Method of producing an integrated micromagnet sensor assembly

• US 8,173,446 B2
• Filed: 12/21/2009
• Issued: 05/08/2012
• Est. Priority Date: 12/21/2009
• Status: Active Grant

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: General Electric Company
• Inventors: Huber, William Hullinger
• Primary Examiner(s): Wilczewski, Mary
• Assistant Examiner(s): Thomas, Toniae
• Application Number:
  US12/642,968
• Publication Number:
  US 20110151587A1
• Time in Patent Office: 869 Days
• Field of Search: 438/3, 438/48, 257/422, 257/425, 360/324
• US Class Current: 438/3
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/095 extraordinary magnetoresistance sensors
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A method of integrating a permanent bias magnet within a magnetoresistance sensor comprising depositing an alternating pattern of a metal material and a semiconductor material on or within a surface of an insulating substrate; depositing a mask on the surface of the insulating substrate to create an opening above the alternating pattern of metal material and semiconductor material; applying a magnetic paste within the opening above the alternating pattern of metal material and semiconductor material; curing the magnetic paste to form a hardened bias magnet; removing the mask; and magnetizing the hardened bias magnet by applying a strong magnetic field to the hardened bias magnet at a desired orientation.

Claims

1. A method of integrating a permanent bias magnet within a magnetoresistance sensor comprising:

depositing an alternating pattern of a metal material and a semiconductor material on or within a surface of an insulating substrate;

depositing a mask on the surface of the insulating substrate to create an opening above the alternating pattern of the metal material and the semiconductor material;

applying a magnetic paste within the opening above the alternating pattern of the metal material and the semiconductor material;

curing the magnetic paste to form a hardened bias magnet;

removing the mask; and

magnetizing the hardened bias magnet by applying a strong magnetic field to the hardened bias magnet at a desired orientation.

2. The method of claim 1, wherein the mask is a photoresist mask.

3. The method of claim 2, wherein the mask is a lithographic mask.

4. The method of claim 1, wherein the mask is a screen printed mask.

5. The method of claim 1, wherein the mask is formed using at least one of laser ablation, diamond sawing or chemical etching.

6. The method of claim 1, wherein the magnetic paste includes a magnetic powder and a binder that are blended together.

7. The method of claim 1, wherein the mask is removed using a stripping chemical.

8. The method of claim 1, wherein the hardened bias magnet is fabricated on a separate substrate and bonded to the insulating substrate above the alternating pattern of the metal material and the semiconductor material.

9. The method of claim 1, wherein the desired orientation is a perpendicular or parallel orientation.

10. The method of claim 1, wherein the magnetized hardened bias magnet generates a large perpendicular field over the magnetoresistance sensor.

11. A method of producing an integrated magnetoresistance sensor assembly including a permanent bias magnet comprising:

depositing an alternating pattern of a metal material and a semiconductor material on or within a surface of an insulating substrate;

depositing a photoresist mask on the surface of the insulating substrate in a pattern that covers the surface of the insulating substrate, but does not cover the alternating pattern of the metal material and the semiconductor material, leaving an opening above the alternating pattern of the metal material and the semiconductor material;

applying a magnetic paste over a surface of the photoresist mask and filling the opening above the alternating pattern of the metal material and the semiconductor material with the magnetic paste;

removing the magnetic paste from the surface of the photoresist mask;

curing the magnetic paste within the opening above the alternating pattern of the metal material and the semiconductor material to form a hardened bias magnet;

removing the photoresist mask from around the hardened bias magnet; and

applying a strong magnetic field to the hardened bias magnet at a desired orientation to magnetize the hardened bias magnet.

12. The method of claim 11, wherein the magnetic paste includes a magnetic powder and a binder that are blended together.

13. The method of claim 11, wherein the photoresist mask is removed using a stripping chemical.

14. The method of claim 11, wherein the hardened bias magnet is fabricated on a separate substrate and bonded to the insulating substrate above the alternating pattern of the metal material and the semiconductor material.

15. The method of claim 11, wherein the desired orientation is a perpendicular or parallel orientation.

16. The method of claim 11, wherein the magnetized hardened bias magnet generates a large perpendicular field over the magnetoresistance sensor.