Fabrication of high-aspect-ratio microscale mold inserts by parallel μEDM

The micro-electrical-discharge-machining (μEDM) technique is an alternative to LiGA (Lithographie, Galvanoformung, Abformung) for fabricating metal-based high-aspect-ratio microscale structures (HARMS). Traditional μEDM is a serial subtractive machining technique in which cuts are performed sequentially, and is therefore difficult to use for generating complex micropatterns on surfaces. In this paper, we report results of a hybrid microfabrication approach, combining micropattern definition with LiGA fabricated Ni HARMS with parallel micropattern generation with μEDM. Multiple micropatterns with some geometrical complexity were successfully generated in parallel on elemental Ta and 304 stainless steel. The hybrid LiGA/parallel-μEDM strategy offers a credible alternative to conventional LiGA regarding fabrication of meso- and micro- scale mold inserts, and enables them to be fabricated out of high-temperature metals/alloys not achievable with electrodeposition.