Method for fabrication of low-polarization implantable stimulation electrode

• US 20060167536A1
• Filed: 01/25/2005
• Published: 07/27/2006
• Est. Priority Date: 01/25/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Coles, James A. Jr., Nygren, Lea A., Brabec, Scott J., Rose, Randy G.
• Granted Patent: US 8,155,754 B2
• Time in Patent Office: Days
• US Class Current: 607/122
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: B24C 1/06 for producing matt surfaces, e.g. on plastic materials, on glass
• CPC Class Codes: B24C 3/322 for electrical components
• CPC Class Codes: C23C 28/32 including at least one pure metallic layer
• CPC Class Codes: Y10T 29/49204 Contact or terminal manufacturing

Abstract

A method for fabricating an implantable medical electrode includes roughening the electrode substrate, applying an adhesion layer, and depositing a valve metal oxide coating over the adhesion layer under conditions optimized to minimize electrode impedance and post-pulse polarization. The electrode substrate may be a variety of electrode metals or alloys including titanium, platinum, platinum-iridium, or niobium. The adhesion layer may be formed of titanium or zirconium. The valve metal oxide coating is a ruthenium oxide coating sputtered onto the adhesion layer under controlled target power, sputtering pressure, and sputter gas ratio setting optimized to minimize electrode impedance and post-pulse polarization.

Claims

1. A method for fabricating an implantable electrode, comprising:

roughening a surface of the electrode;

cleaning the roughened electrode surface; and

depositing a valve metal oxide coating over the roughened electrode surface.

2. The method of claim 1 wherein roughening the surface of the electrode comprises mechanical roughening of the electrode surface.

3. The method of claim 2 wherein the mechanical roughening of the electrode surface comprises grit blasting.

4. The method of claim 3 wherein the grit blasting is performed using an alumina oxide media.

5. The method of claim 1 wherein the cleaning of the roughened electrode surface comprises ultrasonic cleaning.

6. The method of claim 1 wherein the valve metal oxide includes ruthenium oxide.

7. The method of claim 1 wherein depositing the valve metal comprises sputtering the valve metal onto the cleaned and roughened electrode surface using sputtering process parameters optimized to minimize post-pulse polarization

8. The method of claim 7 wherein the sputtering process parameters, optimized to minimize post-pulse polarization, include a target power.

9. The method of claim 7 wherein the target power is about 300 Watts.

10. The method of claim 7 wherein the sputtering parameters optimized to minimize post-pulse polarization include a sputtering pressure.

11. The method of claim 7 wherein the sputtering parameters optimized to minimize post-pulse polarization include a sputtering gas ratio.

12. The method of claim 1 further comprising applying an adhesion layer to the roughened and cleaned electrode surface prior to depositing the valve metal oxide layer.

13. The method of claim 11 wherein the adhesion layer comprises a metal selected from the group of titanium and zirconium.

14. The method of claim 1 further comprising ion-etching the roughened electrode surface prior to depositing the valve metal oxide layer.

15. An implantable medical electrode, comprising:

an electrode substrate,

an adhesion layer applied to at least a portion of the electrode substrate, and

a valve metal coating deposited onto the adhesion layer under conditions controlled to minimize post-pulse polarization voltage of the electrode.

16. The electrode of claim 15 wherein the adhesion layer comprises a metal selected from the group of titanium and zirconium.

17. The electrode of claim 15 wherein the valve metal coating comprises ruthenium oxide.

18. The electrode of claim 15 wherein the valve metal coating is deposited by a sputtering process during which one or more sputtering parameters are controlled at a level optimized to minimize post-pulse polarization voltage.

19. The electrode of claim 18 wherein the sputtering parameters controlled at a level optimized to minimize post-pulse polarization voltage include one of a target power and a sputtering gas ratio.

20. The electrode of claim 18 wherein the sputtering parameters controlled at a level optimized to minimize post-pulse polarization voltage comprise a sputtering pressure.