Technology for reducing etching lines on diffuse surface

Abstract

The invention discloses a technology for reducing etching lines on a diffuse surface. The technology comprises the following steps: S1, coating a solid border film: coating a solid border film with the width of 1 to 2 mm and the height of 0.5 to 1 mm along the edge of the diffuse surface of a silicon wafer to be etched; S2, adding water to form a water film: adding water into the inner cavity of the solid border film obtained in S1 so as to form the water film with certain height; S3, etching: putting the silicon wafer to be etched after the water film is formed in S2 into conventional etching equipment for etching; and S4, removing a film layer: carrying out removal of the water film and the solid border film on the silicon wafer after etching is competed in S3. The solid border film and the water film are used cooperatively, the effects of few used materials and short coating time are realized, and the rupture of the water film cannot be caused, so that the corrosion of an etching solution on the diffuse surface is effectively isolated, the area of the etching lines on the diffuse surface is obviously reduced, the generation of poor etching lines on the diffuse surface is reduced, and poor isolation in etching working procedures is also reduced.

Description

technical field [0001] The invention relates to the technical field of silicon chip etching, in particular to a process for reducing etching lines on a diffusion surface. Background technique [0002] Polycrystalline silicon is commonly used to remove the back junction and side junction by wet etching. The commonly used wet etching principle is: the silicon wafer floats on the surface of the etching solution, and the etching solution touches the back surface and edge to remove the N-type silicon. Due to the liquid tension entering the edge diffusion surface, it will inevitably affect the emitter of the diffusion surface, resulting in over-etching. Condensation and etching liquid above the body is low, the exhaust is unstable, and the flow rate is abnormal, etc., causing the diffusion surface to be damaged by the etching liquid, which eventually leads to various poor appearance and electrical failure of the solar cell. [0003] In the prior art, in order to prevent the diffu...

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Problems solved by technology

[0004] However, there are obvious defects in the above two methods: 1. Although the water film method is simple to operate and can also dilute the etching solution to protect the diffusion surface, shaking is likely to occur during the etching process, causing the water film layer to break. Therefore, in the etching process, the diffusion surface cannot be protected stably; 2. Although the solid-state film method can protect the diffusion surface very well and stably, the area of ​​the ordinary silicon wafer is relatively large, and a whole layer is coated on the diffusion surface. Solid film, not only a waste of solid film material, but also a waste of time, very inconvenient

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