阅读说明：本技术 单晶硅片制绒方法 (Monocrystalline silicon piece texturing method ) 是由 龙维绪 苏晓东 黄洁 查嘉伟 于 2019-01-31 设计创作，主要内容包括：本发明公开了一种单晶硅片制绒方法,包括：S1、将单晶硅片浸没在碱溶液和第一制绒辅助溶液的混合溶液中进行抛光刻蚀,第一制绒辅助溶液包括绒面刻蚀剂、金属络合剂、第一表面活性剂、第一消泡剂中的一种或多种；S2、将抛光刻蚀后的单晶硅片浸没在碱溶液和第二制绒辅助溶液的混合溶液中进行制绒刻蚀,第二制绒辅助溶液包括绒面成核剂、pH调节剂、第二表面活性剂、第二消泡剂中的一种或多种。本发明通过引入制绒辅助溶液,仅需抛光刻蚀和制绒刻蚀两步工艺即可实现单晶硅片的制绒,大大减少了工艺时间,提高了生产效率；制绒过程中无需使用双氧水,大大减少了碱的耗量,降低了生产成本；降低了硅片表面绒面的反射率,绒面反射率能达到10％左右,硅片表面陷光性能更佳,从而提升了光电转换效率。(The invention discloses a monocrystalline silicon piece texturing method, which comprises the following steps: s1, immersing the monocrystalline silicon wafer in a mixed solution of an alkali solution and a first texturing auxiliary solution for polishing and etching, wherein the first texturing auxiliary solution comprises one or more of a texturing etching agent, a metal complexing agent, a first surfactant and a first defoaming agent; and S2, immersing the polished and etched monocrystalline silicon wafer into a mixed solution of an alkali solution and a second texturing auxiliary solution for texturing and etching, wherein the second texturing auxiliary solution comprises one or more of a texturing nucleating agent, a pH regulator, a second surfactant and a second defoaming agent. According to the invention, by introducing the texturing auxiliary solution, the texturing of the monocrystalline silicon wafer can be realized only by two processes of polishing etching and texturing etching, so that the process time is greatly reduced, and the production efficiency is improved; hydrogen peroxide is not needed in the texturing process, so that the consumption of alkali is greatly reduced, and the production cost is reduced; the reflectivity of the texture surface on the surface of the silicon wafer is reduced, the reflectivity of the texture surface can reach about 10%, and the light trapping performance of the surface of the silicon wafer is better, so that the photoelectric conversion efficiency is improved.)

1. A monocrystalline silicon piece texturing method is characterized by comprising the following steps:

s1, immersing the monocrystalline silicon wafer in a mixed solution of an alkali solution and a first texturing auxiliary solution for polishing and etching, wherein the first texturing auxiliary solution comprises one or more of a texturing etching agent, a metal complexing agent, a first surfactant and a first defoaming agent;

and S2, immersing the polished and etched monocrystalline silicon wafer into a mixed solution of an alkali solution and a second texturing auxiliary solution for texturing and etching, wherein the second texturing auxiliary solution comprises one or more of a texturing nucleating agent, a pH regulator, a second surfactant and a second defoaming agent.

2. The method for texturing a single crystal silicon wafer according to claim 1, wherein the step S1 specifically comprises:

immersing the monocrystalline silicon piece in a mixed solution of KOH or NaOH solution with the mass fraction of 1-3% and first texturing auxiliary solution with the volume fraction of 0.5-1.0%, and carrying out polishing and etching at the temperature of 75-80 ℃ for 2-3 min.

3. The method for texturing a single crystal silicon wafer according to claim 1, wherein the step S2 specifically comprises:

immersing the polished and etched monocrystalline silicon wafer in a KOH or NaOH solution with the mass fraction of 1-3% and a second texturing auxiliary solution with the volume fraction of 0.5-1.0%, and etching at the temperature of 80-85 ℃ for 5-6 min.

4. The monocrystalline silicon wafer texturing method according to claim 2, wherein the first texturing auxiliary solution comprises, by mass:

0.5 to 1 percent of suede etching agent;

2-5% of metal complexing agent;

0.05 to 0.08 percent of first surfactant;

0.01 to 0.02 percent of first defoaming agent;

and deionized water.

5. The method of texturing a single-crystal silicon wafer according to claim 4, wherein in the first texturing assisting solution:

the etching agent of the suede comprises one or more of sodium hypochlorite, amino triethanol and PEG 2000;

the metal complexing agent comprises one or more of ethylene diamine tetraacetic acid disodium salt, D L-malic acid, and imino disuccinic acid tetrasodium;

the first surfactant comprises one or more of betaine, fatty alcohol-polyoxyethylene ether and perfluorinated surfactant;

the first defoaming agent comprises one or more of a polyether defoaming agent and a polyether modified silicon defoaming agent.

6. The method of texturing a single-crystal silicon wafer according to claim 4, wherein the resistivity of the first texturing assisting solution is 15M Ω -cm or more.

7. The monocrystalline silicon wafer texturing method according to claim 3, wherein the second texturing assisting solution comprises, in mass fraction:

10-20% of suede nucleating agent;

3 to 6 percent of pH regulator;

0.05 to 0.08 percent of second surfactant;

0.01 to 0.02 percent of second defoaming agent;

and deionized water.

8. The method of texturing a single-crystal silicon wafer according to claim 7, wherein in the second texturing assisting solution:

the suede nucleating agent comprises one or more of N-hydroxymethyl acrylamide, hydroxyethyl cellulose, soybean lecithin, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer and polymaleic acid;

the pH regulator comprises a pH acid regulator and a pH alkali regulator;

the second suede surface active agent comprises one or more of a Gemini surface active agent, an alkyl glycoside novel surface active agent and an imidazoline amphoteric surface active agent;

the second defoaming agent comprises one or more of polydimethylsiloxane, a high alcohol type defoaming agent and a polyether modified silicon defoaming agent.

9. The method of texturing a single-crystal silicon wafer according to claim 7, wherein the resistivity of the second texturing assisting solution is 15M Ω -cm or more.

10. The method of claim 1, wherein the monocrystalline silicon wafer is a solar grade monocrystalline silicon wafer or an electronic grade monocrystalline silicon wafer.

Technical Field

The invention belongs to the technical field of silicon wafer texturing, and particularly relates to a monocrystalline silicon wafer texturing method.

Background

In the production of the crystalline silicon solar cell, a special concave-convex structure needs to be etched on the surface of a silicon wafer by using a special solution, the etching process is called texturing, and the etched special structure is called a textured structure. The texture structure can effectively reduce the reflectivity of the surface of the silicon wafer to light, thereby improving the photoelectric conversion efficiency of the solar cell.

For a single crystal silicon wafer, an alkali solution such as a potassium hydroxide solution, a sodium hydroxide solution, or the like is generally used for texturing. The key process for texturing the monocrystalline silicon wafer in the prior art comprises three steps:

1. polishing and etching: immersing a monocrystalline silicon piece in KOH or NaOH solution with the mass fraction of 1% -3%, wherein the etching temperature is 60-75 ℃, and the etching time is 3-4 min;

2. cleaning: immersing the polished and etched monocrystalline silicon wafer in KOH or NaOH with the mass fraction of 0.5-2% and hydrogen peroxide solution with the volume fraction of 5-10%, wherein the cleaning temperature is 60-75 ℃, and the cleaning time is 2-3 min;

3. texturing: immersing the cleaned monocrystalline silicon wafer in a mixed solution of KOH or NaOH with the mass fraction of 1-3% and a texturing auxiliary agent with the volume fraction of 0.5-2%, wherein the texturing temperature is 80-85 ℃, and the etching time is 7-10 min.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a monocrystalline silicon piece texturing method, which realizes the ultra-fast texturing of the monocrystalline silicon piece by simplifying the texturing process of the monocrystalline silicon piece.

In order to achieve the above object, an embodiment of the present invention provides the following technical solutions:

a monocrystalline silicon piece texturing method comprises the following steps:

s1, immersing the monocrystalline silicon wafer in a mixed solution of an alkali solution and a first texturing auxiliary solution for polishing and etching, wherein the first texturing auxiliary solution comprises one or more of a texturing etching agent, a metal complexing agent, a first surfactant and a first defoaming agent;

and S2, immersing the polished and etched monocrystalline silicon wafer into a mixed solution of an alkali solution and a second texturing auxiliary solution for texturing and etching, wherein the second texturing auxiliary solution comprises one or more of a texturing nucleating agent, a pH regulator, a second surfactant and a second defoaming agent.

As a further improvement of the present invention, the step S1 specifically includes:

immersing the monocrystalline silicon piece in a mixed solution of KOH or NaOH solution with the mass fraction of 1-3% and first texturing auxiliary solution with the volume fraction of 0.5-1.0%, and carrying out polishing and etching at the temperature of 75-80 ℃ for 2-3 min.

As a further improvement of the present invention, the step S2 specifically includes:

immersing the polished and etched monocrystalline silicon wafer in a KOH or NaOH solution with the mass fraction of 1-3% and a second texturing auxiliary solution with the volume fraction of 0.5-1.0%, and etching at the temperature of 80-85 ℃ for 5-6 min.

As a further improvement of the present invention, the first texturing auxiliary solution comprises, by mass:

0.5 to 1 percent of suede etching agent;

2-5% of metal complexing agent;

0.05 to 0.08 percent of first surfactant;

0.01 to 0.02 percent of first defoaming agent;

and deionized water.

As a further improvement of the present invention, in the first texturing auxiliary solution:

the etching agent of the suede comprises one or more of sodium hypochlorite, amino triethanol and PEG 2000;

the metal complexing agent comprises one or more of ethylene diamine tetraacetic acid disodium salt, D L-malic acid, and imino disuccinic acid tetrasodium;

the first surfactant comprises one or more of betaine, fatty alcohol-polyoxyethylene ether and perfluorinated surfactant;

the first defoaming agent comprises one or more of a polyether defoaming agent and a polyether modified silicon defoaming agent.

As a further improvement of the present invention, the first texturing auxiliary solution has a resistivity of 15M Ω · cm or more.

As a further improvement of the present invention, the second texturing auxiliary solution comprises, in mass fraction:

10-20% of suede nucleating agent;

3 to 6 percent of pH regulator;

0.05 to 0.08 percent of second surfactant;

0.01 to 0.02 percent of second defoaming agent;

and deionized water.

As a further improvement of the present invention, in the second texturing auxiliary solution:

the suede nucleating agent comprises one or more of N-hydroxymethyl acrylamide, hydroxyethyl cellulose, soybean lecithin, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer and polymaleic acid;

the pH regulator comprises a pH acid regulator and a pH alkali regulator;

the second suede surface active agent comprises one or more of a Gemini surface active agent, an alkyl glycoside novel surface active agent and an imidazoline amphoteric surface active agent;

the second defoaming agent comprises one or more of polydimethylsiloxane, a high alcohol type defoaming agent and a polyether modified silicon defoaming agent.

As a further improvement of the present invention, the second texturing auxiliary solution has a resistivity of 15M Ω · cm or more.

As a further improvement of the invention, the monocrystalline silicon wafer is a solar grade monocrystalline silicon wafer or an electronic grade monocrystalline silicon wafer.

The invention has the beneficial effects that:

according to the invention, by introducing the texturing auxiliary solution, the texturing of the monocrystalline silicon wafer can be realized only by two processes of polishing etching and texturing etching, so that the process time is greatly reduced, and the production efficiency is improved;

hydrogen peroxide is not needed in the texturing process, so that the consumption of alkali is greatly reduced, and the production cost is reduced;

the reflectivity of the texture surface on the surface of the silicon wafer is reduced, the reflectivity of the texture surface can reach about 10%, and the light trapping performance of the surface of the silicon wafer is better, so that the photoelectric conversion efficiency is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a detailed flow chart of the texturing method of a monocrystalline silicon wafer according to the present invention;

FIG. 2 is a SEM photograph showing a cross-section of a polished and etched single-crystal silicon wafer in example 1 of the present invention;

FIG. 3 is a surface SEM photograph of a etched single crystal silicon wafer after texturing in example 1 of the present invention;

FIG. 4 is a graph showing the reflectance of a single crystal silicon wafer after texturing in example 1 according to the present invention with a wavelength of 350nm to 1050 nm.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention discloses a monocrystalline silicon piece texturing method, wherein the monocrystalline silicon piece is a solar-grade monocrystalline silicon piece or an electronic-grade monocrystalline silicon piece and the like, and the texturing method comprises the following steps:

s1, immersing the monocrystalline silicon wafer in a mixed solution of an alkali solution and a first texturing auxiliary solution for polishing and etching, wherein the first texturing auxiliary solution comprises one or more of a texturing etching agent, a metal complexing agent, a first surfactant and a first defoaming agent;

and S2, immersing the polished and etched monocrystalline silicon wafer into a mixed solution of an alkali solution and a second texturing auxiliary solution for texturing and etching, wherein the second texturing auxiliary solution comprises one or more of a texturing nucleating agent, a pH regulator, a second surfactant and a second defoaming agent.

Preferably, the monocrystalline silicon piece texturing method specifically comprises the following steps:

polishing and etching: immersing the monocrystalline silicon piece in a mixed solution of KOH or NaOH solution with the mass fraction of 1-3% and first texturing auxiliary solution with the volume fraction of 0.5-1.0%, and carrying out polishing and etching at the temperature of 75-80 ℃ for 2-3 min.

The resistivity of the first texturing auxiliary solution is greater than or equal to 15M omega cm. The first texturing auxiliary solution can effectively remove particles, organic matters, metal impurities and the like remained on the surface of the silicon wafer, and simultaneously introduce more defects on the surface of the silicon wafer.

Etching by texturing: immersing the polished and etched monocrystalline silicon wafer in a KOH or NaOH solution with the mass fraction of 1-3% and a second texturing auxiliary solution with the volume fraction of 0.5-1.0%, and etching at the temperature of 80-85 ℃ for 5-6 min.

The second texturing auxiliary solution has a resistivity of 15M omega cm or more. And a pyramid suede structure with the size of 1-3 microns can be quickly formed on the surface of the silicon wafer through the second texturing auxiliary solution, the reflectivity is reduced to about 10%, and the formed suede is uniform and has no organic matter residue.

Preferably, the first texturing auxiliary solution comprises the following components in percentage by mass:

0.5 to 1 percent of suede etching agent;

2-5% of metal complexing agent;

0.05 to 0.08 percent of first surfactant;

0.01 to 0.02 percent of first defoaming agent;

and deionized water.

Wherein:

the etching agent of the suede comprises one or more of sodium hypochlorite, amino triethanol and PEG 2000;

the metal complexing agent comprises one or more of ethylene diamine tetraacetic acid disodium salt, D L-malic acid, and imino disuccinic acid tetrasodium;

the first surfactant comprises one or more of betaine, fatty alcohol-polyoxyethylene ether and perfluorinated surfactant;

the first defoaming agent comprises one or more of a polyether defoaming agent and a polyether modified silicon defoaming agent.

Preferably, the second texturing auxiliary solution comprises, in mass fraction:

10-20% of suede nucleating agent;

3 to 6 percent of pH regulator;

0.05 to 0.08 percent of second surfactant;

0.01 to 0.02 percent of second defoaming agent;

and deionized water.

Wherein:

the suede nucleating agent comprises one or more of N-hydroxymethyl acrylamide, hydroxyethyl cellulose, soybean lecithin, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer and polymaleic acid;

the pH regulator comprises a pH acid regulator and a pH alkali regulator;

the second suede surface active agent comprises one or more of a Gemini surface active agent, an alkyl glycoside novel surface active agent and an imidazoline amphoteric surface active agent;

the second defoaming agent comprises one or more of polydimethylsiloxane, a high alcohol type defoaming agent and a polyether modified silicon defoaming agent.

The following is a further description with reference to specific examples.