1. A cochlear electrode array suitable for cochlear stimulation comprising: a bottom polymer layer; a first layer of patterned high density metal traces deposited on said bottom polymer layer; a polymer interlayer deposited on said bottom polymer layer and said first layer of patterned high density metal traces defining voids therein for electrodes or connections; a second layer of patterned high density metal traces deposited on said polymer interlayer; a top polymer layer deposited on said polymer interlayer and on said second layer of patterned high density metal traces defining voids therein for electrodes; electrodes deposited in said voids; said electrodes having a surface coating; wherein said top polymer layer defines openings smaller than said patterned high density metal trace; and said cochlear electrode array is curved into a three-dimensional helical shape to approximate the three-dimensional shape of the cochlea.