Method for manufacturing semiconductor device

摘要

A method is provided for manufacturing a semiconductor device having a high breakdown voltage transistor and a low breakdown voltage transistor with different driving voltages provided in a common layer. The method includes: (a) implanting an impurity of a second conductivity type in a specified region of a semiconductor layer of a first conductivity type to form a first well; (b) implanting an impurity of the second conductivity type in a specified region of the semiconductor layer to form a second well having an impurity concentration different from the first well; and (c) implanting an impurity of the first conductivity type in a specified region of the first well to form a third well.