Incorporation of direct current superposition as a means for high quality contact and slotted contact structures utilizing litho-freeze-litho-etch

Incorporation of litho-freeze-litho-etch (LFLE) double patterning techniques have had limited uses in the industry due to a number of issues including : LER / LWR degradation of 1st layer patterning during the 2nd exposure, the necessity to utilize thermal ‘freezing’ resists which necessitate the incorporation of alcohol-based resist systems, and the inability of extending such processes to NTD resist platforms which have superior patterning capabilities for specific structures which are attractive for LFLE type of applications.