WO2021029113A1

WO2021029113A1 - Sensor, strain detection sensor, pressure sensor, and microphone

Info

Publication number: WO2021029113A1
Application number: PCT/JP2020/017025
Authority: WO
Inventors: 将司久保田; 淳一橋本
Original assignee: 株式会社村田製作所
Priority date: 2019-08-13
Filing date: 2020-04-20
Publication date: 2021-02-18

Abstract

A sensor (100) comprises a substrate having a bending area (4) and a plurality of magnetoresistive elements (10). A first magnetoresistive element (11), second magnetoresistive element (12), third magnetoresistive element (13), and fourth magnetoresistive element (14) included in the plurality of magnetoresistive elements (10) each comprise a free layer, reference layer, and tunnel barrier layer. In a state in which no external force is being applied to the bending area (4), the first magnetoresistive element (11), second magnetoresistive element (12), third magnetoresistive element (13), and fourth magnetoresistive element (14) are each such that an angle θ1 is 135° ± 5°; the first magnetoresistive element (11) and fourth magnetoresistive element (14) are such that an angle θ2 is 45° ± 5°; and the second magnetoresistive element (12) and third magnetoresistive element (13) are such that an angle θ3 is 225° ± 5°.

Description

Sensors, strain detection sensors, pressure sensors, and microphones

The present disclosure relates to a sensor in which a magnetoresistive element is arranged on a flexible substrate, and a strain detection sensor, a pressure sensor, and a microphone provided with the sensor.

Yoshihiko Fuji, Shiori Kaji, Michiko Hara, "Spin MEMS microphone using high-sensitivity distortion detection element applying spintronics technology", Toshiba Review 73, 44 (2018) (Non-Patent Document 1) uses MEMS processing technology A microphone equipped with the sensor that was used is disclosed. As the sensor, a capacitance type sensor and a strain detection type sensor are known.

Capacitance type sensor (capacitance type MEMS microphone) changes the capacitance by changing the distance between the diaphragm electrode and the back plate electrode by sound. Although the sensor has high sensitivity, there is a limit to the improvement of SNR (Signal to Noise Ratio) due to the influence of air viscosity between electrodes. In addition, the structure is complicated, and the detection accuracy is lowered by foreign matter.

On the other hand, the distortion detection type sensor detects the distortion generated on the diaphragm surface by sound. Compared with the capacitance type sensor, the sensor is less affected by air viscosity, has a simple structure and is easy to manufacture, and the detection sensitivity is less likely to be lowered by foreign matter. Since the sensitivity of conventional semiconductor strain gauges is low, a strain detection type sensor (spin MEMS microphone) using MEMS processing technology has been proposed as an effort for high sensitivity and wide band.

In this spin MEMS microphone, a tunnel magnetoresistive (TMR) sensor is integrated by spintronics technology on a diaphragm formed by MEMS technology.

When the diaphragm is deformed by an external force such as pressure, inertia, or sound and the strain is transmitted to the TMR sensor, the magnetization direction of the free layer changes due to the inverse magnetostrictive effect. As a result, a large resistance change occurs due to the tunnel magnetoresistive effect depending on the relative angle between the magnetization directions of the free layer and the reference layer, so that minute distortion can be detected with high sensitivity.

By using the large resistance change of TMR, the performance index gauge factor (GF = dR / R / dε), which indicates the resistance change rate with respect to strain, is 2500 times that of the metal strain gauge and 40 times that of the semiconductor strain gauge. Has been done. Utilizing this characteristic, a prototype spin MEMS microphone in which a TMR sensor is connected in series on a diaphragm fixed at the periphery has been prototyped, and the SNR is 57 dB, which is compared with the existing capacitive MEMS microphone (56 to 74 dB). Although it is a prototype, it has good characteristics.

Y. Fuji et al., "Highly sensitive spintronic strain-gauge sensor based on magnetic tunnel junction and its applications to MEMS microphone", 2018 IEEE International Electron Devices Meeting (IEDM) (Non-Patent Document 2), and Japanese Patent Application Laid-Open No. 2018-006769 In Japanese Patent Application Laid-Open No. 1 (Patent Document 1), in a spin MEMS microphone, an early stage of a free layer is described for the purpose of making an odd function of resistance change with respect to positive and negative strain (tensile / compressive), improving input dynamic range, and reducing hysteresis. A technique for applying a bias to a free layer so that the magnetization direction is 45 degrees or 135 degrees with respect to the magnetization direction of the reference layer is disclosed.

Japanese Unexamined Patent Publication No. 2015-06425 (Patent Document 2) discloses a technique for changing the magnetization fixing direction of the reference layer according to the arrangement location of the detection element on the diaphragm in the spin MEMS microphone.

Japanese Patent Application Laid-Open No. 2015-061070 (Patent Document 3) states that in a spin MEMS microphone, as a technique for integrating a bias function in a magnetoresistive element, a free layer is provided by a laminated structure of a bias magnetic layer / separation layer / free layer. A technique for biasing by an interlayer exchange bonding layer is disclosed. As a method for fixing the magnetization of the bias magnetic layer, a laminated structure of an antiferromagnetic layer / bias magnetic layer or an antiferromagnetic layer / ferromagnetic layer / magnetic coupling layer / bias magnetic layer is disclosed. Further, it is disclosed that a full bridge circuit is formed by using a plurality of magnetoresistive elements.

In R. Antos, Y. Otani and J. Shibata, "Magnetic vortex dynamics", J. Phys. Soc. A magnetoresistive element having a vortex structure is disclosed. The magnetic vortex structure is manifested on a ferromagnetic submicron scale disc. Its magnetic structure is determined by the competition of exchange energy, electrostatic anisotropy (shape anisotropy), Zeeman energy, and various magnetic anisotropy energies. In the hysteresis loop in the magnetoresistive element having a magnetic vortex structure, a linear region appears in a part of the magnetization curve.

According to K. Y. Guslienko, "Magnetic vortex state stability, reversal and dynamics in restricted geometries", Journal of Nanoscience and Nanotechnology 8, 2745 (2008) (Non-Patent Document 4), the static energy depends on the shape, and the disk It is disclosed that the magnetization structure can be controlled by the aspect ratio (disk film thickness / disk diameter).

When the disk aspect ratio is small, shape anisotropy becomes predominant in the in-plane direction, and an in-plane single magnetic domain structure is adopted. When the disk aspect ratio is large, the shape anisotropy in the vertical direction becomes predominant, and a single magnetic domain structure in the vertical direction is adopted. In those intermediate regions, a magnetic vortex structure is formed mainly due to the competition between exchange energy and static energy.

In M. Schneider, H. Hoffmann and J. Zweck, "Lorentz microscopy of circular ferromagnetic permalloy nanodisks", Appl. Phys. Lett. 77, 2909 (2000) (Non-Patent Document 5), the linear region of the magnetization curve is a disk. It is disclosed that it expands as the diameter decreases (increases the aspect ratio).

U.S. Patent Application Publication No. 2008/018886 (Patent Document 4) states that in a giant magnetoresistive (GMR) or tunnel magnetoresistive (TMR) sensor, in order to obtain a linear input magnetic field-resistance characteristic of odd function type. , A method using a magnetic vortex structure (vortex) has been proposed.

Specifically, a structure in which a magnetoresistive element including a laminated portion in which a reference layer, a barrier layer, and a free layer having a magnetic vortex structure are laminated in this order is sandwiched between a lower shield and an upper shield formed of a magnetically permeable material. Is disclosed. In the reference layer, the magnetization is fixed in the in-plane direction, and in the free layer, the magnetization is spiral.

Motoi Endo, Mikihiko Okane, Hiroshi Naganuma, Yasuo Ando, Ferromagnetic tunnel junction magnetic field sensor applying magnetic vortex structure, 39th Annual Meeting of the Magnetic Society of Japan 10pE-12, 277 (2015) (Non-Patent Document 6) , And T. Wurft, W. Raberg, K. Prugl, A. Satz, G. Reiss and H. Bruckl, The influence of edge inhomogeneities on vortex hysteresis curves in magnetic tunnel junctions, IEEE Transactions on 2017) (Non-Patent Document 7) also discloses a magnetic resistance element having a magnetic vortex structure.

U.S. Patent Application Publication No. 2017/0168122 (Patent Document 5) discloses that an exchange coupling bias is expressed by a laminated structure of a free layer having a magnetic vortex structure and an antiferromagnetic layer.

JP-A-2018-006769 Japanese Unexamined Patent Publication No. 2015-06425 JP-A-2015-061070 U.S. Patent Application Publication No. 2008/0188865 U.S. Patent Application Publication No. 2017/0168122

However, in the spin MEMS microphone in Non-Patent Document 1, although the TMR elements are connected in series on the diaphragm, it is not disclosed that the bridge circuit is formed by the TMR elements.

In Non-Patent Document 2 and Patent Document 1, as described above, a technique of applying a bias to the free layer so that the initial magnetization direction of the free layer is 45 degrees or 135 degrees with respect to the magnetization direction of the reference layer. Is disclosed. However, although the bias application direction is effective as a technique for increasing the sensitivity when the bridge circuit is not formed by the TMR element, it cannot be said to be optimal when the bridge circuit is formed by the TMR element.

In the above-mentioned Patent Document 2, as described above, it is disclosed that the magnetization fixing direction of the reference layer is changed according to the arrangement location of the detection element on the diaphragm. However, when the bridge circuit is composed of the detection elements, the optimum arrangement of the plurality of detection elements, the magnetization fixing direction of the reference layer, and the like are not disclosed.

As described above, Patent Document 3 discloses a technique of applying a bias magnetic field to the free layer by interlayer exchange bonding. However, in Patent Document 3, in order to improve the characteristics, there is room for improving the direction of the bias magnetic field, the direction of magnetization of the reference layer, and the like in relation to the individual arrangement of the plurality of magnetoresistive elements constituting the bridge circuit. ..

In addition, when the free layer is biased only by the interlayer exchange coupling, the bias strength is adjusted by designing the material and film thickness of the laminated structure. Therefore, it is difficult to form a laminate so that the bias strengths are different in the same wafer and in the bridge circuit.

As described above, the above-mentioned Patent Document 4, Non-Patent Document 6 and Non-Patent Document 7 disclose a magnetoresistive element having a magnetic vortex structure. However, the application of the magnetoresistive element to a sensor that detects distortion, pressure, inertia, sound, etc. is not disclosed.

Also in the above-mentioned Patent Document 5, as described above, as described above, a magnetoresistive element having a magnetic vortex structure is disclosed. However, the application of the magnetoresistive element to a sensor that detects distortion, pressure, inertia, sound, etc. is not disclosed.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is a sensor and distortion detection that include a full bridge circuit composed of a plurality of magnetoresistive elements and can improve sensitivity. To provide sensors, pressure sensors, and microphones.

The sensor based on the first aspect of the present disclosure includes a substrate having a deflection region and a plurality of magnetoresistive elements in which the center of gravity of each is arranged in the deflection region so as to be along the outer edge of the deflection region. The plurality of magnetoresistive elements include one or more first magnetoresistive elements and one or more second magnetoresistive elements constituting the first half-bridge circuit, and one or more members constituting the second half-bridge circuit. Includes a third magnetoresistive element and one or more fourth magnetoresistive elements. A full bridge circuit is composed of the first half bridge circuit and the second half bridge circuit. The first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element each have a free layer whose magnetization direction changes according to the deflection of the deflection region and magnetization. It has a reference layer having a fixed direction and a tunnel barrier layer arranged between the free layer and the reference layer. A bias magnetic field is applied to the free layer so that the magnetization direction faces a predetermined direction in a state where no external force is applied to the deflection region. Here, the state in which no external force is applied to the deflection region means a state in which strain, pressure, inertia, sound, or the like from the outside is not applied to the deflection region. In each of the first magnetic resistance element, the second magnetic resistance element, the third magnetic resistance element, and the fourth magnetic resistance element, the first magnetic resistance element, the second magnetic resistance element, and the third magnetism A straight line orthogonal to the shortest virtual straight line connecting the center of gravity of the resistance element and the fourth magnetic resistance element to the outer edge of the deflection region and passing through the center of gravity is set as a reference line, and the above reference line is used. When the intersection of the virtual straight line and the outer edge is viewed from the center of gravity in front of the center and the direction from the center of gravity to the right is used as the reference direction, the first magnetic resistance element, the second magnetic resistance element, and the third magnetic resistance In each of the element and the fourth magnetic resistance element, in a state where no external force is applied to the deflection region, the clockwise angle from the reference direction to the direction in which the magnetization of the free layer is directed by the bias magnetic field is , 135 degrees ± 5 degrees. In the first magnetoresistive element and the fourth magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 45 degrees ± 5 degrees. In the second magnetoresistive element and the third magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 225 degrees ± 5 degrees.

The sensor based on the second aspect of the present disclosure includes a substrate having a deflection region, and a plurality of magnetoresistive elements arranged in the deflection region so that their respective centers of gravity are arranged along the outer edge of the deflection region. The plurality of magnetoresistive elements include one or more first magnetoresistive elements and one or more second magnetoresistive elements constituting the first half-bridge circuit, and one or more members constituting the second half-bridge circuit. Includes a third magnetoresistive element and one or more fourth magnetoresistive elements. A full bridge circuit is composed of the first half bridge circuit and the second half bridge circuit. The first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element each have a free layer whose magnetization direction changes according to the deflection of the deflection region and magnetization. It has a reference layer having a fixed direction, and a tunnel barrier layer sandwiched between the free layer and the reference layer. A bias magnetic field is applied to the free layer so that the magnetization direction faces a predetermined direction in a state where the deflection region is not bent. In each of the first magnetic resistance element, the second magnetic resistance element, the third magnetic resistance element, and the fourth magnetic resistance element, the first magnetic resistance element, the second magnetic resistance element, and the third magnetism A straight line orthogonal to the shortest virtual straight line connecting the center of gravity of the resistance element and the fourth magnetic resistance element to the outer edge of the deflection region and passing through the center of gravity is set as a reference line, and the above reference line is used. When the intersection of the virtual straight line and the outer edge is viewed from the center of gravity in front of the center and the direction from the center of gravity to the right is used as the reference direction, the first magnetic resistance element, the second magnetic resistance element, and the third magnetic resistance In each of the element and the fourth magnetic resistance element, in a state where no external force is applied to the deflection region, the clockwise angle from the reference direction to the direction in which the magnetization of the free layer is directed by the bias magnetic field is , 135 degrees ± 5 degrees. In the first magnetoresistive element and the fourth magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 225 degrees ± 5 degrees. In the second magnetoresistive element and the third magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 45 degrees ± 5 degrees.

In the sensors based on the first aspect and the second aspect of the present disclosure, the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element are respectively. It is preferable to further have a bias layer for applying the bias magnetic field to the free layer and a separation layer arranged between the bias layer and the free layer.

In the sensor based on the first aspect and the second aspect of the present disclosure, the free layer may have a disk shape.

In the sensor based on the first aspect and the second aspect of the present disclosure, the free layer may have a magnetized vortex structure. In this case, the strength of the bias magnetic field applied to the free layer is preferably larger than the strength of the exchange coupling magnetic field acting between the free layer and the reference.

In the sensors based on the first aspect and the second aspect of the present disclosure, the disk diameter of the free layer in the first magnetoresistive element and the second magnetoresistive element, the third magnetoresistive element, and the second magnetic resistance element. 4 The disk diameter of the free layer in the magnetoresistive element may be different.

In the sensors based on the first aspect and the second aspect of the present disclosure, the sensitivity in the first magnetoresistive element and the second magnetoresistive element, and the sensitivity in the third magnetoresistive element and the fourth magnetoresistive element. The sensitivities may be different from each other.

In the sensor based on the first aspect and the second aspect of the present disclosure, the deflection area may be provided with one or more slits passing through the center of the deflection area. In this case, it is preferable that the deflection region is divided into a plurality of parts in the circumferential direction by the one or more slits.

In the sensor based on the first aspect and the second aspect of the present disclosure, the deflection region may include a first region and a second region separated from each other. In this case, it is preferable that the one or more first magnetoresistive elements and the one or more second magnetoresistive elements are arranged in the first region, and the one in the second region. It is preferable that the above-mentioned third magnetoresistive element and the above-mentioned one or more fourth magnetoresistive elements are arranged. Further, it is preferable that the resonance frequency of the first region and the resonance frequency of the second region are different from each other.

In the sensor based on the first aspect and the second aspect of the present disclosure, the deflection region may include a first region and a second region separated from each other. In this case, it is preferable that the one or more first magnetoresistive elements and the one or more second magnetoresistive elements are arranged in the first region, and the one in the second region. It is preferable that the above-mentioned third magnetoresistive element and the above-mentioned one or more fourth magnetoresistive elements are arranged. Further, it is preferable that the area of the first region and the area of the second region are different from each other.

In the sensor based on the first aspect and the second aspect of the present disclosure, when either the output from the first half-bridge circuit or the output from the second half-bridge circuit is saturated, the sensor is saturated. It is preferable to use the other of the output from the first half-bridge circuit and the output from the second half-bridge circuit.

The sensors based on the first and second aspects of the present disclosure include a first cancel magnetic field generator and a first cancel magnetic field generator that generate a cancel magnetic field that cancels the stress-induced anisotropy that appears when an external force is applied to the flexure region. The two canceling magnetic field generation unit, the first canceling magnetic field generation unit, and the current control unit for controlling the current flowing through the second canceling magnetic field generation unit may be further provided.

The distortion detection sensor of the present disclosure includes the above sensor.
The pressure sensor of the present disclosure includes the above sensor.

The microphone of the present disclosure includes the above sensor.

According to the present disclosure, a sensor, a strain detection sensor, a pressure sensor, and a microphone, which include a full bridge circuit composed of a plurality of magnetoresistive elements and can improve sensitivity, are provided.

It is the schematic sectional drawing which shows the sensor which concerns on Embodiment 1. FIG. It is a schematic plan view which shows the sensor which concerns on Embodiment 1. FIG. It is schematic cross-sectional view which shows the laminated structure of the magnetic resistance element which comprises the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the magnetization direction of a free layer and the magnetization direction of a reference layer in a non-deformed state in which a diaphragm portion is not deformed in the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 1st deformation state which the diaphragm part was deformed in the sensor which concerns on Embodiment 1. It is a figure which shows the direction of stress-induced anisotropy which occurs in the 1st deformation state shown in FIG. 5, and the direction of magnetization of a reference layer. It is a figure which shows the 2nd deformation state which the diaphragm part was deformed in the sensor which concerns on Embodiment 1. It is a figure which shows the direction of stress-induced anisotropy which occurs in the 2nd deformation state shown in FIG. 7, and the direction of magnetization of a reference layer. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of the diaphragm part, and the relative angle between the magnetization direction of a free layer and the magnetization direction of a reference layer in the sensor which concerns on Embodiment 1. FIG. FIG. 5 is a diagram showing the relationship between the relative angle shown in FIG. 9 and the resistance of a plurality of magnetoresistive element portions constituting the full bridge circuit in the sensor according to the first embodiment. It is a figure which shows the relationship between the deformation amount of the diaphragm part, and the resistance of a plurality of magnetoresistive element parts which form a full bridge circuit in the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of a diaphragm part, and the output voltage of a half-bridge circuit in the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of a diaphragm part, and the output voltage of a full bridge circuit in the sensor which concerns on Embodiment 1. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element, and the resistance of a plurality of magnetoresistive elements constituting a full bridge circuit, when the magnetization direction of a reference layer is shifted in the sensor which concerns on Embodiment 1. .. It is a figure which shows the relationship between the strain amount of a magnetoresistive element, and the output voltage of a full bridge circuit, when the magnetization direction of a reference layer is shifted in the sensor which concerns on Embodiment 1. In the sensor according to the first embodiment, the difference in the absolute value of the output of the full bridge circuit when the amount of distortion of the magnetoresistive element is + 0.02% and the amount of distortion of the magnetoresistive element is −0.02%. It is a figure which shows the relationship between the difference of an output range, and the deviation angle of a reference layer in the magnetization direction. It is a figure which shows the 1st process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 2nd process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 3rd process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 4th process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 5th process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 6th process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 7th process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the 8th process of the manufacturing process of the sensor which concerns on Embodiment 1. FIG. It is a figure which shows the magnetization direction of a free layer and the magnetization direction of a reference layer in a non-deformation state in which a diaphragm portion is not deformed in the sensor which concerns on a comparative form. It is a figure which shows the direction of stress-induced anisotropy which occurs in the 1st state which a diaphragm part is deformed, and the direction of magnetization of a reference layer in the sensor which concerns on the comparative form. It is a figure which shows the direction of stress-induced anisotropy which occurs in the 2nd state which a diaphragm part is deformed, and the direction of magnetization of a reference layer in the sensor which concerns on the comparative form. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of a diaphragm part, and the relative angle between the magnetization direction of a free layer and the magnetization direction of a reference layer in the sensor which concerns on the comparative form. It is a figure which shows the relationship between the relative angle shown in FIG. 28, and the resistance of a plurality of magnetoresistive element portions constituting a full bridge circuit in the sensor which concerns on the form of comparison. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of a diaphragm part, and the resistance of a plurality of magnetic resistance element parts constituting a full bridge circuit in the sensor which concerns on the comparative form. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by the deformation of a diaphragm part, and the output voltage of a half-bridge circuit in the sensor which concerns on the form of comparison. It is a figure which shows the relationship between the amount of distortion of a magnetoresistive element by deformation of a diaphragm part, and the output voltage of a full bridge circuit in the sensor which concerns on the form of comparison. It is a figure which shows the magnetization direction of a free layer and the magnetization direction of a reference layer in a non-deformation state in which a diaphragm portion is not deformed in the sensor which concerns on Embodiment 2. FIG. It is a figure which shows the direction of the stress-induced anisotropy which occurs in the 1st deformation state which a diaphragm part was deformed in the sensor which concerns on Embodiment 2, and the direction of magnetization of a reference layer. It is a figure which shows the direction of the stress-induced anisotropy which occurs in the 2nd deformation state in which the diaphragm part is deformed, and the direction of magnetization of a reference layer in the sensor which concerns on Embodiment 2. FIG. It is a figure which shows the magnetization direction of a free layer and the magnetization direction of a reference layer in a non-deformation state in which a diaphragm portion is not deformed in the sensor which concerns on Embodiment 3. FIG. It is a figure which shows the direction of the stress-induced anisotropy which occurs in the 1st deformation state which a diaphragm part was deformed in the sensor which concerns on Embodiment 3, and the direction of magnetization of a reference layer. It is a figure which shows the direction of the stress-induced anisotropy which occurs in the 2nd deformation state in which the diaphragm part is deformed in the sensor which concerns on Embodiment 3, and the direction of magnetization of a reference layer. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the fourth embodiment. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the fifth embodiment. It is a figure which shows the relationship between the frequency and the sensitivity in each of the 1st region and the 2nd region constituting the deflection region in the sensor which concerns on Embodiment 5. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the sixth embodiment. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the seventh embodiment. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the eighth embodiment. 9 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the ninth embodiment. 9 is a schematic perspective view showing a configuration of a magnetoresistive element and its surroundings in the sensor according to the ninth embodiment. 9 is a schematic cross-sectional view of the magnetoresistive element and its peripheral configuration according to the ninth embodiment. FIG. 5 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the tenth embodiment. It is a figure which shows the distortion detection sensor which concerns on Embodiment 10. It is a figure which shows the pressure sensor which concerns on Embodiment 11. It is a figure which shows the mobile information terminal provided with the microphone which concerns on Embodiment 12.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the figures. In the embodiments shown below, the same or common parts are designated by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a sensor according to the first embodiment. FIG. 2 is a schematic plan view showing the sensor according to the first embodiment. The sensor 100 according to the first embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the sensor 100 according to the first embodiment is a so-called MEMS type sensor, and includes a substrate 1 having a deflection region 4 and a plurality of magnetoresistive elements 10.

The substrate 1 includes a base portion 2 and a diaphragm portion 3. The base 2 is made of, for example, a silicon substrate. The diaphragm portion 3 is made of, for example, silicon, silicon oxide, silicon nitride, or the like.

The diaphragm portion 3 is supported on the base portion 2. The base portion 2 is formed with a cavity portion 5 that reaches the diaphragm portion 3 at a predetermined position. As a result, the diaphragm portion 3 of the portion corresponding to the cavity portion 5 can be bent, and the deflection region 4 is formed in the diaphragm portion 3.

The plurality of magnetoresistive elements 10 are arranged on the main surface of the diaphragm portion 3 located on the side opposite to the side where the base portion 2 is located. The plurality of magnetoresistive elements 10 are arranged in the deflection region 4 so that their respective centers of gravity are along the outer edge of the deflection region 4. The center of gravity defined here refers to the geometric center of a figure constituting the outer shape of the magnetoresistive element 10.

In the first embodiment, the deflection region 4 has a circular shape, whereby the plurality of magnetoresistive elements 10 are arranged side by side in an annular shape. The plurality of magnetoresistive elements 10 have a substantially square shape when viewed in a plan view.

The plurality of magnetoresistive elements 10 includes a plurality of first magnetoresistive elements 11, a plurality of second magnetoresistive elements 12, a plurality of third magnetoresistive elements 13, and a plurality of fourth magnetoresistive elements 14. A full bridge circuit is composed of a plurality of first magnetoresistive elements 11, a plurality of second magnetoresistive elements 12, a plurality of third magnetoresistive elements 13, and a plurality of fourth magnetoresistive elements 14.

In the first embodiment, a case where the number of the first magnetoresistive element 11, the second magnetoresistive element 12, the third magnetoresistive element 13, and the fourth magnetoresistive element 14 is a plurality is illustrated. These numbers may be singular.

The plurality of first magnetoresistive elements 11 constitute the first magnetoresistive element portion R1, and the plurality of second magnetoresistive elements 12 constitute the second magnetoresistive element portion R2. The first half-bridge circuit Hf1 is configured by connecting the first magnetoresistive element R1 and the second magnetoresistive sensor R2 in series.

The plurality of third magnetoresistive elements 13 constitute the third magnetoresistive element portion R3, and the plurality of fourth magnetoresistive elements 14 constitute the fourth magnetoresistive element portion R4. The second half bridge circuit Hf2 is configured by connecting the third magnetoresistive element portion R3 and the fourth magnetoresistive element portion R4 in series.

A full bridge circuit is configured by connecting the first half bridge circuit Hf1 and the second half bridge circuit Hf2 in parallel.

Specifically, one side of the first magnetoresistive element unit R1 is connected to the electrode unit P1 for applying the power supply voltage Vin. The other side of the first magnetoresistive element unit R1 is connected to the electrode unit P2 for extracting the output voltage V +.

One side of the second magnetoresistive element unit R2 is connected to the electrode unit P2 for extracting the output voltage V +. The other side of the second magnetoresistive element portion R2 is connected to the electrode portion P4 as a ground electrode.

One side of the third magnetoresistive element unit R3 is connected to the electrode unit P1 for applying the power supply voltage Vin. The other side of the third magnetoresistive element unit R3 is connected to the electrode unit P3 for taking out the output voltage V−.

One side of the fourth magnetoresistive element unit R4 is connected to the electrode unit P3 for taking out the output voltage V−. The other side of the fourth magnetoresistive element portion R4 is connected to the electrode portion P4 as a ground electrode.

The output voltage V + of the half bridge by the first magnetoresistive element R1 and the second magnetoresistive sensor R2 has a positive output property. The output voltage V− of the half bridge by the third magnetoresistive element unit R3 and the fourth magnetoresistive element unit R4 has a negative output property.

When the power supply voltage Vin is applied between the electrode portion P1 and the electrode portion P4, the output voltages V + and V- are taken out from the electrode portion P2 and the electrode portion P4 according to the magnitude of the external force acting on the deflection region 4. .. The output voltages V + and V- are differentially amplified via a differential amplifier (not shown).

FIG. 3 is a schematic cross-sectional view showing a laminated structure of magnetoresistive elements constituting the sensor according to the first embodiment. The laminated structure of the magnetoresistive element 10 will be described with reference to FIG. The laminated structure of the first magnetic resistance element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element is the same as the laminated structure of the magnetic resistance element 10 described here.

The magnetoresistive element 10 includes a lower electrode layer 20, a pinning layer 21, a pin layer 22, a magnetic coupling layer 23, a reference layer 24, a tunnel barrier layer 25, a free layer 26, a separation layer 27, a bias layer 28, and an upper electrode layer 29. including.

The lower electrode layer 20 functions as a seed layer for appropriately growing the crystals of the pinning layer 21. As the lower electrode layer 20, for example, a laminated film of Ru and Ta can be adopted. As the lower electrode layer 20, a single metal film made of another metal or alloy, or one in which a plurality of types of the above metal films are laminated can be adopted.

The pinning layer 21 is provided on the lower electrode layer 20. The pinning layer 21 is composed of an antiferromagnetic layer. As the pinning layer 21, for example, IrMn can be adopted. The pinning layer 21 may be an alloy containing Mn such as PtMn.

The pin layer 22 is provided on the pinning layer 21. The pin layer 22 is composed of a ferromagnetic layer. For example, CoFe can be adopted as the pin layer 22. The pin layer 22 may be CoFeB or the like. The magnetization of the pin layer 22 is fixed in a predetermined in-plane direction by the exchange coupling magnetic field acting from the pinning layer 21.

The magnetic coupling layer 23 is provided on the pin layer 22. The magnetic coupling layer 23 is arranged between the pin layer 22 and the reference layer 24, and causes an antiferromagnetic coupling between the pin layer 22 and the reference layer 24.

The magnetic coupling layer 23 is composed of a non-magnetic layer. As the magnetic coupling layer 23, for example, Ru can be adopted.

The reference layer 24 is provided on the magnetic coupling layer 23. The reference layer 24 is composed of a ferromagnetic layer. As the reference layer 24, for example, CoFeB can be adopted. The reference layer 24 may be CoFe or the like.

The pin layer 22, the magnetic coupling layer 23, and the reference layer 24 described above form a SAF structure. As a result, the magnetization direction of the reference layer 24 can be firmly fixed.

The tunnel barrier layer 25 is provided on the reference layer 24. The tunnel barrier layer 25 is arranged between the reference layer 24 and the free layer 26. The tunnel barrier layer 25 is composed of an insulating layer. As the tunnel barrier layer 25, for example, MgO can be adopted.

The free layer 26 is provided on the tunnel barrier layer 25. The free layer 26 is composed of a ferromagnetic layer. As the free layer 26, for example, a laminate of CoFeB and FeB can be adopted. In addition, in order to suppress the crystallization of FeB, a ferromagnetic amorphous layer such as CoFeTa may be provided between CoFeB and FeB and between FeB and the separation layer 27.

The separation layer 27 is provided on the free layer 26. The separation layer 27 is arranged between the free layer 26 and the bias layer 28. As the separation layer 27, Cu, Ru, Rh, Ir, V, Cr, Nb, Mo, Ta, W, Rr and the like showing an RKKY (Ruderman-Kittel-Kasuya-Yoshida) bond can be adopted. These can use positive magnetic coupling (ferromagnetism, parallel) and negative magnetic coupling (antiferromagnetism, antiparallel) properly according to the thickness of the separation layer 27. In addition, when Au, Ag, Pt, Pd, Ti, Zr, and Hf are used, a positive magnetic coupling is mainly obtained. When negative magnetic coupling is used, Ru, Rh, Ir can be used.

The bias layer 28 is provided on the separation layer 27. The bias layer 28 functions as a bias application unit that applies a bias magnetic field to the free layer 26. As the bias layer 28, a laminate of a ferromagnetic layer and an antiferromagnetic layer can be adopted. As the bias layer 28, for example, a laminate of CoFeB and IrMn can be adopted. CoFeB and IrMn are laminated from the separation layer 27 side in this order.

The bias layer 28 applies the exchange coupling magnetic field expressed by the ferromagnetic layer and the antiferromagnetic layer to the free layer 26 as a bias magnetic field. The strength of the bias magnetic field is greater than the interlayer exchange coupling strength from the reference layer 24.

Further, the antiferromagnetic layer on the reference layer side is provided so that the direction of the bias magnetic field applied to the free layer and the magnetization direction of the reference layer 24 (the direction of magnetization fixed in the reference layer 24) are different. , The blocking temperature of the antiferromagnetic layer on the bias layer 28 side is different. The blocking temperature of the antiferromagnetic layer on the reference layer side is higher than the blocking temperature of the antiferromagnetic layer on the bias layer 28 side. As a result, the sensor 100 can be manufactured stably in the process, and the reliability of the sensor 100 becomes good.

When the antiferromagnetic layer on the reference layer side and the antiferromagnetic layer on the bias layer 28 side are made of the same material, the antiferromagnetic layer on the reference layer side is the antiferromagnetic layer on the bias layer 28 side. By making it thicker than this, the blocking temperature of the antiferromagnetic layer on the reference layer side can be made higher than the blocking temperature of the antiferromagnetic layer on the bias layer 28 side.

As an example, the blocking temperature of PtMn is 310 ° C., and the blocking temperature of IrMn is 255 ° C. The antiferromagnetic layer on the reference layer side may be PtMn, and the antiferromagnetic layer on the bias layer side may be IrMn.

The upper electrode layer 29 is provided on the bias layer 28. As the upper electrode layer 29, for example, a laminated film of Ru and Ta can be adopted. As the upper electrode layer 29, a single metal film made of another metal or alloy, or a stack of a plurality of types of the above metal films can be adopted.

As described above, the case where the magnetoresistive element 10 according to the first embodiment is a Bottom-pinned type TMR element in which the reference layer 24 is arranged below the free layer 26 has been described as an example. It is not limited, and may be a Top-pinned type TMR element in which the reference layer 24 is arranged on the upper side of the free layer 26. Further, the magnetoresistive element 10 is not limited to the TMR element.

FIG. 4 is a diagram showing the direction of the magnetization direction of the free layer and the direction of magnetization of the reference layer in the non-deformed state in which the diaphragm portion is not deformed in the sensor according to the first embodiment. The arrow indicated by a black line in each magnetoresistive element 10 indicates the direction of the magnetic field applied to the free layer, and the arrow indicated by white in each magnetoresistive element 10 indicates the direction of magnetization of the reference layer. Is shown.

As shown in FIG. 4, in each of the first magnetic resistance element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element 14, the first magnetic resistance element 11 and the second magnetic resistance The straight line orthogonal to the virtual straight line VL1 connecting the center of gravity of each of the element 12, the third magnetic resistance element 13 and the fourth magnetic resistance element 14 to the outer edge of the deflection region 4 at the shortest distance and passing through the center of gravity is defined as the reference line BL1. To do.

Further, in each of the first magnetoresistive element 11, the second magnetoresistive element 12, the third magnetoresistive element 13, and the fourth magnetoresistive element 14, the virtual straight line VL1 and the outer edge of the deflection region 4 meet at the reference line BL1. The direction from the center of gravity to the right when the intersection is viewed from the center of gravity is defined as the reference direction.

When the diaphragm portion 3 is not deformed, that is, when no external force is applied to the deflection region 4, the first magnetoresistive element 11, the second magnetoresistive element 12, the third magnetoresistive element 13, and the fourth. In each of the magnetoresistive elements 14, the counterclockwise angle θ1 from the reference direction to the magnetization direction of the free layer (the direction in which the magnetization of the free layer is directed by the bias magnetic field) is 135 degrees ± 5 degrees.

In a state where no external force is applied to the deflection region 4, the counterclockwise angle θ2 from the reference direction to the magnetization direction of the reference layer 24 in the first magnetoresistive element 11 and the fourth magnetoresistive element 14 is 45. Degree ± 5 degrees.

In a state where no external force is applied to the deflection region 4, in the second magnetoresistive element 12 and the third magnetoresistive element 13, the counterclockwise angle θ3 from the reference direction to the magnetization direction of the reference layer 24 is 225. Degree ± 5 degrees.

By setting the angles θ1, θ2, and θ3 as described above, the absolute value of the output from the full bridge when the magnetoresistive element 10 is positively distorted and the magnetic resistance element 10 are negatively distorted, as described later. The difference from the absolute value of the output from the full bridge in the case can be 30% or less.

Further, the angle θ1 is preferably 135 degrees ± 3 degrees, the angle θ2 is preferably 45 degrees ± 3 degrees, and the angle θ3 is preferably 225 degrees ± 3 degrees. By setting the angles θ1, θ2, and θ3 as described above, the absolute value of the output from the full bridge when the magnetoresistive element 10 is positively distorted and the full bridge when the magnetoresistive element 10 is negatively distorted The difference from the absolute value of the output of is 20% or less.

Further, the angle θ1 is preferably 135 degrees ± 1.5 degrees, the angle θ2 is preferably 45 degrees ± 1.5 degrees, and the angle θ3 is 225 degrees ± 1.5 degrees. Is more preferable. By setting the angles θ1, θ2, and θ3 as described above, the absolute value of the output from the full bridge when the magnetoresistive element 10 is positively distorted and the full bridge when the magnetoresistive element 10 is negatively distorted The difference from the absolute value of the output of is 10% or less.

It is most preferable that the angle θ1 is 135 degrees, the angle θ2 is 45 degrees, and the angle θ3 is 225 degrees. In this case, the difference between the absolute value of the output from the full bridge when the magnetoresistive element 10 is positively distorted and the absolute value of the output from the full bridge when the magnetoresistive element 10 is negatively distorted is omitted. It can be 0%.

FIG. 5 is a diagram showing a first deformed state in which the diaphragm portion is deformed in the sensor according to the first embodiment.

As shown in FIG. 5, in the first deformation state of the diaphragm portion 3, the deflection region 4 of the diaphragm portion 3 is deformed so as to be convex toward the base portion 2. At this time, tensile stress acts on the magnetoresistive element 10.

FIG. 6 is a diagram showing the direction of stress-induced anisotropy generated in the first deformation state shown in FIG. 5 and the direction of magnetization of the reference layer. In FIG. 6, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 6 shows a case where the magnetostrictive constant is positive.

As shown by the black arrow in FIG. 6, the tensile stress acts along the radial direction of the deflection region 4. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to extend in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy develops toward the radial outer side of the deflection region 4. The direction of stress-induced anisotropy is parallel to the virtual straight line VL1 that connects the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 at the shortest distance, as shown by the black arrow shown in the magnetoresistive element 10 of FIG. ..

Specifically, in the first state, in the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ4 from the reference direction to the direction of stress-induced anisotropy is approximately 90 degrees. Become.

In the first state, the counterclockwise angle θ5 from the reference direction to the direction of stress-induced anisotropy is approximately 90 degrees also in the second magnetoresistive element 12 and the third magnetoresistive element 13.

FIG. 7 is a diagram showing a second deformed state in which the diaphragm portion is deformed in the sensor according to the first embodiment.

As shown in FIG. 7, in the second deformation state of the diaphragm portion 3, the deflection region 4 of the diaphragm portion 3 is deformed so as to be convex toward the side opposite to the side where the base portion 2 is located. At this time, compressive stress acts on the magnetoresistive element 10.

FIG. 8 is a diagram showing the direction of stress-induced anisotropy generated in the second deformation state shown in FIG. 7 and the direction of magnetization of the reference layer. In FIG. 8, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 8 shows a case where the magnetostrictive constant is positive.

As shown by the black arrow in FIG. 8, the compressive stress acts along the radial direction of the deflection region 4. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to contract in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy appears toward the tangential direction of the outer edge of the deflection region 4. The direction of stress-induced anisotropy is orthogonal to the virtual straight line VL1 that connects the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 at the shortest distance, as shown by the black arrow shown in the magnetoresistive element 10 of FIG. That is, the direction of stress-induced anisotropy is parallel to the reference line BL1.

Specifically, in the second state, in the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ4 from the reference direction to the direction of stress-induced anisotropy is approximately 180 degrees. It becomes.

In the second state, the counterclockwise angle θ5 from the reference direction to the stress-induced anisotropy direction is approximately 180 degrees also in the second magnetoresistive element 12 and the third magnetoresistive element 13.

As described above, when the magnetization direction of the free layer changes according to the strength of the stress-induced anisotropy, the relative angle between the reference layer 24 and the magnetization direction of the free layer changes. As a result, the resistance of the first magnetic resistance element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element 14, and by extension, the first magnetic resistance element R1 and the second magnetic resistance element The resistances of R2, the third magnetoresistive element R3, and the fourth magnetoresistive element R4 change. As a result, the output from the full bridge circuit changes.

FIG. 9 is a diagram showing the relationship between the amount of deformation of the diaphragm portion and the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer in the sensor according to the first embodiment.

As shown in FIG. 9, in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 (the first magnetoresistive element 11 and the fourth magnetoresistive element 14), the magnetic resistance element 10 is compressed from the non-deformed state. As a result, the relative angle between the magnetizing direction of the free layer and the magnetizing direction of the reference layer changes from 90 degrees to approach 130 degrees. Further, in the first magnetoresistive element R1 and the fourth magnetoresistive sensor R4, as the magnetoresistive element 10 is pulled from the non-deformed state, the magnetization direction of the free layer and the magnetization direction of the reference layer are relative to each other. The angle changes from 90 degrees to approaching approximately 50 degrees.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (the second magnetoresistive element 12 and the third magnetoresistive element 13), as the magnetic resistance element 10 is compressed from the non-deformed state, the free layer becomes The relative angle between the magnetizing direction and the magnetizing direction of the reference layer changes from 90 degrees to approach about 50 degrees. Further, in the second magnetoresistive element R2 and the third magnetoresistive sensor R3, as the magnetoresistive element 10 is pulled from the non-deformed state, the magnetization direction of the free layer and the magnetization direction of the reference layer are relative to each other. The angle changes from 90 degrees to approach approximately 130 degrees.

FIG. 10 is a diagram showing the relationship between the relative angle shown in FIG. 9 and the resistance of a plurality of magnetoresistive element portions constituting the full bridge circuit in the sensor according to the first embodiment.

As shown in FIG. 10, as the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer increases, the first magnetoresistive element R1, the second magnetoresistive element R2, and the third magnetoresistive element The resistance increases in each of the portion R3 and the fourth magnetoresistive element portion R4. The changes in the resistances of the first magnetoresistive element R1, the second magnetoresistive sensor R2, the third magnetoresistive element R3, and the fourth magnetoresistive element R4 are substantially the same.

FIG. 11 is a diagram showing the relationship between the amount of deformation of the diaphragm portion and the resistance of a plurality of magnetoresistive element portions constituting the full bridge circuit in the sensor according to the first embodiment.

As shown in FIG. 11, in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 (the first magnetoresistive element 11 and the fourth magnetoresistive element 14), the magnetoresistive element 10 is compressed from the non-deformed state. As it is done, the resistance changes from about 0.052 kΩ to approach about 0.08 kΩ. Further, in the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4, as the magnetoresistive element 10 is pulled from the non-deformed state, the resistance decreases from about 0.052 kΩ to about 0.04 kΩ. It changes to get closer.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (second magnetoresistive element 12 and third magnetoresistive element 13), as the magnetoresistive element 10 is compressed from the non-deformed state, the resistance is increased. It decreases from about 0.052 kΩ and changes to approach about 0.04 kΩ. Further, in the second magnetoresistive element portion R2 and the third magnetoresistive element portion R3, as the magnetoresistive element 10 is pulled from the non-deformed state, the resistance increases from approximately 0.042 kΩ to approximately 0.08 kΩ. It changes to get closer. In the example shown here, the design value of the resistor is 0.052 kΩ, but the value is not limited to this value, and the resistance value may be increased according to the required current consumption.

FIG. 12 is a diagram showing the relationship between the amount of deformation of the diaphragm portion and the output voltage of the half-bridge circuit in the sensor according to the first embodiment.

As shown in FIG. 12, in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 (the first magnetoresistive element 11 and the fourth magnetoresistive element 14), the magnetoresistive element 10 is compressed from the non-deformed state. As a result, the output of the first half-bridge circuit Hf1 changes from about 1.5V to approaching about 2.0V. Further, in the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4, the output of the first half bridge circuit Hf1 decreases from about 1.5 V as the magnetoresistive element 10 is pulled from the non-deformed state. Then, it changes so as to approach about 1.0 V.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (the second magnetoresistive element 12 and the third magnetoresistive element 13), the second half as the magnetoresistive element 10 is compressed from the non-deformed state. The output of the bridge circuit Hf2 decreases from about 1.5V and changes to approach about 1.0V. Further, in the second magnetoresistive element portion R2 and the third magnetoresistive element portion R3, the output of the second half bridge circuit Hf2 increases from about 1.5 V as the magnetoresistive element 10 is pulled from the non-deformed state. Then, it changes so as to approach about 2.0V.

FIG. 13 is a diagram showing the relationship between the amount of deformation of the diaphragm portion and the output voltage of the full bridge circuit in the sensor according to the first embodiment.

As shown in FIG. 13, the output voltage of the full bridge circuit increases from 0 mV as the magnetoresistive element 10 is compressed from the non-deformed state, and changes so as to approach approximately 900 mV. Further, the output voltage of the full bridge circuit decreases from 0 mV as the magnetoresistive element 10 is pulled from the non-deformed state, and changes so as to approach approximately −1000 mV.

Here, as described above, by setting the angles θ1, θ2, and θ3 in the above range in a state where no external force is applied to the deflection region 4, the first magnetoresistive element unit R1 and the first magnetic resistance element unit R1 and the first 4. The resistance value when the amount of distortion of the magnetoresistive element 10 is 0 is set to substantially the same value between the magnetoresistive element portion R4, the second magnetoresistive element portion R2, and the third magnetic resistance element portion R3. Can be done. In addition, the change range of resistance is made substantially equal between the first magnetoresistive element R1 and the fourth magnetoresistive element R4 and the second magnetoresistive element R2 and the third magnetoresistive element R3. Can be done.

Further, by setting the angles θ1, θ2, and θ3 in the above range in a state where no external force is applied to the deflection region 4, the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4 are set as described above. The amount of distortion of the magnetoresistive element 10 between the first half-bridge circuit Hf1 composed of the above and the second half-bridge circuit Hf2 composed of the second magnetoresistive element R2 and the third magnetoresistive element R3. The offset voltage in the case of 0 can be set to substantially the same value. In addition, the output range can be made substantially the same between the first half-bridge circuit Hf1 and the second half-bridge circuit Hf2.

Further, by setting the angles θ1, θ2, and θ3 in the above range in the state where no external force is applied to the deflection region 4, the output voltage of the full bridge circuit in the non-deformed state is set to 0, and the output of the full bridge circuit is output. The range can be increased.

As described above, in the sensor 100 according to the first embodiment, the sensitivity can be improved by a configuration including a full bridge circuit composed of a plurality of magnetoresistive elements 10.

Note that, in FIGS. 9 to 13 above, the angle θ1 is 135 degrees, the angle θ2 is 45 degrees, and the angle θ3 is 225 degrees. Therefore, the magnetization direction of the free layer and the magnetization direction of the reference layer in the non-deformed state vary in the manufacturing process, and the resistance changes when the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer deviates. And the change in the output of the full bridge circuit is shown in FIGS. 14 and 15.

FIG. 14 shows the relationship between the amount of distortion of the magnetoresistive element and the resistance of a plurality of magnetoresistive elements constituting the full bridge circuit when the magnetization direction of the reference layer is shifted in the sensor according to the first embodiment. It is a figure which shows.

In FIG. 14, in the non-deformed state, the counterclockwise angle θ1 from the reference direction to the magnetization direction of the free layer is 135 degrees. The counterclockwise angle θ2 from the reference direction in the first magnetic resistance element 11 and the fourth magnetic resistance element 14 to the magnetization direction of the reference layer 24, and the above in the second magnetic resistance element 12 and the third magnetic resistance element 13. The counterclockwise angle θ3 from the reference direction to the magnetization direction of the reference layer 24 is changed.

In the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ2 from the reference direction to the magnetization direction of the reference layer 24 is changed in the range of 45 degrees to 55 degrees. When the angle θ1 is 135 degrees and the angle θ2 is 45 degrees in the non-deformed state, the amount of deviation of the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer is 0 degree.

In the second magnetoresistive element 12 and the third magnetoresistive element 13, the counterclockwise angle θ3 from the reference direction to the magnetization direction of the reference layer 24 is changed in the range of 225 degrees to 235 degrees. When the angle θ1 in the non-deformed state is 135 degrees and the angle θ3 is 235 degrees, the amount of deviation of the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer is 0 degree.

In this case, in the first magnetoresistive element unit R1 and the fourth magnetoresistive element unit R4, as the amount of deviation of the relative angles increases, the amount of distortion of the magnetoresistive element becomes negative and positive. In both cases, the value that becomes substantially constant decreases.

On the other hand, in the second magnetoresistive element portion R2 and the third magnetoresistive element portion R3, as the amount of deviation of the relative angles increases, both the case where the amount of distortion of the magnetoresistive element is negative and the case where the strain amount is positive In, the value that becomes substantially constant increases.

When the strain amount of the magnetoresistive element is 0, almost the same resistance value is maintained regardless of the relative angle deviation amount.

FIG. 15 is a diagram showing the relationship between the amount of strain of the magnetoresistive element and the output voltage of the full bridge circuit when the magnetization direction of the reference layer is shifted in the sensor according to the first embodiment. Also in FIG. 15, the relative angle deviation amount is the same as in FIG.

In this case, as the amount of deviation of the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer increases, the output of the full bridge circuit is when the strain amount of the magnetoresistive element is negative and positive. In both cases, the value that becomes substantially constant decreases.

When the strain amount of the magnetoresistive element is 0, almost the same output value is maintained regardless of the relative angle deviation amount. Even when the relative angular deviation between the magnetization direction of the free layer and the magnetization direction of the reference layer deviates, the output range (difference between the upper limit value and the lower limit value of the output) is substantially the same.

FIG. 16 shows the output of the full bridge circuit in the sensor according to the first embodiment when the strain amount of the magnetoresistive element is + 0.02% and when the strain amount of the magnetoresistive element is −0.02%. It is a figure which shows the relationship between the difference of an absolute value and the difference of an output range, and the deviation angle of a reference layer in the magnetization direction. Also in FIG. 15, the relative angle deviation amount is the same as in FIG.

As shown in FIG. 16, the difference in the absolute value of the output of the full bridge circuit when the strain amount of the magnetoresistive element is + 0.02% and −0.02% is the amount of deviation of the relative angles. Increases as the number increases.

When the relative angle deviation is 10 degrees, the difference in the absolute value of the output of the full bridge circuit between the case where the amount of distortion of the magnetoresistive element is + 0.02% and the case where it is -0.02%. Can be set to 30% or less with respect to the case where the relative angle deviation amount is 0.

That is, by setting the angle θ1 to 135 degrees ± 5 degrees, the angle θ2 to 45 degrees ± 5 degrees, and the angle θ3 to 225 degrees ± 5 degrees, the difference between the absolute values of the outputs is 30%. It can be as follows.

When the relative angle deviation is 6 degrees, the difference in the absolute value of the output of the full bridge circuit between the case where the amount of distortion of the magnetoresistive element is + 0.02% and the case where it is -0.02%. Can be 20% or less with respect to the case where the relative angle deviation amount is 0.

That is, by setting the angle θ1 to 135 degrees ± 3 degrees, the angle θ2 to 45 degrees ± 3 degrees, and the angle θ3 to 225 degrees ± 3 degrees, the difference between the absolute values of the outputs is 20%. It can be as follows.

When the relative angle deviation is 3 degrees, the difference in the absolute value of the output of the full bridge circuit between the case where the amount of distortion of the magnetoresistive element is + 0.02% and the case where it is -0.02%. Can be set to 10% or less with respect to the case where the relative angle deviation amount is 0.

That is, by setting the angle θ1 to 135 degrees ± 1.5 degrees, the angle θ2 to 45 degrees ± 1.5 degrees, and the angle θ3 to 225 degrees ± 1.5 degrees, the absolute output is absolute. The difference between the values can be 10% or less.

On the other hand, the output range of the full bridge circuit when the strain amount of the magnetoresistive element is + 0.02% and -0.02% increases as the relative angle deviation amount increases. The amount of increase is small. That is, the output range of the full bridge circuit when the strain amount of the magnetoresistive element is + 0.02% and −0.02% is even when the relative angle deviation amount increases. It is almost constant. That is, even when the angle θ1 is 135 degrees ± 5 degrees, the angle θ2 is 45 degrees ± 5 degrees, and the angle θ3 is 225 degrees ± 5 degrees, the angle θ1 is 135 degrees. An output range substantially similar to that in the case where the angle θ2 is 45 degrees and the angle θ3 is 225 degrees is maintained.

As described above, in the sensor 100 according to the first embodiment, it is possible to increase the output range of the full bridge circuit while setting the output voltage of the full bridge circuit to 0 in the non-deformed state, and a plurality of magnetoresistive elements. The sensitivity can be improved by the configuration including the full bridge circuit configured by 10.

(Production method)
17 to 24 are diagrams showing the first to eighth steps of the sensor manufacturing process according to the first embodiment. A method of manufacturing the sensor 100 according to the first embodiment will be described with reference to FIGS. 17 to 24.

When manufacturing the sensor 100 according to the first embodiment, as shown in FIG. 17, in the first step, a substrate 61 on which the film portion 62 to be the diaphragm portion is formed is prepared. The film portion 62 is an insulating layer such as silicon oxide or silicon nitride. The film portion 62 may be a semiconductor material such as silicon or a metal material.

Subsequently, dry etching is performed on the surface of the film portion 62 to form a trench portion (not shown), and a wiring portion composed of Cu or the like is formed in the trench portion by a plating method or a sputtering method. Next, the surplus conductive portion that rises outward from the opening of the trench portion is polished by a chemical mechanical polishing method (CMP).

Next, as shown in FIG. 18, in the second step, the lower electrode film 63, the TMR laminated film 64, and the upper electrode film 65 are laminated on the film portion 62. Specifically, the lower electrode film 63, the pinning film, the pin film, the magnetic coupling film, the reference film, the tunnel barrier film, the free film, the separation film, the bias film, and the upper electrode film 65 are laminated.

After patterning, the lower electrode film 63, pinning film, pin film, magnetic coupling film, reference film, tunnel barrier film, free film, separation film, bias film, and upper electrode film are formed into the lower electrode layer 20, the pinning layer 21, and the pins. It becomes a layer 22, a magnetic coupling layer 23, a reference layer 24, a tunnel barrier layer 25, a free layer 26, a separation layer 27, a bias layer 28, and an upper electrode layer 29.

When the film portion 62 is a semiconductor material or a metal material, an insulating layer is formed on the film portion 62 that is a region where the magnetoresistive element is formed, and then the lower electrode film 63 and the TMR laminated film are formed. 64, the upper electrode film 65 may be laminated.

As the lower electrode film 63, for example, Ru / Ta is formed. As the pin film / pinning film (ferromagnetic film / antiferromagnetic film) on the upper layer of the lower electrode film 63, for example, CoFe / IrMn is formed. This laminated film functions as a pin layer due to exchange bonding caused by annealing in a magnetic field, which will be described later. PtMn may be formed as a pinning film.

As the magnetic coupling film (non-magnetic film) on the upper layer of the pin film (ferromagnetic film), for example, Ru is formed, and as the reference film (lower ferromagnetic film) on the upper layer of the non-magnetic film, for example, CoFeB is formed. To do. The reference film / magnetic bond film / pin film (lower ferromagnetic film / non-magnetic film / ferromagnetic film) constitutes a synthetic anti-ferromagnetic (SAF) bonding structure.

As the tunnel barrier film, for example, MgO is formed, and as the free film (upper ferromagnetic film) on the tunnel barrier film, for example, FeB / CoFeB is formed. FeB has a large magnetostrictive constant, is amorphous, and has a small magnetocrystalline anisotropy.

Cu is formed as a separation film. The separation membrane is not limited to Cu as described above, and can be appropriately selected depending on the positive magnetic coupling and the negative magnetic coupling.

As the bias film (antiferromagnetic film / ferromagnetic film), IrMn / CoFeB is formed. The blocking temperature of the antiferromagnetic film formation in the bias film is lower than the blocking temperature of the antiferromagnetic film on the reference film side. As a result, as will be described later, the magnetization direction of the reference layer and the bias magnetic field direction of the bias layer can be made different.

When the antiferromagnetic film on the bias film and the antiferromagnetic film on the reference film are formed of the same material, the antiferromagnetic film on the reference film is made thicker than the antiferromagnetic film on the bias film. As the upper electrode film 65, for example, Ta / Ru is formed.

Subsequently, the substrate 61 on which the lower electrode film 63, the TMR laminated film 64, and the upper electrode film 65 are formed is annealed in a magnetic field.

Next, as shown in FIG. 19, in the third step, the TMR laminated film 64 and the upper electrode film 65 are patterned into desired shapes by using photolithography and dry etching.

Subsequently, as shown in FIG. 20, in the fourth step, a part of the lower electrode film 63 is removed by using photolithography and dry etching to form a wiring pattern. As a result, a plurality of magnetoresistive elements 10 are formed. A part of the plurality of magnetoresistive elements is electrically connected by a wiring pattern composed of the lower electrode film 63.

Next, as shown in FIG. 21, in the fifth step, the substrate 61 is covered with the insulating film 66 so as to cover the plurality of magnetoresistive elements 10. As the insulating film 66, for example, SiO ₂ can be adopted.

Subsequently, as shown in FIG. 22, in the sixth step, a part of the insulating film 66 is removed by photolithography and dry etching to form a contact hole. Next, metal wirings 31, 32, and 33 are formed in the contact hole by photolithography and lift-off. Cu can be used as the

metal wirings

31, 32, 33.

Subsequently, as shown in FIG. 23, in the seventh step, a passivation film 67 is formed on the insulating film 66 so as to cover the

metal wirings

31, 32, and 33. As the passivation film 67, for example, SiO ₂ can be adopted.

Next, a part of the passivation film 67 is removed to form an opening by using photolithography and dry etching. Subsequently, electrode portions P1, P2, P3, and P4 are formed in the opening by photolithography and lift-off.

Next, fix the magnetization direction of the reference layer. Here, as shown in FIG. 4 described above, the magnetization direction is determined according to the shape of the deflection region 4 formed in the subsequent step and the configuration of the full bridge circuit.

As a method of fixing the magnetization direction of the reference layer in a different direction for each magnetic resistance element 10 of the full bridge circuit, a method of locally heating by laser irradiation while applying a magnetic field with an electromagnet or a permanent magnet, or a method of applying a magnetic field with an electromagnet or a permanent magnet. There are a method of energizing and heating the heater wiring arranged in the vicinity of the element while applying the force, or a method of heat-treating with a jig that can locally apply a magnetic field.

Next, determine the direction of the bias magnetic field. Specifically, a method substantially similar to the method for fixing the magnetization direction of the reference layer described above is performed. At this time, the temperature at which each magnetoresistive element 10 is heated is set to a temperature at which the magnetization direction of the reference layer does not change.

Next, as shown in FIG. 24, in the eighth step, a part of the substrate 61 is used from the main surface side of the substrate 61 located on the side opposite to the side where the magnetoresistive element 10 is formed by using dry etching. Is removed to form the cavity 5. Here, the cavity 5 refers to a space surrounded by the inner wall of the substrate 61. By forming the cavity portion 5 in this way, the deflection region 4 of the diaphragm portion 3 is formed. Dry etching has been exemplified as a method for forming the cavity, but other processing methods such as wet etching may be used.

Through such a manufacturing process, as described above, the sensor 100 according to the first embodiment, which includes a full bridge circuit composed of a plurality of magnetoresistive elements and can improve the sensitivity, is manufactured.

(Form of comparison)
FIG. 25 is a diagram showing the magnetization direction of the free layer and the magnetization direction of the reference layer in the non-deformed state in which the diaphragm portion is not deformed in the sensor according to the comparative form.

As shown in FIG. 25, the sensor 100X according to the comparative embodiment has a magnetization direction of the reference layer in the first magnetoresistive element 11 and the third magnetoresistive element 13 when compared with the sensor 100 according to the first embodiment. In addition to being different, the magnetization directions of the reference layers in the second magnetoresistive element 12 and the fourth magnetoresistive element 14 are different. That is, in the first magnetic resistance element 11 and the fourth magnetic resistance element 14, the counterclockwise angle θ2 from the reference direction to the magnetization direction of the reference layer 24 is different from that of the first embodiment, and the second magnetic resistance In the element 12 and the third magnetic resistance element 13, the counterclockwise angle θ3 from the reference direction to the magnetization direction of the reference layer 24 is different from that of the embodiment.

In the sensor 100X according to the comparative form, the angle θ2 is 0 degrees, and the angle θ3 is 180 degrees.

FIG. 26 is a diagram showing the direction of stress-induced anisotropy generated in the first state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the comparative form. FIG. 26 shows a case where the magnetostrictive constant of the free layer is positive.

As shown in FIG. 26, even in the comparative form, in the first deformed state of the diaphragm portion 3, the tensile stress acts along the radial direction of the deflection region 4 as shown by the black arrow. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to extend in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy develops toward the radial outer side of the deflection region 4. The direction of stress-induced anisotropy is parallel to the virtual straight line VL1 connecting the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 as shown by the black arrow shown in the magnetoresistive element 10 of FIG.

Specifically, in the first state, in the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ4 from the reference direction to the direction of stress-induced anisotropy is approximately 90 degrees. It becomes.

FIG. 27 is a diagram showing the direction of stress-induced anisotropy generated in the second state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the comparative form.

As shown in FIG. 27, even in the comparative form, in the second deformed state of the diaphragm portion 3, the compressive stress acts along the radial direction of the deflection region 4 by the black arrow. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to contract in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy appears toward the tangential direction of the outer edge of the deflection region 4. The direction of stress-induced anisotropy is orthogonal to the virtual straight line VL1 connecting the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 as shown by the black arrow shown in the magnetoresistive element 10 of FIG. That is, the direction of stress-induced anisotropy is parallel to the reference line BL1.

Specifically, in the first state, in the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ4 from the reference direction to the direction of stress-induced anisotropy is approximately 180 degrees. It becomes.

In the first state, the counterclockwise angle θ5 from the reference direction to the stress-induced anisotropy direction is approximately 180 degrees also in the second magnetoresistive element 12 and the third magnetoresistive element 13.

FIG. 28 is a diagram showing the relationship between the amount of distortion of the magnetoresistive element due to the deformation of the diaphragm portion and the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer in the sensor according to the comparative form. ..

As shown in FIG. 28, in the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4 (first magnetic resistance element 11 and fourth magnetic resistance element 14), the magnetic resistance element 10 is compressed from the non-deformed state. As a result, the relative angle between the magnetizing direction of the free layer and the magnetizing direction of the reference layer changes from 135 degrees to approach 180 degrees. Further, in the first magnetoresistive element R1 and the fourth magnetoresistive sensor R4, as the magnetoresistive element 10 is pulled from the non-deformed state, the magnetization direction of the free layer and the magnetization direction of the reference layer are relative to each other. The angle changes from 135 degrees to approaching approximately 90 degrees.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (the second magnetoresistive element 12 and the third magnetoresistive element 13), as the magnetic resistance element 10 is compressed from the non-deformed state, the free layer becomes The relative angle between the magnetizing direction and the magnetizing direction of the reference layer changes from about 45 degrees to approach 0 degrees. Further, in the second magnetoresistive element R2 and the third magnetoresistive sensor R3, as the magnetoresistive element 10 is pulled from the non-deformed state, the magnetization direction of the free layer and the magnetization direction of the reference layer are relative to each other. The angle changes from about 45 degrees to approaching about 90 degrees.

As described above, in the comparative form, the range of the relative angles between the magnetization direction of the free layer and the magnetization direction of the reference layer in the first magnetic resistance element portion R1 and the fourth magnetic resistance element portion R4, and the second magnetic resistance The range of relative angles between the magnetization direction of the free layer and the magnetization direction of the reference layer in the element unit R2 and the third magnetic resistance element unit R3 is different from each other.

FIG. 29 is a diagram showing the relationship between the relative angle shown in FIG. 28 and the resistance of a plurality of magnetoresistive element portions constituting the full bridge circuit in the sensor according to the comparative form.

As shown in FIG. 29, as the relative angle between the magnetization direction of the free layer and the magnetization direction of the reference layer increases, the first magnetoresistive element R1, the second magnetoresistive element R2, and the third magnetoresistive element The resistance increases in each of the portion R3 and the fourth magnetoresistive element portion R4. However, as described above, the relative angles are different between the first magnetoresistive element R1 and the fourth magnetoresistive element R4 and the second magnetoresistive element R2 and the third magnetoresistive element R3. In addition, the range of resistance in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 is different from the range of resistance in the second magnetoresistive element R2 and the third magnetoresistive element R3.

FIG. 30 is a diagram showing the relationship between the amount of strain of the magnetoresistive element due to the deformation of the diaphragm portion and the resistance of a plurality of magnetoresistive element portions constituting the full bridge circuit in the sensor according to the comparative form.

As shown in FIG. 30, in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 (first magnetoresistive element 11 and fourth magnetoresistive element 14), the magnetoresistive element 10 is compressed from the non-deformed state. As it is done, the resistance changes from about 0.07 kΩ to approach about 0.10 kΩ. Further, in the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4, as the magnetoresistive element 10 is pulled from the non-deformed state, the resistance decreases from about 0.07 kΩ to about 0.05 kΩ. It changes to get closer.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (second magnetoresistive element 12 and third magnetoresistive element 13), as the magnetoresistive element 10 is compressed from the non-deformed state, the resistance is increased. It decreases from about 0.04 kΩ and changes to approach about 0.035 kΩ. Further, in the second magnetoresistive element portion R2 and the third magnetoresistive element portion R3, as the magnetoresistive element 10 is pulled from the non-deformed state, the resistance increases from approximately 0.04 kΩ to approximately 0.05 kΩ. It changes to get closer.

FIG. 31 is a diagram showing the relationship between the amount of distortion of the magnetoresistive element due to the deformation of the diaphragm portion and the output voltage of the half-bridge circuit in the sensor according to the comparative form.

As shown in FIG. 31, in the first magnetoresistive element R1 and the fourth magnetoresistive element R4 (the first magnetoresistive element 11 and the fourth magnetoresistive element 14), the magnetoresistive element 10 is compressed from the non-deformed state. As a result, the output of the first half-bridge circuit Hf1 increases from about 1.9V and changes to approach about 2.2V. Further, in the first magnetoresistive element portion R1 and the fourth magnetoresistive element portion R4, the output of the first half-bridge circuit Hf1 decreases from approximately 1.9 V as the magnetoresistive element 10 is pulled from the non-deformed state. Then, it changes so as to approach about 1.5V.

In the second magnetoresistive element R2 and the third magnetoresistive element R3 (the second magnetoresistive element 12 and the third magnetoresistive element 13), the second half as the magnetoresistive element 10 is compressed from the non-deformed state. The output of the bridge circuit Hf2 decreases from about 1.1V and changes to approach about 0.8V. Further, in the second magnetoresistive element portion R2 and the third magnetoresistive element portion R3, the output of the second half bridge circuit Hf2 increases from approximately 1.1 V as the magnetoresistive element 10 is pulled from the non-deformed state. Then, it changes so as to approach about 1.5V.

FIG. 32 is a diagram showing the relationship between the amount of distortion of the magnetoresistive element due to the deformation of the diaphragm portion and the output voltage of the full bridge circuit in the sensor according to the comparative form.

As shown in FIG. 32, the output voltage of the full bridge circuit increases from 900 mV as the magnetoresistive element 10 is compressed from the non-deformed state, and changes so as to approach approximately 1500 mV. Further, the output voltage of the full bridge circuit decreases from 900 mV as the magnetoresistive element 10 is pulled from the non-deformed state, and changes so as to approach approximately 100 mV.

As described above, in the sensor 100X according to the comparative embodiment, the angles θ2 and the angles θ3 are different from those in the first embodiment, so that the first magnetoresistive element unit R1 and the fourth magnetism are different as described above. The resistance value when the strain amount of the magnetic resistance element 10 is 0 is different between the resistance element portion R4, the second magnetic resistance element portion R2, and the third magnetic resistance element portion R3. In addition, the change range of resistance is also different between the first magnetoresistive element R1 and the fourth magnetoresistive element R4 and the second magnetoresistive element R2 and the third magnetoresistive element R3.

Further, a second half-bridge circuit Hf1 composed of a first magnetoresistive element R1 and a fourth magnetoresistive element R4, and a second magnetoresistive element R2 and a third magnetoresistive sensor R3. The offset voltage when the amount of distortion of the magnetoresistive element 10 is 0 is different from that of the half-bridge circuit Hf2. In addition, the output range is also different between the first half-bridge circuit Hf1 and the second half-bridge circuit Hf2.

As a result, in the sensor 100X according to the comparative form, the output range in the full bridge circuit becomes smaller than that in the first embodiment, and the sensitivity is lowered.

(Embodiment 2)
FIG. 33 is a diagram showing the magnetization direction of the free layer and the magnetization direction of the reference layer in the non-deformed state in which the diaphragm portion is not deformed in the sensor according to the second embodiment. The sensor 100A according to the second embodiment will be described with reference to FIG. 33.

As shown in FIG. 33, the sensor 100A according to the second embodiment is provided with the shape of the deflection region 4 and the slit 4a in the deflection region 4 when compared with the sensor 100 according to the first embodiment. It differs in that. Other configurations are almost the same.

The deflection region 4 has a rectangular shape when viewed in a plan view (when viewed from the normal direction of the deflection region 4). Specifically, the deflection region 4 has a square shape. The deflection region 4 has a plurality of side portions (first side portion 41, second side portion 42, third side portion 43, and fourth side portion 44) and a plurality of corner portions. The deflection region 4 is provided with a slit 4a that divides the deflection region 4 into a plurality of parts in the circumferential direction. The slit 4a is provided so as to connect a plurality of corners diagonally. The plurality of regions divided by the slit 4a are provided so as to be rotationally symmetric with respect to the central portion of the deflection region 4. The plurality of regions has a triangular outer shape, but is not limited to such a shape.

The first side portion 41 and the fourth side portion 44 are arranged so as to face each other, and the second side portion 42 and the third side portion 43 are the first side portion 41 and the fourth side portion 44. Both ends are connected and arranged so as to face each other.

The plurality of magnetoresistive elements 10 are arranged in the deflection region 4 so that the center of gravity of each is along the outer edge of the deflection region 4. Specifically, the plurality of first magnetoresistive elements 11 are arranged along the first side portion 41. The plurality of second magnetoresistive elements 12 are arranged along the second side portion 42. The plurality of third magnetoresistive elements 13 are arranged along the third side portion 43. The plurality of fourth magnetoresistive elements 14 are arranged along the fourth side portion 44.

The plurality of first magnetoresistive elements 11 are arranged in the central portion of the first side portion 41. The plurality of second magnetoresistive elements 12 are arranged at the center of the second side portion 42. The plurality of third magnetoresistive elements 13 are arranged at the center of the third side portion 43. The plurality of fourth magnetoresistive elements 14 are arranged at the center of the fourth side portion 44. By arranging in this way, the directions of the tensile stress or the compressive stress acting on the plurality of magnetoresistive elements arranged on each side can be made substantially the same direction.

In each of the first magnetic resistance element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element 14, the first magnetic resistance element 11, the second magnetic resistance element 12, and the third magnetic resistance The straight line that is orthogonal to the virtual straight line VL1 that connects each center of gravity of the element 13 and the fourth magnetoresistive element 14 to the outer edge of the deflection region 4 at the shortest distance and passes through the center of gravity is defined as the reference line BL1.

FIG. 34 is a diagram showing the direction of stress-induced anisotropy generated in the first deformed state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the second embodiment. In FIG. 34, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 34 shows a case where the magnetostrictive constant of the free layer is positive.

As shown in FIG. 34, in the first deformation state, tensile stress acts on the plurality of magnetoresistive elements 10. Specifically, the tensile stress acts along the direction perpendicular to each side (the direction parallel to the above-mentioned virtual straight line VL1) as shown by the black arrow in FIG. 34. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to extend in a direction parallel to the virtual straight line VL1.

At this time, stress-induced anisotropy is exhibited in each of the plurality of magnetoresistive elements 10. The direction of stress-induced anisotropy is parallel to the virtual straight line VL1 that connects the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 at the shortest distance, as shown by the black arrow shown in the magnetoresistive element 10 of FIG. ..

In this case, in the first magnetoresistive element 11 and the fourth magnetoresistive element 14, the counterclockwise angle θ4 from the reference direction to the direction of stress-induced anisotropy is approximately 90 degrees.

Also in the second magnetoresistive element 12 and the third magnetoresistive element 13, the counterclockwise angle θ5 from the reference direction to the direction of stress-induced anisotropy is approximately 90 degrees.

FIG. 35 is a diagram showing the direction of stress-induced anisotropy generated in the second deformed state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the second embodiment. In FIG. 35, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 35 shows a case where the magnetostrictive constant of the free layer is positive.

As shown in FIG. 35, in the second deformation state, compressive stress acts on the plurality of magnetoresistive elements 10. Specifically, the compressive stress acts along the direction perpendicular to each side (direction parallel to the above-mentioned virtual straight line VL1) as shown by the black arrow in FIG. 35. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to contract in a direction parallel to the virtual straight line VL1.

At this time, stress-induced anisotropy is exhibited in each of the plurality of magnetoresistive elements 10. The direction of stress-induced anisotropy is orthogonal to the virtual straight line VL1 connecting the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 as shown by the black arrow shown in the magnetoresistive element 10 of FIG. That is, the direction of stress-induced anisotropy is parallel to the reference line BL1.

As described above, also in the second embodiment, the relationship between the angles θ1, the angle θ2, the angle θ3, the angle θ4, and the angle θ5 in the non-deformed state, the first deformed state, and the second deformed state is the embodiment. It becomes the same as 1. As a result, even in the sensor 100A according to the second embodiment, substantially the same effect as that of the first embodiment can be obtained.

The sensor 100A according to the second embodiment is manufactured in accordance with the manufacturing method of the sensor 100 according to the first embodiment. In this case, in the step according to the third step of the first embodiment, the TMR laminated film 64 and the upper electrode film 65 are arranged so that the plurality of magnetoresistive elements 10 are arranged in the center of each side portion as described above. Patterning. In the step according to the eighth step of the first embodiment, the cavity portion 5 is formed so that the deflection region 4 has a rectangular shape. Further, a slit 4a is formed in the deflection region 4.

In the second embodiment, the case where the slit 4a is provided in the deflection region 4 has been described as an example, but the present invention is not limited to this, and the slit 4a may not be provided. When the slit 4a is provided, the stress input to the diaphragm portion 3 in the manufacturing process can be released by the slit 4a.

(Embodiment 3)
FIG. 36 is a diagram showing the magnetization direction of the free layer and the magnetization direction of the reference layer in the non-deformed state in which the diaphragm portion is not deformed in the sensor according to the third embodiment. The sensor 100B according to the third embodiment will be described with reference to FIG. 36.

As shown in FIG. 36, the sensor 100B according to the third embodiment is different from the sensor 100 according to the first embodiment in that a plurality of magnetoresistive elements 10 have a magnetic vortex structure. Other configurations are almost the same.

Each of the plurality of magnetoresistive elements 10 has a disk shape. As a result, the free layer included in each of the plurality of magnetoresistive elements 10 also has a disk shape. When the strain amount of the magnetic resistance element 10 is zero, the free layer having a magnetic vortex structure has a point-symmetrical magnetization direction in the plane and has magnetization in the plane perpendicular direction at the center thereof. That is, it can be considered to be equivalent to the case of biasing in the direction perpendicular to the plane.

In this case, as will be described later, the magnetization fixing direction of the reference layer is set so that the relative angle with respect to the direction of the stress-induced anisotropy that appears when the magnetoresistive element is pulled or compressed is 45 degrees. ..

In general, when the magnetoresistive element 10 has a disk shape and stress is applied to the magnetoresistive element 10 to form an elliptical shape, the direction of stress-induced anisotropy is determined only by the inverse magnetostrictive effect. , It becomes difficult to uniquely determine whether the elliptical shape faces one side or the other side in the long axis direction.

Further, in the laminated structure of the free layer / tunnel barrier layer / reference layer, in the case of a general tonnel barrier layer film thickness, the free layer has a weak interlayer exchange bond that tries to align in the direction parallel to the magnetization direction of the reference layer. Power works. When the direction of stress-induced anisotropy is governed by the interlayer exchange coupling force, the output characteristic with respect to the positive and negative distortion of the magnetoresistive element becomes an even function.

Therefore, also in the third embodiment, the free layer is biased in the direction of 90 degrees with respect to the magnetization direction of the reference layer in order to obtain the output characteristics of the odd function. Further, in order to uniquely determine the magnetization direction of the free layer when strain is applied to the magnetoresistive element, the strength of the bias magnetic field applied to the free layer is determined by the exchange coupling magnetic field acting between the free layer and the reference layer. It is larger than the strength.

Also in the third embodiment, similarly to the first embodiment, the first magnetic resistance in each of the first magnetic resistance element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element 14. It is orthogonal to the virtual straight line VL1 that connects the center of gravity of each of the element 11, the second magnetic resistance element 12, the third magnetic resistance element 13, and the fourth magnetic resistance element 14 to the outer edge of the deflection region 4 at the shortest, and passes through the center of gravity. Let the straight line be the reference line BL1.

In each of the first magnetoresistive element 11, the second magnetoresistive element 12, the third magnetoresistive element 13, and the fourth magnetoresistive element 14, the intersection of the virtual straight line VL1 and the outer edge of the deflection region 4 is set at the reference line BL1. The direction from the center of gravity to the right when viewed from the front is defined as the reference direction.

Even in this case, the first magnetoresistive element 11, the second magnetoresistive element 12, and the third magnetoresistive element are in the state where the diaphragm portion 3 is not deformed, that is, when no external force is applied to the deflection region 4. In each of the 13 and the 4th magnetoresistive element 14, the counterclockwise angle θ1 from the reference direction to the magnetization direction of the free layer (the direction in which the magnetization of the free layer is directed by the bias magnetic field) is 135 degrees ± 5 degrees. is there.

FIG. 37 is a diagram showing the direction of stress-induced anisotropy generated in the first deformed state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the third embodiment. In FIG. 37, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 37 shows a case where the magnetostrictive constant of the free layer is positive.

As shown in FIG. 37, in the first deformation state, tensile stress acts on the plurality of magnetoresistive elements 10. Specifically, the tensile stress acts along the radial direction of the deflection region 4, as shown by the black arrow in FIG. 37. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to extend in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy develops toward the radial outer side of the deflection region 4. The direction of the stress-induced anisotropy is parallel to the virtual straight line VL1 connecting the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 as shown by the black arrow shown in the magnetoresistive element 10 of FIG. 37.

FIG. 38 is a diagram showing the direction of stress-induced anisotropy generated in the second deformed state in which the diaphragm portion is deformed and the direction of magnetization of the reference layer in the sensor according to the second embodiment. In FIG. 38, the outer edge of the magnetoresistive element 10 and the magnetization direction of the free layer in the non-deformed state are shown by broken lines. FIG. 38 shows a case where the magnetostrictive constant of the free layer is positive.

As shown in FIG. 38, in the second deformation state, compressive stress acts on the plurality of magnetoresistive elements 10. Specifically, the compressive stress acts along the radial direction of the deflection region 4, as shown by the black arrow in FIG. 38. As a result, each of the plurality of magnetoresistive elements 10 is deformed so as to contract in the radial direction of the deflection region 4.

At this time, stress-induced anisotropy is exhibited in each of the plurality of magnetoresistive elements 10. The direction of stress-induced anisotropy is orthogonal to the virtual straight line VL1 connecting the center of gravity of the magnetoresistive element 10 and the outer edge of the deflection region 4 as shown by the black arrow shown in the magnetoresistive element 10 of FIG. 38. That is, the direction of stress-induced anisotropy is parallel to the reference line BL1.

As described above, also in the third embodiment, the relationship between the angles θ1, the angle θ2, the angle θ3, the angle θ4, and the angle θ5 in the non-deformed state, the first deformed state, and the second deformed state is the embodiment. It becomes the same as 1. As a result, even in the sensor 100B according to the third embodiment, substantially the same effect as that of the first embodiment can be obtained.

The sensor 100B according to the third embodiment is manufactured in accordance with the manufacturing method of the sensor 100 according to the first embodiment. In this case, in the step according to the third step of the first embodiment, the TMR laminated film 64 and the upper electrode film 65 are patterned into a disk shape.

(Embodiment 4)
FIG. 39 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the fourth embodiment. The sensor 100C according to the fourth embodiment will be described with reference to FIG. 39.

As shown in FIG. 40, the sensor 100C according to the fourth embodiment has a plurality of magnetoresistive elements 10 constituting the first half-bridge circuit Hf1 and a second magnetoresistive element 10 when compared with the sensor 100B according to the third embodiment. The difference is that the disk diameters are different between the plurality of magnetoresistive elements 10 constituting the half-bridge circuit Hf2. Other configurations are almost the same.

As described above, in the fourth embodiment, the disk diameter of the free layer in the first magnetoresistive element 11 and the second magnetoresistive element 12 and the free layer in the third magnetoresistive element 13 and the fourth magnetoresistive element 14 The disk diameter is different.

Specifically, the disk diameter of the free layer in the first magnetoresistive element 11 and the second magnetoresistive element 12 becomes smaller than the disk diameter of the free layer in the third magnetoresistive element 13 and the fourth magnetoresistive element 14. There is.

As a result, the sensitivity can be reduced and the dynamic range can be increased on the first half-bridge circuit Hf1 side. On the other hand, on the second half bridge circuit Hf2 side, the sensitivity can be increased and the dynamic range can be decreased.

In this case, when either the output from the first half-bridge circuit Hf1 or the output from the second half-bridge circuit is saturated, the output from the first half-bridge circuit and the second half-bridge circuit The other of the outputs from Hf2 is used.

By properly using the dynamic range in this way, it is possible to properly detect the external force acting on the deflection region 4. Further, when the external force input to the deflection region 4 is sound, the input sound pressure level and the input dynamic range can be expanded.

Even in the case of the above-described configuration, in the sensor 100C according to the fourth embodiment, in the non-deformed state, the first deformed state, and the second deformed state, the angles θ1, the angle θ2, the angle θ3, and the angle The relationship between θ4 and the angle θ5 is the same as in the third embodiment. Therefore, the sensor 100C according to the fourth embodiment has almost the same effect as the sensor 100B according to the third embodiment.

Further, since the above-mentioned sensitivity can be adjusted by changing the disk diameter of the magnetoresistive element, the magnetoresistive element having a different sensitivity as compared with the first embodiment in which it is difficult to change the film thickness in the plane. Can be easily integrated in the same chip.

The sensor 100C according to the fourth embodiment is manufactured in accordance with the manufacturing method of the sensor 100 according to the first embodiment. In this case, in the step according to the third step of the first embodiment, the TMR laminated film 64 and the upper electrode film 65 are patterned into a disk shape. At this time, the plurality of magnetoresistive elements 10 constituting the first half-bridge circuit Hf1 and the plurality of magnetoresistive elements 10 constituting the second half-bridge circuit Hf2 are patterned so that the disk diameters are different.

(Embodiment 5)
FIG. 40 shows a non-deformed state in which the diaphragm portion (here, since the diaphragm portion is not fixed all around, it can also be expressed as a cantilever portion or a cantilever portion) in the sensor according to the fifth embodiment. It is a schematic plan view which shows. The sensor 100D according to the fifth embodiment will be described with reference to FIG. 40.

As shown in FIG. 40, the sensor 100D according to the fifth embodiment has a different configuration of the deflection region 4 when compared with the sensor 100B according to the third embodiment. Other configurations are almost the same.

In the fifth embodiment, the deflection region 4 has a first region 4A and a second region 4B separated from each other. The areas of the first region 4A and the second region 4B are different from each other.

The first region 4A and the second region 4B have a semicircular shape including an arc portion and a straight portion when viewed in a plan view. The first region 4A and the second region 4B are arranged so that the straight portions face each other. The first region 4A and the second region 4B are similar to each other. The radius of the first region 4A is larger than the radius of the second region 4B.

In the first region 4A, the first magnetoresistive element 11 and the second magnetoresistive element 12 constituting the first half-bridge circuit Hf1 are arranged. The first magnetoresistive element 11 and the second magnetoresistive element 12 are arranged so that the center of gravity of each magnetoresistive element is along the arc portion of the first region 4A of the outer edge of the deflection region 4.

In the second region 4B, the third magnetoresistive element 13 and the fourth magnetoresistive element 14 constituting the second half-bridge circuit Hf2 are arranged. The third magnetoresistive element 13 and the fourth magnetoresistive element 14 are arranged so that the center of gravity of each magnetoresistive element is along the arc portion of the second region 4B of the outer edge of the deflection region 4.

FIG. 41 is a diagram showing the relationship between frequency and sensitivity in each of the first region and the second region constituting the deflection region in the sensor according to the fifth embodiment.

As shown in FIG. 41, the resonance frequency f1 in the first region 4A and the resonance frequency f2 in the second region 4B are different from each other. The area of the first region 4A is larger than the area of the second region 4B, and the resonance frequency f1 in the first region 4A is smaller than the resonance frequency f2 in the second region 4B. In both the first region 4A and the second region 4B, the sensitivity increases in the vicinity of the resonance frequency. Since it is preferable that there is no frequency dependence of the output, a frequency domain having a constant sensitivity is used.

In the fifth embodiment, the deflection region 4 is divided into the first region 4A and the second region 4B having different resonance frequencies, and the output from the first half-bridge circuit Hf1 and the second half-bridge circuit Hf2 are divided according to the frequency. Switch the output from.

Here, when the deflection region 4 is formed by a single region having the same resonance frequency as the first region 4A, the range in which the sensitivity is constant is R11.

In the fifth embodiment, as described above, by dividing the deflection region 4 into the first region 4A and the second region 4B having different resonance frequencies, a range having a constant sensitivity is included from R11 to R11 and R12. It can be extended to the range. As a result, the frequency band that can be detected by the sensor 100D can be expanded.

Even in the case of the above-described configuration, in the sensor 100D according to the fifth embodiment, in the non-deformed state, the first deformed state, and the second deformed state, the angles θ1, the angle θ2, the angle θ3, and the angle The relationship between θ4 and the angle θ5 is the same as in the third embodiment. Therefore, the sensor 100D according to the fifth embodiment has almost the same effect as the sensor 100B according to the third embodiment.

(Embodiment 6)
FIG. 42 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the sixth embodiment. The sensor 100E according to the sixth embodiment will be described with reference to FIG. 42.

As shown in FIG. 42, the sensor 100E according to the sixth embodiment is different in that the plurality of magnetoresistive elements 10 have a magnetic vortex structure when compared with the sensor 100A according to the second embodiment. That is, each of the plurality of magnetoresistive elements 10 has a disk shape.

Even in the case of being configured in this way, in the sensor 100E according to the sixth embodiment, in the non-deformed state, the first deformed state, and the second deformed state, the angles θ1, the angle θ2, the angle θ3, and the angle θ4 , And the angle θ5 are the same as in the second embodiment. Therefore, the sensor 100E according to the sixth embodiment has almost the same effect as the sensor 100A according to the second embodiment.

(Embodiment 7)
FIG. 43 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the seventh embodiment. The sensor 100F according to the seventh embodiment will be described with reference to FIG. 43.

As shown in FIG. 43, the sensor 100F according to the seventh embodiment has a plurality of magnetoresistive elements 10 constituting the first half-bridge circuit Hf1 and a second magnetoresistive element 10 when compared with the sensor 100E according to the sixth embodiment. The difference is that the disk diameters are different between the plurality of magnetoresistive elements 10 constituting the half-bridge circuit Hf2. Other configurations are almost the same.

In this case, when either the output from the first half-bridge circuit Hf1 or the output from the second half-bridge circuit Hf2 is saturated, the output from the first half-bridge circuit Hf1 and the second half bridge The other of the outputs from circuit Hf2 is used.

Even in the case of the above-described configuration, in the sensor 100F according to the seventh embodiment, the angles θ1, the angle θ2, the angle θ3, and the angles in the non-deformed state, the first deformed state, and the second deformed state. The relationship between θ4 and the angle θ5 is the same as in the sixth embodiment. Therefore, the sensor 100F according to the seventh embodiment has almost the same effect as the sensor 100E according to the sixth embodiment.

(Embodiment 8)
FIG. 44 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the eighth embodiment. The sensor 100G according to the eighth embodiment will be described with reference to FIG. 44.

As shown in FIG. 44, the sensor 100G according to the eighth embodiment has a different configuration of the deflection region 4 when compared with the sensor 100E according to the sixth embodiment. Other configurations are almost the same.

In the eighth embodiment, the deflection region 4 has a first region 4A and a second region 4B separated from each other. The areas of the first region 4A and the second region 4B are different from each other.

The first region 4A and the second region 4B have a substantially isosceles triangular shape when viewed in a plan view. The first region 4A and the second region 4B are arranged so that their hypotenuses face each other. The first region 4A and the second region 4B are similar to each other. The area of the first region 4A is larger than the area of the second region 4B.

Due to the difference in area in this way, the resonance frequency f1 in the first region 4A and the resonance frequency f2 in the second region 4B are different from each other as in the fifth embodiment. The area of the first region 4A is larger than the area of the second region 4B, and the resonance frequency f1 in the first region 4A is smaller than the resonance frequency f2 in the second region 4B.

In the eighth embodiment, the deflection region 4 is divided into the first region 4A and the second region 4B having different resonance frequencies, and the output from the first half-bridge circuit Hf1 and the second half-bridge circuit Hf2 are divided according to the frequency. Switch the output from.

As a result, the sensitivity can be expanded in a certain range, and the frequency band that can be detected by the sensor 100G can be expanded.

Even in the case of the above-described configuration, in the sensor 100G according to the eighth embodiment, the angles θ1, the angle θ2, the angle θ3, and the angles are in the non-deformed state, the first deformed state, and the second deformed state. The relationship between θ4 and the angle θ5 is the same as in the sixth embodiment. Therefore, the sensor 100G according to the eighth embodiment has almost the same effect as the sensor 100E according to the sixth embodiment.

(Embodiment 9)
FIG. 45 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the ninth embodiment. FIG. 46 is a schematic perspective view showing the configuration of the magnetoresistive element and its surroundings in the sensor according to the ninth embodiment. FIG. 47 is a schematic cross-sectional view of the magnetoresistive element and its peripheral configuration according to the ninth embodiment. The sensor 100H according to the ninth embodiment will be described with reference to FIGS. 45 to 47.

As shown in FIGS. 45 to 47, the sensor 100H according to the ninth embodiment has the first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52 when compared with the sensor E according to the sixth embodiment. And the current control unit 55 (see FIG. 46) is further provided. Other configurations are almost the same.

The first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52 include a first magnetoresistive element unit R1, a second magnetoresistive element unit R2, a third magnetoresistive element unit R3, and a fourth magnetoresistive element unit R4. It is provided in each of.

The second cancel magnetic field generation unit 52, the first cancel magnetic field generation unit 51, and the magnetoresistive element 10 are laminated in this order. A second insulating layer 54 is provided between the second cancel magnetic field generation unit 52 and the first cancel magnetic field generation unit 51. A first insulating layer 53 is provided between the first canceling magnetic field generation unit 51 and the lower electrode layer 20.

The first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52 are composed of a conductive member such as a coil.

The first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52 cancel the stress-induced anisotropy M10 generated when the magnetoresistive element 10 is deformed by the current flowing through the first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52. Generates a canceling magnetic field. The stress-induced anisotropy M10 is canceled by the combined magnetic field M11 of the first canceling magnetic field and the second canceling magnetic field.

The current control unit 55 adjusts the amount of current flowing through the first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52 so that the output value of the full bridge circuit becomes zero when the magnetoresistive element 10 is deformed. The detection accuracy is determined by calculating the direction of the external force applied to the deflection region 4 and the amount of distortion of the magnetoresistive element 10 based on the amount of current flowing through the first cancel magnetic field generation unit 51 and the second cancel magnetic field generation unit 52. Can be improved.

(Embodiment 10)
FIG. 48 is a schematic plan view showing a non-deformed state in which the diaphragm portion is not deformed in the sensor according to the tenth embodiment. The sensor 100I according to the tenth embodiment will be described with reference to FIG. 48.

As shown in FIG. 48, the sensor 100I according to the tenth embodiment has a different magnetization direction of the reference layer when compared with the sensor 100 according to the first embodiment. The other configurations are almost the same.

In each magnetoresistive element 10, the magnetization direction of the reference layer is 180 degrees different from that of the first embodiment. As a result, the angles θ2 and θ3 are different from each other as compared with the first embodiment.

In the tenth embodiment, in the state where the diaphragm portion 3 is not deformed, that is, when no external force is applied to the deflection region 4, the first magnetoresistive element 11, the second magnetoresistive element 12, and the third magnetism In each of the resistance element 13 and the fourth magnetoresistive element 14, the counterclockwise angle θ1 from the reference direction to the magnetization direction of the free layer (the direction in which the magnetization of the free layer is directed by the bias magnetic field) is 135 degrees ± 5. Degree.

In a state where no external force is applied to the deflection region 4, the counterclockwise angle θ2 from the reference direction to the magnetization direction of the reference layer 24 in the first magnetoresistive element 11 and the fourth magnetoresistive element 14 is 225. Degree ± 5 degrees.

In a state where no external force is applied to the deflection region 4, the counterclockwise angle θ3 from the reference direction to the magnetization direction of the reference layer 24 in the second magnetoresistive element 12 and the third magnetoresistive element 13 is 45. Degree ± 5 degrees.

Even with such a configuration, the sensor 100I according to the tenth embodiment has the same effect as the sensor 100 according to the first embodiment.

Also in the second to ninth embodiments, the direction of the magnetization direction of the reference layer may be rotated by 180 degrees. That is, the angles θ2 and θ3 in the above-described 10th embodiment may be applied to the second to ninth embodiments as well.

(Embodiment 11)
FIG. 49 is a diagram showing a strain detection sensor according to the tenth embodiment. The strain detection sensor 150 according to the tenth embodiment will be described with reference to FIG. 49.

The strain detection sensor 150 according to the tenth embodiment includes the sensor 100 according to the first embodiment, a base portion 110, and a cover portion 120.

The base portion 110 has a plate-like shape and has a first main surface 110a and a second main surface 110b that are in a front-to-back relationship with each other. The base portion 110 is provided with a through hole 111. The base portion 110 is made of, for example, a substrate made of a material combining resin and glass fiber such as a glass epoxy substrate, a low temperature co-fired ceramics (LTCC) multilayer substrate, or alumina. A substrate or the like made of a ceramic material can be adopted.

The sensor 100 is arranged on the first main surface 110a. The sensor 100 is arranged so that the cavity 5 communicates with the through hole 111 and the deflection region 4 faces the through hole 111.

The cover portion 120 is provided so as to cover the sensor 100 at a distance from the sensor 100 on the first main surface 110a side. The cover portion 120 is joined to the first main surface 110a without a gap in order to seal the space between the sensor 100 and the cover portion 120.

The cover portion 120 is made of a metal material or a resin material. The cover portion 120 may be formed by cutting or pressing a member made of the above material, or may be formed by molding.

In the strain detection sensor 150 having the above configuration, the space inside the sensor 100 (the space between the sensor 100 and the first main surface 110a) and the space outside the sensor 100 (between the sensor 100 and the cover portion 120). Space) and is separated. When an external force is applied to the deflection region 4 of the sensor 100 by a sound wave or the like passing through the through hole 111, the magnetoresistive element arranged in the deflection region 4 is distorted. A voltage corresponding to the amount of distortion of the magnetoresistive element is output from the sensor 100. As described above, in the distortion detection sensor 150, distortion can be detected with high sensitivity by measuring the output.

(Embodiment 12)
FIG. 50 is a diagram showing a pressure sensor according to the eleventh embodiment. The pressure sensor 200 according to the eleventh embodiment will be described with reference to FIG. 50. Note that FIG. 50 shows a state in which the base portion 210 is bent due to stress acting on the base portion 210.

As shown in FIG. 50, the pressure sensor 200 according to the eleventh embodiment includes the sensor 100 according to the first embodiment, a base portion 210, and a sealing portion 220.

The base portion 210 has a plate-like shape. The sensor 100 is arranged on the base portion 210. The sensor 100 is sealed on the base 210 by the sealing 220.

When stress (pressure) acts on the base portion 210 and the base portion 210 is distorted, the pressure also acts on the sensor 100 arranged on the base portion 210. As a result, the deflection region 4 of the sensor 100 is distorted, and the magnetoresistive element arranged on the deflection region is also distorted. A voltage corresponding to the amount of distortion of the magnetoresistive element is output from the sensor 100. As described above, in the pressure sensor 200, the pressure applied to the base portion can be detected with high sensitivity by measuring the output.

(Embodiment 13)
FIG. 51 is a diagram showing a mobile information terminal provided with the microphone according to the twelfth embodiment. The microphone 300 according to the twelfth embodiment will be described with reference to FIG. 51.

As shown in FIG. 51, the microphone 300 provided with the sensor 100 according to the first embodiment is incorporated in the mobile information terminal 400. The diaphragm portion 3 of the sensor 100 provided on the microphone 300 is substantially parallel to the surface of the mobile information terminal 400 on which the display portion 410 is provided. The arrangement of the sensor 100 can be changed as appropriate.

By providing the sensor 100 in the microphone 300, it is possible to detect sound with high sensitivity in a wide frequency band.

The microphone 300 may be incorporated into an IC recorder, a pin microphone, or the like in addition to the mobile information terminal 400.

In the above-described embodiments 11 to 13, the case where the strain detection sensor 150, the pressure sensor 200, and the microphone 300 include the sensor 100 according to the first embodiment has been described as an example, but the present invention is not limited thereto. Any of the sensors according to the first to tenth embodiments may be provided.

As mentioned above, the embodiments disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is indicated by the claims and includes all modifications within the meaning and scope equivalent to the claims.

1 substrate, 2 base, 3 diaphragm, 4 deflection area, 4A 1st area, 4B 2nd area, 4a slit, 5 cavity, 10 magnetoresistive element, 11th magnetoresistive element, 12th second magnetoresistive element, 13th magnetoresistive element, 14th magnetoresistive element, 20 lower electrode layer, 21 pinning layer, 22 pin layer, 23 magnetic coupling layer, 24 reference layer, 25 tunnel barrier layer, 26 free layer, 27 separation layer, 28 Bias layer, 29 upper electrode layer, 31 metal wiring, 41 1st side, 42 2nd side, 43 3rd side, 44 4th side, 51 1st cancel magnetic field generator, 52 2nd cancel magnetic field generation Part, 53 1st insulating layer, 54 2nd insulating layer, 55 current control part, 61 substrate, 62 film part, 63 lower electrode film, 64 laminated film, 65 upper electrode film, 66 insulating film, 67 passion film, 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100X sensor, 110 base part, 110a first main surface, 110b second main surface, 111 through hole, 120 cover part, 150 distortion detection sensor, 200 pressure sensor, 210 base part, 220 sealing part, 300 microphone, 400 mobile information terminal, 410 display part.

Claims

A substrate with a deflection area and
A plurality of magnetoresistive elements arranged in the deflection region so that each center of gravity is along the outer edge of the deflection region is provided.
The plurality of magnetoresistive elements include one or more first magnetoresistive elements and one or more second magnetoresistive elements constituting the first half-bridge circuit, and one or more members constituting the second half-bridge circuit. Includes a third magnetoresistive element and one or more fourth magnetoresistive elements
A full bridge circuit is composed of the first half bridge circuit and the second half bridge circuit.
The first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element each have a free layer whose magnetization direction changes according to the deflection of the deflection region and magnetization. It has a reference layer with a fixed direction and a tunnel barrier layer arranged between the free layer and the reference layer.
A bias magnetic field is applied to the free layer so that the magnetization direction faces a predetermined direction in a state where no external force is applied to the deflection region.
In each of the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element, the first magnetoresistive element, the second magnetoresistive element, and the third magnetism A straight line orthogonal to the shortest virtual straight line connecting each center of gravity of the resistance element and the fourth magnetic resistance element with the outer edge of the deflection region and passing through the center of gravity is set as a reference line.
In the reference line, when the intersection of the virtual straight line and the outer edge is viewed from the center of gravity in front and the direction from the center of gravity to the right is set as the reference direction.
In each of the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element, in a state where no external force is applied to the deflection region, from the reference direction. The counterclockwise angle to the direction in which the free layer is magnetized by the bias magnetic field is 135 degrees ± 5 degrees.
In the first magnetoresistive element and the fourth magnetoresistive element, the counterclockwise angle from the reference direction to the magnetization direction of the reference layer is 45 degrees ± 5 degrees.
A sensor having a counterclockwise angle of 225 degrees ± 5 degrees from the reference direction to the magnetization direction of the reference layer in the second magnetoresistive element and the third magnetoresistive element.
A substrate with a deflection area and
Each center of gravity is provided with a plurality of magnetoresistive elements arranged in the deflection region so as to be along the outer edge of the deflection region.
The plurality of magnetoresistive elements include one or more first magnetoresistive elements and one or more second magnetoresistive elements constituting the first half-bridge circuit, and one or more members constituting the second half-bridge circuit. Includes a third magnetoresistive element and one or more fourth magnetoresistive elements
A full bridge circuit is composed of the first half bridge circuit and the second half bridge circuit.
The first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element each have a free layer whose magnetization direction changes according to the deflection of the deflection region and magnetization. It has a reference layer with a fixed direction and a tunnel barrier layer sandwiched between the free layer and the reference layer.
A bias magnetic field is applied to the free layer so that the magnetization direction faces a predetermined direction in a state where no external force is applied to the deflection region.
In each of the first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element, the first magnetoresistive element, the second magnetoresistive element, and the third magnetism A straight line orthogonal to the shortest virtual straight line connecting each center of gravity of the resistance element and the fourth magnetic resistance element with the outer edge of the deflection region and passing through the center of gravity is set as a reference line.
In the reference line, when the intersection of the virtual straight line and the outer edge is viewed from the center of gravity in front and the direction from the center of gravity to the right is set as the reference direction.
In a state where no external force is applied to the deflection region, the clockwise angle from the reference direction to the direction in which the magnetization of the free layer is directed by the bias magnetic field is the first magnetoresistive element and the second magnetoresistive sensor. It is 135 degrees ± 5 degrees in each of the element, the third magnetoresistive element, and the fourth magnetoresistive element.
In the first magnetoresistive element and the fourth magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 225 degrees ± 5 degrees.
In the second magnetoresistive element and the third magnetoresistive element, the clockwise angle from the reference direction to the magnetization direction of the reference layer is 45 degrees ± 5 degrees.
The first magnetoresistive element, the second magnetoresistive element, the third magnetoresistive element, and the fourth magnetoresistive element have a bias layer for applying the bias magnetic field to the free layer and the bias layer, respectively. The sensor according to claim 1 or 2, further comprising a separation layer arranged between the free layer and the free layer.
The sensor according to any one of claims 1 to 3, wherein the free layer has a disk shape.
The free layer has a magnetized vortex structure and has a magnetized vortex structure.
The sensor according to claim 4, wherein the strength of the bias magnetic field applied to the free layer is larger than the strength of the exchange coupling magnetic field acting between the free layer and the reference layer.
4 or claim 4, wherein the disk diameter of the free layer in the first magnetoresistive element and the second magnetoresistive element is different from the disk diameter of the free layer in the third magnetoresistive element and the fourth magnetoresistive element. The sensor according to 5.
The invention according to any one of claims 1 to 6, wherein the sensitivities of the first magnetoresistive element and the second magnetoresistive element and the sensitivities of the third magnetoresistive element and the fourth magnetoresistive element are different from each other. Sensor.
The sensor according to any one of claims 1 to 7, wherein the deflection region is provided with a slit for dividing the deflection region into a plurality of parts in the circumferential direction.
The deflection region includes a first region and a second region separated from each other.
The one or more first magnetoresistive elements and the one or more second magnetoresistive elements are arranged in the first region.
In the second region, the one or more third magnetoresistive elements and the one or more fourth magnetoresistive elements are arranged.
The sensor according to any one of claims 1 to 7, wherein the resonance frequency of the first region and the resonance frequency of the second region are different from each other.
The deflection region includes a first region and a second region separated from each other.
The one or more first magnetoresistive elements and the one or more second magnetoresistive elements are arranged in the first region.
In the second region, the one or more third magnetoresistive elements and the one or more fourth magnetoresistive elements are arranged.
The sensor according to any one of claims 1 to 8, wherein the area of the first region and the area of the second region are different from each other.
When either the output from the first half-bridge circuit or the output from the second half-bridge circuit is saturated, the output from the first half-bridge circuit and the output from the second half-bridge circuit The sensor according to claim 9 or 10, wherein the other of the outputs is used.
A first cancel magnetic field generator and a second cancel magnetic field generator that generate a cancel magnetic field that cancels the stress-induced anisotropy that appears when an external force is applied to the deflection region.
The sensor according to any one of claims 1 to 11, further comprising a first cancel magnetic field generation unit and a current control unit that controls a current flowing through the second cancel magnetic field generation unit.
A distortion detection sensor including the sensor according to any one of claims 1 to 12.
A pressure sensor including the sensor according to any one of claims 1 to 12.
A microphone provided with the sensor according to any one of claims 1 to 12.