A two-stage electrophoresis process

Abstract

A two-stage electrophoresis process comprises the steps of S1, electrophoresing a silicon wafer with a low concentration electrophoresis liquid; S2, adding a nominal amount of glass powder and an additive liquid to the used electrophoresis liquid; S3, placing the silicon wafer after the S1 in the electrophoresis liquid of the S2 for electrophoresis. Compared with the original process, the two-stage electrophoresis process has the advantages that the electrophoresis process is more stable, the shape of the glass in a tank is more uniform and more symmetrical, the stability of the electrical properties of the product is enhanced, the defect rate of the product is lowered, and the reuse of the electrophoresis liquid is achieved. The utilization rate of glass powder is improved to reduce the cost of electrophoresis.

Description

technical field [0001] The application belongs to the technical field of silicon wafer wet etching, and in particular relates to a two-stage electrophoresis process. Background technique [0002] GPP is the abbreviation of Glassivation passivation parts, which is a general term for glass passivation devices. This product is to burn a layer of glass around the P / N junction surface of the tube core to be divided on the basis of the existing ordinary silicon rectifier diffusion sheet. The glass and single crystal silicon have good bonding characteristics, so that the P / N junction Get the best protection from the intrusion of the external environment, improve the stability of the device, and have excellent reliability. [0003] The currently used method of coating a glass passivation layer on the surface of single crystal silicon is electrophoresis. Usually, if the required thickness of the glass layer is reached, the electrophoretic solution needs a certain concentration, and ...

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Problems solved by technology

[0003] The currently used method of coating a glass passivation layer on the surface of single crystal silicon is electrophoresis. Usually, if the required thickness of the glass layer is reached, the electrophoretic solution needs a certain concentration, and the electrophoretic solution with a high concentration of glass powder is often electrophoresis. There are many defects, such as unstable electrophoresis process, asymmetric shape of the glass in the tank, and even batches of products with defective glass in the tank, which lead to hidden dangers in the quality of GPP

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