Abstract: At present, the technology of tunnel oxide passivated contact (TOPCon) solar cells is becoming more and more mature, and the manufacturing cost is decreasing. TOPCon cell technology has been applied in the process of manufacture. Low-pressure chemical vapor deposition (LPCVD) is widely used in the industry for double-sided deposition or single-sided deposition. Single-sided deposition has the problem of Poly-Si winding coating, which seriously affects the efficiency and appearance quality of solar cells. It is difficult to remove the winding coating on the front side. While removing the winding coating in alkali solution, there is a risk of incomplete removal of the winding coating or corrosion risk of P⁺ layer in non-winding plating area. As a result, the P⁺ emitter is damaged, which seriously affects the appearance quality and performance of solar cells. Double-sided deposition can avoid the above risks, but the production capacity will be reduced by half, the manufacturing cost will increase. In this paper, the single-sided deposition of Poly-Si process and the removal process of the winding coating were studied. A layer of oxide coating with appropriate thickness is made on the front and back of TOPCon solar cells. With appropriate cleaning process and unwinding plating cleaning process, the Poly-Si winding coated with P⁺ layer can be effectively removed, and the front P⁺ layer and the doped Poly-Si layer on the back can be well protected from damage, and the production capacity can be greatly improved.

Key words: TOPCon solar cell, Poly-Si winding coating, low pressure chemical vapor deposition, BSG, PSG, corrosion rate