Integrated magnetic flux concentrator

• US 7,358,724 B2
• Filed: 05/16/2005
• Issued: 04/15/2008
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Dickinson, Richard, Taylor, William P., Doogue, Michael C.
• Primary Examiner(s): Aurora; Reena
• Application Number:
  US11/129,933
• Publication Number:
  US 20060255797A1
• Time in Patent Office: 1,065 Days
• Field of Search: 324/260
• US Class Current: 324/260
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A method and apparatus provide a substrate having a depression into which a magnetic material is disposed, forming a magnetic flux concentrator and/or a permanent magnet. A magnetic field sensing element can be disposed proximate to the depression.

Claims

1. Apparatus, comprising:

a substrate having first and second opposing surfaces;

a magnetic field sensing element disposed on the first surface of the substrate, having first and second opposing magnetic field sensing element surfaces generally parallel to the first surface of the substrate;

a depression disposed in the second surface of the substrate and generally aligned with the magnetic field sensing element, wherein the depression has a first depression surface generally parallel to the first surface of the substrate and adjacent to the magnetic field sensing element and a second depression surface adjacent to the first depression surface; and

a magnetic material layer disposed on at least one of the first depression surface or the second depression surface.

2. The apparatus of claim 1, wherein the magnetic material layer is comprised of a soft magnetic material.

3. The apparatus of claim 1, wherein the magnetic material layer is comprised of a hard magnetic material.

4. The apparatus of claim 1, wherein the second depression surface is generally perpendicular to the first depression surface.

5. The apparatus of claim 1, wherein the magnetic material layer is formed from a selected one of a ferrite material, Permalloy, NiFeMo, Supermalloy, a Nickel alloy, an Iron alloy, a Cobalt alloy, or a Manganese alloy.

6. The apparatus of claim 1, wherein the magnetic material layer is disposed with a selected one of a plating process, a sputtering process, or an electron beam process.

7. The apparatus of claim 1, further comprising a soft magnetic material layer extension disposed on the second surface of the substrate.

8. The apparatus of claim 7, wherein the soft magnetic material layer extension is disposed with a selected one of a plating process, a sputtering process, or an electron beam process.

9. The apparatus of claim 1, wherein the depression is a deep reactive ion etch (DRIE) depression.

10. The apparatus of claim 1, further comprising a second magnetic material layer disposed on the first surface of the magnetic field sensing element surface.

11. The apparatus of claim 10, wherein the second magnetic material layer is comprised of a soft magnetic material.

12. The apparatus of claim 10, wherein the second magnetic material layer is comprised of a hard magnetic material.

13. The apparatus of claim 10, further comprising at least one of:

a first soft magnetic material layer extension disposed on the first surface of the substrate or a second soft magnetic material layer extension disposed on the second surface of the substrate.

14. The apparatus of claim 13, wherein the first soft magnetic material layer extension and the second soft magnetic material layer extension are disposed with a selected one of a plating process, a sputtering process, or an electron beam process.

15. The apparatus of claim 10, wherein the magnetic material layer is formed from a selected one of a ferrite material, Permalloy, NiFeMo, Supermalloy, a Nickel alloy, an Iron alloy, a Cobalt alloy, or a Manganese alloy.

16. The apparatus of claim 10, wherein the second magnetic material layer is disposed with a selected one of a plating process, a sputtering process or an electron beam process.

17. The apparatus of claim 1, wherein the magnetic field sensing element is responsive to a magnetic field associated with an electrical current.

18. The apparatus of claim 1, wherein the magnetic field sensing element is responsive to a magnetic field external to the apparatus.

19. The apparatus of claim 1, wherein the magnetic field sensing element is responsive to a magnetic field associated with at least one of a hard magnetic material object or a soft magnetic material object.

20. The apparatus of claim 1, further including a concentrator apparatus, comprising:

a second substrate having first and second opposing surfaces, wherein the second surface of the second substrate is disposed over a selected one of the first surface of the substrate or the second surface of the substrate and the first surface of the second substrate is disposed over the second surface of the second substrate;

a concentrator apparatus depression disposed in at least one of the first surface or the second surface of the second substrate and generally aligned with the magnetic field sensing element, wherein the concentrator apparatus depression has at least one of a first concentrator apparatus depression surface generally parallel to the second surface of the second substrate and a second concentrator apparatus depression surface; and

a concentrator apparatus magnetic material layer disposed on at least one of the first concentrator apparatus depression surface or the second concentrator apparatus depression surface.

21. The apparatus of claim 20, wherein the concentrator apparatus magnetic material layer is comprised of a soft magnetic material.

22. The apparatus of claim 20, wherein the concentrator apparatus magnetic material layer is comprised of a hard magnetic material.

23. The apparatus of claim 20, wherein the concentrator apparatus magnetic material layer is formed from a selected one of a ferrite material, Permalloy, NiFeMo, Supermalloy, a Nickel alloy, an Iron alloy, a Cobalt alloy, or a Manganese alloy.

24. The apparatus of claim 20, wherein the concentrator apparatus magnetic material layer is disposed with a selected one of a plating process, a sputtering process, or an electron beam process.

25. The apparatus of claim 20, wherein the concentrator apparatus depression is a deep reactive ion etch (DRIE) concentrator apparatus depression.

26. The apparatus of claim 20, further including:

a conductor having a first notch and a second notch substantially aligned with the first notch, wherein the magnetic field sensing element has at least a portion disposed in the first notch; and

a magnetic core having a central region and a pair of substantially parallel legs extending from said central region, wherein at least a portion of said central region is disposed in the second notch and wherein at least a portion of each leg covers at least a portion of a respective surface of the magnetic field sensing element.

27. The apparatus of claim 20, further including:

a lead frame having a plurality of leads;

a current conductor portion comprising a coupling of at least two of the plurality of leads, wherein the current conductor portion is disposed proximate the first surface of the substrate.

28. The apparatus of claim 1, further including:

a conductor having a first notch and a second notch substantially aligned with the first notch, wherein the magnetic field sensing element has at least a portion disposed in the first notch; and

a magnetic core having a central region and a pair of substantially parallel legs extending from said central region, wherein at least a portion of said central region is disposed in the second notch and wherein at least a portion of each leg covers at least a portion of a respective surface of the magnetic field sensing element.

29. The apparatus of claim 1, further including:

a lead frame having a plurality of leads;

a current conductor portion comprising a coupling of at least two of the plurality of leads, wherein the current conductor portion is disposed proximate the first surface of the substrate.