Polishing pad, method for manufacturing a polishing pad, and method for polishing the surface of an optical material or semiconductor material.

Abstract

To provide a polishing pad capable of suppressing a defect in a polished object, a method for manufacturing the polishing pad, and a method for polishing a surface of an optical material or a semiconductor material using the polishing pad.SOLUTION: A polishing pad has a polishing layer containing a polyurethane resin, in which the polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component, and the polyol component contains polyether polycarbonate diol represented by the following formula (I). In the formula (I), R1 is a divalent hydrocarbon group having 2 to 10 carbon atoms, a plurality of R1 may be the same or different, n is an integer of 2-30, and m is an integer of 1-20.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polishing pad, a method for manufacturing a polishing pad, and a method for polishing the surface of an optical material or a semiconductor material. The polishing pad of the present invention is used for polishing optical materials, semiconductor wafers, semiconductor devices, hard disk substrates, etc., and is particularly suitable for polishing devices on which an oxide layer, a metal layer, etc., is formed on a semiconductor wafer. [Background technology]

[0002] Optical materials, semiconductor wafers, hard disk substrates, LCD glass substrates, and semiconductor devices require extremely precise flatness. Hard polishing pads are commonly used to polish the surfaces of these various materials, especially the surfaces of semiconductor devices, to a flat surface. Currently, the abrasive layer in many hard polishing pads typically uses a hard polyurethane material obtained by curing an isocyanate-terminated urethane prepolymer, which is a reaction product of an isocyanate component such as tolylene diisocyanate (TDI) and a polyol component containing a high molecular weight polyol such as polytetramethylene ether glycol (PTMG), with a curing agent such as 3,3'-dichloro-4,4'-diaminodiphenylmethane. The high molecular weight polyol that forms the isocyanate-terminated urethane prepolymer forms the soft segment of the polyurethane, and PTMG has traditionally been commonly used as the high molecular weight polyol due to its ease of handling and appropriate rubber elasticity.

[0003] In the polishing of semiconductor devices, the miniaturization and increasing density of integrated circuits in recent years have led to a demand for more stringent suppression of defects such as scratches and organic residues on the surface of the polished object. However, conventional polishing pads using PTMG as a high molecular weight polyol are sometimes insufficient in suppressing defects, and studies are being conducted on using polyols other than PTMG as the high molecular weight polyol. Furthermore, when using polyols other than PTMG as the high molecular weight polyol, it is desirable that the polishing performance, such as the polishing rate, be equal to or better than that of the conventional polishing pads mentioned above.

[0004] Patent Document 1 discloses a polishing pad containing a polyol blend which is a mixture of polypropylene glycol (PPG) and PTMG, a polyamine or a polyamine mixture, and a polyurethane reaction product of toluene diisocyanate. The polishing pad of Patent Document 1 reduces the defect rate by using a mixture of PPG and PTMG as the polyol blend that forms the polyurethane reaction product. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-40737 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, when using a mixture of PPG and PTMG as the high molecular weight polyol, as in the polishing pad described in Patent Document 1, the poor compatibility of PPG and PTMG makes it difficult to achieve complete uniformity. As a result, the polymerization reaction of the isocyanate-terminated urethane prepolymer becomes non-uniform, and consequently, the polishing performance may be unstable and inconsistent. Furthermore, when the entire amount of PTMG as the high molecular weight polyol is replaced with PPG, the resulting isocyanate-terminated urethane prepolymer tends to soften. To prevent this, a new equivalence adjustment between the polyol component and the polyisocyanate component becomes necessary during the production of the isocyanate-terminated urethane prepolymer. In addition, when the inventors investigated the polishing performance of polishing pads in which the entire amount of PTMG as the high molecular weight polyol was replaced with PPG, as shown in Comparative Example 3 described later, defects were suppressed compared to conventional polishing pads using PTMG as the high molecular weight polyol. However, to cope with the miniaturization and high density of integrated circuits in recent years, a higher level of defect suppression is required.

[0007] As described above, there is a need for polishing pads that can suppress defects in the workpiece. Furthermore, there is a need for polishing pads that suppress defects in the workpiece while also having an excellent polishing rate.

[0008] The present invention aims to provide a polishing pad that can suppress defects in a workpiece, a method for manufacturing the polishing pad, and a method for polishing the surface of an optical material or semiconductor material using the polishing pad. Another objective of the present invention is to provide a polishing pad that suppresses defects in a workpiece and has an excellent polishing rate, a method for manufacturing the polishing pad, and a method for polishing the surface of an optical material or semiconductor material using the polishing pad. [Means for solving the problem]

[0009] As a result of diligent research to solve the above problems, the present inventors have found that the above problems can be solved by using a polyether polycarbonate diol having a specific structure as the polyol component that forms the isocyanate-terminated urethane prepolymer, and have completed the present invention. Specific embodiments of the present invention are as follows.

[0010] [1] A polishing pad having a polishing layer containing polyurethane resin, The polyurethane resin is a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component. The polishing pad comprising the polyol component represented by the following formula (I): [ka] (In the above formula (I), R 1 It is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 They may be the same or they may be different. n is an integer between 2 and 30. m is an integer between 1 and 20. [2] R in equation (I) above 1 The polishing pad according to [1], wherein is an n-butylene group and / or a 2-methylbutylene group. [3] The polishing pad according to [1] or [2], wherein the polyether polycarbonate diol contains structural units derived from polytetramethylene ether glycol, and the number average molecular weight of the structural units derived from polytetramethylene ether glycol is 100 to 1500. [4] The polishing pad according to any one of [1] to [3], wherein the number average molecular weight of the polyether polycarbonate diol is 200 to 5000. [5] The polishing pad according to any one of [1] to [4], wherein the polyisocyanate component comprises tolylene diisocyanate. [6] The polishing pad according to any one of [1] to [5], comprising 3,3'-dichloro-4,4'-diaminodiphenylmethane as the curing agent. [7] The polishing pad according to any one of [1] to [6], further comprising the curable resin composition with micro hollow spheres. [8] A method for manufacturing an abrasive pad according to any one of [1] to [7], comprising the step of forming the abrasive layer. A method for polishing the surface of an optical material or a semiconductor material, the method comprising a step of polishing the surface of the optical material or the semiconductor material using the polishing pad according to any one of [1] to [7].

[0011] (Definition) In the present application, "particle" means a residue of fine particles contained in a polishing slurry or the like that adheres to the surface of the object to be polished. In the present application, "pad debris" means debris of the polishing layer generated by abrasion of the surface of the polishing layer on the polishing pad during the polishing process, which adheres to the surface of the object to be polished. In the present application, "scratch" means a scratch on the surface of the object to be polished. In the present application, "defect" is a general term for defects including the above-mentioned particles, pad debris, scratches, etc. In the present application, when representing a numerical range using "X to Y", the range shall include the numerical values X and Y at both ends. [Advantages of the Invention]

[0012] The polishing pad of the present invention can suppress defects in the object to be polished. Further, the polishing pad of the present invention suppresses defects in the object to be polished and has an excellent polishing rate. [Brief Description of the Drawings]

[0013] [Figure 1] It is a graph showing the evaluation results of defects of the polishing pads of Example 1 and Comparative Examples 1 to 3. [Figure 2] It is a graph showing the evaluation results of the polishing rates of the polishing pads of Example 1 and Comparative Examples 1 to 3. [Figure 3] It is a graph showing the evaluation results of defects of the polishing pad of Example 4. [Figure 4] It is a graph showing the evaluation results of the polishing rate of the polishing pad of Example 4. [Embodiments for Carrying Out the Invention]

[0014] (action) The inventors diligently studied the relationship between the polyol component forming the isocyanate-terminated urethane prepolymer and defects. Unexpectedly, they discovered that by using a polyether polycarbonate diol with a specific structure as the polyol component forming the isocyanate-terminated urethane prepolymer, it is possible to obtain a polishing pad that can suppress the occurrence of defects. The detailed reasons for obtaining such properties are not clear, but the following can be inferred.

[0015] The polyether polycarbonate diol (PEPCD) represented by formula (I) above has a carbonate group, and is therefore thought to have lower crystallinity than PTMG. Consequently, the isocyanate-terminated urethane prepolymer formed from this PEPCD is also thought to have lower crystallinity. Lower crystallinity of the isocyanate-terminated urethane prepolymer forming the polishing layer is thought to make it less likely for polishing debris to aggregate and form large clumps, thus suppressing defects in the polished object.

[0016] The following describes the polishing pad of the present invention, a method for manufacturing the polishing pad, and a method for polishing the surface of an optical material or semiconductor material.

[0017] 1. Polishing pad, method for manufacturing a polishing pad The polishing pad of the present invention has a polishing layer containing a polyurethane resin, wherein the polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component, and the polyol component contains a polyether polycarbonate diol represented by the following formula (I). [ka] (In the above formula (I), R 1It is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 They may be the same or they may be different. n is an integer between 2 and 30. m is an integer between 1 and 20.

[0018] The polishing pad of the present invention has a polishing layer containing a polyurethane resin. The polishing layer is positioned in direct contact with the material to be polished, and the rest of the polishing pad may be made of a material for supporting the polishing pad, such as an elastic material like rubber. Depending on the rigidity of the polishing pad, the polishing layer itself can function as the polishing pad.

[0019] The polishing pad of the present invention does not differ significantly in shape from a general polishing pad, except that it can suppress defects in the workpiece, and can be used in the same way as a general polishing pad. For example, it can be used to polish by pressing the polishing layer against the workpiece while rotating the polishing pad, or by pressing the workpiece against the polishing layer while rotating the workpiece.

[0020] The polishing pad of the present invention can be manufactured by generally known manufacturing methods such as mold molding and slab molding. First, a polyurethane block is formed by these manufacturing methods, the block is sliced ​​into a sheet, an polishing layer formed from polyurethane resin is molded, and then it is bonded to a support or the like. Alternatively, the polishing layer can be molded directly onto the support.

[0021] More specifically, the polishing layer has double-sided tape attached to the side of the polishing layer opposite to the polishing surface, and is cut to a predetermined shape to become the polishing pad of the present invention. There are no particular restrictions on the double-sided tape, and any double-sided tape known in the art can be arbitrarily selected and used. Furthermore, the polishing pad of the present invention may have a single-layer structure consisting only of the polishing layer, or it may have a multi-layer structure in which other layers (underlayer, support layer) are attached to the side of the polishing layer opposite to the polishing surface.

[0022] The polished layer is formed by preparing a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and then curing the curable resin composition. The polishing layer can be made from foamed polyurethane resin, and foaming can be achieved by dispersing a foaming agent containing minute hollow spheres in the polyurethane resin. In this case, a curable resin composition containing an isocyanate-terminated urethane prepolymer, a curing agent, and a foaming agent can be prepared, and the polishing layer can be molded by foaming and curing the curable resin composition. The curable resin composition can also be a two-component composition prepared by mixing, for example, liquid A containing an isocyanate-terminated urethane prepolymer and liquid B containing a curing agent component. Other components may be added to either liquid A or liquid B, but if problems occur, the composition can be further divided into multiple liquids and mixed to form three or more liquids.

[0023] (Isocyanate-terminated urethane prepolymer) The isocyanate-terminated urethane prepolymer is a product obtained by reacting a polyol component with a polyisocyanate component, wherein the polyol component contains a polyether polycarbonate diol represented by the above formula (I).

[0024] The NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is preferably less than 600, more preferably between 350 and 550, and most preferably between 400 and 500. By having the NCO equivalent (g / eq) within the above numerical range, a polishing pad with appropriate polishing performance can be obtained.

[0025] (Polyol component) In the above formula (I) representing the polyether polycarbonate diol, R 1 R is a divalent hydrocarbon group having 2 to 10 carbon atoms. 1Examples include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, 1,1-dimethylethylene, n-pentylene, 2,2-dimethylpropylene, 2-methylbutylene, etc. Among them, an n-butylene group and / or a 2-methylbutylene group are particularly preferred. In the above formula (I), a plurality of R 1 may be the same or different, but it is preferred that they are the same. In the above formula (I), n is an integer of 2 to 30, preferably an integer of 3 to 15, and more preferably an integer of 3 to 10. In the above formula (I), m is an integer of 1 to 20, preferably an integer of 1 to 10, and more preferably an integer of 1 to 5. The above polyether polycarbonate diol preferably contains a structural unit derived from polytetramethylene ether glycol, and the structural unit derived from the polytetramethylene ether glycol is preferably a part represented by -(R 1 -O) n - in the above formula (I). The number average molecular weight of the structural unit derived from the polytetramethylene ether glycol is preferably 100 to 1500, more preferably 150 to 1000, and most preferably 200 to 850. The number average molecular weight of the above polyether polycarbonate diol is preferably 200 to 5000, more preferably 500 to 3000, and most preferably 800 to 2500. The structural unit derived from the above polytetramethylene ether glycol and the number average molecular weight of the above polyether polycarbonate diol can be measured as the molecular weight in terms of polystyrene based on gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Column: Ohpak SB-802.5HQ (exclusion limit 10000) Mobile phase: 5 mM LiBr / DMF Flow rate: 0.5 ml / min (26 kg / cm 2 ) Oven: 60 °C Detector: RI 40℃ Sample volume: 20 μl

[0026] The content of the above-mentioned polyether polycarbonate diol relative to the total isocyanate-terminated urethane prepolymer is preferably 25 to 75% by weight, more preferably 35 to 65% by weight, and most preferably 40 to 60% by weight. By having the content of the above-mentioned polyether polycarbonate diol within the above numerical range, defects in the workpiece can be suppressed and a high polishing rate can be achieved.

[0027] Other polyol components in the isocyanate-terminated urethane prepolymer besides the polyether polycarbonate diol mentioned above include low molecular weight polyols, high molecular weight polyols other than the polyether polycarbonate diol mentioned above, or combinations thereof. In the present invention, a low molecular weight polyol is a polyol with a number average molecular weight of 30 to 300, and a high molecular weight polyol is a polyol with a number average molecular weight exceeding 300. The number average molecular weights of the low molecular weight polyol and the high molecular weight polyol other than the polyether polycarbonate diol can be measured by the same method as shown for the structural units derived from polytetramethylene ether glycol and the number average molecular weight of the polyether polycarbonate diol mentioned above.

[0028] Examples of the low molecular weight polyols mentioned above include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, or combinations thereof. Other high molecular weight polyols besides the polyether polycarbonate diols mentioned above include, for example, polyether polyols such as polytetramethylene ether glycol (PTMG), polyethylene glycol, and polypropylene glycol; Polyester polyols such as reaction products of ethylene glycol and adipic acid, or reaction products of butylene glycol and adipic acid; Polycarbonate polyol; Examples include polycaprolactone polyols; or combinations thereof.

[0029] The content of the above polyether polycarbonate diol relative to the total high molecular weight polyol is preferably 80 to 100% by weight, more preferably 85 to 100% by weight, and most preferably 90 to 100% by weight. By having the content of the above polyether polycarbonate diol within the above numerical range, defects in the workpiece can be suppressed and a high polishing rate can be achieved. Furthermore, the above-mentioned high molecular weight polyol may also be made of the above-mentioned polyether polycarbonate diol.

[0030] (Polyisocyanate component) The polyisocyanate components contained in isocyanate-terminated urethane prepolymers include: For example, m-phenylenediisocyanate, p-phenylenediisocyanate, 2,6-Tolylene diisocyanate (2,6-TDI), 2,4-Tolylene diisocyanate (2,4-TDI), Naphthalene-1,4-diisocyanate, Diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-Methylene-bis(cyclohexyl isocyanate)(hydrogenated MDI), 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, Xylylene-1,4-diisocyanate, 4,4'-Diphenylpropanediisocyanate, trimethylene diisocyanate, Hexamethylene diisocyanate, Propylene-1,2-diisocyanate, Butylene-1,2-diisocyanate, Cyclohexylene-1,2-diisocyanate, Cyclohexylene-1,4-diisocyanate, p-phenylenediisothiocyanate, Xylylene-1,4-diisothiocyanate, Examples include etyridine diisothiocyanate, or combinations thereof. Among these, it is preferable to use tolylene isocyanates such as 2,6-tolylene diisocyanate (2,6-TDI) and 2,4-tolylene diisocyanate (2,4-TDI) from the viewpoint of the polishing characteristics and mechanical strength of the resulting polishing pad.

[0031] (Hardening agent) Examples of curing agents included in curable resin compositions include the amine-based curing agents described below. Examples of polyamines that constitute amine-based curing agents include diamines, which are alkylenediamines such as ethylenediamine, propylenediamine, and hexamethylenediamine; aliphatic ring-containing diamines such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; aromatic ring-containing diamines such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (hereinafter abbreviated as MOCA); hydroxyl group-containing diamines such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, especially hydroxyalkylalkylenediamines; or combinations thereof. In addition, trifunctional triamine compounds and polyamine compounds with four or more functions can also be used.

[0032] A particularly preferred curing agent is MOCA, as mentioned above, and the curing agent can also consist of MOCA. The chemical structure of MOCA is as follows.

[0033] [ka]

[0034] The total amount of curing agent used is such that the ratio of moles of NH2 in the curing agent to moles of NCO in the isocyanate-terminated urethane prepolymer (moles of NH2 / moles of NCO) is preferably 0.7 to 1.1, more preferably 0.75 to 1.0, and most preferably 0.8 to 0.95.

[0035] (Microscopic hollow spheres) In the present invention, the curable resin composition may further contain minute hollow spheres. A foam can be formed by mixing micro-hollow spheres with a polyurethane resin. Micro-hollow spheres refer to unfoamed, heat-expandable micro-spherical bodies consisting of an outer shell (polymer shell) made of thermoplastic resin and low-boiling point hydrocarbons enclosed within the outer shell, as well as unfoamed, heat-expandable micro-spherical bodies that have been heated and expanded. As the polymer shell, for example, thermoplastic resins such as acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, and vinyl chloride-ethylene copolymer can be used. Similarly, as the low-boiling point hydrocarbons enclosed within the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether, or combinations thereof can be used.

[0036] (Other ingredients) Other catalysts commonly used in this industry may be added to the curable resin composition. Furthermore, the polyisocyanate component described above can also be added to the curable resin composition later. The weight ratio of the additional polyisocyanate component to the total weight of the isocyanate-terminated urethane prepolymer and the additional polyisocyanate component is preferably 0.1 to 10% by weight, more preferably 0.5 to 8% by weight, and particularly preferably 1 to 5% by weight. As the polyisocyanate component to be added to the polyurethane resin curable composition, any of the above-mentioned polyisocyanate components can be used without particular limitation, but 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI) is preferred.

[0037] 2. A method for polishing the surface of an optical material or semiconductor material. The present invention provides a method for polishing the surface of an optical material or semiconductor material, which includes the step of polishing the surface of the optical material or semiconductor material using the polishing pad described above. The present invention provides a method for polishing the surface of an optical material or semiconductor material, which may further include the step of supplying a slurry to the surface of a polishing pad, the surface of the optical material or semiconductor material, or both.

[0038] (slurry) The liquid components in the slurry are not particularly limited, but include water (pure water), acids, alkalis, organic solvents, or combinations thereof, and are selected depending on the material of the object to be polished and the desired polishing conditions. Preferably, the slurry has water (pure water) as its main component, and preferably contains 80% by weight or more of water relative to the total slurry. The abrasive components in the slurry are not particularly limited, but include silica, zirconium silicate, cerium oxide, aluminum oxide, manganese oxide, or combinations thereof. The slurry may also contain other components such as organic substances soluble in the liquid components or pH adjusters. [Examples]

[0039] The present invention will be experimentally explained by the following examples, but the following explanation is not intended to be interpreted as limiting the scope of the present invention to these examples.

[0040] (material) The materials used in Examples 1-7 and Comparative Examples 1-3, described below, are listed below.

[0041] • Polyether polycarbonate diol (used as a raw material for isocyanate-terminated urethane prepolymers) PEPCD(1)···A polyether polycarbonate diol (1) containing structural units derived from polytetramethylene ether glycol with a number average molecular weight of 250, and having a number average molecular weight of 1000 (in formula (I) above, multiple R 1 Both are n-butylene, and are polyether polycarbonate diols with n = 3.2 and m = 2.8. Details are shown in Table 1 below. PEPCD(2)~(4)...each is a polyether polycarbonate diol (2)~(4) (as with PEPCD(1) above, details are shown in Table 1 below.)

[0042] • Isocyanate-terminated urethane prepolymer: Prepolymer (1)...A urethane prepolymer with an NCO equivalent of 420, containing 43.8% by weight of 2,4-tolylene diisocyanate as the polyisocyanate component, 50.4% by weight of a polyether polycarbonate diol represented by the above formula (I), containing structural units derived from polytetramethylene ether glycol with a number average molecular weight of 250 and a number average molecular weight of 1000, and 5.8% by weight of diethylene glycol as the polyol component. *The content (by weight) of each component represents the value when the entire urethane prepolymer is considered to be 100% by weight. The same applies to prepolymers (2) to (4) below. Prepolymer (2)...A urethane prepolymer with an NCO equivalent of 420, containing 40.7% by weight of 2,4-tolylene diisocyanate as a polyisocyanate component, 27.9% by weight of polytetramethylene ether glycol with a number average molecular weight of 650, 27.9% by weight of polytetramethylene ether glycol with a number average molecular weight of 1000, and 3.5% by weight of diethylene glycol as polyol components. Prepolymer (3)...A urethane prepolymer with an NCO equivalent of 440, containing 44.5% by weight of 2,4-tolylene diisocyanate as a polyisocyanate component, and 48.2% by weight of polytetramethylene ether glycol with a number average molecular weight of 650 and 7.3% by weight of diethylene glycol as polyol components. Prepolymer (4)...A urethane prepolymer with an NCO equivalent of 500, containing 35.6% by weight of 2,4-tolylene diisocyanate as the polyisocyanate component, and 59.4% by weight of polypropylene glycol with a number average molecular weight of 1000 and 5.0% by weight of diethylene glycol as the polyol components. Prepolymers (5) to (10) are detailed in Table 2 below. The values ​​for each component shown in Table 2 represent the weight of each component when the total urethane prepolymer is assumed to be 1000 parts by weight. For example, the prepolymer (5) shown in Table 2 is a urethane prepolymer with an NCO equivalent of 500, containing 375 parts by weight of 2,4-tolylene diisocyanate as a polyisocyanate component, 562 parts by weight of the above-mentioned PEPCD(1) as a high molecular weight polyol component, and 63 parts by weight of diethylene glycol as a low molecular weight polyol component. The content of 2,4-tolylene diisocyanate, PEPCD(1), and diethylene glycol relative to the total prepolymer (5) is 37.5% by weight, 56.2% by weight, and 6.3% by weight, respectively.

[0043] [Table 1]

[0044] [Table 2]

[0045] • Hardener: MOCA···3,3'-Dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (NH2 equivalent = 133.5)

[0046] • Microscopic hollow spheres: Expancel461DU20 (manufactured by Nippon Filight Co., Ltd.) Expancel461DE20d70 (manufactured by Nippon Filight Co., Ltd.)

[0047] (Example 1) 100g of prepolymer (1) was prepared as component A, 28.6g of MOCA (a curing agent) as component B, and 3.0g of micro hollow spheres (Expancel 461DU20) as component C. The proportions of each component are indicated in grams, but the required weight (parts) should be prepared according to the size of the block. The following calculations will also be in grams (parts). Component A and component C were mixed, and both the mixture of component A and component C and component B were pre-degassed under reduced pressure. Then, the mixture of component A and component C and component B were fed into a mixer to obtain a mixture of component A, component B, and component C. The ratio of the number of moles of NH2 in MOCA of component B to the number of moles of NCO in the prepolymer of component A in the obtained mixture of component A, component B, and component C (moles of NH2 / moles of NCO) was 0.90. The mixture of components A, B, and C was poured into a mold (850mm x 850mm square) heated to 80°C and primary cured at 80°C for 30 minutes. The formed resin foam was removed from the mold and secondary cured in an oven at 120°C for 4 hours. After the resulting resin foam was allowed to cool to 25°C, it was heated again in an oven at 120°C for 5 hours. The resulting resin foam was sliced ​​to a thickness of 1.3mm in the thickness direction to create a urethane sheet, and double-sided tape was attached to the back of this urethane sheet to create a polishing pad.

[0048] (Example 2) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (1) as component A and 28.6g of MOCA as component B were replaced with 100g of prepolymer (5) as component A and 24.0g of MOCA as component B. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0049] (Example 3) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (1) as component A and 28.6g of MOCA as component B were replaced with 100g of prepolymer (6) as component A and 20.0g of MOCA as component B. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0050] (Example 4) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (7) was prepared as component A instead of 100g of prepolymer (1) of component A in Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0051] (Example 5) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (8) was prepared as component A instead of 100g of prepolymer (1) of component A in Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0052] (Example 6) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (9) was prepared as component A instead of 100g of prepolymer (1) of component A in Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0053] (Example 7) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (10) was prepared as component A instead of 100g of prepolymer (1) as component A in Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0054] (Comparative Example 1) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 100g of prepolymer (2) was prepared as component A instead of 100g of prepolymer (1) of component A in Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0055] (Comparative Example 2) A urethane sheet was prepared and a polishing pad was obtained in the same manner as in Example 1, except that instead of 100g of prepolymer (1) as component A and 28.6g of MOCA as component B in Example 1, 100g of prepolymer (3) was prepared as component A and 27.3g of MOCA, a curing agent, was prepared as component B. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0056] (Comparative Example 3) A urethane sheet was prepared and a polishing pad was obtained in the same manner as in Example 1, except that instead of 100g of prepolymer (1) as component A, 28.6g of MOCA as component B, and 3.0g of micro hollow spheres (Expancel461DU20) as component C in Example 1, 100g of prepolymer (4) as component A, 24.0g of MOCA as the curing agent as component B, and 2.5g of micro hollow spheres (Expancel461DE20d70) as component C were prepared. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.90.

[0057] (Evaluation method) For each of Examples 1 and 4 and Comparative Examples 1 to 3, the following measurements were taken for the urethane sheets (before the application of double-sided tape) or polishing pads: (1) thickness, density, D hardness, tensile strength, and tear strength; (2) defect; and (3) polishing rate. Similarly, for each of Examples 2, 3, and 5 to 7, the following measurements were taken for the urethane sheets (before the application of double-sided tape): (1) thickness, density, D hardness, tensile strength, and tear strength. The measurement results are shown in Tables 3 to 8 and Figures 1 to 4 below.

[0058] (1) Thickness, density, hardness (D), tensile strength, and tear strength (Thickness) The thickness (mm) of the urethane sheet was measured in accordance with the Japanese Industrial Standard (JIS K 6550).

[0059] (density) Density of urethane sheet (g / cm³) 3 The measurements were taken in accordance with the Japanese Industrial Standard (JIS K 6505).

[0060] (D hardness) The D hardness of the urethane sheets was measured using a D-type hardness tester in accordance with the Japanese Industrial Standard (JIS-K-6253). Here, the measurement sample was obtained by stacking multiple urethane sheets as needed, so that the total thickness was at least 4.5 mm.

[0061] (Tensile strength) The urethane sheet was cut into a dumbbell shape as specified in the Japanese Industrial Standard (JIS 6550) for measuring tensile strength, and the tensile strength (kg / mm²) was measured according to the Japanese Industrial Standard (JIS 6550) at a tensile speed of 100 mm / min and a test temperature of 20°C. 2 ) was measured.

[0062] (tear strength) A urethane sheet was cut into a rectangular shape with cuts as specified in the Japanese Industrial Standard (JIS 6550) for measuring tear strength, and the tear strength (kg / mm²) was measured according to the Japanese Industrial Standard (JIS 6550) at a tearing speed of 100 mm / min and a test temperature of 20°C. 2 ) was measured.

[0063] (2) Defect The polishing pad was placed in a designated position on the polishing device using double-sided tape with acrylic adhesive, and polishing was performed under the following polishing conditions. Then, using the high-sensitivity measurement mode of a surface inspection device (KLA-Tencor, Surfscan SP2XP), defects (surface defects) with a size of 90 nm or larger were detected on substrates that had undergone polishing treatment for the 5th, 15th, and 25th polishing stages. For each detected defect, an SEM (KLA-Tencor, eDR-5210) was used to analyze SEM images taken with the measurement mode: ELECTRON_OPTICS, measurement conditions: ELECTRON_LANDING_ENERGY 300eV, BEAM_CURRENT 100pA. The number of particles, pad debris, and scratches was then counted according to their respective classifications. The results are shown in Tables 5 and 6 and Figures 1 and 3. The fewer the number of "particles," "pad debris," and "scratch" defects, the better the results are in terms of fewer defects.

[0064] <Conditions for polishing test> • Polishing machine used: Ebara Corporation, F-REX300X Disk: 3MA188 (#100) • Rotation speed: (Surface plate) 85 rpm, (Top ring) 86 rpm • Polishing pressure: 3.5 psi • Abrasive: Manufactured by Fujimi Incorporated, part number: PL6115 (PL6115 concentrate: pure water = 1:1 by weight ratio mixture used) • Abrasive temperature: 20°C • Abrasive discharge rate: 200 ml / min • Workpiece used (object to be polished): A substrate on a 12-inch silicon wafer with tetraethoxysilane deposited on it using PE-CVD to an insulating film thickness of 1 μm. • Pad break: 35N 10 minutes Conditioning: Ex-situ, 35N, 4 scans • Number of sheets polished: 25 sheets

[0065] (3) Polishing rate The polishing pad was placed in a predetermined position on the polishing device using double-sided tape with acrylic adhesive, and polishing was performed under the polishing conditions described in "(2) Defect" above. The polishing rate (in Å) was then measured for the 5th, 15th, and 25th substrates. The results are shown in Tables 7 and 8 and Figures 2 and 4.

[0066] [Table 3]

[0067] [Table 4]

[0068] [Table 5]

[0069] [Table 6]

[0070] [Table 7]

[0071] [Table 8]

[0072] From the results in Tables 5 and 6 and Figures 1 and 3, it was found that the polishing pads of Examples 1 and 4, which used a urethane prepolymer containing polyether polycarbonate diol, produced significantly fewer defects and suppressed the occurrence of defects compared to the polishing pads of Comparative Examples 1 and 2, which used a urethane prepolymer containing polytetramethylene ether glycol, and the polishing pad of Comparative Example 3, which used a urethane prepolymer containing polypropylene glycol. In particular, unlike the polishing pads of Comparative Examples 1 to 3, the polishing pads of Examples 1 and 4 did not show any defects related to pad debris regardless of the number of pads polished, demonstrating their superior ability to suppress defects. Furthermore, the results from Tables 7 and 8 and Figures 2 and 4 show that the polishing pads of Examples 1 and 4 had polishing rates equal to or better than those of the polishing pads of Comparative Examples 1 to 3, indicating superior polishing performance. From the above, it was found that polishing pads formed using an isocyanate-terminated urethane prepolymer containing a polyether polycarbonate diol represented by the above formula (I) can suppress the occurrence of defects during polishing and also exhibit excellent polishing rates.

Claims

1. A polishing pad having a polyurethane resin polishing layer, The polished layer is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, wherein the number of moles of NCO in the isocyanate-terminated urethane prepolymer is the number of moles of NH in the curing agent. ２ The ratio of moles (NH ２ The ratio of moles of (NCO) is 0.7 to 1.1, and the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component. The abrasive pad comprising a polyol component represented by the following formula (I), wherein the content of the polyol component relative to the entire isocyanate-terminated urethane prepolymer is 25 to 75% by weight: 【Chemistry 1】 (In the above formula (I), R １ is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R １ They may be the same or they may be different. n is an integer between 2 and 30. m is an integer between 1 and 20.

2. R in formula (I) １ The polishing pad according to claim 1, wherein is an n-butylene group and / or a 2-methylbutylene group.

3. The polishing pad according to claim 1 or 2, wherein the polyether polycarbonate diol contains structural units derived from polytetramethylene ether glycol, and the number average molecular weight of the structural units derived from polytetramethylene ether glycol is 100 to 1500.

4. The polishing pad according to any one of claims 1 to 3, wherein the number average molecular weight of the polyether polycarbonate diol is 200 to 5000.

5. The polishing pad according to any one of claims 1 to 4, wherein the polyisocyanate component is tolylene diisocyanate.

6. The polishing pad according to any one of claims 1 to 5, wherein the curing agent is 3,3'-dichloro-4,4'-diaminodiphenylmethane.

7. The polishing pad according to any one of claims 1 to 6, wherein the curable resin composition further comprises micro hollow spheres.

8. A method for manufacturing an abrasive pad according to any one of claims 1 to 7, comprising the step of forming the abrasive layer.

9. A method for polishing the surface of an optical material or a semiconductor material, comprising the step of polishing the surface of the optical material or a semiconductor material using a polishing pad according to any one of claims 1 to 7.

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