Method for forming dense dry etched multi-level metallurgy with non-overlapped vias

Claim 1

A process for forming on a substrate a double level metal interconnection having an etch-stop on the conductor line on a first level metal to prevent overetching thereof when forming a second level metal line in a via hole thereover, comprising the steps of: depositing a first level metal layer on said substrate; depositing a layer of refractory metal on the surface of said first level metal layer; depositing a pattern layer of photoresist on said layer of refractory metal to mask the longitudinal shape of said conductor line to be formed in said first level metal layer; etching said layer of refractory metal and said first level metal layer exposed through said pattern layer of photoresist, forming said conductor line in said first level metal layer covered by said etch-stop; forming an insulating layer over said first metal level conductor lines with a via hole through said insulating layer; forming a patterned second level metal layer on said insulating layer and in said via hole with an etching process which has a reduced etch rate for said refractory metal; whereby said refractory layer forms an etch-stop on said first metal level conductor line for said etching process.