Durable platinum/polyimide sensing structures

• US 5,780,173 A
• Filed: 09/04/1996
• Issued: 07/14/1998
• Est. Priority Date: 09/06/1995
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Harrington, Charles Robert, Sultan, Michel Farid, Troxell, John Richard, Harrington, Marie Irene
• Primary Examiner(s): LAM, CATHY FONG FONG
• Application Number:
  US08/706,756
• Time in Patent Office: 678 Days
• Field of Search: 428/670, 428/662, 428/432, 428/661, 428/606, 428/926, 257/769, 205/170, 205/183, 205/212, 205/917
• US Class Current: 428/661
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 1/6845 Micromachined devices
• CPC Class Codes: G01F 1/692 Thin-film arrangements
• CPC Class Codes: Y10S 205/917 Treatment of workpiece between coating steps
• CPC Class Codes: Y10S 428/926 Thickness of individual layer specified
• CPC Class Codes: Y10T 428/12431 Foil or filament smaller than 6 mils
• CPC Class Codes: Y10T 428/12812 Diverse refractory group metal-base components: alternative to or next to each other
• CPC Class Codes: Y10T 428/12819 Group VB metal-base component
• CPC Class Codes: Y10T 428/12875 Platinum group metal-base component

Abstract

The durability and reliability of a polymer layer/metal layer sensor structure is improved by the incorporation of a metal oxide, e.g., tantalum oxide (Ta₂ O₅), layer between the polymer, e.g., polyimide, and the metal, e.g., platinum. sensor element.

Claims

1. A thin film structure comprising a supported, thermally insulative polyimide layer, a layer of a metal oxide selected from the group consisting of aluminum oxide, chromium oxide and tantalum oxide and deposited on said polyimide layer and at least one metal strip on said metal oxide layer, said metal strip being composed of a metal selected from the group consisting of chromium, iron, nickel, palladium and platinum, the metal oxide layer being coextensive in area with the overlying metal strip so as to provide a chemical stabilization barrier between said polyimide layer and said metal.

4. A thin film structure as recited in claim 1 additionally comprising a said metal oxide layer(s) overlying said metal strip(s) and coextensive therewith.

7. A thin film structure as recited in claim 4 additionally comprising a said polymer layer overlying said metal oxide layer(s).

2. In a thin film structure comprising an insulative polyimide layer and one or more overlying patterned electrically conductive platinum strips, the improvement comprising a tantalum oxide layer interposed between said polyimide layer and said platinum strip(s) to serve as a barrier to platinum catalyzed thermal degradation of said polyimide layer.

5. A thin film structure as recited in claim 2 additionally comprising a tantalum oxide layer(s) overlying said platinum strip(s) and coextensive therewith.

8. A thin film structure as recited in claim 5 additionally comprising a polyimide layer overlying said tantalum oxide layer(s).

10. A thin film device as recited in claim 2 in which the platinum metal was applied to said tantalum oxide layer/polyimide layer that was maintained at a temperature above 250°

C. during application of said platinum.

11. A thin film device as recited in claim 2 in which the tantalum oxide layer consists essentially of Ta₂ O₅.

3. A thin film sensing device comprising a supported thermally insulative polyimide layer, a tantalum oxide layer overlying said polyimide layer and, electrically conductive platinum metallization elements overlying said tantalum oxide layer, said tantalum oxide layer being at least coextensive in area with said platinum elements so as to provide a barrier to platinum catalyzed thermal degradation of said polyimide layer and electrical insulation between said platinum elements.

6. A thin film device as recited in claim 3 additionally comprising a tantalum oxide layer(s) overlying said platinum element(s) and coextensive therewith.

9. A thin film device as recited in claim 6 additionally comprising a polyimide layer overlying said tantalum oxide layer(s).

12. A thin film sensing device as recited in claim 3 in which the platinum metallization was formed on a tantalum oxide layer/polyimide layer that was maintained at a temperature above 250°

C. during application of said platinum.

13. A thin film sensing device as recited in claim 3 in which the tantalum oxide layer consists essentially of Ta₂ O₅.