Advanced Groundrule Processing Performed With Currently Available Photolithographic Tools
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Early implementation of advanced groundrules to produce small geometry metal pitches is practical using presently available photolithographic tools. The technique utilizes image-reducing properties of the sidewall image transfer process, double masking on a single level and a metal hole fill process. Metal patterns smaller than those being produced using current optical lithography are made by combining sidewall image transfer techniques with two sequential offset masking steps. Patterns are produced with a density improvement of as much as a factor of two over current processing methods. Fig. 1 shows photoresist applied and patterned on top of the first level metal oxide insulator. Sidewall spacers are formed on the sides of the resist stack by chemical vapor deposition (CVD) of an insulator material over the entire structure.