Sensor
A magnetic sensor includes an insulating layer, a first MR element, and a second MR element. The insulating layer includes a protruding surface including first and second inclined surfaces. Each of the first and second MR elements includes a magnetization pinned layer and a free layer. The magnetization pinned layer and the free layer of the first MR element are disposed on the first inclined surface. The magnetization pinned layer and the free layer of the second MR element are disposed on the second inclined surface. The dimension of the protruding surface in a direction parallel to the Z direction is in the range of 1.4 μm to 3.0 μm.
1. A sensor configured to detect a predetermined physical quantity, comprising:
a substrate including a top surface;
a support member disposed on the substrate; and
a sensor element configured to change in a physical property depending on the predetermined physical quantity, wherein
the sensor element is supported by the support member,
the support member includes a protruding surface protruding in a direction away from the top surface of the substrate and including at least one inclined surface,
the protruding surface includes an upper end portion farthest from the top surface of the substrate,
the protruding surface includes a first curved surface portion including the upper end portion of the protruding surface, and a second curved surface portion continuous with the first curved surface portion and located between the first curved surface portion and the top surface of the substrate in a direction perpendicular to the top surface of the substrate,
the first curved surface portion is a curved surface protruding in the direction away from the top surface of the substrate,
the second curved surface portion is a curved surface protruding in a direction closer to the top surface of the substrate, and
a radius of curvature of the second curved surface portion in a cross section perpendicular to the top surface of the substrate is smaller than a radius of curvature of the first curved surface portion in the cross section perpendicular to the top surface of the substrate, and is greater than or equal to 0.3 μm.
2. The sensor according to claim 1 , wherein the radius of curvature of the first curved surface portion in the cross section is greater than or equal to 4.25 μm and less than or equal to 5.45 μm.
3. The sensor according to claim 1 , wherein
the first curved surface portion includes a first portion including the upper end portion of the protruding surface, and a second portion continuous with the first portion at a position away from the upper end portion of the protruding surface, and
when a shape of the protruding surface in the cross section is regarded as a function Z having as a variable a position on a virtual straight line that is parallel to each of the cross section and the top surface of the substrate, a mean value of an absolute value of a second derivative Z″ of the function Z corresponding to the first portion is smaller than a mean value of an absolute value of the second derivative Z″ of the function Z corresponding to the second portion.
4. The sensor according to claim 3 , wherein a value of the second derivative Z″ of the function Z corresponding to the first curved surface portion is less than or equal to 0.
5. The sensor according to claim 1 , wherein the at least one inclined surface includes two inclined surfaces facing different directions.
6. The sensor according to claim 5 , wherein the two inclined surfaces are symmetrical about a virtual plane perpendicular to the top surface of the substrate as a center.
7. The sensor according to claim 1 , wherein
the support member includes a first layer and a second layer formed on the first layer, and
the at least one inclined surface is formed across the first layer and the second layer.
8. The sensor according to claim 7 , wherein:
the at least one inclined surface includes a first end edge closest to the top surface of the substrate, and a second end edge farthest from the top surface of the substrate,
the first end edge is located in the first layer, and
the second end edge is located in the second layer.
9. The sensor according to claim 8 , wherein
the first layer includes a first end portion closest to the top surface of the substrate, and a second end portion farthest from the top surface of the substrate, and
the first end edge is disposed between the first end portion of the first layer and the second end portion of the first layer in the direction perpendicular to the top surface of the substrate.
10. The sensor according to claim 9 , wherein the sensor element is disposed along a surface of the second layer, but is not disposed along a surface of the first layer.
11. The sensor according to claim 8 , wherein the at least one inclined surface includes no step at a position of a boundary between the first layer and the second layer.
12. The sensor according to claim 7 , wherein
each of the first layer and the second layer includes a first end portion closest to the top surface of the substrate, and a second end portion farthest from the top surface of the substrate, and
a distance from an interface between the first layer and the second layer to the first end portion of the first layer is shorter than a distance from the interface between the first layer and the second layer to the second end portion of the second layer.
13. The sensor according to claim 7 , wherein the at least one inclined surface is a smooth curved surface as a whole.
14. The sensor according to claim 7 , wherein each of the first layer and the second layer is formed of an insulating material.
15. The sensor according to claim 7 , further comprising a structure embedded in the first layer, wherein
the structure includes an end surface farthest from the top surface of the substrate, and
the end surface of the structure is disposed at substantially a same position as an interface between the first layer and the second layer in a direction perpendicular to the top surface of the substrate.
16. The sensor according to claim 1 , wherein
the predetermined physical quantity is at least one of a direction or a strength of a target magnetic field, and
the sensor element is a magnetic detection element configured to detect a change in at least one of the direction or the strength of the target magnetic field.