Surface treatment composition, concentrated liquid of surface treatment composition, and surface treatment method

Abstract

The purpose of the present invention is to provide a surface treatment composition capable of reducing defects and haze on a surface of a silicon wafer after surface treatment is performed on the silicon wafer. The present disclosure relates to a surface treatment composition which contains a boron-containing compound, a water-soluble polymer, a basic compound, and water, and which is for use in surface treatment of a silicon wafer.

Description

Surface treatment composition, concentrated solution of surface treatment composition, and surface treatment method

[0001] The present invention relates to a surface treatment composition, a concentrated solution of the surface treatment composition, and a surface treatment method.

[0002] In recent years, with the increasing integration and speed of ULSI and other semiconductors used in computers, the design rules for semiconductor devices have become increasingly miniaturized. As a result, even minute defects on semiconductor substrates can negatively impact the performance of semiconductor devices. Therefore, the management of nano-order defects and smoothness, which were not previously considered problematic, is now required. Defects and smoothness can be evaluated using methods such as LPD (Light Point Defect) and haze level.

[0003] International Publication No. 2012 / 043418 (corresponding to US Patent Application Publication No. 2013 / 0181159) discloses a surface treatment composition comprising two surfactants having a specific relationship in weight-average molecular weight and content, a basic compound, and water, with a pH of 8 or higher, which reduces haze on the surface of a silicon wafer.

[0004] The surface treatment composition disclosed in International Publication No. 2012 / 043418 (corresponding to US Patent Application Publication No. 2013 / 0181159) can sufficiently reduce haze on the surface of a silicon wafer. However, with the increasing demand for higher quality semiconductor substrates, there is a need for technologies that can further reduce defects and haze on the surface of semiconductor substrates.

[0005] This invention has been made in view of the above circumstances, and its objective is to provide a surface treatment composition that can reduce defects and haze on the surface of a silicon wafer after surface treatment of the silicon wafer.

[0006] To solve the above problems, the inventors diligently conducted research. As a result, the inventors discovered that the above problems can be solved by a surface treatment composition containing a boron-containing compound, a water-soluble polymer, a basic compound, and water, and thus completed the present invention.

[0007] In other words, the above-mentioned problems of the present invention can be solved by the following means.

[0008] One embodiment of the present invention that can solve the above problems is a surface treatment composition used for surface treatment of silicon wafers, comprising a boron-containing compound, a water-soluble polymer, a basic compound, and water.

[0009] Another embodiment of the present invention that can solve the above problems is a surface treatment composition used for surface treatment of silicon wafers, comprising abrasive grains, a boron-containing compound, a water-soluble polymer, a basic compound, and water.

[0010] The embodiments for carrying out the present invention will be described in detail below. The embodiments shown herein are illustrative examples for embodying the technical idea of ​​the present invention and do not limit the present invention. Therefore, all other implementable forms, methods of use, and operating techniques that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, as well as in the scope of the invention described in the claims and its equivalents. The embodiments described herein can be combined in any way to form other embodiments. In this specification, "X to Y" indicating a range means "X or more and Y or less," and "weight" and "mass," "weight%" and "mass%," and "parts by weight" and "parts by mass" are treated as synonyms. In this specification, "A and / or B" includes forms A or B, and forms A and B. In this specification, unless otherwise specified, operations and measurements of physical properties, etc., are performed under conditions of room temperature (20°C or more and 25°C or less) / relative humidity 40% RH or more and 50% RH or less.

[0011] One embodiment of the present invention is a surface treatment composition for use in surface treatment of silicon wafers, comprising a boron-containing compound, a water-soluble polymer, a basic compound, and water.

[0012] The surface treatment composition containing the boron-containing compound, basic compound, and water-soluble polymer as described above can reduce defects and haze on the surface of a silicon wafer after surface treatment of the silicon wafer. The present inventors presume the mechanism by which such an effect is obtained by the surface treatment composition according to the above embodiment as follows. However, the following mechanism is merely speculation and does not limit the scope of the present invention thereby.

[0013] The water-soluble polymer is considered to protect the surface of the silicon wafer by adsorbing onto the silicon wafer during surface treatment. Here, since the surface treatment composition contains a boron-containing compound, it is considered that the water-soluble polymer (for example, a water-soluble polymer having a hydroxyl group such as polyvinyl alcohol) forms a crosslinked structure with the boron-containing compound and becomes more likely to adsorb onto the silicon wafer. At this time, in the presence of the basic compound, it is presumed that the water-soluble polymer and the boron-containing compound form a protective film of sufficient thickness and uniformity on the silicon wafer. That is, the protective film formed on the silicon wafer is thickened and made uniform by the composition of the surface treatment composition of the present invention, which may lead to suitable etching suppression and damage reduction in the silicon wafer, and reduce defects and haze on the surface of the silicon wafer.

[0014] As described above, the effects of the present invention are achieved by the surface treatment composition containing a boron-containing compound, a water-soluble polymer, a basic compound, and water.

[0015] In this specification, "surface treatment" includes polishing such as preliminary polishing, finish polishing, and rinse polishing and / or cleaning. The surface treatment composition according to this embodiment is suitably used for polishing (surface treatment) such as preliminary polishing, finish polishing, and rinse polishing. Therefore, the surface treatment process in which the surface treatment composition according to this embodiment is used includes (i) a method by preliminary polishing treatment or finish polishing treatment, and (ii) a method by rinse polishing treatment. That is, the surface treatment according to this embodiment is preferably performed by at least one selected from the group consisting of preliminary polishing, finish polishing treatment, and rinse polishing treatment, more preferably performed by finish polishing treatment and / or rinse polishing, and even more preferably performed by finish polishing treatment.

[0016] As described above, in the present invention, the "surface treatment composition" is a concept that includes both a polishing composition for polishing a silicon wafer (preliminary polishing or finish polishing) and a rinse composition (post chemical mechanical polishing cleaning composition) for surface treatment (rinse polishing) after polishing the silicon wafer. According to the present invention, by surface-treating a silicon wafer with the surface treatment composition according to this embodiment, defects and haze in the silicon wafer after surface treatment can be reduced.

[0017] [Boron-containing compound] The surface treatment composition according to this embodiment contains a boron-containing compound. The boron-containing compound acts on the water-soluble polymer to assist the water-soluble polymer in forming a protective film on the surface of the silicon wafer. The boron-containing compound is not particularly limited as long as it is a compound having boron, and examples thereof include borax, boron oxide, boric acid, borate, and the like.

[0018] Examples of boron oxides include diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide. Examples of borates include alkali metals, alkaline earth metals, elements of groups 4, 12, and 13 of the periodic table, and ammonium borates. Specifically, examples include alkali metal borate salts such as lithium borate, sodium borate, potassium borate, and cesium borate; alkaline earth metal borate salts such as magnesium borate, calcium borate, and barium borate; zirconium borate, zinc borate, aluminum borate, and ammonium borate.

[0019] According to one embodiment, in the surface treatment composition according to this embodiment, the boron-containing compound is one or more selected from the group consisting of boric acid, boron oxide, and salts thereof. According to one embodiment, in the surface treatment composition according to this embodiment, the boron-containing compound is preferably boric acid, diboron trioxide, or a borate, and most preferably boric acid. The boron-containing compound may be used alone or two or more may be used in combination.

[0020] According to one embodiment, the surface treatment composition according to this embodiment contains abrasive grains. In this case, the mass ratio of the boron-containing compound to the abrasive grains (mass of boron-containing compound / mass of abrasive grains) is preferably 0.0000001 to 1, more preferably 0.0000005 to 0.5, even more preferably 0.000001 to 0.1, particularly preferably 0.000005 to 0.05, and most preferably 0.000008 to 0.01. According to one embodiment, the mass ratio of the boron-containing compound to the abrasive grains (mass of boron-containing compound / mass of abrasive grains) is less than 0.1. Furthermore, according to one embodiment, the mass ratio of the boron-containing compound to the abrasive grains (mass of the boron-containing compound / mass of the abrasive grains) is 0.0000001 or more and less than 0.1, 0.0000001 or more and 0.05 or less, 0.0000001 or more and 0.01 or less, 0.000001 or more and less than 0.1, 0.000001 or more and 0.1 or less, 0.000001 or more and 0.01 or less, 0.000001 or more and 0.002 or less, or 0.000001 or more and 0.001 or less. According to one embodiment, the mass ratio of the boron-containing compound to the abrasive grains (mass of boron-containing compound / mass of abrasive grains) is 0.000001 or more and 0.1 or less, 0.000001 or more and 0.08 or less, 0.000001 or more and 0.05 or less, 0.00001 or more and 0.1 or less, 0.00001 or more and 0.08 or less, or 0.00001 or more and 0.05 or less. According to one embodiment, the mass ratio of the boron-containing compound to the abrasive grains (mass of boron-containing compound / mass of abrasive grains) is 0.0001 or more and 0.5 or less, 0.0001 or more and 0.3 or less, 0.0001 or more and less than 0.1, or 0.0001 or more and 0.05 or less. Within the above range, the etching effect on the entire silicon wafer is better controlled, and the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved.

[0021] When the surface treatment composition is used as is for surface treatment, the content of the boron-containing compound is preferably 0.1% by mass or less (1000 ppm by mass), more preferably less than 0.1% by mass (1000 ppm by mass), even more preferably 0.05% by mass (500 ppm by mass) or less, particularly preferably 0.01% by mass (100 ppm by mass) or less, particularly more preferably 0.001% by mass (10 ppm by mass) or less, and most preferably 0.0002% by mass (2 ppm by mass) or less. If the content of the boron-containing compound is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. Furthermore, when the surface treatment composition is used directly for surface treatment, the content of the boron-containing compound is preferably 0.0000001% by mass (0.001 ppm by mass) or more, more preferably 0.000001% by mass (0.01 ppm by mass) or more, even more preferably 0.000002% by mass (0.02 ppm by mass) or more, particularly preferably 0.000003% by mass (0.03 ppm by mass) or more, and most preferably 0.000005% by mass (0.05 ppm by mass) or more, based on the total mass (100% by mass) of the surface treatment composition. If the content of the boron-containing compound is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. The content of the basic compound is the total content of the boron-containing compound contained in the surface treatment composition.

[0022] When a surface treatment composition is diluted and used for surface treatment, i.e., when the surface treatment composition is a concentrated liquid, the content of the boron-containing compound in the concentrated liquid is not particularly limited, but is preferably 0.0000001% by mass or more, more preferably 0.000001% by mass or more, and even more preferably 0.00001% by mass or more. In this case, from the viewpoint of storage stability and filterability, the content of the boron-containing compound in the concentrated liquid of the surface treatment composition is preferably 1% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less. If the content of the boron-containing compound is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved.

[0023] [Water-soluble polymer] The surface treatment composition according to this embodiment contains a water-soluble polymer. The water-soluble polymer is thought to diffuse across the entire silicon wafer to control the etching action and improve the effect of reducing defects and haze on the silicon wafer surface.

[0024] In this specification, "water-soluble" means that the solubility in water (25°C) is 1 g / 100 mL or more.

[0025] The water-soluble polymer used in the surface treatment composition according to this embodiment is not particularly limited, and any polymer having at least one functional group selected from the group consisting of cationic groups, anionic groups, and nonionic groups in its molecule can be used. Examples include water-soluble polymers having anionic groups, water-soluble polymers having cationic groups, and water-soluble polymers having nonionic groups. In this specification, an anionic group means a functional group in which a counterion dissociates to become an anion. A cationic group means a functional group in which a counterion dissociates or combines with a cation species produced by the ionization of another ionic compound to become a cation. A nonionic group means a functional group that does not ionize. In one embodiment, a water-soluble polymer having a nonionic group is preferred.

[0026] According to one embodiment, the water-soluble polymer preferably contains hydroxyl groups, from the viewpoint of suitably controlling the etching action of the entire silicon wafer. Therefore, it is preferable that the polymer is a polymer containing hydroxyl groups. Examples of water-soluble polymers containing hydroxyl groups include polyvinyl alcohol-based polymers and polysaccharides. The water-soluble polymer containing hydroxyl groups may be used alone or in combination of two or more types.

[0027] 《Polymers containing hydroxyl groups》 〈Polysaccharides〉 Polysaccharides are compounds in which multiple monosaccharides are linked together. Examples include cellulose, guar gum, tamarind gum, xanthan gum, carrageenan, gum arabic, pullulan, pectin, agar, alginic acid, hyaluronic acid, chondroitin sulfate, tuberose polysaccharide, dextran, trehalose, amylose, amylopectin, dextrin, chitosan, lentinan, inulin, and starch. Polysaccharides may be modified. Examples include cellulose derivatives such as methylcellulose, ethylcellulose, propylcellulose, butylcellulose, hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, and carboxyethylcellulose; and starch derivatives such as starch acetate, hydroxypropyl starch, hydroxypropyl starch phosphate, octenyl succinate starch sugar, and dextrin fatty acid esters. As for the polysaccharides, cellulose derivatives and starch derivatives (for example, hydroxyethylcellulose) are preferred.

[0028] <Polyvinyl alcohol-based polymers> Polyvinyl alcohol-based polymers may contain only vinyl alcohol units (hereinafter also referred to as "VA units") as repeating units, or they may contain repeating units other than VA units (hereinafter also referred to as "non-VA units") in addition to VA units. The vinyl alcohol unit has the following chemical formula: -CH ２The structural part is represented by -CH(OH)-;. The polyvinyl alcohol polymer may be a random copolymer containing VA units and non-VA units, or it may be a block copolymer, a graft copolymer, or an alternating copolymer. The polyvinyl alcohol polymer may contain only one type of non-VA unit, or it may contain two or more types of non-VA units. In this specification, all water-soluble polymers having VA units are classified as polyvinyl alcohol polymers.

[0029] The polyvinyl alcohol-based polymer used in the surface treatment compositions disclosed herein may be unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA). Here, unmodified PVA is produced by hydrolysis (saponification) of polyvinyl acetate, and consists of repeating units (-CH) of the vinyl polymerized structure of vinyl acetate. ２ -CH (OCOCH) ３ This refers to a polyvinyl alcohol-based polymer that substantially does not contain repeating units other than VA units. The degree of saponification of the above unmodified PVA may be, for example, 60% or more, and may be 70% or more, 80% or more, or 90% or more from the viewpoint of water solubility. In some embodiments, unmodified PVA with a degree of saponification of 95% or more or 98% or more can be preferably used as the water-soluble polymer compound.

[0030] The polyvinyl alcohol-based polymer may be a modified PVA comprising VA units and non-VA units having at least one structure selected from oxyalkylene groups, carboxyl groups, (di)carboxylic acid groups, (di)carboxylic acid ester groups, phenyl groups, naphthyl groups, sulfo groups, amino groups, hydroxyl groups, amide groups, imide groups, nitrile groups, ether groups, ester groups, and salts thereof.

[0031] Examples of non-VA units that may be included in modified PVA include, but are not limited to, repeating units derived from N-vinyl type monomers or N-(meth)acryloyl type monomers, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms, and repeating units derived from (di)acetone compounds, as described later. One preferred example of the above N-vinyl type monomer is N-vinyl-2-pyrrolidone. One preferred example of the above N-(meth)acryloyl type monomer is N-(meth)acryloylmorpholine. The above alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group with 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The above vinyl ester of monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate. One preferred example of the above (di)acetone compound is diacetone(meth)acrylamide or acetylacetone.

[0032] The polyvinyl alcohol-based polymer may be a modified PVA in which some of the VA units contained in the polyvinyl alcohol-based polymer are acetalized with an aldehyde compound or a ketone compound. In a preferred embodiment of the technology disclosed herein, the acetalized modified PVA is a water-soluble polymer obtained by an acetalization reaction between the above-mentioned unmodified PVA and an aldehyde compound.

[0033] According to one embodiment, the aldehyde compound used to produce acetalized modified PVA is not particularly limited. In one preferred embodiment, the number of carbon atoms in the aldehyde compound is preferably 1 to 7, and more preferably 2 to 7.

[0034] Examples of the aldehyde compound include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde, tert-butylaldehyde, n-pentylaldehyde, hexylaldehyde; alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde. These can be used either alone or in combination of two or more. In addition, except for formaldehyde, the aldehyde compound may be one in which one or more hydrogen atoms are substituted with halogen or the like. Among them, linear or branched alkyl aldehydes are preferable from the viewpoint of high solubility in water and easy acetalization reaction, and among them, acetaldehyde, propionaldehyde, n-butylaldehyde, and n-pentylaldehyde are more preferable.

[0035] In addition to the above, aldehyde compounds having 8 or more carbon atoms such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde may be used as the aldehyde compound. Further, as the polyvinyl alcohol-based polymer, cation-modified polyvinyl alcohol having a cationic group such as a quaternary ammonium structure introduced therein may be used. Examples of the cation-modified polyvinyl alcohol include those in which a cationic group derived from a monomer having a cationic group such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt is introduced. Further, as the polyvinyl alcohol-based polymer, it may have a structural part represented by the chemical formula: -CH ２ -CH(CR １ (OR ４ )-CR ２ (OR ５ )-R ３ ). Here, R １ to R ３ each independently represent a hydrogen atom or an organic group, and R ４ and R ５ each independently represent a hydrogen atom or R ６ -CO-(wherein R ６R represents an alkyl group. For example, R in the above chemical formula. １ ~R ３ If at least one of the elements is an organic group, the organic group may be a linear or branched alkyl group having 1 to 8 carbon atoms. Also, R in the above chemical formula ６ This can be a linear or branched alkyl group having 1 to 8 carbon atoms.

[0036] In some embodiments, a modified PVA having a 1,2-diol structure in its side chain is used as the polyvinyl alcohol-based polymer. An example of the above modified PVA is the above R １ ~R ５ Examples include polymers containing non-VA units where the atom is a hydrogen atom (butenediol-vinyl alcohol copolymer (BVOH)).

[0037] The ratio of moles of VA units to the total number of moles of repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. While not particularly limited, in some embodiments, the ratio of moles of VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (for example, 95% or more, or 98% or more). It is also possible that substantially 100% of the repeating units constituting the polyvinyl alcohol-based polymer are VA units. Here, "substantially 100%" means that the polyvinyl alcohol-based polymer does not contain non-VA units, at least intentionally, and typically includes cases where the ratio of moles of non-VA units to the total number of moles of repeating units is less than 2% (for example, less than 1%), and is 0%. In some other embodiments, the ratio of moles of VA units to moles of total repeating units constituting the polyvinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

[0038] The content of VA units (by mass) in the polyvinyl alcohol polymer may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more. Although not particularly limited, in some embodiments, the content of VA units may be 50% by mass or more (for example, more than 50% by mass), 70% by mass or more, or 80% by mass or more (for example, 90% by mass or more, or 95% by mass or more, or 98% by mass or more). Substantially 100% by mass of the repeating units constituting the polyvinyl alcohol polymer may be VA units. Here, "substantially 100% by mass" means that, at least intentionally, non-VA units are not included as repeating units constituting the polyvinyl alcohol polymer, and typically means that the content of non-VA units in the polyvinyl alcohol polymer is less than 2% by mass (for example, less than 1% by mass). In some other embodiments, the VA unit content in the polyvinyl alcohol-based polymer may be, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 70% by mass or less.

[0039] A polyvinyl alcohol-based polymer may contain multiple polymer chains with different VA unit content within the same molecule. Here, a polymer chain refers to a part (segment) that constitutes a portion of a polymer molecule. For example, a polyvinyl alcohol-based polymer may contain polymer chain A, which has a VA unit content higher than 50% by mass, and polymer chain B, which has a VA unit content lower than 50% by mass (i.e., a non-VA unit content higher than 50% by mass), within the same molecule.

[0040] Polymer chain A may contain only VA units as repeating units, or it may contain non-VA units in addition to VA units. The VA unit content in polymer chain A may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the VA unit content in polymer chain A may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting polymer chain A may be VA units.

[0041] Polymer chain B may contain only non-VA units as repeating units, or it may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain B may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. In some embodiments, the content of non-VA units in polymer chain B may be 95% by mass or more, or 98% by mass or more. Substantially 100% by mass of the repeating units constituting polymer chain B may be non-VA units.

[0042] Examples of polyvinyl alcohol-based polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The above graft copolymer may be a graft copolymer in which polymer chain B (side chain) is grafted onto polymer chain A (main chain), or a graft copolymer in which polymer chain A (side chain) is grafted onto polymer chain B (main chain). In one embodiment, a polyvinyl alcohol-based polymer in which polymer chain B is grafted onto polymer chain A can be used.

[0043] Examples of polymer chain B include polymer chains whose main repeating unit is a repeating unit derived from an N-vinyl type monomer; polymer chains whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer; polymer chains whose main repeating unit is a repeating unit derived from vinyl dicarboxylates such as fumaric acid, maleic acid, and maleic anhydride; polymer chains whose main repeating unit is a repeating unit derived from aromatic vinyl monomers such as styrene and vinylnaphthalene; polymer chains whose main repeating unit is an oxyalkylene unit; and so on. In this specification, unless otherwise specified, a main repeating unit refers to a repeating unit that is present in an amount exceeding 50% by mass.

[0044] One preferred example of polymer chain B is a polymer chain whose main repeating unit is an N-vinyl type monomer, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl type monomers in the N-vinyl polymer chain is typically more than 50% by mass, and may be 70% by mass or more, 85% by mass or more, or 95% by mass or more. Substantially all of polymer chain B may consist of repeating units derived from N-vinyl type monomers.

[0045] Examples of N-vinyl monomers include monomers having a nitrogen-containing heterocyclic ring (e.g., a lactam ring) and N-vinyl chain amides. Specific examples of N-vinyl lactam monomers include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, 4-vinylmorpholin-3-one, N-vinyl-ε-caprolactam, N-vinyl-1,3-oxazine-2-one, and 4-vinyl-3,5-morpholindione. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide. Polymer chain B may be an N-vinyl polymer chain in which more than 50% by mass (e.g., 70% or more by mass, or 85% or more by mass, or 95% or more by mass) of its repeating units are N-vinyl-2-pyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinylpyrrolidone units.

[0046] Another example of polymer chain B is a polymer chain whose main repeating units are derived from N-(meth)acryloyl type monomers, i.e., an N-(meth)acryloyl polymer chain. The content of repeating units derived from N-(meth)acryloyl type monomers in an N-(meth)acryloyl polymer chain is typically more than 50% by mass, may be 70% or more by mass, 85% or more by mass, or 95% or more by mass. Substantially all of polymer chain B may consist of repeating units derived from N-(meth)acryloyl type monomers.

[0047] Examples of N-(meth)acryloyl type monomers include chain amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamides; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-n-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

[0048] Another example of polymer chain B is a polymer chain containing oxyalkylene units as the main repeating units, i.e., an oxyalkylene polymer chain. The content of oxyalkylene units in the oxyalkylene polymer chain is typically more than 50% by mass, may be 70% or more by mass, 85% or more by mass, or 95% or more by mass. Substantially all of the repeating units contained in polymer chain B may be oxyalkylene units.

[0049] Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be a repeating unit derived from the corresponding alkylene oxide. An oxyalkylene polymer chain may contain only one type of oxyalkylene unit, or two or more types. For example, an oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, these oxyalkylene units may be random copolymers of the corresponding alkylene oxides, block copolymers, or graft copolymers.

[0050] Further examples of polymer chain B include polymer chains containing repeating units derived from alkyl vinyl ethers (e.g., vinyl ethers having alkyl groups with 1 to 10 carbon atoms), polymer chains containing repeating units derived from monocarboxylate vinyl esters (e.g., vinyl esters of monocarboxylic acids having 3 or more carbon atoms), polymer chains in which a portion of the VA units are acetalized with aldehydes (e.g., alkylaldehydes having alkyl groups with 1 to 7 carbon atoms), and polymer chains into which cationic groups (e.g., cationic groups having a quaternary ammonium structure) are introduced.

[0051] The polyvinyl alcohol-based polymer that may be included in the surface treatment composition according to this embodiment may be unmodified PVA, modified PVA, or a combination of unmodified PVA and modified PVA. In the embodiment in which unmodified PVA and modified PVA are used in combination, the amount of modified PVA used relative to the total amount of polyvinyl alcohol-based polymer included in the surface treatment composition may be, for example, less than 95% by mass, 90% by mass or less, 75% by mass or less, 50% by mass or less, 30% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less. The surface treatment composition according to this embodiment can preferably be implemented, for example, by using only one or more types of unmodified PVA as the polyvinyl alcohol-based polymer.

[0052] Among these polyvinyl alcohol-based polymers, unmodified PVA, acetalized modified PVA, polyvinyl alcohol-polypyrrolidone copolymer, modified PVA containing oxyethylene units, and modified PVA containing repeating units derived from alkyl vinyl ether are more preferred.

[0053] The weight-average molecular weight of a water-soluble polymer containing hydroxyl groups is 0.1 × 10⁻⁶. ４ That concludes the explanation. According to some embodiments, the weight-average molecular weight of the water-soluble polymer containing hydroxyl groups (e.g., polysaccharide or polyvinyl alcohol-based polymer) is 0.2 × 10⁻⁶. ４ Preferably, it is 0.3 × 10 ４ It is more preferable that the above be the case, 0.4 × 10 ４ It is even more preferable that the above be the case, 0.5 × 10 ４ The above is particularly preferable. According to such embodiments, the effect of improving the surface quality of the surface-treated object is superior. According to some embodiments, the weight-average molecular weight of the water-soluble polymer containing hydroxyl groups (e.g., polyvinyl alcohol-based polymer) is 100 × 10 ４ It can be as follows: 50 x 10 ４ The following is also good: 30 x 10 ４ The following is also acceptable: 20 x 10 ４ The following is also acceptable: 10 x 10 ４ The following is preferable: 9 × 10 ４ More preferably, 8 × 10 ４ It is even more preferable that the following be the case: According to some embodiments, the weight-average molecular weight of the water-soluble polymer containing hydroxyl groups (e.g., polysaccharides) is 300 × 10⁻⁶. ４ It can be as follows: 150 x 10 ４ The following is also good: 100 x 10 ４ The following is also acceptable: 80 x 10 ４ The following is also acceptable: 60 x 10 ４ The following is preferable: 50 x 10 ４ More preferably, 30 × 10 ４The following is even more preferable. According to such embodiments, dispersion stability is improved. As the weight-average molecular weight of the water-soluble polymer containing hydroxyl groups (e.g., polysaccharides or polyvinyl alcohol-based polymers), the molecular weight calculated from the value based on gel permeation chromatography (GPC) (water-based, polyethylene glycol equivalent) can be used. As the measurement conditions for GPC, the value measured by the measurement method described below is used.

[0054] (GPC measurement conditions) Measurement device: HLC-8320GPC (Tosoh) Sample concentration: 0.01% by mass Column: TSKgel GMPWXL Detector: Differential refractive index Eluent: 100 mM sodium nitrate aqueous solution / acetonitrile = 10-8 / 0-2 Flow rate: 1 mL / min Measurement temperature: 40°C Molecular weight conversion: Polyethylene glycol equivalent Sample injection volume: 100 μL.

[0055] In cases where measurement by GPC is not possible, the molecular weight calculated from the molecular formula will be used as the weight-average molecular weight.

[0056] When the surface treatment composition is used as is for surface treatment (i.e., in a diluted solution state), the content of the water-soluble polymer containing hydroxyl groups is preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, and particularly preferably 0.001% by mass or more, based on the total mass (100% by mass) of the surface treatment composition, from the viewpoint of having a superior effect on improving surface quality. In this case, the concentration (content) of the water-soluble polymer containing hydroxyl groups is preferably 0.1% by mass or less, more preferably less than 0.1% by mass, even more preferably 0.05% by mass or less, and particularly preferably 0.01% by mass or less, based on the total mass (100% by mass) of the surface treatment composition, from the viewpoint of having a superior effect on improving surface quality. In other words, when the surface treatment composition is used as is for surface treatment (i.e., in a diluted solution state), the concentration (content) of the water-soluble polymer containing hydroxyl groups is preferably 0.00005% by mass or more and 0.1% by mass or less, more preferably 0.0001% by mass or more and 0.05% by mass or less, even more preferably 0.0005% by mass or more and 0.01% by mass or less, and particularly preferably 0.001% by mass or more and 0.01% by mass or less, based on the total mass (100% by mass) of the surface treatment composition.

[0057] When a surface treatment composition is diluted for use in surface treatment, that is, when the surface treatment composition is a concentrated liquid, the content of the water-soluble polymer containing hydroxyl groups is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, and particularly preferably 0.01% by mass or more, based on the total mass (100% by mass) of the surface treatment composition, from the viewpoint of improving storage stability. In this case, the concentration (content) of the water-soluble polymer containing hydroxyl groups in the surface treatment composition is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on the total mass (100% by mass) of the surface treatment composition, from the viewpoint of storage stability and filterability. In other words, when the surface treatment composition is in a concentrated liquid state, the concentration (content) of the water-soluble polymer containing hydroxyl groups is preferably 0.0001% by mass or more and 5% by mass or less, more preferably 0.0005% by mass or more and 3% by mass or less, even more preferably 0.001% by mass or more and 1% by mass or less, and particularly preferably 0.01% by mass or more and 1% by mass or less, based on the total mass (100% by mass) of the surface treatment composition.

[0058] When using water-soluble polymers containing two or more hydroxyl groups, the above concentration (content) refers to the total amount.

[0059] 《Other Water-Soluble Polymers》 According to one embodiment, the surface treatment composition according to this embodiment may further contain other water-soluble polymers different from the hydroxyl group-containing polymers described above (hereinafter also simply referred to as "other water-soluble polymers"). The other water-soluble polymers adhere to the surface of the object to be surface-treated and protect the surface of the object from uneven or excessive etching that may occur due to the action of the basic compound. This can further improve the quality of the surface of the object to be surface-treated.

[0060] Other water-soluble polymers may be any water-soluble polymers excluding polymers containing hydroxyl groups. According to one embodiment, other water-soluble polymers may be any water-soluble polymers excluding polyvinyl alcohol-based polymers (water-soluble polymers having VA units) and polysaccharides, and may have at least one functional group selected from the group consisting of cationic groups, anionic groups, and nonionic groups in the molecule. Examples include water-soluble polymers having anionic groups, water-soluble polymers having cationic groups, and water-soluble polymers having nonionic groups. Anionic groups, cationic groups, and nonionic groups are as described above. Other water-soluble polymers may be used individually or in combination of two or more.

[0061] The cationic group is not particularly limited, but examples include amino groups or salts thereof. Examples of water-soluble polymers having a cationic group include cationized cellulose, cationized guar gum, polydimethylmethylene pyrrolidinium chloride, dimethylmethylene pyrrolidinium chloride / (meth)acrylamide copolymer, (meth)acrylamide / (meth)acrylic acid / dimethyldiallylammonium chloride copolymer, N,N-dimethylaminoethyl (meth)acrylate diethyl sulfate, N,N-dimethyl(meth)acrylate polyethylene glycol, polyallylamine, glycidol-modified polyallylamine, methyldiallylamine-sulfur dioxide copolymer, and the like.

[0062] Examples of anionic groups include carboxyl groups, sulfol groups, phosphate groups, or salts thereof.

[0063] Examples of water-soluble polymers having a carboxyl group or a salt thereof (carboxyl group-containing water-soluble polymers) include poly(meth)acrylic acid and its derivatives, as well as their salts.

[0064] Examples of polymers having a sulfo group or a salt thereof (sulfo group-containing water-soluble polymers) include sulfonic acid-modified polyvinyl alcohol (sulfonic acid group-containing polyvinyl alcohol, sulfonic acid group-containing modified polyvinyl alcohol), sulfonic acid group-containing polystyrene such as polystyrene sulfonic acid (sulfonic acid group-containing modified polystyrene), sulfonic acid-modified polyvinyl acetate (sulfonic acid group-containing polyvinyl acetate, sulfonic acid group-containing modified polyvinyl acetate), sulfonic acid group-containing polyester (sulfonic acid group-containing modified polyester), copolymers of (meth)acrylic group-containing monomers and sulfonic acid group-containing monomers such as (meth)acrylic acid-sulfonic acid group-containing monomer copolymers, derivatives thereof, and salts thereof.

[0065] Phosphonic acid group (-P(=O)(OH) ２Examples of polymers having a group of (meth)acryloyloxymethyl phosphate or a salt thereof (phosphonic acid group-containing water-soluble polymers) include (co)polymers and derivatives thereof, as well as salts thereof, that contain constituent units composed of monomers such as 2-hydroxyethyl (meth)acryloyl phosphate and phenyl-2-acryloyloxyethyl phosphate. Also, examples of (co)polymers and derivatives thereof, as well as salts thereof, that contain constituent units composed of monomers such as (meth)acryloyloxymethyl phosphate, (meth)acryloyloxyethyl phosphate, (meth)acryloyloxypropyl phosphate, (meth)acryloyloxybutyl phosphate, (meth)acryloyloxypentyl phosphate, (meth)acryloyloxyhexyl phosphate, (meth)acryloyloxyoctyl phosphate, (meth)acryloyloxydecyl phosphate, (meth)acryloyloxylauryl phosphate, (meth)acryloyloxystearyl phosphate, and (meth)acryloyloxy-1,4-dimethylcyclohexyl phosphate, as well as salts thereof. Here, (co)polymer refers to a copolymer or homopolymer. Examples of monomers that constitute the constituent units of the copolymer other than the above-mentioned constituent units include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene; hydroxyl group-containing vinyl monomers such as hydroxystyrene, N-methylol(meth)acrylamide, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, polyethylene glycol mono(meth)acrylate, and 2-hydroxyethylpropenyl ether; and alkyl(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, dodecyl(meth)acrylate, hexadecyl(meth)acrylate, and eicosyl(meth)acrylate. In this specification, "having a phosphonic acid group or a salt thereof" means that the compound has a phosphonic acid group (-P(=O)(OH) ２It is sufficient that the substructure has a phosphonic acid group or a salt thereof, for example, the group of the phosphonic acid group or the salt thereof is a phosphate group (-O-P(=O)(OH) ２ ) This also includes cases where it exists in the form of a salt thereof.

[0066] Examples of water-soluble polymers having nonionic groups include compounds containing acyloxy groups, sulfo groups, vinyl structures, polyoxyalkylene structures, heterocyclic structures, amide structures, imide structures, etc., within the molecule. Examples of water-soluble polymers having nonionic groups include nitrogen atom-containing polymers and polyoxyalkylene structure-containing polymers.

[0067] Examples of nitrogen atom-containing polymers include polymers containing N-vinyl type monomer units; polymers containing N-(meth)acryloyl type monomer units; and the like. Examples of N-vinyl type polymers include polymers containing repeating units derived from monomers having nitrogen-containing heterocycles (e.g., lactam rings). Examples of such polymers include homopolymers and copolymers of N-vinyl lactam type monomers (e.g., copolymers in which the copolymerization ratio of N-vinyl lactam type monomer exceeds 50% by mass), and homopolymers and copolymers of N-vinyl chain amides (e.g., copolymers in which the copolymerization ratio of N-vinyl chain amide exceeds 50% by mass). Specific examples of N-vinyllactam monomers (i.e., compounds having a lactam structure and an N-vinyl group in one molecule) include N-vinyl-2-pyrrolidone (VP), N-vinyl-2-piperidone, 4-vinyl-3-morpholin-3-one, N-vinyl-ε-caprolactam (VC), N-vinyl-1,3-oxazine-2-one, and 4-vinyl-3,5-morpholindione. Specific examples of polymers containing N-vinyllactam monomer units include polyvinylpyrrolidone, polyvinylcaprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers (e.g., acrylic monomers, vinyl ester monomers, etc.), block copolymers containing polymer chains containing one or both of VP and VC, alternating copolymers, and graft copolymers. Specific examples of N-vinyl chain amides include N-vinylacetamide, N-vinylpropionic acid amide, and N-vinylbutyric acid amide.

[0068] Examples of N-(meth)acryloyl polymers include homopolymers and copolymers of N-(meth)acryloyl monomers (typically copolymers in which the copolymerization ratio of N-(meth)acryloyl monomers exceeds 50% by mass). Examples of N-(meth)acryloyl monomers include chain amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of chain-like amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-n-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of polymers containing chain-like amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide (for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by mass).

[0069] Examples of cyclic amides having an N-(meth)acryloyl group include N-acryloylmorpholine, N-acryloylthiomorpholine, N-acryloylpiperidine, N-acryloylpyrrolidine, N-methacryloylmorpholine, N-methacryloylpiperidine, and N-methacryloylpyrrolidine. Examples of polymers containing cyclic amides having an N-(meth)acryloyl group as monomer units include acryloylmorpholine polymers. Typical examples of acryloylmorpholine polymers include homopolymers of N-acryloylmorpholine (ACMO) (poly-N-acryloylmorpholine (PACMO)) and copolymers of ACMO (for example, copolymers in which the copolymerization ratio of ACMO exceeds 50% by mass). In acryloylmorpholine polymers, the ratio of moles of ACMO units to moles of total repeating units is usually 50% or more, and is preferably 80% or more (e.g., 90% or more, typically 95% or more). The total repeating units of the water-soluble polymer may be substantially composed of ACMO units.

[0070] Examples of polyoxyalkylene structure-containing polymers include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, oxyalkylene polymers such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polytetramethylene glycol; polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, poly Polyoxyalkylene alkyl ethers such as oxyethylene isostearyl ether and polyoxyethylene oleyl ether (preferably polyoxyethylene alkyl ethers); polyoxyalkylene alkylphenyl ethers such as polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, and polyoxyethylene styrene phenyl ether (preferably polyoxyethylene alkylphenyl ethers); polyoxyalkylene alkylamines such as polyoxyethylene laurylamine, polyoxyethylene stearylamine, and polyoxyethylene oleylamine (preferably polyoxyethylene alkylamines); polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, and polyoxyethylene dioleate (preferably polyoxyethylene fatty acid esters);Examples include polyoxyethylene sorbitan fatty acid esters (preferably polyoxyethylene sorbitan fatty acid esters) such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate; and polyoxyalkylene derivatives such as polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil. Among these, preferred polyoxyalkylene structure-containing polymers include block copolymers of EO and PO (especially PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ethers).

[0071] Furthermore, when other water-soluble polymers are in the form of salts, examples of salts are not particularly limited, but include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as calcium salts and magnesium salts, amine salts, and ammonium salts.

[0072] The weight-average molecular weight (Mw) of other water-soluble polymers is 0.5 × 10⁻⁶. ４ That concludes the explanation. From the viewpoint of protecting the polished surface, the above Mw is 1.0 × 10 ４ The above is appropriate, 1.5 × 10 ４ It may be more than 2 x 10 ４ It may be more than or equal to, for example, 5 x 10 ４ The above is also acceptable: 10 x 10 ４ The above is also acceptable. Furthermore, from the perspective of reducing residue, for example, approximately 200 x 10 ４ The following is acceptable, approximately 150 x 10 ４ The following is suitable, and from the viewpoint of reducing residue, it is preferably about 100 x 10 ４ The following is approximately 50 x 10 ４ The following is also acceptable.

[0073] For other water-soluble polymers, the weight-average molecular weight (Mw) can be calculated from values ​​based on gel permeation chromatography (GPC) (water-based, polyethylene glycol equivalent). The GPC measurement conditions can be the same as those used for the water-soluble polymers containing hydroxyl groups mentioned above.

[0074] Other water-soluble polymers can be used individually or in combination of two or more. Furthermore, commercially available or synthesized water-soluble polymers may be used.

[0075] As for other water-soluble polymers, from the viewpoint of better exhibiting the intended effects of the present invention, homopolymers of N-acryloylmorpholine (ACMO) (poly-N-acryloylmorpholine (PACMO)) and polyoxyalkylene structure-containing polymers are more preferred.

[0076] When the surface treatment composition is used as is for surface treatment (i.e., in a diluted solution state), the concentration (content) of other water-soluble polymers in the surface treatment composition is preferably 0.0001% by mass or more, more preferably 0.0003% by mass or more, even more preferably 0.0005% by mass or more, particularly preferably 0.001% by mass or more, and most preferably 0.003% by mass or more, based on the total mass (100% by mass) of the surface treatment composition. In this case, the upper limit of the concentration (content) of other water-soluble polymers in the surface treatment composition is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.2% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. In other words, when the surface treatment composition is used as is for surface treatment (i.e., in the state of a diluted solution), the concentration (content) of other water-soluble polymers is preferably 0.0001% by mass or more and 5% by mass or less, more preferably 0.0003% by mass or more and 1% by mass or less, even more preferably 0.0005% by mass or more and 0.5% by mass or less, even more preferably 0.001% by mass or more and 0.2% by mass or less, and particularly preferably 0.003% by mass or more and 0.1% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. When the surface treatment composition is used as is for surface treatment (i.e., in the state of a diluted solution), the concentration (content) of other water-soluble polymers in the surface treatment composition may be 0.001% by mass or more and 0.05% by mass or less, or 0.003% by mass or more and 0.05% by mass or less.

[0077] When a surface treatment composition is diluted and used for surface treatment, that is, when the surface treatment composition is a concentrated liquid, the content (concentration) of other water-soluble polymers in the concentrated liquid is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more. In this case, although the content (concentration) of other water-soluble polymers in the concentrated liquid of the surface treatment composition is not particularly limited, from the viewpoint of storage stability, it is preferably 15% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. That is, when the surface treatment composition is in the state of a concentrated liquid, the content (concentration) of other water-soluble polymers in the concentrated liquid is preferably 0.001% by mass or more and 15% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less, and even more preferably 0.01% by mass or more and 3% by mass or less.

[0078] When using two or more other water-soluble polymers, the above concentration (content) refers to their total amount.

[0079] 《Embodiment Regarding Water-Soluble Polymers》 In the surface treatment composition according to this embodiment, when the water-soluble polymer includes a water-soluble polymer containing hydroxyl groups (for example, a polyvinyl alcohol-based polymer) and other water-soluble polymers, the mass ratio of the water-soluble polymer containing hydroxyl groups to the other water-soluble polymers (mass of water-soluble polymer containing hydroxyl groups: mass of other water-soluble polymers) is preferably 20:80 to 99:1, more preferably 25:75 to 98:2, even more preferably 30:70 to 97:3, particularly preferably 35:65 to 95:5, and most preferably 40:60 to 90:10. Within the above range, the etching effect on the entire silicon wafer is better controlled, and the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. When two or more water-soluble polymers are used as the water-soluble polymer containing hydroxyl groups, the total mass of these is considered the mass of the water-soluble polymer containing hydroxyl groups. Similarly, when two or more other water-soluble polymers are used as the other water-soluble polymers, the total mass of these is considered the mass of the other water-soluble polymers.

[0080] According to one embodiment, in the surface treatment composition according to this embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is preferably 0.00001 to 10, more preferably 0.0001 to 5, even more preferably 0.0003 to 1, particularly preferably 0.0005 to 0.8, and most preferably 0.0008 to 0.7. According to one embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is 0.0001 or more and 0.6 or less, 0.0001 or more and 0.5 or less, 0.0001 or more and 0.3 or less, 0.0001 or more and 0.2 or less, 0.0001 or more and 0.1 or less, 0.0001 or more and 0.05 or less, 0.0001 or more and 0.01 or less, 0.0001 or more and 0.005 or less, 0.0001 or more and 0.004 or less, 0.0001 or more and less than 0.004, 0.0001 or more and 0.003 or less, or 0.0001 or more and 0.002 or less. According to one embodiment, in the surface treatment composition according to this embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is preferably 0.0001 to 10, more preferably 0.0005 to 5, even more preferably 0.001 to 3, particularly preferably 0.005 to 2, and most preferably 0.01 to 1. According to one embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is less than 0.004. Within the above range, the etching effect on the entire silicon wafer is better controlled, and the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. When two or more water-soluble polymers are used as the water-soluble polymer, the total mass of these polymers is considered the mass of the water-soluble polymer.

[0081] According to one embodiment, in the surface treatment composition according to this embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer containing hydroxyl groups (mass of the boron-containing compound / mass of the water-soluble polymer containing hydroxyl groups) is preferably 0.00001 to 10, more preferably 0.0001 to 5, even more preferably 0.0003 to 1, particularly preferably 0.0005 to 0.8, and most preferably 0.0008 to 0.7. According to one embodiment, when the water-soluble polymer containing hydroxyl groups is a polyvinyl alcohol-based polymer, the mass ratio of the boron-containing compound to the water-soluble polymer containing hydroxyl groups (mass of the boron-containing compound / mass of the water-soluble polymer containing hydroxyl groups) is 0.0001 to 0.6, 0.0001 to 0.5, 0.0001 to 0.3, 0.0001 to 0.2, 0.0001 to 0.1, 0.0001 to 0.05, 0.0001 to 0.01, 0.0001 to 0.07, 0.0001 to 0.005, 0.0001 to 0.004, 0.0001 to less than 0.004, 0.0001 to 0.003, or 0.0001 to 0.002. According to one embodiment, in the surface treatment composition according to this embodiment, when the water-soluble polymer containing hydroxyl groups is a polysaccharide, the mass ratio of the boron-containing compound to the water-soluble polymer containing hydroxyl groups (mass of the boron-containing compound / mass of the water-soluble polymer containing hydroxyl groups) is preferably 0.0001 to 10, more preferably 0.0005 to 5, even more preferably 0.001 to 3, particularly preferably 0.005 to 2, and most preferably 0.01 to 1. According to one embodiment, the mass ratio of the boron-containing compound to the water-soluble polymer containing hydroxyl groups (mass of the boron-containing compound / mass of the water-soluble polymer containing hydroxyl groups) is less than 0.004. Within the above range, the etching effect on the entire silicon wafer is better controlled, and the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. Note that when two or more water-soluble polymers are used as the water-soluble polymer containing hydroxyl groups, the above mass refers to the total amount of these polymers.

[0082] When the surface treatment composition is used directly for surface treatment, the content of the water-soluble polymer is preferably 0.1% by mass or less, more preferably 0.02% by mass or less, and even more preferably 0.01% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. Furthermore, the content of the water-soluble polymer is preferably 0.0001% by mass or more, more preferably 0.0003% by mass or more, and even more preferably 0.0006% by mass or more, based on the total mass (100% by mass) of the surface treatment composition. If the content of the water-soluble polymer is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. The content of the water-soluble polymer is the total content of water-soluble polymers contained in the surface treatment composition, and for example, if it contains a water-soluble polymer containing a hydroxyl group and other water-soluble polymers, it is the sum of the contents of each.

[0083] When a surface treatment composition is diluted for use in surface treatment, i.e., when the surface treatment composition is a concentrated liquid, the content of water-soluble polymers is preferably 1% by mass or less from the viewpoint of storage stability and filterability. Furthermore, from the viewpoint of taking advantage of the benefits of a concentrated liquid, the content of water-soluble polymers is preferably 0.001% by mass or more. The content of water-soluble polymers refers to the total content of water-soluble polymers contained in the surface treatment composition, and for example, if it contains water-soluble polymers containing hydroxyl groups and other water-soluble polymers, it is the sum of the content of each.

[0084] [Basic Compounds] The surface treatment composition according to this embodiment contains basic compounds. Basic compounds play a role in chemically polishing or rinsing the silicon wafer and contribute to improving the polishing or rinsing ability of the surface treatment composition. Examples of basic compounds include organic basic compounds and / or inorganic basic compounds. Preferably, the surface treatment composition according to this embodiment contains one or more basic compounds selected from the group consisting of organic basic compounds and inorganic basic compounds.

[0085] Examples of organic basic compounds include ammonia, amines, and quaternary ammonium salts. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole. Examples of quaternary ammonium salts include halides of quaternary ammonium (F salts, Cl salts, Br salts, or I salts) such as tetramethylammonium fluoride, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, and tetrabutylammonium bromide; and quaternary ammonium hydroxides such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, and tetrabutylammonium hydroxide. As for organic basic compounds, ammonia and quaternary ammonium hydroxides are preferred, with ammonia being more preferred, from the viewpoint of reducing defects and haze on the silicon wafer surface after surface treatment.

[0086] Examples of inorganic basic compounds include hydroxides, carbonates, or bicarbonates of alkali metals such as lithium, sodium, and potassium, or alkaline earth metals (Group 2 metals) such as beryllium, magnesium, calcium, strontium, and barium. Specific examples of alkali metal or alkaline earth metal (Group 2 metal) hydroxides, carbonates, or bicarbonates include lithium hydroxide, sodium hydroxide, potassium hydroxide, potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate. From the viewpoint of reducing defects and haze on the silicon wafer surface, alkali metal or alkaline earth metal (Group 2 metal) carbonates or bicarbonates are preferred as inorganic basic compounds, alkali metal carbonates are more preferred, alkali metal carbonates are even more preferred, and potassium carbonate is particularly preferred.

[0087] In the surface treatment composition according to this embodiment, the basic compound may be used alone or in a mixture of two or more. When two or more basic compounds are included, the content of the basic compound refers to their total amount. In the surface treatment composition according to this embodiment, the basic compound may be a combination of an organic basic compound and an inorganic basic compound.

[0088] When the surface treatment composition is used as is for surface treatment, the content of basic compounds is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. If the content of basic compounds is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. Furthermore, when the surface treatment composition is used as is for surface treatment, the content of basic compounds is preferably 0.0001% by mass or more, more preferably 0.0003% by mass or more, and even more preferably 0.0006% by mass or more, based on the total mass (100% by mass) of the surface treatment composition. If the content of basic compounds is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. The content of basic compounds refers to the total content of basic compounds contained in the surface treatment composition.

[0089] When a surface treatment composition is diluted for use in surface treatment, i.e., when the surface treatment composition is a concentrated solution, the content of basic compounds in the concentrated solution is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, and particularly preferably 0.05% by mass or more. In this case, from the viewpoint of storage stability and filterability, the content of basic compounds in the concentrated solution of the surface treatment composition is preferably 45% by mass or less, more preferably 15% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less. If the content of basic compounds is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved.

[0090] [Water] The surface treatment composition according to this embodiment contains water as a dispersion medium to disperse or dissolve each component. From the viewpoint of preventing contamination of the surface to be treated and inhibiting the action of other components, it is preferable that the water contains as few impurities as possible. As such water, for example, water in which the total content of transition metal ions is 100 ppb or less is preferred. Here, the purity of the water can be increased by operations such as removing impurity ions using ion exchange resin, removing foreign matter by filtration, and distillation. Specifically, as water, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, or distilled water.

[0091] For the dispersion or dissolution of each component, water may be used as a mixed solvent with an organic solvent. In this case, examples of organic solvents that can be used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, all of which are miscible with water. Alternatively, these organic solvents may be used without mixing with water to disperse or dissolve each component, and then mixed with water. These organic solvents can be used individually or in combination of two or more.

[0092] When the surface treatment composition is used as is for surface treatment, the water content is preferably 99.99% by mass or less, more preferably 99.98% by mass or less, and even more preferably 99.95% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. If the water content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. If the water content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. When the surface treatment composition is used as is for surface treatment, the water content is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total mass (100% by mass) of the surface treatment composition.

[0093] When a surface treatment composition is diluted for use in surface treatment, i.e., when the surface treatment composition is a concentrated liquid, the water content in the concentrated liquid is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 95% by mass or more. In this case, from the viewpoint of storage stability and filterability, the water content in the concentrated liquid of the surface treatment composition is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less. If the water content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment will be further improved.

[0094] [pH] The pH of the surface treatment composition according to this embodiment is preferably 7.0 or higher, more preferably 7.5 or higher, even more preferably 8.0 or higher, particularly preferably 8.5 or higher, and most preferably 9.0 or higher. The pH of the surface treatment composition is preferably 12.5 or lower, more preferably 12.0 or lower, even more preferably 11.8 or lower, particularly preferably 11.6 or lower, and most preferably 11.5 or lower. That is, the pH of the surface treatment composition is preferably 7.0 or higher and 12.5 or lower, more preferably 7.5 or higher and 12.0 or lower, even more preferably 8.0 or higher and 11.8 or lower, particularly preferably 8.5 or higher and 11.6 or lower, and most preferably 9.0 or higher and 11.5 or lower. In one embodiment, the pH of the surface treatment composition is 9.5 or higher and 11.0 or lower. If the pH of the surface treatment composition is within this range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved.

[0095] The pH of the surface treatment composition can be measured using, for example, a pH meter (e.g., a pH meter manufactured by Horiba, Ltd. (model number: LAQUA)). Specific types of pH adjusting agents are described in detail below.

[0096] [Optional Components] The surface treatment composition according to this embodiment may further contain known additives that can be used in surface treatment compositions, such as abrasive particles, chelating agents, pH adjusters, antifungal agents (preservatives), and surfactants, to the extent that they do not impair the effects of the present invention. Abrasive particles, pH adjusters, antifungal agents (preservatives), and surfactants will be described below. Oxidizing agents will also be described.

[0097] [Abrasive particles] The surface treatment composition according to this embodiment may further contain abrasive particles. The abrasive particles have the effect of mechanically polishing or rinsing the surface to be treated, and improve the smoothness of the surface to be treated by the surface treatment composition.

[0098] When the surface treatment composition according to this embodiment contains abrasive grains, it becomes suitable for polishing processes such as chemical mechanical polishing (for example, a polishing composition). The surface treatment composition according to this embodiment is less likely to corrode metals and has excellent residue removal performance, making it very suitable as a surface treatment composition for polishing processes (pre-polishing and finish polishing). On the other hand, the surface treatment composition according to this embodiment is less likely to corrode metals and also has excellent residue removal performance when used for surface treatment after chemical mechanical polishing (rinse polishing), making it very suitable as a surface treatment composition with a low abrasive grain content (for example, 0.3% by mass or less) or without abrasive grains (for example, a rinse polishing composition).

[0099] The abrasive particles included in the surface treatment composition according to this embodiment are not particularly limited, and examples include inorganic particles, organic particles, organic-inorganic composite particles, etc. Among these, inorganic particles are preferred. In a surface treatment composition according to a preferred embodiment of this embodiment, the abrasive particles include inorganic particles. The inorganic particles are not particularly limited, but examples include oxide particles such as silica particles, alumina particles, cerium oxide particles, chromium oxide particles, titanium dioxide particles, zirconium oxide particles, magnesium oxide particles, manganese dioxide particles, zinc oxide particles, and red iron oxide particles; nitride particles such as silicon nitride particles and boron nitride particles; carbide particles such as silicon carbide particles and boron carbide particles; diamond particles; carbonates such as calcium carbonate and barium carbonate, etc. Among these, silica particles are more preferred, colloidal silica and fumed silica are even more preferred, and colloidal silica is particularly preferred.

[0100] Methods for producing colloidal silica include the sodium silicate method and the sol-gel method, and colloidal silica produced by either method can be suitably used as colloidal silica according to this embodiment. However, from the viewpoint of reducing metal impurities, colloidal silica produced by the sol-gel method is preferred. Colloidal silica produced by the sol-gel method is preferred because it contains less metal impurities that have the property of diffusing in semiconductors and corrosive ions such as chloride ions. Colloidal silica can be produced by the sol-gel method using conventionally known methods, and specifically, colloidal silica can be obtained by performing a hydrolysis-condensation reaction using a hydrolyzable silicon compound (for example, alkoxysilane or its derivatives) as a raw material. In addition, commercially available colloidal silica may be used.

[0101] The shape of the abrasive grains is not particularly limited and may be spherical or non-spherical. Specific examples of non-spherical shapes include polygonal prisms such as triangular or square prisms, cylindrical shapes, cylindrical shapes with a bulge in the center, donut shapes with a hole in the center, plate shapes, so-called cocoon shapes with a constriction in the center, so-called aggregate spherical shapes where multiple particles are integrated, so-called konpeito shapes with multiple protrusions on the surface, rugby ball shapes, and many other shapes, and are not particularly limited.

[0102] While not particularly limited, the average aspect ratio of the major axis to minor axis of the abrasive grains (average aspect ratio) is, in principle, 1.0 or higher, preferably 1.05 or higher, and more preferably 1.1 or higher. A higher polishing rate can be achieved by increasing the average aspect ratio. Furthermore, from the viewpoint of reducing scratches, the average aspect ratio of the abrasive grains is preferably 3.0 or lower, more preferably 2.0 or lower, and even more preferably 1.5 or lower.

[0103] The shape (outer shape) and average aspect ratio of abrasive grains can be determined, for example, by electron microscopy observation. A specific procedure for determining the average aspect ratio is to use a scanning electron microscope (SEM) to draw the smallest rectangle circumscribing each particle image for a predetermined number of silica particles (e.g., 200 particles) whose individual particle shapes can be recognized. Then, for the rectangle drawn for each particle image, the ratio of the major axis to the minor axis (aspect ratio) is calculated by dividing the length of the major side (major axis) by the length of the minor side (minor axis). The average aspect ratio can be obtained by taking the arithmetic mean of the aspect ratios of the predetermined number of particles.

[0104] The abrasive particles contained in the surface treatment composition may be in the form of primary particles or secondary particles formed by the association of multiple primary particles. Furthermore, a mixture of primary and secondary abrasive particles may be present. In one preferred embodiment, at least some of the abrasive particles are contained in the surface treatment composition in the form of secondary particles.

[0105] The average primary particle diameter of the abrasive grains contained in the surface treatment composition according to this embodiment is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 15 nm or more, and particularly preferably 20 nm or more. Furthermore, the average primary particle diameter of the abrasive grains contained in the surface treatment composition according to this embodiment is, for example, 120 nm or less, may be 100 nm or less, preferably 80 nm or less, more preferably 70 nm or less, even more preferably 60 nm or less, particularly preferably 50 nm or less, even more preferably 40 nm or less, and most preferably 30 nm or less. By having the average primary particle diameter of the abrasive grains within the above range, the intended effects of the present invention can be further improved.

[0106] The average secondary particle diameter of the abrasive grains contained in the surface treatment composition according to this embodiment is preferably 20 nm or more, more preferably 30 nm or more, even more preferably 40 nm or more, and particularly preferably 45 nm or more. Furthermore, the average secondary particle diameter of the abrasive grains contained in the surface treatment composition according to this embodiment is preferably, for example, 150 nm or less, more preferably 120 nm or less, even more preferably 100 nm or less, particularly preferably 80 nm or less, and most preferably 55 nm or less. By having the average secondary particle diameter of the abrasive grains within the above range, the intended effects of the present invention can be further improved.

[0107] Furthermore, the preferred range for the average primary particle diameter and average secondary particle diameter of the abrasive grains mentioned above is also the preferred range for the average primary particle diameter and average secondary particle diameter of the abrasive grains contained in the raw material dispersion used in its preparation.

[0108] In this specification, the average primary particle diameter is defined as the average primary particle diameter (nm) = 6000 / (true density (g / cm³)) calculated from the specific surface area (BET value) measured by the BET method. ３ ) × BET value (m ２This refers to the particle diameter (BET particle diameter) calculated by the formula ( / g). The specific surface area can be measured, for example, using "Flow Sorb II 2300" manufactured by Micromerities. The average secondary particle diameter of the abrasive grains can be measured, for example, by dynamic light scattering, and can be measured using "NanoTrack (registered trademark) UPA-UT151" manufactured by Nikkiso Co., Ltd.

[0109] The surface treatment composition according to this embodiment may not contain abrasive grains, but if abrasive grains are used, the abrasive grain content is as follows.

[0110] When the surface treatment composition is used as is for surface treatment, the abrasive content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and most preferably 0.5% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. If the abrasive content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. Also, when the surface treatment composition is used as is for surface treatment, the abrasive content is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, and most preferably 0.05% by mass or more, based on the total mass (100% by mass) of the surface treatment composition. If the abrasive content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. The abrasive content refers to the total content of abrasive grains contained in the surface treatment composition.

[0111] When a surface treatment composition is diluted and used for surface treatment, i.e., when the surface treatment composition is a concentrated liquid, the content of abrasive particles in the concentrated liquid is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 1% by mass or more, and most preferably 2% by mass or more. In this case, from the viewpoint of storage stability and filterability, the content of abrasive particles in the concentrated liquid of the surface treatment composition is preferably 50% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 9% by mass or less. If the content of abrasive particles is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment will be further improved.

[0112] According to one embodiment, the surface treatment composition according to this embodiment may contain silica particles and other abrasive particles other than silica particles as abrasive particles. However, when the surface treatment composition according to this embodiment is in a diluted solution state, the content of the other abrasive particles is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the silica particles and the other abrasive particles. The most preferred embodiment is one in which the content of other abrasive particles is 0% by mass, that is, an embodiment that does not contain any abrasive particles other than silica particles.

[0113] [Chelating Agent] The surface treatment composition according to this embodiment may contain a chelating agent. The chelating agent can perform polydentate coordination with metal ions and increase the solubility of the metal ions in the surface treatment composition, thereby contributing to the removal of particle residues such as abrasive grains from the polished surface after polishing. Examples of chelating agents include aminocarboxylic acid-based chelating agents and organic phosphonic acid-based chelating agents.

[0114] Examples of aminocarboxylic acid-based chelating agents include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetic acid, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate.

[0115] Organic phosphonic acid chelating agents include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(methylenephosphonic acid), ethylenediaminetetrakis(methylenephosphonic acid) (EDTPO), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, and α-methylphosphonosuccinic acid.

[0116] Of these, organic phosphonic acid chelating agents are more preferred. Among these, preferred chelating agents include ethylenediaminetetrakis(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and diethylenetriaminepentaacetic acid. Particularly preferred chelating agents include ethylenediaminetetrakis(methylenephosphonic acid) and diethylenetriaminepenta(methylenephosphonic acid).

[0117] Chelating agents can be used individually or in combination of two or more. When two or more chelating agents are included, the chelating agent content refers to their total amount.

[0118] When the surface treatment composition is used as is for surface treatment, the chelating agent content is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less, based on the total mass (100% by mass) of the surface treatment composition. If the chelating agent content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved. Furthermore, when the surface treatment composition is used as is for surface treatment, the chelating agent content is preferably 0.0001% by mass or more, more preferably 0.0002% by mass or more, even more preferably 0.0003% by mass or more, and particularly preferably 0.0004% by mass or more, based on the total mass (100% by mass) of the surface treatment composition. Most preferably 0.0005% by mass or more. If the chelating agent content is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment is further improved.

[0119] When a surface treatment composition is diluted and used for surface treatment, i.e., when the surface treatment composition is a concentrated liquid, the content of the chelating agent in the concentrated liquid is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, particularly preferably 0.06% by mass or more, and most preferably 0.08% by mass or more. In this case, from the viewpoint of storage stability and filterability, the content of the chelating agent in the concentrated liquid of the surface treatment composition is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less. If the content of the chelating agent is within the above range, the effect of reducing defects and haze on the silicon wafer surface after surface treatment will be further improved.

[0120] [pH Adjuster] In the surface treatment composition of this embodiment, the pH can be adjusted by the components described above, but the pH may be further adjusted to a desired level using a pH adjuster. Therefore, the surface treatment composition of this embodiment may further contain a pH adjuster. Examples of pH adjusters include compounds other than the basic compounds (organic basic compounds and / or inorganic basic compounds) and chelating agents described above, such as inorganic acids and organic acids. These pH adjusters may be used individually or in combination of two or more. The content of the pH adjuster can be selected by appropriately adjusting it within the range that achieves the effects of the present invention.

[0121] Specific examples of inorganic acids that can be used as pH adjusters include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Of these, hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid are preferred, with nitric acid being more preferred.

[0122] Specific examples of organic acids that can be used as pH adjusters include, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furanic acid, 2,5-franic acid, 3-furanic acid, 2-tetrahydrofuranic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, 10-camphorsulfonic acid, and isethionic acid.

[0123] As a pH adjuster, alkali metal salts of inorganic or organic acids may be used instead of or in combination with inorganic or organic acids. In the case of combinations of weak acid and strong base, strong acid and weak base, or weak acid and weak base, a pH buffering effect can be expected.

[0124] [Antifungal agents] Antifungal agents (preservatives) are not particularly limited and can be appropriately selected according to the desired use and purpose. Specifically, examples include isothiazoline preservatives such as 1,2-benzoisothiazole-3(2H)-one (BIT), 2-methyl-4-isothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3-one, as well as phenoxyethanol.

[0125] [Surfactants] The surface treatment composition according to this embodiment may contain surfactants as needed. By including surfactants in the surface treatment composition, haze on the surface of the object to be treated can be better reduced. Any anionic, cationic, nonionic, or amphoteric surfactant can be used. Usually, anionic or nonionic surfactants are preferred. Nonionic surfactants are more preferred from the viewpoint of low foaming and ease of pH adjustment. Surfactants can be used alone or in combination of two or more.

[0126] Examples of nonionic surfactants include nonionic surfactants containing a polyoxyalkylene structure. Specific examples of nonionic surfactants containing a polyoxyalkylene structure include polyoxyalkylene structure-containing polymers such as block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, oxyalkylene polymers such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polytetramethylene glycol; polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, and polyoxyethylene propyl ether. Polyoxyalkylene alkyl ethers (preferably polyoxyethylene alkyl ethers) such as oxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, and polyoxyethylene oleyl ether; polyoxyalkylene alkylphenyl ethers (preferably polyoxyethylene alkylphenyl ethers) such as polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, and polyoxyethylene styrene phenyl ether; polyoxyalkylene alkylamines (preferably polyoxyethylene alkylamines) such as polyoxyethylene laurylamine, polyoxyethylene stearylamine, and polyoxyethylene oleylamine;Examples include polyoxyalkylene fatty acid esters (preferably polyoxyethylene fatty acid esters) such as polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, and polyoxyethylene dioleate; polyoxyalkylene sorbitan fatty acid esters (preferably polyoxyethylene sorbitan fatty acid esters) such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate; and polyoxyalkylene derivatives such as polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil. Among these, preferred surfactants include block copolymers of EO and PO (especially PEO-PPO-PEO type triblock copolymers), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ethers).

[0127] The weight-average molecular weight (Mw) of a surfactant is typically less than 5,000, preferably 4,000 or less (e.g., 3,000 or less) and more preferably 2,000 or less from the viewpoint of filterability and residue reduction. Furthermore, from the viewpoint of surface activity, the weight-average molecular weight of a surfactant is usually appropriate to be 200 or more, and from the viewpoint of haze reduction effect, it is preferably 250 or more (e.g., 300 or more). A more preferable range for the weight-average molecular weight of a surfactant may also vary depending on the type of surfactant. For example, when using polyoxyethylene alkyl ether as the surfactant, the weight-average molecular weight of the surfactant is preferably 1,500 or less, and may be 1,000 or less (e.g., 500 or less). The weight-average molecular weight of a surfactant can be calculated from a value based on gel permeation chromatography (GPC) (water-based, polyethylene glycol equivalent), or from a molecular weight calculated from a chemical formula. The GPC measurement conditions can be the same as those for water-soluble polymers containing hydroxyl groups described above.

[0128] If the surface treatment composition according to this embodiment contains a surfactant, there are no particular restrictions on its content as long as it does not significantly impair the effects of the present invention. Generally, from the viewpoint of reducing residue, it is appropriate to have a surfactant content of 20 parts by mass or less per 100 parts by mass of abrasive grains, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less (for example, 8 parts by mass or less). From the viewpoint of better demonstrating the effects of the surfactant, a surfactant content of 0.001 parts by mass or more per 100 parts by mass of abrasive grains is appropriate, preferably 0.005 parts by mass or more, and may also be 0.01 parts by mass or more, or 0.05 parts by mass or more. Note that when two or more surfactants are used, the above content refers to their total amount.

[0129] [Oxidizing Agent] In some embodiments of this model, the surface treatment composition preferably contains substantially no oxidizing agent. This is because if an oxidizing agent is included in the surface treatment composition, the surface of the object to be treated (silicon wafer) will be oxidized and an oxide film will be formed, which will increase the required surface treatment time. A specific example of an oxidizing agent is hydrogen peroxide (H ２O ２ Examples include sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate. It should be noted that "substantially free of oxidizing agents" in a surface treatment composition means that it does not intentionally contain oxidizing agents. Therefore, a surface treatment composition that inevitably contains trace amounts of oxidizing agents (for example, a molar concentration of oxidizing agents in the surface treatment composition of 0.001 mol / L or less, preferably 0.0005 mol / L or less, more preferably 0.0001 mol / L or less, even more preferably 0.00005 mol / L or less, and particularly preferably 0.00001 mol / L or less) due to raw materials or manufacturing methods may be included in the concept of a surface treatment composition that substantially does not contain oxidizing agents as defined herein.

[0130] [Method for Manufacturing Surface Treatment Compositions] The method for manufacturing surface treatment compositions according to some embodiments of this model is not particularly limited. For example, a boron-containing compound; a water-soluble polymer; a basic compound; and other components added as needed, such as abrasive particles and chelating agents, can be added to water all at once or sequentially, and stirred in the water.

[0131] [Form of Surface Treatment Composition, etc.] The surface treatment compositions according to some embodiments of this embodiment may be one-component or multi-component, consisting of two or more components. Furthermore, the surface treatment compositions described above may be used as is for surface treatment, or the concentrated solution of the surface treatment composition may be diluted by adding water, or, in the case of a multi-component surface treatment composition, by diluting it with an aqueous solution containing water and some of the constituent components before use. For example, the concentrated solution of the surface treatment composition can be stored or transported, and then diluted to prepare the surface treatment composition at the time of use. Thus, according to the present invention, a concentrated solution of the surface treatment composition according to this embodiment is also provided (the surface treatment composition according to this embodiment may be in the form of a concentrated solution).

[0132] Concentrated surface treatment compositions offer advantages in terms of convenience and cost reduction during manufacturing, distribution, and storage. The concentration ratio can be, for example, between 2 and 100 times in volume, and is usually between 5 and 50 times. The concentration ratio (concentration ratio when the surface treatment composition is in the form of a concentrated liquid) of a surface treatment composition (concentrated liquid) according to one preferred embodiment is between 8 and 40 times, for example, between 10 and 30 times.

[0133] [Subject to Surface Treatment] The surface treatment composition according to this embodiment is applied to the polishing (pre-polishing or finish polishing) or rinsing (rinse polishing) of silicon wafers (substrates having a surface made of silicon single crystals). In other words, the subject of surface treatment of the surface treatment composition according to this embodiment is a silicon wafer. The surface treatment composition according to this embodiment is applied to a polishing composition for pre-polishing and / or finish polishing of silicon wafers, and to a rinsing composition for rinse polishing.

[0134] The silicon wafer surface-treated using the surface treatment composition according to this embodiment may be p-type or n-type. Furthermore, there are no particular restrictions on the crystal orientation of the silicon wafer, and it may be any of <100>, <110>, or <111>.

[0135] The shape of the object to be surface treated is not particularly limited. According to one embodiment, the surface treatment composition according to this embodiment can be preferably applied to the surface treatment of an object having a flat surface, such as a plate or a polyhedron.

[0136] [Surface Treatment Method] In other embodiments of the present invention, a surface treatment method is provided which includes surface treatment of a silicon wafer using the above-described surface treatment composition. For example, according to one embodiment, a surface treatment method is provided which includes the step of surface treatment of a silicon wafer using the above-described surface treatment composition.

[0137] Another embodiment of the present invention is a surface treatment method that includes one or more selected from the group consisting of (i) a pre-polishing treatment or a finish polishing treatment and (ii) a rinse polishing treatment. That is, the surface treatment according to this embodiment is performed by at least one treatment selected from the group consisting of pre-polishing treatment, finish polishing treatment and rinse polishing treatment.

[0138] The surface treatment composition according to this embodiment is suitably used for the final polishing of silicon wafers. When the surface treatment composition according to this embodiment is used for the final polishing of silicon wafers, the silicon wafer surface becomes hydrophilic during the final polishing, preventing particle adhesion to the silicon wafer. As a result, both defects and haze on the silicon wafer surface can be reduced, and a deterioration in the quality of the silicon wafer surface can be prevented. (i) and (ii) will be described below.

[0139] (i) Pre-polishing or finish polishing The surface treatment composition according to this embodiment is preferably used in pre-polishing or finish polishing. The surface treatment composition according to this embodiment is particularly preferably used in finish polishing.

[0140] As the polishing apparatus, a general polishing apparatus can be used that has a holder for holding a substrate or the like with the object to be surface treated, a motor with a changeable rotation speed, and a polishing platen to which a polishing pad (abrasive cloth) can be attached.

[0141] The polishing pads can be of any type, including general nonwoven fabric, polyurethane, and suede types, without any particular restrictions. Preferably, the polishing pads have grooves that allow the surface treatment composition to accumulate.

[0142] The polishing conditions are set appropriately depending on the stage of the polishing process in which the surface treatment composition is used.

[0143] In the pre-polishing and finish polishing processes, either a double-sided polishing device or a single-sided polishing device may be used. The rotation speed of the platen is usually between 5 rpm and 100 rpm, preferably between 10 rpm and 50 rpm. The head rotation speed (carrier rotation speed) is preferably between 5 rpm and 100 rpm, and more preferably between 10 rpm and 50 rpm. When using a double-sided polishing device, the rotation speeds of the upper and lower rotating platens may be the same or different.

[0144] The surface-treated object is usually pressed down by a surface plate. The pressure can be selected as appropriate, but in the preliminary polishing process, it is generally preferable to be around 3 kPa to 69 kPa (0.5 psi to 10 psi), and more preferably around 7 kPa to 52 kPa (1.0 psi to 7.5 psi).

[0145] The supply speed of the surface treatment composition can be appropriately selected according to the size of the surface plate, but considering economic efficiency, for the pre-polishing and finish polishing processes, it is generally preferable to have a supply speed of 0.03 L / min to 10 L / min, and more preferably 0.05 L / min to 5 L / min.

[0146] There are no particular restrictions on the holding temperature of the surface treatment composition in the polishing apparatus, but from the viewpoint of reducing defects and haze, it is generally preferable to keep it between 15°C and 40°C, and more preferably between 18°C ​​and 25°C.

[0147] The above polishing conditions (settings for the polishing device) are merely examples, and the settings may be changed outside of the above range as appropriate. Such conditions can be set appropriately by those skilled in the art.

[0148] (ii) Rinse polishing The surface treatment composition according to this embodiment is suitably used in rinse polishing. Rinse polishing is performed on a polishing platen with a polishing pad attached, after the final polishing (finish polishing) of the object to be treated, for the purpose of removing impurities (defects) from the surface of the object to be treated. At this time, rinse polishing is performed by bringing the surface treatment composition according to this embodiment into direct contact with the object to be treated. As a result, impurities (defects) on the surface of the object to be treated are removed by the frictional force (physical action) of the polishing pad and the chemical action of the surface treatment composition.

[0149] Specifically, the rinse polishing process can be performed by placing the surface of the object to be treated after the polishing process on the polishing platen of a polishing machine, bringing the polishing pad into contact with the object to be treated, and supplying a surface treatment composition (rinse polishing composition) to the contact area while sliding the object and the polishing pad relative to each other.

[0150] There are no particular restrictions on the processing conditions, but for example, the pressure between the surface-treated object and the polishing pad is preferably 0.5 psi to 10 psi (0.003 MPa to 0.069 MPa). The head rotation speed (carrier rotation speed) is preferably 10 rpm to 100 rpm. The polishing platen rotation speed is preferably 10 rpm to 500 rpm. There are no restrictions on the flow rate, but it is preferable that the surface of the surface-treated object is covered with the surface treatment composition, for example, 10 mL / min to 5000 mL / min. The surface treatment time is also not particularly limited, but it is preferably 5 seconds to 300 seconds. In this invention, since the increase in the number of defects is suppressed even with long surface treatment times, the surface treatment time is preferably 20 seconds or more, more preferably 30 seconds or more, and even more preferably 45 seconds or more. The upper limit of the surface treatment time is usually within 10 minutes.

[0151] The temperature of the surface treatment composition during the rinse polishing process is not particularly limited and is usually at room temperature (25°C), but it may be heated to approximately 40°C to 70°C, as long as it does not impair performance.

[0152] The rinse polishing process can be carried out using either a single-sided polishing device or a double-sided polishing device. Furthermore, it is preferable that the polishing device includes a nozzle for discharging a rinse polishing composition in addition to a nozzle for discharging a polishing composition. The operating conditions of the polishing device during the rinse polishing process are not particularly limited and can be set appropriately by those skilled in the art.

[0153] While embodiments of the present invention have been described in detail, these are descriptive and illustrative, and not limiting, and it is clear that the scope of the present invention should be interpreted by the appended claims.

[0154] The present invention encompasses the following embodiments and forms.

[0155] [1] A surface treatment composition for use in surface treatment of silicon wafers, comprising a boron-containing compound, a water-soluble polymer, a basic compound, and water.

[0156] [2] The surface treatment composition according to [1], further comprising abrasive grains.

[0157] [3] The surface treatment composition according to [2] above, wherein the mass ratio of the boron-containing compound to the abrasive grains is less than 0.1 (preferably 0.05 or less).

[0158] [4] The surface treatment composition according to any one of [1] to [3] above, wherein the content of the boron-containing compound is less than 0.1% by mass with respect to the total mass of the composition.

[0159] [5] The surface treatment composition according to any one of [1] to [4] above, wherein the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is less than 0.004.

[0160] [6] The surface treatment composition according to any one of [1] to [5] above, wherein the boron-containing compound is boric acid.

[0161] [7] The water-soluble polymer is a surface treatment composition according to any one of [1] to [6] above, wherein the water-soluble polymer includes a polyvinyl alcohol-based polymer.

[0162] [8] The surface treatment composition according to any one of [1] to [7] above, wherein the content of the water-soluble polymer is 0.01% by mass or less with respect to the total mass of the composition.

[0163] [9] A concentrated solution of any of the surface treatment compositions described in [1] to [8] above.

[0164]

[10] A surface treatment method comprising the step of surface treating a silicon wafer using any of the surface treatment compositions described in [1] to [8] above.

[0165] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "mass percent" and "parts by mass," respectively.

[0166] [Average Primary Particle Diameter of Abrasive Grains] The average primary particle diameter of abrasive grains was calculated from the specific surface area and density of the abrasive grains using the BET method. The specific surface area of ​​the abrasive grains using the BET method was measured using "Flow Sorb II 2300" (Micromerities).

[0167] [pH of Surface Treatment Composition] The pH of the surface treatment composition was measured using a glass electrode type hydrogen ion concentration indicator (model number: F-23, manufactured by Horiba, Ltd.). Three-point calibration was performed using standard buffer solutions: phthalate pH buffer pH: 4.01 (25°C), neutral phosphate pH buffer pH: 6.86 (25°C), and carbonate pH buffer pH: 10.01 (25°C). The glass electrode was then immersed in the surface treatment composition for at least two minutes. After the pH of the surface treatment composition stabilized, the pH of the surface treatment composition was measured.

[0168] [Raw materials for surface treatment compositions] The surface treatment compositions shown in Table 1 below were prepared using the following raw materials.

[0169] • Abrasive grains: Colloidal silica, average primary particle size: 25 nm • Water-soluble polymer (a) Polyvinyl alcohol (PVA): Unmodified, 99% saponification, weight-average molecular weight (Mw) 5.8 × 10 ４ (b) Poly-N-acryloylmorpholine (PACMO): weight-average molecular weight (Mw) 35 × 10 ４(c) Hydroxyethylcellulose (HEC): Weight-average molecular weight (Mw) 25 × 10 ４ • Surfactant: Polyoxyethylene decyl ether (ethylene oxide addition moles: 5) • Basic compound: Ammonia • Chelating agent: Ethylenediamine tetrakis (methylenephosphonic acid) (EDTPO) • Dispersion medium: Pure water.

[0170] [Preparation of Surface Treatment Compositions] (Examples 1-4 and Comparative Example 1) The final concentration was 0.17% by mass of abrasive grains; boric acid as the boron-containing compound at the concentration shown in Table 1; the above-mentioned PVA as the water-soluble polymer and 0.004% by mass of PACMO; 0.0001% by mass of polyoxyethylene decyl ether as the surfactant; 0.011% by mass of ammonia as the basic compound; and 0.003% by mass of EDTPO as the chelating agent. These were added to pure water, which was the dispersion medium, at room temperature (25°C), and stirred and mixed at room temperature (25°C) for 30 minutes to obtain the surface treatment compositions for Examples 1-4 and Comparative Example 1. Note that Comparative Example 1 did not contain any boron-containing compound.

[0171] The pH of each surface treatment composition obtained was 10.2. The particle size of the abrasive grains in each surface treatment composition was the same as that of the abrasive grains used. In Table 1, "-" indicates that the agent was not included.

[0172] (Example 5) The surface treatment composition of Example 5 was obtained by adding the following to pure water, which is the dispersion medium, at room temperature (25°C) and stirring for 30 minutes at room temperature (25°C) so that the final concentration was 0.17% by mass of abrasive grains; diboron trioxide as a boron-containing compound at the concentration shown in Table 1; the above PVA as a water-soluble polymer and 0.004% by mass of PACMO; 0.0001% by mass of polyoxyethylene decyl ether as a surfactant; 0.011% by mass of ammonia as a basic compound; and 0.003% by mass of EDTPO as a chelating agent.

[0173] The pH of the surface treatment composition obtained in Example 5 was 10.2. The particle size of the abrasive grains in the surface treatment composition of Example 5 was the same as the particle size of the abrasive grains used.

[0174] (Examples 6, 7 and Comparative Example 2) The surface treatment compositions for Examples 6, 7 and Comparative Example 2 were obtained by adding the following to pure water, which is the dispersion medium, at room temperature (25°C) and stirring for 30 minutes at room temperature (25°C) so that the final concentration was 0.17% by mass of abrasive grains; boric acid as the boron-containing compound at the concentration shown in Table 2; the above HEC as the water-soluble polymer at the concentration shown in Table 2; polyoxyethylene decyl ether as the surfactant at 0.0001% by mass; and ammonia as the basic compound. Note that Comparative Example 2 did not contain the boron-containing compound.

[0175] The pH of the surface treatment composition obtained in Example 6 was 10.1, and the pH of the surface treatment composition in Example 7 was 10.0. The particle size of the abrasive grains in each surface treatment composition was the same as the particle size of the abrasive grains used. In Table 2, "-" indicates that the agent is not included.

[0176] <Polishing (Surface Treatment)> The surface of the silicon wafer was subjected to secondary polishing under the following secondary polishing conditions, followed by finish polishing (surface treatment) using the surface treatment compositions of the Examples and Comparative Examples under the following finish polishing conditions, and then cleaning under the following cleaning conditions. Note that secondary polishing corresponds to preliminary polishing.

[0177] [Objects to be surface treated] ・Silicon wafer…Type: p-type COP-free / Crystal orientation: <100> / Size: 300 mm.

[0178] [Secondary Polishing Conditions] ・Polishing equipment: Single-wafer polishing machine manufactured by Okamoto Machine Tool Works, Ltd., model "PNX 332B" ・Polishing load: 20 kPa ・Plate rotation speed: 20 rpm ・Carrier rotation speed: 20 rpm ・Polishing pad: Nitta DuPont, product name "SUBA400" ・Polishing composition supply rate: 1 L / min (*flowing) ・Polishing composition temperature: 20°C ・Plate cooling water temperature: 20°C ・Polishing time: 2 minutes ・Polishing composition used in secondary polishing (composition): Abrasive grains (colloidal silica, average primary particle size 35 nm) 1.0 mass%, KOH 0.068 mass%, remainder water.

[0179] [Finishing Polishing Conditions] ・Polishing equipment: Single-wafer polishing machine manufactured by Okamoto Machine Tool Works, Ltd., model "PNX 332B" ・Polishing load: 10 kPa ・Plate rotation speed: 50 rpm ・Carrier rotation speed: 50 rpm ・Polishing pad: Product name "POLYPAS275NX" manufactured by Fujibo Ehime Co., Ltd. ・Surface treatment composition supply rate: 1.0 L / min (*flowing) ・Surface treatment composition temperature: 20°C ・Plate cooling water temperature: 20°C ・Polishing time: 4 minutes ・Surface treatment composition used for finishing polishing: Surface treatment compositions of the examples and comparative examples.

[0180] [Cleaning Conditions] After the secondary and finish polishing described above, the surface treatment object was washed with ozonated water for 1 minute, and then rinsed with deionized water to remove any remaining ozonated water. Subsequently, the surface treatment object was treated with NH ４ OH: H ２ O ２ The silicon wafer surface was scrubbed with a brush while applying a chemical solution of deionized water (DIW) = 2.7:1:396 (volume ratio), then ozonated water was applied, and finally, the wafer was cleaned with hydrofluoric acid solution. This ozonated water cleaning and hydrofluoric acid solution cleaning was considered one set, and this was repeated three times before the surface-treated object was dried.

[0181] <Surface Quality Evaluation> The surface of the silicon wafer after polishing under the above polishing conditions was evaluated using the following method.

[0182] [Evaluation of Haze on Silicon Wafer Surfaces] For evaluating the haze of polished silicon wafers, the value (DWO haze) measured using the dark-field wide oblique incidence channel (DW2O mode) with the surface roughness measuring device "SURFSCAN SP5" (manufactured by KLA Tencor) was used. A smaller DWO haze value indicates higher surface smoothness.

[0183] Haze measurements were performed on four silicon wafers, and the average value was calculated. The evaluation results for Examples 1-5 and Comparative Example 1 are shown in Table 1 below, and the evaluation results for Examples 6, 7 and Comparative Example 2 are shown in Table 2 below. In Table 1, the LPD-N values ​​are shown as relative values ​​with the haze (DWO) value of Comparative Example 1 set to 100%, and in Table 2, the LPD-N values ​​are shown as relative values ​​with the haze (DWO) value of Comparative Example 2 set to 100%. Furthermore, the haze was evaluated based on the evaluation criteria below for these relative values, and the results are shown in Tables 1 and 2, respectively.

[0184] Hays Evaluation Criteria: A...Less than 100% compared to Comparative Example 1 or Comparative Example 2; B...100% or more and 105% or less compared to Comparative Example 1 or Comparative Example 2; C...More than 105% compared to Comparative Example 1 or Comparative Example 2.

[0185] [Evaluation of defects (LPD-N) on the silicon wafer surface] The number of LPD-Ns (Light Point Defect Non-cleanable) present on the surface (polished surface) of the silicon wafer obtained by the above polishing was measured using a wafer inspection device, product name "SURFSCAN SP5" (manufactured by KLA Tencor), in the DCO mode of the device.

[0186] The evaluation results for Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below, and the evaluation results for Examples 6 and 7 and Comparative Example 2 are shown in Table 2 below. In Table 1, the numerical values ​​for defects (LPD-N) are shown as relative values ​​with the LPD-N value of Comparative Example 1 set to 100%, and in Table 2, the numerical values ​​for defects (LPD-N) are shown as relative values ​​with the LPD-N value of Comparative Example 2 set to 100%. Furthermore, the defects were evaluated based on the evaluation criteria below, and the results are shown in Tables 1 and 2 below.

[0187] 《Defect Evaluation Criteria》 A: 80% or less compared to Comparative Example 1 or Comparative Example 2; B: Greater than 80% but less than 100% compared to Comparative Example 1 or Comparative Example 2; C: 100% or more compared to Comparative Example 1 or Comparative Example 2.

[0188]

[0189]

[0190] As is clear from Tables 1 and 2 above, the surface treatment compositions of the examples can significantly reduce defects and haze on the silicon wafer surface after surface treatment. On the other hand, the surface treatment compositions of the comparative examples are inferior in terms of reducing defects and haze on the silicon wafer surface after surface treatment.

[0191] Therefore, the surface treatment composition according to this embodiment can significantly reduce defects and haze on the silicon wafer surface after surface treatment.

[0192] This application is based on Japanese Patent Application No. 2024-168071, filed on 27 September 2024, the disclosures thereof being incorporated herein by reference in their entirety.

Claims

1. A surface treatment composition for use in surface treatment of silicon wafers, comprising a boron-containing compound, a water-soluble polymer, a basic compound, and water.

2. The surface treatment composition according to claim 1, further comprising abrasive particles.

3. The surface treatment composition according to claim 2, wherein the mass ratio of the boron-containing compound to the abrasive grains (mass of boron-containing compound / mass of abrasive grains) is less than 0.

1.

4. The surface treatment composition according to claim 1 or 2, wherein the content of the boron-containing compound is less than 0.1% by mass of the total mass of the composition.

5. The surface treatment composition according to claim 1 or 2, wherein the mass ratio of the boron-containing compound to the water-soluble polymer (mass of the boron-containing compound / mass of the water-soluble polymer) is less than 0.

004.

6. The surface treatment composition according to claim 1 or 2, wherein the boron-containing compound is boric acid.

7. The surface treatment composition according to claim 1 or 2, wherein the water-soluble polymer comprises a polyvinyl alcohol-based polymer.

8. The surface treatment composition according to claim 1 or 2, wherein the content of the water-soluble polymer is 0.01% by mass or less with respect to the total mass of the composition.

9. A concentrated solution of the surface treatment composition according to claim 1 or 2.

10. A surface treatment method comprising the step of surface treating a silicon wafer using the surface treatment composition according to claim 1 or 2.

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