Basic etching back-polishing process for crystalline silicon battery

Abstract

The invention discloses a basic etching back-polishing process for crystalline silicon batteries. The basic etching back-polishing process includes spraying water on the front side of a silicon chip to protect the front side PSG layer of the silicon chip, removing PSG layer on the back side of the silicon chip with HF solution, washing in a water tank, drying the surface the silicon chip through blowing, transmitting the silicon chip into an immersion type alkali groove to corrode the back side of the silicon chip with weak base, washing in a water tank, removing the PSG layer on the front side of the silicon chip with HF solution, washing in a water tank, and drying by blowing. The basic etching back-polishing process ensures efficiency and stability of batteries, no etching stamps may be formed to affect the appearance of the battery, and p-n junctions may not be damaged. Acid consumption may be lowered, the back polishing effect is excellent, and no acid corrosion is on the front side. Weak photoelectric effect is facilitated, the electric leakage proportion is low, and sheet resistance may not be increased.

Description

technical field [0001] The invention relates to the field of crystalline silicon solar cells, in particular to an alkaline etching back-throwing process for crystalline silicon cells. Background technique [0002] With the release of solar profit margins for crystalline silicon cells, the competition is getting bigger and bigger. How to reduce costs and improve the yield has become one of the important issues for every enterprise. The edge engraving process is one of the most important joints of crystalline silicon cells. Various edge engraving methods are currently popular in the market, but all have their shortcomings. [0003] Mainstream etching process: [0004] 1) Rena type: The method of "floating on water" is adopted. Since the PSG layer on the surface of the silicon wafer after diffusion is hydrophilic, the acid will climb to the surface of the silicon wafer when the mixed acid is edged, and it is easy to form an "etching mark" and affect the appearance of the batte...

AI Technical Summary

Problems solved by technology

The final result is that this kind of process wastes a lot of acid liquid; see the process flow figure 2 shown

[0006] 3) Kutler type: first remove the PSG layer on the entire surface of the silicon wafer by spraying, and then edge-cutting, this process will cause the p-n junction to be exposed to acid mist during edge-cutting, thereby destroying the p-n, resulting in an increase in square resistance

The parallel resistance of batteries made by this process is generally an order of magnitude lower than that of wet etching, which is not conducive to weak light effects, and the leakage ratio is relatively high

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