Patent Publication Number: US-2015082894-A1

Title: Pressure sensor and pressure sensor manufacturing method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2013-197553, filed on Sep. 24, 2013; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a pressure sensor and a pressure sensor manufacturing method. 
     BACKGROUND 
     In a capacitance change type pressure sensor, an overall diaphragm becomes a part of an electrode. Thus, the sensitivity of the pressure sensor is proportional to the area of a diaphragm film. On the other hand, in the case of a resistance change type pressure sensor, by increasing the number of sensing elements on the diaphragm film without change of the area of the diaphragm film, it is possible to increase the sensitivity of the pressure sensor and thus, it is desirable to increase the sensitivity of the pressure sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view illustrating a pressure sensor according to a first embodiment; 
         FIGS. 2A to 2D  are schematic plan views illustrating the film part of the pressure sensor according to the first embodiment; 
         FIG. 3  is a schematic perspective view illustrating a sensing element of the embodiment; 
         FIGS. 4A and 4B  are schematic perspective views illustrating another sensing element of the embodiment; 
         FIGS. 5A to 5D  are schematic perspective views illustrating the sensing element used for the pressure sensor according to the embodiment; 
         FIG. 6  is a schematic perspective view illustrating another sensing element used in the embodiment; 
         FIGS. 7A and 7B  are schematic plan views illustrating a case where the sensing element has shape isotropy; 
         FIGS. 8A and 8B  are schematic plan views illustrating a case where the sensing element has shape anisotropy; 
         FIGS. 9A and 9B  are schematic plan views illustrating a case where the sensing element has shape isotropy; 
         FIGS. 10A and 10B  are schematic diagrams illustrating a case where the sensing element has shape anisotropy; 
         FIGS. 11A to 11C  are schematic diagrams illustrating an operation of the pressure sensor according to the embodiment; 
         FIGS. 12A to 12C  are schematic plan views illustrating change in magnetization with respect to stress; 
         FIGS. 13A to 13C  are schematic plan views illustrating change in magnetization with respect to stress; 
         FIGS. 14A to 14C  are schematic plan views illustrating change in magnetization with respect to stress; 
         FIG. 15  is a flowchart illustrating a method for manufacturing a pressure sensor according to a second embodiment; 
         FIGS. 16A to 16E  are schematic process diagrams illustrating the method for manufacturing the pressure sensor; 
         FIGS. 17A to 17D  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 12A to 12C ; 
         FIGS. 18A and 18B  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 13A to 13C ; 
         FIGS. 19A to 19D  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 14A to 14C ; 
         FIG. 20  is a graph illustrating the relationship between the stress applied to the sensing element illustrated in  FIGS. 14A to 14C  and the electrical resistance; 
         FIG. 21  is a schematic cross-sectional view illustrating a manufacturing apparatus of a pressure sensor according to a third embodiment; 
         FIG. 22  is a schematic cross-sectional view illustrating another manufacturing apparatus of the pressure sensor according to the third embodiment; 
         FIG. 23  is a schematic plan view illustrating a microphone according to a fourth embodiment; 
         FIG. 24  is a schematic cross-sectional view illustrating the acoustic microphone according to a fifth embodiment; 
         FIGS. 25A and 25B  are schematic views illustrating the blood pressure sensor according to a sixth embodiment; and 
         FIG. 26  is a schematic plan view illustrating a touch panel according to a seventh embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, pressure sensor includes: a support unit; a substrate; and a plurality of sensing elements. The substrate is supported by the support unit and deformable. The plurality of sensing elements are provided on a part of the substrate. The sensing element includes a first magnetic layer, a second magnetic layer, and an intermediate layer. Magnetization of the first magnetic layer changes according to deformation of the substrate. Magnetization of the second magnetic layer is fixed. The intermediate layer is provided between the first magnetic layer and the second magnetic layer. A direction of the magnetization of the second magnetic layer of a first sensing element among the plurality of sensing elements is different from a direction of the magnetization of the second magnetic layer of a second sensing element among the plurality of sensing elements. 
     Various embodiments will be described hereinafter with reference to the accompanying drawings. 
     The drawings are schematic or conceptual; and the proportion of a portion, or the like is not necessarily the same as an actual proportion. Further, the dimensions or the proportion may be illustrated differently between the drawings, even for identical portions. 
     In the drawings and the specification of the application, components similar to those described in regard to a preceding drawing are marked with like reference numerals, and a detailed description thereof is omitted as appropriate. 
     First Embodiment 
       FIG. 1  is a schematic perspective view illustrating a pressure sensor according to a first embodiment. 
     In  FIG. 1 , for ease of description, insulating portions are not shown, and conductive portions are primarily shown. Further, for ease of description, only a part of plural sensing elements  50  is shown. 
     As illustrated in  FIG. 1 , a pressure sensor  310  includes a base unit (support unit)  71  and a sensor unit  72 . 
     The sensor unit  72  is provided on the base unit  71 . The sensor unit  72  includes a film part (substrate)  64 , a fixing part  67 , and the sensing elements  50 . 
     The film part  64  is a deformable film. The film part  64  is flexible, that is, can be bent in a direction perpendicular to film surfaces  64   a  and  64   b . The film part  64  is bent when external pressure is applied, and causes distortion in the sensing elements  50  provided thereon. The external pressure may be set as pressure due to sound waves, ultrasonic waves, pressing force or the like, for example. That is, the film part  64  is deformed if the external pressure is applied. 
     The film part  64  may be continuously formed on the outside from a portion that is bent by the external pressure. In the specification, a portion that has a predetermined film thickness thinner than that of a fixed end and that is bent by the external pressure is set as the film part  64 . 
     The film part  64  may be formed using an insulating material such as silicon oxide or silicon nitride, for example. Further, the film part  64  may be formed using a semiconductor material such as silicon, or using a metal material other than the semiconductor material. 
     The thickness size of the film part  64  may be set to 200 nm or more and 3 μm or less, for example. In such a case, preferably, the thickness size may be set to 300 nm or more and 1.5 μm or less, 
     As illustrated in  FIG. 1 , when a plane shape of the film part  64  is circular, the diameter size of the film part  64  may be set to 1 μm or more and 600 μm or less, for example. In such a case, preferably, the diameter size may be set to 60 μm or more and 600 μm or less. 
     The fixing part  67  fixes the film part  64  to the base unit  71 . The fixing part  67  has a thickness size thicker than that of the film part  64  so that the fixing part  67  is not easily bent even when the external pressure is applied. 
     The fixing part  67  may be provided at an equal interval on the peripheral edge of the film part  64  as illustrated in  FIG. 1 , or may be provided to surround the entire peripheral edge of the film part  64 . 
     Under the film part  64 , a hollow part  70  may be present. The hollow part  70  may be filled with gas such as air or inert gas, or may be filled with liquid. 
       FIGS. 2A to 2D  are schematic plan views illustrating the film part of the pressure sensor according to the first embodiment. 
     The film part  64  may have shape isotrophy, as illustrated in  FIG. 2A  or  2 C, or may have shape anisotrophy, as illustrated in  FIG. 2B  or  2 D. 
     An arrow illustrated in  FIG. 2A  represents an example of a magnetization  120   a  of a magnetization fixed layer. Here, the magnetization  120   a  of the magnetization fixed layer is not limited thereto. 
       FIG. 3  is a schematic perspective view illustrating a sensing element of the embodiment. 
       FIGS. 4A and 4B  are schematic perspective views illustrating another sensing element of the embodiment. 
     The sensing element  50  includes a magnetic layer  10 , a magnetic layer  20 , and an intermediate layer  30  provided between the magnetic layer  10  and the magnetic layer  20 . The intermediate layer  30  is a non-magnetic layer. Each of the plural sensing elements  50  on the film part  64  has the above-mentioned configuration. The magnetic layer  10  may be a first magnetic layer in which the magnetization is freely changed, or may be a second magnetic layer in which the magnetization is fixed. Similarly, the magnetic layer  20  may be the second magnetic layer, or may be the first magnetic layer. 
     The magnetic layer  10  of the sensing element  50  is connected to a first interconnect  57  (see  FIG. 1 ). The magnetic layer  20  of the sensing element  50  is connected to a second interconnect  58  (see  FIG. 1 ). A current flows in a direction from the magnetic layer  10  to the magnetic layer  20  or in a direction from the magnetic layer  20  to the magnetic layer  10 . 
     The first interconnect  57  and the second interconnect  58  extend outward from the film part  64  through an upper side of the fixing part  67  or an inner side of the fixing part  67 . 
     The sensing element  50  has shape anisotropy as illustrated in  FIG. 3  or  4 B, and may have shape isotropy as illustrated in  FIG. 4A . In the figures, a square is employed as an example of the shape of the element having isotropy, and a rectangle is employed as an example of the shape of the element having anisotropy. In the following description, as examples of the elements having isotropy and anisotropy, these shapes are employed. 
     The thickness size of the magnetic layer  10  and the magnetic layer  20  may be set 1 nm or more and 20 nm or less, for example. In such a case, it is favorable that the thickness size of the magnetic layer  10  and the magnetic layer  20  be set 2 nm or more and 6 nm or less. 
     Hereinafter, an example of the sensing element used for the pressure sensor according to the embodiment will be described. 
       FIGS. 5A to 5D  are schematic perspective views illustrating the sensing element used for the pressure sensor according to the embodiment. 
     Hereinafter, “material A/material B” represents a state in which a layer of material B is provided on a layer of material A. 
       FIG. 5A  is a schematic perspective view illustrating the sensing element used in the embodiment. 
     As illustrated in  FIG. 5A , a sensing element  50 A used in the embodiment includes a lower electrode E 1 , a foundation layer  150 , a pinning layer  160 , a second magnetization fixed layer  22 , a magnetic coupling layer  23 , a first magnetization fixed layer  21 , the intermediate layer  30 , a magnetization free layer  11 , a capping layer  170 , and an upper electrode E 2  arranged in order. 
     In the example, the magnetization free layer  11  corresponds to the first magnetic layer  10 , and the first magnetization fixed layer  21  corresponds to the second magnetic layer  20 . The sensing element  50 A is a bottom spin-valve type element. 
     The foundation layer  150  includes, for example, Ta/Ru. The thickness (the length in the Z-axis direction) of the Ta layer is, for example, 3 nm. The thickness of the Ru layer is, for example, 2 nm. 
     The pinning layer  160  includes, for example, an IrMn layer having a thickness of 7 nm. The second magnetization fixed layer  22  includes, for example, a Co 75 Fe 25  layer having a thickness of 2.5 nm. The magnetic coupling layer  23  includes, for example, an Ru layer having a thickness of 0.9 nm. 
     The first magnetization fixed layer  21  includes, for example, a Co 40 Fe 40 B 20  layer having a thickness of 3 nm. The intermediate layer  30  includes, for example, an MgO layer having a thickness of 1.6 nm. The magnetization free layer  11  includes, for example, Co 40 Fe 40 B 20  having a thickness of 4 nm. 
     The capping layer  170  includes, for example, Ta/Ru. The thickness of the Ta layer is, for example, 1 nm. The thickness of the Ru layer is, for example, 5 nm. 
     The lower electrode E 1  and the upper electrode E 2  include, for example, at least one selected from aluminum (Al), an aluminum copper alloy (Al—Cu), copper (Cu), silver (Ag) and gold (Au). A current can be caused to efficiently flow in the sensing element  50 A by using such a material that has a relatively small electrical resistance as the lower electrode E 1  and the upper electrode E 2 . 
     The lower electrode E 1  may have a structure in which at least one layer selected from Al, Al—Cu, Cu, Ag and Au is provided between a capping layer (not shown) and a foundation layer (not shown) for the lower electrode E 1 . For example, the lower electrode E 1  includes tantalum (Ta),/copper (Cu)/tantalum (Ta), or the like. For example, it is possible to improve adhesion between the film part  64  and the lower electrode E 1  by using Ta as the foundation layer for the lower electrode E 1 . Titanium (Ti), titanium nitride (TN) or the like may be used as the foundation layer for the lower electrode E 1 . 
     It is possible to prevent oxidization of the copper (Cu) or the like under the capping layer for the lower electrode E 1  by using Ta as the capping layer. Titanium (Ti), titanium nitride (TN) or the like may be used as the capping layer for the lower electrode E 1 . 
     The foundation layer  150  may include a stacked structure of a buffer layer (not shown) and a seed layer (not shown). For example, the buffer layer reduces the irregularity of the surfaces of the lower electrode E 1  and the film part  64 , and improves the crystallinity of the layers stacked on the buffer layer. For example, at least one selected from the group consisted of tantalum (Ta), titanium (Ti), vanadium (V), tungsten (W), zirconium (Zr), hafnium (Hf) and chrome (Cr) is used as the buffer layer. An alloy including at least one material selected from these materials may be used as the buffer layer. 
     It is favorable that the thickness of the buffer layer be 1 nm or more and 10 nm or less. It is more favorable that the thickness of the buffer layer be 1 nm or more and 5 nm or less. The buffering effect is lost when the thickness of the buffer layer is too thin. The thickness of the sensing element  50  becomes excessively thick when the thickness of the buffer layer is too thick. The seed layer may be formed on the buffer layer, and the seed layer may have a buffering effect. The buffer layer may be omitted. The buffer layer includes, for example, a Ta layer having a thickness of 3 nm. 
     The seed layer (not shown) controls the crystal orientation of the layers stacked on the seed layer. The seed layer controls the crystal grain size of the layers stacked on the seed layer. A metal or the like having a face-centered cubic (fcc) structure, a hexagonal close-packed (hcp) structure or a body-centered cubic (bcc) structure is used as the seed layer. 
     By using ruthenium (Ru) having an hcp structure, NiFe having an fcc structure, or Cu having an fcc structure as the seed layer, for example, the crystal orientation of the spin-valve film on the seed layer can have an fcc (111) orientation. The seed layer includes, for example, a Cu layer having a thickness of 2 nm or an Ru layer having a thickness of 2 nm. To improve the crystal orientation of the layers formed on the seed layer, it is favorable that the thickness of the seed layer be 1 nm or more and 5 nm or less. It is more favorable that the thickness of the seed layer be 1 nm and 3 nm or less. Thus, the function of the seed layer of improving the crystal orientation is sufficiently realized. On the other hand, for example, in a case where it is unnecessary to cause the layers formed on the seed layer to have a crystal orientation (for example, in a case where an amorphous magnetization free layer is formed), the seed layer may be omitted. For example, an Ru layer having a thickness of 2 nm is used as the seed layer. 
     The pinning layer  160  provides unidirectional anisotropy to a ferromagnetic layer formed on the pinning layer  160  to fix the magnetization. In the example illustrated in  FIG. 5A , the pinning layer  160  provides unidirectional anisotropy to a ferromagnetic layer of the second magnetization fixed layer  22  formed on the pinning layer  160  to fix the magnetization. The pinning layer  160  includes, for example, an antiferromagnetic layer. The pinning layer  160  includes, for example, at least one selected from the group consisted of Ir—Mn, Pt—Mn, Pd—Pt—Mn and Ru—Rh—Mn. The thickness of the pinning layer  160  is set appropriately to provide unidirectional anisotropy of sufficient strength. 
     In order to perform the fixing of the magnetization of the ferromagnetic layer being in contact with the pinning layer  160 , a heat treatment is performed while a magnetic field is applied. The magnetization of the ferromagnetic layer being in contact with the pinning layer  160  is fixed in a direction of the magnetic field applied in the heat treatment. An annealing temperature is set to be equal to or higher than a blocking temperature of an antiferromagnetic material used in the pinning layer  160 , for example. Further, when an antiferromagnetic layer including Mn is used, Mn may be diffused to a layer other than the pinning layer to reduce an MR change ratio. Accordingly, it is favorable to set the temperature to be equal to or lower than a temperature at which the diffusion of Mn occurs. For example, it is favorable to set the temperature to 200° C. or more and 500° C. or less. It is more favorable to set the temperature to 250° C. or more and 400° C. or less. 
     When Pt—Mn or Pd—Pt—Mn is used as the pinning layer  160 , it is favorable that the thickness of the pinning layer  160  be 8 nm or more and 20 nm or less. It is more favorable that the thickness of the pinning layer  160  be 10 nm or more and 15 nm or less. The pinning layer  160  that provides the directional anisotropy may be thinner in a case where IrMn is used as the pinning layer  160  than in a case where PtMn is used as the pinning layer  160 . In such a case, it is favorable that the thickness of the pinning layer  160  be 4 nm or more and 18 nm or less. It is more favorable that the thickness of the pinning layer  160  be 5 nm or more and 15 nm or less. The pinning layer  160  includes, for example, an Ir 22 Mn 78  layer having a thickness of 7 nm. In a case where the Ir 22 Mn 76  layer is used, a heat treatment of 320°-1H may be performed while a magnetic field of 10 KOe is applied, as a heat treatment condition in the magnetic field. In a case where a Pt 50 Mn 50  layer is used, a heat treatment of 320° C.-10H may be performed while a magnetic field of 10 KOe is applied, as a heat treatment condition in the magnetic field. 
     The second magnetization fixed layer  22  includes, for example, a Co x Fe 100-x  alloy (x being 0 at. % or more and 100 at. % or less), an Ni x Fe 100-x  alloy (x being 0 at. % or more and 100 at. % or less), or a material in which a non-magnetic element is added to these alloys. For example, at least one selected from the group consisted of Co, Fe and Ni is used as the second magnetization fixed layer  22 . An alloy including at least one material selected from these materials may be used as the second magnetization fixed layer  22 . 
     It is favorable that the thickness of the second magnetization fixed layer  22  be, for example, 1.5 nm or more and 5 nm or less. Thus, for example, it is possible to increase the strength of the unidirectional anisotropic magnetic field due to the pinning layer  160 , For example, it is possible to increase the strength of the antiferromagnetic coupling magnetic field between the second magnetization fixed layer  22  and the first magnetization fixed layer  21  through the magnetic coupling layer  23  formed on the second magnetization fixed layer  22 . It is favorable that the magnetic film thickness of the second magnetization fixed layer  22  (the product of a saturation magnetization Bs and a thickness t (Bs·t)) be substantially equal to the magnetic film thickness of the first magnetization fixed layer  21 . 
     In a thin film, the saturation magnetization of Co 40 Fe 40 B 20  is about 1.9 T (teslas). For example, in a case where a Co 40 Fe 40 B 20  layer having a thickness of 3 nm is used as the first magnetization fixed layer  21 , the magnetic film thickness of the first magnetization fixed layer  21  is 1.9 T×3 nm which is 5.7 Tnm. On the other hand, the saturation magnetization of Co 75 Fe 25  is about 2.1 T. The thickness of the second magnetization fixed layer  22  to obtain a magnetic film thickness that is equal to the above-mentioned magnetic film thickness is 5.7 Tnm/2.1 T, which is 2.7 nm. In such a case, it is favorable that the second magnetization fixed layer  22  include Co 75 Fe 25  having a thickness of about 2.7 nm. For example, a Co 75 Fe 25  layer having a thickness of 2.5 nm is used as the second magnetization fixed layer  22 . 
     In the sensing element  50 A, a synthetic pinned structure of the second magnetization fixed layer  22 , the magnetic coupling layer  23 , and the first magnetization fixed layer  21  is used. Instead, a single pinned structure made of one magnetization fixed layer may be used. In a case where the single pinned structure is used, for example, a Co 40 Fe 40 B 20  layer having a thickness of 3 nm is used as the magnetization fixed layer. The same material as the first magnetization fixed layer  21  to be described later may be used as the ferromagnetic layer used in the magnetization fixed layer of the single pinned structure. 
     The magnetic coupling layer  23  causes antiferromagnetic coupling to occur between the second magnetization fixed layer  22  and the first magnetization fixed layer  21 . The magnetic coupling layer  23  forms a synthetic pinned structure. For example, Ru is used as the magnetic coupling layer  23 . It is favorable that the thickness of the magnetic coupling layer  23  be 0.8 nm or more and 1 nm or less. A material other than Ru may be used as the magnetic coupling layer  23  as long as the material can cause sufficient antiferromagnetic coupling to occur between the second magnetization fixed layer  22  and the first magnetization fixed layer  21 . The thickness of the magnetic coupling layer  23  may be set to be a thickness of 0.8 nm or more and 1 nm or less that corresponds to the second peak (2nd peak) of Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling. Further, the thickness of the magnetic coupling layer  23  may be set to be a thickness of 0.3 nm or more and 0.6 nm or less that corresponds to the first peak (1st peak) of RKKY coupling. For example, Ru having a thickness of 0.9 nm is used as the magnetic coupling layer  23 . Thus, highly reliable coupling is obtained more stably. 
     The magnetic layer that is used in the first magnetization fixed layer  21  (the second magnetic layer  20 ) contributes directly to the MR effect. For example, a Co—Fe—B alloy is used as the first magnetization fixed layer  21 . Specifically, a (Co x Fe 100-x ) 100-y B y  alloy (x being 0 at. % or more and 100 at. % or less and y being 0 at. % or more and 30 at. % or less) may be used as the first magnetization fixed layer  21 . In a case where an amorphous alloy of (Co x Fe 100-x ) 100-y B y  is used as the first magnetization fixed layer  21 , for example, it is possible to suppress the fluctuation between the elements due to the crystal grains even in a case where the size of the sensing element  50 A is small. 
     The layer (e.g., a tunneling insulating layer (not shown)) that is formed on the first magnetization fixed layer  21  (the second magnetic layer  20 ) may be planarized. By planarizing the tunneling insulating layer, it is possible to reduce the defect density of the tunneling insulating layer. Thus, a higher MR change ratio is obtained with a lower resistance per area. For example, in a case where MgO is used as a material of the tunneling insulating layer, it is possible to improve the (100) orientation of the MgO layer formed on the tunneling insulating layer by using an amorphous alloy of (Co x Fe 100-x ) 100-y B y . A higher MR change ratio is obtained by improving the (100) orientation of the MgO layer. The (Co x Fe 100-x ) 100-y B y  alloy crystallizes the (100) plane of the MgO layer as a template in the annealing. Therefore, excellent crystal conformation between the MgO and (Co x Fe 100-x ) 100-y B y  alloy is obtained. A higher MR change ratio is obtained by obtaining excellent crystal conformation. 
     Instead of the Co—Fe—B alloy, for example, an Fe—Co alloy may be used as the first magnetization fixed layer  21  (the second magnetic layer  20 ). 
     The MR change ratio increases as the thickness of the first magnetization fixed layer  21  (the second magnetic layer  20 ) increases. A thinner first magnetization fixed layer  21  is favorable to obtain a larger fixed magnetization field. A trade-off relationship in the thickness of the first magnetization fixed layer  21  exists between the MR change ratio and the fixed magnetization field. In a case where the Co—Fe—B alloy is used as the first magnetization fixed layer  21 , it is favorable that the thickness of the first magnetization fixed layer  21  be 1.5 nm or more and 5 nm or less. It is more favorable that the thickness of the first magnetization fixed layer  21  be 2.0 nm or more and 4 nm or less. 
     Other than the materials described above, the first magnetization fixed layer  21  (the second magnetic layer  20 ) may include a Co 90 Fe 10  alloy having an fcc structure, Co having an hcp structure, or a Co alloy having an hcp structure. At least one selected from the group consisted of Co, Fe, and Ni may be used as the first magnetization fixed layer  21 . An alloy including at least one material selected from these materials may be used as the first magnetization fixed layer  21 . For example, a higher MR change ratio is obtained by using an FeCo alloy material having a bcc structure, a Co alloy including a cobalt composition of 50 at. % or more, or a material having a Ni composition of 50 at. % or more as the first magnetization fixed layer  21 . A Heusler magnetic alloy layer made of Co 2 MnGe, Co 2 FeGe, Co 2 MnSi, Co 2 FeSi, Co 2 MnAl, Co 2 FeAl, Co 2 MnGa 0.5 Ge 0.5 , Co 2 FeGa 0.5 Ge 0.5 , or the like may be used as the first magnetization fixed layer  21 . For example, a Co 40 Fe 40 B 20  layer having a thickness of 3 nm may be used as the first magnetization fixed layer  21 . 
     The intermediate layer  30  disconnects the magnetic coupling between the first magnetization fixed layer  21  and the magnetization free layer  11 . The intermediate layer  30  includes a metal, an insulator or a semiconductor. For example, Cu, Au, Ag or the like may be used as the metal. In a case where the metal is used as the intermediate layer  30 , the thickness of the intermediate layer  30  is, for example, about 1 nm or more and about 7 nm or less. For example, magnesium oxide (Mg—O, etc.), aluminum oxide (Al 2 O 3 , etc.), titanium oxide (Ti—O, etc.), zinc oxide (Zn—O, etc.), gallium oxide (Ga—O), or the like may be used as the insulator or the semiconductor. In a case where the insulator or the semiconductor is used as the intermediate layer  30 , the thickness of the intermediate layer  30  is, for example, about 0.6 nm or more and about 2.5 nm or less. 
     The material of the magnetization free layer  11  (the first magnetic layer  10 ) may include at least one of Fe, Co and Ni, or an alloy including at least one thereof. Further, the material may be a material in which an additional element is added to the above-mentioned material. 
     Further, B, Al, Si, Mg, C, Ti, V, Cr, Mn, Cu, Zn, Ga, Zr, Hf or the like may be added to the above-mentioned metal or alloy as an additional element or an ultrathin layer. 
     Further, a crystalline magnetic layer may be used, or instead, an amorphous magnetization free layer may be used. 
     Further, a magnetic layer of an oxide or a nitride may be used. 
     The magnetization free layer  11  (the first magnetic layer  10 ) is formed of a material having a large absolute value of a magnetostriction constant. In such a case, the absolute value of the magnetostriction constant may be changed according to the type of the material, the additional element or the like. Further, magnetic strain may be greatly changed according to the material and configuration of the non-magnetic layer formed adjacent to the magnetic layer, other than the magnetic material. The absolute value of the magnetostriction constant may be larger than 10 −2 , for example. In such a case, it is more favorable that the absolute value of the magnetostriction constant be larger than 10 −5 , for example. 
     As the absolute value of the magnetostriction constant increases, change in a magnetization direction due to a stress change may increase. 
     The magnetization free layer  11  (the first magnetic layer  10 ) may use a material having a positive magnetostriction constant, or may use a material having a negative magnetostriction constant. 
     The magnetization free layer  11  (the first magnetic layer  10 ) may include an alloy including at least one element selected from the group consisted of Fe, Co and Ni and boron (B). For example, the magnetization free layer  11  (the first magnetic layer  10 ) may include a Co—Fe—B alloy, an Fe—B alloy, an Fe—Co—Si—B alloy or the like. For example, the magnetization free layer  11  (the first magnetic layer  10 ) may include a Co 40 Fe 40 B 20  layer having a thickness of 4 nm. 
     The material of the magnetization free layer (the first magnetic layer) may include an FeCo alloy, an NiFe alloy or the like, for example. Alternatively, the material of the first magnetic layer and the second magnetic layer may include an Fe—Co—Si alloy, an Fe—Co—Si—B alloy, a Tb-M-Fe alloy (M being at least one selected from the group consisted of Sm, Eu, Gd, Dy, Ho and Er) indicating λs&gt;100 ppm, a Tb-M1-Fe-M2 alloy (M1 being at least one selected from the group consisted of Sm, Eu, Gd, Dy, Ho and Er, and M2 being at least one selected from the group consisted of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta), an Fe-M3-M4-B alloy (M3 being at least one selected from the group consisted of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta and M4 being at least one selected from the group consisted of Ce, Pr, Nd, Sm, Tb, Dy and Er), Ni, Fe—Al, or ferrite (Fe 3 O 4 , (FeCo) 3 O 4 , or the like). 
     The magnetization free layer  11  (the first magnetic layer  10 ) may have a multilayered structure. The magnetization free layer  11  (the first magnetic layer  10 ) may have, for example, a two-layer structure. In a case where a tunneling insulating layer of MgO is used as the intermediate layer  30 , it is favorable to provide a layer of a Co—Fe—B alloy on a contact interface with the intermediate layer  30 . Thus, a high magnetoresistance effect is obtained. In such a case, a layer of a Co—Fe—B alloy may be provided on the intermediate layer  30 ; and an Fe—Co—Si—B alloy, an Fe—Ga alloy having a large Xs, an Fe—Co—Ga alloy, a Tb-M-Fe alloy (M being at least one selected from the group consisted of Sm, Eu, Gd, Dy, Ho and Er), a Tb-M1-Fe-M2 alloy (M1 being at least one selected from the group consisted of Sm, Eu, Gd, Dy, Ho and Er, and M2 being at least one selected from the group consisted of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta), an Fe-M3-M4-B ahoy (M3 being at least one selected from the group consisted of Ti, Cr, Mn, Co, Cu, Nb, Mo, W and Ta, and M4 being at least one selected from the group consisted of Ce, Pr, Nd, Sm, Tb, Dy and Er), Ni, Fe—Al, or ferrite (Fe 3 O 4 , (FeCo) 3 O 4 , or the like) may be formed on the layer of the Co—Fe—B alloy. For example, the magnetization free layer  11  includes Co 40 Fe 40 B 20 /Fe 80 Ga 20 . The thickness of the Co 40 Fe 40 B 20 , is, for example, 2 nm. The thickness of the Fe 80 Ga 20  is, for example, 4 nm. For example, λs is greater than 100 ppm. 
     The capping layer  170  protects the layers provided under the capping layer  170 . The capping layer  170  includes, for example, plural metal layers. The capping layer  170  includes, for example, a two-layer structure of a Ta layer and an Ru layer (Ta/Ru). The thickness of the Ta layer is, for example, 1 nm, and the thickness of the Ru layer is, for example, 5 nm. Other metal layers may be provided instead of the Ta layer or the Ru layer as the capping layer  170 , The configuration of the capping layer  170  is arbitrary. The capping layer  170  may include, for example, a non-magnetic material. Other materials may be used as the capping layer  170  as long as the layers provided under the capping layer  170  can be protected. 
       FIG. 5B  is a schematic perspective view illustrating another sensing element used in the embodiment. As illustrated in  FIG. 5B , the sensing element  50 B used in the pressure sensor according to the embodiment includes the lower electrode E 1 , the foundation layer  150 , the magnetization free layer  11 , the intermediate layer  30 , the first magnetization fixed layer  21 , the magnetic coupling layer  23 , the second magnetization fixed layer  22 , the pinning layer  160 , the capping layer  170 , and the upper electrode E 2  arranged in order. 
     In the example, the magnetization free layer  11  corresponds to the first magnetic layer  10 , and the first magnetization fixed layer  21  corresponds to the second magnetic layer  20 , The sensing element  50 B is a top spin-valve type element, Each of the layers included in the sensing element  50 B may include the material described in the sensing element  50 A, for example. 
       FIG. 5C  is a schematic perspective view illustrating another sensing element used in the embodiment. As illustrated in  FIG. 5C , the sensing element  50 C used in the pressure sensor according to the embodiment includes the lower electrode E 1 , the foundation layer  150 , a lower pinning layer  161 , a lower second magnetization fixed layer  22   a , a lower magnetic coupling layer  23   a , a lower first magnetization fixed layer  21   a , an intermediate layer  31 , the magnetization free layer  11 , an upper intermediate layer  32 , an upper first magnetization fixed layer  21   b , an upper magnetic coupling layer  23   b , an upper second magnetization fixed layer  22   b , an upper pinning layer  162 , the capping layer  170 , and the upper electrode E 2  arranged in order. 
     The magnetization free layer  11  corresponds to the first magnetic layer  10 , and at least one of the lower first magnetization fixed layer  21   a  and the upper first magnetization fixed layer  21   b  corresponds to the second magnetic layer  20 . In the sensing element  50 A and the sensing element SOB described above, the magnetization fixed layer is disposed at one surface of the magnetization free layer. In the sensing element  50 C, the magnetization free layer is disposed between two magnetization fixed layers. The sensing element  50 C is a dual spin-valve type element. Each of the layers included in the sensing element  50 C may include the material described in the sensing element  50 A, for example. 
       FIG. 5D  is a schematic perspective view illustrating another sensing element used in the embodiment. As illustrated in  FIG. 5D , the sensing element  50 D used in the pressure sensor according to the embodiment includes the lower electrode E 1 , the foundation layer  150 , the pinning layer  160 , the magnetization fixed layer  24 , the intermediate layer  30 , the magnetization free layer  11 , the capping layer  170 , and the upper electrode E 2  arranged in order. 
     The magnetization free layer  11  corresponds to the first magnetic layer  10 , and the magnetization fixed layer  24  corresponds to the second magnetic layer  20 . In the sensing elements  50 A and  50 B described above, a structure that uses the second magnetization fixed layer  22 , the magnetic coupling layer  23 , and the first magnetization fixed layer  21  is used. In the sensing element  50 D, a single pinned structure that uses the single magnetization fixed layer  24  is used. Each of the layers included in the sensing element  50 D may include the material described in the sensing element  50 A, for example. 
       FIG. 6  is a schematic perspective view illustrating another sensing element used in the embodiment. 
     As illustrated in  FIG. 6 , an insulating layer  91  is provided in a sensing element  50 E. That is, two insulating layers  91  (insulating portions) that are separated from each other are provided between the lower electrode E 1  and the upper electrode E 2 , and the sensing element  50 A is disposed between the two insulating layers  91 . The sensing element  50 A is disposed between the lower electrode E 1  and the upper electrode E 2 . In the case of the sensing element  50 A, the stacked body includes the foundation layer  150 , the pinning layer  160 , the second magnetization fixed layer  22 , the magnetic coupling layer  23 , the first magnetization fixed layer  21 , the intermediate layer  30 , the magnetization free layer  11 , and the capping layer  170 . In other words, the insulating layers  91  are provided to face the side walls of the sensing element  50 A. 
     The insulating layers  91  may include, for example, aluminum oxide (e.g., Al 2 O 3 ), silicon oxide (e.g., SiO 2 ), or the like. It is possible to suppress a leak current around the stacked body (in the example, the sensing element  50 A) by the insulating layers  91 , The insulating layers  91  may be applied to any of the sensing elements  50 A to  50 D. 
     In the sensing element  50 , an “inverse-magnetostriction effect” acquired in the ferromagnet and an “MR effect” occurred in the sensing element  50  are used. The “inverse-magnetostriction effect” is obtained in the ferromagnetic layer used in the magnetization free layer. The “MR effect” occurs in the stacked film of the first magnetic layer, the intermediate layer, and the second magnetic layer. 
     The “inverse-magnetostriction effect” is a phenomenon in which the magnetization of a ferromagnet is changed by strain that occurs in the ferromagnet. In other words, when stress is applied to the sensing element  50 , the magnetization direction of the first magnetic layer that is the magnetization free layer changes. As a result, the relative angle between the magnetization of the first magnetic layer and the magnetization of the second magnetic layer changes. The “MR effect” is a phenomenon in which when an external magnetic field is applied in a stacked film having a magnet, the value of electrical resistance in the stacked film is changed by the change of the magnetization of the magnet. The MR effect includes, for example, a giant magnetoresistance (GMR) effect, a tunneling magnetoresistance (TMR) effect, or the like. As a current flows in the sensing element  50 , the change of the relative angle of the magnetization direction is read as the resistance change, so that the MR effect occurs. For example, the relative angle between the magnetization direction of the first magnetic layer that is the magnetization free layer of the sensing element  50  and the magnetization direction of the second magnetic layer is changed based on the strain applied to the sensing element  50 . Here, the MR effect occurs due to the inverse-magnetostriction effect. When the resistance of a low resistance state is represented as R and variation of the electrical resistance changed by the MR effect is represented as ΔR, ΔR/R represents “MR change ratio”. 
     In a case where the ferromagnetic material used in the magnetization free layer has a positive magnetostriction constant, the direction of the magnetization changes so that the angle between the direction of the magnetization and the direction of a tensile strain becomes small and the angle between the direction of the magnetization and the direction of a compressive strain becomes large. In a case where the ferromagnetic material of the magnetization free layer has a negative magnetostriction constant, the direction of the magnetization changes so that the angle between the direction of the magnetization and the direction of the tensile strain becomes large and the angle between the direction of the magnetization and the direction of the compressive strain becomes small. 
     In a case where a combination of the materials of the stacked body of the magnetization free layer, the intermediate layer, and a reference layer (for example, magnetization fixed layer) has a positive magnetostriction constant, the electrical resistance decreases in a case where the relative angle between the magnetization free layer and the magnetization fixed layer is small. In a case where the combination of the materials of the stacked body of the magnetization free layer, the intermediate layer and the reference layer (for example, magnetization fixed layer) has a negative magnetostriction constant, the electrical resistance increases in a case where the relative angle between the magnetization free layer and the magnetization fixed layer is small. 
       FIGS. 7A and 7B  are schematic plan views illustrating a case where the sensing element has shape isotropy. 
       FIG. 7A  is a schematic plan view illustrating a disposition example of the sensing element  50  on the film part  64  of the pressure sensor  310  according to the first embodiment. 
     In  FIG. 7A , the circle illustrated in  FIG. 2A  is employed as a shape example of the film surface  641 . Further, a shape that surrounds the entirety of the film part  64  is employed as an example of the shape of the fixing part  67 . The plural sensing elements  50  are disposed along a boundary  65  (an edge portion  64   c  of the film part  64 ; see  FIG. 1 ) between the film part  64  and the fixing part  67 , In other words, the plural sensing elements  50  are disposed along a peripheral portion  70   a  (see  FIG. 1 ) of the hollow part  70 . In  FIG. 7A , the sensing elements  50  may be disposed along the boundary  65  at an equal interval, but the sensing elements  50  may not be disposed at an equal interval. 
     The area of the sensing element  50  is sufficiently smaller than that of the film part  64 , The length of one side of the sensing element  50  may be 0.5 μm or more and 20 μm or less. 
       FIG. 7B  is a schematic plan view illustrating a positional relationship between the boundary  65  between the film part  64  and the fixing part  67 , and the sensing element  50 . 
     The plural sensing elements  50  are disposed so that an angle formed by a line  50   d  connecting a centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and one axis  50   a  (one side in the example) of the sensing element  50  is within a difference of 5° between at least two sensing elements among the plural sensing elements  50 . In the example illustrated in  FIGS. 7A and 7B , the angle formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the one axis  50   a  of the sensing element  50  is parallel (0° or 180°). As illustrated in  FIGS. 7A and 7B , the number of the sensing elements  50  in which the difference of the angles formed by the lines  50   d  connecting the centroids  53  of the sensing elements  50  and the boundary  65  in the shortest distance and the one axes  50   a  of the sensing elements  50  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 . For example, the number of the sensing elements  50  may be three or more disposed in the circumferential direction of the film part  64 . 
     Arrows illustrated in  FIGS. 7A and 7B  represent an example of the magnetization  120   a  of the magnetization fixed layer. An angle  205  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the magnetization  120   a  is within a difference of 5° between at least two sensing elements among the plural sensing elements  50 . In the example illustrated in  FIGS. 7A and 7B , the angle  205  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the magnetization  120   a  is 90°, As illustrated in  FIGS. 7A and 7B , the number of the plural sensing elements  50  in which the difference of the angles  205  formed by the lines  50   d  connecting the centroids  53  of the sensing elements  50  and the boundary  65  in the shortest distance and the magnetizations  120   a  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 . For example, the number of the sensing elements  50  may be three or more disposed in a row in the circumferential direction of the film part  64 . Here, the magnetization  120   a  of the magnetization fixed layer is not limited thereto. 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance. 
       FIGS. 8A and 8B  are schematic plan views illustrating a case where the sensing element has shape anisotropy. 
       FIG. 8A  is a schematic plan view illustrating a disposition example of the sensing elements  50  on the film part  64  of the pressure sensor  310  according to the first embodiment. 
     In  FIG. 8A , the circle illustrated in  FIG. 2A  is employed as a shape example of the film surface  64 . Further, a shape that surrounds the entirety of the film part  64  is employed as an example of the shape of the fixing part  67 . The plural sensing elements  50  are disposed along the boundary  65  between the film part  64  and the fixing part  67 . In  FIG. 8A , the sensing elements  50  may be disposed along the boundary  65  at an equal interval, but the sensing elements  50  may not be disposed at an equal interval. 
       FIG. 8B  is a schematic plan view illustrating a positional relationship between the boundary  65  between the film part  64  and the fixing part  67 , and the sensing element  50 . 
     The plural sensing elements  50  are disposed so that an angle  206  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and a long axis  50   b  of the sensing element  50  is within a difference of 5° between at least two sensing elements among the plural sensing elements  50 . In the example illustrated in  FIGS. 8A and 8B , the number of the plural sensing elements  50  in which the difference of the angles  206  formed by the lines  50   d  connecting the centroids  53  of the sensing elements  50  and the boundary  65  in the shortest distance and the long axes  50   b  of the sensing elements  50  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 , For example, the number of the sensing elements  50  may be three or more disposed in a row in the circumferential direction of the film part  64 . 
     Arrows illustrated in  FIGS. 8A and 8B  represent an example of the magnetization  120   a  of the magnetization fixed layer. The angle  205  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the magnetization  120   a  is within a difference of 5° between at least two sensing elements of the plural sensing elements  50 . In the example illustrated in  FIGS. 8A and 8B , the number of the sensing elements  50  in which the difference of the angles  205  formed by the lines  50   d  connecting the centroids  53  of the sensing elements  50  and the boundary  65  in the shortest distance and the magnetizations  120   a  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 , For example, the number of the plural sensing elements  50  may be three or more disposed in a row in the circumferential direction of the film part  64 , Here, the magnetization  120   a  of the magnetization fixed layer is not limited thereto. 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance. 
       FIGS. 9A and 9B  are schematic plan views illustrating a case where the sensing element has shape isotropy. 
     In  FIGS. 9A and 9B , the circle illustrated in  FIG. 2A  is employed as a shape example of the film surface  64 . Further, a shape that surrounds the entirety of the film part  64  is employed as an example of the shape of the fixing part  67 . 
       FIG. 9A  is a schematic plan view illustrating a line  50   e  connecting the centroid  53  of the sensing element  50  on the film part  64  of the pressure sensor  310  according to the first embodiment and a centroid  68  of the film part  64 . For ease of description, the number of elements  50  shown in the figure is reduced. Further, in  FIG. 9A , the elements  50  are disposed symmetrically with respect to the centroid  68 , but may not be disposed symmetrically with respect to the centroid  68 . The plural sensing elements  50  are disposed so that an angle formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 , and one axis  50   a  of the sensing element  50  is within a difference of 5° between at least two sensing elements among the plural sensing elements  50 . In the example illustrated in  FIGS. 9A and 9B , the angle formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64  and the one axis  50   a  of the sensing element  50  is parallel (0° or 180°). As illustrated in  FIGS. 9A and 9B , the number of the sensing elements  50  in which the difference of the angles formed by the lines  50   e  connecting the centroids  53  of the sensing elements  50  and the centroid  68  of the film part  64 , and the one axes  50   a  of the sensing elements  50  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 . For example, the number of the sensing elements  50  may be three or more disposed in the circumferential direction of the film part  64 . 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 . 
       FIG. 9B  is a schematic plan view illustrating an angle  207  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer of the sensing element  50 . 
     The plural sensing elements  50  are disposed so that the angle  207  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer is within a difference of 5° between at least two sensing elements of the plural sensing elements  50  on the film part  64 . In the example illustrated in  FIGS. 9A and 9B , the angle  207  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer is 90°, As illustrated in  FIGS. 9A and 9B , the number of the plural sensing elements  50  in which the difference of the angles  207  formed by the lines  50   e  connecting the centroids  53  of the sensing elements  50  and the centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be three or more disposed in a row in the circumferential direction of the film part  64 . 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 . 
       FIGS. 10A and 10B  are schematic diagrams illustrating a case where the sensing element has shape anisotropy. 
     In  FIGS. 10A and 10B , the circle illustrated in  FIG. 2A  is employed as a shape example of the film surface  64 , Further, a shape that surrounds the entirety of the film part  64  is employed as an example of the shape of the fixing part  67 . 
       FIG. 10A  is a schematic plan view illustrating the line  50   e  connecting the centroid  53  of the sensing element  50  on the film part  64  of the pressure sensor  310  according to the first embodiment and the centroid  68  of the film part  64 . For ease of description, the number of elements  50  in the figure is reduced. Further, in  FIG. 10A , the elements  50  are disposed symmetrically with respect to the centroid  68 , but may not be disposed symmetrically with respect to the centroid  68 . The plural sensing elements  50  are disposed so that an angle  208  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 , and the long axis  50   b  of the sensing element  50  is within a difference of 5° between at least two sensing elements of the plural sensing elements  50  on the film part  64 . In the example illustrated in  FIGS. 10A and 10B , the number of the plural sensing elements  50  in which the difference of the angles  208  formed by the lines  50   e  connecting the centroids  53  of the sensing elements  50  and the centroid  68  of the film part  64 , and the long axes  50   b  of the sensing elements  50  is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 . For example, the number of the sensing elements  50  may be three or more disposed in a row in the circumferential direction of the film part  64 . 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 . 
       FIG. 10B  is a schematic plan view illustrating the angle  207  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer of the sensing element  50 . 
     The plural sensing elements  50  are disposed so that the angle  207  formed by the line  50   e  connecting the centroid  53  of the sensing element  50  and centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer is within a difference of 5° between at least two sensing elements of the plural sensing elements  50  on the film part  64 . In the example illustrated in  FIGS. 10A and 10B , the number of the plural sensing elements  50  in which the difference of the angles  207  formed by the lines  50   e  connecting the centroids  53  of the sensing elements  50  and the centroid  68  of the film part  64 , and the magnetization  120   a  of the magnetization fixed layer is within 5° is not limited to two elements at the positions that are symmetrical with respect to the centroid of the film part  64 , and may be two or more elements at the positions that are not symmetrical with respect to the centroid of the film part  64 . For example, the number of the sensing elements  50  may be three or more disposed in a row in the circumferential direction of the film part  64 . 
     Here, when the pressure is applied to the film part  64 , it is considered that strain occurs in a direction parallel to the line  50   e  connecting the centroid  53  of the sensing element  50  and the centroid  68  of the film part  64 . 
     In a case where the sensing elements  50  have shape isotropy, the sensing elements  50  are disposed on the film surface  64  by a disposition method disclosed in any one of the disposition method described with reference to  FIGS. 7A and 7B  and the disposition method described with reference to  FIGS. 9A and 9B . 
     In a case where the sensing elements  50  have shape anisotropy, the sensing elements  50  are disposed on the film surface  64  by a disposition method disclosed in any one of the disposition method described with reference to  FIGS. 8A and 8B  and the disposition method described with reference to  FIGS. 10A and 10B . 
     As described later, in the disposition of the plural sensing elements  50  with respect to the film part  64  as illustrated in  FIGS. 7A to 10B , an angle formed by a magnetization  110   a  of a magnetization free layer and the magnetization  120   a  of the magnetization fixed layer may be within a difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film surface  64 . 
       FIGS. 11A to 11C  are schematic diagrams illustrating an operation of the pressure sensor according to the embodiment. 
       FIG. 11A  is a schematic cross-sectional view of the portion including the film part  64 .  FIGS. 11B and 11C  are schematic views illustrating signal processing of the pressure sensor  310 ,  FIG. 11B  is a schematic view illustrating a case where the plural sensing elements  50  are electrically connected in series.  FIG. 11C  is a schematic view illustrating a case where the plural sensing elements  50  are electrically connected in parallel. 
     First, as illustrated in  FIG. 11A , when an external pressure  80  is applied, the film part  64  is bent by the external pressure  80 . For example, the film part  64  is bent in an outwardly convex shape. If the film part  64  is bent in the outwardly convex shape, a stress  81  is applied to the sensing elements  50 , In the case of  FIG. 11A , tensile stress is applied to the sensing elements  50 . If the film part  64  is bent in a concave shape, compressive stress is applied to the sensing elements  50 . 
     If the stress  81  is applied to the sensing elements  50 , the electrical resistance of the sensing elements  50  is changed according to the stress  81  due to the inverse-magnetostriction effect and the MR effect described above. 
     As illustrated in  FIG. 11B , when the plural sensing elements  50  are connected in series, a signal  50   sg  of which a signal voltage is N times is transmitted to a processing circuit  113  as a signal variation, according to the number of elements N. Here, thermal noise and Schottky noise increase by a factor of √N with respect to the number N of elements. In other words, the signal-noise ratio (SNR) increases by the factor of √N using the sensing elements  50  of the number of elements N. By increasing the number N of the elements, it is possible to improve the SN ratio without increase in the size (diaphragm size) of the film part  64 . 
     By using the disposition of the plural sensing elements  50  with respect to the film part  64  as illustrated in  FIGS. 7A to 10B , it is possible to cause the direction of the strain applied to the sensing element  50  and the direction of the magnetization  120   a  of the second magnetic layer  20  to be the same in the plural sensing elements  50 . Further, it is possible to cause the angle formed by the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer to be the same in the plural sensing elements  50 . Thus, in the plural sensing elements  50  on the film part  64 , it is possible to obtain the change of the electrical resistance due to the same MR effect. Thus, it is possible to dispose many sensing elements  50  along the boundary  65  between the film part  64  and the fixing part  67 , as illustrated in  FIG. 7A . Thus, it is possible to simply add each signal  50   sg ′ thereto. By using the disposition of the plural sensing elements  50  with respect to the film part  64  as illustrated in  FIG. 7A to 10B , it is possible to cause the direction of the strain applied to the sensing element  50  and the direction of the magnetization  120   a  of the second magnetic layer  20  to be the same in the plural sensing elements  50 . Thus, it is not necessary to perform a special process for the signal  50   sg  from the plural sensing elements  50  that are electrically connected in series. Thus, it is possible to increase the number N of elements, and to achieve improvement of the sensitivity of the pressure sensor  310 . 
       FIGS. 12A to 14C  are schematic plan views illustrating change in magnetization with respect to stress. 
       FIGS. 12A to 14C  are schematic plan views illustrating change in magnetization of the magnetization free layer with respect to stress and change in magnetization of the magnetization fixed layer with respect to stress. 
       FIGS. 12A to 12C  are schematic plan views illustrating change in magnetization in a sensing element that does not have shape anisotropy.  FIGS. 13A to 14C  are schematic diagrams illustrating change in magnetization in a sensing element that has shape anisotropy. A method for manufacturing the sensing elements  50  as illustrated in  FIGS. 12A to 14C  will be described later. 
       FIGS. 12A ,  13 A and  14 A represent magnetization in the sensing element  50  in a case where the stress is not applied to the sensing element  50 .  FIGS. 12B ,  13 B and  14 B represent magnetization in the sensing element  50  in a case where the tensile stress  81  is applied to the sensing element  50 .  FIGS. 12C ,  13 C, and  14 C represent magnetization in the sensing element  50  in a case where the compressive stress  82  is applied to the sensing element  50 . 
     In a case where the stress is not applied thereto, the relationship between the magnetization  110   a  of the magnetization free layer (for example, the first magnetic layer  10 ) and the magnetization  120   a  of the magnetization fixed layer (for example, the second magnetic layer  20 ) may be parallel or non-parallel due to selection of the materials of the magnetization free layer and the magnetization fixed layer or setting of the direction of the magnetization of the magnetization free layer. In  FIGS. 12A and 13A , a case where the relationship between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer is non-parallel will be described as an example. 
     As illustrated in  FIG. 12B , when the tensile stress  81  is applied, a relative angle between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer becomes small compared with a relative angle in the case of  FIG. 12A . Thus, the electrical resistance is decreased due to the MR effect. 
     On the other hand, as illustrated in  FIG. 12C , when the compressive stress  82  is applied, a relative angle between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer is not changed from the relative angle in the case of  FIG. 12A . Thus, the change in the electrical resistance due to the MR effect does not occur. 
     As illustrated in  FIGS. 12A to 12C , the magnetization  120   a  of the magnetization fixed layer is perpendicular to one axis  50   a  of the sensing element  50 . This is within a difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film part  64 . That is, the magnetization  120   a  of each magnetization fixed layer of the plural sensing elements  50  on the film part  64  is within 5° in the direction that is perpendicular to one axis  50   a  of the sensing element  50 . In other words, the magnetization  120   a  of each magnetization fixed layer of the plural sensing elements  50  on the film part  64  is within 5° in the direction that is perpendicular to the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance. The angle formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance, and the magnetization  120   a  of the magnetization fixed layer is within the difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film part  64 . The magnetizations  120   a  of at least two magnetization fixed layers among the plural sensing elements  50  on the film part  64  have different directions. That is, the direction of the magnetization  120   a  of the magnetization fixed layer of any one sensing element (first sensing element) among the plural sensing elements  50  on the film part  64  is different from the direction of the magnetization  120   a  of the magnetization fixed layer of the sensing element (second sensing element) that is any one sensing element of the plural sensing elements  50  on the film part  64 , which is different from the first sensing element. 
     Accordingly, the angle formed by the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer is within the difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film part  64 . Thus, in the plural sensing elements  50  on the film part  64 , it is possible to obtain change in the electrical resistance due to the same MR effect. Thus, as illustrated in  FIG. 7A , it is possible to dispose many sensing elements  50  along the boundary  65  between the film part  64  and the fixing part  67 . Thus, it is possible to increase the number N of elements, and to achieve improvement of the sensitivity of the pressure sensor  310 . 
     When the sensing elements  50  have shape anisotropy, anisotropy also exists in the magnetization direction. In a case where the stress is not applied, the magnetization  110   a  of the magnetization free layer is directed along the long axis  50   b . In  FIGS. 13A to 13C , the magnetization  120   a  of the magnetization fixed layer is also fixed in the direction along the long axis  50   b.    
     As illustrated in  FIG. 13B , when the tensile stress  81  is applied, the relative angle formed by the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer changes from the relative angle of the case in  FIG. 13A . Thus, change in the electrical resistance due to the MR effect occurs. This is similarly applied even to a case where the compressive stress  82  is applied, as illustrated in  FIG. 13C . 
     As described above with reference to  FIGS. 8A and 8B , the plural sensing elements  50  are disposed so that the angle  206  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the long axis  50   b  is within the difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film part  64 . As described above, the magnetization  120   a  of the magnetization fixed layer is fixed in the direction along the long axis  50   b . Thus, the magnetizations  120   a  of at least two magnetization fixed layers among the plural sensing elements  50  on the film part  64  have different directions. 
     Accordingly, in the plural sensing elements  50  on the film part  64 , it is possible to achieve change in the electrical resistance due to the same MR effect. Thus, as illustrated in  FIG. 8A , it is possible to dispose many sensing elements  50  along the boundary  65  between the film part  64  and the fixing part  67 . Thus, it is possible to increase the number N of elements, and achieve improvement of the sensitivity of the pressure sensor  301 . 
     In the case of  FIGS. 14A to 14C , differently from the case of  FIGS. 13A to 13C , the magnetization  120   a  of the magnetization fixed layer is not directed along the long axis  50   b.    
     As illustrated in  FIG. 14B , when the tensile stress  81  is applied, compared with a case where the stress is not applied (case of  FIG. 14A ), the relative angle between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer is reduced. 
     On the other hand, as illustrated in  FIG. 14C , when the compressive stress  82  is applied, compared with a case where the stress is not applied (case of  FIG. 14A ), the relative angle between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer is increased. In the case of the sensing element  50  illustrated in  FIGS. 14A to 14C , as the stress changes from the compression stress to the tensile stress, the resistance of the sensing element  50  becomes small. 
     As described above with reference to  FIGS. 8A to 8B , the plural sensing elements  50  are disposed so that the angle  206  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the long axis  50   b  is within the difference of 5° between at least two sensing elements among the plural sensing elements  50  on the film part  64 , Thus, the magnetizations  120   a  of at least two magnetization fixed layers among the plural sensing elements  50  on the film part  64  have different directions. 
     Accordingly, in the plural sensing elements  50  on the film part  64 , it is possible to achieve change in the electrical resistance due to the same MR effect. Thus, as illustrated in  FIG. 8A , it is possible to dispose many sensing elements  50  along the boundary  65  between the film part  64  and the fixing part  67 . Thus, it is possible to increase the number N of elements, and achieve improvement of the sensitivity of the pressure sensor  301 . 
     Second Embodiment 
     Next, a method for manufacturing the pressure sensor  310  will be described. 
       FIG. 15  is a flowchart illustrating a method for manufacturing a pressure sensor according to a second embodiment. 
       FIGS. 16A to 16E  are schematic process diagrams illustrating the method for manufacturing the pressure sensor. 
     In  FIGS. 16A to 16E , for ease of understanding, shapes and sizes of respective elements are appropriately modified from those illustrated in  FIG. 1 . Further, the shape of the film part  64  employs the circle as illustrated in  FIG. 2A . 
       FIG. 16D  illustrates a method for manufacturing the hollow part  70  to be formed from a rear surface of a substrate. In a case where the method is used, a system-in-package (SiP) configuration in which a circuit unit is formed as a separate chip and a pressure sensor and the circuit unit are formed as one package in a mounting process is used. 
       FIG. 16E  illustrates a method for manufacturing the hollow part  70  to be formed from an upper portion of the substrate. In a case where the method is used, a system-on-chip (SoC) configuration in which a CMOS circuit or the like is provided in a lower portion of the substrate is used. 
     As illustrated in  FIGS. 15 and 16A , a film  64   fm  that is used to form the film part  64  is formed (step S 101 ). The film  64   fm  that is used to form the film part  64  is formed on the base unit  71 , The base unit  71  includes, for example, a silicon substrate. The film  64   fm  includes, for example, a silicon oxide film. In a case where the fixing part  67  that fixes the film part  64  to the base unit  71  is formed, the fixing part  67  may be formed by patterning the film  64   fm  in this process. As the shape of the film surfaces  64   a  and  64   b , the circle in  FIG. 2A  is employed in  FIGS. 16A to 16E . 
     As illustrated in  FIGS. 15 and 16B , the first interconnect  57  is formed (step S 103 ). For example, as illustrated in  FIG. 16B , a conductive film is formed on the film  64   fm  (or the film part  64 ), and is then patterned in a predetermined shape to form the first interconnect  57 . 
     In  FIG. 16B , for ease of understanding, a part of the plural first interconnects  57  are illustrated. 
     As illustrated in  FIGS. 15 and 16C , the sensing element  50  is formed (step S 105 ). For example, as illustrated in  FIG. 16C , the sensing element  50  is formed on a pad  57   a  (see  FIG. 16A ) of the first interconnect  57 . Films that serve as components that form the sensing element  50  are sequentially formed to form a stacked film. Further, the stacked film is patterned in a predetermined shape to form the sensing element  50 . 
     As illustrated in  FIGS. 15 and 16D , the second interconnect  58  is formed (step S 107 ). For example, as illustrated in  FIGS. 16D and 16E , an insulating film (not shown) is formed to cover the sensing element  50 , and a part of the insulating film is removed to expose an upper surface of the sensing element  50 . A conductive layer is formed thereon, and is then patterned in a predetermined shape to form the second interconnect  58 . 
     At least a part of steps S 101  to S 107  may be simultaneously performed in a technically allowable range, or may be switched in order. 
     Then, as illustrated in  FIGS. 15 and 16E , the hollow part  70 , the film part  64  and the fixing part  67  are formed (step S 109 ). For example, as illustrated in  FIGS. 15D and 16E , an etching process is performed from the rear surface (lower surface) side of the base unit  71  to form the hollow part  70 . A portion where the hollow part  70  is not formed becomes a non-hollow part, and the film part  64  and the fixing part  67  are formed therein. 
     The etching process may be performed using a deep reactive ion etching (RIE) process, a Bosch process or the like, for example. 
     Then, in order to create the sensing element  50  illustrated in  FIGS. 12A to 14C , fixing of the magnetization  120   a  of the magnetization fixed layer due to annealing is performed (step S 111 ). 
     Hereinafter, the method will be described. 
       FIGS. 17A to 17D  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 12A to 12C . 
       FIGS. 17A to 17D  are schematic process diagrams of the process of step S 105  illustrated in  FIG. 15 . 
     As the shape of the film surfaces  64   a  and  64   b , the circle in  FIG. 2A  is employed. 
       FIG. 17A  is a schematic plan view illustrating the shape of a mask  51  on a stacked film  50   c  obtained by sequentially forming the films that serve as the components that form the sensing elements  50 . 
     The square mask  51  having no shape anisotropy is formed around the boundary  65  between the film part  64  and the fixing part  67  after the sensing element  50  is formed. Thus, the sensing elements  50  having no shape anisotropy are formed around the boundary  65  through the etching process. 
       FIG. 17B  is a schematic cross-sectional view illustrating the pressure sensor  310  while the magnetization fixing is performed due to annealing. 
     As in an external pressure  85  in  FIG. 17B , by applying the external pressure  85  to the film surfaces  64   a  and  64   b  of the diaphragm from the side of the hollow part  70  of the diaphragm or the opposite side, a static strain is caused on the film surfaces  64   a  and  64   b . As illustrated in  FIG. 17B , in a case where the external pressure  85  is applied from the side of the hollow part  70  of the diaphragm, a compressive stress  86  occurs in the sensing element  50  formed around the boundary  65  between the film part  64  and the fixing part  67 . 
       FIG. 17C  is a schematic plan view illustrating the magnetization  110   a  of the magnetization free layer of the sensing element  50  during annealing and the magnetization  120   a  of the magnetization fixed layer of the sensing element during annealing. 
     During annealing, the static strain occurs in the diaphragm as described above, Thus, both of the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer before the magnetization fixing are changed due to the inverse-magnetostriction effect. Whether the magnetization is directed in a direction parallel with or in a direction perpendicular to the direction of the stress  86  is selectable according to selection of the material of the magnetic layer. In  FIG. 17C , a case where the magnetization is directed in the direction perpendicular to the compressive stress  86  is employed. 
       FIG. 17D  is a schematic plan view illustrating the magnetization  110   a  of the magnetization free layer after the stress  86  is removed and the magnetization  120   a  of the magnetization fixed layer after the stress  86  is removed, after the magnetization fixing. 
     The magnetization  120   a  of the magnetization fixed layer is fixed in a direction based on the inverse-magnetostriction effect during annealing. On the other hand, the inverse-magnetostriction effect disappears as the stress  86  is removed, and the magnetization  110   a  of the magnetization free layer is directed in an antiparallel direction with respect to the magnetization  120   a  of the magnetization fixed layer. In a case where the stress is not applied, the relationship between the magnetization  110   a  and the magnetization  120   a  of the magnetization fixed layer may be selectively parallel or antiparallel according to selection of the materials or application of an external magnetic field after annealing. Similar to  FIGS. 12A and 13A , the antiparallel is employed in  FIGS. 17D and 18B . 
       FIGS. 18A and 18B  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 13A to 13C . 
       FIGS. 18A and 18B  are schematic process diagrams of the process in step S 105  illustrated in  FIG. 15 . 
     As the shape of the film surfaces  64   a  and  64   b , the circle in  FIG. 2A  is employed. 
       FIG. 18A  is a plan view illustrating the shape of a mask  52  on the stacked film  50   c  obtained by sequentially forming the films that serve as the components that form the sensing elements  50 . 
     The rectangular mask  52  having shape anisotropy is formed around the boundary  65  between the film part  64  and the fixing part  67 . Here, the mask  52  is formed so that the angle  206  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the long axis  50   b  is within a difference of 5° between at least two masks among the plural masks  52  on the film part  64 . After forming the masks  52 , the sensing elements  50  having shape anisotropy are formed around the boundary  65  by the etching process. 
       FIG. 18B  is a schematic plan view illustrating the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer in a case where the sensing element  50  is formed by the method illustrated in  FIG. 18A . 
     As described above, in a case where the sensing element  50  has shape anisotropy, the magnetization of the magnetic layer is directed in the direction along the long axis  50   b  of the sensing element  50 . Thus, the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer are directed in an antiparallel direction along the long axis  50   b.    
     Here, the directions of the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer are not determined in the forming stage of the sensing element  50 . Thus, the magnetization of each magnetic layer may be opposite to the case of  FIG. 18B . 
     By performing the annealing and the magnetization fixing for the sensing element  50  in the state of  FIG. 18B , it is possible to form the sensing element  50  illustrated in  FIGS. 13A to 13C . 
     In a case where the stress is not applied after annealing, the relationship between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer may be selectively parallel or antiparallel according to selection of the materials or application of an external magnetic field after annealing. 
       FIGS. 19A to 19D  are schematic process diagrams illustrating the method for manufacturing the sensing element illustrated in  FIGS. 14A to 14C . 
       FIGS. 19A to 19D  are schematic process diagrams of the process in step S 105  illustrated in  FIG. 15 . 
     As the shape of the film surfaces  64   a  and  64   b , the circle in  FIG. 2A  is employed. 
       FIG. 19A  is a schematic plan view illustrating the shape of a mask  52  on the stacked film  50   c  obtained by sequentially forming the films that serve as the components that form the sensing elements  50 . 
     The rectangular mask  52  having shape anisotropy is formed around the boundary  65  between the film part  64  and the fixing part  67 . Here, the mask  52  is formed so that the angle  206  formed by the line  50   d  connecting the centroid  53  of the sensing element  50  and the boundary  65  in the shortest distance and the long axis  50   b  is within a difference of 5° between at least two masks among the plural masks  52  on the film part  64 . After forming the masks  52 , the sensing elements  50  having shape anisotropy are formed around the boundary  65  by the etching process. 
       FIG. 19B  is a schematic cross-sectional view illustrating the pressure sensor  310  while the magnetization fixing is performed due to annealing. 
     As in an external pressure  85  in  FIG. 19B , by applying the external pressure  85  to the film surfaces  64   a  and  64   b  of the diaphragm from the side of the hollow part  70  of the diaphragm or the opposite side, a static strain is caused on the film surfaces  64   a  and  64   b . As illustrated in  FIG. 19B , in a case where the external pressure  85  is applied from the side of the hollow part  70  of the diaphragm, a compressive stress  86  occurs in the sensing element  50  formed around the boundary  65  between the film part  64  and the fixing part  67 . 
       FIG. 19C  is a schematic plan view illustrating the magnetization  110   a  of the magnetization free layer of the sensing element  50  during annealing and the magnetization  120   a  of the magnetization fixed layer of the sensing element  50  during annealing. 
     During annealing, the static strain occurs in the diaphragm as described above. Thus, both of the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer before the magnetization fixing are changed due to the inverse-magnetostriction effect. Whether the magnetization is directed in a direction parallel with or in a direction perpendicular to the direction of the stress  86  is selectable according to selection of the material of the magnetic layer or application of an external magnetic field after annealing. In  FIG. 19C , a case where the magnetization is directed in the direction perpendicular to the compressive stress  86  is employed. 
       FIG. 19D  is a schematic plan view illustrating the magnetization  110   a  of the magnetization free layer after the stress  86  is removed and the magnetization  120   a  after the stress  86  is removed, after the magnetization fixing. 
     The magnetization  120   a  of the magnetization fixed layer is fixed in a direction based on the inverse-magnetostriction effect during annealing. On the other hand, the inverse-magnetostriction effect disappears as the stress  86  is removed, and the magnetization  110   a  of the magnetization free layer is directed in the direction along the long axis  50   b  of the sensing element  50  due to magnetic anisotropy. 
       FIG. 20  is a graph illustrating the relationship between the stress applied to the sensing element illustrated in  FIGS. 14A to 14C  and the electrical resistance. 
       FIG. 20  is a graph illustrating change in the electrical resistance in a case where each of the compressive stress and the tensile stress is applied to the sensing element  50  formed by the process described above with reference to  FIGS. 19A to 19D . 
     Whether the electrical resistance becomes low when the magnetization  110   a  of the magnetic free layer and the magnetization  120   a  of the magnetization fixed layer are parallel with each other or when the magnetization  110   a  of the magnetic free layer and the magnetization  120   a  of the magnetization fixed layer are antiparallel with each other is selectable according to selection of the materials of the first magnetic layer  10 , the second magnetic layer  20  and the intermediate layer  30  of the sensing element  50 . In  FIG. 20 , a case where the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer are antiparallel with each other and the electrical resistance becomes high is employed. 
     As illustrated in  FIG. 14B , in a case where the tensile stress  81  is applied to the sensing element  50 , a relative angle  200   b  between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer becomes small compared with a relative angle  200   c  in a case where the stress  81  is not applied, and the electrical resistance becomes low due to the MR effect. 
     On the other hand, as illustrated in  FIG. 14C , in a case where the compressive stress  82  is applied to the sensing element  50 , the relative angle  200   b  between the magnetization  110   a  of the magnetization free layer and the magnetization  120   a  of the magnetization fixed layer becomes zero and becomes large compared with the relative angle  200   c  in a case where the stress  82  is not applied, and thus, the electrical resistance becomes high due to the MR effect. 
     As described above, in the sensing element  50  formed by the process described above with reference to  FIGS. 19A to 19D  as illustrated in  FIG. 20 , the value of the electrical resistance becomes high as the direction of the applied stress changes from the compressive stress to the tensile stress. 
     Third Embodiment 
     As illustrated in  FIGS. 17B and 19B , an apparatus for performing annealing in a state where the stress is applied to the diaphragm will be described. 
       FIG. 21  is a schematic cross-sectional view illustrating a manufacturing apparatus of a pressure sensor according to a third embodiment. 
       FIG. 21  is a schematic cross-sectional view illustrating an apparatus for performing external pressure control based on decompression suction with respect to the pressure sensor. 
     A manufacturing apparatus  400  of the pressure sensor illustrated in  FIG. 21  includes a first jig  410 , a second jig  420 , a third jig  430 , a cylindrical tube  460 , and a vacuum pump (pressure difference generator)  470 . 
     As illustrated in  FIG. 21 , a substrate  401  for which the processes up to step S 105  in  FIG. 15  are performed and on which the pressure sensor  310  is formed is fixed by the first jig  410 . Further, the second jig  420  is mounted on the first jig  410  to form a space  440  (a first space). The third jig  430  is mounted under the first jig  410  to form a space  450  (a second space). 
     The cylindrical tube  460  for mounting the vacuum pump  470  is provided to the third jig  430 . After the vacuum pump  470  is operated to suction gas (for example, air) in the space  450 , a connection part  460   a  of the cylindrical tube  460  and the vacuum pump  470  is sealed, and thus, a difference between degrees of vacuum is caused between the space  440  and the space  450  to generate the external pressure  85 . 
       FIG. 22  is a schematic cross-sectional view illustrating another manufacturing apparatus of the pressure sensor according to the third embodiment. 
       FIG. 22  is a schematic cross-sectional view illustrating an apparatus for performing external pressure control based on pressure discharge with respect to the pressure sensor. 
     A manufacturing apparatus  400   a  of the pressure sensor in  FIG. 22  includes the first jig  410 , the second jig  420 , the third jig  430 , the cylindrical tube  460 , and a container  480  such as a cylinder, for example. As illustrated in  FIG. 22 , a substrate  401  for which the processes up to step S 105  in  FIG. 15  are performed and on which the pressure sensor  310  is formed is fixed by the first jig  410 . Further; the second jig  420  is mounted on the first jig  410  to form a space  440  (a first space). The third jig  430  is mounted under the first jig  410  to form a space  450  (a second space). 
     The cylindrical tube  460  for mounting the container  480  is provided to the third jig  430 . After the container  480  (pressure difference generator; for example, high pressure cylinder) is operated to discharge gas (for example, air) in the space  450 , a connection part  460   a  of the cylindrical tube  460  and the container  480  is sealed, and thus, a pressure difference is caused between the space  440  and the space  450  to generate the external pressure  85 . An inert gas such as Ar, Xe, Kr or N 2  may be inserted into the space  450  to form a positive pressure, and then, the connection part  460   a  between the cylindrical tube  460  and the container  480  may be sealed. 
     In the manufacturing apparatus  400  in  FIG. 21  and the manufacturing apparatus  400   a  in  FIG. 22 , in order to prevent breakage of the film part  64 , the size of the external pressure  85  is set to 30 KPa (kilopascals) or less. 
     By inserting the manufacturing apparatus  400  in which the connection part  460   a  is sealed into an annealing apparatus to perform annealing, it is possible to perform the annealing in a state where a static strain is caused on the film surfaces  64   a  and  64   b  of the pressure sensor  310 . Here, a heater may be directly provided to the manufacturing apparatus  400  to form an annealing apparatus. 
     In the above-described manufacturing apparatuses in  FIGS. 21 and 22 , an example in which the sealing is performed in a state where the space  450  is decompressed or pressurized is described, but as long as the pressure difference between the space  440  and the space  450  can be controlled, heat treatment may be performed in a state where the suction due to the pump or the discharge due to the container  480  are continuously performed. 
     It is favorable that the annealing temperature be equal to or higher than the blocking temperature of the antiferromagnetic material used in the pinning layer  160 . Further, in a case where an antiferromagnetic layer including Mn is used, it is favorable that the annealing temperature be equal to or lower than a temperature at which the diffusion of Mn occurs. For example, the annealing temperature may be set to 200° C. or higher and 500° C. or lower. In such a case, favorably, the annealing temperature may be set to 250° C. or higher and 400° C. or lower. 
     In order to fix magnetization of the ferromagnetic layer being in contact with the pinning layer  160 , the heat treatment is performed while the magnetic field is applied. The magnetization of the ferromagnetic layer being in contact with the pinning layer  160  is fixed in the direction of the magnetic field applied in the heat treatment. The annealing temperature is set to be equal to or higher than the blocking temperature of the antiferromagnetic material used in the pinning layer, for example. Further, when an antiferromagnetic layer including Mn is used, it is favorable that the annealing temperature be equal to or lower than a temperature at which the diffusion of Mn occurs. For example, the annealing temperature may be set to 200° C. or higher and 500° C. or lower. Favorably, the annealing temperature may be set to 250° C. or higher and 400° C. or lower. 
     Fourth Embodiment 
       FIG. 23  is a schematic plan view illustrating a microphone according to a fourth embodiment. 
     As illustrated in  FIG. 23 , a microphone  510  includes any pressure sensor  310  according to the respective embodiments described above or a pressure sensor according to a modification of these pressure sensors. Hereinafter, the microphone  510  that includes the pressure sensor  310  will be described as an example. 
     The microphone  510  is embedded in an end portion of a personal digital assistant  520 . The film part  64  of the pressure sensor  310  provided in the microphone  510  may be substantially parallel to, for example, a surface of the personal digital assistant  520  where a display unit  521  is provided. The disposition of the film part  64  is not limited to the above illustration and may be appropriately modified. 
     Since the microphone  510  includes the pressure sensor  310  or the like, it is possible to achieve high sensitivity with respect to frequencies in a wide band. 
     Further, a case where the microphone  510  is embedded in the personal digital assistant  520  is illustrated, this is not limitative. The microphone  510  may also be embedded in, for example, an IC recorder, a pin microphone, or the like. 
     Fifth Embodiment 
     The embodiment relates to an acoustic microphone using the pressure sensor of the embodiments described above. 
       FIG. 24  is a schematic cross-sectional view illustrating the acoustic microphone according to a fifth embodiment. 
     According to the embodiment, an acoustic microphone  530  includes a printed circuit board  531 , a cover  533 , and the pressure sensor  310 . The printed circuit board  531  includes, for example, a circuit such as an amplifier. An acoustic hole  535  is provided in the cover  533 . Sound  539  passes through the acoustic hole  535  to enter the inside of the cover  533 . 
     Any of the pressure sensors described in regard to the embodiments described above or a pressure sensor according to a modification of these pressure sensors may be used as the pressure sensor  310 . 
     The acoustic microphone  530  responds to sound pressure. The acoustic microphone  530  of high sensitivity is obtained by using the pressure sensor  310  of high sensitivity. For example, the pressure sensor  310  is mounted on the printed circuit board  531 , and then, electrical signal lines are provided. The cover  533  is provided on the printed circuit board  531  to cover the pressure sensor  310 . 
     According to the embodiment, it is possible to provide an acoustic microphone of high sensitivity. 
     Sixth Embodiment 
     The embodiment relates to a blood pressure sensor using the pressure sensor of the embodiments described above. 
       FIGS. 25A and 25B  are schematic views illustrating the blood pressure sensor according to a sixth embodiment. 
       FIG. 25A  is a schematic plan view illustrating the skin on the arterial vessel of a human.  FIG. 25B  is a cross-sectional view along line H 1 -H 2  of  FIG. 25A . 
     In the embodiment, the pressure sensor  310  is used as a blood pressure sensor  540 . The pressure sensor  310  includes any of the pressure sensors described in regard to the embodiments described above or a pressure sensor according to a modification of these pressure sensors. 
     Thus, it is possible to perform highly-sensitive pressure sensing by a small pressure sensor. The blood pressure sensor  540  can perform a continuous blood pressure measurement by the pressure sensor  310  being pressed onto a skin  543  on an arterial vessel  541 . 
     According to the embodiment, it is possible to provide a blood pressure sensor of high sensitivity. 
     Seventh Embodiment 
     The embodiment relates to a touch panel using the pressure sensor of the embodiments described above. 
       FIG. 26  is a schematic plan view illustrating a touch panel according to a seventh embodiment. 
     In the embodiment, the pressure sensor  310  may be used in a touch panel  550 . The pressure sensor  310  includes any of the pressure sensors described in regard to the embodiments described above or a pressure sensor according to a modification of these pressure sensors. In the touch panel  550 , the pressure sensor  310  is provided in the interior of the display and/or outside the display. 
     For example, the touch panel  550  includes plural first interconnects  551 , plural second interconnects  552 , the plural pressure sensors  310 , and a controller  553 . 
     In the example, the plural first interconnects  551  are arranged along the Y-axis direction. Each of the plural first interconnects  551  extends along the X-axis direction. The plural second interconnects  552  are arranged along the X-axis direction. Each of the plural second interconnects  552  extends along the Y-axis direction. 
     The plural pressure sensors  310  are provided respectively at intersection portions between the plural first interconnects  551  and the plural second interconnects  552 . One pressure sensor  310  is used as one sensing component  310   e  for sensing. Herein, the intersection portions include positions where the first interconnects  551  and the second interconnects  552  intersect with each other and peripheral regions thereof. 
     One end  310   a  of each of the plural pressure sensors  310  is connected to each of the plural first interconnects  551 , The other end  310   b  of each of the plural pressure sensors  310  is connected to each of the plural second interconnects  552 . 
     The controller  553  is connected to the plural first interconnects  551  and the plural second interconnects  552 . 
     For example, the controller  553  includes a first interconnect circuit  553   a  that is connected to the plural first interconnects  551 , a second interconnect circuit  553   b  that is connected to the plural second interconnects  552 , and a control circuit  555  that is connected to the first interconnect circuit  553   a  and the second interconnect circuit  553   b.    
     The pressure sensor  310  can perform highly-sensitive pressure sensing with a small size. Thus, it is possible to realize a high definition touch panel. 
     Other than the applications described above, the pressure sensors according to the embodiments described above are applicable to various pressure sensor devices such as an atmospheric pressure sensor, an air pressure sensor of a tire. 
     According to the embodiments, it is possible to provide a pressure sensor of high sensitivity, a microphone, a blood pressure sensor and a touch panel, a pressure sensor manufacturing method, and a pressure sensor manufacturing apparatus. 
     Hereinabove, the embodiments of the invention are described with reference to the specific examples. However, the invention is not limited to the specific examples. For example, specific configurations of the respective components such as the film part, the sensing element, the first magnetic layer, the second magnetic layer and the intermediate layer included in the pressure sensor, the microphone, the blood pressure sensor and the touch panel are included in the scope of the invention as long as the specific configurations can be appropriately selected by those skilled in the art from known techniques to realize the invention in the same way and to achieve the same results. 
     Further, combinations of two or more components of the respective specific examples in a technically allowable range are also included in the scope of the invention in a range without departing from the spirit of the invention. 
     In addition, all pressure sensors, microphones, blood pressure sensors and touch panels obtainable by an appropriate design modification by those skilled in the art based on the pressure sensors, the microphones, the blood pressure sensors and the touch panels described above as the embodiments of the invention also are included in the scope of the invention in a range without departing from the spirit of the invention. 
     Various other variations and modifications can be conceived by those skilled in the art within the spirit of the invention, and it is understood that such variations and modifications are also encompassed within the scope of the invention. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. 
     Hereinabove, the embodiments of the invention are described. The embodiments of the invention may be embodied in the following embodiments. 
     Embodiment 1 
     A microphone comprising a pressure sensor, 
     the pressure sensor including: 
     a support unit; 
     a substrate supported by the support unit, the substrate being deformable; and 
     a plurality of sensing elements provided on a part of the substrate, 
     the sensing element including
         a first magnetic layer in which magnetization changes according to deformation of the substrate,   a second magnetic layer in which magnetization is fixed, and   an intermediate layer provided between the first magnetic layer and the second magnetic layer, and       

     a direction of the magnetization of the second magnetic layer of a first sensing element among the plurality of sensing elements being different from a direction of the magnetization of the second magnetic layer of a second sensing element among the plurality of sensing elements. 
     Embodiment 2 
     A blood pressure sensor comprising a pressure sensor, 
     the pressure sensor including: 
     a support unit; 
     a substrate supported by the support unit, the substrate being deformable; and 
     a plurality of sensing elements provided on a part of the substrate, 
     the sensing element including
         a first magnetic layer in which magnetization changes according to deformation of the substrate,   a second magnetic layer in which magnetization is fixed, and   an intermediate layer provided between the first magnetic layer and the second magnetic layer, and       

     a direction of the magnetization of the second magnetic layer of a first sensing element among the plurality of sensing elements being different from a direction of the magnetization of the second magnetic layer of a second sensing element among the plurality of sensing elements. 
     Embodiment 3 
     A touch panel comprising a pressure sensor, 
     the pressure sensor including: 
     a support unit; 
     a substrate supported by the support unit, the substrate being deformable; and 
     a plurality of sensing elements provided on a part of the substrate, 
     the sensing element including
         a first magnetic layer in which magnetization changes according to deformation of the substrate,   a second magnetic layer in which magnetization is fixed, and   an intermediate layer provided between the first magnetic layer and the second magnetic layer, and       

     a direction of the magnetization of the second magnetic layer of a first sensing element among the plurality of sensing elements being different from a direction of the magnetization of the second magnetic layer of a second sensing element among the plurality of sensing elements. 
     Embodiment 4 
     An apparatus for manufacturing a pressure sensor, comprising: 
     a first jig configured to fix a substrate on which a plurality of sensing elements is provided, the substrate being deformable, in which each sensing element includes a first magnetic layer in which magnetization changes according to deformation of the substrate, a second magnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer; 
     a second jig provided above the first jig and configured to form a first space between the substrate and the second jig; 
     a third jig provided under the first jig and configured to form a second space between the substrate and the third jig; and 
     a pressure difference generator configured to generate a pressure difference between the first space and the second space and deform the substrate due to an external pressure based on the pressure difference.