Patent ID: 7638395

Claim:
A method for fabricating a semiconductor device having first and second regions, transistors of different conductivity types being formed on parts of a substrate corresponding to the first and second regions, the method comprising the steps of: (a) forming a first insulating film to cover the parts of the substrate corresponding to the first and second regions; (b) forming a first thin film on the first insulating film, the first thin film having a relatively higher etching rate than the first insulating film in plasma etching using a halogen gas; (c) removing a part of the first thin film corresponding to the first region by the plasma etching using a mask covering the second region and modifying a part of the first insulating film corresponding to the first region; (d) after the step (c), forming a first metal film having a first work function to cover the first and second regions; (e) removing a part of the first metal film corresponding to the second region by etching using a mask covering the first region; (f) after the step (e), removing a part of the first thin film corresponding to the second region by the plasma etching using the mask covering the first region and modifying a part of the first insulating film corresponding to the second region; (g) forming a second metal film having a second work function on the part of the first insulating film corresponding to the second region; (h) between the steps (d) and (e), forming a second thin film on the first metal film, the second thin film having a relatively higher etching rate than the first metal film, and (i) removing a part of the second thin film corresponding to the second region by etching using the mask covering the first region.