JP2018051745A - Polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad which is excellent in heat resistance, suppresses lowering of hardness by frictional heat at the time of polishing and is excellent in dressing properties.SOLUTION: A polishing pad has a polishing layer formed of a polyurethane resin, where the polishing layer is formed by curing a polyurethane resin curable composition containing a polyisocyanate compound and a curing agent, the curing agent contains an amine-based curing agent and a polyol curing agent having a bisphenol A structure represented by formula (I), a molar ratio of the amine-based curing agent to the polyol curing agent having the bisphenol A structure is 90:10 to 70:30, and a ratio ((molar number of NH+molar number of OH)/molar number of NCO) of the total of a molar number of NH of the amine-based curing agent and a molar number of OH of the polyol curing agent having the bisphenol A structure to the molar number of NCO of the polyisocyanate compound is 0.7 to 1.1. In formula (I), R is an alkylene group having 2 or 3 carbon atoms; and n and m are each independently an integer of 1 to 7.SELECTED DRAWING: None

Description

  The present invention relates to a polishing sheet or a polishing pad for polishing materials that require high surface flatness such as optical materials, semiconductor substrates, semiconductor wafers, hard disk substrates, liquid crystal glass substrates, and semiconductor devices. The present invention is particularly suitable for polishing a device in which an oxide layer, a metal layer or the like is formed on a semiconductor wafer.

  Optical materials, semiconductor substrates, semiconductor wafers, hard disk substrates, liquid crystal glass substrates, and semiconductor devices are required to have very precise flatness. In addition, various materials having different hardnesses such as metal, organic and inorganic insulating materials are exposed on the surface of the semiconductor material. In order to polish the surface of such a material flatly, it is necessary that the surface of the polishing pad also maintain uniform rigidity. If the stiffness of the surface of the polishing pad changes during the polishing operation, the desired flatness cannot be achieved.

  For example, considerable polishing scraps are generated at the end of one polishing operation from the start of polishing to the replacement of the polishing pad and the polishing liquid. Since the clogging of the opening due to accumulation of polishing debris, the retention of slurry deteriorates and frictional heat is generated, the temperature of the surface of the material to be polished is from the initial to the end during one polishing operation And changes over a wide temperature range including 20 ° C to 70 ° C. Moreover, the chemical action (corrosion of the surface of a non-polishing object) becomes strong with the temperature rise in the polishing liquid used for chemical mechanical polishing. Therefore, precise flatness cannot be achieved due to the surface of the polishing pad whose rigidity has been locally lowered due to temperature changes of the workpiece or polishing liquid, and only metal parts are preferentially polished (dishing). It tends to occur.

  Also, accumulation of polishing waste is usually eliminated by roughening (dressing) the surface of the polishing pad using a dresser. If this dressing takes too much time, that is, if the dressing speed is low, the polishing efficiency is deteriorated.

  Many hard polishing pads are obtained by using urethane prepolymer, which is a reaction product of polyol component and isocyanate component, and adding and mixing curing agents (chain extenders) such as diamines or diols, foaming agents, catalysts, etc. Manufactured by a prepolymer method for curing a polyurethane composition. In the case of modifying the polyurethane composition in the prepolymer method, for example, in order to prevent the hardness of the polishing pad from decreasing due to frictional heat during polishing, the polyol component or isocyanate component of the urethane prepolymer, the diamines of the curing agent, Studies on materials to be blended such as diols are underway.

  In Patent Document 1, an amine curing agent is used in combination with an aromatic compound having one hydroxyl group and / or an aromatic compound having one amino group to disperse a relatively low molecular weight polymer in a polyurethane resin. Thus, it is disclosed that the “stickiness” of the polyurethane resin itself is reduced and the dressability is improved while maintaining the hardness of the polyurethane resin.

  Patent Document 2 discloses that by using a plurality of specific curing agents, a polishing pad having appropriate rigidity and toughness can be obtained without greatly reducing the hardness.

JP 2013-066977 A Japanese Patent No. 5725300

  The inventors of the present invention have considered that the conventional polishing pad has insufficient heat resistance and dressability, and therefore the hardness of the polishing pad is reduced by frictional heat during polishing, and the dressing time is increased. In order to solve this problem, in order to improve the heat resistance and dressing property of the polishing pad, intensive studies were conducted on a curing agent added to and mixed with the prepolymer.

That is, the present invention provides the following.
[1]
A polishing pad having a polishing layer made of polyurethane resin,
The polishing layer is formed by curing a polyurethane resin curable composition containing a polyisocyanate compound and a curing agent,
The curing agent includes an amine curing agent and a polyol curing agent having a bisphenol A structure represented by the following formula (I):
The molar ratio of the amine curing agent and the polyol curing agent having the bisphenol A structure is 90:10 to 70:30,
Ratio of the total number of moles of NH of the amine curing agent and the number of moles of OH of the polyol curing agent having the bisphenol A structure to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH + mol of OH) Number) / number of moles of NCO) of 0.7 to 1.1.

(In the formula, R is an alkylene group having 2 or 3 carbon atoms, and n and m are each independently an integer of 1 to 7)
[2]
The polishing pad according to [1], wherein the polyol curing agent having the bisphenol A structure has a number average molecular weight of 350 to 600.

[3]
The polishing pad according to [1] or [2], wherein the amine curing agent includes 3,3′-dichloro-4,4′-diaminodiphenylmethane.

[4]
Following formula (II)
{(D hardness of polishing pad saturated and swollen with 20 ° C. water) − (D hardness of polishing pad saturated and swollen with hot water at 50 ° C.)} / (D of polishing pad saturated and swollen with water at 20 ° C.) Hardness) (II)
The polishing pad according to any one of [1] to [3], in which the value of is less than or equal to 0.2.

[5]
The polishing pad according to any one of [1] to [4], wherein the polyurethane resin curable composition contains fine hollow spheres.

[6]
The polishing pad according to any one of [1] to [5], wherein the abrasion mass of the polishing layer by continuous 1000 times Taber abrasion test is 100 mg or more.

  According to the present invention, it is possible to obtain a polishing pad that has excellent heat resistance, suppresses a decrease in hardness due to frictional heat during polishing, and has excellent dressability.

(Function)
The curing agent is a compound that reacts with the isocyanate group in the prepolymer to complete the polyurethane resin. In the present invention, a polyol curing agent having a bisphenol A structure represented by the following formula is used in combination with an amine curing agent as a curing agent.

(In the formula, R is an alkylene group having 2 or 3 carbon atoms, and n and m are each independently an integer of 1 to 7)
Although not bound by theory, in the polishing pad of the present invention, the stacking (stacking) interaction between the aromatic rings of bisphenol A works between polyol curing agents having a plurality of bisphenol A structures. And it is presumed that the dressing is excellent.

  The alkylene group preferably has 2 or more carbon atoms for use as a spacer. However, if the alkylene group has too many carbon atoms, the heat resistance of the polishing layer using the polyol curing agent having the bisphenol A structure of formula (I) It becomes low. For this reason, it is important in the present invention that the carbon number of R is in the range of 2 or 3.

In order to use an alkylene group as a spacer, it is desirable that the value of n and / or m is a certain number or more, but if the value of n and / or m is too large, the bisphenol A structure of formula (I) Therefore, the heat resistance of the polishing layer using the polyol curing agent having a lower value is lowered. Moreover, when the value of n and / or m becomes too large, the molecular weight of the polyurethane obtained after curing becomes too large and the dressing property is lowered. For this reason, it is important in the present invention that n and m are each independently an integer of 1 to 7.
(Polyol curing agent having bisphenol A structure)
By using a polyol curing agent having a specific bisphenol A structure represented by the formula (I), the heat resistance and dressing property of a polishing pad obtained unexpectedly could be improved moderately. In the above formula (I), R is an alkylene group having 2 or 3 carbon atoms, specifically ethylene, n-propylene or isopropylene, preferably ethylene or n-propylene. n is an integer of 1 to 7, an integer of 2 to 6 is more preferable, and an integer of 3 to 5 is particularly preferable. m is an integer of 1 to 7, an integer of 2 to 6 is more preferable, and an integer of 3 to 5 is particularly preferable.

The number average molecular weight of the polyol curing agent having a specific bisphenol A structure represented by the formula (I) is preferably 350 to 600, more preferably 370 to 580, and particularly preferably 400 to 550. Since the number average molecular weight of the polyol curing agent having the specific bisphenol A structure represented by the formula (I) is smaller than the number average molecular weight of the polyol component in the polyisocyanate compound described later, phase separation is likely to occur, and elasticity An excellent polishing pad can be obtained.
(Amine-based curing agent)
In this invention, the amine hardening | curing agent demonstrated below can be illustrated, for example.

  Examples of the polyamine include diamines, which include alkylene diamines such as ethylene diamine, propylene diamine, and hexamethylene diamine; diamines having an aliphatic ring such as isophorone diamine and dicyclohexylmethane-4,4′-diamine; 3 Diamine having an aromatic ring such as 3,3′-dichloro-4,4′-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (hereinafter abbreviated as MOCA); 2-hydroxyethylethylenediamine, 2-hydroxy Diamines having hydroxyl groups such as ethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc. , Hydroxyalkyl alkylene diamine particular; and the like. Trifunctional triamine compounds and tetrafunctional or higher polyamine compounds can also be used.

  A particularly preferred curing agent is MOCA described above, and the chemical structure of MOCA is as follows.

(Amount of curing agent used)
The heat resistance of the polishing pad can be adjusted by the chemical structure of the polyol curing agent having a bisphenol A structure, but can also be adjusted by the blending ratio of the amine curing agent and the polyol curing agent having the bisphenol A structure. This mixing ratio is preferably 60:40 to 80:20, more preferably 65:35 to 75:25, by weight ratio of amine curing agent: polyol curing agent having a bisphenol A structure.

The molar ratio between the amine curing agent and the polyol curing agent having a bisphenol A structure is 90:10 to 70:30, more preferably 85:15 to 75:25.
Furthermore, the ratio of the total number of moles of NH of the amine curing agent and the number of moles of OH of the polyol curing agent having a bisphenol A structure to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH + number of moles of OH) ) / NCO mole number) is 0.7 to 1.1, preferably 0.8 to 1.0.

The total amount of the curing agent is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, with the amount of polyisocyanate compound (amount of prepolymer) being 100 parts by weight.
(Heat-resistant)
The polishing pad of the present invention has the following formula (II)
{(D hardness of polishing pad saturated and swollen with 20 ° C. water) − (D hardness of polishing pad saturated and swollen with hot water at 50 ° C.)} / (D of polishing pad saturated and swollen with water at 20 ° C.) Hardness) (II)
Is preferably 0.2 or less, and more preferably 0.18 or less. When the value of the formula (II) is larger than 0.2, the heat resistance of the polishing pad is insufficient, and the polishing pad cannot maintain sufficient hardness due to frictional heat during polishing, so that the polishing performance cannot be exhibited.
(Dressing)
The polishing layer in the polishing pad of the present invention preferably has a wear mass of 100 mg or more, more preferably 120 mg or more, as determined by 1000 continuous Taber abrasion tests. If the value of the wear mass by the continuous Taber abrasion test is less than 100 mg, the dressing property of the polishing pad is insufficient, the dressing time is increased, and the productivity of the polishing pad is lowered.
(Polishing pad)
The polishing pad of the present invention has a polishing layer made of a polyurethane foam resin. The polishing layer is disposed at a position in direct contact with the material to be polished, and the other part of the polishing pad may be made of a material for supporting the polishing pad, for example, an elastic material such as rubber. Depending on the rigidity of the polishing pad, the entire polishing pad can be a single polishing layer.

The polishing pad of the present invention is similar in shape to a general polishing pad except that it is difficult to cause defects such as scratches on the material to be polished when polishing scraps accumulate, and is used in the same manner as a general polishing pad. For example, the polishing layer can be pressed against the material to be polished while rotating the polishing pad, or can be polished against the polishing layer while rotating the material to be polished.
(Polishing pad manufacturing method)
The polishing pad of the present invention can be prepared by a generally known production method such as molding or slab molding. First, a polyurethane block is formed by these manufacturing methods, the block is formed into a sheet shape by slicing or the like, a polishing layer formed from a polyurethane resin is formed, and bonded to a support or the like. Alternatively, the polishing layer can be formed directly on the support.

  More specifically, the polishing layer has a double-sided tape attached to the surface opposite to the polishing surface of the polishing layer, cut into a predetermined shape, and becomes the polishing pad of the present invention. The double-sided tape is not particularly limited, and any double-sided tape known in the art can be selected and used. In addition, the polishing pad of the present invention may have a single layer structure consisting only of a polishing layer, and a multilayer in which another layer (lower layer, support layer) is bonded to the surface of the polishing layer opposite to the polishing surface. It may consist of

The polishing layer is formed by preparing a polyurethane resin curable composition containing a polyisocyanate compound and curing the polyurethane resin curable composition.
The polishing layer is composed of a foamed polyurethane resin. Foaming can be carried out by dispersing a foaming agent containing fine hollow spheres in the polyurethane resin. In this case, the polyurethane resin is foamed and cured containing a polyisocyanate compound and a foaming agent. It is shape | molded by preparing an adhesive composition and foam-curing a polyurethane resin foam-curable composition.

  The polyurethane resin curable composition may be a two-component composition prepared by mixing, for example, a liquid A containing a polyisocyanate compound and a liquid B containing other components. The B liquid containing the other components can be further divided into a plurality of liquids and mixed with three or more liquids to form a composition.

Here, the polyisocyanate compound refers to a prepolymer prepared by a reaction of the following polyisocyanate component and polyol component, which is often used in the art. As the prepolymer, those commonly used in the art containing unreacted isocyanate groups can be used in the present invention.
(Polyisocyanate component)
As a polyisocyanate component, for example,
m-phenylene diisocyanate,
p-phenylene diisocyanate,
2,6-tolylene diisocyanate (2,6-TDI),
2,4-tolylene diisocyanate (2,4-TDI),
Naphthalene-1,4-diisocyanate,
Diphenylmethane-4,4′-diisocyanate (MDI),
4,4′-methylene-bis (cyclohexyl isocyanate) (hydrogenated MDI),
3,3′-dimethoxy-4,4′-biphenyl diisocyanate,
3,3′-dimethyldiphenylmethane-4,4′-diisocyanate,
Xylylene-1,4-diisocyanate,
4,4′-diphenylpropane diisocyanate,
Trimethylene diisocyanate,
Hexamethylene diisocyanate,
Propylene-1,2-diisocyanate,
Butylene-1,2-diisocyanate,
Cyclohexylene-1,2-diisocyanate,
Cyclohexylene-1,4-diisocyanate,
p-phenylene diisothiocyanate,
Xylylene-1,4-diisothiocyanate,
Ethylidine diisothiocyanate etc. are mentioned.
(Polyol component)
As a polyol component, for example,
Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1, Diols such as 5-pentanediol and 1,6-hexanediol;
Polyether polyols such as polytetramethylene glycol (PTMG), polyethylene glycol, polypropylene glycol;
Polyester polyols such as a reaction product of ethylene glycol and adipic acid and a reaction product of butylene glycol and adipic acid;
Polycarbonate polyols;
Polycaprolactone polyol;
Etc.

The number average molecular weight of the polyol component is preferably 1500 to 5000. When the number average molecular weight of the polyol component is larger than the number average molecular weight of the polyol curing agent having a bisphenol A structure, phase separation is likely to occur and a polishing pad having excellent elasticity can be obtained.
(Curing agent)
As described above, the curing agent is used in combination with an amine curing agent and a polyol curing agent having a bisphenol A structure represented by the formula (I). When a combination of an amine curing agent and a polyol curing agent having a bisphenol A structure represented by formula (I) is used, it is formed by curing a polyurethane resin curable composition as compared to the case of using only an amine curing agent. It is possible to suppress heat generation that occurs during the process. By suppressing the heat generation, it is possible to suppress the micro hollow spheres contained in the polyurethane resin curable composition from excessively expanding, and it is possible to suppress variations in the foamed shape and the aperture diameter of the polishing layer.
(Foaming agent)
A foam can be formed by mixing micro hollow spheres with polyurethane resin. The micro hollow sphere is obtained by heating and expanding an unfoamed heat-expandable microsphere composed of an outer shell (polymer shell) made of a thermoplastic resin and a low-boiling hydrocarbon encapsulated in the outer shell. . As the polymer shell, for example, thermoplastic resins such as acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, vinyl chloride-ethylene copolymer can be used. Similarly, as the low boiling point hydrocarbon encapsulated in the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether and the like can be used.
(Other ingredients)
In addition, a catalyst generally used in the art may be added to the foam curable composition.

The invention is illustrated experimentally by the following examples, which are not intended to be construed as limiting the scope of the invention to the following examples.
(material)
The materials used in the following examples are listed.
・ Product name of urethane prepolymer:
Novaretan UP-161 manufactured by Mitsubishi Plastics
・ Product name of curing agent:
MOCA (amine curing agent)
Pandex E made by DIC
Polyol curing agent having bisphenol A structure New Pole BPE-40 manufactured by Sanyo Kasei Co., Ltd.
New pole BP-3P made by Sanyo Chemical
Ether type polyol curing agent PTMG1000 manufactured by Mitsubishi Chemical Corporation
・ Product name of micro hollow sphere:
EXPANCEL 551DE40d42 made by Nippon Philite
Example 1
100 g of NCO equivalent 460 urethane prepolymer (novaletane UP-161) with tolylene diisocyanate as the main component in component A, Pandex E (NH equivalent = 133.5) as a curing agent and Newpol BPE- in component B 30 g of 40 (number average molecular weight = 410, OH equivalent = 205) mixed at a weight ratio of 70:30, and 1 g of hollow microspheres (EXPANCEL 551DE40d42) were prepared for the C component. The B component curing agent has a molar ratio of 80:20 between the amine curing agent and the polyol curing agent having a bisphenol A structure. Also, the ratio of the total number of moles of NH of the amine-based curing agent of component B and the number of moles of OH of the polyol curing agent having a bisphenol A structure to the number of moles of NCO of the prepolymer of component A (number of moles of NH The number of moles of + OH) / number of moles of NCO) is 0.9.

The A component and the B component were degassed in advance in advance, and then the A component, the B component, and the C component were supplied to the mixer.
The obtained mixed liquid was poured into a mold (200 mm × 300 mm square) heated to 80 ° C., heated and cured for 1 hour, and then the formed resin foam was extracted from the mold, and then at 120 ° C. Cure for 5 hours. This foam was sliced to a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

(Example 2)
Instead of the curing agent used in the B component of Example 1, Pandex E (NH equivalent = 133.5) and Newpol BP-3P (number average molecular weight = 530, OH equivalent = 265) were used in a weight ratio of 70:30. 30 g of what was mixed in the above was prepared. In the B component curing agent, the molar ratio of the amine curing agent and the polyol curing agent having a bisphenol A structure is 80:20. Also, the ratio of the total number of moles of NH of the amine-based curing agent of component B and the number of moles of OH of the polyol curing agent having a bisphenol A structure to the number of moles of NCO of the prepolymer of component A (number of moles of NH The number of moles of + OH) / number of moles of NCO) is 0.9. The A component and the C component were the same as in Example 1.

Thereafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.
(Comparative Example 1)
Instead of the curing agent used in the B component of Example 1, 30 g of Pandex E (NH equivalent = 133.5) was prepared. In the B component curing agent, the molar ratio of the amine curing agent and the polyol curing agent having a bisphenol A structure is 100: 0. The ratio of the number of moles of NH in the amine-based curing agent of the component B to the number of moles of NCO in the prepolymer of the component A (number of moles of NH / number of moles of NCO) is 0.9. The A component and the C component were the same as in Example 1.

Thereafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.
(Comparative Example 2)
In place of the curing agent used in the B component of Example 1, Pandex E (NH equivalent = 133.5) and PTMG1000 (number average molecular weight = 1000, OH equivalent = 500) were mixed at a weight ratio of 50:50. 42g was prepared. The B component curing agent has a molar ratio of the amine curing agent to the ether polyol curing agent of 80:20, and NH of the B component amine curing agent with respect to the number of moles of NCO of the A component prepolymer. The total ratio of the number of moles to the number of moles of OH of the ether-based polyol curing agent ((number of moles of NH + number of moles of OH) / number of moles of NCO) is 0.9. The A component and the C component were the same as in Example 1.

Thereafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.
(Test method)
(D hardness)
The D hardness was measured according to JISK6253-1997 / ISO7619. The D hardness of the polishing pad saturated and swollen with 20 ° C. water and the polishing pad saturated and swollen with 50 ° C. warm water were measured.

(Taber wear)
It measured according to the method according to the Taber abrasion test of Japanese Industrial Standard (JIS K 6902).

(Dressing)
The polishing pad was dressed for 10 minutes, and the polished surface before and after the dressing was observed with a scanning electron microscope (JEOL Ltd., JMS-5500LV) at a magnification of 100 times. The obtained image was binarized by image processing software (Image Analyzer V20LAB Ver. 1.3, manufactured by Nikon Corporation). The evaluation criteria were ◯ when the polished surface was not closed, and x when the polished surface was closed.

(Opening hole diameter variation)
The cross section of the polishing pad was observed with a scanning electron microscope (JEOL Co., Ltd., JMS-5500LV) magnified 100 times. The obtained image was binarized by image processing software (Image Analyzer V20LAB Ver. 1.3, manufactured by Nikon Corporation). The case where the opening was uniform was marked with ◯, and the case where a deformed opening was seen was marked with x.

(Polishing rate)
The conditions of the polishing test are as follows.
・ Use polishing machine: F-REX300 manufactured by Ebara Corporation
Disk: 3MA188 (# 100)
・ Rotation speed: (Surface plate) 70 rpm, (Top ring) 71 rpm
Polishing pressure: 3.5 psi
・ Abrasive: manufactured by Cabot, product number: SS25 (SS25 undiluted solution: pure water = 1: 1 mixture)
・ Abrasive temperature: 20 ℃
・ Abrasive discharge rate: 200ml / min
Work to be used (object to be polished): Tetraethoxysilane (TEOS) is formed on a 12-inch silicon wafer by PE-CVD so that the insulating film has a thickness of 1 μm. The pad surface temperature rises to 40-50 ° C.
The polishing rate is a value measured when 25 wafers were subjected to dummy polishing after performing dressing for 10 minutes.

  The results are shown in Table 1.

  As shown in Table 1, in the case of Comparative Example 1 and Comparative Example 2, since the heat resistance was poor and the value obtained from Formula II exceeded 0.2, the polishing pad was softened, the dressability was reduced, and polishing was performed. The rate has dropped. Further, in Comparative Example 1, the variation in the aperture diameter was large. Furthermore, since the comparative example 2 had too much Taber abrasion amount, the grinding | polishing surface suitable for grinding | polishing could not be obtained, and the grinding | polishing rate was not stabilized.

  On the other hand, in the case of Examples 1 and 2 using a curing agent in which a polyol curing agent having a bisphenol A structure represented by formula (I) was mixed with an amine curing agent, the heat resistance was improved and obtained from Formula II The value could be suppressed to 0.2 or less, and the hardness of the polishing pad could be maintained. In addition, the amount of Taber wear was large, and a polished surface suitable for polishing could be obtained. Therefore, a high polishing rate could be obtained.

  Therefore, by using a curing agent obtained by mixing a polyol curing agent having a specific bisphenol A structure represented by formula (I) with an amine-based curing agent, the polishing pad of the present invention is generated during a polishing operation using a slurry. It has been found that extreme softening of the polishing pad due to frictional heat or the like is suppressed, and hardness suitable for polishing is maintained, and this hardness maintenance greatly contributes to stabilization of polishing performance. Further, it was found that the amount of wear on the Taber became an appropriate amount, and a polishing surface suitable for polishing could be easily obtained, which greatly contributed to the improvement of dress performance.

Claims (6)

A polishing pad having a polishing layer made of polyurethane resin,
The polishing layer is formed by curing a polyurethane resin curable composition containing a polyisocyanate compound and a curing agent,
The curing agent includes an amine curing agent and a polyol curing agent having a bisphenol A structure represented by the following formula (I):
The molar ratio of the amine curing agent and the polyol curing agent having the bisphenol A structure is 90:10 to 70:30,
Ratio of the total number of moles of NH of the amine curing agent and the number of moles of OH of the polyol curing agent having the bisphenol A structure to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH + mol of OH) Number) / number of moles of NCO) of 0.7 to 1.1.

(In the formula, R is an alkylene group having 2 or 3 carbon atoms, and n and m are each independently an integer of 1 to 7)   The polishing pad according to claim 1, wherein the polyol curing agent having the bisphenol A structure has a number average molecular weight of 350 to 600.   The polishing pad according to claim 1, wherein the amine-based curing agent includes 3,3′-dichloro-4,4′-diaminodiphenylmethane. Following formula (II)
{(D hardness of polishing pad saturated and swollen with 20 ° C. water) − (D hardness of polishing pad saturated and swollen with hot water at 50 ° C.)} / (D of polishing pad saturated and swollen with water at 20 ° C.) Hardness) (II)
The polishing pad in any one of Claims 1-3 whose value of is 0.2 or less.   The polishing pad in any one of Claims 1-4 in which the said polyurethane resin curable composition contains a micro hollow sphere.   The polishing pad according to any one of claims 1 to 5, wherein the abrasion mass of the polishing layer by continuous 1000 Taber abrasion test is 100 mg or more.