Two dimensional metallic microelectrode arrays for extracellular stimulation and recording of neurons

An inexpensive and reproducible technique for realizing metallic microelectrode arrays is presented. Arrays of sixteen microelectrodes have been fabricated using bulk silicon etching technology and photosensitive polyimide processing. The arrays are fabricated on a silicon substrate using nickel as the structural material and gold as the exposed material at the neural recording sites. Silicon nitride serves as the insulating material for the shaft of the electrodes. Individual electrodes are 15-μm thick, 25-μm wide, and 1.1 mm in length, and have a probe-to-probe spacing of 75 μm. The process used to fabricate the microelectrode arrays is compatible with standard integrated circuit fabrication technology. The arrays have successfully undergone repeated insertion into the olfactory bulb of laboratory rats