Integrated Three-Dimensional Magnetic Sensing Device and Method to Fabricate an Integrated Three-Dimensional Magnetic Sensing Device

• US 20070035294A1
• Filed: 10/02/2006
• Published: 02/15/2007
• Est. Priority Date: 06/03/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Peczalski, Andrzej, Wan, Hong, Witcraft, William, Detry, James
• Granted Patent: US 7,358,722 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence
• CPC Class Codes: G01R 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00

Abstract

An integrated three-dimensional magnetic or any field sensing device and a method to fabricate an integrated three-dimensional magnetic sensing device is presented. An integrated three-dimensional magnetic sensing device comprises an apparatus that defines at least a first surface area and at least one sloped surface which is sloped with respect to the first surface area. Two magnetic sensing units could be arranged on the first surface area to provide first and second orthogonal sensing directions, and a third magnetic sensing unit could be arranged on the at least one sloped surface to provide sensing in at least a third sensing direction which is orthogonal to the first and second orthogonal sensing directions. Bias could be applied to the third magnetic sensing unit to cancel a component of the magnetic field sensed by the third magnetic sensing unit so that the third magnetic sensor unit only provides sensing in the third direction.

Claims

1-32. -32. (canceled)

33. An integrated three-dimensional generic field sensing device comprising:

a substrate having a first surface and a second surface, wherein the second surface is sloped with respect to the first surface, and wherein the second surface is formed by performing KOH etching to the substrate;

a first field sensor unit and a second field sensor unit, wherein the first field sensor unit and the second field sensor unit are formed in a common plane on the first surface of the substrate; and

a third field sensor unit formed on the sloped second surface,

wherein the first field sensor unit senses a component of a field in a first direction, the second field sensor unit senses a component of the field in a second direction, and the third field sensor unit senses a component of the field in a third direction, and

wherein the first direction, the second direction, and the third direction are substantially mutually orthogonal.

34. The integrated three-dimensional generic field sensing device of claim 33, wherein the substrate is a silicon substrate.

35. The integrated three-dimensional generic field sensing device of claim 33, wherein the substrate is a germanium substrate.

36. An integrated three-dimensional magnetic sensing device comprising:

a substrate having a first surface and a second surface, wherein the second surface is sloped with respect to the first surface, and wherein the second surface is formed by performing KOH etching to the substrate;

a first magnetic sensor unit and a second magnetic sensor unit, wherein the first magnetic sensor unit and the second magnetic sensor unit are formed in a common plane on the first surface of the substrate; and

a third magnetic sensor unit formed on the sloped second surface,

wherein the first magnetic sensor unit senses a component of a magnetic field in a first direction, the second magnetic sensor unit senses a component of the magnetic field in a second direction, and the third magnetic sensor unit senses a component of the magnetic field in a third direction, and

wherein the first direction, the second direction, and the third direction are substantially mutually orthogonal.

37. The integrated three-dimensional magnetic sensing device of claim 36,

wherein the first magnetic sensor unit comprises a first plurality of magnetoresistive strips and a first set of interconnections to couple the first plurality of magnetoresistive strips as a first electrical circuit,

wherein the second magnetic sensor unit comprises a second plurality of magnetoresistive strips and a second set of interconnections to couple the second plurality of magnetoresistive strips as a second electrical circuit, and

wherein the third magnetic sensor unit comprises a third plurality of magnetoresistive strips and a third set of interconnections to couple the third plurality of magnetoresistive strips as a third electrical circuit.

38. The integrated three-dimensional magnetic sensing device of claim 37,

wherein the first electrical circuit is arranged as a first Wheatstone bridge, wherein the second electrical circuit is arranged as a second Wheatstone bridge, and the third electrical circuit is arranged as a third Wheatstone bridge.

39. The integrated three-dimension magnetic sensing device of claim 36, wherein the first, second, and third plurality of magnetoresistive strips comprise a magnetoresistive material.

40. The integrated three-dimensional magnetic sensing device of claim 39, wherein the magnetoresistive material is selected from the group consisting of:

(i) anisotropic magnetoresistive (AMR) material, (ii) giant magnetoresistive (GMR) material, and (iii) colossal magnetoresistive (CMR) material.

41. The integrated three-dimensional magnetic sensing device of claim 36,

wherein the first magnetic sensor unit comprises a first sensor output for outputting a first signal that represents the component of the magnetic field in the first direction,

wherein the second magnetic sensor unit comprises a second sensor output for outputting a second signal that represents the component of the magnetic field in the second direction, and

wherein the third magnetic sensor unit comprises a third sensor output for outputting a signal representing the component of the magnetic field in the third direction.

42. The integrated three-dimensional magnetic sensing device of claim 36, wherein the first magnetic sensor unit comprises a first Hall-effect sensor, the second magnetic sensor unit comprises a second Hall-effect sensor, and the third magnetic sensor unit comprises a third Hall-effect sensor.

43. The integrated three-dimensional magnetic sensing device of claim 36, wherein the first magnetic sensor unit comprises a first giant magnetoresistive sensor, the second magnetic sensor unit comprises a second giant magnetoresistive sensor, and the third magnetic sensor unit comprises a third giant magnetoresistive sensor.

44. The integrated three-dimensional magnetic sensing device of claim 36, wherein the first magnetic sensor unit comprises a first spin tunnel device sensor, the second magnetic sensor unit comprises a second spin tunnel device sensor, and the third magnetic sensor unit comprises a third spin tunnel device sensor.

45. The integrated three-dimensional magnetic sensing device of claim 36, wherein the first magnetic sensor unit comprises a first giant magneto-impedance device sensor, the second magnetic sensor unit comprises a second giant magneto-impedance sensor, and the third magnetic sensor unit comprises a third giant magneto-impedance sensor.

46. A method of fabricating an integrated three-dimensional magnetic sensing device, the method comprising:

etching a substrate to form at least one sloped surface of the substrate, wherein the at least one slope surface is sloped with respect to a first surface area of the substrate and with respect to a second surface area of the substrate;

forming a first magnetic sensor unit on the first surface area of the substrate such that the first magnetic sensor unit senses a component of a magnetic field in a first direction;

forming a second magnetic sensor unit on the second surface area of the substrate such that the second magnetic sensor unit senses a component of a magnetic field in a second direction; and

forming a third magnetic sensor unit on the at least one sloped surface of the substrate such that the third magnetic sensor unit senses a component of a magnetic field in a third direction,

wherein the first direction, the second direction, and the third direction are mutually orthogonal directions.

47. The method of claim 46,

wherein forming the first magnetic sensor unit further comprises depositing a first set of magnetoresistive strips on the first surface area,

wherein forming the second magnetic sensor unit further comprises depositing a second set of magnetoresistive strips on the second surface area, and

wherein forming the third magnetic sensor unit further comprises depositing a third set of magnetoresistive strips on the at least one sloped surface.

48. The method of claim 47,

wherein forming the first magnetic sensor unit further comprises depositing a first set of conductive straps on the first set of magnetoresistive strips,

wherein forming the second magnetic sensor unit further comprises depositing a second set of conductive straps on the second set of magnetoresistive strips,

wherein forming the third magnetic sensor unit further comprises depositing a third set of conductive straps on the third set of magnetoresistive strips, and

wherein the first, second, and third sets of conductive straps are arranged to form angles of approximately 45 degrees with respect to the first, second, and third sets of magnetoresistive strips, respectively, and

wherein the first, second, and third sets of conductive straps provide a linear operating range for the first, second, and third sets of magnetoresistive strips.

49. The method of claim 48, further comprising:

arranging a conductor in proximity to the third magnetic sensor unit,

wherein passing a current through the conductor aligns a magnetization vector of the third magnetic sensor unit.

50. The method of claim 49, further comprising:

coupling interconnections to the first set of magnetoresistive strips to form a first resistor bridge network;

coupling interconnections to the second set of magnetoresistive strips to form a second resistor bridge network; and

coupling interconnections to the third set of magnetoresistive strips to form a third resistor bridge network.

51. The method of claim 46, wherein etching the substrate to form the at least one sloped surface of the substrate comprises etching a semiconductor chip via KOH etching.

52. The method of claim 46, wherein etching the substrate to form the at least one sloped surface of the substrate comprises etching the substrate via KOH etching.

53. The method of claim 46,

wherein the at least one sloped surface includes a first sloped surface and a second sloped surface,

wherein the first sloped surface is opposite the second sloped surface, and

wherein the third direction is vertical to the first surface area and the second surface area,

the method further comprising:

arranging on the third magnetic sensor unit a biasing means for cancelling at the third magnetic sensor unit magnetic field components parallel to the first surface area and the second surface area,

whereby the third magnetic sensor unit detects components of the magnetic field in the third direction.