Contactless local interconnect process utilizing self-aligned silicide

Abstract

A contactless, self-aligned local interconnect structure provides a continuous silicide film electrically coupling an upper silicon structure to a lower silicon structure. The upper silicon structure overlaps the lower silicon structure and is insulated from the lower silicon structure by an insulating layer formed between the structures. The continuous silicide film electrically couples the two structures by bridging the gap formed by the insulating layer in the overlap region. The associated process for forming the local interconnect structure includes forming a lateral edge of the upper silicon structure extending over the lower silicon structure, forming a blanket metal film, then heating the metal film such that the metal film reacts with the exposed silicon of the upper silicon structure and the lower silicon structure to form a continuous silicide film which bridges the gap formed by the insulating layer which is formed of a thickness chosen to be suitably low. After the silicide film is formed, unreacted portions of the metal film are removed.