JPS6450545A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To decrease contact resistance at an interlayer connecting section of silicide- polysilicon-metal (silicide)-type interconnections independently from an amount of dopants in the polysilicon and to obtain an ohmic contact, by selectively and thermally oxidising the connecting section between a polysilicide interconnection and an underlying conductor layer. CONSTITUTION:In order to provide a polysilicide interconnection 8 on an underlying conductor layer 5 comprising a layer 5B of a high-melting metal or a silicide thereof, the polysilicide interconnection 8 is formed on an insulating film 6 covering the underlying conductor layer 5 such that the polysilicide layer is in contact with the underlying conductor layer 5 through an aperture 7 formed in the insulating film 6. The contact section between the polysilicide interconnection 8 and the underlying conductor layer 5 is selectively and thermally oxidized so that the polysilicon 8A in the upper layer in the oxidized section of the polycide interconnection 8 is diffused to the surface of the polysilicide interconnection 8 to oxidize the same, whereby the upper silicide layer 8B of the polysilicide interconnection 8 is directly contacted with the underlying conductor layer 5 at said section. According to an embodiment, the surface of the polysilicide interconnection 8 exposed through an aperture 10 in the Si2N4 film 9 is thermally oxidized within moistened oxygen at about 900 deg.C so that Si is diffused.