LASER BRAZE CERAMIC TO AN IMPLANTABLE MEDICAL DEVICE HOUSING

• US 20140345934A1
• Filed: 05/24/2013
• Published: 11/27/2014
• Est. Priority Date: 05/24/2013
• Status: Active Grant

• Current Assignee: Heraeus Deutschland GmbH & Co. KG (Heraeus Holding GMBH)
• Original Assignee: Heraeus Precious Metals GmbH & Co. KG (Einhorn Verwaltungsgesellschaft mbH)
• Inventors: Markham, Jacob, Hausch, Ulrich, Pavlovic, Goran
• Granted Patent: US 9,431,801 B2
• Time in Patent Office: Days
• US Class Current: 174/667
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: B23K 1/0056 soldering by means of beams, e.g. lasers, E.B.
• CPC Class Codes: H02G 1/00 Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
• CPC Class Codes: H02G 3/22 Installations of cables or lines through walls, floors or ceilings, e.g. into buildings
• CPC Class Codes: Y10T 29/49213 Metal

Abstract

One aspect is a method of coupling a feedthrough assembly to a surrounding case of an implantable medical device. An insulator having a plurality of conducting elements extending therethrough is provided. The insulator is placed with conducting elements within an opening of a case, thereby defining a narrow space between the insulator and the case. A braze preform is placed adjacent the insulator and case in the narrow space. The insulator is heated with a laser until raising the temperature of the adjacent preform above its melting point such that it fills the space between the insulator and the case.

Claims

1. A method of coupling a feedthrough assembly to a surrounding case of an implantable medical device comprising:

providing an insulator having a plurality of conducting elements extending therethrough;

placing the insulator with conducting elements within an opening of a case, thereby defining a narrow space between the insulator and the case;

placing a braze preform adjacent the insulator and case in the narrow space;

heating the insulator with a laser until raising the temperature of the adjacent preform above its melting point such that it flows and fills the space between the insulator and the case.

2. The method of claim 1 further comprising placing the braze preform on a feature that is formed in the case or in the insulator, or in their combination.

3. The method of claim 2, wherein the feature is configured with a surface configured to securely hold the braze preform while it is heated by the laser.

4. The method of claim 1, wherein raising the temperature of the adjacent preform above its melting point is characterized in that the laser is directed exclusively at the case and the insulator and not directed at the preform.

5. The method of claim 1 further comprising heating the braze preform, the insulator, and the case prior to heating the insulator with the laser.

6. The method of claim 5 further comprising heating the braze preform, the insulator, and the case prior to at least 600-800°

C. prior to heating the insulator with the laser.

7. The method of claim 5 further comprising heating the braze preform, the insulator, and the case in a container, which is vacuum-sealed, prior to heating the insulator with the laser.

8. The method of claim 7 further comprising filling the container with an inert gas while heating the braze preform, the insulator, and the case.

9. The method of claim 7, wherein heating the insulator with a laser comprises heating the insulator with a laser through a glass portion of the container while the insulator is within the container.

10. The method of claim 1, wherein heating the insulator with a laser comprises heating the insulator on a surface opposite where the braze preform is placed such that the braze preform is pulled toward the laser as it melts from the heat of the applied laser.

11. An implantable medical device comprising:

a feedthrough assembly comprising an insulator and a plurality of conducting elements extending therethrough;

a case with an opening into which the feedthrough assembly is placed defining a narrow space therebetween;

a braze material filling the narrow space, thereby hermetically sealing the feedthrough assembly to the case;

characterized in that one of the feedthrough assembly and the case comprise a feature configured to securely hold the braze and in that the implantable medical device does not include a ferrule.

12. The implantable medical device of claim 11, wherein the feature is a step in the case or feedthrough assembly defining a surface on which the braze material is securely held.

13. The implantable medical device of claim 12, wherein the feedthrough assembly comprises a top surface that is exterior to the case and the step has a surface that is parallel to the top surface of the feedthrough assembly.

14. The implantable medical device of claim 11, wherein the narrow space is no less than 10 μ

m and no more than 50 μ

m.

15. The implantable medical device of claim 11, wherein the insulator and plurality of conducting elements are hermetically sealed together without solder or braze.

16. The implantable medical device of claim 15, wherein the plurality of conducting elements comprise cermet.

17. The implantable medical device of claim 15, characterized in that the feedthrough assembly includes metallization on at least one surface to control the dimensions of the braze.

18. The implantable medical device of claim 17, wherein the metallization on the feedthrough assembly controls the braze such that it is at least 0.010 inches below the top surface of the feedthrough assembly and at least 0.010 inches above a bottom surface of the feedthrough assembly.