Two-step Glass Wet-etching for Micro-fluidic Devices

In this paper a two-step glass wet-etching process is presented. This process allows the fabrication of well-defined shallow recesses (typically 1-40μm) together with deep trenches or waferthrough holes (100-500μm) in the same glass wafer. The etching solutions and the masking materials used are described for the three glass types frequently used in sensor fabrication. This process is developed in such a way that anodic bonding to a second wafer is not disturbed by the wet etching process. The integration of micro-detectors in the etched micro-channels as well as the mounting of fluid connectors (capillaries) is therefore possible. In this way a complete micro-fluidic device can be realized. Keywords— glass etching, micro-channels, microfluidic devices.