NOVELTY - A silicon nitride film on the surface of a silicon wafer after abnormal coating removing method involves removing hydrofluoric acid film. Mixed acid treatment is performed by adding 90 l pure water resistivity of 18 megohms into wet-etching machine acid treatment tank, adding 30 l 49% concentration of electronic-grade hydrofluoric and 175 l acid concentration of 70% of the electronic grade nitric acid, in the transmission speed of 0.55m / min, at a temperature of 4 degrees C under the polysilicon sheet membrane for treatment, placing one by one onto the wheel.    USE - Method for removing silicon nitride film on the surface of a silicon wafer after abnormal coating for a crystalline silicon solar cell.    ADVANTAGE - The method enables removing silicon nitride film on the surface of the treated silicon wafer, without residues on the surface of the silicon wafer and with quite small damages on the textured surface of the silicon wafer, so that texturing for the silicon wafer, and ensuring the smooth performance of a production process.    DETAILED DESCRIPTION - A silicon nitride film on the surface of a silicon wafer after abnormal coating removing method involves removing hydrofluoric acid film by adding 130 l pure 18 megohms water into acid treatment tank, adding 24 l 49% electronic grade hydrofluoric acid, at room temperature anomaly to be treated coated sheet immersed in the solution tank for 15 minutes, rinsing tank after the end of the reaction, after drying After get processed polysilicon film stand. Mixed acid treatment is performed by adding 90 l pure water resistivity of 18 megohms into wet-etching machine acid treatment tank, adding 30 l 49% concentration of electronic-grade hydrofluoric and 175 l acid concentration of 70% of the electronic grade nitric acid, in the transmission speed of 0.55m / min, at a temperature of 4 degrees C under the polysilicon sheet membrane for treatment, placing one by one onto the wheel, under the surface contact with each other with the mixed acid liquid, for treating membrane for 4 minutes.