Low impedance oxide resistant grounded capacitor for an AIMD

Patent metadata

Field	Value
Publication number	US-9427596-B2
Application number	US-201514826229-A
Country	US
Kind code	B2
Filing date	Aug 14, 2015
Priority date	Jan 16, 2013
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A hermetically sealed filtered feedthrough assembly for an AIMD includes an electrically conductive ferrule with an electrically conductive extension at least partially extending into the ferrule opening. An electrically non-conductive insulator hermetically seals the ferrule opening. An electrically conductive pathway is hermetically sealed and disposed through the insulator between a body fluid and device side. A filter capacitor is located on the device side. A first low impedance electrical coupling is between a first metallization of the filter capacitor and the pathway. A ground conductor is disposed through the filter capacitor in non-conductive relation with the at least one active and ground electrode plates, where the ground conductor is electrically coupled to the extension of the ferrule. An oxide-resistant metal addition is disposed on the device side and electrically couples the ground conductor to the second metallization of the filter capacitor.

First claim

What is claimed is:

1. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:
a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule sidewall defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;
b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;
c) a filter capacitor, comprising:
i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;
ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;
e) a conductor comprising an electrically conductive material hermetically sealed and disposed through the first insulator bore, wherein the conductor is in a non-conductive relation with the conductive ferrule and extends through the dielectric bore so that a first conductor end is adjacent to the first dielectric end and a second conductor end is adjacent to the second insulator end;
f) a first electrically conductive material coupling the conductor in the dielectric bore to the first metallization coupled to the active electrode plate;
g) a second metallization electrically contacted to the ground electrode plate at at least a portion of the outer dielectric surface; and
h) a ground conductor extending through the dielectric in a non-conductive relation with the active and ground electrode plates, wherein the ground conductor has a first ground conductor end spaced from a second ground conductor end, and wherein the second ground conductor end is electrically and physically coupled to the ferrule extension; and
i) an oxide-resistant metal addition electrically and physically coupling from the second metallization contacted to the ground electrode plate at the outer dielectric surface to a location on the ground conductor spaced from the second ground conductor end coupled to the ferrule extension.

2. The assembly of claim 1 , wherein the dielectric is disposed between where the oxide-resistant metal addition is coupled to the ground conductor and the second ground conductor end coupled to the ferrule extension.

3. The assembly of claim 2 , including an insulative sheet partially disposed between the first dielectric end and the oxide-resistant metal addition.

4. The assembly of claim 1 , wherein the oxide-resistant metal addition is coupled to the ground conductor intermediate the second insulator end and the second ground conductor end coupled to the ferrule extension.

5. The assembly of claim 4 , including an insulative sheet disposed between the second dielectric end and the insulator.

6. The assembly of claim 1 , wherein the oxide-resistant metal addition is coupled to the second metallization contacted to the ground electrode plate by a second electrically conductive material.

7. The assembly of claim 6 , wherein the second electrically conductive material comprises a plurality of connections electrically coupling the oxide-resistant metal addition to the second metallization.

8. The assembly of claim 1 , wherein the oxide-resistant metal addition is coupled to the ground conductor by a third electrically conductive material.

9. The assembly of claim 1 , wherein the oxide-resistant metal addition comprises a different material as compared to the ferrule.

10. The assembly of claim 1 , wherein the oxide-resistant metal addition comprises a noble metal.

11. The assembly of claim 1 , wherein the oxide-resistant metal addition is selected from the group consisting of gold, platinum, palladium, silver, and combinations thereof.

12. The assembly of claim 1 , wherein a grounding pathway is defined from the second metallization, through the oxide-resistant metal addition and to the ferrule extension.

13. The assembly of claim 12 , wherein a total resistance of the grounding pathway is less than 5 milliohm.

14. The assembly of claim 12 , wherein a total resistance of the grounding pathway is less than 1 milliohm.

15. The assembly of claim 12 , wherein a total inductance of the grounding pathway is less than 10 nanohenries.

16. The assembly of claim 12 , wherein a total inductance of the grounding pathway is less than 1 nanohenrie.

17. The assembly of claim 1 , wherein first conductor end is spaced from the first dielectric end and a second conductor end is spaced from the second insulator end.

18. The assembly of claim 1 , wherein the oxide-resistant metal addition is selected from the group consisting of an L-shaped pad and an L-shaped pad with cutouts.

19. The assembly of claim 1 , wherein the filter capacitor is a feedthrough capacitor.

20. The assembly of claim 1 , wherein the conductor comprises a leadwire selected from the group consisting of platinum, palladium, silver, and gold.

21. The assembly of claim 1 , wherein the first insulator end is flush with the ferrule adjacent to the second dielectric end.

22. The assembly of claim 1 , wherein the insulator and the filter capacitor are either circular or rectangular in cross-section perpendicular to their longitudinal extent.

23. A hermetically sealed filtered feedthrough assembly for an implantable medical device, the filtered feedthrough assembly comprising:
a) a ferrule of an electrically conductive material, the ferrule comprising a ferrule sidewall defining a ferrule opening, wherein the ferrule comprises a ferrule extension partially extending into the ferrule opening;
b) an insulator of electrically non-conductive material, the insulator comprising an outer insulator surface extending longitudinally from a first insulator end to a second insulator end, wherein the insulator is hermetically sealed to the conductive ferrule sidewall in the ferrule opening, and wherein the insulator has at least a first insulator bore extending there through to the first and second insulator ends;
c) a filter capacitor, comprising:
i) a dielectric comprising an outer dielectric surface extending longitudinally from a first dielectric end to a second dielectric end, wherein the second dielectric end is longitudinally disposed adjacent to the first insulator end;
ii) at least one active electrode plate supported by the dielectric in an interleaved, partially overlapping relationship with at least one ground electrode plate; and
iii) at least a first and a second dielectric bores extending through the dielectric to the first and second dielectric ends;

d) a first metallization electrically contacted to the at least one active electrode plate in the first dielectric bore;
e) a conductor comprising an electrically conductive material hermetically sealed and di

Assignees

• Greatbatch Ltd

Inventors

• Woods Jason
• Brendel Richard L
• Stevenson Robert A
• Williams Christopher Michael
• Naugler Robert
• Frysz Christine A

Classifications

• A61N1/3754 Primary

  Feedthroughs · CPC title

• H03H2001/0085

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

• H01G2/02

  Mountings · CPC title

• H03H1/00

  Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network (constructional details of electromechanical transducers H03H9/00) · CPC title

• H03H2001/0042

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