JP2014534630A - Texture etching solution composition for crystalline silicon wafer and texture etching method - Google Patents

Abstract

The present invention relates to a texture etching solution composition and a texture etching method for a crystalline silicon wafer. When a fine pyramid structure is formed on the surface of a crystalline silicon wafer by including a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having a nitrogen atom is polymerized, It is possible to form a pyramid having a specific structure capable of increasing the light efficiency by minimizing the quality deviation of the texture by position and reducing the reflectance. [Selection] Figure 1

Description

  The present invention relates to a texture etching composition for a crystalline silicon wafer and a texture etching method, which can improve the light efficiency by minimizing the quality deviation of the texture of each position on the surface of the crystalline silicon wafer.

  In recent years, solar cells that are rapidly spreading are electronic elements that directly convert solar energy, which is clean energy, into electricity as a next-generation energy source, based on a P-type silicon semiconductor in which boron is added to silicon, It is composed of a PN junction semiconductor substrate having an N-type silicon semiconductor layer formed by diffusing phosphorus on its surface.

  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 and move freely inside the semiconductor, When entering the electric field formed by such a PN junction, electrons (−) reach the N-type semiconductor and holes (+) reach the P-type semiconductor. If an electrode is formed on the surface of a P-type semiconductor and an N-type semiconductor to allow electrons to flow to an external circuit, a current is generated, but solar energy is converted into electric energy by such a principle. 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. For this purpose, the reflectance is reduced and the light absorption amount is maximized. There must be. In consideration of such points, the surface of the silicon wafer for solar cells constituting the PN junction semiconductor substrate is formed in a fine pyramid structure, and the antireflection film is processed. The surface of a silicon wafer textured in a fine pyramid structure increases the performance of solar cells, i.e. efficiency, by reducing the reflectance of incident light having a wide wavelength band and increasing the intensity of pre-absorbed light be able to.

  US Pat. No. 4,137,123 describes a method for texturing a silicon wafer surface into a fine pyramid structure, in which 0-75% by volume ethylene glycol, 0.05-50% by weight potassium hydroxide, and the rest A silicon texture etching solution in which 0.5 to 10% by weight of silicon is dissolved in an anisotropic etching solution containing an amount of water is disclosed. However, this etchant can cause poor pyramid formation, increase light reflectivity, and reduce efficiency.

  In addition, EP 0477424 provides a texture etching method in which oxygen is supplied to a texture etching solution in which silicon is dissolved in ethylene glycol, potassium hydroxide, and the remaining amount of water, that is, a texture etching method involving an air rating step. It is disclosed. However, this etching method not only causes poor pyramid formation, but also increases the light reflectivity and decreases the efficiency, and has the disadvantage that a separate air rating device is required.

  Korean Patent No. 10-0180621 discloses a texture mixed in a proportion of 0.5 to 5% potassium hydroxide solution, 3 to 20% by volume isopropyl alcohol, and 75 to 96.5% by volume deionized water. An etching solution is disclosed, and US Pat. No. 6,451,218 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, and this must be added in the texturing process, it is not economical in terms of productivity and cost. As a result, the temperature gradient of the etching solution is generated, and the quality deviation of the texture for each position on the silicon wafer surface becomes large, and the uniformity may be impaired.

US Pat. No. 4,137,123 European Patent No. 0477424 Korean Registered Patent No. 10-0180621

  The present invention forms a pyramid having a specific structure capable of increasing the light efficiency and reducing the reflectance by minimizing the quality deviation of the texture by position when forming the fine pyramid structure on the surface of the crystalline silicon wafer. An object of the present invention is to provide a texture etching solution composition for a crystalline silicon wafer.

  Another object of the present invention is to provide a texture etching solution composition for a crystalline silicon wafer that does not require the addition of a separate etching solution component and the application of an aerating process during the etching process.

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

  1. A texture etching liquid composition for a crystalline silicon wafer, comprising a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having at least one nitrogen atom is polymerized.

  2. In the item 1, the texture monomer composition for crystalline silicon wafer, wherein the monomer further has at least one of oxygen and sulfur atoms in the ring structure.

  3. In the item 1, the monomer is a group consisting of N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylsuccinimide, N-acryloxysuccinimide, N-vinylcaprolactam, N-vinylcarbazole, and N-acryloylpyrrolidine. A texture etching solution composition for a crystalline silicon wafer, which is at least one selected from the group consisting of:

  4). In the item 1, the texture etching liquid composition for crystalline silicon wafer, wherein the polymer has a weight average molecular weight of 1,000 to 1,000,000.

  5. In the item 1, the polymer is a crystalline silicon wafer texture etching solution composition having a boiling point of 100 ° C. or higher.

6). The texture etchant composition for crystalline silicon wafers according to item 1, wherein the polymer is contained in an amount of 10 ⁻¹² to 1% by weight based on the total weight of the etchant composition.

  7). The texture etchant composition for crystalline silicon wafers according to item 1, further comprising an alkaline compound.

  8). The texture etchant composition for crystalline silicon wafers according to item 1, further comprising a polysaccharide.

  9. In the item 7, the alkaline compound is one or more selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium, and tetrahydroxyethylammonium. Texture etchant composition.

  10. In the item 8, the texture of the crystalline silicon wafer, 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. Etching solution composition.

  11. In the above item 8, the polysaccharide is cellulose, dimethylaminoethylcellulose, diethylaminoethylcellulose, ethylhydroxyethylcellulose, methylhydroxyethylcellulose, 4-aminobenzylcellulose, triethylaminoethylcellulose, cyanoethylcellulose, ethylcellulose, methylcellulose, carboxymethylcellulose, carboxyethylcellulose, Hydroxyethyl cellulose, hydroxypropyl cellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran , Dextransolf A texture etching solution composition for a crystalline silicon wafer, which is at least one glucan compound selected from the group consisting of sodium sate, saponin, glycogen, zymosan, lentinan, schizophyllan, and metal salts thereof.

  12 The texture etching solution composition for crystalline silicon wafers according to item 1, further comprising a sulfonate anionic surfactant.

  13. In item 12, the sulfonate anionic surfactant is PEG-12 dimethicone sulfosuccinate disodium, dioctyl sulfosuccinate sodium, sodium dodecylbenzene sulfonate, lauryl sulfosuccinate disodium, PEG-12 dimethicone sulfosuccinate dipotassium, dihexyl. A crystalline silicon wafer that is at least one selected from the group consisting of sodium sulfosuccinate, sodium dilauryl sulfosuccinate, potassium dioctyl sulfosuccinate, potassium dihexyl sulfosuccinate, potassium dilauryl sulfosuccinate, and dipotassium lauryl sulfosuccinate Texture etchant composition.

  14 The texture etchant composition for crystalline silicon wafers according to item 1, further comprising a silica compound.

15. In the item 14, the silica compound is fine powder silica; colloidal silica dispersion stabilized with Na ₂ O; colloidal silica dispersion stabilized with K ₂ O; colloidal silica dispersion stabilized with an acidic liquid Liquid: colloidal silica dispersion stabilized with NH ₃ ; colloidal silica dispersion stabilized with one or more organic solvents selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone, and methyl isobutyl ketone A texture etching liquid composition for a crystalline silicon wafer, which is at least one selected from the group consisting of: liquid; liquid sodium silicate; liquid potassium silicate; and liquid lithium silicate.

16. In the item 14, the texture etching solution composition for a crystalline silicon wafer, wherein the silica compound is contained in an amount of 10 ⁻⁵ to 10 wt% with respect to the total weight of the etching solution composition.

  17. A method for etching a crystalline silicon wafer using the etching solution composition according to any one of items 1 to 16.

  18. 18. The etching method according to item 17, wherein the etching solution composition is sprayed at a temperature of 50 to 100 ° C. for 30 seconds to 60 minutes.

  19. 18. The etching method according to item 17, wherein the wafer is deposited in the etching solution composition at a temperature of 50 to 100 ° C. for 30 seconds to 60 minutes.

  According to the texture etching liquid composition and the texture etching method of the crystalline silicon wafer of the present invention, the quality deviation of the texture according to the position on the crystalline silicon wafer surface is minimized, that is, the uniformity of the texture is improved and sunlight is improved. The pyramid formed according to the present invention has a structure in which the inclined surface of the pyramid is inserted in the inner direction of the pyramid. By further reducing the rate and having a reflectance of 10% or less, the light efficiency can be dramatically increased.

  Since it is not necessary to introduce a separate etching solution component in the texture process and it is not necessary to introduce an air rating device, the quality and productivity can be improved, and the process cost is economical.

FIG. 1 is an SEM photograph showing the texture of a single crystal silicon wafer etched using the crystalline silicon wafer texture etchant composition of Example 1. FIG. 2 is an SEM photograph showing the texture of a single crystal silicon wafer etched using the etching solution composition for texture of a crystalline silicon wafer of Example 13. FIG. 3 is an SEM photograph showing the texture of a single crystal silicon wafer etched using the texture etchant composition for crystalline silicon wafers of Comparative Example 1.

  The present invention forms a fine pyramid structure on the surface of a crystalline silicon wafer by including a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having at least one nitrogen atom is polymerized. In particular, a textured etchant composition and a texture for a crystalline silicon wafer capable of forming a pyramid having a specific structure capable of increasing the light efficiency while minimizing the quality deviation of the texture by position and reducing the reflectance. The present invention relates to an etching method.

  Hereinafter, the present invention will be specifically described.

  The texture etchant composition for crystalline silicon wafers of the present invention comprises a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having at least one nitrogen atom is polymerized. .

  The polymer included in the present invention can control the difference in etching rate with respect to the silicon crystal direction, thereby minimizing texture quality deviation by preventing excessive etching by alkaline compounds. By rapidly reducing the amount of hydrogen bubbles generated, the occurrence of bubble stick phenomenon is also suppressed.

  In particular, when the polymer included in the present invention is used as an etching solution, the formed pyramid has a structure in which the inclined surface of the pyramid is inserted into the inside of the pyramid. The structure in which the inclined surface is inserted into the inside has a lower reflectance than the conventional general pyramid structure. Therefore, when the etching solution of the present invention is used, the reflectance can be lowered to 10% or less, so that the light efficiency can be increased.

  The polymer included in the present invention is formed by polymerizing a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having at least one nitrogen heteroatom. In addition to nitrogen, the monomer may further have at least one oxygen atom or sulfur atom or both in the ring structure. Specific examples of such monomers include N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylsuccinimide, N-acryloxysuccinimide, N-vinylcaprolactam, N-vinylcarbazole, N-acryloylpyrrolidine. It may be one or more selected from the group consisting of and the like.

  The polymer included in the present invention has a weight average molecular weight of 1,000 to 1,000,000, and not only can the reflectance be lowered by increasing the base angle of the pyramid, but also a single crystal silicon wafer. It is preferable from the point that a uniform pyramid can be formed on the entire surface.

  In addition, the polymer included in the present invention preferably has a boiling point as high as 100 ° C. or higher from the viewpoint that the amount used can be reduced, and more preferably 150 to 400 ° C.

  In one embodiment, the polymer included in the present invention has a Hansen solubility parameter (HSP; δp) of 6 to 15 and is compatible with other components contained in the etching solution composition. From the aspect, it is preferable.

The polymer contained in the present invention may be present in an amount of 10 ⁻¹² to 1% by weight with respect to the total weight of the etching solution composition. If the content is within the above range, the effect of controlling the difference in the etching rate with respect to the crystal direction of silicon is maximized, and this is preferable in order to form a pyramid structure in which the boundary surface is embedded.

  The polymer included in the present invention can be used by mixing 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 contained in the texture etching liquid composition of the crystalline silicon wafer, and is either a protic or aprotic polar solvent. Either of these can be used.

  Protic polar solvents include 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 Examples include ether compounds such as monobutyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether; alcohol compounds such as propanol, butanol, isopropanol, tetrahydrofurfuryl alcohol, ethylene glycol, and propylene glycol. Examples of the aprotic polar solvent include amide compounds such as N-methylformamide and N, N-dimethylformamide; sulfoxide compounds such as dimethyl sulfoxide and sulfolane; phosphate compounds such as triethyl phosphate and tributyl phosphate. These can be used alone or in admixture of two or more.

  The etching solution composition according to the present invention may further contain a silica compound.

  In the present invention, the silica compound serves as a kind of mask that is physically adsorbed on the surface of the crystalline silicon wafer, whereby the surface of the crystalline silicon wafer can have a fine pyramid shape. This is effective because the wafer surface has a uniform textured shape.

Examples of the silica compound that can be used in the present invention include a powder type, a colloidal dispersion type, and a liquid metal silicate compound. Specifically, fine powder silica; colloidal silica dispersion stabilized with Na ₂ O; colloidal silica dispersion stabilized with K ₂ O; colloidal silica dispersion stabilized with acidic liquid; stable with NH ₃ Colloidal silica dispersion liquid; colloidal silica dispersion liquid stabilized with one or more organic solvents selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone, and methyl isobutyl ketone; liquid sodium silicate Examples include liquid potassium silicate; and liquid lithium silicate, and these can be used alone or in admixture of two or more.

The silica compound may be present in an amount of 10 ⁻⁵ to 10% by weight, preferably 10 ⁻⁴ to 1% by weight, based on the total weight of the textured etchant composition of the crystalline silicon wafer.

  If the content is within the above range, a fine pyramid can be more easily formed on the surface of the crystalline silicon wafer.

  The etching solution composition according to the present invention may further include an alkaline compound, a polysaccharide and the like.

  The alkaline compound is a component that etches the surface of the crystalline silicon wafer, and any alkaline compound that is usually used in the art can be used without limitation. Usable alkaline compounds include potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium, tetrahydroxyethylammonium and the like, among which potassium hydroxide and sodium hydroxide are preferred. These can be used alone or in admixture of two or more.

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

  A polysaccharide is a saccharide in which two or more monosaccharides form a polymer by a glycosidic bond, and prevents excessive etching and acceleration of etching by an alkaline compound, thereby forming a uniform fine pyramid. In addition, the hydrogen bubbles generated by the etching are rapidly detached from the surface of the silicon wafer to prevent the bubble stick phenomenon.

  Examples of the polysaccharide include a glucan compound, a fructan compound, a mannan compound, a galactan compound, or a metal salt thereof, of which a glucan compound and its Metal salts (eg, alkali metal salts) are preferred. These can be used alone or in admixture of two or more.

  Glucan compounds include cellulose, dimethylaminoethylcellulose, diethylaminoethylcellulose, ethylhydroxyethylcellulose, methylhydroxyethylcellulose, 4-aminobenzylcellulose, triethylaminoethylcellulose, cyanoethylcellulose, ethylcellulose, methylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose, hydroxy Propylcellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran, dextran sulfate Na Examples thereof include thorium, saponin, glycogen, zymosan, lentinan, schizophyllan, and 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 present in an amount of 10 ^{−9 to} 0.5 wt% based on the total weight of the textured etchant composition of the crystalline silicon wafer, and should be 10 ^{−6 to} 0.1 wt%. preferable. When the content is within the above range, excessive etching and acceleration of etching can be effectively prevented. When the content is more than 0.5% by weight, the etching rate by the alkali compound is rapidly decreased, so that it becomes difficult to form a desired fine pyramid.

  Optionally, the crystalline silicon wafer texture etchant composition of the present invention may further comprise a sulfonate anionic surfactant. Sulfonate-based anionic surfactants form uniform fine pyramids by preventing excessive etching and acceleration of etching by alkaline compounds, and quickly detach hydrogen bubbles generated by etching from the silicon wafer surface. It is a component that prevents the bubble stick phenomenon. And it has detergency and improves the appearance of the wafer surface after the texturing process by removing impurities on the silicon wafer surface.

  The type of the sulfonate anionic surfactant is not particularly limited. For example, disodium PEG-12 dimethicone sulfosuccinate, sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, disodium lauryl sulfosuccinate, disodium PEG-12 dimethicone sulfosuccinate. Examples include potassium, sodium dihexyl sulfosuccinate, sodium dilauryl sulfosuccinate, potassium dioctyl sulfosuccinate, potassium dihexyl sulfosuccinate, potassium dilauryl sulfosuccinate, dipotassium lauryl sulfosuccinate. These can be used alone or in admixture of two or more.

  The sulfonate anionic surfactant may be present in an amount of 0.000001 to 1% by weight, based on 100% by weight of the total amount of the crystalline silicon wafer texture etchant composition, and 0.00001 to 0.1% by weight. % Is preferable, and 0.0001 to 0.1% by weight is more preferable. If content is in the said range, uniform pyramid formation and detergency performance can be exhibited effectively.

  Optionally, the crystalline silicon wafer texture etchant composition of the present invention comprises a fatty acid or a metal salt thereof; and a polyoxyethylene-based (POE) compound, a polyoxypropylene-based (POP) compound, and a copolymer thereof. It may further contain one or more additives selected from the group consisting of surfactants.

  Fatty acids and their metal salts are used with polysaccharides to prevent excessive etching by alkaline compounds to form a uniform fine pyramid. At the same time, hydrogen bubbles generated by etching are rapidly detached from the silicon wafer surface. It is a component that prevents the occurrence of the bubble stick phenomenon.

  The fatty acid is a carboxylic acid of a hydrocarbon chain containing a carboxy group, specifically, acetic acid, propionic acid, butyric acid, valeric acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid. , Palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, olein Examples include acid, elaidic acid, erucic acid, nervonic acid and the like. The fatty acid metal salt includes an ester product of the fatty acid and a metal salt such as NaOH or KOH. These can be used alone or in admixture of two or more.

The fatty acid and its metal salt may be present in an amount of 10 ⁻⁹ to 10% by weight, preferably 10 ⁻⁶ to 1% by weight, based on the total weight of the crystalline silicon wafer texture etchant composition. . If the content is within the above range, excessive etching can be effectively prevented.

A polyoxyethylene-based (POE) compound, a polyoxypropylene-based (POP) compound, and a copolymer thereof are surfactants having a hydroxy group, and hydroxy ions [OH ⁻ ] in a texture etching solution composition. In addition to reducing the difference in the etching rate with respect to the Si ₁₀₀ direction and the Si ₁₁₁ direction by adjusting the activity level, the wettability of the crystalline silicon wafer surface is improved to quickly desorb hydrogen bubbles generated by the etching. This is a component that prevents the bubble stick phenomenon from occurring.

  Polyoxyethylene (POE) surfactants include polyoxyethylene glycol, polyoxyethylene glycol methyl ether, polyoxyethylene monoallyl ether, polyoxyethylene neopentyl ether, polyethylene glycol mono (tristyrylphenyl) ether, poly Oxyethylene 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 octyl phenyl ether, polyoxyethylene phenol ether, polyoxyethylene alkyl cyclohexyl ether having 6 to 30 carbon atoms in alkyl group, polyoxyethylene β-naphthol ether, polyoxyethylene caster Ether (polyoxyethylene castor ether), polyoxyethylene hydrogenated castor ether; polyoxyethylene lauryl ester, polyoxyethylene stearyl ester, polyoxyethylene oleyl ester; polyoxyethylene lauryl amine, polyoxyethylene stearylamine And polyoxyethylene tallowamine. Moreover, polypropylene glycol is mentioned as a polyoxypropylene type (POP) surfactant. Moreover, as a copolymer of a polyoxyethylene type | system | group (POE) compound and a polyoxypropylene type | system | group (POP) compound, a polyoxyethylene-polyoxypropylene copolymer, a polyoxyethylene-polyoxypropylene decanyl ether copolymer is used. , Polyoxyethylene-polyoxypropylene undecanyl ether copolymer, polyoxyethylene-polyoxypropylene dodecanyl ether copolymer, polyoxyethylene-polyoxypropylene tetradecanyl ether copolymer, polyoxyethylene-polyoxy Propylene 2-ethylhexyl ether copolymer, polyoxyethylene-polyoxypropylene lauryl ether copolymer, polyoxyethylene-polyoxypropylene stearyl ether copolymer, glycerin-added polyoxy Styrene - polyoxypropylene copolymer, ethylene diamine addition type polyoxyethylene - polyoxypropylene copolymers, and the like. These can be used alone or in admixture of two or more.

The polyoxyethylene-based (POE) compound, the polyoxypropylene-based (POP) compound, and the surfactant which is a copolymer thereof are 10 ^{− based on} the total weight of the texture etching solution composition of the crystalline silicon wafer. ^It can be present in an amount of ⁹ to 10% by weight, preferably 10 ⁻⁶ to 1% by weight, more preferably ^0.00001 to 0.1% by weight. If the content is within the above range, the texture quality deviation by position can be reduced during the texture of the crystalline silicon wafer surface.

  The crystalline silicon wafer texture etching solution composition according to the present invention is appropriately selected according to the specific application, and then added with water to adjust the overall composition. Water occupies. Preferably, the ingredients are adjusted to have the aforementioned content range.

  The type of water is not particularly limited, but is preferably deionized distilled water, more preferably deionized distilled water for semiconductor processes, and more preferably a non-resistance value of 18 MΩ / cm or more.

  The crystalline silicon wafer texture etchant composition of the present invention comprising the above-described components includes, in particular, a polymer having a substituent of a cyclic compound containing a heteroelement, thereby providing a crystalline silicon wafer surface. It is possible to minimize the quality deviation of the texture by position, that is, to improve the uniformity of the texture to maximize the amount of absorption of sunlight, and to reduce the light reflectance to increase the light efficiency. The shape of the pyramid can also reduce the reflectivity by having a structure in which the inclined surface is inserted into the inside of the pyramid. Further, it is not necessary to introduce a separate etching solution component during the texture etching process, and it is not necessary to introduce an air rating device, which is advantageous in terms of productivity and cost.

  The crystalline silicon wafer texture etchant composition of the present invention can be applied to all normal etching processes, for example, deep, spray, and single wafer etching processes.

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

  The crystalline silicon wafer texture etching method includes the step of depositing the crystalline silicon wafer in the crystalline silicon wafer texture etching composition of the present invention, or the crystalline silicon wafer texture etching composition of the present invention is crystalline. Spraying the silicon wafer, or both of the two steps.

  The number of times of deposition and spraying is not particularly limited, and the order of deposition and spraying is not limited.

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

  The crystalline silicon wafer texture etching method of the present invention as described above does not require the introduction of a separate air rating device for supplying oxygen, is economical in terms of initial production and process costs, and is simple. A uniform fine pyramid structure can be formed depending on the process. Moreover, the shape of the pyramid can also reduce reflectivity by having a structure in which the inclined surface is inserted into the inside of the pyramid.

  In order that the present invention may be better understood, the following preferred examples are given, but these examples are merely illustrative of the invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the scope of the technical idea, and such changes and modifications are within the scope of the appended claims. Of course it belongs.

[Examples 1 to 20 and Comparative Examples 1 to 6]
The remaining amount of water was added to the components and composition ratios (% by weight) shown in Table 1 below to prepare an etching solution composition for crystalline silicon wafer texture.

Experimental Example Single crystal silicon wafers were etched by being immersed in the texture etching solution compositions for crystalline silicon wafers of Examples 1 to 20 and Comparative Examples 1 to 6, respectively. At this time, the texture conditions were a temperature of 80 ° C. and a time of 20 minutes.

  The uniformity and the reflectance of the texture formed with each composition were measured, and the results are shown in Table 2.

  FIG. 1 is a SEM photograph showing the texture of a single crystal silicon wafer etched using the crystalline etchant composition for crystalline silicon wafers of Example 1, and FIG. FIG. 3 is a SEM photograph showing the texture of a single crystal silicon wafer etched using the texture silicon wafer texture etchant composition, and FIG. 3 shows the crystal silicon wafer texture etch composition of Comparative Example 1 It is the SEM photograph which showed the texture of the single crystal silicon wafer etched using.

  The uniformity of the texture was evaluated using a visual evaluation (digital camera), an optical microscope and an SEM, and the size of the pyramid was evaluated using the SEM.

A: A pyramid is formed on the entire surface of the wafer. O: A pyramid is not formed on a part of the wafer (the degree that the pyramid structure was not formed: less than 5%).
Δ: Pyramid is not formed on a part of the wafer (degree of pyramid structure not formed: 5 to 50%)
×: Pyramid is not formed on the wafer (degree of pyramid not formed: 90% or more)

  The texture reflectance measured the average reflectance at the time of irradiating the light which has a wavelength range of 400-800 nm using an ultraviolet-ray.

  Referring to Table 2, it was found that the silicon wafer texture etchant compositions of Examples 1 to 20 were very excellent in the degree of pyramid formation on the entire surface of the single crystal silicon wafer. In particular, referring to FIGS. 1 and 2, it was found that the pyramid shapes of Examples 1 and 13 had a structure in which an inclined surface was inserted into the inside. Due to such texture uniformity and pyramid shape, it was found that the silicon wafer texture formed by the examples exhibited low reflectance values of less than 10%.

  However, in the etching solution compositions for texture of wafers of Comparative Examples 1 and 2, a pyramid is formed on the entire wafer surface, and referring to FIG. 3 (Comparative Example 1), it is found that the shape of the pyramid is general. It was. Accordingly, it has been found that the reflectance is as high as 10% or more.

Claims (19)

  A texture etching liquid composition for a crystalline silicon wafer, comprising a polymer in which a monomer substituted with a cyclic compound having 4 to 10 carbon atoms having at least one nitrogen atom is polymerized.   The texture etchant composition for a crystalline silicon wafer according to claim 1, wherein the monomer further has at least one of oxygen and sulfur atoms in a ring structure.   The monomer is selected from the group consisting of N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylsuccinimide, N-acryloxysuccinimide, N-vinylcaprolactam, N-vinylcarbazole, and N-acryloylpyrrolidine. The texture etching liquid composition of the crystalline silicon wafer of Claim 1 which is a seed | species or more.   The texture etching liquid composition for a crystalline silicon wafer according to claim 1, wherein the polymer has a weight average molecular weight of 1,000 to 1,000,000.   The texture etching solution composition for a crystalline silicon wafer according to claim 1, wherein the polymer has a boiling point of 100 ° C. or higher. The texture etching liquid composition of the crystalline silicon wafer according to claim 1, wherein the polymer is contained in an amount of ^10-12 to 1% by weight based on the total weight of the etching liquid composition.   The texture etching liquid composition of the crystalline silicon wafer of Claim 1 which further contains an alkaline compound.   The texture etching liquid composition of the crystalline silicon wafer of Claim 1 which further contains polysaccharide.   The crystalline silicon wafer according to claim 7, wherein the alkaline compound is one or more selected from the group consisting of potassium hydroxide, sodium hydroxide, ammonium hydroxide, tetrahydroxymethylammonium, and tetrahydroxyethylammonium. Texture etchant composition.   9. The crystalline silicon wafer according to claim 8, wherein the polysaccharide is at least one selected from the group consisting of glucan compounds, fructan compounds, mannan compounds, galactan compounds, and metal salts thereof. Texture etchant composition.   The polysaccharide is cellulose, dimethylaminoethylcellulose, diethylaminoethylcellulose, ethylhydroxyethylcellulose, methylhydroxyethylcellulose, 4-aminobenzylcellulose, triethylaminoethylcellulose, cyanoethylcellulose, ethylcellulose, methylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose, hydroxypropyl Cellulose, alginic acid, amylose, amylopectin, pectin, starch, dextrin, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, dextran, dextran sulfate sodium , Sa The texture etchant composition for crystalline silicon wafers according to claim 8, which is at least one glucan compound selected from the group consisting of ponin, glycogen, zymosan, lentinan, schizophyllan, and metal salts thereof.   The texture etching liquid composition of the crystalline silicon wafer of Claim 1 which further contains a sulfonate type | system | group anionic surfactant.   The sulfonate anionic surfactants include disodium PEG-12 dimethicone sulfosuccinate, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, disodium lauryl sulfosuccinate, dipotassium PEG-12 dimethicone sulfosuccinate, dihexyl sulfosuccinate sodium, The crystalline silicon wafer according to claim 12, which is at least one selected from the group consisting of sodium lauryl sulfosuccinate, potassium dioctyl sulfosuccinate, potassium dihexyl sulfosuccinate, potassium dilauryl sulfosuccinate, and dipotassium lauryl sulfosuccinate. Texture etchant composition.   The texture etching liquid composition of the crystalline silicon wafer of Claim 1 which further contains a silica compound. The silica compound includes fine powder silica; colloidal silica dispersion stabilized with Na ₂ O; colloidal silica dispersion stabilized with K ₂ O; colloidal silica dispersion stabilized with acidic liquid; NH ₃ Stabilized colloidal silica dispersion; colloidal silica dispersion stabilized with one or more organic solvents selected from the group consisting of ethyl alcohol, propyl alcohol, ethylene glycol, methyl ethyl ketone, and methyl isobutyl ketone; liquid silicic acid The texture etching liquid composition of the crystalline silicon wafer of Claim 14 which is 1 or more types selected from the group which consists of sodium; liquid potassium silicate; and liquid lithium silicate. The texture etching liquid composition of the crystalline silicon wafer of Claim 14 with which the said silica compound is contained 10 ^<-5 > -10weight% with respect to the total weight of an etching liquid composition.   A texture etching method for a crystalline silicon wafer, using the etching solution composition according to claim 1.   The etching method according to claim 17, wherein the etching solution composition is sprayed at a temperature of 50 to 100 ° C. for 30 seconds to 60 minutes.   The etching method according to claim 17, wherein the wafer is deposited in the etching solution composition at a temperature of 50 to 100 ° C. for 30 seconds to 60 minutes.

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