KR20160013971A - Polishing agent composition, polishing agent composition for silicon wafer, and method for manufacturing silicon wafer product - Google Patents

Abstract

1. A polishing composition comprising silica particles, an alkaline substance, a water-soluble synthetic polymer and water, wherein the water-soluble synthetic polymer has a constituent unit (1), the constituent unit (1) Wherein the oxygen-containing group is an alcoholic hydroxyl group or a substituted or unsubstituted alkoxy group, and the carbonyl group is a carbonyl group constituting a keto group, an ester bond, or an amide bond, a silicon wafer Abrasive compositions, and methods of making silicon wafer products.

Description

TECHNICAL FIELD The present invention relates to an abrasive composition, an abrasive composition for a silicon wafer, and a method for producing a silicon wafer product.

The present invention relates to an abrasive composition, an abrasive composition for a silicon wafer, and a method for producing a silicon wafer product.

As an abrasive composition used for polishing a silicon wafer or the like, a slurry containing silica particles, an alkaline substance, a water-soluble polymer, water and, if necessary, an additive is used.

Examples of the water-soluble polymer used as the abrasive aid in the above-mentioned abrasive composition include substances obtained by solubilizing cellulose such as hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC ) Have been reported (Patent Document 1, Patent Document 2).

Examples of the water-soluble polymer other than the above-mentioned materials include water-soluble synthetic polymers. Examples of the water-soluble synthetic polymer include polyethylene oxide, polyacrylamide, and polyacrylic acid (Patent Document 2); Polyvinylpyrrolidone, poly N-vinylformamide (Patent Document 3); Block copolymers of ethylene oxide and propylene oxide (Patent Documents 4 and 5); Poly (N-acylalkyleneimine) (Patent Document 6); Or polyvinyl alcohol and its modified product (patent document 7), etc., can be used alone or in combination with other materials and as a polishing aid.

US Patent No. 3715842 Japanese Unexamined Patent Publication No. Hei 02-158684 Japanese Patent Application Laid-Open No. 2008-53415 Japanese Patent Application Laid-Open No. 10-245545 Japanese Patent Application Laid-Open No. 2005-85858 Japanese Patent Application Laid-Open No. 2010-099757 Japanese Laid-Open Patent Publication No. 2012-015462

However, the water-soluble polymer having solubilized cellulose inevitably remains insoluble components (free fiber) which are partially unreacted when the solubilization treatment is carried out. If the remaining insoluble components are mixed in the abrasive composition, surface defects tend to occur on the surface of the silicon wafer after polishing. Further, since the water-soluble polymer solubilized with cellulose is produced using natural pulp as a raw material, there is a large variation in the performance (solubility etc.) when the raw lots are different, and the surface quality (surface defect) of the silicon wafer product after polishing is not stable There is no problem.

On the other hand, conventionally used water-soluble synthetic polymers have high purity and problems caused by insoluble components are unlikely to occur. However, since they are low in hydrophilicity compared with water-soluble polymers obtained by solubilizing cellulose, maintenance of the polishing liquid And there is a problem that the deposit tends to remain on the wafer polishing surface after cleaning after polishing. Accordingly, development of a water-soluble synthetic polymer having a performance equal to or higher than that of a water-soluble polymer solubilized with cellulose has been demanded so as to more stably produce a polished product (such as a silicon wafer product) of higher quality.

It is an object of the present invention to provide a water-soluble synthetic polymer which is capable of stabilizing the surface quality of an object to be polished such as a silicon wafer after polishing and improving the wettability of the surface of the object to be polished, An abrasive composition capable of reducing the number of particles and LPD (Light Point Defect), an abrasive composition for a silicon wafer, and a method for producing a silicon wafer product using these abrasive compositions. LPD is a defect observed as a bright spot when a wafer surface is scanned by laser irradiation of a light scattering type fine particle counter.

That is, the present invention provides a polishing composition comprising silica particles, an alkaline substance, a water-soluble synthetic polymer, and water, wherein the water-soluble synthetic polymer has a constituent unit (1) And a carbonyl group, the oxygen-containing group is an alcoholic hydroxyl group or a substituted or unsubstituted alkoxy group, and the carbonyl group may be a keto group, a carbonyl group forming part of an ester bond, or a carbonyl (1). ≪ RTI ID = 0.0 > (1) < / RTI >

The present invention also provides an abrasive composition comprising silica particles, an alkaline substance, a water-soluble synthetic polymer, and water, wherein the water-soluble synthetic polymer is a reaction product obtained by reacting an epoxy compound with the water- (Sun 2).

Further, the present invention is an abrasive composition for a silicon wafer comprising the abrasive composition of the above-mentioned aspect 1 or 2 (aspect 3).

Further, the present invention is a method for manufacturing a silicon wafer product, which comprises a step of polishing a silicon wafer using the polishing compound composition of any one of the above-mentioned 1 to 3.

By using the water-soluble synthetic polymer of the present invention as a polishing aid, it is possible to constitute an abrasive composition having hydrophilicity equivalent to that obtained by using a conventional water-soluble polymer solubilized in cellulose. Such a water-soluble synthetic polymer is less prone to variation in quality than a water-soluble polymer solubilized with cellulose. Therefore, by using the water-soluble synthetic polymer of the present invention as a polishing assistant, it is possible to improve the wettability to the surface of the object to be polished, and to provide a silicon wafer which can stably supply silicon wafers having high quality surface characteristics (low remaining fine particles, low LPD) It becomes possible to provide an abrasive composition and a manufacturing method of a silicon wafer product using the same.

 1 is a schematic view showing a single-sided polishing apparatus.

An abrasive composition according to an embodiment of the present invention will be described.

An abrasive composition according to an embodiment of the present invention comprises silica particles (i), an alkaline substance (ii), a water-soluble synthetic polymer (iii), and water (iv). The abrasive composition according to the present embodiment may further include an additive (v).

In the present specification, " silica particle (i) " is a generic name of particles represented by the composition formula SiO ₂ and particles obtained by surface-treating the particles. Examples of the silica particles (i) include colloidal silica, fumed silica, and precipitated silica, and surface-modified silica obtained by subjecting the surface of the silica particles to boric acid treatment or aluminous acid treatment . Of these, colloidal silica and surface-modified silica thereof are more preferable from the viewpoint of improving surface characteristics of a silicon wafer. The average particle diameter of the silica particles (i) can be measured by a BET method and a dynamic light scattering method.

The particle size of the silica particles (i) is not limited. The particle diameter of the silica particles (i) can be selected according to properties required for the product after polishing. For example, when improvement of the surface properties after polishing is required, the primary particle diameter (which can be measured by the BET method) is 10 to 40 nm, or 10 to 20 nm, and the secondary particle diameter Method can be 20 to 80 nm, or 20 to 40 nm.

The production method of the silica particles (i) is not limited. As a method of synthesizing the silica particles (i), a hydrothermal synthesis method from water glass, a sol-gel method from an alkoxysilane or a condensate thereof, and a gas phase synthesis method from a silicon chloride are known. When the object to be polished is a silicon wafer, the silica particles (i) produced by the sol-gel method from alkoxysilane or a condensate thereof from the viewpoint of preventing the silicon wafer from being contaminated by impurities such as alkali metals and alkaline earth metals, .

The shape of the silica particles (i) is not particularly limited. Specific examples of the shape of the silica particles (i) include a sphere type, a cocoon type, a new cocoon type, and a type in which fine projections are formed. The cocoon-shaped and cocoon-shaped silica particles refer to silica particles characterized in that the ratio of the secondary particle diameter / primary particle diameter is from 1.5 to 2.5. Among the cocoon-like silica particles, the silica particles prepared by a method including a step of hydrolyzing a condensate of an alkoxysilane may be referred to as a cocoon-shaped silica particle in particular (Japanese Patent No. 4712556). In this specification, unless otherwise specified, such as "cocoon type (not including cocoon type)", the term "cocoon type" also includes a cocoon type. It is preferable to use a cantilever-type and a cantilever-type in order to improve both the polishing rate and the surface accuracy.

The content of the silica particles (i) is not limited. The content of the silica particles (i) is preferably 0.05 wt% or more and 0.5 wt% or less in the abrasive composition (slurry) used at the time of polishing.

The alkaline substance (ii) can generate hydroxide ions capable of chemically polishing the object to be polished, such as a silicon wafer, in water. It also has an action to help disperse the silica particles (i). From the viewpoint of more stably obtaining such action, the alkaline substance (ii) is preferably dissolved in the composition.

Examples of the alkaline substance (ii) include ammonia, an organic amine compound, tetramethylammonium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the organic amine compound include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethanolamine, diisopropylethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tris N, N ', N'-tetramethylethylenediamine, hexamethylenediamine, 1,4,7-triazacyclononane, 1,4,7-trimethyl-1,4,7 -Triazacyclononane, 1,4-diazabicyclooctane, piperazine, and piperidine. The alkaline substance (ii) may be composed of one kind of the above-mentioned substances, or may be composed of two or more kinds.

Of the alkaline substance (ii), ammonia, an organic amine compound and tetramethylammonium hydroxide are preferable in view of not containing an alkali metal ion, and ammonia is particularly preferable in view of having a suitable pKa.

The concentration of the alkaline substance (ii) depends on the pKa of the alkaline substance (ii) used and the content of the silica (i). The concentration of the alkaline substance (ii) is preferably such that the pH is 9.0 to 11.5, and the pH is 10.0 to 11.0, more preferably in a concentration of 40 times the polishing composition (slurry) used in polishing .

The water-soluble synthetic polymer (iii) contributes to polishing by adsorbing on the surface of the object to be polished such as a silicon wafer and forming a hydrophilic film.

In the present specification, the "water-soluble synthetic polymer" refers to a water-soluble polymer not derived from a natural product (such as cellulose). However, it is not contradicted that the water-soluble polymer derived from a natural substance obtained by solubilizing cellulose such as hydroxyethyl cellulose as the additive (v) in the range not hindering the effect of the present invention.

The abrasive composition according to the present embodiment has the constitutional unit (1) wherein the water-soluble synthetic polymer (iii) has an oxygen-containing group and a carbonyl group in the specific embodiment 1 thereof. Such an oxygen-containing group is an alcoholic hydroxyl group or a substituted or unsubstituted alkoxy group, and the carbonyl group is any one of a ketone group, a carbonyl group forming part of an ester bond, or a carbonyl group forming a part of an amide bond.

The unsubstituted alkoxy (-OAk) group includes, for example, an alkoxy group such as a methoxy group (-OCH ₃ ) and an ethoxy group (-OCH ₂ CH ₃ ). Here, " Ak " represents a linear or branched alkyl group. The carbon number of the alkyl group is not limited. For example, an alkyl group having 1 to 22 carbon atoms, 1 to 12, 1 to 6, or 1 to 4 carbon atoms.

The substituted alkoxy group (-OAk ') is a group in which at least one carbon atom of the alkoxy group is substituted. The substituent includes, for example, a hydroxyl group, an alkoxy group (which may be substituted or unsubstituted), and a halogen. Here, "Ak '" represents a straight-chain or branched alkyl group. The carbon number of the alkyl group is not limited. For example, an alkyl group having 1 to 22 carbon atoms, 1 to 12, 1 to 6, or 1 to 4 carbon atoms.

Examples of the substituted alkoxy group include a hydroxyalkoxy group such as a hydroxymethoxy group (-OCH ₂ OH) and a hydroxyethoxy group (-OCH ₂ CH ₂ OH). A plurality of substituted alkoxy _{groups, -OCH 2 CH (OH) CH} 2 OH, -OCH (CH 2 OH) CH 2 OH, -OCH 2 CH (CH 3) OH, and -OCH (CH ₃₎ CH ₂ OH For example. At least one of the hydroxyl groups contained in such a substituted alkoxy group may be substituted with a substituted alkoxy group (specific examples include a hydroxyl group substituted alkoxy group).

The monomer giving the constituent unit (1) is not particularly limited. An example of such a monomer is a monomer (?) Comprising a compound having an ethylenic unsaturated bond. Examples of the compound having an ethylenic unsaturated bond include (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, N-substituted (meth) acrylamide, acrylonitrile, vinyl ester, Allyl amines, allyl esters, allylamides, and styrene.

The monomer (?) May have both an oxygen-containing group and a carbonyl group, and may be a compound having no oxygen-containing group, a compound having no carbonyl group, or a compound having no functional group. For the monomer (a) having no oxygen-containing group, no carbonyl group, or none of these functional groups, necessary functional groups can be introduced after polymerization.

The monomer (?) May be a reaction product obtained by reacting a compound having an ethylenic unsaturated bond and a hydroxyl group with a cyclic ether compound, and having a substituted alkoxy group. In the present specification, the "cyclic ether compound" means a compound having a cyclic ether structure such as an epoxy group or an oxetane ring, and the structure of which can be ring-opened to react with the hydroxyl group of the compound. As a typical example of the cyclic ether compound, an epoxy compound which is a compound having an epoxy group can be mentioned. The epoxy group of the epoxy compound may be substituted. As such an epoxy compound, ethylene oxide, propylene oxide, and glycidol are preferable examples.

The structural unit (1) may contain at least one unit selected from the units (1A) to (1F) represented by the general formulas (1A) to (1F).

In the above formulas 1A to 1F, X is CH ₂ , NH, or an oxygen atom, preferably NH or an oxygen atom, more preferably NH. Each R ¹ independently represents a hydrogen atom or a methyl group. R ² each independently represents a hydrogen atom, a hydroxyl group, or a substituted or unsubstituted alkoxy group. m1 to m10 each independently represents an integer of 1 to 6, preferably an integer of 1 to 3; At least one of R < ² > in each unit is a substituent other than a hydrogen atom.

M1 R < ² > in the unit (1A) represented by the general formula (1A) may be different substituents. At least one of m1 R < ² > is a substituent other than a hydrogen atom. At least one of m1 R < ² > is preferably a hydroxyl group or substituted alkoxy group, more preferably two or more hydroxyl groups are present.

In the unit (1A) represented by the general formula (1A), m1 is an integer of 3 to 6, R ¹ is a methyl group, or X is an oxygen atom.

The (m2 + m3 + 1) R ² groups present in the unit (1B) represented by the general formula (1B) may be different substituent groups. at least one of (m2 + m3 + 1) R < ² > is a substituent other than a hydrogen atom. at least one of (m2 + m3 + 1) R < ² > is preferably a hydroxyl group or a substituted alkoxy group, more preferably two or more hydroxyl groups are present.

The (m4 + m5 + m6) R ² groups present in the unit (1C) represented by the general formula 1C may be different substituents. at least one of (m4 + m5 + m6) R < ² > is a substituent other than a hydrogen atom. at least one of (m4 + m5 + m6) R ² is preferably a hydroxyl group or a substituted alkoxy group, more preferably two or more hydroxyl groups are present.

The (m7 + m8) R ² groups present in the unit (1D) represented by the general formula 1D may be different substituent groups. at least one of (m7 + m8) R < ² > is a substituent other than a hydrogen atom. at least one of (m7 + m8) R ² is preferably a hydroxyl group or a substituted alkoxy group, more preferably two or more hydroxyl groups are present.

M9 R < ² > in the unit (1E) represented by the general formula 1E may be different substituents. At least one of m9 R < ² > is a substituent other than a hydrogen atom. At least one of m9 R < ² > is preferably a hydroxyl group or a substituted alkoxy group, more preferably two or more hydroxyl groups are present.

M10 R < ² > existing in the unit (1F) represented by the general formula 1F may be different substituents. At least one of m10 R < ² > is a substituent other than a hydrogen atom. At least one of m10 R < ² > is preferably a hydroxyl group or substituted alkoxy group, more preferably two or more hydroxyl groups are present.

From the viewpoint of enhancing the hydrophilicity of the water-soluble polymer (iii), each of the units (1A) to (1F) represented by the general formulas 1A to 1F preferably has at least one hydroxyl group, .

The unit (1A) is obtained, for example, by polymerizing the monomer (?). Examples of the monomer (?) Used herein include N- (hydroxymethyl) acrylamide, N- (2-hydroxyethyl) acrylamide, (2,3- dihydroxypropyl) (Hydroxymethyl) methacrylamide, N- (2-hydroxyethyl) methacrylamide, (2,3-dihydroxypropyl) methacrylamide, N- (hydroxymethyl) (2,3-dihydroxypropyl) acrylate, N- (hydroxymethyl) methacrylate, N- (2-hydroxyethyl) methacrylate, and (2,3 - dihydroxypropyl) methacrylate.

The unit (1B) is obtained, for example, by polymerizing the monomer (?). Examples of the monomer (?) To be used herein include N- [bis (hydroxymethyl) methyl] acrylamide and (2-hydroxy-1-methylethyl) acrylamide.

The unit (1C) is obtained, for example, by polymerizing the monomer (?). As the monomer (?) Used herein, there is, for example, N- [tris (hydroxymethyl) methyl] acrylamide.

The unit (1D) is obtained, for example, by polymerizing the monomer (?). Examples of the monomer (?) To be used herein include N, N-bis (hydroxymethyl) acrylamide and N, N-bis (hydroxyethyl) acrylamide.

The unit (1E) is obtained, for example, by polymerizing the monomer (?). Examples of the monomer (?) To be used herein include N-glycollylvinylamine, N-lactylvinylamine, and N- (3-hydroxypropionyl) vinylamine and pentahydroxyhexanoylvinylamine. Here, the pentahydroxyhexanoylvinylamine is obtained, for example, by reacting vinylamine with gluconolactone.

The unit (1F) is obtained, for example, by polymerizing the monomer (?). Examples of the monomer (?) To be used herein include N-glycollyl allylamine, N-lactylallylamine, N- (3-hydroxypropionyl) allylamine and pentahydroxyhexanoyl allylamine. Here, the pentahydroxyhexanoyl allylamine is obtained, for example, by reacting allylamine with glucololactone.

In addition to the above, units (1A) to (1F) may be synthesized by first polymerizing appropriate monomers and making them into polymers, and then reacting the polymer with an appropriate compound.

The unit (1A) to the unit (1C) can be obtained by, for example, reacting a poly (meth) acrylic acid or a poly (meth) acrylic acid ester with an alcohol having a suitable substituent or a primary amine.

The unit (1D) can be obtained, for example, by reacting a poly (meth) acrylic acid or a poly (meth) acrylic acid ester with a secondary amine having an appropriate substituent.

The unit (1E) can be obtained by reacting polyvinyl alcohol or polyvinylamine with a carboxylic acid, carboxylic anhydride, carboxylic acid chloride, or lactone having an appropriate substituent.

The unit (1F) can be obtained by reacting a polyallyl alcohol or a polyallylamine with a carboxylic acid having a suitable substituent, a carboxylic anhydride, a carboxylic acid chloride, or a lactone.

The water-soluble synthetic polymer (iii) may be a homopolymer or a copolymer. That is, when the structural unit (1) contains any one of the units (1A) to (1F), it may be a homopolymer composed of only the same unit, or a copolymer composed of two or more different units have. In the case of copolymers, two or more different units may be included in any proportion. And may contain a structural unit other than the structural unit (1).

The water-soluble synthetic polymer (iii) may further comprise a structural unit (2) represented by the following general formula (2).

In the formula 2, q is an integer of 1 to 6, preferably an integer of 1 to 3. X is CH ₂ , NH or an oxygen atom. Z ¹ , Z ² , Z ³ , and Z ⁴ are each independently a hydrogen atom or a methyl group. Y ^- is an anion. Examples of the anion include a chloride ion, a bromide ion, an iodide ion, a nitrate ion, an acetic acid ion, a sulfate ion, a phosphate ion, and a hydroxide ion. For the anion having a valence of more than 1, such as sulfate ion (SO ₄ ^2- ), Y ^- contained in the constitutional unit (2) is equivalent in terms of unit price conversion (in the case of sulfate ion, 1/2).

The cationic group in the formula 2 is a primary to quaternary amino group (ammonium group).

The method of obtaining the structural unit (2) is not limited. For example, the following structural unit (2) can be obtained by polymerizing the following compounds as monomers. Examples of N-substituted acrylamides include N- (aminomethyl) acrylamide, N- (aminoethyl) acrylamide, N- (aminopropyl) acrylamide, N- (monomethylaminoethyl) (Acrylamidoethyl) trimethylammonium salt, and (acrylamidopropyl) trimethylammonium salt can be cited as examples of the aminopropylmethylammonium salt of (meth) acrylamide, N- (dimethylaminoethyl) acrylamide, N- (dimethylaminopropyl) Alternatively, an appropriate compound (acrylic acid, methacrylic acid, acrylate, methacrylate, acrylamide, and methacrylamide, and derivatives thereof are exemplified) is taken as a monomer into the polymer by polymerization, To introduce a primary to quaternary amino group (ammonium group), thereby constructing the constituent unit (2).

Since the constituent unit 2 has a cationic group, when the object to be polished is a silicon wafer, the silicon wafer is negatively charged during polishing, so that the adsorption of the water-soluble polymer (iii) And it is expected that a protective film based on the water-soluble polymer (iii) is likely to be formed on the silicon wafer.

The abrasive composition according to the present embodiment is the abrasive composition according to the second aspect of the present invention wherein the water-soluble synthetic polymer (iii) is obtained by reacting any one of the water-soluble synthetic polymers (iii) of the above-mentioned aspect 1 with a cyclic ether compound such as an epoxy compound Reactants. Describing the epoxy compound as a specific example, ethylene oxide and glycidol have an effect of improving hydrophilicity, and propylene oxide has an effect of increasing hydrophobicity and enhancing adsorption to a wafer. In the case of the sun 2, glycidol is particularly preferable.

The terminal structure of the water-soluble synthetic polymer (iii) according to the present embodiment is not particularly limited. For the purpose of controlling the molecular weight, a known chain transfer agent may be used to constitute the terminal structure. From the viewpoint of introducing a hydroxyl group at the terminal, preferable examples of the chain transfer agent include isopropyl alcohol, glycerin, and thioglycerin.

As the constitutional unit of the water-soluble synthetic polymer (iii) according to the present embodiment, for the purpose of imparting various properties or adjusting hydrophilicity and hydrophobicity, other known constitutional units may be contained. For example, there are constitutional units having a structure obtained by polymerization of the following monomers (of course, other monomers may be polymerized and further reacted to result in the same constitutional unit): acrylamide, N-methyl Acrylamide, N-isopropylacrylamide, N-alkyl acrylamide, N, N-dimethylacrylamide, N, N-dialkyl acrylamide, acryloylmorpholine, N- (trimethoxysilylalkyl) acrylamide (Vinyl alcohol), vinyl amide (vinyl amine), N-alkanoyl vinyl amine, N-monoalkyl vinyl amine (meth) acrylate, , N, N-dialkyl vinylamine, allylamine, N-alkanoyl allylamine, N-monoalkyl allylamine, N, N-dialkyl allylamine, vinyl pyrrolidone, oxazoline, alkyl oxazoline, Imidazole, vinylpyridine (vinylpyridine Di-N-oxide), styrene, and hydroxystyrene.

The method of polymerizing monomers to give the constituent units contained in the water-soluble polymer (iii) such as the constituent unit (1) and the constituent unit (2) is not limited. Can be polymerized by a conventionally known method.

The molar fraction of the constituent unit (1) to the whole constituent units of the water-soluble synthetic polymer (iii) according to the present embodiment is not particularly limited. It is preferably at least 50 mol%, more preferably at least 70 mol%, and even more preferably at least 80 mol% from the viewpoint of hydrophilicity.

The molar fraction of the constituent unit (2) relative to the entire constituent units of the water-soluble synthetic polymer (iii) according to Sun 2 is not particularly limited. The molar fraction of the constituent unit (2) is preferably less than 50 mol%, more preferably 0.01 mol% or more and 10 mol% or less from the viewpoint of appropriately suppressing the aggregation of silica. When the aggregation of silica is to be more stably suppressed, the molar fraction of the constituent unit (2) can be set to 0.01 mol% or more and 5 mol% or less. When the object to be polished is a silicon wafer, the molar fraction of the constituent unit (2) can be set to 0.01 mol% or more and 2 mol% or less from the viewpoint of reducing the haze of the wafer after polishing.

The molecular weight of the water-soluble synthetic polymer (iii) according to the present embodiment is not limited. From the viewpoint of adsorbing on the surface of the object to be polished such as a silicon wafer and obtaining a protective film of appropriate strength, the weight average molecular weight (Mw) is preferably 1,000 or more. From the viewpoint of obtaining a stronger protective film, the weight average molecular weight (Mw) is more preferably 5,000 or more. In order to obtain a stronger protective film, the weight average molecular weight (Mw) is preferably 10,000 or more. On the other hand, if the weight average molecular weight (Mw) is too large, the aggregation of the silica may be promoted excessively, or the protective film may be hardly removed by water washing after polishing. Therefore, the water-soluble synthetic polymer (iii) according to the present embodiment preferably has a weight average molecular weight (Mw) of 5,000,000 or less. In addition, when the weight average molecular weight (Mw) is large, the protective film formed from the water-soluble synthetic polymer (iii) may have a structure having many voids. From the viewpoint of more stably reducing the possibility of forming such a protective film, 1,000,000 or less is preferable.

The concentration of the water-soluble synthetic polymer (iii) according to the present embodiment is preferably 10 ppm or more and 1000 ppm or less in the polishing composition (slurry) used at the time of polishing. Of these, more preferably 20 ppm or more and 750 ppm or less.

In the abrasive composition according to the present embodiment, the water (iv) has a function of dissolving or dispersing other contained components. In order to prevent the inhibition of the function of other components, it is preferable that the impurity contained in the water (iv) is small. Specifically, distilled water, ion-exchanged water, ultrapure water and the like are preferable. The content of water (iv) in the abrasive composition is a residual amount relative to the concentration or content of other components in the polishing composition.

The abrasive composition according to the present embodiment may further include an additive (v). For example, in order to adjust various properties of the slurry, to capture a metal ion, to assist in adsorption to an object to be polished (specifically, a silicon wafer is exemplified) of the water-soluble synthetic polymer (iii) , Additives may be added. Concretely, for example, at least one additive may be added from alcohols, chelates, and a nonionic surfactant. Examples of the alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin, polyethylene glycol, and polypropylene glycol. Examples of the chelates include ethylenediamine tetraacetic acid (EDTA), nitrilo triacetic acid (NTA), hydroxyethylenediamine tetraacetic acid, propanediamine tetraacetic acid, diethylene triamine oxoacetic acid, triethylenetetramine hexacetic acid, And metal salts such as ammonium salts, sodium salts, and potassium salts. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyalkylene alkyl ethers, polyoxyalkylenealkenyl ethers, alkylpolyglucosides, and polyether-modified silicones.

The method of producing the abrasive composition according to the present embodiment is not limited. Conventionally known methods can be used. For example, the abrasive composition according to the present embodiment is obtained by mixing silica particles (i), an alkaline substance (ii), a water-soluble synthetic polymer (iii), and water (iv).

A specific example 3 of the abrasive composition according to the present embodiment relates to an abrasive composition for a silicon wafer comprising the abrasive composition according to any one of the above-mentioned aspects 1 and 2.

The abrasive composition for a silicon wafer can be obtained by mixing silica particles (i), an alkaline substance (ii), a water-soluble synthetic polymer (iii), and water (iv). The obtained abrasive composition for a silicon wafer can be used, for example, for final polishing of a silicon wafer in a semiconductor device manufacturing process.

A specific aspect 4 of the abrasive composition according to the present embodiment relates to a method of manufacturing a silicon wafer product including a step of abrading a silicon wafer using the abrasive composition according to any one of the above-mentioned aspects 1 and 2. As used herein, the term "silicon wafer product" refers to a product obtained by polishing a silicon wafer using the abrasive composition according to any one of the above-mentioned aspects 1 and 2. Such a step can be introduced as a polishing step of a silicon wafer, and it is particularly preferable to introduce it as a final polishing step of a silicon wafer.

The abbreviations used in the present specification are as follows.

HEAA: N- (2-hydroxyethyl) acrylamide

TMAPAA: (3-acrylamidopropyl) trimethylammonium chloride

DHPMA: A mixture of (2,3-dihydroxypropyl) methacrylate and bis (hydroxymethyl) methyl methacrylate (about 75 mol%: about 25 mol%)

THMMAA: N- [tris (hydroxymethyl) methyl] acrylamide

HPAA: N- (3-hydroxypropyl) acrylamide

DHPAA: N- (2,3-dihydroxypropyl) acrylamide

HEMAA: N- (2-hydroxyethyl) methacrylamide

DHPMAA: N- (2,3-dihydroxypropyl) methacrylamide

HEAA-GO _0.25 : N- (2-hydroxyethyl) acrylamide glycidol adduct

PAA: poly (acrylamide)

PHEOVE: poly (hydroxyethyloxyethyl vinyl ether)

PVA: polyvinyl alcohol

PVP: poly (vinylpyrrolidone)

PPEI: poly (N-propionylethyleneimine)

The embodiments described above are described for the purpose of facilitating understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment has the purpose of including all design changes or equivalents belonging to the technical scope of the present invention.

Example

Hereinafter, the present invention will be described concretely with reference to Examples, but the present invention is not limited to the following Examples.

Examples 1 to 8, Reference Example 1, and Comparative Examples 1 to 5

<Preparation of monomers>

DHPMA was synthesized from the glycidyl methacrylate produced by Aldrich Co. by the method described in Shaw et al., Polymer 47, 8247-8252, 2006. According to the literature, the product is a mixture of (2,3-dihydroxypropyl) methacrylate and bis (hydroxymethyl) methyl methacrylate (about 75 mol%: about 25 mol%). When the product was confirmed by GPC measurement, two peaks were observed at an area ratio of 75:25.

The other monomers are available as follows.

HEAA: Tokyo Hwaseong Co.

TMAPAA: Tokyo Harmony Company

THMMAA: Aldrich

AA: Tokyo Hwaseong Company

&Lt; Synthesis of water-soluble synthetic polymer &

The water-soluble synthetic polymers of Examples 1 to 8 and Comparative Example 1 were synthesized by the following methods.

1.0 mol of the monomer (in the case of the copolymer, 1.0 mol of the total amount of the monomer materials) was added to an ammonium persulfate solution (1.6 g (7.0 mmol) of ammonium persulfate and 1000 g of pure water) maintained at 70 DEG C under a nitrogen stream. And pure water (960 g) was added dropwise over about 2 hours. After completion of the dropwise addition, the mixture was stirred at 70 DEG C for 1 hour and then cooled to room temperature. Then, to remove unreacted monomers, the reaction solution was added dropwise to acetone of 5 times. The resulting precipitate was taken out by decantation, washed with acetone for 1 time, and then vacuum-dried.

Examples 2 and 3 are copolymers composed of HEAA and TMAPAA, Examples 5 and 6 are copolymers composed of HEAA and DHPMA, and Example 8 are copolymers composed of HEAA and THMAA. The input ratio (molar ratio) of each monomer is shown in Table 1.

The HEC in Reference Example 1 was obtained from Daiseppin Chem, and the PEG was obtained from Wako Pure Chemical Industries, respectively.

The PVA of Comparative Example 2 was obtained from Wako Pure Chemical Industries, and the PHEOEVE of Comparative Example 3 was obtained from Maruzen Petrochemical Co., respectively.

The PVP of Comparative Example 4 and the PPEI of Comparative Example 5 were obtained from Aldrich.

Example 9

<Synthesis of polyHPAA>

0.020 g of APS was added to a mixture of 2.15 g of methyl acrylate (MA) and 8.58 g of methanol, followed by polymerization at 65 占 폚 for 10 hours under nitrogen. Thereafter, the reaction solution was cooled at room temperature, and the resulting precipitate was withdrawn by decantation to obtain a polyacrylic acid methyl solid (conversion rate: 97%). Methanol 8.58 g was further added to the obtained methyl polyacrylate solid, heated at 65 占 폚 for 10 minutes, cooled at room temperature, and the supernatant was removed to remove unreacted monomers.

5.63 g of 3-aminopropanol and 0.082 g of a 28% NaOMe methanol solution were added to the obtained methyl polyacrylate and amidation reaction was carried out at 100 占 폚 for 20 hours. After completion of the reaction, the reaction solution was added dropwise to 25 g of acetone after adding 3.3 g of methanol. The resulting solid was separated from the supernatant by decantation and further treated with 15 g of acetone, followed by vacuum drying at 40 DEG C for 1 hour. After drying, the solution was dissolved in 30 g of pure water, followed by filtration through 3 탆 of a filter. A few g of the filtrate was sampled, and the polymer concentration was quantitatively determined by the drying method. An appropriate amount of purified water was finally added to the polyHPAA 5% aqueous solution (yield: 80%).

Example 10

<Synthesis of polyDHPAA>

From the synthesis of polyHPAA, a 5% aqueous solution of polyDHPAA (yield 75%) was obtained in the same manner except that 3-amino propanol was changed to 6.83 g of 3-amino-1,2-propanediol.

Example 11

<Preparation of monomers>

0.984 g of a 28% NaOMe methanol solution was added dropwise to 10.0 g of ice-cooled methyl methacrylate (MMA). Then, the ice was removed, and 6.72 g of 2-aminoethanol was added dropwise over 30 minutes. At this time, care was taken so that the temperature of the liquid of the reaction liquid did not exceed 30 占 폚. After reacting overnight at room temperature, 25 g of pure water and 8.8 mL of a cation exchange resin (200CT H AG, manufactured by ORGANO Co., Ltd.) were neutralized to neutralize the reaction solution. The cation exchange resin was removed by filtration through a 1 mu m filter to obtain a HEMAA monomer aqueous solution. After several g samples were sampled from the solution, the concentration of the monomer was determined by the drying method, and pure water was added in an appropriate amount to obtain a 20% HEMAA monomer aqueous solution (yield: 68%).

<Synthesis of polyHEMAA>

To the mixture of 8.40 g of HEMAA aqueous solution and 8.30 g of pure water obtained above, 0.10 g of 10% APS aqueous solution was added and polymerization was carried out at 65 ° C for 10 hours under nitrogen atmosphere. After completion of the polymerization, the reaction solution cooled at room temperature was added dropwise to 30 g of acetone to obtain a polyHEMAA solid. The resulting solid was subjected to a series of steps of 15 g of acetone, followed by vacuum drying at 40 DEG C for 1 hour. The vacuum-dried solid was dissolved in 30 g of pure water, and then filtered through a 3 탆 filter. A few g of the solution was sampled, and the concentration of the polymer was determined by the drying method. An appropriate amount of pure water was added to the solution to finally obtain a 5% polyHEMAA aqueous solution (yield: 74%).

Example 12

<Preparation of monomers>

From the monomer synthesis of polyHEMAA, 2-aminoethanol was changed to 10.00 g of 3-amino-1,2-propanediol  Except that a 10% aqueous solution of DHPMAA monomer was obtained in the same manner (yield: 90%).

< Synthesis of polyDHPMAA >

From the polymer synthesis of polyHEMAA, a 5% polyDHPMAA aqueous solution (yield: 77%) was obtained in the same manner except that the HEMAA aqueous solution was changed to 8.40 g of DHPMAA aqueous solution.

Example 13

&Lt; Preparation of monomers (HEAA: GO = 1: 0.25 mol / mol)

0.16 g of glycidol was added dropwise over about 1 hour to a mixture of 1.00 g of the HEAA monomer heated to 70 占 폚 and 0.0025 g of N, N'-tetramethylethylenediamine (TEMED). After the completion of the dropwise addition, the temperature was maintained at 70 캜 for 10 minutes, and then the temperature was returned to room temperature.

< Synthesis of poly (HEAA-GO _0.25 ) >

21.9 g of pure water and 0.14 g of 10% APS aqueous solution were added to the reaction solution, and polymerization was carried out at 65 占 폚 for 10 hours under a nitrogen atmosphere. After completion of the polymerization, 3 탆 filter filtration was performed. The resulting solution was regarded as a 5.0% solution of poly (HEAA-GO _0.25 ) and used in the preparation of various experimental solutions / slurries.

<Molecular weight and molecular weight distribution>

The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the water soluble synthetic polymers of Examples 1 to 13, Reference Example 1 and Comparative Examples 1 to 5 were measured by GPC measurement. Conditions for GPC measurement are as follows. The values of the respective molecular weights are shown in Table 1.

GPC device: manufactured by Shimadzu Corporation, SCL-10A

Column: TSKgel GMPW _XL (× 1) + TSKgel G2500PW _XL (× 1), manufactured by Tosoh Corporation,

Eluent: 0.1 mol / kg NaCl, 20% methanol, pure water

Flow rate (flow rate): 0.6 mL / min

Detection method: RI + UV (254 nm)

Standard material: Polyethylene oxide

<Wettability test: water-soluble synthetic polymer>

A 1-inch silicon wafer was immersed (immersed) in 1% hydrofluoric acid for 2 minutes to remove the oxide film on the surface. After confirming that the surface sufficiently repelled water (wettability 0%), the wafer was immersed in a 4000 ppm aqueous solution of each of the water-soluble synthetic polymers of Examples 1 to 13, Reference Example 1 and Comparative Examples 1 to 5 (Reference Example 1 was HEC 3600 ppm , PEG 400 ppm) for 10 minutes. After 10 minutes, the wafer was taken out and lightly watered, and the wettability of the surface was confirmed. Here, the wettability refers to the percentage of the wetted surface area of the wafer surface as a whole. The results are shown in Table 1.

&Lt; Preparation of abrasive composition (slurry) >

The abrasive composition was prepared in the same manner as in Example 1 except that the silica particle slurry (particle diameter 17.8 nm by BET method; particle diameter D50 by dynamic light scattering method = 30.7 nm, SD = 10.0 nm) prepared by the method described in Japanese Patent No. 4712556, , An aqueous solution of a water-soluble polymer, and ion-exchange water.

&Lt; Polishing speed and wettability after polishing: abrasive composition >

The polishing was carried out under the following conditions, and the polishing rate was determined from the change in weight of the wafer before and after polishing. Further, on the wafer immediately after polishing, the surface was lightly poured with light water, and then the wettability of the surface was confirmed. The results are shown in Table 1.

Abrasive composition Composition: silica 1125 ppm, ammonia 100 ppm, water-soluble synthetic polymer 100 ppm (Reference Example 1: HEC 90 ppm, PEG 10 ppm)

Grinding machine: LGP-15S-I manufactured by Micro-Kiyoshi

Wafer: 4 inch silicon wafer

(P-type, resistivity of 5 to 18 m? 占 cm m, crystal face <111>

Surface pressure: 0.25 kgf / cm ²

Wafer rotation speed: 100 rpm

Pad: manufactured by Fuji Misa, SURFIN SSWI

Pad rotation speed: 30 rpm

Polishing slurry feed rate: 100 mL / min

Polishing time: 10 minutes

[Table 1]

Note: In the water soluble polymer, molecular weight, Mn and Mw cell of Reference Example 1, the numerical value at the upper part shows the molecular weight of HEC and the numerical value at the lower part shows the molecular weight of PEG, respectively.

As is clear from Table 1, it was confirmed that the wettability of the wafer surface after polishing was high in all the results of Examples 1 to 13.

<LPD evaluation>

Next, the LPD (Light Point Defect) density observed on the surface of the polished silicon wafer was evaluated using the polishing liquid containing the various water-soluble polymers as the polishing solution for finish polishing in the manufacturing process of the product silicon wafer did.

Specifically, the following experiment was conducted.

As a sample wafer for finish polishing test, a plurality of double-side polished silicon wafers having a diameter of 300 mm were prepared. A single-sided polishing process in which a surface of each sample wafer was removed by 1 mu m was carried out by using a single-sided mirror polishing (CMP) apparatus (not shown) to remove machining damage on the surface of each sample wafer. Thereafter, the surface of each sample wafer was subjected to finish polishing using the polishing solution of the five levels of polishing composition shown in Table 2 as the finally finished single side polishing treatment. The polishing conditions of the finish polishing are all the same. Specifically, the polishing surface 3 shown in FIG. 1 is used and the polishing cloth 3 made of suede and the polishing head 3 The polishing liquid was supplied from the polishing liquid supply nozzle 1 at a rate of about 500 ml / min while rotating the sample wafers 5 held by the polishing pad ⁴ And then subjected to finishing single side polishing treatment under the conditions. The preparation of the abrasive composition (slurry) was the same as that of Examples 1 to 13 except for the concentration of the water-soluble polymer and each component used.

The water-soluble synthetic polymer of Example 14 was the same as polyHEAA,

The water-soluble synthetic polymer of Example 15 had the same polyHEMAA as that of Example 11,

The water-soluble synthetic polymer of Example 16 had the same poly (HEAA-GO _0.25 ) as that of Example 13,

The water-soluble synthetic polymer of Comparative Example 6 had the same PAA,

As the water soluble synthetic polymer of Reference Example 2, the same HEC + PEG as that of Reference Example 1 was used.

Each of the finely polished sample wafers was subjected to RCA cleaning and then the density of LPDs of 35 nm or more observed on the surface of each sample wafer was measured using a surface defect inspection apparatus (Surfscan SP-2 manufactured by KLA-Tencor Corporation). The LPD results shown in Table 2 are average values of the measurement results of six sample wafers subjected to finish polishing at each level and are shown as relative values when the average value of Reference Example 1 is taken as 100. [

As can be seen from Table 2, the LPD density in Examples 14 to 16 was low. On the other hand, in the comparative example 6, any sample wafer had too many detection points and data overflowed and measurement was impossible.

[Table 2]

[Industrial applicability]

The abrasive composition of the present invention, the abrasive composition for a silicon wafer, and the method for producing a silicon wafer product can be used for stably supplying a silicon wafer having high quality surface characteristics (low residual fine particles, low LPD).

1: polishing liquid supply nozzle, 2: polishing platen, 3: polishing cloth, 4: polishing head, 5: sample wafer

Claims (13)

1. A polishing composition comprising silica particles, an alkaline substance, a water-soluble synthetic polymer, and water,
The water-soluble synthetic polymer has the structural unit (1)
The structural unit (1) has an oxygen-containing group and a carbonyl group,
The oxygen-containing group is an alcoholic hydroxyl group or a substituted or unsubstituted alkoxy group,
Wherein the carbonyl group is a keto group, a carbonyl group forming part of an ester bond, or a carbonyl group forming part of an amide bond. The method according to claim 1,
The structural unit (1) is derived from a monomer (?),
The above-mentioned monomer (?) Is a reactant obtained by reacting an epoxy compound with a compound having an ethylenic unsaturated bond and a hydroxyl group, and has a substituted alkoxy group. 3. The method according to claim 1 or 2,
The structural unit (1) comprises at least one unit selected from the units (1A) to (1F) represented by the following general formulas (1A) to (1F):

(In the general formulas 1A to 1F, X is CH ₂ , NH, or an oxygen atom, R ¹ is each independently a hydrogen atom or a methyl group, and each R ² independently represents a hydrogen atom, or a substituted or unsubstituted alkoxy group, m1~m10 are each independently an integer from 1 to 6, at least one of R ² in each unit being a substituent other than a hydrogen atom). The method of claim 3,
Each of the units (1A) to (1F) represented by the general formulas (1A) to (1F) has at least one hydroxyl group. The method according to claim 3 or 4,
Each of the units (1A) to (1F) represented by the general formulas (1A) to (1F) has at least two hydroxyl groups. 6. The method according to any one of claims 3 to 5,
Wherein in Formula 1A, Formula 1B, Formula 1C, Formula 1E, and Formula 1F, X is NH or an oxygen atom. 7. The method according to any one of claims 1 to 6,
Wherein the molar fraction of the constituent unit (1) relative to the total constituent units of the water soluble synthetic polymer is 50 mol% or more. 8. The method according to any one of claims 1 to 7,
The water-soluble synthetic polymer further comprises a constituent unit (2) represented by the following general formula (2):

(Wherein q is an integer of 1 to 6, X is CH ₂ , NH or an oxygen atom, and Z ¹ , Z ² , Z ³ , and Z ⁴ are each independently a hydrogen atom or a methyl group And Y ^- is an anion). 9. The method of claim 8,
Wherein the molar fraction of the constituent unit (2) relative to the total constituent units of the water soluble synthetic polymer is less than 50 mol%. An abrasive composition comprising silica particles, an alkaline substance, a water-soluble synthetic polymer, and water,
Wherein the water-soluble synthetic polymer is a reactant obtained by reacting the water-soluble synthetic polymer according to any one of claims 1 to 9 with an epoxy compound. 11. The method according to any one of claims 1 to 10,
Wherein the silica particles are prepared using alkoxysilane or a condensate thereof as a raw material and have a primary particle diameter of 10 to 40 nm and a secondary particle diameter of 20 to 80 nm. An abrasive composition for a silicon wafer, comprising the abrasive composition according to any one of claims 1 to 11. A method for producing a silicon wafer product, comprising the step of polishing a silicon wafer using the abrasive composition according to any one of claims 1 to 11.

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