A silicon film is deposited using low pressure chemical vapor deposition (LPCVD) to fill in openings formed in a substrate such as an insulating film. An aluminum film and a metal film are then formed on the silicon film. A thermal process is then carried out. This thermal process causes the deposited aluminum to replace the silicon in the openings because the silicon migrates to the metal and forms a metal silicide film. The aluminum which replaces the silicon in the openings has few or no voids. The metal silicide film any remaining portion of the aluminum film are then removed using CMP, for example.