Patent ID: 9012312
Filing Date: 2015-04-21
Classification: H01L

Abstract:
1. A semiconductor device manufacturing method comprising: (a) forming a first buried diffusion layer of a first conductivity type that contains an impurity of the first conductivity type inside a semiconductor substrate of a second conductivity type; (b) forming a first impurity region by implanting an impurity of the first conductivity type at a first location of a first face of the semiconductor substrate; (c) diffusing the first buried diffusion layer and the first impurity region, by performing a first thermal process on the semiconductor substrate, at least in the thickness direction of the semiconductor substrate to an extent that the first buried diffusion layer and the first impurity region are not connected; (d) forming a second impurity region by implanting an impurity of the first conductivity type at a second location of the first face at a higher concentration than that of step (b); and (e) diffusing the first buried diffusion layer, the first impurity region, and the second impurity region, by performing a second thermal process on the semiconductor substrate, at least in the thickness direction of the semiconductor substrate such that the first buried diffusion layer and the first impurity region are connected to each other, and the first buried diffusion layer and the second impurity region are connected to each other.