Cost-Effective Sub-20 nm Lithography: Smart Chemicals to the Rescue

The increasing cost of the lithographic process, which is driven both by process complexity and by the increasing price of moving to smaller exposure wavelengths, makes approaches that use "smart chemicals" and "bottom up" patterning processes that employ molecular scale assembly processes ever more attractive. The technology that is closest to implementation in IC manufacturing is directed self-assembly (DSA) of block copolymers for contact hole shrink and line space multiplication. The current delays and limitations in EUV lithography provide further incentive to pursue DSA technology, which can be both complementary (such as in contact shrink) as well as a competitor (such as for fine line patterning). Current results indicate that DSA structure quality, line roughness measures, and defectivity are in a range that allows development work for integration into existing production to begin. Contact hole shrink may be closest to implementation, since its process integration is very similar to existing shrink material schemes. A first application for line frequency multiplication may be the replacement of multiple patterning processes with DSA schemes which have the potential to provide compelling cost and technical advantages.