Crystalline silicon solar battery edge etching process

Abstract

The invention belongs to the field of a solar battery manufacture process, in particular to a crystalline silicon solar battery edge etching process, which comprises the steps of edge etching and residue removal. The invention adopts a corrosive chemical pulp spray coating method for etching the edge of a silicon chip, the etching amount of the periphery of the silicon chip surface can be controlled within 0.2 mm, the PN junction loss of the silicon chip surface can be greatly lowered, the light absorption of the light absorption surface of the silicon chip can be improved, the photoelectric efficiency of batteries can be improved, the process is stable, and the control is easy.

Description

Technical field [0001] The invention belongs to the field of solar cell manufacturing processes, and in particular relates to a crystalline silicon solar cell edge etching process. Background technique [0002] During the diffusion process of solar cells, whether it is single-sided diffusion or double-sided diffusion, a diffusion layer is inevitably formed on the periphery of the silicon wafer. The peripheral diffusion layer makes the upper and lower electrodes of the battery form a short-circuit ring, which must be removed to separate the PN junction between the front and back of the battery. Any small local short circuit on the periphery will reduce the parallel resistance of the battery, increase the reverse current, and reduce the overall electrical performance of the solar cell. [0003] At present, the edge removal processes used in industrial production mainly include dry plasma etching process, wet chemical etching method and laser edge etching method. The plasma dry etch...

AI Technical Summary

Problems solved by technology

The plasma dry etching process is to etch the periphery of the silicon wafer through the alternating action of fluorine and oxygen under the condition of glow discharge. The equipment cost of this process method is relatively low, but the etching amount Larger, usually the front surface is etched at about 1-2mm, and the photocurrent loss is relatively large

The wet chemical etching method uses an etching solution composed of nitric acid and hydrofluoric acid to etch the edge of the silicon wafer. It also has the problem of a large amount of front etching, and the equipment cost is relatively high.

Another method is to use the laser method to etch the edge of the battery to achieve the purpose of separating the front and back PN junctions. This method has less etching on the front and good process stability. However, due to the thermal damage of the laser to the silicon wafer, the battery The performance is reduced, so it is less used in industrial production