Abstract
We investigated the removal characteristics of an ultraviolet (UV) curable polymer for UV nano-imprint lithography (NIL) using atomic hydrogen, which was generated by the catalytic decomposition of H2 molecules in H2/N2 mixed gas (H2:N2=10:90vol.%) using a tungsten hot-wire catalyzer. The cured polymers were removed by atomic hydrogen without a residual layer. The removal rate of the polymer increased with rising catalyzer temperature. It was assumed that both enhanced reactivity between atomic hydrogen and polymer by the substrate temperature increase due to radiation heat of the catalyzer and increased atomic hydrogen concentration occurred as a result of the rise in catalyzer temperature. When the distance between the catalyzer and the substrate was 100mm, the catalyzer temperature was 2400°C, and the initial substrate temperature was room temperature, the removal rate of polymers was 0.17μm/min independent of exposure dose to the polymer. The removal rate of polymers was comparable to the removal rate of general i-line positive-tone novolak resist. The polymer adhering to the micro-asperity portion of the mold was removed without leaving a residual layer by grazing-incidence atomic hydrogen.
