sensor

Abstract

To realize a sensor in which the height of a protruding surface can be reduced.SOLUTION: A magnetic sensor 1 includes an insulating layer 305 including a protruding surface 305c, a first MR element 50B and a second MR element 50C. The protruding surface 305c includes a first inclined surface portion 305c1. The first inclined surface portion 305c1 includes a first portion c11 including an upper end E1 of the protruding surface 305c and a second portion c12 continuing to the first portion c11 at a position away from the upper end E1 of the protruding surface 305c. When the shape of the protruding surface 305c is regarded as a function Z, the average value of the absolute values of values of a secondary derivative Z" of the function Z corresponding to the first portion c11 is smaller than the average value of the absolute values of values of the secondary derivative Z" of the function Z corresponding to the second portion c12.SELECTED DRAWING: Figure 16

Description

Technical Field

[0001] The present invention relates to a sensor in which a sensor element is arranged on a convex surface.

Background Art

[0002] In recent years, magnetic sensors using magnetoresistive elements have been used in various applications. In a system including a magnetic sensor, there are cases where it is desired to detect a magnetic field including a component in a direction perpendicular to the surface of a substrate by a magnetoresistive element provided on the substrate. In this case, by providing a soft magnetic body that converts a magnetic field in a direction perpendicular to the surface of the substrate into a magnetic field in a direction parallel to the surface of the substrate, or by arranging the magnetoresistive element on an inclined surface formed on the substrate, a magnetic field including a component in a direction perpendicular to the surface of the substrate can be detected.

[0003] Patent Document 1 discloses a magnetic sensor in which an X-axis sensor, a Y-axis sensor, and a Z-axis sensor are provided on a substrate. The magnetoresistive element constituting the Z-axis sensor is provided on a second inclined surface, which is a flat inclined surface in the lower half, of the inclined surface of a V-shaped groove formed by partially cutting away a thick film. The second inclined surface is steeper than a first inclined surface, which is a flat inclined surface in the upper half, of the inclined surface of the V-shaped groove. The end portion of the first inclined surface on the side opposite to the second inclined surface is connected to the top of the groove, which is a flat surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In cases where the convex surface on which the magnetoresistive element is formed has multiple flat surfaces, such as in the magnetic sensor disclosed in Patent Document 1, attempting to pattern the magnetoresistive element or electrodes formed on the slope of the groove using photolithography can cause halation due to multiple corners formed by the intersection of two surfaces, resulting in distortion of the shape of the photoresist mask. Therefore, it is preferable that the convex surface is curved overall so that no corners are formed.

[0006] Incidentally, from the viewpoint of reducing the profile of magnetic sensors, it is preferable for the height of the convex surface to be low. Also, from the viewpoint of the sensitivity of magnetic sensors, it is preferable for the width of the convex surface to be small in order to provide more magnetoresistive elements. However, conventionally, it has been difficult to reduce the height of the convex surface while simultaneously reducing its width.

[0007] The above problem applies not only to magnetic sensors but to all sensors in general where the sensor element is formed on an inclined surface.

[0008] The present invention has been made in view of the above problems, and its object is to provide a sensor in which a functional layer of a sensor element is formed on an inclined convex surface, and the height of the convex surface can be reduced. [Means for solving the problem]

[0009] The sensor of the present invention is a sensor configured to detect a predetermined physical quantity. The sensor of the present invention comprises a substrate having an upper surface, a support member disposed on the substrate, and a sensor element configured to change its physical properties according to a predetermined physical quantity. The support member has a convex surface that protrudes away from the upper surface of the substrate and at least a portion of it is inclined with respect to the upper surface of the substrate. The sensor element includes a functional layer that constitutes at least a portion of the sensor element. The functional layer is disposed on the convex surface. The convex surface has an upper end furthest from the upper surface of the substrate and includes a curved portion that includes the upper end of the convex surface and is convex in the direction away from the upper surface of the substrate. The curved portion includes a first portion that includes the upper end of the convex surface and a second portion that is continuous with the first portion at a position away from the upper end of the convex surface. When the shape of the convex surface in a cross-section perpendicular to the top surface of the substrate is considered as a function Z whose variables are the position on a hypothetical straight line parallel to both the cross-section and the top surface of the substrate, the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first part is smaller than the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second part. [Effects of the Invention]

[0010] In the sensor of the present invention, the support member has a convex surface. The curved portion of the convex surface includes a first portion that includes the upper end of the convex surface and a second portion that is continuous with the first portion at a position away from the upper end of the convex surface. The average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first portion is smaller than the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second portion. As a result, according to the present invention, in a sensor in which the functional layer of the sensor element is formed on an inclined convex surface, the height of the convex surface can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing a magnetic sensor according to one embodiment of the present invention. [Figure 2] This is a functional block diagram showing the configuration of a magnetic sensor device including a magnetic sensor according to one embodiment of the present invention. [Figure 3] This is a circuit diagram showing the circuit configuration of the first detection circuit in one embodiment of the present invention. [Figure 4] This is a circuit diagram showing the circuit configuration of the second detection circuit in one embodiment of the present invention. [Figure 5] This is a plan view showing a part of the magnetic sensor according to one embodiment of the present invention. [Figure 6] This is a cross-sectional view showing a part of the magnetic sensor according to one embodiment of the present invention. [Figure 7] This is a side view showing the magnetoresistive element in one embodiment of the present invention. [Figure 8] This is a cross-sectional view showing a step in the manufacturing method of the magnetic sensor according to one embodiment of the present invention. [Figure 9] This is a cross-sectional view showing the step following the step shown in FIG. 8. [Figure 10] This is a cross-sectional view showing the step following the step shown in FIG. 9. [Figure 11] This is a cross-sectional view showing the step following the step shown in FIG. 10. [Figure 12] This is an explanatory diagram for explaining the shape of the support member in one embodiment of the present invention. [Figure 13] This is an explanatory diagram for explaining the shape of the convex surface in one embodiment of the present invention. [Figure 14] This is an explanatory diagram showing a graph of the function representing the shape of the convex surface in one embodiment of the present invention. [Figure 15] This is an explanatory diagram showing a graph of the first derivative of the function shown in FIG. 14. [Figure 16] This is an explanatory diagram showing a graph of the second derivative of the function shown in FIG. 14.

Embodiments for Carrying Out the Invention

[0012] The embodiments of the present invention described below relate to a sensor configured to detect a predetermined physical quantity. In an embodiment, the sensor includes a sensor element configured such that its physical properties change according to a predetermined physical quantity. For example, the predetermined physical quantity may be at least one of the direction and intensity of a target magnetic field that is the magnetic field of a detection target. In this case, the sensor element may be a magnetic detection element configured to detect at least one of the change in the direction and intensity of the target magnetic field. A sensor including a magnetic detection element is also called a magnetic sensor. The magnetic sensor is configured to detect at least one of the direction and intensity of the target magnetic field. Hereinafter, the embodiments will be described in detail by taking the case where the sensor is a magnetic sensor as an example.

[0013] First, referring to FIGS. 1 and 2, the configuration of a magnetic sensor according to an embodiment of the present invention will be described. FIG. 1 is a perspective view showing the magnetic sensor according to the present embodiment. FIG. 2 is a functional block diagram showing the configuration of a magnetic sensor device including the magnetic sensor according to the present embodiment. The magnetic sensor 1 according to the present embodiment corresponds to the "sensor" in the present invention.

[0014] As shown in FIG. 1, the magnetic sensor 1 has the form of a rectangular parallelepiped chip. The magnetic sensor 1 has an upper surface 1a and a lower surface located on opposite sides of each other, and four side surfaces connecting the upper surface 1a and the lower surface. Further, the magnetic sensor 1 has a plurality of electrode pads provided on the upper surface 1a.

[0015] Here, with reference to Figure 1, the reference coordinate system in this embodiment will be described. The reference coordinate system is a coordinate system based on the magnetic sensor 1 and is a Cartesian coordinate system defined by three axes. In the reference coordinate system, the X, Y, and Z directions are defined. The X, Y, and Z directions are orthogonal to each other. In this embodiment in particular, the Z direction is the direction perpendicular to the upper surface 1a of the magnetic sensor 1 and the direction from the lower surface of the magnetic sensor 1 toward the upper surface 1a. The direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction. The three axes that define the reference coordinate system are the axis parallel to the X direction, the axis parallel to the Y direction, and the axis parallel to the Z direction.

[0016] Hereafter, the position at the end of the Z-direction relative to the reference position will be referred to as "above," and the position opposite to the "above" position relative to the reference position will be referred to as "below." Furthermore, regarding the components of magnetic sensor 1, the surface located at the end in the Z-direction will be referred to as the "top surface," and the surface located at the end in the -Z-direction will be referred to as the "bottom surface." Also, the expression "when viewed from the Z-direction" means viewing the object from a position far away in the Z-direction.

[0017] As shown in Figure 2, the magnetic sensor 1 comprises a first detection circuit 20 and a second detection circuit 30. Each of the first and second detection circuits 20 and 30 includes a plurality of magnetic detection elements and is configured to detect a target magnetic field and generate at least one detection signal. In this embodiment, the plurality of magnetic detection elements are a plurality of magnetoresistive elements. Hereinafter, magnetoresistive elements will be referred to as MR elements.

[0018] Multiple detection signals generated by the first and second detection circuits 20 and 30 are processed by the processor 40. The magnetic sensor 1 and the processor 40 constitute the magnetic sensor device 100. The processor 40 is configured to generate a first detection value and a second detection value that correspond to the components of the magnetic field at a predetermined reference position in two different directions by processing the multiple detection signals generated by the first and second detection circuits 20 and 30. In particular, in this embodiment, the two different directions are one direction parallel to the XY plane and one direction parallel to the Z direction. The processor 40 is configured, for example, by an application-specific integrated circuit (ASIC).

[0019] The processor 40 may be included, for example, in a support that supports the magnetic sensor 1. This support has a plurality of electrode pads. The first and second detection circuits 20, 30 and the processor 40 are connected, for example, via a plurality of electrode pads of the magnetic sensor 1, a plurality of electrode pads of the support, and a plurality of bonding wires. If the plurality of electrode pads of the magnetic sensor 1 are provided on the upper surface 1a of the magnetic sensor 1, the magnetic sensor 1 may be mounted on the upper surface of the support in a orientation where the lower surface of the magnetic sensor 1 faces the upper surface of the support.

[0020] Next, the first and second detection circuits 20 and 30 will be described with reference to Figures 3 to 6. Figure 3 is a circuit diagram showing the circuit configuration of the first detection circuit 20. Figure 4 is a circuit diagram showing the circuit configuration of the second detection circuit 30. Figure 5 is a plan view showing a part of the magnetic sensor 1. Figure 6 is a cross-sectional view showing a part of the magnetic sensor 1.

[0021] Here, as shown in Figure 5, the U and V directions are defined as follows: The U direction is the direction of rotation from the X direction toward the -Y direction. The V direction is the direction of rotation from the Y direction toward the X direction. In this embodiment, the U direction is specifically defined as the direction of rotation by α from the X direction toward the -Y direction, and the V direction is defined as the direction of rotation by α from the Y direction toward the X direction. Note that α is an angle greater than 0° and less than 90°. In one example, α is 45°. Furthermore, the direction opposite to the U direction is defined as the -U direction, and the direction opposite to the V direction is defined as the -V direction.

[0022] Furthermore, as shown in Figure 6, the W1 and W2 directions are defined as follows: The W1 direction is the direction of rotation from the V direction toward the -Z direction. The W2 direction is the direction of rotation from the V direction toward the Z direction. In this embodiment, the W1 direction is specifically defined as the direction of rotation by β from the V direction toward the -Z direction, and the W2 direction is defined as the direction of rotation by β from the V direction toward the Z direction. Note that β is an angle greater than 0° and less than 90°. The direction opposite to the W1 direction is defined as the -W1 direction, and the direction opposite to the W2 direction is defined as the -W2 direction. The W1 and W2 directions are orthogonal to the U direction, respectively.

[0023] The first detection circuit 20 is configured to detect a component of the target magnetic field parallel to the W1 direction and to generate at least one first detection signal corresponding to this component. The second detection circuit 30 is configured to detect a component of the target magnetic field parallel to the W2 direction and to generate at least one second detection signal corresponding to this component.

[0024] As shown in Figure 3, the first detection circuit 20 includes a power supply terminal V2, a ground terminal G2, signal output terminals E21 and E22, a first resistor R21, a second resistor R22, a third resistor R23, and a fourth resistor R24. The multiple MR elements of the first detection circuit 20 constitute the first to fourth resistors R21, R22, R23, and R24.

[0025] The first resistor R21 is located between the power supply terminal V2 and the signal output terminal E21. The second resistor R22 is located between the signal output terminal E21 and the ground terminal G2. The third resistor R23 is located between the signal output terminal E22 and the ground terminal G2. The fourth resistor R24 ​​is located between the power supply terminal V2 and the signal output terminal E22.

[0026] As shown in Figure 4, the second detection circuit 30 includes a power supply terminal V3, a ground terminal G3, signal output terminals E31 and E32, a first resistor R31, a second resistor R32, a third resistor R33, and a fourth resistor R34. The multiple MR elements of the second detection circuit 30 constitute the first to fourth resistors R31, R32, R33, and R34.

[0027] The first resistor R31 is located between the power supply terminal V3 and the signal output terminal E31. The second resistor R32 is located between the signal output terminal E31 and the ground terminal G3. The third resistor R33 is located between the signal output terminal E32 and the ground terminal G3. The fourth resistor R34 is located between the power supply terminal V3 and the signal output terminal E32.

[0028] A predetermined voltage or current is applied to each of the power supply terminals V2 and V3. Each of the ground terminals G2 and G3 is connected to ground.

[0029] Hereinafter, the multiple MR elements of the first detection circuit 20 will be referred to as multiple first MR elements 50B, and the multiple MR elements of the second detection circuit 30 will be referred to as multiple second MR elements 50C. Since the first and second detection circuits 20 and 30 are components of the magnetic sensor 1, it can also be said that the magnetic sensor 1 includes multiple first MR elements 50B and multiple second MR elements 50C. Furthermore, any MR element will be denoted by the reference numeral 50.

[0030] Figure 7 is a side view of the MR element 50. The MR element 50 is a spin valve type MR element. The MR element 50 has a magnetization fixed layer 52 having magnetization with a fixed direction, a free layer 54 having magnetization whose direction can change according to the direction of the target magnetic field, and a gap layer 53 disposed between the magnetization fixed layer 52 and the free layer 54. The MR element 50 may be a TMR (tunnel magnetoresistance) element or a GMR (giant magnetoresistance) element. In a TMR element, the gap layer 53 is a tunnel barrier layer. In a GMR element, the gap layer 53 is a non-magnetic conductive layer. In the MR element 50, the resistance value changes according to the angle that the direction of magnetization of the free layer 54 makes with respect to the direction of magnetization of the magnetization fixed layer 52. The resistance value is at its minimum when this angle is 0° and at its maximum when the angle is 180°. In each MR element 50, the free layer 54 has shape anisotropy such that its easy magnetization axis direction is perpendicular to the magnetization direction of the fixed magnetization layer 52. As a means of setting the easy magnetization axis in a predetermined direction for the free layer 54, a magnet can be used to apply a bias magnetic field to the free layer 54.

[0031] The MR element 50 further includes an antiferromagnetic layer 51. The antiferromagnetic layer 51, magnetization fixed layer 52, gap layer 53, and free layer 54 are stacked in this order. The antiferromagnetic layer 51 is made of an antiferromagnetic material and creates exchange coupling with the magnetization fixed layer 52 to fix the magnetization direction of the magnetization fixed layer 52. The magnetization fixed layer 52 may be a so-called self-pinned fixed layer (Synthetic Ferri Pinned layer, SFP layer). The self-pinned fixed layer has a stacked ferri structure in which a ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer are stacked, and the two ferromagnetic layers are antiferromagnetically coupled. If the magnetization fixed layer 52 is a self-pinned fixed layer, the antiferromagnetic layer 51 may be omitted.

[0032] Note that the arrangement of layers 51-54 in the MR element 50 may be reversed vertically from the arrangement shown in Figure 7.

[0033] In Figures 3 and 4, the filled arrows represent the direction of magnetization of the magnetization fixed layer 52 of the MR element 50. The open arrows represent the direction of magnetization of the free layer 54 of the MR element 50 when no target magnetic field is applied to the MR element 50.

[0034] In the example shown in Figure 3, the magnetization direction of the magnetization fixed layer 52 in each of the first and third resistive sections R21 and R23 is in the W1 direction. The magnetization direction of the magnetization fixed layer 52 in each of the second and fourth resistive sections R22 and R24 is in the -W1 direction. Furthermore, each free layer 54 of the multiple first MR elements 50B has shape anisotropy such that the easy magnetization axis direction is parallel to the U direction. The magnetization direction of the free layer 54 in each of the first and second resistive sections R21 and R22 is in the U direction when no target magnetic field is applied to the first MR element 50B. In the above case, the magnetization direction of the free layer 54 in each of the third and fourth resistive sections R23 and R24 is in the -U direction.

[0035] In the example shown in Figure 4, the magnetization direction of the magnetization fixed layer 52 in each of the first and third resistive sections R31 and R33 is in the W2 direction. The magnetization direction of the magnetization fixed layer 52 in each of the second and fourth resistive sections R32 and R34 is in the -W2 direction. Furthermore, each free layer 54 of the multiple second MR elements 50C has shape anisotropy such that the easy magnetization axis direction is parallel to the U direction. The magnetization direction of the free layer 54 in each of the first and second resistive sections R31 and R32 is in the U direction when no target magnetic field is applied to the second MR element 50C. In the above case, the magnetization direction of the free layer 54 in each of the third and fourth resistive sections R33 and R34 is in the -U direction.

[0036] The magnetic sensor 1 includes a magnetic field generator configured to apply a magnetic field in a predetermined direction to the free layer 54 of each of the multiple first MR elements 50B and multiple second MR elements 50C. In this embodiment, the magnetic field generator includes a coil 80 that applies a magnetic field in a predetermined direction to the free layer 54 of each of the multiple first MR elements 50B and multiple second MR elements 50C.

[0037] Furthermore, the direction of magnetization of the fixed magnetization layer 52 and the direction of the easy magnetization axis of the free layer 54 may be slightly deviated from the above-mentioned direction from the viewpoint of the accuracy of fabrication of the MR element 50. Also, the magnetization of the fixed magnetization layer 52 may be configured to include a magnetization component whose main component is the direction described above. In this case, the direction of magnetization of the fixed magnetization layer 52 will be the direction described above or approximately the direction described above.

[0038] The specific structure of the magnetic sensor 1 will be described in detail below with reference to Figures 5 and 6. Figure 6 shows a portion of the cross-section at the position indicated by line 6-6 in Figure 5.

[0039] The magnetic sensor 1 includes a substrate 301 having an upper surface 301a, insulating layers 302, 303, 304, 305, 306, 307, 308, 309, 310, a plurality of lower electrodes 61B, a plurality of lower electrodes 61C, a plurality of upper electrodes 62B, a plurality of upper electrodes 62C, a plurality of lower coil elements 81, and a plurality of upper coil elements 82. The upper surface 301a of the substrate 301 is assumed to be parallel to the XY plane. The Z direction is also a direction perpendicular to the upper surface 301a of the substrate 301. Note that a coil element is a part of the winding of a coil.

[0040] The insulating layer 302 is placed on the substrate 301. Multiple lower coil elements 81 are placed on the insulating layer 302. The insulating layer 303 is placed on the insulating layer 302 around the multiple lower coil elements 81. Insulating layers 304, 305, and 306 are laminated in this order on the multiple lower coil elements 81 and insulating layer 303.

[0041] Multiple lower electrodes 61B and multiple lower electrodes 61C are arranged on an insulating layer 306. An insulating layer 307 is arranged on the insulating layer 306 around the multiple lower electrodes 61B and multiple lower electrodes 61C. Multiple first MR elements 50B are arranged on multiple lower electrodes 61B. Multiple second MR elements 50C are arranged on multiple lower electrodes 61C. An insulating layer 308 is arranged on the multiple lower electrodes 61B, multiple lower electrodes 61C and insulating layer 307 around the multiple first MR elements 50B and multiple second MR elements 50C. Multiple upper electrodes 62B are arranged on multiple first MR elements 50B and insulating layer 308. Multiple upper electrodes 62C are arranged on multiple second MR elements 50C and insulating layer 308. An insulating layer 309 is arranged on the insulating layer 308 around multiple upper electrodes 62B and multiple upper electrodes 62C.

[0042] The insulating layer 310 is positioned on a plurality of upper electrodes 62B, a plurality of upper electrodes 62C, and an insulating layer 309. A plurality of upper coil elements 82 are positioned on the insulating layer 310. The magnetic sensor 1 may further include an insulating layer (not shown) covering the plurality of upper coil elements 82 and the insulating layer 310.

[0043] The magnetic sensor 1 includes a support member that supports a plurality of first MR elements 50B and a plurality of second MR elements 50C. The support member has at least one inclined surface that is inclined with respect to the upper surface 301a of the substrate 301. In this embodiment in particular, the support member is composed of an insulating layer 305. Figure 5 shows the insulating layer 305, the plurality of first MR elements 50B, the plurality of second MR elements 50C, and the plurality of upper coil elements 82 among the components of the magnetic sensor 1.

[0044] The insulating layer 305 has a plurality of convex surfaces 305c that protrude in the direction away from the upper surface 301a of the substrate 301 (Z direction). Each of the plurality of convex surfaces 305c extends in a direction parallel to the U direction. The overall shape of the convex surface 305c is a semi-cylindrical curved surface formed by moving the curved shape (arch shape) of the convex surface 305c shown in Figure 6 along a direction parallel to the U direction. Furthermore, the plurality of convex surfaces 305c are arranged at predetermined intervals in a direction parallel to the V direction.

[0045] Each of the multiple convex surfaces 305c has an upper end that is furthest from the upper surface 301a of the substrate 301. In this embodiment, the upper end of each of the multiple convex surfaces 305c is assumed to extend in a direction parallel to the U direction. Now, let us focus on any one of the multiple convex surfaces 305c. The convex surface 305c includes a first inclined surface 305a and a second inclined surface 305b. The first inclined surface 305a is the surface of the convex surface 305c that is on the V direction side of the upper end of the convex surface 305c. The second inclined surface 305b is the surface of the convex surface 305c that is on the -V direction side of the upper end of the convex surface 305c. In Figure 5, the boundary between the first inclined surface 305a and the second inclined surface 305b is shown by a dotted line.

[0046] The upper end of the convex surface 305c may be the boundary between the first inclined surface 305a and the second inclined surface 305b. In this case, the dotted line shown in Figure 5 indicates the upper end of the convex surface 305c.

[0047] The upper surface 301a of the substrate 301 is parallel to the XY plane. The first inclined surface 305a and the second inclined surface 305b are each inclined with respect to the upper surface 301a of the substrate 301, i.e., the XY plane. In a cross section perpendicular to the upper surface 301a of the substrate 301, the distance between the first inclined surface 305a and the second inclined surface 305b decreases as the distance from the upper surface 301a of the substrate 301 increases.

[0048] In this embodiment, since there are multiple convex surfaces 305c, there are also multiple first inclined surfaces 305a and multiple second inclined surfaces 305b. The insulating layer 305 has multiple first inclined surfaces 305a and multiple second inclined surfaces 305b.

[0049] The insulating layer 305 further has flat surfaces 305d surrounding the plurality of convex surfaces 305c. The flat surfaces 305d are parallel to the upper surface 301a of the substrate 301. Each of the plurality of convex surfaces 305c protrudes from the flat surfaces 305d in the Z direction. In this embodiment, the plurality of convex surfaces 305c are arranged with a predetermined interval between them. Therefore, a flat surface 305d exists between two adjacent convex surfaces 305c in the V direction.

[0050] The insulating layer 305 includes a plurality of protrusions, each projecting in the Z direction, and flat portions surrounding the plurality of protrusions. Each of the plurality of protrusions extends in a direction parallel to the U direction and has a convex surface 305c. The plurality of protrusions are arranged at predetermined intervals in a direction parallel to the V direction. The thickness of the flat portions (dimension in the Z direction) is substantially constant.

[0051] The insulating layer 304 has a substantially constant thickness (dimension in the Z direction) and is formed along the lower surface of the insulating layer 305. The insulating layer 306 has a substantially constant thickness (dimension in the Z direction) and is formed along the upper surface of the insulating layer 305.

[0052] In this embodiment, the insulating layer 305 includes a first layer 3051 disposed on top of the insulating layer 304 and a second layer 3052 disposed on top of the first layer 3051. The second layer 3052 includes a plurality of portions that are separated from each other. The insulating layer 306 is disposed on the portion of the upper surface of the first layer 3051 where the second layer 3052 is not disposed and on top of the upper surface of the second layer 3052. Each of the plurality of first inclined surfaces 305a and the plurality of second inclined surfaces 305b is formed across the first layer 3051 and the second layer 3052.

[0053] Multiple lower electrodes 61B are arranged on multiple first inclined surfaces 305a. Multiple lower electrodes 61C are arranged on multiple second inclined surfaces 305b. As described above, since each of the first inclined surface 305a and the second inclined surface 305b is inclined with respect to the upper surface 301a of the substrate 301, i.e., the XY plane, the upper surfaces of each of the multiple lower electrodes 61B and each of the multiple lower electrodes 61C are also inclined with respect to the XY plane. Therefore, it can be said that the multiple first MR elements 50B and the multiple second MR elements 50C are arranged on inclined surfaces that are inclined with respect to the XY plane. The insulating layer 305 is a member for supporting each of the multiple first MR elements 50B and the multiple second MR elements 50C so that they are inclined with respect to the XY plane.

[0054] In this embodiment, the first inclined surface 305a is a curved surface. Therefore, the first MR element 50B curves along the curved surface (first inclined surface 305a). In this embodiment, for convenience, the direction of magnetization of the magnetization fixed layer 52 of the first MR element 50B is defined as a linear direction as described above. The W1 direction and -W1 direction, which are the directions of magnetization of the magnetization fixed layer 52 of the first MR element 50B, are also the directions in which the tangents that are in contact with the portion of the first inclined surface 305a near the first MR element 50B extend.

[0055] Similarly, in this embodiment, the second inclined surface 305b is a curved surface. Therefore, the second MR element 50C curves along the curved surface (second inclined surface 305b). In this embodiment, for convenience, the direction of magnetization of the magnetization fixed layer 52 of the second MR element 50C is defined as a linear direction as described above. The W2 direction and -W2 direction, which are the directions of magnetization of the magnetization fixed layer 52 of the second MR element 50C, are also the directions in which the tangents that are in contact with the portion of the second inclined surface 305b near the second MR element 50C extend.

[0056] As shown in Figure 5, the multiple first MR elements 50B are arranged so that multiple elements are lined up in the U direction and multiple elements are lined up in the V direction. Multiple first MR elements 50B are lined up in a row on one first inclined surface 305a. Similarly, the multiple second MR elements 50C are arranged so that multiple elements are lined up in the U direction and multiple elements are lined up in the V direction. Multiple second MR elements 50C are lined up in a row on one second inclined surface 305b. In this embodiment, the rows of multiple first MR elements 50B and rows of multiple second MR elements 50C are arranged alternately in a direction parallel to the V direction.

[0057] Furthermore, an adjacent first MR element 50B and a second MR element 50C may or may not be offset in a direction parallel to the U direction when viewed from the Z direction. Also, two first MR elements 50B adjacent to each other with one second MR element 50C in between may or may not be offset in a direction parallel to the U direction when viewed from the Z direction. Also, two second MR elements 50C adjacent to each other with one first MR element 50B in between may or may not be offset in a direction parallel to the U direction when viewed from the Z direction.

[0058] Multiple first MR elements 50B are connected in series by multiple lower electrodes 61B and multiple upper electrodes 62B. The connection method of the multiple first MR elements 50B will now be described in detail with reference to Figure 7. In Figure 7, reference numeral 61 indicates a lower electrode corresponding to any MR element 50, and reference numeral 62 indicates an upper electrode corresponding to any MR element 50. As shown in Figure 7, each lower electrode 61 has an elongated shape. A gap is formed between two adjacent lower electrodes 61 in the longitudinal direction. On the upper surface of the lower electrode 61, MR elements 50 are positioned near both ends in the longitudinal direction. Each upper electrode 62 also has an elongated shape and is positioned on two adjacent lower electrodes 61 in the longitudinal direction to electrically connect two adjacent MR elements 50.

[0059] Although not shown, one MR element 50 located at the end of a row of multiple MR elements 50 arranged in a single line is connected to another MR element 50 located at the end of an adjacent row of multiple MR elements 50 in a direction intersecting the longitudinal direction of the lower electrode 61. These two MR elements 50 are connected to each other by electrodes (not shown). The electrodes (not shown) may be electrodes connecting the lower surfaces of the two MR elements 50 or the upper surfaces of the two MR elements 50.

[0060] If the MR element 50 shown in Figure 7 is the first MR element 50B, then the lower electrode 61 shown in Figure 7 corresponds to the lower electrode 61B, and the upper electrode 62 shown in Figure 7 corresponds to the upper electrode 62B. In this case, the longitudinal direction of the lower electrode 61 is parallel to the U direction.

[0061] Similarly, multiple second MR elements 50C are connected in series by multiple lower electrodes 61C and multiple upper electrodes 62C. The explanation of the connection method for multiple first MR elements 50B described above also applies to the connection method for multiple second MR elements 50C. When the MR element 50 shown in Figure 7 is a second MR element 50C, the lower electrode 61 shown in Figure 7 corresponds to the lower electrode 61C, and the upper electrode 62 shown in Figure 7 corresponds to the upper electrode 62C. In this case, the longitudinal direction of the lower electrode 61 is parallel to the U direction.

[0062] In this embodiment, a laminated film including an antiferromagnetic layer 51, a magnetization-fixed layer 52, a gap layer 53, and a free layer 54 is described as the MR element 50. However, the MR element in this embodiment may also consist of this laminated film, a lower electrode 61, and an upper electrode 62. The laminated film includes a plurality of magnetic films. The lower electrode 61 is a non-magnetic metal layer disposed between the convex surface 305c and the plurality of magnetic films. The MR element may consist of a plurality of laminated films, a plurality of lower electrodes 61, and a plurality of upper electrodes 62.

[0063] Each of the multiple upper coil elements 82 extends in a direction parallel to the Y direction. Furthermore, the multiple upper coil elements 82 are arranged so as to be aligned in the X direction. In this embodiment in particular, when viewed from the Z direction, two upper coil elements 82 overlap each of the multiple first MR elements 50B and the multiple second MR elements 50C.

[0064] Each of the multiple lower coil elements 81 extends in a direction parallel to the Y direction. Furthermore, the multiple lower coil elements 81 are arranged so as to be aligned in the X direction. The shape and arrangement of the multiple lower coil elements 81 may be the same as or different from the shape and arrangement of the multiple upper coil elements 82. In the examples shown in Figures 5 and 6, the X-direction dimension of each of the multiple lower coil elements 81 is smaller than the X-direction dimension of each of the multiple upper coil elements 82. Also, the distance between two adjacent lower coil elements 81 in the X direction is smaller than the distance between two adjacent upper coil elements 82 in the X direction.

[0065] In the examples shown in Figures 5 and 6, the multiple lower coil elements 81 and the multiple upper coil elements 82 are electrically connected to form a coil 80 that applies a magnetic field parallel to the X direction to the free layers 54 of each of the multiple first MR elements 50B and the multiple second MR elements 50C. The coil 80 may also be configured to apply a magnetic field in the X direction to the free layers 54 of the first and second resistors R21, R22 of the first detection circuit 20 and the first and second resistors R31, R32 of the second detection circuit 30, and to apply a magnetic field in the -X direction to the free layers 54 of the third and fourth resistors R23, R24 of the first detection circuit 20 and the third and fourth resistors R33, R34 of the second detection circuit 30. The coil 80 may also be controlled by the processor 40.

[0066] Next, the first and second detection signals will be described. First, the first detection signal will be described with reference to Figure 3. When the intensity of the component of the target magnetic field parallel to the W1 direction changes, the resistance values ​​of each of the resistors R21 to R24 of the first detection circuit 20 change such that the resistance values ​​of resistors R21 and R23 increase while the resistance values ​​of resistors R22 and R24 decrease, or the resistance values ​​of resistors R21 and R23 decrease while the resistance values ​​of resistors R22 and R24 increase. As a result, the potentials of the signal output terminals E21 and E22 change. The first detection circuit 20 is configured to generate a signal corresponding to the potential of the signal output terminal E21 as the first detection signal S21, and a signal corresponding to the potential of the signal output terminal E22 as the first detection signal S22.

[0067] Next, the second detection signal will be described with reference to Figure 4. When the intensity of the component of the target magnetic field parallel to the W2 direction changes, the resistance values ​​of the resistors R31 to R34 of the second detection circuit 30 change such that the resistance values ​​of resistors R31 and R33 increase while the resistance values ​​of resistors R32 and R34 decrease, or the resistance values ​​of resistors R31 and R33 decrease while the resistance values ​​of resistors R32 and R34 increase. As a result, the potentials of the signal output terminals E31 and E32 change. The second detection circuit 30 is configured to generate a signal corresponding to the potential of the signal output terminal E31 as the second detection signal S31, and a signal corresponding to the potential of the signal output terminal E32 as the second detection signal S32.

[0068] Next, the operation of the processor 40 will be described. The processor 40 is configured to generate a first detection value and a second detection value based on the first detection signals S21, S22 and the second detection signals S31, S32. The first detection value is the detection value corresponding to the component of the target magnetic field in the direction parallel to the V direction. The second detection value is the detection value corresponding to the component of the target magnetic field in the direction parallel to the Z direction. Hereafter, the first detection value will be denoted by the symbol Sv and the second detection value will be denoted by the symbol Sz.

[0069] The processor 40 generates the first and second detection values ​​Sv and Sz, for example, as follows: First, the processor 40 generates value S1 by an operation that includes calculating the difference S21-S22 between the first detection signal S21 and the first detection signal S22, and then generates value S2 by an operation that includes calculating the difference S31-S32 between the second detection signal S31 and the second detection signal S32. Next, the processor 40 calculates values ​​S3 and S4 using the following equations (1) and (2).

[0070] S3 = (S2 + S1) / (2cosα) …(1) S4 = (S2 - S1) / (2sinα) …(2)

[0071] The first detected value Sv may be the value S3 itself, or it may be the value S3 to which predetermined corrections such as gain adjustment and offset adjustment have been applied. Similarly, the second detected value Sz may be the value S4 itself, or it may be the value S4 to which predetermined corrections such as gain adjustment and offset adjustment have been applied.

[0072] Next, a method for manufacturing the magnetic sensor 1 according to this embodiment will be described with reference to Figures 8 to 11. Figures 8 to 11 show the laminated structure in the manufacturing process of the magnetic sensor 1. In the manufacturing method of the magnetic sensor 1, first, as shown in Figure 8, an insulating layer 302 is formed on the substrate 301. Next, a plurality of lower coil elements 81, a connecting layer 83 made of a conductive material, and an insulating layer 303 are formed on the insulating layer 302. Next, an insulating layer 304 is formed on the plurality of lower coil elements 81, the connecting layer 83, and the insulating layer 303.

[0073] Figure 9 shows the following steps. In this step, first, the insulating layer 304 is selectively etched to form an opening in the insulating layer 304 that exposes the upper surface of the connecting layer 83. Next, a metal film 84 made of a conductive material is formed on the upper surface of the connecting layer 83. Next, a connecting layer 85 made of a conductive material is formed on the metal film 84. Next, the first layer 3051 of the insulating layer 305 is formed around the connecting layer 85.

[0074] Figure 10 shows the following steps. In this step, first, a metal film 86 made of a conductive material is formed on the upper surface of the connecting layer 85. Next, a second layer 3052 of the insulating layer 305 is formed on the metal film 86 and the first layer 3051 of the insulating layer 305.

[0075] Figure 11 shows the following process. In this process, the first layer 3051 and the second layer 3052 are etched so that a plurality of convex surfaces 305c are formed on the insulating layer 305. The plurality of convex surfaces 305c are formed, for example, by etching the first layer 3051, the second layer 3052, and the plurality of etching masks so that the plurality of etching masks are removed after forming a plurality of etching masks on the second layer 3052. The plurality of etching masks have shapes corresponding to the plurality of convex surfaces 305c. The portion of the first layer 3051 not covered by the plurality of etching masks becomes a flat surface 305d. In this etching, the metal film 86 functions as an etching stopper to protect the connecting layer 85.

[0076] The connecting layer 85 is a structure embedded in the first layer 3051. The connecting layer 85 has the end face, i.e., the upper surface, that is, the end face furthest from the upper surface 301a of the substrate 301. The end face (upper surface) of the connecting layer 85 is positioned substantially at the same location as the interface between the first layer 3051 and the second layer 3052 in a direction perpendicular to the upper surface 301a of the substrate 301, i.e., parallel to the Z direction.

[0077] The following describes the process after etching the first layer 3051 and the second layer 3052, with reference to Figure 6. First, an insulating layer 306 is formed on the first layer 3051 and the second layer 3052. Next, multiple lower electrodes 61B, multiple lower electrodes 61C, multiple first MR elements 50B, multiple second MR elements 50C, multiple upper electrodes 62B, multiple upper electrodes 62C, and insulating layers 307 to 309 are formed on the insulating layer 306.

[0078] Next, an insulating layer 310 is formed on the multiple upper electrodes 62B, multiple upper electrodes 62C, and insulating layer 309. Then, multiple upper coil elements 82 are formed on the insulating layer 310. This completes the magnetic sensor 1.

[0079] The connecting layers 83 and 85 may be used as connecting parts for connecting a plurality of lower coil elements 81 and a plurality of upper coil elements 82. In this case, for example, after forming the insulating layer 310 and before forming the plurality of upper coil elements 82, the insulating layers 306 to 310 may be selectively etched to form openings that expose the metal film 86, and a connecting layer (not shown) made of a conductive material may be formed within these openings. The plurality of upper coil elements 82 are formed to be connected to the connecting layer (not shown) after the connecting layer (not shown) has been formed.

[0080] Alternatively, the metal film 86 may be used as an arbitrary electrode pad (for example, an electrode pad for the coil 80). In this case, for example, a photoresist layer covering the metal film 86 may be formed after etching the first layer 3051 and the second layer 3052 and before forming the insulating layer 306. The photoresist layer is removed, for example, after forming the upper coil element 82.

[0081] Next, the structural features of the magnetic sensor 1 according to this embodiment will be described. The magnetic sensor 1 comprises a substrate 301 having an upper surface 301a, a support member disposed on the substrate 301, a first MR element 50B, and a second MR element 50C. In this embodiment, the insulating layer 305 corresponds to the support member. A plurality of lower coil elements 81 and insulating layers 302 to 304 are interposed between the substrate 301 and the insulating layer 305. The insulating layer 305 has a first inclined surface 305a and a second inclined surface 305b.

[0082] Each of the first and second MR elements 50B and 50C includes at least two magnetic films, namely a magnetized fixed layer 52 and a free layer 54. The two magnetic films of the first MR element 50B constitute a part (essential part) of the first MR element 50B. The two magnetic films of the second MR element 50C constitute a part (essential part) of the second MR element 50C. Hereinafter, the two magnetic films will be referred to as functional layers. The functional layer of the first MR element 50B is located on the first inclined surface 305a. The functional layer of the second MR element 50C is located on the second inclined surface 305b. The insulating layer 305 includes a first layer 3051 and a second layer 3052 located on the first layer 3051. Each of the first layer 3051 and the second layer 3052 is formed of an insulating material such as SiO2.

[0083] The features of the first inclined surface 305a, the second inclined surface 305b, the first layer 3051, and the second layer 3052 will be described in detail below with reference to Figure 12. Figure 12 is an explanatory diagram illustrating the shape of the support member, i.e., the insulating layer 305.

[0084] Each of the first inclined surface 305a and the second inclined surface 305b is formed across the first layer 3051 and the second layer 3052. Furthermore, the first inclined surface 305a and the second inclined surface 305b are oriented in different directions from each other. In one convex surface 305c, the first inclined surface 305a and the second inclined surface 305b may be symmetrical with respect to a virtual UZ plane perpendicular to the upper surface 301a of the substrate 301.

[0085] From the viewpoint of reducing the height of the magnetic sensor 1, it is preferable that the dimensions of the first inclined surface 305a and the second inclined surface 305b in a direction perpendicular to the upper surface 301a of the substrate 301, i.e., parallel to the Z direction, are within the range of 1.4 μm to 3.0 μm.

[0086] The first inclined surface 305a has a first edge 305a1 closest to the upper surface 301a of the substrate 301, and a second edge 305a2 furthest from the upper surface 301a of the substrate 301. The first edge 305a1 is located in the first layer 3051. The second edge 305a2 is located in the second layer 3052.

[0087] The second inclined surface 305b has a first edge 305b1 closest to the upper surface 301a of the substrate 301 and a second edge 305b2 furthest from the upper surface 301a of the substrate 301. The first edge 305b1 is located on the first layer 3051. The second edge 305b2 is located on the second layer 3052. In the example shown in Figure 12, the second edge 305b2 of the second inclined surface 305b coincides with the second edge 305a2 of the first inclined surface 305a.

[0088] The first layer 3051 has a lower end portion 3051a closest to the upper surface 301a of the substrate 301 and an upper end portion 3051b furthest from the upper surface 301a of the substrate 301. The second layer 3052 has a lower end portion 3052a closest to the upper surface 301a of the substrate 301 and an upper end portion 3052b furthest from the upper surface 301a of the substrate 301. The distance from the interface between the first layer 3051 and the second layer 3052 to the lower end portion 3051a of the first layer 3051 is smaller than the distance from the interface between the first layer 3051 and the second layer 3052 to the upper end portion 3052b of the second layer 3052.

[0089] The first edge 305a1 of the first inclined surface 305a is positioned between the lower end 3051a and the upper end 3051b of the first layer 3051 in a direction perpendicular to the upper surface 301a of the substrate 301, i.e., parallel to the Z direction. The first edge 305b1 of the second inclined surface 305b is positioned between the lower end 3051a and the upper end 3051b of the first layer 3051 in a direction parallel to the Z direction.

[0090] The functional layer of the first MR element 50B is arranged along the surface of the second layer 3052, but not along the surface of the first layer 3051. Similarly, the functional layer of the second MR element 50C is arranged along the surface of the second layer 3052, but not along the surface of the first layer 3051.

[0091] In this embodiment, the first inclined surface 305a is a generally smooth curved surface. There is no step at the boundary between the first layer 3051 and the second layer 3052 on the first inclined surface 305a. Similarly, in this embodiment, the second inclined surface 305b is a generally smooth curved surface. There is no step at the boundary between the first layer 3051 and the second layer 3052 on the second inclined surface 305b.

[0092] Next, with reference to Figure 13, the features of the convex surface 305c of the support member, i.e., the insulating layer 305, will be described. Figure 13 is an explanatory diagram for illustrating the shape of the convex surface 305c. The insulating layer 305 has a convex surface 305c. The convex surface 305c protrudes in a direction away from the upper surface 301a of the substrate 301. At least a portion of the convex surface 305c is inclined with respect to the upper surface 301a of the substrate 301. In this embodiment in particular, the convex surface 305c includes a first inclined surface 305a and a second inclined surface 305b.

[0093] The convex surface 305c has an upper end E1 that is furthest from the upper surface 301a of the substrate 301. The upper end E1 may coincide with the second edge 305a2 of the first inclined surface 305a and the second edge 305b2 of the second inclined surface 305b shown in Figure 12.

[0094] The dimensions of the convex surface 305c in the direction perpendicular to the upper surface 301a of the substrate 301, i.e., in the direction parallel to the Z direction, are the same as the dimensions of the first and second inclined surfaces 305a and 305b in the direction parallel to the Z direction. That is, the dimensions of the convex surface 305c in the direction parallel to the Z direction are preferably in the range of 1.4 μm to 3.0 μm. Furthermore, the dimensions of the convex surface 305c in the direction parallel to the V direction are preferably, for example, 3 μm to 16 μm.

[0095] The convex surface 305c includes a first curved surface portion 305c1 including the upper end E1, a second curved surface portion 305c2, and a third curved surface portion 305c3. The second curved surface portion 305c2 is continuous with the first curved surface portion 305c1 at a position on the V-direction side of the first curved surface portion 305c1, and is located between the first curved surface portion 305c1 and the upper surface 301a of the substrate 301 in a direction perpendicular to the upper surface 301a of the substrate 301. The third curved surface portion 305c3 is continuous with the first curved surface portion 305c1 at a position opposite to the second curved surface portion 305c2, i.e., at a position on the -V-direction side of the first curved surface portion 305c1, and is located between the first curved surface portion 305c1 and the upper surface 301a of the substrate 301 in a direction perpendicular to the upper surface 301a of the substrate 301. Furthermore, the second curved surface portion 305c2 and the third curved surface portion 305c3 are each continuous with the flat surface 305d.

[0096] The first curved surface portion 305c1 is a curved surface that is convex in the direction away from the upper surface 301a of the substrate 301. The second curved surface portion 305c2 and the third curved surface portion 305c3 are each curved surfaces that are convex in the direction approaching the upper surface 301a of the substrate 301.

[0097] Here, the cross-section perpendicular to the upper surface 301a of the substrate 301 and parallel to the VZ plane is called the reference cross-section. The first curved surface portion 305c1 can be approximated as a circular arc in the reference cross-section. In Figure 13, the radius of curvature of the first curved surface portion 305c1 in the reference cross-section, that is, the radius of curvature of the circular arc approximating the entire first curved surface portion 305c1, is indicated by the symbol R1. The radius of curvature R1 is preferably between 4.25 μm and 5.45 μm.

[0098] Similarly, the second curved surface portion 305c2 and the third curved surface portion 305c3 can each be approximated as a circular arc in the reference cross-section. In Figure 13, the radius of curvature of the second curved surface portion 305c2 in the reference cross-section, i.e., the radius of curvature of the circular arc approximating the second curved surface portion 305c2, is indicated by the symbol R2, and the radius of curvature of the third curved surface portion 305c3 in the reference cross-section, i.e., the radius of curvature of the circular arc approximating the third curved surface portion 305c3, is indicated by the symbol R3. Preferably, each of the radii of curvature R2 and R3 is smaller than the radius of curvature R1 and at least 0.3 μm.

[0099] Here, the shape of the convex surface 305c in the reference cross-section is considered as a function Z, with the position on a hypothetical straight line parallel to the reference cross-section and the upper surface 301a of the substrate 301 as the independent variable. The above hypothetical straight line is parallel to the V direction. Hereafter, the above hypothetical straight line will be called the V-axis, and the position on the V-axis will be represented by the symbol v. Function Z is a function with v as the independent variable. The value of function Z corresponds to the position of the convex surface 305c in the direction parallel to the Z direction. Figure 14 shows the graph of function Z. In Figure 14, the horizontal axis shows the position on the V-axis, and the vertical axis shows the value of function Z. Figure 14 essentially shows the shape of the convex surface 305c in the reference cross-section.

[0100] In Figure 14, the position on the V-axis corresponding to the upper end E1 of the convex surface 305c is defined as the origin (0 μm) on the horizontal axis. Positions on the V-direction side of the origin are represented by positive values, and positions on the -V-direction side of the origin are represented by negative values. Also, in Figure 14, the position of the flat surface 305d in the direction parallel to the Z-direction is defined as 0 μm.

[0101] Figure 15 shows the graph of the first derivative Z′(dZ / dv) obtained by differentiating the function Z once with respect to the variable v. In Figure 15, the horizontal axis represents the position on the V axis, and the vertical axis represents the value of the first derivative Z′. Figure 16 shows the second derivative Z″(dZ / dv) obtained by differentiating the function Z twice with respect to the variable v. 2 Z / dv 2 The graph of ) is shown. In Figure 15, the horizontal axis represents the position on the V-axis, and the vertical axis represents the value of the second derivative Z″.

[0102] The two positions where the second derivative Z'' is zero represent the positions on the V-axis corresponding to the boundary between the first surface portion 305c1 and the second surface portion 305c2, and the positions on the V-axis corresponding to the boundary between the first surface portion 305c1 and the third surface portion 305c3. Therefore, by referring to Figure 16, the respective positions of the first to third surface portions 305c1 to 305c3 can be determined. Figures 14 to 16 show the approximate ranges of the first to third surface portions 305c1 to 305c3.

[0103] As shown in Figure 16, at the position on the V-axis corresponding to the first surface portion 305c1, the value of the second derivative Z'' is less than or equal to 0. Furthermore, at the position on the V-axis corresponding to the second surface portion 305c2 and the position on the V-axis corresponding to the second surface portion 305c3, the value of the second derivative Z'' is positive.

[0104] Here, as shown in Figure 16, the first curved surface portion 305c1 is divided into a first portion c11, a second portion c12, and a third portion c13. The first portion c11 is the portion that includes the upper end E1 of the convex surface 305c. The second portion c12 is the portion that is located away from the upper end E1 of the convex surface 305c and is continuous with the first portion c11 on the V-direction side of the first portion c11. The third portion c13 is the portion that is located away from the upper end E1 of the convex surface 305c and is continuous with the first portion c11 on the -V-direction side of the first portion c11. The second portion c12 is located below (on the -Z-direction side) the first MR element 50B. The third portion c13 is located below (on the -Z-direction side) the second MR element 50C. The first and second MR elements 50B and 50C are not located above (on the Z-direction side) the first portion c11. Figure 16 shows the approximate ranges of each of the first to third parts c11 to c13.

[0105] The mean of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first part c11 is less than the mean of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second part c12. Similarly, the mean of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first part c11 is less than the mean of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the third part c13.

[0106] Furthermore, in this embodiment, as you approach the other end of the first curved surface portion 305c1 in the direction parallel to the V direction, from one end of the first curved surface portion 305c1 in the direction parallel to the V direction, the value of the first derivative Z' of the function Z corresponding to the first curved surface portion 305c1 decreases or increases. That is, as you approach the end of the first curved surface portion 305c1 in the direction of the V direction, from the end on the -V direction side of the first curved surface portion 305c1, the value of the first derivative Z' becomes smaller. Alternatively, as you approach the end of the first curved surface portion 305c1 in the direction of the V direction, from the end on the V direction side of the first curved surface portion 305c1, the value of the first derivative Z' becomes larger.

[0107] Next, the operation and effects of the magnetic sensor 1 according to this embodiment will be described. In this embodiment, the support member, i.e., the insulating layer 305, includes a first layer 3051 and a second layer 3052, and has first and second inclined surfaces 305a and 305b formed across the first layer 3051 and the second layer 3052, respectively. Now, consider embedding a structure made of a metal material into a support member of a comparative example which consists of only one insulating layer. In the support member of the comparative example, if an inclined surface is formed on the support member by etching, the structure protrudes significantly from the surface formed by etching due to the difference in etching rates. In this case, for example, the patterning of some electrodes and MR elements formed on the inclined surface becomes difficult due to the influence of the shadow of the structure.

[0108] In contrast, in this embodiment, for example, a structure can be embedded in the first layer 3051, while the structure is not embedded in the second layer 3052, and a first inclined surface 305a and a second inclined surface 305b can be formed on the insulating layer 305. As a result, according to this embodiment, the amount of protrusion of the structure can be suppressed compared to the support member of the comparative example.

[0109] The insulating material of the first layer 3051 and the insulating material of the second layer 3052 may be the same or different. Furthermore, the film deposition conditions for the first layer 3051 and the film deposition conditions for the second layer 3052 may be the same or different. For example, by making at least one of the insulating material and film deposition conditions different for the first layer 3051 and the second layer 3052, it becomes possible to make the shape of a portion of the convex surface 305c formed on the first layer 3051 and the shape of another portion of the convex surface 305c formed on the second layer 3052 different.

[0110] Furthermore, in this embodiment, the convex surface 305c includes first to third curved surface portions 305c1 to 305c3, each having the shape described above. If the second and third curved surface portions 305c2 and 305c3 were not present, the flat surface 305d and the first curved surface portion 305c1 would be discontinuous at the boundary between the flat surface 305d and the first curved surface portion 305c1. As a result, the surface of the insulating layer 305 would not be smooth. In contrast, in this embodiment, by including the second and third curved surface portions 305c2 and 305c3 in the convex surface 305c, the surface of the insulating layer 305 can be made smooth. Thus, according to this embodiment, it is possible to suppress the occurrence of cracks in the insulating layer 305 near the boundary between the convex surface 305c and the flat surface 305d.

[0111] As described above, the radius of curvature R1 of the first curved portion 305c1 of the convex surface 305c is different from the radius of curvature R2 of the second curved portion 305c2 of the convex surface 305c and the radius of curvature R3 of the third curved portion 305c3 of the convex surface 305c. At least a portion of the first curved portion 305c1 is formed in the second layer 3052. At least a portion of each of the second and third curved portions 305c2 and 305c3 is formed in the first layer 3051. According to this embodiment, for example, by making at least one of the insulating material and film formation conditions different in the first layer 3051 and the second layer 3052, it becomes possible to adjust the etching rate of the first layer 3051 and the etching rate of the second layer 3052 separately. As a result, according to this embodiment, it becomes easy to adjust the radii of curvature R2 and R3 to a preferred range while keeping the radius of curvature R1 within a preferred range.

[0112] In this embodiment, in particular, by setting the radii of curvature R2 and R3 within the aforementioned range, it is possible to suppress the occurrence of cracks in the insulating layer 305 near the boundary between the convex surface 305c and the flat surface 305d, compared to cases where the second and third curved surface portions 305c2 and 305c3 do not exist, or where the radius of curvature is small enough that the boundary between the convex surface 305c and the flat surface 305d can be considered discontinuous.

[0113] As can be seen from Figure 16, in this embodiment, the value of the second derivative Z'' of the function Z corresponding to the first curved surface portion 305c1 is not constant. Therefore, strictly speaking, the radius of curvature R1 changes depending on the position on the V-axis. In particular, in this embodiment, the average value of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first portion c11 of the first curved surface portion 305c1 is smaller than the average value of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second portion c12 of the first curved surface portion 305c1, and the average value of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the third portion c13 of the first curved surface portion 305c1. Therefore, in this embodiment, the radius of curvature R1 in the first portion c11 is larger than the radius of curvature R1 in the second portion c12 and the radius of curvature R1 in the third portion c13. As a result, according to this embodiment, the dimensions of the convex surface 305c in the direction parallel to the Z direction can be reduced, that is, the height of the convex surface 305c can be reduced, compared to the case where the radius of curvature R1 is constant regardless of its position on the V axis.

[0114] Furthermore, in this embodiment, the dimensions of the convex surface 305c in the direction parallel to the Z direction are preferably within the range of 1.4 μm to 3.0 μm. According to the exemplary embodiment, by setting the dimensions of the convex surface 305c to 1.4 μm or more, the inclination of the first inclined surface 305a and the second inclined surface 305b can be increased, thereby increasing the sensitivity of the magnetic sensor 1 to the component of the target magnetic field in the direction parallel to the Z direction. As a result, according to the exemplary embodiment, the second detected value Sz can be generated with high accuracy. Also, according to the exemplary embodiment, by setting the dimensions of the convex surface 305c to 3.0 μm or less, a photoresist mask consisting of a photoresist layer can be accurately formed on the first inclined surface 305a and the second inclined surface 305b during the manufacturing process of the magnetic sensor 1.

[0115] It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the magnetic detection element is not limited to an MR element, but may be an element that detects a magnetic field other than an MR element, such as a Hall element.

[0116] Furthermore, the support member of the present invention, i.e., the insulating layer 305, may consist of only one insulating layer. The description of the insulating layer 305 also applies to this single insulating layer, except for the descriptions relating to the first layer 3051 and the second layer 3052.

[0117] Furthermore, the support member of the present invention may be composed of an insulating layer 305 and an insulating layer 306. In this case, the support member has a plurality of convex surfaces and a flat surface. The plurality of convex surfaces and the flat surface are formed by the upper surface of the insulating layer 306. The upper surface of the insulating layer 306 is similar in shape to or approximately similar in shape to the upper surface of the insulating layer 305. Therefore, the plurality of convex surfaces formed by the upper surface of the insulating layer 306 are similar in shape to or approximately similar in shape to the plurality of convex surfaces 305c of the insulating layer 305. The description of the shape and arrangement of the plurality of convex surfaces 305c also applies to the plurality of convex surfaces formed by the upper surface of the insulating layer 306, except for the description relating to the first layer 3051 and the second layer 3052. Specifically, the description of the dimensions of the convex surfaces 305c, the description of the radius of curvature R1 to R3, and the description of the function Z, the first derivative Z' and the second derivative Z'' also apply to the plurality of convex surfaces formed by the upper surface of the insulating layer 306.

[0118] Furthermore, the magnetic sensor 1 may also include a third detection circuit configured to detect a component of the target magnetic field in a direction parallel to the XY plane and to generate at least one third detection signal corresponding to this component. In this case, the processor 40 may be configured to generate a detection value corresponding to the component of the target magnetic field in a direction parallel to the U direction based on at least one third detection signal. The third detection circuit may be integrated with the first and second detection circuits 20, 30, or it may be included in a separate chip from the first and second detection circuits 20, 30.

[0119] Furthermore, the sensor element of the present invention is not limited to a magnetic detection element, but may also be a sensor element configured to change its physical properties in accordance with a predetermined physical quantity. The predetermined physical quantity is not limited to a magnetic field, but may include quantities of any physical state that can be detected by the sensor element, such as an electric field, temperature, displacement, and force. The above description of the embodiment also applies to sensors other than magnetic sensors that are equipped with sensor elements other than a magnetic detection element, by replacing the magnetic detection element with a sensor element. In this case, the functional layer may be a part that constitutes at least a part of the sensor element and whose physical properties change in accordance with a predetermined physical quantity. Also, in this case, the metal layer may be any wiring layer.

[0120] As described above, the sensor of the present invention is a sensor configured to detect a predetermined physical quantity. The sensor of the present invention comprises a substrate having an upper surface, a support member disposed on the substrate, and a sensor element configured to change its physical properties according to a predetermined physical quantity. The support member has a convex surface that protrudes away from the upper surface of the substrate and at least a portion of it is inclined with respect to the upper surface of the substrate. The sensor element includes a functional layer that constitutes at least a portion of the sensor element. The functional layer is disposed on the convex surface. The convex surface has an upper end furthest from the upper surface of the substrate and includes a curved portion that includes the upper end of the convex surface and is convex in the direction away from the upper surface of the substrate. The curved portion includes a first portion that includes the upper end of the convex surface and a second portion that is continuous with the first portion at a position away from the upper end of the convex surface. When the shape of the convex surface in a cross-section perpendicular to the top surface of the substrate is considered as a function Z whose variables are the position on a hypothetical straight line parallel to both the cross-section and the top surface of the substrate, the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first part is smaller than the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second part.

[0121] In the sensor of the present invention, the functional layer may be located on top of the second portion.

[0122] Furthermore, in the sensor of the present invention, the value of the second derivative Z'' of the function Z corresponding to the curved surface portion may be 0 or less.

[0123] Furthermore, in the sensor of the present invention, the value of the first derivative Z' of the function Z corresponding to the curved portion may decrease or increase as one end of the curved portion approaches the other end of the curved portion in a predetermined direction parallel to the upper surface of the substrate.

[0124] Furthermore, in the sensor of the present invention, the convex surface may further include another curved surface portion that is continuous with the second portion and located between the second portion and the upper surface of the substrate in a direction perpendicular to the upper surface of the substrate. The other curved surface portion may be a curved surface that is convex in the direction toward the upper surface of the substrate. The value of the second derivative Z'' of the function Z corresponding to the boundary between the curved surface portion and the other curved surface portion may be 0.

[0125] Furthermore, in the sensor of the present invention, the dimensions of the convex surface in the direction perpendicular to the upper surface of the substrate may be 1.4 μm or more and 3.0 μm or less.

[0126] Furthermore, in the sensor of the present invention, the predetermined physical quantity may be at least one of the direction and intensity of the target magnetic field. The sensor element may be a magnetic detection element configured to detect a change in at least one of the direction and intensity of the target magnetic field. The magnetic detection element may be a magnetoresistive element. The functional layer may include a plurality of magnetic films. The magnetoresistive element may further include a non-magnetic metal layer disposed between the convex surface and the plurality of magnetic films. [Explanation of symbols]

[0127] 1…Magnetic sensor, 20…First detection circuit, 30…Second detection circuit, 40…Processor, 50…MR element, 50B…First MR element, 50C…Second MR element, 51…Antiferromagnetic layer, 52…Magnification fixed layer, 53…Gap layer, 54…Free layer, 61,61B,61C…Lower electrode, 62,62B,62C…Upper electrode, 80…Coil, 81…Lower coil element, 82…Upper Part coil element, 100...magnetic sensor device, 301...substrate, 301a...top surface, 302~310...insulating layer, 305a...first inclined surface, 305b...second inclined surface, 305c...convex surface, 305c1...first curved surface portion, 305c2...second curved surface portion, 305c3...third curved surface portion, 305d...flat surface, c11...first portion, c12...second portion, c13...third portion.

Claims

1. A sensor configured to detect a predetermined physical quantity, A substrate having an upper surface, A support member placed on the substrate, The system includes a sensor element configured to change its physical properties according to a predetermined physical quantity, The support member protrudes in a direction away from the upper surface of the substrate and has a convex surface that is inclined with respect to the upper surface of the substrate, The sensor element includes a functional layer that constitutes at least a part of the sensor element, The functional layer is placed on the convex surface, The convex surface has an upper end that is furthest from the upper surface of the substrate, and includes a curved portion that is convex in the direction away from the upper surface of the substrate, The curved portion includes a first portion that includes the upper end of the convex surface, and a second portion that is continuous with the first portion at a position away from the upper end of the convex surface. When the shape of the convex surface in a cross section perpendicular to the upper surface of the substrate is considered as a function Z whose variables are the position on a virtual straight line parallel to the cross section and the upper surface of the substrate, the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the first part is smaller than the average of the absolute values ​​of the second derivative Z'' of the function Z corresponding to the second part. The maximum value of the second derivative Z'' of the function Z corresponding to the first part is a negative value. The maximum value of the second derivative Z'' of the function Z corresponding to the second part is 0. A sensor characterized in that the minimum value of the second derivative Z'' of the function Z corresponding to the second part is a negative value.

2. The sensor according to claim 1, characterized in that the functional layer is arranged on top of the second portion.

3. The sensor according to claim 1, characterized in that the value of the second derivative Z'' of the function Z corresponding to the curved surface portion is 0 or less.

4. The sensor according to claim 1, characterized in that the value of the first derivative Z' of the function Z corresponding to the curved portion decreases or increases as you approach the other end of the curved portion in a predetermined direction parallel to the upper surface of the substrate from one end of the curved portion in the predetermined direction.

5. The convex surface further includes another curved portion that is continuous with the second portion and located between the second portion and the upper surface of the substrate in a direction perpendicular to the upper surface of the substrate, The sensor according to claim 1, characterized in that the other curved portion is a curved surface that is convex in the direction approaching the upper surface of the substrate.

6. The sensor according to claim 5, characterized in that the value of the second derivative Z'' of the function Z corresponding to the boundary between the curved surface portion and the other curved surface portion is 0.

7. The sensor according to claim 1, characterized in that the dimensions of the convex surface in a direction perpendicular to the upper surface of the substrate are 1.4 μm or more and 3.0 μm or less.

8. The predetermined physical quantity is at least one of the direction and intensity of the target magnetic field. The sensor according to any one of claims 1 to 7, characterized in that the sensor element is a magnetic detection element configured to detect a change in at least one of the direction and intensity of the target magnetic field.

9. The magnetic detection element is a magnetoresistive element. The sensor according to claim 8, characterized in that the functional layer includes a plurality of magnetic films.

10. The sensor according to claim 9, wherein the magnetoresistive element further includes a non-magnetic metal layer disposed between the convex surface and the plurality of magnetic films.

Images