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JP2015137869

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DESCRIPTION JP2015137869
Embodiments of the present invention provide a highly sensitive pressure sensor, a microphone,
an acceleration sensor, and a method of manufacturing a pressure sensor. According to one
embodiment, a pressure sensor is provided that includes a substrate and a sensor portion. The
sensor unit has a first surface, a flexible transducing thin film, a first strain sensing element
provided on the first surface, and a first strain sensing element provided on the first surface and
separated from the first strain sensing element. And b. The first strain sensing element is
provided between a first magnetic layer having a variable direction of magnetization, a first film
containing oxygen at a first concentration, and the first magnetic layer and the first film, and the
direction of magnetization is fixed. And a first intermediate layer provided between the first
magnetic layer and the second magnetic layer. The second strain sensing element is provided
between the third magnetic layer in which the direction of magnetization is variable, the second
film whose oxygen concentration is different from the first concentration, and the third magnetic
layer and the second film, and the direction of magnetization And a second intermediate layer
provided between the third magnetic layer and the fourth magnetic layer. [Selected figure] Figure
1
Pressure sensor, microphone, acceleration sensor and method of manufacturing pressure sensor
[0001]
Embodiments of the present invention relate to a pressure sensor, a microphone, an acceleration
sensor, and a method of manufacturing the pressure sensor.
[0002]
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For example, there is a pressure sensor in which a plurality of strain sensors are provided on a
diaphragm.
In a pressure sensor, high sensitivity is desired.
[0003]
JP 2012-204479 A
[0004]
Embodiments of the present invention provide a method of manufacturing a highly sensitive
pressure sensor, a microphone, an acceleration sensor and a pressure sensor.
[0005]
According to an embodiment of the present invention, a pressure sensor is provided that includes
a substrate and a sensor unit.
The sensor unit includes a transducing thin film, a first strain sensing element, and a second
strain sensing element.
The transducing thin film has a first surface and is flexible. The first strain sensing element is
provided on the first surface. The second strain sensing element is provided on the first surface
and separated from the first strain sensing element. The first strain sensing element includes a
first magnetic layer having a variable magnetization direction, a first film containing oxygen at a
first concentration, a second magnetic layer having a fixed magnetization direction, and a first
intermediate layer. ,including. The second magnetic layer is provided between the first magnetic
layer and the first film. The first intermediate layer is provided between the first magnetic layer
and the second magnetic layer. The second strain sensing element includes a third magnetic
layer whose direction of magnetization is variable, a second film whose oxygen concentration is
different from the first concentration, a fourth magnetic layer whose direction of magnetization is
fixed, and a second magnetic layer. And an intermediate layer. The fourth magnetic layer is
provided between the third magnetic layer and the second film. The second intermediate layer is
provided between the third magnetic layer and the fourth magnetic layer.
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[0006]
It is a typical perspective view showing a pressure sensor concerning a 1st embodiment. It is a
schematic plan view showing a part of pressure sensor concerning a 1st embodiment. FIG. 3A to
FIG. 3D are schematic plan views showing the configuration of a part of the pressure sensor
according to the first embodiment. It is a typical perspective view showing a part of pressure
sensor concerning a 1st embodiment. FIG. 5A to FIG. 5C are schematic perspective views showing
the operation of the pressure sensor according to the first embodiment. FIG. 6A to FIG. 6C are
schematic perspective views showing a part of the pressure sensor according to the first
embodiment. FIGS. 7A to 7C are schematic perspective views showing a part of the pressure
sensor according to the first embodiment. FIGS. 8A and 8B are schematic views showing the
operation of the pressure sensor according to the first embodiment. FIG. 9A and FIG. 9B are
schematic views showing the operation of the pressure sensor according to the first embodiment.
It is a schematic diagram which shows the pressure sensor of a reference example. It is a
schematic diagram which shows another pressure sensor which concerns on 1st Embodiment. It
is a schematic diagram which shows another pressure sensor which concerns on 1st
Embodiment. It is a schematic diagram which shows another pressure sensor which concerns on
1st Embodiment. It is a schematic diagram which shows another pressure sensor which concerns
on 1st Embodiment. It is a schematic diagram which shows another pressure sensor which
concerns on 1st Embodiment. It is a schematic diagram which shows the manufacturing method
of the pressure sensor which concerns on 2nd Embodiment. It is a schematic diagram which
shows the manufacturing method of the pressure sensor which concerns on 2nd Embodiment. It
is a schematic diagram which shows the microphone which concerns on 3rd Embodiment. It is a
typical perspective view showing an acceleration sensor concerning a 4th embodiment. It is a
schematic plan view which shows the acceleration sensor which concerns on 4th Embodiment.
[0007]
Hereinafter, each embodiment will be described with reference to the drawings. The drawings are
schematic or conceptual, and the relationship between the thickness and width of each part, the
ratio of sizes between parts, and the like are not necessarily the same as the actual ones. In
addition, even in the case of representing the same portion, the dimensions and ratios may be
different from one another depending on the drawings. In the specification of the present
application and the drawings, the same elements as those described above with reference to the
drawings are denoted by the same reference numerals, and the detailed description will be
appropriately omitted.
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[0008]
First Embodiment FIG. 1 is a schematic perspective view illustrating a pressure sensor according
to a first embodiment. In FIG. 1, in order to make a figure legible, an insulation part is omitted
and a conductive part is mainly drawn. FIG. 2 is a schematic plan view illustrating a part of the
pressure sensor according to the first embodiment.
[0009]
As shown in FIG. 1, the pressure sensor 310 according to the present embodiment includes a
base 71 a and a sensor unit 72. The sensor unit 72 is provided on the base 71 a. The sensor unit
72 includes a transducing thin film 64, a fixing unit 67, a first strain sensing element 50A, and a
second strain sensing element 50B. The transducing thin film 64 has a film surface 64a (first
surface). The transducing film 64 is flexible. The transducing thin film 64 has a function of
bending when a pressure is applied from the outside and transducing the strain sensing element
50 formed thereon as a strain. The external pressure may be a pressure itself or a pressure by
sound waves or ultrasonic waves. In the case of sound or ultrasound, the pressure sensor will
function as a microphone.
[0010]
In some cases, the thin film to be the transducing thin film 64 is continuously formed outside the
portion bent by the external pressure. In the present specification, a portion which is surrounded
by the fixed end, is thinner than the fixed end with a certain thickness, and is flexed by the
external pressure, is called a transducing thin film.
[0011]
The fixing portion 67 is connected to the edge 64eg of the transducing thin film 64. The fixing
portion 67 fixes the edge 64eg to the base 71a. The first strain sensing element 50A and the
second strain sensing element 50B are provided on the film surface 64a. The configurations of
the first strain sensing element 50A and the second strain sensing element 50B will be described
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later.
[0012]
A cavity 70 is formed in the base 71a. The portion other than the hollow portion 70 in the base
71 a corresponds to the non-hollow portion 71. The non-cavity 71 is juxtaposed with the cavity
70.
[0013]
The hollow portion 70 is a portion where the material forming the non-hollow portion 71 is not
provided. The inside of the cavity 70 may be a vacuum (a low pressure state lower than 1 atm),
and the cavity 70 may be filled with a gas such as air or an inert gas. Further, the hollow portion
70 may be filled with a liquid. In the cavity 70, a deformable material may be disposed to allow
the transducing thin film 64 to bend.
[0014]
When a pressure (including sound and ultrasonic waves) is applied to the transducing thin film
64 from the outside, the transducing thin film 64 is bent. Along with this, distortion occurs in the
strain sensor (sensor unit 72) disposed on the transducing thin film 64. Thus, the transducing
thin film 64 transmits (transduces) a pressure signal to the sensor unit 72, and the pressure
signal is converted to a distortion signal in the sensor unit 72.
[0015]
The transducing thin film 64 is disposed above the cavity 70, and the fixing thin film 67 is fixed
to the base 71 a by the fixing portion 67.
[0016]
Here, a plane parallel to the film surface 64a is taken as an XY plane.
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If the film surface 64a can not be planar, the plane including the edge 64eg of the film surface
64a is taken as an XY plane. The direction perpendicular to the X-Y plane is taken as the Z-axis
direction.
[0017]
As shown in FIGS. 1 and 2, in the pressure sensor 310, the base 71a, the transducing thin film
64, the fixing portion 67 (the fixing portions 67a to 67d), the first strain sensing element 50A,
the second strain sensing element 50B, and A first wire 57 and a second wire 58 are provided. In
this example, a plurality of strain sensing elements 50 (strain sensing elements 50a to 50d) are
provided. The first strain sensing element 50A and the second strain sensing element 50B are
any of the plurality of strain sensing elements 50. For example, the strain sensing element 50a is
used as the first strain sensing element 50A. For example, the strain sensing element 50b is used
as the second strain sensing element 50B. Further, each of the plurality of strain sensing
elements 50 is disposed at a position different from the position of the center of gravity 64 b of
the film surface 64 a of the transducing thin film 64. For example, each of the plurality of strain
sensing elements 50 is disposed on a circumference centered on the center of gravity 64 b. For
example, each of the plurality of strain sensing elements 50 is disposed at a position equidistant
from the position of the center of gravity 64 b. That is, in this example, the distance between the
center of gravity 64b and the first strain sensing element 50A is substantially the same as the
distance between the center of gravity 64b and the second strain sensing element 50B. For
example, the distance between the center of gravity 64b and the first strain sensing element 50A
is not less than 0.8 times and not more than 1.2 times the distance between the center of gravity
64b and the second strain sensing element 50B. However, in the embodiment, the arrangement
of each of the plurality of strain sensing elements 50 can be changed as appropriate.
[0018]
In this example, a straight line passing through the first strain sensing element 50A and the
center of gravity 64b of the film surface 64a is along the Y-axis direction. In this example, a
straight line passing through the second strain sensing element 50B and the center of gravity
64b is along the X-axis direction. That is, in this example, the direction from the center of gravity
64b toward the first strain sensing element 50A intersects with the direction from the center of
gravity 64b toward the second strain sensing element 50B. In this example, the direction from
the center of gravity 64b to the first strain sensing element 50A is perpendicular to the direction
from the center of gravity 64b to the second strain sensing element 50B. For example, a straight
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line passing through the first strain sensing element 50A and the center of gravity 64b passes
through the strain sensing element 50c. For example, a straight line passing through the second
strain sensing element 50B and the center of gravity 64b passes through the strain sensing
element 50d.
[0019]
FIG. 3A to FIG. 3D are schematic plan views illustrating a part of the pressure sensor according to
the first embodiment. These figures illustrate the shape of the film surface 64 a of the
transducing thin film 64. As shown in FIGS. 3A to 3D, the shape of the film surface 64a (a
bending portion) of the transducing thin film 64 is a circle, a flat circle (including an ellipse), a
square or a rectangle, etc. . In such a case, the center of gravity of the film surface 64a is the
center of a circle, the center of an ellipse, the center of a diagonal of a square, or the center of a
diagonal of a rectangle.
[0020]
The transducing thin film 64 is formed of, for example, an insulating layer. Alternatively, the
transducing thin film 64 is formed of, for example, a metal material. The transducing thin film 64
includes, for example, silicon oxide or silicon nitride. The thickness of the transducing thin film
64 is, for example, 200 nm or more and 3 μm or less. Preferably, it is 300 nm or more and 1.5
μm or less. The diameter of the transducing thin film 64 is, for example, 1 μm or more and 600
μm or less. More preferably, they are 60 micrometers or more and 600 micrometers or less. The
transducing thin film 64 is, for example, flexible in the Z-axis direction perpendicular to the film
surface 64a.
[0021]
In this example, the fixing portion 67 includes fixing portions 67a to 67d. As shown in FIG. 2, in
this example, the fixing parts 67 a and 67 c are disposed at the intersections of the straight line
64 c and the edge 64 eg of the transducing thin film 64. The straight line 64 c passes the center
of gravity 64 b of the film surface 64 a of the transducing thin film 64 and is parallel to the Yaxis direction. The fixing portion 67 b and the fixing portion 67 d are disposed at the intersection
of the straight line 64 d and the edge 64 eg of the transducing thin film 64. The straight line 64
d passes through the center of gravity 64 b of the film surface 64 a of the transducing thin film
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64 and is parallel to the X-axis direction. The fixing portions 67a to 67d fix the transducing thin
film 64 to the non-hollow portion 71 (base 71a). The fixing portions 67a to 67d include, for
example, silicon which is a part of the substrate material, the same material as the transducing
thin film formed on the substrate material, and the like. The fixing portions 67a to 67d are
portions formed to have a film thickness thicker than the transducing thin film 64 so as to be
hardly bent even when an external pressure is applied.
[0022]
One end of each of the strain sensing elements 50 a to 50 d is connected to the first wiring 57.
The other end of each of the strain sensing elements 50 a to 50 d is connected to the second
wiring 58.
[0023]
The first wiring 57 and the second wiring 58 extend from the strain sensing element 50 toward
the base 71 a on the fixing portion 67 or through the inside of the fixing portion 67.
[0024]
FIG. 4 is a schematic perspective view illustrating a part of the pressure sensor according to the
first embodiment.
FIG. 4 shows an example of the configuration of the strain sensing element 50. As shown in FIG.
As shown in FIG. 4, the strain resistance change unit 50s (the strain sensing element 50 and the
first strain sensing element 50A) includes, for example, the first magnetic layer 10, the second
magnetic layer 20, and the first magnetic layer. And an intermediate layer 30 (first intermediate
layer) provided between the second magnetic layer 20 and the second magnetic layer 20. The
intermediate layer 30 is a nonmagnetic layer. The configuration of each of the plurality of strain
sensing elements 50 is also similar to that described above. The direction of magnetization of the
first magnetic layer 10 is variable. The first magnetic layer 10 is a magnetization free layer. The
direction of magnetization of the second magnetic layer 20 is substantially fixed. The second
magnetic layer 20 is a magnetization fixed layer.
[0025]
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For example, the second strain sensing element 50B includes the nonmagnetic second
intermediate layer 30B provided between the third magnetic layer 10B, the fourth magnetic layer
20B, and the third magnetic layer 10B and the fourth magnetic layer 20B. And. The configuration
of the third magnetic layer 10B is the same as the configuration of the first magnetic layer 10. As
described later, the direction of magnetization of the fourth magnetic layer 20B is different from
the direction of magnetization of the second magnetic layer 20. Other than this, the configuration
of the fourth magnetic layer 20B is the same as the configuration of the second magnetic layer
20. The configuration of the second intermediate layer 30B is the same as the configuration of
the first intermediate layer 30. The direction of magnetization of the third magnetic layer 10B is
variable. The third magnetic layer 10B is a magnetization free layer. The direction of
magnetization of the fourth magnetic layer 20B is substantially fixed. The fourth magnetic layer
20B is a magnetization fixed layer.
[0026]
The same configuration as the first magnetic layer 10, the second magnetic layer 20, and the
intermediate layer 30 described below can be applied to the third magnetic layer 10B, the fourth
magnetic layer 20B, and the second intermediate layer 30B. In the strain sensing element 50, the
“inverse magnetostrictive effect” of the ferromagnetic material and the “MR effect”
exhibited in the strain resistance change portion 50s are used. The “MR effect” is a
phenomenon in which in the laminated film having a magnetic body, when an external magnetic
field is applied, the value of the electrical resistance of the laminated film changes due to the
change in the magnetization of the magnetic body. The MR effect includes, for example, a GMR
(Giant magnetoresistance) effect or a TMR (Tunneling magnetoresistance) effect. By supplying a
current to the strain resistance change unit 50s, the MR effect is expressed by reading the
change in the relative angle of the magnetization direction as the change in electrical resistance.
For example, based on the stress applied to the strain sensing element 50, a tensile stress is
applied to the strain resistance change portion 50s. When the direction of the magnetization of
the first magnetic layer 10 is different from the direction of the tensile stress applied to the
second magnetic layer 20, the MR effect is exhibited due to the inverse magnetostrictive effect.
Assuming that the resistance in the low resistance state is R and the amount of change in
electrical resistance that changes due to the MR effect is ΔR, ΔR / R is called “MR change
rate”.
[0027]
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FIG. 5A to FIG. 5C are schematic perspective views illustrating the operation of the pressure
sensor according to the first embodiment. These drawings illustrate the state of the strain
sensing element 50. These drawings illustrate the relationship between the magnetization
direction in the strain sensing element 50 and the direction of tensile stress.
[0028]
FIG. 5A shows a state in which no tensile stress is applied. At this time, in this example, the
direction of the magnetization of the second magnetic layer 20 (the magnetization fixed layer) is
the same as the direction of the magnetization of the first magnetic layer 10 (the magnetization
free layer).
[0029]
FIG. 5 (b) shows a state in which a tensile stress is applied. In this example, tensile stress is
applied along the X-axis direction. For example, deformation of the transducing thin film 64
applies tensile stress along the X-axis direction. That is, the tensile stress is applied in a direction
orthogonal to the magnetization directions (in this example, the Y-axis direction) of the second
magnetic layer 20 (the magnetization fixed layer) and the first magnetic layer 10 (the
magnetization free layer). At this time, the magnetization of the first magnetic layer 10 (the
magnetization free layer) is rotated so as to be in the same direction as the direction of the
tensile stress. This is called "inverse magnetostriction effect". At this time, the magnetization of
the second magnetic layer 20 (the magnetization fixed layer) is fixed. Therefore, the
magnetization of the first magnetic layer 10 (magnetization free layer) is rotated, whereby the
direction of magnetization of the second magnetic layer 20 (magnetization fixed layer) and the
direction of magnetization of the first magnetic layer 10 (magnetization free layer) are obtained.
The relative angle between and changes.
[0030]
In this drawing, the magnetization direction of the second magnetic layer 20 (the magnetization
fixed layer) is illustrated as an example, and the magnetization direction may not be the direction
shown in this drawing.
[0031]
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In the inverse magnetostrictive effect, the easy axis of magnetization changes depending on the
sign of the magnetostriction constant of the ferromagnetic body.
Many materials that exhibit large inverse magnetostrictive effects have positive magnetostriction
constants. When the magnetostriction constant is a positive sign, as described above, the
direction in which the tensile stress is applied is the easy magnetization axis. At this time, as
described above, the magnetization of the first magnetic layer 10 (the magnetization free layer)
rotates in the direction of the magnetization easy axis.
[0032]
For example, when the magnetostriction constant of the first magnetic layer 10 (magnetization
free layer) is positive, the magnetization direction of the first magnetic layer 10 (magnetization
free layer) is set to a direction different from the direction in which tensile stress is applied. . On
the other hand, when the magnetostriction constant is negative, the direction perpendicular to
the direction in which the tensile stress is applied is the easy magnetization axis.
[0033]
FIG. 5C exemplifies a state where the magnetostriction constant is negative. In this case, the
magnetization direction of the first magnetic layer 10 (magnetization free layer) is set to a
direction different from the direction perpendicular to the direction in which tensile stress is
applied (in this example, the X-axis direction).
[0034]
In this drawing, the magnetization direction of the second magnetic layer 20 (the magnetization
fixed layer) is illustrated as an example, and the magnetization direction may not be the direction
shown in this drawing.
[0035]
Depending on the angle between the magnetization of the first magnetic layer 10 and the
magnetization of the second magnetic layer 20, the electrical resistance of the strain sensing
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element 50 (the strain resistance change unit 50s) changes, for example, due to the MR effect.
[0036]
The magnetostriction constant (λs) indicates the magnitude of the change in shape when the
external magnetic field is applied to saturate the ferromagnetic layer in a certain direction.
Assuming that the length is L in the absence of an external magnetic field, the magnetostriction
constant λs is represented by ΔL / L, assuming that it changes by ΔL when the external
magnetic field is applied.
The amount of change varies depending on the magnitude of the magnetic field, but the
magnetostriction constant λs is expressed as ΔL / L in a state where the sufficient magnetic
field is applied and the magnetization is saturated.
[0037]
For example, the second magnetic layer 20 contains at least one of Fe, Co and Ni. For example,
for the second magnetic layer 20, Fe, Co, Ni or an alloy material thereof is used. For the second
magnetic layer 20, a material obtained by adding an additive element to the above-described
material is used. For the second magnetic layer 20, for example, a CoFe alloy, a CoFeB alloy, a
NiFe alloy or the like can be used. The thickness of the second magnetic layer 20 is, for example,
not less than 2 nanometers (nm) and not more than 6 nm.
[0038]
For the intermediate layer 30, a metal or an insulator can be used. As the metal, for example, Cu,
Au, Ag or the like can be used. In the case of metal, the thickness of the intermediate layer 30 is,
for example, 1 nm or more and 7 nm or less. As the insulator, for example, magnesium oxide
(such as MgO), aluminum oxide (such as Al 2 O 3), titanium oxide (such as TiO), and zinc oxide
(such as ZnO) can be used. In the case of an insulator, the thickness of the intermediate layer 30
is, for example, 1 nm or more and 3 nm or less.
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[0039]
For the first magnetic layer 10, for example, an alloy material containing at least one of Fe, Co,
and Ni, or at least these is used. The material which added the additional element to said material
is used.
[0040]
For the first magnetic layer 10, a material having a large magnetostriction is used. Specifically, a
material whose absolute value of magnetostriction is larger than 10 <-5> is used. Thereby, the
magnetization is sensitive to strain. For the first magnetic layer 10, a material having positive
magnetostriction may be used, or a material having negative magnetostriction may be used.
[0041]
The first magnetic layer 10 contains, for example, at least one of Fe, Co and Ni. For the first
magnetic layer 10, for example, a FeCo alloy, a NiFe alloy or the like can be used. Besides, in the
first magnetic layer 10, an Fe--Co--Si--B alloy, a Tb-M--Fe alloy showing λs> 100 ppm (M is Sm,
Eu, Gd, Dy, Ho, Er), Tb- M1-Fe-M2 alloy (M1 is Sm, Eu, Gd, Dy, Ho, Er, M2 is Ti, Cr, Mn, Co, Cu,
Nb, Mo, W, Ta), Fe-M3-M4- B alloy (M3 is Ti, Cr, Mn, Co, Cu, Nb, Mo, W, Ta, M4 is Ce, Pr, Nd, Sm,
Tb, Dy, Er), Ni, Al-Fe or ferrite ( Fe 3 O 4, (FeCo) 3 O 4) and the like can be used. The thickness of
the first magnetic layer 10 is, for example, 2 nm or more.
[0042]
The first magnetic layer 10 can have a two-layer structure. In this case, the first magnetic layer
10 can include a layer of FeCo alloy, and the following layers stacked with a layer of FeCo alloy.
An Fe-Co-Si-B alloy, a Tb-M-Fe alloy showing λs> 100 ppm (M is Sm, Eu, Gd, Dy, Ho, Er), Tblaminated with a layer of FeCo alloy M1-Fe-M2 alloy (M1 is Sm, Eu, Gd, Dy, Ho, Er, M2 is Ti, Cr,
Mn, Co, Cu, Nb, Mo, W, Ta), Fe-M3-M4- B alloy (M3 is Ti, Cr, Mn, Co, Cu, Nb, Mo, W, Ta, M4 is Ce,
Pr, Nd, Sm, Tb, Dy, Er), Ni, Al-Fe or ferrite ( It is a layer of a material selected from Fe 3 O 4,
(FeCo) 3 O 4) and the like.
05-05-2019
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[0043]
For example, when the intermediate layer 30 is a metal, the GMR effect appears. When the
intermediate layer 30 is an insulator, the TMR effect is exhibited. For example, in the strain
sensing element 50, for example, a CPP (Current Perpendicular to Plane) -GMR effect of causing
a current to flow along the stacking direction of the strain resistance change unit 50s is used.
[0044]
Further, a CCP (Current-Confined-Path) spacer layer in which a plurality of metal current paths
having a width (for example, diameter) of about 1 nm or more and 5 nm are penetrated in part in
the insulating layer as the intermediate layer 30 is formed. Can be used. Again, the CCP effect is
used.
[0045]
Thus, in the present embodiment, the inverse magnetostriction phenomenon in the strain sensing
element 50 is used. This enables highly sensitive detection. When the inverse magnetostrictive
effect is used, for example, the magnetization direction of the first magnetic layer 10 changes
with respect to externally applied strain. The relative angle between the magnetizations of the
two magnetic layers changes depending on the externally applied strain (such as the presence or
absence and the degree thereof). The strain sensing element 50 functions as a pressure sensor
because the electrical resistance is changed by externally applied strain.
[0046]
In the strain sensing element 50, the spin of the magnetic layer is used. The area required for the
strain sensing element 50 is sufficient for a very small size. For example, when considering the
size of a square, the strain sensing element 50 may have a length of 10 nm × 10 nm to 20 nm
× 20 nm or more on one side.
[0047]
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The area of the strain sensing element 50 is made sufficiently smaller than the area of the
transducing thin film 64 deflected by pressure. Here, the transducing thin film is a portion which
is surrounded by the fixed end as described above, is thinner than the fixed end at a certain
thickness, and is bent by an external pressure. Specifically, the area of the strain sensing element
50 is 1⁄5 or less of the area of the transducing thin film 64 in the substrate plane. In general, the
size of the transducing thin film 64 is about 60 μm or more and 600 μm or less as described
above. When the diameter of the transducing thin film 64 is as small as about 60 μm, the length
of one side of the strain sensing element 50 is, for example, 12 μm or less. When the diameter
of the transducing thin film is 600 μm, the length of one side of the strain sensing element 50 is
120 μm or less. This value is, for example, the upper limit of the size of the strain sensing
element 50.
[0048]
As compared with the value of the upper limit, the above-mentioned size of 10 nm or more and
20 nm or less of one side is extremely small. For this reason, in consideration of the processing
accuracy of the element, the necessity of excessively reducing the size of the strain sensing
element 50 does not occur. Therefore, it is practically preferable that the size of one side of the
strain sensing element 50 be, for example, about 0.5 μm to 20 μm. If the element size becomes
extremely small, the magnitude of the demagnetizing field generated in the strain sensing
element 50 becomes large, which may make bias control of the strain sensing element 50
difficult. As the element size increases, the problem of the demagnetizing field does not occur,
which makes it easy to handle from an engineering point of view. From that point of view, as
described above, 0.5 μm or more and 20 μm or less is a preferable size.
[0049]
For example, the length of the strain sensing element 50 along the X-axis direction is 20 nm or
more and 10 μm or less. The length of the strain sensing element 50 in the X-axis direction is
preferably 200 nm or more and 5 μm or less.
[0050]
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For example, the length of the strain sensing element 50 along the Y-axis direction
(perpendicular to the X-axis direction and parallel to the XY plane) is 20 nm or more and 10 μm
or less. The length of the strain sensing element 50 in the Y-axis direction is preferably 200 nm
or more and 5 μm or less.
[0051]
For example, the length along the Z-axis direction (direction perpendicular to the XY plane) of the
strain sensing element 50 is 20 nm or more and 100 nm or less.
[0052]
The length of the strain sensing element 50 in the X-axis direction may be the same as or
different from the length of the strain sensing element 50 in the Y-axis direction.
When the length of the strain sensing element 50 in the X-axis direction is different from the
length of the strain sensing element 50 in the Y-axis direction, shape magnetic anisotropy occurs.
Thereby, the same function as the function obtained in the hard bias layer can be obtained.
[0053]
The direction of the current flowed in the strain sensing element 50 may be a direction from the
first magnetic layer 10 to the second magnetic layer 20 or may be a direction from the second
magnetic layer 20 to the first magnetic layer 10.
[0054]
6A to 6C are schematic perspective views illustrating a part of the pressure sensor according to
the first embodiment.
As shown in FIG. 6A, the strain sensing element 50 (first strain sensing element 50A) includes,
for example, a first electrode 51 (first electrode 51a) and a second electrode 52 (second
electrode 52a). ,including. A strain resistance change unit 50s (strain resistance change unit
50sa) is provided between the first electrode 51 and the second electrode 52. In this example, in
the strain resistance change unit 50s, the first magnetic layer 10 is provided between the first
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16
electrode 51 and the second electrode 52. The second magnetic layer 20 is provided between the
first electrode 51 and the first magnetic layer 10. An intermediate layer 30 (first intermediate
layer) is provided between the first magnetic layer 10 and the second magnetic layer 20. The
buffer layer 41 (first buffer layer 41 a) is provided between the first electrode 51 and the second
magnetic layer 20. An antiferromagnetic layer 42 (first antiferromagnetic layer 42 a) is provided
between the buffer layer 41 and the second magnetic layer 20. The ferromagnetic layer 43 (first
ferromagnetic layer 43 a) is provided between the antiferromagnetic layer 42 and the second
magnetic layer 20. A film 44 (first film 44 a) is provided between the ferromagnetic layer 43 and
the second magnetic layer 20. A cap layer 45 (first cap layer 45 a) is provided between the first
magnetic layer 10 and the second electrode 52.
[0055]
That is, the first strain sensing element 50A is provided on the first surface, and the first
magnetic layer 10, the second magnetic layer 20, the first intermediate layer 30, the first film
44a, and the first ferromagnetic layer are provided. 43a and a first antiferromagnetic layer 42a.
The second magnetic layer 20 is provided between the first magnetic layer 10 and the first film
44 a. The first film 44a is provided between the second magnetic layer 20 and the first
ferromagnetic layer 43a. The first ferromagnetic layer 43a is provided between the second
magnetic layer 20 and the first antiferromagnetic layer 42a.
[0056]
As shown in FIG. 6B, the strain sensing element 50 (second strain sensing element 50B) includes,
for example, a first electrode 51 (first electrode 51b) and a second electrode 52 (second
electrode 52b). ,including. The strain resistance change unit 50s (strain resistance change unit
50sb) is provided between the first electrode 51 and the second electrode 52. In this example, in
the strain resistance change unit 50s, the third magnetic layer 10B is provided between the first
electrode 51 and the second electrode 52. The fourth magnetic layer 20B is provided between
the first electrode 51 and the third magnetic layer 10B. The second intermediate layer 30B is
provided between the third magnetic layer 10B and the fourth magnetic layer 20B. The buffer
layer 41 (second buffer layer 41 b) is provided between the first electrode 51 and the fourth
magnetic layer 20B. The antiferromagnetic layer 42 (second antiferromagnetic layer 42 b) is
provided between the buffer layer 41 and the fourth magnetic layer 20B. A ferromagnetic layer
43 (second ferromagnetic layer 43b) is provided between the antiferromagnetic layer 42 and the
fourth magnetic layer 20B. A film 44 (second film 44b) is provided between the ferromagnetic
layer 43 and the fourth magnetic layer 20B. A cap layer 45 (second cap layer 45 b) is provided
05-05-2019
17
between the first magnetic layer 10 and the second electrode 52. That is, the second strain
sensing element 50B is provided on the first surface and is separated from the first strain sensing
element 50A. The second strain sensing element 50B includes a third magnetic layer 10B, a
fourth magnetic layer 20B, a second intermediate layer 30B, a second film 44b, a second
ferromagnetic layer 43b, and a second antiferromagnetic layer 42b. And. The fourth magnetic
layer 20B is provided between the third magnetic layer 10B and the second film 44b. The second
film 44b is provided between the fourth magnetic layer 20B and the second ferromagnetic layer
43b. The second ferromagnetic layer 43b is provided between the fourth magnetic layer 20B and
the second antiferromagnetic layer 42b.
[0057]
The buffer layer 41 may also serve as a seed layer. The thickness of the buffer layer 41 is, for
example, 1 nm or more and 10 nm or less. For the buffer layer 41, for example, an amorphous
layer containing at least one of Ta and Ti, or a layer containing at least one of Ru and NiFe is
used. You may use these laminated films. The layer containing at least one of Ru and NiFe is, for
example, a seed layer for promoting crystal orientation.
[0058]
The thickness of the antiferromagnetic layer 42 is, for example, 5 nm or more and 10 nm or less.
The thickness of the ferromagnetic layer 43 is, for example, 2 nm or more and 6 nm or less. The
thickness of the second magnetic layer 20 is, for example, 2 nm or more and 5 nm or less. The
thickness of the intermediate layer 30 is, for example, 1 nm or more and 3 nm or less. The
thickness of the first magnetic layer 10 is, for example, 2 nm or more and 5 nm or less. The
thickness of the cap layer 45 is, for example, 1 nm or more and 5 nm or less.
[0059]
For the first magnetic layer 10, for example, a magnetic laminated film is used. The first magnetic
layer 10 is a magnetic laminated film 10 p (for example, 1 nm or more and 3 nm or less in
thickness) for increasing the MR ratio. For example, an alloy containing CoFe, CoFe, or the like is
used, and a high magnetostrictive magnetic film 10 q (for example, 1 nm or more and 5 nm or
less) provided between the magnetic laminated film 10 p and the cap layer 45.
05-05-2019
18
[0060]
For the first electrode 51 and the second electrode 52, for example, Au, Cu, Ta, Al or the like
which is a nonmagnetic material can be used. By using a soft magnetic material as the first
electrode 51 and the second electrode 52, it is possible to reduce external magnetic noise
affecting the strain resistance change portion 50s. As a material of the soft magnetic body, for
example, permalloy (NiFe alloy) or silicon steel (FeSi alloy) can be used. The strain sensing
element 50 is covered with an insulator such as aluminum oxide (e.g. Al2O3) or silicon oxide (e.g.
SiO2) so that no leak current flows around it.
[0061]
For example, PtMn or IrMn is used for the antiferromagnetic layer 42 (the first antiferromagnetic
layer 42 a and the second antiferromagnetic layer 42 b). The thickness of the antiferromagnetic
layer 42 is, for example, 3 nm or more and 20 nm or less.
[0062]
For example, CoFe is used for the ferromagnetic layer 43 (the first ferromagnetic layer 43a and
the second ferromagnetic layer 43b). The thickness of the ferromagnetic layer 43 is, for example,
1 nm or more and 4 nm or less. The ferromagnetic layer 43 is, for example, a magnetization fixed
layer. The direction of magnetization of the antiferromagnetic layer 42 is, for example, along the
direction of magnetization of the ferromagnetic layer 43.
[0063]
Each of the first film 44 a and the second film 44 b is, for example, NOL (Nano_Oxide Layer). The
thickness of each of the first film 44a and the second film 44b is, for example, 1 nm or more and
4 nm or less.
[0064]
05-05-2019
19
FIG. 6C illustrates another configuration of part of the pressure sensor according to the first
embodiment. As shown in FIG. 6C, the strain sensing element 50 may include bias layers 55a and
55b (hard bias layers). The bias layers 55a and 55b are provided to face the strain resistance
change unit 50s.
[0065]
The bias layers 55 a and 55 b are juxtaposed to the second magnetic layer 20. The strain
resistance change unit 50s is disposed between the bias layers 55a and 55b. An insulating layer
54a is provided between the bias layer 55a and the strain resistance change unit 50s. An
insulating layer 54b is provided between the bias layer 55b and the strain resistance change unit
50s.
[0066]
The bias layers 55 a and 55 b apply a bias magnetic field to the first magnetic layer 10. As a
result, the magnetization direction of the first magnetic layer 10 can be biased to a proper
position, and can be made into a single magnetic domain.
[0067]
The size of each of the bias layers 55a and 55b (in this example, the length along the Y-axis
direction) is, for example, 100 nm or more and 10 μm or less.
[0068]
The size of each of the insulating layers 54a and 54b (in this example, the length along the Y-axis
direction) is, for example, 1 nm or more and 5 nm or less.
[0069]
FIGS. 7A to 7C are schematic perspective views illustrating a part of the pressure sensor
according to the first embodiment.
05-05-2019
20
FIGS. 7A to 7C illustrate the relationship between the oxidation intensity of the film 44 (first film
44a) and the direction of magnetization of the second magnetic layer 20. FIG.
The direction of magnetization of the second magnetic layer 20 changes with the oxidation
intensity of the first film 44a (NOL). The direction of magnetization of the fourth magnetic layer
20B changes with the oxidation intensity of the second film 44b (NOL).
[0070]
FIG. 7A illustrates the case where the oxidation strength of the first film 44a (NOL) is higher than
0 L (Langmuir) and 400 L or less. As shown in FIG. 7A, the direction of the magnetization of the
second magnetic layer 20 is along the direction of the magnetization of the ferromagnetic layer
43. For example, the angle between the direction of the magnetization of the second magnetic
layer 20 and the direction of the magnetization of the ferromagnetic layer 43 is 10 degrees or
less.
[0071]
1 L is a unit related to oxidation strength. 1 L corresponds to the amount formed by exposure to
an atmosphere with an oxygen partial pressure of 1 × 10 6 <-6> Torr for 1 second.
[0072]
FIG. 7B illustrates the case where the oxidation strength of the first film 44a (NOL) is 600 L or
more and 800 L or less. As shown in FIG. 7B, the angle between the direction of the
magnetization of the second magnetic layer 20 and the direction of the magnetization of the
ferromagnetic layer 43 is, for example, about 60 degrees (for example, 50 degrees or more).
Degree or less).
[0073]
05-05-2019
21
FIG. 7C illustrates the case where the oxidation strength of the first film 44a (NOL) is higher than
800 L (in the case of 3000 L or less). As shown in FIG. 7C, the angle between the direction of the
magnetization of the second magnetic layer 20 and the direction of the magnetization of the
ferromagnetic layer 43 is, for example, about 90 degrees (for example, 80 degrees or more and
100 degrees). Degree).
[0074]
Similarly, the direction of magnetization in the fourth magnetic layer 20B of the second strain
sensing element 50B changes with the oxidation intensity. By changing the oxidation intensity of
the film 44 in this manner, it is possible to change the direction of the magnetization of the
second magnetic layer 20 and the direction of the magnetization of the fourth magnetic layer
20B.
[0075]
For example, the oxygen concentration in the first film 44a of the first strain sensing element
50A is a first concentration. For example, the oxygen concentration in the second film 44b of the
second strain sensing element 50B is a second concentration. The second concentration is
different from the first concentration. The embodiment also includes the case where any of the
first film 44a and the second film 44b does not substantially contain oxygen.
[0076]
For example, the first film 44a contains a first valence first metal element and oxygen. The
second film 44 b contains oxygen and a first metal element of a second valence different from
the first valence. The first metal element is, for example, at least one of iron (Fe), chromium (Cr),
nickel (Ni) and manganese (Mn).
[0077]
For example, the first film 44 a contains any one of FeO, Fe 3 O 4, α-Fe 2 O 3 and γ-Fe 2 O 3,
and the second film 44 b contains FeO, Fe 3 O 4 , .Alpha.-Fe.sub.2O.sub.3 and .gamma.Fe.sub.2O.sub.3 which are different from any one of the above.
05-05-2019
22
[0078]
For example, the first film 44a contains any one of CrO, Cr 2 O 3, CrO 2, Cr 2 O 5, CrO 3 and CrO
5, and the second film 44 b contains CrO, Cr 2 O 3 And CrO 2, Cr 2 O 5, CrO 3, and CrO 5, any
one of which is different from any one of the above.
[0079]
For example, the first film 44a contains any one of MnO and MnO 2.
The second film 44 b includes any one of MnO and MnO 2 which is different from any one of the
above.
[0080]
In the present embodiment, the oxidation intensity of the first film 44a included in the first strain
sensing element 50A is different from the oxidation intensity of the second film 44b included in
the second strain sensing element 50B.
Thereby, the direction of the magnetization of the second magnetic layer 20 and the direction of
the magnetization of the fourth magnetic layer 20B can be made different from each other.
[0081]
In the embodiment, as described later, either the oxidation for forming the first film 44a or the
oxidation for forming the second film 44b may be omitted. Thereby, the direction of the
magnetization of the second magnetic layer 20 and the direction of the magnetization of the
fourth magnetic layer 20B can be made different from each other.
[0082]
05-05-2019
23
For example, the oxygen concentration in the first film 44 a is 20 atomic percent (atomic%) or
more and 70 atomic% or less, and the oxygen concentration in the second film 44 b is 0 atomic%
or more and 20 atomic% or less. The value of oxygen concentration in each layer may be
interchanged.
[0083]
Next, an example of the operation of the present embodiment will be described. FIG. 8A and FIG.
8B are schematic views illustrating the operation of the pressure sensor according to the first
embodiment. FIG. 8A is a schematic cross-sectional view when cut along the straight line 64d of
FIG. FIG. 8B is a schematic view illustrating the operation of the pressure sensor.
[0084]
As shown in FIG. 8A, in the pressure sensor 310 according to the present embodiment, the
transducing thin film 64 is bent by receiving a stress 80 from a medium such as air. For example,
stress 81 (for example, a tensile stress) is applied to the transducing thin film 64 by bending the
transducing thin film 64 so that the film surface 64 a is convex. At this time, a stress 81 is also
applied to the strain sensing element 50 provided on the film surface 64 a of the transducing
thin film 64 to cause strain. Thereby, in the strain sensing element 50, the electrical resistance
between one end and the other end of the strain sensing element 50 changes according to the
change in strain amount due to the inverse magnetostrictive effect. When the transducing thin
film 64 bends so that the film surface 64 a is concaved, compressive stress is applied to the
transducing thin film 64.
[0085]
As shown in FIG. 8B, a signal 50sg corresponding to the above stress can be obtained from each
of the plurality of strain sensing elements 50. For example, the first signal sg1 is obtained from
the first strain sensing element 50A. A second signal sg2 is obtained from the second strain
sensing element 50B. The plurality of signals 50 sg are processed by the processing circuit 113.
For example, the plurality of signals 50sg obtained from each of the strain sensing elements 50
are subjected to addition processing.
05-05-2019
24
[0086]
At this time, not only the respective signals are simply added but also addition processing in
which each position is weighted is performed. This makes it possible to obtain a pressure signal
that is favorable for application.
[0087]
For example, the stress sensor according to the embodiment can be applied to an acoustic
microphone or an ultrasonic microphone that acquires a sound wave. At this time, even when the
signals obtained from each of the strain sensing elements 50 are weak, the signals from the
plurality of strain sensing elements 50 are subjected to addition processing to obtain a signal
suitable for amplification processing in the subsequent stage. It becomes possible.
[0088]
FIG. 9A and FIG. 9B are schematic views illustrating the operation of the pressure sensor
according to the first embodiment. FIG. 9A illustrates the first state ST1. FIG. 9B illustrates the
second state ST2.
[0089]
The first state ST1 corresponds to, for example, a state in which no pressure is applied to the
transducing thin film 64 from the outside. The second state ST2 corresponds to, for example, a
state in which the pressure in the Z-axis direction is externally applied to the transducing thin
film 64. In the second state ST2, the transducing thin film 64 is bent so that the film surface 64a
has a convex shape.
[0090]
As shown in FIG. 9A, the direction of magnetization (the second layer magnetization direction
20am) of the second magnetic layer 20 of the first strain sensing element 50A is the direction
05-05-2019
25
from the center of gravity 64b to the first strain sensing element 50A. Cross (for example,
orthogonal). For example, the second layer magnetization direction 20am is along the X-axis
direction.
[0091]
The direction of magnetization of the fourth magnetic layer 20B of the second strain sensing
element 50B (the fourth layer magnetization direction 20bm) intersects (eg, is orthogonal to) the
direction from the center of gravity 64b to the second strain sensing element 50B. For example,
the fourth layer magnetization direction 20bm is along the Y-axis direction.
[0092]
The second layer magnetization direction 20am and the fourth layer magnetization direction
20bm intersect. For example, the second layer magnetization direction 20am and the fourth layer
magnetization direction 20bm are orthogonal to each other. The oxidation intensity of the first
film 44a of the first strain sensing element 50A and the oxidation intensity of the second film
44b of the second strain sensing element 50B are adjusted. That is, the oxygen concentration in
the first film 44a and the oxygen concentration in the second film 44b are adjusted. Thereby, the
second layer magnetization direction 20am and the fourth layer magnetization direction 20bm
can be set as the above directions.
[0093]
The direction of magnetization of the first magnetic layer 10 of the first strain sensing element
50A (first layer magnetization direction 10am) is along the second layer magnetization direction
20am. In this example, the angle between the first layer magnetization direction 10am and the
second layer magnetization direction 20am is about 180 degrees.
[0094]
The direction of magnetization of the third magnetic layer 10B of the second strain sensing
element 50B (third layer magnetization direction 10bm) is along the fourth layer magnetization
05-05-2019
26
direction 20bm. In this example, the angle between the third layer magnetization direction 10bm
and the fourth layer magnetization direction 20bm is about 180 degrees.
[0095]
The second layer magnetization direction 20am and the fourth layer magnetization direction
20bm are substantially fixed. As shown in FIG. 9B, the second layer magnetization direction
20am in the second state ST2 does not substantially change from the second magnetization
direction 20am in the first state ST1. The fourth layer magnetization direction 20bm in the
second state ST2 does not substantially change from the fourth layer magnetization direction
20bm in the first state ST1.
[0096]
In the second state ST2, a tensile stress 81 is applied to the first strain sensing element 50A and
the second strain sensing element 50B. The direction of the stress 81 in the first strain sensing
element 50A is different from the direction of the stress 81 in the second strain sensing element
50B.
[0097]
The direction of the stress 81 (first stress direction 81a) in the first strain sensing element 50A
is, for example, along the direction from the center of gravity 64b to the first strain sensing
element 50A. The first stress direction 81a intersects (eg, is orthogonal to) the second layer
magnetization direction 20am. The first layer magnetization direction 10am in the second state
ST2 is changed by the stress 81 from the first layer magnetization direction 10am in the first
state ST1. The first layer magnetization direction 10am in the second state ST2 changes in the
direction along the first stress direction 81a. Thereby, in the first strain sensing element 50A, the
electrical resistance changes between the first state ST1 and the second state ST2.
[0098]
The direction (second stress direction 81b) of the stress 81 in the second strain sensing element
05-05-2019
27
50B is, for example, along the direction from the center of gravity 64b to the second strain
sensing element 50B. The second stress direction 81 b intersects (eg, is orthogonal to) the fourth
layer magnetization direction 20 bm. The third layer magnetization direction 10bm in the second
state ST2 changes from the third layer magnetization direction 10bm in the first state ST1 by the
stress 81. The third layer magnetization direction 10bm in the second state ST2 changes in the
direction along the second stress direction 81b. Thereby, in the second strain sensing element
50B, the electrical resistance changes between the first state ST1 and the second state ST2.
[0099]
Similarly, in the plurality of strain sensing elements 50 (for example, strain sensing elements 50c
and 50d), the electrical resistance changes between the first state ST1 and the second state ST2.
A signal can be obtained from each of the plurality of strain sensing elements 50. For example,
highly sensitive pressure detection can be realized by adding a plurality of signals.
[0100]
In the embodiment, it is easy to reduce the size of the strain sensing element 50. Thereby, the
plurality of strain sensing elements 50 can be provided on the transducing thin film 64. The
number of strain sensing elements 50 is increased. This improves the SN ratio. A highly sensitive
pressure sensor can be provided.
[0101]
FIG. 10 is a schematic view illustrating a pressure sensor of a reference example. Also in the
pressure sensor 319 of the reference example shown in FIG. 10, the base 71 a and the sensor
unit 72 are provided. The sensor unit 72 includes a transducing thin film 64, a fixing unit 67, a
first strain sensing element 50A, and a second strain sensing element 50B.
[0102]
In the pressure sensor 319, the oxygen concentration in the second film 44b of the second strain
sensing element 50B and the oxygen concentration in the first film 44a of the first strain sensing
05-05-2019
28
element 50A are the same. The configuration described for the pressure sensor 310 can be
applied to the pressure sensor 319 other than this.
[0103]
FIG. 10 corresponds to a state in which the pressure in the Z-axis direction is applied to the
transducing thin film 64 from the outside. The transducing thin film 64 is bent so that the film
surface 64a is convex. In the pressure sensor 319, the oxygen concentration in the first film 44a
and the oxygen concentration in the second film 44b are the same. For this reason, the second
layer magnetization direction 20am and the fourth layer magnetization direction 20bm are the
same. In this example, the fourth layer magnetization direction 20bm is along the X-axis
direction.
[0104]
For example, in a state where no external pressure is applied to the transducing thin film 64, the
first layer magnetization direction 10am is along the second layer magnetization direction 20am.
The third layer magnetization direction 10bm is along the fourth layer magnetization direction
20bm. The first layer magnetization direction 10am and the third layer magnetization direction
10bm are along the X-axis direction.
[0105]
As shown in FIG. 10, when a pressure is applied from the outside, the first layer magnetization
direction 10am changes so as to be along the first stress direction 81a. For example, the first
layer magnetization direction 10am changes along the Y-axis direction. Thereby, the electrical
resistance in the first strain sensing element 50A changes.
[0106]
On the other hand, the second stress direction 81 b and the third layer magnetization direction
10 bm are, for example, parallel. Thereby, the change in the third layer magnetization direction
10bm is small (for example, does not change) even when pressure is applied from the outside.
05-05-2019
29
The change in electrical resistance in the second strain sensing element 50B is small (eg, does
not change). In some cases, a signal corresponding to the pressure can not be obtained from the
second strain sensing element 50B.
[0107]
On the other hand, in the pressure sensor according to the embodiment, the oxygen
concentration in the first film 44a and the oxygen concentration in the second film 44b are
different. By adjusting the oxygen concentration, in each of the plurality of strain sensing
elements, the magnetization direction of the magnetization fixed layer (the second magnetic layer
20) intersects (for example, is orthogonal to) the direction of the stress 81. Thereby, in each of
the plurality of strain sensing elements, a signal corresponding to the pressure can be obtained
with high sensitivity. A highly sensitive pressure sensor can be provided.
[0108]
FIG. 11 is a schematic view illustrating another pressure sensor according to the first
embodiment. Also in the pressure sensor 311, a base 71a and a sensor unit 72 are provided. The
sensor unit 72 includes a transducing thin film 64, a fixing unit 67, and a plurality of strain
sensing elements 50. The configuration described for the pressure sensor 310 can be applied to
the pressure sensor 311.
[0109]
In the embodiment, the number of the plurality of strain sensing elements 50 is arbitrary (at least
two or more). As shown in FIG. 11, in the pressure sensor 311, the number of the plurality of
strain sensing elements 50 provided on the transducing thin film 64 is eight. By increasing the
strain sensing element 50, the SN ratio of the pressure sensor can be improved. Each of the
plurality of strain sensing elements 50 is disposed, for example, on a circumference centered on
the center of gravity 64 b. For example, each of the plurality of strain sensing elements 50 is
disposed at a position equidistant from the position of the center of gravity 64 b.
[0110]
05-05-2019
30
In each of the plurality of strain sensing elements 50, the oxygen concentration of the film 44 is
adjusted. Thereby, the direction of magnetization of the second magnetic layer 20 intersects (for
example, is orthogonal to) the direction from the center of gravity 64 b toward the strain sensing
element 50. Thereby, in each of the plurality of strain sensing elements 50, a signal can be
obtained with high sensitivity.
[0111]
FIG. 12 is a schematic view illustrating another pressure sensor according to the first
embodiment. Also in the pressure sensor 312, a base 71a and a sensor unit 72 are provided. The
sensor unit 72 includes a transducing thin film 64, a fixing unit 67, and a plurality of strain
sensing elements 50. The configuration described for the pressure sensor 310 can be applied to
the pressure sensor 312.
[0112]
As shown in FIG. 12, in this example, the fixing portion 67 is continuous. For example, the fixing
portion 67a is continuous with the fixing portion 67b. The shape of the fixing portion 67 is, for
example, a ring shape, and the fixing portion 67 fixes the transducing thin film 64 along the edge
64eg of the transducing thin film 64. The edge 64eg of the transducing thin film 64 is
continuously fixed.
[0113]
For example, when the fixing portion 67a and the fixing portion 67b are separated, the degree of
deformation of the transducing thin film 64 with respect to the applied pressure becomes large,
and the detection sensitivity becomes high. On the other hand, when the fixing portion 67 is
continuous, the mechanical strength of the fixing portion 67 is increased. As another point of
view, when the sound pressure is detected in the low frequency region, as shown in FIG. 1 or FIG.
2, if there is a hole in the fixing portion 67 (if the fixing portion 67 is not continuous), From
there, the sound waves may also be transmitted to the back side of the transducing thin film 64.
Sound pressure may not be detected correctly. A decrease in sensor sensitivity due to this
phenomenon is called a roll-off phenomenon. When it is intended to sense the low frequency
range of the audible sound, it is not desirable to have such a hole in the fixing portion 67.
05-05-2019
31
Therefore, it is preferable for the microphone to detect the sound wave of the audible sound if
there is no hole in the fixed part as shown in FIG.
[0114]
Moreover, in FIG. 12, although fixing | fixed part 67a-67d and the base | substrate 71a are
drawn as another area | region, you may become integral. In this case, the base 71a itself
becomes the fixing portions 67a to 67d (the fixing portions 67a to 67d are included in the base
71a).
[0115]
The fixing portion 67 is designed in accordance with the thickness of the fixing portion 67, the
required detection sensitivity, and the viewpoint of reliability.
[0116]
FIG. 13 is a schematic view illustrating another pressure sensor according to the first
embodiment.
Also in the pressure sensor 313, a base 71a and a sensor unit 72 are provided. The sensor unit
72 includes a transducing thin film 64, a fixing unit 67, and a plurality of strain sensing elements
50. The configuration described for the pressure sensor 310 can be applied to the pressure
sensor 313.
[0117]
As shown in FIG. 13, shape anisotropy may be provided in each of the strain sensing elements
50. For example, the length (first length Las) of the first strain sensing element 50A along the
direction (first direction) from the center of gravity 64b toward the first strain sensing element
50A, and the direction (first The length (second length Lal) of the first strain sensing element
50A along the two directions is different. In this example, the second length Lal is longer than the
first length Las. Thus, shape anisotropy is provided in the first strain sensing element 50A.
05-05-2019
32
[0118]
For example, the length (third length Lbs) of the second strain sensing element 50B along the
direction from the center of gravity 64b toward the second strain sensing element 50B and the
direction perpendicular to the direction from the center of gravity 64b toward the second strain
sensing element 50B The length (fourth length Lbl) of the second strain sensing element 50B
along the normal direction is different. In this example, the fourth length Lbl is longer than the
third length Lbs.
[0119]
For example, the direction of shape anisotropy in the first strain sensing element 50A is made
different from the direction of shape anisotropy in the second strain sensing element 50B.
Thereby, the second layer magnetization direction 20am and the fourth layer magnetization
direction 20bm can be made different. The sensitivity of each of the strain sensing elements 50
can be increased.
[0120]
According to the embodiment, by adjusting the oxygen concentration of the film 44, the
sensitivity of each of the plurality of strain detection elements 50 can be improved, and a highly
sensitive pressure sensor can be provided.
[0121]
FIG. 14 is a schematic view illustrating another pressure sensor according to the first
embodiment.
As shown in FIG. 14, in the pressure sensor 314 according to the present embodiment, a plurality
of strain sensing elements 50 a are provided between the fixing portion 67 a and the center of
gravity 64 b (first portion 68 a). In this example, some of the plurality of strain sensing elements
50a are arranged along the direction along the edge 64eg. Furthermore, another part of the
strain sensing element 50a is arranged along the direction of a radial straight line (for example,
on the straight line 64c) from the center of gravity 64b to the edge 64eg.
05-05-2019
33
[0122]
In this example, a plurality of strain sensing elements 50b are provided between the fixing
portion 67b and the center of gravity 64b (the second dividing portion 68b). In this example, a
part of the plurality of strain sensing elements 50b is arranged along the direction along the
edge 64eg. Furthermore, another part of the plurality of strain sensing elements 50b is arranged
along a radial straight line direction (for example, on the straight line 64d) from the center of
gravity 64b to the edge 64eg.
[0123]
When stress 81 is applied, strain occurs in each of the first portion 68 a and the second portion
68 b. By providing the plurality of strain sensing elements 50a in the first portion 68a in which
strain occurs in the same direction, the sensitivity is further improved. By providing the plurality
of strain sensing elements 50b in the second portion 68b in which strain in the same direction
occurs, the sensitivity is further improved. The plurality of strain sensing elements 50 may be
connected in series or in parallel.
[0124]
FIG. 15A to FIG. 15C are schematic views illustrating another pressure sensor according to the
first embodiment. These figures show an example of the connection state of connection of a
plurality of strain sensing elements 50 (strain sensing elements 50a). As shown in FIG. 15A, in
the pressure sensor 315a according to the present embodiment, the plurality of strain sensing
elements 50 are electrically connected in series. For example, a plurality of strain sensing
elements 50a are provided on the first portion 68a. At least two of the plurality of strain sensing
elements 50a are electrically connected in series.
[0125]
When the number of strain sensing elements 50 connected in series is N, the obtained electric
signal is N times as many as when the number of strain sensing elements 50 is one. On the other
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hand, thermal noise and Schottky noise become N <1/2> times. That is, the signal-noise ratio
(SNR) is multiplied by N <1/2>. By increasing the number N of strain sensing elements 50
connected in series, the SN ratio can be improved without increasing the size of the transducing
thin film 64.
[0126]
For example, in each of the plurality of strain sensing elements 50a provided in the first portion
68a where the strain sensing element 50a is provided, the change (for example, the polarity) of
the electrical resistance R with respect to the stress 81 is similar. Therefore, it is possible to add
each signal of the several distortion detection element 50a.
[0127]
The bias voltage applied to one strain sensing element 50 is, for example, not less than 50
millivolts (mV) and not more than 150 mV. When N strain sensing elements 50 are connected in
series, the bias voltage is 50 mV × N or more and 150 mV × N or less. For example, in the case
where the number N of strain sensing elements 50 connected in series is 25, the bias voltage is 1
V or more and 3.75 V or less.
[0128]
If the value of the bias voltage is 1 V or more, the design of an electric circuit for processing the
electric signal obtained from the strain sensing element 50 becomes easy, which is practically
preferable. For example, a plurality of strain sensing elements 50 can be provided that produce
an electrical signal of the same polarity when pressure is generated. By connecting these strain
sensing elements in series, the SN ratio can be improved as described above.
[0129]
If the bias voltage (voltage between terminals) exceeds 10 V, it is not desirable in an electric
circuit that processes the electric signal obtained from the strain sensing element 50. In the
embodiment, the number N of strain sensing elements 50 connected in series and the bias
05-05-2019
35
voltage are set so as to be an appropriate voltage range.
[0130]
For example, it is preferable that the voltage when the plurality of strain sensing elements 50 are
electrically connected in series is 1 V or more and 10 V or less. For example, it is applied
between the terminals of the two ends of the plurality of strain sensing elements 50 (the strain
sensing element 50a) electrically connected in series (between the terminal of one end and the
terminal of the other end) Voltage is 1V or more and 10V or less.
[0131]
In order to generate this voltage, when the bias voltage applied to one strain sensing element 50
is 50 mV, the number N of strain sensing elements 50 connected in series is preferably 20 or
more and 200 or less. When the bias voltage applied to one strain sensing element 50 is 150
mV, the number N of strain sensing elements 50 (strain sensing elements 50a) connected in
series is preferably 7 or more and 66 or less.
[0132]
As shown in FIG. 15B, in the pressure sensor 315b according to the present embodiment, a
plurality of strain sensing elements 50 (strain sensing elements 50a) are electrically connected in
parallel. In an embodiment, at least a portion of the plurality of strain sensing elements 50 may
be electrically connected in parallel.
[0133]
As shown in FIG. 15C, in the pressure sensor 314c according to the present embodiment, the
plurality of strain sensing elements 50 (strain sensing elements 50a) form a Wheatstone bridge
circuit. Is connected. Thereby, for example, temperature compensation of detection
characteristics can be performed.
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36
[0134]
Second Embodiment FIG. 16 is a schematic view illustrating a method of manufacturing a
pressure sensor according to a second embodiment. FIG. 17 is a schematic view illustrating the
method for manufacturing a pressure sensor according to the second embodiment. 16 and 17
illustrate a method of manufacturing the pressure sensor 310. FIG.
[0135]
As shown in FIG. 16, in the method of manufacturing the pressure sensor 310, the step of
forming the transducing thin film 64 (step S100), the step of forming the first conductive layer
57a (step S101), and the first laminated film 50AS. (Step S102), the first laminated film 50AS is
patterned (step S103), the second laminated film 50BS is formed (step S104), and the second
laminated film 50BS is patterned (step S104). Step S105), an annealing step (step S106), a step
of forming the second conductive layer 57b (step S107), and a step of etching from the back
surface of the substrate (step S108).
[0136]
As shown in FIG. 17A, in step S100, a transducing film 64fm to be the transducing thin film 64 is
formed on the substrate 70s.
For example, a silicon oxide film is used for the transducing film 64fm. In the case of forming the
fixing portion 67 (for example, the fixing portions 67a to 67d etc.) for intermittently holding the
edge 64eg of the transducing thin film 64, the transducing film 64fm is processed in this step to
form the fixing portion 67. You may form a part.
[0137]
In step S101, a first conductive layer is formed. For example, a conductive film is formed on the
transducing film 64fm (or the transducing thin film 64), and the conductive film is processed into
a predetermined shape to form a first conductive layer. This conductive layer can be, for
example, at least a part of the first wiring 57.
05-05-2019
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[0138]
In step S102, the first stacked film 50AS is stacked on the transducing film 64fm. For example,
step S102 includes a first oxidation step (step S102a) of forming a first oxide film to be a first
film. For example, in step S102, a buffer film, an antiferromagnetic film, a ferromagnetic film, a
first oxide film, a magnetic film, an intermediate film, a magnetic film, and a cap film are stacked
in this order. At this time, the first oxide film is formed by the first oxidation amount (oxidation
strength).
[0139]
As shown in FIG. 17B, in step S103, the first stacked film 50AS is processed (patterned) into a
predetermined shape. The first stacked film 50AS serves as the first strain sensing element 50A.
The first stacked film 50AS can be another strain sensing element 50 provided on a straight line
connecting the position 64p to be the center of gravity 64b and the position at which the first
strain sensing element 50A is disposed. For example, the first stacked film 50AS can also be a
strain sensing element 50c.
[0140]
In step S104, the second stacked film 50BS is stacked on another part of the first conductive
layer. For example, step S104 includes a second oxidation step (step S104a) of forming a second
oxide film to be a second film. For example, in step S104, a buffer film, an antiferromagnetic film,
a ferromagnetic film, a second oxide film, a magnetic film, an intermediate film, a magnetic film,
and a cap film are stacked in this order. At this time, for example, the second oxide film is formed
by the second oxidation amount (oxidation strength). The first oxidation amount (the oxidation
amount in the first oxidation step) and the second oxidation amount (the oxidation amount in the
second oxidation step) are different. In the embodiment, for example, the oxidation strength of
the first oxidation step and the oxidation strength of the second oxidation step are different. For
example, substantially no oxygen may be supplied in any of the first oxidation step and the
second oxidation step. In fact, no oxidation is possible. For example, either of the first oxidation
step and the second oxidation step may be omitted. This is the preferred embodiment to reduce
manufacturing costs.
[0141]
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38
As shown in FIG. 17C, in step S105, the second stacked film 50BS is processed (patterned) into a
predetermined shape. The first stacked film 50BS becomes the second strain sensing element
50B. The second stacked film 50BS can be another strain sensing element 50 provided on a
straight line connecting the position 64p serving as the center of gravity 64b and the position at
which the second strain sensing element 50B is disposed. For example, the second stacked film
50BS can be the strain sensing element 50d.
[0142]
In step S106, annealing in a magnetic field is performed. Thereby, as shown in FIG. 17D, in each
of the plurality of strain sensing elements 50, the magnetization direction of the magnetization
fixed layer (the second magnetic layer 20 and the fourth magnetic layer 20B) is fixed. The
direction of magnetization of the magnetization fixed layer (the second magnetic layer 20 and
the fourth magnetic layer 20B) corresponds to the oxygen concentration of the film 44.
[0143]
In step S107, a conductive film is formed on the strain sensing element 50, and processed into a
predetermined shape. Thereby, the second conductive layer is formed. The second conductive
layer can be, for example, at least a part of the second wiring 58.
[0144]
As shown in FIG. 17E, in step S108, etching is performed from the back surface (lower surface) of
the substrate 70s. For example, Deep-RIE or the like is used for this processing. At this time, the
Bosch process may be performed. Thus, the cavity 70 is formed in the substrate 70s. The portion
where the cavity 70 is not formed is the non-cavity 71. Thereby, the transducing thin film 64 is
formed. When the fixing portion 67 for continuously holding the edge 64eg of the transducing
thin film 64 is formed, the fixing portion 67 is formed simultaneously with the transducing thin
film 64 by performing etching from the back surface of the substrate 70s. .
[0145]
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39
For example, the film formation and patterning of the first laminated film 50AS and the film
formation and patterning of the second laminated film 50BS may be performed simultaneously.
In this case, in the formation of the laminated film to be the plurality of strain sensing elements
50, the step of forming the oxide film is performed a plurality of times. For example, a buffer
film, an antiferromagnetic film, and a ferromagnetic film are formed on the transducing film
64fm. A mask material is formed thereon, and the position where the first strain sensing element
50A is to be formed is opened. The open part is oxidized. Thereby, a first oxide film is formed
(first oxidation step). Thereafter, the mask material is removed and another mask material is
formed thereon. The position where the second strain sensing element 50B is to be formed is
opened. The open part is oxidized. Thereby, a second oxide film is formed (second oxidation
step). The mask material is removed, and a magnetic film, an intermediate film, a magnetic film,
and a cap film are formed in this order on top of that and patterned. Thus, the patterning for
forming the first strain sensing element 50A and the patterning for forming the second strain
sensing element 50B may be performed simultaneously. That is, at least a part of steps S101 to
S107 may be performed simultaneously within the technically possible range, or the order may
be changed.
[0146]
According to the embodiment, the amount of oxidation of the film 44 in each of the plurality of
strain sensing elements 50 is adjusted. Thereby, the sensitivity in each of the plurality of strain
sensing elements 50 can be improved. A highly sensitive pressure sensor can be provided.
[0147]
Third Embodiment FIG. 18 is a schematic view illustrating a microphone according to a third
embodiment. As shown in FIG. 18, the microphone 410 according to the present embodiment
includes an arbitrary pressure sensor according to the embodiment and a pressure sensor of the
deformation thereof. In this example, a pressure sensor 310 is used. The transducing thin film 64
in the pressure sensor 310 inside the microphone 410 is, for example, substantially parallel to
the surface of the portable information terminal 510 on which the display unit 420 is provided.
However, the embodiment is not limited to this, and the arrangement of the transducing thin film
64 is arbitrary.
05-05-2019
40
[0148]
Although the microphone 410 is incorporated in the portable information terminal 510, the
embodiment is not limited thereto. The microphone 410 may be incorporated in, for example, an
IC recorder or a pin microphone.
[0149]
Fourth Embodiment FIG. 19 is a schematic perspective view illustrating an acceleration sensor
according to a fourth embodiment. FIG. 20 is a schematic plan view illustrating the acceleration
sensor according to the fourth embodiment.
[0150]
As shown in FIGS. 19 and 20, the acceleration sensor 330 according to the present embodiment
includes a base 71b, a weight 75, a connection 74, a first strain sensing element 50A, and a
second strain sensing element 50B. ,including. In this example, the acceleration sensor 330
includes a plurality of strain sensing elements (strain sensing elements 50a to 50d). The number
of strain sensing elements may be five or more.
[0151]
The connection part 74 connects the weight part 75 and the base 71b. The connecting portion
74 is deformable in response to a change in the position of the weight portion 75 relative to the
base portion 71 b. The connection portion 74 includes, for example, a first portion 74a and a
second portion 74b. In this example, the connection portion 74 further includes a third portion
74c and a fourth portion 74d.
[0152]
The first strain sensing element 50A (the strain sensing element 50a) is provided on the first
portion 74a. The second strain sensing element 50B (the strain sensing element 50b) is provided
05-05-2019
41
on the second portion 74b. The strain sensing element 50c is provided on the third portion 74c.
The strain sensing element 50d is provided on the fourth portion 74d.
[0153]
The configuration of the first strain sensing element 50A is the same as the configuration of the
first strain sensing element 50A described in the first embodiment. The configuration of the
second strain sensing element 50B is the same as the configuration of the second strain sensing
element 50B described in the first embodiment.
[0154]
The first to fourth portions 74a to 74d are spaced apart from one another. That is, the
connection portion 74 includes a plurality of portions separated from one another. For example,
the connection portion 74 holds a plurality of mutually separated portions of the weight portion
75.
[0155]
For example, the strain sensing elements 50a to 50d are provided substantially in one plane. For
example, a plane parallel to the direction from the first portion 74a to the third portion 74c and
the direction from the second portion 74b to the fourth portion 74d is formed. In this example,
the plane is taken as the XY plane, and the direction perpendicular to the XY plane is taken as
the Z-axis direction.
[0156]
For example, when projected onto the X-Y plane, a line l1 connecting the center of gravity 75c of
the weight portion 75 and the first strain detection element 50A is the center of gravity 75c of
the weight portion 75 and the second strain detection element 50B. Intersect with the line l2
connecting In this example, when projected onto the XY plane, a line l1 connecting the strain
sensing element 50a and the strain sensing element 50c passes through the center of gravity
75c. In this example, when projected onto the X-Y plane, a line 12 connecting the strain sensing
05-05-2019
42
element 50b and the strain sensing element 50d passes through the center of gravity 75c. The
strain sensing elements 50 a to 50 d are arranged along the outer edge 75 r of the weight
portion 75. Embodiments are not limited to this, and the first to fourth portions 74a to 74d may
be continuous. Five or more strain sensing elements may be provided on the connection portion
74.
[0157]
For example, when acceleration is applied to the weight portion 75, the relative position of the
weight portion 75 to the base 71b changes. The connecting portion 74 deforms in response to
the change in the relative position of the weight portion 75 to the base portion 71 b. The
direction of magnetization of the magnetic layer of the strain sensing element (for example, the
first strain sensing element 50A and the second strain sensing element 50B) changes with the
deformation of the connection portion 74. Thereby, for example, the electrical resistance of each
of the plurality of strain sensing elements changes due to the MR effect. The acceleration is
detected by detecting a change in resistance according to the change in the direction of
magnetization of the magnetic layer.
[0158]
The length of the connection portion 74 in the Z-axis direction corresponds to the thickness of
the connection portion 74. The length along the Z-axis direction of the base 71b corresponds to
the thickness of the base 71b. The thickness of the weight 75 along the Z-axis direction
corresponds to the thickness of the weight 75. For example, the thickness of the connection
portion 74 is thinner than the thickness of the base portion 71 b and thinner than the thickness
of the weight portion 75.
[0159]
For example, the length (thickness) of the connection portion 74 (first portion 74a) is shorter
than the length (thickness) of the weight portion 75 in the direction (for example, the Y-axis
direction) from the base 71b to the weight portion 75 thin). For example, the length (width) of
the connection portion 74 (first portion 74 a) in the direction (X-axis direction) perpendicular to
the direction (for example, Y-axis direction) from the base 71 b toward the weight portion 75 is It
is shorter than the length in the Y-axis direction. Thereby, for example, when the weight part 75
05-05-2019
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moves, distortion becomes large (for example, maximum).
[0160]
Thus, for example, the connection portion 74 is more easily deformed than the weight portion
75. In accordance with the change in the position of the weight portion 75, the connection
portion 74 is deformed.
[0161]
Also in the acceleration sensor 330, for example, the oxygen concentration in the first film 44a
and the oxygen concentration in the second film 44b are appropriately adjusted. Thereby, the
direction of magnetization of the magnetization fixed layer is adjusted in each of the plurality of
strain sensing elements. Thus, in each of the plurality of strain sensing elements, a signal
corresponding to the acceleration can be obtained with high sensitivity.
[0162]
According to the embodiment, it is possible to provide a highly sensitive pressure sensor, a
microphone, an acceleration sensor, and a method of manufacturing the pressure sensor.
[0163]
In the present specification, "vertical" and "parallel" include not only strictly vertical and strictly
parallel but also include, for example, variations in manufacturing processes, etc., and they may
be substantially vertical and substantially parallel. Just do it.
[0164]
The embodiments of the present invention have been described above with reference to specific
examples.
However, embodiments of the present invention are not limited to these specific examples.
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For example, a base, a sensor unit, a transducing thin film, a base, a weight, a connection, a first
strain sensing element, a second strain sensing element, a first magnetic layer, a first film, a
second magnetic layer, a first intermediate layer, With respect to the specific configuration of
each element such as the third magnetic layer, the second film, the fourth magnetic layer, and the
second intermediate layer, the present invention can be similarly implemented by appropriately
selecting from known ranges by those skilled in the art. It is included in the scope of the present
invention as long as the same effect can be obtained. Moreover, what combined any two or more
elements of each specific example in the technically possible range is also included in the scope
of the present invention as long as the gist of the present invention is included.
[0165]
In addition, based on the pressure sensor, the microphone and the method of manufacturing the
pressure sensor described above as the embodiment of the present invention, all pressure
sensors, the microphone and the method of manufacturing the pressure sensor can be
appropriately modified and implemented by those skilled in the art. As long as the gist of the
present invention is included, it belongs to the scope of the present invention.
[0166]
Besides, within the scope of the concept of the present invention, those skilled in the art can
conceive of various changes and modifications, and it is understood that the changes and
modifications are also within the scope of the present invention. .
[0167]
While certain embodiments of the present invention have been described, these embodiments
have been presented by way of example only, and are not intended to limit the scope of the
invention.
These novel embodiments can be implemented in various other forms, and various omissions,
substitutions, and modifications can be made without departing from the scope of the invention.
These embodiments and modifications thereof are included in the scope and the gist of the
invention, and are included in the invention described in the claims and the equivalent scope
thereof.
05-05-2019
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[0168]
10: first magnetic layer, 10B: third magnetic layer, 10am: first layer magnetization direction,
10bm: third layer magnetization direction, 10p: magnetic laminated film, 10q: high
magnetostrictive magnetic film, 20: second magnetic layer, 20B: fourth magnetic layer, 20am:
second layer magnetization direction, 20bm: fourth layer magnetization direction, 30: first
intermediate layer, 30B: second intermediate layer, 41: buffer layer, 41a: first buffer layer, 41b
2nd buffer layer 42 antiferromagnetic layer 42a first antiferromagnetic layer 42b second
antiferromagnetic layer 43 43 ferromagnetic layer 43a first ferromagnetic layer 43b second
strong Magnetic layer 44: film 44a: first film 44b: second film 45: cap layer 45a: first cap layer
45b: second cap layer 50: strain detection element 50A: first strain detection Element, 50 AS:
first laminated film, 50 B: second strain sensing element 50BS: second laminated film, 50a to
50d: strain detection element, 50s, 50sa, 50sb: strain resistance change portion, 50sg: signal, 51,
51a, 51b: first electrode, 52, 52a, 52b: second electrode, 54a, 54b: insulating layer, 55a, 55b:
bias layer, 57: first wiring, 57a: first conductive layer, 57b: second conductive layer, 58: second
wiring, 64: transducing thin film, 64a: film surface 64b: Center of gravity, 64c, 64d: Straight line,
64eg: Edge, 64fm: Transducer film, 64p: Position, 67, 67a to 67d: Fixed part, 68a: First part, 68b:
Second part, 70: Cavity Sections 70s: Substrate 71: Non-hollow portion 71a: Base body 71b: Base
portion 72: Sensor portion 74: Connection portion 74a to 74d First to fourth portions 75: Weight
portion 75c: center of gravity, 80, 81: stress, 81a: first stress direction, 81b: second stress
direction, λs: magnetostriction constant, 113: processing circuit, 310 to 313, 314, 315a to
315c, 319: pressure sensor, 330 ... Acceleration sensor, 410 ... Microphone, 420 ... Display unit,
510 ... Personal digital assistant, l1, l2 ... Line, Lal ... 2nd length, Las ... 1st length, Lbl ... 4th
length, Lbs ... 3rd length, S100 ~ S108 ... Step ST1 ... First state ST2 ... Second state sg1 ... First
signal sg2 ... Second signal
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