Patent ID: 8551271

Claim:
A method of fabricating a hermetic electrical feedthrough, the method comprising: providing a plurality of biocompatible electrochemically stable ceramic sheets having an upper surface and a lower surface; forming a plurality of via holes in said plurality of ceramic sheets extending from said upper surface to said lower surface of said ceramic sheets; stacking said plurality of ceramic sheets, wherein said via holes filled with said conductive thickfilm paste of each ceramic sheet are aligned with said via holes filled with said conductive thickfilm paste of said ceramic sheets; sandwiching said stacked plurality of ceramic sheets between an upper ceramic sheet containing no via holes and a lower ceramic sheet containing no via holes; laminating said stacked plurality of ceramic sheets with said lower ceramic sheet and said upper ceramic sheet forming a laminated ceramic substrate; inserting a biocompatible electrochemically stable conductive thickfilm paste comprised of inorganic particulate and platinum particulate into said via holes of said plurality of ceramic sheets; firing said laminated ceramic substrate to a temperature to sinter said laminated ceramic substrate, causing said ceramic sheet, said upper ceramic sheet and said lower ceramic sheet to form a single sintered structure, and causing said conductive thickfilm paste filled via holes to form metalized vias containing sintered inorganic particulate and causing said laminated ceramic substrate to form a hermetic seal around said metalized vias, the thickfilm paste being contained within the ceramic and isolated from the firing atmosphere; wherein the hermetic electrical feedthrough forms a biocompatible hermetic seal through sintering, glass melt/wetting, alloying, compounding or diffusion solution formation; grinding said upper ceramic sheet and said lower ceramic sheet to expose an upper and a lower surface of said metalized vias wherein the hermetic electrical feedthrough is suitable for implantation in a human body, said plurality of sheets comprising less than 99% aluminum oxide.