TWI787420B - Polishing pad - Google Patents

Abstract

The present invention provides a high grinding rate, and can obtain high flatness (edge less edge rounding) excellent polishing pad. The present invention uses a polishing pad, which is a hardened product of a urethane resin composition containing a main ingredient (i) including a urethane prepolymer (A), and a hardener (ii). The prepolymer (A) is a reaction of a composition containing a polyol component (a) including a polyol (a1) with a molecular weight of 300 or more and a short-chain diol (a2) with a molecular weight of less than 300, and a polyisocyanate (b) The latter product has an isocyanate group at the end, and the polyol component (a) contains 40% by mass to 90% by mass of polytetramethylene glycol and 1% by mass or more of short-chain diol (a2), The cured product has a peak value of tanδ in the range of 120°C to 200°C, and the peak value of tanδ in the range of 120°C to 200°C is 0.18 or higher.

Description

Polishing pad

The invention relates to a polishing pad and a urethane resin composition for the polishing pad.

In particular, the present invention relates to a polishing pad that can be preferably used in polishing optical lenses, glass substrates, silicon wafers, semiconductor devices, etc., a method for manufacturing the polishing pad, and a polishing method.

Optical lenses, glass substrates for liquid crystal displays (LCD), glass substrates for hard disk drives (hard disk drives, HDD), silicon wafers, semiconductor devices, etc. require a high level of polishing efficiency or non-conductive Scratchability.

In particular, in the above-mentioned semiconductor devices, along with the rapid increase in the integration level of semiconductor circuits, miniaturization and multi-layer wiring for the purpose of high density are continuously promoted, and a further higher level of surface flatness is required on the processed surface and High grinding efficiency. Moreover, in the said glass substrate for liquid crystal displays, along with the enlargement of a liquid crystal display, the surface flatness of the higher level of a processed surface and high polishing efficiency are also required. In this way, the requirement for surface flatness of the processed surface is increased to a higher level, and the required performance such as the polishing efficiency in the polishing process is further improved.

Therefore, in the manufacturing process of optical lenses, semiconductor devices, and LCDs, chemical mechanical polishing (CMP) (Chemical Mechanical Polishing) is widely used as a polishing method capable of forming a surface having excellent flatness.

In the above-mentioned CMP method, a free abrasive method is generally employed in which a slurry (polishing liquid) in which abrasive grains (abrasive grains) are dispersed in an alkaline solution or an acidic solution is supplied and ground during polishing. That is, the object to be polished (the processed surface) is planarized by the mechanical action of the abrasive grains in the slurry and the chemical action with an alkaline solution or an acid solution. Here, along with the high level of flatness required for the processed surface, polishing performance such as polishing precision and polishing efficiency required by the CMP method, specifically, high polishing rate, non-scratch property, and high flatness are required to increase. As a polishing pad using the free abrasive grain method of the CMP method, for example, a polishing pad with a high polishing speed that is difficult to scratch by controlling specific parameters such as hardness or wear or relaxation time or elastic coefficient is proposed (refer to Patent Document 1 , Patent Document 2). In addition, for example, a urethane polishing pad having a specific composition such as ethylene glycol monophenyl ether is excellent in dressing properties (shear rate) (see Patent Document 3). In addition, for example, a urethane polishing pad that forms a macroscopic phase-separated structure due to the compatibility of polyester polyols and polyether polyols used as raw materials has a high polishing rate and excellent stability (see Patent Document 4 , Patent Document 5). In addition, for example, a polishing pad whose material composition is specified for a specific cell diameter or storage modulus of elasticity has a high polishing speed and an excellent break-in time (see Patent Document 6).

As mentioned above, there is a strong demand from the industry for a high-level high-polishing rate, low-scratch property, and high-flatness polishing pad that satisfies the requirements of high-precision polishing, and various attempts have been made, but the actual situation is that it has not yet been achieved. Find. [Prior art literature]

[Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2014-111296 [Patent Document 2] Japanese Patent No. 5710353 [Patent Document 3] Japanese Patent No. 5738731 Publication [Patent Document 4] Japanese Patent No. 5623927 [ Patent Document 5] Japanese Patent Publication No. 5623927 [Patent Document 6] Japanese Patent Publication No. 5393434

[Problem to be Solved by the Invention] The problem to be solved by the present invention is to provide a polishing pad that has a high polishing rate and can obtain a polished object having high flatness (less edge rounding). [Technical means to solve the problem]

The inventors of the present invention conducted diligent research to solve the above-mentioned problems, and as a result, found that by setting the ratio of the composition of the soft segment to the hard segment within a specific range and measuring the dynamic viscoelasticity at a specific Those having a peak value of tanδ greater than or equal to a specific value in a temperature range can provide a polishing pad having a high polishing rate and obtaining a polished object with high flatness (less edge rounding), and thus completed the present invention.

That is, the polishing pad of the present invention is a hardened product of a urethane resin composition containing a main component (i) including a urethane prepolymer (A), and a curing agent (ii). The ester prepolymer (A) is at least a polyol component (a) containing a polyol (a1) having a molecular weight of 300 or more and a short-chain diol (a2) having a molecular weight of less than 300, and a polyisocyanate (b) as raw materials. Part of the product after the reaction has an isocyanate group at the end, the polyol component (a) contains polytetramethylene glycol at a content rate of 40% by mass or more and 90% by mass or less, and the short-chain two The content of the alcohol (a2) in the polyol component (a) is 1% by mass or more, and the hardened product has a temperature of 120°C to 200°C in a dynamic viscoelasticity measurement with a measurement frequency of 1 Hz. There is a peak of tan δ in the range of 120° C. to 200° C. The peak of tan δ is 0.18 or more. [Effect of the invention]

The polishing pad of the present invention can be a polishing pad that has a high polishing rate and can obtain an object to be polished with high flatness (less edge rounding).

The polishing pad of the present invention is a hardened product of a urethane resin composition containing a main ingredient (i) including a urethane prepolymer (A) and a hardener (ii), and the hardened product will be measured In dynamic viscoelasticity measurement with a frequency of 1 Hz, there is a peak of tan δ in the range of 120°C to 200°C, and the peak value of tanδ in the range of 120°C to 200°C is 0.18 or higher. It is considered that in the measurement of dynamic viscoelasticity, the existence of the peak indicates the presence of fine domains having specific viscoelasticity in the cured product, and in the present invention, high Grinding rate and high flatness of the ground object. In the present invention, the fine domains can be generated by specifying the composition of the polyol component (a).

In the dynamic viscoelasticity measurement with a measurement frequency of 1 Hz, the peak value of tanδ is preferably in the range of 120°C to 180°C, more preferably 110°C to 170°C. .

The peak value of tan δ is preferably at least 0.20, more preferably at least 0.25, and still more preferably at least 0.3. The upper limit is not particularly limited, and may be, for example, 1 or less, and further may be 0.8 or less.

In the main ingredient (i), the urethane prepolymer (A) is a reaction product of polyol component (a) and polyisocyanate (b) (polyol component (a) and polyisocyanate The isocyanate (b) is a product after reaction of at least a part of the raw materials), and has an isocyanate group at the terminal.

The polyol component (a) may contain one or two or more polyols, including at least a polyol (a1) with a molecular weight of 300 or more (hereinafter, sometimes simply referred to as "polyol (a1)") and a molecular weight of less than 300. 300 short-chain diol (a2) (hereinafter, sometimes simply referred to as "short-chain diol").

The polyol (a1) may form a soft segment in the obtained polishing pad. The number average molecular weight of the polyol (a1) is preferably at least 700, more preferably at least 1,100, further preferably at least 1,400, and more preferably at most 8,000, more preferably at most 5,000, further preferably at least 3,000 or less, particularly preferably 2,500 or less. In the present specification, the number average molecular weight can be measured by gel permeation chromatography (GPC (gel permeation chromatography) method) using polystyrene as a standard sample. In addition, when two or more polyols are included as the polyol (a1), the number average molecular weight of the polyol (a1) can be based on the number average molecular weight and mass ratio of each polyol as a weighted average to figure it out.

The number of hydroxyl groups contained in the polyol is preferably two or more and five or less.

The polyol (a1) includes polyether polyol (a1-1). Examples of the polyether polyol (a1-1) include polyoxyalkylene polyols obtained by ring-opening polymerization of cyclic ethers, and polyoxyalkylene polyols having two or more groups containing active hydrogen atoms may be used. One or two or more compounds are obtained as starting agents.

The number of carbon atoms of the cyclic ether is preferably 2-10, more preferably 2-6, and still more preferably 2-4. Hydrogen atoms contained in the cyclic ether may be substituted with halogen atoms. As the cyclic ether, one kind or two or more kinds can be used, for example, ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, Epichlorohydrin, tetrahydrofuran, alkylated tetrahydrofuran, etc.

As the initiator, one kind or two or more kinds can be used, for example, ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, Alcohol, 1,6-hexanediol, neopentyl glycol, water and other compounds with two active hydrogen atoms; glycerin, diglycerol, trimethylolethane, trimethylolpropane, hexanetriol, monoethanolamine , diethanolamine, triethanolamine, ethylenediamine, pentaerythritol, sugar, and other compounds having three or more active hydrogen atoms.

The polyether polyol (a1-1) contains at least polytetramethylene glycol. The polytetramethylene glycol contained in the polyol component (a) has a number average molecular weight of 300 or more, preferably 1,100 or more, more preferably 1,300 or more, and preferably 4,000 or less, more preferably It is 3,000 or less, and more preferably 2,500 or less. In the case of including two or more polytetramethylene glycols with different number average molecular weights, the number average molecular weight of polytetramethylene glycol can be based on the number average molecular weight and mass ratio of each polytetramethylene glycol , calculated as a weighted average.

In the polyol component (a), the content of polytetramethylene glycol is not less than 40% by mass, preferably not less than 50% by mass, more preferably not less than 60% by mass, and not more than 90% by mass, Preferably it is 85 mass % or less, More preferably, it is 80 mass % or less. In the polyol (a1), the content of polytetramethylene glycol is preferably more than 50% by mass, more preferably at least 60% by mass, further preferably at least 70% by mass, particularly preferably 75% by mass. Mass % or more and 100 mass % or less. It is particularly preferred that the polyol (a1) is polytetramethylene glycol.

The polyether polyol (a1-1) may also contain polyoxypropylene polyol. The number average molecular weight of the polyoxypropylene polyol is 300 or more, preferably 400 or more, and preferably 5,000 or less, more preferably 2,000 or less, and more preferably 1,000 or less. In the case of including two or more polyoxypropylene polyols with different number average molecular weights, the number average molecular weight of the polyoxypropylene polyols can be determined as a weighted average based on the number average molecular weight and mass ratio of each polyoxypropylene polyol. figured out.

The number of hydroxyl groups contained in the polyoxypropylene polyol is 2 or more, preferably 3 or more, and preferably 5 or less, more preferably 4 or less.

In the case where polyoxypropylene polyol is included, in the polyol (a1), the content of polyoxypropylene polyol is preferably 5 parts by mass or more relative to 100 parts by mass of polytetramethylene glycol, more preferably It is preferably at least 10 parts by mass, more preferably at most 50 parts by mass, more preferably at most 40 parts by mass, further preferably at most 30 parts by mass.

In the polyol (a1), the content of the polyether polyol (a1-1) is preferably at least 80% by mass, more preferably at least 90% by mass, further preferably at least 95% by mass, and the upper limit is 100% by mass.

The polyol (a1) may contain other polyols (a1-2) in addition to the polyether polyol (a1-1). As the other polyol (a1-2), one kind or two or more kinds can be used, for example, polyester polyol, polycarbonate polyol, polybutadiene polyol, polyacrylic polyol, polyisoprene polyol, Diene polyols, etc.

As the polyester polyol, one kind or two or more kinds can be used, for example, polyester polyol obtained by reacting low molecular weight polyol and polycarboxylic acid; cyclic ester such as ε-caprolactone Polyester polyols obtained by ring-opening polymerization of compounds; polyester polyols obtained by copolymerizing these compounds; and the like.

As the low-molecular-weight polyol, one or more types can be used, for example, polyols having a molecular weight of 50 or more and less than 300, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, 1,3-butanediol and other aliphatic polyols; cyclohexanedimethanol and other polyols with alicyclic structure; bisphenol A and A polyhydric alcohol having an aromatic ring such as bisphenol F. Among them, 1,6-hexanediol and neopentyl glycol are preferable.

As the polycarboxylic acid which can be used in the production of the polyester polyol, one kind or two or more kinds can be used, for example, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, etc. Aliphatic polycarboxylic acids; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid; anhydrides or esterified products thereof, and the like.

The polycarbonate polyol is obtained by esterifying carbonic acid and a carbonate ester with a polyol. As the polyhydric alcohol, one kind or two or more kinds can be used, for example, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, Polyoxypropylene glycol, polytetramethylene glycol, etc.

Examples of the polybutadiene polyol include polyols obtained by adding alkylene oxide (for example, ethylene oxide, propylene oxide, etc.) to polybutadiene, and the like. Examples of polyacrylic polyols include polyols obtained by copolymerizing acrylates, vinyl compounds, and the like. Examples of the polyisoprene polyol include polyols obtained by adding alkylene oxide (for example, ethylene oxide, propylene oxide, etc.) to polyisoprene, and the like.

In the polyol component (a), the content of the polyol (a1) is preferably at least 60% by mass, more preferably at least 70% by mass, and is preferably less than 100% by mass, more preferably 99% by mass. Mass% or less.

The short-chain diol (a2) may form a hard segment in the obtained polishing pad. As the short-chain diol (a2), one or more diols having a molecular weight of less than 300 can be used, for example, ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3 - Propylene glycol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol (2,2-Dimethyl-1,3-propanediol), 2-isopropyl-1,4-butanediol, 3-methyl-2,4-pentanediol, 2,4-pentanediol , 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-1,5-pentanediol , 2,4-diethyl-1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2-ethyl -1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9- Nonanediol, aliphatic diols such as 1,10-decanediol, cyclohexanedimethanol (such as 1,4-cyclohexanedimethanol), cyclohexanediol (such as 1,3-cyclohexanediol, 1,4-cyclohexanediol), 2-bis(4-hydroxycyclohexyl)-propane and other alicyclic diols, etc.

Among them, the short-chain diol (a2) is preferably an aliphatic diol, particularly preferably diethylene glycol.

In the polyol component (a), the content of the short-chain diol (a2) is 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15% by mass. Mass % or more, and preferably 50 mass % or less, more preferably 40 mass % or less, still more preferably 30 mass % or less.

In the polyol component (a), the content of the polyol (a1) and the short-chain diol (a2) is preferably at least 80% by mass, more preferably at least 90% by mass, and still more preferably It is 95% by mass or more, and the upper limit is 100% by mass.

The polyol component (a) may contain other polyol (a3) in addition to the polyol (a1) and the short-chain diol (a2). Examples of the other polyhydric alcohol (a3) include: trimethylolethane, trimethylolpropane, hexitols, pentitols, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, tetramethylol Polyhydric alcohols with a molecular weight of less than 300 and three or more hydroxyl groups such as propane.

As the polyisocyanate (b), one or more kinds can be used, for example, polyisocyanates having an alicyclic structure such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate; 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, Aromatic polyisocyanates such as toluene diisocyanate and naphthalene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, xylene diisocyanate, and tetramethylxylene diisocyanate. Among these, in terms of high hardness of the polishing pad and the ability to further increase the polishing rate, aromatic polyisocyanate is preferred, and toluene diisocyanate or diphenylmethane diisocyanate is preferred, and toluene diisocyanate is particularly preferred. diisocyanate.

The equivalent ratio (NCO/OH) of the isocyanate group contained in the polyisocyanate (b) to the hydroxyl group contained in the polyol component (a) is preferably 1.3 or more, more preferably 1.5 or more, and more preferably Preferably it is 6.5 or less, more preferably 4 or less, especially preferably 3 or less. The higher the molar ratio (NCO/OH), the lower the viscosity of the urethane prepolymer (A), the more stable the flow rate is during the production of the polishing pad, the better the mixability, and the easier it is to improve the quality. In addition, the smaller the molar ratio (NCO/OH), the higher the viscosity of the urethane prepolymer (A), and the pot life can be extended.

The urethane prepolymer (A) is a product of the reaction between the polyol component (a) and the polyisocyanate (b) (product of the urethanization reaction). The reaction sequence of the polyol (a1), short-chain diol (a2) and other polyols (a3) used as needed and the polyisocyanate (b) is not particularly limited, and the polyol (a1 ), the short-chain diol (a2) and the other polyols (a3) used as needed are reacted with the polyisocyanate (b) simultaneously, and the polyol (a1) can also be reacted with the poly After the isocyanate (b) is reacted, the obtained product is reacted with a short-chain diol (a2) and other polyol (a3) if necessary.

The isocyanate group equivalent weight of the urethane prepolymer (A) is preferably 200 g/eq. or more, more preferably 250 g/eq. or more, and preferably 800 g/eq. or less, more preferably Preferably less than 600 g/eq.

The isocyanate group equivalent (NCO equivalent) of the urethane prepolymer (A) represents the following value: According to the method specified in JIS-K-7301:2003, the sample is dissolved in dry toluene, and an excess of The di-n-butylamine solution was reacted, and the remaining di-n-butylamine was back-titrated with a hydrochloric acid standard solution to obtain the value.

The viscosity (80°C) of the urethane prepolymer (A) is preferably not more than 2,000 mPa·s, more preferably not more than 1,500 mPa·s, still more preferably not more than 1,200 mPa·s, for example, 300 mPa·s or more, and further may be 400 mPa·s or more. The viscosity (80° C.) of the urethane prepolymer (A) can be measured at a temperature of 80° C. using a B-type viscometer.

The main ingredient (i) may contain other urethane prepolymers other than the urethane prepolymer (A). The content of the urethane prepolymer (A) is preferably 70% by mass or more in the total of the urethane prepolymer (A) and other urethane prepolymers, more preferably 80% by mass or more, more preferably 90% by mass or more, and the upper limit is 100% by mass.

In addition, the main ingredient (i) may further contain polyisocyanate. As the polyisocyanate, those exemplified as the polyisocyanate (b) can be used, particularly preferably aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate and toluene diisocyanate; dicyclohexyl Polyisocyanates having an alicyclic structure, such as methane diisocyanate and isophorone diisocyanate, and the like.

The curing agent (ii) contains a compound having an active hydrogen atom-containing group ([NH] group and/or [OH] group) that reacts with the isocyanate group of the main agent (i). As the compound having a group containing an active hydrogen atom, one or more kinds can be used, for example, aliphatic or alicyclic compounds such as ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, etc. Amine compounds; aromatic amine compounds such as phenylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, polyaminochlorophenylmethane compounds; ethylene glycol, diethylene glycol, propylene glycol , butylene glycol, hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, bisphenol A, alkylene oxide adducts of bisphenol A, polyether polyol, polyester polyol Compounds having two or more hydroxyl groups such as alcohols, polycaprolactone polyols, and polycarbonate polyols; multimers (preferably dimers to tetramers) of the aromatic amine compounds; and these mixture etc.

The mixture is preferably a mixture containing a multimer of the aromatic amine compound, and the content of the multimer in the mixture is preferably 10% by mass or more, more preferably 20% by mass or more, and Preferably it is 80 mass % or less, More preferably, it is 70 mass % or less.

The mixture may further comprise polyols, preferably polyether polyols. The polyol that can be included in the mixture is preferably polyether polyol (especially polyoxytetramethylene glycol), and the number average molecular weight of the polyol is preferably above 300, and is preferably below 3,000, more preferably Preferably it is 2,000 or less, More preferably, it is 1,500 or less.

The urethane resin composition may further include an auxiliary agent (iii).

The auxiliary agent (iii) contained in the urethane resin composition preferably contains a polyol, and the polyol can be combined with the polyol (a1) forming the urethane prepolymer (A) The same can also be different. As the polyhydric alcohol, one kind or two or more kinds can be used, for example, the polyoxyalkylene polyol obtained by the ring-opening polymerization of the cyclic monoether can be used, and the polyoxyalkylene polyol having two or more kinds can also be used. One or two or more compounds containing active hydrogen atom groups are obtained as starting agents.

The content of the polyol in the auxiliary agent (iii) is preferably at least 50% by mass, more preferably at least 70% by mass, further preferably at least 80% by mass, and the upper limit is 100% by mass.

The auxiliary agent (iii) may further include at least one selected from the group consisting of water, a catalyst described later, and a foaming agent described later.

When the urethane resin composition contains the auxiliary agent (iii), the content of the auxiliary agent (iii) may be, for example, 0.1 parts by mass or more with respect to 100 parts by mass of the urethane prepolymer. , and more preferably 1 part by mass or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

In terms of obtaining a polishing pad that has a high polishing rate after polishing and can obtain a polished object with high flatness (less edge rounding), it can be used in combination with the above-mentioned hardener (ii) and the optional The ratio of the total number of moles of isocyanate groups reacted with the auxiliary agent (iii) to the number of moles of isocyanate groups in the main ingredient (i) ([with the hardener (ii) and optionally used The total molar number of the isocyanate group-reacted groups of the auxiliary agent (iii)]/[the molar number of the isocyanate group of the urethane prepolymer (A)]. Hereinafter, referred to as "R value") is preferably 0.7-1.1, more preferably 0.8-1.

With respect to 100 parts by mass of the main ingredient (i), the amount of the hardener (ii) is preferably at least 5 parts by mass, more preferably at least 10 parts by mass, and preferably not more than 50 parts by mass, and more preferably Preferably, it is 30 mass parts or less.

The urethane resin composition used in the present invention contains, as essential components, a main ingredient (i) containing the urethane prepolymer (A) and a curing agent (ii) containing a compound capable of reacting with isocyanate. ingredients, and may also contain other additives. The other additives may be contained in any one of the main ingredient (i), hardener (ii) and optional auxiliary agent (iii) if they do not react with the main ingredient (i) or hardener (ii) or evaporation, etc., may be included in the main ingredient (i) or curing agent (ii), but the additives that react or evaporate, etc., are preferably included in the optional auxiliary agent (iii).

As the other additives, one kind or two or more kinds can be used, for example, water (reactive blowing agent), chemical blowing agent, physical blowing agent, catalyst, foam stabilizer, abrasive grain, filler, pigment , thickener, antioxidant, ultraviolet absorber, surfactant, flame retardant, plasticizer, etc.

Among them, when a polishing pad is obtained by a water foaming method using the above-mentioned urethane resin composition, it is preferable to use water as a reactive foaming agent. When the blowing agent is water, the content of water is preferably 0.01 to 1 part by mass relative to 100 parts by mass of the main ingredient (i). As a blowing agent other than water, a chemical blowing agent or a physical blowing agent can also be used. As chemical blowing agents, there are organic azodicarbonamide (ADCA), N,N'-dinitropentamethylene tetramine (N,N'-dinitropentamethylene tetramine, DPT), 4, 4'-Oxybisbenzenesulphonyl hydrazide (4,4'-oxybisbenzenesulphonyl hydrazide, OBSH) or inorganic bicarbonates, carbonates, combinations of bicarbonates and organic acid salts, etc. As the physical blowing agent, hydrocarbon-based cyclopentane or n-pentane includes chlorofluorocarbon-based HFC-245fa, HFC-365mfc, HCFO-1233zd, HFO-1336mzz, and the like. What is necessary is just to adjust the quantity of a foaming agent suitably so that it may become a target polishing pad density.

As the catalyst, one kind or two or more kinds can be used, for example, N,N-dimethylaminoethyl ether, triethylenediamine, dimethylethanolamine, triethanolamine, N,N,N',N'- Tertiary amine catalysts such as tetramethylhexamethylenediamine and N-methylimidazole; metal catalysts such as dioctyltin dilaurate, etc. Among these, a tertiary amine catalyst is preferable, and N,N-dimethylaminoethyl ether is more preferable in terms of forming stable foam.

When using the catalyst, the content of the catalyst is preferably not less than 0.001 parts by mass and not more than 5 parts by mass relative to 100 parts by mass of the main ingredient (i) so that stable foaming can be formed.

Examples of the foam stabilizer include silicone foam stabilizers, and one or more of them can be used. For example, "Toray Silicone (Toray Silicone) SH-193", "Toray Silicone (Toray Silicone) SH-192" manufactured by Toray Dow Corning Co., Ltd., "Toray Silicone (Toray Silicone) SH-190", etc.

In the case of using the foam stabilizer, the content of the foam stabilizer is preferably 0.001 parts by mass or more with respect to 100 parts by mass of the main ingredient (i) in order to stably form fine bubbles and 5 parts by mass or less.

As a method of producing a polishing pad using the urethane resin composition, for example, the method of mixing the main ingredient (i), the curing agent (ii), and the auxiliary agent (iii) ) are mixed and poured into a mold, foamed and hardened to obtain a foamed molded product, and then the foamed molded product is taken out from the mold and sliced into sheets to manufacture.

Most of the cases where additive (iii) is used is 3,3'-dichloro-4,4'-diaminomethane (MBOCA) for hardener (ii). And the case where water foaming is performed. Regarding the destination of adding water as a reactive foaming agent in water foaming, since the main ingredient (i) reacts with water, it cannot be added to the main ingredient (i). In addition, when added to dissolved MBOCA, it evaporates at 100° C. or higher, so it cannot be added. Therefore, the destination of adding water is preferably the auxiliary agent (iii).

In the case where the auxiliary agent (iii) is included in the urethane resin composition, the content of the auxiliary agent (iii) may be, for example, 0.1 parts by mass or more with respect to 100 parts by mass of the main ingredient (i), and further It may be 1 mass part or more, Preferably it is 10 mass parts or less, More preferably, it is 8 mass parts or less.

As a method of mixing the urethane resin composition, when the auxiliary agent (iii) is used, it is preferable to prepare an auxiliary agent in which polyol, water, catalyst, foam stabilizer, etc. are well mixed in advance. (iii). For example, the method of putting the main ingredient (i), the hardening agent (ii), and the auxiliary agent (iii) into separate tanks of a mixing and pouring machine, and putting the main ingredient (i) ) is heated to preferably 40°C-80°C, the hardener (ii) is heated to preferably 40°C-120°C, the auxiliary agent (iii) is heated to 30°C-70°C, and the The mixing and depositing machine mixes the individual.

In addition, when the auxiliary agent (iii) is not used, other additives only need to be added to the necessary main ingredient (i) or hardener (ii), preferably added to the hardener (ii). A curing agent (ii) in which water, a catalyst, or a foam stabilizer is sufficiently mixed with a compound having an active hydrogen atom-containing group ([NH] group and/or [OH] group) that reacts with an isocyanate group is prepared in advance. For example, the following method can be cited: put the main ingredient (i) and the hardening agent (ii) into different tanks of the mixing and pouring machine, and heat the main ingredient (i) to preferably 40° C. to 80° C., the hardener (ii) is heated to preferably 30° C. to 70° C., and each is mixed using a mixing and pouring machine.

As a method of manufacturing a polishing pad from the urethane resin composition, the following method can be cited: the urethane resin composition is foamed and cured in a mold (preferably in a mold) to obtain a foamed and cured material, followed by post-curing. The obtained foamed cured product may be further molded as needed. Specifically, after mixing the urethane resin composition using the mixing and casting machine, each component is ejected from the mixing and casting machine, and the obtained mixture is injected into a mold previously heated to 40°C to 120°C. In the process, the lid of the mold is covered, and foaming and hardening are performed at a temperature of 50° C. to 130° C. for 10 minutes to 10 hours, thereby obtaining a foamed hardened product. After that, the obtained foamed cured product is taken out, and post-curing is preferably performed at 100° C. to 120° C. for 8 hours to 20 hours. The foamed cured product obtained in this manner is sliced to produce the polishing pad of the present invention.

The thickness of the polishing pad can be appropriately determined according to the application, for example, it is preferably in the range of 0.6 mm to 3 mm.

In addition, as another method of producing a polishing pad using the urethane resin composition, for example, the method of obtaining a main component ( i') (hereinafter, abbreviated as "microbubble-containing main ingredient (i')"), mixing the urethane composition containing the microbubble-containing main ingredient (i') and curing agent (ii) And pour it into the mold, let it harden, and obtain the molded object containing fine bubbles, and then take out the molded object from the mold, and slice it into sheets.

As a method of obtaining the main ingredient (i′) containing fine bubbles from the main ingredient (i), for example, introducing a non-reactive gas such as nitrogen, carbon dioxide gas, helium, or argon into the main ingredient (i), and A method of introducing air bubbles mechanically.

As a method of mixing the urethane composition, for example, putting the main agent (i') containing fine air bubbles and the curing agent (ii) into separate tanks of a mixing and pouring machine, Heat the main agent (i') containing fine air bubbles to preferably 40°C-80°C, heat the hardener (ii) to preferably 40°C-120°C, and use a mixing casting machine Mix each.

Then, each component is ejected from the mixing and pouring machine, and the obtained mixture is injected into a mold preheated to 40° C. to 120° C., and the lid of the mold is covered, for example, at a temperature of 50° C. to 130° C. Foam and harden for 10 minutes to 10 hours to obtain a foamed molded product. After that, the obtained foamed molded product is taken out, and post-curing is preferably performed at 100° C. to 120° C. for 8 hours to 20 hours.

Next, a polishing pad is obtained by slicing the foamed molded product into sheets with an appropriate thickness. The thickness of the polished pad after slicing can be appropriately determined according to the application, and is, for example, in the range of 0.6 mm to 3 mm.

In addition, as another method of producing a polishing pad using the above-mentioned urethane composition, for example, the following method can be cited: when the main ingredient (i) and the hardener (ii) are mixed using a mixing and pouring machine, the mixed The machine part introduces and mixes non-reactive gas, injects the mechanical froth mixture into the mold, makes it harden to obtain a foamed product, and then takes the foamed product out of the mold, and Slice into flakes.

Furthermore, as another method of producing a polishing pad using the urethane resin composition, for example, the method of adding a 20 μm to 120 μm diameter Hollow plastic spheres (microballoons). Mix the two solutions of the main agent and the hardener and harden them to obtain a molded product containing hollow plastic spheres, which are then sliced into flakes.

The polishing pad of the present invention has a high polishing rate, and can obtain high flatness (less edge rounding), and is suitable for optical lenses, glass substrates for liquid crystal displays (LCD), glass substrates for hard disks (HDD), and glass for recording devices. It is useful for polishing processes that require high polishing rates and high levels of flatness (edge rounding), such as disks, optical lenses, silicon wafers, and semiconductor devices. In particular, it is useful for polishing a material to be polished with a Vickers hardness of 1500 or less, specifically, it is useful for polishing silicon wafers or glass.

Vickers hardness is one of the indicators of indentation hardness, which is judged by the area of the indentation formed when a rigid body (indenter) made of diamond is pressed into the test object. As a test method, there is JIS-Z-2244. The rough Vickers hardness of each polished is roughly as follows. Silicon carbide (SiC): 2300-2500, sapphire: 2300, silicon: 1050, quartz glass: 950, various glasses: 500-700.

As a polishing method using the polishing pad of the present invention, for example, in the case of silicon wafer polishing, the following methods (the CMP polishing method utilizing free abrasive grains) are enumerated: dripping slurry (weakly alkaline colloid) on the polishing pad Silicon oxide aqueous solution), and the object to be polished is pressure-bonded on the pad compatible with the slurry, and the platen with the pad attached is operated (rotated) to perform grinding. Example

Hereinafter, examples will be given to describe the present invention more specifically.

In the examples, the number average molecular weight of the polyol (a1) was measured by colloid permeation chromatography (GPC method). Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation) Column: The following columns (all manufactured by Tosoh Corporation) were connected in series and used. "TSKgel G5000" (7.8 mmI.D. × 30 cm) × 1 "TSKgel G4000" (7.8 mmI.D. × 30 cm) × 1 "TSKgel G3000" (7.8 mmI.D. × 30 cm) × 1 Root “TSKgel G2000” (7.8 mmI.D.×30 cm)×1 detector: RI (differential refractometer) Column temperature: 40°C Eluent: tetrahydrofuran (THF) Flow rate: 1.0 mL/min Injection volume : 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: A calibration curve was prepared using the following standard polystyrene. (Standard polystyrene) "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation Polystyrene A-2500" "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation Standard Polystyrene F-2" Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-4" Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-10" Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-288" Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-550"

(Synthesis Example 1 to Synthesis Example 4, Comparative Synthesis Example 1 to Comparative Synthesis Example 3, Comparative Synthesis Example 5 to Comparative Synthesis Example 9: Urethane Prepolymer (A1) to Urethane Prepolymer (A4) , Urethane Prepolymer (A'1) ~ Urethane Prepolymer (A'3), Urethane Prepolymer (A'5) ~ Urethane Prepolymer (A' 9) Synthesis) The polyisocyanate (b) shown in Table 1 was charged into a 5-liter four-necked round-bottomed flask equipped with a nitrogen gas inlet tube, a cooling condenser, a thermometer, and a stirrer, and stirring was started. Next, the polyol (a1) shown in Table 1 was charged and mixed, and reacted at 80° C. for 3 hours under a nitrogen atmosphere. Next, while paying attention to heat generation, the short-chain diol (a2) shown in Table 1 was reacted at 80° C. for 3 hours to obtain an isocyanate group-terminated urethane prepolymer (A1) having an NCO equivalent weight shown in Table 1. ~ Isocyanate-terminated urethane prepolymer (A4), Isocyanate-terminated urethane prepolymer (A'1) ~ Isocyanate-terminated urethane prepolymer (A'3), Isocyanate-terminated Urethane prepolymer (A'5) to isocyanate group-terminated urethane prepolymer (A'9).

(Synthesis Example 5) The polyisocyanate (b) shown in Table 1 was charged into a 5-liter four-necked round-bottomed flask equipped with a nitrogen gas introduction tube, a cooling condenser, a thermometer, and a stirrer, and stirring was started. Next, the polyol (a1) shown in Table 1 was charged and mixed, and reacted at 80° C. for 3 hours under a nitrogen atmosphere. Next, while paying attention to heat generation, the short-chain diol (a2) shown in Table 1 was reacted at 80° C. for 3 hours to obtain an isocyanate group-terminated urethane prepolymer having an NCO equivalent of 371. Next, in order to remove free TDI (unreacted TDI) from the obtained isocyanate group-terminated urethane prepolymer, thin-film distillation treatment was further performed to obtain an isocyanate group-terminated urethane prepolymer with NCO equivalent: 435 (A5).

(Comparative synthesis example 4) In the same manner as in synthesis example 5, an isocyanate group-terminated urethane prepolymer having an NCO equivalent of 380 was obtained. Next, in order to remove free TDI (unreacted TDI) from the obtained isocyanate group-terminated urethane prepolymer, thin-film distillation treatment was further performed to obtain an isocyanate group-terminated urethane prepolymer with NCO equivalent: 438 (A'4).

[Table 1]

[Table 2]

In Tables 1 to 2, polytetramethylene glycol 1 (also called "PTMG1000") means polytetramethylene glycol (number average molecular weight 1,000), and polytetramethylene glycol 2 (also called "PTMG1000") "PTMG2000") means polytetramethylene glycol (number average molecular weight 2,000), polytetramethylene glycol 3 (also known as "PTMG650") means polytetramethylene glycol (number average molecular weight 650), polyoxypropylene polyol 1 ("EL430" manufactured by Asahi Glass Urethane) means polyoxypropylene polyol (the number of hydroxyl groups is 3, and the number average molecular weight is 430), polyoxypropylene polyol 2 (Asahi Glass Urethane "EL410NE" manufactured by Asahi Glass Urethane) means polyoxypropylene polyol (4 hydroxyl groups, number average molecular weight 410), polyoxypropylene polyol 3 ("EL3030" manufactured by Asahi Glass Urethane) means polyoxypropylene polyol Alcohol (3 hydroxyl groups, number average molecular weight 3,000), polyoxypropylene polyol 4 ("EL1030" manufactured by Asahi Glass Urethane) means polyoxypropylene polyol (3 hydroxyl groups, number average molecular weight 1,000) , polyoxybutylene glycol 1 (also known as "PBG2000") means polyoxybutylene glycol (number average molecular weight 2,000), polybutylene adipate 1 (also known as "BGAA2000") means containing 1,4 -Polyester polyol of butanediol and adipic acid (the number of hydroxyl groups is 2, the number average molecular weight is 2,000), polybutylene adipate 2 (also called "BGAA1000") means that it contains 1,4-butanediol Polyester polyol of alcohol and adipic acid (hydroxyl number 2, number average molecular weight 1,000), polyisocyanate (T80) means TDI (2,4/2,6 isomer ratio 80/20), poly Isocyanate (T100) means 2,4-TDI.

(Example 1-Example 5, Comparative Example 1-Comparative Example 9) The isocyanate group-terminated urethane prepolymer obtained in Synthesis Example 1-Synthesis Example 5, Comparative Synthesis Example 1-Comparative Synthesis Example 9 ( A1) ~ Isocyanate-terminated urethane prepolymer (A5), Isocyanate-terminated urethane prepolymer (A'1) ~ Isocyanate-terminated urethane prepolymer (A'9) Temperature control is 80°C, and is set as the main ingredient (i). Next, the curing agent (MBOCA) was melted at 120° C. and the temperature was adjusted to obtain the curing agent (ii). Furthermore, the prepared liquid shown in Table 3 was temperature-regulated at 35 degreeC, and it was set as auxiliary agent (iii). Next, put the main ingredient (i) in the number of parts shown in Table 4 into the reaction container and adjust the temperature to 80°C, then put in the liquid C at 35°C in the number of parts shown in Table 3 to Table 4, and immediately 120 degreeC hardening|curing agent (ii) of the part shown in Table 4 was injected|thrown-in, and it stirred for 20 seconds with the high-speed mixer immediately. Flow 6000 parts of the mixed main agent (i)/hardener (ii)/auxiliary (iii) into a 500 mm×500 mm×40 mm mold with a temperature of 60°C, and cover the mold Covered and kept at 60° C. for 1 hour, the ingot-shaped expanded molded product was taken out. Furthermore, post-curing was performed for 16 hours at 100 degreeC with respect to the obtained ingot shape foaming molding. Cut the obtained ingot-shaped foam molded product into a thickness of 1.5 mm with a slicer to obtain sheet-shaped polishing pads (P1) to polishing pads (P5), polishing pads (P'1) to polishing pads (P'8) . The evaluation results of density, hardness, tan δ peak temperature at 120° C. to 200° C., tan δ value, polishing rate, and edge rounding in the dynamic viscoelasticity measurement of the obtained polishing pad are shown in Table 5.

(Examples 6 to 8, Comparative Examples 10 to 11) The temperature of the isocyanate group-terminated urethane prepolymer shown in Table 4 was adjusted to 80° C., and it was used as the main ingredient (i). The prepared liquids (B1, B2) shown in Table 3 were temperature-regulated at 40° C., and used as the curing agent (ii). Next, put the main ingredient (i) in the number of parts shown in Table 4 into the reaction container and adjust the temperature to 80°C, then put the prepared solution (B1, B2) in the number of parts shown in Table 4 at 40°C, Immediately blend for 20 seconds using a high speed mixer. Flow 6000 parts of the mixed main agent (i)/hardening agent (ii) into a 500 mm×500 mm×40 mm mold whose temperature is adjusted to 60°C, cover the mold, and set the temperature at 60°C After holding for 1 hour, the ingot-shaped foamed molded product was taken out. Furthermore, post-curing was performed for 16 hours at 80 degreeC about the obtained ingot shape foaming molding.

The obtained ingot-shaped foam molded product was cut into a thickness of 1.5 mm using a slicer to obtain sheet-shaped polishing pads (P6) to polishing pads (P8), polishing pads (P'9) to polishing pads (P'10) . The evaluation results of density, hardness, tan δ peak temperature at 120° C. to 200° C., tan δ value, polishing rate, and edge rounding in the dynamic viscoelasticity measurement of the obtained polishing pad are shown in Table 5.

The measurement methods (evaluation methods) of the tan δ peak temperature, tan δ value, polishing rate, and edge rounding are as follows.

[Measuring method of tan δ peak temperature and tan δ value] Using a polishing pad with a thickness of 1.5 mm, the tan δ peak temperature (also called "loss coefficient peak temperature") was measured by dynamic viscoelastic analysis in accordance with JIS K 7244 in the following procedure (°C), evaluating the viscoelasticity of a 1.5 mm thick abrasive pad. Using a viscoelastic spectrometer (model: DMS6100, manufactured by SII Nano Technology Co., Ltd.), under the conditions of temperature range -100°C to 200°C, heating rate 5°C/min, and frequency 1 Hz, the The storage elastic coefficient (E') and the loss elastic coefficient (E'') of the polishing pad are measured in the tensile mode. When E''/E' is tan δ, the temperature at which tan δ becomes the maximum value in the range of 120°C to 200°C is defined as "tan δ peak temperature (°C)", and E' at the tan δ peak temperature is '/E' is set to the tan δ value. Measurement conditions: (sample size) 5 mm×60 mm×1.5 mm (span) 20 mm (strain) 0.05%

[Evaluation method of polishing rate] The polishing pads obtained in Examples and Comparative Examples were attached to one side of the double-sided tape, and the platen of the grinder was attached to the other side of the double-sided tape, and the following method was used: Devices, conditions, and calculation formulas are used to determine the grinding rate. Grinding machine: FAM 18 GPAW (Platen diameter = 457 m, water-cooled type manufactured by Speed Fam Co., Ltd.) Grinding conditions: (Pad pretreatment) Dressing with a diamond dresser (#100) (pad flattening and dressing sharp) until the lines traced vertically and horizontally with a red pencil at 2 cm intervals on the surface of the pad disappear. Water supply: 200 ml/min (grinding object) 4-inch monocrystalline silicon wafer thickness: 540 μm (silicon wafer support method) ceramic block / microporous velvet pad (suede pad) (water adsorption) silicon wafer (grinder cooling water) 20°C (slurry) Colloidal silicon oxide solution Diluted 20 times "N6501" manufactured by Nitta Haas Co., Ltd. (slurry flow rate) 100 ml/min (circulation type) (platen rotation speed) 50 rpm ( Pulling rotary type) (polishing pressure) 30 kPa (polishing time) 20 minutes (polishing rate) Calculated from the weight difference of the polyurethane polishing pad before and after polishing. That is, grinding rate (μm/min) = (weight of silicon wafer before grinding (g) - weight of silicon wafer after grinding (g)) × 10000 / (density of single crystal silicon (g/cm ³ ) × silicon Wafer area (cm ² ) × grinding time (min)) Density of monocrystalline silicon = 2.329 g/cm ³ Area of silicon wafer = 20.4 cm ²

[Evaluation method for edge rounding] After the above-mentioned polishing rate evaluation, redressing treatment was performed for 1 hour with a diamond dresser (#100). Thereafter, instead of a new object to be polished, polishing was performed under the following polishing conditions. After grinding, the height of the object to be ground was measured by a spectroscopic interference laser displacement meter. Grinding conditions: (grinding object) 4-inch single-crystal silicon wafer thickness: 540 μm (silicon wafer support method) ceramic block/wax/silicon wafer (grinding machine cooling water) 20°C (slurry) colloidal silicon oxide solution Nidahas "N6501" manufactured by (Nitta Haas) Co., Ltd. diluted 20 times (slurry flow rate) 100 ml/min (circulation type) (platen rotation speed) 50 rpm (pulling rotation type) (grinding pressure) 30 kPa (grinding time) 60-minute laser displacement meter conditions: (Machine) SI-F10/KS-1100 (manufactured by Keyence Co., Ltd.) (Measuring points) 101×101=10201 points (measure until it is attached to the ceramic block) (Analysis software) KS Analyzer (Keyence Co., Ltd.) (Edge rounding evaluation site) Line segment (diameter) passing through the center of the silicon wafer (Edge rounding evaluation) Passing maximum height - 2 mm from the left end The height of the site is evaluated.

[table 3]

In Table 3, polyoxypropylene polyol 3 ("EL3030" manufactured by Asahi Glass Urethanes) represents polyoxypropylene polyol (the number of hydroxyl groups is 3, and the number average molecular weight is 3,000), and aromatic aminochlorophenylmethane mixture represents Contains a mixture of 3,3'-dichloro-4,4-diaminophenylmethane (MBOCA) and its polymers and polyether polyols (active hydrogen equivalent: 189), TOYOCAT ET is manufactured by Tosoh Co., Ltd. Co., Ltd., which means a mixture of bis(dimethylaminoethyl) ether (70%) and dipropylene glycol (30%). SH-193 is manufactured by Toray Dow Corning Co., Ltd., which means silicone whole foaming agent.

[Table 4]

In Table 4, MBOCA represents 3,3'-dichloro-4,4-diaminophenylmethane.

實施例1～實施例8的研磨墊為本發明的研磨墊，具有高研磨速率，且可獲得高平坦性優異（邊緣倒圓少）的被研磨物。 比較例1～比較例3、比較例5、比較例7的tanδ值小，比較例4、比較例7、比較例9、比較例10的tanδ峰值溫度低，比較例6的多元醇成分（a）中所含的聚四亞甲基二醇的含有率低，比較例8無tanδ峰值溫度，無法兼顧高研磨速率及高平坦性。[table 5]

The polishing pads of Examples 1 to 8 are the polishing pads of the present invention, have a high polishing rate, and can obtain an object to be polished with excellent flatness (less edge rounding). The tan δ values of Comparative Examples 1 to 3, Comparative Example 5, and Comparative Example 7 were small, and the tan δ peak temperatures of Comparative Example 4, Comparative Example 7, Comparative Example 9, and Comparative Example 10 were low, and the polyol component of Comparative Example 6 (a ) The content of polytetramethylene glycol contained in ) is low, and Comparative Example 8 has no tanδ peak temperature, and high polishing rate and high flatness cannot be achieved at the same time.

In addition, as shown in FIG. 1 in the cross section of the polishing pad of the present invention, fuzzing occurred, and the presence of fine domains having specific viscoelasticity was confirmed. On the other hand, the cross section of the polishing pad of the comparative example was smooth as shown in FIG. 2 . Fig. 3 is a dynamic viscoelasticity measurement chart of the polishing pad of Example 3. FIG. 4 is a distribution diagram of heights measured by a spectroscopic interference laser displacement meter on the surface of a silicon wafer polished by the polishing pad of Example 3. FIG. 5 is a dynamic viscoelasticity measurement graph of the polishing pad of Comparative Example 7. FIG. 6 is a distribution diagram of heights measured by a spectroscopic interference laser displacement meter on the surface of a silicon wafer polished by the polishing pad of Comparative Example 7. FIG.

none

FIG. 1 is a scanning electron microscope (SEM) image of a cross section (sliced plane) of the polishing pad of Example 1. FIG. FIG. 2 is a scanning electron microscope (SEM) image of a cross section (slice plane) of the polishing pad of Comparative Example 1. FIG. Fig. 3 is a dynamic viscoelasticity measurement chart of the polishing pad of Example 3. FIG. 4 is a distribution diagram of heights measured by a spectroscopic interference laser displacement meter on the surface of a silicon wafer polished by the polishing pad of Example 3. FIG. 5 is a dynamic viscoelasticity measurement graph of the polishing pad of Comparative Example 7. FIG. 6 is a distribution diagram of heights measured by a spectroscopic interference laser displacement meter on the surface of a silicon wafer polished by the polishing pad of Comparative Example 7. FIG.

Claims (6)

A polishing pad, characterized in that: it is a hardened product of a urethane resin composition containing a main agent (i) comprising a urethane prepolymer (A) and a hardening agent (ii), wherein the The urethane prepolymer (A) is obtained by reacting the polyol component (a) containing the polyol (a1) with a molecular weight of 300 or more and the short-chain diol (a2) with a molecular weight of less than 300, and polyisocyanate (b) and has an isocyanate group at the terminal, the polyol component (a) contains polytetramethylene glycol at a content rate of 40% by mass or more and 85% by mass or less, and the short-chain diol (a2) The content rate of the polyol component (a) is 1% by mass or more, and the hardened product has tan δ in the range of 120°C to 200°C in the dynamic viscoelasticity measurement with a measurement frequency of 1 Hz. , and the peak value of tanδ in the range of 120° C. to 200° C. is 0.18 or more. The polishing pad as described in claim 1 of the patent application, wherein the short-chain diol (a2) with a molecular weight of less than 300 is diethylene glycol. The polishing pad as described in item 1 or item 2 of the scope of the patent application, wherein the polyol (a1) is polytetramethylene glycol, and in the polyol component (a), polytetramethylene glycol The content rate of diol is 60 mass % or more. The polishing pad according to claim 1 or claim 2, wherein the polyol (a1) has a number average molecular weight of 1,100 or more. The polishing pad as described in item 1 or item 2 of the scope of patent application, wherein The polyisocyanate (b) is an aromatic polyisocyanate. The polishing pad according to claim 1 or claim 2, wherein the hardener (ii) is an aromatic amine compound.

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