A metal plug is formed in a connection hole such as a via hole or a contact hole to provide an interconnection between multilayer wires in a semiconductor integrated circuit. First, an adhesion layer is deposited on an insulating film, and an area of the adhesion layer is etched away isotropic etching...http://www.google.es/patents/US5374591?utm_source=gb-gplus-sharePatente US5374591 - Method of making a metal plug
