Pattern forming and etching process using radiation sensitive negative resist

Claim 1

A pattern forming and etching process for use in microfabrication processes, said pattern and etching process comprising the steps of (A) selectively exposing an article comprising a substrate and an overlying radiation sensitive layer consisting essentially of a polymeric material to radiation to form a pattern in which the ease of removal of the irradiated portions of said overlying layer by a developing agent is decreased; (B) treating said overlying layer with said developing agent to selectively remove the unexposed portions thereof; and (C) dry etching the article with etching gases whereby said article surface corresponding to the removed portions of the patterned overlying layer are preferentially etched; characterized in that said polymeric material consists of a polymer which contains at least 50 percent by monomeric unit ratio of one or a combination of monomeric units selected from the group of: ##STR3## wherein said polymer has a weight average molecular weight M w within the range of 10,000 to 1,000,000 and wherein the polydispersivity of said polymer M w /M n , wherein M n is number average molecular weight, is less than 5.