Apparatus and method for microfabricated multi-dimensional sensors and sensing systems

• US 7,911,010 B2
• Filed: 07/17/2007
• Issued: 03/22/2011
• Est. Priority Date: 07/17/2006
• Status: Active Grant

• Current Assignee: Sensirion AG (Sensirion Holding AG)
• Original Assignee: KWJ Engineering, Inc. (Interlink Electronics Incorporated)
• Inventors: Stetter, Joseph R.
• Primary Examiner(s): Nguyen; Cuong Q
• Application Number:
  US11/879,462
• Publication Number:
  US 20080054382A1
• Time in Patent Office: 1,344 Days
• Field of Search: 257415-419, 257/E29.105
• US Class Current: 257/415
• CPC Class Codes: B81B 2201/0214 Biosensors; Chemical sensors
• CPC Class Codes: B81B 2201/0278 Temperature sensors
• CPC Class Codes: B81B 2201/0292 Sensors not provided for in B81B2201/0207 - B81B2201/0285
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 3/0059 Constitution or structural means for controlling the movement not provided for in groups B81B3/0037 - B81B3/0056

Abstract

A universal microelectromechanical MEMS nano-sensor platform having a substrate and conductive layer deposited in a pattern on the surface to make several devices at the same time, a patterned insulation layer, wherein the insulation layer is configured to expose one or more portions of the conductive layer, and one or more functionalization layers deposited on the exposed portions of the conductive layer. The functionalization layers are adapted to provide one or more transducer sensor classes selected from the group consisting of: radiant, electrochemical, electronic, mechanical, magnetic, and thermal sensors for chemical and physical variables.

Claims

1. A universal microelectromechanical nano-sensor platform comprising;

a substrate including a surface with a first insulating surface layer, wherein the first insulating surface layer is an integral part of the substrate or disposed on the surface of the substrate;

a microstructure first conductive layer deposited in one or more patterns on the surface to make more than one device or electrode;

a second insulation layer, wherein the second insulation layer is configured such that it covers at least some portion of the first conductive layer'"'"'s one or more patterns and;

a second conductive layer deposited in one or more patterns on the second insulation layer to form devices or electrodes, wherein the devices can be utilized for sensing, and one or more functionalization layers deposited on at least some portion of the one or more patterns of the second conductive layer, wherein the functionalization layers are adapted to provide one or more transducer sensor classes selected from the group consisting of;

radiant, electrochemical, electronic;

mechanical, magnetic and/or thermal devices.

2. The nano-sensor platform of claim 1, wherein the substrate is a silicon wafer and wherein the first insulating layer comprises a layer of SiO2 on the substrate.

3. The nano-sensor platform of claim 1, wherein the second conductive layer is positioned on top of the second insulation layer and over the first conductive layer so as to form one or more devices from the coupling of the layers of the structure in a measuring circuit.

4. The nano-sensor platform of claim 1, wherein the first and second conductive layers comprise conductive materials, wherein conductive materials include polysilicon, metals and alloys, and wherein the metals comprise Pt, Pd, Al, Au, Ti, Mo and further wherein the alloys include TiW and PdNi.

5. The nano-sensor platform of claim 1, wherein the devices in the first and/or the second conductive layers include electrodes, heaters and/or temperature sensors.

6. The nano-sensor platform of claim 1, wherein the second insulation layer is chosen from dielectric materials including SiO2, Si3N4, silicon oxinitride, Al2O3, polymer(s) or other suitable insulator.

7. The nano-sensor platform of claim 1, wherein the second conductive layer is patterned in multiple lock and key electrode configurations and/or a configuration with multiple electrode dimensions and multiple gap configurations.

8. The nano-sensor platform of claim 1, wherein the second conductive layer is patterned over the first conductive layer to form a capacitive couple, wherein the second conductive layer and the first conductive layer are separated by an insulation layer.

9. The nano-sensor platform of claim 8, wherein the second conductive layer pattern electrode is functionalized with a layer that can form a device such as a transistor or diode device.

10. The nano-sensor platform of claim 1, wherein the one or more functionalization layers comprise polymers, polymer composites, nanostructures, or other gas sensing materials like In₂O₂ or flame spray pyrolysis coatings of nanostructures for ozone sensing.

11. The nano-sensor platform of claim 1, wherein the second conductive layer comprises leads to one or more bonding pads and wherein such leads are covered with an encapsulation layer.

12. The nano-sensor platform of claim 1, wherein the one or more functionalization layers comprise Pt, Pd, Pd/Ni, PdAg, or other suitable layer for hydrogen sensors.

13. The nano-sensor platform of claim 1, wherein the one or more functionalization layers comprise a thermoelectric material comprising catalytic and noncatalytic portions for gas sensing.

14. The nano-sensor platform of claim 1, wherein the substrate is configured to thermally isolate the devices to allow temperature controlled operation at low power.

15. The nano-sensor platform of claim 11, wherein the encapsulation layer comprises Teflon, silicone, polyethylene, or polypropylene.

16. A chip sensor, comprising:

2 or more of the nano-sensor platforms of claim 1, wherein the one or more functionalization layers are identical.

17. A chip sensor, comprising:

2 or more of the nano-sensor platforms of claim 1, wherein the one or more functionalization layers are different.

18. A universal microelectromechanical nano-sensor platform comprising;

a substrate including an upper surface, wherein the upper surface comprises an insulator or has an insulator layer thereon;

a microstructure conductive layer deposited in a pattern on the surface to make several devices, wherein the conductive layer comprises one or more filaments, and wherein the filaments are disposed above and parallel to the substrate configured such that there is an air gap between the filaments and the upper surface of the substrate; and

wherein filaments comprise a size/width less than 10 microns and a thickness of 1 micron or less.

19. The nano-sensor platform of claim 18, further comprising an insulation layer, wherein the insulation layer is configured such that the filaments remain exposed and are not covered by the insulation layer, but rather the insulation layer covers one or more conductive leads up to the filaments.

20. The nano-sensor platform of claim 18, wherein one or more functionalization layers are deposited on the exposed filament(s), wherein the one or more functionalization layers are adapted to provide one or more transducer platform classes selected from the group consisting of:

radiant, electrochemical, electronic, mechanical, magnetic, and thermal sensing.

21. The nano-sensor platform of claim 18, wherein the filaments comprise polysilicon, or a conductive material such as Pt, Pd, SiC, or metal oxide.

22. The nano-sensor platform of claim 18, wherein the bridges comprise a material with a temperature coefficient of resistance greater than 0.003 ohms/degree C.

23. The nano-sensor platform of claim 20, wherein the one or more functionalization layers are deposited such as to create a space on and/or between the filaments, and configured such that electrical properties are measured between the filaments.

24. The nano-sensor platform of claim 18, wherein at least one of the filaments is utilized as a heater.

25. The nano-sensor platform of claim 18, wherein the substrate is back etched to improve thermal isolation and allow lower power at high temperature.

26. The nano-sensor platform of claim 18, further comprising one or more temperature sensors and heaters located on an underneath layer.

27. The nano-sensor platform of claim 19, wherein an insulation layer is deposited on exposed filament(s) to increase robustness and/or insulates leads.

28. The nano-sensor platform of claim 27, further comprising a second conductive layer deposited on the insulation layer.

29. The nano-sensor platform of claim 28, wherein the second conductive layer covers the insulation layer and extends up to and/or onto the filaments so as to provide electrodes on the filaments.

30. The nano-sensor platform of claim 29, further comprising an additional functionalization layer applied to the bridge, wherein the additional functionalization layer is applied only up to and touching the electrode that extends up to or onto the bridge.

31. The nano-sensor platform of claim 20, wherein the functionalization layer is a nanostructure material.

32. The nano-sensor platform of claim 18, wherein the filaments are configured such that the devices can operate at elevated temperatures up to 500 C using less than 10 m/W.

38. The nano-sensor platform of claim 18, further comprising at least 2 pairs of filaments in the same or different areas of the same chip, wherein the filaments are disposed above and separated from the substrate with an air gap between the filaments and the surface of the substrate.

39. The nano-sensor platform of claim 38, wherein the first filament(s) is configured for upstream thermal conductivity detection and the second filament(s) is configured for downstream thermal conductivity detection.

40. The nano-sensor platform of claim 38, wherein the first pair of filaments has a catalyst deposited thereon, and wherein the second pair of filaments is inert.

33. A universal microelectromechanical nano-sensor platform comprising;

a semiconductor substrate including a surface;

a microstructure polysilicon layer deposited in a pattern on the surface to make several devices, wherein the polysilicon layer comprises a first pair of filaments, wherein the filaments are disposed above and parallel to the semiconductor substrate with an air gap between the base of the filaments and the surface of the substrate;

an insulation layer, wherein the insulation layer is configured such that the first pair of filaments of the polysilicon layer remain exposed and are not covered by the insulation layer;

one or more functionalization layers deposited on the exposed pair of filaments of the polysilicon layer, wherein the one or more functionalization layers are adapted to provide one or more transducer platform classes selected from the group consisting of;

radiant, electrochemical, electronic;

mechanical, and thermal; and

wherein the at least one pair of the filaments has a width of less than 10 microns.

34. The nano-sensor platform of claim 33, wherein at least one pair of filaments has a thickness of less than or equal to 1 micron.

35. The nano-sensor platform of claim 33, wherein the air gap has a height of 2-10 microns.

36. The nano-sensor platform of claim 33, wherein the air gap has a length of at least 100 microns.

37. The nano-sensor platform of claim 33, further comprising a temperature sensor and/or a heater under the surface of the substrate.