JP2019063903A - Polishing pad - Google Patents

Abstract

To provide a polishing pad which is excellent in wet heat resistance and can suppress occurrence of defects in a polished object.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 curing agent and a polyol curing agent, and an amount of the polyol curing agent detected by an elute test is performed on the polishing layer is 0.10% or less with respect to the weight of the polishing layer.SELECTED DRAWING: None

Description

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

  Optical materials, semiconductor wafers, hard disk substrates, glass substrates for liquid crystals, semiconductor devices, etc. are required to have extremely precise flatness. In particular, on the surface of the material in the semiconductor device manufacturing process, various materials with different hardness such as metal, organic and inorganic insulating materials are exposed. In order to flatten the surface of such a material, 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 can not be achieved.

  For example, considerable polishing debris is generated from the start of polishing to the end of one polishing operation of the polishing pad. The surface temperature of the material to be polished during one polishing operation is from the beginning to the end of the polishing operation, since the accumulation of polishing debris causes the opening to be clogged, resulting in deterioration of the retention of the slurry and generation of frictional heat. It rises and changes in a wide temperature range including 20 ° C-70 ° C. In addition, the polishing solution used for chemical mechanical polishing becomes stronger in chemical action (corrosion of the surface of the object to be polished) as the temperature rises. Therefore, precise flatness can not be achieved due to the surface of the polishing pad whose rigidity is locally reduced due to the temperature change of the object to be polished and the polishing solution, and defects are likely to increase due to deformation or clogging of the pad. It becomes a tendency.

  Many hard polishing pads use urethane prepolymers, which are reaction intermediates between polyol components and isocyanate components, and add and mix curing agents (chain extenders) such as diamines and / or diols, blowing agents, catalysts, etc. Manufactured by a prepolymer method which cures the resulting polyurethane composition. When modifying the polyurethane composition in the prepolymer method, for example, in order to suppress the decrease in hardness of the polishing pad due to frictional heat at the time of polishing, the polyol component of the urethane prepolymer, the diamine component of the isocyanate component and the curing agent Investigation of materials to be blended such as diols is in progress.

  Patent Document 1 discloses that relatively low molecular weight polymers are dispersed in a polyurethane resin by using an amine curing agent in combination with an aromatic compound having one hydroxyl group and / or an aromatic compound having one amino group. It is disclosed that the "toughness" of the polyurethane resin itself is reduced while the hardness of the polyurethane resin is maintained, and the dressing property is improved.

JP, 2013-066977, A

  However, when examined by the present inventors, when a diamine and a diol are used in combination as a curing agent, the reaction rate of the diol is lower than that of the diamine, so the diol does not react and is cured as an unreacted residue. It was found to be contained in the polyurethane resin composition of And it turned out that this unreacted residue adheres to a thing to be ground as an organic residue at the time of grinding, and generates a defect. Therefore, as a result of intensive studies by the present inventors, it was found that the result obtained by measuring the abrasive layer by the elution test was related to the amount of unreacted curing agent, and the amount of unreacted curing agent was small. By using the polishing layer, the present invention can be completed, which can suppress the generation of organic residues during polishing and can suppress the generation of defects in an object to be polished.

That is, the present invention provides the following.
[1]
A polishing pad having a polishing layer made of polyurethane resin, comprising:
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,
The polishing pad, wherein the amount of the polyol curing agent detected when an elution test is performed on the polishing layer is 0.10% or less of the weight of the polishing layer.

[2]
The polishing pad as described in [1] which contains the polyol whose primary hydroxylation ratio of the said polyol hardening | curing agent is 60% or more.

[3]
The polishing pad according to [1] or [2], wherein the number average molecular weight of the polyol contained in the polyol curing agent is 500 to 6000.

[4]
The polishing pad according to any one of [1] to [3], wherein the amine curing agent contains 3,3′-dichloro-4,4′-diaminodiphenylmethane.

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

[6]
It is a manufacturing method of the polishing pad in any one of [1]-[5],
Forming the polishing layer.

[7]
A method of polishing a surface of an optical material or a semiconductor material, characterized in that the polishing pad according to any one of [1] to [5] is used.

[8]
The method to reduce the defect at the time of grinding | polishing the surface of an optical material or a semiconductor material using the polishing pad in any one of [1]-[5].

  In the polishing pad of the present invention, the wet heat resistance can be improved by including a specific polyol curing agent as a curing agent, and further, the amount of unreacted polyol curing agent contained as a residue in the polishing layer By reducing the amount of organic residues attached to the object to be polished during polishing. As a result, according to the present invention, it is possible to provide a polishing pad which is excellent in wet heat resistance and can suppress the occurrence of defects in an object to be polished.

(Action)
In the polishing pad of the present invention, the amount of the polyol curing agent detected when the elution test is performed on the polishing layer is 0.10% or less with respect to the weight of the polishing layer.

  In the present invention, a polyol curing agent is reacted with a polyisocyanate compound so that more polyol curing agent is incorporated into the molecule of the polyurethane resin having a large molecular weight, and this is detected when an elution test is conducted. It is possible to obtain a polishing pad having a polishing layer whose amount of polyol curing agent is 0.10% or less with respect to the weight of the polishing layer. Polyol curing agent contained in the polyol curing agent necessary to obtain a polishing pad having an abrasive layer having an amount of a polyol curing agent of 0.10% or less based on the weight of the polishing layer detected in the elution test The characteristics are not particularly limited, but the primary hydroxylation ratio of the polyol (the ratio of the number of primary hydroxyl groups to the total number of hydroxyl groups), the number average molecular weight, the number of functional groups of hydroxyl groups, etc. Can.

(Dissolution test)
In the present invention, the amount of the polyol curing agent detected when the elution test is performed on the polishing layer means one measured according to the following measurement method and measurement conditions. The amount of the polyol curing agent detected in the elution test is 0.10% or less, more preferably 0.09% or less, based on the weight of the polishing layer.
(Measuring method)
In a polishing pad having a polishing layer, 0.5 g of a part of the polishing layer was collected, 10 g of DMF (N, N-dimethylformamide) was added to it, and shaken at 50 ° C. for 5 days. Thereafter, the solution was left to stand for 5 days at room temperature, 0.5 μl of the solution supernatant was measured, and the solvent was volatilized with a dryer at 80 ° C. to prepare a measurement sample. Then, the measurement sample is measured by a gas chromatograph mass spectrometer under the following measurement conditions. The polyol curing agent is identified from the analysis result of the gas chromatograph mass spectrometer. When polypropylene glycol or polyoxypropylene triol is used as a curing agent, gas chromatography mass spectrometry detects polypropylene glycol or polyoxypropylene triol derived from, for example, 1- (1-methylethoxy) -2-propanone etc. .
(Measurement conditions of gas chromatograph)
<Thermal decomposition conditions>
Thermal decomposition system: PY2020iD (manufactured by Frontier Lab Co., Ltd.)
Thermal decomposition temperature: 30 minutes at 550 ° C
<GC conditions>
Gas chromatograph: Agilent 6890N (manufactured by Agilent Technologies, Inc.)
Column: UltraALLOY-5 (MT / HT) -30M-0.25F (manufactured by Frontier Lab Co., Ltd.)
Inlet temperature: 360 ° C
Carrier gas: helium carrier gas flow rate: 1 ml / min split ratio: 1: 100
Temperature rising conditions: After holding for 5 minutes at 50 ° C., the temperature is raised to 320 ° C. at 30 ° C./min and held for 5 minutes at 320 ° C. Sample amount: 10 μl
<MS condition>
Mass spectrometer: JMS-Q100OGCK9 manufactured by JEOL Ltd.
Mass spectrometer temperature: interface 320 ° C, ion source 250 ° C
Detector voltage: -800V

  Next, a calibration curve is created using the identified polyol curing agent. 5 mg, 10 mg, and 50 mg of the polyol curing agent were collected, and 10 g of DMF (N, N-dimethylformamide) was added to each to dissolve it for use as a sample for calibration curve. Gel permeation chromatography (GPC) measurement was performed on the sample for calibration curve under the following measurement conditions, and a calibration curve was created based on the concentration and each peak area from the chart obtained.

  Then, on a polishing pad having a polishing layer, 0.5 g of a part of the polishing layer was collected, 10 g of DMF was added thereto, and shaken at 50 ° C. overnight. Then, it was left at normal temperature for 5 days, 1.5 ml of the supernatant of the solution was measured, centrifuged at 30,000 G for 60 minutes, and 0.5 ml of the supernatant was used as a measurement sample. And about a measurement sample, GPC measurement is performed on the following measurement conditions. The peak area of the unreacted polyol curing agent contained in the polishing layer was calculated by subjecting the obtained chart to data processing. The weight of the unreacted polyol curing agent contained in the polishing layer was calculated from the peak area of the obtained unreacted polyol curing agent and the calibration curve prepared as described above. Then, based on the weight of the polishing layer (0.5 g) and the weight of the obtained unreacted polyol curing agent, the weight% of the unreacted polyol curing agent to the polishing layer was calculated.

(Measurement conditions of GPC measurement)
Analyzer: Gel Permeation Chromatography L-7200 (Hitachi)
Column: Ohpak SB-803 HQ (exclusion limit 100000)
Mobile phase: 5 mM LiBr / DMF
Flow rate: 0.3 ml / min
Oven: 60 ° C
Detector: RI 40 ° C
Sample volume: 20 μL

(Polyol curing agent)
In the present invention, the wet heat resistance of the polishing pad can be improved by partially using a polyol curing agent as a curing agent.

  60% or more is preferable, 65% or more of the primary hydroxylation ratio (ratio of the number of primary hydroxyl groups to the number of all hydroxyl groups) of the polyol contained in a polyol curing agent is more preferable, and 70% or more is especially preferable. By using a polyol curing agent having a primary hydroxylation ratio within the above numerical range, the amount of the polyol curing agent detected in the elution test is 0.10% or less based on the weight of the polishing layer A polishing pad having a polishing layer can be obtained. The primary hydroxylation ratio of the polyol contained in the polyol curing agent can be measured, for example, according to the method described in JP-A-2000-344881.

  The number average molecular weight of the polyol contained in the polyol curing agent is preferably 500 to 6000, more preferably 800 to 5000, and particularly preferably 1000 to 4000.

The functional group number of the hydroxyl group of the polyol contained in the polyol curing agent is preferably 2 or more, more preferably 3 or more, and particularly preferably 4 or more.
As a polyol curing agent, 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, 1,6-hexanediol;
Trifunctional or higher functional polyols such as glycerin, trimethylolpropane and pentaerythritol;
Polyether polyols such as polytetramethylene glycol (PTMG), polyethylene glycol, polypropylene glycol, polyoxypropylene triol;
Polyester polyols such as a reaction product of ethylene glycol and adipic acid or a reaction product of butylene glycol and adipic acid;
Polycarbonate polyol;
Polycaprolactone polyol;
A polyol having a bisphenol A structure;
Etc.

(Polishing pad)
The polishing pad of the present invention has a polishing layer made of a foamed polyurethane resin. The polishing layer is disposed 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 one polishing layer.

  The polishing pad according to the present invention has the same shape as that of a general polishing pad except that it is difficult to cause defects due to the organic residue adhering to the material to be polished, and is used similarly to a general polishing pad. For example, the polishing layer can be pressed against the material to be polished for polishing while rotating the polishing pad, or the material to be polished can be pressed against the polishing layer for polishing.

(Method of manufacturing polishing pad)
The polishing pad of the present invention can be produced by generally known production methods such as molding and slab molding. First, a block of polyurethane is formed by these manufacturing methods, the block is formed into a sheet by slicing or the like, an abrasive layer formed of a polyurethane resin is formed, and the block is laminated 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 side opposite to the polishing surface of the polishing layer, and is cut into a predetermined shape to become the polishing pad of the present invention. There is no particular limitation on the double-sided tape, and any double-sided tape known in the art can be selected and used. The polishing pad of the present invention may have a single layer structure consisting only of the polishing layer, and a multilayer in which another layer (lower layer, support layer) is bonded to the surface opposite to the polishing surface of the polishing layer. Or it may consist of a multilayer.

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 carried out by dispersing a foaming agent containing micro hollow spheres in the polyurethane resin, and in this case, a polyurethane resin comprising a polyisocyanate compound, a curing agent and a foaming agent It is molded by preparing a foam curable composition and curing the polyurethane resin foam curable composition.

  The polyurethane resin curable composition can also be prepared as a two-component composition prepared by mixing, for example, solution A containing a polyisocyanate compound and solution B containing other curing agent components. The liquid B containing other components can be further divided into a plurality of liquids to form a composition constituted by mixing three or more liquids.

  Here, the polyisocyanate compound refers to a prepolymer prepared by the reaction of the following polyisocyanate component and a polyol component as often used in the art. As prepolymers, those generally used in the art containing unreacted isocyanate groups can also 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 and the like can be 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, 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 or a reaction product of butylene glycol and adipic acid;
Polycarbonate polyol;
Polycaprolactone polyol;
Etc.

(Amine curing agent)
In the present invention, for example, amine curing agents described below can be exemplified.
Examples of the amine-based curing agent include polyamines such as diamines, and examples thereof include alkylene diamines such as ethylene diamine, propylene diamine and hexamethylene diamine; and aliphatics such as isophorone diamine and dicyclohexylmethane-4,4'-diamine. A diamine having a ring; a diamine having an aromatic ring such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (alias: methylene bis-o-chloroaniline) (hereinafter abbreviated as MOCA); 2-hydroxy Hydroxic acid such as ethyl ethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine Diamines having, hydroxyalkyl alkylene diamine particular; and the like. Further, trifunctional triamine compounds and tetrafunctional or higher functional polyamine compounds can also be used.

  A particularly preferred curing agent is the aforementioned MOCA, the chemical structure of which is:

(The amount of curing agent used)
The wet heat resistance of the polishing pad can be adjusted by the compounding ratio of the amine curing agent and the polyol curing agent. This compounding ratio is preferably 75:25 to 45:55, more preferably 70:30 to 50:50, in weight ratio of amine curing agent: polyol curing agent.

The molar ratio of the amine curing agent to the polyol curing agent is 90:10 to 70:30, and more preferably 85:15 to 75:25.
Furthermore, the ratio of the sum of the number of moles of NH ₂ of the amine curing agent and the number of OH of the polyol curing agent to the number of moles of NCO of the polyisocyanate compound ((number of moles of NH ₂ + number of moles of OH) / NCO The number of moles of is 0.6 to 1.0, preferably 0.7 to 0.95.

  The amount of the entire curing agent is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight based on 100 parts by weight of the amount of the polyisocyanate compound (the amount of prepolymer).

(Micro hollow spheres)
Foams can be formed by mixing micro hollow spheres with a polyurethane resin. Micro hollow spheres refer to those obtained by heating and expanding unexpanded heat expandable microspheres comprising an outer shell (polymer shell) made of a thermoplastic resin and a low boiling point hydrocarbon contained in the outer shell. . As said polymer shell, thermoplastic resins, such as an acrylonitrile vinylidene chloride copolymer, an acrylonitrile methyl methacrylate copolymer, a vinyl chloride ethylene copolymer, etc. can be used, for example. Similarly, as low boiling point hydrocarbons contained in the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether and the like can be used.

(Other ingredients)
In addition, catalysts commonly used in the art may be added to the polyurethane resin curable composition.

(Wet heat resistance)
The wet heat resistance of the polishing pad can be evaluated by the following formula (I).
{(D hardness of polishing layer wet with water at 20 ° C.)-(D hardness of polishing layer wet with water at 50 ° C.)} / (D hardness of polishing layer wet with water at 20 ° C.)
(I)
In formula (I), from the D hardness of the polishing layer wetted with water at 20 ° C. and 50 ° C., the ratio of the D hardness of the polishing layer is calculated by decreasing the temperature of the polishing pad from 20 ° C. to 50 ° C. Do. Since the D hardness is measured using an indenter with a small tip, it is easy to detect changes in the surface (polished surface) of the polishing layer. Moreover, the temperature conditions (20 ° C., 50 ° C.) of the formula (I) mean the evaluation at the temperature at the initial stage of polishing and during the polishing within the temperature range (20 ° C. to 70 ° C.) changing during the polishing operation. Since the polishing pad in the polishing operation is always exposed to the slurry and becomes wet, the wetted polishing layer is used for evaluation.

  The value of Formula (I) of the polishing pad of the present invention is preferably 0.20 or less, and more preferably 0.18 or less. When the value of the formula (I) is 0.20 or less, the wet heat resistance of the polishing pad is sufficient, and the frictional heat at the time of polishing can maintain sufficient hardness of the polishing pad, thereby exhibiting polishing performance.

  The invention will be described experimentally by means of 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.
Urethane prepolymer:
Urethane prepolymer with NCO equivalent weight 460 based on 2,4-tolylene diisocyanate: Curing agent:
Amine curing agent MOCA ... 3,3'-dichloro-4,4'-diaminodiphenylmethane (alias: methylene bis-o-chloroaniline)
Polyol curing agent polyoxypropylene triol (65% primary hydroxylation, number average molecular weight 3000, OH equivalent = 1000)
Polypropylene glycol (primary hydroxylation ratio 2%, number average molecular weight 2000, OH equivalent = 1000)
・ Micro hollow spheres:
Nippon Fillite Ltd. EXPANCEL 551DE40d42

Example 1
100 g (parts) of a urethane prepolymer of NCO equivalent 460 having 2,4-tolylene diisocyanate as a main component to A component, and MOCA (NH ₂ equivalent = 133.5) and polyoxypropylene triol as a curing agent to B component 34 g (parts) of a mixture of (number average molecular weight = 3000, OH equivalent = 1000, primary hydroxylation ratio = 65%) at a weight ratio of 50: 50, C component to micro hollow spheres (EXPANCEL 551 DE 40 d 42) 1 g (parts I prepared each). The curing agent for the component B has a molar ratio of the amine curing agent to the polyol curing agent of 80:20. In addition, the ratio of the sum of the number of moles of NH ₂ of the amine curing agent of component B to the number of moles of OH of the polyol curing agent to the number of moles of NCO of the prepolymer of component A ((number of moles of NH ₂ + mole of OH Number) / number of NCO moles) is 0.9. In addition, in order to show a ratio, it describes as g indication, and prepares a required weight (part) according to the size of a block. The same applies to g (parts) notation.

After mixing the A component and the C component and degassing the mixture of the A component and the C component and the B component under reduced pressure respectively, the mixture of the A component and the C component and the B component were supplied to the mixer.
The resulting mixed solution is poured into a mold (890 mm × 890 mm square) heated to 80 ° C. and cured by heating for 1 hour, and then the formed resin foam is removed 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 having this as a polishing layer was obtained.

(Comparative example 1)
Instead of curing agent used in the B component of Example 1, MOCA and (NH ₂ equivalent = 133.5) and polypropylene glycol (number average molecular weight = 2000, OH equivalent weight = 1000, hydroxyl group ratio = 2%) 34g (parts) of what was mixed by the weight ratio 50:50 was prepared. The curing agent for the component B has a molar ratio of the amine curing agent to the polyol curing agent of 80:20. In addition, the ratio of the sum of the number of moles of NH ₂ of the amine curing agent of component B to the number of moles of OH of the polyol curing agent to the number of moles of NCO of the prepolymer of component A ((number of moles of NH ₂ + mole of OH Number) / number of NCO moles) is 0.9. The A component and the C component were the same as in Example 1.

Thereafter, in the same manner as in Example 1, a urethane sheet was prepared, and a polishing pad having this as a polishing layer was obtained.
The polishing pads obtained in Example 1 and Comparative Example 1 were subjected to gas chromatography mass spectrometry and GPC measurement according to the above measurement method and measurement conditions to calculate the amount of unreacted polyol curing agent with respect to the weight of the polishing layer. For each of the polishing pads of Example 1 and Comparative Example 1, the amount of unreacted polyol curing agent with respect to the weight of the polishing layer was 0.09% in Example 1: 0.12% in Comparative Example 1.

  The following evaluations of wet heat resistance (D hardness) and defects were performed on the polishing pads obtained in Example 1 and Comparative Example 1.

(D hardness)
The D hardness was measured according to JIS K6253-1997 / ISO 7619. The D hardness of the polishing layer wetted with water at 20 ° C. and the polishing layer wetted with water at 50 ° C. was measured using a Tekrok D-type hardness tester (GS 702). The wetted polishing layer refers to a layer that has been wetted by being immersed in deionized water at a predetermined temperature for 30 minutes. The wet urethane sheet was taken out of the deionized water and lightly wiped with filter paper to start measurement immediately. The sample was set to have a total thickness of at least 4.5 mm. Moreover, after making a pressure board contact a sample, D hardness read the numerical value 2 second after. The urethane sheets (about 1.3 mm in thickness) according to the examples and the comparative examples were measured in four sheets.

(Defect)
The defect is evaluated by polishing 25 substrates and measuring 5 substrates 21-25 after polishing in the high sensitivity measurement mode of a wafer surface inspection apparatus (Surfscan SP1DLS manufactured by KLA Tencor Corporation). The number of defects caused by the organic residue attached to the substrate surface was evaluated. In the evaluation of defects, less than 200 defects each having a diameter of 0.16 μm or more were evaluated as 、 and 200 or more as x on a 12-inch (300 mmφ) wafer.

(Polishing conditions)
The conditions of the polishing test are as follows.
・ Used polisher: F-REX 300 manufactured by Ebara Corporation
Disk: 3M A188 (# 60)
・ Number of rotations: (plate) 70 rpm, (top ring) 71 rpm
Polishing pressure: 3.5 psi
Abrasive: Cabot, product number: SS25 (SS25 stock solution: pure water = a mixture of 1: 1 weight ratio)
・ Abrasive temperature: 20 ° C
・ Abrasive discharge amount: 200 ml / min
Workpiece (object to be polished): Substrate formed by PE-CVD to have a thickness of 1 μm of insulating film of tetraethoxysilane on a 12 inch φ silicon wafer Initial temperature of polishing is from 20 ° C. Pad surface during polishing The temperature rises to 40-50 ° C.

  The above results are shown in Table 1.

  As shown in Table 1, in the case of Comparative Example 1, the value obtained from Formula I exceeded 0.2, and the wet heat resistance was poor. Moreover, the polishing pad obtained in Comparative Example 1 had a large number of defects caused by the organic residue attached to the substrate surface, and the evaluation was x.

  On the other hand, in the case of Example 1, the wet heat resistance was improved, the value obtained from the formula I could be suppressed to 0.2 or less, and the hardness of the polishing pad could be maintained. Moreover, the polishing pad obtained in Example 1 had a small number of defects due to the organic residue attached to the substrate surface, and the evaluation was ○.

  Therefore, the polishing pad of the present invention has high wet heat resistance, can suppress extreme softening of the polishing pad due to frictional heat generated during polishing using a slurry, and can maintain a hardness suitable for polishing. all right. Moreover, it was found that the polishing pad of the present invention can suppress the occurrence of defects in the object to be polished.

Claims (8)

A polishing pad having a polishing layer made of polyurethane resin, comprising:
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,
The polishing pad, wherein the amount of the polyol curing agent detected when an elution test is performed on the polishing layer is 0.10% or less of the weight of the polishing layer.   The polishing pad according to claim 1, comprising a polyol having a primary hydroxylation ratio of 60% or more of the polyol curing agent.   The polishing pad according to claim 1 or 2, wherein the number average molecular weight of the polyol contained in the polyol curing agent is 500 to 6000.   The polishing pad according to any one of claims 1 to 3, wherein the amine curing agent comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.   The polishing pad according to any one of claims 1 to 4, wherein the polyurethane resin curable composition further comprises micro hollow spheres. A method of manufacturing a polishing pad according to any one of claims 1 to 5, wherein
Forming the polishing layer.   A method of polishing a surface of an optical material or a semiconductor material, characterized by using the polishing pad according to any one of claims 1 to 5.   A method for reducing defects in polishing a surface of an optical material or a semiconductor material using the polishing pad according to any one of claims 1 to 5.