Method for manufacturing semiconductor chip and protective film forming agent which can form a processing groove on the semiconductor wafer and the protective film by irradiating a laser beam with high processing accuracy

The subject of the present invention is to provide a method for manufacturing a semiconductor chip and a protective film forming agent that can be used in the manufacturing method of the semiconductor wafer. The manufacturing method of the semiconductor wafer is a manufacturing method of the semiconductor wafer by cutting off the semiconductor wafer, which can form a processing groove on the semiconductor wafer and the protective film formed on the semiconductor wafer by irradiating a laser beam with high processing accuracy. The solution is a method for manufacturing a semiconductor wafer by cutting off the semiconductor wafer (2), including: coating a protective film forming agent containing a water-soluble resin (A), a light absorbent (B) and a solvent (S) on the semiconductor wafer (2) to form a protective film (24); and irradiating laser beam with a wavelength of 515 nm at a fixed position on the semiconductor wafer (2) containing the protective film (24) of more than one layer, so that the surface of th