Implantable hermetic feedthrough

• US 8,386,047 B2
• Filed: 07/15/2010
• Issued: 02/26/2013
• Est. Priority Date: 07/15/2010
• Status: Active Grant

• Current Assignee: Advanced Bionics LLC (Sonova Holding AG)
• Original Assignee: Advanced Bionics (Sonova Holding AG)
• Inventors: Koester, Kurt J.
• Primary Examiner(s): Manuel, George
• Assistant Examiner(s): Wieland, Robert N
• Application Number:
  US12/836,899
• Publication Number:
  US 20120016444A1
• Time in Patent Office: 957 Days
• Field of Search: 607/57, 607/36, 607/37, 174/152.GM, 298/31, 340/10.1
• US Class Current: 607/57
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01R 13/5224 for medical use
• CPC Class Codes: Y10T 29/49171 with encapsulating

Abstract

An implantable hermetic system includes a hermetic case and a hermetic feedthrough sealed into an aperture in the case. The hermetic feedthrough includes vias which form electrically conductive paths through the hermetic feedthrough. A header that includes integral interconnection contacts is attached to the case. The vias are electrically joined to the interconnection contacts.

Claims

1. An implantable hermetic system comprising:

a hermetic case;

a hermetic feedthrough sealed into an aperture in the case, the hermetic feedthrough comprising ribbon vias which form electrically conductive paths through a ceramic body, in which the ribbon vias extend out of both sides of the ceramic body; and

a header comprising integral interconnection contacts, the header being attached to the case;

in which the ribbon vias are directly attached to the interconnection contacts.

2. The system of claim 1, further comprising external wires connected to an external device;

the external wires also being bonded to the interconnection contacts such that an electrical connection exists between the external wires and the ribbon vias.

3. The system of claim 1, further comprising an encapsulant which fills a cavity in the header and surrounds at least a portion of the ribbon vias.

4. The system of claim 3, in which the header and encapsulant are formed from polymeric materials.

5. The system of claim 4, in which the header is an insert molded polymer header.

6. The system of claim 1, in which the header is machined from a monolithic piece of bio-compatible material.

7. The system of claim 1, in which the interconnection contacts have substantially the same number and spacing as the ribbon vias.

8. The system of claim 1, in which the header comprises a cavity, the interconnection contacts being disposed in a wall of the cavity with at least one surface of each interconnection contact being exposed.

9. The system of claim 8, in which the header further comprises an aperture in a perimeter wall of the cavity, the ribbon vias entering the cavity through the aperture and being joined to the exposed surface of the interconnection contacts disposed in the wall of the cavity.

10. The system of claim 9, further comprising external wires exiting a cable and entering the cavity and fanning out to be joined with the interconnection contacts.

11. The system of claim 8, in which the cavity is a fan shaped cavity.

12. The system of claim 1, further comprising a first interface feature in the case, the header having a second complementary interface feature, the first interface feature and second complementary interface feature being coupled to mechanically join the case and the header.

13. The system of claim 1, in which attachment between the header and the case comprises an insert molded attachment.

14. The system of claim 1, in which attachment between the header and the case comprises an adhesive attachment.

15. The system of claim 1, in which the header and the integral interconnection contacts are formed from a monolithic piece of titanium, in which portions of titanium forming the integral interconnection contacts are electrically isolated by a dielectric from portions of the titanium that form the header.

16. The system of claim 15, in which the dielectric comprises titanium dioxide.

17. The system of claim 15, in which the hermetic case comprises titanium, in which the header is joined to the case using laser welding.

18. The system of claim 1, in which the integral interconnection contacts pass through a wall of the header and comprise a first exposed surface on a first side of the wall and a second exposed surface on a second side of the wall, in which a ribbon via is directly attached to the first exposed surface and a conductor to an external device is connected to the second exposed surface.

19. An implantable hermetic feedthrough comprising ribbon vias extending through a ceramic body, the hermetic feedthrough, being sealed into an aperture in a hermetic case, wherein the ribbon vias comprise a platinum foil coated with niobium such at when the ceramic body and plurality of ribbon vias are heated above a eutectic point, interfaces between the plurality of ribbon vias and the ceramic body are sealed using partially transient liquid phase bonding such that voids surrounding the plurality of ribbon vias are filled by a solid solution of platinum and niobium.

20. The feedthrough of claim 19, in which the ribbon vias are mechanically attached to interconnection contacts in a header, the header being attached to the hermetic case.

21. A method for forming an attachment to an implantable hermetic feedthrough with ribbon vias comprises:

forming a hermetic feedthrough with ribbon vias;

joining the hermetic feedthrough into an aperture in a case;

forming a header with embedded interconnection contacts in a wall of the header;

joining the header directly to the case;

connecting a first end of the ribbon vias to the interconnection contacts;

connecting wires from an external device to interconnection contacts; and

encapsulating the ribbon vias and external wires.

22. An implantable medical device comprising:

a titanium case having an aperture in a radial wall;

a hermetic electrical feedthrough brazed into the aperture in the radial wall, the hermetic electrical feedthrough comprising;

a ceramic body;

a plurality of ribbon vias extending through the ceramic body, the plurality of ribbon vias comprising a micromachined platinum foil having a thickness of less than 50 microns and coated with niobium such that when the ceramic body and plurality of ribbon vias are heated above a eutectic point, interfaces between the plurality of ribbon vias and the ceramic body are sealed using partially transient liquid phase bonding such that voids surrounding the plurality of ribbon vias are filled by a solid solution of platinum and niobium;

a header attached to the titanium case and encircling the hermetic feedthrough, the hermetic feedthrough having a fan shaped cavity and having integral interconnection contacts on the interior of the fan shape cavity, in which the ribbon vias are mechanically and electrically attached to the interconnection contacts;

external wires passing through the fan shaped cavity and making electrical contact with the plurality of ribbon vias; and

an encapsulant filling the fan shaped cavity and surrounding at least a portion of each ribbon via and each external wire.

23. An implantable hermetic feedthrough comprising ribbon vias extending out of a ceramic body, the hermetic feedthrough being sealed into an aperture in a hermetic case, in which the ribbon vias comprise a micromachined platinum foil having a thickness of less than 50 microns and coated with niobium such that when the ceramic body and plurality of ribbon vias are heated above a eutectic point, interfaces between the plurality of ribbon vias and the ceramic body are sealed using partially transient liquid phase bonding such that voids surrounding the plurality of ribbon vias are filled by a solid solution of platinum and niobium, and the center portions of the ribbon vias comprise tower amounts of niobium than the solid solution filling the voids.

24. A method for forming an attachment to an implantable hermetic feedthrough with ribbon vias comprises:

forming a hermetic feedthrough with ribbon vias by;

micromachining a platinum foil to form a number of ribbons connected by tethers on both ends;

depositing a coating of niobium on the foil;

sandwiching the foil between two ceramic bodies;

heating the two ceramic bodies and platinum foil to a first temperature to form a diffusion zone between the coating of niobium and the platinum foil such that at least a portion of the diffusion zone comprises a eutectic composition of platinum and niobium and the two ceramic bodies are joined into a monolithic ceramic body;

heating the ceramic bodies and platinum foil to a second higher temperature such that the eutectic composition of platinum and niobium liquefies and flows into voids surrounding the ribbon vias, in which at least a portion of the platinum foil embedded in the monolithic ceramic body remains solid during liquefaction of the eutectic composition;

maintaining the second temperature such that diffusion of niobium into the solid platinum portion of the ribbon vias creates a hypereutectic composition of platinum and niobium within the voids surrounding the ribbon vias, the hypereutectic composition solidifying in the voids surrounding the ribbon vias; and

cutting the tethers to form a plurality of electrically separate ribbon vias which pass through the ceramic body and extend out of both sides of the monolithic ceramic body;

joining the hermetic feedthrough into an aperture in a case;

forming a header with embedded interconnection contacts;

joining the header with the case;

connecting a first end of the ribbon vias to the interconnection contacts;

connecting wires from an external device to interconnection contacts; and

encapsulating the ribbon vias and external wires.