20 nm Line/space patterns in HSQ fabricated by EUV interference lithography

An evaluation of hydrogen silsesquioxane (HSQ) for EUV lithography is presented. The effects of bake temperature and developer concentration on the ultimate resolution, sensitivity and contrast are investigated. It is demonstrated that HSQ as a negative-tone photoresist provides patterns with half-pitches as small as 20 nm with EUV interference lithography. SEM micrographs show that the low line-edge roughness of the patterns is accompanied with the high-quality cross-sectional profiles. This high resolution and pattern quality are achieved through development in high-concentration developers for long development times, which is in line with previous results obtained with e-beam lithography.