Method of creating controlled discontinuity between photoresist and substrate for improving metal lift off

Abstract

A process for forming a photoresist image on a substrate and a process for forming metal contacts on a substrate are described. The process of forming a photoresist image includes depositing a positive working photoresist composition onto a metal layer which is on a substrate to thereby form a photoresist layer then imagewise exposing the photoresist layer to actinic radiation and developing said photoresist layer to form a plurality of cavities through the photoresist layer thereby revealing portions of the metal layer. Then the inventions provides for etching away the revealed portions of the metal layer followed by an overall exposing both the substrate and the remaining photoresist layer and remaining metal layer portions to sufficient electron beam radiation to render a part of the photoresist layer directly adjacent to the metal layer more soluble in a developer than the balance of the photoresist layer. Finally, the more soluble part of the photoresist layer is partially developed to thereby expand the cavities to form notches in the photoresist layer directly adjacent to the metal layer. In order to form the metal contacts of the present invention the invention provides for the further steps of depositing a metal into said cavities and notches to thereby form a conductive attachment to said metal contacts and removing the remaining photoresist and any metal which is not attachment-forming to thereby form metal contacts on the substrate. Microelectronic devices prepared by the same process are also disclosed.