Manufacturing method of semiconductor device

Abstract

Provided is a semiconductor device with improved performance and production yield. Insulating films ILand ILare formed over a semiconductor substrate in that order to cover a gate electrode. Then, the insulating films ILand ILare etched back to form sidewall spacers including the insulating films ILand ILover sidewalls of the gate electrode. The source/drain region is formed in the semiconductor substrate by ion implantation using the gate electrode and the sidewall spacer as a mask. Then, the sidewall spacers are isotropically etched on conditions where the insulating film ILis less likely to be etched than the third insulating film ILto thereby decrease the thickness of the sidewall spacer. Thereafter, a reaction layer between the metal and the source/drain region is formed over the source/drain region.