Using DRIE silicon as a cutting tool for high precision micromachining of metal alloys

Abstract

This paper reports recent advances in batch-mode micro electro-discharge machining (μEDM) 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 μm is demonstrated on stainless steel 304 in batch-mode μEDM by using DRIE Si electrodes with a width of 5 μm. Features with sizes ≥15 μm have shown excellent repeatability and uniformity across a diescale machining area of 5×5 mm2. Machining rates up to ≈5 μm/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.