# US 2014/0194964 A1 · Low impedance oxide resistant grounded capacitor for an aimd > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194964 A1 - Document ID: US20140194964A1 - Status: Published application - Kind: A1 - Application number: 14/202,653 - Filed: 2014-03-10 - Published: 2014-07-10 - Earliest claimed: 2008-03-20 - Assignees: Greatbatch Ltd. - Applicants: Greatbatch Ltd. - Inventors: Jason Woods; Richard L. Brendel; Robert A. Stevenson; Christopher M. Williams; Robert Naugler; Christine A. Frysz - Web page: https://patentgrep.com/patent/US20140194964A1 ## CPC - A61N 1/3754: {Feedthroughs} - H01G 2/02: Mountings - H01G 4/228: Terminals - H01G 4/35: Feed-through capacitors or anti-noise capacitors - H01G 4/40: Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations - H01R 13/7195: with planar filters with openings for contacts - H03H 1/0007: {of radio frequency interference filters} - H03H 7/1766: {Parallel LC in series path (H03H7/1783 takes precedence)} - H03H 2001/0042: {Wound, ring or feed-through type capacitor} - H03H 2001/0085: {Multilayer, e.g. LTCC, HTCC, green sheets} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10) - H01R: ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A hermetically sealed filtered feedthrough assembly for an AIMD includes an insulator hermetically sealed to a conductive ferrule or housing. A conductor is hermetically sealed and disposed through the insulator in non-conductive relation to the conductive ferrule or housing between a body fluid side and a device side. A feedthrough capacitor is disposed on the device side. A first low impedance electrical connection is between a first end metallization of the capacitor and the conductor. A second low impedance electrical connection is between a second end metallization of the capacitor and the ferrule or housing. The second low impedance electrical connection includes an oxide-resistant metal addition attached directly to the ferrule or housing and an electrical connection coupling the second end metallization electrically and physically directly to the oxide-resistant metal addition. ## Claims ### Claim 1 A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising: an insulator hermetically sealed to a conductive ferrule or housing; a conductor hermetically sealed and disposed through the insulator in non-conductive relation to the conductive ferrule or housing between a body fluid side and a device side; a feedthrough capacitor located on the device side, the feedthrough capacitor comprising a first and a second end metallization, wherein the first end metallization is connected to at least one active electrode plate and wherein the second end metallization is connected to at least one ground electrode plate, wherein the at least one active electrode plate is interleaved and disposed parallel to the at least one ground electrode plate, wherein the at least one active and ground electrode plates are disposed within a capacitor dielectric; a first low impedance electrical connection between the first end metallization and the conductor; and a second low impedance electrical connection between the second end metallization and the ferrule or housing, wherein the second low impedance electrical connection comprises an oxide-resistant metal addition attached directly to the ferrule or housing and an electrical connection coupling the second end metallization electrically and physically directly to the oxide-resistant metal addition. ### Claim 2 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition comprises a different material as compared to the ferrule or housing. ### Claim 3 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition comprises a noble metal. ### Claim 4 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition comprises gold, platinum, palladium, silver and combinations thereof. ### Claim 5 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition is laser welded to the ferrule or housing. ### Claim 6 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition comprises a brazed metal. ### Claim 7 (depends on 6) The assembly of claim 6, wherein the brazed metal oxide-resistant metal addition comprises gold, gold-based metal, platinum, platinum based metal, palladium, palladium based metal, silver, silver based metal, gold-palladium, gold-boron, and palladium-silver ### Claim 8 (depends on 1) The assembly of claim 1, wherein a grounding loop is defined on the device side comprising the first low impedance electrical connection and the second low impedance connection from the conductor through the feedthrough capacitor to the ferrule or housing. ### Claim 9 (depends on 8) The assembly of claim 8, wherein the total resistance of the grounding loop is less than 1 milliohm. ### Claim 10 (depends on 8) The assembly of claim 8, wherein the total inductance of the grounding loop is less than 10 nanohenries. ### Claim 11 (depends on 8) The assembly of claim 8, wherein the total inductance of the grounding loop is less than 1 nanohenries. ### Claim 12 (depends on 1) The assembly of claim 1, wherein the conductor comprises a leadwire. ### Claim 13 (depends on 12) The assembly of claim 12, wherein the leadwire comprises platinum, palladium, silver or gold. ### Claim 14 (depends on 1) The assembly of claim 1, wherein the insulator is flush with the ferrule or housing on the device side. ### Claim 15 (depends on 1) The assembly of claim 1, wherein the insulator comprises an alumina substrate comprised of at least 96% alumina and the conductor comprises a substantially closed pore and substantially pure platinum fill disposed within a via hole and extending between the body fluid side and the device side of the alumina substrate. ### Claim 16 (depends on 15) The assembly of claim 15, including a hermetic seal between the platinum fill and the alumina substrate, wherein the platinum fill forms a tortuous and mutually conformal knitline or interface between the alumina substrate and the platinum fill, wherein the hermetic seal has a leak rate that is no greater than 1×10−7 std cc He/sec. ### Claim 17 (depends on 16) The assembly of claim 16, wherein an inherent shrink rate during a heat treatment of the alumina dielectric substrate in a green state is greater than that of the platinum fill in the green state. ### Claim 18 (depends on 1) The assembly of claim 1, wherein the oxide-resistant metal addition comprises a wire, a pad, an L-shaped pad or an L-shaped pad with cutouts. ### Claim 19 (depends on 1) The assembly of claim 1, including a ground wire disposed through both the insulator and the feedthrough capacitor, where the ground wire is not electrically coupled to the at least one active and ground electrode plate. ### Claim 20 (depends on 19) The assembly of claim 19, wherein the ferrule or housing comprises an integrally formed conductive peninsula, where the ground wire is electrically coupled to the peninsula. ### Claim 21 (depends on 1) The assembly of claim 1, wherein the feedthrough capacitor comprises a resonant frequency above 400 MHz. ### Claim 22 (depends on 1) The assembly of claim 1, wherein the feedthrough capacitor comprises a capacitance of between 300 picofarads and 10,000 picofarads. ### Claim 23 A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising: an insulator hermetically sealed to a conductive ferrule; a conductor hermetically sealed and disposed through the insulator in non-conductive relation to the conductive ferrule between a body fluid side and a device side; a feedthrough capacitor located on the device side, the feedthrough capacitor comprising a first and a second end metallization, wherein the first end metallization is connected to at least one active electrode plate and wherein the second end metallization is connected to at least one ground electrode plate, wherein the at least one active electrode plate is interleaved and disposed parallel to the at least one ground electrode plate, wherein the at least one active and ground electrode plates are disposed within a capacitor dielectric; a first low impedance electrical connection between the first end metallization and the conductor; an oxide-resistant metal addition attached directly to the ferrule; and a second low impedance electrical connection coupling the second end metallization electrically and physically directly to the oxide-resistant metal addition. ### Claim 24 A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising: a ferrule comprising a conductive peninsula or extension; an insulator hermetically sealed to the conductive ferrule; a conductor hermetically sealed and disposed through the insulator in non-conductive relation to the conductive ferrule between a body fluid side and a device side; a feedthrough capacitor located on the device side, the feedthrough capacitor comprising a first and a second end metallization, wherein the first end metallization is connected to at least one active electrode plate and wherein the second end metallization is connected to at least one ground electrode plate, wherein the at least one active electrode plate is interleaved and disposed parallel to the at least one ground electrode plate, wherein the at least one active and ground electrode plates are disposed within a capacitor dielectric; a first low impedance electrical connection between the first end metallization and the conductor; a ground conductor disposed through the feedthrough capacitor in non-conductive relation with the at least one ground and active electrode plates, where the ground conductor is electrically coupled to the conductive peninsular or extension; and an oxide-resistant metal addition attached directly at one end to the ground conductor and connected at the other end to the second end metallization of the feedthrough capacitor.