Evaluation of 193-nm immersion resist without topcoat

A production-preferred solution is 193-nm immersion resist without a topcoat. The challenge of 193-nm immersion resist is both low leaching level and high performance. We summarize the screening results of selected 193-nm immersion resists that are designed for use without top coatings. Our evaluation is divided into several phases. Leaching levels of resist samples are first tested. The leaching data are analyzed and compared to our specifications. Both binary intensity mask and alternating phase-shift mask exposures are performed to evaluate the process window, lineedge roughness, and resist pattern profile. Resist films are rinsed by deionized (DI) water prior to or after exposure, and contrast curves are measured to investigate the resist sensitivity change. The results are compared with resist systems that use developer-soluble topcoats. (C) 2006 Society of Photo-Optical Instrumentation Engineers.