Directly patterning metal films by nanoimprint lithography with low-temperature and low-pressure

We demonstrated a new imprint method named nanoimprinting in metal/polymer bi-layer structures (NIMB) for patterning metal films with varied profiles. Converse with conventional nanoimprint lithography, the patterned mold is directly imprint in metal films not in polymer based resists. In general, direct imprint in metal films need ultra-high pressure or temperature to form patterns. In this paper, we improve the direct imprint processes by using a sharp mold and an underlying soft pad layer for the reduction of the imprint pressure and temperature. The imprint pressure can be reduced to be compatible with the conventional nanoimprint instrument. For the direct contact the metal film with mold, no surfactant should be coated on the surface of mold. It also indicates no mold-rework-processes are necessary for this direct imprint method.