Method of forming an interconnection with metal plug and reduced step

A method of forming an interconnection, comprising the steps of:

• forming an insulating film covering a surface of a substrate having a region to be connected to an interconnection;
• forming an interconnection layer on said insulating film;
• forming an antireflection layer on said interconnection layer;
• forming a connection hole through a laminate of said antireflection layer, said interconnection layer, and said insulating film, by photolithography and selective etching, said connection hole exposing said connection region;
• patterning a laminate of said interconnection layer and said antireflection layer to leave a portion of said laminate on said insulating film at least at a peripheral area around said connection hole, by photolithography and selective etching;
• forming a conductive adhesion layer on said insulating film, said adhesion layer covering said left portion of said laminate and the inner surface of said connection hole;
• and
• forming a conductive layer burying said connection hole and etching back said conductive layer,
• wherein a portion of said conductive layer is left on an outer side wall of said portion of said laminate left on said insulating film at a peripheral area around said connection hole, so as to relieve a step of said left portion of said laminate.