Co-fired hermetically sealed feedthrough with alumina substrate and platinum filled via for an active implantable medical device

A hermetically sealed feedthrough that is attachable to an active implantable medical device, the feedthrough comprising:

• a) an alumina substrate comprised of at least 96% alumina and having a thickness extending from a body fluid side to a device side;
• b) a via hole disposed through the alumina substrate from the body fluid side to the device side;
• c) a substantially closed pore and substantially pure platinum fill disposed within the via hole and extending between the body fluid side and the device side of the alumina substrate;
• and
• d) a hermetic seal between the platinum fill and the alumina substrate,
• e) wherein the hermetic seal has a leak rate that is no greater than 1×10−7 std cc He/sec,
• f) wherein the platinum fill forms a tortuous and mutually conformal knitline or interface between the alumina substrate and the platinum fill.

A hermetically sealed feedthrough that is attachable to an active implantable medical device, the feedthrough comprising:

• a) an alumina substrate comprised of at least 96% alumina and having a thickness extending from a body fluid side to a device side;
• b) a via hole disposed through the alumina substrate from the body fluid side to the device side;
• c) a first substantially closed pore and substantially pure platinum fill disposed within the via hole and extending between the body fluid side and the device side of the alumina substrate, wherein the platinum fill forms a tortuous and mutually conformal knitline or interface between the alumina substrate and the platinum fill;
• and
• d) a hermetic seal between the first platinum fill and the alumina substrate, wherein the hermetic seal has a leak rate that is no greater than 1×10−7 std cc He/sec;
• e) a grounded via hole disposed through the alumina substrate from the body fluid side to the device side;
• f) a second substantially closed pore platinum fill disposed within the grounded via hole and extending between the body fluid side and the device side of the alumina substrate;
• and
• g) a second hermetic seal between the second platinum fill and the alumina substrate, wherein the second hermetic seal has a leak rate that is no greater than 1×10−7 std cc He/sec;
• h) at least one grounded electrode plate electrically coupled to the second grounded platinum filled via and in non-conductive relation to the first platinum filled via;
• and
• i) an outer metallization disposed on the alumina dielectric substrate and electrically connected to the plurality of grounded electrode plates.