Low inductance and low resistance hermetically sealed filtered feedthrough for an AIMD

Patent metadata

Field	Value
Publication number	US-10080889-B2
Application number	US-201414187295-A
Country	US
Kind code	B2
Filing date	Feb 23, 2014
Priority date	Mar 19, 2009
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A hermetically sealed filtered feedthrough includes a chip capacitor disposed on a circuit board on a device side. A first low impedance electrical connection is between a capacitor first end metallization and a conductor which is disposed through an insulator. A second low impedance electrical connection is between the capacitor second end metallization and a ferrule or housing. The second low impedance electrical connection may include an oxide-resistant electrical connection forming the hermetic seal between the insulator and the ferrule or housing and an electrical connection between and to the second end metallization and directly to the oxide-resistant electrical connection. Alternatively, the second low impedance electrical connection may include an oxide-resistant metal addition attached directly to the ferrule or housing and an electrical connection between and to the second end metallization and directly to the oxide-resistant metal addition.

First claim

What is claimed is:

1. A hermetically sealed feedthrough filter assembly for an implantable medical device, the feedthrough filter assembly comprising:
a) a ferrule comprising an electrically conductive material defining a ferrule opening, wherein the ferrule is configured to be attachable to an opening in a housing of an active implantable medical device;
b) an insulator at least partially residing in the ferrule opening where a first hermetic seal connects the insulator to the ferrule, wherein the insulator extends to spaced apart insulator first and second sides with an insulator via hole extending through the insulator to the insulator first and second sides;
c) an electronic circuit board comprising an active circuit trace and a ground circuit trace, wherein the active circuit trace extends from an active circuit trace first portion to an active circuit trace second portion, and the ground circuit trace extends from a ground circuit trace first portion to a ground circuit trace second portion, and wherein the circuit board has at least one circuit board active via hole extending therethrough;
d) a conductor extending to a conductor first portion and a conductor second portion, wherein the conductor is disposed through the insulator via hole where a second hermetic seal connects the conductor to the insulator so that the conductor is in a non-electrically conductive relation with the ferrule, and wherein the conductor first portion resides in the circuit board active via hole and the conductor second portion is electrically connectable to an implantable lead having an electrode configured for contact with body tissue;
e) a two-terminal chip capacitor comprising at least one active electrode plate interleaved within a capacitor dielectric with at least one ground electrode plate, wherein an active metallization is electrically connected to the at least one active electrode plate and a ground metallization is electrically connected to the at least one ground electrode plate of the two-terminal chip capacitor;
f) a first electrical connection electrically connecting the active metallization of the two-terminal chip capacitor to both:
A) the active circuit trace first portion; and
B) the conductor first portion residing in or adjacent to the circuit board active via hole,
C) wherein the active circuit trace second portion is electrically connectable to electronic circuits for an implantable medical device; and

g) a second electrical connection electrically connecting the ground metallization of the two-terminal chip capacitor to both:
A) the ground circuit trace first portion; and
B) the ground circuit trace second portion to the first hermetic seal contacting the ferrule.

2. The feedthrough filter assembly of claim 1 , wherein at least one of the first and second electrical connections comprise a noble metal structure.

3. The feedthrough filter assembly of claim 1 , wherein at least one of the first and second electrical connections comprise a gold braze.

4. The feedthrough filter assembly of claim 1 , wherein the conductor first portion extends into, but not completely through the circuit board active via hole.

5. The feedthrough filter assembly of claim 1 , wherein the second electrical connection comprises a solder contacting the first hermetic seal and an electrical connection material connecting the solder to the ground metallization of the two-terminal chip capacitor.

6. The feedthrough filter assembly of claim 1 , wherein a ground impedance loop extends from the conductor through the first electrical connection to the two-terminal chip capacitor and then from the two-terminal chip capacitor to the second electrical connection to the first hermetic seal contacting the ferrule.

7. The feedthrough filter assembly of claim 6 , wherein a total resistance of the ground impedance loop is greater than zero, but less than 0.5 ohms.

8. The feedthrough filter assembly of claim 6 , wherein a total inductance of the ground impedance loop is greater than zero, but less than 10 nanohenries.

9. The feedthrough filter assembly of claim 1 , wherein the two-terminal chip capacitor is selected from the group consisting of a monolithic ceramic chip capacitor (MLCC), a stacked film capacitor, a tantalum chip capacitor, an electrolytic chip capacitor, and a reverse geometry two-terminal chip capacitor.

10. The feedthrough filter assembly of claim 1 , wherein the circuit board is at least partially supported by the insulator.

11. The feedthrough filter assembly of claim 1 , wherein the conductor comprises a leadwire.

12. The feedthrough filter assembly of claim 11 , wherein the leadwire comprises platinum or gold.

13. The feedthrough filter assembly of claim 1 , wherein at least one of the insulator first and second sides is flush with a corresponding first and second side of the ferrule.

14. The feedthrough filter assembly of claim 1 , including at least one nonconductive adhesive washer or epoxy that is disposed between one of:
i) the circuit board and the ferrule;
ii) the circuit board and the insulator; and
ii) the circuit board and both the ferrule and the insulator.

15. The feedthrough filter assembly of claim 1 , wherein the insulator comprises an alumina substrate comprised of at least 96% alumina.

16. The feedthrough filter assembly of claim 1 , wherein the conductor first portion extends through the circuit board active via hole and the first electrical connection electrically couples to the conductor first portion extending outwardly from the circuit board active via hole.

17. The feedthrough filter assembly of claim 1 , wherein the second electrical connection material electrically connects the ground circuit trace second portion to the first hermetic seal contacting the ferrule.

18. The feedthrough filter assembly of claim 1 , wherein the circuit board comprises a flexible portion.

19. The feedthrough filter assembly of claim 1 , wherein at least one of the first and second electrical connections comprises a ball grid array.

20. The feedthrough filter assembly of claim 1 , wherein the two-terminal chip capacitor has a resonant frequency above 400 MHz.

21. The feedthrough filter assembly of claim 1 , wherein the two-terminal chip capacitor has a capacitance in a range from 300 picofarads to 10,000 picofarads.

22. A hermetically sealed feedthrough filter assembly for an active implantable medical device, the feedthrough filter assembly comprising:
a) a ferrule comprising an electrically conductive material defining a ferrule opening, wherein the ferrule is configured to be attachable to an opening in a housing of an active implantable medical device;
b) a noble metal structure welded to the ferrule spaced from the ferrule opening;
c) an insulator at least partially residing in the ferrule opening where a first hermetic seal connects the insulator to the ferrule, wherein the insulator extends to spaced apart insulator first and second sides with an insulator via hole extending through the insulator to the insulator first and second sides;
d) an electronic circuit board comprising a circuit board first side and a circuit board second side, wherein the circuit board second side is located adjacent to the insulator first side, and wherein the circuit board comprises an active circuit trace and a ground circuit trace, the active circuit trace extending from an active circuit trace first portion to an active circuit trace second portion, and the ground circuit trace extendi

Assignees

• Greatbatch Ltd

Inventors

• Marzano Thomas
• Stevenson Robert A
• Frysz Christine A
• Woods Jason
• Brendel Richard L

Classifications

• A61N1/375

  Constructional arrangements, e.g. casings · CPC title

• H03H2001/0085

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

• H01R13/5224

  for medical use · CPC title

• H01R13/7195

  with planar filters with openings for contacts · CPC title

• A61N1/3754 Primary

  Feedthroughs · CPC title