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Additive for alkali polishing of monocrystalline silicon wafer and application of additive

A silicon wafer alkali and additive technology, applied in the direction of single crystal growth, single crystal growth, crystal growth, etc., can solve the problems of poor stability, low reflectivity, pyramid residue, etc., achieve electrical performance gain, high reflectivity, and improve efficiency Effect

Active Publication Date: 2021-11-19
CHANGZHOU SHICHUANG ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Alkali polishing is a relatively common technical means at present, but there are often the following problems in alkali polishing: 1) Pyramids will remain if the alkali polishing is not thorough; 2) The reflectivity of alkali polishing is difficult to improve, and the stability is poor; 3) Alkali polishing The resulting tower base is smaller
[0004] At present, additives are also used in the polishing liquid to improve the above-mentioned alkali polishing problems, but the existing alkali polishing additives mainly use polishing agents, chelating agents, and protective agents, and there are still the following problems: 1) The alkali polishing additives have poor stability and the validity period is 3 Within one month; 2) The tower base formed by polishing is small; 3) The flatness of the polished surface is poor, and the reflectivity is low

Method used

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  • Additive for alkali polishing of monocrystalline silicon wafer and application of additive
  • Additive for alkali polishing of monocrystalline silicon wafer and application of additive
  • Additive for alkali polishing of monocrystalline silicon wafer and application of additive

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Embodiment 1

[0041] Take 2.5L alkali throwing tank, add 2L water, raise the temperature to 65°C, then add 100mL of 48% NaOH, and add 30ml of the additive of the present invention after the temperature stabilizes (the formula is: 0.05wt% vanillin, 1wt% % polyphosphate, 3wt% disodium tetraacetate, 0.08wt% benzotriazole, and the balance is deionized water); after stirring evenly, remove the PSG silicon wafer and place it in a tank of NaOH and hydrogen peroxide at 45°C Perform pre-cleaning for 2 minutes. After the pre-cleaning is completed, put it into the water tank for 2 minutes, then put the silicon wafer into the alkali polishing tank for polishing for 4 minutes, and then put it into the water tank for 2 minutes of cleaning after polishing, and the alkali polishing etching process is completed.

Embodiment 2

[0047] Take 2.5L alkali throwing tank, add 2L water, raise the temperature to 65°C, then add 100mL of 48% NaOH, and add 30ml of the additive of the present invention after the temperature stabilizes (the formula is: 0.05wt% vanillin, 1wt% % polyphosphate, 3wt% disodium tetraacetate, 0.08wt% benzotriazole, and the balance is deionized water) to prepare a polishing liquid; place the polishing liquid for use after three months, and use the polishing liquid Stir evenly, remove the PSG silicon wafer, and pre-clean in a tank of NaOH and hydrogen peroxide at 45 °C for 2 minutes. Then put it into a water tank for cleaning for 2 minutes, and the alkali polishing etching process is completed.

Embodiment 3

[0052] Get 150L of alkali throw tank, add 140L of water, the temperature is raised to 65 ℃, then add 6L of 48% NaOH, add 3.5L of the additive of the present invention after the temperature stabilizes (formulation is: 0.05wt% vanillin, 1wt% % polyphosphate, 3wt% disodium tetraacetate, 0.08wt% benzotriazole, and the balance is deionized water); after stirring evenly, 1200 pieces of silicon wafers without PSG were polished, and NaOH and Pre-clean in the hydrogen peroxide tank for 2 minutes. After the pre-cleaning is completed, put it in the water tank for 2 minutes, then put the silicon wafer in the alkali polishing tank for polishing for 4 minutes, and then put it in the water tank for 2 minutes after polishing. The alkali polishing etching process is completed; then Enter the subsequent solar cell preparation process to produce finished solar cells.

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PUM

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Abstract

The invention discloses an additive for alkali polishing of a monocrystalline silicon wafer. The additive comprises the following components in percentage by mass: 0.01-1% of a polishing component, 1-3% of a dispersing agent, 1-5% of an anti-settling agent, 0.05-0.1% of a protection agent and the balance of deionized water. According to the invention, the additive is added into the polishing solution for alkali polishing of the monocrystalline silicon wafer, so that the back polished surface of the silicon wafer has high flatness, low specific surface area, no trace, mirror surface effect in appearance and high reflectivity, the final battery efficiency is improved by 0.03-0.05%, and the polishing requirement of a PERC battery is met.

Description

technical field [0001] The invention relates to the field of photovoltaics, in particular to an additive for single crystal silicon wafer alkali polishing and its application. Background technique [0002] At present, the etching and polishing process of solar cells is a crucial step in the manufacturing process of high-efficiency solar cells. It has a significant impact on the electrical properties of finished cells and the EL yield rate. The uniformity of the reflectivity of the silicon wafer after etching determines the The uniformity of the back passivation coating, the uniformity of the coating determines the uniformity of the laser opening rate and size; therefore, etching plays a key role in the production process of PERC cells (Passivated emitter rear contact solar cells) pivotal role. [0003] Alkali polishing is a relatively common technical means at present, but there are often the following problems in alkali polishing: 1) Pyramids will remain if the alkali poli...

Claims

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Application Information

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IPC IPC(8): C30B33/10C30B29/06C09G1/04
CPCC30B33/10C30B29/06C09G1/04Y02P70/50
Inventor 杨勇章圆圆陈培良
Owner CHANGZHOU SHICHUANG ENERGY CO LTD
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