Method of fabricating a semiconductor device having miniaturized contact electrode and wiring structure

A method of fabricating a semiconductor having a miniaturized contact electrode and wiring structure, comprising the steps of:

• forming a first interlayer insulating film on a semiconductor substrate;
• forming a first buffer layer on said first interlayer insulating film and a stopper insulating film on said first buffer layer;
• selectively forming a first opening having a bottom inside said first interlayer insulating film and shallower than a thickness of said first interlayer insulating film;
• forming a second buffer layer to cover said first opening and said stopper insulating film;
• performing anisotropic etching to leave said second buffer layer on a sidewall of said first opening;
• executing anisotropic etching with said first and second buffer layers used as masks to penetrate that part of said bottom of said first opening which is exposed, and forming a second opening to expose a face of said semiconductor substrate;
• filling a first wiring conductor in said second opening and said first opening following said second opening;
• forming a contact electrode on said first wiring conductor filled in said first opening as wide as a width of said first opening, and selectively forming a first wiring layer on said first interlayer insulating film;
• depositing a third buffer layer and performing anisotropic etching to leave said third buffer layer on sidewalls of said contact electrode and said first wiring layer;
• forming a second interlayer insulating film to cover said contact electrode and said first wiring layer, and forming a third opening in said second interlayer insulating film so as to expose said first wiring layer;
• forming a second wiring conductor on said first wiring layer so as to fill an interior of said third opening;
• and
• forming a second wiring layer on said second wiring conductor.