Patent ID: 8697558
Filing Date: 2014-04-15
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device, the method comprising the steps of: forming a trench having a substantially V-shaped or trapezoidal-shape cross section, in a second principal surface of a first conductivity type semiconductor substrate having a first principal surface and the second principal surface; introducing a second conductivity type impurity into a side wall of the trench; and activating the impurity by laser irradiation, wherein the side wall of the trench is formed so as to have an angle of inclination of over 30° and under 70° relative to the first principal surface, wherein the laser irradiation is carried out with a laser beam made incident to the side wall of the trench, with the laser beam being incident to the second principal surface of the semiconductor substrate at an angle of incidence of ±30° off a normal to the second principal surface, and wherein the laser irradiation is carried out with a focus point of the laser beam being incident to the side wall of the trench so that no molten crystal mark or work mark appears on the second principal surface of the semiconductor substrate.