Bottom-Anti-Reflective coatings (BARC) for LFLE Double patterning process

Double patterning process with ArF immersion lithography has been developed as one of the most promising candidate for hp32 node and beyond. However complicated process flow and cost of ownership are the critical issue for this process. LELE (Litho-Etch-Litho-Etch) is the one of the standard process, but in order to reduce the process and cost, that LFLE(Litho-Freezing-Litho-Etch) and LLE (Litho-Litho-Etch) process have been investigated as the alternative process. In these processes, Organic Bottom-Anti-Reflective coating (BARC) is used two times with same film in both 1 st Litho and 2 nd Lithography process. In 2 nd Lithography process, resist pattern will be printed at space area where exposed and developed in 1 st lithography process. Therefore, organic BARC needs to have process stability in Photo and development step to keep good litho performance between 1 st and 2 nd lithography in LFLE / LLE process. This paper describes the process impact of 1 st exposure and development for organic BARC, and the LFLE / LLE performance with optimized organic BARC will be discussed.