Realization of various sub-micron metal patterns using room temperature nanoimprint lithography

Nanoimprint lithography (RT-NIL) process using hydrogen silsesquioxane (HSQ) provides a simple fabrication method to realize sub-micron-sized patterns because it can be applied at room temperature. When the process is performed on a HSQ–PMMA bi-layer resist, it is suitable to additional metal sputtering and lift-off process because it features negative vertical profiles. However, high viscosity of HSQ at room temperature requires a high imprint pressure, and also limits the applicable mold profile. Thus, the HSQ imprint depth dependencies on prebaking temperature and mold protrusions are investigated and results are analyzed using the equations for squeezed flow of polymers which enable us to predict typical imprint results under specific conditions. Based on these investigations, the RT-NIL process was optimized and, then, various sub-micron-sized metal patterns of line and hole array were fabricated.