Shielded three-terminal flat-through EMI/energy dissipating filter with co-fired hermetically sealed feedthrough

Patent metadata

Field	Value
Publication number	US-9463329-B2
Application number	US-201414556239-A
Country	US
Kind code	B2
Filing date	Dec 1, 2014
Priority date	Mar 20, 2008
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A hermetic terminal assembly for an AIMD includes a shielded three-terminal flat-through EMI energy dissipating filter and a hermetically sealed feedthrough configured to be attachable to the ferrule or AIMD housing. The flat-through filter includes a first shield plate, an active electrode plate, and a second shield plate where the shield plates are electrically coupled to a metallization which in turn is coupled either to the ferrule or AIMD housing. The feedthrough includes an alumina substrate comprised of at least 96% alumina and a via hole with a substantially closed pore and substantially pure platinum fill. The platinum fill forms a tortuous and mutually conformal knitline or interface between the alumina substrate and the platinum fill, wherein the platinum fill is electrically coupled to at least one active electrode plate in non-conductive relationship to the at least one first and second shield plates.

First claim

What is claimed is:

1. A hermetic terminal assembly for an active implantable medical device (AIMD), the hermetic terminal assembly comprising:
a) a hermetically sealed feedthrough configured to be attachable to a ferrule or an AIMD housing, the feedthrough comprising:
i) an alumina substrate comprised of at least 96 percent alumina and having a thickness extending from a first substrate side to a second substrate side;
ii) a via hole disposed through the alumina substrate from the first substrate side to the second substrate side;
iii) a substantially closed pore and substantially pure platinum fill disposed within the via hole and extending between the first substrate side and the second substrate side of the alumina substrate; and
iv) 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; and

b) a shielded three-terminal flat-through EMI energy dissipating filter comprising:
i) at least one active electrode plate through which a circuit current is configured to pass between a first terminal and a second terminal;
ii) at least one first shield plate disposed on a first side of the at least one active electrode plate; and
iii) at least one second shield plate disposed on a second side of the at least one active electrode plate, where the at least one second shield plate is disposed opposite the at least one first shield plate;
iv) wherein the at least one first and second shield plates are both electrically coupled to a third terminal, where the third terminal is configured to be electrically coupled directly or indirectly to the ferrule or the AIMD housing;
v) wherein the platinum fill is electrically coupled directly or indirectly to the at least one active electrode plate and where the platinum fill is in non-conductive relationship to the at least one first and second shield plates, the ferrule and the AIMD housing.

2. The hermetic terminal assembly of claim 1 , including an insulative washer disposed between the shielded three-terminal flat-through EMI energy dissipating filter and the alumina substrate.

3. The hermetic terminal assembly of claim 2 , wherein the insulative washer comprises an adhesive insulative washer.

4. The hermetic terminal assembly of claim 1 , wherein the shielded three-terminal flat-through EMI energy dissipating filter is mounted directly onto at least a portion of the alumina substrate.

5. The hermetic terminal assembly of claim 1 , wherein the at least one active electrode plate is insulated from both the at least one first and second shield plates by a monolithic dielectric substrate.

6. The hermetic terminal assembly of claim 1 , wherein the at least one active electrode plate comprises a plurality of active electrode plates.

7. The hermetic terminal assembly of claim 6 , wherein the at least one first and second shield plates comprise a plurality of shield plates in non-conductive relationship to the plurality of active electrode plates.

8. The hermetic terminal assembly of claim 1 , including a conductive pad electrically coupled to the at least one active electrode plate and forming the second terminal, wherein the conductive pad comprises a wire bond pad disposed on an exterior surface of the shielded three-terminal flat-through EMI energy dissipating filter.

9. The hermetic terminal assembly of claim 1 , wherein the third terminal comprises a metallization, the metallization configured to be electrically coupled to the ferrule or the AIMD housing.

10. The hermetic terminal assembly of claim 1 , wherein the hermetically sealed feedthrough comprises a second via hole disposed through the alumina substrate from the first substrate side to the second substrate side, a second substantially closed pore and substantially pure platinum fill disposed within the second via hole and extending between the first substrate side and the second substrate side of the alumina substrate, and a second hermetic seal between the second platinum fill and the alumina substrate, wherein the second platinum fill forms a second tortuous and mutually conformal knitline or interface between the alumina substrate and the second platinum fill, and including at least one ground electrode plate disposed within the alumina substrate, wherein the at least one ground electrode plate is configured to electrically couple the second platinum fill to the ferrule or the AIMD housing, and where the second platinum fill is electrically coupled to the third terminal.

11. The hermetic terminal assembly of claim 1 , wherein the at least one active electrode plate at least partially comprises an inductor.

12. The hermetic terminal assembly of claim 1 , including a first monolithic chip capacitor electrically coupled between the at least one active electrode plate and the at least one first or second shield plates.

13. The hermetic terminal assembly of claim 12 , including a second monolithic chip capacitor electrically coupled in series with the at least one active electrode plate.

14. The hermetic terminal assembly of claim 1 , wherein the at least one active electrode plate is configured to form at least a component of a capacitor, a bandstop filter, an LC trap filter, an “L”, a “π”, a “T”, a “LL”, a “5 element” or an “n” element passive electronic low-pass filter, wherein the “n” element passive electronic low-pass filter is optimized for use at MRI frequencies.

15. The hermetic terminal assembly of claim 1 , wherein the at least one active electrode plate is electrically connected to a passive or active electronic component within the AIMD.

16. The hermetic terminal assembly of claim 1 , wherein the shielded three-terminal flat-through EMI energy dissipating filter is disposed on the second substrate side of the alumina substrate.

17. The hermetic terminal assembly of claim 1 , wherein the shielded three-terminal flat-through EMI energy dissipating filter is biocompatible and disposed on a first substrate side of the alumina substrate.

18. The hermetic terminal assembly of claim 1 , wherein the alumina dielectric substrate comprises at least 99 percent alumina, and wherein the platinum fill is substantially free of oxides, sintering additives and glasses, and wherein the alumina dielectric substrate is substantially free of sintering additives and glasses.

19. The hermetic terminal assembly of claim 1 , wherein the hermetic seal comprises a leak rate no greater than 1×10 −7 atmospheres cubic centimeters per second of helium.

20. The hermetic terminal assembly of claim 1 , wherein an inherent shrink rate during an elevated temperature sintering of the alumina substrate in a green state is greater than the platinum fill in the green state.

21. The hermetic terminal assembly of claim 1 , wherein the platinum fill comprises a larger cross sectional area at either a first via end exposed to the first substrate side or a second via end exposed to the second substrate side as compared to a smaller cross sectional area of the platinum fill between the first and second via ends.

22. The hermetic terminal assembly of claim 1 , including an electrically conductive cap or protrusion co-fired to the platinum fill on the first substrate side or the second substrate side.

23. The hermetic terminal assembly of claim 22 , wherein the cap or protrusion comprises a biocompatible material, platinum or titanium.

Assignees

• Greatbatch Ltd

Inventors

• Frysz Christine A
• Stevenson Robert A
• Marzano Thomas
• Tang Xiaohong
• Thiebolt William C
• Seitz Keith W

Classifications

• A61N1/3718 Primary

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• H03H2001/0042

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

• H03H2001/0085

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

• H03H7/1766

  Parallel LC in series path (H03H7/1783 takes precedence) · 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