Low impedance oxide resistant grounded capacitor for an AIMD

Patent metadata

Field	Value
Publication number	US-9931514-B2
Application number	US-201615250210-A
Country	US
Kind code	B2
Filing date	Aug 29, 2016
Priority date	Jun 30, 2013
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A hermetically sealed filtered feedthrough assembly for an active implantable medical device includes an electrically conductive ferrule hermetically sealed by a first braze to an insulator. A conductor is hermetically sealed to and disposed through the insulator. A filter capacitor has an active electrode plate and a ground electrode plate which are disposed within and supported by a capacitor dielectric in an interleaved, partially overlapping relationship. A first passageway is disposed through the capacitor dielectric having a capacitor internal metallization which is connected to the active electrode plate. A capacitor external metallization electrically connects to the ground electrode plate. An oxide-resistant metal addition includes a conductive core with a conductive cladding of a different material. A first electrical connection is between the oxide-resistant metal addition and the capacitor external metallization. A second electrical connection is between the oxide-resistant metal addition and the ferrule.

First claim

What is claimed is:

1. A hermetically sealed filtered feedthrough assembly for an active implantable medical device, the filtered feedthrough assembly comprising:
a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule opening extending to a ferrule first end and a ferrule second end;
b) an insulator of an electrically non-conductive material, the insulator comprising an insulator outer surface extending to an insulator first end and an insulator second end, wherein the insulator is disposed at least partially within the ferrule opening where a first gold braze hermetically seals the insulator to the ferrule, and wherein an insulator passageway extends through the insulator;
c) an insulator metallization disposed at least partially on the insulator outer surface;
d) a conductor residing in the insulator passageway where a second gold braze hermetically seals the conductor to the insulator, the conductor extending to a conductor first segment and a conductor second segment, wherein at least the conductor first segment extends outwardly beyond the insulator first end;
e) a filter capacitor disposed near and/or on the insulator first end, the filter capacitor comprising:
i) a capacitor dielectric comprising a dielectric outer surface extending to a first dielectric end and a second dielectric end;
ii) at least one active electrode plate and at least one ground electrode plate disposed within and supported by the capacitor dielectric in an interleaved, partially overlapping relationship;
iii) a dielectric passageway disposed through the capacitor dielectric to the dielectric first end and the dielectric second end;
iv) a capacitor internal metallization disposed within the dielectric passageway and being conductively connected to the at least one active electrode plate and in non-conductive relation with the at least one ground electrode plate, wherein the conductor first segment extending outwardly beyond the insulator first end resides in the dielectric passageway where the conductor is conductively connected to the capacitor internal metallization and the at least one active electrode plate;
v) a capacitor external metallization disposed at least partially on the dielectric outer surface, the capacitor external metallization being conductively connected to the at least one ground electrode plate and in non-conductive relation with the at least one active electrode plate;

f) an oxide-resistant metal addition, comprising:
i) a conductive core;
ii) a conductive cladding disposed on the conductive core, wherein the conductive core and the conductive cladding are different materials;

g) a first conductive connection between the oxide-resistant metal addition and the capacitor external metallization; and
h) a second conductive connection between the oxide-resistant metal addition and the ferrule.

2. The feedthrough filter assembly of claim 1 , wherein the first conductive connection is selected from the group consisting of a solder, a solder BGA, a solder paste, an epoxy, and a polyimide.

3. The feedthrough filter assembly of claim 2 , wherein the second conductive connection comprises a laser weld.

4. The feedthrough filter assembly of claim 2 , wherein the second conductive connection comprises a third braze.

5. The feedthrough filter assembly of claim 4 , wherein the third braze comprising a lower temperature braze material than the first and second gold brazes.

6. The feedthrough filter assembly of claim 5 , wherein the third braze is selected from the group consisting of a low temperature gold alloy, a nano-gold preform, and a fine gold wire with small grain size.

7. The feedthrough filter assembly of claim 5 , wherein the first gold braze is disposed at or near the ferrule first end.

8. The feedthrough filter assembly of claim 7 , wherein the first gold braze is disposed at or near the ferrule second end.

9. The feedthrough filter assembly of claim 8 , wherein the first gold braze hermetically sealing the insulator to the ferrule also forms the second conductive connection between the oxide-resistant metal addition and the ferrule.

10. The feedthrough filter assembly of claim 1 , wherein the conductive core of the oxide-resistant metal addition is selected from the group consisting of stainless steel, MP35N, and niobium.

11. The feedthrough filter assembly of claim 10 , wherein the conductive core of the oxide-resistant metal addition is selected from the group consisting of a solid material, a hollow tube, a plurality of twisted fibers, a plurality of braided fibers, and a plurality of woven fibers.

12. The feedthrough filter assembly of claim 10 , wherein the conductive cladding of the oxide-resistant metal addition is selected from the group consisting of gold, palladium and platinum.

13. The feedthrough filter assembly of claim 12 , wherein the conductive cladding of the oxide-resistant metal addition is characterized as having been contacted to the conductive core by a process selected from the group consisting of plating, electroplating, as a drawn filled tubing, as a vapor deposition, as a chemical deposition, and as an overcoating.

14. The feedthrough filter assembly of claim 1 , wherein the oxide-resistant metal addition comprises a plurality of oxide-resistant metal additions.

15. The feedthrough filter assembly of claim 1 , wherein the first conductive connection comprises a plurality of first conductive connections.

16. The feedthrough filter assembly of claim 1 , wherein the second conductive connection comprises a plurality of second conductive connections.

17. The feedthrough filter assembly of claim 1 , wherein the first conductive connection is spaced from the second conductive connection along a length of the oxide-resistant metal addition.

18. The feedthrough filter assembly of claim 1 , wherein the capacitor external metallization comprises an adhesion metallization and a wetting metallization, and wherein the adhesion metallization is disposed at least partially on the insulator outer surface and the wetting metallization is disposed on the adhesion metallization.

19. The feedthrough filter assembly of claim 1 , wherein an insulative washer is disposed between the insulator and the filter capacitor.

20. The feedthrough filter assembly of claim 1 , wherein the ferrule is configured to be attachable to an opening in a housing of an active implantable medical device by a laser weld or braze.

21. The feedthrough filter assembly of claim 1 , wherein the ferrule is a continuous part of an active implantable medical device housing.

22. The feedthrough filter assembly of claim 1 , wherein the ferrule first end and the insulator first end are associated with a device side and the ferrule second end and the insulator second end are associated with a body fluid side of the assembly.

23. The feedthrough filter assembly of claim 1 , wherein the second conductive connection comprises a portion of the cladding and the core of the oxide-resistant metal addition.

24. A hermetically sealed filtered feedthrough assembly for an active implantable medical device, the filtered feedthrough assembly comprising:
a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule opening extending to a ferrule first end and a ferrule second end, wherein the ferrule is configured to be attachable to an opening in a housing of an active implantable medical device;
b) an insulator of an e

Assignees

• Greatbatch Ltd

Inventors

• Frysz Christine A
• Stevenson Robert A
• Woods Jason

Classifications

• H03H2001/0085

  Multilayer, e.g. LTCC, HTCC, green sheets · CPC title

• A61N1/3754 Primary

  Feedthroughs · CPC title

• H01G4/228

  Terminals · CPC title

• H03H2001/0042

  Wound, ring or feed-through type capacitor · CPC title

• H01G4/35

  Feed-through capacitors or anti-noise capacitors · CPC title