Process for manufacturing a leadless feedthrough for an active implantable medical device

Patent metadata

Field	Value
Publication number	US-10559409-B2
Application number	US-201916362862-A
Country	US
Kind code	B2
Filing date	Mar 25, 2019
Priority date	Jan 6, 2017
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A method for manufacturing a feedthrough dielectric body for an active implantable medical device includes the steps of first forming a ceramic reinforced metal composite (CRMC) paste by mixing platinum with a ceramic material to form a CRMC material, subjecting the CRMC material to a first sintering step to thereby form a sintered CRMC material, ball-milling or grinding the sintered CRMC material to form a powdered CRMC material; and then mixing the powdered CRMC material with a solvent to form the CRMC paste. The method further includes forming an alumina ceramic body in a green state, forming at least one via hole through the alumina ceramic body, filling the via hole with the CRMC paste, drying the ceramic body including the CRMC paste to form a first CRMC material filling the via hole, forming a second via hole through the first CRMC material, providing a metal core in the second via hole, and subjecting the ceramic body including the first CRMC material and the metal core to a second sintering step to thereby form the dielectric body. The dielectric body is then sealed in a ferrule opening to form a feedthrough.

First claim

What is claimed is:

1. A method for manufacturing a feedthrough that is configured for incorporation into an active implantable medical device (AIMD), the method comprising the steps of:
a) forming a first sintered ceramic reinforced metal composite (CRMC) paste, comprising the steps of:
i) mixing platinum with a first ceramic material to form a first CRMC material;
ii) subjecting the first CRMC material to a first sintering step to thereby form a first sintered CRMC material;
iii) ball-milling or grinding the first sintered CRMC material to form a first powdered sintered CRMC material; and
iv) mixing the first powdered sintered CRMC material with a solvent to form the first sintered CRMC paste;

b) forming a green-state ceramic body, comprising the steps of:
i) forming a ceramic body in a green state, the green-state ceramic body having a ceramic body body fluid side opposite a ceramic body device side, wherein, when the feedthrough is attached to a housing for the AIMD, the ceramic body fluid side resides outside the AIMD and the ceramic body device side resides inside the AIMD;
ii) forming at least one first via hole comprising a first via hole inner surface extending along a longitudinal axis through the green-state ceramic body to the body fluid and device sides;
iii) filling the at least one first via hole in the green-state ceramic body with the first sintered CRMC paste extending to a first sintered CRMC paste first end residing at or adjacent to the ceramic body fluid side and a first sintered CRMC paste second end residing at or adjacent to the ceramic body device side;
iv) drying the green-state ceramic body including the first sintered CRMC paste to thereby form a second CRMC material filling the at least one first via hole in the ceramic body;
v) forming a second via hole extending through the second CRMC material to the ceramic body fluid and device sides so that an inner surface of the second CRMC material is spaced closer to the longitudinal axis than the first via hole inner surface;
vi) providing a substantially pure metal core in the second via hole; and
vii) subjecting the green-state ceramic body including the second CRMC material and the substantially pure metal core to a second sintering step to thereby form a sintered ceramic body comprising the second CRMC material surrounding the substantially pure metal core; and

c) providing an electrically conductive ferrule comprising a ferrule opening; and
d) hermetically sealing the sintered ceramic body to the ferrule in the ferrule opening.

2. The method of claim 1 , further including forming the green-state ceramic body comprising the steps of:
a) sintering a second ceramic material;
b) ball-milling or grinding the sintered second ceramic material to form a second powdered sintered ceramic material; and
c) mixing the second powdered sintered ceramic material with a solvent to form the ceramic body in the green state.

3. The method of claim 1 , including mixing the first powdered sintered CRMC material with the solvent and a binder to form the first sintered CRMC paste.

4. The method of claim 1 , including providing the first sintered CRMC paste comprising platinum and, by weight or by volume, about 15% to about 80% first ceramic material.

5. The method of claim 1 , including brazing a leadwire to the substantially pure metal core after the second sintering step b), vii).

6. The method of claim 1 , including providing the first sintered CRMC paste containing about 20% to about 80% ceramic by weight or by volume.

7. The method of claim 1 , including providing the substantially pure metal core as a substantially pure metal paste containing at least 90% metal by weight or by volume, wherein after the second sintering step, the substantially pure metal core is a sintered substantially pure metal core.

8. The method of claim 1 , wherein the step of forming the ceramic body in the green state comprises stacking discrete layers of ceramic in a green state one upon another and pressing them together.

9. The method of claim 8 , wherein the pressing step is by one of the group consisting of hydro-static pressing, hot pressing, cold pressing, die pressing, and mechanical pressing.

10. The method of claim 1 , wherein between steps b), vi) and b), vii), including the step of forming at least one counterbore or countersink in the substantially pure metal core from at least one of the ceramic body fluid side and the ceramic body device side.

11. The method of claim 10 , wherein after the second sintering step b), vii), including a step of inserting a solid leadwire at least partially into the at least one counterbore or countersink followed by brazing the solid leadwire to at least one of the second CRMC material and the substantially pure metal core in the counterbore or countersink so that the solid leadwire is electrically connected to the substantially pure metal core.

12. The method of claim 1 , wherein between steps b), vi) and b), vii), including the further steps of:
a) forming at least one counterbore or countersink in the green-state ceramic body to thereby expose an inner surface of the ceramic body in the counterbore or the countersink; and
b) following the second sintering step b), vii), sputtering an adhesion metallization onto the inner surface of the sintered ceramic body in the at least one counterbore or countersink, followed by sputtering a wetting metallization onto the adhesion metallization; and
c) inserting a solid leadwire at least partially into the at least one counterbore or countersink, followed by brazing the solid leadwire to the wetting metallization in the counterbore or countersink so that the solid leadwire is electrically connected to the substantially pure metal core.

13. The method of claim 1 , including the further steps of:
a) forming at least one counterbore or countersink in the second CRMC material and in the substantially pure metal core to thereby expose an inner surface of the green-state ceramic body in the counterbore or the countersink; and
b) following the second sintering step b), vii), sputtering an adhesion metallization onto the inner surface of the sintered ceramic body in the at least one counterbore or countersink, followed by sputtering a wetting metallization onto the adhesion metallization; and
c) inserting a solid leadwire at least partially into the at least one counterbore or countersink, followed by brazing the solid leadwire to the wetting metallization in the counterbore or countersink so that the solid leadwire is electrically connected to the substantially pure metal core.

14. The method of claim 11 , including providing the solid leadwire residing on the body fluid side of the sintered ceramic body and comprising a nail head.

15. The method of claim 1 , wherein in steps b), ii) and b), v), the respective forming step is by at least one of the group consisting of drilling, punching, machining, and waterjet cutting.

16. The method of claim 1 , wherein, after drying the green-state ceramic body including the first sintered CRMC paste in step b), iv), the resulting second CRMC material is in the shape of a sleeve that surrounds the substantially pure metal core in step b), vi).

17. The method of claim 1 , wherein the substantially pure metal core is a substantially pure platinum core.

18. The method of claim 1 , including positioning a backing plate adjacent to the green-state ceramic body during the forming steps b), ii) and b), v).

19. The method of claim 18 , including providing the backing pla

Assignees

• Greatbatch Ltd

Inventors

• Seitz Keith W
• Rensel Dallas J
• Hohl Brian P
• Calamel Jonathan
• Tang Xiaohong
• Stevenson Robert A
• Frysz Christine A
• Marzano Thomas
• Woods Jason
• Brendel Richard L

Classifications

• B23K2101/36

  Electric or electronic devices · CPC title

• B23K26/32

  taking account of the properties of the material involved · CPC title

• B23K2103/14

  Titanium or alloys thereof · CPC title

• B23K1/19

  taking account of the properties of the materials to be soldered · CPC title

• B23K1/008

  Soldering within a furnace (B23K1/012 takes precedence) · CPC title