Method of making feedthrough assemblies having hermetic seals between electrical feedthrough elements and ceramic carriers therefor

• US 5,046,242 A
• Filed: 05/11/1989
• Issued: 09/10/1991
• Est. Priority Date: 07/27/1982
• Status: Expired due to Term

• Current Assignee: Commonwealth of Australia
• Original Assignee: Commonwealth of Australia
• Inventors: Kuzma, Janusz
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US07/350,574
• Time in Patent Office: 852 Days
• Field of Search: 174/50.52, 174/50.61, 174/152 GM, 228/120, 228/121, 228/122, 228/123.2, 228/123.4, 228/124, 228/188, 228/193, 228/196, 228/198, 228/903, 165/165, 29/839, 29/840, 29/843, 29/844, 29/851, 29/860, 29/878-879, 29/883-884, 445/23
• US Class Current: 29/878
• CPC Class Codes: A61N 1/3754 Feedthroughs
• CPC Class Codes: H01B 17/305 by embedding in glass or ceramic material
• CPC Class Codes: H04R 25/606 acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window
• CPC Class Codes: Y10S 228/903 Metal to nonmetal
• CPC Class Codes: Y10S 439/909 Medical use or attached to human body
• CPC Class Codes: Y10T 29/49211 of fused material
• CPC Class Codes: Y10T 29/4922 with molding of insulation
• CPC Class Codes: Y10T 29/49222 forming array of contacts or terminals

Abstract

A cochlear prosthetic package having a cup-shaped titanium case with a ceramic plate; a plurality of hermetically-sealed feedthroughs are formed in the plate by sintering the plate with hollow metallic tubes located in plate holes and then sealing at least one end of each tube. An electrode cable connector is provided which allows removal and replacement of a case even in the presence of body fluids. A telemetry coil is contained in a metallic tube which extends out of the case; the coil-containing tube has its two ends hermetically-sealed to the case by ceramic insulating bushings.

Claims

1. A method of making a feedthrough assembly having an hermetic seal between an electrical feedthrough element and a ceramic carrier therefor, comprising the steps of:

(a) forming a hole in an unsintered ceramic carrier,

(b) placing a 2-ended hollow tube of platinum, constituting said feedthrough element, axially into said hole, with a snug fit between said tube and said hole in said ceramic carrier, prior to the sintering of said ceramic carrier,

(c) subjecting said ceramic carrier with said tube therein to a temperature of about 85-90% of the melting point of the platinum for sintering said ceramic carrier and causing the latter to shrink during the sintering and exert pressure against the exterior of said tube, thereby to develop a reaction bond between the platinum of said tube and the ceramic of said carrier around the entire circumference of said tube and to create a resultant hermetic seal between said tube and said ceramic carrier, and

(d) hermetically sealing at least one end of said tube.

2. A method in accordance with claim 1, wherein a face of said ceramic carrier is flat and only one end of said tube is sealed, further including the step of:

(e) conically shaping an end of said tube which is opposite said one sealed end and is disposed at said face of said ceramic carrier and said hole such that said opposite end of said tube does not extend past said face of said ceramic carrier.

3. A method of making an assembly of a metallic tube and a ceramic carrier having an hermetic seal between the ceramic carrier and the tube, comprising the steps of:

(a) forming a hole in an unsintered ceramic carrier,

(b) placing a hollow tube of a platinum material axially and with a snug fit into said hole prior to the sintering of said ceramic carrier, and

(c) sintering said ceramic carrier at a temperature of about 85-90% of the melting point of said platinum material while said tube is located in said hole, thereby to cause said ceramic carrier to shrink against the exterior of said tube and an hermetic seal to be developed around said tube between the same and said ceramic carrier.

4. A method of making an hermetically sealed feedthrough assembly including a tubular piece of a platinum material and a ceramic carrier therefor, comprising the steps of:

(a) forming a hole in an unsintered ceramic carrier,

(b) placing a tubular piece of a platinum material axially and with a snug fit into said hole prior to the sintering of said ceramic carrier, with said tubular piece being hollow in the vicinity of said hole, and

(c) sintering said ceramic carrier at a temperature of about 85-90% of the melting point of said platinum material while said tubular piece is located in said hole, thereby to cause said ceramic carrier to shrink against the exterior of said tubular piece such that an hermetic seal between said tubular piece and said ceramic carrier, due to a reaction bond between the platinum material of said tubular piece and the ceramic of said carrier, is developed circumferentially around said tubular piece.

5. A method of making an assembly including a plurality of feedthroughs mounted in a ceramic plate and hermetically sealed thereto, comprising the steps of:

(a) forming a plurality of holes in an unsintered ceramic plate,

(b) placing a plurality of 2-ended tubular pieces of a platinum material axially and with a snug fit into said holes, respectively, prior to the sintering of said ceramic plate, with each tubular piece being hollow in the vicinity of its respective hole, and

(c) sintering said ceramic plate at a temperature of about 85-90% of the melting point of said platinum material while said tubular pieces are mounted in said holes of said ceramic plate to cause said ceramic plate to shrink against the exteriors of said tubular pieces such that hermetic seals between said ceramic plate and said tubular pieces, due to a reaction bond between the platinum material of said tubular pieces and the ceramic of said plate, are developed circumferentially around each of said tubular pieces.

6. A method in accordance with claim 5, further including the step of:

(d) sealing at least one end of each of said tubular pieces.

7. A method in accordance with claim 6, wherein a face of said ceramic plate is flat and only one end of each tubular piece is sealed, further including the step of:

(e) conically shaping an end of each of said tubular pieces which is opposite said one sealed end thereof and is disposed at said face of said ceramic plate and the associated one of said holes such that said opposite end of each tubular piece does not extend past said face of said ceramic plate.