Event: 3rd of 3=A Passivated Electrode Batch ?EDM Technology for Bulk Metal Transducers and Packages

Mark Richardson, Graduate Student, Univ. of Michigan
ABSTRACT: (Richardson) Batch mode micro-electro-discharge machining ( µEDM) is a lithography-compatible micro fabrication method suitable for making devices from bulk metals, including stainless steel. In high-density patterns, spurious discharges through debris can cause workpiece edge rounding, fast tool wear, and mushroom-shaped metal recasting of the tool. This paper reports a Si coating technique that acts as a discharge barrier on the sidewalls of batch Cu tools to diminish these effects. Copper tools were fabricated by electroplating into 80 µm tall SU-8 molds. The tools were then sputter coated with 500 of Ti and 1000 or 2000 of Si. The Si on the top of the tool was removed by EDM on a flat surface. As a result, discharges occurred primarily at the top of the tool during machining. This provided a 93% reduction in mean tool wear, a 78% improvement in machining depth uniformity, more vertical sidewalls, and sharper workpiece edges. These results were obtained while machining 4.5 µm wide x 25 µm tall x 1mm long unreleased stainless steel beams.
BIO: Mark Richardson was born in St. Joseph, MI in 1981. He received his BS in Electrical Engineering at the University of Michigan in 2004. He began working with Professor Yogesh Gianchandani in 2002 as an undergrad on high-aspect-ratio electroplating and the LIGA process. Now, continuing in the PhD program, his focus is on high-density batch-mode micro-electro-discharge machining for bulk metal transducers and packages.