Manufacturing method for power device

The invention discloses a manufacturing method for a power device. The manufacturing method comprises the following steps: firstly, completing a front surface process on the front surface of a silicon wafer, including coating polyimide; secondly, thinning the back surface of the silicon wafer, and performing back surface ion implantation and annealing activation; 3a, processing the back surface of the silicon wafer by adopting a wet spinning etching process; 3b, washing the silicon wafer by using deionized water with mega sonic waves; 3c, drying the back surface of the silicon wafer by a nitrogen blowing method and a high-speed spin-drying method; fourthly, forming metal on the back surface. By the manufacturing method for the power device, the pollution of the polyimide to the back surface of the silicon wafer can be eliminated, the metal on the back surface can be prevented from peeling, and the manufacturing method can be applicable to the requirement on large-scale production.