USING DRIE SILICON AS A CUTTING TOOL FOR HIGH PRECISION MICROMACHINING OF METAL ALLOYS

This paper reports recent advances in batch-mode micro electro-discharge machining (EDM) for high precision micromachining of metal alloys such as stainless steels. Highaspect-ratio and high-resolution silicon microstructures formed by deep reactive ion etching (DRIE) are used as cutting electrodes. These replace the previously-reported, LIGA-defined, electroplated copper electrodes, alleviating complexities associated with the LIGA process. A minimum feature size of 7 m is demonstrated on stainless steel 304 in batch-mode EDM by using DRIE Si electrodes with a width of 5 m. Features with sizes 15 m have shown excellent repeatability and uniformity across a diescale machining area of 55 mm 2 . Machining rates up to 5 m/min. have been demonstrated in micromachining of typical microfluidic structures, including arrays of channels and cavities of different sizes. Other machining characteristics are also discussed.