Micro-sensor

• US 7,427,808 B2
• Filed: 10/08/2002
• Issued: 09/23/2008
• Est. Priority Date: 10/29/2001
• Status: Expired due to Term

• Current Assignee: ScioSense B.V. (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Brandl, Manfred, Csernicska, Robert
• Primary Examiner(s): Rose; Kiesha L
• Application Number:
  US10/494,027
• Publication Number:
  US 20050067695A1
• Time in Patent Office: 2,177 Days
• Field of Search: 257/724
• US Class Current: 257/724
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81C 1/00238 Joining a substrate with an electronic processing unit and a substrate with a micromechanical structure
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/131 with electrostatic counterbalancing means
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Abstract

The present invention describes a microsensor with a sensor element (2) and an integrated circuit (1), containing a semiconductor body (11) with an intergrated circuit (4), the sensor element (2) being positioned on a main surface (12) of the semiconductor body (11) and there being a eutectic connection (3) formed between the semiconductor body (11) and the sensor element (2).

Claims

1. A microsensor comprising:

a sensor element comprising;

a first barrier layer; and

a micromechanical sensor element;

a semiconductor body comprising an integrated circuit and a second barrier layer, wherein the sensor element is on a surface of the semiconductor body, the micromechanical sensor element comprising a movable component comprising a spring strip configured to move a distance from the surface of the semiconductor body, the movable component and the semiconductor body defining a gap, a measurement signal being produced across the gap;

one or more electrodes configured to acquire a capacitive measurement indicative of the distance; and

a eutectic connection that couples the semiconductor body to the sensor element, the eutectic connection being between the first and second barrier layers, the first and second barrier layers limiting a thickness of the eutectic connection.

2. The microsensor of claim 1, wherein the integrated circuit is on a surface of the semiconductor body facing the sensor element.

3. The microsensor of claim 1, wherein the sensor element comprises a semiconductor material, a semiconductor layer, or a semiconductor substrate.

4. The microsensor of claim 3, wherein the semiconductor body and the sensor element contain similar semiconductor materials.

5. The microsensor of claim 4, wherein the semiconductor body and the sensor element both contain silicon.

6. The microsensor of claim 1, wherein the eutectic connection is formed using a metal layer adjacent to the second barrier layer.

7. The microsensor of claim 1, wherein the eutectic connection is formed using a semiconductor layer adjacent to the first barrier layer.

8. The microsensor of claim 6, wherein the metal layer comprises gold.

9. The microsensor of claim 8, wherein the integrated circuit is at least partly covered by the metal layer.

10. The microsensor of claim 1, wherein the thickness of the eutectic connection is determined by the first and second barrier layers.

11. The microsensor of claim 1, wherein the first barrier layer contains silicon oxide or silicon nitride.

12. The microsensor of claim 1, wherein the eutectic connection contains a silicon-gold eutectic.

13. The microsensor of claim 1, wherein the measurement signal is produced capacitively across the gap.

14. The microsensor of claim 8, wherein the integrated circuit is at least partly covered by the metal layer.

15. The microsensor of claim 1, wherein the eutectic connection is formed using a semiconductor layer adjacent to the first barrier layer and a metal layer adjacent to the second barrier layer, wherein the first barrier layer limits dispersion of atoms of the metal layer into the sensor element and the second barrier layer substantially prevents diffusion of metal atoms from the metal layer into the integrated circuit, wherein a thickness of the eutectic connection is determined by the first and second barrier layers.

16. The microsensor of claim 1, wherein the micromechanical sensor element is configured to sense an acceleration of the microsensor, wherein a distance between the spring strip and the surface of the semiconductor body depends on the acceleration.

17. The microsensor of claim 1, wherein the spring strip comprises a first end that is fixed and a second, opposite end that is moveable relative to the first end.

18. A microsensor comprising:

a sensor element comprising;

a first barrier layer; and

a micromechanical sensor element;

a semiconductor body comprising an integrated circuit and a second barrier layer, wherein the sensor element is on a surface of the semiconductor body, the micromechanical sensor element comprising a movable component comprising a spring strip, the movable component and the semiconductor body defining a gap, a measurement signal being produced across the gap; and

a eutectic connection that couples the semiconductor body to the sensor element, the eutectic connection being between the first and second barrier layers, the first and second barrier layers limiting a thickness of the eutectic connection,

wherein the micromechanical sensor element is configured to sense an acceleration of the microsensor, wherein a distance between the spring strip and the surface of the semiconductor body depends on the acceleration.

19. The microsensor of claim 18, wherein the integrated circuit is on a surface of the semiconductor body facing the sensor element.

20. The microsensor of claim 18, wherein the sensor element comprises a semiconductor material, a semiconductor layer, or a semiconductor substrate.

21. The microsensor of claim 20, wherein the semiconductor body and the sensor element contain similar semiconductor materials.

22. The microsensor of claim 21, wherein the semiconductor body and the sensor element both contain silicon.

23. The microsensor of claim 18, wherein the eutectic connection is formed using a metal layer adjacent to the second barrier layer.

24. The microsensor of claim 18, wherein the eutectic connection is formed using a semiconductor layer adjacent to the first barrier layer.

25. The microsensor of claim 23, wherein the metal layer comprises gold.

26. The microsensor of claim 25, wherein the integrated circuit is at least partly covered by the metal layer.

27. The microsensor of claim 18, wherein the thickness of the eutectic connection is determined by the first and second barrier layers.

28. The microsensor of claim 18, wherein the first barrier layer contains silicon oxide or silicon nitride.

29. The microsensor of claim 18, wherein the eutectic connection contains a silicon-gold eutectic.

30. The microsensor of claim 18, wherein the measurement signal is produced capacitively across the gap.

31. The microsensor of claim 25, wherein the integrated circuit is at least partly covered by the metal layer.

32. The microsensor of claim 18, wherein the eutectic connection is formed using a semiconductor layer adjacent to the first barrier layer and a metal layer adjacent to the second barrier layer, wherein the first barrier layer limits dispersion of atoms of the metal layer into the sensor element and the second barrier layer substantially prevents diffusion of metal atoms from the metal layer into the integrated circuit, wherein a thickness of the eutectic connection is determined by the first and second barrier layers.

33. The microsensor of claim 18, wherein the spring strip is configured to move a distance from the surface of the semiconductor body, and the microsensor further comprises:

one or more electrodes configured to acquire a capacitive measurement indicative of the distance.

34. The microsensor of claim 18, wherein the spring strip comprises a first end that is fixed and a second, opposite end that is moveable relative to the first end.