High temperature sensor

• US 20020014107A1
• Filed: 06/29/2001
• Published: 02/07/2002
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Muller, Ralf, Moos, Ralf, Birkhofer, Thomas, Plog, Carsten, Muller, Willi, Maunz, Werner
• Granted Patent: US 6,634,212 B2
• Time in Patent Office: Days
• US Class Current: 73/31.05
• CPC Class Codes: G01N 2027/222 for analysing gases
• CPC Class Codes: G01N 27/226 Construction of measuring vessels; Electrodes therefor

Abstract

High temperature substance sensor, including

a substrate (4),

a device (6) for raising and maintaining the temperature of the sensor, and

a layer like capacitor structure (38) with structure sizes smaller than 50 μm, upon which a functional layer (18) is applied.

In accordance with the invention the layer-like capacitor structure (38) is produced by the following:

application of a complete or already pre-structured electrically conductive layer as precursor of the capacitor structure (38) using a thick layer technique,

structuring the electrically conductive layer using a photolithographic structuring process.

Claims

1. High temperature substance sensor, including

a substrate (4),

a device (6) for raising and maintaining the temperature of the sensor, and

a layer-like capacitor structure (38) with structure sizes smaller than 50 μ

m, upon which a functional layer (18) is applied,

thereby characterized, that the layer-like capacitor structure (38) is produced by the following;

application of a closed or already pre-structured electrically conductive layer as precursor of the capacitor structure (38) using a thick layer technique,

structuring the electrically conductive layer using a photolithographic structuring process.

2. High temperature substance sensor according to claim 1, thereby characterized, that the structuring of the electrically conductive layer is achieved according to the following:

application of a photosensitive resin layer upon the electrically conductive layer,

application of a photo mask, which corresponds to the capacitor structure, upon the resin layer,

exposure of the resin layer covered with the photo mask to light,

removal of the exposed areas of the resin layer,

removal of the areas of the electrically conductive layer not covered by resin.

3. High temperature substance sensor according to claim 1, thereby characterized, that the structuring of the electrically conductive layer occurs in accordance with the following steps:

application of a photosensitive resin layer upon the electrically conductive layer,

application of a photo mask, which correspond to the negative of the capacitor structure, upon the resin layer,

exposure of the photo mask covered resin layer to light,

removal of the unexposed areas of the resin layer,

removal of the areas of the electrically conductive layer not covered by resin.

4. High temperature substance sensor according to one of claims 1 through 3, thereby characterized, that the capacitor structure (38) is an interdigitated capacitor structure.

5. High temperature substance sensor according to claim 4, thereby characterized, that in the interdigitated capacitor structure, the aspect ratio of the thickness of the electrode finger (d) to the finger breadth (b) is greater than 0.10.

6. High temperature substance sensor according to one of the preceding claims, thereby characterized, that the capacitor structure (38) is comprised of a metal, in particular of gold or platinum.

7. Use of a high temperature substance sensor according to one of the preceding claims as gas sensor.

8. Use of a high temperature substance sensor according to one of the preceding claims 1 through 6 as an exhaust gas sensor in the exhaust gas of a vehicle with an internal combustion engine.