Multi-hundred or thousand channel electrode electrophysiological array and fabrication method

A method for fabricating a flexible electrode array with hundreds or thousands channels for clinical use comprising:

• providing a rigid carrier substrate;
• depositing a release layer on the carrier substrate;
• depositing a first thin flexible layer of non-conductive biocompatible polymer on the release layer;
• forming a pattern of elongate metal leads and electrode sites and pad sites at opposite terminal ends of the metal leads;
• forming electrochemically active material on the electrode sites;
• forming an etch stop layer on the electrochemically active material;
• depositing a second thin flexible layer of non-conductive biocompatible polymer over the pattern;
• depositing a mask and patterning the mask with openings at the electrode and connector sites and at perfusion sites adjacent the electrode sites;
• etching to open vias to the etch stop layer at the electrodes sites and through the first and second thin flexible layer at the perfusion sites to create perfusion holes;
• removing the mask;
• releasing the flexible electrode array from the carrier substrate.