PERC solar cell manufacturing method capable of reducing winding plating and chromatic aberration

Abstract

The invention discloses a PERC solar cell manufacturing method capable of reducing winding plating and chromatic aberration. The method comprises the steps of texturing, diffusion, front laser, etching, annealing, back passivation film deposition, front antireflection film deposition, back laser, silk-screen printing and sintering. In the step of the back passivation film deposition, a back surface aluminum oxide film, a back surface silicon oxide film and a first layer of back surface silicon nitride film are sequentially deposited on a back surface of a silicon wafer; and a step of depositing a second layer of silicon nitride film on the back surface is added after the step of front antireflection film deposition and before the step of back laser, and in the step of depositing the secondlayer of silicon nitride film on the back surface, a second layer of back surface silicon nitride film with low refractive index and large film thickness is deposited on the back of a silicon wafer.The cell piece manufactured by the method has the advantages that the front surface appearance color is dark and slightly black, the edge winding plating is less, the front surface film color is uniform and free of color difference, and the strict requirement of a black back plate assembly for the front surface appearance film color of the cell piece can be met.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for manufacturing a PERC solar cell that reduces plating and chromatic aberration. Background technique [0002] Monocrystalline PERC solar cells are one of the most popular high-efficiency solar cells currently on the market due to their simple process and low cost. At present, the manufacturing process of monocrystalline PERC cells mainly includes: texturing—diffusion—SE front laser—etching and polishing—annealing—depositing passivation film on the back—depositing anti-reflection film on the front—laser opening— Back electrode printing - back electric field printing - positive electrode printing - sintering. [0003] The two steps of depositing a passivation film on the back of a solar cell and depositing an anti-reflection film on the surface are currently mainly using the PECVD method to deposit the silicon nitride film on the front and back. The tubular PECVD m...

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Problems solved by technology

[0003] The two steps of depositing a passivation film on the back of a solar cell and depositing an anti-reflection film on the surface are currently mainly using the PECVD method to deposit the silicon nitride film on the front and back. The tubular PECVD method requires the use of a graphite boat as a carrier for the film coating. The silicon chip is limited in the graphite cavity, and only one side of the silicon chip is allowed to be exposed to the process atmosphere of the graphite cavity. The size of the gap will be greater than the thickness of the silicon wafer; during the coating process, the silicon wafer will expand due to heat, and cannot fully maintain the state of bonding with the graphite wall, and the reaction gas will follow the gap between the silicon wafer and the graphite wall caused by thermal expansion. The gap deposits the target film layer on the other side of the silicon wafer. These additional deposited film layers are mainly distributed on the edge of the opposite side of the target deposition surface, resulting in a thicker edge when the film is coated on the other side of the silicon wafer in the next process. Appearance shows that the film color at the edge of the cell is yellowish or white compared with that at the middle position, this phenomenon is called wrap-around plating; a slight wrap-around phenomenon will also occur when using plate PECVD coating

[0004] When the silicon nitride film on the front and back of the solar cell is deposited by the PECVD method, due to the difference in the resistivity of the silicon wafer, the coating temperature and the saturation state of the graphite boat, the coating will be uneven, and the area with low resistivity and high coating temperature The deposition rate is fast. If the graphite boat is fully saturated, there will be no deposition competition at the contact position between the graphite boat and the silicon wafer, which will affect the uniformity of the coating

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