A novel fabrication method of Parylene-based microelectrodes utilizing inkjet printing

Abstract

We report a novel fabrication method of creating thin flexible Parylene-based microelectrodes. The fabrication technique described here is based on inkjet printing and thus does not require conventional photolithography and thin-film deposition processes. First, silver microelectrodes are printed on poly-dimethylsiloxane (PDMS) spin-coated on a silicon wafer. Then a thin Parylene layer is deposited on top of the PDMS layer followed by peeling-off. The silver microelectrode patterns are flawlessly transferred to the Parylene film during this process. Finally, sintering of the silver pattern is achieved in vacuum oven. Narrow (40–100μm) silver microelectrodes were perfectly transferred from PDMS onto Parylene film without structural damages or significant drop in electrical resistance (Note that direct printing of silver microelectrode patterns on Parylene is very challenging due to the surface property of Parylene.). In fact, the silver microelectrodes transferred onto Parylene showed lower electrical resistance and better adhesion than the original silver microelectrodes printed on PDMS. In order to demonstrate the utility of thin flexible Parylene-based silver microelectrodes, we fabricated diverse microelectrodes and conducted dielectrophoretic (DEP) manipulation of microbeads with them. We believe that this rapid and low-cost fabrication method of creating thin flexible Parylene-based microelectrodes can be used in a variety of applications in flexible electronics, neural engineering, medical implants as well as MEMS and lab on a chip.