Applications of LIGA on Micro-Punching Process for Metallic Materials

This study presents an innovative imprinting method to fabricate IC devices by micro-punch process. Normally, imprinting method is used to imprint plastic materials such as photoresist and polymeric materials. In this study, imprinting process is applied to micro-punch metallic materials directly for IC devices. Fabrications of IC devices with high aspect ratio structures ranging from micrometer to sub-micrometer are described. In this study, to keep the production costs as low as possible, a complete micro-punching process is applied to replicate IC devices. A combination of lithography, extra-hard alloy nickel cobalt (Ni/Co) electroplating process (as a metal imprint mold for punch) and chemical mechanic polishing (CMP) process is used to flat the extra-hard alloy micro-punch head. It is worth noticing that the Ni-Co electroplating process with hardness over Hardness of Vicker (Hv) 560 is developed. With such hardness, it can stand the high pressure and abrasivness to confine the accuracy during micro-punching process. With regard to the electroplating process, Ni-Co is deposited and covered on the photoresist template uniformly by electroplating. The Ni/Co mold is served as master for micro-punching process to replicate the pattern onto polyimide (PI) or copper sheets. Finally, the experimental results are measured and characterized.