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Chemical corrosive liquid and applications thereof

A technology of chemical corrosion and corrosion solution, which is applied in chemical instruments and methods, surface etching compositions, crystal growth, etc., can solve the problems of high process cost, low parallel resistance of solar cells, and too small feature size of textured surface, etc., to achieve Effects of reducing light reflectance, improving anti-reflection performance, and increasing aspect ratio

Active Publication Date: 2020-05-12
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The problem with this technology is that it needs to remove metal particle contamination on the silicon wafer and additional treatment of metal-containing waste liquid, the process cost is high, and the feature size of the obtained texture is often too small, resulting in low parallel resistance of the final solar cell

Method used

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  • Chemical corrosive liquid and applications thereof
  • Chemical corrosive liquid and applications thereof
  • Chemical corrosive liquid and applications thereof

Examples

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preparation example Construction

[0026] The present invention does not have special requirement to the preparation method of described chemical etchant, directly MnO 2 Particles, HNO 3 , HF and H 2 O can be mixed evenly according to the concentration requirements.

[0027] The present invention also provides the application of the chemical etching solution described in the above technical solution in silicon wafer etching.

[0028] In the present invention, the application is preferably textured on the surface of silicon wafers; the silicon wafers are preferably polycrystalline silicon wafers; more preferably polycrystalline silicon wafers obtained by diamond wire cutting. In the present invention, the step of texturizing the silicon wafer preferably includes: corroding the silicon wafer in the chemical etching solution described in the above technical solution. In the present invention, the corrosion time is preferably less than 60 minutes. Corrosion process of the present invention, anti-genetic followi...

Embodiment 1

[0041] A MnO-containing 2 particulate HNO 3 / HF / H 2 O chemical etching solution, wherein, the MnO 2 Particles are powder particles below 10 μm, and their dosage in the chemical corrosion solution is 30g / L; the HNO 3 The concentration in the chemical etching solution is 8.5mol / L; the concentration of the HF in the chemical etching solution is 2.5mol / L.

[0042] The method for making texture on the surface of a polycrystalline silicon chip using the chemical etching solution comprises the following steps in order:

[0043] (1) Put the diamond wire-cut polysilicon wafer into the MnO-containing 2 particulate HNO 3 / HF / H 2 Take out after 180s corrosion in O chemical etching solution at room temperature;

[0044] (2) With 5.0wt.% NaOH / H 2 O alkali solution is taken out after corrosion treatment at room temperature for 15s to remove porous silicon;

[0045] (3) HF / HCl / H with HF concentration of 2.8mol / L and HCl concentration of 3.2mol / L 2 O solution was washed for 2 minutes...

Embodiment 2

[0048] A MnO-containing 2 particulate HNO 3 / HF / H 2 O chemical etching solution, wherein, the MnO 2 Particles are powder particles below 10 μm, and their content in the chemical corrosion solution is 30g / L; the HNO 3 The concentration in the chemical etching solution is 9.4mol / L; the concentration of the HF in the chemical etching solution is 1.1mol / L.

[0049] The method for making texture on the surface of a polycrystalline silicon chip using the chemical etching solution comprises the following steps in order:

[0050] (1) Put the diamond wire-cut polysilicon wafer into the MnO-containing 2 particulate HNO 3 / HF / H 2 Take out after 90s corrosion in O chemical etching solution at room temperature;

[0051] (2) With 2.0wt.% NaOH / H 2 O alkali solution is taken out after 40s corrosion treatment at room temperature to remove the porous silicon;

[0052] (3) HF / HCl / H with HF concentration of 2.0mol / L and HCl concentration of 3.5mol / L 2 O solution was washed for 5 minutes...

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Abstract

The invention provides a chemical corrosive liquid, and belongs to the technical field of silicon wafer etching. The chemical corrosive liquid comprises an HNO3 / HF / H2O solution of MnO2 particles. According to the invention, when the chemical corrosive liquid is used for etching a silicon wafer, MnO2 particles settle on the surface of the silicon wafer to play a role of a mask, so that the reactionof etching the silicon wafer by HNO3 / HF / H2O mainly occurs in the area among the MnO2 particles so as to increase the depth-to-width ratio of an etching pit and reduce the light reflectivity of the surface of the silicon wafer; and the silicon is oxidized into SiO2 at the contact position of the MnO2 particles and the silicon, the generated SiO2 is removed by HF, the exposed silicon contacts MnO2,the reaction is continued, MnO2 particles are gradually consumed, and the comprehensive effect of the reaction is to improve the antireflection performance of the textured surface, so that the high-performance textured surface with low reflectivity can be obtained on the surface of the polycrystalline silicon wafer, and the method has the advantages of simple process and low cost.

Description

technical field [0001] The invention relates to the technical field of silicon wafer etching, in particular to a chemical etching solution and its application in silicon wafer etching. Background technique [0002] It is an important means to improve the efficiency of silicon solar cells to prepare textured surfaces on the surface of silicon wafers to reduce light reflectivity. At present, the main methods for preparing texture on the surface of polycrystalline silicon wafers include conventional HNO 3 / HF / H 2 O acid velvet and new black silicon velvet. [0003] HNO 3 / HF / H 2 O texturing uses the isotropic corrosion of silicon wafers by acid to obtain a textured surface with an "etch pit" structure on the surface of polycrystalline silicon wafers. There is a thick damage layer on the surface of the mortar-cut polysilicon wafer, and the position with structural defects can be used as the reaction starting point of acid texturing, and the reflectivity of the obtained "cor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K13/08C30B33/10C30B29/06
CPCC09K13/08C30B29/06C30B33/10
Inventor 刘欢赵雷王文静
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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