Chronically Implantable Package Based on Alumina Ceramics and Titanium with High-density Feedthroughs for Medical Implants.

Implantable package to hermetically encapsulate electronics inside human body is critical for active implant devices such as neuroprothesestextbf. To meet the demanding package requirement for smaller size and higher feedthrough density, we propose a high-density (100+ feedthroughs for 10 mm diameter) ceramic/metal composite package with helium leakage rate on the 10-10 Pa m3/s, at the same time possessing the best cytotoxicity level of Grade 0, which enable the chronic implant in human. Pure alumina substrate co-sintered with platinum (Pt) paste filled in micrometer holes have demonstrated extremely good hermetical seal and biocompatibility, then its braze joint with a titanium(Ti) ring was achieved, followed by the laser welding with a Ti cap. Standard helium leakage rate and cytotoxicity experiments have shown each component and joint interface are qualified for 100-year chronic implant, which is significant for various active implant instruments.