METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE WHICH A PLURALITY OF TYPES OF TRANSISTORS ARE MOUNTED

摘要

A method of manufacturing a semiconductor device includes the steps of forming a trench on a semiconductor substrate to define a first and a second element regions; burying a first oxide film in the trench; forming a second oxide film on surfaces of the first and second element regions; performing a first ion doping using a first mask which is exposing a first region containing the first element region and a part of the first oxide; performing a second ion doping using a second mask which is exposing a second region containing the second element region and a part of the first oxide film; and removing the second oxide film formed in the first element region and the second element region by etching, and the first oxide film is selectively thinned using the first or second mask after performing the first or second ion doping.