CHEMICAL AMPLIFICATION MECHANISMS FOR MICROLITHOGRAPHY

Continued advances in microelectronic device fabrication are trying the limits of conventional lithographic techniques. In particular, conventional photoresist materials are not appropriate for use with the new technologies that will be necessary for sub-0.5-mu-m lithography. One approach to the design of new resist chemistries involves the concept of chemical amplification, where one photochemical event can lead to a cascade of subsequent reactions that allow patterning of the parent material. Generally, chemically amplified resists utilize photochemically generated acid to catalyze cross-linking or deprotection reactions. This paper reviews the chemistries that have been evaluated for chemical amplification resist processes; acid generator, cross-linking, deprotection, and depolymerization chemistry.