This paper describes characterization of thermal imprinting of resins using a fabricated micro-multi-fin structured micro-electro-mechanical system（MEMS）mold to incorporate a structural color expression function.

Through the MEMS fabrication process, micro-mold structures with 0.2-μm pitch inclined micro-multi-fin structures on the sidewalls of microscale ridges（structures resembling a morpho butterfly）were fabricated on Si substrates. Shape transfer properties related to thermal imprinting of cycloolefin polymer（COP）and polymethyl methacrylate（PMMA）were examined using the fabricated MEMS mold with an inclined multi-fin structure. Thermal imprinting was conducted under various temperature conditions related to the measured glass transition points of resins obtained via dynamic mechanical analysis. The multi-fin shape（a 4-μm pitch ridge structure with a 0.2-μm pitch inclined multi-fin structure）was transferred to the COP and PMMA. The molding resin fin widths increased along with increasing molding temperature. Also, adhesion between the mold and the resin improved, which made release of the resin from the mold difficult. Finally, the imprinted PMMA exhibited a light blue reflection（380-500 nm）.