TWI621506B - Polishing pad and its manufacturing method - Google Patents

Abstract

The present invention provides a polishing pad which is excellent in polishing rate and flatness, and a method for producing the same, which is capable of reducing polishing damage caused by foreign matter during polishing processing. The polishing pad of the present invention comprises an abrasive layer having a polyurethane resin sheet, the polyurethane resin sheet comprising substantially spherical bubbles, and the polyurethane resin sheet having 0.10 W. / (m.k) or less, the polyurethane resin sheet at 45 ° C, initial load of 200 g, strain range of 0.1% to 0.5%, measurement frequency of 1.6 Hz, tensile mode The ratio of the loss elastic modulus to the storage elastic modulus is in the range of 0.130 to 0.270, and the compression modulus of the polyurethane resin sheet is 60% to 100%.

Description

Polishing pad and method of manufacturing same

The present invention relates to a polishing pad and a method of manufacturing the same. In particular, there is a polishing pad for chemical mechanical polishing (CMP) processing of a semiconductor device and a method for producing the same.

The surface of the material such as the glass substrate for a crucible, a hard disk, a mother glass for a thin liquid crystal display, a semiconductor wafer, or a semiconductor device is required to be flat. Therefore, the polishing is performed by a free abrasive grain using a polishing pad. The free abrasive grain method is a method of polishing a processed surface of a workpiece while supplying a slurry (polishing liquid) containing abrasive grains between the polishing pad and the workpiece.

In the polishing pad for a semiconductor device, the surface of the polishing pad is required to maintain the opening of the abrasive grains, to maintain the flatness of the surface of the semiconductor device, and to prevent the scratch of the surface of the semiconductor device. As a polishing pad which satisfies the above requirements, a polishing pad having a polishing layer made of a urethane resin foam is used.

The urethane resin foam is usually formed by curing by a reaction of a prepolymer containing an isocyanate compound containing a polyurethane bond with a curing agent (dry method). Further, a polishing pad is formed by cutting the foam into a sheet shape. Such a polishing pad having a hard abrasive layer formed by a dry method (hereinafter sometimes referred to simply as A hard (dry) polishing pad) forms a relatively small substantially spherical bubble inside the foam when the urethane resin is hardened, so that an opening is formed in the polished surface of the polishing pad formed by slicing (Opening), the opening (opening) can maintain the slurry during the grinding process.

As a polishing pad containing a urethane resin foam, for example, a polishing pad such as IC1000 (registered trademark, manufactured by Nitta Haas Co., Ltd.) is known. In addition, a polishing pad using a resin having little change in physical properties due to temperature rise due to polishing heat is known (Patent Document 1). Further, a polishing pad which dissipates heat on the flat plate side by a resin matrix having a high thermal conductivity is also known (Patent Document 2).

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent No. 4615813

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-297784

However, the conventional polishing pad containing a urethane resin foam generally has a large hardness, and it is difficult to prevent foreign matter (grinding debris, aggregates of abrasive grains, etc.) which are locally generated when the workpiece is polished. Grinding damage. On the other hand, if the hardness is reduced in order to reduce the problem of polishing damage, there is a problem that the entire polishing pad is softened, the polishing rate is small, and the flatness of the object to be polished is poor (the result is a film of a metal such as copper plating). A large depression occurs when the CMP process is performed).

The present invention has been made in view of the above problems, and aims to provide an improvement in research A polishing pad having a problem of polishing damage caused by local foreign matter during grinding, and having a high polishing rate and excellent flatness (especially, a recess can be reduced) and a method for producing the same.

In order to solve the above problems, the present invention adopts the following configuration.

<1> A polishing pad comprising an abrasive layer having a polyurethane resin sheet, the polyurethane resin sheet comprising substantially spherical bubbles, and the polyurethane resin sheet It has a thermal conductivity of 0.10 W/(m.k) or less, and the polyurethane resin sheet has an initial load of 200 g at 45 ° C, a strain range of 0.1% to 0.5%, a measurement frequency of 1.6 Hz, and a pull. The ratio of the loss elastic modulus to the storage elastic modulus in the stretch mode is in the range of 0.130 to 0.270, and the compression modulus of the polyurethane resin sheet is 60% to 100%.

The polishing pad according to the above aspect, wherein the polyurethane resin sheet comprises a first hollow body having an average particle diameter of from 70 μm to 150 μm and a second hollow having an average particle diameter of from 5 μm to 60 μm. body.

<3> The polishing pad according to <1>, wherein the first hollow body and the second hollow body are contained in a mass ratio of 5:95 to 80:20.

The polishing pad according to any one of <1> to <3> wherein the polyurethane resin sheet has a bubble ratio of 20% to 60%.

The polishing pad according to any one of <1> to <4> wherein the polyurethane resin sheet has a density of 0.50 g/cm ³ to 0.80 g/cm ³ .

The polishing pad according to any one of <1> to <5> wherein the polyurethane resin sheet has a D hardness of 20 to 70 degrees.

The polishing pad according to any one of <1> to <6> wherein the polyol component as the urethane resin constituting the polyurethane resin sheet contains a number average molecular weight. It is a polytetramethylene glycol of 500 to 950.

<8> A method of producing a polishing pad according to any one of <1> to <7>, wherein the manufacturing method comprises the steps of: at least a polyamine as a prepolymer The isocyanate-bonded isocyanate compound (A), the curing agent (D), the first hollow body having an average particle diameter of 80 μm to 150 μm, and the second hollow body having an average particle diameter of 5 μm to 60 μm are mixed to obtain a molded body. The polyurethane resin molded article is molded from the mixed solution for molding the molded body to obtain a polyurethane resin sheet.

<9> The method for producing a polishing pad according to <8>, wherein the first hollow body and the second hollow body are included in a mass ratio of 5:95 to 80:20.

The method for producing a polishing pad according to the above aspect, wherein the hardener (D) comprises a compound selected from the group consisting of a polyamine compound (D-1) and a polyol compound (D-2). At least one of the groups, and the active hydrogen group present in the hardener (D) of the polyurethane resin sheet relative to the isocyanate containing a polyurethane bond as a prepolymer The equivalent ratio of the isocyanate groups present at the terminal of the compound (A), that is, the r value is 0.75 to 1.30, and the components are mixed.

The method for producing a polishing pad according to any one of the above aspects, further comprising the step of reacting the polyisocyanate compound (B) with the polyol compound (C) to obtain a pretreatment Said polyurethane-containing polymer The isocyanate compound (A) which is a bond, and the polyol compound (C) contains a polytetramethylene glycol having a number average molecular weight of 500 to 950.

Since the polishing pad of the present invention can concentrate the heat generated during the polishing process in the vicinity of the polishing surface, the polishing surface is easily softened. Therefore, the problem of polishing damage due to foreign matter locally generated during the grinding process can be improved. In addition, the polishing rate can be increased. Moreover, the entire polishing pad can maintain a certain hardness, thereby ensuring a certain flatness and reducing the depression.

Hereinafter, embodiments for carrying out the invention will be described.

<<Grinding pad>>

The polishing pad of the present invention comprises an abrasive layer having a polyurethane resin sheet, the polyurethane resin sheet comprising substantially spherical bubbles, and the polishing pad is characterized in that the polyamine group The formate resin sheet has a thermal conductivity of 0.10 W/(m.k) or less, the polyurethane resin sheet has an initial load of 200 g at 45 ° C, a strain range of 0.1% to 0.5%, and a measurement frequency. The ratio of the loss elastic modulus to the storage elastic modulus in the tensile mode is 1.630 to 0.270, and the compression modulus of the polyurethane resin sheet is 60% to 100. %.

The polyurethane resin sheet means having at least 2 in the molecule A flaky resin having a urethane bond. The polyurethane resin sheet preferably has at least two or more urethane bonds and at least two or more urea bonds in the molecule. The polyurethane resin sheet of the present invention and the polishing pad containing the resin sheet can be produced, for example, according to the production method of the present invention to be described later.

In addition, the substantially spherical shape is a concept of a normal bubble shape (a shape that is isotropic, a spherical shape, an elliptical shape, or a shape close to the shape) existing in a molded body formed by a dry method. The shape of the bubble contained in the molded body formed by the wet method (the structure having anisotropy and having a diameter from the surface of the polishing layer to the bottom of the polishing pad) is clearly distinguished.

(thermal conductivity (W/(m.k)))

In the scope of this specification and the patent application, the so-called thermal conductivity refers to thermal self-grinding. The ease with which the surface is transferred to the inside of the polishing pad.

The measurement of the thermal conductivity can be carried out, for example, by a B-type precision rapid thermal property measuring device (manufactured by KATO TECH Co., Ltd.: THERMO LABO II. KES-F7).

The polyurethane resin sheet in the polishing pad of the present invention has a thermal conductivity of 0.10 W/(m.k) or less, preferably 0.085 W/(m.k) to 0.098 W/(m.k). More preferably, it is 0.095 W/(m.k) to 0.097 W/(m.k).

When the thermal conductivity is within the above range, heat generated during the polishing process is hard to be transmitted from the polishing surface to the inside of the polishing pad, so that it is easy to concentrate heat on the polishing surface. As a result, the polishing surface is softened, and even if foreign matter is locally generated during the polishing process, it is difficult to cause polishing damage.

(tan δ)

In the present specification and the patent application, tan δ is a ratio of the loss elastic modulus to the storage elastic modulus, and is an index indicating the degree of viscosity under a certain temperature condition. The storage elastic modulus is a measure of the energy stored and completely recovered every one cycle when a stress that changes sinusoidally is applied to the foam. On the other hand, the loss elastic modulus refers to the magnitude of the stress component in which the strain at the strain of the sine wave of the applied characteristic frequency is only π/2 phase.

In the scope of this specification and the patent application, the storage elastic modulus and the loss elastic modulus are respectively according to JIS K7244-4, at 45 ° C, the initial load is 200 g, the strain range is 0.1% to 0.5%, and the measurement frequency is 1.6 Hz ( 10 rad/sec), storage elastic modulus and loss elastic modulus in tensile mode. When the surface temperature of the polishing pad when the object to be polished is polished is usually 40 ° C to 50 ° C, the surface state of the pad under the surface temperature of the pad under the polishing condition can be grasped by measuring the tan δ at 45 ° C (the surface of the pad) The degree of stickiness).

In the polishing pad of the present invention, the polyurethane resin molded body constituting the polishing pad has an initial load of 200 g at 45 ° C, a strain range of 0.1% to 0.5%, a measurement frequency of 1.6 Hz, and a loss in a tensile mode. The ratio (tan δ) (loss elastic modulus/storage elastic modulus) of the elastic modulus to the storage elastic modulus is 0.130 to 0.270, preferably 0.130 to 0.160, more preferably 0.135 to 0.150.

When tan δ is in the above range, it has moderate retardation elasticity, and excessive extrusion and excessive follow-up of the unevenness of the workpiece can be suppressed, so that polishing damage is less likely to occur, and the polishing rate is also improved. Moreover, it is also easy to improve the flatness.

(compression elastic modulus)

In the scope of the present specification and the patent application, the compression elastic modulus is an index of the ease of recovery of the compression deformation of the polishing pad.

The compression elastic modulus can be obtained by using a Schopper type thickness measuring device (pressing surface: a circular shape having a diameter of 1 cm) according to Japanese Industrial Standards (JIS L 1021). Specifically, it is as follows.

Since no-load state measured thickness after the initial load is applied 30 seconds t _0, then the state was measured from the thickness t ₀ of the thickness of the final load is applied for 30 seconds t _1. Then, the entire load was removed from the state of the thickness t ₁ and left for 5 minutes (in the no-load state), and the thickness t ₀ ' after the initial load of 30 seconds was measured again. The compression elastic modulus can be calculated by a formula of a compression elastic modulus (%) = 100 × (t ₀ '-t ₁ ) / (t _{0 -} t ₁ ) (in addition, an initial load of 300 g/cm ² , final load) It is 1800 g/cm ² ).

In the polishing pad of the present invention, the polyurethane elastic resin sheet has a compression elastic modulus (%) of 60% to 100%, preferably 65% to 85%, more preferably 65% to 80%.

When the compression elastic modulus is within the above range, the entire polishing pad has moderate elasticity, is difficult to clog, and has improved flatness.

(first hollow body and second hollow body)

In the scope of the present specification and the patent application, the term "hollow body" means a microsphere having a void.

In the polishing pad of the present invention, the polyurethane resin sheet preferably comprises a first hollow body having an average particle diameter of 70 μm to 150 μm and a second hollow body having an average particle diameter of 5 μm to 60 μm. The average particle diameter of the first hollow body is more preferably 80 μm to 140 Μm, particularly preferably from 90 μm to 130 μm, particularly preferably from 90 μm to 110 μm. The average particle diameter of the second hollow body is more preferably from 8 μm to 55 μm, still more preferably from 10 μm to 50 μm, particularly preferably from 10 μm to 30 μm.

By including the first hollow body and the second hollow body, the thermal conductivity of the polyurethane resin sheet can be efficiently reduced. Therefore, the heat generated during the polishing process is concentrated in the vicinity of the polishing surface, and the vicinity of the polishing surface is softened. Therefore, even if foreign matter is locally generated during the polishing process, it is difficult to cause polishing damage.

Preferably, the mass of the first hollow body and the second hollow body is 5:95 to 80:20, more preferably 10:90 to 70:30, and particularly preferably 20:80 to 60:40, and further Good for 30:70~60:40, especially good for 40:60~60:40, best for 50:50~50:50.

When the mass ratio of the first hollow body to the second hollow body is within the above range, the amount of slurry held can be secured, and the polishing rate can be improved. In addition, it is also difficult to cause abrasive damage.

(bubble rate)

In the scope of the present specification and the patent application, the bubble ratio refers to the void ratio in the polishing pad. The bubble ratio can be measured in accordance with the density of the obtained polyurethane resin sheet and the density of the polyurethane resin.

In the polishing pad of the present invention, the cell ratio of the polyurethane resin sheet is preferably from 20% to 60%, more preferably from 30% to 50%, particularly preferably from 40% to 50%.

When the bubble ratio is within the above range, the slurry is smoothly accumulated and supplied to the void portion of the hollow body opened on the polishing surface.

(density)

The density (bulk density) of the polyurethane resin sheet is preferably from 0.50 g/cm ³ to 0.80 g/cm ³ , more preferably from 0.55 g/cm ³ to 0.75 g/cm ³ , and particularly preferably 0.60. g/cm ³ ~0.70g/cm ³ . When the density is within the above range, it is also difficult to cause damage due to clogging of the surface of the polishing layer due to processing of the abrasive or the workpiece of the object to be polished.

(D hardness)

In the present specification and the patent application, the D hardness refers to a value measured in accordance with JIS K7311.

The D hardness of the polyurethane resin sheet is preferably 70 degrees or less, more preferably 20 degrees to 60 degrees, and particularly preferably 35 degrees to 45 degrees.

If the D hardness is within the above range, the polishing pad has moderate elasticity, so the planarization performance is improved, and the generation of scratches can be reduced.

(Compression ratio)

In the scope of the present specification and the patent application, the compression ratio refers to an index of the flexibility of the polishing pad.

The compression ratio can be obtained by using a Xiaobo-type thickness measuring device (pressing surface: a circular shape having a diameter of 1 cm) according to Japanese Industrial Standards (JIS L 1021). Specifically, it is as follows.

Since no-load state measured thickness after the initial load is applied 30 seconds t _0, then the state was measured from the thickness t ₀ of the thickness of the final load is applied for 30 seconds t _1. The compression ratio can be calculated by a formula of a compression ratio (%) = 100 × (t _{0 -} t ₁ ) / t ₀ (in addition, an initial load of 300 g/cm ² and a final load of 1800 g/cm ² ).

The compression ratio (%) of the polishing pad of the present invention is preferably from 0.1% to 5%, more preferably from 0.5% to 3%, still more preferably from 0.8% to 1.5%. When the compression ratio is within the above range, the flatness of the object to be polished can be improved.

(thickness)

The thickness of the polyurethane resin sheet in the polishing pad of the present invention is not particularly limited, and can be used, for example, in the range of 0.5 mm to 3.0 mm, preferably 0.5 mm to 1.5 mm.

(Composition of polyurethane resin)

In the present specification and the scope of the patent application, the constituent component of the polyurethane resin refers to a polyamine group which is incorporated as a part of a chain constituting the polyurethane resin by a subsequent polymerization reaction. The raw material component of the formate resin.

The constituent components of the polyurethane resin constituting the polyurethane resin sheet of the polishing pad of the present invention include a raw material component of the polyurethane resin, that is, a polyisocyanate component and a polyol component. And a polyamine component as an optional component. The polyisocyanate component (B) polyisocyanate compound mentioned later is mentioned. Examples of the polyol compound include a polyol compound which can be used after the (C) polyol compound and the (D-2) prepolymer are synthesized. The polyamine component (D-1) polyamine compound is mentioned.

The polyurethane resin sheet in the polishing pad of the present invention preferably contains a polytetramethylene glycol having a number average molecular weight of 500 to 950 as a polyol component constituting the polyurethane resin. The number average molecular weight of the polytetramethylene glycol is preferably from 600 to 900, particularly preferably from 700 to 900.

The polishing pad of the present invention can be preferably used for polishing of a glass substrate for a crucible, a hard disk, a mother glass for a thin liquid crystal display, a semiconductor wafer, a semiconductor device, or the like, in particular, a chemical mechanical polishing (CMP) of a semiconductor device.

<<Method of manufacturing polishing pad>>

The polishing pad of the present invention can be obtained, for example, by the production method of the present invention. The production method of the present invention is characterized by comprising the steps of: at least a polyurethane-containing isocyanate compound (A) as a prepolymer, a curing agent (D), and an average particle diameter of 70 μm to 150 μm. 1 hollow body, a second hollow body having an average particle diameter of 5 μm to 60 μm, to obtain a mixed liquid for molding a molded body (mixing step); and forming a polyurethane resin from the mixed liquid for forming the molded body The body is molded to obtain a polyurethane resin sheet (former forming step).

Hereinafter, each step will be described.

<mixing step>

In the mixing step, at least a polyurethane bond-containing isocyanate compound (A), a hardener (D), a first hollow body, and a second hollow body are mixed as a raw material of the polyurethane resin sheet. . Further, components other than the above may be used in combination within a range not impairing the effects of the present invention.

Hereinafter, each component will be described.

[(A) Isocyanate Compound Containing Polyurethane Bond]

The polyurethane bond-containing isocyanate compound (A) (hereinafter sometimes referred to as (A) component) as a prepolymer is obtained by using the following polyisocyanate compound (B) and polyol compound (C) The compound obtained by the reaction under the usual conditions is A person having a polyurethane bond and an isocyanate group in the molecule. Further, other components may be contained in the isocyanate compound containing a polyurethane bond within a range not impairing the effects of the present invention.

As the isocyanate compound (A) containing a polyurethane bond, a commercially available product may be used, or a compound obtained by reacting a polyisocyanate compound with a polyol compound may be used. The reaction is not particularly limited as long as the addition polymerization reaction is carried out by using a known method and conditions in the production of the polyurethane resin. For example, it can be produced by adding a polyisocyanate compound heated to 50 ° C while stirring in a polyol compound heated to 40 ° C under a nitrogen atmosphere, and then raising the temperature to 80 ° C after 30 minutes, followed by 80 The reaction was carried out at ° C for 60 minutes.

[(B) Polyisocyanate Compound]

In the present specification and the patent application, the polyisocyanate compound means a compound having two or more isocyanate groups in the molecule.

The polyisocyanate compound (B) (hereinafter sometimes referred to as the component (B)) is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, as the diisocyanate compound having two isocyanate groups in the molecule, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), and 2,4-toluene diisocyanate are mentioned. (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenation) MDI), 3,3'-dimethoxy-4,4'-biphenyldiisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylene-1,4 -diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propyl group -1,2-diisocyanate, butyl-1,2-diisocyanate, cyclohexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, p-phenylene isothiocyanate, Xylene-1,4-diisothiocyanate, ethylene diisothiocyanate, and the like.

As the polyisocyanate compound, a diisocyanate compound is preferable, and more preferably 2,4-TDI, 2,6-TDI, MDI, particularly preferably 2,4-TDI or 2,6-TDI.

The polyisocyanate compound may be used singly or in combination of a plurality of polyisocyanate compounds.

[(C) Polyol Compound]

In the present specification and the patent application, the term "polyol compound" means a compound having two or more alcoholic hydroxyl groups (OH) in the molecule.

The polyol compound (C) (hereinafter sometimes referred to as a component (C)) used in the synthesis of a polyurethane bond-containing isocyanate compound as a prepolymer may, for example, be ethylene glycol or diethylene glycol. a diol compound such as (DEG) or butanediol, a triol compound or the like; a polyether polyol compound such as poly(oxytetramethylene) glycol (PTMG); a reaction product of ethylene glycol with adipic acid or dibutyl A polyester polyol compound such as a reactant of an alcohol and adipic acid; a polycarbonate polyol compound, a polycaprolactone polyol compound, or the like. Further, a trifunctional propylene glycol obtained by adding ethylene oxide can also be used. Among them, PTMG is preferred, and PTMG and DEG are preferably used in combination. The number average molecular weight (Mn) of PTMG is preferably from 500 to 950, more preferably from 600 to 900, and particularly preferably from 700 to 900. The number average molecular weight can be determined by Gel Permeation Chromatography (GPC). In addition, when the number average molecular weight of the polyol compound is measured from the polyurethane resin, it may also be After decomposing the components, the method is estimated by GPC.

The polyol compound (C) may be used singly or in combination of a plurality of polyol compounds.

(NCO equivalent of prepolymer)

In addition, "(parts by mass of polyisocyanate compound (B) + parts by mass of polyol compound (C)) / [(number of functional groups per molecule of polyisocyanate compound (B) × mass of polyisocyanate compound (B)) (molecular weight of the polyisocyanate compound (B)) - (the number of functional groups per molecule of the polyol compound (C) × the mass part of the polyol compound (C) / the molecular weight of the polyol compound (C)) The NCO equivalent of the prepolymer is a value indicating the molecular weight of PP (prepolymer) with respect to one NCO group. The NCO equivalent is preferably from 200 to 800, more preferably from 400 to 750, particularly preferably from 450 to 700, and particularly preferably from 500 to 700.

[(D) hardener]

In the production method of the present invention, a hardener (also referred to as a chain extender) is mixed with an isocyanate compound containing a polyurethane bond or the like in the mixing step. By adding a hardener, in the subsequent molding step of molding, the main chain end of the polyurethane bond-containing isocyanate compound as a prepolymer is bonded to a hardener to form a polymer chain, and hardens. .

As the hardener, for example, a polyamine compound and/or a polyol compound can be used.

((D-1) polyamine compound)

In the present specification and the patent application, the polyamine compound refers to a compound having two or more amine groups in the molecule.

As the polyamine compound (D-1) (hereinafter sometimes referred to as a component (D-1)), an aliphatic or aromatic polyamine compound, particularly a diamine compound can be used, and examples thereof include ethylenediamine and propylene. Diamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (Methylene bis-o-chloroaniline) (hereinafter abbreviated as MOCA), a polyamine compound having the same structure as MOCA, and the like. Further, the polyamine compound may have a hydroxyl group, and examples of such an amine compound include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, and 2-hydroxyethyl propylene diamine, 2-hydroxypropyl ethylene diamine, di-2-hydroxypropyl ethylene diamine, and the like.

The polyamine compound is preferably a diamine compound, more preferably MOCA, diaminodiphenylmethane or diaminodiphenylphosphonium, and particularly preferably MOCA.

The polyamine compound (D-1) may be used singly or in combination of a plurality of polyamine compounds (D-1).

The polyamine compound (D-1) is preferably mixed with other components and/or in order to improve the uniformity of the bubble diameter in the subsequent molded body forming step, it is preferred to carry out the removal under reduced pressure in a heated state as needed. bubble. As the defoaming method under reduced pressure, a known method may be used for the production of the polyurethane, and for example, defoaming may be performed using a vacuum pump at a degree of vacuum of 0.1 MPa or less.

When a solid compound is used as a curing agent (chain extender), it can be defoamed under reduced pressure while being melted by heating.

((D-2) Polyol compound which can be used after prepolymer synthesis)

Further, in the present invention, it is used to form an isocyanate as the prepolymer. The polyol compound (C) of the acid ester group compound is different, and the polyol compound (D-2) can be used as a hardener.

The polyol compound (D-2) can be used without particular limitation as long as it is a compound such as a diol compound or a triol compound. Further, it may be the same as or different from the polyol compound (C) for forming the prepolymer.

Specific examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,3-butylene glycol, and 1,4-butanediol. Low molecular weight diols such as pentanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, polytetramethylene glycol, polyethylene glycol, polypropylene glycol, etc. High molecular weight polyol compounds and the like.

The polyol compound (D-2) may be used singly or in combination of a plurality of polyol compounds (D-2).

As the hardener (D), a polyamine compound (D-1) can be used, and a polyol compound (D-2) can also be used, and the mixture can also be used. Among them, the polyamine compound (D-1) is preferably used.

(r value)

In the method for producing a polishing pad of the present invention, it is preferred that the active hydrogen group (amine group and hydroxyl group) present in the hardener (D) is relative to the isocyanate containing a polyurethane bond as a prepolymer. The equivalent ratio of the isocyanate groups present at the terminal of the compound (A), that is, the r value is 0.70 to 1.30, and the components are mixed, and the r value is more preferably 0.75 to 1.20, particularly preferably 0.80 to 1.10.

When the r value is within the above range, the occurrence of polishing damage can be reduced, and a polishing pad excellent in polishing speed or flatness can be easily obtained.

[(E) First hollow body and second hollow body]

In the method for producing a polishing pad of the present invention, the first hollow body and the second hollow body are used, and the cells are enclosed in the inside of the polyurethane resin molded body.

The hollow body refers to a microsphere having a void. The microspheres include: a spherical shape, an elliptical shape, and a shape close to the shape. Examples of the hollow body include those in which an outer casing (polymer shell) containing a thermoplastic resin and an unexpanded heat-expandable microsphere having a low boiling point hydrocarbon contained in the outer shell are heated and expanded.

As the polymer shell, as disclosed in Japanese Laid-Open Patent Publication No. SHO 57-137323, for example, an acrylonitrile-vinylidene chloride copolymer, an acrylonitrile-methyl methacrylate copolymer, or a vinyl chloride can be used. - a thermoplastic resin such as an ethylene copolymer. Also, as the low boiling point hydrocarbon contained in the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether or the like can be used.

In the method for producing a polishing pad of the present invention, a first hollow body having an average particle diameter of 70 μm to 150 μm and a second hollow body having an average particle diameter of 5 μm to 60 μm are used. The preferred average particle diameter of the first hollow body and the second hollow body or the mass ratio thereof is as described above.

Examples of the first hollow body include Matsumoto microspheres F-80DE (manufactured by Matsumoto Oil & Fats Co., Ltd.) (which is an acrylonitrile-based shell composition, and has an average particle diameter of 90 μm to 130 μm and a density of 20 kg/m ³ ± 5 kg. /m ³ of expanded micro hollow spheroids).

Examples of the second hollow body include EXPANCEL 461DE20d70 (manufactured by EXPANCEL), which is a shell composition of a vinylidene chloride-acrylonitrile system, an average particle diameter of 10 μm to 50 μm, and a density of 67 kg. /m ³ ±7 kg/m ³ of expanded micro hollow spheroids).

Further, the average particle diameter can be measured by a laser diffraction type particle size distribution measuring apparatus (for example, Spectris (manufactured by Spectris), Mastersizer 2000).

It is preferably 1 part by mass to 14 parts by mass, more preferably 2 parts by mass to 14 parts by mass, even more preferably 3 parts by mass to 14 parts by mass, based on 1000 parts by mass of all the components constituting the prepolymer. The first hollow body was added.

It is preferably 1 part by mass to 48 parts by mass, more preferably 2 parts by mass to 45 parts by mass, even more preferably 4 parts by mass to 40 parts by mass, based on 1000 parts by mass of all the components constituting the prepolymer. A second hollow body is added.

Further, in addition to the above-described components, the foaming agent previously used may be used in combination with the minute hollow spheres, or the components may be blown in the mixing step described below, without impairing the effects of the present invention. Non-reactive gas. The foaming agent may, for example, be water or a foaming agent containing a hydrocarbon having 5 or 6 carbon atoms as a main component. Examples of the hydrocarbons include chain hydrocarbons such as n-pentane and n-hexane, and alicyclic hydrocarbons such as cyclopentane and cyclohexane.

Further, a known foam stabilizer, a flame retardant, a colorant, a plasticizer or the like may be added in addition to the above components.

In the mixing step, at least the polyurethane-containing isocyanate compound (A), the curing agent (D), the first hollow body, and the second hollow body, which are prepolymers, are supplied to the mixer and stirred. mixing. The order of mixing is not particularly limited, and it is preferred that the isocyanate compound (A) containing the polyurethane linkage be mixed with the first hollow body and the second hollow body in advance, and it may be combined with the hardener (D) or Need it His ingredients are supplied to the mixer. In this manner, a mixed liquid for molding a shaped body was prepared. The mixing step is carried out while heating to a temperature at which the fluidity of the respective components can be ensured.

For example, the hardener can be put into a jacket with adjustable temperature in a prepolymer (isocyanate containing polyisocyanate) solution containing the hollow body heated to 30 ° C to 90 ° C. In the mixer, stirring was carried out at 30 ° C to 130 ° C. The mixture may be added to the jacketed tank with a mixer for aging as needed. The stirring time is appropriately adjusted depending on the number of teeth of the mixer, the number of revolutions, the gap, and the like, and is, for example, 1 second to 60 seconds.

<Forming body forming step>

In the molding step, the polyurethane molding resin is formed by flowing the mixture for molding a molded body prepared in the mixing step into a mold frame of 30° C. to 100° C. to be cured. In this case, the polyurethane and the curing agent are reacted to form a polyurethane resin, and the mixed liquid is substantially uniformly dispersed in the resin in the first hollow body and the second hollow body. Harden. Thereby, a polyurethane molding having a large number of substantially spherical bubbles is formed.

The polyurethane resin molded body obtained by the above-described molded body forming step is then cut into a sheet to form a polyurethane resin sheet. An opening is provided on the surface of the sheet by slicing. At this time, in order to form an opening of the surface of the polishing layer which is excellent in abrasion resistance and which is difficult to be clogged, it can be aged at 30 ° C to 120 ° C for about 1 hour to 24 hours.

The thus-obtained polishing layer having a polyurethane resin sheet, and then a double-sided tape is attached to the surface of the polishing layer opposite to the polishing surface, and cut into a special layer. The shape is preferably a disk shape, thereby completing the polishing pad of the present invention. The double-sided tape is not particularly limited and can be arbitrarily selected from the double-sided tape known in the art.

Further, the polishing pad of the present invention may have a single layer structure including only the polishing layer, and may include a plurality of layers in which another layer (lower layer, support layer) is bonded to the surface of the polishing layer opposite to the polishing surface. The characteristics of the other layer are not particularly limited, and it is preferred to bond a layer which is softer than the polishing layer (having a small A hardness or a small D hardness) on the surface opposite to the polishing layer. The polishing flatness is further improved by providing a layer which is softer than the abrasive layer.

When the multilayer structure is used, it is sufficient to use a double-sided tape, an adhesive, or the like, and press and fix a plurality of layers while pressing each other as needed. The double-sided tape or the adhesive to be used at this time is not particularly limited, and can be arbitrarily selected from double-sided tapes or adhesives known in the art.

Moreover, the polishing pad of the present invention may be subjected to grinding treatment on the surface and/or the back surface of the polishing layer as needed, or performing groove processing or embossing processing or hole processing (punching processing) on the surface, or may be a substrate and/or a substrate and/or The adhesive layer is bonded to the polishing layer, and may also have a light transmitting portion.

The method of the grinding treatment is not particularly limited, and the grinding can be carried out by a known method. Specifically, grinding by sandpaper can be cited.

The shape of the groove processing and the embossing is not particularly limited, and examples thereof include a lattice shape, a concentric shape, and a radial shape.

When the polishing pad of the present invention is used, the polishing pad is attached to the polishing plate of the grinder so that the polishing surface of the polishing layer faces the object to be polished. Then one While the polishing slurry is supplied, the polishing plate is rotated to polish the surface of the workpiece.

Examples of the object to be polished which are processed by the polishing pad of the present invention include a glass substrate for a hard disk, a mother glass for a thin display, a semiconductor wafer, and a semiconductor device. Among them, the polishing pad of the present invention is preferably used for chemical mechanical polishing (CMP) processing of a semiconductor device.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples, but the invention should not be construed as limited.

In each of the examples, the comparative examples, and the tables 1 to 5, "parts" means "parts by mass" unless otherwise specified.

In addition, each abbreviation of Table 1 - Table 2 means the following components.

. PTMG: poly(oxytetramethylene) glycol

. DEG: Diethylene glycol

. 2,4-TDI: 2,4-toluene diisocyanate

. MOCA: 4,4'-methylenebis(2-chloroaniline)

The first hollow body: a micro hollow spheroid having an average particle diameter of 93.6 μm and a density of 20 kg/m ³ ± 5 kg/m ³ (trade name: Matsumoto microsphere F-80DE (manufactured by Matsumoto Oil Co., Ltd.))

The second hollow body: average particle diameter 21.0μm, a density of 67kg / m ³ ± 7kg / m ³ tiny hollow spheroids (trade name: EXPANCEL461DE20d70 (Ak Spencer Road Corporation))

In addition, the NCO equivalent is represented by "(mass (parts) of polyisocyanate compound + mass (parts) of polyol compound (C)) / [(number of functional groups per molecule of polyisocyanate compound × polyisocyanate compound) Mass (parts) / molecular weight of the polyisocyanate compound) - (the number of functional groups per molecule of the polyol compound (C) × the mass (parts) of the polyol compound (C) / the molecular weight of the polyol compound (C)) The value of the molecular weight of the prepolymer (PP) relative to one NCO group was determined.

The r value is a numerical value indicating the equivalent ratio of the active hydrogen group (amine group and hydroxyl group) present in the curing agent to the terminal isocyanate group in the prepolymer as described above.

<Example 1>

In Example 1, as the prepolymer of the first component, poly(oxytetramethylene) glycol having 400 parts of 2,4-toluene diisocyanate (2,4-TDI) and a number average molecular weight of about 650 was used. (PTMG) 519 parts, diethylene glycol (DEG) 81 parts obtained, the isocyanate content is a terminal isocyanate group-containing urethane prepolymer having an NCO equivalent of 681, which is heated to 55 ° C, in which 12 parts of Matsumoto microspheres F-80DE and 12 parts of EXPANCEL461DE20d70 were added, and defoaming was carried out under reduced pressure. The MOCA of the second component was melted at 120 ° C and defoamed under reduced pressure. The first component and the second component were mixed so that the r value became 1.21, and the obtained mixed solution was cast into a mold box preheated to 100 ° C for 30 minutes, and then the formed polyurethane was formed. The foam is drawn from the mold frame. The foam was cut into a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

<Example 2 and Comparative Example 1 to Comparative Example 2>

The polishing pads of Example 2 and Comparative Example 1 to Comparative Example 2 were produced in the same manner as in Example 1 except that the number average molecular weight (Mn) of the PTMG was changed as shown in Table 1.

<Example 3 to Example 4 and Comparative Example 3 to Comparative Example 4>

The polishing pads of Examples 3 to 4 and Comparative Examples 3 to 4 were produced in the same manner as in Example 2 except that the amount of the curing agent was changed as shown in Table 2.

<Example 5 to Example 8 and Comparative Example 5 to Comparative Example 6>

In the same manner as in the second embodiment, the fifth to eighth embodiments were produced in the same manner as in the second embodiment, except that the mass ratio of the first hollow body to the second hollow body was changed as shown in Tables 3 to 4. The polishing pads of Comparative Examples 5 to 6 were used. In order to eliminate the influence on the effect due to the difference in the bubble ratio between the examples and the comparative examples, the first hollow body and the second hollow body were changed so that the bubble ratios of the respective examples and the comparative examples were substantially fixed. Quality ratio.

<Comparative Example 7>

In Comparative Example 7, a commercially available polishing pad (trade name: IC1000 (registered trademark), manufactured by Nita Haas Co., Ltd.) was used.

<Comparative Example 8>

In Comparative Example 8, according to Example 1 of Japanese Patent No. 3013105, 1000 parts of Adiprene L325 (NCO equivalent of 466) was used, which was heated to 55 ° C, and EXPANCEL 551 DE 40d42 (which is a vinylidene chloride-acrylonitrile type) was added thereto. 20 parts of the expanded micro hollow spheroids having a shell composition of 40.9 μm and a density of 42 kg/m ³ ± 4 kg/m ³ were subjected to defoaming under reduced pressure. The MOCA of the second component was melted at 120 ° C and defoamed under reduced pressure. The first component and the second component were mixed so that the r value became 0.90, and the obtained mixed solution was cast into a mold box preheated to 100 ° C for 30 minutes, and then the formed polyurethane was formed. The foam is drawn from the mold frame. The foam was cut into a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

<Example 9>

In the same manner as in Comparative Example 8, except that 9 parts of Matsumoto microspheres F-80DE (first hollow body) and 10 parts of EXPANCEL 461DE20d70 (second hollow body) were used as the hollow body. A urethane sheet was made and a polishing pad was obtained. In addition, in order to eliminate the influence on the effect due to the difference in the bubble ratio in Example 9 and Comparative Example 8, the first hollow body and the second type were changed so that the bubble ratios of Example 9 and Comparative Example 8 were substantially constant. The mass ratio of the hollow body.

<Example 10>

In Example 10, the prepolymer as the first component was obtained by reacting propylene glycol added with ethylene oxide with diphenylmethane-4,4'-diisocyanate (MDI) to have an NCO equivalent of 236. A urethane prepolymer containing a terminal isocyanate group (manufactured by Dainippon Ink and Chemicals, Inc., trade name: PANDEX TM-227), which is heated to 60 ° C, in which 12 parts of Matsumoto microspheres F-80DE and 12 parts of EXPANCEL461DE20d70 were added, and defoaming was carried out under reduced pressure. The second component uses a mixture of low molecular diols and hydroxyl content The chain extender of 68 (manufactured by Dainippon Ink Chemical Co., Ltd., trade name: PANDEX TM-228) was kept at 40 ° C, and defoamed under reduced pressure. The first component and the second component were mixed so that the r value became 0.95, and the obtained mixed solution was cast until it was preheated to a mold frame of 70 ° C for 60 minutes, and then the formed polyurethane was formed. The foam is drawn from the mold frame. The foam was subjected to secondary curing at 70 ° C for 10 hours, and cut into a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

<physical property>

For each of the above examples and comparative examples, thermal conductivity (W/m.k), tan δ, compressive elastic modulus (%), bubble ratio (volume fraction) (%), and density (g/cm) were calculated or measured. ³ ), D hardness (°), compression ratio (%), thickness (mm). The results are shown in Tables 6 to 9.

In addition, the measurement method of each item is as follows.

(thermal conductivity (W/m.k))

Each of the sheets of Examples 1 to 10 and Comparative Examples 1 to 8 was placed on a constant temperature stage maintained at 20 ° C by a water bath cooling, and the power consumption required to maintain the temperature of the heat source stage at 30 ° C was measured. (heat flow loss, W). For the measurement device, a type B precision rapid thermal property measuring device (trade name: THERMO LABO II. KES-F7 (manufactured by Jado Technology Co., Ltd.)) was used. The measurement conditions were such that the temperature was 20 ° C, the relative humidity was 65 ° C, the load was 6 g/cm ² , and the contact area (hot plate area) was 50 mm × 50 mm.

The thermal conductivity can be obtained by heat flow loss (W) × thickness (m) ÷ (hot plate area (m ² ) × temperature difference (° C) of the sample surface).

(tan δ (45 ° C))

The storage elastic modulus (MPa) was measured by RSAIII of TA Instruments (TA Instruments. Japan) according to JIS K7244-4, with an initial load of 200 g, a strain range of 0.1% to 0.5%, and a measurement frequency of 10 rad/sec. 1.6 Hz), and the temperature increase rate was 5.0 ° C / min, and the storage elastic modulus, loss elastic modulus, tan δ of the test piece of 10 mm × 5 mm at 45 ° C when the temperature was raised from 20 ° C to 100 ° C was measured. In addition, detailed conditions are as follows.

Measuring device: Japan TA Instruments RSAIII

Test direction: stretching

Test piece: 10mm × 5mm

Load: 200g

Strain: 0.1%~0.5%

Frequency: 10 rad/sec = 1.6 Hz

Temperature: 20 ° C ~ 100 ° C

Sample thickness: measured by a thickness gauge (set to no groove)

(bubble rate (%))

The volume was calculated from the average of the thicknesses of 5 points (angle 4 points + 1 point) of 10 cm square. The weight of the sample was measured and divided by the obtained volume, thereby calculating the density of the sample. Then, the density of the polyurethane resin was set to 1.2 g/cm ³ , and the bubble ratio was calculated by the following formula.

Bubble rate = {1 - (density of sample / 1.2)} × 100

(bulk density)

The bulk density (g/cm ³ ) was calculated by measuring the weight (g) of a sample cut into a specific size and obtaining a volume (cm ³ ) from the size.

(D hardness)

The D hardness is measured by the Japanese Industrial Standard (JIS K 7311), and the D hardness tester (trade name "GS-702N", manufactured by TECLOCK Co., Ltd.) prescribed by JIS K 7215 is used for the hardness tester. In addition, the sample was prepared by laminating five urethane sheets (thickness: about 1.3 mm) described in the comparative examples and the examples, and was set so that the total thickness was at least 6 mm.

(compression ratio (%) and compressive elastic modulus (%))

The compression ratio and the compression elastic modulus were determined in accordance with JIS-L1021 using a Shaw-type thickness measuring device (pressure surface: a circle having a diameter of 1 cm). Specifically, at room temperature, measured from the no load is applied the initial load thickness after pressing for 30 seconds to t ₀ of the initial load, and then a pressure is applied from the final state of a thickness of t _0, the load measured in the original The thickness t ₁ after placing it for 1 minute. After the turn, since the thickness t ₁ of the state of the load was completely removed, stand for 5 minutes, the thickness was measured again after the initial load is applied for 30 seconds t ₀ '. Based on the values, the compression ratio and the compression elastic modulus compression ratio (%) = (t _{0 -} t ₁ ) / t ₀ × 100 are calculated based on the following equations.

The compression elastic modulus (%) = (t ₀ '-t ₁ ) / (t _{0 -} t ₁ ) × 100.

Further, the initial load was set to 300 g/cm ² and the final load was set to 1800 g/cm ² .

<grinding test>

The polishing pads of the respective examples and comparative examples were subjected to polishing treatment under the following polishing conditions, and the polishing rate, the number of polishing damages, and the depth of depression were measured. As the object to be polished, a substrate in which an ethylene oxide is formed into an insulating film by chemical vapor deposition (CVD) on a 12-inch germanium wafer to a thickness of 1 μm was used.

(grinding speed)

The polishing rate is expressed by the thickness (Å) per minute, and the average thickness of the insulating film of the substrate before and after the polishing is determined based on the thickness measurement of each of the 17 portions. value. Further, the thickness measurement was carried out by a Doppler beam sharpening (DBS) mode of an optical film thickness film measuring instrument (KLA-Tencor Co., Ltd., ASET-F5x).

(the number of grinding damages)

For the number of polishing damages, 25 substrates were polished, and the 20th and 25th substrates after the polishing were processed by the optical film thickness film tester (ASET-F5x, manufactured by Kelei Co., Ltd.). The pattern was measured, and the number of occurrences of polishing damage on the surface of the substrate was determined.

(depression depth)

The depth of the depression was measured by a fine shape measuring instrument (manufactured by Kelei Co., Ltd., P-16+) to measure the depression (L/S = 100 μm) = the step of the polished wafer.

In addition, the polishing conditions used in the test are as follows.

. Using a grinder: manufactured by Ebara Seisakusho Co., Ltd., model "F-REX300"

. Grinding head: manufactured by Ebara Seisakusho Co., Ltd., model "GII"

. Grinding pad diameter: 740mmΦ

. Speed: (platen) 70rpm, (top ring) 71rpm

. Grinding pressure: 220hPa

. Abrasive: manufactured by Cabot Company Product Code: SS-25.2 times dilution (using SS25 stock solution: pure water = 1:1 mixture)

. Abrasive temperature: 20 ° C

. Abrasive spray amount: 200ml/min

. Use of workpiece (abrasive): by CVD on a 12-inch Φ 矽 wafer A substrate in which an epoxy film is formed of tetraethoxy decane in a thickness of 1 μm

. Grinding time: 60 seconds / each time

. pad. Applicable conditions: 30N×30 minutes, diamond dresser #250 (A-188 made by 3M), the rotation speed is 54rpm, the plate rotation speed is 80rpm, and the ultra-pure water supply is 200mL/min.

. Grinding conditions: plate rotation speed of 70 rpm, grinding head rotation speed of 71 rpm, grinding slurry flow rate of 200 mL/min, grinding time of 1 minute, and grinding pressure of 2.5 psi (1.7 × 10 ⁴ Pa)

The results of the polishing test using the above method for each of the examples and the comparative examples are shown in Tables 6 to 9.

Regarding the polishing rate, 1650 (Å/min) or more was evaluated as A, 1600 or more to less than 1650 (Å/min) was evaluated as B, and less than 1600 (Å/min) was evaluated as C.

Regarding the number of polishing damages, less than 290 (one) was evaluated as A, less than 300 to 290 or more was evaluated as B, and 300 or more was evaluated as C.

Regarding the depth of the depression, the larger the numerical value, the more the depression is formed, and the flatness is worse. Therefore, it is evaluated as A by less than 48.0 (nm), B as B by 48.0 or more and less than 50.0 (nm), and 50.0 (nm) or more as C.

Further, in the case of the polishing rate, the number of polishing damages, and the depth of the depression, none of the three (all three are A or B) are evaluated as preferred examples (embodiments), and in the present invention, One or more Cs were evaluated as less favorable (comparative examples).

(Test Results 1 (Examples 1 to 2 and Comparative Examples 1 to Comparative Examples) 2))

In the polishing pads of Comparative Example 1 and Comparative Example 2, tan δ was small, and a large amount of polishing damage occurred, which was also inferior in terms of polishing rate and flatness. On the other hand, in the polishing pads of Examples 1 to 2, the tan δ is in the range of 0.130 to 0.270, the thermal conductivity is 0.10 W/(m.k) or less, and the compression elastic modulus is 60% to 100%. Therefore, the polishing damage is small, and the polishing speed or flatness is also excellent.

(Test Results 2 (Examples 3 to 4 and Comparative Examples 3 to 4))

In the polishing pad of Comparative Example 3, tan δ was small, and a large amount of polishing damage occurred, which was also inferior in terms of polishing speed and flatness. Further, in the polishing pad of Comparative Example 4, although tan δ is within the range of the present invention, the compression elastic modulus is small, so that a large amount of polishing damage is generated and the flatness is also poor. On the other hand, in the polishing pads of Examples 3 to 4, the tan δ is in the range of 0.130 to 0.270, the thermal conductivity is 0.10 W/(m.k) or less, and the compression elastic modulus is 60% to 100%. Therefore, the polishing damage is small, and the polishing speed or flatness is also excellent.

(Test Results 3 (Example 2, Example 5 to Example 8 and Comparative Example 5 to Comparative Example 6))

In the second embodiment, the fifth embodiment, the eighth embodiment, the comparative example 5, and the comparative example 6, the ratio of the first hollow body and the second hollow body was changed, and the polishing rate was evaluated. Grind damage, depth of depression.

As a result, in the polishing pads of Comparative Example 5 and Comparative Example 6, the thermal conductivity was high, and a large amount of polishing damage occurred. Further, in the polishing pad of Comparative Example 5, since tan δ was also small, Therefore, the grinding speed is also poor. On the other hand, in the polishing pads of Example 2 and Examples 5 to 8, the tan δ was in the range of 0.130 to 0.270, the thermal conductivity was 0.10 W/(m.k) or less, and the compression elastic modulus was 60. %~100%, so the grinding damage is small, and the polishing speed or flatness is also excellent.

(Test result 4 (Example 9 to Example 10 and Comparative Example 7 to Comparative Example 8))

As a result of the test result 1 to the test result 3, it is judged that the tan δ, the thermal conductivity, and the compression elastic modulus are set to a specific range, and it is possible to obtain a polishing pad which is less likely to cause polishing damage and which is excellent in polishing rate or depression. Therefore, the same test was carried out by changing the kind of the resin. Specifically, the IC 1000 (registered trademark) (manufactured by Nitagase Co., Ltd., including a hollow body) (Comparative Example 7) and the production method described in Example 1 of Japanese Patent No. 3013105 are manufactured. a polishing pad (Comparative Example 8), a polishing pad manufactured according to the production method described in Example 1 of Japanese Patent No. 3013105, and a polishing pad (Comparative Example 9), and the same as Example 1 except that two types of hollow bodies having different sizes are used. ~In Example 8, a polishing pad made of a different resin (Example 10) was evaluated for polishing rate, polishing damage, and dent.

As a result, in Comparative Example 7 and Comparative Example 8, since the thermal conductivity was high and tan δ was also small, a large amount of polishing damage occurred. In addition, the polishing rate was also small, and large depressions were observed and the flatness was also poor. On the other hand, in the polishing pads of Examples 9 to 10, the tan δ was in the range of 0.130 to 0.270, the thermal conductivity was 0.10 W/(m.k) or less, and the compression elastic modulus was 60% to 100%. Therefore, the grinding damage is small, and the polishing speed or the depression is also excellent. According to the results, it is determined that the effect of the present invention is changed even if the kind of the resin is changed. It can also be obtained by setting tan δ, thermal conductivity, and compression elastic modulus within the range of the present invention.

[Industrial availability]

The polishing pad of the present invention can concentrate the heat generated during the polishing process in the vicinity of the polishing surface, so that the polishing surface is easily softened. Therefore, the problem of polishing damage due to foreign matter generated locally during the grinding process can be improved. In addition, the polishing rate can be increased. Moreover, the entire polishing pad can maintain a certain hardness, thereby ensuring a certain flatness and reducing the depression. Therefore, the polishing pad of the present invention and the method of manufacturing the same have industrial applicability.

Claims (11)

A polishing pad comprising an abrasive layer having a polyurethane resin sheet, the polyurethane resin sheet comprising substantially spherical bubbles, and the polyurethane resin sheet having 0.10 W / (m.k) or less, the polyurethane resin sheet at 45 ° C, initial load of 200 g, strain range of 0.1% to 0.5%, measurement frequency of 1.6 Hz, tensile mode The ratio of the loss elastic modulus to the storage elastic modulus is in the range of 0.130 to 0.270, and the compression modulus of the polyurethane resin sheet is 60% to 100%. The polishing pad according to claim 1, wherein the polyurethane resin sheet comprises: a first hollow body having an average particle diameter of 70 μm to 150 μm, and a second hollow body having an average particle diameter of 5 μm to 60 μm. Hollow body. The polishing pad according to claim 2, wherein the first hollow body and the second hollow body are contained in a mass ratio of 5:95 to 80:20. The polishing pad according to claim 1, wherein the polyurethane resin sheet has a bubble ratio of 20% to 60%. The polishing pad according to claim 1, wherein the polyurethane resin sheet has a density of 0.50 g/cm ³ to 0.80 g/cm ³ . The polishing pad according to claim 1, wherein the polyurethane resin sheet has a D hardness of 20 to 70 degrees. The polishing pad according to claim 1, wherein the polyol component constituting the urethane resin of the polyurethane resin sheet contains polytetrazol having a number average molecular weight of 500 to 950. Methyl diol. A method for producing a polishing pad, which is used for manufacturing a polishing pad according to any one of claims 1 to 7, wherein the manufacturing method comprises the steps of: at least a polyamine as a prepolymer The isocyanate-bonded isocyanate compound (A), the curing agent (D), the first hollow body having an average particle diameter of 80 μm to 150 μm, and the second hollow body having an average particle diameter of 5 μm to 60 μm are mixed to obtain a molded body. The polyurethane resin molded article is molded from the mixed solution for molding the molded body to obtain a polyurethane resin sheet. The method for producing a polishing pad according to claim 8, wherein the first hollow body and the second hollow body are included in a mass ratio of 5:95 to 80:20. The method for producing a polishing pad according to claim 8, wherein the hardener (D) comprises a group selected from the group consisting of a polyamine compound (D-1) and a polyol compound (D-2). At least one, and the active hydrogen group present in the hardener (D) in the polyurethane resin sheet relative to the polyurethane bond-containing isocyanate compound (A) as a prepolymer The equivalent ratio of the isocyanate groups present at the end, that is, the r value is 0.75 to 1.30, and the components are mixed. The method for producing a polishing pad according to claim 8, which further comprises the step of reacting the polyisocyanate compound (B) with the polyol compound (C) to obtain the polyamine-containing compound as a prepolymer. a isocyanate-bonded isocyanate compound (A), and the polyol compound (C) comprises a number average molecular weight of 500 to 950 Polytetramethylene glycol.