STRUCTURE AND METHOD OF FORMING TRANSITIONAL CONTACTS BETWEEN WIDE AND THIN BEOL WIRINGS

摘要

A structure and method of forming a conducting via for connecting two back end of the line (BEOL) metal wiring levels is described. The method includes forming a first interconnect structure having a first dimensional width in a first dielectric layer; depositing a second dielectric layer over said first dielectric layer; etching an interconnect trench in the said second dielectric layer; etching a interconnect via using a photo resist mask to form a first portion of the transitional via; reacting the photo resist to expand the photo resist at least in the lateral direction; etching the said dielectric layer using the reacted photo resist to form the second portion of the transitional via; and filling the said interconnect trench and the said interconnect via with metal.