TW201641546A - Polishing pad and method of making the same - Google Patents

Abstract

This invention provides a polishing pad with excellent inhibition of polishing damage and excellent polishing processability and a method of making the same. The polishing pad is provided with polyurethane resin sheet. When being subject to test at a testing frequency of 10 rad/sec and tensile mode, the polyurethane resin sheet demonstrates a ratio (tan[delta] (25DEG C)) of less than 0.25 for the loss elastic modulus at 25DEG C E''(25DEG C ) relative to the storage elastic modulus E'(25DEG C), wherein the storage elastic modulus E' of the polyurethane resin sheet at 45-65DEG C is less than 200 MPa.

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, it relates to a polishing pad for chemical mechanical polishing (CMP) processing such as an optical material, a semiconductor element, a hard disk, or a glass substrate, and a method of manufacturing the same.

Since the surface of a material such as an optical material, a semiconductor element, a hard disk, or a glass substrate is required to be flat, polishing by a free abrasive grain method using a polishing pad is performed. The free abrasive grain method is a method in which a slurry (polishing liquid) containing abrasive grains is supplied to a polishing surface between the polishing pad and the workpiece to face the object to be polished.

The polishing pad for a semiconductor element is required to have an opening for holding the abrasive grains on the surface of the polishing pad, to maintain the rigidity of the flatness of the surface of the semiconductor element, and to prevent the scratch of the surface of the semiconductor element. As a polishing pad that meets such requirements, a polishing pad having a polishing layer produced using a urethane resin foam has been used.

The urethane resin foam is usually formed by hardening by reacting a prepolymer containing a polyurethane bond-containing isocyanate compound with a hardener (dry method). Then, the polishing pad is formed by cutting the foam into a sheet shape. A polishing pad having a hard abrasive layer formed by a dry method in this manner (hereinafter sometimes referred to simply as a hard (dry) polishing pad) is formed in the inside of the foam during hardening of the urethane resin. The smaller, substantially spherical bubbles form an open surface (opening) that maintains the slurry during the grinding process on the abrasive surface of the polishing pad formed by slicing.

As a polishing pad containing a urethane resin foam, for example, it is also known A polishing pad such as IC1000 (registered trademark, manufactured by NITTA HAAS Co., Ltd.). Further, a polishing pad having a ratio of tan δ30 of 30 ° C of 0.1 or less and a ratio of tan δ 30 at 30 ° C to tan δ 60 of 60 ° C (tan δ 30 / tan δ 60 ) of 1 to 2 is known (Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-142439

Excellent polishing properties such as high polishing treatment properties and suppression of polishing damage are required for the polishing pad.

However, the polishing pad of IC1000 (registered trademark, manufactured by NITTA HAAS Co., Ltd.) has a problem that it is easy to cause abrasion damage (scratch).

Further, since the polishing pad of Patent Document 1 has a low value of tan δ30, the polishing processability (the polishing surface of the polishing pad is about 25° C. due to frictional heat during the polishing process) is excellent. However, since tan δ 60 is smaller than tan δ 30, Therefore, if heat is generated during the polishing process (the polishing surface of the polishing pad becomes about 45 ° C to 65 ° C during the polishing process), it becomes difficult to soften. Therefore, there is a problem in that if foreign matter (grinding debris or aggregates of abrasive grains) is locally generated during polishing, the object to be polished is liable to cause polishing damage.

Therefore, the prior polishing pad is inferior in any of the aspects of suppressing the abrasive treatment property and the grinding damage. Therefore, there is a high demand for a polishing pad which is excellent in any aspect of suppressing the polishing treatment property and the polishing damage.

The inventors of the present invention have achieved the above problems, and have an object of providing polishing treatment property and polishing damage resistance during polishing by using a temperature at the time of polishing and a temperature at the time of heat generation due to friction during polishing. A polishing pad and a method of manufacturing the same.

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

[1] A polishing pad comprising a polyurethane resin sheet and 25 ° C of the polyurethane resin sheet when measured at a measurement frequency of 10 rad/sec and a tensile mode. The ratio of the loss elastic modulus E" (25 ° C) to the storage elastic modulus E' (25 ° C) (tan δ (25 ° C)) is 0.25 or less, and the above-mentioned polyurethane resin sheet is 45 to 65 The storage elastic modulus E' at ° C is 200 MPa or less.

[2] The polishing pad according to [1], wherein the polyurethane modulus resin has a loss elastic modulus E" at 25 ° C when measured at a measurement frequency of 10 rad/sec and a tensile mode. 25 ° C) ratio with respect to storage elastic modulus E' (25 ° C) (tan δ (25 ° C)) and loss elastic modulus E" (65 ° C) at 65 ° C with respect to storage elastic modulus E ' (65 ° C The ratio of the ratio (tan δ (65 ° C)), that is, tan δ (25 ° C) / tan δ (65 ° C) is 0.95 or less.

[3] The polishing pad according to [1] or [2], wherein the elastic modulus of the polyurethane resin sheet at 65 ° C is measured at a measurement frequency of 10 rad/sec and a tensile mode. The ratio of the number E" (65 ° C) to the storage elastic modulus E' (65 ° C) (tan δ (65 ° C)) is in the range of 0.12 to 0.30.

[4] The polishing pad according to any one of [1] to [3], which comprises at least one hollow body.

[5] The polishing pad according to [4], wherein the hollow body comprises a first hollow body having an average particle diameter of 5 to 60 μm and a second hollow body having an average particle diameter of 70 to 150 μm.

[6] The method for producing a polishing pad according to any one of [1] to [5] comprising the step of at least a polyurethane-containing isocyanate compound (A) as a prepolymer The mixture of the curing agent (D) and the hollow body (E) to obtain a mixed body for molding a molded article; and the molded article for forming a polyurethane resin by the mixed solution for forming the molded article Obtaining a sheet of a polyurethane resin; and the above curing agent (D) comprises at least one selected from the group consisting of a polyamine compound (D-1) and a polyol compound (D-2), and The active hydrogen group present in the hardener (D) of the polyurethane resin sheet relative to the isocyanate group present at the end of the polyurethane bond-containing isocyanate compound (A) as a prepolymer The components are mixed in such a manner that the equivalent ratio, that is, the R value is 0.60 to 1.40.

[7] The method for producing a polishing pad according to [6], wherein the hollow body (E) comprises a first hollow body having an average particle diameter of 5 to 60 μm and a second hollow body having an average particle diameter of 70 to 150 μm.

[8] The method for producing a polishing pad according to [6] or [7], which further comprises reacting the polyisocyanate compound (B) with the polyol compound (C) to obtain the above-mentioned polyamine group as a prepolymer. A step of a formate bond-containing isocyanate compound (A), and the above polyol compound (C) comprises a poly(oxytetramethylene) glycol having a number average molecular weight of 600 to 1300.

According to the present invention, it is possible to obtain a polishing pad excellent in polishing treatment property and suppression of occurrence of polishing damage.

Hereinafter, the present embodiment will be described.

<<Grinding pad>>

The polishing pad of the present invention is characterized in that it is provided with a polyurethane resin sheet, and is measured at a measurement frequency of 10 rad/sec and in a tensile mode, and the above-mentioned polyurethane resin sheet is 25 The ratio of the loss elastic modulus E" (25 ° C) to the storage elastic modulus E' (25 ° C) at a temperature of ° C (tan δ (25 ° C)) is 0.25 or less, and the above-mentioned polyurethane resin is thin. The storage elastic modulus E' at 45 to 65 ° C of the sheet is 200 MPa or less.

The above-mentioned polyurethane resin sheet means a sheet-like resin having at least two or more urethane bonds in the molecule. The urethane resin sheet preferably has at least two or more urethane bonds and at least two or more urethane 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 described later.

Further, the polyurethane resin sheet preferably has minute bubbles which are substantially spherical. The term "substantially spherical" means the concept of ordinary bubble shapes (having isotropy, spherical, elliptical, or similar shapes) existing in a molded body formed by a dry method, and utilizing The shape of the bubble contained in the formed body formed by the wet method (having anisotropy and having a structure in which the diameter from the polishing surface of the polishing pad becomes larger toward the bottom) is clearly distinguished.

(Storage elastic modulus E' and tan δ)

In the scope of the present specification and the patent application, the storage elastic modulus E' can be stored and repliable between load cycles when a sinusoidal stress is applied to the polyurethane resin sheet. The scale of energy. Further, the loss elastic modulus E" is a measure of the energy lost (consumed) between load cycles.

In the present specification and the scope of the patent application, the ratio of tan δ, the loss elastic modulus E" to the storage elastic modulus E', is an index indicating the degree of viscosity under a certain temperature condition.

The storage elastic modulus E' and the loss elastic modulus E" are respectively based on JIS K7244 and at a specific temperature (°C), a measurement frequency of 10 rad/sec, a storage elastic modulus E' in a tensile mode, and a loss elastic modulus. E".

In the present specification and the scope of the patent application, the storage elastic modulus E', the loss elastic modulus E", and tan δ in the case where the specific temperature is 25 ° C are sometimes described as the storage elastic modulus E' (25 ° C). Loss modulus E" (25 ° C) and tan δ (25 ° C). Also, in particular The same applies to the case where the temperature is 45 ° C and 65 ° C, and it is sometimes described as storage elastic modulus E' (45 ° C), loss elastic modulus E" (45 ° C) and tan δ (45 ° C), and storage elastic modulus E. '(65 ° C), loss elastic modulus E" (65 ° C) and tan δ (65 ° C).

The loss elastic modulus E" (25 ° C) at 25 ° C of the polyurethane sheet of the present invention measured at a measurement frequency of 10 rad/sec in a tensile mode with respect to the storage elastic modulus The ratio of the number E' (25 ° C) (tan δ (25 ° C)) is 0.25 or less. The tan δ (25 ° C) is preferably 0.01 to 0.25, more preferably 0.05 to 0.23, still more preferably 0.08 to 0.22. When 25 ° C) is in the above range, the polishing treatment property of the polishing pad can be improved.

Further, the polishing pad of the present invention is preferably a ratio of the loss elastic modulus E" (65 ° C) to the storage elastic modulus E' (65 ° C) at 65 ° C of the polyurethane resin sheet (tan δ ( 65 ° C)) is in the range of 0.12 to 0.30, and tan δ (65 ° C) is more preferably in the range of 0.12 to 0.25.

The storage modulus E' of the polyurethane resin sheet of the polishing pad of the present invention at 45 to 65 ° C is 200 MPa or less. The storage elastic modulus E' at 45 to 65 ° C is preferably from 1 to 200 MPa, more preferably from 10 to 180 MPa, and still more preferably from 30 to 165 MPa.

The storage elastic modulus E' (45 ° C) is 200 MPa or less, preferably 1 to 200 MPa, more preferably 10 to 180 MPa, further preferably 30 to 165 MPa, more preferably 50 to 165 MPa, and even more preferably 70 to 70. 165 MPa.

The storage elastic modulus E' (65 ° C) at 65 ° C is 200 MPa or less, preferably 1 to 200 MPa, more preferably 10 to 180 MPa, still more preferably 30 to 165 MPa, and still more preferably 30 to 130 MPa, and further more Good for 30~100MPa.

When the storage elastic modulus E' at 45 ° C to 65 ° C is within the above range, the occurrence of polishing damage (scratches) can be sufficiently suppressed.

The polishing pad of the present invention preferably has a ratio of loss elastic modulus E" (25 ° C) to storage elastic modulus E' (25 ° C) at 25 ° C of the polyurethane resin sheet (tan δ (25 ° C) )) the ratio of the loss elastic modulus E" (65 ° C) at 65 ° C to the storage elastic modulus E' (65 ° C) ratio (tan δ (65 ° C)), that is, tan δ (25 ° C) / tan δ (65 °C) is 0.95 or less. Tanδ(25 °C)/tan δ (65 ° C) is preferably from 0.50 to 0.95, more preferably from 0.65 to 0.95.

When tan δ (25 ° C) / tan δ (65 ° C) is in the above range, the polishing treatment property of the polishing pad and the occurrence of polishing damage (scratches) can be improved.

(hollow body)

In the context 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, it is preferable that the above-mentioned polyurethane resin sheet has a hollow body. The hollow body preferably has an average particle diameter of 5 to 150 μm, more preferably 10 to 140 μm, still more preferably 15 to 130 μm.

One type of hollow body may be used for the hollow body, or two or more types of hollow bodies may be used in combination. Further, when two or more kinds of hollow bodies are used in combination, it is preferable to include a first hollow body having an average particle diameter of 5 to 70 μm and a second hollow body having an average particle diameter of 70 to 150 μm. The average particle diameter of the first hollow body is more preferably from 10 to 55 μm, still more preferably from 15 to 50 μm. The average particle diameter of the second hollow body is more preferably from 80 to 140 μm, still more preferably from 90 to 130 μm.

Since the hollow body is included, 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, the polishing damage is less likely to occur.

(thickness)

The thickness of the urethane resin sheet of the polishing pad of the present invention is not particularly limited, and can be, for example, 0.5 to 3.0 mm, preferably 0.5 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 means a polyamine group which is added as a part of a chain constituting the polyurethane resin by a subsequent polymerization reaction. The raw material component of the acid ester resin.

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

The urethane resin sheet of the polishing pad of the present invention preferably comprises poly(oxytetramethylene) diol (PTMG) having a number average molecular weight of 600 to 1300 as a polyol constituting the polyurethane resin. ingredient. The poly(oxytetramethylene) glycol preferably has a number average molecular weight of from 700 to 1,100, and more preferably from 800 to 1,050.

The polishing pad of the present invention can be preferably used for polishing of enamel, hard disk, glass substrate, mother glass for thin liquid crystal display, semiconductor wafer, semiconductor element, etc., especially chemical mechanical polishing (CMP) of semiconductor elements.

<<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 in that it comprises the steps of mixing at least a polyurethane-containing isocyanate compound (A), a hardener (D), and a hollow body (E) as a prepolymer. And obtaining a mixture for forming a molded body (mixing step); and molding the polyurethane resin molded article by the mixed liquid for forming the molded body to obtain a polyurethane resin sheet (molded body forming step); The hardener (D) contains at least one selected from the group consisting of a polyamine compound (D-1) and a polyol compound (D-2), and is hardened by the above-mentioned polyurethane resin sheet. The equivalent ratio of the active hydrogen group present in the agent (D) to the isocyanate group at the terminal of the polyurethane bond-containing isocyanate compound (A) as the prepolymer, that is, the R value is 0.60 to 1.40. The ingredients were mixed.

Hereinafter, each step will be described.

<mixing step>

In the mixing step, at least a polyurethane bond-containing isocyanate compound (A), a curing agent (D), and a hollow body (E) are mixed as a raw material of the polyurethane resin sheet. Further, it is also possible to combine the components other than the above without departing from the effects of the present invention.

Hereinafter, each component will be described.

[(A) Isocyanate compound containing a polyurethane linkage]

The isocyanate compound (A) containing a polyurethane linkage as a prepolymer is a compound obtained by reacting the following polyisocyanate compound (B) with a polyol compound (C) under usual use conditions, And it is a molecule containing a polyurethane bond and an isocyanate group in a molecule. Further, other components may be contained in the isocyanate compound containing a polyurethane bond within the range in which the effects of the present invention are not impaired.

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

[(B) Polyisocyanate Compound]

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

The polyisocyanate compound (B) is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, examples of the diisocyanate compound having two isocyanate groups in the molecule include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), and 2,4-toluene diisocyanate. (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI , 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, benzenedimethyl-1, 4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene Base-1,2-diisocyanate, butyl-1,2-diisocyanate, cyclohexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, p-phenylene isothiocyanate Benzyl-1,4-diisothiocyanate, hypoethyl diisothiocyanate, and the like.

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

These polyisocyanate compounds (B) may be used singly or in combination of a plurality of polyisocyanate compounds.

[(C) Polyol Compound]

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

Examples of the polyol compound (C) for synthesizing a polyurethane bond-containing isocyanate compound as a prepolymer include diol compounds such as ethylene glycol, diethylene glycol (DEG), and butylene glycol. a triol compound or the like; a polyether polyol compound such as poly(oxytetramethylene) glycol (or polytetramethylene ether 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 to which ethylene oxide is added may also be used. Among these, PTMG, or a combination of PTMG and DEG is preferred. The number average molecular weight (Mn) of the PTMG is preferably from 600 to 1300, more preferably from 700 to 1,100, and still more preferably from 800 to 1,050. The number average molecular weight can be determined by gel permeation chromatography (GPC). Further, when the number average molecular weight of the polyol compound is measured by a polyurethane resin, each component may be decomposed by a conventional method such as amine decomposition and then estimated by GPC.

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

(NCO equivalent of prepolymer)

Further, "(the mass of the polyisocyanate compound (B) + the polyol compound (C) is utilized" (parts by mass) / [(polyisocyanate compound (B) 1 molecule functional group × mass fraction of polyisocyanate compound (B) / molecular weight of polyisocyanate compound (B)) - (polyol compound (C) 1 molecule functional group × parts by mass of the polyol compound (C) / molecular weight of the polyol compound (C)) The NCO equivalent of the prepolymer obtained by the formula "] represents the molecular weight of the PP (prepolymer) of one NCO group. The NCO equivalent is preferably from 200 to 800, more preferably from 300 to 700, and even more preferably from 400 to 600.

[(D) hardener]

The production method of the present invention is a step of mixing a curing agent (also referred to as a chain extender) with an isocyanate compound containing a polyurethane bond in a mixing step. By adding a hardener, in the subsequent molding step of the shaped body, the main chain end of the polyisocyanate-containing isocyanate compound as a prepolymer is bonded to a hardener to form a polymer chain, and is hardened. .

As the hardener, for example, a polyamine compound (D-1) and/or a polyol compound (D-2) can be used.

((D-1) polyamine compound)

In the present specification and the scope of the patent application, the term "polyamine compound" means a compound having two or more amine groups in the molecule.

As the polyamine compound (D-1), an aliphatic or aromatic polyamine compound, particularly a diamine compound, may be used, and examples thereof include ethylenediamine, propylenediamine, hexamethylenediamine, and isophor. Ketodiamine, dicyclohexylmethane-4,4'-diamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as 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.

As the polyamine compound, a diamine compound is preferred, and more preferably MOCA, diamine II Phenylmethane, diaminodiphenylphosphonium, and more preferably MOCA.

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

As the polyamine compound (D-1), in order to make it easy to mix with other components and/or to improve the uniformity of the bubble diameter in the subsequent formed body forming step, it is preferred to reduce it as needed in the heated state. Depressurize by pressing. The defoaming method under reduced pressure may be a method known in the production of polyurethane, and for example, defoaming may be performed using a vacuum pump at a 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.

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

Further, in the present invention, in addition to the polyol compound (C) for forming an isocyanate group-containing compound as the prepolymer, a polyol compound (D-2) may be additionally used as a curing agent.

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 diol such as pentanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, poly(oxytetramethylene) glycol, polyethylene glycol, A high molecular weight polyol compound such as polypropylene glycol or the like.

The above 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 a mixture of these 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, the active hydrogen group (amine group and hydroxyl group) present in the curing agent (D) is relative to the isocyanate compound (A) present in the polyurethane-containing bond as a prepolymer. The component is mixed so that the equivalent ratio of the isocyanate groups at the end thereof is, that is, the R value is 0.60 to 1.40. The R value is preferably from 0.65 to 0.1.30, more preferably from 0.70 to 1.20.

[(E) hollow body]

In the method for producing a polishing pad of the present invention, the hollow body (E) is used to contain bubbles in the interior of the polyurethane resin molded body.

The term "hollow body" means a microsphere having a void. The microspheres include a spherical shape, an elliptical shape, and a shape similar to the above. Examples of the hollow body include heating and expansion of an unfoamed heat-expandable microsphere composed of a shell (polymer shell) containing a thermoplastic resin and a low-boiling hydrocarbon contained in the shell.

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- 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, it is preferred to use a hollow body (E) having an average particle diameter of 5 to 150 μm, more preferably a hollow body (E) of 10 to 140 μm, and more preferably 15 to 130 μm. Hollow body (E).

Further, in the case of using two types of hollow bodies, the first hollow body preferably has an average particle diameter of 5 to 60 μm, more preferably 10 to 55 μm, still more preferably 15 to 50 μm. The second hollow body preferably has an average particle diameter of 70 to 150 μm, more preferably 80 to 140 μm, still more preferably 90 to 130 μm.

Examples of the first hollow body include EXPANCEL 461DE20d70 (manufactured by EXPANCEL) (the outer structure of a vinylidene chloride-acrylonitrile-based outer casing and an average particle diameter of 15 to 25 μm and a density of 70 ± 6 kg/m ³ . Hollow spherical body), EXPANCEL551DE20d42 (manufactured by EXPANCEL) (expanded micro hollow spheroids composed of a vinylidene chloride-acrylonitrile-based outer shell and having an average particle diameter of 30 to 50 μm and a density of 42 ± 4 kg/m ³ ).

Examples of the second hollow body include Matsumoto Microsphere F-80DE (manufactured by Matsumoto Oil & Fats Co., Ltd.) (acrylonitrile-based outer shell composition and an average particle diameter of 90 to 130 μm and a density of 25 ± 5 kg/m ³ . Tiny hollow spheroids).

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

The hollow body (E) preferably contains the prepolymer in an amount of 10 to 40 parts by mass, more preferably 15 to 30 parts by mass per 1000 parts by mass.

Further, when the hollow body (E) has the first hollow body and the second hollow body, the mass of the first hollow body and the second hollow body is preferably 10:90 to 90:10, more preferably 30:70. ~90:10, and more preferably 40:60~90:10, and even more preferably 50:50~80:20.

Further, in addition to the above components, the previously used foaming agent may be used in combination with the above-mentioned micro hollow spheres insofar as the effects of the present invention are not impaired, and a non-reactive gas may be blown into the above components in the following mixing step. . The foaming agent may, for example, be a foaming agent containing water or a hydrocarbon having 5 or 6 carbon atoms as a main component. Examples of the hydrocarbon include a chain hydrocarbon such as n-pentane or n-hexane, or an alicyclic hydrocarbon such as cyclopentane or cyclohexane.

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

In the mixing step, at least a polyurethane-containing isocyanate compound (A), a curing agent (D), and a hollow body (E) as a prepolymer are supplied to a mixer, stirred, and mixed. The mixing order is not particularly limited, and a mixture of an isocyanate compound (A) containing a polyurethane bond and a hollow body (E), and a hardener (D) and a view are preferably used. a mixture of other ingredients that are required to be mixed, and the two mixtures are supplied Mix and stir into the mixer. Thus, a mixed liquid for molding a shaped body can be prepared. The mixing step is carried out while heating to a temperature at which the fluidity of each of the above components can be ensured.

For example, a prepolymer (isocyanate containing a polyurethane bond) solution containing the above hollow body (E) heated to 40 to 80 ° C, and a hardener (D) heated to 80 to 130 ° C can be used. Put in a mixer and stir. The stirring time is appropriately adjusted according to the number of teeth, the number of revolutions, the gap, and the like of the mixer, for example, 0.5 to 4 seconds.

<Forming body forming step>

In the molding process, the polyurethane molding resin is formed by flowing the mixed liquid for molding a molded body prepared in the mixing step into a mold frame of 50 to 100 ° C to be cured. At this time, the prepolymer is reacted with a curing agent to form a polyurethane resin, and the mixture is cured in a state where the hollow body is substantially uniformly dispersed in the resin. 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 thereafter cut into a sheet shape to form a polyurethane resin sheet. By performing slicing, it is possible to provide openings in the surface of the sheet. In this case, in order to form an opening of the polishing surface which is excellent in abrasion resistance and is not easily clogged, it can be aged at 80 to 120 ° C for about 1 hour to 10 hours.

The polyurethane resin sheet obtained in this manner is then attached to a surface opposite to the polishing surface by a double-sided tape and cut into a specific shape, preferably in the form of a disk, to form a polishing of the present invention. pad. The double-sided tape is not particularly limited and can be arbitrarily selected from among double-sided tapes well known in the art.

Further, the polishing pad of the present invention may be a single layer structure including only a polyurethane resin sheet, or may be attached to the opposite side of the polishing surface of the polyurethane resin sheet (abrasive layer). A plurality of layers formed by combining other layers (lower layer, support layer). The characteristics of the other layers are not particularly limited, and it is preferred to apply a softer to the polyurethane resin sheet on the opposite side to the polished surface of the urethane resin sheet (A hardness or D hardness). Small) layer. By setting soft In the layer of the polyurethane resin sheet, the polishing flatness is further improved.

In the case of having a plurality of layers, the plurality of layers are pressed and adhered to each other using a double-sided tape or an adhesive as needed. The double-sided tape or the adhesive used in this case is not particularly limited, and can be optionally used from among double-sided tapes or adhesives known in the art.

Further, the polishing pad of the present invention may be subjected to grinding treatment on the polished surface of the polyurethane resin sheet and/or the surface opposite to the polishing surface, or by performing groove processing or embossing or hole on the polished surface. For processing (punching), the substrate and/or the adhesive layer may be bonded to the urethane resin sheet, and a light transmitting portion may be provided.

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 is mentioned.

The shape of the groove processing and the embossing processing 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 platen of the grinder so that the polishing surface of the urethane resin sheet faces the object to be polished. Then, while the abrasive slurry is supplied, the polishing platen is rotated to polish the processed surface of the object to be polished.

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

As described above, the polishing pad of the present invention is excellent in both the polishing treatability and the suppression of the occurrence of polishing damage. The reason is not clear, and it is estimated as follows. That is, at the temperature (about 25 ° C) at the time of the polishing treatment, the polishing pad is hard and sufficiently polished, and on the other hand, the polishing pad is softened at a temperature (about 45 ° C to 65 ° C) during the polishing process. Even if foreign matter (grinding debris or aggregates of abrasive grains) is locally generated, it is not easy to damage the object to be polished. because Therefore, it is considered that the polishing pad of the present invention is excellent in both the polishing treatment property and the suppression of the occurrence of polishing damage.

[Examples]

Hereinafter, the present invention will be described in further detail by way of examples, but the invention is not limited by the examples.

In each of the examples, comparative examples, and Tables 1 and 2, "parts" means "parts by mass" unless otherwise specified.

Further, the respective symbols in Tables 1 to 2 mean the following.

The NCO equivalent means "(the mass of the polyisocyanate compound (B) + the mass (part) of the polyol compound (C)) / [(the number of functional groups of the polyisocyanate compound (B) 1 molecule × polyisocyanate The mass (parts) of the compound (B) / the molecular weight of the polyisocyanate compound (B)) - (the number of functional groups of the polyol compound (C) 1 molecule × the mass (parts) of the polyol compound (C) / the polyol compound (C) The molecular weight of the prepolymer (PP) of one NCO group obtained by molecular weight)]".

The R value is, as described above, the value of the equivalent ratio of the active hydrogen group (amine group and hydroxyl group) present in the hardener to the terminal isocyanate group in the prepolymer.

[Example 1]

770 parts of 2,4-toluene diisocyanate was reacted with 1000 parts of poly(oxytetramethylene) glycol (PTMG) having a molecular weight of 850 and 155 parts of diethylene glycol to obtain an isocyanate-terminated urethane. Ester prepolymer. Adding to the 1000 parts of the obtained isocyanate-terminated urethane prepolymer, the shell portion contains an acrylonitrile-vinylidene chloride copolymer and the particles containing the isobutane gas in the shell have a size of 15 to 25 μm. 12 parts of the expanded hollow hollow spheroid (trade name: EXPANCEL 461 DE20d70 (manufactured by EXPANCEL)), and the shell portion containing acrylonitrile-based particles containing pentane gas in the shell is expanded to a size of 90 to 130 μm. 12 parts of a small hollow spheroid (trade name: Matsumoto Microsphere F-80DE (manufactured by Matsumoto Oil & Fats Co., Ltd.)) was mixed and mixed to obtain a mixed liquid. The mix that will be obtained The liquid mixture was added to the first liquid tank, and the temperature was kept at 80 °C. Then, in addition to the first liquid, 3,3'-dichloro-4,4'-diaminodiphenylmethane (trade name: PANDEX E (manufactured by DIC)) as a curing agent was separately prepared, and in the second The temperature was maintained at 120 ° C in the tank. The liquid of each of the first liquid tank and the second liquid tank is injected from each injection port to a mixer having two injection ports so that the R ratio of the equivalent ratio of the isocyanate of the prepolymer to the amine of the curing agent is 0.70. . The two kinds of liquids to be injected were mixed and stirred, and the mold was injected into a molding machine preheated to 100 ° C. Thereafter, the mold was clamped and heated at 110 ° C for 30 minutes to be hardened once. The molded product which had been hardened once was demolded, and thereafter, secondary hardening was carried out at 130 ° C for 2 hours in an oven to obtain a urethane molded product. The obtained urethane formed product was allowed to cool to 25 ° C, and thereafter, it was further heated in an oven at 120 ° C for 5 hours and then cut into a thickness of 1.3 mm to obtain a polishing pad.

[Examples 2 to 5]

The polishing pad was obtained by the same method as in Example 1 except that the R value was changed as shown in Table 1.

[Embodiment 6]

770 parts of 2,4-toluene diisocyanate was reacted with a mixed diol of 1242 parts of poly(oxytetramethylene) glycol (PTMG) having a molecular weight of 1000 and 69 parts of diethylene glycol to obtain an isocyanate-terminated urethane. Ester prepolymer. Adding to the 1000 parts of the obtained isocyanate-terminated urethane prepolymer, the shell portion containing the acrylonitrile-vinylidene chloride copolymer and the particles containing the isobutane gas in the shell have a size of 30 to 50 μm. Expanded tiny hollow spheroid (commodity Name: EXPANCEL 551 DE20d42 (manufactured by EXPANCEL)) The expanded hollow spherical spheroids of 18 parts and shells containing acrylonitrile-based particles containing pentane gas in the shell and having a size of 90 to 130 μm (trade name: A portion of 4.5 parts of Matsumoto Microsphere F-80DE (manufactured by Matsumoto Oil & Pharmaceutical Co., Ltd.) was mixed to obtain a mixed liquid. The obtained mixed liquid was added to the first liquid tank, and the temperature was kept at 80 °C. Then, in addition to the first liquid, 3,3'-dichloro-4,4'-diaminodiphenylmethane (manufactured by DIC Corporation; trade name: PANDEX E) and 3,3' as a curing agent were separately prepared. - a mixed hardener of dichloro-4,4'-diaminodiphenylmethane and a polyether polyol (manufactured by DIC Corporation; trade name: PANDEX E50) is mixed at a ratio of 1:1 and added The temperature was maintained at 120 ° C in the second liquid bath. The liquid of each of the first liquid tank and the second liquid tank was injected from each injection port to a mixer having two injection ports at a R value of 0.85. The two kinds of liquids to be injected were mixed and stirred, and the mold was injected into a molding machine preheated to 80 ° C. Thereafter, the mold was clamped and heated at a mold temperature of 80 ° C for 30 minutes to be hardened once. The molded product which had been hardened once was demolded, and thereafter, secondary hardening was carried out at 120 ° C for 5 hours in an oven to obtain a urethane molded product. The obtained urethane formed product was cut into a thickness of 1.3 mm to obtain a polishing pad.

[Examples 7 to 9]

The polishing pad was obtained by the same method as in Example 6 except that the R value was changed as shown in Table 2.

[Comparative Example 1]

In Comparative Example 1, an IC1000 polishing pad manufactured by NITTA HAAS Co., Ltd. was used.

[Comparative Example 2]

1000 parts of "DC-6912" (TDI-based prepolymer, NCO equivalent 540) manufactured by Japan Polyurethane Co., Ltd., which is a prepolymer, was added to the first liquid tank, and the temperature was kept at 80 °C. Then, 274 parts of "PANDEX E50" manufactured by DIC Corporation, which is a curing agent, was added to the second liquid tank in addition to the first liquid, and the temperature was kept at 120 °C. Further, 42 parts of "HYPROX TG-3000" (polypropylene glycol having a molecular weight of 3,000) and 12 parts of water as a foaming agent manufactured by DIC Corporation, which is a curing agent, were mixed in the third liquid tank, and the mixture was kept at 50 °C. The liquid of each of the first liquid tank, the second liquid tank, and the third liquid tank is injected from each injection port into a mixer having three injection ports at a ratio of the above-mentioned parts. The three kinds of liquids to be injected were mixed and stirred, and the mold was injected into a molding machine preheated to 100 ° C. Thereafter, the mold was clamped and heated at a mold temperature of 100 ° C for 30 minutes to be hardened once. The molded product which had been hardened once was demolded, and thereafter, secondary hardening was carried out at 130 ° C for 5 hours in an oven to obtain a urethane molded product. The obtained urethane formed product was cut into a thickness of 1.3 mm to obtain a polishing pad.

<physical property>

For each of the above examples and comparative examples, the RSAIII manufactured by TA Instruments has an initial load of 10 to 700 g, a strain range of 0.1 to 1.0%, a measurement frequency of 10 rad/sec, and a temperature increase rate of 3 ° C/min for heating from 20 ° C. The storage elastic modulus E', the loss elastic modulus E", and the tan δ of the test piece of 5 mm × 10 mm at 25 ° C, 45 ° C and 65 ° C at 100 ° C were measured. The detailed conditions are as follows.

Measuring device: TA Instruments Japan RSAIII

Test direction: stretching

Test piece: 5 × 10mm

Load: 200g

Strain: 0.1%

Frequency: 10 radians/second (=1.59 Hz)

Temperature: 20~100°C

Sample thickness: 1.3mm

The results are shown in Table 3.

<<Evaluation test>>

<1. Grinding treatment test>

For each of the examples and the comparative examples, the polishing treatment was carried out under the following conditions and evaluated.

(grinding conditions)

‧Use grinding machine: manufactured by Ebara Seisakusho Co., Ltd., F-REX300

‧ number of revolutions: (platen) 80rpm, (dresser) 36rpm

‧ Pressure: 30N

‧ abrasive: water

‧Abrasant temperature: 20 ° C

‧ Abrasives discharge: 500ml/min

‧ Grinding time: 30 minutes

‧ Dresser: Sumitomo 3M A188 diamond grinding (outer diameter 4.25inch)

‧ atomizer: not used

(Evaluation of abrasiveness)

The polished surface before and after the polishing treatment was imaged by a laser CCD (Charge Coupled Device). The laser CCD image was VK-X200 manufactured by KEYENCE Corporation (magnification: objective lens × 10 eyepiece × 20; measurement pitch: 6 μm; brightness: 6207). Thereafter, the captured image was binarized, and the amount of increase in the polished surface was measured. The binarization treatment used the analysis software WinRoof ver 6.5 (measurement range: 1 mm x 1.4 mm; median: filter 5*5; contrast: 75; automatic binarization: discriminant analysis threshold 88).

The amount of increase in the polishing surface after the polishing treatment is determined to be inferior (×) in the polishing pad of 10% or less compared with the polished surface before the polishing treatment, and the polishing property of the polishing pad exceeding 10% to less than 30% is insufficient ( △), the polishing pad of 30% or more of the polishing pad is good (○). The results are shown in Table 3.

<2. Grinding test (with or without scratches)>

The polishing pads of the respective examples and comparative examples were subjected to polishing treatment under the following polishing conditions, and evaluation of polishing damage (scratches) was performed. As the object to be polished, a TEOS (Tetra Ethyl Ortho Silicate) film was used.

The 25 substrates were polished, and the five substrates of the 21st to 25th substrates after the polishing were measured in a high-sensitivity measurement mode of a wafer surface inspection device (Surfscan SP1DLS, manufactured by KLA-Tencor Co., Ltd.). The presence or absence of the scratch on the surface was evaluated such that the scratch was not observed and the scratch was observed to be ×. The results are shown in Table 3.

Further, the polishing conditions used in the above test were as follows.

‧Use grinding machine: 荏原制作,F-REX300

‧ polishing pad diameter: 740

‧ number of revolutions: (platen) 70rpm, (top ring) 71rpm

‧ Grinding pressure: 3.5psi

‧ Abrasives: SS25 manufactured by Cabot (using SS25 stock solution: pure water = 1:1 mixture)

‧Abrasant temperature: 20 ° C

‧Blasting amount of abrasive: 200ml/min

‧Use workpiece (abrasive): TEOS film at 12 inches A substrate formed by using PECVD (Plasma Enhanced Chemical Vapor Deposition) on a silicon wafer to form an epoxy film having a thickness of 1 μm.

‧ Grinding time: 60sec

<test result>

As a result of the polishing treatment test, the values of tan δ (25 ° C) of the polishing pads of Examples 1 to 9 were 0.25 or less, and the amount of increase of the polished surface after the polishing treatment was as high as 30% or more. On the other hand, the polishing pad of Comparative Example 2 had a high value of tan δ (25 ° C) and was inferior in abrasiveness.

Further, as a result of the polishing test, the values of E' (45 ° C) and E' (65 ° C) of the polishing pads of Examples 1 to 9 were 200 MPa or less, and no scratches were observed. On the other hand, the values of E' (45 ° C) and E' (65 ° C) of the polishing pad of Comparative Example 1 were high, and the occurrence of scratches was confirmed.

Therefore, since the polishing pad of the present invention has a range of tan δ (25° C.), E′ (45° C.), and E′ (65° C.), it is determined that the polishing property and the occurrence of scratches are excellent.

[Industrial availability]

The polishing pad of the present invention is excellent in both the polishing treatment property and the suppression of the occurrence of polishing damage. Therefore, the polishing pad of the present invention and the method for producing the same are industrially available.

Claims (8)

A polishing pad which is provided with a polyurethane resin sheet and has a loss elasticity at 25 ° C of the above-mentioned polyurethane film sheet when measured at a measurement frequency of 10 rad/sec and a tensile mode. The ratio of the modulus E" (25 ° C) to the storage elastic modulus E' (25 ° C) (tan δ (25 ° C)) is 0.25 or less, and the storage of the above-mentioned polyurethane resin sheet at 45 to 65 ° C The elastic modulus E' is 200 MPa or less. When the polishing pad of claim 1 is measured at a measurement frequency of 10 rad/sec and a tensile mode, the loss elastic modulus E" (25 ° C) of the polyurethane resin sheet at 25 ° C is relatively The ratio of the storage elastic modulus E' (25 ° C) (tan δ (25 ° C)) to the loss elastic modulus E" (65 ° C) at 65 ° C relative to the storage elastic modulus E' (65 ° C) ( The tan δ (65 ° C) ratio, that is, tan δ (25 ° C) / tan δ (65 ° C) is 0.95 or less. When the polishing pad of claim 1 is measured at a measurement frequency of 10 rad/sec and a tensile mode, the loss elastic modulus E" (65 ° C) of the polyurethane resin sheet at 65 ° C is relatively The ratio of the storage elastic modulus E' (65 ° C) (tan δ (65 ° C)) is in the range of 0.12 to 0.30. The polishing pad of claim 1, which comprises at least one hollow body. The polishing pad according to claim 4, wherein the hollow body comprises a first hollow body having an average particle diameter of 5 to 60 μm and a second hollow body having an average particle diameter of 70 to 150 μm. A method for producing a polishing pad according to claim 1, comprising the steps of: at least a polyurethane-containing isocyanate compound (A), a hardener (D), and a hollow body (E) as a prepolymer Mixing to obtain a mixed solution for forming a shaped body; and The polyurethane resin molded article is formed by the above-mentioned mixed solution for molding a molded body to obtain a polyurethane resin sheet; and the curing agent (D) contains a polyamine compound (D-1) and a polyol selected from the group consisting of polyamine compound (D-1) and polyol At least one of the group consisting of the compound (D-2), and the active hydrogen group present in the curing agent (D) of the above-mentioned polyurethane resin sheet relative to the content contained in the prepolymer The components are mixed so that the equivalent ratio of the isocyanate groups at the terminal of the isocyanate compound (A) of the polyurethane bond is 0.60 to 1.40. The method for producing a polishing pad according to claim 6, wherein the hollow body (E) comprises a first hollow body having an average particle diameter of 5 to 60 μm and a second hollow body having an average particle diameter of 70 to 150 μm. The method for producing a polishing pad according to claim 6, which further comprises reacting the polyisocyanate compound (B) with the polyol compound (C) to obtain the above-mentioned polyurethane bond-containing isocyanate compound as a prepolymer ( The step of A), wherein the above polyol compound (C) comprises poly(oxytetramethylene) glycol having a number average molecular weight of 600 to 1300.