KR20130043060A - Urethane resin composition for polishing pad and polyurethane polishing pad - Google Patents

Abstract

PURPOSE: A urethane resin composition for polishing pads is provided to provide to provide a polishing pad with excellent polishing rate, scratch resistance, and flatness and to have excellent durability. CONSTITUTION: A urethane resin composition for polishing pads comprises a base material which contains a urethane prepolymer which contains an isocyanate group, a hardening agent containing a functional group reactable with the isocyanate group and additionally comprises fumed silica. The use amount of the fumed silica is 0.5-2 parts by weight based on 100.0 parts by weight of the urethane prepolymer. The fumed silica is hydrophobic fumed silica. A polishing pad is obtained by using the urethane resin composition for polishing pads.

Description

Urethane resin composition for polyurethane pad and polyurethane polishing pad TECHNICAL FIELD

The present invention relates to a urethane resin composition for thermosetting urethane (TSU) type polishing pads used in glass polishing fields such as glass substrates, silicon wafers, semiconductor devices and the like, and polyurethane polishing pads obtained using the same.

Glass substrates for liquid crystal displays (LCDs), glass substrates for hard disks (HDDs), glass disks for recording devices, optical lenses, silicon wafers, semiconductor devices and the like require high surface flatness and in-plane uniformity.

In semiconductor devices, as the degree of integration of semiconductor circuits rapidly increases, miniaturization and multilayer wiring for the purpose of high density proceed, and the technology of further flattening the processed surface becomes important. On the other hand, in the glass substrate for liquid crystal displays, with the enlargement of a liquid crystal display, the higher level flatness of a process surface is calculated | required. As the demand for flatness has been advanced, demanded performances such as polishing accuracy and polishing efficiency in polishing have been increasing.

In the manufacturing process of a semiconductor device and an optical device, the chemical mechanical polishing method, what is called CMP (Chemical Mechanical Polishing), is employ | adopted widely as a grinding | polishing method which can form the surface which has the outstanding flatness.

In the CMP method, generally, a so-called glass abrasive grain method of supplying and polishing a slurry (polishing liquid) in which abrasive grains (polishing particles) are dispersed in an alkaline solution or an acid solution during polishing is employed. have. That is, the to-be-processed object (the processed surface) is planarized by the mechanical action by the abrasive grain in a slurry, and the chemical action by alkaline solution or an acid solution. With the advancement of the flatness required for the processing surface, the polishing performance such as polishing accuracy and polishing efficiency required for the CMP method, specifically, high polishing rate, non-scratchability and high flatness are required. It is rising. As a polishing pad of the CMP glass abrasive grain method, the technique which aims at stabilizing polishing performance by optimizing the grade of abrasion, for example is reported (for example, refer patent document 1). On the other hand, from a waste liquid process and a cost problem, the fixed abrasive type polishing pad is also proposed without using a glass abrasive grain (for example, refer patent document 2).

However, the polishing pad of the glass abrasive grain method described above has a problem in that the urethane resin is slightly soft and the quality of the maturation period is several months, since the R value is set low to 0.7 to 0.9 to control the amount of wear. have. In addition, the fixed abrasive abrasive pad, which is the non-glass abrasive grain method, has a problem that scratches are likely to occur.

As mentioned above, although an industrial polishing pad strongly demands high polishing rate, non-scratchability, and flatness which are constantly required for precision polishing, it has not been found yet.

Japanese Patent Application Laid-Open No. 2010-76075 Japanese Patent Application Laid-Open No. 2011-142249

The problem to be solved by the present invention is to provide a CMP polishing pad excellent in polishing characteristics (high polishing rate, non-scratchability, flatness).

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in view of the kind of additive, progressing research in order to solve the said subject.

As a result, by adding fumed silica, it discovered that the polishing pad which satisfy | fills the said subject was obtained, and came to complete this invention.

That is, this invention is a urethane resin composition for polishing pads which contains the main body containing the urethane prepolymer (A) which has an isocyanate group, and the hardening | curing agent containing the compound (B) which has a functional group which reacts with an isocyanate group, It is to provide a urethane resin composition for a polishing pad and a polyurethane polishing pad, further comprising fumed silica (C).

The urethane resin composition for a polishing pad of the present invention can provide a polishing pad excellent in high polishing rate, non-scratchability and flatness. Moreover, even if it is used over time, polishing property is hard to fall and it is excellent in durability.

Therefore, the polyurethane polishing pad obtained using the urethane resin composition for polishing pads of the present invention is a glass substrate for liquid crystal display (LCD), a glass substrate for hard disk (HDD), a glass disk for recording device, an optical lens, silicon Useful for high-precision polishing, such as wafers, semiconductor devices, sapphire substrates for LEDs, silicon carbide substrates, gallium arsenide substrates, optical substrates, magnetic substrates, etc., which require high surface flatness and in-plane uniformity. Do.

The urethane resin composition for a polishing pad of the present invention is a compound containing a urethane prepolymer (A) having an isocyanate group (hereinafter abbreviated as "urethane prepolymer (A)") and a functional group reacting with an isocyanate group (B). (Hereinafter, abbreviated as "compound (B)") and a fumed silica (C) are included.

First, the urethane prepolymer (A) will be described. The said urethane prepolymer is obtained by making a polyisocyanate (a1) and a polyol (a2) react in accordance with a conventionally well-known method.

As said polyisocyanate (a1), for example, a mixture of tolylene diisocyanate (TDI-100; toluene diisocyanate of 2,4-body, TDI-80; 2,4- and toluene diisocyanate) 2,4-body / 2,6-body = 80/20 mass ratio), tolidine diisocyanate (TODI), diphenylmethane diisocyanate (abbreviated MDI; its 4,4'-form, 2,4'-form) , Or 2,2'-form or mixtures thereof), polymethylene polyphenylpolyisocyanate, carbodiimide-ized diphenylmethane polyisocyanate, xylylene diisocyanate (XDI), 1,5-naphthalenedi isocyanate (NDI), tetra Aromatic diisocyanates such as methyl xylene diisocyanate; Or alicyclic diisocyanates such as isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI); And aliphatic diisocyanates such as hexamethylene diisocyanate, dimer acid diisocyanate and norbornene diisocyanate. Among these, tolylene diisocyanate (TDI), tolidine diisocyanate (TODI), and hydrogenated diphenylmethane diisocyanate (hydrogenated MDI) can improve polishing characteristics more easily, and it is easier to control the reactivity at work. Preferred at

As the polyol (a2), for example, at least one polyol selected from the group consisting of low molecular weight polyols, polyester polyols, polycarbonate polyols, polyether polyols, polyester polyols, polybutadiene polyols and silicone polyols can be used. . Although the kind and quantity of these polyols are suitably selected according to the use used, it is preferable to use a polyether polyol from a viewpoint of hydrolysis resistance, and it is especially preferable to use polytetramethylene ether glycol. .

Examples of the low molecular weight polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, and 2-butyl-2-ethyl-1,3-propane Diol, 1,3-butanediol, 1,4-butanediol, neopentylglycol (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, 1,10-decanediol Aliphatic diols; Cyclohexanedimethanol (eg 1,4-cyclohexanedimethanol), cyclohexanediol (eg 1,3-cyclohexanediol, 1,4-cyclohexanediol), 2-bis (4-hydroxy Alicyclic diols such as cyclohexyl) -propane; Trivalent or more polyols, such as trimethylol ethane, trimethylol propane, hexitols, pentitols, glycerin, polyglycerol, pentaerythritol, dipentaerythritol, tetramethylolpropane, and the like.

As said polyester polyol, esterified products of polyols, such as said low molecular weight polyol, and ester-forming derivatives (ester, anhydride, halide, etc.) of polyhydric carboxylic acid, polyhydric carboxylic acid, lactone, hydroxycarboxylic acid, etc. are mentioned, for example. . Examples of the polyhydric carboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecane diacid, 2-methyl succinic acid, and 2-methylamic acid. Dipic acid, 3-methyladipic acid, 3-methylpentane diacid, 2-methyloctane diacid, 3,8-dimethyldecane diacid, 3,7-dimethyldecane diacid, aliphatic dicarboxylic acid (e.g. hydrogenated Dimer acid, dimer acid, etc.), aromatic dicarboxylic acid (e.g., phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc.), alicyclic dicarboxylic acid (e.g., cyclohexanedicarboxylic acid, etc.), tricarboxylic acid (e.g., tricarboxylic acid) Methalic acid, trimesic acid, trimer of castor oil fatty acid, etc.), tetracarboxylic acid (for example, pyromellitic acid), etc. are mentioned. As ester-forming derivatives of the polyhydric carboxylic acid, for example, acid anhydride, halide (chloride, bromide, etc.), ester (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, amyl) Lower aliphatic esters such as esters); and the like. Examples of the lactone include γ-caprolactone, δ-caprolactone, ε-caprolactone, dimethyl-ε-caprolactone, δ-valerolactone, γ-valerolactone, γ-butyrolactone, and the like. have. The hydroxycarboxylic acid may be, for example, a hydroxycarboxylic acid having a structure in which the lactone is ring-opened.

As said polyether polyol, an ethylene oxide addition product, a propylene oxide addition product, polytetramethylene glycol, the oxide addition product of the said low molecular polyol is mentioned, for example. As said ethylene oxide addition product, diethylene glycol, triethylene glycol, etc. are mentioned, for example, As said propylene oxide addition product, dipropylene glycol, tripropylene glycol, etc. are mentioned, for example. As an oxide adduct of the said low molecular polyol, an ethylene oxide adduct, a propylene oxide adduct, ethylene oxide, a propylene oxide adduct, etc. are mentioned, for example.

As said polycarbonate polyol, what is obtained by making carbonate ester and / or phosgene react with the polyol mentioned later, for example can be used.

As said carbonate ester, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, etc. are mentioned, for example.

Moreover, as a polyol which can react with the said carbonate ester and phosgene, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol , Tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol , 2-methyl-1,3-propanediol, neopentylglycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3- Hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin, bisphenol A, bisphenol F, 4,4'-ratio Relatively low molecular weight dihydroxy compounds such as phenol, polyethylene glycol, polypropylene glycol, Polyether polyols, such as polytetramethylene glycol, Polyester polyols, such as polyhexamethylene adipate, polyhexamethylene succinate, and polycaprolactone, etc. are mentioned.

As a number average molecular weight of the said polyol (a2) except a low molecular weight polyol, it is preferable that it is the range of 500-5,000 from a viewpoint of the outstanding strength elongation and viscoelasticity of a urethane resin, Especially the range of 500-2,000 is desirable. In addition, the number average molecular weight of the said polyol (a2) shows the number average molecular weight with which a hydroxyl value is calculated | required from an acid value.

Number average molecular weight = (56,100 × f) / (hydroxyl value + acid value)

In addition, f: functional group

Although the conventionally well-known method can be used for the method of manufacturing the said prepolymer (A), reaction can be accelerated | stimulated using a tertiary amine catalyst, an organometallic catalyst, etc. as needed at the time of manufacture.

As an isocyanate group equivalent (NCO equivalent) of the said prepolymer (A), it is preferable that it is the range of 200-750 g / eq., And the range of 250-700 g / eq. Is more preferable.

Next, the said hardening | curing agent is demonstrated. The said hardening | curing agent may contain water (D), a catalyst (E), a foam stabilizer (F), etc. which are foaming agents with the compound (B) which is an essential component.

The said compound (B) should just have a functional group which has favorable reactivity with respect to the compound which has an isocyanate group, For example, an amine compound and polyols are mentioned.

Examples of the amine compound include ethylenediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'- Dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, 1,2-propanediamine, diethylenetriamine, triethylenetetramine, 3,3'-dichloro-4,4'- Amine compounds such as diaminodiphenylmethane, polyaminochlorophenylmethane compound and Pandex E-50 (trademark: DIC Corporation, polyaminochlorophenylmethane compound); Hydrazines, such as hydrazine and sanhydrazide, are mentioned.

Examples of the polyols include polyether polyols such as polytetramethylene glycol and polypropylene glycol, polyester polyols, polycarbonate polyols, and low molecular weight polyols.

The said compound (B) may be used independently or may use 2 or more types together. That is, you may use what the amine compound melt | dissolved in polyols. When using 2 or more types of said compounds (B) together, it is good also as a two-component urethane resin composition of the said main body and the hardening | curing agent containing 2 or more types of compounds (B), and hardening | curing agent 2 or more (for example, a compound) You may divide (B) and said (B) into another compound (B)).

As said compound (B), among the above-mentioned, a polyamino chlorophenylmethane compound is preferable from a viewpoint of hydrothermal resistance and abrasion resistance, and 3,3'- dichloro-4,4'- diamino diphenylmethane is Particularly preferred.

As the usage-amount of the said compound (B), Preferably it is the range of 15-80 mass parts with respect to 100 mass parts of said prepolymers (A), More preferably, it is the range of 20-60 mass parts.

In addition, the said water (D) is mix | blended in order to play the role of a foaming agent in a water-foaming method. As the usage-amount of water, it is the range of 0.05-3 mass parts with respect to 100 mass parts of said compounds (B), More preferably, it is the range of 0.5-2 mass parts.

As the addition method of the said water (D) at the time of mixing a main body and a hardening | curing agent, it is a compound (B), water (D), and a catalyst (E), a foaming agent (F), etc. as needed previously, as a hardening | curing agent, for example. The additive is added and mixed, and then the first component (A) and the second component ((B) + (D) + other additives) are mixed, foamed and cured, or a compound (B) In the case of melting point of 100 ° C. or higher, water (D) and other additives such as catalyst (E) and foam stabilizer (F) are added and mixed with other compounds (B) having a melting point of 100 ° C. or lower, Then, the method of mixing, foaming and hardening a 1st component (A), a 2nd component (B), and a 3rd component ((B) + (D) + other additive) is mentioned.

Examples of the catalyst (E) include triethylenediamine, N, N, N ', N'-tetramethylhexanediamine, N, N, N', N'-tetramethylpropanediamine, N, N, N ' , N '', N ''-pentamethyldiethylenetriamine, N, N ', N'-trimethylaminoethylpiperazine, N, N-dimethylcyclohexylamine, N, N, N', N'-tetra Methylethylenediamine, bis (3-dimethylaminopropyl) -N, N-dimethylpropanediamine, N, N-dicyclohexylmethylamine, bis (dimethylaminoethyl) ether, N, N ', N' '-tris ( 3-dimethylaminopropyl) hexahydro-S-triazine, N, N-dimethylbenzylamine, N, N-dimethylaminoethoxyethoxyethanol, N, N-dimethylaminohexanol, N, N-dimethylamino Methoxyethanol, N, N, N'-trimethylaminoethylethanolamine, N, N, N'-trimethyl-2-hydroxyethylpropylenediamine, 1-methylimidazole, 1-isobutyl-2-methylimida Amine catalysts such as sol, 1,2-dimethylimidazole, dimethylethanolamine and triethanolamine; Metal catalysts such as dibutyltin dilaurate, dioctyl tin dilaurate, tin octylate 2-ethylhexanoic acid, potassium octylate, dibutyltin laurylmelcaptide and bismuth tris (2-ethylhexanoate); Can be mentioned. Among these, tertiary amines with strong saturation characteristics are preferred.

The amount of the catalyst (E) used is preferably in the range of 0.01 to 1.0 parts by mass, and more preferably in the range of 0.05 to 0.3 parts by mass relative to 100 parts by mass of the compound (B). If the compounding quantity of the said catalyst is this range, the foaming state of a polishing pad will be more stable.

As said foam stabilizer (F), what is necessary is just to be able to form fine bubbles stably, and silicone type surfactant is used preferably. As said foam stabilizer (F), for example, "SZ-1919", "SH-192", "SH-190", "SZ-580", "SRX-280A", "SZ-1959", "SZ- 1328E "," SF-2937F "," SF-2938F "," SZ-1671 "," SH-193 "," SZ-1923 "(above, made by Toray Dow Corning Co., Ltd.), etc. are available as a commercial item. Can be.

Next, the said fumed silica (C) is demonstrated. Although the said fumed silica (C) may be mix | blended with either the said main material or the said hardening | curing agent, since a compounding quantity can be put into many, it is more preferable to mix | blend with the said main material with a large compounding ratio.

The fumed silica (C) may be any of non-modified fumed silica (hydrophilic silica) and hydrophobic fumed silica in which the surface of particles of fumed silica is hydrophobically modified by various surface treatment agents. Among these, it is preferable to use hydrophobic fumed silica from the point which can improve a grinding | polishing characteristic further.

The said fumed silica is obtained by the dry method, and specifically, is silicon dioxide which vaporized silicon tetrachloride and hydrolyzed in high temperature salt. However, in the manufacturing process, what aggregated these is formed.

On the surface of the agglomerated silicon dioxide, siloxane and silanol groups exist and exhibit hydrophilicity. On the other hand, hydrophobicity is provided by making a surface treating agent react with this silanol group. In addition, in this invention, "hydrophobic" means having reacted 15% or more with the siloxane and silanol which exist in the surface of the said agglomerated silicon dioxide, and the said surface treating agent.

Examples of the surface treating agent include silane compounds such as dimethyldichlorosilane, dimethyl silicone oil, hexamethyldisilazane, octylsilane, hexadecylsilane, aminosilane, methacrylsilane, octamethylcyclotetrasiloxane, and polydimethylsiloxane. Can be mentioned.

Moreover, as a specific surface area by the BET method of the said fumed silica (C), it is preferable that it is the range of 30-300 m <2> / g, The range of 60-200 m <2> / g is more preferable, It is 120-200 m <2> / g The range is more preferred.

As a commercial item of the said hydrophilic type of said fumed silica (C), "Aerosil 50", "Aerosil 90G", "Aerosil 130", "Aerosil 200", "Aerosil" 200CF "," Aerosil 200V "," Aerosil 300 "," Aerosil 300CF "(above, Nippon Aerosil Co., Ltd. product) etc. can be obtained.

Moreover, as a commercial item of a hydrophobic type, "Aerosil DT4", "Aerosil NA200Y", "Aerosil NA50H", "Aerosil NA50Y", "Aerosil NAX50", "Ah" Aerosil R104 "," Aerosil R106 "," Aerosil R202 "," Aerosil R202W90 "," Aerosil R504 "," Aerosil R711 "," Aero Quality R700 "," Aerosil R7200 "," Aerosil R805 "," Aerosil R805VV90 "," Aerosil R812 "," Aerosil 812S "," Aerosil R816 " , "Aerosil R8200", "Aerosil R972", "Aerosil R972V", "Aerosil R974", "Aerosil RA200HS", "Aerosil RX200", `` Aerosil RX300 '', `` Aerosil RX50 '', `` Aerosil RY200 '', `` Aerosil RY200S '', `` Aerosil RY300 '', `` Aerosil RY50 '' (above, Nihon Aerosil Co., Ltd.) etc. can be obtained.

As the usage-amount of the said fumed silica (C), it is more preferable that it is the range of 0.5-2.0 mass parts with respect to 100 mass parts of said urethane prepolymers (A) from the point of a liquid viscosity and a grinding | polishing characteristic. In addition, since the said fumed silica (C) contributes to a continuous bubble in the said range, the polyurethane polishing pad obtained becomes a low independent bubble ratio. Therefore, the slurry holding force of a polyurethane polishing pad improves and polishing characteristics improve.

Next, the urethane resin composition for polishing pads of this invention is demonstrated.

Compounding ratio of the above-mentioned main ingredient and the curing agent for obtaining the urethane resin composition for a polishing pad of the present invention, that is, the group capable of reacting with isocyanate groups in the curing agent containing R value [R] = [compound (B) and water (D) Total mole number] / [total number of moles of isocyanate groups in the prepolymer (A) which is the subject] becomes like this. Preferably it is the range of 0.7-1.1, More preferably, it is the range of 0.8-1.0.

Known conventional additives such as urethane resin compositions for polishing pads of the present invention, antioxidants, defoamers, ultraviolet absorbers, abrasive grains, fillers, pigments, thickeners, flame retardants, plasticizers, lubricants, antistatic agents, heat stabilizers, It can be used at any stage of the manufacturing process.

As said filler, a carbonate, a silicic acid, a silicate, a hydroxide, a sulfate, a borate, a titanate, a metal oxide, a carbon thing, an organic substance, etc. are mentioned, for example.

Next, the polyurethane polishing pad of the present invention and a manufacturing method thereof will be described. The polyurethane polishing pad of this invention is obtained using the said urethane resin composition for polishing pads, For example, it adds and mixes the above additives to the said urethane resin composition for polishing pads as needed, and it predetermined shape It can be injected into a mold, foamed and cured, and the foamed molded article can be taken out from the mold, and processed into slices or the like in a suitable shape such as a sheet.

As the method for producing the polyurethane polishing pad of the present invention, in addition to the above-described water-foaming method, for example, a method of adding hollow beads, mechanical frothing, and a machine for introducing and mixing a non-reactive gas into a mixing chamber Known conventional methods such as foaming and chemical foaming can be employed, and are not particularly limited.

As a specific example of the manufacturing method of the polyurethane polishing pad of this invention, a series of manufacturing methods including [step 1]-[step 5] are mentioned, for example.

[Step 1] Preparation Step of Main (First Component)

For example, a polyisocyanate (a1) and a polyol (a2) are respectively added to a reactor equipped with a nitrogen inlet tube, a cooling condenser, a thermometer, and a cooler, and stirred under a nitrogen atmosphere, preferably in the range of 70 to 90 ° C. More preferably, it reacts in 75-85 degreeC, and synthesize | combines a urethane prepolymer (A), and obtains the main subject containing the said urethane prepolymer (A) and preferably fumed silica (C).

[Step 2] Mixing Step of Main Part and Curing Agent

Subsequently, the main body (first component) containing the urethane prepolymer (A) and the curing agent (second component) containing the compound (B), preferably water (D) and the catalyst (E) are mixed and stirred. To the reaction solution. However, when melting | fusing point of a compound (B) is 100 degreeC or more, it is set as the 3rd component which melt | dissolved water (D) and a catalyst (E) in the compound (B) different from the above, for example, 1st component / agent It is good also as a reaction liquid, mixing and stirring two components / 3rd components.

At the time of mixing, the main component (the first component) containing the urethane prepolymer (A) and the curing agent (the second component) containing the compound (B), and optionally the third component, are added to each tank of the mixing mold machine. The main component (first component) containing the urethane prepolymer (A) is preferably heated to 40 to 80 ° C, and the curing agent (second component) is preferably heated to 40 to 120 ° C, Therefore, the 3rd component is heated to 30-70 degreeC, and each is mixed with a mixing mold machine.

[Step 3] Molding Step

The reaction liquid discharged from the mixing molder is injected into a mold which is preferably warmed to 40 to 120 ° C using a hose or the like.

[Step 4] Curing Step

In the state injected into the mold, the reaction solution is heated and maintained in an appropriate temperature range (for example, in the range of 40 to 120 ° C), foamed and cured, and preferably in a mold of 40 to 120 ° C for 30 minutes to 2 hours. After leaving to stand, the molded article is taken out, preferably after cured under conditions of 100 to 120 ° C. for 8 to 17 hours to obtain a molded article.

[Step 5] Slice Step

The molded article is sliced into a sheet with an appropriate thickness. What is necessary is just to set the sheet thickness after slice according to the objective of grinding | polishing, Although there is no restriction | limiting in particular, For example, the range of 0.6-2.0 mm is preferable.

The polyurethane polishing pad obtained as described above is fixed to a surface plate with, for example, a double-sided tape, and the fixed polyurethane polishing pad is rotated together with the surface plate to always polish polishing slurry containing abrasive grains thereon. While supplying, a semiconductor substrate, an optical substrate, a magnetic substrate, etc. are pressed against a polyurethane polishing pad, and polishing is performed.

Examples of the abrasive include colloidal silica, cerium oxide, zirconium oxide, silicon carbide, alumina and the like.

(Example)

Hereinafter, the present invention will be described in more detail using examples.

Example 1 Manufacture of Polyurethane Polishing Pad (P-1)

37 mass parts of tolylene diisocyanate ("TDI-100" Nippon Polyurethane Co., Ltd. product) was thrown into the four neck round bottom flask provided with the nitrogen inlet tube, the cooling condenser, the thermometer, and the stirrer, and stirring was started. Subsequently, 63 mass parts of polytetramethylene glycol (number average molecular weight 1,000) was thrown in, and it mixed, reaction was performed at 60 degreeC under nitrogen stream for 8 hours, and the urethane prepolymer (A-1) of isocyanate group equivalent 335 was obtained. To the obtained urethane prepolymer (A-1), 1.25 parts by mass of hydrophilic silica (brand name: "Leosilyl QS20L", specific surface area = 220 m 2 / g, manufactured by Tokuyama Co., Ltd.) was added thereto, and was sufficiently mixed with a disper disperser. , As the first component. The isocyanate group equivalent of the obtained 1st component was 342.

Subsequently, 3,3'-dichloro-4,4'-diaminophenylmethane (hereinafter abbreviated as "MBOCA") was melted at 120 ° C to obtain a second component.

Next, polypropylene glycol (hereinafter abbreviated as "PPG"). 100 parts by mass of number average molecular weight 3,000, f = 3, 7.0 parts by mass of ion-exchanged water, 0.5 parts by mass of bis (dimethylaminoethyl) ether and surface tension 4 mass parts of polyether modified silicone foam stabilizers of 21.3 mN / m (25 degreeC) were mix | blended, it was fully stirred and mixed, and it was set as the 3rd component.

Next, the said 1st component, the 2nd component, and the 3rd component were thrown into three tanks of the mixing type | mold elastomer casting machine (the "EA-408 type" Toho Kikai Kogyo Co., Ltd. make), and it degassed under reduced pressure. Subsequently, in the mold (inner dimensions 500 × 500 × 20 mm) warmed to 60 ° C., the first component / second component / third component = 74.1 / 22.0 / 3.9 3350 g (1st + 2nd + 3rd component) was injected | poured in the compounding ratio of mass ratio.

Discharge amount = 7,500 g / min (first + second + third component)

Mixer rotation speed = 3,500 rpm

Introduction of dry air in the mixing chamber

Then, the molded article was taken out immediately after covering the cover of a metal mold | die and hold | maintaining at 60 degreeC for 30 minutes. Moreover, the obtained molded article was after-cure for 16 hours at 110 degreeC.

The obtained molded article was cut out to thickness 1.4mm with the slicer, and the sheet-like polyurethane polishing pad (P-1) was obtained.

Example 3 Manufacture of Polyurethane Polishing Pad (P-3)

Fumed silica hydrophobically modified with hydrophilic silica (brand name: "Leosilyl QS20L") in dimethyl silicone oil (brand name: "Aerosil RY200S", specific surface area = 130 m 2 / g, manufactured by Nippon Aerosil Co., Ltd.) Polyurethane polishing pad (P-2) was obtained like Example 1 except having changed to).

Comparative Example 1 Manufacture of Polyurethane Polishing Pad (P′-1) ≫

Example 1 except having made the 1st component into the urethane prepolymer (A-1) without introducing a fumed silica, and setting it as 1st component / 2nd component / 3rd component = 73.7 / 22.3 / 3.9 (mass ratio) as a compounding ratio. A polyurethane polishing pad (P'-1) was obtained in the same manner.

[Measurement Method for Isocyanate Group Equivalent (NCO Equivalent) in the Prepolymer (A)]

The measurement of the NCO equivalent of a prepolymer (A) is based on JIS K 7301, The sample is melt | dissolved in dry toluene, an excess di-n-butylamine solution is added and reacted, and the remaining di-n-butylamine hydrochloric acid is carried out. It was calculated by reverse titration with a standard solution.

[Measurement method of number average molecular weight]

The number average molecular weight of the polyol used by the Example and the comparative example was calculated | required as follows.

Number average molecular weight = (56,100 × f) / (hydroxyl value + acid value)

In addition, f: functional group

In addition, the measuring method of the hydroxyl value and the acid value was measured according to JISK1557.

[Measuring method of polishing pad thickness]

It measured by the dial gauge (effective number: 0.01 mm) (n = 8), and made the average value into the thickness of a polishing pad.

[Measuring Method of Density of Polishing Pad]

Measure the length (significant number: 0.1 mm) to measure (n = 2), the thickness (significant number: 0.01 mm) to dial gauge (n = 8), and the weight (significant number: 0.01 g) It measured by (n = 2) and calculated by the following formula.

Density (g / cm 3) = average mass / (average length 1 x average length 2 x average thickness)

[Measuring method of hardness of the polishing pad]

It measured according to JIS A 7312.

[Measuring Method of Cell Average Diameter of Polishing Pad]

The cell diameter was measured by the image analysis device.

Device: Pore Scan (made by Goldlucke)

Condition: Position 12

Exposure: 1,000 Gain: 30

Threshould: Auto

5 measurements (batch processing)

300 μm ² or less do not count

[With or without huge cell]

The polyurethane polishing pad obtained in the Example and the comparative example was observed visually, and the presence or absence of the macro cell was confirmed.

In addition, when there existed one cell of 1 mm or more in diameter on a polyurethane polishing pad, it represented with "Yes", and when there was not, it described as "None".

[Method for Measuring Independent Bubble Rate of Polishing Pad]

Two sheets of 38 × 250 mm were cut out from the polishing pad, and two sheets were put together and measured in an “air type apparent volumetric instrument” (1000 type air comparative-type hydrometer manufactured by Tokyo Science, Inc.). It measured according to ASTMD-2856.

[Evaluation method of polishing rate]

The polyurethane polishing pads obtained in Examples and Comparative Examples were stuck to one side of the double-sided tape, and the surface plate of the polishing machine was stuck to the other side of the double-sided tape, and the polishing rate was measured by the following apparatus, conditions, and formula. .

Polishing machine: FAM 18 GPAW (Plated plate made by Speed Fam = 457.2 mm)

Polishing condition:

(Pad pretreatment) The dressing process (flattening of the pad) was performed with the diamond dresser until the line | wire drawn on the pad surface disappeared vertically and horizontally by 2 cm interval. Water supply 200ml / min

(Polishing object) 4 inches of single crystal silicon wafers (102mm t = 0.45mm)

(Slurry) colloidal silica solution PH = 11 (silica concentration = 2%)

(Slurry flow rate) 60 ml / min

50 rpm (banquet type)

(Polishing pressure) 30㎪

(Polishing time) 20 minutes

(Polishing rate) It calculated from the weight difference of the polyurethane polishing pad before and behind polishing. In other words,

Polishing rate (µm / min) = (weight of silicon wafer before polishing (g)-weight of silicon wafer after polishing (g)) x 10000 / (density of single crystal silicon (g / cm 3) x area of silicon wafer (cm 2) ) × Polishing time (minutes)

※ Density of single crystal silicon = 2.329 (g / cm 3)

※ Area of silicon wafer = 20.4 c㎡

[Evaluation method of scratch]

Whether the scratches were scratched on the silicon wafer after polishing by the above-mentioned [evaluation method of polishing rate] was visually observed and evaluated as follows.

No scratch scratches: `` ○ ''

Scratch scratches: `` × ''

[Evaluation method of flatness]

Evaluation of flatness measured the single crystal silicon wafer after grind | polishing by the said [evaluation method of a polishing rate] using the surface roughening machine.

Device: Form Talysurf i120 (by Taylor Hobson)

Condition: Scanning speed: 0.5 mm / minute

Measurement site: 99 mm in 102 mm radial direction is evaluated

Evaluation Criteria: A line having a height difference of ± 1.0 µm having a length of 90 mm or more is evaluated as "○".

A line segment having a height difference of ± 1.0 μm of less than 90 mm is evaluated as “×”.

[Table 1]

It turned out that Example 1 and 2 which are the urethane resin compositions for polishing pads of this invention are excellent in all of a polishing rate, non-scratchability, and flatness. In addition, it was found that the independent bubble ratio was also low.

On the other hand, the comparative example 1 which is an aspect which does not contain a fumed silica (C) was bad in polishing rate and flatness. In addition, it was found that the independent bubble ratio was also high.

Claims (4)

In the urethane resin composition for a polishing pad containing the main body containing the urethane prepolymer (A) which has an isocyanate group, and the hardening | curing agent containing the compound (B) which has a functional group which reacts with an isocyanate group, Fumed silica (C) The urethane resin composition for a polishing pad further containing. The method of claim 1,
The urethane resin composition for polishing pads whose usage-amount of the said fumed silica (C) is 0.5-2 mass parts with respect to 100 mass parts of said urethane prepolymers (A). The method according to claim 1 or 2,
The urethane resin composition for a polishing pad, wherein the fumed silica (C) is hydrophobic fumed silica. The polyurethane polishing pad obtained using the urethane resin composition for polishing pads in any one of Claims 1-3.