and polypropylene glycol and polytetramethylene ether glycol as the polyol is preferable because it has excellent moldability and is widely used. This vinyl compound is a compound having a vinyl group having a carbon-carbon double bond. Specifically, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methyl (α-ethyl) acrylate, ethyl (α-ethyl) acrylate, propyl (α-ethyl) acrylate, butyl (α-ethyl) ) Acrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl methacrylate, dimethylaminoethyl Methacrylate, diethylaminoethyl methacrylate, methacrylic acid, glycidyl methacrylate, ethylene glycol di Tacrylate, fumaric acid, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, maleic acid, dimethyl maleate, diethyl maleate, dipropyl maleate, acrylonitrile, acrylamide, vinyl chloride, styrene, α-methyl styrene, N-methyl maleimide N-ethylmaleimide, N-isopropylmaleimide, N-phenylmaleimide and the like. Among them, preferred vinyl compounds are methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methyl (α-ethyl) acrylate, ethyl (α-ethyl) acrylate, propyl (α-ethyl) acrylate, butyl. (Α-ethyl) acrylate. The polymer polymerized from the vinyl compound here is a polymer obtained by polymerizing the above vinyl compound, specifically, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, poly (n-butyl methacrylate). ), Polyisobutyl methacrylate, polymethyl (α-ethyl) acrylate, polyethyl (α-ethyl) acrylate, polypropyl (α-ethyl) acrylate, polybutyl (α-ethyl) acrylate, poly (2-ethylhexyl methacrylate), polyisodecyl Methacrylate, poly (n-lauryl methacrylate), poly (2-hydroxyethyl methacrylate), poly (2-hydroxypropyl methacrylate), poly (2-hydroxyethyl acrylate), poly (2-hydroxypropylene) Acrylate), poly (2-hydroxybutyl methacrylate), polydimethylaminoethyl methacrylate, polydiethylaminoethyl methacrylate, polymethacrylic acid, polyglycidyl methacrylate, polyethylene glycol dimethacrylate, polyfumaric acid, dimethyl polyfumarate, diethyl polyfumarate, dipropyl polyfumarate , Polymaleic acid, dimethylpolymaleate, diethylpolymaleate, dipropylmaleate, polyacrylonitrile, polyacrylamide, polyvinylchloride, polystyrene, poly (α-methylstyrene), poly (N-methylmaleimide), poly (N-ethylmaleimide) ), Poly (N-isopropylmaleimide), poly (N-phenylmaleimide) and the like. Among these, preferred polymers include polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, poly (n-butyl methacrylate), polyisobutyl methacrylate, polymethyl (α-ethyl) acrylate, polyethyl (α-ethyl) acrylate, polypropyl. (Α-Ethyl) acrylate and polybutyl (α-ethyl) acrylate can increase the hardness of the polishing layer and improve the planarization characteristics. Here, the content of the polymer polymerized from the vinyl compound is preferably 30% by weight or more and 50% by weight or less. When the content is less than 30% by weight, the hardness of the polishing layer may be lowered. If the content exceeds 50% by weight, the elasticity of the pad may be impaired. The content of the polymer polymerized from the polyurethane or vinyl compound in the polishing layer can be measured by a pyrolysis gas chromatography / mass spectrometry technique for the polishing pad. The apparatus that can be used in this method is a double shot pyrolyzer “PY-2010D” (manufactured by Frontier Laboratories) as a thermal decomposition apparatus, and “TRIO-1” (manufactured by VG) as a gas chromatograph / mass spectrometer. Can do. “Polymer polymerized from polyurethane and vinyl compound is integrated and contained” here means that the polyurethane phase and the polymer phase polymerized from vinyl compound are not contained in a separated state. However, when expressed quantitatively, the infrared spectrum obtained by observing various portions of the layer having essentially the polishing function in the pad with a micro infrared spectroscope having a spot size of 50 μm is the polyurethane. It has an infrared absorption peak and an infrared absorption peak of a polymer polymerized from a vinyl compound, which means that the infrared spectra at various locations are almost the same. As a micro infrared spectrometer used here, “IR μs” manufactured by SPECTRA-TECH can be mentioned. As a method for producing such a foamed polyurethane sheet, a vinyl compound is swollen in a soft foamed polyurethane sheet having a density in the range of 0.5 to 0.95 [g / cm ³ ], and then the vinyl is contained in the soft foamed polyurethane sheet. The method of polymerizing the compound is preferable because a foamed polyurethane sheet containing a polymer polymerized from polyurethane and a vinyl compound can be produced and flatness can be reduced by the obtained polishing layer.

  Among cushion base materials in which polyurethane nonwoven elastomers containing 20% by mass or more and 30% by mass or less are contained in a nonwoven fabric composed of an ultrafine fiber bundle having an average single fiber diameter of 3.0 μm or more and 8.0 μm or less, ultrafine fibers (bundles) Examples of the polymer that forms can include polyester, polyamide, polyolefin, polyphenylene sulfide (PPS), and the like. Many polycondensation polymers represented by polyester and polyamide have a high melting point and are excellent in heat resistance and are preferably used. Specific examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate, and potytrimethylene terephthalate. Specific examples of the polyamide include nylon 6, nylon 66, nylon 12, and the like.

  In addition, the polymer constituting the ultrafine fiber (bundle) may be copolymerized with other components, or may contain additives such as particles, flame retardant, and antistatic agent.

  It is important that the average single fiber diameter of the ultrafine fibers constituting the ultrafine fiber bundle is 3.0 μm or more and 8.0 μm or less. By setting the average single fiber diameter to 8.0 μm or less, it is possible to improve the in-plane uniformity of the wafer when polished with a polishing pad laminated with a polishing layer and an adhesive using the cushion base material layer. . The reason for this is that in a laminated polishing pad, the foamed polyurethane sheet is brought into contact as a polishing layer on the surface to be contacted with the wafer to be polished, but the fibers do not directly contact the polishing target, but for the polishing pad. It is presumed that when the fibers constituting the cushion base material have an average single fiber diameter of 8.0 μm or less, the stress applied to the wafer on the surface to be polished can be made uniform when used as a laminated polishing pad. On the other hand, by setting the average single fiber diameter to 3.0 μm or more, the number of processed wafers can be increased. A more preferable average single fiber diameter of the ultrafine fibers is 3.5 μm or more and 6.0 μm or less.

  The average single fiber diameter CV of the ultrafine fibers (bundle) is preferably in the range of 0.1 to 10%. The average single fiber diameter CV of the ultrafine fiber (bundle) here is a value obtained by dividing the standard deviation of the single fiber diameter of the ultrafine fiber by the average single fiber diameter in percentage [%]. The smaller the value, the more uniform the single fiber diameter.

  By setting the average single fiber diameter CV to 10% or less, the single fiber diameter of the ultrafine fibers becomes uniform and the raised surface is kept uniform, so that the surface of the adhesive force between the polishing layer and the cushion base material layer is maintained. It is preferable because internal plaque can be reduced. The average single fiber diameter CV is preferably as low as possible, but is substantially 0.1 or more.

  In order to obtain a desired average single fiber diameter CV, a known sea-island type composite die described in Japanese Patent Publication No. 44-18369 or the like is used. A technique such as a method of forming a molecular mutual array can be used. In this method, the number of distribution holes of the distribution plate is adjusted so that the molten polymer is uniformly dispersed, and the pressure on the back of the base is appropriate to make the fiber diameter of the ultrafine fibers in the composite single fiber uniform. A common method is to perform composite spinning using a sea-island-type pipe base with the base size adjusted.

  As a form of the ultrafine fiber bundle, the ultrafine fibers may be slightly separated from each other, may be partially bonded, or may be aggregated. Here, the bond refers to a chemical reaction or physical fusion, and the aggregation refers to a molecular force such as a hydrogen bond.

  In the fiber entanglement of the nonwoven fabric used for the cushion base material layer, fibers thicker than the ultrafine fibers defined above may be mixed. Here, the fiber diameter of the thick fibers is preferably 10 μm to 40 μm, but is not particularly limited. By mixing thick fibers, the strength of the polishing pad base material is reinforced, and characteristics such as cushioning properties can be improved. As a polymer which forms a fiber thicker than such an ultrafine fiber, the same polymer as that constituting the aforementioned ultrafine fiber can be employed. The blending amount of the fibers thicker than the ultrafine fibers with respect to the nonwoven fabric is preferably 30% by mass or less, more preferably 10% by mass or less, whereby the smoothness of the surface of the polishing pad substrate can be maintained. Moreover, it is preferable that the said thick fiber is not exposed to the surface from a viewpoint of polishing performance.

  As will be described later in the measurement method of the example, when fibers having a fiber diameter exceeding 8.0 μm are mixed, the fibers are excluded from the measurement target of the average fiber diameter as not corresponding to the ultrafine fibers. And

The nonwoven fabric which is a fiber entangled body used for the cushion base material layer is composed of short fibers obtained by forming a laminated fiber web using a card and a cross wrapper, and then performing needle punching or water jet punching. Nonwoven fabrics, nonwoven fabrics made of long fibers obtained from a spunbond method, a melt blow method, and the like, and nonwoven fabrics obtained by a papermaking method can be appropriately employed. Especially, the nonwoven fabric consisting of a short fiber and the spun bond nonwoven fabric can obtain the aspect of the ultrafine fiber bundle as described later by needle punching. Here, the thickness of the nonwoven fabric is preferably in the range of 1.0 mm to 4.0 mm. The density is preferably in the range of 0.15 g / cm ^{3 to} 0.60 g / cm ³ .

  The cushion base material layer used for the polishing pad needs to contain 20% by mass or more and 30% by mass or less of a polyurethane elastomer as the nonwoven fabric as the fiber entangled body. By containing the polyurethane-based elastomer, it is possible to prevent the ultrafine fibers from falling out of the cushion base material layer due to the binder effect, and to form uniform napping at the time of raising. Moreover, by containing a polyurethane-type elastomer, cushioning property is provided to a cushion base material layer, and the uniformity which was excellent in the thickness of the polishing pad using it is provided. Polyurethane elastomers such as polyurethane and polyurethane / polyurea elastomer can be used.

  As the polyol component of the polyurethane-based elastomer, polyester-based, polyether-based and polycarbonate-based diols, or copolymers thereof can be used. Moreover, aromatic diisocyanate, alicyclic isocyanate, aliphatic isocyanate, etc. can be used as a diisocyanate component.

  The weight average molecular weight of the polyurethane elastomer is preferably 50,000 to 300,000. By setting the weight average molecular weight to 50,000 or more, more preferably 100,000 or more, and further preferably 150,000 or more, the strength of the cushion base material layer can be maintained, and dropping of the ultrafine fibers can be prevented. Further, by setting the weight average molecular weight to 300,000 or less, more preferably 250,000 or less, it is possible to suppress the increase in the viscosity of the polyurethane solution and facilitate the impregnation of the ultrafine fiber layer.

  In the cushion base material layer, the polyurethane elastomer content is 20% by mass or more and 30% by mass or less. When the content is less than 20% by mass, the number of processed wafers is reduced. On the other hand, when the content exceeds 30% by mass, the in-plane uniformity of the wafer becomes poor. A more preferable range of the content of the polyurethane-based elastomer is 21% by mass or more and 28% by mass or less.

  As a solvent used when the polyurethane elastomer is applied to a nonwoven fabric which is a fiber entanglement, N, N′-dimethylformamide, dimethyl sulfoxide or the like can be preferably used. In addition, as the polyurethane-based elastomer, water-based polyurethane dispersed as an emulsion in water can also be used.

  The polyurethane elastomer is substantially added to the fiber entangled body by immersing the fiber entangled body (nonwoven fabric) in a polyurethane elastomer solution in which the polyurethane elastomer is dissolved in a solvent, and then dried. To solidify and solidify. In drying, the fiber entangled body and the polyurethane elastomer may be heated at a temperature that does not impair the performance.

  The raising treatment of the cushion base material layer thus obtained can be performed using sandpaper, roll sander or the like. In particular, by using sandpaper, uniform and dense napping can be formed.

  In addition, additives such as colorants, antioxidants, antistatic agents, dispersants, softeners, coagulation modifiers, flame retardants, antibacterial agents and deodorants are blended in polyurethane elastomers as necessary. Also good.

  After the polyurethane-based elastomer described above is applied to the nonwoven fabric, another elastomer may be applied to the cushion base material as a resin for preventing the fluff from falling. As other elastomers, the above-mentioned polyurethane, polyurea, polyurethane-polyurea elastomer, polyacrylic acid, acrylonitrile-butadiene elastomer, styrene-butadiene elastomer and the like are preferably used.

  By setting the adhesion amount of the polyurethane-based elastomer to 0.5% by mass or more and 6.0% by mass or less, it is possible to obtain a sufficient function for preventing fuzz removal. Moreover, the compression characteristic of a cushion base material layer can be maintained by making the adhesion amount of an elastomer into 6.0 mass% or less. A more preferable range of the adhesion amount of the elastomer is 1.0% by mass or more and 5.0% by mass or less.

The compression rate of the cushion base material is based on the initial thickness T0 [mm] when an initial load of 50 [g / cm ² ] is applied and the post-load thickness T1 [mm] when a load of 300 [g / cm ² ] is applied. It is a value calculated by (T0−T1) / T0 × 100 [%]. The compression ratio is preferably 2% or more and 8% or less. When the compression ratio is less than 2%, the cushion base material is hard and the flexibility is lowered, and thus the adhesive base material is peeled off. Moreover, there is a possibility that the uniformity in the wafer surface when using the polishing pad is poor. When the compression ratio exceeds 8%, the cushion base material is too soft and it is difficult to maintain a disk-like shape as a pad. Moreover, there is a possibility that the flattening characteristics when using the polishing pad are poor. More preferably, the compression rate is 3% or more and 7% or less.

The basis weight of the portion excluding the reinforcing layer described later of the cushion base material layer used for the polishing pad is preferably 100 g / m ² or more and 600 g / m ² or less. By making the basis weight 100 g / m ² or more, more preferably 150 g / m ² or more, the cushion base material layer has excellent shape stability and dimensional stability, and processing unevenness due to elongation of the cushion base material layer during polishing processing. Further, the occurrence of scratch defects can be suppressed. On the other hand, when the basis weight is 600 g / m ² or less, more preferably 300 g / m ² or less, handling of the polishing pad is facilitated, and the cushioning property of the polishing pad is moderately suppressed. The pressure can be reduced.

  Moreover, the thickness of the part except the reinforcement layer mentioned later of a cushion base material layer becomes like this. Preferably it is 0.1 mm or more and 10 mm or less. By making this thickness 0.1 mm or more, preferably 0.3 mm or more, the cushion base material layer has excellent shape stability and dimensional stability, processing unevenness due to thickness deformation of the cushion base material layer during polishing processing, Further, the occurrence of scratch defects can be suppressed. On the other hand, by setting the thickness of the cushion base material layer to 10 mm or less, more preferably 5 mm or less, the pressing pressure at the time of polishing can be sufficiently propagated.

  Moreover, it is also a preferable aspect that the cushion base material layer used for the polishing pad has a reinforcing layer on the other surface joined to the polishing layer having the foamed polyurethane sheet having closed cells through the adhesive. By providing the reinforcing layer, the polishing pad is excellent in form stability and dimensional stability, and processing unevenness and generation of scratch defects can be suppressed. The method for laminating is not particularly limited, but a thermocompression bonding method or a frame lamination method is preferably used. Any method of providing an adhesive layer between the reinforcing layer and the sheet-like material may be employed. Examples of the adhesive layer include polyurethane, styrene butadiene rubber (SBR), nitrile butadiene (NBR), polyamino acid and acrylic. A material having rubber elasticity such as an adhesive is preferably used. In consideration of cost and practicality, an adhesive such as NBR or SBR is preferably used. As a method for applying the adhesive, a method of applying it to a sheet in an emulsion or latex state is preferably used.

  As the reinforcing layer, a woven fabric, a knitted fabric, a nonwoven fabric (including paper), a film-like material (such as a plastic film or a metal thin film sheet), and the like can be employed.

  The cushion base material layer used for the polishing pad may have raised hair on the surface of the surface to be bonded to the polishing layer containing the foamed polyurethane sheet via an adhesive and raised.

  Next, a method for producing a cushion base material layer used for the polishing pad will be described.

  As a means for obtaining a fiber entanglement such as a nonwoven fabric formed by entanglement of ultrafine fiber bundles, it is preferable to use ultrafine fiber generating fibers. Although it is difficult to produce a fiber entanglement directly from an ultrafine fiber, for example, a fiber entanglement is produced from an ultrafine fiber generation type fiber composed of a sea component and an island component, and from the ultrafine fiber generation type fiber in this fiber entanglement By removing the sea component and generating ultrafine fibers composed of island components, a fiber entangled body (nonwoven fabric) formed by entanglement of the ultrafine fiber bundle can be obtained.

  The ultra-fine fiber generation type fiber is a sea-island type in which two component thermoplastic resins with different solvent solubility are used as sea components and island components, and the sea components are dissolved and removed using a solvent, etc., and the island components are used as ultra-fine fibers. It is possible to employ a peelable composite fiber that splits fibers into ultrafine fibers by alternately arranging fibers or two-component thermoplastic resin radially or in a multilayer shape on the fiber cross section, and separating and separating each component.

  For sea-island type fibers, sea-island type composite fibers that use a sea-island type composite base to spun two components of the sea component and the island component, and mixed spinning that mixes and spins the two components of the sea component and the island component are spun. Although there are fibers and the like, sea-island type composite fibers are preferably used from the viewpoint that ultrafine fibers having a uniform fineness are obtained, and that a sufficiently long ultrafine fiber is obtained and contributes to the strength of the sheet-like material.

  As the sea component of the sea-island fiber, polyethylene, polypropylene, polystyrene, copolymer polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, or the like, and polylactic acid can be used.

  The sea component may be dissolved and removed at any timing before applying the polyurethane elastomer that is an elastic polymer, after applying the polyurethane elastomer, or after raising treatment.

  As a method for obtaining a nonwoven fabric, as described above, a method in which a fiber web is entangled with a needle punch or a water jet punch, a spun bond method, a melt blow method, a paper making method, and the like can be employed. In forming an ultrafine fiber bundle, a method such as needle punching or water jet punching is preferably used.

  In the needle used for the needle punching process, the number of needle barbs (cuts) is preferably 1 to 9. By using one or more needle barbs, efficient fiber entanglement becomes possible. On the other hand, fiber damage can be suppressed by using 9 or less needle barbs.

  The total depth of the needle barb is preferably 0.04 to 0.09 mm. By setting the total depth to 0.04 mm or more, a sufficient catch on the fiber bundle can be obtained, so that efficient fiber entanglement is possible. On the other hand, fiber damage can be suppressed by setting the total depth to 0.09 mm or less.

The number of needle punches is preferably 1000 / cm ² or more and 4000 / cm ² or less. By setting the number of punching to 1000 pieces / cm ² or more, denseness can be obtained and high-precision finishing can be obtained. On the other hand, when the number of punching is 4000 / cm ² or less, deterioration of workability, fiber damage, and strength reduction can be prevented. A more preferable range of the number of punching is 1500 / cm ² or more and 3500 / cm ² or less.

  Moreover, when performing a water jet punch process, it is preferable to perform water in the state of a columnar flow. Preferably, water is ejected from a nozzle having a diameter of 0.05 to 1.0 mm at a pressure of 1 to 60 MPa.

It is preferable that the apparent density of the nonwoven fabric made of ultrafine fiber-generating fibers after needle punching or water jet punching is 0.15 g / cm ³ or more and 0.35 g / cm ³ or less. By setting the apparent density to 0.15 g / cm ³ or more, the polishing pad is excellent in form stability and dimensional stability, and it is possible to suppress the occurrence of processing unevenness and scratch defects during polishing. On the other hand, when the apparent density is 0.35 g / cm ³ or less, a sufficient space for applying the polyurethane elastomer can be maintained.

  From the viewpoint of densification, the nonwoven fabric made of the ultrafine fiber-generating fibers thus obtained is preferably shrunk by dry heat treatment or wet heat treatment, or both, and further densified. Moreover, you may compress the nonwoven fabric which consists of an ultrafine fiber generation type | mold fiber to a thickness direction by a calendar process etc.

  As the solvent for dissolving the easily soluble polymer (sea component) from the ultrafine fiber-generating fiber, an organic solvent such as toluene or trichloroethylene is used if the sea component is a polyolefin such as polyethylene or polystyrene. If the sea component is polylactic acid or copolymer polyester, an aqueous alkali solution such as sodium hydroxide can be used. Further, the ultrafine fiber generation processing (sea removal treatment) can be performed by immersing a nonwoven fabric made of ultrafine fiber generation type fibers in a solvent and squeezing it.

  In addition, a known apparatus such as a continuous dyeing machine, a vibro-washer type seawater removal machine, a liquid dyeing machine, a Wins dyeing machine, and a jigger dyeing machine can be used for processing to generate ultrafine fibers from ultrafine fiber generating fibers. . The above ultrafine fiber generation processing can be performed before napping treatment.

  The cushion base material layer may be further provided with another elastomer after applying the above-described polyurethane-based elastomer in order to prevent fluff from falling off when forming the polishing pad. As the fluff-off preventing resin, the above-mentioned polyurethane, polyurea, polyurethane-polyurea elastomer, polyacrylic acid, acrylonitrile-butadiene elastomer are used.

  A preferable thickness of the cushion base material is 0.5 mm or more and 1.2 mm or less. The substrate to be polished can be uniformly polished by setting the thickness to 0.5 mm or more. Further, the occurrence of defects on the wafer surface can be suppressed by setting the thickness to 1.2 mm or less.

  In addition, in order to efficiently prevent fluffing with a small amount of elastomer and to maintain the compression characteristics of the cushion base material layer, it is preferable to form a polyurethane-based elastomer layer only on the surface layer portion of the cushion base material layer. It is. As a method of forming a polyurethane elastomer layer only on the surface layer portion on the cushion base material layer, various polyurethane elastomers are in a state of an aqueous emulsion or the like, and a polyurethane elastomer is normally applied to the cushion base material layer after napping. It is preferable to dry after the application by a method such as The reason is that the polyurethane elastomer applied to the cushion base material layer can be actively migrated in the thickness direction by drying, so that more polyurethane elastomer can adhere to the surface layer portion of the cushion base material layer. is there.

  It is important that the adhesive that joins the cushion base material layer and the polishing layer including the foamed polyurethane sheet is made of a material having an elastic modulus of 5.0 MPa to 17.0 MPa and has a thickness of 70 μm to 150 μm. If the elastic modulus of the adhesive is less than 5.0 MPa, the shearing force applied to the polishing layer and the cushion base material layer causes a shift between the polishing layer and the cushion base material layer, resulting in a problem that the number of processed wafers decreases. There is a fear. When the elastic modulus exceeds 17.0 MPa, the polishing pressure applied to the surface of the polishing layer in contact with the wafer is insufficiently deformed in the thickness direction of the cushion base material layer via the adhesive layer, so that the in-plane uniformity of the wafer May be insufficient. A more preferable range of the elastic modulus is 7.0 MPa or more and 15.0 MPa or less. It is preferable that the elastic modulus is 7.0 MPa or more because the polishing layer and the cushion base material layer due to the shearing force applied to the polishing layer and the cushion base material layer can be prevented from shifting, and the number of processed wafers increases. . When the elastic modulus is 15.0 MPa or less, the polishing pressure applied to the surface of the polishing layer in contact with the wafer is sufficiently deformed in the thickness direction of the cushion base material layer via the adhesive layer. It is preferable because it is sufficiently good. When the thickness of the adhesive layer is less than 70 μm, there may be a portion where the adhesive force between the polishing layer and the cushion base material layer is insufficient within the polishing pad surface. When the thickness of the adhesive layer exceeds 150 μm, the polishing pressure applied to the polishing layer in contact with the wafer is not sufficiently deformed in the thickness direction of the cushion base material layer via the adhesive layer, and the wafer in-plane uniformity is There is a risk of getting worse. A more preferable range of the thickness of the adhesive layer is 90 μm or more and 130 μm or less. When the thickness of the adhesive layer is 90 μm or more, the adhesive force between the polishing layer and the cushion base material layer is sufficiently uniform within the polishing pad surface, which is preferable because the number of wafers processed can be increased. When the thickness of the adhesive layer is 140 μm or less, the polishing pressure applied to the polishing layer in contact with the wafer can be sufficiently deformed in the thickness direction of the cushion base material layer through the adhesive layer. Is preferable.

  Specific examples of the adhesive that joins the cushion base layer and the polishing layer including the foamed polyurethane sheet having closed cells include various adhesives such as urethane, epoxy, acrylic, and rubber. In order to bring the elastic modulus of the adhesive into a desired range, it is possible to apply even a mixture of an adhesive and a non-adhesive having a low elastic modulus.

  Among various adhesives, as a specific product name of urethane-based adhesives, “Rubilon (registered trademark) 602”, “Rubilon (registered trademark) 603”, “Rubicoat (registered trademark)” manufactured by Toyo Polymer Co., Ltd. are registered as one-pack type. Trademark) F-7 "," Rubilac (Registered Trademark) 603 "," Rubilac (Registered Trademark) 645E "," Rubilon (Registered Trademark) 101 "," Rubilon (Registered Trademark) Ace "," Rubilon (Registered Trademark) 202 " "Rubilon (Registered Trademark) AAA", "Rubilon (Registered Trademark) R", "Rubilon (Registered Trademark) 101SP", "Rubilon (Registered Trademark) Floor 503", "Rubilon (Registered Trademark) 302", "Rubilon" (Registered trademark) 155 ”, manufactured by Toagosei Co., Ltd.“ PU-3030D ”,“ PU-7000D ”, manufactured by Cemedine Co., Ltd.“ UM700 ”,“ UM700S ”, “UM750”, “UM100”, “UM300HK”, “UM550”, “UM600”, “UM600V”, “UM600VL”, “Takelac (registered trademark) A367H”, “Takelac (registered trademark) A369” manufactured by Mitsui Chemicals Polyurethanes, Inc. "Takenate (registered trademark) A7", "Takenate (registered trademark) A19" and the like.

  For the two-component adhesive, “Lubilon (registered trademark) KA-28, KB-28”, “Lubilon (registered trademark) KA-38, KB48”, “Lubilon (registered trademark) KA-” manufactured by Toyo Polymer Co., Ltd. 42, KB-33 "," RUBILON (registered trademark) KA-10, KB-33ME "," NA-21, NB-29 "," PU-62 A agent, PU-62 B agent "manufactured by Toagosei Co., Ltd. ”,“ PU-9000, PU-171 ”and the like, but are not limited thereto. Specific product names of epoxy adhesives include "Aronmighty (registered trademark) AP-0786", "Alonmighty (registered trademark) AP-3510", "Aronmighty (registered)" manufactured by Toagosei Co., Ltd. Trademark) AP-3513 ", Cemedine Co., Ltd." EP-138 "," EP-170 "," EP-160NL "Two-pack type" Aronmighty (registered trademark) AP-205 "manufactured by Toagosei Co., Ltd. ”,“ Aronmighty (registered trademark) AP-209 ”,“ Aronmighty (registered trademark) AP-317 ”,“ EP-001 ”,“ EP-007 ”,“ EP-330 ”manufactured by Cemedine Co., Ltd., solution Examples of the dilution type include “Aronmighty (registered trademark) AS-60” and “Aronmighty (registered trademark) AS-310” manufactured by Toagosei Co., Ltd., but are not limited thereto. There. Specific names of acrylic adhesives include “Aronmite (registered trademark) X-2100T” manufactured by Toagosei Co., Ltd., “Y-610”, “Y-620” manufactured by Cemedine Co., Ltd. and the like. However, it is not limited to these. Examples of the rubber-based adhesive include “521” and “575” manufactured by Cemedine Co., Ltd. and “Hybon (registered trademark) 1420” manufactured by Hitachi Chemical Co., Ltd., but are not limited thereto.

  As the adhesive, in addition to the above-described ordinary adhesive, a solventless heat-melt adhesive is preferably used from the viewpoint of environment and workability. Depending on the type of heat-melt adhesive, the adhesive is melted at a temperature of about 70 to 130 ° C., applied to one or both of the adherends with a roll coater, etc., and bonded and pressed while sticky. After the treatment or the like, the adhesive is bonded by cooling and solidifying. In some cases, after bonding, the resin is cured by crosslinking reaction in the air or by moisture or moisture of the adherend, thereby increasing the adhesive strength. Specific examples of heat-melt-type adhesives include polyester-based, modified olefin-based, urethane-based adhesives, etc., as described above, types that are cooled and cured after melt bonding, and after melt-bonding / cooling-curing, and further in the air There are two types that crosslink by reacting with moisture. Specific product names of polyester-based heat-melt adhesives include “Aronmelt (registered trademark) PES series” manufactured by Toagosei Co., Ltd., and specific product names of modified olefin-based heat-melt adhesives include Toagosei ( Specific product names of “Aronmelt (registered trademark) PPET series” manufactured by Co., Ltd. and urethane-based heat-melt adhesives are “Aronmelt (registered trademark) R series” manufactured by Toagosei Co., Ltd., and “QR4663” manufactured by Henkel. , “QR4635”, “ARX-1288C2”, “ARX-1288H”, “ARX-1311D”, “ARX-1270”, “ARX1255C1”, “ARX-1308A”, manufactured by Nitta Gelatin Co., Ltd., Hitachi Chemical ( "Hibon (registered trademark) 4812", "Hibon (registered trademark) 4820", "Hibon (registered trademark)" 830 "," Hibon (registered trademark) 4832 "," Hibon (registered trademark) YR713-1W "," Hibon (registered trademark) 4820 "," Hibon (registered trademark) YR346-1 ", manufactured by Mitsui Chemicals Polyurethanes, Inc. “MA-1102W”, “MA-1102S”, “MA-3002T”, “MA-3229”, “MA-1001”, “MA-0110S”, “MA-4008”, “MA-4013”, “MA -4100 "," MA-4014 "," MA-4015 "," MA-5002 "," MA-5203 "," MA-5214 "," MA-5215 "," MA-5310 ", Konishi Co., Ltd. Examples thereof include “KUM3150”, “KUM3150S”, “KUM3200” and the like, but are not limited thereto.

  By attaching a double-sided adhesive tape to the back surface of the lowermost cushion base material layer, a final abrasive product can be obtained. Specific product names of the double-sided adhesive tape include “442JS” manufactured by Sumitomo 3M Limited, “535A” manufactured by Nitto Denko Corporation, “5782W”, “5604TDM” manufactured by Sekisui Chemical Co., Ltd., and Teraoka Co., Ltd. “751”, “758”, “777”, “782”, “761”, “7021”, and the like manufactured by Seisakusho are listed, but not limited thereto.

  Even if the polishing layer and the cushion base material layer are in the form of a single sheet or a roll in which the sheet is continuously wound, there is no particular problem.

  Moreover, after laminating the polishing layer and the cushion base material layer, it is preferable to attach a double-sided pressure-sensitive adhesive tape for fixing the polishing surface plate to the opposite surface of the cushion base material layer. The material and the bonding method of the double-sided pressure-sensitive adhesive tape are as described above and are not particularly limited.

  In the polishing pad, in order to obtain stable polishing characteristics, it is preferable that grid-like grooves and concentric grooves are formed on the surface of the polishing layer having the upper polyurethane foam sheet. In addition, when used in a polishing apparatus with an optical end point detection function capable of observing the surface state of the polishing substrate during polishing, a through-hole penetrating from the back surface to the surface of the polishing pad is in contact with the polishing substrate. Can be used in open shapes. In that case, the through-hole may be used by inserting a block-shaped resin plate made of acrylonitrile butadiene styrene copolymer resin having high transparency.

  The polishing pad is a polishing pad used in the process of mechanically flattening the surface of an insulating layer formed on a semiconductor substrate such as silicon or the surface of a metal wiring, and has good flatness and good in-wafer uniformity. Used as a thing.

  Hereinafter, the details of the present invention will be described with reference to examples. In this example, each characteristic was measured by the following method.

[Micro rubber A hardness]
It is measured with a micro rubber hardness meter “MD-1” of Kobunshi Keiki Co., Ltd. (location: Nishiiri, Shimocho, Kamikyo-ku, Kyoto).

  The configuration of the micro rubber hardness tester “MD-1” is as follows.

1.1 Sensor part (1) Load system: Cantilever leaf spring (2) Spring load: 0 point / 2.24 gf, 100 point / 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 drive unit (1) Drive system: vertical drive by stepping motor, descent speed control by air damper (2) vertical 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 XY table and micrometer head, stroke: 15 mm for both X axis and Y axis
(3) Level adjuster: Level adjustment body legs and round level

[Test wafer for evaluating the flatness and in-plane uniformity of tungsten wiring]
Grooves having a width of 10 μm and a depth of 0.7 μm are formed on an 8-inch silicon wafer with an oxide film (oxide film thickness: 2 μm) at intervals of 10 μm. A test wafer for evaluating the flatness (dishing) and in-plane uniformity of tungsten wiring was formed by forming 150 mm of TiN on this and 8000 mm of tungsten by sputtering.

[Preparation of polishing pad and polishing machine and evaluation of flatness, in-plane uniformity and life]
A desired foamed polyurethane sheet is produced with a desired thickness, and a polishing layer containing the foamed polyurethane sheet is produced. Create a desired cushion substrate layer. The polishing layer and the cushion base material layer are bonded with a desired adhesive, and a double-sided tape (3442, “442J”) is bonded to the back surface, and the polishing layer containing the foamed polyurethane sheet has a width of 2. So-called XY groove processing (lattice groove processing) with 0 mm and a pitch of 15 mm was performed. A part of this polishing pad was penetrated, a transparent block of hard polyurethane was inserted into a part corresponding to the penetrated polishing layer, and the polishing pad was cut into a size of 508 mm in diameter to make a polishing pad capable of detecting the end point. This polishing pad was affixed to a surface plate of a polishing machine (manufactured by AMAT, MIRRA-3400). Using a diamond dresser (“80 grid type”) manufactured by Cesol, rotating at a pressing pressure of 7 lbf, a dresser rotating speed of 101 rpm, and a platen rotating speed of 108 rpm, and supplying pure water at 100 cc / min, the initial polishing pad for 20 minutes Dressed. A test wafer for evaluating the flatness (dishing) and in-plane uniformity of tungsten wiring is set in a polishing machine, and tungsten polishing is performed by mixing Cabot slurry ("SEMI-SPERSE W-2000") with 2% hydrogen peroxide solution. While supplying the slurry for polishing onto the polishing pad at 110 cc / min, the polishing pressure is 4.9 psi, the platen rotation speed is 108 rpm, the polishing head rotation speed is 106 rpm, and the reflected light signal from the end point detector is observed. However, after it was confirmed that tungsten could be removed, the polishing was stopped after further overpolishing for 16 seconds. The polished test wafer thus obtained was washed and dried, and dishing with a width of 10 μm was evaluated with a P-7 profiler manufactured by KLA-TENCOR. There are seven wafer evaluation positions (X, Y): (0 mm, 0 mm), (0 mm, ± 50 mm), (0 mm, ± 90 mm) (± 50 mm, 0 mm), (± 90 mm, 0 mm) The average value of each dishing amount was used as an index of flatness, and a number obtained by dividing the difference between the maximum value and the minimum value of each dishing amount by the average value by 100 was used as an in-plane uniformity index. After preparing an 8-inch oxide film wafer and polishing 500 wafers under the above polishing conditions, a test wafer for evaluating the flatness (dishing) and in-plane uniformity of new tungsten wiring is polished under the above polishing conditions. The dishing amount is measured at all the measurement points, and the in-plane uniformity, which is a number obtained by multiplying the average value of the dishing amount and the difference between the maximum and minimum values by the average value, multiplied by 100, is the initial wafer level. The lifespan was determined based on whether there was any change in characteristics.

[Melting point]
Using a Perkin Elmaer DSC-7, the peak top temperature indicating the melting of the polymer at 2nd run was taken as the melting point of the polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg.

[Melt flow rate (MFR)]
4-5 g of sample pellets are put in a cylinder of an MFR meter electric furnace and the amount of resin extruded in 10 minutes under the conditions of a load of 2160 gf and a temperature of 285 ° C. using a Toyo Seiki melt indexer (S101) [g / 10 minutes]. The same measurement was repeated 3 times, and the average value was defined as MFR.

[Average single fiber diameter and average single fiber diameter CV of ultrafine fibers]
A cross section perpendicular to the thickness direction of the polishing pad including the ultrafine fibers was observed at 3000 times using a scanning electron microscope (VE-7800 manufactured by SEM KEYENCE), and was randomly extracted within a field of view of 30 μm × 30 μm. The diameter of 50 single fibers was measured in units of μm with 3 significant figures. However, this was performed at three locations, the diameter of a total of 150 single fibers was measured, and the third significant digit was rounded off to calculate the average value with two significant digits. When fibers having a fiber diameter exceeding 10 μm are mixed, the fibers are excluded from the measurement target of the average fiber diameter as not corresponding to the ultrafine fibers. When the ultrafine fiber has an irregular cross section, first, the cross-sectional area of the single fiber was measured, and the diameter of the single fiber was calculated by calculating the diameter when the cross section was assumed to be circular. A standard deviation value and an average value were calculated using this as a population. A value obtained by dividing the standard deviation value by the average value expressed as a percentage [%] was defined as an average single fiber diameter CV.

[Compression rate of cushion base material]
An initial thickness T0 [mm] is measured by applying 50 [g / cm ² ] to the cushion base material with an initial load. Next, a thickness after loading T1 [mm] is measured by applying a load of 300 [g / cm ² ]. Compression ratio = (T0−T1) / T0 × 100 [%] The value calculated by the calculation formula.

[Elastic modulus of adhesive]
The measurement was carried out under the following conditions using a Tensilon universal tester RTC-1250A manufactured by Orientec.

(Average value of 5 measurements)
・ Specimen shape: rectangle with a predetermined thickness of 20 mm width and sample length of 60 mm ・ Initial chuck distance of 40 mm
Test speed: 100 cm / min. The elastic modulus when the strain was 25% was defined as the elastic modulus of the adhesive.

[Example 1]
(Cushion base material layer)
(Sea component and island component)
Polyethylene terephthalate (PET) having a melting point of 260 ° C. and MFR 46.5 was used as an island component, and polystyrene of MFR 117 having a melting point of 85 ° C. was used as a sea component.

(Spinning / drawing)
Using the above-mentioned island component and sea component, using a 16 island / hole sea-island type composite die, spinning temperature 285 ° C., island / sea mass ratio 80/20, discharge rate 1.2 g / min, hole and spinning speed 1100 m The composite fiber was melt-spun under the conditions of / min. Next, it is stretched by 2.8 times by steam stretching, crimped using an indentation-type crimper, cut, and cut into raw cotton of a sea-island composite fiber having a composite fiber fineness of 4.2 dtex and a fiber length of 51 mm Got.

(Extra-fine fiber generation type nonwoven fabric)
A laminated fiber web was formed through the carding process and the cross wrapping process using the raw cotton of the above-mentioned sea-island type composite fibers. Subsequently, the obtained laminated fiber web was needle-punched at a needle depth of 6 mm and a number of punches of 3000 / cm ² using a needle punch machine in which one needle having a total barb depth of 0.08 mm was implanted, and the basis weight was 815 g. A non-woven fabric made of ultrafine fiber-generating fibers with a / m ² apparent density of 0.225 g / cm ³ was produced.

(Polyurethane impregnation)
The nonwoven fabric composed of the above-mentioned ultrafine fiber-generating fiber is subjected to a hot water shrinkage treatment at a temperature of 95 ° C., and after applying polyvinyl alcohol to 26% by mass with respect to the fiber mass, after drying, the sea component polystyrene is obtained using trichlorethylene. After dissolution and removal, the fabric was dried to obtain a nonwoven fabric composed of ultrafine fiber bundles. The nonwoven fabric composed of the ultrafine fiber bundle thus obtained is made of polyurethane having a polymer diol of 75% by mass of a polyether diol and 25% by mass of a polyester diol, and the solid content mass ratio of the ultrafine fiber to the polyurethane is 22% by mass. The polyurethane was coagulated with a 30% DMF aqueous solution at a liquid temperature of 35 ° C. and treated with hot water at a temperature of about 85 ° C. to remove DMF and polyvinyl alcohol. Then, the sheet base material was obtained by half-cutting in the thickness direction by a half-cutting machine having an endless band knife. The semi-finished surface of the obtained sheet base material was buffed and ground to form a raised surface.

(Applying anti-fluff agent)
An 8.5% solution of nitrile butadiene rubber (NBR) (Nipol LX511A manufactured by Nippon Zeon Co., Ltd.) resin is added to the above sheet base material so that the mass ratio of the solid content of the sheet base material and NBR is 3.1% by weight. And dried at a temperature of 170 ° C. to obtain a cushion base material. The obtained cushion base material has an average single fiber diameter of 4.4 μm, an average single fiber diameter CV value of 6.2%, a thickness of 0.90 mm, a basis weight of 370 g / m ² , and an apparent density of 0. .343 g / cm ³ , and the compression rate was 7.8%.

(Creation of foamed polyurethane sheet)
1250 parts by weight of toluene diisocyanate, 300 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, 2000 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 990, and 205 parts by weight of diethylene glycol were added and reacted at 75 ° C. for 6 hours to give an isocyanate-terminated prepolymer. A polymer was obtained. 110 parts by weight of the prepolymer and 25 parts by weight of 4,4′diphenylmethane diisocyanate were added and mixed in the polymerization vessel, and the temperature was adjusted to 75 ° C. and degassed under reduced pressure. Then, it stirred violently for about 10 minutes so that a bubble might be taken in in the reaction system with the rotation speed of 700 rpm using the stirring blade. 45 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. was added thereto. The mixed solution was stirred for about 60 seconds, and then poured into a pan-shaped open mold (casting container). When the fluidity of the mixed solution disappeared, it was placed in an oven and post-cured at 95 ° C. for 20 hours to obtain a polyurethane foam block. The polyurethane foam block heated to about 80 ° C. was sliced using a slicer (manufactured by Mitsubishi Materials Corporation) to obtain a polyurethane foam urethane sheet having a thickness of 1.5 mm. The micro rubber A hardness was 97 degrees and the density was 0.8 [g / cm ³ ].

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 110 and 55.0 parts by weight of 4,4′-diphenylmethane diisocyanate obtained by the reaction of adipic acid, ethylene glycol and 1,4-butanediol were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 7.9 parts by weight of 1,4-butanediol (hydroxyl value 1245), 6.2 parts by weight of ε-caprolactam as a blocking agent, and 2.4 parts by weight of propylene glycol, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A film adhesive was obtained. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 2]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 0.60 mm was used.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 110 obtained by the reaction of adipic acid, ethylene glycol and 1,4-butanediol and 40.0 parts by weight of 4,4′-diphenylmethane diisocyanate were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 7.9 parts by weight of 1,4-butanediol (hydroxyl value 1245), 6.2 parts by weight of ε-caprolactam as a blocking agent, and 2.4 parts by weight of propylene glycol, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer was crushed into flakes by a pulverizer, and then the resin composition prepared in Example 1 was used by using the flaky resin composition in an extrusion molding machine having a die temperature of 125 ° C. Extrusion was performed into a film having a thickness of 75 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 7.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 3]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 0.51 mm was used.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The resin composition prepared in Example 1 was extruded into a film having a thickness of 145 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 4]
(Cushion base material layer)
The average single fiber diameter of the ultrafine fibers was 4.4 μm and the average single fiber diameter was the same as in Example 1 except that the polyurethane was added so that the solid mass ratio of the ultrafine fibers to the polyurethane was 23% by mass. A cushion base material layer having a CV value of 6.2%, a thickness of 1.10 mm, a basis weight of 375 g / m ² , an apparent density of 0.347 g / cm ³ , and a compression rate of 6.9% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 110 and 75.0 parts by weight of 4,4′-diphenylmethane diisocyanate obtained from the reaction of adipic acid, ethylene glycol and 1,4-butanediol were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 7.9 parts by weight of 1,4-butanediol (hydroxyl value 1245), 6.2 parts by weight of ε-caprolactam as a blocking agent, and 2.4 parts by weight of propylene glycol, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer was crushed into flakes by a pulverizer, and then the resin composition prepared in Example 1 was used by using the flaky resin composition in an extrusion molding machine having a die temperature of 125 ° C. Using a extrusion machine with a die temperature of 125 ° C., it was extruded into a film having a thickness of 100 μm to obtain a film adhesive. The elastic modulus of this adhesive was 15.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 5]
(Cushion base material layer)
The average single fiber diameter of the ultrafine fibers was 4.4 μm and the average single fiber diameter was the same as in Example 1 except that the polyurethane was applied so that the solid mass ratio of the ultrafine fibers to the polyurethane was 29% by mass. A cushion base material layer having a CV value of 6.2%, a thickness of 1.19 mm, a basis weight of 379 g / m ² , an apparent density of 0.351 g / cm ³ , and a compressibility of 2.2% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The resin composition prepared in Example 1 was extruded into a film having a thickness of 90 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 6]
(Cushion base material layer)
In the spinning process, the same process as in Example 4 was performed except that a 36 island / hole sea-island type composite die was used and the average single fiber diameter of the ultrafine fibers was 3.1 μm, and the fiber diameter CV value was 5. A cushion base material layer having a thickness of 2%, a thickness of 1.20 mm, a basis weight of 370 g / m ² , an apparent density of 0.343 g / cm ³ , and a compression rate of 5.4% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 7]
(Cushion base material layer)
In the spinning process, the average single fiber diameter of the ultrafine fibers is set to 3.6 μm using a 36 island / hole sea-island type composite die, and the solid content mass ratio of polyurethane in the base material for the polishing pad is 26% by mass. The fiber diameter CV value is 5.4%, the thickness is 0.95 mm, the basis weight is 368 g / m ² , the apparent density is 0.341 g / cm ³ , and the compression is performed in the same manner as in Example 4 except that the above is applied. A cushion base material layer having a rate of 5.2% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The resin composition prepared in Example 1 was extruded into a film having a thickness of 130 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 8]
(Cushion base material layer)
The average single fiber diameter CV value was 5.5%, the thickness was 0.65 mm, and the basis weight was 373 g / m ^{2 in the same} manner as in Example 4 except that the average single fiber diameter of the ultrafine fibers was 5.3 μm. A cushion base material layer having an apparent density of 0.345 g / cm ³ and a compression rate of 4.9% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 9]
(Cushion base material layer)
In the spinning process, the average single fiber diameter of the ultrafine fibers is set to 5.9 μm using a 16 island / hole sea-island type composite die, and the mass ratio of the solid content of the sheet base material and NBR is 3.2 mass%. The average single fiber diameter CV value was 5.6%, the thickness was 0.93 mm, the weight per unit area was 373 g / m ² , and the apparent density was 0.345 g / cm ³ except in the same manner as in Example 4. A cushion base material layer having a compression rate of 4.5% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 10]
(Cushion base material layer)
In the spinning process, the average single fiber diameter of ultrafine fibers is set to 6.2 μm using a 16 island / hole sea-island type composite die, and the mass ratio of the solid content of the sheet base material and NBR is 3.3 mass%. The average single fiber diameter CV value was 5.8%, the thickness was 0.73 mm, the basis weight was 372 g / m ² , and the apparent density was 0.344 g / cm ^{3 in} the same manner as Example 4 except for the addition. A cushion base material layer for a polishing pad having a compression rate of 4.2% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 11]
(Cushion base material layer)
The average single fiber diameter of the ultrafine fibers is 7.5 μm, polyurethane is applied so that the solid content mass ratio of the ultrafine fibers and polyurethane is 25% by mass, and the mass ratio of the solid content of the sheet base material and NBR is 1.2. The average single fiber diameter CV value was 6.2%, the thickness was 0.84 mm, the weight per unit area was 368 g / m ² , and the apparent density was 0, except that it was applied so as to be mass%. .341g / cm ^3, the compression ratio has created a 3.5% of the cushion base layer.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 12]
(Cushion base material layer)
In the same manner as in Example 11, except that the average single fiber diameter of the ultrafine fibers was 7.9 μm and the mass ratio of the solid content of the sheet substrate and NBR was 4.5% by mass, A cushion base material layer for a polishing pad having a fiber diameter CV value of 6.1%, a thickness of 0.95 mm, a basis weight of 374 g / m ² , an apparent density of 0.346 g / cm ³ , and a compressibility of 3.1%. Created.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 13]
(Cushion base material layer)
In the spinning process, the discharge rate is adjusted, the spinning speed is set to 600 m / min, and polyurethane is applied so that the solid content mass ratio of polyurethane in the polishing pad substrate is 25% by mass. The average single fiber diameter CV value is 11.2%, the thickness is 0.99 mm, and the basis weight is 374 g, except that the mass ratio is 3.7 mass%. A cushion base material layer having an / m ² apparent density of 0.346 g / cm ³ and a compressibility of 3.1% was prepared.

(Creation of foamed polyurethane sheet)
The same one as that prepared in Example 1 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.
(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 14]
(Cushion base material layer)
The same cushion base layer as in Example 13 was used.

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creation of foamed polyurethane sheet)
900 parts by weight of toluene diisocyanate, 250 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, 2000 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 1500, and 180 parts by weight of diethylene glycol were added and reacted at 80 ° C. for 6 hours to give an isocyanate-terminated prepolymer. A polymer was obtained. 110 parts by weight of the prepolymer and 20 parts by weight of 4,4′diphenylmethane diisocyanate were added and mixed in the polymerization vessel, adjusted to 80 ° C. and degassed under reduced pressure. Then, it stirred violently for about 10 minutes so that a bubble might be taken in in a reaction system with the rotation speed of 800 rpm using the stirring blade. Thereto was added 35 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. The mixed solution was stirred for about 60 seconds, and then poured into a pan-shaped open mold (casting container). When the fluidity of the mixed solution disappeared, it was placed in an oven and post-cured at 95 ° C. for 20 hours to obtain a polyurethane foam block. The polyurethane foam block heated to about 80 ° C. was sliced using a slicer (manufactured by Mitsubishi Materials Corporation) to obtain a polyurethane foam urethane sheet having a thickness of 1.5 mm. The micro rubber A hardness was 83 degrees and the density was 0.8 [g / cm ³ ].

[Example 15]
(Cushion base material layer)
The same cushion base layer as in Example 13 was used.

(Creation of foamed polyurethane sheet)
The same as in Example 14 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 70 and 35.0 parts by weight of 4,4′-diphenylmethane diisocyanate obtained from the reaction of adipic acid, ethylene glycol and 1,4-butanediol were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this, 5.0 parts by weight of 1,4-butanediol (hydroxyl value 1245), 3.9 parts by weight of ε-caprolactam as a blocking agent, and 1.5 parts by weight of propylene glycol were added and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A film adhesive was obtained. The elastic modulus of this adhesive was 5.1 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 16]
(Cushion base material layer)
The same cushion base layer as in Example 13 was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 150 and 75.0 parts by weight of 4,4′-diphenylmethane diisocyanate obtained from the reaction of adipic acid, ethylene glycol and 1,4-butanediol were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 10.7 parts by weight of 1,4-butanediol (hydroxyl value 1245), 8.4 parts by weight of ε-caprolactam and 3.3 parts by weight of propylene glycol as a blocking agent, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A film adhesive was obtained. The elastic modulus of this adhesive was 16.8 MPa.

(Creating a polishing pad)
When the adhesive is sandwiched between the foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 17]
(Cushion base material layer)
The same cushion base material layer as in Example 1 was used.

(Creation of foamed polyurethane sheet)
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 with a RIM molding machine. The foamed polyurethane sheet (micro rubber A hardness = 37 degrees, density: 0.74 [g / cm ³ ]) having a thickness of 2.2 mm was prepared by discharging into a mold and performing pressure molding. The foamed polyurethane sheet is immersed in methyl methacrylate to which 0.1 part by weight of azobisisobutylnitrile is added for 15 minutes. The polyurethane foam sheet swelled with methyl methacrylate is sandwiched between glass plates and heated at 65 ° C. for 6 hours, and then heated at 100 ° C. for 3 hours. Remove from the glass plate after heating and vacuum dry at 50 ° C. The obtained rigid foam sheet is ground on both sides to produce a rigid foam polyurethane sheet having a thickness of 1.2 mm. The obtained polyurethane foam had a micro rubber A hardness of 93 degrees, a density of 0.81 [g / cm ³ ], and a polymethyl methacrylate content of 40% by weight.

(Create adhesive)
The same adhesive as in Example 16 was used.

(Creating a polishing pad)
The adhesive is sandwiched between the hard foamed polyurethane sheet and the cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and the hard transparent polyurethane block is partially penetrated. Then, an XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Example 18]
(Cushion base material layer)
The same one as that prepared in Example 1 was used.

(Creation of foamed polyurethane sheet)
Add 800 parts by weight of toluene diisocyanate, 200 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, 2000 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 2000, and 205 parts by weight of diethylene glycol, and react for 6 hours at 80 ° C. A polymer was obtained. 110 parts by weight of the prepolymer and 15 parts by weight of 4,4′diphenylmethane diisocyanate were added to the polymerization vessel, mixed, adjusted to 75 ° C. and degassed under reduced pressure. Then, it stirred violently for about 10 minutes so that a bubble might be taken in in the reaction system with the rotation speed of 700 rpm using the stirring blade. 30 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. was added thereto. The mixed solution was stirred for about 60 seconds, and then poured into a pan-shaped open mold (casting container). When the fluidity of the mixed solution disappeared, it was placed in an oven and post-cured at 95 ° C. for 20 hours to obtain a polyurethane foam block. The polyurethane foam block heated to about 80 ° C. was sliced using a slicer (manufactured by Mitsubishi Materials Corporation) to obtain a polyurethane foam urethane sheet having a thickness of 1.5 mm. The micro rubber A hardness was 75 degrees and the density was 0.7 [g / cm ³ ].

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. Further, it can be seen that the life is good because the flatness and in-plane uniformity after 500 polishing are small.

[Comparative Example 1]
(Cushion base material layer)
The average single fiber diameter CV value was 6.3%, the thickness was 0.90 mm, and the basis weight was 371 g, except that the average single fiber diameter of the ultrafine fibers was 2.8 μm in the spinning process. A cushion base material layer having an / m ² apparent density of 0.344 g / cm ³ and a compression rate of 5.7% was prepared.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
What was created in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. However, since the in-plane uniformity after polishing 500 sheets is greatly deteriorated, there is a problem that the life is short.

[Comparative Example 2]
(Cushion base material layer)
The average single fiber diameter CV value was 6.5%, the thickness was 0.90 mm, and the basis weight was 365 g in the same manner as in Example 4 except that the average single fiber diameter of the ultrafine fibers was 8.5 μm in the spinning process. A cushion base material layer having an / m ² apparent density of 0.338 g / cm ³ and a compressibility of 5.0% was prepared.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
What was created in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation result of the obtained polishing pad has a large in-plane variation in dishing amount, and thus the in-plane uniformity is poor.

[Comparative Example 3]
(Cushion base material layer)
Polyurethane was applied so that the solid mass ratio of polyurethane in the polishing pad substrate was 18% by mass, and the mass ratio of the solid content of the sheet substrate and NBR was 3.2% by mass. In the same manner as in Example 1, the fiber diameter CV value was 6.2%, the thickness was 0.90 mm, the basis weight was 362 g / m ² , the apparent density was 0.335 g / cm ³ , and the compression rate was 8. A 2% cushion substrate layer was created.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
What was created in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. However, since the in-plane uniformity after polishing 500 sheets is greatly deteriorated, there is a problem that the life is short.

[Comparative Example 4]
(Cushion base material layer)
Polyurethane was applied so that the solid content mass ratio of polyurethane in the polishing pad substrate was 32% by mass, and the mass ratio of the solid content of the sheet substrate and NBR was 3.3% by mass. The average single fiber diameter CV value was 6.2%, the thickness was 0.90 mm, the basis weight was 379 g / m ² , the apparent density was 0.351 g / cm ³ , and the compression rate was the same as in Example 1. A 1.9% cushion substrate layer was created.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
What was created in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have large in-plane variations in dishing amount and poor in-plane uniformity.

[Comparative Example 5]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 0.90 mm was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
The flaky resin composition prepared in Example 1 was extruded into a film having a thickness of 62 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad showed poor flatness as the dishing amount, large in-plane variation in the dishing amount, and poor in-plane uniformity.

[Comparative Example 6]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 0.90 mm was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
The flaky resin composition prepared in Example 1 was extruded into a film having a thickness of 155 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad showed poor flatness as the dishing amount, large in-plane variation in the dishing amount, and poor in-plane uniformity.

[Comparative Example 7]
(Cushion base material layer)
The same one used in Example 1 was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 55 and 25.0 parts by weight of 4,4′-diphenylmethane diisocyanate obtained from the reaction of adipic acid, ethylene glycol and 1,4-butanediol were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 7.9 parts by weight of 1,4-butanediol (hydroxyl value 1245), 6.2 parts by weight of ε-caprolactam as a blocking agent, and 2.4 parts by weight of propylene glycol, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A film adhesive was obtained. The elastic modulus of this adhesive was 4.8 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad have good flatness as the dishing amount, and since the in-plane variation of the dishing amount is small, the in-plane uniformity is also good. However, since the in-plane uniformity after polishing 500 sheets is greatly deteriorated, there is a problem that the life is short.

[Comparative Example 8]
(Cushion base material layer)
The same one used in Example 1 was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
100 parts by weight of a polyester diol having a hydroxyl value of 200 obtained from the reaction of adipic acid, ethylene glycol and 1,4-butanediol and 100.0 parts by weight of 4,4′-diphenylmethane diisocyanate were reacted at 80 ° C. for 2 hours, A urethane prepolymer having an isocyanate group at the terminal was obtained. To this was added 7.9 parts by weight of 1,4-butanediol (hydroxyl value 1245), 6.2 parts by weight of ε-caprolactam as a blocking agent, and 2.4 parts by weight of propylene glycol, and reacted at 120 ° C. for 4 hours. To obtain a blocked urethane prepolymer. The obtained blocked urethane prepolymer is crushed into flakes by a pulverizer, and then the flaky resin composition is extruded into a film having a thickness of 100 μm using an extruder with a die temperature of 125 ° C. A film adhesive was obtained. The elastic modulus of this adhesive was 17.4 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad are poor in flatness as the dishing amount, and the in-plane uniformity is also poor because the dishing amount has a large in-plane variation.

[Comparative Example 9]
(Cushion base material layer)
The same one as that prepared in Example 1 was used.

(Creation of foamed polyurethane sheet)
700 parts by weight of toluene diisocyanate, 150 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, 2000 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 2500, and 205 parts by weight of diethylene glycol were added and reacted at 80 ° C. for 6 hours to give an isocyanate-terminated prepolymer. A polymer was obtained. 110 parts by weight of the prepolymer and 12 parts by weight of 4,4′diphenylmethane diisocyanate were added to the polymerization vessel and mixed, adjusted to 75 ° C. and degassed under reduced pressure. Then, it stirred violently for about 10 minutes so that a bubble might be taken in in the reaction system with the rotation speed of 700 rpm using the stirring blade. Thereto was added 25 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. The mixed solution was stirred for about 60 seconds, and then poured into a pan-shaped open mold (casting container). When the fluidity of the mixed solution disappeared, it was placed in an oven and post-cured at 95 ° C. for 20 hours to obtain a polyurethane foam block. The polyurethane foam block heated to about 80 ° C. was sliced using a slicer (manufactured by Mitsubishi Materials Corporation) to obtain a polyurethane foam urethane sheet having a thickness of 1.5 mm. The micro rubber A hardness was 67 degrees, and the density was 0.7 [g / cm ³ ].

(Create adhesive)
The same one as that prepared in Example 1 was used.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad are poor in flatness as the dishing amount, and the in-plane uniformity is also poor because the dishing amount has a large in-plane variation.

[Comparative Example 10]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 0.43 mm was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
The flaky resin composition prepared in Example 1 was extruded into a film having a thickness of 100 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation results of the obtained polishing pad showed good flatness as the dishing amount, but the in-plane variation of the dishing amount was large and the in-plane uniformity was poor.

[Comparative Example 11]
(Cushion base material layer)
The same production method as in Example 1 with a thickness of 1.25 mm was used.

(Creation of foamed polyurethane sheet)
The same as in Example 1 was used.

(Create adhesive)
The flaky resin composition prepared in Example 1 was extruded into a film having a thickness of 100 μm using an extrusion molding machine having a die temperature of 125 ° C. to obtain a film adhesive. The elastic modulus of this adhesive was 9.0 MPa.

(Creating a polishing pad)
The above-mentioned foamed polyurethane sheet is sandwiched between the above-mentioned cushion base material layer and pressed with a press at 120 ° C., and a double-sided tape 442J is further bonded to the back side, and a part of the hard transparent polyurethane block is penetrated. The XY groove having a groove pitch of 15 mm, a groove width of 2 mm, and a groove depth of 0.75 mm was formed on the surface of the polishing layer to prepare a polishing pad of 508 mm.

  As shown in Table 1, the evaluation result of the obtained polishing pad has poor flatness as the dishing amount. The in-plane variation in dishing amount was small and the in-plane uniformity was good.

  The polishing pad according to the present invention can be widely used in the process of mechanically flattening the surface.

Claims (5)

  Microfiber A Ultrafine fiber bundle containing a polishing layer containing a foamed polyurethane sheet having a hardness of 70 degrees or more and a polyurethane elastomer of 20% by mass to 30% by mass and having an average single fiber diameter of 3.0 μm or more and 8.0 μm or less A polishing pad having a structure in which an adhesive layer made of a material having an elastic modulus of 5.0 MPa or more and 17.0 MPa or less and having a thickness of 70 μm or more and 150 μm or less is interposed between the cushion base material layer made of the nonwoven fabric of .   The polishing pad according to claim 1, wherein the polyurethane rubber sheet has a micro rubber A hardness of 80 degrees or more.   The polishing pad according to claim 1, wherein the adhesive layer is made of a material having an elastic modulus of 7.0 MPa to 15.0 MPa, and the thickness of the adhesive layer is 90 μm to 130 μm.   The polishing pad of Claims 1-3 whose compression rate of the said nonwoven fabric is 2% or more and 8% or less.   The polishing pad of Claims 1-4 whose thickness of the said nonwoven fabric is 0.5 mm or more and 1.2 mm or less.