Complex L/S and via patterning for damascene interconnects using nanoimprint lithography

Nanoimprint lithography (NIL) is a promising technique for fabricating dual damascene structures, which are commonly required in back-end-of-line layers. NIL allows precise pattern transfer from mold (template) patterns, and is especially effective for making complex patterns, such as mixtures of dense line-and-space (L/S) patterns and isolated vias without complicated optical pattern collection. In this work, we demonstrate the complex patterning of L/S and isolated vias using NIL, and compare them with those obtained using ArF immersion lithography. Mixed patterns of high-density L/S lines and isolated vias with a half-pitch of 32nm were perfectly patterned using NIL. By further improvement of the mold fabrication process, we successfully obtained complex L/S and isolated via patterns with a half-pitch of 24nm.