Surface treatment composition, method for producing surface treatment composition, surface treatment method, and method for producing semiconductor substrate

Abstract

To provide means capable of sufficiently removing organic residue present on the surface of a polished object to be polished containing silicon nitride or polysilicon.SOLUTION: A surface treatment composition includes a polymer having a structural unit represented by chemical formula (1), at least one of an anionic surfactant and a nonionic surfactant, and water, and is used for treating the surface of a polished object to be polished. In the formula (1), R1 is a hydrocarbon group having 1 to 5 carbon atoms, and R2 is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a surface treatment composition, a method for producing the surface treatment composition, a surface treatment method, and a method for producing a semiconductor substrate. [Background technology]

[0002] In recent years, with the trend toward multi-layer wiring on the surface of semiconductor substrates, a so-called chemical mechanical polishing (CMP) technique is used to polish and flatten semiconductor substrates when manufacturing semiconductor devices. CMP is a method for flattening the surface of an object to be polished (object to be polished) such as a semiconductor substrate using a polishing composition (slurry) containing abrasive grains such as silica, alumina, ceria, etc., an anticorrosive agent, a surfactant, etc. The object to be polished (object to be polished) is silicon, polysilicon, silicon oxide film (silicon oxide), silicon nitride, wiring, plugs, etc. made of metal, etc.

[0003] A large amount of impurities (defects) remain on the surface of a semiconductor substrate after the CMP process. The impurities include organic matter such as abrasive grains, metals, anticorrosives, and surfactants derived from the polishing composition used in CMP, silicon-containing materials that are the objects to be polished, silicon-containing materials and metals generated by polishing metal wiring, plugs, etc., and further organic matter such as pad debris generated from various pads, etc.

[0004] If the semiconductor substrate surface is contaminated by these impurities, it may adversely affect the electrical characteristics of the semiconductor and reduce the reliability of the semiconductor device. Therefore, it is desirable to introduce a cleaning process after the CMP process to remove these impurities from the semiconductor substrate surface. An example of a cleaning liquid (cleaning composition) used in such a cleaning step is disclosed in Patent Document 1. Patent Document 1 discloses a slurry composition for chemical mechanical polishing, which contains water, polishing abrasive grains, and one or more water-soluble polymers containing a polyvinyl alcohol structural unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-74678 A Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to further reduce defects when cleaning a polished object. Here, the present inventors have investigated the relationship between the type of polished object and the type of defects, and have found that organic residues tend to remain on the surface of a polished object (e.g., a polished semiconductor substrate) containing silicon nitride or polysilicon, and that such organic residues can cause damage to semiconductor devices. The present invention has been made in consideration of the above problems, and has an object to provide a means capable of sufficiently removing organic residues present on the surface of a polished object containing silicon nitride or polysilicon. [Means for solving the problem]

[0007] In view of the above problems, the present inventors have conducted intensive research and have found that by using a surface treatment composition containing a polymer having a structural unit represented by the formula (1) of the following [Chemical Formula 1], at least one of an anionic surfactant and a nonionic surfactant, and water, organic residues present on the surface of a polished object containing silicon nitride or polysilicon can be sufficiently removed, and thus the present invention has been completed.

[0008] [ka] In the above formula (1), R1 is a hydrocarbon group having 1 to 5 carbon atoms, and R2 is a hydrogen atom or a carbon atom. It is a hydrocarbon group having a number of 1 to 3. Effect of the Invention

[0009] According to the present invention, there is provided a means capable of sufficiently removing organic residues present on the surface of a polished object containing silicon nitride or polysilicon. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below. Note that the present invention is not limited to the following embodiments. In addition, in this specification, the notation "(meth)acrylic" in the specific names of compounds represents "acrylic" and "methacrylic", and "(meth)acrylate" represents "acrylate" and "methacrylate".

[0011] [Organic residue] In this specification, the organic residue refers to components of foreign matter adhering to the surface of a polished object, such as organic substances such as organic low molecular weight compounds and high molecular weight compounds, and organic salts. Examples of organic residues adhering to the object to be cleaned include pad waste generated from a pad used in the polishing step described below or the rinse polishing step which may be optionally provided, or components derived from additives contained in the polishing composition used in the polishing step or the rinse polishing composition used in the rinse polishing step. Since organic residues and other foreign matter differ significantly in color and shape, whether or not a foreign matter is an organic residue can be determined by visual inspection using a SEM, and, if necessary, by elemental analysis using an energy dispersive X-ray analyzer (EDX).

[0012] [Polished object] In this specification, the term "polished object" refers to an object that has been polished in a polishing step. The polishing step is not particularly limited, but is preferably a CMP step. The surface treatment composition according to one embodiment of the present invention is preferably used for reducing organic residues remaining on the surface of a polished object (hereinafter, also simply referred to as an "object to be cleaned") containing silicon nitride (hereinafter, also simply referred to as "SiN") or polysilicon (hereinafter, also simply referred to as "Poly-Si").

[0013] The polished object is preferably a polished semiconductor substrate, more preferably a semiconductor substrate after CMP, because organic residues in particular can cause damage to semiconductor devices, and therefore, when the polished object is a polished semiconductor substrate, the cleaning process for the semiconductor substrate must be capable of removing as much organic residue as possible.

[0014] Examples of polished objects containing silicon nitride or polysilicon include, but are not limited to, polished objects made of silicon nitride and polysilicon alone, and polished objects in which materials other than silicon nitride or polysilicon are exposed on the surface. Examples of the former include silicon nitride substrates or polysilicon substrates, which are semiconductor substrates. Examples of the latter include materials other than silicon nitride or polysilicon, which are not limited to, but include tungsten. Specific examples of such polished objects include polished semiconductor substrates having a structure in which a silicon nitride film or polysilicon film is formed on tungsten, and polished semiconductor substrates having a structure in which the tungsten portion, the silicon nitride film, and the polysilicon film are all exposed. Here, in terms of the effects achieved by the present invention, it is preferable that the polished object according to one embodiment of the present invention contains polysilicon.

[0015] [Surface treatment composition] One embodiment of the present invention is a surface treatment composition that contains a polymer having a structural unit represented by formula (1) of the following [Chemical Formula 2] and water, and is used to treat the surface of a polished object.

[0016] [ka]

[0017] In the above formula (1), R1 is a hydrocarbon group having 1 to 5 carbon atoms, and R2 is a hydrogen atom or a carbon atom. It is a hydrocarbon group having a number of 1 to 3. The surface treatment composition according to one embodiment of the present invention is particularly preferably used as an organic residue reducer for selectively removing organic residues in a surface treatment process. The present inventors presume that the mechanism by which the above-mentioned problems are solved by the present invention is as follows: The surface treatment composition has a function of removing or facilitating the removal of foreign matter on the surface of a polished object to be polished as a result of chemical interaction between each component contained in the surface treatment composition and the surface and foreign matter of the polished object to be polished.

[0018] A polymer having a constitutional unit represented by formula (1) can physically adsorb to a hydrophobic wafer surface, thereby changing the surface to hydrophilic. Organic residues adhering to the wafer are lifted up during processing, and then the polymer is adsorbed to the wafer. As a result, the layer formed by the polymer functions as a layer preventing re-adhesion of organic residues, and thus organic residues can be easily removed from the wafer. For example, the polymer hydrophilizes polysilicon (Poly-Si) that appears on the wafer surface, and removes organic residues. It should be noted that the above mechanism is based on speculation, and whether it is correct or not does not affect the technical scope of the present invention.

[0019] Each component contained in the surface treatment composition will be described below. [Polymer having a structural unit represented by formula (1)] Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R1 in the above formula (1) include alkyl groups such as methyl, ethyl, and propyl groups; alkenyl groups such as ethenyl and propenyl groups; alkynyl groups such as ethynyl and propynyl groups; and cycloalkyl groups such as cyclopentyl groups. Among these, alkyl and alkynyl groups are preferred, and hydrocarbon groups having 1 to 3 carbon atoms are also preferred. As R1, methyl, ethyl, and ethenyl groups (vinyl groups) are more preferred, and methyl and ethyl groups are even more preferred.

[0020] Examples of the hydrocarbon group having 1 to 3 carbon atoms represented by R2 in the above formula (1) include those having 1 to 3 carbon atoms among those exemplified as the hydrocarbon group having 1 to 5 carbon atoms represented by R1. R2 is preferably a hydrogen atom or a methyl group. Examples of the unsaturated monomer that gives the above-mentioned structural unit include N-vinylacetamide, N-vinylpropionamide, N-vinylbutylamide, etc., and N-vinylacetamide and N-vinylpropionamide are preferred. The above-mentioned unsaturated monomers can be used alone or in combination of two or more.

[0021] The weight average molecular weight (Mw) of the polymer is usually 30,000 or more and 1,000,000 or less, preferably 50,000 or more and 900,000 or less, and more preferably 50,000 or more and 100,000 or less. By setting the weight average molecular weight (Mw) of the polymer within the above range, organic residues on the polished object surface can be more effectively reduced. The lower limit of the content of the polymer having the structural unit represented by formula (1) (the total amount when two or more types are used) is not particularly limited, but is preferably 0.02 mass% or more based on the total amount of the surface treatment composition. If the content is 0.02 mass% or more, organic residues on the polished object surface can be more effectively reduced.

[0022] From the same viewpoint, the lower limit of the content of the polymer having the structural unit represented by formula (1) is more preferably 0.03 mass% or more, and even more preferably 0.05 mass% or more, based on the total amount of the surface treatment composition. On the other hand, the upper limit of the content of the polymer having the structural unit represented by formula (1) is preferably 1 mass% or less, based on the total amount of the surface treatment composition. If the content is 1 mass% or less, it becomes easy to remove the polymer having the structural unit represented by formula (1) itself after the surface treatment. From the same viewpoint, the upper limit of the content of the polymer having the structural unit represented by formula (1) is more preferably 0.7 mass% or less, and even more preferably 0.5 mass% or less, based on the total amount of the surface treatment composition.

[0023] The content of the structural unit in the polymer is preferably 30 mol% or more and 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, and even more preferably 70 mol% or more and 100 mol% or less. By setting the content of the structural unit within the above range, organic residue on the polished object surface can be more effectively reduced.

[0024] [Water-soluble polymers with glycerin-derived structural units] The surface treatment composition according to one embodiment of the present invention may contain a water-soluble polymer having a structural unit derived from glycerin. Preferred examples of the water-soluble polymer having a structural unit derived from glycerin include at least one selected from the group consisting of polyglycerin (see formula (2) below), alkyl (C10-14) esters of polyglycerin, polyglycerin alkyl (C10-14) ethers, ethylene oxide-modified polyglycerin, sulfonic acid-modified polyglycerin (see, for example, formulas (3) and (4) below), and phosphonic acid-modified polyglycerin (see, for example, formulas (5) and (6) below).

[0025] [ka]

[0026] In the above formulas (2) to (6), m and n each independently represent the number of repeating units, and M in the above formulas (3) to (6) each independently represents a hydrogen atom, Na, K, or NH 4 Represents +. In addition, the multiple M's in the above formulas (3) to (6) may be the same or different from each other. For example, all of the n M's in the above formula (3) may be Na, or may be a hydrogen atom, Na, K, or NH 4 For example, all of the m M's in the above formula (4) may be Na, or may be a hydrogen atom, Na, K, or NH 4 A combination of two or more of the above may be used.

[0027] The above-mentioned water-soluble polymers having a structural unit derived from glycerin can be used alone or in combination of two or more kinds. The content (concentration) of the water-soluble polymer having a structural unit derived from glycerin (the total amount when two or more types are used) is not particularly limited, but is preferably 0.02 mass% or more relative to the total amount of the surface treatment composition. When the content is 0.02% by mass or more, the effects of the present invention are improved.

[0028] From the same viewpoint, the content (concentration) of the water-soluble polymer having a glycerin-derived structural unit is more preferably 0.03% by mass or more, and even more preferably 0.05% by mass or more, based on the total amount of the surface treatment composition. The content (concentration) of the water-soluble polymer having a glycerin-derived structural unit is preferably 1% by mass or less, based on the total amount of the surface treatment composition. When the content (concentration) of the water-soluble polymer having a glycerin-derived structural unit is 1% by mass or less, it becomes easy to remove the water-soluble polymer having a glycerin-derived structural unit itself after the surface treatment. From the same viewpoint, the content (concentration) of the water-soluble polymer having a glycerin-derived structural unit is more preferably 0.7% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the surface treatment composition.

[0029] The weight-average molecular weight (Mw) of the water-soluble polymer having a glycerin-derived structural unit is preferably 1,000 or more. When the weight-average molecular weight is 1,000 or more, the effect of removing foreign matter is further improved. This is presumably because the water-soluble polymer having a glycerin-derived structural unit has better covering properties when covering the object to be cleaned or foreign matter, and the action of removing foreign matter from the surface of the object to be cleaned or the action of preventing foreign matter from reattaching to the surface of the object to be cleaned is further improved. From the same viewpoint, the weight-average molecular weight is more preferably 3,000 or more, and even more preferably 8,000 or more. In addition, the upper limit of the weight-average molecular weight of the water-soluble polymer having a glycerin-derived structural unit is not particularly limited, but is preferably 1,000,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less. The weight average molecular weight can be determined by gel permeation chromatography (GPC) using a GPC device (Shimadzu Corporation, Model: Prominence + ELSD detector (ELSD-LTII)) or the like in terms of polyethylene glycol, and specifically, can be measured by the method described in the Examples. The water-soluble polymer having a constitutional unit derived from glycerin may be a commercially available product or a synthetic product. In the case of synthesis, the production method is not particularly limited, and a known polymerization method can be used.

[0030] [Dispersion medium] The surface treatment composition according to one embodiment of the present invention essentially contains water as a dispersion medium (solvent). The dispersion medium has the function of dispersing or dissolving each component. The dispersion medium is preferably only water. The dispersion medium may be a mixed solvent of water and an organic solvent for dispersing or dissolving each component. In this case, examples of the organic solvent used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, propylene glycol, and the like, which are organic solvents miscible with water. These organic solvents may be used without being mixed with water, and then each component may be dispersed or dissolved, and then mixed with water. These organic solvents may be used alone or in combination of two or more.

[0031] From the viewpoint of preventing contamination of the object to be cleaned and inhibiting the action of other components, it is preferable that the water contains as few impurities as possible. For example, water having a total transition metal ion content of 100 ppb or less is preferable. Here, the purity of the water can be increased by, for example, removing impurity ions using ion exchange resin, removing foreign matter using a filter, distillation, or other operations. Specifically, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, or the like as the water.

[0032] [Surfactants] The surface treatment composition according to one embodiment of the present invention contains at least one of an anionic surfactant and a nonionic surfactant (i.e., an anionic surfactant, a nonionic surfactant, or both). The anionic surfactant, the nonionic surfactant, or a mixture thereof contributes to the removal of foreign matter by the surface treatment composition. For example, the anionic surfactant and the nonionic surfactant disperse and remove particles and organic residues attached to silicon nitride (SiN), respectively. Therefore, the surface treatment composition containing at least one of the anionic surfactant and the nonionic surfactant can sufficiently remove foreign matter (impurities including organic residues, etc.) remaining on the surface of the polished object during surface treatment (cleaning, etc.) of the polished object.

[0033] The number of carbon atoms (C) in the hydrophobic portion of the anionic surfactant is preferably 8 or more and 12 or less. When the number of carbon atoms in the hydrophobic portion of the anionic surfactant is 8 or more and 12 or less (i.e., the length of the alkyl chain in the hydrophobic portion is 8 to 12 carbon atoms), the anionic surfactant is easily dissolved in water, and the cleaning performance of the surface treatment composition can be maintained at a high level. When the number of carbon atoms in the hydrophobic portion is 15 or more, the anionic surfactant becomes difficult to dissolve in water, and the function as a surfactant tends to decrease. Note that ammonium dodecyl sulfate described in the examples below is an example of an anionic surfactant, and the number of carbon atoms in the hydrophobic portion is 12.

[0034] Similarly, the number of carbon atoms (C) in the hydrophobic portion of the nonionic surfactant is preferably 8 or more and 12 or less. When the number of carbon atoms in the hydrophobic portion of the nonionic surfactant is 8 or more and 12 or less (i.e., the length of the alkyl chain in the hydrophobic portion is 8 to 12 carbon atoms), the nonionic surfactant is easily dissolved in water, and the cleaning performance of the surface treatment composition can be maintained at a high level. When the number of carbon atoms in the hydrophobic portion is 15 or more, the nonionic surfactant becomes difficult to dissolve in water, and the function as a surfactant tends to decrease. Note that polyglycerin lauryl ether described in the examples below is an example of a nonionic surfactant, and the number of carbon atoms in the hydrophobic portion is 12.

[0035] <Anionic surfactants> Examples of anionic surfactants include polyoxyethylene alkyl ether acetate, polyoxyethylene alkyl sulfate, alkyl sulfate, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate, alkyl benzene sulfonate, alkyl phosphate, polyoxyethylene alkyl phosphate, polyoxyethylene sulfosuccinate, alkyl sulfosuccinate, alkyl naphthalene sulfonate, alkyl diphenyl ether disulfonate, and salts thereof. Among these, alkyl sulfate, polyoxyethylene alkyl sulfate, polyoxyethylene alkyl ether sulfate, alkyl ether sulfate, alkyl benzene sulfonate, polyoxyethylene sulfosuccinate, and alkyl sulfosuccinate are preferred. Ammonium dodecyl sulfate described in the examples below is classified as an alkyl sulfate. Each of the above examples of anionic surfactants may be used alone or in combination of two or more.

[0036] <Nonionic surfactant> Examples of nonionic surfactants include alkyl betaines, alkyl amine oxides, polyoxyethylene alkyl ethers, polyoxyalkylene alkyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, and alkyl alkanolamides. Another example of nonionic surfactants includes polyglycerin-based surfactants. Examples of polyglycerin-based surfactants include polyglycerin lauryl esters and polyglycerin lauryl ethers. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyalkylene alkyl ethers, and polyglycerin-based surfactants, and more preferably polyglycerin lauryl esters and polyglycerin lauryl ethers. Each of the above-mentioned examples of nonionic surfactants may be used alone or in combination of two or more.

[0037] [pH] The surface treatment composition according to one embodiment of the present invention has a pH value of 7 or more, preferably 7.5 or more. The surface treatment composition according to one embodiment of the present invention has a pH value of 12 or less, preferably 11 or less, more preferably 10 or less. When the surface treatment composition has a pH of 7 or more, when the surface treatment composition is used on foreign matter or an object to be cleaned that has the property of being negatively charged, the surface of the object to be cleaned or the surface of the foreign matter can be negatively charged, and a high foreign matter removal effect can be obtained due to electrostatic repulsion.

[0038] The pH value of the surface treatment composition can be confirmed using a pH meter (manufactured by Horiba, Ltd., product name: LAQUA (registered trademark)). When adjusting the pH value, it is desirable not to add, as much as possible, components other than the surface treatment composition according to one embodiment of the present invention because they may cause foreign matters. Therefore, the surface treatment composition is preferably prepared with only at least one of a water-soluble polymer having a structural unit derived from the above glycerin, water, an anionic surfactant, and a nonionic surfactant. However, when it is difficult to obtain a desired pH with only these, adjustment may be made using an additive (for example, a pH adjuster described below) that can be arbitrarily added within a range that does not inhibit the effects of the present invention.

[0039] <pH adjuster> The pH regulator may be either an acid or an alkali, and may be either an inorganic compound or an organic compound. In the present specification, the above anionic surfactant is treated as different from the acid as the pH adjuster described here. The acid is mainly added for the purpose of adjusting the pH of the surface treatment composition.

[0040] Specific examples of the acid as the pH adjuster include inorganic acids and organic acids such as carboxylic acids and organic sulfates. Specific examples of the inorganic acids include sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, phosphoric acid, etc. As the pH adjuster, it is preferable to use an inorganic acid, and among them, phosphoric acid-based inorganic acids are more preferable. Organic acids include carboxylic acids, organic sulfates, and organic phosphonic acids. Specific examples of the carboxylic acids include 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, etc. Further, specific examples of the organic sulfates include methanesulfonic acid, ethanesulfonic acid, isethionic acid, etc. Specific examples of the organic phosphonic acids include methanephosphonic acid, etidronic acid, phenylphosphonic acid, etc.

[0041] These acids may be used alone or in combination of two or more. As the organic acid, it is preferable to use a carboxylic acid or a phosphonic acid. These acids may be included in the surface treatment composition as a pH adjuster, or may be included as an additive for improving the polishing rate, or may be a combination of these.

[0042] Specific examples of bases as pH adjusters include alkali metal hydroxides or their salts, alkaline earth metal hydroxides or their salts, quaternary ammonium hydroxides or their salts, ammonia, amines, etc. Specific examples of alkali metals include potassium, sodium, etc. Specific examples of alkaline earth metals include calcium, strontium, etc. Specific examples of salts include carbonates, hydrogen carbonates, sulfates, acetates, etc. Specific examples of quaternary ammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium, etc.

[0043] The quaternary ammonium hydroxide compound includes quaternary ammonium hydroxide or a salt thereof, and specific examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc. Furthermore, specific examples of the amine 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, etc.

[0044] These bases may be used alone or in combination of two or more. Among these bases, ammonia, ammonium salts, alkali metal hydroxides, alkali metal salts, quaternary ammonium hydroxide compounds, and amines are preferred, and ammonia, potassium compounds, sodium hydroxide, quaternary ammonium hydroxide compounds, ammonium hydrogen carbonate, ammonium carbonate, sodium hydrogen carbonate, and sodium carbonate are more preferred. In addition, it is more preferred that the surface treatment composition contains a potassium compound as a base from the viewpoint of preventing metal contamination. Examples of potassium compounds include potassium hydroxides or potassium salts, and specific examples include potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium sulfate, potassium acetate, and potassium chloride.

[0045] [Chelating agents] The surface treatment composition according to one embodiment of the present invention may contain a chelating agent in any ratio as necessary within a range that does not impair the effects of the present invention. For example, the chelating agent has at least one of a phosphonic acid group and a carboxylic acid group. That is, the chelating agent may have only a phosphonic acid group, may have only a carboxylic acid group, or may have both a phosphonic acid group and a carboxylic acid group.

[0046] The chelating agent forms complex ions with metal impurities that may be contained in the surface treatment composition and captures them, thereby suppressing contamination of the polished object by metal impurities. Examples of chelating agents having a phosphonic acid group (hereinafter also referred to as "phosphonic acid chelating agents") include 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), nitrilotris(methylenephosphonic acid) (ATMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), sodium hexametaphosphate, and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC). Examples of chelating agents having a carboxylic acid group (hereinafter also referred to as "carboxylic acid chelating agents") include triethylenetetraminehexaacetic acid (TTHA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N,N'-disuccinic acid (EDDS), succinic acid, glutaric acid, citric acid, and mercaptosuccinic acid.

[0047] Furthermore, the phosphonic acid-based chelating agent and the carboxylic acid-based chelating agent are not limited to those mentioned above, and may be, for example, the following examples. Examples of 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.Preferred among these are EDTPO, diethylenetriaminepenta(methylenephosphonic acid) and diethylenetriaminepentaacetic acid. Particularly preferred phosphonic acid chelating agents include EDTPO and diethylenetriaminepenta(methylenephosphonic acid). Examples of carboxylic acid chelating agents include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrilotriacetic acid, sodium nitrilotriacetate, ammonium nitrilotriacetate, hydroxyethylethylenediaminetriacetic acid, sodium hydroxyethylethylenediaminetriacetate, diethylenetriaminepentaacetic acid, sodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, and sodium triethylenetetraminehexaacetate. The chelating agents can be used alone or in combination of two or more.

[0048] [Other additives] The surface treatment composition according to one embodiment of the present invention may contain other additives in any ratio as necessary within a range that does not impair the effects of the present invention. However, it is desirable to add as few components as possible other than the essential components of the surface treatment composition according to one embodiment of the present invention, since they may cause foreign matter. Therefore, it is preferable that the amount of components other than the essential components is as small as possible, and it is more preferable that they are not included. Examples of other additives include abrasive grains, alkali, preservatives, dissolved gases, reducing agents, oxidizing agents, and alkanolamines. Among them, in order to further improve the foreign matter removal effect, it is preferable that the surface treatment composition does not substantially contain abrasive grains. Here, "substantially does not contain abrasive grains" refers to a case where the content of abrasive grains relative to the entire surface treatment composition is 0.01 mass% or less. The number of foreign matters (organic residues) is determined by carrying out a surface treatment according to the method described in the Examples and then measuring the number of foreign matters according to the method described in the Examples.

[0049] [Method of manufacturing the surface treatment composition] The method for producing the surface treatment composition is not particularly limited. For example, the surface treatment composition can be produced by mixing a polymer having a structural unit represented by the above formula (1), water, and at least one of an anionic surfactant and a nonionic surfactant. That is, according to another aspect of the present invention, a method for producing the surface treatment composition is also provided, which includes mixing a polymer having a structural unit represented by the above formula (1), water, and at least one of an anionic surfactant and a nonionic surfactant.

[0050] The type of polymer having a structural unit represented by the above formula (1), the type of anionic surfactant, the type of nonionic surfactant, and the amount of addition are as described above. Furthermore, in the method for producing a surface treatment composition according to one embodiment of the present invention, if necessary, a water-soluble polymer having a structural unit derived from glycerin (a glycerin-based water-soluble polymer), a pH adjuster, a chelating agent, other additives, a dispersion medium other than water, and the like may be further mixed. The types, amounts, and the like of these are as described above.

[0051] The order and method of adding the above components are not particularly limited. The above materials may be added all at once or separately, or stepwise or continuously. The mixing method is also not particularly limited, and a known method can be used. Preferably, the method for producing the surface treatment composition includes sequentially adding a water-soluble polymer having a structural unit derived from glycerin, water, at least one of an anionic surfactant and a nonionic surfactant, and a pH adjuster or the like added as necessary, and stirring in water. In addition, the method for producing the surface treatment composition may further include measuring and adjusting the pH of the surface treatment composition so that the pH is 7 or more and 12 or less.

[0052] [Surface treatment method] Another aspect of the present invention is a surface treatment method comprising treating a polished object with the above-mentioned surface treatment composition. In this specification, the surface treatment method refers to a method for reducing foreign matter on the surface of a polished object, and is a method for cleaning in a broad sense. According to the surface treatment method of one aspect of the present invention, foreign matter remaining on the surface of a polished object can be sufficiently removed. That is, according to another aspect of the present invention, there is provided a method for reducing foreign matter on a surface of a polished object, which comprises surface-treating the polished object with the above-mentioned surface treatment composition.

[0053] A surface treatment method according to one embodiment of the present invention is carried out by directly contacting the surface treatment composition according to the present invention with a polished object. The surface treatment methods mainly include (I) a method using a rinse polishing process and (II) a method using a cleaning process. That is, the surface treatment according to one embodiment of the present invention is preferably performed by rinse polishing or cleaning. The rinse polishing process and cleaning process are performed to remove foreign matter (particles, metal contamination, organic residues, pad debris, etc.) on the surface of the polished object to obtain a clean surface. The above (I) and (II) will be described below.

[0054] (I) Rinse polishing treatment The surface treatment composition according to the present invention is preferably used in a rinse polishing process. The rinse polishing process is carried out on a polishing table (platen) to which a polishing pad is attached, for the purpose of removing foreign matter on the surface of the polishing object after the final polishing (finish polishing) of the polishing object. At this time, the rinse polishing process is carried out by directly contacting the surface treatment composition according to the present invention with the polished object. As a result, the foreign matter on the surface of the polished object is removed by the frictional force (physical action) of the polishing pad and the chemical action of the surface treatment composition. Among the foreign matter, particles and organic residues are particularly easy to remove by physical action. Therefore, in the rinse polishing process, the friction with the polishing pad on the polishing table (platen) can be used to effectively remove particles and organic residues.

[0055] Specifically, the rinse polishing process can be carried out by placing the polished surface of the object to be polished after the polishing process on the polishing table (platen) of a polishing device, contacting the polishing pad with the polished semiconductor substrate, and sliding the polished object to be polished and the polishing pad relative to each other while supplying a surface treatment composition (rinse polishing composition) to the contact area. The rinse polishing process can be carried out by using either a single-sided polishing machine or a double-sided polishing machine. In addition, the polishing machine is preferably equipped with a nozzle for discharging the polishing composition and a nozzle for discharging the rinse polishing composition. The operating conditions of the polishing machine during the rinse polishing process are not particularly limited, and can be appropriately set by a person skilled in the art.

[0056] (II) Cleaning treatment The surface treatment composition according to the present invention is preferably used in a cleaning process. The cleaning process is carried out for the purpose of removing foreign matter on the surface of the object to be polished after the final polishing (finish polishing) of the object to be polished or after the above-mentioned rinse polishing process. The cleaning process and the above-mentioned rinse polishing process are classified according to the location where these processes are carried out, and the cleaning process is a surface treatment carried out after the polished object to be polished is removed from the polishing table (platen). In the cleaning process, the surface treatment composition according to the present invention can be directly brought into contact with the polished object to be polished to remove foreign matter on the surface of the object.

[0057] Examples of the method for performing the cleaning treatment include (i) a method in which a cleaning brush is brought into contact with one or both sides of a ground object to be polished while holding the ground object, and the surface of the object to be polished is rubbed with the cleaning brush while supplying a surface treatment composition to the contact portion, and (ii) a method in which the ground object to be polished is immersed in a surface treatment composition and subjected to ultrasonic treatment or stirring (dip type), etc. In such a method, foreign matter on the surface of the object to be polished is removed by the frictional force of the cleaning brush or the mechanical force generated by ultrasonic treatment or stirring, and the chemical action of the surface treatment composition.

[0058] In the above method (i), the method of contacting the surface treatment composition (cleaning composition) with the polished object to be polished is not particularly limited, but examples include a spin type in which the polished object to be polished is rotated at high speed while the surface treatment composition is flowed from a nozzle onto the polished object to be polished, and a spray type in which the surface treatment composition is sprayed onto the polished object to be polished and cleaned. From the viewpoint of more efficient decontamination in a short time, it is preferable to adopt a spin or spray type cleaning process, and the spin type is more preferable.

[0059] Apparatuses for carrying out such cleaning treatment include batch-type cleaning apparatuses that simultaneously perform surface treatment on multiple polished objects housed in a cassette, and single-wafer cleaning apparatuses that perform surface treatment on a single polished object mounted on a holder, etc. From the viewpoint of shortening the cleaning time, etc., a method using a single-wafer cleaning apparatus is preferred. Furthermore, as an apparatus for carrying out the cleaning process, there is a polishing apparatus equipped with a cleaning device for scrubbing the polished object with a cleaning brush after removing the polished object from the polishing table (platen). By using such a polishing apparatus, the cleaning process of the polished object can be carried out more efficiently.

[0060] As such a polishing device, a general polishing device having a holder for holding a polished object, a motor with a variable rotation speed, a cleaning brush, etc. can be used. As the polishing device, either a single-sided polishing device or a double-sided polishing device can be used. When a rinse polishing process is performed after the CMP process, it is more efficient and preferable to perform the cleaning process using the same device as the polishing device used in the rinse polishing process. The cleaning brush is not particularly limited, but preferably a resin brush is used. The material of the resin brush is not particularly limited, but for example, PVA (polyvinyl alcohol) is preferably used. And, it is particularly preferable to use a PVA sponge as the cleaning brush.

[0061] There is no particular restriction on the cleaning conditions, and they can be appropriately set according to the type of object to be cleaned and the type and amount of organic residue to be removed. For example, the rotation speed of the cleaning brush is preferably 10 rpm or more and 200 rpm or less, the rotation speed of the object to be cleaned is preferably 10 rpm or more and 100 rpm or less, and the pressure (polishing pressure) applied to the object to be cleaned is preferably 0.5 psi or more and 10 psi or less. There is no particular restriction on the method of supplying the surface treatment composition to the cleaning brush, and for example, a method of continuously supplying the composition using a pump or the like (flowing over) is adopted. There is no restriction on the amount of supply, but it is preferable that the surfaces of the cleaning brush and the object to be cleaned are always covered with the surface treatment composition, and it is preferably 10 mL / min or more and 5000 mL / min or less. There is no particular restriction on the cleaning time, but it is preferably 5 seconds or more and 180 seconds or less for the process using the surface treatment composition according to one embodiment of the present invention. If it is within such a range, it is possible to remove foreign matter more effectively.

[0062] The temperature of the surface treatment composition during cleaning is not particularly limited and may usually be room temperature (25° C.), but may be heated to about 40° C. or higher and 70° C. or lower within a range that does not impair performance. In the above method (ii), the conditions for the cleaning method by immersion are not particularly limited, and any known method can be used. Washing with water may be carried out before or after the washing treatment by the above method (i) or (ii), or both. In addition, the polished object (cleaned object) after cleaning is preferably dried by removing water droplets adhering to the surface using a spin dryer or the like. The surface of the cleaned object may also be dried by air blow drying.

[0063] [Method of manufacturing semiconductor substrate] The surface treatment method according to one aspect of the present invention is preferably applicable when the polished object is a polished semiconductor substrate. That is, according to another aspect of the present invention, there is also provided a method for producing a semiconductor substrate, the method comprising: surface treating the polished semiconductor substrate with the above-mentioned surface treatment composition, the polished object being a polished semiconductor substrate. Details of the semiconductor substrate to which this manufacturing method is applied are as described above for the polished object to be surface-treated with the surface treatment composition. In addition, the method for producing a semiconductor substrate is not particularly limited as long as it includes a step (surface treatment step) of surface-treating the surface of a polished semiconductor substrate using a surface treatment composition according to one embodiment of the present invention. For example, such a production method includes a method having a polishing step and a cleaning step for forming a polished semiconductor substrate. Another example includes a method having a rinse polishing step between the polishing step and the cleaning step in addition to the polishing step and the cleaning step. Each of these steps will be described below.

[0064] <Polishing process> A polishing step that can be included in the method for manufacturing a semiconductor substrate is a step of polishing a semiconductor substrate to form a polished semiconductor substrate. The polishing step is not particularly limited as long as it is a step for polishing a semiconductor substrate, but is preferably a chemical mechanical polishing (CMP) step. The polishing step may be a polishing step consisting of a single step or a polishing step consisting of multiple steps. Examples of the polishing step consisting of multiple steps include a pre-polishing step. Examples of such a process include a process of performing a finish polishing process after a preliminary polishing process (rough polishing process), a process of performing a secondary polishing process once or twice or more times after a primary polishing process, and then performing a finish polishing process, etc. The surface treatment process using the surface treatment composition according to the present invention is preferably performed after the above-mentioned finish polishing process.

[0065] As the polishing composition, a known polishing composition can be appropriately used according to the characteristics of semiconductor substrate.As the polishing composition, there is no particular limitation, but for example, the one containing abrasive grains, acid salt, dispersion medium, and acid can be preferably used.Specific examples of such polishing compositions include the polishing composition containing ceria, polyacrylic acid, water, and maleic acid. As the polishing device, a general polishing device can be used, which is equipped with a holder for holding the object to be polished, a motor capable of changing the rotation speed, etc., and a polishing platen to which a polishing pad (polishing cloth) can be attached. As the polishing device, either a single-sided polishing device or a double-sided polishing device can be used.

[0066] The polishing pad may be made of any material, including, without particular limitation, a general nonwoven fabric, polyurethane, porous fluororesin, etc. The polishing pad is preferably provided with grooves for storing the polishing liquid. There is no particular restriction on the polishing conditions, and for example, the rotation speed of the polishing platen and the rotation speed of the head (carrier) are preferably 10 rpm or more and 100 rpm or less, and the pressure (polishing pressure) applied to the object to be polished is preferably 0.5 psi or more and 10 psi or less. There is no particular restriction on the method of supplying the polishing composition to the polishing pad, and for example, a method of continuously supplying the composition using a pump or the like (flowing the composition). There is no particular restriction on the amount of supply, but it is preferable that the surface of the polishing pad is always covered with the polishing composition, and it is preferably 10 mL / min or more and 5000 mL / min or less. There is no particular restriction on the polishing time, but it is preferable that the step of using the polishing composition is 5 seconds or more and 180 seconds or less.

[0067] <Surface treatment process> The surface treatment step refers to a step of reducing foreign matter on the surface of a polished object using the surface treatment composition according to the present invention. In the method for producing a semiconductor substrate, a cleaning step may be performed as a surface treatment step after the rinse-polishing step, or only the rinse-polishing step or only the cleaning step may be performed.

[0068] (Rinse polishing process) The rinse-polishing step may be provided between the polishing step and the cleaning step in the method for manufacturing a semiconductor substrate. The rinse-polishing step is a step for reducing foreign matter on the surface of a polished object (polished semiconductor substrate) by a surface treatment method (rinse-polishing method) according to one embodiment of the present invention. Regarding the equipment such as the polishing apparatus and polishing pad, as well as the polishing conditions, the same equipment and conditions as those in the above-mentioned polishing process can be applied, except that the surface treatment composition of the present invention is supplied instead of the polishing composition. The details of the rinse polishing method used in the rinse polishing step are as described above in the explanation of the rinse polishing treatment.

[0069] (Cleaning process) In the method for manufacturing a semiconductor substrate, the cleaning step may be performed after the polishing step or after the rinse-polishing step. The cleaning step is a step for reducing foreign matter on the surface of a polished object (polished semiconductor substrate) by a surface treatment method (cleaning method) according to one embodiment of the present invention. Details of the cleaning method used in the cleaning step are as described above in the description of the cleaning method. EXAMPLES

[0070] 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 "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were performed under the conditions of room temperature (25°C) / relative humidity 40-50%RH. The weight-average molecular weight of each polymer compound was measured using a weight-average molecular weight (converted into polyethylene glycol) value measured by gel permeation chromatography (GPC), more specifically, using the following apparatus and conditions.

[0071] GPC equipment: Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII) Column: VP-ODS (Shimadzu Corporation) Mobile phase A:MeOH B: 1% acetic acid solution Flow rate: 1mL / min Detector: ELSD temp. 40℃, Gain 8, N2GAS 350kPa Oven temperature: 40℃ Injection volume: 40μL

[0072] <Preparation of Surface Treatment Composition> [Example 1: Preparation of surface treatment composition (A-1)] 1.25 g / L of poly-N-vinylacetamide (weight average molecular weight (Mw): 50,000; the constituent unit represented by formula (1) is 100 mol%) and 1.00 g / L of ammonium dodecyl sulfate (weight average molecular weight (Mw): 288) as an anionic surfactant were mixed with water (deionized water), and ammonium acetate as a pH adjuster was added in an amount to adjust the pH to 8.7 to prepare a surface treatment composition (A-1). The pH of the surface treatment composition (A-1) (liquid temperature: 25°C) was measured with a pH meter (manufactured by Horiba Ltd., product name: LAQUA (registered trademark)). In Table 1, PNVA stands for "poly-N-vinylacetamide".

[0073] [Examples 2 to 10 and Comparative Examples 1 to 6: Preparation of surface treatment compositions (A-2) to (A-10) and (a-1) to (a-6)] Each surface treatment composition was prepared in the same manner as in Example 1, except that each component was used with the type, molecular weight, and content shown in Table 1, and the pH of each surface treatment composition was adjusted to the pH shown in Table 1. In Table 1, "-" indicates that the corresponding component was not used. In Table 1, PSS-PA stands for "polystyrene sulfonic acid-acrylic acid copolymer."

[0074] It should be noted that PSS-PA is an anionic polymer and not a surfactant. In other words, PSS-PA does not function as a surfactant because the alkyl chain in the hydrophobic part is longer and the molecular weight of the hydrophobic part is larger than that of anionic surfactants. In Table 1, ammonium dodecyl sulfate is classified as an anionic surfactant. Polyglycerol lauryl ether is classified as a nonionic surfactant. Polyglycerol lauryl ether has a larger overall molecular weight than ammonium dodecyl sulfate, but the hydrophobic portion of polyglycerol lauryl ether has a low molecular weight similar to that of ammonium dodecyl sulfate. For this reason, polyglycerol lauryl ether functions as a surfactant.

[0075] <Evaluation> <Preparation of polished object (object for surface treatment)> Polished silicon nitride substrates and polished polysilicon substrates after being polished by the chemical mechanical polishing (CMP) process described below, or polished silicon nitride substrates and polished polysilicon substrates after being further treated by the rinsing process described below as required, were prepared as surface treatment objects.

[0076] [CMP process] The silicon nitride substrate and the polysilicon substrate, which are semiconductor substrates, were polished under the following conditions using the polishing composition M (composition: ceria, primary particle size 60 nm, secondary particle size 100 nm) 1% by mass, 0.18% by mass of maleic acid aqueous solution with a concentration of 30% by mass, 0.25% by mass of polyacrylic acid (molecular weight: 6,000), solvent: water). Here, 300 mm wafers were used for the silicon nitride substrate and the polysilicon substrate.

[0077] (Polishing equipment and polishing conditions) Polishing equipment: Ebara Corporation FREX 300E Polishing pad: Fujibo Co., Ltd. Soft pad H800 Polishing pressure: 2.0 psi (1 psi = 6894.76 Pa, same below) Polishing platen rotation speed: 90 rpm Head rotation speed: 90 rpm Supply of polishing composition: free-flowing Polishing composition supply amount: 200mL / min Polishing time: 60 seconds

[0078] [Rinse polishing process] The polished silicon nitride substrate and the polished polysilicon substrate after being polished by the above CMP process were removed from the polishing table (platen). Then, in the same polishing apparatus, the polished substrates were mounted on another polishing table (platen), and the surfaces of the substrates were subjected to a rinse polishing treatment using the above-prepared surface treatment compositions under the following conditions.

[0079] (Polishing equipment and polishing conditions) Polishing equipment: Ebara Corporation FREX 300E Polishing pad: Fujibo Co., Ltd. Soft pad H800 Polishing pressure: 1.0 psi (1 psi = 6894.76 Pa, same below) Polishing platen rotation speed: 60 rpm Head rotation speed: 60 rpm Supply of polishing composition: free-flowing Polishing composition supply amount: 300mL / min Polishing time: 60 seconds (Water washing process) After the rinse-polishing, each of the substrates obtained above was washed for 60 seconds in a washing section while spraying deionized water (DIW) using a PVA brush, and then dried for 30 seconds in a spin dryer.

[0080] <Evaluation> The following items were measured and evaluated for each of the substrates obtained after the water washing step. The evaluation results are shown in Table 2. [Measurement of number of defects] The number of defects was measured for the silicon nitride substrate (over 38 nm) and polysilicon substrate (over 55 nm) after the surface treatment obtained after the water washing process. A KLA TENCOR wafer defect inspection device SP-5 was used to measure the number of defects. The measurement was performed on the remaining part excluding the part 3 mm wide from the outer edge of each substrate surface after surface treatment (the part from 0 mm wide to 3 mm wide when the outer edge is set to 0 mm). Table 1 shows the evaluation results for each surface treatment composition when a polished silicon nitride substrate and a polished polysilicon substrate were used as the surface treatment object.

[0081] [Table 1]

[0082] As is clear from Table 1 above, it was found that the alkaline surface treatment composition of the Example can reduce the number of defects on the polished surface of an object to be polished, compared to the alkaline surface treatment composition of the Comparative Example. Specifically, it was found that the surface treatment compositions of Examples 1 to 9, which contain poly-N-vinylacetamide and ammonium dodecyl sulfate and have a pH of 7.5 to 12, can particularly reduce the number of defects on the polished silicon nitride substrate surface, compared with Comparative Examples 5 and 6, which contain poly-N-vinylacetamide, do not contain ammonium dodecyl sulfate, and have a pH of 9.3. It was also found that the surface treatment composition of Example 10, which contains poly-N-vinylacetamide and polyglycerin lauryl ether and has a pH of 9.3, can reduce the number of defects on the polished silicon nitride substrate surface, compared with Comparative Examples 5 and 6, which contain poly-N-vinylacetamide, do not contain polyglycerin lauryl ether, and have a pH of 9.3.

[0083] From these results, it was found that in alkaline surface treatment compositions, ammonium dodecyl sulfate or polyglycerin lauryl ether is highly effective in reducing the number of defects on the polished silicon nitride substrate surface. The mechanism of the reduction in the number of defects is considered to be that ammonium dodecyl sulfate or polyglycerin lauryl ether disperses and removes particles and organic residues attached to the polished silicon nitride substrate surface.

[0084] In addition, it was found that the surface treatment compositions of the above Examples 1 to 10 can reduce the number of defects on the polished silicon nitride substrate surface and the polished polysilicon substrate surface, compared to Comparative Examples 3 and 4, which do not contain poly-N-vinylacetamide, contain ammonium dodecyl sulfate or polyglycerin lauryl ether, and have a pH of 9.3. In particular, Examples 1 to 10 have a greater effect of reducing the number of defects on the polished polysilicon substrate surface, compared to Comparative Examples 3 and 4. From this result, it was found that in an alkaline surface treatment composition, poly-N-vinylacetamide has an effect of reducing the number of defects on the polished silicon nitride substrate surface and the polished polysilicon substrate surface, and is particularly effective in reducing the number of defects on the polished polysilicon substrate surface. As a mechanism for reducing the number of defects, it is considered that poly-N-vinylacetamide hydrophilizes the polished polysilicon substrate surface and removes organic residues.

[0085] From the above, it was found that by using poly-N-vinylacetamide in combination with ammonium dodecyl sulfate or polyglycerin lauryl ether in an alkaline surface treatment composition, defects (e.g., organic residues) on the polished silicon nitride substrate surface and the polished polysilicon substrate surface can be sufficiently removed.

Claims

1. A polymer having a structural unit represented by formula (1) shown below in [Chemical Formula 1]: At least one of ammonium dodecyl sulfate and polyglycerol lauryl ether, and Contains water, 1. A surface treatment composition for use in treating a surface of a polished semiconductor substrate comprising silicon nitride or polysilicon, comprising: 【Chemistry 1】 A surface treatment composition, wherein in the above formula (1), R1 is a hydrocarbon group having 1 to 5 carbon atoms, and R2 is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

2. The surface treatment composition according to claim 1 , which has a pH of 7 or more and 12 or less.

3. 3. The surface treatment composition according to claim 1, which is substantially free of abrasive grains.

4. The surface treatment composition according to claim 1 , wherein the weight average molecular weight of the polymer is 50,000 or more and 900,000 or less.

5. A method for producing a surface treatment composition used for treating a surface of a polished semiconductor substrate containing silicon nitride or polysilicon, comprising the step of mixing a polymer having a constitutional unit represented by formula (1) of the following [Chemical Formula 2], at least one of ammonium dodecyl sulfate and polyglycerin lauryl ether, and water, 【Chemistry 2】 A method for producing a surface treatment composition, wherein in the above formula (1), R1 is a hydrocarbon group having 1 to 5 carbon atoms, and R2 is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

6. A surface treatment method comprising: treating a polished semiconductor substrate containing silicon nitride or polysilicon with the surface treatment composition according to any one of claims 1 to 4, thereby reducing organic residues on the surface of the polished semiconductor substrate.

7. The surface treatment method according to claim 6 , wherein the surface treatment includes rinsing or cleaning.

8. 8. A method for manufacturing a semiconductor substrate, comprising a surface treatment step of reducing organic residues on the surface of a polished semiconductor substrate containing silicon nitride or polysilicon by the surface treatment method according to claim 6 or 7.

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