Fabrication of plastic microchips with gold microelectrodes using techniques of sacrificed substrate and thermally activated solvent bonding

摘要

A novel fabrication process of polymethyl methacrylate (PMMA) microfluidic chip with embedded gold microelectrodes has been developed. The PMMA chips consist of a microfluidic part, which is made by micro-milling and a mate with embedded gold electrodes made by sacrificed substrate technique. The developed sacrificed substrate technique combines photolithography, gold electrodeposition and embedding of the gold structures into a UV curable resin. Both microfluidic and electrode parts are bonded together by thermally activated solvent bonding. Isopropyl alcohol (IPA) is used as a bonding agent. Using the IPA solvent brings several advantages compared to conventional thermal bonding: (ⅰ) decreasing the bonding temperature, (ⅱ) higher bond strength. Decreasing the bonding temperature is crucial for the whole process, because of prevention of electrode cracking, microfluidic channel deformation and clogging. Higher bond strength prevents a liquid leakage and generally improves the microdevice durability. The fabrication process was successfully tested in construction of a four-electrode AC micro-conductometer.