SEMICONDUCTOR DEVICE MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a technology of achieving easy control of impurity concentrations of an N well and a P well while decreasing a level difference of a boundary between the N well and the P well.SOLUTION: A manufacturing method of a semiconductor device having a twin well structure comprises: a first implantation process of performing ion implantation of a first conductivity type impurity into a semiconductor substrate in a first region and a second region which are adjacent to each other; a resist pattern formation process of forming a first resist pattern for covering the first region of the semiconductor substrate and exposing the second region of the semiconductor substrate; a second implantation process of performing ion implantation of a second conductivity type impurity of a concentration higher than that of the first conductivity type impurity to the second region of the semiconductor substrate by using the first resist pattern as a mask; and a diffusion process of thermally diffusing the first conductivity type impurity and the second conductivity type impurity.