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

• US 10,249,415 B2
• Filed: 01/05/2018
• Issued: 04/02/2019
• Est. Priority Date: 01/06/2017
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• 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.
• Primary Examiner(s): Patel, Devang R
• Application Number:
  US15/863,194
• Publication Number:
  US 20180197661A1
• Time in Patent Office: 452 Days
• Field of Search: None
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: B22F 7/04 with one or more layers not made from powder, e.g. made from solid metal
• CPC Class Codes: B22F 7/08 with one or more parts not made from powder B22F7/062 takes precedence
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 1/008 Soldering within a furnace B23K1/012 takes precedence
• CPC Class Codes: B23K 1/19 taking account of the properties of the materials to be soldered
• CPC Class Codes: B23K 2101/36 Electric or electronic devices
• CPC Class Codes: B23K 2103/14 Titanium or alloys thereof
• CPC Class Codes: B23K 26/21 by welding
• CPC Class Codes: B23K 26/32 taking account of the properties of the material involved
• CPC Class Codes: C04B 41/0072 Heat treatment
• CPC Class Codes: C04B 41/4578 Coating or impregnating of green ceramics or unset concrete
• CPC Class Codes: C04B 41/5122 Pd or Pt
• CPC Class Codes: C04B 41/5177 characterised by the non-metallic part of the metallising composition
• CPC Class Codes: C04B 41/5194 Metallisation of multilayered ceramics, e.g. for the fabrication of multilayer ceramic capacitors
• CPC Class Codes: C04B 41/88 Metals
• CPC Class Codes: H01B 17/30 Sealing
• CPC Class Codes: H01B 19/02 Drying; Impregnating

Abstract

A method of manufacturing a feedthrough dielectric body for an active implantable medical device includes the steps of: a) forming an alumina ceramic body in a green state, or, stacking upon one another discrete layers of alumina ceramic in a green state and pressing; b) forming at least one via hole straight through the alumina ceramic body; c) filling the at least one via hole with a ceramic reinforced metal composite paste; d) drying the alumina ceramic body and the ceramic reinforced metal composite paste; e) forming a second hole straight through the ceramic reinforced metal composite paste being smaller in diameter in comparison to the at least one via hole; f) filling the second hole with a substantially pure metal paste; g) sintering the alumina ceramic body, the ceramic reinforced metal composite paste and the metal paste; and h) hermetically sealing the feedthrough dielectric body to a ferrule.

Claims

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 dielectric body, comprising the steps of;

A) forming a ceramic body in a green state, or, stacking discrete layers of ceramic in a green state one upon another and pressing them to form the ceramic body in the green state, the 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 body fluid side of the ceramic body resides outside the AIMD and the device side of the ceramic body resides inside the AIMD;

B) forming at least one first via hole comprising a first via hole inner surface extending along a longitudinal axis through the ceramic body to the body fluid and device sides;

C) providing a ceramic reinforced metal composite (CRMC) paste in the at least one first via hole, the CRMC paste comprising platinum and, by weight or by volume, about 15% to about 80% ceramic material, wherein the CRMC paste extends to a CRMC first end residing at or adjacent to the ceramic body body fluid side and to a CRMC second end residing at or adjacent to the ceramic body device side;

D) drying the ceramic body including the CRMC paste to thereby form a first CRMC material filling the at least one via hole in the ceramic body;

E) forming a second via hole extending through the first CRMC material to the ceramic body body fluid and device sides so that an inner surface of the first CRMC material is spaced toward the longitudinal axis with respect to the first via hole inner surface;

F) providing a substantially pure metal core in the second via hole; and

G) sintering the ceramic body including the first CRMC material and the substantially pure metal core to thereby form the dielectric body; and

b) providing an electrically conductive ferrule comprising a ferrule opening; and

c) hermetically sealing the dielectric body to the ferrule in the ferrule opening.

2. The method of claim 1, wherein the CRMC paste is at least partially made from a pre-sintered metal and ceramic construct that is ball milled or ground down.

3. The method of claim 1, including the step of forming the second via hole through at least a portion of the first CRMC material from either the ceramic body body fluid side or the ceramic body device side.

4. The method of claim 1, including brazing a leadwire to the substantially pure metal core after the sintering step.

5. The method of claim 1, wherein the CRMC paste contains 20% to 80% ceramic by weight or by volume.

6. The method of claim 1, wherein the substantially pure metal core is a substantially pure metal paste that contains at least 90% metal by weight or by volume.

7. The method of claim 1, wherein the substantially pure metal core is a substantially pure metal paste that contains at least 95% metal by weight or by volume.

8. The method of claim 1, wherein the substantially pure metal core is a substantially pure metal paste that contains at least 98% metal by weight or by volume.

9. The method of claim 1, wherein between steps F) and G), including the step of forming a counterbore or countersink in the substantially pure metal core from either the ceramic body body fluid side or the ceramic body device side.

10. The method of claim 9, wherein after the sintering step G), including a step of inserting a solid leadwire at least partially into the counterbore or countersink followed by brazing the solid leadwire to at least one of the sintered CRMC material and the sintered substantially pure metal core in the counterbore or countersink so that the solid leadwire is electrically connected to the sintered substantially pure metal core.

11. The method of claim 1, wherein between steps F) and G), including the further steps of:

a) forming a counterbore or countersink in the ceramic body to thereby expose an inner surface of the ceramic body in the counterbore or the countersink;

b) sputtering an adhesion metallization onto the inner surface of the ceramic body in the counterbore or countersink, followed by sputtering a wetting metallization onto the adhesion metallization; and

c) inserting a solid leadwire at least partially into 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 sintered substantially pure metal core.

12. The method of claim 11, including the further steps of:

a) forming a counterbore or countersink in the CRMC material and in the substantially pure metal core to thereby expose an inner surface of the ceramic body in the counterbore or the countersink;

b) sputtering an adhesion metallization onto the inner surface of the ceramic body in the counterbore or countersink, followed by sputtering a wetting metallization onto the adhesion metallization; and

c) inserting a solid leadwire at least partially into 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 sintered substantially pure metal core.

13. The method of claim 9, including providing the solid leadwire residing on the body fluid side of the ceramic body and comprising a nail head.

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

15. The method of claim 1, wherein in step A), the pressing step is by one of the group consisting of hydro-static pressing, hot pressing, cold pressing, die pressing, and mechanical pressing.

16. The method of claim 1, wherein, after drying the ceramic body including the CRMC paste in step D), the resulting first CRMC material is in the shape of a sleeve that surrounds the substantially pure metal core.

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 ceramic body during the forming steps B) and E).

19. The method of claim 18, including providing the backing plate comprising a backing plate hole, and aligning the backing plate hole with the at least one first via hole, and wherein the backing plate hole is larger in diameter than the at least one first via hole.

20. The method of claim 19, wherein the backing plate is a sacrificial alumina body in a green state.

21. The method of claim 1, including the additional steps of:

a) before the sintering step G), filling the second via hole with a second CRMC paste, wherein the second CRMC paste has a higher percentage of metal based on weight or by volume in comparison to the first CRMC paste;

b) drying the ceramic body including the first CRMC material and the second CRMC paste to thereby form first and second CRMC materials filling the at least one via hole in the ceramic body; and

c) forming a third via hole through the second CRMC material,

d) wherein in step F), the substantially pure metal core is provided in the third via hole.

22. The method of claim 21, including the additional steps of:

a) before the sintering step G), filling the third via hole with a third CRMC paste, wherein the third CRMC paste has a higher percentage of metal based on weight or by volume in comparison to the second CRMC paste;

b) drying the ceramic body including the first and second CRMC materials and the third CRMC paste to thereby form first, second and third CRMC materials filling the at least one'"'"'via hole in the ceramic body; and

c) forming a fourth via hole through the third CRMC material,

d) wherein in step F), the substantially pure metal core is provided in the fourth via hole.

23. The method of claim 1, including hermetically sealing the dielectric body to the ferrule using a gold braze.

24. The method of claim 1, wherein after step G), but before hermetically sealing the dielectric body to the ferrule, including the step of removing a thin layer of material from at least one of the ceramic body body fluid side and the ceramic body device side by a technique selected from the group consisting of lapping, grinding, water-cutting, jetting processes, and by grit-blasting.

25. The method of claim 1, wherein in step D), drying the ceramic body comprising the first CRMC paste is by at least one of the group consisting of waiting a period of time, heating the ceramic body at an elevated temperature, and placing the ceramic body in a vacuum.

26. The method of claim 1, including after sintering the ceramic body including the first CRMC material and the substantially pure metal core in step G) to thereby form the dielectric body, attaching a conductive leadwire to the substantially pure metal core adjacent to at least one of the ceramic body body fluid side and the ceramic body device side.

27. The method of claim 26, including attaching the conductive leadwire to the substantially pure metal core 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.

28. The method of claim 1, including providing the ferrule being configured to be attachable to an opening in a housing of an AIMD.

29. The method of claim 1, including providing the ferrule as part of a housing of the AIMD.

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

34. The method of claim 1, wherein the CRMC paste of step C) is at least partially made from a pre-sintered platinum and ceramic construct that is ball milled or ground down.

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

a) forming a dielectric body, comprising the steps of;

A) forming an alumina ceramic body in a green state, or, stacking discrete layers of alumina ceramic in a green state one upon another and pressing them to form the alumina ceramic body in the green state, the alumina ceramic body having a ceramic body first side opposite a ceramic body second side;

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

C) filling the at least one via hole with a ceramic reinforced metal composite (CRMC) paste, the CRMC paste comprising platinum and, by weight or by volume, about 15% to about 80% ceramic material, wherein the CRMC paste extends to a CRMC first end residing at or adjacent to the ceramic body first side and to a CRMC second end residing at or adjacent to the ceramic body second side;

D) drying the alumina ceramic body including the CRMC paste to thereby form a CRMC material filling the at least one via hole in the alumina ceramic body;

E) forming a second via hole extending through the CRMC material to the ceramic body first and second sides, the second via hole being smaller in diameter than the at least one via hole so that a portion of the CRMC material remains in the at least one via hole;

F) forming a counterbore or countersink in the alumina ceramic body from either the ceramic body first side or the ceramic body second side;

G) filling the second via hole and the counterbore or countersink with a substantially pure metal paste; and

H) sintering the alumina ceramic body including the CRMC material and the substantially pure metal paste to thereby form the dielectric body; and

b) providing an electrically conductive ferrule comprising a ferrule opening; and

c) hermetically sealing the dielectric body to the ferrule in the ferrule opening.

32. The method of claim 31, wherein the CRMC paste of step C) is at least partially made from a pre-sintered metal and ceramic construct that is ball milled or ground down.

33. 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 dielectric body, comprising the steps of;

A) forming an alumina ceramic body in a green state, or, stacking discrete layers of alumina ceramic in a green state one upon another and pressing them to form the alumina ceramic body in the green state, the alumina ceramic body having a ceramic body first side opposite a ceramic body second side;

B) forming at least one via hole comprising a first via hole inner surface extending along a longitudinal axis through the alumina ceramic body to the ceramic body first and second sides;

C) providing a ceramic reinforce metal composite (CRMC) paste in the at least one via hole, the CRMC paste comprising platinum and, by weight or by volume, about 15% to about 80% ceramic material, wherein the CRMC paste extends to a CRMC first end residing at or adjacent to the ceramic body first side and to a CRMC second end residing at or adjacent to the ceramic body second side;

D) drying the alumina ceramic body including the CRMC paste to thereby provide a CRMC material filling the at least one via hole in the alumina ceramic body;

E) forming a counterbore or countersink in the CRMC material from either the ceramic body first side or the ceramic body second side;

F) filling the counterbore or countersink with a substantially pure metal paste; and

G) sintering the alumina ceramic body including the CRMC material and the substantially pure metal paste to thereby form the dielectric body; and

b) providing an electrically conductive ferrule comprising a ferrule opening; and

c) hermetically sealing the dielectric body to the ferrule in the ferrule opening.

35. 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 dielectric body, 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 first via hole comprising a first via hole inner surface extending along a longitudinal axis through the ceramic body to the ceramic body first and second sides;

C) providing a ceramic reinforced metal composite (CRMC) paste in the at least one first via hole, the CRMC paste comprising platinum and, by weight or by volume, about 15% to about 80% ceramic material, wherein the CRMC paste extends to a CRMC first end residing at or adjacent to the ceramic body first side and to a CRMC second end residing at or adjacent to the ceramic body second side;

D) drying the ceramic body including the CRMC paste to thereby form a CRMC material filling the at least one first via hole in the ceramic body;

E) forming a second via hole extending through the CRMC material to the ceramic body first and second sides so that an inner surface of the CRMC material is spaced toward the longitudinal axis with respect to the first via hole inner surface;

F) providing a platinum core in the second via hole; and

G) sintering the ceramic body including the CRMC material and the platinum core to thereby form the dielectric body; and

b) providing an electrically conductive ferrule comprising a ferrule opening; and

c) hermetically sealing the dielectric body to the ferrule in the ferrule opening.