Double exposure using 193nm negative tone photoresist

Abstract

ABSTRACT Double exposure is one of the promising methods for extending lithographic patterning into the low k 1 regime. In this paper, we demonstrate double patterning of k 1-effective =0.25 with improved process window using a negative resist. Negative resist (TOK N-series) in combination with a bright field mask is proven to provide a large process window in generating 1:3 = trench:line resist features. By incorporating two etch transfer steps into the hard mask material, frequency doubled patterns could be obtained