Micromachined electrodes for high density neural stimulation systems

High-resolution retinal prosthetic systems require high-density stimulation electrodes to restore the vision of blind patients suffering from retinitis pigmentosa and macular degeneration. Micromachining the surface of electrodes to obtain high aspect ratio features can tremendously increase the effective area of the electrode. A unique process has been developed to obtain high aspect ratio structures by plating on the sidewall of recently developed and insufficiently rinsed resist. A quadrupling of the effective area of the electrode surface has been achieved with modest micromachining and should translate into a similar improvement in visual resolution.