A novel 3D flexible parylene-metal structure fabrication technique

Flexible microelectrode array (MEA) has been widely used in neural prosthesis, such as artificial retinal chip. Specially, this sort of MEA for highly efficient electrical stimulation is more urgently required. In this work, a 3D flexible parylene-metal structure was fabricated by structure transfer technique. Silicon wafer was etched by deep reactive ion etching and isotropic wet etching sequentially. The so-etched 3D silicon structure was replicated by the parylene with/without metal depositions that followed. After releasing these functional films from the silicon mold, a 3D flexible parylene-metal structure was obtained. A numerical simulation was used to compare the stimulating performance of the 3D electrode and the planar one. The results indicated that the 3D flexible microelectrodes prepared by the present technique could enhance electrical stimulation characteristics considerably, which made it a promising candidate to prepare a high quality artificial retinal chip.