Examining strategies to control gel-like defects in EUV patterning materials

EUV chemically amplified resists (CAR) use a copolymer containing highly-polar poly hydroxy styrene (PHS), which is believed to easily aggregate and form gel-like polymers. These aggregates likely generate microbridge defects, an important yield detractor in leading-edge semiconductor manufacturing. Improvements in EUV photoresist quality and a reduction in on wafer defectivity require more selective removal for this specific contamination source. Earlier presentations have demonstrated the benefit of effective removal of gel-like polymers in ArF immersion photoresists using photochemical filters with functionalized membrane technology [1]. In this paper we introduce a new filter technology for gel-like polymer removal in EUV photoresists. This contamination control technology demonstrates improved efficiency for removing partial, highly polar chemicals and fine particles that cause gel-like polymers over previous filter generations. The filter also improves on wafer defect counts.