A method for manufacturing a flexible circuit electrode array, comprising: a) depositing a metal trace layer containing a base coating layer, a conducting layer and a top coating layer on said insulator polymer base layer； b) applying a layer of photoresist on said metal trace layer and patterning said metal trace layer and forming metal traces on said insulator polymer base layer； c) activating said insulator polymer base layer and depositing a top insulator polymer layer and forming one single insulating polymer layer with said base insulator polymer layer； d) applying a thin metal layer and a layer of photoresist on the surface of said insulator polymer layer and selective etching said insulator layer and said top coating layer to obtain at least one via； and e) filling said via with electrode material. 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. The method provides an excellent adhesion between the polymer base layer and the polymer top layer and insulation of the trace metals and electrodes.
