In this work we investigated the properties of HSQ
and PMMA resists focusing on contrast and line width for ebeam
lithography (EBL) application. HSQ was found to be a
good candidate to have desired line widths but the contrast we
obtained was less than it was for PMMA. Since the fluorine based
plasma does not have high selectivity over exposed HSQ, we
propose a PMMA/HSQ bi-layer resist stack as a hard mask to
etch Si selectively. Using this technique, 50nm deep Si fins may
be patterned.