LTCC/HTCC HYBRID FEEDTHROUGH

• US 20110125210A1
• Filed: 11/24/2009
• Published: 05/26/2011
• Est. Priority Date: 11/24/2009
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Francis, Richard W. A., Iyer, Rajesh V.
• Application Number:
  US12/625,271
• Publication Number:
  US 20110125210A1
• Time in Patent Office: Days
• US Class Current: 607/37
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: C04B 2235/75 Products with a concentration gradient
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/346 Titania or titanates
• CPC Class Codes: C04B 2237/348 Zirconia, hafnia, zirconates or hafnates
• CPC Class Codes: C04B 2237/36 Non-oxidic
• CPC Class Codes: C04B 2237/361 Boron nitride
• CPC Class Codes: C04B 2237/365 Silicon carbide
• CPC Class Codes: C04B 2237/368 Silicon nitride
• CPC Class Codes: C04B 2237/58 Forming a gradient in composition or in properties across the laminate or the joined articles
• CPC Class Codes: C04B 2237/62 Forming laminates or joined articles comprising holes, channels or other types of openings
• CPC Class Codes: C04B 2237/68 Forming laminates or joining articles wherein at least one substrate contains at least two different parts of macro-size, e.g. one ceramic substrate layer containing an embedded conductor or electrode
• CPC Class Codes: C04B 37/001 directly with other burned ceramic articles
• CPC Class Codes: Y10T 428/24744 Longitudinal or transverse tubular cavity or cell

Abstract

The present invention is directed to a ceramic monolith for use as a feedthrough in medical devices and method of making. The monolith includes a first surface, a second surface, and a passageway extending from the first surface to the second surface. The first surface is high temperature co-fired ceramic and the second surface is low temperature co-fired ceramic, and the two ceramics are intermixed in a blended interface located between the first and second surfaces.

Claims

1. A ceramic monolith, comprising:

a) a first surface comprising a high temperature co-fired ceramic (HTCC);

b) a second surface comprising a low temperature co-fired ceramic (LTCC);

c) a passageway extending from the first surface to the second surface; and

d) a blended interface located between the first and second surfaces, the interface comprising intermixed HTCC and LTCC, wherein there is more LTCC disposed proximate to the second surface than proximate to the first and more HTCC disposed proximate to the first surface than proximate to the second surface.

2. The ceramic monolith of claim 1, wherein the LTCC and HTCC are interspersed within the monolith such that the ratio of LTCC to HTCC increases with distance from the first surface toward the second surface.

3. The ceramic monolith of claim 1, wherein the first and second surfaces are substantially parallel to one another

4. The ceramic monolith of claim 1, wherein the first and second surfaces are substantially perpendicular to one another

5. The ceramic monolith of claim 1, wherein the passageway does not extend out of the first surface.

6. The ceramic monolith of claim 1, the monolith further comprising a ceramic or metal augmenting member within the monolith.

7. An implantable medical device comprising a feedthrough, the feedthrough comprising:

a) a first surface comprising high temperature co-fired ceramic (HTCC);

b) a second surface comprising low temperature co-fired ceramic (LTCC); and

c) a blended interface located between the first and second surfaces, the interface comprising intermixed HTCC and LTCC such that there is more LTCC disposed proximate to the second surface than proximate to the first surface and more HTCC disposed proximate to the first surface than proximate to the second surface.

8. The implantable medical device of claim 7, wherein the feedthrough is an electrical feedthrough and comprises an electrical connection extending between the first surface and the second surface.

9. The implantable medical device of claim 8, further comprising one or more electrical components within the electrical feedthrough and in communication with the electrical connection.

10. The implantable medical device of claim 8, wherein the electrical feedthrough includes at least one capacitor connected to an electrical ground as a part of the electrical connection.

11. The implantable medical device of claim 8, wherein the electrical connection is adapted to serve as a conduit for transmission of electrical energy.

12. The implantable medical device of claim 8, further comprising a pattern of electrical connections in a plane between the first and second surfaces.

13. The implantable medical device of claim 7, wherein the feedthrough is a chemical feedthrough and comprises a passageway extending between the first surface and the second surface.

14. The implantable medical device of claim 13, wherein the passageway is an aperture extending from the first surface to the second surface.

15. A method of making a ceramic monolith, the method comprising:

g) firing a high temperature co-fired ceramic (HTCC) material to form a HTCC portion having a first surface and a second surface, the second surface having a porous region;

h) forming a passageway that extends from the first surface to the second surface of the HTCC portion;

i) providing an unfired low temperature co-fired ceramic (LTCC) material where the unfired LTCC has a sintering temperature, a first surface, and a second surface;

j) forming a passageway that extends from the first surface of the unfired LTCC material to the second surface of the unfired LTCC material;

k) mating the unfired LTCC and the fired HTCC portion together such that the passageway region on the second surface of the HTCC portion aligns with the passageway region on the second surface of the unfired LTCC to create a resulting unit with a passageway from the first surface of the HTCC portion to the first surface of the unfired LTCC; and

l) firing the resulting unit at a temperature higher than the sintering temperature of the unfired LTCC such that the LTCC material infiltrates the second surface of the HTCC portion and creates an LTCC/HTCC portion, and the unfired LTCC sinters into a LTCC portion.

16. The method of claim 15, the method further comprising introducing a conductor between the unfired LTCC material and the HTCC portion to aid formation of an electrically conductive connection between the first surface of the HTCC portion and the first surface of the unfired LTCC material.

17. The method of claim 15, wherein creating the porous region on the second surface of the HTCC portion is created by a method selected from the group consisting of:

compressing the unfired HTCC material to create a density gradient before firing, using different sized granules throughout the HTCC before firing, including organic compounds in the HTCC material to burn out during firing, including unfired LTCC material in the HTCC material to burn out during firing, abrading the second surface of the HTCC portion after firing, including inorganic material in the unfired HTCC to burn out during firing, plasma treating the second surface of the HTCC portion after firing, chemical etching the second surface of the HTCC portion after firing, optically ablating the second surface of the HTCC portion after firing, heat ablating the second surface of the HTCC portion after firing, and combinations thereof.

18. The method of claim 16, further comprising mating the unfired LTCC and the HTCC portion together such that the electrically conductive region on the second surface of the HTCC portion aligns with the electrically conductive region on the second surface of the unfired LTCC to create a resulting unit with an electrically conductive connection from the first surface of the HTCC portion to the first surface of the unfired LTCC.

19. The method of claim 15, further comprising mating the unfired LTCC and the HTCC portion together such that the passageway on the second surface of the HTCC portion aligns with the passageway on the second surface of the unfired LTCC to create a resulting unit with a passageway from the first surface of the HTCC portion to the first surface of the unfired LTCC.

20. The method of claim 15, wherein the step of forming a passageway that extends from the first surface to the second surface of the HTCC portion occurs before firing the HTCC material.