JP6855202B2 - Abrasive pad - Google Patents

Description

The present invention relates to a polishing sheet or polishing pad for polishing materials that require a high degree of surface flatness, such as optical materials, semiconductor substrates, semiconductor wafers, hard disk substrates, liquid crystal glass substrates, and semiconductor devices. INDUSTRIAL APPLICABILITY The present invention is particularly preferably used 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, glass substrates for liquid crystals, and semiconductor devices are required to have extremely precise flatness. Further, on the surface of the semiconductor material, various materials having different hardness such as metal, organic and inorganic insulating materials are exposed. In order to polish the surface of such a material flatly, it is necessary that the surface of the polishing pad also maintains uniform rigidity. The desired flatness cannot be achieved if the surface stiffness of the polishing pad changes during the polishing operation.

For example, a considerable amount of polishing debris is generated at the end of one polishing operation from the start of polishing to the replacement of the polishing pad and the abrasive liquid. Due to the accumulation of polishing debris, the openings are clogged, the retention of slurry deteriorates, and frictional heat is generated. Therefore, during one polishing operation, the temperature of the surface of the material to be polished is from the beginning to the end. It rises over a wide temperature range, including 20 ° C to 70 ° C. In addition, the polishing liquid used for chemical mechanical polishing has a stronger chemical action (corrosion on the surface of non-polished material) as the temperature rises. Therefore, due to the surface of the polishing pad whose rigidity is locally reduced due to the temperature change of the object to be polished or the polishing liquid, precise flatness cannot be achieved, and only the metal part is preferentially polished (dishes). Etc. tend to occur easily.

Further, the accumulation of polishing debris is usually eliminated by roughening (dressing) the surface of the polishing pad with a dresser. If it takes too much time for this dress, that is, if the dressing speed is low, the polishing efficiency will deteriorate.

Many hard polishing pads are obtained by using urethane prepolymer, which is a reaction product of a polyol component and an isocyanate component, and adding and mixing a curing agent (chain extender) such as diamines or diols, a foaming agent, a catalyst, and the like. It is produced by a prepolymer method for curing a polyurethane composition to be obtained. In the prepolymer method, when the polyurethane composition is modified, for example, in order to prevent a decrease in the hardness of the polishing pad due to frictional heat during polishing, a polyol component or an isocyanate component of the urethane prepolymer, a diamine as a curing agent, etc. Studies on materials to be blended, such as diols, are underway.

In Patent Document 1, a polymer having a relatively low molecular weight is dispersed in a polyurethane resin by using an amine-based curing agent in combination with an aromatic compound having one hydroxyl group and / or an aromatic compound having one amino group. Therefore, it is disclosed that the "stickiness" of the polyurethane resin itself is reduced while maintaining the hardness of the polyurethane resin, and the dressing property is improved.

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 significantly reducing the hardness.

Japanese Unexamined Patent Publication No. 2013-066977 Japanese Patent No. 5725300

The present inventors considered that the conventional polishing pad does not have sufficient heat resistance and dressing property, and therefore, the hardness of the polishing pad decreases due to the frictional heat during polishing, and the dressing time increases. In order to solve this problem, in order to improve the heat resistance and dressing property of the polishing pad, a hardener to be added and mixed with the prepolymer was intensively studied.

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 contains an amine-based curing agent and a polyol curing agent having a bisphenol A structure represented by the following formula (I).
The molar ratio of the amine-based curing agent to the polyol curing agent having a bisphenol A structure is 90:10 to 70:30.
The total ratio of the number of moles of NH of the amine-based curing agent to the number of moles of OH of the polyol curing agent having the bisphenol A structure with respect to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH + mole of OH). A polishing pad having a 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 independently integers of 1 to 7).
[2]
The polishing pad according to [1], wherein the number average molecular weight of the polyol curing agent having a bisphenol A structure is 350 to 600.

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

[4]
The following formula (II)
{(D hardness of polishing pad saturated and swollen with water at 20 ° C)-(D hardness of polishing pad saturated and swollen with warm water at 50 ° C)} / (D hardness of polishing pad saturated and swollen with water at 20 ° C) Hardness) (II)
The polishing pad according to any one of [1] to [3], wherein the value of is 0.2 or less.

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

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

According to the present invention, it is possible to obtain a polishing pad having excellent heat resistance, suppressing a decrease in hardness due to frictional heat during polishing, and having excellent dressing property.

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

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

The alkylene group preferably has 2 or more carbon atoms in order to be used as a spacer, but if the alkylene group has too large a carbon number, the heat resistance of the polishing layer using the polyol curing agent having the bisphenol A structure of the formula (I) The sex becomes low. Therefore, it is important in the present invention that the carbon number of R is in the range of 2 or 3.

Further, in order to utilize the 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 the formula (I) The heat resistance of the polishing layer using the polyol curing agent having the above is lowered. Further, if the values of n and / or m become too large, the molecular weight of the polyurethane obtained after curing becomes too large, and the dressing property deteriorates. Therefore, it is important in the present invention that n and m are independently integers of 1 to 7.
(Polycarbonate curing agent having a 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 the polishing pad obtained unexpectedly could be appropriately improved. In the above formula (I), R is an alkylene group having 2 or 3 carbon atoms, specifically ethylene, n-propylene and isopropylene, preferably ethylene and n-propylene. n is an integer of 1 to 7, with an integer of 2 to 6 being more preferred, and an integer of 3 to 5 being particularly preferred. m is an integer of 1 to 7, with an integer of 2 to 6 being more preferred, and an integer of 3 to 5 being particularly preferred.

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. When the number average molecular weight of the polyol curing agent having a 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 the present invention, for example, the amine-based curing agent described below can be exemplified.

Examples of polyamines include diamines, which include alkylenediamines such as ethylenediamine, propylenediamine and hexamethylenediamine; diamines having an aliphatic ring such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; 3 , 3'-Dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (hereinafter abbreviated as MOCA) and other diamines having an aromatic ring; 2-hydroxyethylethylenediamine, 2-hydroxy Diamines having hydroxyl groups such as ethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine; Be done. In addition, trifunctional triamine compounds and tetrafunctional or higher functional polyamine compounds can also be used.

A particularly preferable curing agent is the above-mentioned MOCA, and the chemical structure of this 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 compounding ratio of the amine-based curing agent and the polyol curing agent having a bisphenol A structure. This compounding ratio is preferably an amine-based curing agent: a polyol curing agent having a bisphenol A structure, which is 60:40 to 80:20, and more preferably 65:35 to 75:25.

The molar ratio of the amine-based curing agent to the polyol curing agent having a bisphenol A structure is 90: 10 to 70:30, more preferably 85: 15 to 75:25.
Further, the total ratio of the number of moles of NH of the amine-based 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). ) / Number of moles of NCO) 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 the 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 water at 20 ° C)-(D hardness of polishing pad saturated and swollen with warm water at 50 ° C)} / (D hardness of polishing pad saturated and swollen with water at 20 ° C) Hardness) (II)
The value of is preferably 0.2 or less, and more preferably 0.18 or less. If 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.
(Dress)
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 a result of a continuous Taber wear test 1000 times. If the value of the wear mass obtained by the continuous Taber wear 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 foamed polyurethane resin. The polishing layer is arranged at a position in direct contact with the material to be polished, and the other portion of the polishing pad may be composed of a material for supporting the polishing pad, for example, a highly elastic material such as rubber. Depending on the rigidity of the polishing pad, the entire polishing pad can be one polishing layer.

The polishing pad of the present invention has no significant difference in shape from a general polishing pad, except that the material to be polished is less likely to cause defects such as scratches when polishing debris accumulates, 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 for polishing, or the material to be polished can be pressed against the polishing layer while being rotated for polishing.
(Manufacturing method of polishing pad)
The polishing pad of the present invention can be produced by a generally known manufacturing method such as molding or slab molding. First, a polyurethane block is formed by these manufacturing methods, the block is made into a sheet by slicing or the like, a polishing layer formed of a polyurethane resin is formed, and the block is 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 side of the polishing layer opposite to the polishing surface, and is cut into a predetermined shape to obtain the polishing pad of the present invention. The double-sided tape is not particularly limited, and can be arbitrarily selected and used from the double-sided tapes known in the art. Further, the polishing pad of the present invention may have a single-layer structure consisting of only a polishing layer, and is a multi-layer in which another layer (lower layer, support layer) is bonded to the surface side 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, but foaming can be performed by dispersing a foaming agent containing microhollow spheres in the polyurethane resin, and in this case, foaming and curing the polyurethane resin containing the polyisocyanate compound and the foaming agent. It is formed by preparing a sex composition and foam-curing the polyurethane resin foam-curable composition.

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

Here, the polyisocyanate compound refers to a prepolymer prepared by the reaction of the following polyisocyanate component and a polyol component, which is often used in the art. As the prepolymer, those generally used in the art containing unreacted isocyanate groups can also be used in the present invention.
(Polyisocyanate component)
Examples of the polyisocyanate component include
m-phenylenedi isocyanate,
p-phenylenediocyanate,
2,6-Toluene diisocyanate (2,6-TDI),
2,4-Toluene 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'-biphenyldiisocyanate,
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-Phenylisothiocyanate,
Xylylene-1,4-diisothiocyanate,
Ethilidine diisothiocyanate and the like can be mentioned.
(Polycarbonate component)
As the polyol component, for example
Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentandiol, 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 polyol;
Polycaprolactone polyol;
And so on.

The number average molecular weight of the polyol component is preferably 1500-5000. 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.
(Hardener)
As the curing agent, as described above, an amine-based curing agent and a polyol curing agent having a bisphenol A structure represented by the formula (I) are used in combination. When an amine-based curing agent and a polyol curing agent having a bisphenol A structure represented by the formula (I) are used in combination, the polyurethane resin curable composition is cured and formed as compared with the case where only the amine-based curing agent is used. It is possible to suppress the heat generation generated during the operation. By suppressing heat generation, it is possible to suppress excessive expansion of the minute hollow spheres contained in the polyurethane resin curable composition, and it is possible to suppress variations in the foamed shape and opening diameter of the polishing layer.
(Foaming agent)
A foam can be formed by mixing the fine hollow spheres with the polyurethane resin. The microhollow sphere refers to an unexpanded heat-expandable microsphere composed of an outer shell (polymer shell) made of a thermoplastic resin and a low boiling point hydrocarbon contained in the outer shell, which is heated and expanded. .. As the polymer shell, for example, a thermoplastic resin such as an acrylonitrile-vinylidene chloride copolymer, an acrylonitrile-methylmethacrylate copolymer, or a vinyl chloride-ethylene copolymer can be used. Similarly, as the low boiling point hydrocarbon contained 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 present invention will be described experimentally with the following examples, but the following description is 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-based curing agent)
DIC Pandex E
A polyol curing agent with a bisphenol A structure Nieuport BPE-40 manufactured by Sanyo Chemical Industries, Ltd.
Sanyo Kasei New Pole BP-3P
Ether-based 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 urethane prepolymer (Novaletan UP-161) having an NCO equivalent of 460 containing tolylene diisocyanate as the main component in the A component, and Pandex E (NH equivalent = 133.5) and New Pole BPE-, which are curing agents, in the B component. 30 g of a mixture of 40 (number average molecular weight = 410, OH equivalent = 205) at a weight ratio of 70:30 was prepared, and 1 g of a micro hollow sphere (EXPANCEL 551DE40d42) was prepared as the C component. The curing agent for component B has a molar ratio of an amine-based curing agent and a polyol curing agent having a bisphenol A structure of 80:20. Further, 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) / the number of moles of NCO) is 0.9.

After defoaming the A component and the B component in advance under reduced pressure, the A component, the B component and the C component were supplied to the mixer.
The obtained mixed solution was cast into a mold (200 mm × 300 mm square) heated to 80 ° C., heated for 1 hour to cure, and then the formed resin foam was extracted from the mold and then at 120 ° C. Cured 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 Nieuport BP-3P (number average molecular weight = 530, OH equivalent = 265) were used in a weight ratio of 70:30. 30 g of the mixture was prepared. The curing agent for component B has a molar ratio of an amine-based curing agent and a polyol curing agent having a bisphenol A structure of 80:20. Further, 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) / the number of moles of NCO) is 0.9. The components A and C were the same as in Example 1.

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

After that, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.
(Comparative Example 2)
Instead 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. Was prepared in an amount of 42 g. The curing agent for component B has a molar ratio of the amine-based curing agent and the ether-based polyol curing agent of 80:20, and the NH of the amine-based curing agent for component B has a molar ratio of NCO to the prepolymer of component A. 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 components A and C were the same as in Example 1.

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

(Taber wear)
The measurement was performed according to the method according to the Taber wear test of Japanese Industrial Standards (JIS K 6902).

(Dress)
The polishing pad was dressed for 10 minutes, and the polished surface before and after the dressing was observed with a scanning electron microscope (JMS-5500LV, manufactured by JEOL Ltd.) 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 as follows: those in which the openings on the polished surface were not closed were marked with ◯, and those in which the openings on the polished surface were blocked were marked with x.

(Variation of opening diameter)
The cross section of the polishing pad was observed with a scanning electron microscope (manufactured by 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). Those with uniform openings were marked with ◯, and those with deformed holes were marked with x.

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

The above results are shown in Table 1.

As shown in Table 1, in the cases of Comparative Example 1 and Comparative Example 2, the heat resistance was poor and the value obtained from Equation II exceeded 0.2, so that the polishing pad was softened, the dressability was lowered, and polishing was performed. The rate has dropped. Further, in Comparative Example 1, there was a large variation in the opening diameter. Further, in Comparative Example 2, the amount of taber wear was too large, so that a polished surface suitable for polishing could not be obtained, and the polishing rate was not stable.

On the other hand, in the cases of Examples 1 and 2 using a curing agent in which a polyol curing agent having a bisphenol A structure represented by the formula (I) was mixed with an amine-based curing agent, the heat resistance was improved and the heat resistance was obtained from the 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 in which a polyol curing agent having a specific bisphenol A structure represented by the formula (I) is mixed with an amine-based curing agent, the polishing pad of the present invention is generated during a polishing operation using a slurry. It was found that the extreme softening of the polishing pad due to frictional heat and the like was suppressed, and the hardness suitable for the polishing process was maintained, and this hardness maintenance greatly contributed to the stabilization of the polishing performance. Further, it was found that the amount of taber wear became an appropriate amount, and a polished surface suitable for polishing could be easily obtained, which greatly contributed to the improvement of dress performance.

Claims (7)

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 contains an amine-based curing agent and a polyol curing agent having a bisphenol A structure represented by the following formula (I).
The molar ratio of the amine-based curing agent to the polyol curing agent having a bisphenol A structure is 90:10 to 70:30.
The total ratio of the number of moles of NH of the amine-based curing agent to the number of moles of OH of the polyol curing agent having the bisphenol A structure with respect to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH + mole of OH). A polishing pad having a 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 independently integers of 1 to 7). The polishing pad according to claim 1, wherein the polyol curing agent having a bisphenol A structure has a number average molecular weight of 350 to 600. The polishing pad according to claim 1 or 2, wherein the amine-based curing agent contains 3,3'-dichloro-4,4'-diaminodiphenylmethane. The following formula (II)
{(D hardness of polishing pad saturated and swollen with water at 20 ° C)-(D hardness of polishing pad saturated and swollen with warm water at 50 ° C)} / (D hardness of polishing pad saturated and swollen with water at 20 ° C) Hardness) (II)
The polishing pad according to any one of claims 1 to 3, wherein the value of is 0.2 or less. The polishing pad according to any one of claims 1 to 4, wherein the polyurethane resin curable composition contains microhollow spheres. The polishing pad according to any one of claims 1 to 5, wherein the polishing layer has a wear mass of 100 mg or more in a continuous Taber wear test 1000 times. The polishing pad according to any one of claims 1 to 6, wherein the curing agent comprises the amine-based curing agent and the polyol curing agent having a bisphenol A structure .