Alumina insulation for coating implantable components and other microminiature devices

• US 7,235,350 B2
• Filed: 10/20/2004
• Issued: 06/26/2007
• Est. Priority Date: 12/20/1996
• Status: Expired due to Fees

• Current Assignee: Alfred E. Mann Foundation For Scientific Research
• Original Assignee: Alfred E. Mann Foundation For Scientific Research
• Inventors: Shah, Rajiv, Schulman, Joseph H., Lucisano, Joseph Y., Byers, Charles L., Pendo, Shaun M.
• Primary Examiner(s): McPherson; John A.
• Assistant Examiner(s): CHACKO DAVIS, DABORAH
• Application Number:
  US10/969,758
• Publication Number:
  US 20050106366A1
• Time in Patent Office: 979 Days
• Field of Search: 430/311, 430/30, 428/209, 428/210, 428/469, 428/701, 204/192.11, 204/192.15
• US Class Current: 430/315
• CPC Class Codes: A61N 1/02 Details
• CPC Class Codes: C23C 14/042 using masks
• CPC Class Codes: G03F 7/70641 Focus
• CPC Class Codes: H01L 21/308 using masks H01L21/3063, H01L21/3065 take precedence
• CPC Class Codes: H01L 23/291 Oxides or nitrides or carbides, e.g. ceramics, glass
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: Y10T 29/49144 by metal fusion
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A protective, biocompatible coating or encapsulation material protects and insulates a component or device intended to be implanted in living tissue. The coating or encapsulation material comprises a thin layer or layers of alumina, zirconia or other ceramic, less than 25 microns thick, e.g., 5-10 microns thick. The alumina layer(s) may be applied at a relatively low temperature. Once applied, the layer provides excellent hermeticity, and prevents electrical leakage. Even though very thin, the alumina layer retains excellent insulating characteristics. In one embodiment, an alumina layer less than about 6 microns thick provides an insulative coating that exhibits less than 10 pA of leakage current over an area 75 mils by 25 mils area while soaking in a saline solution at temperatures up to 80° C. over a three month period.

Claims

1. A method of forming insulated conductive patterns on a substrate, the method comprising:

forming conductive patterns on a surface of the substrate;

forming a layer of titanium on the conductive patterns; and

forming a layer of ceramic material over the surface of the substrate including the conductive patterns that is about 5-10 microns thick.

2. The method recited in claim 1, wherein the conductive patterns are metallized traces.

3. The method recited in claim 2, wherein the metallized traces are formed by thin film deposition.

4. The method recited in claim 2, wherein the metallized traces are formed by thin film deposition and etching.

5. The method recited in claim 1, wherein the layer of titanium is about 300 angstroms thick.

6. The method recited in claim 1, wherein the ceramic material is selected from the group consisting essentially of alumina, zirconia, magnesium oxide, alloy of alumina, alloy of zirconia, and alloy of magnesium oxide.

7. The method recited in claim 1, wherein the layer of ceramic material is formed in successive layers.

8. The method recited in claim 7, wherein each of the successive layers is about 1-2 microns thick.

9. The method recited in claim 1, wherein the layer of ceramic material is formed using an ion-enhanced deposition technique.

10. The method recited in claim 1, wherein the layer of ceramic material is formed using an ion-beam deposition (IBD) technique.