Solar cell silicon wafer polishing method

Abstract

The invention relates to a solar cell silicon wafer polishing method. The method comprises the steps that PSG on the back of a silicon wafer after phosphorus diffusion is removed; the silicon wafer is immersed in a tetramethylammonium hydroxide polishing agent; and polishing is carried out on the back of the silicon wafer. The method provided by the invention has the advantages that the weight loss of the polished silicon wafer is reduced through single side polishing; without affecting the sheet resistance of the diffused silicon wafer and a front PN junction, a polishing technology process is simplified; the back of the silicon wafer is smooth through polishing; the reflectivity is between 50% and 60%; and a back passivation technology is combined, thus the overall efficiency of a cell is improve by 0.15% to 0.25%.

Description

technical field [0001] The invention relates to a polishing method for a silicon wafer of a solar battery. Background technique [0002] In the prior art, the method of alkali polishing silicon wafers is: double-sided polishing of bare silicon wafers with alkali polishing liquid. The disadvantage of this polishing method is that the weight loss of silicon wafers after polishing is large, and the broken pieces and defective parts in subsequent production More losses. In order to achieve single-sided polishing and ensure that the textured surface of the silicon wafer is not affected during polishing, it is necessary to grow a silicon nitride or silicon dioxide protective layer on the textured surface first, and then put the silicon wafer in the lye bath for polishing , and this process is generally performed before diffusion. If polishing is performed after diffusion, it is easy to affect the diffusion resistance of the silicon wafer and the PN junction generated by diffusion...

AI Technical Summary

Problems solved by technology

[0002] In the prior art, the method for alkali polishing of silicon wafers is: double-sided polishing of bare silicon wafers with alkali polishing solution. The disadvantage of this polishing method is that the weight loss of silicon wafers after polishing is large, and the broken pieces and defective pieces in subsequent production more losses

In order to achieve single-sided polishing and ensure that the textured surface of the silicon wafer is not affected during polishing, it is necessary to grow a silicon nitride or silicon dioxide protective layer on the textured surface first, and then put the silicon wafer in the lye bath for polishing , and this process is generally performed before diffusion. If polishing is performed after diffusion, it is easy to affect the diffusion resistance of the silicon wafer and the PN junction generated by diffusion during the process of removing the silicon nitride or silicon dioxide protective layer.