US-12625203-B2 - Magnetic system including a magnetoresistive element disposed on an inclined surface

US12625203B2US 12625203 B2US12625203 B2US 12625203B2US-12625203-B2

Abstract

A magnetic sensor includes a substrate having a reference plane, a support member having an inclined surface, and a magnetoresistive element disposed on the inclined surface. The magnetoresistive element has a bottom surface, a top surface, and a first side surface and a second side surface connecting the bottom surface and the top surface. The first side surface is, as compared to the second side surface, located in front in a first direction that is along the inclined surface and that gets close to the reference plane. At least a part of the first side surface is, as compared to a first virtual plane, located close to the second side surface, and the first virtual plane intersects with a first corner present at a position at where the top surface and the first side surface intersect and is perpendicular to the reference plane.

Inventors

Hidekazu Kojima
Keita Kawamori
Hiromichi Umehara
Yoshitaka Sasaki

Assignees

TDK CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240515

Claims (15)

1 . A magnetic sensor comprising: a substrate having a reference plane; a support member that is disposed on the substrate and that has an inclined surface inclined relative to the reference plane; and a magnetoresistive element disposed on the inclined surface, wherein the magnetoresistive element has a bottom surface facing the inclined surface, a top surface located opposite to the bottom surface, and a first side surface and a second side surface connecting the bottom surface and the top surface, the first side surface is, as compared to the second side surface, located in front in a first direction that is along the inclined surface and that gets close to the reference plane, the second side surface is, as compared to the first side surface, located in front in a second direction that is along the inclined surface and that gets away from the reference plane, and at least a part of the first side surface is, as compared to a first virtual plane, located close to the second side surface, and the first virtual plane intersects with a first corner present at a position at where the top surface and the first side surface intersect and is perpendicular to the reference plane.
2 . The magnetic sensor according to claim 1 , wherein an angle that the at least a part of the first side surface forms with respect to a second virtual plane is in a range of 0° to 20°, and the second virtual plane intersects with the first corner and is perpendicular to the inclined surface.
3 . The magnetic sensor according to claim 1 , wherein the first side surface includes a first portion and a second portion located between the first portion and the support member, and an angle that the second portion forms with respect to a second virtual plane is greater than an angle that the first portion forms with respect to the second virtual plane, and the second virtual plane intersects with the first corner and is perpendicular to the inclined surface.
4 . The magnetic sensor according to claim 3 , wherein the magnetoresistive element includes a free layer having a magnetization whose direction is variable depending on an external magnetic field, a magnetization pinned layer having a magnetization whose direction is fixed, and a gap layer located between the free layer and the magnetization pinned layer, and a border between the first portion and the second portion is located at the magnetization pinned layer or the gap layer.
5 . The magnetic sensor according to claim 1 , wherein the magnetoresistive element includes a free layer having a magnetization whose direction is variable depending on an external magnetic field, a magnetization pinned layer that has a magnetization whose direction is fixed and that is interposed between the free layer and the inclined surface, and a gap layer located between the free layer and the magnetization pinned layer.
6 . The magnetic sensor according to claim 5 , wherein the magnetoresistive element further includes a cap layer that is formed of a nonmagnetic metal and that is located on the free layer.
7 . The magnetic sensor according to claim 1 , wherein an angle that the at least a part of the first side surface forms with respect to at least a part of the second side surface is smaller than an angle that the at least a part of the second side surface forms with respect to a third virtual plane, and the third virtual plane intersects with a second corner present at a position at where the top surface and the second side surface intersect and is perpendicular to the reference plane.
8 . The magnetic sensor according to claim 1 , wherein the second side surface includes a third portion and a fourth portion located between the third portion and the support member, and an angle that the fourth portion forms with respect to a fourth virtual plane is greater than an angle that the third portion forms with respect to the fourth virtual plane, and the fourth virtual plane intersects with a second corner present at a position at where the top surface and the second side surface intersect and is perpendicular to the inclined surface.
9 . The magnetic sensor according to claim 1 , further comprising: a different magnetoresistive element, wherein the inclined surface includes a first surface and a second surface oriented in directions different from each other, the magnetoresistive element is disposed on the first surface, and the different magnetoresistive element is disposed on the second surface.
10 . The magnetic sensor according to claim 1 , wherein an angle that a part, of the inclined surface, facing the magnetoresistive element forms with respect to the reference plane is in a range of 10° to 50°.
11 . A manufacturing method for the magnetic sensor according to claim 1 , the manufacturing method comprising: a step of forming the support member on the substrate; and a step of forming the magnetoresistive element, wherein the step of forming the magnetoresistive element includes a step of forming a layered film on the inclined surface of the support member, the layered film including a plurality of magnetic layers, a step of forming a protective layer on the layered film, a step of forming a mask, a first etching step of etching a part of the protective layer by using the mask, and a second etching step of etching the layered film by using the mask and the protective layer etched, so that the layered film serves as the magnetoresistive element.
12 . The manufacturing method for the magnetic sensor according to claim 11 , further comprising: a step of forming an insulating layer after the second etching step, and a step of removing the protective layer after the step of forming the insulating layer.
13 . The manufacturing method for the magnetic sensor according to claim 11 , wherein the magnetic sensor further includes a different magnetoresistive element, the inclined surface includes a first surface and a second surface oriented in directions different from each other, the magnetoresistive element is disposed on the first surface, the different magnetoresistive element is disposed on the second surface, and the magnetoresistive element and the different magnetoresistive element are formed at the same time in the second etching step.
14 . The manufacturing method for the magnetic sensor according to claim 11 , wherein the magnetic sensor further includes a different magnetoresistive element, the inclined surface includes a first surface and a second surface oriented in directions different from each other, the magnetoresistive element is disposed on the first surface, the different magnetoresistive element is disposed on the second surface, the second etching step includes a step of forming the magnetoresistive element by etching a part of the layered film, and a step of forming the different magnetoresistive element by etching another part of the layered film after the step of forming the magnetoresistive element.
15 . The manufacturing method for the magnetic sensor according to claim 11 , wherein the protective layer is formed of carbon or alumina.

Description

BACKGROUND The technology relates to a magnetic sensor including a magnetoresistive element disposed on an inclined surface. Magnetic sensors using magnetoresistive elements have been used for various applications in recent years. A system including a magnetic sensor may be intended to detect a magnetic field containing a component in a direction perpendicular to the surface of a substrate by using a magnetoresistive element provided on the substrate. In such a case, the magnetic field containing the component in the direction perpendicular to the surface of the substrate can be detected by providing a soft magnetic body for converting a magnetic field in the direction perpendicular to the surface of the substrate into a magnetic field in a direction parallel to the surface of the substrate or locating the magnetoresistive element on an inclined surface formed on the substrate. US 2008/0,316,654 A1 discloses a three-axis magnetic sensor including a plurality of giant magnetoresistive elements formed on a flat surface and a plurality of giant magnetoresistive elements formed on an inclined surface. US 2021/0,302,511 A1 discloses a magnetic sensor including a plurality of magnetoresistive elements disposed on an inclined surface. In these magnetic sensors, a side surface of the magnetoresistive elements has a forward-tapered shape relative to the inclined surface. In magnetic sensors, in order to suppress change in output in a case that the strength of a magnetic field applied is zero, a free layer may have a shape magnetic anisotropy. However, when a side surface of a magnetoresistive element has a tapered shape, such a shape magnetic anisotropy of the free layer is caused to be small. The shape magnetic anisotropy of the free layer can be made greater by making the width of the magnetoresistive element narrower. This, however, causes the sensitivity of the magnetoresistive element to be lowered. These problems are significant when the magnetoresistive element is disposed on an inclined surface. SUMMARY A magnetic sensor according to an embodiment of the technology includes a substrate having a reference plane, a support member that is disposed on the substrate and that has an inclined surface inclined relative to the reference plane, and a magnetoresistive element disposed on the inclined surface. The magnetoresistive element has a bottom surface facing the inclined surface, a top surface located opposite to the bottom surface, and a first side surface and a second side surface connecting the bottom surface and the top surface. The first side surface is, as compared to the second side surface, located in front in a first direction that is along the inclined surface and that gets close to the reference plane. The second side surface is, as compared to the first side surface, located in front in a second direction that is along the inclined surface and that gets away from the reference plane. At least a part of the first side surface is, as compared to a first virtual plane, located close to the second side surface, and the first virtual plane intersects with a first corner present at a position at where the top surface and the first side surface intersect and is perpendicular to the reference plane. In the magnetic sensor according to an embodiment of the technology, the magnetoresistive element is disposed on the inclined surface. At least a part of the first side surface of the magnetoresistive element is, as compared to the first virtual plane, located close to the second side surface of the magnetoresistive element. With this, an embodiment of the technology enables suppression of occurrence of a problem due to the shape of a side surface of the magnetoresistive element disposed on the inclined surface. Other and further objects, features and advantages of the technology will appear more fully from the following description. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments and, together with the specification, serve to explain the principles of the technology. FIG. 1 is a perspective view showing a magnetic sensor device including a magnetic sensor according to a first example embodiment of the technology. FIG. 2 is a plan view showing the magnetic sensor device shown in FIG. 1. FIG. 3 is a functional block diagram showing a configuration of the magnetic sensor device shown in FIG. 1. FIG. 4 is a circuit diagram showing a circuit configuration of a first detection circuit of the first example embodiment of the technology. FIG. 5 is a circuit diagram showing a circuit configuration of a second detection circuit of the first example embodiment of the technology. FIG. 6 is a circuit diagram showing a circuit configuration of a third detection circuit of the first example embodiment of the technology. FIG. 7 is a plan vie