Abstract: Cutting work is performed on an n-semiconductor substrate (1) with an inverted trapezoid-shaped dicing blade to form grooves to be a second side walls (7). Bottom portions of the grooves are contacted with a p-diffusion layer (4) which is formed on a first principal plane (2) (front face) of the n-semiconductor substrate (1), so that the p-diffusion layer (4) is not cut. Then in the second side walls (7), a p-isolation layer (9) connected to a p-collector layer (8) and the p-diffusion layer (4) is formed. Since the p-diffusion layer (4) is not cut, a glass support substrate for supporting a wafer, and expensive adhesive, are not required, and therefore the p-isolation layer (4) can be formed at low cost.

Abstract: Cutting work is performed on an n-semiconductor substrate (1) with an inverted trapezoid-shaped dicing blade to form grooves to be a second side walls (7). Bottom portions of the grooves are contacted with a p-diffusion layer (4) which is formed on a first principal plane (2) (front face) of the n-semiconductor substrate (1), so that the p-diffusion layer (4) is not cut. Then in the second side walls (7), a p-isolation layer (9) connected to a p-collector layer (8) and the p-diffusion layer (4) is formed. Since the p-diffusion layer (4) is not cut, a glass support substrate for supporting a wafer, and expensive adhesive, are not required, and therefore the p-isolation layer (4) can be formed at low cost.

Abstract: A method of coating a metal article by forming a first electrodeposition coating layer having varistor properties on a metal article by an electrodeposition coating method by use of an electrodeposition coating film-forming composition containing from 7 to 50 parts by weight of an electrically semiconductive substance per 100 parts by weight of the solid content of the composition, and then forming a second electrodeposition coating layer on said first electrodeposition coating layer by an electrodeposition coating method by use of an anionic or cationic electrodeposition paint while applying a voltage exceeding the varistor voltage. The coating composition thus-produced has excellent varistor properties with superior corrosion resistance.