Etching process of solar energy cell chips capable of reducing NOx emissions

Abstract

The invention relates to the technical field of cell chip etching, in particular to an etching process of solar energy cell chips capable of reducing NOx emissions. The etching process comprises the following steps of (1), evenly attaching deionized water to the upper surface of a to-be-etched silicon chip to form water film; (2), adjusting the flatness of rollers in an etching tank so as to enable all the rollers to remain absolutely horizontal; (3), adding optimization etching liquid into the etching tank; (4), putting the to-be-etched silicon chip into the etching tank for etching. By forming a layer of the deionized water film on the upper surface of the silicon chip, the etching process can greatly weaken the negative effects on the appearance and efficiency of the silicon chip; after the acid etching liquid can not diffuse to the upper surface of the silicon chip, waste of the etching liquid is reduced, so is the dosage of nitric acid; therefore, the emissions of NOx are reduced, and the effects of environment protection and NOx treatment cost reduction are achieved on the premise that the efficiency of etching silicon chips and etching effects are guaranteed.

Description

technical field [0001] The invention relates to the technical field of cell etching, in particular to a solar cell etching process capable of reducing NOx emissions. Background technique [0002] The cell diffusion process adopts the back-to-back single-sided diffusion technology of two cells. After diffusion, phosphorus atoms will be diffused on the upper surface and edge of the silicon wafer to form a PN junction, which can form a photovoltaic effect under the action of light. However, the electrons generated by it will be conducted to the lower surface of the cell along the edge PN junction, causing a short circuit of the cell. Therefore, another important process in the production of solar cells - etching, its main purpose is to remove the PN junction at the edge of the cell to avoid leakage failure of the cell. [0003] The principle of the wet etching process is that the silicon wafer is supported and conducted by rollers, and floats forward on the etching bath. The s...

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Problems solved by technology

[0004] In the prior art, the etching process has the following two obvious defects: 1. Since the surface of the diffused silicon wafer is hydrophilic, the acid solution will be absorbed and diffused to the upper surface of the silicon wafer due to the effect of tension when the edge contacts the acid solution , a circle of etching lines will be formed around the upper surface of the cell, which will have a negative impact on the appearance and efficiency of the silicon wafer;

[0005] 2. In order to achieve a good etching effect and optimize the etching line, the traditional etching formula will increase the proportion of nitric acid, the general volume ratio HF:HNO3=1:5, and the etching nitric acid product NOx pollutes the environment, and the product NOx The treatment cost is high, in order to protect the environment and reduce the company's operating costs, it is necessary to conduct research on reducing the use of nitric acid

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