Photoresist Systems for Use in 193 nm Microlithography

The extension of optical microlithography to the production of the next generation of semiconductor devices has been enabled by the recent progress on the field of 193 nm lithography utilizing ArF excimer lasers. Among the most important of these developments has been the design of innovative photoresist technologies to overcome the high absorbance at 193 nm of the deep-UV resists currently in use. Two such systems will be discussed. One technology employing plasma polymerized methylsilane (PPMS) as the photosensitive material, is a novel all-dry photolithographic process in which PPMS provides a flexible resist platform that is sensitive at both 248 and 193 nm and can be developed to yield either positive or negative tone images. Another photoresist system, based upon poly(cycloolefin - maleic anhydride) has provided one route to practical 193 nm photolithography and has the ability to define features in silicon that are on the order of 0.1 micron. Performance optimization is achieved by modifying these multicomponent photoresist formulations. The role of additives such as cholate-based dissolution inhibitors and onium salt based photoacid generators will be discussed.