Micro/nano-patterned metal transfer using UV-curable polymers

This study was aimed at developing a metal-transfer technique to fabricate micro/nano metal patterns by using the adhesion force between metal layers and polymer surfaces. The force was generated by partial curing on a UV-curable polymer surface. This polymer contained glycido methacrylate, polyurethane diacrylate (PU-2) and O-2-sensitive initiators, and was polymerized by covering it with an O-2-permeable film under UV irradiation. Another UV-curable polymer, containing isobonyl acrylate, hexa-acrylated PU (PU-6) and O-2-insensitive initiators, was utilized as the master mold. A layer of gold, pre-coated on the mold, was adhered to the partially cured intermediate layer, transferring gold patterns onto the intermediate layer. A scanning electron microscope, an optical microscope and atomic force microscopy were used to inspect the transferred yield and morphology of the gold patterns. A force-distance evaluation was also carried out to explore the adhesion force of the surfaces. The results show that the partially cured polymer can maintain the morphology of the pattern after a short period of irradiation and still displays its adhesive property on its surfaces. Instead of using the traditional photolithography and the lift-off process, the technique was performed to fabricate some complex patterns having micro and nano features, and interdigital electrodes, giving the potential for direct printing of microelectrodes and flexible circuits.