JP2011038889A - Physical quantity detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-reliability physical quantity detector. <P>SOLUTION: The physical quantity detector includes: a package 10; a reaction substrate 20, having first and second principal surfaces 21 and 22 in a front-to-rear relation and being bendably fixed to the package 10, with the principal surface 22 standing opposite to an inner surface of the package 10; a physical quantity detecting element 30 mounted at least on the first principal surface 21 side of the reaction substrate 20, to generate a signal correspondent to the stress produced in the reaction substrate 20; and a buffer 40 formed on a part of the reaction substrate 20, where the distance between the reaction substrate 20 and the package 10 becomes a minimum, when the reaction substrate 20 is bent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a physical quantity detection device.

  Physical quantity detection devices such as an acceleration sensor and an angular velocity sensor (gyro sensor) are used to control the position and orientation of, for example, an automobile, an aircraft, a rocket, a camera, and a game machine. For example, in a car navigation apparatus, when detecting the current position of a vehicle, an inertial sensor is used to autonomously measure the moving direction and moving distance of the vehicle. Such a physical quantity detection device is required to have sufficiently high reliability.

  As an example of the acceleration sensor, there is a configuration in which a physical quantity detection element is mounted on the surface of a reaction substrate (a part including a beam, a movable part, and a fixed part) that generates stress based on acceleration. For example, in Japanese Patent Application Laid-Open No. 2008-039662, a stress (strain) generated in a reaction substrate supported in a cantilever shape when acceleration is applied is sensed by a double tuning fork vibrating piece (physical quantity detection element), An acceleration sensor for detecting the acceleration is disclosed. The acceleration sensor disclosed in the publication receives an inertial force in which the cone of the reaction substrate is directed in the direction opposite to the direction of acceleration when the acceleration is received, which causes the reaction substrate supported in a cantilever shape to bend. It has a structure.

  On the other hand, the reaction substrate used for the acceleration sensor is preferably formed of a material having a thermal expansion coefficient close to that of the physical quantity detection element for high accuracy. In the publication, both the reaction board and the physical quantity detection element are made of quartz. The acceleration sensor formed by is illustrated.

JP 2008-039662 A

  However, since the reaction substrate is a member that can bend according to an inertial force when the acceleration sensor receives acceleration, when the pulse sensor is applied to the acceleration sensor, for example, the reaction substrate becomes another member. There is a possibility of collision. When such a collision occurs, the reaction substrate may be chipped or damaged.

  Further, when the physical quantity detection device is further reduced in size, the reaction substrate becomes very close to the surface of the package on which the reaction substrate is mounted. Therefore, the reaction substrate and the package are likely to collide with each other, and there is a problem that problems such as breakage of the reaction substrate are more likely to occur.

  An object of some aspects of the present invention is to provide a highly reliable physical quantity detection device.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the physical quantity detection device according to the present invention is:
Package and
A reaction substrate having a first main surface and a second main surface that are in a front-back relationship, being flexibly fixed to the package, and the second main surface facing the inner surface of the package;
A physical quantity detection element mounted on at least the first main surface side of the reaction substrate and generating a signal in accordance with the stress generated in the reaction substrate;
A buffer formed at a portion of the reaction substrate that minimizes the distance between the reaction substrate and the package when the reaction substrate is bent;
including.

  Since such a physical quantity detection device has a buffer, it is suppressed that the reaction substrate directly contacts the package when a large acceleration is applied. In addition, the physical quantity detection device of this application example, when a large acceleration is applied, the reaction substrate collides with the package via a buffer, so that the impact generated on the reaction substrate is mitigated and the reaction substrate is cracked. Etc. can be made difficult to occur. Therefore, the physical quantity detection device according to this application example is not easily damaged and has high reliability.

[Application Example 2]
In application example 1,
The reaction substrate is a physical quantity detection device fixed to the package in a cantilever shape.

  In such a physical quantity detection device, the reaction substrate is fixed in an easily bent state, and the applied physical quantity can be detected with high sensitivity.

[Application Example 3]
In application example 1 or application example 2,
The physical quantity detection device, wherein the buffer is a metal film.

  Such a physical quantity detection device has a buffer that can be easily deformed. Therefore, energy is easily absorbed by deformation of the buffer, and the reaction substrate is further less likely to be damaged and reliability can be improved.

[Application Example 4]
In application example 3,
The physical quantity detection device, wherein the buffer is a sputtered gold film.

  In such a physical quantity detection device, the buffer is formed of dense gold. Therefore, it is possible to further prevent the reaction substrate from being separated (damaged) by impact or the like by covering the reaction substrate with the buffer.

[Application Example 5]
In any one of Application Examples 1 to 4,
The reaction substrate is a substrate that transmits light,
The buffer is a physical quantity detection device that reflects light incident on the reaction substrate.

  Such a physical quantity detection device can optically easily inspect the installation state or operation state of the reaction substrate fixed to the package. Thereby, the physical quantity detection device of this application example can improve measurement accuracy.

The schematic diagram of the cross section of the physical quantity detection apparatus 100 concerning embodiment. The schematic diagram of the cross section of the principal part of the physical quantity detection apparatus 100 concerning embodiment. The top view which shows typically the reaction substrate 20 concerning embodiment. The bottom view which shows typically the reaction substrate 20 concerning embodiment. The schematic diagram of the cross section of the physical quantity detection device 100 concerning embodiment. The schematic diagram of the cross section of the physical quantity detection device 100 concerning embodiment. The bottom view which shows typically the reaction substrate 20 concerning a modification. The bottom view which shows typically the reaction substrate 20 concerning a modification. The schematic diagram of the cross section of the physical quantity detection device 120 concerning embodiment.

  Several preferred embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following embodiment, Various modifications implemented in the range which does not change the summary of this invention are also included.

  The physical quantity detection device 100 of this embodiment includes a package 10, a reaction substrate 20, a physical quantity detection element 30, and a buffer body 40.

  FIG. 1 is a schematic cross-sectional view of the physical quantity detection device 100 of the present embodiment. FIG. 2 is a schematic diagram of a cross section of a main part of the physical quantity detection device 100 of the present embodiment. FIG. 3 is a top view schematically showing the reaction substrate 20. FIG. 4 is a bottom view schematically showing the reaction substrate 20. 1 and 2 include a cross section taken along line AA of FIGS. 3 and 4. FIG.

1. Package The package 10 is configured to be a support for the reaction substrate 20. The package 10 is not limited as long as it has a surface on which the reaction substrate 20 can be fixed. Further, the planar shape of the package 10 can be a polygon, a rectangle, a circle, or a combination thereof. The package 10 may have a cavity 18 that accommodates the reaction substrate 20 and the physical quantity detection element 30. The package 10 may be composed of a plurality of members.

  In the example of the physical quantity detection device 100 illustrated in FIG. 1, the package 10 includes a bottom material 12, a wall material 14, and a lid material 16, and a cavity 18 is formed therein. The reaction substrate 20 and the physical quantity detection element 30 are accommodated in the cavity 18, and the reaction substrate 20 is fixed to the bottom surface of the cavity 18 (the upper surface of the bottom material 12, that is, the inner bottom surface of the package 10). In the example of FIG. 1, the package 10 has a configuration in which a bottom member 12, a wall member 14, and a lid member 16 are joined, but the bottom member 12 and the wall member 14, or the wall member 14 and the lid member 16. May be integrated.

  Examples of the material of the package 10 include various ceramics, crystal, various glasses, and various metals. Further, when the lid member 16 of the package 10 is made of a transparent material such as various kinds of glass, for example, after the package 10 is sealed, the reaction substrate 20 and the physical quantity detection element 30 are irradiated with light from the outside. be able to.

2. Reaction Substrate The reaction substrate 20 has a first main surface 21 and a second main surface 22 that are in a front-back relationship. The reaction substrate 20 is disposed such that the second main surface 22 faces the inner surface of the package 10. Furthermore, the reaction substrate 20 is fixed to the package 10 so that it can be bent.

  The reaction substrate 20 has a flat shape having a first main surface 21 and a second main surface 22 that are in a front-back relationship. The planar shape of the reaction substrate 20 can have, for example, a polygon, a rectangle, a circle, and a combination thereof in plan view. Although the thickness of the reaction substrate 20 is not specifically limited, For example, it can be 1 micrometer or more and 1 mm or less. One of the functions of the reaction substrate 20 is that when a physical quantity such as acceleration is applied to the physical quantity detection device 100, the physical quantity is deflected in the thickness direction so that the physical quantity can be detected by the physical quantity detection element 30. . One of the functions of the reaction substrate 20 is to provide an inertial mass in the physical quantity detection device 100.

  The reaction substrate 20 is fixed to the package 10 so as to be deflectable. The bendable fixation of the reaction substrate 20 means that the reaction substrate 20 is fixed with a portion (fixed portion 24) fixed to the package 10 and a portion (flexible portion 25) not fixed. That is, to be fixed so as to be able to bend is fixed such that stress or strain can be generated in the reaction substrate 20 by inertial force acting on the reaction substrate 20 when a physical quantity such as acceleration is applied to the physical quantity detection device 100. That means. More specifically, as the bendable fixing, the reaction substrate 20 is fixed to the package 10 in a cantilever shape, a doubly supported beam shape, a diaphragm shape, or the like.

  Examples of means for fixing the reaction substrate 20 to the package 10 include bonding by metal bumps and bonding by an adhesive. Thereby, the reaction substrate 20 can be mechanically fixed to the package 10. If bonding by metal bumps is selected, it can also serve as an electrical connection. Furthermore, when using a conductive adhesive when joining with an adhesive, it can also serve as an electrical connection. In the example shown in the drawing, the wiring 60 fixed mechanically by the conductive adhesive layer 70 and formed on the package 10 and the reaction substrate 20 is electrically connected to each other.

  The reaction substrate 20 may have a configuration that makes the reaction substrate 20 easy to bend. As such a configuration, for example, in the thickness direction of the reaction substrate 20, a constricted thin portion (neck portion) is provided to fill the width of the reaction substrate 20. In the example of FIGS. 1 to 4, the reaction substrate 20 has a constricted portion 26. In this example, the constricted portion 26 is formed in the bending portion 25. A plurality of constricted portions 26 may be provided on the reaction substrate 20. The constricted portion 26 is a portion having a small thickness (a portion having a small thickness in sectional view) in the plate-like reaction substrate 20. When the reaction substrate 20 has the constricted portion 26, the reaction substrate 20 is more easily bent when it receives a physical quantity. Accordingly, the sensitivity of the physical quantity detection device 100 to the physical quantity can be further improved.

  The reaction substrate 20 may have appropriate wiring 60 on the first main surface 21 and the second main surface 22. Such wiring 60 can be used, for example, for performing at least one of electrical connection and mechanical connection with the package 10 and the physical quantity detection element 30. Examples of the material of the wiring 60 include metals such as gold, platinum, titanium, aluminum, iridium, and tungsten, and alloys thereof.

  Examples of the material of the reaction substrate 20 include glasses such as silicate glass, semiconductor materials such as silicon and gallium arsenide, metal materials such as stainless steel, various rubbers, polymer materials, crystal, lithium tantalate, and lithium niobate. The piezoelectric material can be used.

  Note that the first main surface 21 and the second main surface 22 are both main surfaces of the reaction substrate 20 and have a front-back relationship. In this specification, for convenience of explanation, an ordinal number is given to each main surface of the substrate, but it does not indicate that the two main surfaces of the substrate are functionally different. In the present embodiment, the second main surface 22 of the reaction substrate 20 is disposed so as to face the inner surface of the package 10 (the upper surface of the bottom material 12), and the physical quantity detection element 30 is disposed on the first main surface 21 side of the reaction substrate 20. Placed.

3. Physical Quantity Detection Element The physical quantity detection element 30 is placed at least on the first main surface 21 side of the reaction substrate 20 and generates a signal according to the stress generated on the reaction substrate 20. The physical quantity detection element 30 can detect stress or distortion (deflection) generated in the reaction substrate 20 when the physical quantity detection device 100 receives a physical quantity such as acceleration. The physical quantity detection element 30 may be further placed on the second main surface 22 side of the reaction substrate 20. In the present embodiment, the physical quantity detection device 100 in which the physical quantity detection element 30 is placed on the first main surface 21 side of the reaction substrate 20 is illustrated.

  Examples of the physical quantity detection element 30 include a piezoresistive element whose electrical resistance value changes with stress, and various vibrating pieces whose resonance frequency changes with stress. Note that the stress and strain (deflection) referred to here are physical quantities related to each other and have a specific correlation. Therefore, stress and strain are equivalent in terms of physical quantities.

  In the physical quantity detection device 100 of the present embodiment, the physical quantity detection element 30 is a double tuning fork vibrating piece. When the physical quantity detection element 30 is formed of a double tuning fork vibrating piece, the distortion or stress of the reaction substrate 20 can be detected with very high accuracy. The physical quantity detection element 30 of the physical quantity detection device 100 of this embodiment has a resonance frequency and can be vibrated at the frequency.

  In this embodiment, the physical quantity detection element 30 is a double tuning fork vibrating piece, and both ends thereof are supported by the reaction substrate 20. In the illustrated example, one end of the physical quantity detection element 30 is fixed to the fixing portion 24 of the reaction substrate 20 supported in a cantilever shape, and the other end is the reaction substrate 20 supported in a cantilever shape. The physical quantity detection element 30 is provided so as to be separated from the first main surface 21 of the reaction substrate 20 and to be bridged in parallel. The physical quantity detection element 30 may be formed separately from the reaction substrate 20 and then connected to the reaction substrate 20 or may be formed integrally with the reaction substrate 20. In the physical quantity detection device 100, the physical quantity detection element 30 is formed separately from the reaction substrate 20, and is fixed to the first main surface 21 side of the reaction substrate 20 by wiring 60 and bumps 80.

  The physical quantity detection element 30 can be formed with an excitation electrode or a wiring 60 drawn from the excitation electrode. Moreover, a land or the like may be formed on the wiring, and can be used for, for example, mechanical connection or electrical connection with the reaction substrate 20.

  Moreover, the physical quantity detection element 30 can further include a configuration for adjusting the vibration frequency. Although not shown, for example, in the vibration region of the physical quantity detection element 30, a mass body for changing the mass of the region can be provided. As such a mass body, a metal vapor deposition film etc. can be mentioned, for example. When a mass body is formed in the vibration region of the physical quantity detection element 30, it can be used for adjusting the vibration frequency of the element. For this reason, even after the physical quantity detection device 100 is completed, the resonance frequency can be adjusted. When such a mass body is formed of a vapor deposition film such as gold or platinum, the mass of the mass body can be reduced by irradiating the mass body with a laser beam, so that the resonance frequency of the physical quantity detection element 30 can be reduced. Can be easily adjusted.

  On the reaction substrate 20, the planar position where the physical quantity detection element 30 is placed is such that when the reaction board 20 is bent due to acceleration or the like, tensile or compressive stress is applied in the longitudinal direction of the physical quantity detection element 30. It is not limited as long as it is placed to occur. In the physical quantity detection device 100, the physical quantity detection element 30 is arranged such that a tensile or compressive stress is generated in the longitudinal direction when the reaction substrate 20 receives acceleration or the like and bends in the thickness direction. When a tensile or compressive stress in the longitudinal direction is generated in the physical quantity detection element 30, the frequency of vibration changes. Therefore, the stress generated in the reaction substrate 20 can be accurately measured by detecting the change in frequency of the vibration. The same applies to the case where the physical quantity detection element 30 is fixed in the form of a doubly supported beam (see FIG. 6).

  As described above, the physical quantity detection element 30 vibrates at a specific frequency, and can signal the stress and strain generated in the reaction substrate 20 due to the change of the frequency in this state. The change in the frequency of vibration of the physical quantity detection element 30 can be measured, for example, by comparison with a reference frequency. Further, if the correlation between the difference between the vibration frequency of the physical quantity detection element 30 and the reference frequency and the magnitude of acceleration or the like is calculated in advance and tabulated, the magnitude of the physical quantity applied to the physical quantity detection device 100 can be more easily obtained. Can be measured.

  Examples of the material of the physical quantity detection element 30 include piezoelectric materials such as quartz, lithium tantalate, and lithium niobate. When the physical quantity detection element 30 is made of crystal, for example, the physical quantity detection element 30 can have the direction connecting the two ends of the physical quantity detection element 30 as the Y-axis direction of the crystal of the crystal. A crystal wafer used when the physical quantity detection element 30 is made of crystal has an orthogonal coordinate system consisting of an X axis, a Y axis, and a Z axis corresponding to the crystal axis of the crystal, and is 0 degrees clockwise around the Z axis. An example is a quartz crystal Z plate that is rotated and cut out within a range of 5 degrees. The quartz crystal Z plate can be obtained by cutting and polishing to a predetermined thickness.

4). Buffer Body The buffer body 40 is formed in a region including a portion where the distance between the reaction substrate 20 and the package 10 is minimized when the reaction substrate 20 is bent. The buffer body 40 is formed on the surface of the reaction substrate 20. The buffer body 40 is in the form of a film or a layer in the present embodiment, but may be a rectangular parallelepiped shape or a dot shape.

  The planar shape of the buffer 40 is not particularly limited. The thickness of the buffer body 40 is not specifically limited, For example, it is 100 nm or more and 100 micrometers or less. One of the functions of the buffer body 40 is to prevent the package 10 and the reaction substrate 20 from contacting each other when the reaction substrate 20 is bent. Further, as one of the functions of the buffer body 40, it is possible to make it difficult to generate cracks or the like in the reaction substrate 20.

  5 and 6 schematically show a state when acceleration is applied to the physical quantity detection device 100 of the present embodiment. FIG. 5 shows an example in which the reaction substrate 20 is fixed in a cantilever shape, and FIG. 6 shows an example in which the reaction substrate 20 is fixed in a cantilever shape.

  As shown in FIGS. 5 and 6, when acceleration is applied to the physical quantity detection device, the reaction substrate 20 bends in the thickness direction. In the illustrated example, an inertial force in the direction of arrow B is generated on the reaction substrate 20 in a state where the acceleration in the direction of arrow A in the drawing is applied to the physical quantity detection device 100, and the bending portion 25 of the reaction substrate 20 The state which bent in the direction of arrow B is shown. In this state, the reaction substrate 20 and the package 10 (bottom material 12) are close to each other at a specific portion as compared to before applying the acceleration. At this time, a tensile stress is generated in the physical quantity detection element 30.

  In the case of the example of FIG. 5, the reaction substrate 20 is supported in a cantilever shape and is bent so that the bending portion 25 approaches the package 10. In this case, the portion where the distance between the reaction substrate 20 and the package 10 is the smallest is the second main surface 22 side of the reaction substrate 20 supported in a cantilever shape, and an approach portion near the tip of the bending portion 25. 27. In addition, as shown in FIG. 6, when the reaction substrate 20 is supported in a doubly-supported beam shape, the reaction substrate 20 is bent so that the vicinity of the center of the bending portion 25 approaches the package 10. In this case, the part where the distance between the reaction substrate 20 and the package 10 is the smallest is the second main surface 22 side of the reaction substrate 20 supported in a doubly-supported beam shape, and the approaching part near the center of the bending part 25 28. At this time, a tensile stress is generated in the physical quantity detection element 30.

  The buffer body 40 is formed in a region including a portion (the above-described proximity portions 27, 28, etc.) where the distance between the reaction substrate 20 and the package 10 is minimized when the reaction substrate 20 is bent. A plurality of buffer bodies 40 can be formed. Moreover, the buffer 40 may be formed in parts other than the approaching part. The region where the buffer 40 is formed is, for example, at an arbitrary position on the second main surface 24 of the reaction substrate 20, an arbitrary position on the first main surface 21, and an arbitrary position on the side surface 23 of the reaction substrate 20. It may be formed. As illustrated in FIGS. 2 and 4, in the physical quantity detection device 100, the buffer body 40 is provided so as to cover the approaching portion 27 of the reaction substrate 20 and a part of the second main surface 22, and further, the reaction substrate. It extends over the side surface 23 of 20.

  Examples of the material of the buffer 40 include metals such as gold, platinum, titanium, aluminum, iridium, and tungsten, and alloys thereof, and resins such as silicone resin, fluororesin, polyamide, and polyimide. When the buffer body 40 is formed of resin, the buffering action against the impact of the reaction substrate 20 can be further enhanced by the flexibility of the buffer body 40. When the buffer 40 is formed of a metal film formed of a metal such as gold, platinum, titanium, aluminum, iridium, tungsten, or an alloy thereof, the buffer 40 and the wiring 60 formed on the reaction substrate 20 are used. Can be formed simultaneously. Further, when gold is selected as the material of the buffer body 40 from the above metals, since gold has flexibility as compared with other metals, it is easy to absorb the shock, and the buffer body 40 has a buffering action against the shock. Can be higher.

  When the buffer 40 is made of metal, the buffer 40 can be formed by a sputtering method, a vapor deposition method, a method of applying a metal paste, or the like. Among these, when the buffer body 40 is formed by the sputtering method, the density of the buffer body 40 increases, and therefore, in addition to the buffer action against impact, the action of suppressing the occurrence of cracks in the reaction substrate 20 can be enhanced.

  The buffer body 40 can also function as an inertial mass of the reaction substrate 20. The buffer body 40 can be provided on the first main surface 21 side of the reaction substrate 20 as a mass body of the bending portion 25. Therefore, it is preferable that the buffer body 40 has a configuration that is widely formed so as to be a region including the area where the package 10 and the reaction substrate 20 contact each other. In this way, the inertial mass of the physical quantity detection device 100 can be increased. For this reason, the sensitivity of the physical quantity detection device 100 can be improved. Further, when the buffer 40 is formed of a vapor deposition film such as gold or platinum, the mass of the buffer 40 can be reduced by irradiating the laser beam, so that the inertial mass of the reaction substrate 20 can be finely adjusted. It can be done easily.

5). As described above, in the physical quantity detection device 100 according to the present embodiment, the buffer 40 is formed at least at a position where the distance between the reaction substrate 20 and the package 10 is minimum when the reaction substrate 20 is bent. ing. For this reason, when a large acceleration is applied to the physical quantity detection device 100, the reaction substrate 20 is prevented from coming into direct contact with the package 10. Further, the physical quantity detection device 100 can alleviate the impact generated on the reaction substrate 20 at this time because the reaction substrate 20 collides with the package 10 via the buffer body 40 when a large acceleration is applied. Cracks and the like are less likely to occur in the reaction substrate 20. Therefore, the physical quantity detection device 100 of the present embodiment is not easily damaged and has high reliability.

6). Modified Examples FIGS. 7 and 8 are bottom views schematically showing modified examples of the reaction substrate 20. FIG. 9 is a schematic view of a cross section of a physical quantity detection device 120 including a reaction substrate according to a modification.

  The reaction substrate 20 can have a plurality of buffer bodies 40 as shown in FIG. In the modification shown in FIG. 7, the buffer body 40 is formed in two places at the end of the approaching portion 27. Even in this case, it can be said that the buffer body 40 is formed at a position where the distance between the reaction substrate 20 and the package 10 is minimum when the reaction substrate 20 is bent. If the buffer body 40 is arranged in this way, it has the effect of buffering the impact described above, and the material can be saved.

  Further, the buffer 40 may be formed so as to cover the main surface of the reaction substrate 20. For example, as shown in FIG. 8, the buffer 40 can be formed so as to cover the bending portion 25 of the second main surface 22 of the reaction substrate 20. When the reaction substrate 20 is made of a material that transmits light (for example, crystal or glass) and the buffer body 40 is disposed on the second main surface 22, the second main surface 22 of the reaction substrate 20 is changed to the first main surface 22. It can function as a mirror that reflects light (for example, laser light) incident from the surface 21 side. Therefore, as shown in FIG. 9, when the light beam L is incident from the first main surface 21 side of the reaction substrate 20, the reflected light beam L is emitted to the first main surface 21 side. Thereby, for example, the inclination of the reaction substrate 20 with respect to the package 10 and the level of the reaction substrate 20 can be optically inspected. Examples of the optical measurement include measurement of the posture of the reaction substrate 20 using the optical Doppler effect, measurement of the deflection (sensitivity) of the reaction substrate 20 with respect to acceleration, and the like.

  Although not shown, even when the buffer body 40 made of metal is formed on the first main surface 21 side of the reaction substrate 20, the buffer body 40 can have a mirror role. It is possible to optically measure the inclination of the substrate 10 with respect to the package 10 and the level of the reaction substrate 20. Even if the buffer body 40 is provided on either the second main surface 22 or the first main surface 21, the reaction substrate 20 is enclosed in the cavity 18 if a transparent material is used for the lid member 16 of the package 10. After that, the above optical measurement becomes possible. By enabling such measurement, the reliability and measurement accuracy of the physical quantity measuring device can be improved.

  Depending on the direction of impact applied to the physical quantity detection device 100 and variations in processing accuracy between individual reaction substrates 20, there is a possibility that the reaction substrate 20 may collide with the package 10 in a slightly twisted state when receiving an impact. possible. In such a case, the location where the reaction substrate 20 collides with the package 10 is not always the same, and may be an unexpected location. Even in the case of such an unexpected collision, in the case of the configuration shown in FIGS. 4 and 8, the buffer body 40 is added along the tip of the bending portion 25, that is, the short side of the bending portion 25 or in addition thereto. Since the structure is formed along the side of the corner portion between the short side and the long side, the buffer body 40 can function effectively.

  The above has been described assuming the case where the second main surface 22 side of the reaction substrate 20 approaches the package 10. The reaction substrate 20 has a physical quantity detection element 30 on the first main surface 21 side. Therefore, the amount of deflection when the reaction substrate 20 bends with the first main surface 21 side as the inner side is often smaller than the amount of deflection with the second main surface 22 as the inner side. However, when the package 10 is made small, the first main surface 21 side of the reaction substrate 20 may be close to the package 10. In this case, if the buffer body 40 is provided on the first main surface 21 side, it is possible to suppress the reaction substrate 20 from coming into direct contact with the package 10 when a large acceleration is applied to the physical quantity detection device 100. In this case, the buffer body 40 may be formed so as to extend over the surface of the physical quantity detection element 30. Thereby, a more reliable physical quantity detection device can be provided.

  The modifications described in the above embodiments and modifications can be applied to the physical quantity detection device of the embodiment singly or in combination with each other. Thereby, the synergistic effect by the independent effect of each deformation | transformation or the combination of each deformation | transformation can be acquired.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same purposes and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

10 ... Package, 12 ... Bottom material, 14 ... Wall material, 16 ... Cover material, 18 ... Cavity,
20 ... reaction substrate, 21 ... first main surface, 22 ... second main surface, 23 ... side surface, 24 ... fixing site,
25 ... Deflection part, 26 ... Constriction part, 27, 28 ... Approaching part, 30 ... Physical quantity detection element,
40 ... buffer, 60 ... wiring, 70 ... conductive adhesive layer, 80 ... bump,
100, 120 ... Physical quantity detection device

Claims (5)

Package and
A reaction substrate having a first main surface and a second main surface that are in a front-back relationship, being flexibly fixed to the package, and the second main surface facing the inner surface of the package;
A physical quantity detection element mounted on at least the first main surface side of the reaction substrate and generating a signal in accordance with the stress generated in the reaction substrate;
A buffer formed at a portion of the reaction substrate that minimizes the distance between the reaction substrate and the package when the reaction substrate is bent;
A physical quantity detection device including: In claim 1,
The reaction substrate is a physical quantity detection device fixed to the package in a cantilever shape. In claim 1 or claim 2,
The physical quantity detection device, wherein the buffer is a metal film. In claim 3,
The physical quantity detection device, wherein the buffer is a sputtered gold film. In any one of Claims 1 thru | or 4,
The reaction substrate is a substrate that transmits light,
The buffer is a physical quantity detection device that reflects light incident on the reaction substrate.

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