Process integration of a single chip three axis magnetic field sensor
AssigneeEverspin Technologies, Inc.
InventorsRenu WHIG, Phillip MATHER, Kenneth SMITH, Sanjeev AGGARWAL, Jon SLAUGHTER, Nicholas RIZZO
Life of this patent
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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.
Claims21
1-27. (canceled)
A method of sensing an out-of-plane component of a magnetic field, the method comprising:
- exposing a single chip magnetic sensor to the magnetic field, wherein the single chip magnetic sensor includes a plurality of differential sensors deposited in a single plane, each differential sensor of the plurality of differential sensors including a plurality of magneto-resistive sensor elements coupled together in an electrical circuit, wherein the magneto-resistive sensor elements of a first differential sensor of the plurality of differential sensors comprise:
- a high magnetic permeability flux guide formed within a first dielectric layer;
- and
- a sensor element adjacent the high magnetic permeability flux guide, wherein the sensor element is includes a reference layer, an intermediate layer on the reference layer, and a sensing layer on the intermediate layer.
A method of sensing an out-of-plane component of a magnetic field, the method comprising:
- exposing a single chip magnetic sensor to the magnetic field, wherein the single chip magnetic sensor includes a plurality of differential sensors deposited in a single plane, each differential sensor of the plurality of differential sensors including a plurality of magneto-resistive sensor elements electrically coupled together, wherein the magneto-resistive sensor elements of a first differential sensor of the plurality of differential sensors comprise:
- a sensor element including a reference layer, an intermediate layer on the reference layer, and a sensing layer on the intermediate layer;
- and
- a flux guide adjacent the sensor element, wherein the flux guide is configured to guide the out-of-plane component of the magnetic field to the sensor element.
A method of manufacturing an integrated three axis magneto-resistive sensor, the method comprising:
- forming a first plurality of magneto-resistive sensor elements on a first insulating material, wherein forming the first plurality of magneto-resistive sensor elements includes:
- forming a first reference layer,
- forming a first intermediate layer on the first reference layer, and
- forming a first sensing layer on the first intermediate layer;
- forming a first bridge circuit by electrically interconnecting the magneto-resistive sensor elements of the first plurality of magneto-resistive sensor elements;
- depositing a second insulating material on the first plurality of magneto-resistive sensor elements;
- etching a plurality of first trenches in the second insulating material, wherein each first trench includes at least two side walls, and wherein each first trench is juxtaposed to and laterally offset from an associated magneto-resistive sensor element of the first plurality of magneto-resistive sensor elements;
- forming a plurality of first flux guides in the plurality of first trenches, wherein each first flux guide includes a magnetic material deposited on the at least two side walls of an associated first trench;
- and
- depositing a third insulating material on the second insulating material and the first flux guides.
Dependencies are inferred from the claim text.