Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising the steps of:

• forming an impurity diffusion region in a semiconductor layer;
• forming an insulating film having a thickness of 0.5 pm or greater on said semiconductor layer;
• forming an etching mask on said insulating film;
• and
• forming, in said insulating film, an opening that reaches an upper surface of said semiconductor layer and has a dimension of 2 mm x 2 mm or greater in a plan view, through etching by the use of said etching mask as a mask to expose at least part of said impurity diffusion region from said insulating film,
• wherein said step of forming said opening comprises the steps of
• removing said insulating film so as to leave one-half or less of a thickness of said insulating film unremoved, through dry etching by the use of said etching mask as a mask, and
• removing said insulating film until said opening reaches said upper surface of said semiconductor layer, through wet etching by the use of said etching mask as a mask.