Methods of manufacturing a magnetic field sensor

Patent metadata

Field	Value
Publication number	US-9525129-B2
Application number	US-201615142721-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Mar 31, 2010
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A semiconductor process integrates three bridge circuits, each include magnetoresistive sensors coupled as a Wheatstone bridge on a single chip to sense a magnetic field in three orthogonal directions. The process includes various deposition and etch steps forming the magnetoresistive sensors and a plurality of flux guides on one of the three bridge circuits for transferring a “Z” axis magnetic field onto sensors orientated in the XY plane.

First claim

The invention claimed is:

1. A method of manufacturing an integrated magneto-resistive sensor, the method comprising:
forming a first plurality of magneto-resistive sensor elements on or over a substrate;
forming first conductors to electrically connect the first plurality of magneto-resistive sensor elements;
depositing an insulating material on or over the first plurality of magneto-resistive sensor elements; and
forming flux guides on or over the insulating material, wherein at least one flux guide is associated with at least one magneto-resistive sensor element of the first plurality of magneto-resistive sensor elements, and wherein the at least one flux guide is offset from the at least one magneto-resistive sensor element.

2. The method of claim 1 , wherein:
forming first conductors to electrically connect the first plurality of magneto-resistive sensor elements includes forming a first circuit by electrically connecting the magneto-resistive sensor elements of the first plurality of magneto-resistive sensor elements.

3. The method of claim 2 , wherein the first circuit is a bridge circuit, and wherein the method further includes:
connecting the bridge circuit to a voltage source.

4. The method of claim 1 , wherein forming the first plurality of magneto-resistive sensor elements includes electrically connecting the first plurality of magneto-resistive sensor elements to form a first bridge circuit.

5. The method of claim 1 , wherein the formed first conductors electrically connect the first plurality of magneto-resistive sensor elements to form a first circuit.

6. The method of claim 5 , wherein the first circuit is a bridge circuit.

7. The method of claim 1 , wherein the at least one flux guide includes at least one of nickel, a nickel alloy, iron, an iron alloy, cobalt, and a cobalt alloy.

8. The method of claim 1 , wherein the at least one flux guide is formed below the at least one magneto-resistive sensor element.

9. The method of claim 1 , wherein the at least one flux guide is formed above the at least one magneto-resistive sensor element.

10. The method of claim 1 , wherein the at least one flux guide is formed above or below the at least one magneto-resistive sensor element.

11. The method of claim 1 , wherein the magneto-resistive sensor elements are magnetic tunnel junction sensor elements.

12. The method of claim 1 , further comprising:
forming a second plurality of magneto-resistive sensor elements on or over the substrate; and
forming second conductors to electrically connect the second plurality of magneto-resistive sensor elements.

13. The method of claim 1 , further comprising:
connecting the first plurality of magneto-resistive sensor elements in a circuit such that, in operation, the circuit is configured to subtract a resistance of the least one magneto-resistive sensor element from a resistance of another magneto-resistive sensor element.

14. The method of claim 1 , further comprising:
forming a first bridge circuit by electrically connecting the magneto-resistive sensor elements of the first plurality of magneto-resistive sensor elements;
forming a second plurality of magneto-resistive sensor elements on or over the substrate; and
forming a second bridge circuit by electrically connecting the magneto-resistive sensor elements of the second plurality of magneto-resistive sensor elements.

15. The method of claim 1 , wherein forming the first plurality of magneto-resistive sensor elements includes:
forming a reference layer,
forming a sensing layer, and
forming an intermediate layer between the reference and sensing layers, wherein the intermediate layer includes an insulating material.

16. The method of claim 1 , wherein the sensing layer includes a magnetization direction configured to change when exposed to an external magnetic field.

Assignees

• Everspin Technologies Inc

Inventors

• Whig Renu
• Mather Phillip
• Smith Kenneth
• Aggarwal Sanjeev
• Slaughter Jon
• Rizzo Nicholas

Classifications

• H01L43/08

  Electricity · mapped topic

• G01R33/098

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• H01L43/02

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic