Microfabrication by hot embossing and injection molding at LASTI

Abstract

LIGA process includes three processes as X-ray lithography, electroforming to fabricate metalic molds and replication, and can be fabricated nano and micro parts for various devices that it is difficult to product by conventional machining methods. A key technology which gathers mass-production efficiency in the LIGA process is micro-replication technology. We choiced hot embossing and injection molding methods for replication. For a demonstration, two kinds of Ni molds, a mesh pattern within a line width of 100 μm, and an aspect ratio of 1.0 and a mesh pattern within a line width of 40 μm, and an aspect ratio of 2.5, were prepared. These were produced with X-ray lithography and nickel electrofoming technique. In hot embossing, an experiment of micro-replication using polymethyl methacrylate (PMMA) and polycarbonate (PC) sheets succeeded. At injection molding, it could not transfer well with PMMA and PC, but injection temperature was set up highly, and it succeeded by cycloolefin polymer. Furthermore, we measured sidewall’s surface roughness of microstructures produced at each steppes of the LIGA process, and it checked that the LIGA process had processing accuracy higher than a conventional machining method.