Fabrication of sub-micron 3-D structure using duo-mold UV-RIL process

3-D polymeric micro- and nano-structures were fabricated by the reversal imprint lithography technique using nano-patterned molds. A surface-treated quartz mold and a water-soluble poly vinyl alcohol (PVA) mold were used to make dual-side patterned, 2-D polymeric, micro- and nano-structures. First, UV-curable, polymeric resin was dropped onto the quartz mold, which was then covered with the PVA mold. The two stacked molds were pressed and exposed to UV-light to cure the resin. The cured polymeric resin (the reversal layer) was easily released from the quartz mold, because the surface of the latter was treated with an anti-stiction layer. The reversal layer, bound to the PVA mold, was transferred to a Si substrate by applying a thin layer of a UV-curable bonding agent. After bonding the reversal layer, the PVA mold was selectively removed by dipping in water. As a result, the dual-side patterned, thin polymeric 2-D structure was formed on the silicon substrate and, by repeating this process, 2-D nano-structures were stacked to form a 3-D nano-structure. By making use of the anti-stiction-treated, quartz mold and the water-soluble characteristic of the PVA material, the reliable release of the reversal layer was achieved.