New sectorized implantable microelectrode fabrication, packaging and ageing for neural sensing and stimulation

This paper describes the fabrication and the packaging of a flexible parylene-based multi-contact electrode embedded in a silicone-based cuff. This type of electrode is well suited for peripheral nerve recording and offers improved spatial selectivity. We conducted mechanical and electrical tests for assessing the reliability by using an accelerated lifetime protocol. Test structures made with platinum sandwiched with parylene C were designed. The accelerated lifetime soaking tests in phosphate buffered saline (PBS) solution at 67°C showed a longer life time (approximatively 4.5 years) with a dehydration bake introduction in the process flow and a parylene thickness increase. A specific test bench was developed for the mechanical cycling and for evaluating the mechanical robustness of the thin film devices.