Three Dimensional Microfabrication and Micromoulding

Abstract

A novel process for fabricating 3D micron-scale structures based on Rapid Prototyping (RP) principles of layer-by-layered with micrmoulds via vacuum casting / electrodeposition processes was performed. The process consists of photomask preparing and excimer laser lithography and vacuum casting / electrodeposition. With capability of excimer laser and the high replicating accuracy of vacuum casting, 3D microstructures have been fabricated. Using SU8 photoresists, a 3 layered 500 micrometer diameter micron-scale structure was fabricated, thereby demonstrating that this technique is capable of fabricating complex 3D micron-scale structures.Together with metal brass substrates machined to nanometer finishing with pulse electrodeposition in nickel solution, a nickel micromould has been fabricated. This technique helps to eliminate the time and money needed to deposit seed layer on a typical silicon substrate in order for electrodeposition to take place. Vacuum casting with silicone rubber in the micrmould fabrication can produce the micromoulds in single step by doing away with the fabrication of the mould insert, thus giving a competitive advantage over many existing techniques. A total of ten silicone rubber micromoulds were also fabricated and evaluated for its repeatability. The small deviation among the ten micromoulds themselves, as well as small deviation from the master pattern, demonstrated that this technique is suitable for mass productions