Method of manufacturing a feedthrough insulator for an active implantable medical device incorporating a post conductive paste filled pressing step

• US 10,420,949 B2
• Filed: 08/13/2018
• Issued: 09/24/2019
• Est. Priority Date: 01/16/2012
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Seitz, Keith W., Marzano, Thomas, Stevenson, Robert A., Frysz, Christine A., Rensel, Dallas J., Hohl, Brian P.
• Primary Examiner(s): Vo, Peter Dungba
• Assistant Examiner(s): Carley, Jeffrey T
• Application Number:
  US16/101,639
• Publication Number:
  US 20180361164A1
• Time in Patent Office: 407 Days
• 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 1/3754 Feedthroughs
• CPC Class Codes: B22F 2007/042 characterised by the layer forming method
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/04 by applying fluid pressure , e.g. by cold isostatic pressing [CIP]
• CPC Class Codes: B22F 3/15 Hot isostatic pressing
• CPC Class Codes: B23K 35/3013 Au as the principal constituent
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2237/122 based on refractory metals
• CPC Class Codes: C04B 2237/125 based on noble metals, e.g. silver
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/403 Refractory metals
• CPC Class Codes: C04B 2237/72 Forming laminates or joined articles comprising at least two interlayers directly next to each other
• CPC Class Codes: C04B 35/00 Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 35/645 Pressure sintering
• CPC Class Codes: C04B 37/026 consisting of metals or metal salts
• CPC Class Codes: C22C 1/0466 : Alloys based on noble metals
• 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 method of manufacturing a feedthrough dielectric body for an active implantable medical device includes the steps of forming a ceramic body in a green state, or, stacking discrete layers of ceramic in a green state upon one another and laminating together. The ceramic body has a first side opposite a second side. At least one via hole is formed straight through the ceramic body extending between the first and second sides. At least one via hole is filled with a conductive paste. The ceramic body and the conductive paste are then dried. The ceramic body and the conductive paste are isostatically pressed at above 1000 psi to remove voids and to form a closer interface for sintering. The ceramic body and the conductive paste are sintered together to form the feedthrough dielectric body. The feedthrough dielectric body is hermetically sealed to a ferrule.

Claims

1. A method for manufacturing a feedthrough dielectric body for an active implantable medical device (AIMD), the method comprising the steps of:

a) forming a ceramic body in a green state, the ceramic body having a ceramic body first side opposite a ceramic body second side;

b) forming at least one via hole extending through the ceramic body to the ceramic body first and second sides;

c) filling the at least one via hole with a conductive paste;

d) following filling step c), drying the green state ceramic body and the conductive paste to thereby form an electrically conductive material filling the at least one via hole in the green state ceramic body;

e) following drying step d), pressing the green state ceramic body and the electrically conductive material;

f) following pressing step e), sintering the green state ceramic body and the electrically conductive material to thereby form the feedthrough dielectric body comprising a sintered ceramic body having an electrically conductive path extending through the at least one via hole to or adjacent to the ceramic body first and second sides; and

g) hermetically sealing the feedthrough dielectric body to a ferrule, the ferrule configured to be installed in a housing for the AIMD.

2. The method of claim 1, including performing pressing step e) as an isostatic pressing.

3. The method of claim 1, including drying the green state ceramic body and the conductive paste at a temperature of from 400°

C. to 700°

C.

4. The method of claim 2, including performing the isostatic pressing at a pressure that is from about 1,000 psi to 50,000 psi.

5. The method of claim 2, including performing the isostatic pressing at a temperature that is equal to or greater than 55°

C.

6. The method of claim 2, including holding the isostatic pressing at pressure for at least 5 minutes.

7. The method of claim 1, including performing hermetically sealing step g) by supporting an adhesion metallization on an outer surface of the sintered ceramic body, followed by supporting a wetting metallization on the adhesion metallization, followed by forming a gold braze between the wetting metallization and the ferrule.

8. The method of claim 1, including forming the ceramic body in the green state by stacking discrete layers of ceramic in a green state one upon another and laminating them together.

9. The method of claim 7, including providing the adhesion metallization comprising titanium and the wetting metallization comprising molybdenum or niobium.

10. The method of claim 1, including providing the conductive paste containing at least 90% metal, by weight or by volume.

11. The method of claim 10, including providing the conductive paste containing at least 90% platinum, by weight or by volume.

12. The method of claim 1, including performing forming step b) by at least one technique selected from the group consisting of drilling, punching, machining, and waterjet cutting.

13. The method of claim 1, including performing pressing step e) is by at least one technique selected from the group consisting of hot pressing, cold pressing, die pressing, and mechanical pressing.

14. The method of claim 1, including performing hermetic sealing step g) using a gold braze.

15. The method of claim 1, including between steps f) and g), removing a thin layer of material from at least one of the ceramic body first and second sides by at least one technique selected from the group consisting of lapping, grinding, water-cutting, jetting processes and grit-blasting.

16. The method of claim 1, including drying the ceramic body and the conductive paste in step d) by at least one technique selected from the group consisting of waiting a period of time, heating at an elevated temperature, and placing within a vacuum.

17. The method of claim 1, including after step g), attaching a conductive leadwire to the electrically conductive path at at least one of either the ceramic body first and second sides.

18. The method of claim 17, including attaching the conductive leadwire by a technique selected from the group consisting of ultrasonic welding, thermal sonic bonding, laser welding, arc welding, gas welding, resistance welding, projection welding, butt welding, slash welding, upset welding, solid state welding, friction welding, fusion welding, inductive welding, percussion welding, and electron beam welding.

19. The method of claim 1, including providing the ferrule as a separately manufactured component configured to be attachable to an opening of a housing of the AIMD.

20. The method of claim 1, including forming the ferrule as part of the housing of the AIMD.

21. The method of claim 1, including providing the green state ceramic body comprising at least 96% percent alumina, by weight or by volume.

25. The method of claim 3, including drying the green state ceramic body and the conductive paste for at least 4 hours.

22. A method for manufacturing a feedthrough dielectric body for an active implantable medical device (AIMD), the method comprising the steps of:

a) forming a ceramic body in a green state, the ceramic body having a ceramic body first side opposite a ceramic body second side, the ceramic body comprising at least 96% percent alumina, by weight or by volume;

b) forming at least one via hole extending through the ceramic body to the ceramic body first and second sides;

c) filling the at least one via hole with a conductive paste;

d) following filling step c), drying the green state ceramic body and the conductive paste to thereby form an electrically conductive material filling the at least one via hole in the green state ceramic body;

e) following drying step d), isostatic pressing the green state ceramic body and the electrically conductive material at a pressure greater than or equal to 1,000 psi and at a temperature equal to or greater than 55°

C. for a time of at least 5 minutes;

f) following pressing step e), sintering the green state ceramic body and the electrically conductive material to thereby form the feedthrough dielectric body comprising a sintered ceramic body having an electrically conductive path extending through the at least one via hole to or adjacent to the ceramic body first and second sides;

g) applying a metallization to at least a portion of the sintered ceramic body; and

h) hermetically sealing the feedthrough dielectric body to a ferrule using a gold braze contacting the metallization and the ferrule,

i) wherein the ferrule is a separately manufactured component that is attachable to an opening of a housing of the AIMD, or wherein the ferrule is formed as a part of the housing of the AIMD.

23. The method of claim 22, wherein applying the metallization to at least a portion of the sintered ceramic body comprises sputtering an adhesion metallization onto the ceramic body, followed by sputtering a wetting metallization onto the adhesion metallization, and wherein the adhesion layer comprises titanium and the wetting layer comprises molybdenum or niobium.

24. The method of claim 23, including providing the conductive paste containing at least 90% metal, by weight or by volume.