CO-FIRED HERMETICALLY SEALED FEEDTHROUGH WITH ALUMINA SUBSTRATE AND PLATINUM FILLED VIA FOR AN ACTIVE IMPLANTABLE MEDICAL DEVICE

• US 20140161973A1
• Filed: 02/18/2014
• Published: 06/12/2014
• Est. Priority Date: 01/16/2012
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Tang, Xiaohong, Thiebolt, William C., Frysz, Christine A., Seitz, Keith W., Stevenson, Robert A., Brendel, Richard L., Marzano, Thomas, Woods, Jason, Frustaci, Dominick J., Winn, Steven W.
• Granted Patent: US 9,492,659 B2
• Time in Patent Office: Days
• US Class Current: 427/125
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: B23K 35/3013 Au as the principal constituent
• CPC Class Codes: C22C 29/12 based on oxides
• CPC Class Codes: H01G 2/103 Sealings, e.g. for lead-in wires; Covers
• CPC Class Codes: H01G 4/005 Electrodes
• CPC Class Codes: H01G 4/12 Ceramic dielectrics H01G4/085 takes precedence
• CPC Class Codes: H01G 4/30 Stacked capacitors H01G4/33 takes precedence
• CPC Class Codes: H01G 4/35 Feed-through capacitors or anti-noise capacitors
• CPC Class Codes: H01G 4/40 Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01R 43/00 Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors of trolley lines B60M1/28
• CPC Class Codes: H02G 3/22 Installations of cables or lines through walls, floors or ceilings, e.g. into buildings
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing

Abstract

A co-fired hermetically sealed feedthrough is attachable to an active implantable medical device. The feedthrough comprises an alumina dielectric substrate comprising at least 96 or 99% alumina. A via hole is disposed through the alumina dielectric substrate from a body fluid side to a device side. A substantially closed pore, fritless and substantially pure platinum fill is disposed within the via hole forming a platinum filled via electrically conductive between the body fluid side and the device side. A hermetic seal is between the platinum fill and the alumina dielectric substrate, wherein the hermetic seal comprises a tortuous and mutually conformal interface between the alumina dielectric substrate and the platinum fill.

Claims

1. A method of manufacturing a hermetically sealed feedthrough, comprising the steps of:

a) forming a dielectric substrate comprising at least 96 percent alumina;

b) forming at least one via hole extending through the dielectric substrate;

c) filling the at least one via hole with a conductive fill, the conductive fill including a platinum powder and an inactive organic binder, solvent or plasticizer;

d) placing the dielectric substrate and conductive fill into an air filled heating chamber;

e) heating the dielectric substrate and conductive fill to a temperature of from about 400°

C. to 700°

C. and holding that temperature for a period of time that is sufficient for the inactive organic binder, solvent and plasticizer to be substantially baked out of the platinum fill;

f) heating the dielectric substrate and platinum fill to a temperature of about 1,400°

C. to about 1,900°

C. and holding that temperature for a period of time sufficient for the conductive fill to hermetically seal to the dielectric substrate forming a monolithic structure; and

g) cooling the heating chamber.

2. The method of claim 1 including forming a knitline between the platinum paste and the dielectric substrate comprising a glass that is at least about 60% silica.

3. The method of claim 1 including heating the dielectric substrate for a minimum of 4 hours.

4. The method of claim 1 including laminating a plurality of alumina sheets to form the dielectric substrate.

5. The method of claim 4 including forming a via hole through a thickness of each of the plurality of the alumina sheets and then aligning the respective via holes in registry with each other, thereby forming the dielectric substrate.

6. The method of claim 1 including pressing an alumina powder to form the dielectric substrate.

7. The method of claim 1 including laminating a plurality of alumina sheets to form the dielectric substrate.

8. The method of claim 1 including cooling the heating chamber by turning off the heating chamber and allowing the chamber to equalize to room temperature.

9. The method of claim 1 including cooling the heating chamber by at a rate of up to 5°

C./min from the hold temperature cooled down to about 1,000°

C.

10. The method of claim 9 including allowing the heating chamber to naturally equalize to room temperature starting at about 1,000°

C.

11. The method of claim 1 including cooling the heating chamber at a rate of 1°

C./min from the hold temperature to about 1,000°

C. and then allowing the heating chamber to naturally equalize to room temperature.

12. The method of claim 1 wherein a resistance of the platinum fill from a first side of the dielectric substrate to a second side thereof is no greater than about 0.5 ohms.

13. The method of claim 1 wherein a resistance of the platinum fill from a first side of the dielectric substrate to a second side thereof is no greater than about 0.3 ohms.

14. The method of claim 1 wherein a resistance of the platinum fill from a first side of the dielectric substrate to a second side thereof is no greater than about 100 milliohms.

15. The method of claim 1 wherein a resistance of the platinum fill from a first side of the dielectric substrate to a second side thereof is no greater than about 10 milliohms.

16. The method of claim 1 wherein a resistance of the platinum fill from a first side of the dielectric substrate to a second side thereof is no greater than about 2 milliohms.