US Patent 7480988 Method and apparatus for providing hermetic electrical feedthrough

A method and apparatus suitable for forming hermetic electrical feedthroughs in a ceramic sheet having a thickness of ≦40 mils. More particularly, the method yields an apparatus including a hermetic electrical feedthrough which is both biocompatible and electrochemically stable and suitable for implantation in a patient's body. The method involves:(a) providing an unfired, ceramic sheet having a thickness of ≦40 mils and preferably comprising >99% aluminum oxide;(b) forming multiple blind holes in said sheet;(c) inserting solid wires, preferably of platinum, in said holes;(d) firing the assembly of sheet and wires to a temperature sufficient to sinter the sheet material but insufficient to melt the wires; and(e) removing sufficient material from the sheet lower surface so that the lower ends of said wires are flush with the finished sheet lower surface.