Chemical mechanical polishing pad

Abstract

Provided is a chemical mechanical polishing pad containing a hydrogenated block copolymer that has an aromatic vinyl polymer block and a hydrogenated polymer block of a conjugated diene polymer, the chemical mechanical polishing pad having a groove or a hole.

Description

Chemical Mechanical Polishing Pads

[0001] The present invention relates to a chemical mechanical polishing pad.

[0002] In recent years, chemical mechanical polishing (CMP) has been widely used in the manufacture of wafers and the like. In CMP, a slurry is supplied to the surface of a chemical mechanical polishing pad, and the polished object, such as a wafer, is brought into contact with the polished object to polish it. As a chemical mechanical polishing pad used in such chemical mechanical polishing, for example, a urethane foam-based chemical mechanical polishing pad is known.

[0003] On the other hand, since abrasive grains and polishing debris adhere to the polishing surface of a chemical mechanical polishing pad during polishing, which reduces the polishing performance, the surface of the chemical mechanical polishing pad is scraped off (dressed) using a dresser to restore the polishing surface. Therefore, chemical mechanical polishing pads are consumables, and from the viewpoint of reducing the frequency of replacement of chemical mechanical polishing pads and reducing costs, chemical mechanical polishing pads are desired to have excellent wear resistance.

[0004] For example, Patent Document 1 discloses a chemical mechanical polishing pad having a polishing layer formed from a composition containing (A) polyethylene, (B) a styrene-butadiene copolymer, and (C) a water-soluble substance. The chemical mechanical polishing pad disclosed in Patent Document 1 is said to have excellent in-plane uniformity of the polishing amount on the polished surface, few scratches, and low sliding resistance, but the chemical mechanical polishing pad disclosed in Patent Document 1 does not necessarily have sufficient wear resistance.

[0005] JP 2009-252891 A

[0006] An object of the present invention is to provide a chemical mechanical polishing pad that is excellent in wafer transportability and wear resistance.

[0007] The present inventors have conducted studies to achieve the above-mentioned object and have found that the above-mentioned object can be achieved by a chemical mechanical polishing pad containing a hydrogenated block copolymer having an aromatic vinyl polymer block and a hydrogenated polymer block of a conjugated diene polymer, the chemical mechanical polishing pad having grooves or holes, and have thus completed the present invention.

[0008] That is, according to the present invention, the following chemical mechanical polishing pad is provided.

[0009] [1] A chemical mechanical polishing pad containing a hydrogenated block copolymer having an aromatic vinyl polymer block and a hydrogenated conjugated diene polymer block, the chemical mechanical polishing pad having grooves or holes. [2] The chemical mechanical polishing pad according to [1], wherein the hydrogenated block copolymer is hydrogenated block copolymer A represented by the following general formula (A) or hydrogenated block copolymer B represented by the following general formula (B): ａ -HD ａ -Ar2 ａ (A) (In the above general formula (A), Ar1 ａ and Ar2 ａ is an aromatic vinyl polymer block, and HD ａ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ａ Weight average molecular weight (Mw(Ar2 ａ )) ratio (Mw(Ar2 ａ ) / Mw(Ar1 ａ )) is 3.0 to 20. ) Ar1 ｂ -HD ｂ -Ar2 ｂ (B) (In the above general formula (B), Ar1 ｂ and Ar2 ｂ is an aromatic vinyl polymer block, and HD ｂ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) with respect to Ar2 ｂWeight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ [3] The chemical mechanical polishing pad according to [2], containing both the hydrogenated block copolymer A and the hydrogenated block copolymer B as the hydrogenated block copolymer. [4] In the general formula (A) and the general formula (B), Ar1 ａ , Ar1 ｂ , and Ar2 ｂ The weight average molecular weight of each of the above ranges from 2,000 to 40,000, and HD ａ and HD ｂ and (b) a weight average molecular weight of the hydrogenated block copolymer A to the hydrogenated block copolymer B, each of which is in the range of 10,000 to 300,000. [5] The chemical mechanical polishing pad according to [3] or [4], wherein the weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B is 10 / 90 to 80 / 20. [6] The chemical mechanical polishing pad according to any one of [1] to [5], wherein the proportion of the aromatic vinyl monomer units in all repeating units of the hydrogenated block copolymer is 20 to 60 wt %. [7] The chemical mechanical polishing pad according to any one of [1] to [6], further containing expanded particles or crosslinkable hollow particles.

[0010] According to the present invention, a chemical mechanical polishing pad having excellent wafer transportability and wear resistance can be provided.

[0011] FIG. 1 is a schematic diagram of a chemical mechanical polishing apparatus 10 according to one embodiment of the present invention.

[0012] <Chemical Mechanical Polishing Pad> The chemical mechanical polishing pad of the present invention is a chemical mechanical polishing pad containing a hydrogenated block copolymer having an aromatic vinyl polymer block and a hydrogenated polymer block of a conjugated diene polymer, and is provided with grooves or holes.

[0013] (Hydrogenated Block Copolymer) The hydrogenated block copolymer used in the present invention is a block copolymer having an aromatic vinyl polymer block and a hydrogenated polymer block of a conjugated diene polymer.

[0014] The hydrogenated block copolymer used in the present invention may be any copolymer having an aromatic vinyl polymer block and a hydrogenated conjugated diene polymer block, but preferably contains a hydrogenated block copolymer A represented by the following general formula (A): ａ -HD ａ -Ar2 ａ (A)

[0015] In the above general formula (A), Ar1 ａ and Ar2 ａ is an aromatic vinyl polymer block, and HD ａ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ａ Weight average molecular weight (Mw(Ar2 ａ )) ratio (Mw(Ar2 ａ ) / Mw(Ar1 ａ )) is 3.0 to 20.

[0016] Aromatic vinyl polymer block Ar1 of hydrogenated block copolymer A ａ , Ar2 ａ is a polymer block composed of aromatic vinyl monomer units.

[0017] The aromatic vinyl monomer used to form the aromatic vinyl monomer unit is not particularly limited as long as it is an aromatic vinyl compound. Examples of aromatic vinyl compounds include styrene; alkyl-substituted styrenes such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, and 5-t-butyl-2-methylstyrene; halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, and 2,4-dibromostyrene; and vinylnaphthalene. Among these, styrene is preferred. These aromatic vinyl monomers can be used alone or in combination of two or more in each aromatic vinyl polymer block. Furthermore, the same aromatic vinyl monomer may be used in each aromatic vinyl polymer block, or different aromatic vinyl monomers may be used. The content of aromatic vinyl monomer units in each aromatic vinyl polymer block is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably substantially 100% by weight, based on the total weight of the aromatic vinyl polymer block.

[0018] In addition, the aromatic vinyl polymer block Ar1 constituting the hydrogenated block copolymer A ａ , Ar2 ａ may contain a monomer unit other than an aromatic vinyl monomer unit. Examples of the monomer constituting the monomer unit other than an aromatic vinyl monomer unit include a conjugated diene monomer such as 1,3-butadiene or isoprene (2-methyl-1,3-butadiene); an α,β-unsaturated nitrile monomer; an unsaturated carboxylic acid or acid anhydride monomer; an unsaturated carboxylic acid ester monomer; and a non-conjugated diene monomer.

[0019] The content of monomer units other than aromatic vinyl monomer units in each aromatic vinyl polymer block is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably substantially 0% by weight, based on the total weight of the aromatic vinyl polymer block.

[0020] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A ａ is a polymer block constituted by conjugated diene monomer units, and at least a portion of the conjugated diene monomer units constituting the polymer block are hydrogenated.

[0021] The conjugated diene monomer used to form the conjugated diene monomer units is not particularly limited as long as it is a conjugated diene compound. Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. Among these, from the viewpoint of polymerization reactivity, it is preferable to use 1,3-butadiene and / or isoprene, and it is particularly preferable to use isoprene. These conjugated diene monomers can be used alone or in combination of two or more types in each hydrogenated polymer block. Furthermore, the same conjugated diene monomer may be used in each hydrogenated polymer block, or different conjugated diene monomers may be used. The content of the conjugated diene monomer units (including hydrogenated conjugated diene monomer units) in each hydrogenated polymer block is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably substantially 100% by weight, based on the total weight of the conjugated diene polymer block.

[0022] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A ａmay contain a monomer unit other than the conjugated diene monomer unit. Examples of the monomer constituting the monomer unit other than the conjugated diene monomer unit include aromatic vinyl monomers such as styrene and α-methylstyrene; α,β-unsaturated nitrile monomers; unsaturated carboxylic acid or acid anhydride monomers; unsaturated carboxylic acid ester monomers; and non-conjugated diene monomers.

[0023] The content of monomer units other than conjugated diene monomer units (including hydrogenated conjugated diene monomer units) in each hydrogenated polymer block is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably substantially 0% by weight, based on the total weight of the conjugated diene polymer block.

[0024] The hydrogenated block copolymer A is Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ａ Weight average molecular weight (Mw(Ar2 ａ )) ratio (Mw(Ar2 ａ ) / Mw(Ar1 ａ )) is in the range of 3.0 to 20, and therefore, the aromatic vinyl polymer block Ar1 has a relatively small weight average molecular weight. ａ , hydrogenated polymer block HD of conjugated diene polymer ａ and an aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight ａ It is a hydrogenated product of an asymmetric aromatic vinyl-conjugated diene-aromatic vinyl block copolymer composed of these units linked in this order.

[0025] In the hydrogenated block copolymer A, Mw(Ar2 ａ ) / Mw(Ar1 ａ ) is in the range of 3.0 to 20. ａ ) / Mw(Ar1 ａ ) is preferably in the range of 3.1 to 17, more preferably in the range of 3.2 to 14, and even more preferably in the range of 3.3 to 11. ａ ) / Mw(Ar1 ａBy setting the molecular weight (Mw) and number average molecular weight (Mn) of the polymer or polymer block within the above range, the resulting chemical mechanical polishing pad can have excellent wear resistance. In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer or polymer block are determined as polystyrene-equivalent values ​​measured by high performance liquid chromatography.

[0026] In addition, the aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight that constitutes the hydrogenated block copolymer A ａ Weight average molecular weight (Mw(Ar1 ａ )) is preferably 2,000 to 40,000, more preferably 2,500 to 30,000, and even more preferably 3,000 to 10,000.

[0027] In addition, the aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight that constitutes the hydrogenated block copolymer A ａ Weight average molecular weight (Mw(Ar2 ａ )) is preferably 5,000 to 250,000, more preferably 8,000 to 120,000, even more preferably 10,000 to 100,000, and still more preferably 10,000 to 80,000.

[0028] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A ａ Weight average molecular weight (Mw(HD ａ )) is preferably 10,000 to 300,000, more preferably 15,000 to 300,000, even more preferably 15,000 to 150,000, and particularly preferably 20,000 to 80,000.

[0029] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A ａThe vinyl bond content (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is preferably 1 to 80 mol %, more preferably 2 to 75 mol %, and even more preferably 3 to 70 mol %. By setting the vinyl bond content within the above range, the resulting chemical mechanical polishing pad can be made to have better wear resistance. In addition, the hydrogenated polymer block HD ａ The vinyl bond content of the hydrogenated polymer block of the conjugated diene polymer may be 4 to 30 mol %, 5 to 20 mol %, or 5 to 15 mol %. １ It can be determined by H-NMR.

[0030] The content of aromatic vinyl monomer units relative to the total monomer units of the hydrogenated block copolymer A is not particularly limited, but is preferably 30 to 95% by weight, more preferably 35 to 90% by weight, even more preferably 40 to 87% by weight, and particularly preferably 43 to 85% by weight. The content of aromatic vinyl monomer units relative to the total monomer units of the hydrogenated block copolymer A can be determined based on the detection intensity ratio between a differential refractometer and an ultraviolet detector in high performance liquid chromatography measurement.

[0031] The weight average molecular weight of the hydrogenated block copolymer A as a whole is not particularly limited, but is preferably 20,000 to 500,000, more preferably 25,000 to 300,000, and even more preferably 30,000 to 150,000. The weight average molecular weight (Mw(Ar1)) of each polymer block constituting the hydrogenated block copolymer A is ａ ), Mw(Ar2 ａ ), Mw(HD ａ ) and the weight average molecular weight of the hydrogenated block copolymer A as a whole within the above-mentioned preferred range, the resulting chemical mechanical polishing pad can be made to have better wear resistance.

[0032] The hydrogenated block copolymer preferably contains a hydrogenated block copolymer B represented by the following general formula (B): ｂ -HD ｂ -Ar2ｂ (B)

[0033] In the above general formula (B), Ar1 ｂ and Ar2 ｂ is an aromatic vinyl polymer block, and HD ｂ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ ) is 0.95 to 1.05.

[0034] In this case, the hydrogenated block copolymer B represented by the general formula (B) may be contained in place of the hydrogenated block copolymer A represented by the general formula (A). In addition to the hydrogenated block copolymer A represented by the general formula (A), the hydrogenated block copolymer B represented by the general formula (B) may be contained. In this case, the hydrogenated block copolymer can be a hydrogenated block copolymer composition containing the hydrogenated block copolymer A and the hydrogenated block copolymer B.

[0035] The hydrogenated block copolymer B is a conjugated diene polymer block HD. ｂ At both ends of each of the two aromatic vinyl polymer blocks Ar1 ｂ , Ar2 ｂ The hydrogenated block copolymer B is a hydrogenated product of an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer, which is composed of two aromatic vinyl polymer blocks Ar1 and Ar2. ｂ , Ar2 ｂ Weight average molecular weight (Mw(Ar1 ｂ ), Mw(Ar2 ｂ )) is Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ ) is 0.95 to 1.05.

[0036] Two aromatic vinyl polymer blocks Ar1 constituting the hydrogenated block copolymer B ｂ , Ar2 ｂ Weight average molecular weight (Mw(Ar1 ｂ ), Mw(Ar2 ｂ )) are each preferably 2,000 to 40,000, more preferably 2,500 to 30,000, and even more preferably 3,000 to 10,000. ｂ , Ar2 ｂ Weight average molecular weight (Mw(Ar1 ｂ ), Mw(Ar2 ｂ )) may be the same as or different from each other, but are preferably substantially the same. ｂ Weight average molecular weight (Mw(Ar1 ｂ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ )) should be in the range of 0.95 to 1.05, preferably in the range of 0.97 to 1.03, more preferably in the range of 0.99 to 1.01, and substantially Mw(Ar2 ｂ ) / Mw(Ar1 ｂ )=1.

[0037] In addition, when the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, these two aromatic vinyl polymer blocks Ar1 ｂ , Ar2 ｂ At least one polymer block of the ｂ ), Mw(Ar2 ｂ )) is an aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight that constitutes the hydrogenated block copolymer A. ａ Weight average molecular weight (Mw(Ar1 ａ)) may be equal to or different from Ar1), but it is more preferable that they are substantially equal to each other. ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) ratio (Mw(Ar1 ｂ ) / Mw(Ar1 ａ )) may be in the range of 0.9 to 2.2, and Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ａ )) may be in the range of 0.9 to 2.2. ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) ratio (Mw(Ar1 ｂ ) / Mw(Ar1 ａ )) is in the range of 0.95 to 1.05, or Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ａ )) is preferably in the range of 0.95 to 1.05.

[0038] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B ｂ Weight average molecular weight (Mw(HD ｂ )) is preferably 10,000 to 300,000, more preferably 15,000 to 300,000, even more preferably 15,000 to 150,000, and particularly preferably 20,000 to 80,000.

[0039] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B ｂThe vinyl bond content (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is preferably 1 to 80 mol %, more preferably 2 to 75 mol %, and even more preferably 3 to 70 mol %. By setting the vinyl bond content within the above range, the resulting chemical mechanical polishing pad can be made to have better wear resistance. Furthermore, from the viewpoint of achieving even better wear resistance, the hydrogenated polymer block HD ｂ The vinyl bond content of the hydrogenated polymer block of the conjugated diene polymer may be 4 to 30 mol %, 5 to 20 mol %, or 5 to 15 mol %. １ In the case where the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B can be determined by H-NMR. ｂ The vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A is ａ For example, the vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A is preferably substantially equal to ａ The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B with respect to the vinyl bond content of ｂ It is preferable that the ratio of the vinyl bond content of the copolymer to the vinyl bond content of the copolymer is in the range of 0.95 to 1.05.

[0040] In the case where the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, when the hydrogenated block copolymer composition is produced by a production method using a coupling agent, such as a production method for a hydrogenated block copolymer composition having steps (1a) to (6a) described below, the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B may be used. ｂHowever, Ar1 may contain a residue of a coupling agent. Specifically, the hydrogenated block copolymer B may be a compound represented by the following formula: ｂ - (HD ｂ’ -X-HD ｂ’ ’ ) -Ar2 ｂ That is, as shown in the above formula, the hydrogenated polymer block HD of the conjugated diene polymer ｂ is coupled to HD via the residue X of the coupling agent. ｂ’ , H.D. ｂ’ ’ Examples of the residue X of the coupling agent include residues of bifunctional coupling agents exemplified in the method for producing a hydrogenated block copolymer composition having steps (1a) to (6a) described below.

[0041] The content of aromatic vinyl monomer units relative to the total monomer units of hydrogenated block copolymer B is not particularly limited, but is preferably 5 to 40 wt %, more preferably 10 to 38 wt %, and even more preferably 15 to 35 wt %. By setting the content of aromatic vinyl monomer units within the above range, the resulting chemical mechanical polishing pad can be made to have superior wear resistance. The content of aromatic vinyl monomer units relative to the total monomer units of hydrogenated block copolymer A can be determined based on the detection intensity ratio between a differential refractometer and an ultraviolet detector in high-performance liquid chromatography measurement.

[0042] The weight average molecular weight of the hydrogenated block copolymer B as a whole is not particularly limited, but is preferably 20,000 to 200,000, more preferably 25,000 to 150,000, and even more preferably 30,000 to 70,000. The weight average molecular weight (Mw(Ar1)) of each polymer block constituting the hydrogenated block copolymer B is ｂ ), Mw(Ar2 ｂ ), Mw(HD ｂ ) and the weight average molecular weight of the hydrogenated block copolymer B as a whole within the above-mentioned preferred range, the resulting chemical mechanical polishing pad can be made to have better wear resistance.

[0043] When the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, the molecular weight distributions of the hydrogenated block copolymer A and hydrogenated block copolymer B constituting the hydrogenated block copolymer composition, and of each polymer block constituting these, expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) [(Mw) / (Mn)], are not particularly limited, but are each preferably 1.1 or less, and more preferably 1.05 or less.

[0044] The weight ratio (A / B) of hydrogenated block copolymer A to hydrogenated block copolymer B contained in the hydrogenated block copolymer composition is not particularly limited, but is preferably 10 / 90 to 80 / 20. The weight ratio (A / B) is more preferably 12 / 88 to 60 / 40, and even more preferably 15 / 85 to 50 / 50. By setting the weight ratio of hydrogenated block copolymer A to hydrogenated block copolymer B within the above range, the resulting chemical mechanical polishing pad can be made to have excellent wear resistance. The weight ratio (A / B) of hydrogenated block copolymer A to hydrogenated block copolymer B can be determined from the area ratio of the peaks corresponding to each block copolymer in a chart obtained by high-performance liquid chromatography.

[0045] When the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, the hydrogenated block copolymer composition may contain polymer components other than hydrogenated block copolymer A and hydrogenated block copolymer B.

[0046] The weight proportion of the total of hydrogenated block copolymer A and hydrogenated block copolymer B in the polymer components constituting the hydrogenated block copolymer composition is not particularly limited, but is preferably 30 to 100% by weight, more preferably 50 to 100% by weight, even more preferably 70 to 100% by weight, even more preferably 90 to 100% by weight, particularly preferably 95 to 100% by weight, and most preferably substantially 100% by weight (i.e., containing no polymer components other than hydrogenated block copolymer A and hydrogenated block copolymer B).

[0047] Examples of polymer components other than hydrogenated block copolymer A and hydrogenated block copolymer B include aromatic vinyl-conjugated diene-aromatic vinyl block copolymers other than hydrogenated block copolymer A and hydrogenated block copolymer B, aromatic vinyl-conjugated diene block copolymers, aromatic vinyl homopolymers, conjugated diene homopolymers, aromatic vinyl-conjugated diene random copolymers, and branched polymers thereof; thermoplastic elastomers such as polyurethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and polyester-based thermoplastic elastomers; thermoplastic resins such as polyolefins, polyvinyl chloride, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, and polyphenylene ether; and the like.

[0048] Furthermore, the hydrogenated block copolymer used in the present invention preferably has an olefin hydrogenation rate in the range of 10 to 100%. For example, when the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, the olefin hydrogenation rate of the polymer components constituting the hydrogenated block copolymer composition is preferably in the range of 10 to 100%. Here, the hydrogenation rate of the olefin refers to the hydrogenation rate of the olefin in all polymer components constituting the hydrogenated block copolymer, specifically, the proportion (mol %) of hydrogenated non-aromatic carbon-carbon double bonds contained in the polymer components before hydrogenation. The hydrogenation rate of the olefin is preferably 20 to 100%, more preferably 30 to 100%, even more preferably 50 to 100%, particularly preferably 70 to 100%, and most preferably 90 to 100%. By setting the hydrogenation rate of the olefin within the above range, it is possible to effectively suppress deformation of the resulting chemical mechanical polishing pad while achieving superior wear resistance. The hydrogenation rate of the olefin can be determined by using deuterated chloroform as a solvent. １ It can be determined by H-NMR spectrum measurement.

[0049] The proportion of aromatic vinyl monomer units in all repeating units of the polymer components constituting the hydrogenated block copolymer used in the present invention (including hydrogenated block copolymer compositions containing hydrogenated block copolymer A and hydrogenated block copolymer B) (hereinafter sometimes referred to as the "total aromatic vinyl monomer unit content") is preferably 20 to 60 wt%, more preferably 25 to 57 wt%, and even more preferably 30 to 54 wt%. By setting the total aromatic vinyl monomer unit content within the above range, the resulting chemical mechanical polishing pad can have better wear resistance. Furthermore, when the hydrogenated block copolymer is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, from the viewpoint of achieving even better wear resistance, the total aromatic vinyl monomer unit content may be 20 to 60 wt%, 25 to 57 wt%, or 30 to 54 wt%. The total aromatic vinyl monomer unit content can be easily adjusted by taking into consideration the aromatic vinyl monomer unit contents of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and other polymer components constituting the hydrogenated block copolymer composition, and adjusting the blending amounts of these components. １ It can be determined by H-NMR measurement.

[0050] In addition, when all polymer components constituting the hydrogenated block copolymer (including the case where the hydrogenated block copolymer composition contains hydrogenated block copolymer A and hydrogenated block copolymer B) are composed only of aromatic vinyl monomer units and conjugated diene monomer units, the polymer components in the hydrogenated block copolymer can be decomposed by ozonolysis and then reduced with lithium aluminum hydride according to the method described in Rubber Chem. Technol., 45, 1295 (1972). This decomposes the conjugated diene monomer unit portions (including hydrogenated portions), allowing only the aromatic vinyl monomer unit portions to be isolated, thereby easily measuring the total aromatic vinyl monomer unit content. The aromatic vinyl monomer unit content and conjugated diene monomer unit content in each block copolymer can be determined by the same method.

[0051] The weight average molecular weight of all the polymer components constituting the hydrogenated block copolymer used in the present invention (including the case where the hydrogenated block copolymer composition contains hydrogenated block copolymer A and hydrogenated block copolymer B) is not particularly limited, but is preferably 30,000 to 400,000, more preferably 35,000 to 100,000, and even more preferably 40,000 to 80,000.

[0052] Furthermore, the molecular weight distribution, which is expressed as the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of all the polymer components constituting the hydrogenated block copolymer (including the case where the hydrogenated block copolymer composition contains hydrogenated block copolymer A and hydrogenated block copolymer B), is not particularly limited, but is preferably 1.01 to 10, more preferably 1.02 to 5, and even more preferably 1.03 to 3.

[0053] (Method for Producing Hydrogenated Block Copolymer) Next, the method for producing the hydrogenated block copolymer used in the present invention is not particularly limited, but the production method will be described using as an example a case where the hydrogenated block copolymer used in the present invention is a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B. The hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B can be produced, for example, by separately producing hydrogenated block copolymer A and hydrogenated block copolymer B according to conventional block copolymer production methods and hydrogenation methods. However, from the viewpoint of being able to produce the hydrogenated block copolymer composition with high productivity, the production method described below is preferred.

[0054] That is, the hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B is preferably produced by a production method including the following steps (1) to (7). (1): A step of polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having active ends. (2): A step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having active ends obtained in the step (1) above and polymerizing the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having active ends. (3): A step of adding an aromatic vinyl monomer to the solution containing the aromatic vinyl-conjugated diene block copolymer having active ends obtained in the step (2) above and polymerizing the aromatic vinyl monomer to obtain a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends. (4): A step of adding a polymerization terminator to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends obtained in the step (3) above in an amount of less than 1 molar equivalent relative to the active ends of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer to deactivate a portion of the active ends of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends to obtain a solution containing block copolymer B'. (5): A step of adding an aromatic vinyl monomer to the solution containing block copolymer B' obtained in the step (4) above to polymerize the aromatic vinyl monomer, thereby obtaining a solution containing block copolymer B' and block copolymer A'. (6): A step of subjecting the solution containing block copolymer B' and block copolymer A' obtained in the step (5) above to a hydrogenation reaction, thereby obtaining a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A. (7): A step of recovering a hydrogenated block copolymer composition from the solution containing hydrogenated block copolymer B and hydrogenated block copolymer A obtained in the step (6) above.

[0055] <Step (1)> In the method for producing this hydrogenated block copolymer composition, first, in step (1), an aromatic vinyl monomer is polymerized in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having an active end.

[0056] The polymerization initiator may be any polymerization initiator known to have anionic polymerization activity for aromatic vinyl monomers and conjugated diene monomers, such as organic alkali metal compounds, organic alkaline earth metal compounds, and organic lanthanoid series rare earth metal compounds.

[0057] As the organic alkali metal compound, an organic lithium compound having one or more lithium atoms in the molecule is particularly preferably used. Specific examples of the organic alkali metal compound include organic monolithium compounds such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, stilbenelithium, dialkylaminolithium, diphenylaminolithium, and ditrimethylsilylaminolithium; organic dilithium compounds such as methylenedilithium, tetramethylenedilithium, hexamethylenedilithium, isoprenyldilithium, and 1,4-dilithio-ethylcyclohexane; and organic trilithium compounds such as 1,3,5-trilithiobenzene. Among these, organic monolithium compounds are particularly preferably used.

[0058] Examples of organic alkaline earth metal compounds include n-butyl magnesium bromide, n-hexyl magnesium bromide, ethoxy calcium, calcium stearate, t-butoxy strontium, ethoxy barium, isopropoxy barium, ethylmercapto barium, t-butoxy barium, phenoxy barium, diethylamino barium, barium stearate, and ethyl barium.

[0059] In addition to the above, a catalyst that forms a homogeneous system in an organic solvent and has living polymerizability, such as a composite catalyst comprising a lanthanoid series rare earth metal compound containing neodymium, samarium, gadolinium, etc. / alkylaluminum / alkylaluminum halide / alkylaluminum hydride, or a metallocene catalyst containing titanium, vanadium, samarium, gadolinium, etc., can also be used.

[0060] The polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited and may be determined depending on the molecular weight of the target block copolymer, but is preferably 0.01 to 20 mmol, more preferably 0.05 to 15 mmol, and even more preferably 0.1 to 10 mmol per 100 g of the total monomers used in the polymerization.

[0061] The solvent used in the polymerization is not particularly limited as long as it is inert to the polymerization initiator, and examples thereof include chain hydrocarbon solvents, cyclic hydrocarbon solvents, and mixed solvents thereof. Examples of chain hydrocarbon solvents include chain alkanes and alkenes having 4 to 6 carbon atoms, such as n-butane, isobutane, 1-butene, isobutylene, trans-2-butene, cis-2-butene, 1-pentene, trans-2-pentene, cis-2-pentene, n-pentane, isopentane, neo-pentane, and n-hexane. Examples of cyclic hydrocarbon solvents include aromatic compounds such as benzene, toluene, and xylene; alicyclic hydrocarbon compounds such as cyclopentane and cyclohexane; and the like. These solvents may be used alone or in combination of two or more.

[0062] The amount of the solvent used is not particularly limited, but is preferably an amount such that the concentration of the total block copolymer in the solution after the polymerization reaction is 5 to 60% by weight, more preferably 10 to 55% by weight, and even more preferably 20 to 50% by weight.

[0063] Furthermore, when producing a hydrogenated block copolymer composition, a Lewis base compound may be added to the reaction system in order to control the structure of each polymer block of each block copolymer. Examples of the Lewis base compound include ethers such as tetrahydrofuran, dibutyl ether, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether; tertiary amines such as tetramethylethylenediamine, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxides such as potassium t-amyl oxide and potassium t-butyl oxide; and phosphines such as triphenylphosphine. These Lewis base compounds may be used alone or in combination of two or more.

[0064] When producing a hydrogenated block copolymer composition, the timing of adding the Lewis base compound is not particularly limited and may be appropriately determined depending on the structure of each target block copolymer. For example, the Lewis base compound may be added in advance before the start of polymerization, or after some of the polymer blocks have been polymerized. Furthermore, the Lewis base compound may be added in advance before the start of polymerization, and then additionally added after some of the polymer blocks have been polymerized.

[0065] The polymerization reaction temperature is preferably 10 to 150° C., more preferably 30 to 130° C., and even more preferably 40 to 90° C. The polymerization time is preferably 48 hours or less, more preferably 0.5 to 10 hours. The polymerization pressure is not particularly limited as long as it is within a pressure range sufficient to maintain the monomer and solvent in a liquid phase at the polymerization temperature.

[0066] By polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator under the above conditions, a solution containing an aromatic vinyl polymer having an active end can be obtained. The aromatic vinyl polymer having an active end obtained in this way in step (1) is a solution containing an aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. ａand aromatic vinyl polymer block Ar1 of hydrogenated block copolymer B ｂ , Ar2 ｂ Either one of (i.e., Ar1 ｂ or Ar2 ｂ Therefore, the polymerization conditions in step (1), including the amount of the aromatic vinyl monomer, may be determined depending on the target weight-average molecular weight of these polymer blocks.

[0067] <Step (2)> Next, in step (2), a conjugated diene monomer is added to the solution containing the aromatic vinyl polymer having active ends obtained in step (1), and the conjugated diene monomer is polymerized to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having active ends.

[0068] According to the step (2), by adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having active ends obtained in the step (1), a conjugated diene polymer chain is formed starting from the active ends, thereby obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having active ends.

[0069] The conjugated diene polymer chain formed in step (2) (the conjugated diene block constituting the aromatic vinyl-conjugated diene block copolymer having an active end obtained in step (2)) is a hydrogenated polymer block HD of the conjugated diene polymer of the hydrogenated block copolymer A. ａ and hydrogenated polymer block HD of the conjugated diene polymer of the hydrogenated block copolymer B ｂ Therefore, the polymerization conditions in step (2), including the amount of the conjugated diene polymer, may be determined depending on the target weight average molecular weight of these polymer blocks, etc. (for example, the polymerization conditions may be determined within the ranges explained in step (1) above).

[0070] <Step (3)> Next, in step (3), an aromatic vinyl monomer is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in step (2), and the aromatic vinyl monomer is polymerized to obtain a solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end.

[0071] According to the step (3), by adding an aromatic vinyl monomer to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the step (2), an aromatic vinyl polymer chain is formed starting from the active end, thereby obtaining a solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end.

[0072] The aromatic vinyl polymer chain formed in step (3) (the aromatic vinyl block constituting the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end obtained in step (3)) is the aromatic vinyl polymer block Ar1 of the hydrogenated block copolymer B. ｂ , Ar2 ｂ One of (i.e., Ar1 ｂ or Ar2 ｂ is a block different from the block formed in step (1), for example, Ar1 ｂ When the compound is formed, Ar2 ｂ Therefore, the polymerization conditions in step (3), including the amount of aromatic vinyl monomer, may be determined depending on the target weight-average molecular weight of the polymer block, etc. (for example, the polymerization conditions may be determined within the ranges explained in step (1) above).

[0073] <Step (4)> Next, in step (4), a polymerization terminator is added to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends obtained in step (3) in an amount of less than 1 molar equivalent relative to the active ends, thereby deactivating a portion of the active ends of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends, thereby obtaining a solution containing block copolymer B'.

[0074] The block copolymer B′ obtained in the step (4) is the block copolymer before hydrogenation for obtaining the hydrogenated block copolymer B.

[0075] The polymerization terminator is not particularly limited as long as it can react with an active terminal to deactivate the active terminal and does not react with another active terminal after reacting with one active terminal, but is preferably a compound containing no halogen atoms, and particularly preferably a polymerization terminator that generates a metal alkoxide, a metal aryloxide, or a metal hydroxide when reacting with an active terminal. Specific examples of the polymerization terminator include water; monohydric alcohols such as methanol and ethanol; monohydric phenols such as phenol and cresol; and the like.

[0076] The amount of the polymerization terminator used may be determined depending on the ratio of hydrogenated block copolymer A and hydrogenated block copolymer B that constitute the hydrogenated block copolymer composition, and is not particularly limited as long as it is an amount that is less than 1 molar equivalent relative to the active terminals of the polymer. However, the amount of the polymerization terminator used is preferably in the range of 0.18 to 0.91 molar equivalents, and more preferably in the range of 0.35 to 0.80 molar equivalents, relative to the active terminals of the polymer.

[0077] As described above, according to step (4), by adding a polymerization terminator to a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends in an amount less than 1 molar equivalent relative to the active ends, the active ends of some of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymers having active ends are deactivated, and the copolymers with deactivated active ends become pre-hydrogenation block copolymer B' for constituting hydrogenated block copolymer B. The remaining portion of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymers having active ends that did not react with the polymerization terminator remains unreacted in the solution while maintaining their active ends.

[0078] <Step (5)> Next, in step (5), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in step (4) above, and the aromatic vinyl monomer is polymerized to obtain a solution containing the block copolymer B' and the block copolymer A'.

[0079] According to step (5), when an aromatic vinyl monomer is added to the solution obtained in step (4), the aromatic vinyl monomer is further polymerized from the aromatic vinyl polymer chain on the side having the active end of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end that has remained unreacted with the polymerization terminator, thereby extending the aromatic vinyl polymer chain and producing block copolymer A'. Note that block copolymer A' is an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer obtained by extending the aromatic vinyl polymer chain, and serves as the block copolymer before hydrogenation for producing hydrogenated block copolymer A.

[0080] In this case, in the step (5), the aromatic vinyl polymer chain to be extended is the aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. ａ Therefore, the polymerization conditions in step (5), including the amount of the aromatic vinyl monomer, are set so as to achieve the above-mentioned aromatic vinyl polymer block Ar2. ａThe polymerization conditions may be determined depending on the target weight average molecular weight, etc. (for example, the polymerization conditions may be determined within the ranges explained in the above step (1)).

[0081] <Step (6)> Next, in step (6), the solution containing block copolymer B′ and block copolymer A′ obtained in step (5) is subjected to a hydrogenation reaction to obtain a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A.

[0082] The method for hydrogenating the solution containing the block copolymer B′ and the block copolymer A′ is not particularly limited, but examples thereof include a method in which the solution containing the block copolymer B′ and the block copolymer A′ is brought into contact with hydrogen in the presence of a hydrogenation catalyst.

[0083] The hydrogenation catalyst is not particularly limited, but examples thereof include supported heterogeneous catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on a carrier such as carbon, silica, alumina, or diatomaceous earth; Ziegler-type catalysts that use an organic salt or acetylacetone salt of Ni, Co, Fe, Cr, or the like and a reducing agent such as organoaluminum; organic complex catalysts such as organometallic compounds of Ru, Rh, etc.; and homogeneous catalysts that use a titanocene compound and a reducing agent such as organolithium, organoaluminum, or organomagnesium; among these, Ziegler-type catalysts are preferred.

[0084] The hydrogenation reaction can be carried out according to the methods disclosed in, for example, Japanese Patent Publication Nos. 42-8704, 43-6636, Japanese Patent Laid-Open Nos. 59-133203 and 60-220147.

[0085] The conditions for the hydrogenation reaction may be selected depending on the hydrogenation rate of the olefin in the polymer components constituting the hydrogenated block copolymer composition, and the hydrogenation reaction temperature is preferably 0 to 200°C, more preferably 30 to 150°C. The hydrogen pressure used in the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and even more preferably 0.3 to 5 MPa, and the hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction may be carried out by a batch process, a continuous process, or a combination thereof.

[0086] <Step (7)> ​​Next, in step (7), the target hydrogenated block copolymer composition is recovered from the solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A obtained in step (6).

[0087] The recovery method may be a conventional method and is not particularly limited. For example, after the reaction is completed, if necessary, a polymerization terminator is added to deactivate the active ends of the polymer having active ends, and if necessary, an additive such as an antioxidant is added, and then the solution is subjected to a known solvent method such as direct drying or steam stripping, thereby recovering the target hydrogenated block copolymer composition. In this case, the polymerization terminator may be any of those described above.

[0088] When the hydrogenated block copolymer composition is recovered as a slurry by steam stripping or the like, it is preferable to dehydrate it using an arbitrary dehydrator such as an extruder-type squeezer to recover the hydrogenated block copolymer composition in the form of crumbs, and then dry the obtained crumbs using an arbitrary dryer such as a band dryer or an expansion extrusion dryer. The hydrogenated block copolymer composition thus obtained may be processed into pellets or the like according to a conventional method before use.

[0089] The solid (pellet-like, crumb-like, etc.) hydrogenated block copolymer composition thus obtained is preferably used after reducing the water content contained in the solid hydrogenated block copolymer composition using a dryer such as a hopper dryer, a hot air circulation tray dryer, a tray vacuum dryer, an agitation vacuum dryer, etc. The drying conditions are not particularly limited as long as the target water content can be achieved, and may be set depending on the amount of water to be reduced and the type of dryer, etc., but are usually set at a drying temperature of 40 to 90°C for a drying time of 1 to 24 hours.

[0090] In addition, when producing a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, a silane modification step may be performed, which can introduce a silane-modified structure. Examples of a silane modification method include reacting the hydrogenated block copolymer composition obtained in step (7) with an unsaturated silane modifier. Preferably, the hydrogenated block copolymer composition obtained in step (7) is reacted with the unsaturated silane modifier and a peroxide by melt-kneading.

[0091] The unsaturated silane modifier is not particularly limited as long as it is a silane compound containing a carbon-carbon unsaturated bond in the molecule, but is preferably a compound (1) represented by the following general formula (1): (In the above general formula (1), R １ ~R ３ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms; R ４ is a hydrocarbon group having a carbon-carbon unsaturated bond.

[0092] In general formula (1), R １ ~R ３ are not particularly limited as long as they are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. １ ~R ３ The alkyl group and alkoxy group represented by R may be linear, branched, or may contain a cyclic structure.２ ~R ４ may be the same or different.

[0093] R １ ~R ３ As R, an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms are preferred, and an alkoxy group having 1 to 6 carbon atoms is more preferred. １ ~R ３ The number of carbon atoms of each of the groups may be independently 0 to 6, preferably 0 to 4, more preferably 0 to 2, and even more preferably 1 (methyl group or methoxy group).

[0094] In general formula (1), R １ ~R ３ At least one of R is preferably an alkoxy group having 1 to 6 carbon atoms, １ ~R ３ It is more preferable that at least two of R are alkoxy groups having 1 to 6 carbon atoms. １ ~R ３ It is more preferable that all of the groups are alkoxy groups having 1 to 6 carbon atoms.

[0095] In general formula (1), R ４ is not particularly limited as long as it is a hydrocarbon group having a carbon-carbon unsaturated bond. ４ R may be linear, branched, or may contain a cyclic structure. ４ Examples of R include vinyl group-containing hydrocarbon groups such as vinyl group, allyl group, 1-methylethenyl group, and 3-butenyl group; and alkynyl groups such as propynyl group, with vinyl group-containing hydrocarbon groups being preferred. ４ The number of carbon atoms in is not particularly limited, but is preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 (vinyl group).

[0096] For example, R ４ is a vinyl group-containing hydrocarbon group, the compound (1) is a compound (2) represented by the following general formula (2):

[0097] In the above general formula (2), R １ ~R ３are the groups described above, and R ５ is a single bond or a divalent hydrocarbon group. ５ The hydrocarbon group as -R in general formula (2) may be linear, branched, or may contain a cyclic structure. ５ -CH=CH ２ represents -R in general formula (1). ４ Corresponds to.

[0098] For example, when compound (2) is used as the unsaturated silane modifier, the hydrogenated block copolymer composition has a group (3) (silane-containing functional group) represented by the following general formula (3) as a modifying group derived from compound (2):

[0099] The unsaturated silane modifier is preferably a compound (4) represented by the following general formula (4).

[0100] In general formula (4), R ６ ~R ８ are each independently an alkyl group having 1 to 6 carbon atoms, and R ９ is a single bond or an alkylene group having 1 to 4 carbon atoms. ６ , -OR ７ , and -OR ８ represents -R in the general formulas (1) to (3), respectively. １ , -R ２ , and -R ３ corresponds to R in general formula (4) ９ represents R in general formulas (2) and (3). ５ Corresponds to.

[0101] R ６ ~R ８ Each of R may be linear, branched, or may contain a cyclic structure. ６ ~R ８ may be the same or different. ６ ~R ８ may each independently have 1 to 6 carbon atoms, preferably 1 to 4, more preferably 1 or 2 (methyl group, ethyl group), and even more preferably 1 (methyl group).

[0102] R ９ R may be linear, branched, or may contain a cyclic structure. ９ The number of carbon atoms may be 0 to 4, preferably 0 to 2, more preferably 0 or 1, and even more preferably 0 (single bond).

[0103] The unsaturated silane modifier may be used alone or in combination of two or more. The amount of the unsaturated silane modifier used is not particularly limited, but is preferably 0.1 to 20 g, more preferably 0.5 to 15 g, and even more preferably 1 to 10 g per 100 g of the polymer component to be modified with the unsaturated silane modifier.

[0104] Examples of peroxides include organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-t-butylperoxyhexane, 2,5-dimethyl-t-butylperoxyhexyne, 1,3-bis(t-butylperoxyisopropyl)benzene, p-chlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, t-butylbenzoate, and 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane. These can be used alone or in combination of two or more.

[0105] The amount of peroxide used is not particularly limited, but is preferably 0.01 to 1 g, more preferably 0.02 to 0.5 g, and even more preferably 0.05 to 0.2 g per 1 g of the unsaturated silane modifier used.

[0106] The method for melt-kneading the hydrogenated block copolymer (including the case of a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B), the unsaturated silane modifier, and the peroxide is not particularly limited, and examples thereof include a method in which the components are heated, melt-mixed using a kneading device such as a roll, a Banbury mixer, a kneader, a Labo Plastomill, a single-screw extruder, or a twin-screw extruder. The conditions for the heated, melt-mixed components are preferably those that can suppress excessive decomposition of the components or the progression of unexpected reactions. For example, the mixing temperature is preferably 180 to 260°C, more preferably 200 to 240°C. The mixing time is preferably 0.5 to 20 minutes, more preferably 1 to 10 minutes.

[0107] According to the above-described method for producing a hydrogenated block copolymer composition, hydrogenated block copolymer A and hydrogenated block copolymer B can be continuously produced in the same reaction vessel, and therefore the target hydrogenated block copolymer composition can be produced with superior productivity compared to the case where each hydrogenated block copolymer is produced separately and then mixed.

[0108] Alternatively, when producing a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B, in addition to the above-described preferred production method (a production method comprising steps (1) to (7)), a production method comprising the following steps (1a) to (6a) is also preferably used. (1a): A step of polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having an active terminal. (2a): A step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active terminal obtained in the above step (1a) and polymerizing the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal. (3a): A step of adding a bifunctional coupling agent to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active terminal obtained in the above step (2a) in an amount such that the total number of functional groups relative to the active terminals is less than 1 molar equivalent, thereby coupling a part of the aromatic vinyl-conjugated diene block copolymer having an active terminal to obtain a solution containing block copolymer B'. (4a): A step of adding an aromatic vinyl monomer to the solution containing block copolymer B' obtained in the above step (3a) and polymerizing the aromatic vinyl monomer to obtain a solution containing block copolymer B' and block copolymer A'. (5a): A step of subjecting the solution containing block copolymer B' and block copolymer A' obtained in the step (4a) above to a hydrogenation reaction to obtain a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A. (6a): A step of recovering a hydrogenated block copolymer composition from the solution containing hydrogenated block copolymer B and hydrogenated block copolymer A obtained in the step (5a) above.

[0109] <Step (1a) and Step (2a)> Step (1a) and step (2a) are similar to the above-described step (1) and step (2), and similar conditions can be employed.

[0110] <Step (3a)> In step (3a), a bifunctional coupling agent is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having active ends obtained in step (2a) in an amount such that the total amount of functional groups relative to the active ends is less than 1 molar equivalent, and a part of the aromatic vinyl-conjugated diene block copolymer having active ends is coupled to obtain a solution containing block copolymer B'.

[0111] The block copolymer B′ obtained in the step (3a) is the block copolymer before hydrogenation for obtaining the hydrogenated block copolymer B.

[0112] The bifunctional coupling agent is not particularly limited as long as it has two functional groups that react with the active terminal, and examples thereof include bifunctional halogenated silanes such as dichlorosilane, monomethyldichlorosilane, and dimethyldichlorosilane; bifunctional halogenated alkanes such as dichloroethane, dibromoethane, methylene chloride, and dibromomethane; and bifunctional tin halides such as dichlorotin, monomethyldichlorotin, dimethyldichlorotin, monoethyldichlorotin, diethyldichlorotin, monobutyldichlorotin, and dibutyldichlorotin.

[0113] The amount of the bifunctional coupling agent used may be determined depending on the ratio of hydrogenated block copolymer A to hydrogenated block copolymer B that constitute the hydrogenated block copolymer composition.

[0114] As described above, according to step (3a), by adding a bifunctional coupling agent to a solution containing an aromatic vinyl-conjugated diene block copolymer having active ends in an amount such that the total amount of functional groups relative to the active ends is less than 1 molar equivalent, a portion of the aromatic vinyl-conjugated diene block copolymer having active ends is coupled to form block copolymer B' before hydrogenation, which is used to form hydrogenated block copolymer B. The remaining portion of the aromatic vinyl-conjugated diene block copolymer having active ends that did not react with the bifunctional coupling agent remains unreacted in the solution, maintaining its active ends.

[0115] <Step (4a)> Next, in step (4a), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in step (3a) above, and the aromatic vinyl monomer is polymerized to obtain a solution containing the block copolymer B' and the block copolymer A'.

[0116] According to step (4a), when an aromatic vinyl monomer is added to the solution obtained in step (3a), the aromatic vinyl monomer is polymerized from the active end of the aromatic vinyl-conjugated diene block copolymer having an active end that remains unreacted with the bifunctional coupling agent, thereby forming an aromatic vinyl polymer chain, thereby obtaining block copolymer A'. Note that block copolymer A' is the block copolymer before hydrogenation for obtaining hydrogenated block copolymer A.

[0117] At this time, the aromatic vinyl polymer chain formed in step (4a) is an aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. ａ Therefore, the polymerization conditions in step (4a), including the amount of the aromatic vinyl monomer, are set so as to achieve the above-mentioned aromatic vinyl polymer block Ar2. ａ The polymerization conditions may be determined depending on the target weight average molecular weight, etc. (for example, the polymerization conditions may be determined within the ranges explained in the above step (1)).

[0118] <Steps (5a) and (6a)> Then, the solution containing block copolymer B' and block copolymer A' obtained in step (4a) can be used to obtain the hydrogenated block copolymer composition used in the present invention through the operations in steps (5a) and (6a) described above. The steps (5a) and (6a) described above are similar to the steps (6) and (7) described above, and similar conditions can be used. If necessary, a modification step can be further carried out in which the hydrogenated block copolymer composition obtained in step (6a) is reacted with an unsaturated silane modifier, thereby introducing a silane-modified structure.

[0119] The hydrogenated block copolymer composition produced as described above may be blended with optional additives, such as antioxidants, at any time. The blending method for the additives is not particularly limited, and examples include a method of heating and melt-mixing the components using a kneading device such as a Banbury mixer, kneader, Labo Plastomill, single-screw extruder, or twin-screw extruder, or a method of preparing a solvent in which the components are dissolved and then removing the solvent by heating or the like. Alternatively, a hydrogenated block copolymer composition may be obtained by preparing a solution containing block copolymer B' before hydrogenation to obtain hydrogenated block copolymer B and block copolymer A' before hydrogenation to obtain hydrogenated block copolymer A, blending the additives therein, and then subjecting the solution to a hydrogenation step. Alternatively, a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A may be prepared.

[0120] Examples of antioxidants include hindered phenol compounds such as pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-p-cresol, and di-t-butyl-4-methylphenol; thiodicarboxylate esters such as dilauryl thiopropionate; and phosphites such as tris(nonylphenyl)phosphite. One type of antioxidant may be used alone, or two or more types may be used in combination. The content of the antioxidant in the hydrogenated block copolymer composition is not particularly limited, but is preferably 10 parts by weight or less, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the hydrogenated block copolymer.

[0121] (Chemical Mechanical Polishing Pad) The chemical mechanical polishing pad of the present invention contains the above-mentioned hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B), and the chemical mechanical polishing pad has grooves or holes.

[0122] When the chemical mechanical polishing pad of the present invention has grooves, the grooves preferably have a depth of 15% or more of the thickness of the chemical mechanical polishing pad, and the groove depth is more preferably 15 to 65%, even more preferably 20 to 60%, and even more preferably 23 to 40%. By providing the chemical mechanical polishing pad with grooves, it is possible to provide excellent wafer transportability, and by setting the groove depth within the above range, it is possible to further improve wafer transportability.

[0123] When the chemical mechanical polishing pad of the present invention has grooves, the groove pattern is not particularly limited, but is preferably a lattice or concentric circle pattern, more preferably a concentric circle pattern.

[0124] The grooves of the chemical mechanical polishing pad of the present invention may be formed by compression molding using a mold having a groove pattern, or by grinding a chemical mechanical polishing pad without grooves. Among these, from the viewpoint of cost, it is preferable to form the grooves by compression molding using a mold having a groove pattern.

[0125] The groove depth of the chemical mechanical polishing pad of the present invention is preferably 15% or more of the thickness of the chemical mechanical polishing pad, and is not particularly limited, but is preferably 0.1 to 2.0 mm, more preferably 0.2 to 1.5 mm, and even more preferably 0.3 to 0.8 mm. The thickness of the chemical mechanical polishing pad itself is not particularly limited, but is preferably 0.5 to 5 mm, more preferably 0.5 to 3 mm, and even more preferably 0.5 to 2 mm.

[0126] The width of the grooves in the chemical mechanical polishing pad of the present invention is not particularly limited, but is preferably 0.05 to 6.0 mm, more preferably 0.15 to 5.5 mm, and even more preferably 0.20 to 5.0 mm.

[0127] When the chemical mechanical polishing pad of the present invention has holes, the holes preferably have a depth of 15% or more of the thickness of the chemical mechanical polishing pad, and the hole depth is more preferably 15 to 65%, even more preferably 20 to 60%, and even more preferably 23 to 40%. The holes may also be through-holes (hole depth 100%). By providing a chemical mechanical polishing pad with holes, excellent wafer transportability can be achieved, and by setting the hole depth within the above range, wafer transportability can be further improved.

[0128] When the chemical mechanical polishing pad of the present invention has holes, the shape of the holes (shape viewed from above) is not particularly limited, but is preferably circular or elliptical, and more preferably circular.

[0129] The method for forming holes in the chemical mechanical polishing pad of the present invention may be compression molding using a mold having a hole pattern, or may be forming by grinding a chemical mechanical polishing pad without holes. Among these, from the viewpoint of cost, it is preferable to form by compression molding using a mold having a hole pattern.

[0130] The pore depth of the chemical mechanical polishing pad of the present invention is preferably 15% or more of the thickness of the chemical mechanical polishing pad, and is not particularly limited, but is more preferably 0.1 to 2.0 mm, even more preferably 0.2 to 1.5 mm, and even more preferably 0.3 to 0.8 mm. The thickness of the chemical mechanical polishing pad itself is also not particularly limited, but is preferably 0.5 to 5 mm, more preferably 0.5 to 3 mm, and even more preferably 0.5 to 2 mm.

[0131] The diameter of the holes in the chemical mechanical polishing pad of the present invention is not particularly limited, but is preferably 0.5 to 4 mm, more preferably 1.0 to 3.0 mm, and even more preferably 1.5 to 2.5 mm.

[0132] The chemical mechanical polishing pad of the present invention preferably has closed pores or interconnected pores, and is not particularly limited thereto, but more preferably has closed pores, and particularly preferably has fine closed pores (for example, micron-order bubbles) dispersed in the chemical mechanical polishing pad. By having closed pores or interconnected pores, when the surface of the chemical mechanical polishing pad is scraped (dressed), the pores are exposed, and the slurry enters the pores, allowing the polishing object to be efficiently polished.

[0133] The method for providing the chemical mechanical polishing pad of the present invention with closed or interconnected pores is not particularly limited, but preferably includes incorporating a physical foaming agent, expanded particles, or crosslinkable hollow particles into a hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B). Specifically, examples include dissolving or dispersing a physical foaming agent in a hydrogenated block copolymer and converting the dissolved or dispersed physical foaming agent into a gas phase, or kneading a hydrogenated block copolymer with expanded particles and then expanding the expanded particles dispersed in the hydrogenated block copolymer. Alternatively, a method can be employed in which a hydrogenated block copolymer is kneaded with crosslinkable hollow particles to introduce closed or interconnected pores by utilizing the voids in the crosslinkable hollow particles. Among these, expanded particles are preferred because they can uniformly distribute fine closed pores in the chemical mechanical polishing pad. Furthermore, from the viewpoint of ease of handling, crosslinkable hollow particles are preferred. In this case, the average pore size of the closed pores or the interconnected pores is not particularly limited depending on the type of expanded particles or crosslinkable hollow particles used, but is preferably 0.1 to 300 μm, more preferably 1 to 200 μm, even more preferably 2 to 190 μm, and particularly preferably 3 to 180 μm.

[0134] Physical blowing agents are liquefied gases or supercritical fluids that are converted into a gas phase by reducing pressure or heating. Examples of physical blowing agents include aliphatic hydrocarbons such as butane, alicyclic hydrocarbons such as cyclobutane, and inorganic gases such as carbon dioxide, nitrogen, and air.

[0135] The expanded beads include those having a low-boiling hydrocarbon compound encapsulated in a shell made of a thermoplastic polymer such as an acrylonitrile copolymer, and when heated, the thermoplastic polymer shell softens and the internal hydrocarbon compound vaporizes, thereby expanding. Commercially available products may be used as the expanded beads, and for example, the Advancel EM series, such as Advancel EM501 manufactured by Sekisui Chemical Co., Ltd., may be used.

[0136] The content of the expanded beads is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight, per 100 parts by weight of the hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B).

[0137] The volume average particle diameter (Dv) of the expanded beads before expansion is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 1 to 60 μm, even more preferably 5 to 50 μm, and particularly preferably 10 to 45 μm. The volume average particle diameter (Dv) of the expanded beads after expansion is not particularly limited, but is preferably 0.2 to 200 μm, more preferably 1 to 180 μm, even more preferably 15 to 170 μm, and particularly preferably 30 to 160 μm.

[0138] The crosslinkable hollow particles include an outer shell and a void surrounded by the outer shell, and the outer shell of the crosslinkable hollow particles is made of a resin consisting of a shell polymer containing a crosslinkable monomer unit.

[0139] The shell polymer is a polymer used to form the shell of the crosslinkable hollow particles and contains a crosslinkable monomer unit. The crosslinkable monomer that forms the crosslinkable monomer unit is a monomer that has two or more polymerizable functional groups and forms a crosslink in the resin by polymerization. As the crosslinkable monomer, a compound having at least one ethylenically unsaturated bond as the polymerizable functional group is generally used.

[0140] The crosslinkable monomers that form the crosslinkable monomer units include crosslinkable hydrocarbon monomers and heteroatom-containing crosslinkable monomers.

[0141] The crosslinkable hydrocarbon monomer is not particularly limited, but examples thereof include bifunctional crosslinkable hydrocarbon monomers such as divinylbenzene, divinyldiphenyl, divinylnaphthalene, dicyclopentadiene, and ethylidenetetracyclododecene, with divinylbenzene being preferred. In addition, crosslinkable hydrocarbon monomers composed of polymers can also be used. Examples include polybutadiene, polyisoprene, styrene-butadiene block copolymers (SBS), and styrene-isoprene block copolymers (SIS).

[0142] The heteroatom-containing crosslinkable monomer is not particularly limited, and examples thereof include bifunctional heteroatom-containing crosslinkable monomers such as diallyl phthalate, allyl (meth)acrylate (meaning allyl acrylate and / or allyl methacrylate; the same applies hereinafter), ethylene glycol di(meth)acrylate, and pentaerythritol di(meth)acrylate; and trifunctional or higher functional heteroatom-containing crosslinkable monomers such as trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and dipentaerythritol poly(meth)acrylate. Among these, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and pentaerythritol tri(meth)acrylate are preferred, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate are more preferred, and ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and pentaerythritol tetramethacrylate are even more preferred.

[0143] As the crosslinkable monomer, a crosslinkable hydrocarbon monomer, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and pentaerythritol tri(meth)acrylate are preferred, divinylbenzene, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate are more preferred, and divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and pentaerythritol tetramethacrylate are even more preferred.

[0144] The crosslinkable monomers can be used alone or in combination of two or more. The shell polymer may contain a bifunctional crosslinkable monomer unit and a trifunctional or higher functional crosslinkable monomer unit. The shell polymer may also contain a crosslinkable hydrocarbon monomer unit and a heteroatom-containing crosslinkable monomer unit.

[0145] The shell polymer may consist essentially of crosslinkable monomer units, or may contain monofunctional monomer units in addition to crosslinkable monomer units.

[0146] The monofunctional monomer forming the monofunctional monomer unit is a monomer having only one polymerizable functional group, and a compound having an ethylenically unsaturated bond as the polymerizable functional group is generally used. Examples of the monofunctional monomer forming the monofunctional monomer unit include monofunctional hydrocarbon monomers and heteroatom-containing monofunctional monomers.

[0147] The monofunctional hydrocarbon monomer is not particularly limited, but examples thereof include aromatic vinyl monomers such as styrene, ethylvinylbenzene, vinyltoluene, α-methylstyrene, p-methylstyrene, and halogenated styrene; monoolefin monomers such as ethylene, propylene, butylene, and 4-methyl-1-pentene; and diene monomers such as butadiene and isoprene. Of these, styrene and ethylvinylbenzene are preferred.

[0148] The heteroatom-containing monofunctional monomer is not particularly limited, and examples thereof include hydrophilic monofunctional monomers; acrylic monovinyl monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and glycidyl (meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate; carboxylic acid vinyl ester monomers such as vinyl acetate; halogenated vinyl monomers such as vinyl chloride; halogenated vinylidene monomers such as vinylidene chloride; vinylpyridine monomers; urethane (meth)acrylate, allyl glycidyl ether, and the like.

[0149] The hydrophilic monofunctional monomer preferably has a solubility in water of 1% by mass or more. The hydrophilic monofunctional monomer is not particularly limited, but examples thereof include monofunctional monomers having a hydrophilic group, such as acid group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, and polyoxyethylene group-containing monomers.

[0150] The term "acid group-containing monomer" refers to a monomer containing an acid group. The acid group referred to here includes both a proton-donating group (Brønsted acid group) and an electron pair-accepting group (Lewis acid group). The acid group-containing monomer is not particularly limited as long as it has an acid group, and examples thereof include carboxyl group-containing monomers and sulfonic acid group-containing monomers. Examples of carboxyl group-containing monomers include ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, and butenetricarboxylic acid; and monoalkyl esters of unsaturated dicarboxylic acids such as monoethyl itaconate, monobutyl fumarate, and monobutyl maleate. Examples of sulfonic acid group-containing monomers include styrenesulfonic acid.

[0151] Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0152] Examples of the amide group-containing monomer include acrylamide and dimethylacrylamide.

[0153] Examples of polyoxyethylene group-containing monomers include methoxypolyethylene glycol (meth)acrylate.

[0154] The monofunctional monomer units may be used either alone or in combination of two or more.

[0155] The content of the crosslinkable monomer unit in the shell polymer is not particularly limited, but is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, even more preferably 60 to 100% by mass, and particularly preferably 80 to 100% by mass. When the content of the crosslinkable monomer is within the above range, a covalent bond network is densely spread throughout the shell, and the occurrence of interconnected pores and shell defects in the shell is suppressed, resulting in excellent mechanical strength.

[0156] The content of the monofunctional monomer unit in the shell polymer is not particularly limited, but from the viewpoint of obtaining the mechanical strength of the crosslinkable hollow particles, it is preferably 0 to 80 mass%, more preferably 0 to 60 mass%, even more preferably 0 to 40 mass%, and particularly preferably 0 to 20 mass%.

[0157] The shell polymer may contain a heteroatom-containing monomer unit. Examples of the heteroatom-containing monomer that forms the heteroatom-containing monomer unit include the heteroatom-containing crosslinkable monomer and the heteroatom-containing monofunctional monomer described above. The content of the heteroatom-containing monomer unit in the shell polymer is not particularly limited, but is preferably 1 to 99% by mass, more preferably 5 to 95% by mass, and even more preferably 10 to 90% by mass.

[0158] The method for producing crosslinkable hollow particles is not particularly limited, but examples include a method in which precursor particles having hollow portions are obtained by polymerizing a suspension containing a crosslinkable monomer, a hydrophobic organic solvent, a polymerization initiator, and an aqueous medium, the hydrophobic solvent is removed from the precursor particles by bubbling, and then the aqueous solvent is removed; and a method in which precursor particles having hollow portions are obtained by polymerizing a suspension containing a crosslinkable monomer, a hydrophobic organic solvent, a polymerization initiator, and an aqueous medium, the precursor particles are separated by solid-liquid separation, and then the hydrophobic solvent in the precursor particles is removed in air.

[0159] The hydrophobic organic solvent is not particularly limited, but a hydrocarbon solvent can be suitably used, and specific examples thereof include saturated hydrocarbon solvents such as butane, pentane, normal hexane, cyclohexane, heptane, and octane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; and relatively volatile solvents such as carbon disulfide and carbon tetrachloride.

[0160] Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, t-butyl peroxide-2-ethylhexanoate, t-butyl peroxydiethyl acetate, t-butyl peroxypivalate, 2,2'-azobis(2,4-dimethylvaleronitrile), and azobisisobutyronitrile.

[0161] The polymerization method is not particularly limited, and for example, a batch method, a semi-continuous method, a continuous method, etc. can be used. The polymerization temperature is preferably 40 to 90°C, more preferably 50 to 80°C. The polymerization reaction time is preferably 1 to 48 hours, more preferably 3 to 24 hours.

[0162] The crosslinkable hollow particles are not limited to those described above, as long as they can form a shell having a three-dimensional crosslinked structure. The shell polymer may be, for example, a phenolic resin, a melamine resin, a urea resin, an unsaturated polyester resin, an epoxy resin, a polyurethane resin, a silicon resin, an alkyd resin, a thermosetting modified polyphenylene ether resin, a thermosetting polyimide resin, a benzoxazine resin, a urea resin, an allyl resin, an aniline resin, a maleimide resin, a bismaleimide triazine resin, a liquid crystalline polyester resin, a vinyl ester resin, an unsaturated polyester resin, a cyanate ester resin, or a polyetherimide resin.

[0163] The crosslinkable hollow particles may have a shell surface treated with a coupling agent. The coupling agent has a functional group capable of bonding with an organic substance and a functional group capable of bonding with an inorganic substance in one molecule, and can increase the affinity between the organic material and the inorganic material. The coupling agent preferably has a functional group in its molecular structure that is capable of crosslinking with the hydrogenated block copolymer.

[0164] The volume average particle size (Dv) of the crosslinkable hollow particles is not particularly limited, but is preferably 0.1 to 100 μm, more preferably 1 to 50 μm, even more preferably 5 to 45 μm, and particularly preferably 2 to 40 μm.

[0165] The particle size distribution (Dv / Dn) (volume average particle diameter (Dv) / number average particle diameter (Dn)) of the crosslinkable hollow particles is not particularly limited, but is preferably 1.02 to 2.00, more preferably 1.04 to 1.60, even more preferably 1.06 to 1.40, particularly preferably 1.06 to 1.30, particularly preferably 1.08 to 1.25, and most preferably 1.10 to 1.20.

[0166] Crosslinkable hollow particles are particles having a shell (outer shell) and a hollow portion (void) surrounded by the shell. The hollow portion is a hollow space clearly distinguishable from the shell of the crosslinkable hollow particle formed by a resin. The crosslinkable hollow particles may have one or more hollow portions, but preferably have only one hollow portion in order to maintain a good balance between high porosity and mechanical strength. The number proportion of crosslinkable hollow particles having only one hollow portion is preferably 90% or more, more preferably 95% or more, and even more preferably more than 95%. One method for determining the number proportion of particles having only one hollow portion among crosslinkable hollow particles is, for example, to observe the cross-section of a sample obtained by curing an epoxy resin in which crosslinkable hollow particles are dispersed using a TEM (transmission electron microscope) and calculate the proportion. The percentage of cross-linkable hollow particles having only one hollow portion among 100 to 150 cross-sections of cross-linkable hollow particles present in a cross-section of a sample observed by TEM can be calculated by calculating the percentage of cross-sections of cross-linkable hollow particles having only one hollow portion. The sample is preferably a thin section prepared by cooling an epoxy resin containing dispersed cross-linkable hollow particles to −80°C to harden the resin and cutting the resin with a microtome. The concentration of cross-linkable hollow particles in the cross-section of the sample is preferably adjusted to a concentration such that 30 to 50 cross-sections of cross-linkable hollow particles can be observed within an area of, for example, 56 μm × 70 μm. The number of hollow portions is determined from an image of the observed cross-section. It is preferable to exclude from the evaluation particle cross-sections that are more than twice the volume average particle diameter, particle cross-sections that are less than 10% of the volume average particle diameter, and cross-sections of cross-linkable hollow particles that do not show any hollow portions. The above method is an example, and the method for determining the proportion of the number of particles having only one hollow portion is not particularly limited.

[0167] Crosslinkable hollow particles usually have a shell that has no interconnected pores or shell defects, and the hollow portion is isolated from the outside of the particle by the shell. However, the shell may have one or more interconnected pores, and the hollow portion may communicate with the outside of the particle via the interconnected pores. Furthermore, one crosslinkable hollow particle may have two or more hollow portions. In this case, the two or more hollow portions may exist independently, or the two or more hollow portions may be connected to each other.

[0168] The hollow portion may be filled with a gas such as air, or may contain a solvent.

[0169] The shape of the crosslinkable hollow particles is not particularly limited as long as a hollow portion is formed inside. The external shape of the crosslinkable hollow particles is not particularly limited, but a spherical shape is preferred from the viewpoint of ease of production. The crosslinkable hollow particles may contain a small amount of particles with low circularity due to cracking or deformation as impurities, but from the viewpoint of further enhancing the effects of the present disclosure, the proportion of particles with a circularity of 0.85 or less in 100% by mass of the crosslinkable hollow particles is preferably less than 15% by mass, more preferably less than 10% by mass, and even more preferably less than 8% by mass.

[0170] The external shape of the crosslinkable hollow particles can be confirmed, for example, by observing the particles with an SEM or a TEM, and the internal shape of the crosslinkable hollow particles can be confirmed, for example, by observing the cross section of the particles with an SEM or a TEM.

[0171] The true density of the crosslinkable hollow particles is not particularly limited, but is preferably 0.95 to 1.4 g / cm ３ is preferably 1.0 to 1.3 g / cm ３ It is more preferable that:

[0172] The true density of the crosslinkable hollow particles means the density of only the shell portion of the crosslinkable hollow particles. Specifically, the true density of the crosslinkable hollow particles is measured by the following method. The crosslinkable hollow particles are crushed in advance, and then crushed into a 100 cm3 container. ３Approximately 10 g of crushed pieces of the crosslinkable hollow particles is filled into a measuring flask, and the mass of the crushed pieces is accurately weighed. Next, in the same manner as in the measurement of the apparent density, isopropanol is added to the measuring flask, and the mass of the isopropanol is accurately weighed. The true density (g / cm) of the crosslinkable hollow particles is calculated based on the following formula (I): ３ ) is calculated. ３ ) = [mass of crushed pieces of crosslinkable hollow particles] ÷ (100 - [mass of isopropanol] ÷ [density of isopropanol at measurement temperature]) (I)

[0173] The porosity of the crosslinkable hollow particles is preferably 40 to 95%, more preferably 50 to 90%, even more preferably 55 to 88%, particularly preferably 60 to 85%, and most preferably 65 to 80%.

[0174] The porosity of the crosslinkable hollow particles is determined by the apparent density D １ and true density D ０ The apparent density D １ corresponds to the density of the entire crosslinkable hollow particle when the hollow portion is considered to be a part of the crosslinkable hollow particle. Furthermore, when the hollow portion of the crosslinkable hollow particle contains components other than the components constituting the shell (shell polymer, etc.), it is considered that most of the components other than the components constituting the shell are derived from residual solvents, and therefore the density of the components other than the components constituting the shell is the true density D of the crosslinkable hollow particle. ０ Specifically, the apparent density D is calculated by using the mass of the crosslinkable hollow particles including the mass of components other than the components constituting the shell. １ Then, the apparent density D １ The porosity of the crosslinkable hollow particles is calculated using the formula:

[0175] Apparent density D of crosslinkable hollow particles １ The measurement method is as follows: First, a volume of 100 cm ３ About 30 cm ３The volumetric flask filled with the crosslinkable hollow particles is then filled with isopropanol up to the marked line, taking care not to introduce air bubbles. The mass of the isopropanol added to the volumetric flask is then accurately weighed, and the apparent density D of the crosslinkable hollow particles is calculated based on the following formula (II): １ (g / cm ３ ) is calculated. １ (g / cm ３ ) = [mass of crosslinkable hollow particles] ÷ (100 - [mass of isopropanol] ÷ [density of isopropanol at measurement temperature]) (II)

[0176] The porosity (%) of the crosslinkable hollow particles is calculated by multiplying the apparent density D １ and true density D ０ The porosity of the crosslinkable hollow particles (%) is calculated from the above formula (III): 100−[apparent density D of the crosslinkable hollow particles] １ ]÷[true density D of crosslinkable hollow particles ０ ]×100 (III)

[0177] The content of the crosslinkable hollow particles is not particularly limited, but is preferably 0 to 40 parts by weight, more preferably 5 to 30 parts by weight, and even more preferably 10 to 20 parts by weight, relative to 100 parts by weight of the hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B).

[0178] Furthermore, in addition to the hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B), the physical foaming agent, the expanded particles, or the crosslinkable hollow particles, the chemical mechanical polishing pad of the present invention may further contain, as necessary, various compounding agents such as processing aids, fillers, pigments, antistatic agents, flame retardants, water repellents, waterproofing agents, electrical conductivity imparting agents, thermal conductivity imparting agents, electromagnetic wave shielding agents, fluorescent agents, antibacterial agents, light stabilizers, ultraviolet absorbers, dyes, and lubricants.

[0179] The method for producing the chemical mechanical polishing pad of the present invention is not particularly limited, but it can be produced, for example, by compression molding the above-mentioned hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B). In this case, it is preferable to adopt a method of compression molding using a mold having a groove pattern with a depth of 15% or more of the thickness of the chemical mechanical polishing pad, using a compression molding machine.

[0180] Furthermore, when the chemical mechanical polishing pad of the present invention is made to have closed pores or continuous pores by using expanded particles, a method can be used in which the above-mentioned hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B) and the expanded particles are kneaded at a temperature below the expansion initiation temperature of the expanded particles, and the resulting kneaded product is compression molded at a temperature equal to or higher than the expansion initiation temperature of the expanded particles. The temperature during compression molding can be selected depending on the expansion initiation temperature of the expanded particles used, and is not particularly limited, but is preferably 120 to 280 ° C, more preferably 150 to 250 ° C. In this case, it is also preferable to use a method of compression molding using a mold having a groove pattern with a depth of 15% or more relative to the thickness of the chemical mechanical polishing pad, using a compression molding machine.

[0181] Alternatively, when the chemical mechanical polishing pad of the present invention is to be provided with closed or interconnected pores by using crosslinkable hollow particles, a method can be employed in which the above-described hydrogenated block copolymer (including a hydrogenated block copolymer composition containing hydrogenated block copolymer A and hydrogenated block copolymer B) is kneaded with the crosslinkable hollow particles, and the resulting kneaded product is compression-molded. The temperature during compression molding is not particularly limited, but is preferably 120 to 280°C, more preferably 150 to 250°C. In this case, it is also preferable to employ a method of compression molding using a mold having a groove pattern with a depth of 15% or more relative to the thickness of the chemical mechanical polishing pad, using a compression molding machine.

[0182] The specific gravity (apparent density) of the chemical mechanical polishing pad of the present invention is not particularly limited, but is preferably 0.5 to 1 g / cm ３ is preferably 0.7 to 0.96 g / cm ３ It is more preferable that:

[0183] The porosity of the chemical mechanical polishing pad of the present invention is not particularly limited, but is preferably 0 to 50% by volume, and more preferably 0 to 25% by volume.

[0184] <Chemical Mechanical Polishing Apparatus> The chemical mechanical polishing pad of the present invention can be suitably used, for example, as a polishing pad for chemically polishing silicon wafers. FIG. 1 is a schematic diagram of a chemical mechanical polishing apparatus 10 according to one embodiment of the present invention. As shown in FIG. 1, the chemical mechanical polishing apparatus 10 includes a platen 20 and a chemical mechanical polishing pad 12 mounted thereon. A wafer 14 to be polished, which has an oxide film thereon, is fixed by a retainer ring 16 and pressed against the chemical mechanical polishing pad 12 by a polishing head 18. The chemical mechanical polishing apparatus 10 also includes a dresser 22 for dressing the surface of the chemical mechanical polishing pad 12 and a slurry supply means 26 for supplying a slurry 24. In this embodiment, the chemical mechanical polishing pad of the present invention described above is used as the chemical mechanical polishing pad 12.

[0185] In the chemical mechanical polishing apparatus 10, a slurry supply means 26 supplies a slurry 24 to the surface of the chemical mechanical polishing pad 12 while the platen 20 and the polishing head 18 are rotated in the same direction at the same or different rotational speeds, so that the chemical mechanical polishing pad 12 and the oxide film-coated wafer 14 rotate relative to each other while being pressed against each other due to the rotation of the platen 20 and the polishing head 18, thereby polishing the oxide film-coated wafer 14. In addition, in the chemical mechanical polishing apparatus 10, when the chemical mechanical polishing pad 12 is rotated, the dresser 22 scrapes (dresses) the surface of the chemical mechanical polishing pad 12, thereby regenerating the polishing surface and thereby maintaining polishing performance.

[0186] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Note that "parts" and "%" are by weight unless otherwise specified. The test methods used in these examples and comparative examples are as follows.

[0187] [Weight-Average Molecular Weight and Molecular Weight Distribution of Hydrogenated Block Copolymer Composition] The weight-average molecular weight and molecular weight distribution of the hydrogenated block copolymer composition were determined in terms of standard polystyrene based on a chart obtained by high-performance liquid chromatography using tetrahydrofuran as a carrier at a flow rate of 0.35 ml / min to obtain a polystyrene-equivalent molecular weight. The analyzer used was a Tosoh HLC8320, and the column consisted of three connected Shodex (registered trademark) KF-404HQ columns manufactured by Showa Denko K.K. (column temperature: 40°C). The detectors used were a differential refractometer and an ultraviolet detector. Molecular weight calibration was performed at 12 points using standard polystyrenes (5 to 3 million) manufactured by Polymer Laboratory.

[0188] [Weight Ratio of Each Block Copolymer in the Hydrogenated Block Copolymer Composition] The weight ratio of each block copolymer in the hydrogenated block copolymer composition was determined from the area ratio of the peak corresponding to each block copolymer in the chart obtained by the above-mentioned high performance liquid chromatography.

[0189] [Weight-Average Molecular Weight of Styrene Polymer Block of Hydrogenated Block Copolymer] First, according to the method described in Rubber Chem. Technol., 45, 1295 (1972), the hydrogenated block copolymer was reacted with ozone and reduced with lithium aluminum hydride to decompose the isoprene polymer block of the hydrogenated block copolymer. Specifically, the decomposition of the isoprene polymer block was carried out as follows. That is, 300 mg of a sample was dissolved in a reaction vessel containing 100 ml of dichloromethane treated with molecular sieves. The reaction vessel was then placed in a cooling bath and cooled to −25°C. Ozone generated by an ozone generator was then introduced into the reaction vessel while oxygen was flowing into the reaction vessel at a flow rate of 170 ml / min. Thirty minutes after the start of the reaction, the completion of the reaction was confirmed by introducing the gas flowing out of the reaction vessel into an aqueous potassium iodide solution. Next, 50 ml of diethyl ether and 470 mg of lithium aluminum hydride were placed in a separate reaction vessel purged with nitrogen. While cooling the reaction vessel with ice water, the solution reacted with ozone was slowly added dropwise to the reaction vessel. The reaction vessel was then placed in a water bath, gradually heated, and refluxed at 40°C for 30 minutes. Subsequently, while stirring the solution, dilute hydrochloric acid was added dropwise to the reaction vessel in small amounts until hydrogen generation was almost completely eliminated. After the reaction, the solid product formed in the solution was filtered, and the solid product was extracted with 100 ml of diethyl ether for 10 minutes. This extract and the filtrate were combined, and the solvent was distilled off to obtain a solid sample. The weight-average molecular weight of the sample thus obtained was measured according to the above-mentioned method for measuring the weight-average molecular weight of a hydrogenated block copolymer composition, and the resulting value was taken as the weight-average molecular weight of the styrene polymer block.

[0190] [Weight Average Molecular Weight of Hydrogenated Isoprene Polymer Block of Hydrogenated Block Copolymer] The weight average molecular weight of the corresponding styrene polymer block was subtracted from the weight average molecular weight of the hydrogenated block copolymer determined as described above, and the weight average molecular weight of the hydrogenated isoprene polymer block was determined based on the calculated value.

[0191]

[0043] The styrene unit content of the hydrogenated block copolymer was determined based on the ratio of the detection intensities of the differential refractometer and the ultraviolet detector in the high performance liquid chromatography measurement. Copolymers having different styrene unit contents were prepared in advance, and a calibration curve was created using these copolymers.

[0192] [Content of styrene units in the entire hydrogenated block copolymer composition] The content of styrene units in the entire hydrogenated block copolymer composition was measured using deuterated chloroform as a solvent. １ It was determined based on H-NMR measurement.

[0193] [Vinyl Bond Content of (Hydrogenated) Isoprene Polymer Block] The vinyl bond content of the (hydrogenated) isoprene polymer block was measured using deuterated chloroform as a solvent. １ It was determined based on H-NMR measurement.

[0194] [Olefin Hydrogenation Ratio (Mole %) of Hydrogenated Block Copolymer Composition] Deuterated chloroform was used as the solvent. １ The olefin amount was determined for each of the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation by H-NMR spectrum measurement, and the olefin hydrogenation rate (mol %) of the hydrogenated block copolymer composition was calculated based on the difference in the olefin amount before and after hydrogenation. １ In the H-NMR spectrum measurement, deuterated chloroform was used as the solvent, and a JMN-AL series AL400 (manufactured by JEOL) was used as the NMR measurement apparatus. In the present examples and comparative examples, both the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation contained only isoprene units as olefin-derived monomer units, and therefore the hydrogenation rate of the isoprene units was determined in the measurement, and this was taken as the olefin hydrogenation rate.

[0195] [Shore A Hardness of Hydrogenated Block Copolymer Composition] According to ISO 7619, the Shore A hardness of the hydrogenated block copolymer composition was determined.

[0196] [Specific gravity and porosity of chemical mechanical polishing pad] According to JIS K 7311:1995 (underwater displacement method), measure the specific gravity (apparent density) of the chemical mechanical polishing pad obtained in Example and Comparative Example.In addition, measure the specific gravity (true density) of the hydrogenated block copolymer composition used for manufacturing chemical mechanical polishing pad in the same way, and calculate the porosity of chemical mechanical polishing pad from the specific gravity (apparent density) of chemical mechanical polishing pad and the specific gravity (true density) of hydrogenated block copolymer composition.In addition, in Comparative Example 2, use the specific gravity (true density) of general urethane rubber to carry out measurement.

[0197] [Polishing Test] A polishing test was performed using the chemical mechanical polishing pads obtained in the Examples and Comparative Examples with a chemical mechanical polishing apparatus 10 shown in Fig. 1. Specifically, using the chemical mechanical polishing apparatus 10 shown in Fig. 1, the chemical mechanical polishing pads obtained in the Examples and Comparative Examples were attached to a surface plate (platen) 20 with an adhesive, and a 4-inch silicon wafer with an oxide film was used as the silicon wafer 14 to be polished. The 4-inch silicon wafer with an oxide film was polished while dropping silica slurry 14 at a dropping speed of 100 cc / min under the following conditions: Rotation speed of platen 20: 60 rpm, Rotation speed of polishing head 18: 61 rpm, Pressing pressure of silicon wafer 14: 3.0 psi, Pressing pressure of retainer ring 16: 3.6 psi

[0198] In the polishing test, the wafer polishing rate and wafer transportability of the chemical mechanical polishing pad were evaluated as follows. Wafer Polishing Rate: A 4-inch silicon wafer with an oxide film was measured before and after polishing using an interference film thickness meter (manufactured by Ocean Photonics, product name "Reflectance Measurement Fiber Multichannel Spectroscopic System SR4-RF"), and the difference in oxide film thickness before and after polishing was calculated to determine the wafer polishing rate. Wafer Transportability of the Chemical Mechanical Polishing Pad: After polishing, the adhesion between the silicon wafer 14 and the chemical mechanical polishing pad was visually observed when the polishing head 18 was raised, and evaluated according to the following criteria: ◯: The silicon wafer was raised while still attached to the polishing head ×: The silicon wafer remained on the chemical mechanical polishing pad Furthermore, the surface of the chemical mechanical polishing pad 12 was scraped (dressed) using the dresser 22, and the wear resistance of the chemical mechanical polishing pad 12 was evaluated. Wear resistance of chemical mechanical polishing pad The thickness of the chemical mechanical polishing pad 12 was measured using a depth gauge (manufactured by Mitutoyo Corporation, product name "Digimatic Depth Gauge"), and the difference in thickness before and after dressing using the dresser 22 was calculated to evaluate the wear resistance of the chemical mechanical polishing pad.

[0199] [Production Example 1] (1) Production of a block copolymer composition before hydrogenation 56.6 kg of cyclohexane, 387 mmol of dibutyl ether, and 1.23 kg of styrene were added to a pressure reactor. While stirring the entire contents at 40°C, 208 mmol of n-butyllithium (1.6 M solution) was added. After the addition was completed, the temperature was raised to 50°C and a polymerization reaction was carried out for 1 hour (first stage of polymerization). The polymerization conversion of styrene at this time was 100% by weight.

[0200] Subsequently, 5.00 kg of isoprene was continuously added to the reactor over 1 hour while controlling the temperature to maintain a temperature of 50 to 60°C. After the addition of isoprene was completed, the polymerization reaction was continued for another 1 hour (second-stage polymerization). The polymerization conversion of isoprene at this time was 100%.

[0201] Next, 1.23 kg of styrene was continuously added over 1 hour while controlling the temperature to maintain it at 50 to 60°C. After the addition of styrene was completed, the polymerization reaction was continued for another 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having active terminals (third polymerization stage). The polymerization conversion of styrene at this time was 100%.

[0202] Next, 145 mmol of methanol was added as a polymerization terminator and mixed to deactivate some of the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, thereby obtaining a solution containing a styrene-isoprene-styrene triblock copolymer that would become block copolymer B' for obtaining hydrogenated block copolymer B.

[0203] Thereafter, 2.53 kg of styrene was continuously added over 1 hour while continuing to control the temperature to maintain it at 50 to 60°C. After the addition of styrene was completed, the polymerization reaction was continued for another 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having active ends, which would become block copolymer A' for obtaining hydrogenated block copolymer A (fourth polymerization stage). The polymerization conversion of styrene at this time was 100%.

[0204] Finally, 271 mmol of methanol was added as a polymerization terminator and mixed to deactivate all of the active ends of the styrene-isoprene-styrene triblock copolymer, thereby completing the polymerization reaction. The amounts of each reagent used in the reaction are summarized in Table 1.

[0205] (2) Hydrogenation Reaction of Block Copolymer Composition Before Hydrogenation A solution containing the block copolymer composition before hydrogenation obtained above was subjected to a hydrogenation reaction to obtain a solution containing a hydrogenated block copolymer composition. The hydrogenation reaction was carried out by adding Ni(AcAc) ２The -TIBAL catalyst was added in a proportion of 0.5% by weight based on the block copolymer composition before hydrogenation, and the reaction was carried out under conditions of a hydrogen pressure of 3 MPa, a reaction temperature of 80° C., and a reaction time of 3 hours.

[0206] A portion of the solution containing hydrogenated block copolymer composition 1 thus obtained was removed, and the weight average molecular weight of each block copolymer contained in the composition, the weight ratio of each block copolymer in the composition, the weight average molecular weight of the styrene polymer block of each block copolymer, the weight average molecular weight of the isoprene polymer block of each block copolymer, the styrene unit content of each block copolymer, the styrene unit content of the block copolymer composition (as a whole), the vinyl bond content of the isoprene polymer block of each block copolymer, the olefin hydrogenation rate, the density of the block copolymer composition (as a whole), and the Shore A hardness (-) of the block copolymer composition (as a whole) were determined. These values ​​are summarized in Table 2.

[0207] (3) Recovery of Hydrogenated Block Copolymer Composition 1 To 100 parts of the solution containing the hydrogenated block copolymer composition obtained as described above, 0.3 parts of 2,6-di-t-butyl-p-cresol was added as an antioxidant and mixed, and the mixed solution was added dropwise in small amounts to warm water heated to 85 to 95°C to volatilize the solvent and obtain a precipitate. The obtained precipitate was pulverized and dried with hot air at 85°C to recover crumb-like hydrogenated block copolymer composition 1.

[0208] Production Example 2 Hydrogenated block copolymer composition 2 was obtained in the same manner as in Production Example 1, except that the amounts of each reagent (dibutyl ether, n-butyllithium, styrene, isoprene, and methanol) used in the reaction were changed as shown in Table 1. Measurements and evaluations were carried out in the same manner as in Production Example 1. The results are shown in Table 2.

[0209] [Production Example 3] Crosslinkable hollow particles were produced by the following method: (A) Mixture Preparation Step First, the following materials were mixed to prepare an oil phase. Divinylbenzene (crosslinkable hydrocarbon monomer) 22.5 parts Ethylvinylbenzene (monofunctional hydrocarbon monomer) 0.9 parts Ethylene glycol dimethacrylate (heteroatom-containing crosslinkable monomer) 7.8 parts Pentaerythritol tetraacrylate (heteroatom-containing crosslinkable monomer) 7.8 parts 2,2'-Azobis(2,4-dimethylvaleronitrile) (oil-soluble polymerization initiator) 1.04 parts Hydrophobic solvent: Heptane 60.8 parts Next, in a stirring vessel, an aqueous solution obtained by dissolving 7.83 parts of magnesium chloride (a water-soluble polyvalent metal salt) in 225 parts of ion-exchanged water was gradually added with stirring to an aqueous solution obtained by dissolving 5.49 parts of sodium hydroxide (an alkali metal hydroxide) in 55 parts of ion-exchanged water, to prepare a magnesium hydroxide colloid (a poorly water-soluble metal hydroxide colloid) dispersion as an aqueous phase. The resulting aqueous phase and oil phase were mixed to prepare a mixed liquid. (B) Suspension Step: Next, the mixture obtained in the mixture preparation step was suspended using an in-line emulsifier / disperser to prepare a suspension in which monomer droplets encapsulating a hydrophobic solvent were dispersed in water. (C) Polymerization Step: The suspension obtained in the suspension step was heated from 40°C to 65°C in a nitrogen atmosphere and stirred at 65°C for 24 hours to carry out a polymerization reaction. This polymerization reaction resulted in a precursor composition, which was a slurry in which precursor particles encapsulating a hydrophobic solvent were dispersed in water. (D) Solvent Removal Step: The hydrophobic solvent encapsulated in the precursor particles was removed using an in-liquid solvent removal method to obtain a crosslinkable hollow particle slurry containing crosslinkable hollow particles and water. Specifically, nitrogen gas was bubbled through the bottom of the container into the precursor composition obtained in the polymerization step for 12 hours at 90°C to replace the hydrophobic solvent encapsulated in the precursor particles with nitrogen gas. The amount of nitrogen gas bubbling per minute was the same as the volume of the precursor composition obtained in the polymerization step. (E) Washing step and solid-liquid separation step The crosslinkable hollow particle slurry obtained in the solvent removal step was washed with dilute sulfuric acid (25°C, 10 minutes) to adjust the pH to 5.5 or less.Next, after separating the water by filtration, 200 parts of fresh ion-exchanged water was added to re-slurry the mixture. The water washing process (washing, filtration, dehydration) was repeated several times at room temperature (25°C), and the mixture was filtered to obtain a solid. (F) Moisture Removal Step: The solid obtained in the solid-liquid separation step was heated in a vacuum dryer at 40°C for 12 hours to remove moisture from the surface of the crosslinkable hollow particles, thereby obtaining crosslinkable hollow particles. The monomer composition of the shell polymer in the obtained crosslinkable hollow particles was generally consistent with the composition of the polymerizable monomer used in the polymerization. Furthermore, the true density, porosity, volume average particle size (Dv), and particle size distribution (Dv / Dn) of the obtained crosslinkable hollow particles were measured, and the true density was 1.090 g / cm. ３ The porosity was 71%, the volume average particle size (Dv) was 7.10 μm, and the particle size distribution (Dv / Dn) was 1.21.

[0210] Example 1 100 parts of the hydrogenated block copolymer composition 1 obtained in Production Example 1 and 1.5 parts of expanded particles (manufactured by Sekisui Chemical Co., Ltd., product name "Advancell EM501", expanded particles in which a thermoplastic polymer shell made of an acrylonitrile copolymer encapsulates low-boiling hydrocarbons) were fed into a kneader and kneaded at a temperature of 120 ° C. to obtain a kneaded product. The kneaded product obtained was compressed at a temperature of 220 ° C. and a pressure of 6 MPa for 3 minutes using a mold having a concentric groove inverse pattern with a groove depth of 0.4 mm (a mold capable of forming a concentric groove pattern with a groove depth of 0.4 mm) and a compression molding machine, and then cooled to 80 ° C. After the mold was opened, the expanded particles were expanded and molded to form a disc-shaped chemical mechanical polishing pad having a diameter of 38 cm and a thickness of 1.3 mm (having a groove depth of 30% of the pad thickness) with a concentric groove pattern with a groove depth of 0.4 mm and a width of 0.25 mm. The resulting chemical mechanical polishing pad was evaluated according to the above method, and the results are shown in Table 3.

[0211] A chemical mechanical polishing pad was prepared in the same manner as in Example 1, except that hydrogenated block copolymer composition 2 was used instead of hydrogenated block copolymer composition 1 and the amount of foamed particles used in preparing the chemical mechanical polishing pad was changed from 1.5 parts to 1.2 parts, and measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 3.

[0212] [Example 3] A chemical mechanical polishing pad was produced in the same manner as in Example 1, except that 16 parts of the crosslinkable hollow particles obtained in Production Example 3 were used instead of the expanded particles when producing the chemical mechanical polishing pad, and measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 3.

[0213] [Comparative Example 1] A chemical mechanical polishing pad without a groove pattern was prepared in the same manner as in Example 1, except that a mold without a concentric groove pattern was used as the molding mold, and a polishing test was carried out in the same manner as in Example 1. The results are shown in Table 3.

[0214] Comparative Example 2 A chemical mechanical polishing pad made of cross-linked urethane and having a concentric groove pattern with a groove depth of 0.4 mm (manufactured by Nitta DuPont, product name "IC1400") was used to carry out a polishing test in the same manner as in Example 1. The results are shown in Table 3.

[0215]

[0216]

[0217]

[0218] As shown in Table 3, the chemical mechanical polishing pads of Examples 1 to 3, which contain a hydrogenated block copolymer and have grooves, achieved a sufficient polishing rate while keeping the amount of wear when dressed by the dresser 22 low, providing excellent wear resistance and also excellent wafer transportability.

Claims

1. A chemical mechanical polishing pad containing a hydrogenated block copolymer having an aromatic vinyl polymer block and a hydrogenated polymer block of a conjugated diene polymer, wherein the chemical mechanical polishing pad has grooves or holes.

2. The chemical mechanical polishing pad according to claim 1, wherein the hydrogenated block copolymer comprises a hydrogenated block copolymer A represented by the following general formula (A) or a hydrogenated block copolymer B represented by the following general formula (B): ａ -HD ａ -Ar2 ａ (A) (In the above general formula (A), Ar1 ａ and Ar2 ａ is an aromatic vinyl polymer block, and HD ａ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ａ Weight average molecular weight (Mw(Ar1 ａ )) with respect to Ar2 ａ Weight average molecular weight (Mw(Ar2 ａ )) ratio (Mw(Ar2 ａ ) / Mw(Ar1 ａ )) is 3.0 to 20. ) Ar1 ｂ -HD ｂ -Ar2 ｂ (B) (In the above general formula (B), Ar1 ｂ and Ar2 ｂ is an aromatic vinyl polymer block, and HD ｂ is a hydrogenated polymer block of a conjugated diene polymer, and Ar1 ｂ Weight average molecular weight (Mw(Ar1 ｂ )) with respect to Ar2 ｂ Weight average molecular weight (Mw(Ar2 ｂ )) ratio (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ )) is 0.95 to 1.

05.

3. The chemical mechanical polishing pad according to claim 2, wherein the hydrogenated block copolymers contain both the hydrogenated block copolymer A and the hydrogenated block copolymer B.

4. In the general formula (A) and the general formula (B), Ar1 ａ , Ar1 ｂ , and Ar2 ｂ The weight average molecular weight of each of the above ranges from 2,000 to 40,000, and HD ａ and HD ｂ 4. The chemical mechanical polishing pad according to claim 2, wherein the weight average molecular weight of each of the above is in the range of 10,000 to 300,000.

5. The chemical mechanical polishing pad according to claim 3 or 4, wherein the weight ratio (A / B) of said hydrogenated block copolymer A to said hydrogenated block copolymer B is 10 / 90 to 80 / 20.

6. The chemical mechanical polishing pad according to any one of claims 1 to 5, wherein the proportion of the aromatic vinyl monomer units in all repeating units of the hydrogenated block copolymer is 20 to 60 wt %.

7. The chemical mechanical polishing pad according to any one of claims 1 to 6, further comprising expanded particles or crosslinked hollow particles.

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