Revealing beam-induced chemistry using modulus mapping in negative-tone EUV/e-beam resists with and without cross-linker additives

One of the key challenges to high resolution resist patterning is probing the resist properties at length scales commensurate with the pattern size. Using a new scanning probe microscopy (SPM), Peak Force™ tapping, we map exposure dependent nanoscale modulus of the exposed/developed resist patterns with sub-10 nm resolution. By innovative electron beam exposure pattern design, the SPM technique reveals that resist modulus follows the height contrast profile, but with a shift to higher exposure doses. SEM image analysis of patterned resist structures confirm that the best line-space patterns are achieved at exposure dose where modulus reaches its maximum and shows how modulus can be used to probe patternability of resist systems.