Method for making metal interconnection with chlorine plasma etch

Abstract

A metal interconnection is prepared by forming an underlying metal film of high melting point metal such as Ti and/or high melting point metal compound such as TiN layers above a semiconductor substrate, plasma etching the surface of the underlying metal film in a gas atmosphere containing chloride, and forming an interconnecting metal film such as Al, Cu, Au and Ag on the underlying metal film. Alternatively, a metal interconnection is prepared by forming an insulating film above a semiconductor substrate, forming connection holes in the insulating film, forming an underlying metal film such as TiN on the insulating film and the bottom and side wall of the connection holes by a CVD process under controlled conditions, and forming an interconnecting metal film such as Al on the underlying metal film. The TiN film has (111) preferential orientation and the aluminum film has (111) preferential orientation, smooth surface and effective coverage. The thus fabricated metal interconnection has improved reliability including electromigration immunity when used in semiconductor devices and finding advantageous use in miniaturized semiconductor devices.