Fabrication process of a semiconductor device having a multilayered interconnection structure

Claim 1

A method of fabricating a semiconductor device, said semiconductor device comprising a substrate and an interconnection structure provided on said substrate, said interconnection structure including an insulation film and a plurality of openings formed in said insulation film such that said openings extend from an upper major surface of said insulation film toward a lower major surface of said insulation film, said method comprising the steps of: (A) overfilling said openings by a conductive material and overetching such that said conductive material fills said openings from a bottom edge of said openings to a level below a top edge of said openings; (B) applying, after said step (A), a sputter-etching process to said insulation film, such that only an upper edge of each of said openings is removed, said contact hole thereby forming a tapered part above said level, such that a diameter of said openings increases continuously and gradually, in said tapered part, toward said upper major surface of said insulation film; (C) depositing, after said step (B), a conductor layer on said insulation film such that said conductor layer fills said tapered part of said openings in contact with said conductive material filling said openings.

Claim 2

A method of fabricating a semiconductor device, said semiconductor device comprising a substrate and an interconnection structure provided on said substrate, said interconnection structure including an insulation film and a plurality of openings formed in said insulation film such that said openings extend from an upper major surface of said insulation film toward a lower major surface of said insulation film, said method comprising the steps of: (A) overfilling said openings by a conductive material and overetching such that said conductive material fills said openings from a bottom edge of said openings to a level below a top edge of said openings; (B) applying, after said step (A), a sputter-etching process to said insulation film, such that only an upper edge of each of said openings is removed, said contact hole thereby forming a tapered part above said level, such that a diameter of said openings increases continuously and gradually, in said tapered part, toward said upper major surface of said insulation film; (C) depositing, after said step (B), a conductor layer on said insulation film such that said conductor layer fills said tapered part of said openings in contact with said conductive material filling said openings.