REVERSE BLOCK SEMICONDUCTOR DEVICE MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a reverse block semiconductor manufacturing method which sufficiently retains a function of a mask oxide film and which is unlikely to cause unwanted boron doping to a region other than an isolation region though a thickness of the mask oxide film is thinned.SOLUTION: A reverse block semiconductor device manufacturing method comprises a process of performing ion implantation of boron by using an oxide film 15b of a thickness of 0.8 μm and under as a mask and forming a p-type isolation region 31a by thermal drive diffusion after removing a boron glass 15c.