Method for improving contact resistance of silicide layer in a semiconductor device

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

• forming a gate electrode on a semiconductor substrate, wherein said gate electrode includes a silicide film at the uppermost portion thereof;
• forming a source/drain region on the semiconductor substrate;
• forming an interlayer insulating film over the entire surface of semiconductor structure including said gate electrode and said source/drain region;
• selectively etching said interlayer insulating film to form contact holes that expose the surface of the silicide film of the gate electrode and the source/drain region, wherein the selectively etching for forming the contact holes also makes an undesirable side effective film on the silicide film;
• and
• performing a plasma treatment using a gas that does not include any carbon element, in order to remove the side effective film on the silicide film.