High-voltage filtered feedthrough assembly having a filter capacitor grounded to a gold pad nested in a ferrule pocket of the feedthrough for an active implantable medical device (AIMD)
The high-voltage and high-frequency pulse dielectric breakdown strength (DBS) of an implantable medical device is increased by positioning insulation materials on or adjacent to the external surfaces of a filter capacitor. Dielectric breakdown strength is further increased by adding polymeric or ceramic nanoscale metal oxide insulative powders to the insulation materials. The filter capacitor is grounded to the ferrule of a feedthrough through a gold pocket-pad nested in a recessed pocket of the ferrule.
1 . A filtered feedthrough assembly that is attachable to an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
a feedthrough, comprising:
i) An electrically conductive ferrule comprising:
A) a ferrule sidewall defining a ferrule opening, the ferrule sidewall having a ferrule height extending to a ferrule body fluid side surface spaced from a ferrule device side surface;
B) at least one recessed pocket having a depth extending from the ferrule device side surface part-way through the height of the ferrule toward the ferrule body fluid side surface; and
C) an oxide-resistant pocket-pad nested in the at least one recessed pocket so that the pocket-pad is electrically connected to the ferrule; and
ii) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator extending to an insulator body fluid side spaced from an insulator device side, wherein, when the ferrule hermetically sealed to the insulator is attached to an opening in a housing of an AIMD, the ferrule body fluid side adjacent to the insulator body fluid side, and the ferrule device side adjacent to the insulator device side reside outside and inside the AIMD, respectively; and
iii) at least a first terminal pin hermetically sealed to the insulator in a first via hole by a first braze, wherein the first terminal pin extends outwardly beyond at least the insulator device side; and
b) a filter capacitor, comprising:
i) a dielectric substrate having a dielectric substrate peripheral surface extending to a dielectric substrate first end surface and an opposed dielectric substrate second end surface that is spaced above the ferrule device side surface, wherein the dielectric substrate supports at least one active electrode plate interleaved in a capacitive relationship with at least one ground electrode plate extending to the dielectric substrate peripheral surface, and wherein the dielectric substrate first end surface is adjacent to the insulator and the ferrule device sides; and
ii) at least a first passageway extending through the dielectric substrate to the dielectric substrate first and second end surfaces, wherein the first terminal pin extends through the first passageway and outwardly beyond the dielectric substrate second end surface, the first terminal pin being electrically connected to the at least one active electrode plate in the first passageway;
c) an external ground metallization contacting the at least one ground electrode plate at the peripheral surface,
d) an electrical connection material connecting from the external ground metallization to the oxide-resistant pocket-pad connected to the ferrule; and
e) a first polymeric insulating material contacted to the dielectric substrate second and surface and the external ground metallization at the dielectric substrate peripheral surface, wherein the polymeric insulating material comprises insulating nanoparticles.
2 . The filtered feedthrough assembly of claim 1 ; wherein the first polymeric insulating material contacted to the dielectric substrate second end surface also contacts the external ground metallization at the dielectric substrate peripheral surface.
3 . The filtered feedthrough assembly of claim 1 , wherein the first polymeric insulating material contacted to the external ground metallization at the dielectric substrate peripheral surface also contacts the oxide-resistant pocket-pad nested in the at least one recessed pocket of the ferrule.
4 . The filtered feedthrough assembly of claim 1 , wherein a second polymeric insulating material as a second washer is positioned between the insulator device side and the dielectric substrate first end surface, and wherein the second polymeric washer has at least a washer first opening through which the first terminal pin extends.
5 . The filtered feedthrough assembly of claim 4 , wherein the second polymeric insulating material comprises insulating nanoparticles.
6 . The filtered feedthrough assembly of claim 1 , wherein the oxide-resistant pocket-pad is selected from gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, tungsten, niobium, zirconium, vanadium, platinum-rhodium, platinum-iridium, platinum-palladium, platinum-gold, platiniridium (platinum-iridium), iridiosmium and osmiridium (iridium-osmium), gold-palladium, gold-boron, palladium-silver, and combinations thereof.
7 . The filtered feedthrough assembly of claim 1 ; wherein the at least one recessed pocket is a continuous recessed pocket surrounding the ferrule opening and the oxide-resistant pocket-pad is nested in the continuous recessed pocket.
8 . The filtered feedthrough assembly of claim 1 , wherein there are a plurality of recessed pockets at spaced locations about the ferrule opening and an oxide-resistant pocket-pad is nested in each of the plurality of recessed pockets.
9 . The filtered feedthrough assembly of claim 1 , wherein the polymeric insulating material is selected from silicone, polyurethane, polyester, polyethylene, polypropylene, polyimide, polyamide, acrylic, polyacrylates, perfluoroalkoxy (PFA), fluorinated ethylene-propylene (FEP), polyetheretherketone (PEEK), polyamide imide (PAI), polyphenyl sulfone (PPSU), polyetherimide (BEI), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyoxymethylene (POM), polystyrene (PS), thermoplastic elastomer (TPE), polyethylene terephthalate (PET), ethylene-vinyl acetate (EVA), polyethylene-vinyl acetate (PEVA), polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), polyoxymethylene (POM) polycarbonate (PC), epoxy, rubber, acetal, polyacetal, polyformaldehyde, phenolic, polysulfide, and combinations thereof.
10 . The filtered feedthrough assembly of claim 1 , wherein the nanoparticles are selected from Al 2 O 3 , BaO, CaO, CeO 2 , MgO, ZnO, ZrO 2 , SiO 2 , TiO 2 , Al 2 SiO 53 , BaTiO 3 , SrTiO 2 , zirconia toughened alumina (ZTA), alumina toughened zirconia (ATZ), yttrium stabilized zirconia (YSZ), yttrium-toughened zirconia (YTZP), aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), boron nitride (BN), carbon nitride (CN), and combinations thereof.
11 . The filtered feedthrough assembly of claim 10 , wherein a nanoparticle loading in the polymeric insulating material ranges from >30% to ≤90% by weight.
12 . The filtered feedthrough assembly of claim 1 , wherein the nanoparticles range in size from greater than about 100 nanometers (0.1 microns) to about 40,000 nanometers (40 microns).
13 . The filtered feedthrough assembly of claim 1 , wherein the first polymeric insulating material contacted to the dielectric substrate second end surface is a first polymeric insulating washer having opposed first and second sides, and wherein a first thermoplastic coating contacts the first side of the first polymeric insulating washer adjacent to the dielectric substrate second end surface.
14 . The filtered feedthrough assembly of claim 13 , wherein the first thermoplastic coating contacting the first side of the first polymeric insulating washer adjacent to the dielectric substrate second end surface is an insulative adhesive.
15 . The filtered feedthrough assembly of claim 1 , wherein the first terminal pin is a first active terminal pin, and wherein a first electrical connection material connects the first active terminal pin to a capacitor first metallization electrically connected to the at least one active electrode plate in the first passageway.
16 . The filtered feedthrough assembly of claim 1 ; wherein electrical connection material connecting from the external ground metallization to the oxide-resistant pocket-pad connected to the ferrule is at least one of:
a) a solder selected from, by weight percent, Pb 37.5 Sn 1 Ag 1.5 , Sn 10 Pb 88 Ag 2 , Au 82 In 18 , Au 96.8 Si 3.2 , Au 98 Si 2 , Au 87.5 Ge 12.5 , Cd 95 Ag 5 , Pb 92 Cd 8 , Pb 97.5 Ag 1.5 Sn 1 , Pb 95 Ag 5 , Pb 94.5 Ag 5.5 , Pb 97.5 Ag 2.5 , Pb 95.5 In 5 Au 2.5 , Pb 92.5 In 5 Ag 2.5 , Pb 95.5 Sn 2 Ag 2.5 , Pb 93.5 Sn 5 Ag 1.5 , Pb 90 Sn 5 Ag 5 , Pb 90 In 5 Ag 5 , Pb 92.5 Sn 5 Ag 2.5 , Pb 92 Sn 5.5 Ag 2.5 , Pb 81 In 19 , Pb 90 Sn 10 , Pb 88 Sn 10 Ag 2 , Cd 82.5 Zn 17.5 , Zn 90 Cd 10 , Zn 60 Cd 40 , Cd 60 Zn 40 , Cd 70 Zn 30 , Pb 88 Sn 12 , Pb 96 Sn 2 Ag 2 , Pb 80 Sn 18 Ag 2 , Pb 75 In 25 , Cd 78 Zn 17 Ag 5 , Pb 70 In 30 , Pb 85 Sn 15 , and combinations thereof;
b) a thermal-setting conductive adhesive selected from a conductive polymer, a conductive epoxy, a conductive silicone, or a conductive polyimide; and
c) an anisotropic conductive material selected from an Anisotropic Conductive Adhesive (ACA), an Anisotropic Conductive Film (ACE), an Anisotropic Conductive Paste (ACP), an anisotropic conductive tape, an anisotropic conductive epoxy, and combinations thereof.
17 . A filtered feedthrough assembly that is attachable to an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
a) a feedthrough, comprising;
i) An electrically conductive ferrule comprising:
A) a ferrule sidewall defining a ferrule opening, the ferrule sidewall having a ferrule height extending to a ferrule body fluid side surface spaced from a ferrule device side surface;
B) at least one recessed pocket having a depth extending from the ferrule device side surface part-way through the height of the ferrule toward the ferrule body fluid side surface; and
C) a gold pocket-pad nested in the at least one recessed pocket so that the gold pocket-pad is electrically connected to the ferrule; and
ii) an insulator hermetically sealed to the ferrule in the ferrule opening, the insulator extending to an insulator body fluid side spaced from an insulator device side, wherein, when the ferrule hermetically sealed to the insulator is attached to an opening in a housing of an AIMD, the ferrule body fluid side adjacent to the insulator body fluid side, and the ferrule device side adjacent to the insulator device side reside outside and inside the AIMD, respectively; and
iii) at least a first terminal pin hermetically sealed to the insulator in a first via hole by a first braze, wherein the first terminal pin extends outwardly beyond at least the insulator device side; and
b) a filter capacitor, comprising:
i) a dielectric substrate having a dielectric substrate peripheral surface extending to a dielectric substrate first end surface and an opposed dielectric substrate second end surface that is spaced above the ferrule device side surface, wherein the dielectric substrate supports at least one active electrode plate interleaved in a capacitive relationship with at least one ground electrode plate extending to the dielectric substrate peripheral surface, and wherein the dielectric substrate first end surface is adjacent to the insulator and the ferrule device sides; and
ii) at least a first passageway extending through the dielectric substrate to the dielectric substrate first and second end surfaces, wherein the first terminal pin extends through the first passageway and outwardly beyond the dielectric substrate second end surface, the first terminal pin being electrically connected to the at least one active electrode plate in the first passageway;
c) an external ground metallization contacting the at least one ground electrode plate at the peripheral surface;
d) an electrical connection material connecting from the external ground metallization to the gold pocket-pad Connected to the ferrule;
e) a first polymeric insulating material contacted to the dielectric substrate second end surface and the external ground metallization at the dielectric substrate peripheral surface, wherein the polymeric insulating material comprises insulating nanoparticles, wherein the first polymeric insulating material also contacts the gold pocket-pad nested in the at least one recessed pocket of the ferrule; and
f) a second polymeric insulating material as a second washer positioned between the insulator device side and the dielectric substrate first end surface, wherein the second polymeric washer has at least a washer first opening through which the first terminal pin extends, and wherein the second polymeric insulating material comprises insulating nanoparticles.
18 . The filtered feedthrough assembly of claim 17 , wherein:
a) the polymeric insulating material is selected from silicone, polyurethane, polyester, polyethylene, polypropylene, polyimide, polyamide, acrylic, polyacrylates, perfluoroalkoxy (PFA), fluorinated ethylene-propylene (FEP), polyetheretherketone (PEEK), polyamide imide (PAI), polyphenyl sulfone (PPSU), polyetherimide (PEI), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyoxymethylene (POM), polystyrene (PS), thermoplastic elastomer (TPE), polyethylene terephthalate (PET), ethylene-vinyl acetate (EVA), polyethylene-vinyl acetate (PEVA), polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), polyoxymethylene (POM) polycarbonate (PC), epoxy, rubber, acetal, polyacetal, polyformaldehyde, phenolic, polysulfide, and combinations thereof;
b) the nanoparticles are selected from Al 2 O 3 , Bao, CaO, CeO 2 , MgO, ZnO, ZrO 2 , SiO 2 , TiO 2 , Al 2 SiO 53 , BaTiO 3 , SrTiO 2 , zirconia toughened alumina (ZTA), alumina toughened zirconia (ATZ), yttrium stabilized zirconia (YSZ), yttrium-toughened zirconia (YTZP), aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), boron nitride (BN), carbon nitride (CN), and combinations thereof;
c) a nanoparticle loading in the polymeric insulating material ranges from >30% to ≤90% by weight; and
d) the nanoparticles range in size from greater than about 100 nanometers (0.1 microns) to about 40,000 nanometers (40 microns).