KR20130002258A - Texture etching solution composition and texture etching method of crystalline silicon wafers - Google Patents

Abstract

PURPOSE: A texture etching solution composition is provided to increase sunlight absorption and light efficiency by improving the uniformity of a texture per location on the surface of a crystalline silicon. CONSTITUTION: A texture etching solution composition for a crystalline silicon wafer comprises 0.1-20 weight% of an alkali compound, 0.1-50 weight% of a cyclic compound, 10^(-9) ∼ 0.5 weight% of a polysaccharides, and residual water. The alkali compound is one or more selected from potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxy methyl ammonium, and tetrahydroxy ethyl ammonium. The texture etching method of the crystalline silicon wafer comprises a step of depositing and/or spraying a crystalline wafer with the texture etching composition.

Description

Texture etching liquid 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 etching solution composition and a texture etching method of the crystalline silicon wafer that can improve the light efficiency by minimizing the texture quality variation of each position on the surface of the crystalline silicon wafer.

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, and diffuse phosphorus on its surface based on P-type silicon semiconductors containing boron in silicon. It consists of the PN junction semiconductor substrate in which the N type silicon semiconductor layer was formed.

When light such as sunlight is irradiated onto a substrate on which an electric field is formed by a PN junction, electrons (-) and holes (+) in the semiconductor are excited to move freely inside the semiconductor, and the electric field generated by the PN junction Upon entering, 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 an external circuit, current is generated. Solar energy is converted into electrical energy based on the same principle. Therefore, in order to increase the conversion efficiency of solar energy, the electrical output per unit area of the PN junction semiconductor substrate should be maximized. For this purpose, the reflectance should be low and the light absorption amount should be maximized. In view of this point, the surface of the solar cell silicon wafer constituting the PN junction semiconductor substrate is formed into a fine pyramid structure and the antireflection film is treated. The surface of the silicon wafer textured with the fine pyramid structure increases the intensity of the light absorbed by lowering the reflectance of incident light having a wide wavelength band, thereby improving the performance of the solar cell.

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 weight in an anisotropic etching solution containing 0-75% by volume of ethylene glycol, 0.05-50% by weight of potassium hydroxide and the remaining amount of water. A silicon texture etching solution in which% silicon is dissolved is disclosed. However, this etchant can cause pyramid formation defects to increase the light reflectance and cause a decrease in efficiency.

In addition, European Patent No. 0477424 discloses a texture etching method of supplying oxygen to a texture etching solution in which silicon is dissolved in ethylene glycol, potassium hydroxide and residual water, that is, performing an air rating process. However, this etching method has a disadvantage in that it causes poor pyramid formation, which leads to an increase in light reflectivity and a decrease in efficiency, and requires the installation of a separate air rating equipment.

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

Patent Document 1: US Patent No. 4,137,123 Patent Document 2: European Patent No. 0477424 Patent Document 3: Korean Registered Patent No. 0180621

In the present invention, in forming a fine pyramid structure on the surface of a crystalline silicon wafer, the texture etching solution composition of the crystalline silicon wafer capable of minimizing the quality variation of the texture for each location to increase the light efficiency and increase the number of treatments for the unit usage. The purpose is to provide.

In addition, an object of the present invention is to provide a texture etching liquid composition of a crystalline silicon wafer that does not require the addition of a separate etching liquid component and the application of an air rating process during the etching process.

Another object of the present invention is to provide a texture etching method using the texture etching liquid composition of the crystalline silicon wafer.

1. 0.1-20% by weight of alkali compound; 0.1-50% by weight of the cyclic compound; Polysaccharides 10 ^-9 to 0.5% by weight; And a residual amount of water.

2. The composition according to 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.

3. In the above 1, wherein the cyclic compound has a boiling point of 100 ℃ or more texture etching liquid composition of the crystalline silicon wafer.

4. In the above 3, wherein the cyclic compound is Hansen solubility parameter of 6 to 15 texture etching liquid composition of the crystalline silicon wafer.

5. The method according to the above 1, wherein the polysaccharide is at least one selected from the group consisting of glucan-based compounds, fructan-based compounds, mannan-based compounds, galactan-based compounds and metal salts of the etching solution of the crystalline silicon wafer.

6. In the above 5, the polysaccharide is cellulose, dimethylaminoethyl cellulose, diethylaminoethyl cellulose, ethyl hydroxyethyl cellulose, methyl hydroxyethyl cellulose, 4-aminobenzyl cellulose, triethylaminoethyl cellulose, cyanoethyl cellulose , Ethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ- 1 type selected from the group consisting of cyclodextrin, hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran, dextransulfate sodium, saponin, glycogen, zymoic acid, lentinan, sizopinan and metal salts thereof Crystalline silicone web which is the above glucan type compound Texture etching liquid composition of the buffer.

7. In the above 5, the polysaccharide has an average molecular weight of 5,000 to 1,000,000 texture etching liquid composition of a crystalline silicon wafer.

8. according to the above 1, the texture etching liquid composition of the crystalline silicon wafer further comprising a water-soluble polar solvent.

9. In the above 8, the water-soluble polar solvent is 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, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propanol, butanol, isopropanol, tetrahydroperfuryl alcohol, ethylene glycol, propylene glycol And texture etching solution composition of at least one crystalline silicon wafer selected from the group consisting of N-methylformamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, triethyl phosphate and tributyl phosphate.

10. In the above 8, the water-soluble polar solvent is a texture etching solution composition of the crystalline silicon wafer containing 0.1 to 30% by weight relative to the total 100% by weight of the cyclic compound.

11. The texture etching solution composition of claim 1, further comprising at least one selected from the group consisting of fatty acids and metal salts thereof.

12. The texture etching solution of crystalline silicon wafer further comprising at least one surfactant selected from the group consisting of polyoxyethylene-based (POE) compounds, polyoxypropylene-based (POP) compounds and copolymers thereof Composition.

13. according to the above 1, fine powder silica; Colloidal silica solution stabilized with Na ₂ O; Colloidal silica solution stabilized with K ₂ O; Colloidal silica solution stabilized with acid solution; Colloidal silica solution stabilized with NH ₃ ; Colloidal silica solution stabilized with at least one organic solvent selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone and methyl isobutyl ketone; Liquid sodium silicate; Liquid potassium silicate; And at least one silica compound selected from the group consisting of liquid lithium silicate.

14. The texture etching method of the crystalline silicon wafer comprising the step of depositing, spraying or depositing and spraying the crystalline silicon wafer with the texture etching liquid composition of any one of the above 1 to 13.

15. The method of claim 14, the deposition, spraying or deposition and spraying is a texture etching method of a crystalline silicon wafer is carried out for 30 seconds to 60 minutes at a temperature of 50 to 100 ℃.

According to the texture etching liquid composition and the texture etching method of the crystalline silicon wafer of the present invention, the quality variation of the texture of each position on the surface of the crystalline silicon wafer is minimized, that is, the uniformity of the texture is improved to maximize the absorption of sunlight and lower the light reflectance. The light efficiency can be improved.

In addition, the present invention can increase the number of processing for the unit usage compared to the conventional texture etching solution composition, there is no need to add a separate etching solution components during the texture process and do not need to introduce an air rating equipment to improve the quality and productivity It can be improved and economic in terms of process cost.

1 is a 3D optical micrograph showing the surface of a single crystal silicon wafer texture-etched with the texture etching solution composition of the crystalline silicon wafer of Example 11 of the present invention,
2 is a SEM photograph showing the surface of a single crystal silicon wafer textured etched with the texture etching liquid composition of the crystalline silicon wafer of Example 11 of the present invention.

The present invention relates to a texture etching liquid composition of a crystalline silicon wafer and a method of etching the texture of a crystalline silicon wafer using the same.

Hereinafter, the present invention will be described in detail.

The texture etching solution composition of the crystalline silicon wafer of the present invention is an alkali compound; Cyclic compounds; Polysaccharides; And water in an optimal content.

More specifically, the alkali compound 0.1 to 20% by weight; 0.1-50% by weight of the cyclic compound; Polysaccharides 10 ^-9 to 0.5% by weight; And residual water.

An alkali compound is a component which etches the surface of a crystalline silicon wafer, The kind is not specifically limited. For example, potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium, tetrahydroxyethylammonium, etc. are mentioned, Among these, potassium hydroxide and sodium hydroxide are preferable. These can be used individually or in mixture of 2 or more types.

The alkali compound is preferably included in an amount of 0.1 to 20% by weight, and more preferably 1 to 5% by weight, based on 100% by weight of the total amount of the texture etching solution composition of the crystalline silicon wafer. When the content falls within the above range, the silicon wafer surface can be etched.

The cyclic compound may be a cyclic hydrocarbon having 4-10 carbon atoms; And a heterocyclic hydrocarbon having 4 to 10 carbon atoms, including one or more heteroatoms of N, O, or S, wherein the wettability of the surface of the crystalline silicon wafer is improved to prevent overetching by an alkali compound. By minimizing the quality variation of the texture by preventing it, it is also a component that can prevent the bubble stick phenomenon from occurring by rapidly reducing the amount of hydrogen bubbles generated by etching. In addition, the boiling point can be used in a small amount compared to isopropyl alcohol is conventionally used as well as increase the number of treatment for the same amount of use.

It is preferable that a boiling point of a cyclic compound is high as 100 degreeC or more, More preferably, it is 150-400 degreeC. At the same time, it is preferable that the cyclic compound has a Hansen solubility parameter (HSP) of 6 to 15 in terms of compatibility with other components included in the etching liquid composition.

The cyclic compound is not particularly limited as long as it satisfies the boiling point and the solubility parameter of Hansen. Examples thereof include piperazine, morpholine, pyridine, piperidine, piperidone, pyrrolidine, pyrrolidone, Imidazolidinone type, furan type, aniline type, toluidine type, amine type, lactone type, carbonate type, carbazole type compound, etc. are mentioned. 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) morpho Pauline, N-acetylmorpholine, N-formylmorpholine, N-methylmorpholine-N-oxide; Methylpyridine; N-methylpiperidine, 3,5-dimethylpiperidine, N-ethylpiperidine, N- (2-hydroxyethyl) piperidine; N-vinylpiperidone, N-vinylmethylpiperidone, N-vinylethylpiperidone, N-acryloylpiperidone, 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-pyrroli 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, caprolactam; 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, caprolactone; Ethylene carbonate, propylene carbonate; N-vinyl carbazole, N-acryloyl carbazole, etc. are mentioned, These can be used individually or in mixture of 2 or more types.

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 amount of the texture etching solution composition of the crystalline silicon wafer. If the content falls within the above range, uniformity may be improved by effectively improving the wettability of the silicon wafer surface to minimize texture quality variation.

The cyclic compound 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 etching solution composition of the crystalline silicon wafer, and both proton or aprotic polar solvents can be used.

As a proton 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 compounds such as diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether and dipropylene glycol monomethyl ether; Alcohol compounds such as propanol, butanol, isopropanol, tetrahydrofurfuryl alcohol, ethylene glycol, propylene glycol, and the like. System compounds; Sulfoxide compounds such as dimethyl sulfoxide and sulfolane; Phosphate type compounds, such as a triethyl phosphate and a tributyl phosphate, etc. are mentioned. These can be used individually or in mixture of 2 or more types.

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 cyclic compound.

In particular, the present invention is characterized by including the polysaccharide in an optimum content.

Polysaccharide (polysaccharide) is a sugar in which two or more monosaccharides are glycosidic bonds to make a large molecule, and prevents overetching and accelerated etching by alkaline compounds to form a uniform fine pyramid and at the same time the hydrogen bubbles generated by etching It is a component that prevents bubble stick phenomenon by quickly falling from the silicon wafer surface.

Examples of the polysaccharides include glucan compounds, fructan compounds, mannan compounds, galactan compounds, or metal salts thereof. Among them, glucan compounds and metal salts thereof (e.g., Alkali metal salts) are preferred. These can be used individually or in mixture of 2 or more types.

Examples of the glucan compound include cellulose, dimethylaminoethyl cellulose, diethylaminoethyl cellulose, ethyl hydroxyethyl cellulose, methyl hydroxyethyl cellulose, 4-aminobenzyl cellulose, triethylaminoethyl cellulose, cyanoethyl cellulose, ethyl cellulose, Methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydrate Oxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran, dextransulfate sodium, saponin, glycogen, zymoic acid, lentinan, sizopinean or metal salts thereof.

The polysaccharide may have an average molecular weight of 5,000 to 1,000,000, preferably 50,000 to 200,000.

The polysaccharide may be included in an amount of 10 ^-9 to 0.5% by weight based on 100% by weight of the total amount of the texture etching solution composition of the crystalline silicon wafer, and preferably 10 ^-6 to 0.1% by weight. If the content falls within the above range, it is possible to effectively prevent over-etching and etching acceleration. If the content is more than 0.5% by weight, it is difficult to form the desired fine pyramid by drastically lowering the etching rate by the alkali compound.

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

Fatty acids and their metal salts are used in conjunction with polysaccharides to prevent overetching by alkali compounds, forming a uniform fine pyramid and at the same time quickly dropping the hydrogen bubbles generated by etching from the surface of the silicon wafer to prevent the occurrence of bubble sticking. It is an ingredient to say.

Fatty acids are carboxylic acids of hydrocarbon chains containing carboxyl groups, specifically acetic acid, propionic acid, butyric acid, valeric acid, enantiic 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, Oleic acid, elideic acid, erucic acid, nerbonic acid, and the like. In addition, the metal salt of a fatty acid may include an ester reactant of the above fatty acid with a metal salt such as NaOH or KOH. These can be used individually or in mixture of 2 or more types.

The fatty acid and its metal salt may be included in the amount of 10 ^-9 to 10% by weight, preferably 10 ^-6 to 1% by weight, based on 100% by weight of the total amount of the texture etching solution composition of the crystalline silicon wafer. When the content falls within the above range, over-etching can be effectively prevented.

Polyoxyethylene-based (POE) compounds, polyoxypropylene-based (POP) compounds and copolymers thereof are surfactants having a hydroxyl group By controlling the activity of hydroxy ions [OH ⁻ ] in the texture etchant composition, not only the difference in etching rate between the Si ₁₀₀ and Si ₁₁₁ directions is reduced, but also the wettability of the surface of the crystalline silicon wafer is improved to produce It also prevents bubble sticks from occurring by quickly dropping hydrogen bubbles.

As polyoxyethylene type (POE) surfactant, polyoxyethylene glycol, polyoxyethylene glycol methyl ether, polyoxyethylene monoallyl ether, polyoxyethylene neopentyl ether, polyethylene glycol mono (tristyrylphenyl) ether, 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 Polyoxyethylene having 6 to 30 carbon atoms in ether, polyoxyethylene glycerin ether, polyoxyethylene nonylphenyl ether, polyoxyethylene benzyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene phenol ether, alkyl group Ethylene alkylcyclohexyl ether, polyoxyethylene (beta) -naphthol ether, polyox Ethylene castor ether (polyoxyethylene castor ether), polyoxyethylene hydrogenated castor ether (polyoxyethylene hydrogenated castor ether); Polyoxyethylene lauryl ester, polyoxyethylene stearyl ester, polyoxyethylene oleyl ester; Polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene tallowamine, etc. are mentioned. Moreover, polypropylene glycol is mentioned as polyoxypropylene system (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 air Copolymer, polyoxyethylene-polyoxypropylene lauryl ether copolymer, polyoxyethylene-polyoxypropylene stearyl ether copolymer, glycerin addition polyoxyethylene-polyoxypropylene copolymer, ethylenediamine addition polyoxyethylene-polyoxypropylene And copolymers. These can be used individually or in mixture of 2 or more types.

The polyoxyethylene-based (POE) compound, the polyoxypropylene-based (POP) compound, and a copolymer thereof and a surfactant thereof may be included in amounts of 10 ^-9 to 10% by weight based on 100% by weight of the texture etching solution composition of the crystalline silicon wafer. Preferably, it is 0.00001 to 0.1% by weight, more preferably 10 ^-6 to 1% by weight. When the content falls within the above range, it is possible to reduce the variation of the texture quality by location when the surface of the crystalline silicon wafer surface is textured.

In addition, the silica compound is a component that physically adsorbs on the surface of the crystalline silicon wafer and serves as a kind of mask to make the surface of the crystalline silicon wafer into a fine pyramid shape.

Examples of the silica compound include powder, colloidal solution, or liquid metal silicate compounds. Specifically, fine powder silica; Colloidal silica solution stabilized with Na ₂ O; Colloidal silica solution stabilized with K ₂ O; Colloidal silica solution stabilized with acid solution; Colloidal silica solution stabilized with NH ₃ ; Colloidal silica solution stabilized with at least one organic solvent selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone and methyl isobutyl ketone; Liquid sodium silicate; Liquid potassium silicate; Liquid lithium silicate etc. can be mentioned, These can be used individually or in mixture of 2 or more types.

The silica compound may be included in an amount of 10 ^-9 to 10% by weight, preferably 10 ^-6 to 1% by weight, based on 100% by weight of the texture etching solution composition of the crystalline silicon wafer. If the content falls within the above range, it is possible to easily form a fine pyramid on the surface of the crystalline silicon wafer.

Water may be included in the remaining amount in the total 100% by weight of the texture etching solution composition of the crystalline silicon wafer.

Although the kind of water is not specifically limited, It is preferable that it is deionized distilled water, More preferably, it is preferable that the specific resistance value is 18 kW / cm or more as deionized distilled water for a semiconductor process.

Texture etching liquid composition of the crystalline silicon wafer of the present invention comprising the above components, in particular, by containing the polysaccharides with the optimal content in conjunction with the cyclic compound to minimize the quality variation of the texture of each position on the surface of the crystalline silicon wafer In other words, by improving the uniformity of the texture to maximize the absorption of sunlight and lower the light reflectance can increase the light efficiency. In addition, it is possible to increase the number of processing for the unit usage, there is no need to add a separate etching solution component during the texture etching process, there is no need to introduce the air rating equipment there is an advantage in terms of productivity and cost.

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

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

The texture etching method of the crystalline silicon wafer includes depositing, spraying or depositing and spraying the crystalline silicon wafer using the texture etching liquid composition of the crystalline silicon wafer of the present invention.

The number of depositions and sprays is not particularly limited, and the order of both deposition and spraying is not limited.

Deposition, spraying or depositing and spraying may be performed for 30 seconds to 60 minutes at a temperature of 50 to 100 ° C.

The texture etching method of the crystalline silicon wafer of the present invention as described above is not only economical in terms of initial production and processing cost but also requires no separate airrating equipment for supplying oxygen, Structure.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but these examples are merely illustrative of the present invention and are not intended to limit the scope of the appended claims. It is apparent to those skilled in the art that various changes and modifications can be made to the present invention, and such modifications and changes belong to the appended claims.

Example

Example  One

A texture etching solution composition of a crystalline silicon wafer was prepared by mixing 2% by weight of potassium hydroxide (KOH), 4% by weight of N-methylmorpholine (NMM), 0.001% by weight of alginic acid (AA) and the remaining amount of deionized distilled water.

Example  2-33, Comparative example  1-4

The same procedure as in Example 1, except that the same ingredients and contents as in Table 1 were used. Here, the content represents weight percent.

division Alkali compounds Annular
Compound / Solvent Polysaccharide fatty acid
/salt Interface
Active agent Silica
compound Kinds content Kinds content Kinds content Kinds content Kinds content Kinds content Example
One KOH 2 NMM 4 AA 0.001 - - - - - - Example
2 KOH 2 NMM 4 AANa 0.002 - - - - - - Example
3 KOH 2 NMM 4 CMC 0.001 - - - - - - Example
4 KOH 2 NMM 4 CMCNa 0.002 - - - - - - Example
5 KOH 2 NMM 4 DSNa 0.001 - - - - - - Example
6 KOH 2 NMP
4 CMCNa 0.002 - - - - - - Example
7 KOH 2 NMP
TP 4
0.2 CMCNa 0.002 - - - - - - Example
8 KOH 2 NMP
CTam 4
0.2 CMCNa 0.002 - - - - - - Example
9 KOH 2 NMP
AEP 3.8
0.2 AA 0.002 - - - - - - Example
10 KOH 2 NMP
GBL 3.8
0.2 AA 0.003 - - - - - - Example
11 KOH 2 NMP
GBL
TP 3.8
0.2
0.2 AA 0.003 - - - - - - Example
12 KOH 2 NMP
GBL
CTon 3.8
0.2
0.2 AA 0.003 - - - - - - Example
13 KOH 2 NMP
EC 3.8
0.2 AA 0.002 - - - - - - Example
14 KOH 2 NMP
PC 3.8
0.2 AA 0.003 - - - - - - Example
15 KOH 2 NMP
EC
PC 1.6
0.45
0.15 AA 0.002 - - - - - - Example
16 KOH 2 NMP
EC
PC 1.3
0.3
0.1 CMCNa 0.001 - - - - - - Example
17 KOH 2 NMP
EC
PC
TP 1.3
0.3
0.1
0.2 CMCNa 0.001 - - - - - - Example
18 KOH 2 NMP
EC
PC
CTam 1.3
0.3
0.1
0.2 CMCNa 0.001 - - - - - - Example
19 NaOH One NMP
EC
PC 1.3
0.2
0.2 CMCNa 0.002 - - - - - - Example
20 KOH 2 NMM
EC
PC 1.3
0.3
0.1 AA 0.003 - - - - - - Example 21 KOH 2 NVP 0.2 CMCNa 0.002 - - - - - - Example 22 KOH 2 NVP
TP 0.2
0.2 CMCNa 0.002 - - - - - - Example 23 KOH 2 NVP
CTon 0.2
0.2 CMCNa 0.002 - - - - - - Example
24 KOH 2 NMP
EC
PC 1.6
0.45
0.15 CMCNa 0.002 LANa 0.003 - - - - Example 25 KOH 2 NVP 0.2 CMCNa 0.002 LANa 0.003 Example
26 KOH 2 NMM
AEP 1.6
0.6 AA 0.003 - - PBE 0.001 - - Example
27 KOH 2 NMP
GBL 1.6
0.6 CMCNa 0.002 - - POE 0.001 - - Example
28 KOH 2 NMP
GBL 1.6
0.6 AA 0.003 - - - - FAQ 0.2 Example
29 KOH 2 NMM
AEP 1.6
0.4 CMCNa 0.002 - - - - SCS 0.2 Example
30 KOH 2 NMM
EC
PC 1.6
0.45
0.15 AA 0.003 LA 0.003 POE 0.001 - - Example
31 KOH 2 NMP
EC
PC 1.6
0.45
0.15 CMCNa 0.001 LANa 0.003 PBE 0.001 - - Example
32 KOH 2 NMM
EC
PC 1.6
0.45
0.15 AA 0.003 LA 0.003 POE 0.001 FAQ 0.2 Example
33 KOH 2 NMP
EC
PC 1.3
0.3
0.1 CMCNa 0.001 LANa 0.003 PBE 0.001 SCS 0.2 Comparative Example
One KOH 2 NMP
EC
PC 1.6
0.45
0.15 - - - - - - - - Comparative Example 2 KOH 2 NMP
EC
PC 1.6
0.45
0.15 AA 0.6 - - - - - - Comparative Example 3 KOH 2 - - AA 0.003 - - - - - - Comparative Example 4 KOH 2 NMP 51 AA 0.001 - - - - - - KOH: Potassium Hydroxide
NMM: N-methylmorpholine
NMP: N-methylpyrrolidone
AEP: N- (2-aminoethyl) piperazine
GBL: γ-butyrolactone
EC: ethylene carbonate
PC: propylene carbonate
NVP: N-vinylpyrrolidone
TP: triethyl phosphate
CTam: Caprolactam
CTon: Caprolactone
AA: alginic acid
AANa: Sodium Alginate
CMC: Carboxymethylcellulose
CMCNa: Sodium Carboxymethylcellulose
DSNa: dextran sulfate sodium
LANa: Sodium Laurate
LA: Lauric acid
PBE: polyoxyethylene benzyl ether
POE: polyoxyethylene octyl phenyl ether
SSS: Liquid Sodium Silicate
SCS: colloidal silica solution stabilized with Na ₂ O

Comparative example  5

A 1.5% by weight potassium hydroxide (KOH), 5% by weight isopropyl alcohol (IPA) and the remaining amount of deionized distilled water was mixed to prepare a texture etching solution composition of the crystalline silicon wafer.

Comparative example  6

In the same manner as in Comparative Example 5, ethylene glycol (EG) was used instead of isopropyl alcohol (IPA).

Comparative example  7

In the same manner as in Comparative Example 5, but instead of isopropyl alcohol (IPA) was used methyl diglycol (MDG).

Comparative example  8

The same procedure as in Comparative Example 5 except that monoethylamine (MEA) was used instead of isopropyl alcohol (IPA).

Test Example

The texture etching effect of the texture etching solution composition of the silicon wafers prepared in Examples and Comparative Examples was evaluated by the following method, and the results are shown in Table 2 below.

The single crystal silicon wafer substrate was immersed in the texture etching liquid composition of the prepared silicon wafer for 20 minutes at a temperature of 80 ° C.

(One) texture  Uniformity

Texture variation, that is, uniformity, formed on the surface of the etched single crystal silicon wafer substrate was visually observed using a digital camera, a 3D optical microscope, and a scanning electron microscope (SEM), and evaluated based on the following criteria. .

<Evaluation Criteria>

(Double-circle): Pyramid formation in all the wafer substrates.

(Circle): Pyramidal non-formation (less than 5% of unformed part) in a part of wafer substrate.

(Triangle | delta): Pyramid non-formation in 5 part of wafer substrates (5-50% of unformed part).

X: Pyramid unformed in most wafer substrates (90% or more of unformed parts).

(2) Pyramid average size (㎛)

The size of the fine pyramid formed on the surface of the textured etched single crystal silicon wafer substrate was measured using a scanning electron microscope (SEM). At this time, the size of the fine pyramid formed in the unit area was measured and expressed as their average value.

(3) Average reflectance (%)

The average reflectance when the surface of the texture-etched single crystal silicon wafer substrate was irradiated with light having a wavelength band of 400-800 nm using a UV spectrophotometer was measured.

division Texture Uniformity Pyramid Average Size (μm) Average reflectance (%) Example 1 ◎ 3 11.91 Example 2 ◎ 3 12.15 Example 3 ◎ 3 12.07 Example 4 ◎ 3 12.02 Example 5 ◎ 3 11.78 Example 6 ◎ 3 11.98 Example 7 ◎ 3 11.23 Example 8 ◎ 2 12.31 Example 9 ◎ 3 12.21 Example 10 ◎ 3 12.07 Example 11 ◎ 3 11.35 Example 12 ◎ 3 11.78 Example 13 ◎ 3 11.98 Example 14 ◎ 3 11.78 Example 15 ◎ 3 12.06 Example 16 ◎ 3 11.89 Example 17 ◎ 3 11.73 Example 18 ◎ 2 12.01 Example 19 ◎ 3 11.78 Example 20 ◎ 3 11.99 Example 21 ◎ 2 10.32 Example 22 ◎ 2 10.21 Example 23 ◎ 2 10.35 Example 24 ◎ 3 12.05 Example 25 ◎ 2 10.57 Example 26 ◎ 3 12.13 Example 27 ◎ 3 11.98 Example 28 ◎ 3 11.87 Example 29 ◎ 3 11.89 Example 30 ◎ 3 11.87 Example 31 ◎ 3 11.82 Example 32 ◎ 3 11.87 Example 33 ◎ 3 11.77 Comparative Example 1 ○ 6 12.56 Comparative Example 2 △ 5 20.12 Comparative Example 3 ○ 5 12.14 Comparative Example 4 △ 5 22.87 Comparative Example 5 ○ 5 13.22 Comparative Example 6 × 10 21.13 Comparative Example 7 Etching Discoloration Comparative Example 8 Etching Discoloration

As shown in Table 2, the alkali compound according to the present invention; Cyclic compounds; Polysaccharides; And when the texture is etched using the texture etching solution compositions of Examples 1 to 33 containing the optimum amount of water, the uniformity of the fine pyramids formed on the surface of the single crystal silicon wafer is small and the uniformity is excellent. Low light efficiency was also improved.

1 is a 3D optical micrograph showing the surface of the crystalline silicon wafer texture etched with the texture etching solution composition of Example 15, Figure 2 is a SEM photograph showing the surface of the texture etched crystalline silicon wafer. Through this, it can be seen that the fine pyramid is formed over the entire surface of the wafer so that the quality variation is small and the texture uniformity is improved.

On the other hand, Comparative Example 1, which does not include a polysaccharide, had a poor appearance of the textured silicon wafer substrate, and a portion of the pyramid was not present. In Comparative Example 2, which contained an excessive amount of polysaccharide, the etching rate was too slow to increase the reflectance. In Comparative Example 3, which does not include the cyclic compound, part of the pyramid was not observed similarly to Comparative Example 1, and Comparative Example 4, which contained the excess of the cyclic compound, was difficult to control the etching rate, so that the reflectance was low. It's high. In addition, the texture etching solution composition of Comparative Example 5 due to the low temperature of the isopropyl alcohol (IPA) due to the temperature gradient generated by the continuous input of the texture during the texture failure and cost more, The texture etchant composition showed significantly inferior characteristics in comparison with Examples in terms of texture uniformity and light reflectance. The texture etching solution compositions of Comparative Examples 7 and 8 exhibited a change with time in the etching solution composition itself when heated to the texture process temperature.

Claims (15)

0.1-20% by weight of alkaline compound; 0.1-50% by weight of the cyclic compound; Polysaccharides 10 ^-9 to 0.5% by weight; And a residual amount of water.
The texture etching solution composition of claim 1, wherein 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 liquid composition of Claim 1 in which a cyclic compound has a boiling point of 100 degreeC or more.
The texture etching solution composition of claim 3, wherein the cyclic compound has a Hansen solubility parameter of 6 to 15. 5.
The texture etching solution composition of claim 1, wherein the polysaccharide is at least one selected from the group consisting of a glucan compound, a fructan compound, a mannan compound, a galactan compound, and a metal salt thereof.
The method of claim 5, wherein the polysaccharide is cellulose, dimethylaminoethyl cellulose, diethylaminoethyl cellulose, ethyl hydroxyethyl cellulose, methyl hydroxyethyl cellulose, 4-aminobenzyl cellulose, triethylaminoethyl cellulose, cyanoethyl cellulose, ethyl Cellulose, methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin At least one glucan selected from the group consisting of hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran, dextransulfate sodium, saponin, glycogen, zymoic acid, lentinan, sizopinean and metal salts thereof Crystalline Silicone As A Compound Texture etching liquid composition of the wipers.
The texture etchant composition of claim 5, wherein the polysaccharide has an average molecular weight of 5,000 to 1,000,000.
The texture etchant composition of claim 1, further comprising a water soluble polar solvent.
The method of claim 8, wherein the water-soluble polar solvent is 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, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propanol, butanol, isopropanol, tetrahydrofurfuryl alcohol, ethylene glycol, propylene glycol, N -Texture etching solution composition of crystalline silicon wafer of at least one selected from the group consisting of -methylformamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, triethyl phosphate and tributyl phosphate.
The texture etching solution composition of claim 8, wherein the water-soluble polar solvent is included in an amount of 0.1 to 30 wt% based on 100 wt% of the total cyclic compound.
The texture etching solution composition of claim 1, further comprising at least one selected from the group consisting of fatty acids and metal salts thereof.
The texture etching solution composition of claim 1, further comprising at least one surfactant selected from the group consisting of polyoxyethylene-based (POE) compounds, polyoxypropylene-based (POP) compounds, and copolymers thereof.
The method of claim 1, further comprising: fine powder silica; Colloidal silica solution stabilized with Na ₂ O; Colloidal silica solution stabilized with K ₂ O; Colloidal silica solution stabilized with acid solution; Colloidal silica solution stabilized with NH ₃ ; Colloidal silica solution stabilized with at least one organic solvent selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone and methyl isobutyl ketone; Liquid sodium silicate; Liquid potassium silicate; And at least one silica compound selected from the group consisting of liquid lithium silicate.
A method of etching a crystalline silicon wafer comprising depositing, spraying or depositing and spraying the crystalline silicon wafer with the texture etching liquid composition of any one of claims 1 to 13.
The method of claim 14, wherein the deposition, spraying or deposition and spraying are performed at a temperature of 50-100 ° C. for 30 seconds to 60 minutes.

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