Short Develop Time Process with Novel Develop Application System

摘要

A short develop time process was investigated and assessed in terms of various pattern features of a resist. Process latitude for a positive DUV resist was evaluated for various pitches of line-and-space patterns and contact hole patterns for different develop times. It was found that the process latitude, depth of focus (DOF) and exposure latitude (EL) were improved by shortening develop time for various pattern features. The characteristics of CD variation to develop time for each pattern feature agree with the suggestion in our previous paper that expanding resist process latitude was strongly correlated with the resist develop rate and that terminating the develop reaction while the resist develop rate remained large was the key to expanding the process latitude. The short develop time process contributed to the larger γ characteristics of the resist, a smaller thickness loss and also a lesser degree of surface roughness in the resist pattern, which led to an appropriate resist pattern for the semiconductor process. A novel develop application system was developed by considering the loci of movements of Dainippon Screen's (DNS) slit-scan develop nozzle and a rinse nozzle on the wafer. It was found that the novel develop application system achieved highly accurate CD controllability while realizing the benefits of the short develop time process.