Patterning of sub-50 nm dense features with space-invariant 157 nm interference lithography

We have implemented a space-invariant interference lithography tool for 157 nm F2 lasers, capable of creating dense line and space patterns with a spatial period of 91 nm. No gratings or curved optics are required, allowing a simple and inexpensive tool for resist and process development at 157 nm. Initial patterning of several commercial and experimental resists has resulted in high contrast features with little line edge roughness and good cross-sectional profiles, indicating that the fundamental performance of acid-catalyzed resists patterned at 157 nm may meet lithography requirements for sub-50 nm features.