A low scratch back contact cell and method of making the same

By combining tank cleaning and RCA cleaning and rewashing, the problems of scratches and contamination on the silicon wafers of back-contact batteries were solved, and the fill factor and efficiency of the batteries were improved.

CN121398224BActive Publication Date: 2026-04-14GOLD STONE (FUJIAN) ENERGY CO LTD
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Patent Information

Application Number
CN202511955601.2
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2025-12-23
Publication Date
2026-04-14
Estimated Expiration
2045-12-23

AI Technical Summary

Technical Problem

In the existing post-texturing process for back-contact batteries, the silicon wafer surface is easily scratched or contaminated by mechanical rollers, affecting the fill factor and battery efficiency.

Method used

A tank cleaning method is used instead of a chain cleaning method. A sacrificial layer is formed on the back of the silicon wafer and etched in an acidic solution to protect the anti-reflective layer on the front side from corrosion. At the same time, the back-side coating is removed. Combined with RCA cleaning and rewashing, the wafer is thoroughly cleaned, avoiding mechanical damage to the back of the silicon wafer.

Benefits of technology

It improved the overall passivation level, reduced scratches on the back of the silicon wafer, and improved the fill factor and cell efficiency.

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Abstract

The application belongs to the technical field of back contact cells, and particularly relates to a low-scratch back contact cell and a preparation method thereof, which comprises the following steps: S2, sequentially forming a first semiconductor layer and a mask layer on the back surface of a silicon wafer; S3, performing etching opening on the back surface to form a second semiconductor opening area; S4, performing texturing and cleaning; S5, sequentially forming a third semiconductor layer and a sacrifice layer on the front surface of the silicon wafer; S6, performing groove cleaning on the back surface and the second semiconductor opening area obtained in S5, wherein the groove cleaning comprises acid solution cleaning, RCA cleaning and backwashing, and the sacrifice layer is removed in the RCA cleaning and backwashing; and S7, depositing a second semiconductor layer on the back surface. The groove cleaning method is used to replace the chain cleaning method, the back surface plating layer can be fully removed, the front surface anti-reflection layer is protected from corrosion, the anti-reflection effect of the front surface is not affected, mechanical damage or pollution of the back surface of the silicon wafer can be avoided, the overall passivation level can be improved, the back surface scratch can be reduced, and the fill factor and the cell efficiency can be improved.
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