Patent ID: 6927167

Claim:
A method for manufacturing a semiconductor device with a substrate having a device layer disposed on one side of the substrate and a backside electrode disposed on the other side of the substrate, wherein a surface roughness of the substrate, i.e., RS, is defined as a ratio between a substantial area, i.e., SE, and a projected area, i.e., SP, so that the surface roughness is obtained as RS=SE/SP, the substantial area is an area, which is provided by spreading out a concavity and convexity of a surface of the substrate into a predetermined plane, and the projected area is an area, which is provided by projecting the concavity and convexity of the surface to the predetermined plane, the method comprising the steps of: polishing the other side of the substrate mechanically with using predetermined abrasive grains so that a silicon layer thickness of the substrate becomes a predetermined thickness; wet-etching the other side of the substrate after the step of polishing the other side of the substrate so that a surface roughness of the other side of the substrate becomes to be equal to or larger than 1.04; and forming the backside electrode on the other side of the substrate after the step of wet-etching the other side of the substrate.