Solder-free miniaturized interconnection technology for neural interfaces

Miniaturized implantable medical devices for neural recording and stimulation often feature high numbers of electrical channels. Cutting-edge assembly technology is offering ways to drastically miniaturize reliable implantable electronics and is enabling small pitch electrode access to neural tissue. However, in many applications, it is still necessary to interconnect these two parts of an implanted system to metal wires and cables. The presented work focuses on connecting these macro-components to modern features like high density electrical feedthroughs without compromising the achievements in miniaturization of the latter. In a first attempt on exploiting this technology a sample was produced featuring 41 MP35N wires being mechanically and electrically connected to pads at an integration density of more than 490 contacts/cm². The electrical and mechanical behavior illustrate the feasibility of this concept and highlight the need for further improvements to guarantee stable operation in the demanding regime of active implantable medical devices.