Method for providing hermetic electrical feedthrough

Patent metadata

Field	Value
Publication number	US-10952332-B2
Application number	US-201916450398-A
Country	US
Kind code	B2
Filing date	Jun 24, 2019
Priority date	May 28, 2008
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

This invention provides methods for the processing of platinum metallized high temperature co-fired ceramic (HTCC) components with minimum deleterious reactions between platinum and the glass constituents of the ceramic-glass body. The process comprises co-firing a multilayer laminate green ceramic-glass body with via structures filled with a platinum powder-based material in a reducing atmosphere with a specified level of oxygen partial pressure. The oxygen partial pressure should be maintained above a minimum threshold value for a given temperature level.

First claim

What is claimed is:

1. A method of fabricating a hermetic electrical feedthrough, the method comprising:
providing a ceramic sheet, and having an upper surface and a lower surface, wherein said sheet includes silicon dioxide;
forming at least one via hole in said sheet extending from said upper surface to said lower surface;
inserting a conductive thickfilm paste, including platinum, into said via hole;
laminating said sheet with said conductive thick film paste in said via hole between an upper ceramic sheet, and a lower ceramic sheet, to form a laminated substrate wherein said via hole is encased in ceramic;
selecting an oxygen controlled environment, between 10 −38 and 10 −3 atmospheres of oxygen partial pressure, by introduction of other gasses selected from the group consisting of C0 2 /CO, C0 2 /NH 3 , C0 2 /H 2 , H 2 0/H 2 , H 2 0/NH 3 , H 2 0/CO, Nitrogen, or Argon, to balance platinum oxidation and silicon dioxide decomposition of said laminated substrate;
firing said laminated substrate in said oxygen controlled environment to a temperature to sinter said laminated substrate to form a single sintered structure and cause said conductive thick film paste in said via hole to form a metallized via, including platinum in contact with ceramic, and cause said laminated substrate to form a fired laminated substrate and a hermetic seal around said metallized via; and
removing said upper sheet material and said lower sheet material by lapping or grinding, to expose an upper and a lower surface of said metallized via.

2. The method according to claim 1 , wherein said sheet is formed of material comprised of at least 90% aluminum oxide.

3. The method according to claim 1 , wherein said fired laminated substrate after said firing and material removal steps is less than or equal to 40 mils thick.

4. The method according to claim 1 , wherein said fired laminated substrate after said firing and material removal steps is less than 15 mils thick.

5. The method according to claim 1 , wherein forming at least one via hole in said sheet comprises punching said via hole using a punch tool, etching said via hole using a solvent etching, using laser ablation or drilling said via hole.

6. The method according to claim 1 , wherein inserting a conductive material into said via hole comprises:
disposing said sheet with said via hole between a stencil layer and a vacuum base, wherein said stencil layer includes at least one through hole that is aligned above said via hole;
rolling said conductive material across said stencil layer; and
pulling said conductive material into said via hole through said hole in said stencil layer with a vacuum created by said vacuum base.

7. The method according to claim 1 , further comprising laminating said sheet with paste filled via holes between said upper sheet and said lower sheet to form said laminated substrate;
placing said sheet with paste filled via holes together with said upper ceramic sheet and said lower ceramic sheet in a heatpress; and
applying heat and pressure by said heatpress until said laminated substrate is formed.

8. The method according to claim 1 , wherein said ceramic material comprises aluminum oxide, zirconium oxide or a mixture thereof.

9. The method according to claim 1 , wherein said fired laminated substrate has a thickness of less than 20 mils after removing said upper ceramic sheet and said lower ceramic sheet material.

10. The method according to claim 1 , wherein said fired laminated substrate has a thickness of 15-20 mils after removing said upper ceramic sheet and said lower ceramic sheet material.

Assignees

• Second Sight Medical Products Inc

Inventors

• Ok Jerry
• Jiang Honggang

Classifications

• B32B2309/60

  In a particular environment · CPC title

• B32B2309/66

  Fluid other than air · CPC title

• B32B2315/02

  Ceramics · CPC title

• B32B2309/68

  Vacuum · CPC title

• B29K2995/0056

  Biocompatible, e.g. biopolymers or bioelastomers · CPC title