Semiconductor device having a double-layer interconnection structure

In a semiconductor device of the type which comprises a first metal film formed on a semiconductor substrate, an insulating film having openings and formed on the first metal film, a second metal film provided in electric connection with the first metal film through the openings of the insulating film, and a protective layer made of a film selected from the group consisting of phosphosilicate glass and non-doped silicate glass and a silicon nitride film formed on the second metal film in this order wherein the first and second metal films have, respectively, a multi-layer structure including a first sub-layer made of a member selected from Ti, TiN, TiW, Co and W, a second sub-layer made of a metal selected from Al and Al alloys containing Si, Cu, Ti, Pd or mixtures thereof in an amount of up to 5 wt % in total, and a third sub-layer made of a member selected from the group consisting of Ti, TiN, TiW, Co and W, the improvement characterized in that a value obtained by multiplying a thickness of the silicon nitride film formed on the second metal film layer at the openings by a stress of the silicon nitride film is not larger than 2/5 of a value of a thickness of the silicon nitride film formed on the second metal film on portions other than the openings by a stress of the silicon nitride film on the portions.