A first structure is formed, having a contact plug formed on the bottom of a first opening in an interlayer insulating film, a second opening formed through the interlayer insulating film to reach a semiconductor substrate, and a third opening formed through the interlayer insulating film to reach a polymetal gate electrode. A cobalt layer is deposited on the surface of the structure, and thermally treated to form a cobalt silicide layer on the surface of the contact plug and on the bottom face of the second opening. The structure is then treated to remove the cobalt, in the state in which the cobalt silicide layer is formed, with the use of a chemical solution capable of dissolving cobalt but not the polymetal.