SURFACE ACOUSTIC WAVE SENSOR ASSEMBLIES

• US 20090115004A1
• Filed: 12/17/2004
• Published: 05/07/2009
• Est. Priority Date: 12/30/2003
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Free, Michael B., Johnston, Raymond P., Carter, Chad J., Huizinga, John S.
• Application Number:
  US10/596,954
• Publication Number:
  US 20090115004A1
• Time in Patent Office: Days
• US Class Current: 257/414
• CPC Class Codes: G01N 2291/021 Gases
• CPC Class Codes: G01N 2291/022 Liquids
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/222 Constructional or flow details for analysing fluids optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/2462 Probes with waveguides, e.g. SAW devices
• CPC Class Codes: H01L 24/80 Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H05K 2201/0314 Elastomeric connector or conductor, e.g. rubber with metallic filler elastomeric dielectric H05K2201/0133
• CPC Class Codes: H05K 2201/09072 Hole or recess under component or special relationship between hole and component
• CPC Class Codes: H05K 2201/10083 Electromechanical or electro-acoustic component, e.g. microphone
• CPC Class Codes: H05K 2203/1147 Sealing or impregnating, e.g. of pores
• CPC Class Codes: H05K 3/325 : by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor adaptations of leads inserted in holes for press-fit connections H05K3/308

Abstract

The invention is directed to a surface acoustic wave sensor assembly that makes use of a Z-axis conductive layer, such as a Z-axis conductive elastomer, or the like. In particular, a Z-axis conductive elastomer couples a circuit layer to a surface acoustic wave (SAW) sensor in order to form a SAW sensor assembly. For example, a plurality of electrical contacts of the circuit layer can be coupled to a plurality of electrodes of the SAW sensor via the Z-axis conductive elastomer. The Z-axis conductive elastomer provides electrical coupling between the electrical contacts and the electrodes, and also forms a hermetic barrier between the circuit layer and the SAW sensor. In addition, elastic properties of the Z-axis conductive elastomer may reduce pressure exerted on the SAW sensor during use.

Claims

1. A surface acoustic wave sensor assembly comprising:

a surface acoustic wave sensor comprising a plurality of electrodes;

a circuit layer including an aperture and a plurality of electrical contacts; and

a Z-axis conductive layer to couple the electrical contacts to the electrodes.

2. The surface acoustic wave sensor assembly of claim 1, wherein the Z-axis conductive layer comprises a Z-axis conductive elastomer.

3. The surface acoustic wave sensor assembly of claim 2, wherein the Z-axis conductive elastomer forms a hermetic barrier between the surface acoustic wave sensor and the circuit layer.

4. The surface acoustic wave sensor assembly of claim 1, wherein the surface acoustic wave sensor forms part of a sensor cartridge and the surface acoustic wave sensor is exposed to a fluid path within the cartridge via the aperture.

5. The surface acoustic wave sensor assembly of claim 1, wherein the surface acoustic wave sensor comprises a Love mode shear-horizontal surface acoustic wave sensor.

6. The surface acoustic wave sensor assembly of claim 1, wherein the electrical contacts of the circuit layer comprise circuit traces formed on the circuit layer.

7. The surface acoustic wave sensor assembly of claim 1, wherein the electrodes are located at a periphery of the sensor.

8. A sensor cartridge comprising:

a housing comprising a fluid path; and

a surface acoustic wave sensor assembly comprising a surface acoustic wave sensor that comprises a plurality of electrodes, a circuit layer that comprises an aperture and a plurality of electrical contacts, and a Z-axis conductive layer to couple the electrical contacts to the electrodes, wherein the surface acoustic wave sensor is exposed to the fluid path via the aperture.

9. The sensor cartridge of claim 8, wherein the plurality of electrical contacts are not exposed to the fluid path.

10. The sensor cartridge of claim 8, wherein the Z-axis conductive layer comprises a Z-axis conductive elastomer.

11. The sensor cartridge of claim 10, wherein the Z-axis conductive elastomer forms a hermetic barrier between the surface acoustic wave sensor and the circuit layer.

12. The sensor cartridge of claim 8, wherein the surface acoustic wave sensor comprises a Love mode shear-horizontal surface acoustic wave sensor.

13. The sensor cartridge of claim 8, wherein the housing comprises an input port to the fluid path.

14. The sensor cartridge of claim 13, wherein the fluid path comprises an input reservoir proximate the input port, an output reservoir, and a channel between the input reservoir and output reservoir, wherein the aperture is proximate the channel.

15. The sensor cartridge of claim 14, further comprising sorbent material inside the output reservoir.

16. The sensor cartridge of claim 15, wherein the housing comprises an output vent proximate the output reservoir.

17. The sensor cartridge of claim 8, wherein the housing comprises an air reservoir an opposing side of the surface acoustic wave sensor relative to the fluid path.

18. The sensor cartridge of claim 8, wherein the electrical contacts of the circuit layer comprise circuit traces formed on the circuit layer.

19. A method of forming a surface acoustic wave assembly comprising electrically coupling a plurality of electrodes of a surface acoustic wave sensor to a plurality of electrical contacts of a circuit layer with a Z-axis conductive layer.

20. The method of claim 19, further comprising providing an aperture in the circuit layer such that when the a plurality of electrodes are coupled to the plurality of electrical contacts of a circuit layer with a Z-axis conductive layer, the surface acoustic wave sensor is exposed via the aperture.

21. The method of claim 19, wherein the Z-axis conductive layer comprises a Z-axis conductive elastomer.

22. The method of claim 21, wherein the Z-axis conductive elastomer forms a hermetic barrier between the surface acoustic wave sensor and the circuit layer.

23. The method of claim 19, wherein the surface acoustic wave sensor comprises a Love mode shear-horizontal surface acoustic wave sensor.