US Patent 7877866 Flexible circuit electrode array and method of manufacturing the same

A method of manufacturing a flexible circuit electrode array that provides excellent adhesion between the polymer base layer and the polymer top layer and insulation of the trace metals and electrodes. A layer of polymer is laid down. A layer of metal is applied to the polymer and patterned to create electrodes and leads for those electrodes. A second layer of polymer is applied over the metal layer and patterned to leave openings for the electrodes, or openings are created later by means such as laser ablation. Hence the array and its supply cable are formed of a single body. Alternatively, multiple alternating layers of metal and polymer may be applied to obtain more metal traces within a given width.