KR102122049B1 - Texture etching solution composition and texture etching method of crystalline silicon wafers - Google Patents

Abstract

The present invention relates to a texture etching solution composition and a texture etching method of a crystalline silicon wafer, and more specifically, includes an alkali compound and a water-soluble glucan-based compound having a polymerization degree of 1,000 or less, and the water-soluble glucan-based compound is alkyl having 1 to 3 carbon atoms. Silicon crystals in forming a fine pyramidal structure on the surface of a crystalline silicon wafer by polymerizing with glucose substituted with a carboxyl group or a metal salt thereof, and the total substitution degree of the carboxyl group or a metal salt thereof is 0.5 to 1.2. The present invention relates to a texture etchant composition and a texture etching method of a crystalline silicon wafer that increases light efficiency by minimizing quality variations of textures by location by controlling a difference in etching speed for a direction to prevent overetching by an alkali compound.

Description

Texture etching solution composition and texture etching method of crystalline silicon wafer {TEXTURE ETCHING SOLUTION COMPOSITION AND TEXTURE ETCHING METHOD OF CRYSTALLINE SILICON WAFERS}

The present invention relates to a texture etchant composition and a texture etching method of a crystalline silicon wafer that minimizes texture quality variations for each location on the surface of the crystalline silicon wafer and does not generate a temperature gradient during etching.

2. Description of the Related Art Solar cells, which are rapidly spreading in recent years, are electronic devices that directly convert solar energy, which is clean energy, into electricity as a next-generation energy source. The solar cell is composed of a PN junction semiconductor substrate in which phosphorus is diffused on its surface to form an N-type silicon semiconductor layer based on a P-type silicon semiconductor in which boron is added to silicon.

When light such as sunlight is irradiated on a substrate where an electric field is formed by PN bonding, electrons (-) and holes (+) in the semiconductor are excited to move freely inside the semiconductor, and the electric field generated by the PN bonding When it comes in, electrons (-) reach the N-type semiconductor, and holes (+) reach the P-type semiconductor. When electrodes are formed on the surfaces of the P-type semiconductor and the N-type semiconductor to flow electrons to the external circuit, a current is generated. In this way, solar energy is converted into electrical energy. Therefore, in order to increase the conversion efficiency of solar energy, the electrical output per unit area of the PN junction semiconductor substrate must be maximized, and for this, the reflectance must be low and the amount of light absorption must be maximized. In consideration of these points, the surface of the silicon wafer for solar cells constituting the PN junction semiconductor substrate is formed in a fine pyramid structure and treated with an antireflection film. The surface of the silicon wafer textured with the fine pyramid structure can increase the performance of the solar cell, that is, efficiency, by increasing the intensity of light absorbed by lowering the reflectance of incident light having a wide wavelength band.

As a method of texturing a silicon wafer surface with a fine pyramid structure, U.S. Patent No. 4,137,123 discloses 0.5-10% by weight of an anisotropic etching solution containing 0-75% by volume of ethylene glycol, 0.05-50% by weight of potassium hydroxide, and residual water. A silicon texture etching solution in which% silicon is dissolved is disclosed. However, this etchant can cause pyramid formation defects, thereby increasing light reflectivity and lowering efficiency.

In addition, Korean Patent Registration No. 0180621 discloses a texture etching solution mixed in a ratio of 0.5-5% of potassium hydroxide solution, 3-20% by volume of isopropyl alcohol, and 75-96.5% by volume of deionized water, and US Patent No. 6,451,218 The heading discloses a texture etching solution comprising an alkali compound, isopropyl alcohol, water-soluble alkaline ethylene glycol and water. However, since these etching solutions contain isopropyl alcohol having a low boiling point, it is not economical in terms of productivity and cost because it must be added during the texture process, and the temperature of the etching solution is generated due to the added isopropyl alcohol, resulting in a silicon wafer surface. The variation in texture quality for each position of can be increased, resulting in poor uniformity.

Patent Document 1: U.S. Patent Publication 4,137,123 Patent Literature 2: Korean Registered Patent Publication 10-0180621

In the present invention, in forming a fine pyramid structure on the surface of a crystalline silicon wafer, by controlling the difference in the etching rate with respect to the silicon crystal direction to prevent over-etching by an alkali compound, light quality is minimized by minimizing the quality variation of textures by location. It is an object to provide a texture etchant composition of a crystalline silicon wafer to increase the.

In addition, an object of the present invention is to provide a texture etchant composition of a crystalline silicon wafer in which a separate etchant component is not required during the etching process and a temperature gradient does not occur during etching.

In addition, another object of the present invention is to provide a texture etching method using the texture etchant composition of the crystalline silicon wafer.

1.Contains an alkali compound and a water-soluble glucan-based compound having a polymerization degree of 1,000 or less,

The water-soluble glucan-based compound is polymerized with glucose substituted with an alkyl carboxyl group having 1 to 3 carbon atoms or a metal salt thereof, and the total degree of substitution of the carboxyl group or a metal salt thereof is 0.5 to 1.2, and a texture etching solution composition for a crystalline silicon wafer.

2. In the above 1, wherein the glucan-based compound is at least one selected from the group consisting of carboxymethylcellulose, carboxyethylcellulose, carboxypropylcellulose, carboxybutylcellulose, and metal salts thereof, the texture etching solution composition of the crystalline silicon wafer.

3. In the above 2, wherein the unit of the substituted cellulose is cellobiose, the texture etchant composition of the crystalline silicon wafer.

4. In the above 1, wherein the glucan-based compound is contained in 10 ^-9 to 0.5% by weight relative to the total 100% by weight of the etching solution composition, the texture etching solution composition of a crystalline silicon wafer.

5. In the above 1, wherein the alkali compound is at least one selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium and tetrahydroxyethylammonium, texture etching solution composition of a crystalline silicon wafer.

6. In the above 1, the etchant composition of the crystalline silicon wafer further comprises a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms containing at least one nitrogen atom is polymerized.

7. In the above 6, wherein the monomer further comprises at least one of oxygen and sulfur atoms in the ring structure, the texture etchant composition of the crystalline silicon wafer.

8. In the above 6, wherein the monomer is N-vinylpyrrolidone, N-acryloyl morpholine, N-vinyl succinimide, N-acryloxy succinimide, N-vinyl caprolactam, N-vinyl cover A texture etchant composition of a crystalline silicon wafer, which is at least one selected from the group consisting of sol and N-acryloylpyrrolidine.

9. In the above 6, wherein the polymer has a weight-average molecular weight of 1,000 to 1,000,000, the texture etching solution composition of a crystalline silicon wafer.

10. The method of 6 above, wherein the polymer has a boiling point of 100°C or higher, and a texture etching solution composition of a crystalline silicon wafer.

11. In the above 6, wherein the polymer has a solubility parameter of Hansen is 6 to 15, the texture etchant composition of the crystalline silicon wafer.

12. In the above 6, wherein the polymer is 10 ^-12 to 1% by weight based on the total weight of the etchant composition, the texture etchant composition of the crystalline silicon wafer.

13. The texture etching solution composition of the crystalline silicon wafer according to the above 1, further comprising a cyclic compound.

14. In the above 13, the cyclic compound has a boiling point of 100 °C or more, the texture etching solution composition of a crystalline silicon wafer.

15. The texture etchant composition of the crystalline silicon wafer according to the above 13, wherein the cyclic compound has a Hansen solubility parameter of 6 to 15.

16. A method for texture etching a crystalline silicon wafer using the etchant composition of any one of 1 to 15 above.

17. The method of 16 above, comprising spraying the etchant composition at a temperature of 50 to 100° C. for 30 seconds to 60 minutes.

18. The method of 16 above, wherein the wafer is immersed in the etchant composition at a temperature of 50 to 100°C for 30 seconds to 60 minutes.

According to the texture etchant composition and the texture etching method of the crystalline silicon wafer of the present invention, by controlling the difference in the etch rate with respect to the silicon crystal direction, it prevents over-etching by the alkali compound, and thus the quality deviation of the texture by position of the surface of the crystalline silicon wafer Minimizes, that is, improves the uniformity of the texture to maximize the absorption of sunlight.

In addition, since the texture etchant composition of the crystalline silicon wafer of the present invention does not need to input a separate etchant component during the texture process, a temperature gradient does not occur during etching, thereby obtaining a texture structure of uniform quality.

1 is a graph of molecular weight calculation of glucan compounds used in Examples and Comparative Examples.
2 is an optical microscope photograph showing the texture of a single crystal silicon wafer etched using the etching solution composition for texture of the crystalline silicon wafer of Example 3.
3 is an optical micrograph showing the surface of a single crystal silicon wafer textured with an etching solution composition for texture of the crystalline silicon wafer of Example 7.
FIG. 4 is an optical micrograph showing the surface of a single crystal silicon wafer textured with an etching solution composition for texture of the crystalline silicon wafer of Comparative Example 1.

The present invention includes a water-soluble glucan-based compound having an alkali compound and a polymerization degree of 1,000 or less, polymerized with glucose substituted with an alkyl carboxyl group having 1 to 3 carbon atoms or a metal salt thereof, and having a total substitution degree of the alkylcarboxyl group or a metal salt thereof being 0.5 to 1.2. By controlling the difference in the etching rate with respect to the silicon crystal direction in forming a fine pyramid structure on the surface of the water-soluble crystalline silicon wafer, it prevents over-etching by the alkali compound, thereby minimizing the quality deviation of the texture for each location, thereby improving light efficiency. The present invention relates to a texture etchant composition and a texture etching method for increasing crystalline silicon wafers.

Hereinafter, the present invention will be described in detail.

The texture etchant composition of the crystalline silicon wafer of the present invention includes an alkali compound and a water-soluble glucan-based compound, wherein the water-soluble glucan-based compound has a polymerization degree of 1,000 or less, and an alkyl carboxyl group having 1 to 3 carbon atoms or glucose substituted with a metal salt thereof Polymerized, the total substitution degree of the alkyl carboxyl group or its metal salt is 0.5 to 1.2.

The water-soluble glucan-based compound according to the present invention controls the difference in the etching rate with respect to the silicon crystal direction to prevent over-etching by the alkali compound, thereby minimizing the quality variation of the texture, and the hydrogen bubble, which is the product during the reaction between the alkali compound and silicon, By quickly dropping from the silicon surface, it is possible to improve the appearance of the silicon wafer and prevent accelerated etching by hydrogen.

When the degree of polymerization of the water-soluble glucan-based compound exceeds 1,000, there is a problem in that an overetching phenomenon of silicon occurs.

In addition, the water-soluble glucan-based compound is polymerized with glucose substituted with an alkyl carboxyl group having 1 to 3 carbon atoms or a metal salt thereof, and the total substitution degree of the alkyl carboxyl group or a metal salt thereof may be 0.5 to 1.2, preferably 0.7 to 1.0. It is good.

When the degree of substitution is less than 0.5, the control effect of the etching rate is excessive, and etching may not occur properly, and when it exceeds 1.2, it causes overetching of the silicon wafer, and it is difficult to form a desired fine pyramid.

In the present invention,'substitution degree' means the number of substituted alkyl carboxyl groups or one metal salt substituent per molecule of glucose.

In addition, glucose, which is a unit of the water-soluble glucan-based compound, may be further substituted with a cyano group, an amino group, a benzyl group, or an alkyl group having 1 to 3 carbon atoms, and the alkyl group may be a hydroxy group, a cyano group, an amino group, or an alkyl group (1 to 3 carbon atoms). ) An amino group, a dialkyl (1 to 3 carbon atoms) amino group, a benzyl group or an aminobenzyl group may be further substituted.

Examples of the glucan-based compound according to the present invention include carboxymethyl cellulose, carboxyethyl cellulose, carboxypropyl cellulose, carboxybutyl cellulose, and metal salts thereof.

The metal salt may be a salt of a monovalent cation metal, for example, an alkali metal.

In the aforementioned substituted cellulose, the cellulosic unit is cellobiose. The structure of cellobiose is represented by the following formula (1).

For a more specific example, the repeating unit of the sodium salt of carboxymethylcellulose may be represented by Formula 2 below.

The glucan-based compound according to the present invention may be included in 10 ^-9 to 0.5% by weight based on the total weight of the texture etchant composition of the crystalline silicon wafer, preferably 10 ^-6 to 0.1% by weight. When the content falls within the above range, it is possible to effectively prevent over-etching and etching acceleration. When the content is more than 0.5% by weight, it is difficult to form a desired fine pyramid by rapidly decreasing the etching rate by the alkali compound.

The alkali compound according to the present invention can be used without limitation as long as it is an alkali compound commonly used in the art as a component for etching the surface of the crystalline silicon wafer. Examples of the alkali compound that can be used include potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium, and tetrahydroxyethylammonium, among which potassium hydroxide and sodium hydroxide are preferred. These may be used alone or in combination of two or more.

The alkali compound is preferably included in an amount of 0.1 to 20% by weight based on the total weight of the texture etchant composition of the crystalline silicon wafer, and more preferably 1 to 5% by weight. When the content falls within the above range, the silicon wafer surface can be etched.

Optionally, the texture etchant composition of the crystalline silicon wafer of the present invention may further include a polymer in which monomers substituted with ring compounds having 4 to 10 carbon atoms containing at least one nitrogen atom are polymerized.

The polymer can minimize the variation in the quality of the texture by preventing over-etching by the alkali compound by controlling the difference in the etching rate with respect to the silicon crystal direction, and the bubble stick phenomenon by rapidly reducing the amount of hydrogen bubbles generated by etching This can also be suppressed.

The polymer is formed by polymerization of a monomer substituted with a cyclic compound having 4 to 10 carbon atoms containing at least one nitrogen atom, and the monomer has, in addition to nitrogen, oxygen or sulfur atoms alone or all of them, at least one or more of them, in their ring structure. It may further include. Specific examples of such monomers include N-vinylpyrrolidone, N-acryloyl morpholine, N-vinyl succinimide, N-acryloxysuccinimide, N-vinyl caprolactam, N-vinyl carbazole, It may be one or more selected from the group consisting of N-acryloylpyrrolidine and the like.

The polymer according to the present invention has a weight average molecular weight of 1,000 to 1,000,000, which is preferable in that it can lower the reflectivity by increasing the base angle of the pyramid, as well as forming a uniform pyramid on the entire surface of the single crystal silicon wafer.

In addition, in the polymer according to the present invention, a boiling point of 100° C. or higher is preferable in terms of reducing the amount of use, and more preferably 150 to 400° C. At the same time, the polymer according to the present invention is preferably Hansen solubility parameter (HSP), δp of 6 to 15 in terms of compatibility with other components included in the etchant composition.

The polymer according to the present invention may have a content of 10 ^-12 to 1% by weight based on the total weight of the etchant composition. When the content falls within the above range, the effect of controlling the difference in the etching rate with respect to the crystal direction of silicon is maximized.

The polymer according to the present invention may be mixed with a water-soluble polar solvent.

The water-soluble polar solvent is not particularly limited as long as it is compatible with other components and water included in the texture etchant composition of the crystalline silicon wafer, and both quantum or aprotic polar solvents can be used.

As the quantum polar solvent, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether , Ether-based compounds such as diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether; And alcohol-based compounds such as propanol, butanol, isopropanol, tetrahydrofurfuryl alcohol, ethylene glycol, and propylene glycol. Examples of the aprotic polar solvent include amides such as N-methylformamide and N,N-dimethylformamide. Compound; Sulfoxide compounds such as dimethyl sulfoxide and sulfolane; And phosphate-based compounds such as triethyl phosphate and tributyl phosphate. These may be used alone or in combination of two or more.

Optionally, the texture etchant composition of the crystalline silicon wafer of the present invention may further include a cyclic compound.

The cyclic compound may be a cyclic hydrocarbon having 4 to 10 carbon atoms; And a heterocyclic hydrocarbon having 4 to 10 carbon atoms, including one or more heteroatoms of N, O, or S, and improving the wettability of the crystalline silicon wafer surface, thereby over-etching with an alkali compound. It is a component that can prevent the occurrence of bubble stick phenomenon by quickly reducing the amount of hydrogen bubbles generated by etching while minimizing texture quality variation by preventing it. In addition, since it has a high boiling point, it can be used in a smaller amount than the conventionally used isopropyl alcohol, and it can also increase the number of treatments for the same amount.

The cyclic compound preferably has a boiling point higher than 100°C, more preferably 150 to 400°C. At the same time, the cyclic compound has a Hansen solubility parameter (HSP), δp of 6 to 15, in terms of compatibility with other components included in the etchant composition.

The cyclic compound is not particularly limited as long as it satisfies the boiling point and solubility parameters of Hansen, for example, piperazine-based, morpholine-based, pyridine-based, piperidine-based, piperidone-based, pyrrolidine-based, pyrrolidone-based , Imidazolidinone series, furan series, aniline series, toluidine series, amine series, lactone series, carbonate series, and carbazole series compounds. Specific examples include piperazine, N-methylpiperazine, N-ethylpiperazine, N-vinylpiperazine, N-vinylmethylpiperazine, N-vinylethylpiperazine, N-vinyl-N'-methylpiperazine, N-acryloylpiperazine, N-acryloyl-N'-methylpiperazine, hydroxyethylpiperazine, N-(2-aminoethyl)piperazine, N,N'-dimethylpiperazine; Morpholine, N-methylmorpholine, N-ethylmorpholine, N-phenylmorpholine, N-vinylmorpholine, N-vinylmethylmorpholine, N-vinylethylmorpholine, N-acryloylmorpholine, N -Cocomorpholine, N-(2-aminoethyl)morpholine, N-(2-cyanoethyl)morpholine, N-(2-hydroxyethyl)morpholine, N-(2-hydroxypropyl)morph Folin, N-acetylmorpholine, N-formylmorpholine, N-methylmorpholine-N-oxide; Methylpyridine; N-methylpiperidine, 3,5-dimethylpiperidine, N-ethylpiperidine, N-(2-hydroxyethyl)piperidine; N-vinyl piperidone, N-vinyl methyl piperidone, N-vinyl ethyl piperidone, N-acryloyl piperidone, N-methyl-4-piperidone, N-vinyl-2-piperidone; N-methylpyrrolidine; N-vinylpyrrolidone, N-vinylmethylpyrrolidone, N-vinylethyl-2-pyrrolidone, N-acryloylpyrrolidone, N-methylpyrrolidone, N-ethyl-2-pyrrolidone , N-isopropyl-2-pyrrolidone, N-butyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, N-hexyl-2-pyrrolidone, N-octyl-2-pyrrolidone Don, N-benzyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-(2-hydroxyethyl)-2-pyrrolidone, N -(2-methoxyethyl)-2-pyrrolidone, N-(2-methoxypropyl)-2-pyrrolidone, N-(2-ethoxyethyl)-2-pyrrolidone; N-methyl imidazolidinone, dimethylimidazolidinone, N-(2-hydroxyethyl)-2-imidazolidinone; Tetrahydrofuran, tetrahydro-2-furanmethanol; N-methylaniline, N-ethylaniline, N,N-dimethylaniline, N-(2-hydroxyethyl)aniline, N,N-bis-(2-hydroxyethyl)aniline, N-ethyl-N-( 2-hydroxyethyl)aniline; N,N-diethyl-o-toluidine, N-ethyl-N-(2-hydroxyethyl)-m-toluidine; Dimethylbenzylamine; γ-butyrolactone; Ethylene carbonate, propylene carbonate; N-vinyl carbazole, N-acryloyl carbazole, and the like, and these may be used alone or in combination of two or more.

The cyclic compound is preferably included in an amount of 0.1 to 50% by weight, more preferably 1 to 10% by weight, based on 100% by weight of the total texture etchant composition of the crystalline silicon wafer. When the content falls within the above range, uniformity can be improved by effectively improving the wettability of the silicon wafer surface and minimizing texture quality variations.

The cyclic compound may be mixed with a water-soluble polar solvent.

The water-soluble polar solvent may use the same solvent as the polymer. The water-soluble polar solvent may be included in an amount of 0.1 to 30% by weight based on 100% by weight of the total cyclic compound.

Optionally, the texture etchant composition of the crystalline silicon wafer of the present invention comprises a fatty acid or a metal salt thereof; And one or more additives selected from the group consisting of polyoxyethylene-based (POE) compounds, polyoxypropylene-based (POP) compounds, and surfactants that are copolymers thereof.

Fatty acids and metal salts thereof are used together with polysaccharides to prevent over-etching by alkali compounds to form a uniform micro-pyramid, while simultaneously preventing hydrogen bubbles generated by etching from falling off the silicon wafer surface to prevent bubble sticking. It is an ingredient to do.

Fatty acids are carboxylic acids of hydrocarbon chains containing carboxy groups, specifically acetic acid, propionic acid, butyl acid, valeric acid, enanthic acid, caprylic acid, pelagonic acid, capric acid, lauric acid, myristic acid, palmitic acid, Stearic acid, arachidic acid, behenic acid, lignoseric acid, serotic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, And oleic acid, eleic acid, erucic acid and nerbonic acid. Further, the metal salt of the fatty acid may include an ester reactant of the above fatty acid with a metal salt such as NaOH or KOH. These may be used alone or in combination of two or more.

The fatty acid and metal salts thereof may be included in 10 ^-9 to 10% by weight based on the total weight of the texture etching solution composition of the crystalline silicon wafer, and preferably 10 ^-6 to 1% by weight. When the content falls within the above range, over-etching can be effectively prevented.

And Si ₁₀₀ direction by controlling the activity ^of-a polyoxyethylene-based (POE) compounds, polyoxypropylene-based (POP) compounds and copolymers thereof is a hydroxy ion [OH] of the texture etching solution composition as a surface active agent having a hydroxy group It is a component that not only reduces the difference in the etching rate with respect to the Si ₁₁₁ direction, but also improves the wettability of the surface of the crystalline silicon wafer, thereby rapidly dropping the hydrogen bubbles generated by etching, and preventing bubble sticking.

Polyoxyethylene-based (POE) surfactants include polyoxyethylene glycol, polyoxyethylene glycol methyl ether, polyoxyethylene monoallyl ether, polyoxyethylene neopentyl ether, polyethylene glycol mono (tristyrylphenyl) ether, and polyoxy Ethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene tridecyl ether, polyoxyethylene decyl ether, polyoxyethylene octyl ether, polyoxyethylene bisphenol-A Ether, polyoxyethylene glycerin ether, polyoxyethylene nonylphenyl ether, polyoxyethylene benzyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene phenol ether, polyoxy having 6-30 carbon atoms in the alkyl group Ethylene alkyl cyclohexyl ether, polyoxyethylene β-naphthol ether, polyoxyethylene castor ether, polyoxyethylene hydrogenated castor ether; Polyoxyethylene lauryl ester, polyoxyethylene stearyl ester, polyoxyethylene oleyl ester; And polyoxyethylene laurylamine, polyoxyethylene stearylamine, and polyoxyethylene tallowamine. Moreover, polypropylene glycol is mentioned as a polyoxypropylene type (POP) surfactant. In addition, as a copolymer of a polyoxyethylene-based (POE) compound and a polyoxypropylene-based (POP)-based compound, polyoxyethylene-polyoxypropylene copolymer, polyoxyethylene-polyoxypropylene decanyl ether copolymer, polyoxyethylene -Polyoxypropylene undecanyl ether copolymer, polyoxyethylene-polyoxypropylene dodecanyl ether copolymer, polyoxyethylene-polyoxypropylene tetradecanyl ether copolymer, polyoxyethylene-polyoxypropylene 2-ethylhexyl ether copolymer Copolymer, polyoxyethylene-polyoxypropylene lauryl ether copolymer, polyoxyethylene-polyoxypropylene stearyl ether copolymer, glycerin addition polyoxyethylene-polyoxypropylene copolymer, ethylenediamine addition polyoxyethylene-polyoxypropylene And copolymers. These may be used alone or in combination of two or more.

The polyoxyethylene-based (POE) compound, the polyoxypropylene-based (POP) compound, and a surfactant thereof, may be included at 10 ^-9 to 10% by weight based on the total weight of the texture etching solution composition of the crystalline silicon wafer, preferably Is 10 ^-6 to 1% by weight, more preferably 0.00001 to 0.1% by weight. When the content falls within the above range, variations in texture quality for each location may be reduced when texturing the surface of the crystalline silicon wafer.

The texture etchant composition of the crystalline silicon wafer according to the present invention is appropriately adopted according to specific needs, and water is added to control the overall composition, so that the remaining amount of the total composition is occupied by water. Preferably, the components are adjusted to have the aforementioned content range.

The type of water is not particularly limited, but is preferably deionized distilled water, and more preferably, as the deionized distilled water for semiconductor processes, the specific resistance value is 18 kPa/cm or more.

The texture etchant composition of the crystalline silicon wafer of the present invention can be applied to all common etching processes, such as dip, spray, and sheetfed etching processes.

The present invention provides a method for texture etching a crystalline silicon wafer using the texture etchant composition of the crystalline silicon wafer.

The method of texture etching a crystalline silicon wafer is a step of depositing a crystalline silicon wafer on the texture etchant composition of the crystalline silicon wafer of the present invention, or spraying the texture etchant composition of the crystalline silicon wafer of the present invention onto the crystalline silicon wafer. Steps, or both.

The number of times of deposition and spraying is not particularly limited, and when both deposition and spraying are performed, the order is not limited.

The step of immersion, spraying or immersion and spraying can be performed at a temperature of 50 to 100° C. for 30 seconds to 60 minutes.

The texture etching method of the crystalline silicon wafer of the present invention as described above is not economical in terms of initial production and process cost because there is no need to introduce a separate air rating equipment for supplying oxygen, and a uniform pyramid in a simple process It allows the formation of structures.

Hereinafter, preferred embodiments are provided to help the understanding of the present invention, but these examples are merely illustrative of the present invention and do not limit the scope of the appended claims, and the embodiments are within the scope and technical scope of the present invention. It is apparent to those skilled in the art that various changes and modifications to the present invention are possible, and it is natural that such modifications and modifications belong to the appended claims.

Manufacturing example

Sodium salts of carboxymethylcellulose (C-1 to C-7) and cellulose (C-8) having various molecular weights were prepared.

< Polymerization Measurement>

However, since the glucan-based compound is a polymer, it is difficult to measure the molecular weight. Therefore, molecular weight was indirectly confirmed through viscosity. The trend line was calculated as a commercially available product (product of Aldrich) having the molecular weight, viscosity and polymerization degree as shown in Table 1 below, and the molecular weight was determined by substituting the viscosity of the prepared C-1 to C-8 on the trend line. The trend line and the substitution results of C-1 to C-8 are shown in FIG. 1. The red straight line in the graph represents the viscosity range of the corresponding glucan compound.

According to Figure 1, it can be seen that the polymerization degree of C-1 to C-5, C-8, ref-1 and ref-2 is 1,000 or less.

division Molecular weight (g/mol) Viscosity(cp) Degree of polymerization ref-1 (Aldrich) 90000 17.2 144 ref-2 (Aldrich) 250000 199.3 516 ref-3 (Aldrich) 750000 712 1500

Example And Comparative example

The remaining amount of water was added to the components and contents shown in Table 2 below to prepare an etchant composition for texture of a crystalline silicon wafer.

division
(weight%) alkali
compound Glucan
compound Cyclic compounds Annular
Polymer water Kinds content Kinds Degree of substitution content Kinds content Kinds content Example 1 KOH 2 C-1 0.5-0.7 0.04 - - - - Balance Example 2 KOH 2 Ref-1 0.7 0.05 - - - - Balance Example 3 KOH 2 C-2 0.8-0.9 0.06 - - - - Balance Example 4 KOH 2 C-3 0.8-0.9 0.04 - - - - Balance Example 5 KOH 2 Ref-2 0.7 0.04 - - - - Balance Example 6 KOH 2 Ref-2' 0.9 0.04 - - - - Balance Example 7 KOH 2 Ref-2" 1.2 0.04 - - - - Balance Example 8 KOH 2 C-4 0.65-0.9 0.04 - - - - Balance Example 9 KOH 2 C-4' 1-1.2 0.04 - - - - Balance Example 10 KOH 2 C-5 0.8-0.9 0.04 - - - - Balance Example 11 KOH 2 C-2 0.8-0.9 0.55 - - - - Balance Example 12 KOH 2 C-5 0.8-0.9 0.05 NMP 4 PNVP 0.00001 Balance Example 13 KOH 2 C-2 0.8-0.9 0.06 NMP
AEP 3.8
0.2 - - Balance Example 14 KOH 2 C-3 0.8-0.9 0.04 NMP
GBL 3.8
0.2 PNAM 0.00001 Balance Comparative Example 1 KOH 2 C-2' 0.3-0.4 0.04 - - - - Balance Comparative Example 2 KOH 2 C-5' 1.3~1.5 0.04 - - - - Balance Comparative Example 3 KOH 2 C-5" 1.5-1.7 0.04 - - - - Balance Comparative Example 4 KOH 2 C-6 0.7~0.8 0.04 - - - - Balance Comparative Example 5 KOH 2 Ref-3 0.9 0.04 - - - - Balance Comparative Example 6 KOH 2 C-7 0.7~0.8 0.04 - - - - Balance Comparative Example 7 KOH 2 C-6 0.7~0.8 0.04 NMP
GBL 3.8
0.2 PNAM 0.00001 Balance Comparative Example 8 KOH 2 Ref-3 0.9 0.06 NMP
GBL 3.8
0.2 - - Balance Comparative Example 9 KOH 2 C-7 0.7~0.8 0.04 NMP
GBL 3.8
0.2 PNAM 0.00001 Balance Comparative Example 10 KOH 2 C-6' 0.3-0.4 0.04 - - - - Balance Comparative Example 11 KOH 2 Ref-3' 1.3~1.5 0.04 - - - - Balance Comparative Example 12 KOH 2 C-7' 1.5-1.7 0.04 - - - - Balance C-2': C-2 has a similar molecular weight, but a different degree of substitution.
C-4': C-4 has a similar molecular weight, but a different degree of substitution.
C-5', C-5": C-5 is similar in molecular weight, but has a different degree of substitution and has a polymerization degree of 1,000 or less.
Ref-1': Ref-1 is similar in molecular weight, but has a different degree of substitution, and has a polymerization degree of 1,000 or less.
Ref-2', Ref-2": A compound having a similar molecular weight to Ref-2, but with a different degree of substitution.
Ref-3': Ref-3 is similar in molecular weight, but has a different degree of substitution, and has a polymerization degree of 1,500 or more.
C-6': C-6 has a similar molecular weight, but a different degree of substitution.
C-7': C-7 has a similar molecular weight, but a different degree of substitution.

Experimental Example

The single crystal silicon wafers were etched by immersing each in the etchant composition for texture of the crystalline silicon wafers of Examples and Comparative Examples. At this time, the texture conditions were a temperature of 80°C and a time of 20 minutes.

One. Texture Uniformity evaluation

The uniformity of the texture was evaluated using an optical microscope and SEM, and the pyramid size was evaluated using SEM, and the results were shown in Table 2 and FIG. 2 (Example 3), FIG. 3 (Example 7), and FIG. 4 (Comparative Example 1). It is shown in.

◎: Wafer front pyramid formation

○: part of the wafer is not formed in a pyramid

(Pyramid structure non-formation degree less than 5%)

△: Wafer part pyramid not formed

(Pyramid structure microforming degree 5-50%)

Х: Wafer pyramid not forming

(Pyramid non-formation degree more than 90%)

2. Texture Reflectance evaluation

The texture reflectance was measured when the average reflectance when irradiating light having a wavelength range of 400 to 800 nm using ultraviolet rays, and the results are shown in Table 3.

division pyramid
Formation degree reflectivity
At 600nm(%) Example 1 ○ 11.37 Example 2 ◎ 10.56 Example 3 ◎ 10.74 Example 4 ◎ 10.62 Example 5 ◎ 10.89 Example 6 ◎ 11.08 Example 7 ○ 12.23 Example 8 ◎ 10.85 Example 9 ○ 12.34 Example 10 ○ 11.08 Example 11 ○ 11.98 Example 12 ◎ 10.61 Example 13 ◎ 10.86 Example 14 ◎ 10.67 Comparative Example 1 △ 15.97 Comparative Example 2 △ 14.67 Comparative Example 3 X 19.77 Comparative Example 4 △ 14.35 Comparative Example 5 X 18.12 Comparative Example 6 X 19.27 Comparative Example 7 △ 13.74 Comparative Example 8 △ 14.63 Comparative Example 9 △ 14.35 Comparative Example 10 △ 15.78 Comparative Example 11 X 18.38 Comparative Example 12 X 19.54

Referring to Table 3 and FIG. 2, it can be seen that the etchant composition for texture of the silicon wafers of Examples 2 to 6, Examples 8 and 12 to 14 has a very good pyramid formation degree on the entire surface of the single crystal silicon wafer. In addition, it can be seen that the texture of the wafer exhibits a low reflectance value of about 10 to 12%.

In addition, it was confirmed that the pyramid was formed at a high magnification through 3D optical microscopy or SEM analysis to confirm that the pyramid was formed.

However, in FIG. 3, the etchant composition for the texture of the silicon wafers of Examples 1, 7 and 9 to 11 may form a pyramid on the front surface of a single crystal silicon wafer, but it can be seen that pyramids are crushed in a very part.

However, in the etchant composition for the texture of the wafer of Comparative Examples 1 to 12, the pyramids are formed on the entire surface of the wafer as shown in FIG. 4 (Comparative Example 1), but due to excessive etching, pyramids are crushed in many parts, or in some cases, pyramids. It was confirmed that the degree of pyramid formation was poor because of the presence of the unformed portion.

Claims (18)

Alkali compound, a water-soluble glucan-based compound having a polymerization degree of 1,000 or less, a polymer substituted with a cyclic compound having 4 to 10 carbon atoms containing at least one nitrogen atom, and a polymer and a cyclic compound,
The water-soluble glucan-based compound is polymerized with an alkyl carboxyl group having 1 to 3 carbon atoms or glucose substituted with a metal salt thereof,
The degree of substitution of the alkyl carboxyl group or its metal salt of the water-soluble glucan-based compound is 0.8 to 0.9
The degree of substitution is the number of the alkyl carboxyl groups or metal salt substituents per molecule of the glucose contained in the water-soluble glucan-based compound, the texture etching solution composition of a crystalline silicon wafer.
The method according to claim 1, wherein the glucan-based compound is at least one selected from the group consisting of carboxymethylcellulose, carboxyethylcellulose, carboxypropylcellulose and metal salts thereof, the texture etching solution composition of the crystalline silicon wafer.
The method according to claim 2, wherein the unit of the substituted cellulose is cellobiose, the texture etchant composition of the crystalline silicon wafer.
The method according to claim 1, The glucan-based compound is included in 10 ^-9 to 0.5% by weight relative to the total 100% by weight of the etching solution composition, the texture etching solution composition of a crystalline silicon wafer.
The method according to claim 1, The alkali compound is at least one selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium and tetrahydroxyethylammonium, the texture etching solution composition of the crystalline silicon wafer.
delete The method according to claim 1, wherein the monomer further comprises at least one of oxygen and sulfur atoms in the ring structure, the texture etchant composition of the crystalline silicon wafer.
The method according to claim 1, wherein the monomer is N-vinylpyrrolidone, N-acryloyl morpholine, N-vinyl succinimide, N-acryloxy succinimide, N-vinyl caprolactam, N-vinyl carbazole and A texture etchant composition for a crystalline silicon wafer, which is at least one selected from the group consisting of N-acryloylpyrrolidine.
The method according to claim 1, wherein the polymer has a weight average molecular weight of 1,000 to 1,000,000, the etchant composition of the texture of the crystalline silicon wafer.
The method according to claim 1, wherein the polymer has a boiling point of 100 °C or more, the texture etching liquid composition of the crystalline silicon wafer.
The method according to claim 1, wherein the polymer has a solubility parameter of Hansen is 6 to 15, the texture etching solution composition of a crystalline silicon wafer.
The method according to claim 1, wherein the polymer is 10 to ¹² to 1% by weight based on the total weight of the etchant composition, the texture etchant composition of the crystalline silicon wafer.
delete The method according to claim 1, wherein the cyclic compound has a boiling point of 100 °C or more, the texture etching liquid composition of the crystalline silicon wafer.
The method according to claim 1, wherein the cyclic compound has a solute solubility parameter of 6 to 15, the etchant composition of the crystalline silicon wafer texture.
A method for etching a texture of a crystalline silicon wafer using the etching solution composition according to any one of claims 1 to 5, 7 to 12 and 14 to 15.
The etching method according to claim 16, comprising spraying the etchant composition at a temperature of 50 to 100° C. for 30 seconds to 60 minutes.
The etching method of claim 16, wherein the wafer is immersed in the etching solution composition at a temperature of 50 to 100° C. for 30 seconds to 60 minutes.

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