The application of EUV lithography for 40nm node DRAM device and beyond

Extreme ultraviolet lithography (EUVL) is one of the leading candidates for next-generation lithography technology for the 32 nm half-pitch node and beyond. We have evaluated the Alpha Demo Tool(ADT) characterizing for mixed-andmatched overlay(MMO), flare noise, and resolution limit. For process integration, one of the important things in EUVL is overlay capability. We performed an overlay matching test of a 1.35NA and 193 immersion tool using a low thermal expansion material(LTEM) mask. We also investigated the flare level of the EUV ADT for device applications. The current EUV tool has a higher flare level than ArF lithography tools. We applied a contact layer for 40nm node device integration to reduce the variation in critical dimension(CD) from the flare noise.