Patent ID: 6962771

Claim:
A method of photoresist processing comprising: providing a substrate over which is formed composite layers of insulation comprising a first layer of dielectric separated from a second layer of dielectric by an intermediate etch stop layer of dielectric; forming a top dielectric layer over said composite layers of dielectric; forming a first photoresist layer over said composite layers of insulation and top insulating layer; patterning a via hole pattern in said first photoresist layer by exposing to I-line 365 nm radiation and developing; forming a second photoresist layer over via patterned said first photoresist layer; patterning a trench line pattern in second photoresist layer by exposing to deep-UV 248 nm radiation and developing; etching top and second layer of dielectric underlying first layer of photoresist using the via hole pattern layer; etching said intermediate layer of dielectric under said second layer of dielectric using the first layer of photoresist as a mask; etching said composite layer of insulation transferring said trench line pattern into said first layer of photoresist and into said second layer of dielectric and transferring said via hole pattern into said intermediate layer of dielectric and into said first layer of dielectric; removing said layers of photoresist and filling the trench line and via hole openings with metal.