Electrical evaluation of copper damascene interconnects based on nanoimprint lithography compared with ArF immersion lithography for back-end-of-line process

Abstract

Nanoimprint lithography (NIL) is promising for processing of dual damascene structures fabricated in back-end-of-line layers and initial development began with a simple single-level process to evaluate NIL’s suitability. In this work, test element group (TEG) pattern with a 70 nm half-pitch was selected, and copper filling and chemical-mechanical polishing were performed after NIL pattern transfer. The results were compared with those obtained from the same TEG layout and processes except using ArF immersion lithography instead of NIL. Those obtained by NIL showed high pattern fidelity for all designed layouts, whereas the resist patterns varied from the designed shape for ArF immersion lithography. The line resistances of Cu interconnects patterned by NIL showed good cumulative distributions at linewidths ranging from 60 nm to 78 nm in 2 nm increments without line breaks or space narrowing of SiO2. NIL showed potential for interconnect patterning with high-precision linewidth control.