Method of manufacturing magnetic field detector

• US 7,858,400 B2
• Filed: 07/10/2008
• Issued: 12/28/2010
• Est. Priority Date: 12/14/2007
• Status: Expired due to Fees

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Suh, Jeongdae, Chung, Myungae
• Primary Examiner(s): Booth; Richard A.
• Application Number:
  US12/170,882
• Publication Number:
  US 20090155932A1
• Time in Patent Office: 901 Days
• Field of Search: 438/3, 438/49, 438 57- 81
• US Class Current: 438/3
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: G01R 33/1269 of molecules labeled with magnetic beads magnetic particles for bio assay G01N33/54326
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one galvanomagnetic or Hall-effect element covered by groups H10N50/00 - H10N52/00 MRAM devices H10B61/00

Abstract

Disclosed is a method of manufacturing a magnetic field detector having various structures that can be used as a high-density magnetic biosensor. An embodiment of the invention provides a method of manufacturing a magnetic field detector including a magnetoresistive element using a magnetic bead detecting thin film. The method includes: preparing a substrate; depositing the thin film on an upper surface of the substrate; and etching the thin film to form a ring-shaped magnetoresistive element.

Claims

1. A method of manufacturing a magnetic field detector using a thin film for detecting magnetic beads, the method comprising:

preparing a substrate;

depositing the thin film on an upper surface of the substrate;

etching the thin film to form a ring-shaped magnetoresistive element;

forming, on the upper surface of a substrate, electrode pads connected to the magnetoresistive element;

forming a protective layer that covers the magnetoresistive element and portions of the electrode pads; and

forming, on an upper surface of the protective layer, a magnetic bead limiting layer which has a ring-shape that encloses the entire surface of the magnetoresistive element, the magnetic bead limiting layer used for impounding a solution containing the magnetic beads.

2. The method of claim 1,

wherein the thin film is formed of any one of a giant magnetoresistive thin film, an anisotropic magnetoresistive thin film, a spin valve thin film, and a tunnel-type magnetoresistive thin film.

3. The method of claim 1,

wherein the thin film includes a pinned layer and a free layer.

4. The method of claim 1,

wherein the thin film is a laminate of a seed layer, an antiferromagnetic layer, a pinned layer, a gap layer, a free layer, and a protective layer formed in this order.

5. The method of claim 1,

wherein the magnetoresistive element is formed in any one of a circular ring shape, an elliptical ring shape, a square ring shape, and a rectangular ring shape.

6. The method of claim 1,

wherein, in the forming of the electrode pads, the electrode pads are formed of Ta or Au.

7. The method of claim 1,

wherein, in the forming of the electrode pads, the electrode pads are formed so as to be horizontally connected to the magnetoresistive element.

8. The method of claim 1,

wherein, in the forming of the electrode pads, the electrode pads are formed so as to be vertically and horizontally connected to the magnetoresistive element.

9. The method of claim 1,

wherein, in the forming of the protective layer, the protective layer is formed of SiO₂ or Si₃N₄.

10. The method of claim 1,

wherein, in the forming of the protective layer, the protective layer is formed with a thickness of 50 to 300 nm at room temperature.

11. The method of claim 1,

wherein, in the forming of the magnetic bead limiting layer, the magnetic bead limiting layer is formed using a photosensitive thin film.

12. The method of claim 1,

wherein, in the forming of the magnetic bead limiting layer, the magnetic bead limiting layer is formed with a thickness of 1 to 2 μ

m at room temperature.

13. The method of claim 1,

wherein the outside diameter of the magnetoresistive element is in a range of 100 nm to 30 μ

m.

14. The method of claim 1,

wherein the width of the magnetoresistive element is in a range of 100 nm to 5 μ

m.

15. The method of claim 1,

wherein a plurality of magnetoresistive elements are formed in a one-dimensional array.

16. The method of claim 1,

wherein a plurality of magnetoresistive elements are formed in a two-dimensional array, that is, in a matrix.