Micromachined silicon electrodes for electrochemical micromachining

C. Blattert (a), C. Müller (b), H. Reinecke (a),(b)

(a) Hahn-Schickard-Gesellschaft e. V. Institute for Micromachining and Information Technology (HSG-IMIT),Villingen-Schwenningen, Germany
(b) Laboratory for Process Technology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany

Abstract

Piracy and counterfeiting as well as retraceability demands of products such as plastic parts or tablets require new and innovative methods for unique product identification. An opportunity is the placement of microstructured codes in moulding tools. These tools are often made from materials that do not allow for highly precise micromachining by traditional technologies. Electrochemical machining (ECM) is a method for structuring construction materials such as steel or titanium. The current paper presents a new technology for the fabrication of microstructured tool electrodes for electrochemical machining by using highly doped silicon as electrode material. A simple and low priced fabrication of microstructured silicon electrodes with locally isolated areas is demonstrated by using wellestablished silicon processing technologies. Prototypes based on this new tool electrode technology are fabricated. Therewith electrochemical machining of microstructures in stainless steel is successfully demonstrated. Machining gaps down to 10 μm and average surface roughness of 60 nm are achieved. Typical rates of removal between 60 - 240 μm/min are reached. The local isolation of electrode areas advances the machining accuracy.