Insulated implantable electrical circuit

• US 20060225274A1
• Filed: 05/26/2006
• Published: 10/12/2006
• Est. Priority Date: 08/09/2002
• Status: Active Grant

• Current Assignee: Second Sight Medical Products, Inc.
• Original Assignee: Second Sight Medical Products, Inc.
• Inventors: Greenberg, Robert, Talbot, Neil Hamilton, Neysmith, Jordan Matthew, Ok, Jerry
• Granted Patent: US 9,131,863 B2
• Time in Patent Office: Days
• US Class Current: 29/846
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61N 1/0529 Electrodes for brain stimulation
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: C23C 16/01 on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H05K 1/032 consisting of one material
• CPC Class Codes: H05K 2201/0179 Thin film deposited insulating layer, e.g. inorganic layer for printed capacitor
• CPC Class Codes: H05K 2203/016 Temporary inorganic, non-metallic carrier, e.g. for processing or transferring
• CPC Class Codes: H05K 2203/0502 Patterning and lithography
• CPC Class Codes: H05K 2203/176 Removing, replacing or disconnecting component; Easily removable component thermal arrangements, e.g. to prevent overheating H05K1/0201
• CPC Class Codes: H05K 3/007 Manufacture or processing of a substrate for a printed circuit board supported by a temporary or sacrificial carrier H05K1/187, H05K3/20 and H05K3/4682 take precedence
• CPC Class Codes: H05K 3/048 using a lift-off resist pattern or a release layer pattern
• CPC Class Codes: H05K 3/06 the conductive material being removed chemically or electrolytically, e.g. by photo-etch process semi-additive methods H05K3/108
• CPC Class Codes: H05K 3/28 Applying non-metallic protective coatings H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673
• CPC Class Codes: H05K 3/4676 Single layer compositions
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

The invention is directed to an implantable insulated electrical circuit that utilizes polyparaxylylene, preferably as Parylene, a known polymer that has excellent living tissue implant characteristics, to provide for chronic implantation of conductive electrical devices, such as stimulators and sensors. The device is thin, flexible, electrically insulated, and stable after long exposure to living tissue. Layers of Parylene may be combined with layers of a polymer, such as polyimide, to yield greater design flexibility in the circuit. Multiple electrical conduction layers may be stacked in the circuit to increase packing density.

Claims

1. An insulated flexible electrical circuit suitable for implantation comprising:

a first polyparaxylylene layer;

a second polyparaxylylene that defines at least one aperture exposing an electrical conductor, and

said electrical conductor located between said first polyparaxylylene layer and said second polyparaxylylene layer.

2. The electrical circuit of claim 1, wherein said polyparaxylylene is comprised of Parylene.

3. The electrical circuit of claim 1, further comprising at least one polymer layer between said first polyparaxylylene layer and said second polyparaxylylene layer.

4. The electrical circuit of claim 3, wherein said polymer is comprised of polyimide.

5. The electrical circuit of claim 1, further comprising at least one polymer layer on said first polyparaxylylene layer or said second polyparaxylylene layer that is not located between said layers.

6. The electrical circuit of claim 5, wherein said polymer is comprised of polyimide.

7. The electrical circuit of claim 1, further comprising a layer of a polymer between said first polyparaxylylene layer and said electrical conductor.

8. The electrical circuit of claim 7, wherein said polymer is comprised of polyimide.

9. The electrical circuit of claim 1, wherein said electrical conductor is suitable for stimulating a nerve.

10. The electrical circuit of claim 1, wherein said electrical conductor is suitable for sensing a signal from a nerve.

11. The electrical circuit of claim 1, wherein said second polyparaxylylene that defines at least one aperture further defines an electrode site suitable for detecting or transmitting signals to living tissue.

12. The electrical circuit of claim 1, wherein said electrical conductor is comprised of a biocompatible material.

13. The electrical circuit of claim 12, wherein said biocompatible material is selected from at least one metal from the group of titanium, platinum, gold, or iridium.

14. The electrical circuit of claim 1, wherein said electrical conductor is at least partially coated with a biocompatible material.

15. The electrical circuit of claim 14, wherein said biocompatible material is comprised of titanium nitride.

16. A method of forming an insulated flexible electrical circuit suitable for implantation, comprising the steps of:

choosing a rigid substrate;

cleaning said rigid substrate;

depositing a first polyparaxylylene layer on said rigid substrate;

depositing an electrical conductor on said first polyparaxylylene layer;

patterning said electrical conductor to form a conductive path thereon;

depositing a second polyparaxylylene layer;

defining at least one select portion of said second polyparaxylylene layer; and

removing said at least one select portion of said second polyparaxylylene layer defining at least one aperture therein, thereby forming at least one electrode that is suitable for contacting living tissue.

17. The method of claim 16, wherein said step of choosing a rigid substrate is accomplished by choosing said substrate comprised of glass.

18. The method of claim 16, further comprising the step of enhancing said first polyparaxylylene layer for adhesion after said step of depositing a first polyparaxylylene layer.

19. The method of claim 16, further comprising the step of enhancing said electrical conductor for adhesion after said step of patterning said electrical conductor to form a conductive path.

20. The method of claim 16, further comprising the step of enhancing said first polyparaxylylene layer for adhesion before said step of depositing a second polyparaxylylene layer.

21. The method of claim 16, further comprising the step of applying silane to enhance adhesion.

22. The method of claim 16, further comprising the step of modifying by chemical means said first polyparaxylylene layer.

23. The method of claim 16, further comprising the step of roughening the polyparaxylylene surface.

24. The method of claim 16, further comprising the step of compressing thermally said first polyparaxylylene layer and said second polyparaxylylene layer to increase adhesion.

25. The method of claim 16, wherein said step of removing said at least one select portion of said second polyparaxylylene layer is accomplished by etching with reactive ions.