PROCESS FOR MANUFACTURING EMI FILTERS UTILIZING COUNTER-BORED CAPACITORS TO FACILITATE SOLDER RE-FLOW

• US 20090288280A1
• Filed: 05/07/2009
• Published: 11/26/2009
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Brendel, Richard L., Stevenson, Robert A., Roberts, John, Woods, Jason, Truex, Buehl E., Lorente-Adame, Jose Luis
• Granted Patent: US 8,468,664 B2
• Time in Patent Office: Days
• US Class Current: 29/25.410
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01G 4/228 Terminals
• 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: H01G 5/00 Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
• CPC Class Codes: H01G 5/01 Details
• CPC Class Codes: H01G 5/011 Electrodes
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/435 Solid dielectric type
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

An EMI filtered terminal assembly includes at least one conductive terminal pin, a feedthrough capacitor, and a counter-bore associated with a passageway through the capacitor and the lead wire. Preferably, the feedthrough capacitor having counter-drilled holes on its top side is first bonded to a hermetic insulator. The counter-bore in the capacitor provides greater volume for the electro-mechanical attachment between the capacitor and the lead wire, permitting robotic dispensing of, for example, thermal-setting conductive adhesive.

Claims

1. A process for manufacturing an electromagnetic interference (EMI) filter for use in an active implantable medical device (AIMD), comprising the steps of:

providing a capacitor comprised of a dielectric material having active and ground electrode plates therein, and at least one through hole;

forming a rounded well in a surface of the capacitor at one end of the through hole;

inserting a pin or a lead wire at least partially into the through hole;

placing an electrically conductive material in the well, wherein the electrically conductive material comprises a liquid or semi-liquid material during at least a portion of the manufacturing process; and

utilizing the electrically conductive material to conductively couple the pin or the lead wire to one of the active or ground electrode plates.

2. The manufacturing process of claim 1, including the step of utilizing the electrically conductive material to attach the pin or the lead wire to the capacitor.

3. The manufacturing process of claim 1, wherein the electrically conductive material comprises a thermal-setting conductive adhesive, a solder, a solder preform, a solder paste, or a brazed preform.

4. The manufacturing process of claim 3, wherein the step of placing the electrically conductive material in the well includes the step of dispensing the electrically conductive material into the well by means of a hand held syringe, a robotic syringe, robotic placement of a solder preform or hand placement of a solder preform.

5. The manufacturing process of claim 1, wherein the through hole includes a conductive termination surface conductively coupled to one of the active or ground electrode plates.

6. The manufacturing of claim 5, wherein the well includes a termination surface extending contiguously from the through hole conductive termination surface.

7. The manufacturing process of claim 1, wherein the well includes a conductive termination surface.

8. The manufacturing process of claim 1, wherein the electrically conductive material conductively couples the pin or the lead wire to one of the active or ground electrode plates directly and without an intervening conductive termination surface for the electrode plates.

9. The manufacturing process of claim 8, wherein shrinkage of the dielectric material of the capacitor is greater than shrinkage of the electrode plates such that an end of the electrode plates conductively coupled to the electrically conductive material, extends inwardly from the dielectric material into the through hole.

10. The manufacturing process of claim 8, including the step of acid-etching the dielectric material adjoining the through hole prior to the step of utilizing the electrically conductive material to conductively couple the pin or the lead wire to one of the active or ground electrode plates.

11. The process of claim 1, including the step of causing at least a portion of the electrically conductive material to flow from the well into the through hole between the capacitor and the pin or the lead wire.

12. The process of claim 11, including the step of centrifuging the electrically conductive material into the through hole.

13. The process of claim 1, wherein the capacitor includes a plurality of through holes and a corresponding plurality of rounded wells that are physically and electrically isolated from one another.

14. The process of claim 1, wherein the well is formed in the surface of the capacitor when the dielectric material is in a green state.

15. The process of claim 14, including the steps of:

forming a laminate structure of the active and ground electrode plates and green dielectric material of a size to create a plurality of capacitors;

forming the through holes for each capacitor in the laminate structure;

forming a rounded well in connection with each of the through holes;

cutting or punching the capacitors from the laminate structure; and

curing the capacitors.

16. The process of claim 14, wherein the well is pressed or cut into the green ceramic material.

19. The process of claim 14, wherein the through hole is first drilled, and the well is formed by drilling a large counterbore at one of the through hole.

20. The process of claim 19, wherein the through hole and the well are formed simultaneously using a single drilling/boring operation.

23. The process of claim 1, wherein the well is formed in a semi-circular shape.

24. The process of claim 1, including the step of inserting a non-conductive material into the well and over the electrically conductive material.

25. The process of claim 1, wherein sufficient electrically conductive material is inserted into the well so that space between the capacitor and the lead wire or the pin is filled with the electrically conductive material, and the well is at least partially filled with the electrically conductive material.

26. The process of claim 1, including the step of placing a bonding washer between the capacitor and a capacitor mounting surface.

27. The process of claim 26, wherein the bonding washer has an open-ended notch configured to receive the pin or lead wire therethrough and form a path for gas to escape from the through hole as the electrically conductive material flows therein.

28. The process of claim 26, including the step of placing a plurality of bonding washers between the capacitor and the mounting surface, the bonding washers having apertures that cooperatively form a gas escape path from the through hole as electrically conductive material flows therein.

17. (canceled)

18. (canceled)

21. (canceled)

22. (canceled)

29. A process for manufacturing an electromagnetic interference (EMI) filter for use in an active implantable medical device (AIMD), comprising the steps of:

providing a capacitor comprised of a dielectric material having active and ground electrode plates therein, and at least one through hole;

forming a well in a surface of the capacitor at one end of the through hole;

inserting a pin or a lead wire at least partially into the through hole;

placing an electrically conductive material in the well, wherein the electrically conductive material comprises a liquid or semiliquid material during at least a portion of the manufacturing process; and

utilizing the electrically conductive material to conductively couple the pin or the lead wire to one of the active or ground electrode plates;

wherein the electrically conductive material conductively couples the pin or the lead wire to one of the active or ground electrode plates directly and without an intervening conductive termination surface for the electrode plates.

30. The manufacturing process of claim 29, wherein shrinkage of the dielectric material of the capacitor is greater than shrinkage of the electrode plates such that an end of the electrode plates conductively coupled to the electrically conductive material, extends inwardly from the dielectric material into the through hole.

31. The manufacturing process of claim 29, including the step of acid-etching the dielectric material adjoining the through hole prior to the step of utilizing the electrically conductive material to conductively couple the pin or the lead wire to one of the active or ground electrode plates.

32. The process of claim 29, wherein the well is formed in a semicircular shape.