Research On C-MEMS Technology For Fabricating Biochip Carbon Microelectrodes

Biochip technology is a leading-edge and multidisciplinary technology which combines biology technology, material science, surface chemistry, nanotechnology and information technology etc. The design and fabrication of special microelectrodes is the key to the dielectrophoresis (DEP) chip technology, which is one important kind of biochip technology. The fabrication of conventional microelectrodes (usually several hundreds nanometers) for DEP chip involves complex technologies like deposition, photo lithograph and etching, which require costly equipment and high cost of material.In this work we present a novel method of fabricating biochip carbon microelectrodes named C-MEMS technology. Photo resist that is broadly used in semiconductor industry is photo lithographed to silicon substrate and pyrolized in high temperature under oxygen-free atmosphere of N2 and N2/H2 forming gas. The resulting film is called carbon-pyrolyzed photoresist film (C-PPF). Both the basic theory of C-MEMS technology and the microcosmic mechanism of pyrolized photoresist were carefully studied, and the effect of technical parameters such as temperature, atmosphere, lithograph to the performance of the C-PPF films was discussed. C-PPF films with excellent conductivity ( with resist of 4×10-3Ω? cm), high resolution, good coherence, and low roughness were fabricated by C-MEMS technology. In addition, C-MEMS microelectrodes for convetional DEP (cDEP) chip, traveling wave DEP (TWD) chip and electrorotation (ROT) chip were designed based on DEP theory and fabricated by C-MEMS technology, respectively. Three-dimensional C-MEMS post arrays with thickness of 7μm were also produced by pyrolizing SU 8 photoresist. From our work, C-PPF film was proved to be highly conductive, bio-compatible and chemically stable. The C-MEMS technology shows advantages of simple process, low cost, capability of fabricating three-dimensional microelectrodes and massive production, and will have great value in biochip and electrochemical fields.