KR101410116B1 - Polishing pad and method for manufacturing the polishing pad - Google Patents

Abstract

It is an object of the present invention to provide a polishing pad excellent in flatness and polishing stability without generating scratches. An aspect of the present invention is to provide a superfine fiber scaffold and a polymer elastic body formed of microfine fibers having an average fineness of 0.01 to 0.8 dtex and the polymer elastomer having a glass transition temperature of -10 占 폚 or less, Is 90 to 900 MPa, and the absorption rate when absorption saturated at 50 占 폚 is 0.2 to 5 mass%.

Description

TECHNICAL FIELD [0001] The present invention relates to a polishing pad and a polishing pad,

The present invention relates to a polishing pad, and more particularly to various devices such as various devices and various substrates on which planarization or mirror-polishing is performed, such as semiconductor substrates, semiconductor devices, compound semiconductor devices, compound semiconductor substrates, , An abrasive pad for abrading an LED product, a bare silicon wafer, a silicon wafer, a hard disk substrate, a glass substrate, a glass substrate, a metal substrate, a metal product, a plastic substrate, a plastic substrate, a ceramic substrate, .

2. Description of the Related Art In recent years, along with the integration of integrated circuits and the multilayer wiring, a semiconductor wafer on which an integrated circuit is formed is required to have a high degree of flatness.

BACKGROUND OF THE INVENTION Chemical mechanical polishing (CMP) is known as a polishing method for polishing semiconductor wafers. CMP is a method of polishing a surface of a substrate to be polished by a polishing pad while dropping a slurry of abrasive grains.

The following Patent Documents 1 to 4 disclose a polishing pad used for CMP, which is produced by foam-molding a two-liquid curing type polyurethane and is formed of a polymer foam having a closed cell structure. Such a polishing pad is preferably used for polishing a semiconductor wafer which requires high precision flatness because it has a higher rigidity than a non-woven type polishing pad which will be described later.

The polishing pad made of a polymer foam having a closed cell structure is produced by, for example, foam molding a two-liquid curing type polyurethane. Since such a polishing pad has a relatively high rigidity, a load is selectively applied to the convex portion of the substrate to be polished at the time of polishing, and as a result, the polishing rate (polishing rate) becomes relatively high. However, when the agglomerated abrasive grains are present on the abrasive surface, a load is selectively applied to the agglomerated abrasive grains, and scratches (scratches) are easily generated on the abrasive surface. Particularly, as described in Non-Patent Document 1, scratches and interface delamination are particularly likely to occur when polishing a substrate having a copper wiring easily scratched and a low dielectric constant material having poor adhesion at the interface. Further, in the mold expansion molding, it is difficult to uniformly foam the elastomeric polymer, so that the flatness of the substrate to be polished and the polishing rate at the time of polishing tend to be easily varied. Further, in the case of a polishing pad having independent holes, abrasive grains are clogged with voids derived from independent holes. As a result, when used for a long time, the polishing rate decreases as the polishing proceeds (this property is also referred to as polishing stability).

On the other hand, as different types of polishing pads, Patent Documents 5 to 14 disclose a polishing pad of a nonwoven fabric type obtained by impregnating a polyurethane resin into a nonwoven fabric and wet-solidifying the same. Non-woven type polishing pads are excellent in flexibility. Therefore, when abrasive grains aggregated on the abrasive surface of the abrasive substrate exist, the abrasive pad is deformed, thereby suppressing the load selectively applied to the abrasive grains. However, the polishing pad of the nonwoven fabric type tends to change the polishing characteristics over time, which is difficult to use for precise planarization processing. Furthermore, since the polishing pad is excessively flexible and is deformed following the surface shape of the substrate to be polished, it is difficult to obtain a high leveling performance (a property of flattening the substrate to be polished) or a size of 2 to 10 decite Local stress concentration is inevitable.

In recent years, there has been known a nonwoven fabric type polishing pad obtained by using a nonwoven fabric formed of a microfine fiber bundle for the purpose of achieving a higher leveling performance in recent years (see, for example, Patent Documents 15 to 18). Specifically, for example, Patent Document 15 discloses a nonwoven fabric consisting of a bundle of polyester microfine fibers having an average fineness of 0.0001 to 0.01 dtex and a polymeric elastomer containing polyurethane as a main component existing in the nonwoven fabric inner space A polishing pad made of a sheet-like material is disclosed. According to such a polishing pad, it is described that highly precise polishing processing can be realized.

However, in the polishing pads described in Patent Documents 15 to 18, since the nonwoven fabric obtained by needle punching the ultrafine fibers having the small fineness is used, the apparent density is low and the porosity is high. As a result, only a soft and low-rigidity polishing pad can be obtained, and the surface is deformed following the surface shape, so that a high leveling performance is not sufficiently obtained.

Further, in such a nonwoven fabric type polishing pad, the details of the polymeric elastomer are not described in any literature, and the description of the stability with time is not sufficient.

Japanese Patent Application Laid-Open No. 2000-178374 Japanese Patent Application Laid-Open No. 2000-248034 Japanese Patent Application Laid-Open No. 2001-89548 Japanese Laid-Open Patent Publication No. 11-322878 Japanese Patent Application Laid-Open No. 2002-9026 Japanese Patent Application Laid-Open No. 11-99479 Japanese Laid-Open Patent Publication No. 2005-212055 Japanese Patent Application Laid-Open No. 3-234475 Japanese Patent Application Laid-Open No. 10-128674 Japanese Patent Application Laid-Open No. 2004-311731 Japanese Patent Application Laid-Open No. 10-225864 Japanese Published Patent Application No. 2005-518286 Japanese Patent Application Laid-Open No. 2003-201676 Japanese Patent Application Laid-Open No. 2005-334997 Japanese Patent Application Laid-Open No. 2007-54910 Japanese Patent Application Laid-Open No. 2003-170347 Japanese Patent Application Laid-Open No. 2004-130395 Japanese Laid-Open Patent Publication No. 2002-172555

 Kashiwagi Masahiro et al., &Quot; Science of CMP ", Science Forum Co., Ltd., August 20, 1997, p. 113 ~ 119

An object of the present invention is to provide a polishing pad which is excellent in flatness performance and polishing efficiency without generating scratches well.

An aspect of the present invention is to provide a superfine fiber scaffold and a polymer elastic body formed of microfine fibers having an average fineness of 0.01 to 0.8 dtex and the polymeric elastomer having a glass transition temperature of -10 占 폚 or less, Is 90 to 900 MPa, and the absorption rate when absorption saturated at 50 占 폚 is 0.2 to 5 mass%.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description.

A substrate made of microfine fibers generally has a large surface area and low bending elasticity. Therefore, a polishing pad obtained by impregnating a nonwoven fabric made of microfine fibers with a polymeric elastomer in a conventional manner has a large contact area with a substrate to be polished, so that soft polishing can be carried out. However, only a low stiffness can be obtained, There was a problem in characteristics and time-dependent polishing stability. Since the pores of the nonwoven fabric are high in slurry, the abrasion rate can be easily increased because of the high liquid retentivity of the abrasive slurry. However, since the pores occupy more than half of the apparent volume, impregnation of a conventionally known nonwoven fabric with a polymeric elastomer The resulting polishing pad can be polished with good efficiency, but has low stiffness and has problems in flatness and time-dependent polishing stability.

The present inventors have found that (1) a polymeric elastomer having a specific glass transition temperature, a storage elastic modulus and a specific absorption rate is used as a microfine fiber embedding material composed of microfine fibers to obtain a polishing pad having high rigidity, 2) The fiber is easily fibrillated at the time of polishing on the surface of the polishing pad to increase the contact area with the substrate to be polished and the wettability to be high, so that the retention of the abrasive slurry is enhanced, As a result, the polishing rate is increased. (3) Since the surface of the polishing pad is softly contacted by the microfine fibers, the stress concentration during the polishing process can be prevented from being caused to occur. So that the present invention has been accomplished. Further, it has been found that the porosity of the polishing pad is 50% or more, which makes it possible to enhance the retention of the abrasive slurry and to have high rigidity, and is particularly suitable for bare silicon wafer polishing.

That is, the polishing pad according to the present embodiment comprises a microfine fiber sculpture formed of microfine fibers having an average fineness of 0.01 to 0.8 dtex and a polymeric elastomer. The polymeric elastomer has a glass transition temperature of -10 캜 or lower Deg.] C and 50 [deg.] C of 90 to 900 MPa, and an absorption rate when absorption saturated at 50 [deg.] C is 0.2 to 5 mass%.

Hereinafter, the structure, manufacturing method, and method of use of the polishing pad of the present embodiment will be described.

[Configuration of polishing pad]

The microfine fiber block is formed of microfine fibers having an average fineness of 0.01 to 0.8 dtex, preferably 0.05 to 0.5 dtex. When the average fineness of the microfine fibers is less than 0.01 dtex, the microfine fiber bundles near the surface of the polishing pad are not sufficiently divided, and as a result, the holding power of the abrasive slurry is lowered and the polishing efficiency and the polishing uniformity are lowered . On the other hand, when the average fineness of the microfine fibers exceeds 0.8 dtex, the surface of the polishing pad becomes excessively rough, the polishing rate decreases, and the stress in polishing by the fibers becomes large, and scratches tend to occur.

The microfine fiber embedding body is preferably composed of microfine fiber bundles of 5 to 70 microfine fibers, more preferably 10 to 50 microfine fiber bundles. When the number of fines of the ultrafine fibers exceeds 70, the microfine fibers near the surface of the polishing pad are not sufficiently dispersed, and as a result, the holding power of the abrasive slurry is lowered. On the other hand, when the number of the microfine fiber bundles is less than 5, the fineness is substantially increased or the fiber density of the surface tends to be lowered, and the surface of the polishing pad becomes too rough and the polishing rate is lowered. So that the scratch value is liable to be generated.

Specific examples of the superfine fiber include aromatic poly (ethylene terephthalate), polyethylene terephthalate (PET), isophthalic acid modified polyethylene terephthalate, sulfoisophthalic acid modified polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, Ester fibers; Aliphatic polyester fibers formed by polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutylate-polyhydroxyvalerate copolymer and the like; A polyamide fiber formed of polyamide 6, polyamide 66, polyamide 10, polyamide 11, polyamide 12, polyamide 6-12 or the like; Polyolefin fibers such as polypropylene, polyethylene, polybutene, polymethylpentene, and chlorinated polyolefin; A modified polyvinyl alcohol fiber formed by modified polyvinyl alcohol containing 25 to 70 mol% of ethylene units; And elastomer fibers formed of an elastomer such as a polyurethane-series elastomer, a polyamide-series elastomer, and a polyester-series elastomer. These may be used alone or in combination of two or more. Particularly, when the microfine fibers of this embodiment are formed of polyester fibers, they are preferable in that they can form dense, high-density fiber entangled bodies.

As among the ultrafine fibers, and the glass transition temperature (T _g) is more than 50 ℃, more preferably more than 60 ℃, the absorption rate of when sikyeoteul saturated absorbent fibers are preferably formed of a thermoplastic resin is 0.2 to 2% by weight at 50 ℃ Do. When the glass transition temperature of the thermoplastic resin is in this range, it is possible to maintain a higher rigidity, so that the planarization performance is further enhanced. In addition, the rigidity is not lowered with time even during polishing and excellent in polishing stability and polishing uniformity A polishing pad is obtained. The upper limit of the glass transition temperature is not particularly limited, but is preferably in the range of 300 deg. C or less, more preferably 150 deg.

The microfine fibers of the present embodiment are preferably formed of a thermoplastic resin having an absorption rate of 0.2 to 2% by mass when absorbed and saturated at 50 占 폚. In other words, the thermoplastic resin forming the microfine fibers is preferably absorbed and saturated at 50 占 폚 It is preferable that the water absorption rate is 0.2 to 2% by mass. When the water absorption rate is 0.2 mass% or more, the polishing slurry is liable to liquefy, and the polishing efficiency and polishing uniformity are likely to be improved. When the amount is 2% by mass or less, the polishing pad does not excessively absorb the abrasive slurry, thereby further suppressing the degradation of the stiffness over time. In such a case, a polishing pad whose polishing rate and polishing uniformity are not varied well can be obtained, in which the degradation of the planarization performance over time is suppressed. The thermoplastic resin forming the microfine fibers of the present invention is preferably a polyester polymer, in particular, a semiaromatic polyester polymer in which an aromatic component is used as one ingredient of the raw material, in view of water absorption and good manufacturability in addition to water absorption .

Specific examples of the thermoplastic resin, examples thereof include e.g., polyethylene terephthalate (PET, T _g 77 ℃, referred to as the absorption rate at the time sikyeoteul saturated absorption at 50 ℃ (hereinafter simply absorption) 1% by mass), isophthalic acid-modified polyethylene terephthalate ( T _g 67 ~ 77 ℃, water absorption of 1 mass%), sulfoisophthalic acid-modified polyethylene terephthalate (T _g 67 ~ 77 ℃, absorption 1-3 mass%), polybutylene naphthalate (T _g 85 ℃, absorption rate 1% by weight) , Polyethylene naphthalate (T _g 124 deg. C, absorption rate: 1 mass%), and the like; Aromatic polyamide-based fibers formed from terephthalic acid, nonanediol and methyl octanediol copolymerized polyamide (T _g 125 ° to 140 ° C., absorption rate: 1 to 3% by mass), and the like. In particular, modified PET such as PET and isophthalic acid modified PET is largely crimped in a wet heat treatment process for forming microfine fibers from a web entangled sheet made of sea-island type composite fibers to be described later, so that dense and high- It is preferable from the viewpoints of being capable of forming a coalesced body, being easy to increase the rigidity of the polishing sheet, and hardly causing change with time due to moisture at the time of polishing.

The polishing pad according to the present embodiment preferably comprises a microfine fiber embedding body and a polymer elastic body formed from a bundle of microfine fibers to which the microfine fibers are bundled.

Specific examples of the polymeric elastomer used in the present embodiment are not particularly limited as long as they satisfy the glass transition temperature, storage elastic modulus and absorption rate described later, and examples thereof include polyurethane resins, polyamide resins, (meth) (Meth) acrylic ester-styrene resin, (meth) acrylic acid ester-acrylonitrile resin, (meth) acrylic acid ester-olefin resin, (meth) acrylic acid ester- (hydrogenated) isoprene- Styrene-butadiene-based resin, acrylonitrile-butadiene-based resin, acrylonitrile-butadiene-styrene-based resin, vinyl acetate-based resin, (meth) acrylic acid ester- Based resin, an ethylene-vinyl acetate-based resin, an ethylene-olefin-based resin, a silicone-based resin, a fluorine- By Lee ester-based resin and the like it may be made of a elastic material.

As the polymeric elastomer of the present embodiment, a hydrogen-bonding polymeric elastomer is preferable from the viewpoint of the aggregation property to microfine fibers and the constraint binding ability of a microfine fiber bundle. The resin forming the hydrogen-bonding polymeric elastomer is a polymeric elastomer which is crystallized or agglomerated by hydrogen bonding such as a polyurethane resin, a polyamide resin, a polyvinyl alcohol resin or the like. The hydrogen-bonding polymer elastomer has high adhesiveness to enhance the confinement of the fiber bundle and suppress the fiber from coming off.

The polymeric elastomer used in the present embodiment has a glass transition temperature of -10 占 폚 or lower. When the glass transition temperature is higher than -10 占 폚, the polymeric elastomer becomes fragile, the polymeric elastomer tends to fall off during polishing, and scratches are likely to occur. Further, the gathering force of the superfine fiber by the polymeric elastomer is weakened, and the stability over time in the polishing tends to deteriorate. Preferably, the glass transition temperature is -15 占 폚 or lower. The lower limit is not particularly limited, but is preferably about -100 deg. C or higher in terms of availability. Further, the glass transition temperature is calculated from the peak temperature of the loss elastic modulus in the tensile mode in the dynamic viscoelasticity measurement. Since the glass transition temperature depends on the peak temperature of the? Dispersion of the polymeric elastomer, it is preferable to appropriately select the components constituting the elastomeric polymer so that the glass transition temperature of the polymeric elastomer is -10 占 폚 or lower. For example, in the case of using a polyurethane resin as the polymeric elastomer, in order to set the glass transition temperature to -10 캜 or lower, the composition of the polyol to be a soft component, the soft component (isocyanate component or chain extender component) Select the ratio of components. Specifically, a polyol having a glass transition temperature of -10 占 폚 or lower, preferably -20 占 폚 or lower is selected and the mass ratio of the polyol component in the polyurethane is set to 30 mass% or more, preferably 40 mass% or more .

In addition, the polymer elastic body used in the present embodiment has a storage elastic modulus at 23 占 폚 and 50 占 폚 in the range of 90 to 900 MPa. The storage elastic modulus at 23 占 폚 and 50 占 폚 of a general polyurethane is less than 90 MPa. When the storage elastic modulus at 23 占 폚 and 50 占 폚 is less than 90 MPa, the elastic polymer restraining the fiber bundle is easily deformed The pad rigidity in polishing is insufficient and the planarizing property is lowered. Further, the polymeric elastomer tends to be swelled by slurry or the like during polishing, and the stability over time tends to decrease. When the storage elastic modulus in the range of 23 占 폚 and 50 占 폚 exceeds 900 MPa, the polymeric elastomer becomes fragile, the polymeric elastomer tends to fall off during polishing, and scratches are likely to occur. In addition, the gathering force of the microfine fibers is deteriorated, and the stability over time during polishing tends to deteriorate. Preferably, the storage elastic modulus in the range of 23 占 폚 and 50 占 폚 is 200 to 800 MPa. Since the storage elastic modulus of the polymeric elastomer depends on the composition of the polymeric elastomer, that is, the elastic modulus and the mass ratio of each of the hard and soft components constituting the polymeric elastomer, in order to achieve the storage elastic modulus within the above range, It is preferable to select the composition and the mass ratio thereof.

For example, when a polyurethane resin is used as the polymeric elastomer, a poly (ethylene glycol) such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol) Ether-based polyols and copolymers thereof; Polybutylene adipate diol, polybutylene sebacate diol, polyhexamethylene adipate diol, poly (3-methyl-1,5-pentylene adipate) diol, poly (3-methyl-1,5- Sebacate) diol, isophthalic acid copolymerized polyol, terephthalic acid copolymerized polyol, cyclohexanol copolymerized polyol, polycaprolactone diol and the like, and copolymers thereof; (3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, poly (methyl-1,8-octamethylene carbonate) diol, polynonan methylene carbonate Polycarbonate-based polyols such as diol and polycyclohexanecarbonate, and copolymers thereof; Polyester carbonate polyol and the like. If necessary, polyfunctional alcohols such as trifunctional alcohols such as trimethylolpropane and tetrafunctional alcohols such as pentaerythritol, and polyfunctional alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol and the like Of a single chain alcohol may be used in combination. These may be used alone or in combination of two or more. Particularly, a polycarbonate-based polyol such as alicyclic polycarbonate-based polyol, linear polycarbonate-based polyol or branched polycarbonate-based polyol is contained in an amount of 60 to 100 mass% of the total amount of the polyol component, ° C. or less is contained in an amount of 60 to 100 mass% of the total amount of the polyol component, the stability against aging during polishing is good because of the high resistance to slurry used in polishing, Or a storage elastic modulus within the range of the present embodiment.

It is preferable to select a polyol having a glass transition temperature of -10 占 폚 or lower, preferably -20 占 폚 or lower, in order to set the storage elastic modulus in the range of 23 占 폚 and 50 占 폚 in the range of 90 to 900 MPa. Specifically, for example, a polycarbonate-based polyol having the aforementioned branch; Polyether polyols such as polypropylene glycol, polytetramethylene glycol and poly (methyltetramethylene glycol), and copolymers thereof; (3-methyl-1,5-pentylene adipate) diol, poly (3-methyl-1,5-pentylenecabicate) diol and polycaprolactone diol Polyols and copolymers thereof; Polycarbonate-based polyols such as poly (3-methyl-1,5-pentylene carbonate) diol and poly (methyl-1,8-octamethylene carbonate) diol; and copolymers thereof; Polyester carbonate polyol and the like. In addition to the above-mentioned polyols, polyols having a glass transition temperature of -10 占 폚 or lower by copolymerization may be exemplified.

The polyurethane resin containing a polyalkylene glycol group having 5 or less carbon atoms, particularly 3 or less carbon atoms is preferably a polyurethane resin containing 0.1 to 10% by mass of such a polyalkylene glycol group from the standpoint that the wettability to water becomes particularly good. It is also preferable to use a resin.

(Polyol component) having a glass transition temperature of -10 DEG C or lower is used to adjust the glass transition temperature of the polyurethane to -10 DEG C or lower and to select such polyol component so that the mass ratio of the polyol component in the polyurethane is The storage modulus of the polyurethane at 23 占 폚 and 50 占 폚 can be set in the range of 90 to 900 MPa.

When a polyurethane resin is used as the polymeric elastomer, examples of the isocyanate component in the light component (isocyanate component or chain extender component) include hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 4,4'-dicyclohexyl Non-substituted diisocyanates of aliphatic or alicyclic diisocyanates typified by methane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate poly An aromatic diisocyanate represented by urethane can be used. If necessary, a polyfunctional isocyanate such as trifunctional isocyanate or tetrafunctional isocyanate may be used in combination. These may be used alone or in combination of two or more. Of these, 4,4'-dicyclohexylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate, The adhesion to the microfine fibers is high, the microfine fiber is improved in the holding power, and the polishing pad with high hardness can be obtained.

Examples of the chain extender component include diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-bis (? -Hydroxyethoxy) benzene and 1,4-cyclohexanediol; Triols such as trimethylolpropane; Pentaols such as pentaerythritol; Mono-chain polyols typified by amino alcohols such as methyl ethyl ketone, methyl ethyl ketone, cyclohexanone, methyl ethyl ketone, methyl ethyl ketone, Diamines such as isophthalic acid dihydrazide; Triamines such as diethylenetriamine; And a short chain polyamine represented by tetramines such as triethylenetetramine, etc., can be selected as a hard component having high cohesiveness and high elasticity. In the chain extension reaction, monoamines such as ethylamine, propylamine and butylamine together with a chain extender; Amino group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; (Hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,2-bis (hydroxymethyl) propanoic acid, and the like may be used in combination with monohydric alcohols such as methanol, ethanol, ) Valeric acid-containing diols or the like can be used in combination to further improve the wettability to water by introducing an ionic group such as a carboxyl group into the skeleton of the polyurethane-based elastomer.

The proportion of the soft component (polyol component) is preferably from 40 to 65 mass%, more preferably from 45 to 60 mass%, from the viewpoint of keeping the storage elastic modulus of the polyurethane at 23 占 폚 and 50 占 폚 in the range of 90 to 900 MPa % By mass is more preferable. When the amount of the soft component is less than 40% by mass, the temperature dependency of the storage modulus in the range of 23 占 폚 and 50 占 폚 becomes high, and it is difficult to be in the range of 90 to 900 MPa. On the other hand, when the amount of the soft component exceeds 65% by mass, the storage elastic modulus tends to be less than 90 MPa.

As the soft component, a polycarbonate polyol having a branch particularly in view of easily increasing the storage modulus of the polyurethane; Poly (3-methyl-1,5-pentylene carbonate) diol, poly (methyl-1,8-octamethylenecarbonate) 1,8-octamethylene carbonate), polycarbonate polyol copolymerizing polycarbonate polyol such as polyhexamethylene carbonate diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, polynonan methylene carbonate diol, polycyclohexanecarbonate, etc. Representative polycarbonate-based polyols are preferred.

Further, the polymeric elastomer of the present embodiment preferably has a ratio of a storage elastic modulus at 23 占 폚 and a storage elastic modulus at 50 占 폚 (storage elastic modulus at 23 占 폚 / storage elastic modulus at 50 占 폚) of 4 or less. When the ratio of the storage elastic modulus at 23 占 폚 and the storage elastic modulus at 50 占 폚 (storage elastic modulus at 23 占 폚 / storage elastic modulus at 50 占 폚) is 4 or less, And the stability over time during polishing is improved. In particular, it is preferable that the ratio of the storage elastic modulus at 23 ° C and the storage elastic modulus at 50 ° C (storage elastic modulus at 23 ° C / storage elastic modulus at 50 ° C) is 3 or less. The lower limit is not particularly limited, but is preferably 1/3 or more from the viewpoint that the storage modulus change due to the temperature during polishing hardly occurs.

The above range can be attained by suitably adjusting the soft component or the hard component for the range of the storage elastic modulus.

For example, when a polyurethane-based resin is used as the polymeric elastomer, a soft component (polyol component) having a glass transition temperature of -10 占 폚 or lower is used, the glass transition temperature of the polyurethane is set to -10 占 폚, (Isocyanate component or chain extender component), alicyclic diisocyanates or aromatic diisocyanates and mono-chain polyamines such as diols, triols and pentahols, diamines, triamines, and tetramines, , And the ratio of the soft component is preferably from 40 to 65% by mass, more preferably from 45 to 60% by mass. As the soft component, a polycarbonate-based polyol is preferable as the soft component in that the modulus of elasticity of the polyurethane can easily be increased.

As the polymeric elastomer, two or more kinds of elastomeric polymers may be contained in order to control the performance of the polishing pad and the composition. In this case, the storage elastic modulus of the elastomeric polymer at 23 DEG C to 50 DEG C, And the value obtained by multiplying the mass fraction by the mass fraction.

The polymeric elastomer of the present embodiment has an absorption rate of 0.2 to 5% by mass when absorbed and saturated at 50 占 폚. When the water absorption rate is less than 0.2 mass%, it is difficult to maintain the polishing slurry and the polishing efficiency and polishing uniformity are liable to be lowered. If it exceeds 5% by mass, a change with time in the abrasion tends to increase due to absorption softening of the elastomeric polymer restraining the fiber bundle. The absorption rate when absorbed and saturated at 50 占 폚 is preferably in the range of 0.5 to 3 mass%. When the water absorption rate of the polymeric elastomer is in this range, the high wettability of the abrasive slurry with respect to the polishing pad at the time of polishing can be maintained, and the stiffness can be further suppressed from being lowered over time. As a result, a high polishing rate can maintain polishing uniformity and polishing stability.

The absorption rate of the polymeric elastomer is, as will be described later in detail, the rate of absorption when the polymeric elastomer film dried is dipped in water at room temperature and saturated and swollen. When two or more polymeric elastomers are contained, theoretically can be calculated as the sum of values obtained by multiplying the absorption rate of each polymeric elastomer by the mass fraction.

The polymeric elastomer having such a water absorption rate can be achieved by adjusting the composition and cross-linking density of the polymer constituting the polymeric elastomer, introducing a hydrophilic functional group, and selecting the amount.

For example, the water absorption and hydrophilicity can be adjusted by introducing at least one hydrophilic group selected from the group consisting of carboxyl group, sulfonic acid group and polyalkylene glycol group having 3 or less carbon atoms into the polymeric elastomer. Thus, the wettability of the polishing pad to the abrasive slurry at the time of polishing can be improved. Such a hydrophilic group can be introduced into a polymeric elastomer by copolymerizing a monomer component having a hydrophilic group as a monomer component in producing a polymeric elastomer. The copolymerization ratio of the monomer component having such a hydrophilic group is preferably from 0.1 to 10 mass%, more preferably from 0.5 to 5 mass% from the viewpoint of increasing the water absorption and wettability while minimizing the swelling softening due to absorption.

The polymeric elastomer may be used alone or in combination of two or more. Among these, polyurethane-based resins are preferable because they are excellent in adhesiveness for bundling ultrafine fibers or binding and binding together bundles of fibers, and are excellent in long-term stability in polishing by increasing the hardness of the polishing pad . It is preferable that the polyurethane resin having at least one hydrophilic group selected from the group consisting of a carboxyl group, a sulfonic acid group and a polyalkylene glycol group having 3 or less carbon atoms has a high stiffness, wettability and stability over time during polishing .

When the polymeric elastomer is a polyurethane resin, specific examples of the carboxyl group include 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,2-bis (hydroxymethyl) Valeric acid, and the like, and diols containing these carboxyl groups can be used in combination to introduce a carboxyl group into the skeleton of the polyurethane-based elastomer. Specific examples of the polyalkylene glycol group having 3 or less carbon atoms include polyethylene glycol, polypropylene glycol and copolymers thereof. A polyurethane resin having at least one hydrophilic group selected from the group consisting of a carboxyl group, a sulfonic acid group and a polyalkylene glycol group having 3 or less carbon atoms tends to have an increased water absorption, but tends to have an increased water absorption, The water absorption is 5 to 15 mass%. Therefore, in order to achieve an absorption rate of 0.2 to 5% by mass in the present embodiment, the amount of at least one hydrophilic group selected from the group consisting of a carboxyl group, a sulfonic acid group and a polyalkylene glycol group having 3 or less carbon atoms is preferably 0.1 to 10% , More preferably from 0.5 to 5% by mass, and further, as the polyol, it is preferable to use a component having low water absorption, for example, the above-mentioned polyester-based polyol or polycarbonate polyol.

For example, when the polymeric elastomer is a polyurethane-based resin obtained by using a polycarbonate-based diol as a polyol component and a carboxyl-containing diol as a diol component and using an alicyclic diisocyanate as a diisocyanate component, the glass transition of the polymeric elastomer It is easy to set the temperature to -10 占 폚 or less, the storage elastic modulus at 23 占 폚 and 50 占 폚 to 90 to 900 MPa, and the absorption rate when absorption saturated at 50 占 폚 to 0.2 to 5 mass% It is preferable to use a polymeric elastomer.

As the hard component (isocyanate component or chain extender component) of the polyurethane resin used in the present invention, for example, the chain extender component having high cohesiveness with the isocyanate component can be selected. The proportion of the soft component (polyol component) is preferably 65% by mass or less, more preferably 60% by mass or less. If the amount of the soft component exceeds 65% by mass, the water absorption rate tends to be high. When the polymeric elastomer is an aqueous polyurethane, the water-soluble polyurethane preferably has an average particle diameter of 0.01 to 0.2 탆 in order to obtain an absorption rate of 0.2 to 5% by mass. When the thickness is 0.01 μm or less or 0.2 μm or more, the water absorption rate tends to exceed 5% by mass.

When the polymeric elastomer is a polyurethane resin, a crosslinking agent containing two or more functional groups capable of reacting with the functional group of the monomer unit forming the polyurethane in the molecule or a crosslinking agent containing a polyisocyanate It is also preferable to form a crosslinked structure by adding a self-crosslinking compound such as a system compound or a polyfunctional block isocyanate compound.

The combination of the functional group of the monomer unit and the functional group of the crosslinking agent includes a combination of a carboxyl group and an oxazoline group, a carboxyl group and a carbodiimide group, a carboxyl group and an epoxy group, a carboxyl group and a cyclocarbonate group, a carboxyl group and an aziridine group, a carbonyl group and a hydrazide derivative or a hydrazide derivative And the like. Among these, a combination of a monomer unit having a carboxyl group and a crosslinking agent having an oxazoline group, a carbodiimide group or an epoxy group, a combination of a monomer unit having a hydroxyl group or an amino group and a crosslinking agent having a block isocyanate group and a combination of a monomer unit having a carbonyl group with a hydrazine A derivative or a hydrazide derivative is particularly preferable because it is easy to form a crosslink and the rigidity and abrasion resistance of the obtained polishing pad are excellent. It is preferable that the crosslinked structure is formed in the heat treatment step after impregnating the fiber entangled body with the aqueous solution of the polyurethane resin in order to maintain the stability of the aqueous liquid of the elastomeric polymer. Among them, a carbodiimide group and / or an oxazoline group which is excellent in the crosslinking performance and the port life of the aqueous liquid and does not cause any problems in terms of safety are particularly preferable. As the crosslinking agent having a carbodiimide group, for example, a water-dispersed carbodiimide compound such as "Carbodilite E-01", "Carbodite E-02", "Carbodilite V- . Examples of the cross-linking agent having an oxazoline group include water-dispersed oxazoline compounds such as "Epochros K-2010E", "Epochros K-2020E" and "Epocross WS-500" manufactured by Nippon Catalysts Co., have. The blending amount of the crosslinking agent is preferably from 1 to 20 mass%, more preferably from 1.5 to 10 mass%, of the effective component of the crosslinking agent with respect to the polyurethane resin.

It is also possible to increase the rigidity of the fiber bundle by increasing the adhesiveness with the ultrafine fibers, to set the glass transition temperature to -10 占 폚 or lower, to set the storage modulus at 23 占 폚 and 50 占 폚 in the range of 90 to 900 MPa , And that the absorption rate when absorbed and saturated at 50 占 폚 is 0.2 to 5 mass% is easily adjusted, the content of the polyol component in the polyurethane resin is preferably 65 mass% or less, more preferably 60 mass% or less Do. Further, it is preferable that the content is 40 mass% or more, and more preferably 45 mass% or more, because the generation of scratches can be suppressed by giving appropriate elasticity.

The polyurethane resin can be incorporated with various additives such as a penetrating agent, an antifoaming agent, a lubricant, a water repellent agent, a bleaching agent, a thickener, an extender, a curing accelerator, an antioxidant, an ultraviolet absorber, Alcohol, carboxymethylcellulose, and other water-soluble polymer compounds, dyes, pigments, inorganic fine particles, and the like.

It is preferable that the polymeric elastomer be present in the microfine fiber bundles in which 5 to 70 microfine fibers having an average fineness of 0.01 to 0.8 dtex or less forming microfine fiber embryos are bundled. The microfine fibers are collected by the elastic polymer existing inside the microfine fiber bundle. When the microfine fibers are collected, a part or the whole of the fiber bundle is collected and the microfine fiber bundle is confined. It is preferable that the superfine fiber bundle is constrained while the superfine fiber bundle is concentrated because it increases the rigidity of the polishing pad and improves the planarization performance, the polishing uniformity and the stability over time.

The presence of voids in the polishing pad in a range of 40 to 95%, that is, a porosity of 5 to 60%, in terms of the volume ratio of the portion excluding the void (hereinafter also referred to as the polishing pad filling rate) In view of having both adequate stiffness and liquid retention.

In this case, if the porosity of the polishing pad impregnated with the polymeric elastomer is 50% or more, it is preferable from the viewpoint of excellent slurry lubrication property, moderate rigidity and further cushioning property in view of excellent bare silicon wafer polishing, Is preferably 70% or less in view of excellent polishing rate and flatness in rough polishing represented by bare silicon wafer polishing.

It is more preferable that a part of the voids form a communication hole communicating with the inside of the polishing pad because the slurry lyophobicity is improved.

The polymeric elastomer is preferably an aqueous polyurethane in view of good wettability of the polishing slurry, and the aqueous polyurethane preferably has an average particle diameter of 0.01 to 0.2 μm. When the average particle diameter is 0.01 탆 or more, the water resistance is good and the stability over time during polishing is excellent. When the average particle diameter is 0.2 占 퐉 or less, the binding force of the fiber bundle is improved and the planarizing property is excellent, and the life of the pad during polishing is prolonged, and the stability over time is excellent. In order to adjust the particle diameter, it is preferable that the polymeric elastomer contains at least one kind of hydrophilic group selected from the group consisting of a carboxyl group, a sulfonic acid group and a polyalkylene glycol group having 3 or less carbon atoms.

The ratio of the microfine fiber embedding body and the polymer elastomer (microfine fiber entanglement / polymer elastomer) is preferably 55/45 to 95/5 by mass ratio. When the mass ratio of the microfine fiber embroidery body is 55% or more, the stability over time during polishing is excellent, and the polishing efficiency tends to be improved. When the mass ratio of the microfine fiber ambipacity is 95% or less, the binding force of the polymer elastic body in the fiber bundle is maintained, and the flatness is excellent and the pad wear during polishing is reduced. Particularly, the ratio of the microfine fiber scaffold to the polymeric elastomer is preferably in the range of 60/40 to 90/10 by mass ratio.

The apparent density of the polishing pad of the present embodiment is preferably in the range of 0.4 to 1.2 g / cm 3, more preferably 0.5 to 1.0 g / cm 3, in view of keeping the slurry retainability favorable and keeping the rigidity high Do. In the case of bare silicon wafer polishing, it is preferably 0.3 to 0.75 g / cm 3, more preferably 0.4 to 0.65 g / cm 3, in view of enhancing the polishing rate and having flatness.

In the present embodiment, the average length of the microfine fiber bundles is not particularly limited, but it is preferably 100 mm or more, more preferably 200 mm or more, to easily increase the fiber density of the microfine fibers, It is preferable from the viewpoint that it is possible to increase the tensile strength and to prevent the fiber from coming off. When the length of the fiber bundle is too short, it is difficult to increase the density of the superfine fiber, and a sufficiently high rigidity can not be obtained, and the superfine fiber tends to be easily removed during polishing. The upper limit is not particularly limited. For example, in the case of containing a fibrous article derived from a nonwoven fabric produced by a spunbond method described below, the upper limit is preferably in the range of several meters, several hundred meters, Further fiber lengths may be included.

The polishing pad of the present embodiment preferably has a structure in which the fibrous article is filled with a polymeric elastomer and compounded.

In the polishing pad of the present embodiment, it is preferable that the polymeric elastomer be present in the microfine fiber bundle from the standpoint of enhancing the rigidity of the polishing pad, and it is more preferable that the microfine fibers forming the microfine fiber bundle are collected by the polymeric elastomer Do. As described above, the rigidity of the polishing pad is further increased because the microfine fibers are concentrated. Each of the microfine fibers does not move smoothly due to the concentration of the microfine fibers, and the rigidity of the polishing pad is increased, so that high planarization performance tends to be obtained. In addition, it is possible to prevent the aggregation of the abrasive grains on the missing fibers due to the decrease of the fiber dropout, thereby preventing the scratches from being generated well. Here, the fact that the microfine fibers are collected means that most of the microfine fibers existing in the microfine fiber bundle (preferably at least 10%, more preferably at least 20%, more preferably at least 50% Or more, more than 60%) is adhered and bound by a polymeric elastomer present in the microfine fiber bundle.

It is also preferable that a plurality of microfine fiber bundles are bound to each other by a polymeric elastomer existing outside the microfine fiber bundles and exist in a lump (bulk) form. As described above, by bonding the microfine fiber bundles together, the shape stability of the polishing pad is improved and the polishing stability is improved.

The focusing and constraining states of the microfine fibers and the binding state between the microfine fiber bundles can be confirmed by electron micrographs of the cross section of the polishing pad.

The polymeric elastomer body which bundles the ultrafine fibers and the polymeric elastomer body which binds the ultrafine fiber bundles are preferably non-porous. In addition, the non-porous shape means a state in which substantially no voids (independent bubbles) are present as in the porous shape or the polymer elastic body of the sponge shape (hereinafter simply referred to as porous shape). Specifically, it means that it is not a polymeric elastomer having many fine bubbles, for example, obtained by solidifying a solvent-based polyurethane. In the case where the polymeric elastomer that is focused or bound is nonporous, the polishing stability is enhanced and slurry debris or pad debris upon polishing does not deposit well on the pores. Therefore, the polymer is not abraded and a high polishing rate is maintained for a long time . In addition, since the bonding strength to the microfine fibers is high, it is possible to suppress the occurrence of scratches due to the fiber coming off. In addition, since a higher rigidity can be obtained, a polishing pad having excellent planarization performance can be obtained.

The polishing pad of the present embodiment preferably has a water absorption rate of 10 to 80% by mass, more preferably 15 to 70% by mass when swelled with hot water at 50 캜. When the water absorption rate is 10 mass% or more, the abrasive slurry is easily retained, the polishing rate is improved, and the polishing uniformity tends to be improved. When the water absorption rate is 80% by mass or less, a high polishing rate is obtained, and characteristics such as hardness are not changed during polishing, so that the stability of the planarization performance tends to be excellent over time.

The polishing pad of the present embodiment can be applied to various types of polishing apparatuses such as a pad flattening treatment by buffing or the like, a pre-polishing seasoning treatment (conditioning treatment) using a pad dressing such as a diamond or a dressing treatment at polishing, The fibrillated or fibrillated microfine fibers can be formed on the surface of the polishing pad. The fiber density of the superfine fiber on the surface of the polishing pad is preferably not less than 600 / mm 2, more preferably not less than 1,000 / mm 2, particularly not less than 2000 / mm 2. When the fiber density is too low, the retention of abrasive grains tends to become insufficient. The upper limit of the fiber density is not particularly limited, but is about 1,000,000 / mm 2 in terms of productivity. The microfine fibers on the surface of the polishing pad may be napped or not napped. When the superfine fibers are worn, the surface of the polishing pad is softened, so that the scratch reduction effect is further enhanced. On the other hand, when the degree of napping of microfine fibers is low, it is advantageous for applications emphasizing micro flatness. It is preferable to appropriately select the surface state depending on the application.

[Manufacturing method of polishing pad]

Next, an example of a method of manufacturing the polishing pad of the present embodiment will be described in detail.

The polishing pad of the present embodiment can be produced by, for example, a web manufacturing process for producing a long-fiber web composed of sea-island composite fibers obtained by melt-spinning a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin, A wet heat shrink treatment step of shrinking the web misalignment sheet so that the area shrinkage ratio is 30% or more by shrinking the web misalignment sheet by wet heat; and a wet heat shrink treatment step of shrinking the web- And a polymeric elastomer filling step of impregnating and drying and solidifying the aqueous liquid of the elastomeric polymer in the fiber entangled body by a method of producing a polishing pad comprising the step of forming a fiber mantle composed of microfine fibers Can be obtained.

In the above production method, by subjecting the web entangled sheet containing long fibers to a wet heat shrinkage process, the web entangled sheet can be shrunk to a large extent as compared with wet heat shrinking the web entangled sheet containing short fibers, , The fiber density of the microfine fibers becomes dense. Then, a water entangled thermoplastic resin of the web offset sheet is dissolved and extracted to form a fiber entangled body composed of microfine fiber bundles. At this time, voids are formed in the portion where the water-soluble thermoplastic resin is dissolved and extracted. By sufficiently impregnating this void with an aqueous solution of a high-molecular elastomer in a high concentration and drying and solidifying, the microfine fibers constituting the microfine fiber bundle are concentrated and the microfine fiber bundles are also concentrated. In this manner, a polishing pad having high fiber density, low porosity, and high rigidity, in which ultrafine fibers are gathered, is obtained.

The porosity of the polishing pad is adjusted to not less than 50% by adjusting the amount of the elastic polymer impregnated in the shrinkage treatment or the gap so that the bare silicon wafer having proper stiffness and improvement in the retention and cushioning properties of the abrasive slurry, Is obtained.

Each step will be described in detail below.

(1) Web manufacturing process

In this step, first, a long-fiber web composed of sea-island conjugate fibers obtained by melt-spinning a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin is produced.

The above-mentioned sea-island type conjugate fiber is obtained by melt spinning a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin having low compatibility with the water-soluble thermoplastic resin, and then compounding them. Then, the water-soluble thermoplastic resin is dissolved, removed or decomposed from the sea type conjugate fiber to form microfine fibers. The thickness of the sea-island composite fiber is preferably 0.5 to 3 decitex from the viewpoint of industrial efficiency.

In addition, in the present embodiment, the sea-island composite fiber as the composite fiber for forming the ultrafine fiber is described in detail, but a known ultrafine fiber-generating fiber such as multi-layer laminated cross-section fiber may be used in place of the sea- .

As the water-soluble thermoplastic resin, a resin capable of melt-spinning is preferably used as a thermoplastic resin that can be dissolved or removed by dissolution or decomposition with water, an alkaline aqueous solution, an acidic aqueous solution or the like. Specific examples of such water-soluble thermoplastic resins include polyvinyl alcohol resins (PVA resins) such as polyvinyl alcohol and polyvinyl alcohol copolymer; Modified polyesters containing polyethylene glycol and / or an alkali metal sulfonate as copolymer components; Polyethylene oxide, and the like. Of these, PVA resins are particularly preferably used for the following reasons.

When the sea-island composite fiber comprising the PVA-based resin as a water-soluble thermoplastic resin component is used, the ultrafine fibers formed by dissolving the PVA-based resin are largely crimped. As a result, fiber bundles having a high fiber density can be obtained. In the case of using a sea-island composite fiber comprising a PVA resin as a water-soluble thermoplastic resin component, the ultrafine fibers and the elastomeric polymer to be formed are not substantially decomposed or dissolved when the PVA resin is dissolved. The physical properties of the material do not deteriorate. Also, the environmental load is small.

The PVA resin is obtained by saponifying a copolymer containing a vinyl ester unit as a main component. Specific examples of the vinyl monomer for forming the vinyl ester unit include vinyl monomers such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, Vinyl, and vinyl palmitate. These may be used alone or in combination of two or more. Of these, vinyl acetate is preferable from the viewpoint of industrial applicability.

The PVA resin may be a homo PVA comprising only a vinyl ester unit or a modified PVA containing a copolymer monomer unit other than a vinyl ester unit as a constituent unit. Modified PVA is more preferable in that it can control melt spinnability, water solubility, and fiber property. Specific examples of the copolymerizable monomer unit other than the vinyl ester unit include, for example,? -Olefins having 4 or less carbon atoms such as ethylene, propylene, 1-butene, and isobutene; And vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether and n-butyl vinyl ether. The content of the copolymerizable monomer unit other than the vinyl ester unit is preferably from 1 to 20 mol%, more preferably from 4 to 15 mol%, particularly preferably from 6 to 13 mol%. Among these, the ethylene-modified PVA containing 4 to 15 mol%, more preferably 6 to 13 mol% of ethylene units is preferable in that the physical properties of the sea-island conjugate fiber are enhanced.

The viscosity average degree of polymerization of the PVA resin is preferably in the range of 200 to 500, more preferably in the range of 230 to 470, in particular in the range of 250 to 450. It is preferable that the PVA resin has a stable sea structure, It is preferable that the dissolution rate is high. The polymerization degree is measured according to JIS-K6726. Namely, after the PVA resin is re-saponified and purified, it is determined from the intrinsic viscosity [?] Measured in water at 30 ° C according to the following formula.

Viscosity average degree of polymerization P = ([?] X103 / 8.29) (1 / 0.62)

The degree of saponification of the PVA resin is preferably in the range of 90 to 99.99 mol%, more preferably 93 to 99.98 mol%, particularly 94 to 99.97 mol%, particularly 96 to 99.96 mol%. When the degree of saponification is in this range, a PVA resin excellent in water solubility, good in thermal stability, excellent in melt spinnability, and excellent in biodegradability can be obtained.

The melting point of the PVA resin is preferably in the range of 160 to 250 ° C, more preferably 170 to 227 ° C, particularly preferably 175 to 224 ° C, particularly preferably 180 to 220 ° C because of its excellent mechanical properties and thermal stability, It is preferable in terms of excellence. When the melting point of the PVA-based resin is too high, the melting point and the decomposition temperature are close to each other. Therefore, when the PVA-based resin is decomposed during melt spinning, the melt spinnability tends to decrease.

When the melting point of the PVA resin is too low as compared with the melting point of the water-insoluble thermoplastic resin, the melt spinnability is not preferable. From such a viewpoint, it is preferable that the melting point of the PVA-based resin is not higher than 60 占 폚, and furthermore, not lower than 30 占 폚 in excess of the melting point of the water-insoluble thermoplastic resin.

As the above-mentioned water-insoluble thermoplastic resin, a resin capable of melt-spinning is preferably used as a thermoplastic resin which is not dissolved, removed or decomposed by water, an alkaline aqueous solution, an acidic aqueous solution or the like.

As specific examples of the water-insoluble thermoplastic resin, various thermoplastic resins used for forming the microfine fibers constituting the polishing pad described above can be used.

The water-insoluble thermoplastic resin may contain various additives. Specific examples of the additive include, for example, a catalyst, a coloring preventing agent, a heat resistant agent, a flame retardant, a lubricant, an antifouling agent, a fluorescent whitening agent, a gloss removing agent, a colorant, a gloss improver, an antistatic agent, a fragrance, a deodorant, Inorganic fine particles, and the like.

Next, a method of forming a sea-island composite fiber by melt-spinning the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin, and forming a long-fiber web from the obtained sea-island composite fiber will be described in detail.

The long-fiber web can be obtained, for example, by compounding the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin by melt spinning, followed by stretching and depositing by the span bond method. Thus, by forming the web by the spunbond method, it is possible to obtain a long-fiber web composed of the sea-island conjugate fiber having less fiber dropout and higher fiber density and better shape stability. Also, the long fiber is a fiber produced without the cutting step as in the production of the staple fiber.

In the production of sea-island composite fibers, the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin are respectively melt-spun and composite. The mass ratio of the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin is preferably in the range of 5/95 to 50/50, more preferably 10/90 to 40/60. When the mass ratio of the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin is in this range, a high-density fiber entangled body is obtained, and the formation of microfine fibers is also excellent.

A method of forming a long-fiber web by spunbonding after complexing a water-soluble thermoplastic resin and a water-insoluble thermoplastic resin by melt spinning will be described in detail below.

First, the water-soluble thermoplastic resin and the water-insoluble thermoplastic resin are melt-kneaded by different extruders, respectively, and the strands of the molten resin are simultaneously discharged from the different spinnerets. Then, the discharged strands are combined with a composite nozzle, and then discharged from a nozzle hole of the spinning head to form a sea-island composite fiber. In the melt-mixed spinning, the number of islands of the sea-island complex fiber is 4 to 4000 degrees / fiber, more preferably 10 to 1000 degrees / fiber, the fiber bundle having a small fiber fineness and a high fiber density Is preferable.

The sea-island type conjugate fiber is cooled by a cooling device, and then drawn by a high-speed air stream at a speed corresponding to a take-off speed of 1000 to 6000 m / min so as to obtain a desired fineness using a suction device such as an air jet nozzle. Thereafter, the elongated composite fiber is deposited on the mobile collecting surface to form a long fiber web. At this time, the deposited long-fiber web may be partially pressed as needed. The weight per unit area of the fibrous web is preferably in the range of 20 to 500 g / m < 2 >

(2) Web entangling process

Next, a web entangling step of forming a web entangled sheet by making a plurality of the long webs thus obtained are entangled to each other will be described.

The web entangled sheet is formed by subjecting a long fiber web to entanglement treatment using a known nonwoven fabric manufacturing method such as needle punching and high pressure water treatment. Hereinafter, as a representative example, the entanglement process by the needle punch will be described in detail.

First, a long-fiber web is imparted with a silicone oil or mineral oil oil emulsion such as a needle-breaking anti-tack agent, an antistatic oil-repellent agent, Further, in order to reduce unevenness in weight, two or more fiber webs may be overlapped by a cross wrapper to give an emulsion.

Thereafter, for example, entanglement treatment for entangling fibers three-dimensionally by a needle punch is carried out. By performing the needle punching treatment, a web entangled sheet having a high fiber density and not causing fibers to be separated easily can be obtained. The weight per unit area of the web offset sheet is appropriately selected according to the intended polishing pad thickness and the like. Specifically, for example, a range of 100 to 1500 g / m 2 is preferable because of excellent handling properties .

The conditions such as the type and amount of the emulsion and the needle conditions such as the needle shape, the needle depth, and the number of punches in the needle punch are appropriately selected so that the delamination strength of the web entangled sheet is increased. The number of barbs is preferably in a range that does not cause needle breakage, and specifically, for example, it is selected from 1 to 9 barbs. The needle depth is preferably set in such a range that the bar passes through the overlapping web surface and the shape of the web surface after needle punching does not appear strongly. The number of needle punches is adjusted depending on the needle shape, the kind of emulsion, the amount of use, and the like. Specifically, it is preferably 500 to 5000 punch / cm 2. It is also possible to obtain a fibrous article having a high fiber density by performing entanglement treatment so that the weight per unit area after the entanglement treatment is 1.2 times or more, and more preferably 1.5 times or more, by mass per unit area before the entanglement treatment, Can be reduced. The upper limit is not particularly limited, but is preferably 4 times or less in order to avoid an increase in manufacturing cost due to a decrease in processing speed.

In the case of using a polishing pad for polishing a bare silicon wafer, it is preferable to set the porosity of the polishing pad to not less than 50%. For this purpose, the filling density of the polymeric elastomer may be adjusted depending on whether the fiber density is increased or decreased .

The delamination strength of the web interlaced sheet is preferably 2 kg / 2.5 cm or more, more preferably 4 kg / 2.5 cm or more in view of good form retentivity, less fiber dropout and fiber density, Do. Further, the interlayer peeling force is a standard for the degree of three-dimensional misalignment. When the interlayer peeling force is too small, the fiber density of the fiber scraper is not sufficiently high. The upper limit of the interlayer peel strength of the entangled nonwoven fabric is not particularly limited, but is preferably 30 kg / 2.5 cm or less in terms of entanglement treatment efficiency.

For the purpose of controlling the hardness of the polishing pad, knitted fabrics or woven fabrics (knitted fabrics) made of ultrafine fibers may also be added to the web entangled sheet, which is a nonwoven fabric obtained as described above, And the laminated structure such as an entangled nonwoven fabric / knitted fabric / entangled nonwoven fabric, which is an entangled nonwoven fabric such as a knitted fabric / entangled nonwoven fabric and an entangled nonwoven fabric, It may be used as an entangled sheet.

The ultrafine fibers constituting the knitted fabric are not particularly limited. Specifically, polyester-based fibers formed of, for example, polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate (PBT), polyester elastomer, or the like; Polyamide-based fibers formed of polyamide 6, polyamide 66, aromatic polyamide, polyamide elastomer, and the like; A urethane-based polymer, an olefin-based polymer, an acrylonitrile-based polymer, or the like is preferably used. Among them, fibers formed of PET, PBT, polyamide 6, polyamide 66, and the like are preferable from the industrial viewpoint.

Specific examples of the removal component of the sea-island composite fibers forming the knitted fabric include polystyrene and its copolymers, polyethylene, PVA resins, copolymerized polyesters and copolymerized polyamides. Of these, PVA-based resins are preferably used because they cause large shrinkage upon dissolution and removal.

(3) Heat shrinkage treatment process

Next, the wet heat shrink treatment process for increasing the fiber density and the degree of entanglement of the web entangled sheet by wet heat shrinkage of the web entangled sheet will be described. Further, in the present step, by wet heat shrinking the web-entangled sheet containing long fibers, the web entangled sheet can be shrunk to a large extent as compared with the case where the web entangled sheet containing short fibers is subjected to wet heat shrinkage, Is particularly high.

The moist heat shrinkage treatment is preferably carried out by steam heating. As the steam heating condition, the heat treatment is preferably performed for 60 to 600 seconds at an ambient temperature of 60 to 130 DEG C, at a relative humidity of 75% or more, and furthermore, at a relative humidity of 90% or more. In the case of such a heating condition, the web offset sheet can be shrunk to a high shrinkage ratio, which is preferable. In addition, when the relative humidity is too low, the moisture in contact with the fibers tends to dry quickly, resulting in insufficient shrinkage.

The wet heat shrinkage treatment preferably shrinks the web interlocking sheet so that the area shrinkage ratio is 30% or more, preferably 35% or more, and more preferably 40% or more. By contracting at such a high shrinkage ratio, a high fiber density can be obtained. The upper limit of the area shrinkage ratio is not particularly limited, but is preferably about 80% or less from the viewpoint of the shrinkage limit and the treatment efficiency.

The area shrinkage percentage (%) is represented by the following formula (1):

(Area of the sheet surface before the shrinkage treatment - area of the sheet surface after the shrinkage treatment) / area of the sheet surface before the shrinkage treatment x 100 ... (1). The area means the average area of the area of the sheet surface and the area of the back surface.

The web entangled sheet having undergone the wet heat shrinkage treatment can adjust the porosity by heating roll or hot press at a temperature higher than the heat distortion temperature of the sea-island composite fiber, and by increasing the heat press condition, the fiber density can be increased and densified.

The change in the weight per unit area of the web offset sheet before and after the wet heat shrinkage treatment is preferably such that the weight per unit area after the shrinkage treatment is 1.2 times (mass ratio) or more, more preferably 1.5 times or more, 4 times or less, and more preferably 3 times or less.

(4) Fiber bundle binding process

For the purpose of enhancing the morphological stability of the web misalignment sheet or adjusting or reducing the porosity of the resulting polishing pad prior to the microfibrous treatment of the web misalignment sheet, The fiber bundle may be stuck in advance by impregnating and drying and solidifying the aqueous liquid of the elastic body.

In the present step, the web-entangled sheet subjected to the shrinkage treatment is impregnated with the aqueous liquid of the polymeric elastomer, and then dried and solidified to fill the web entangled sheet with the polymeric elastomer. Since the aqueous liquid of the polymeric elastomer has a low viscosity even at a high concentration and is excellent in impregnation permeability, it is easily filled inside the web interlaced sheet. Also, it has excellent adhesion to fibers. Therefore, by carrying out this step, it is possible to strongly constrain the sea-island conjugate fiber.

The aqueous liquid of a polymeric elastomer is an aqueous dispersion obtained by dissolving a component forming a polymeric elastomer in an aqueous medium or an aqueous dispersion in which a component forming a polymeric elastomer is dispersed in an aqueous medium. The aqueous dispersion also includes a suspension dispersion and an emulsion dispersion. Particularly, it is more preferable to use an aqueous dispersion because of its excellent water resistance.

The method of using a polyurethane resin as an aqueous solution or an aqueous dispersion is not particularly limited and a known method can be used. Specifically, for example, a method of imparting dispersibility to an aqueous medium to a polyurethane resin by containing a monomer unit having a hydrophilic group such as a carboxyl group, a sulfonic acid group or a hydroxyl group, or a method of adding a surfactant to a polyurethane resin Followed by emulsification or suspension. Such an aqueous polymeric elastomer is excellent in wettability to water, and thus has excellent properties of maintaining abrasive grains uniformly and in a large amount.

Specific examples of the surfactant used in the emulsification or suspension include, for example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene tridecyl ether acetate, sodium dodecylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, Anionic surfactants such as sodium octylsulfosuccinate; And nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene-polyoxypropylene block copolymer. A so-called reactive surfactant having reactivity may also be used. In addition, by appropriately selecting the blur point of the surfactant, thermal gelling property can be imparted to the polyurethane resin. However, when a surfactant is used in a large amount, the polishing performance and stability with time may be adversely affected. Therefore, it is preferable that the surfactant is minimized.

The porosity can be lowered by setting the solid content concentration of the aqueous liquid of the polymeric elastomer to 10% by mass or more, more preferably 15% by mass or more.

Examples of the method for impregnating the web offset sheet with an aqueous solution of a polymeric elastomer include a method using a knife coater, a bar coater, a roll coater, or a dipping method.

The polymeric elastomer can be solidified by drying the web offset sheet impregnated with the aqueous solution of the polymeric elastomer. Examples of the drying method include a method of performing heat treatment in a drying apparatus at 50 to 200 ° C, a method of heating in an air dryer after infrared heating, and the like.

Further, in the case where the web-entangled sheet is impregnated with an aqueous solution of a polymeric elastomer and then dried, the aqueous solution may migrate (migrate) to the surface layer of the web-entangled sheet, so that a uniformly charged state may not be obtained. In such a case, adjusting the particle diameter of the polymeric elastomer of the aqueous liquid; Adjusting the kind and amount of the ionic group of the polymeric elastomer, or adjusting the stability thereof by pH or the like; A combination type thermal gelling agent such as mono- or di-valent alkali metal salt or alkaline earth metal salt, nonionic emulsifier, associative water-soluble thickener and water-soluble silicone compound, water-soluble polyurethane compound or organic or inorganic substance changing pH by heat To lower the water dispersion stability at about 40 to 100 캜; The migration can be suppressed. If necessary, the polymeric elastomer may be migrated so as to be localized on the surface.

(5) Microfiber fiber formation process

Next, the microfine fiber formation step, which is a step of forming microfine fibers by dissolving the water-soluble thermoplastic resin in hot water, will be described.

This step is a step of forming microfine fibers by removing the water-soluble thermoplastic resin. At this time, voids are formed in the portion where the water-soluble thermoplastic resin of the web misalignment sheet is dissolved and extracted. The superfine fibers are collected by filling the void with a polymeric elastomer in a polymeric elastomer filling step later. Also, bundles of microfine fibers are constrained.

The ultrafine fibrous treatment is a treatment for dissolving, removing or decomposing a water-soluble thermoplastic resin by subjecting a web entangled sheet or a composite of a web entangled sheet and a polymeric elastomer to hot water heat treatment with water, an alkaline aqueous solution or an acidic aqueous solution.

As a specific example of the hot water heating treatment condition, for example, the first step is to immerse in hot water at 65 to 90 캜 for 5 to 300 seconds, and then as the second step for 100 to 600 seconds in hot water at 85 to 100 캜 desirable. In order to increase the dissolution efficiency, nip treatment with a roll, high-pressure water treatment, ultrasonic treatment, shower treatment, stirring treatment, kneading treatment and the like may be carried out if necessary.

In this step, when the water-soluble thermoplastic resin is dissolved from the sea-island conjugate fiber to form the superfine fiber, the superfine fiber shrinks greatly. This contraction causes the fiber density to be dense, so that a high density fiber entangled body is obtained.

(6) Polymer elastomer filling process

Next, a process of filling the superfine fiber bundle formed of the superfine fiber with the polymer elastic body to confine the superfine fiber bundle together with the superfine fiber bundle, and further bonding the superfine fiber bundles together will be described.

In the microfine fiber formation step (5), the water-soluble thermoplastic resin is removed by forming microfine fibers on the sea-island composite fiber to form pores inside microfine fiber bundles. In this step, by appropriately filling the voids with a polymeric elastomer, the microfine fibers are concentrated and the microfine fiber bundles are bundled together, and the microfine fiber bundles are stuck together to reduce the porosity of the polishing pad to, for example, 50% or less It is possible to do. In addition, by filling the polymeric elastomer sufficiently, the porosity can be lowered, and the polishing pad can have a dense structure. In addition, when the microfine fibers form microfine fiber bundles, the microfine fibers tend to be more concentrated, and the microfine fiber bundles are liable to be more constrained because the aqueous liquid of the polymer elastic body is easily impregnated by the capillary phenomenon.

The aqueous liquid of the polymeric elastomer used in the present step may be the same as the aqueous liquid of the polymeric elastomer described in the fiber bundle binding step (4).

The same method as that used in the fiber bundle binding step (4) can be applied to the method of filling the polymeric elastomer into the microfine fiber bundles formed of microfine fibers in the present step. The desired void ratio can be adjusted by properly combining the fiber binding step (4) and the polymeric elastomer filling step (6). In this manner, a polishing pad is formed.

[Finishing of polishing pad]

The obtained polishing pad may be subjected to a post-treatment such as a forming treatment, a planarizing treatment, a bristling treatment, a lamination treatment, a surface treatment, and a cleaning treatment, if necessary.

The above-described forming process and planarizing process are processes in which the obtained polishing pad is hot-pressed by grinding to a predetermined thickness or is cut into a predetermined outer shape. As the polishing pad, it is preferable that the polishing pad has a thickness of about 0.5 to 3 mm.

The brushed treatment is a treatment for imparting mechanical frictional force or polishing force to the surface of the polishing pad by sandpaper, cloth, diamond or the like to disperse the ultrafine fibers. By such brushed treatment, the fiber bundles existing in the surface layer of the polishing pad are fibrillated, and a large number of microfine fibers are formed on the surface.

The above-mentioned lamination treatment is a treatment for adjusting the rigidity by attaching the obtained polishing pad to a substrate to laminate them. For example, the global flatness of the surface to be polished (the flatness of the entire non-abrasive substrate) can be further improved by laminating the polishing pad with an elastic sheet having a low hardness. The bonding at the time of lamination may be a melt bonding or an adhesive bonding. Specific examples of the above-described substrate include, for example, an elastic sponge body made of polyurethane or the like; A nonwoven fabric impregnated with polyurethane (for example, a trade name: Suba400, manufactured by Nitta Haas Co., Ltd.); An elastic resin film composed of a rubber such as natural rubber, nitrile rubber, polybutadiene rubber or silicone rubber, or a thermoplastic elastomer such as polyester thermoplastic elastomer, polyamide thermoplastic elastomer or fluorine thermoplastic elastomer; Foam plastic; And a sheet-like base material such as a knitted fabric or a woven fabric.

The surface treatment is a treatment for forming grooves or holes on the surface of the polishing pad in the form of a lattice, a concentric circle, a spiral or the like in order to adjust the retention and dischargeability of the abrasive slurry.

The cleaning process is a process in which impurities such as particles and metal ions attached to the obtained polishing pad are cleaned with cold water or hot water or an aqueous solution or a solvent containing an additive having a cleaning action such as a surfactant to be.

The polishing pad of the present embodiment can be applied to various types of semiconductor devices such as a silicon wafer, a compound semiconductor wafer, a semiconductor wafer, a semiconductor device, a liquid crystal member, an optical element, a quartz crystal substrate, an electronic circuit substrate, Micro-electro-mechanical systems) substrates and the like. The polishing pad of the present embodiment is particularly excellent in polishing a bare silicon wafer by setting the porosity of the polishing pad to 50% or more.

Specific examples of the semiconductor wafer and the semiconductor device include insulating films such as silicon, silicon oxide, silicon fluoride, and organic polymers; A wiring material metal film such as copper, aluminum, or tungsten; A substrate having a barrier metal film such as tantalum, titanium, tantalum nitride, or titanium nitride on its surface.

In polishing, it is used for any polishing such as primary polishing, secondary polishing (controlled polishing), finish polishing, mirror polishing, and the like. The polishing portion may be any of a surface, a back surface, and a cross section of the substrate.

Example

Hereinafter, the present invention will be described in detail with reference to examples. Further, the present invention is not limited by the embodiments.

[Example 1]

A water-soluble thermoplastic polyvinyl alcohol-based resin (hereinafter referred to as PVA-based resin) and an isophthalic acid-modified polyethylene terephthalate having a degree of modification of 6 mol% (absorptivity of 1 mass% (Hereinafter referred to as modified PET) at a ratio of 20: 80 (mass ratio) was discharged from the molten composite spinneret to form a sea-island complex fiber. In addition, the molten composite spinneret had a frequency of 50 degrees / fiber and a spinning temperature of 260 deg. Then, the ejector-pressure was adjusted to a spinning speed of 4000 m / min, and long fibers having an average fineness of 2.0 dtex were collected on a net to obtain a spunbond sheet (long fiber web) having a weight per unit area of 40 g / m 2.

Twelve sheets of the obtained spunbond sheet were cross-laminated to prepare an overlapped web having a total unit area of 480 g / m < 2 >. Then, the obtained overlapping web was sprayed with an anti-tack agent. Subsequently, the overlapped web was needle punched at 1,800 punch / cm < 2 > using needle needle having one barb number and needle number 42 and needle needle having six barbs and needle number 42 to obtain a web interlocked sheet. The weight per unit area of the resulting web entangled sheet was 750 g / m < 2 >. The area shrinkage ratio by the needle punching treatment was 35%.

Next, the obtained web of entangled sheet was steam-treated at 70 캜 and 90% RH for 90 seconds. The area shrinkage rate at this time was 40%. After drying in an oven at 140 deg. C, the web was subjected to hot pressing at 140 deg. C to obtain a web interlaced sheet having a weight per unit area of 1250 g / m2, an apparent density of 0.65 g / cm3, and a thickness of 1.9 mm. At this time, the thickness of the web offset sheet after hot pressing was 0.80 times the thickness of the hot press.

Next, a hot-pressed web offset sheet was impregnated with an aqueous dispersion of polyurethane elastomer A (solid concentration 20% by mass) as the first polyurethane elastomer. The polyurethane elastomer A is obtained by mixing an amorphous polycarbonate-based polyol (a copolymerized polyol comprising 3-methyl-1,5-pentylene carbonate and hexamethylene carbonate) with a polyalkylene glycol having 2 to 3 carbon atoms in an amount of 99.7: 0.3 (Hydroxymethyl) propionic acid) in an amount of 1.5 wt% is used as a soft component in an amount of 55 wt%, and a hard component Is an amorphous polycarbonate-based, non-sulfur-modified polyurethane resin obtained by polymerizing 4,4'-dicyclohexylmethane diisocyanate and a mono-chain polyamine and a mono-chain polyol. The polyurethane elastomer A had an absorption rate of 3 mass%, a storage elastic modulus at 23 占 폚 of 300 MPa, a storage elastic modulus at 50 占 폚 of 150 MPa, a glass transition temperature of -20 占 폚 and an average particle diameter of the aqueous dispersion of 0.03 占 퐉 . At this time, the amount of the solid content adhered to the aqueous dispersion was 10% with respect to the mass of the web misaligned sheet. Then, the web offset sheet impregnated with the aqueous dispersion was subjected to dry coagulation treatment at 90 占 폚 and 50% RH atmosphere, followed by drying treatment at 140 占 폚. Then, it was hot-pressed at 140 占 폚 to obtain a sheet having a weight per unit area of 1370 g / m2, an apparent density of 0.76 g / cm3, and a thickness of 1.8 mm.

Next, the PVA resin was dissolved and removed by immersing the web entangled sheet filled with the polyurethane elastomer A in nip treatment and high-pressure water flow treatment at 95 DEG C for 10 minutes while the PVA resin was dissolved, and then dried to obtain an ultrafine fiber having an average fineness of 0.05 dtex, a weight per unit area of 1220 g / m 2, an apparent density of 0.66 g / cm 3, and a thickness of 1.85 mm.

Then, the composite was impregnated with an aqueous dispersion of polyurethane elastomer B (solid concentration 30% by mass) as the second polyurethane elastomer. The polyurethane elastomer B was prepared by mixing an unmodified polycarbonate-based polyol (a copolymerized polyol comprising hexamethylene carbonate and pentamethylene carbonate) with a polyalkylene glycol having 2 to 3 carbon atoms in a ratio of 99.9: 0.1 (molar ratio) 50% by mass of a soft component containing a carboxyl group-containing monomer (2,2-bis (hydroxymethyl) propionic acid) in an amount of 1.5% by mass was used. To this was added 4,4'-dicyclohexylmethane diisocyanate Is a polyurethane resin having a crosslinked structure formed by adding 5 parts by mass of a carbodiimide-based crosslinking agent to 100 parts by mass of a polycarbonate-based, non-sulfur-modified polyurethane resin obtained by polymerization of an amine and a single- The absorption rate of the polyurethane elastomer B was 2 mass%, the storage elastic modulus at 23 占 폚 was 450 MPa, the storage elastic modulus at 50 占 폚 was 300 MPa, the glass transition temperature was -25 占 폚, and the average particle diameter of the aqueous dispersion was 0.05 占 퐉 . At this time, the amount of the solid content adhered to the aqueous dispersion was 15 mass% with respect to the mass of the composite. Next, the composite impregnated with the aqueous dispersion was coagulated at 90 DEG C under a 50% RH atmosphere, and further dried at 140 DEG C. [ Then, it was hot-pressed at 140 DEG C to obtain a polishing pad precursor. The obtained polishing pad precursor had a weight per unit area of 1390 g / m 2, an apparent density of 0.80 g / cm 3, and a thickness of 1.75 mm.

The obtained polishing pad precursor was obtained by collecting all the 50 microfine fibers constituting the microfine fiber bundle, and the polymer elastic body was present in the microfine fiber bundle and restrained the microfine fiber bundle.

The obtained polishing pad precursor was subjected to a grinding process for surface planarization to obtain a planarized pad having a weight per unit area of 1120 g / m 2, an apparent density of 0.80 g / cm 3, and a thickness of 1.4 mm. Further, a circle-shaped polishing pad was obtained by cutting into a circular shape having a diameter of 51 cm and forming grooves having a width of 2.0 mm and a depth of 1.0 mm on the surface in lattice form at intervals of 15.0 mm. The mass ratio of the fiber scatters to the polyurethane elastomer was 76/24, and the ratio of the polymeric elastomer A to the polymeric elastomer B was 40/60. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 1.

[Example 2]

The steps up to the production of the web-engaged sheet were carried out in the same manner as in Example 1. Next, the heat-pressed web entangled sheet without impregnating the polyurethane elastomer A was immersed in hot water at 95 캜 for 10 minutes to dissolve and remove the PVA resin to obtain a fiber entangled body composed of the fiber bundles of the ultrafine fibers. Then, the resulting fabric block was impregnated with an aqueous dispersion of polyurethane elastomer B (solid content concentration: 40% by mass). At this time, the solid content adhered amount of the aqueous dispersion was 20 mass% with respect to the mass of the fiber entangled body. Next, the fiber impregnated body impregnated with the aqueous dispersion was coagulated at 90 DEG C under a 50% RH atmosphere. Then, a polishing pad precursor was obtained by drying at 140 占 폚 and then hot pressing at 140 占 폚. Then, the obtained polishing pad precursor was subjected to post-treatment in the same manner as in Example 1 to give a weight per unit area of 1080 g / A planarized pad having a density of 0.77 g / cm 3 and a thickness of 1.4 mm was obtained and grooved to obtain a circular polishing pad. The polishing pad thus obtained had all 50 microfine fibers constituting the microfine fiber bundle focused, The polymeric elastomer was present in the bundle of microfine fibers and constrained microfine fiber bundles. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 1.

[Example 3]

A polishing pad was obtained in the same manner as in Example 1 except that the hot press treatment was not performed before impregnating the polyurethane elastomer A and after impregnation and drying.

The obtained polishing pad precursor had a weight per unit area of 1360 g / m 2, an apparent density of 0.62 g / cm 3, a thickness of 2.2 mm, and a mass ratio of the fibrous entangled body and the polyurethane elastomer was 70/30. The obtained polishing pad precursor was obtained by collecting all the 50 microfine fibers constituting the microfine fiber bundle, and the polymer elastic body was present in the microfine fiber bundle and restrained the microfine fiber bundle. The polishing pad obtained by performing planarization and grooving in the same manner as in Example 1 was evaluated by an evaluation method described later. The results are shown in Table 1.

[Example 4]

As a first polyurethane elastomer, a polyether-based polyalkylene glycol and a polycarbonate-based polyol were mixed in a ratio of 88:12 (molar ratio) instead of the polyurethane elastomer A, and a monomer containing a carboxyl group (2,2-bis (hydroxymethyl) Propionic acid) in an amount of 1.2 wt% as a soft component was used as a soft component, and a polycarbonate-based, non-sulfur-modified polyurethane obtained by polymerizing isophorone diisocyanate and a mono-chain polyamine and a mono- (Elastic modulus: 4%, storage modulus at 23 占 폚 of 250 MPa, storage elastic modulus at 50 占 폚 of 100 MPa, glass transition temperature: -30 占 폚, average particle diameter of aqueous dispersion: 0.03 占 퐉), and as the second polyurethane elastomer Instead of the polyurethane elastomer B, the polyol component of the polyurethane elastomer B was increased by 10 mass%, the polyol component was adjusted to 60 mass% with respect to the polyurethane elastomer The obtained polyurethane elastomer D (absorption rate 4%, storage elastic modulus at 23 占 폚 of 300 MPa, storage elastic modulus at 50 占 폚 of 125 MPa, glass transition temperature of -30 占 폚, average particle diameter of aqueous dispersion: 0.05 占 퐉) A polishing pad was prepared in the same manner as in Example 1. The obtained polishing pad was such that all 50 of the microfine fibers constituting the microfine fiber bundle were concentrated, and the polymer elastic body was present in the microfine fiber bundle and restrained the microfine fiber bundle. Then, the obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 1.

[Example 5]

A polishing pad was obtained in the same manner as in Example 1 except that the PVA resin and modified PET were melt-spun by discharging the PVA resin and modified PET at a ratio of 20:80 (mass ratio) from a nipple of 9 degrees / fiber. The average fineness of the microfine fibers was 0.28 dtex. Further, in the obtained polishing pad, all of the ultrafine fibers constituting the ultrafine fiber bundle were bundled together, and the elastic polymer body was present inside the ultrafine fiber bundle, so that the bundle of ultrafine fibers was restrained. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 1.

[Example 6]

The polishing performance of the polishing pad was evaluated in the same manner as in Example 1 except that the polishing pad obtained in Example 1 was used and the polishing conditions in evaluation of the polishing performance of the polishing pad described later were changed as follows. The polishing conditions are as follows.

(1) A silicon wafer having an oxide film was changed to a bare silicon wafer, and a slurry used for polishing was changed to Glanzox 1103 manufactured by Fuji Manufacturing Co., Ltd.

(2) The slurry used in the polishing was changed to a polishing slurry GPL-C1010 manufactured by Showa Denko KK and the slurry flow rate was changed to 200 ml.

(3) a tungsten wafer, and the slurry used for polishing was changed to Cavot Manufacturing W-2000 (34 g of hydrogen peroxide was added to 1030 g of slurry).

(4) GaAs wafers, the slurry used for polishing was changed to INSEC-FP manufactured by Fujimi, and the polishing pressure was changed to 20 ㎪.

The results are shown in Table 3.

[Example 7]

A polyurethane elastomer A was impregnated in a heat-pressed web interlaid sheet (weight per unit area of 1280 g / m 2, apparent density of 0.56 g / cm 3, thickness of 2.3 mm) to perform dry coagulation, A sheet having a weight per unit area of 1340 g / m 2, an apparent density of 0.69 g / cm 3, and a thickness of 1.95 mm was obtained without performing a heating press.

Next, the PVA resin was dissolved and removed by immersing the web entangled sheet filled with the polyurethane elastomer A in nip treatment and high-pressure water flow treatment at 95 DEG C for 10 minutes while the PVA resin was dissolved, and then dried to obtain an ultrafine fiber having an average fineness of 0.05 dtex, a weight per unit area of 1050 g / m 2, an apparent density of 0.57 g / cm 3, and a thickness of 1.85 mm.

The composite was impregnated with a polyurethane elastomer B as a second polyurethane elastomer, coagulated and dried, and a hot press was not carried out to obtain a polishing pad precursor. The obtained polishing pad precursor had a weight per unit area of 1170 g / An apparent density of 0.60 g / cm 3, and a thickness of 1.95 mm.

The obtained polishing pad precursor was ground for surface planarization to obtain a planarized pad having a weight per unit area of 1000 g / m 2, an apparent density of 0.57 g / cm 3, and a thickness of 1.75 mm. A circle-shaped polishing pad was obtained by cutting a circular shape having a diameter of 51 cm and forming grooves having a width of 2.0 mm and a depth of 1.0 mm on the surface at intervals of 15.0 mm in a lattice form. The polishing pad of a fibrous block and the polyurethane elastic body Mass ratio was 76/24, and the ratio of the polymeric elastomer A and the polymeric elastomer B was 40/60. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 1.

[Example 8]

Except that the polishing pad obtained in Example 7 was used and the polishing conditions in evaluation of the polishing performance of a polishing pad to be described later were changed as in (1) to (3) of Example 6, Polishing performance was evaluated.

The results are shown in Table 4.

[Comparative Example 1]

Ny6 was melt-spun by melt spinning Ny long fibers having an average fineness of 2 dtex, and the obtained long fibers were collected on a net to obtain a spunbond sheet (long-fiber web) having a weight per unit area of 30 g / m2.

An overlapped web was produced from the obtained spunbond sheet in the same manner as in Example 2. [ Then, the obtained overlapped web was subjected to needle punching and entanglement in the same manner as in Example 1 to obtain a web entangled sheet. The weight per unit area of the web entangled sheet thus obtained was 800 g / m 2. Next, a web entangled sheet having an apparent density of 0.42 g / cm3 and a thickness of 1.9 mm was obtained by hot pressing at 140 占 폚.

Next, a hot-pressed web offset sheet was impregnated with an aqueous dispersion of polyurethane elastomer B (solid concentration 30% by mass). At this time, the solid content adhered amount of the aqueous dispersion was 20 mass% with respect to the mass of the web misalignment sheet. Then, the web-entangled sheet impregnated with the aqueous dispersion was coagulated at 90 ° C and 90% RH atmosphere, dried at 140 ° C, and hot pressed at 140 ° C to obtain 920 g / An abrasive pad precursor having an apparent density of 0.54 g / m < 2 > and a thickness of 1.7 mm was obtained. Then, the surface and back surface were flattened by baffing treatment to obtain a polishing pad. The obtained polishing pad was evaluated by the following evaluation method. The results are shown in Table 2.

[Comparative Example 2]

As the polymeric elastomer, an aqueous dispersion of polyurethane elastomer E (solid content concentration 20% by mass) was impregnated instead of using the aqueous dispersion of polyurethane elastomer A to form a polyurethane elastomer. The polyurethane elastomer E was obtained by mixing polyol (60 mass% with respect to the polyurethane elastomer) in which polyethylene glycol / polytetramethylene glycol was mixed at 15/85, isophorone diisocyanate as a hard component and a short chain polyol Is a non-sulfur-modified polyurethane resin. The polyurethane elastomer E had an absorption rate of 12 mass%, a storage elastic modulus at 23 占 폚 of 200 MPa, a storage elastic modulus at 50 占 폚 of 80 MPa, a glass transition temperature of -48 占 폚 and an average particle diameter of the aqueous dispersion of 0.4 占 퐉 . A polishing pad was produced in the same manner as in Example 2 except for the above. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 2.

[Comparative Example 3]

A polyurethane elastic body F obtained by increasing the polyol component of the polyurethane elastomer B to 65 mass% (absorption rate 8%, storage elastic modulus at 23 캜 of 80 MPa, storage elastic modulus at 50 캜 of 30 MPa, glass transition temperature of -32 캜, And the average particle diameter of the aqueous dispersion was 0.02 占 퐉) was used as a polishing pad. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 2.

[Comparative Example 4]

The polyol component of the polyurethane elastomer B is a hexamethylene carbonate diol, and 30% by mass of a soft (polyol) component is used, and 4,4'-dicyclohexylmethane diisocyanate and a mono-chain amine A polyurethane elastic body G obtained by polymerizing diol (absorption rate 1%, storage elastic modulus at 23 캜 of 1000 ㎫, storage elastic modulus at 50 캜 of 200 ㎫, glass transition temperature of 0 캜, and average particle diameter of aqueous dispersion: 0.08 탆) A polishing pad was produced in the same manner as in Example 2 except for the above. The obtained polishing pad was evaluated by an evaluation method to be described later. The results are shown in Table 2.

The obtained polishing pad was evaluated by the following evaluation method.

 [Assessment Methods]

(1) Determination of average fineness of microfine fibers and concentration state of microfine fibers in the fiber bundles

The obtained polishing pad was cut in the thickness direction using a cutter blade to form a cut surface in the thickness direction. Then, the obtained cut surface was dyed with osmium oxide. Then, the cut surface was observed with a scanning electron microscope (SEM) at 500 to 1000 times, and the image was taken. Then, the sectional area of the ultrafine fibers existing on the cut surface was obtained from the obtained image. The average cross-sectional area of randomly selected 100 cross-sectional areas was taken as an average cross-sectional area, and the density was calculated from the density of the resin forming the fibers. In addition, a case in which not only superfine fibers constituting the outer periphery of the fiber bundle but also the inside superfine fibers are adhered and integrated by the polymer elastic body is focused is referred to as " focusing ", and a polymer elastic body And the state in which the microfine fibers are almost not adhered to each other and is not concentrated is determined as " no ".

(2) The storage elastic modulus of the elastomeric polymer at 23 캜 and 50 캜

A polymeric elastomer constituting the polishing pad was produced as a film sample having a length of 4 cm x width of 0.5 cm x thickness of 400 m 占 100 占 퐉. After measuring the sample thickness in micrometers, the sample was measured at 23 DEG C and 50 DEG C under the conditions of a frequency of 11 Hz and a temperature raising rate of 3 DEG C / min using a dynamic viscoelasticity measuring apparatus (DVE Rheospectra, Lt; 0 > C, the storage elastic modulus was calculated. In the case of using two kinds of polymeric elastomers, samples were separately prepared and measured, and the sum of the mass ratios was taken as the storage elastic modulus of the polymeric elastomer.

(3) Glass transition temperature of polymer elastomer

A polymer elastic body constituting the polishing pad was produced as a film having a length of 4 cm x width of 0.5 cm x thickness of 400 m 占 100 占 퐉. The dynamic viscoelasticity was measured at a frequency of 11 Hz and a heating rate of 3 DEG C / min using a dynamic viscoelasticity measuring device (DVE Rheospectra, manufactured by Rheology Co., Ltd.) after measuring the sample thickness in micrometers , And the main dispersion peak temperature of the loss elastic modulus was defined as the glass transition temperature. In the case of using two kinds of polymeric elastomers, samples were separately prepared and measured. The sum of the mass ratios was determined as the glass transition temperature of the polymeric elastomer.

(4) Absorption rate when the polymer elastomer is absorbed and saturated at 50 캜

A film having a thickness of 200 占 퐉 obtained by drying the polymeric elastomer at 50 占 폚 was heat-treated at 130 占 폚 for 30 minutes and then allowed to stand under the conditions of 20 占 폚 and 65% RH for 3 days as a dry sample, The sample was soaked for two days. Immediately after the film was taken out from the water at 50 ° C, extra water droplets on the outermost surface of the film were wiped with a JK Wiper 150-S (manufactured by Kureha Co., Ltd.) to obtain a water swollen sample. The mass of the dried sample and the swollen water sample was measured, and the water absorption ratio was determined according to the following equation.

Absorption rate (mass%) = [(mass of water swollen sample - mass of dried sample) / mass of dried sample] × 100

In the case of using two kinds of polymeric elastomers, samples were separately prepared and measured, and the sum of the weight ratios was taken as the absorption rate of the polymeric elastomer.

(5) Absorption rate when ultrafine fibers are absorbed and saturated at 50 占 폚 (absorptivity when absorbing and saturating the thermoplastic resin constituting the ultrafine fibers at 50 占 폚)

A film having a thickness of 200 占 퐉 obtained by hot pressing the thermoplastic resin constituting the superfine fiber at a temperature of the melting point + 20 to 100 占 폚 was heat-treated at 130 占 폚 for 30 minutes. Thereafter, the sample was allowed to stand under the conditions of 20 占 폚 and 65% RH for 3 days to obtain a dried sample. The dried sample was immersed in water at 50 占 폚 for 2 days, and then the surplus water droplet on the outermost surface of the film immediately after it was taken out from the water was wiped with JK Wiper 150-S (manufactured by Kureha Co., Ltd.) to obtain a water swollen sample. The mass of the dried sample and the swollen water sample was measured, and the water absorption ratio was determined according to the following equation.

Absorption rate (mass%) = [(mass of water swollen sample - mass of dried sample) / mass of dried sample] × 100

(6) Average particle diameter of aqueous polyurethane

Was measured by a dynamic light scattering method using "ELS-800" manufactured by Otsuka Chemical Co., Ltd. and analyzed by the Quluntur method (described in "Colloidal Chemistry, Vol. IV, When two kinds of polymeric elastomers were used, the samples were separately measured, and the sum of the mass ratios was taken as the value of the average particle diameter of the polymeric elastomer.

(7) The apparent density of the polishing pad and the porosity of the polishing pad (volume ratio of the void portion of the polishing pad)

The apparent density of the obtained polishing pad was measured according to JIS L1096. On the other hand, the theoretical density of the complex of the fibrous scraped body and the polymeric elastomeric body in the case where no void is present was calculated from the composition ratio of each component constituting the polishing pad and the density of each component. Then, the ratio of the apparent density to the theoretical density is regarded as the volume ratio of the filled portion of the polishing pad, and [1- (ratio of the apparent density to the theoretical density)] × 100 (% (The volume ratio of the void portion of the polishing pad). The density of each component used in Example 1 was denatured PET (1.38 g / cm3), polyurethane elastomer (1.05 g / cm3), and PVA resin (1.25 g / cm3).

(8) Evaluation of polishing performance of polishing pad

After adhering an adhesive tape to the back surface of the circular shape polishing pad, the adhesive tape was mounted on a CMP polishing apparatus ("PP0-60S" manufactured by Nomura Manufacturing Co., Ltd.). Using a diamond dresser (MEC200L manufactured by Mitsubishi Materials Corporation) having a number of # 200, distilled water was flown at a rate of 120 ml / min for 18 minutes at a pressure of 177 kPa and a dresser rotation speed of 110 rpm Conditioning (seasoning) was performed by grinding the surface of the polishing pad.

Next, under the conditions of a Pratten rotational speed of 50 rpm, a head rotational speed of 49 rpm, and a polishing pressure of 35 rpm, an abrasive slurry SS12 manufactured by Cabot Corp. was supplied at a rate of 120 ml / Having a diameter of 6 inches was polished for 100 seconds. Then, the thickness of any 49 points on the silicon wafer surface having the oxide film surface after polishing was measured, and the polishing rate (nm / minute) was obtained by dividing the polished thickness at each point by the polishing time. Then, the average value of the polishing rates at 49 points was taken as the polishing rate R, and the standard deviation (?) Thereof was determined.

Then, flatness was evaluated by the following formula. Also, the smaller the value of the flatness, the better the planarization performance.

Flatness (%) = (? / R) 占 100

Next, the polished polishing pad was allowed to stand in a wet state at 25 DEG C for 24 hours. Thereafter, after the seasoning, the polishing rate (R) and flatness after the same polishing again were obtained.

The seasoning and polishing were alternately repeated 300 times, and the polishing rate (R) and flatness at the 300th polishing were determined.

The scratch resistance was evaluated by measuring the number of scratches having a size of 0.16 mu m or more existing on the surface of a silicon wafer having an oxide film after each polishing, using a wafer surface inspection apparatus Surfscan SP1 (manufactured by KLA-Tencor Corporation).

(9) Evaluation of polishing performance of polishing pad in bare silicon wafer polishing

After attaching the adhesive tape to the back surface of the circular shape polishing pad, it was mounted on a CMP polishing apparatus ("PP0-60S" manufactured by Nomura Manufacturing Co., Ltd.). Using a diamond dresser (MEC200L manufactured by Mitsubishi Materials Corporation) having a number of # 200, distilled water was flown at a rate of 120 ml / min for 18 minutes at a pressure of 177 kPa and a dresser rotation speed of 110 rpm Conditioning (seasoning) was performed by grinding the surface of the polishing pad.

Next, while supplying Glanzox 1103 manufactured by Fujimi Inc., manufactured by Fujimi Inc., at a rate of 120 ml / min under conditions of a platen revolution speed of 50 revolutions per minute, a head revolution speed of 49 revolutions per minute, and a polishing pressure of 35 gallons, Inch silicon wafer was polished for 100 seconds. Then, the thickness of optional 49 points of the silicon wafer after polishing was measured, and the polishing rate (nm / minute) was obtained by dividing the polished thickness at each point by the polishing time. Then, the average value of the polishing rates at 49 points was taken as the polishing rate R, and the standard deviation (?) Thereof was determined.

Then, flatness was evaluated by the following formula. Also, the smaller the value of the flatness, the better the planarization performance.

Flatness (%) = (? / R) 占 100

Next, the polished polishing pad was allowed to stand in a wet state at 25 DEG C for 24 hours. Thereafter, after the seasoning, the polishing rate (R) and flatness after the same polishing again were obtained.

The seasoning and polishing were alternately repeated 300 times, and the polishing rate (R) and flatness at the 300th polishing were determined.

The results for Examples 1 to 5 and 7 are shown in Table 1, the results for Example 6 are shown in Table 3, the results for Example 8 are shown in Table 4, and the results for Comparative Examples 1 to 4 are shown in Table 2 Respectively.

As described above, one aspect of the present invention is a polishing pad comprising a microfine fiber embedding body formed of microfine fibers having an average fineness of 0.01 to 0.8 dtex and a polymeric elastomer, wherein the polymeric elastomer has a glass transition temperature of -10 Deg.] C or less, a storage elastic modulus at 23 [deg.] C and 50 [deg.] C of 90 to 900 MPa, and an absorption rate when absorption saturated at 50 deg. C is 0.2 to 5 mass%.

According to the above configuration, a polishing pad capable of stably grinding for a long period of time while suppressing the occurrence of scratches and achieving high flatness can be obtained.

It is preferable that the microfine fiber embroidery body is composed of microfine fiber bundles in which 5 to 70 microfine fibers are bundled, and the polymer elastomer is present in the microfine fiber bundle.

According to the above configuration, the superfine fiber is concentrated by the elastic polymer body and the bundle of microfine fibers is restrained, so that the rigidity of the polishing pad is enhanced, and the planarization performance, polishing uniformity and stability over time can be improved.

The microfine fibers are preferably formed of polyester fibers in that they can form dense and dense fiber entangled bodies.

It is preferable that the microfine fibers are formed of a thermoplastic resin having an absorption rate of 0.2 to 2% by mass when absorbed and saturated at 50 캜.

According to the above configuration, the polishing pad can be obtained in which degradation of the planarization performance over time is suppressed, and the polishing rate and polishing uniformity are not varied well.

The polymeric elastomer is a polyurethane resin obtained by using a polyol, a polyamine and a polyisocyanate. It is preferable that 60 to 100 mass% of the polyol is an amorphous polycarbonate-based diol.

According to the above structure, since the slurry used in polishing is highly resistant, the stability over time during polishing can be maintained satisfactorily.

The polymeric elastomer is preferably a polyurethane resin obtained by using an amorphous polycarbonate-based diol as a polyol and a carboxyl-containing diol as the polyol, and using an alicyclic diisocyanate as the polyisocyanate.

According to the above constitution, when the glass transition temperature of the polymeric elastomer is -10 占 폚 or less, the storage modulus at 23 占 폚 and 50 占 폚 is 90 to 900 MPa and the absorption rate when absorbed at 50 占 폚 is 0.2 to 5 mass% Can be easily adjusted.

The polymeric elastomer preferably has a storage elastic modulus at 23 ° C and a storage elastic modulus at 50 ° C (storage elastic modulus at 23 ° C / storage elastic modulus at 50 ° C) of 4 or less.

According to the above configuration, the change of the storage elastic modulus does not occur even when the temperature during polishing changes, so that the stability over time during polishing can be improved.

The polymeric elastomer is preferably an aqueous polyurethane having an average particle diameter of 0.01 to 0.2 μm from the viewpoint that good water resistance is obtained and binding force of the fiber bundle is improved.

When the ratio of the microfine fiber scaffold to the polymeric elastomer (microfine fiber entrapment / polymeric elastomer) is 55/45 to 95/5 by mass ratio, the polishing efficiency is improved and the pad wear during polishing is reduced .

It is also preferable that the volume ratio of the void portion in the polishing pad is 50% or more.

According to the above constitution, the polishing pad has favorable slurry lyophobicity, appropriate rigidity and cushioning property, and thus can be suitably used for bare silicon wafer polishing.

According to another aspect of the present invention, there is provided a microfine fiber bundle in which microfine fibers having an average fineness of 0.01 to 0.8 dtex are bundled, a glass transition temperature is -10 占 폚 or less, a storage elastic modulus at 23 占 폚 and 50 占 폚 is 90 To 900 MPa and a water absorption rate at 50 캜 of from 0.2 to 5% by mass.

According to such a manufacturing method, a polishing pad having high rigidity, high retainability of the abrasive slurry, and less scratches on the substrate to be polished can be obtained.

In the method for producing a polishing pad, the volume ratio of the void portion in the polishing pad is 50% or more, and the polymeric elastomeric material .

According to the above configuration, the porosity of the polishing pad can be set to 50% or more by adjusting the amount of the elastomeric polymer to be filled in the microfine fiber entangled body, so that it is suitable for bare silicon wafer polishing with appropriate rigidity, A polishing pad is obtained.

Industrial availability

The polishing pad according to the present invention can be applied to various types of devices such as various devices and various substrates on which planarization or mirror-polishing is performed, such as semiconductor substrates, semiconductor devices, compound semiconductor devices, compound semiconductor substrates, And can be used as a polishing pad for polishing LED products, silicon wafers, hard disk substrates, glass substrates, glass products, metal substrates, metal products, plastic substrates, plastic products, ceramic substrates and ceramic products.

Claims (12)

Wherein the polymeric elastomer has a glass transition temperature of -20 to -30 占 폚, a storage elastic modulus at 23 占 폚 and 50 占 폚, a storage modulus at 23 占 폚 and 50 占 폚, Is 90 to 900 MPa and the polymeric elastomer has a ratio of a storage elastic modulus at 23 ° C and a storage elastic modulus at 50 ° C (storage elastic modulus at 23 ° C / storage elastic modulus at 50 ° C) of 4 or less , And a water absorption rate at 50 占 폚 is 2 to 4% by mass. The method according to claim 1,
Wherein the microfine fiber embroidery body is composed of microfine fiber bundles in which 5 to 70 microfine fibers are bundled and the polymer elastomer is present inside the microfine fiber bundle. 3. The method according to claim 1 or 2,
Wherein the microfine fibers are formed of a polyester fiber. 3. The method according to claim 1 or 2,
Wherein the microfine fibers are formed of a thermoplastic resin having an absorption rate of 0.2 to 2% by mass when absorbed and saturated at 50 占 폚. 3. The method according to claim 1 or 2,
The polymeric elastomer is a polyurethane resin obtained by using a polyol, a polyamine and a polyisocyanate, wherein 60 to 100 mass% of the polyol is an amorphous polycarbonate-based diol. 6. The method of claim 5,
The polymeric elastomer is a polyurethane resin obtained by using an amorphous polycarbonate diol as a polyol and a carboxyl group-containing diol as the polyol, and using an alicyclic diisocyanate as the polyisocyanate. 3. The method according to claim 1 or 2,
Wherein the polymeric elastomer has a ratio of a storage elastic modulus at 23 占 폚 and a storage elastic modulus at 50 占 폚 (storage elastic modulus at 23 占 폚 / storage elastic modulus at 50 占 폚) of 3 or less. 3. The method according to claim 1 or 2,
Wherein the polymeric elastomer is an aqueous polyurethane having an average particle diameter of 0.01 to 0.2 mu m. 3. The method according to claim 1 or 2,
Wherein the ratio of the microfine fiber scaffold to the polymeric elastomer (microfine fiber entanglement / polymeric elastomer) is 55/45 to 95/5 by mass ratio. 3. The method according to claim 1 or 2,
Wherein the volume ratio of the void portion in the polishing pad is 50% or more. A glass transition temperature of -20 to -30 占 폚, a storage modulus at 23 占 폚 and 50 占 폚 of 90 to 900 MPa, and a glass transition temperature of 23 占 폚 to 50 占 폚 are provided inside microfine fiber bundles in which microfine fibers having an average fineness of 0.01 to 0.8 dtex are converged. (Storage elastic modulus at 23 占 폚 / storage elastic modulus at 50 占 폚) of the storage elastic modulus at 50 占 폚 and the storage elastic modulus at 50 占 폚 is 4 or less and the absorption rate when saturated at 50 占 폚 is 2 to 4 The method of manufacturing a polishing pad according to any one of claims 1 to 6, wherein the polymeric elastomer is filled in a mass%. 12. The method of claim 11,
Wherein the polymeric elastomer is filled in a microfine fiber embedding body composed of microfine fiber bundles in which the microfine fibers are bundled so that the volume ratio of void portions in the polishing pad is 50% or more.