Method of applying insulation for coating implantable components and other microminiature devices

• US 6,472,122 B1
• Filed: 09/09/1999
• Issued: 10/29/2002
• Est. Priority Date: 12/20/1996
• Status: Expired due to Term

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Lucisano, Joseph Y., Pendo, Shaun M., Shah, Rajiv, Schulman, Joseph H., Byers, Charles L.
• Primary Examiner(s): Baxter, Janet
• Assistant Examiner(s): Walke, Amanda C.
• Application Number:
  US09/393,438
• Time in Patent Office: 1,146 Days
• Field of Search: 430/311, 430/315, 204/192.11, 204/192.15, 623/3.1, 428/613, 428/636, 606/41, 427/2.1, 427/2.12, 427/2.24, 427/435, 427/437
• US Class Current: 430/311
• 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, zerconia, or other ceramic, less than 25 microns thick, e.g., 5-10 microns thick. The alumina layer(s) may be applied at 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 placing a sealed, protective and insulative coating on an object to be submersed in a conductive medium, said method comprising:

(a) depositing a layer of titanium on a surface of the object that is about 300 Å

thick; and

(b) depositing a layer of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide over the surface of the object that is about 5-10 microns thick.

2. The method set forth in claim 1 wherein step (b) comprises depositing, using an ion-enhanced evaporative sputtering technique, successive layers of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide over the entire surface of the object.

3. The method set forth in claim 1 wherein step (b) comprises depositing, using an ion-beam deposition (IBD) technique, successive layers of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide over selected portions of the object.

4. A method as recited in claim 1, wherein depositing a layer of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide comprises depositing, using an ion-enhanced deposition technique, successive layers of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide over at least a portion of the surface of the object.

5. A method as recited in claim 1, wherein depositing a layer of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide comprises depositing, using an ion-beam deposition (IBD) technique, successive layers of alumina, zirconia, magnesium oxide, alloys of alumina, zirconia or magnesium oxide over at least a portion of the surface of the object.

6. A method as recited in claim 1, wherein the conductive medium comprises living tissue.

7. A method of placing a sealed, protective and insulative coating on an object to be submersed in a conductive medium, said method comprising:

(a) depositing a layer of titanium on a surface of the object; and

(b) depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide over the surface of the object that is less than 25 microns thick.

8. A method as recited in claim 7, wherein deposition a layer titanium comprises depositing a layer of titanium that is about 300 Å

thick.

9. A method as recited in claim 7, wherein depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide comprises depositing a layer that is within the range of about 5 microns and about 25 microns thick.

10. A method as recited in claim 7, wherein depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide comprises depositing a layer that is within the range of about 5 microns and about 10 microns thick.

11. A method as recited in claim 7, wherein depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide comprises depositing a layer of alumina or alloys of alumina.

12. A method as recited in claim 7, wherein depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide comprises depositing, using ion-enhanced deposition technique, successive layers of alumina, magnesium oxide, alloys of alumina, or alloys of magnesium oxide over at least a portion of the surface of the object.

13. A method as recited in claim 7, wherein depositing a layer of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide comprises depositing, using an ion-beam deposition (IBD) technique, successive layers of alumina, magnesium oxide, alloys of alumina or alloys of magnesium oxide over at least a portion of the surface of the object.

14. A method as recited in claim 7, wherein the conductive medium comprises living tissue.