Patent ID: 7537987

Claim:
A semiconductor device manufacturing method, Comprising the steps of: (A) forming a gate insulating film on a semiconductor substrate having an n-FET formation region and a p-FET formation region; (B) forming a metal film which forms a gate electrode on said gate Insulating film; and (C) removing said metal film, while retaining said gate insulating film in said n-FET formation region by a wet etching process using a chemical liquid comprising one selected from the group consisting of a hydrogen peroxied solution, a mixed acid, a hydrogen peroxide and aqueous ammonia, and a hydrogen peroxide solution and mixed acid; further comprising the steps of: (D) after said step (C), forming a polysilicon film over said semiconductor substrate to cover said gate insulating film and said metal film; (E) applying a dry etching process to said polysilicon film to remove part of said polysilicon film, and stopping the dry etching process when the dry etching reaches said metal film; and (F) applying a wet etching process using said given chemical liquid to remove part of said metal film that resides in said p-FET formation region.