JP2010096654A - Pressure sensor, and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensor which reduces a pressure change and a temperature change accompanying measurement. <P>SOLUTION: The pressure sensor includes: a package 12 having a first recession 14 on one surface, and having a second recession 16 on the other surface; a pressure sensor element 26 which is arranged in the first recession 14 and uses a piezoelectric vibrating reed as a pressure-sensitive element; and a temperature compensation circuit 52 which is arranged in the second recession 16, is connected to the sensor element 26 electrically, and compensates a pressure measurement error of the pressure sensor due to a change in temperature. The compensation circuit 52 is adhered to spacers 18 provided on the peripheral edges of the bottom part 16a of the second recession 16, and is arranged while being spaced apart from the bottom part 16a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure sensor, and more particularly to a technique for reducing the influence of heat from a circuit connected to a pressure sensor element and reducing the volume of the pressure sensor, and a manufacturing technique thereof.

  In recent years, pressure sensors are required to have high accuracy as well as downsizing. In order to meet such requirements, Patent Document 1 discloses a capacitance change type pressure sensor element, a case in which the pressure sensor element is housed and a pressure introduction path for introducing a measurement pressure is provided. A gas pressure sensor is disclosed that includes a signal processing circuit that converts a capacitance of the pressure sensor element into a predetermined electrical signal. As shown in FIG. 10 (FIG. 10A is an overall view and FIG. 10B is a partial detail view), the pressure sensor 201 according to Patent Document 1 is formed of a semiconductor that receives and displaces a pressure to be measured. Diaphragm 231, insulators 232 and 233 made of glass or the like that sandwich diaphragm 231 from both sides, and electrodes facing insulators 232 and 233, and electrodes for converting displacement of diaphragm 231 into capacitance Is formed on a shield material 216 made of Kovar (nickel alloy) in a synthetic resin (plastic) case 210 (consisting of 210A and 210B), and a pressure introduction path The diaphragm 231 is mounted so as to face the communication hole 217 communicating with 214, and signal processing is performed on the printed circuit board 221 in the case 210. IC chip 220 constituting the circuit are mounted. With such a configuration, the pressure sensor element is disposed at a position deviated from the position of the pressure introduction hole provided in the case, and the circuit components constituting the signal processing circuit are disposed in the remaining portion of the case. Since the sensor element and signal processing circuit will be installed in the case, unlike the conventional pressure sensor, which has a stacked structure, the assembly procedure is more flexible and the number of assembly steps can be reduced. As a result, the productivity is improved and the height of the case can be reduced.

As a pressure sensor that can be mounted in place of the pressure sensor element constituting the pressure sensor of Patent Document 1, as shown in FIG. 11, the pressure sensor has a mounting portion on which one of the semiconductor elements 303 is mounted, as shown in FIG. An insulating base 301, a plurality of wiring conductors 305, 305 a, and 305 b disposed on and inside the insulating base 301 and electrically connected to the electrodes of the semiconductor element 303, and the other of the insulating base 301 A capacitance forming electrode 307 that is attached to the central portion of the main surface and electrically connected to one of the wiring conductors 305, 305a, and 305b, and the other main surface is connected to the central portion. A capacitance-forming metal plate 302 is provided which is flexibly bonded to the electrode 307 so as to form a sealed space therebetween and is electrically connected to the other one of the wiring conductors. Pressure Equipment package out is disclosed. With this configuration, the pressure-sensitive element is integrally formed in the package that accommodates the semiconductor element. As a result, the pressure detection device can be reduced in size, and the wiring for connecting the pressure detection electrode and the semiconductor element is short. As an example, unnecessary capacitance generated between these wirings is made small. A capacitance-type pressure sensor similar to that of Patent Document 2 is also disclosed in Patent Document 3.
Japanese Patent No. 3578865 Japanese Patent Laid-Open No. 2002-5766 Japanese Patent Laid-Open No. 7-280683 JP 2007-327922 A

  In Patent Documents 1 to 3, a capacitance forming region and a semiconductor element such as an IC chip are formed close to each other. Therefore, if the state where the pressure sensor module according to Patent Document 1 is operated in the pressure measurement environment in such a state, the semiconductor element generates heat and rises to at least about 35 to 40 ° C. Since the temperature rises from 0 ° C., the pressure sensor is exposed to a high temperature environment, and there is a problem that the pressure value detected by the pressure sensor includes a displacement accompanying the temperature rise.

  Therefore, in order to achieve higher accuracy, it has been proposed to mount a pressure sensor using a piezoelectric element as shown in Patent Document 4 instead of the above-described capacitance type pressure sensor. As shown in FIG. 12 (FIG. 12A is a front view and FIG. 12B is a cross-sectional view taken along line AA in FIG. 12A), in Patent Document 4, a double tuning fork type piezoelectric vibrating piece 408 is provided. The pressure sensor 400 used is formed on the inner wall of the diaphragm 406 in a package base 402, a lid 404 having a diaphragm 406 in the center, and a vacuum sealed internal space 402a formed by the package base 402 and the lid 404. A configuration of a pressure sensor 400 is disclosed in which base portions 408a at both ends of a double tuning fork type piezoelectric vibrating piece 408 are bonded to the projected portion 406a. As a result, when the diaphragm receiving the pressure to be measured is bent, a tensile force is transmitted to the double tuning fork type piezoelectric vibrating piece 408 via the convex portion 406a, so that the double tuning fork type piezoelectric vibrating piece is deformed and a tensile stress is generated. Since a change occurs in the resonance frequency, a change in the resonance frequency of the vibrating arm 408b of the double tuning fork type piezoelectric vibrating piece 408 is detected as a pressure change. Furthermore, by mounting a circuit such as a temperature compensation circuit on the pressure sensor according to Patent Document 4, it is possible to correct a pressure error accompanying a temperature change. However, since the temperature compensation circuit compensates for the difference between the temperature of the pressure measurement environment and the temperature generated by the temperature compensation circuit and the reference temperature, the temperature range in which the temperature compensation is effectively performed is limited. Become.

  On the other hand, the pressure is measured at regular time intervals in order to reduce the power consumption of the pressure sensor. Therefore, when the pressure of the pressure measurement environment is measured, it is performed by docking the closed space formed by the pressure measurement environment at a certain time and the closed space formed by the case of the pressure sensor as shown in Patent Document 1. become. When the closed space of the pressure measurement environment does not have a sufficient size with respect to the closed space formed by the case, when the two closed spaces are docked, the pressure and temperature of the closed space of the pressure measurement environment fluctuate. However, since the temperature in the case also varies with this, there is a problem that it is difficult to accurately measure the pressure in the pressure measurement environment.

  Therefore, the present invention pays attention to the above-mentioned problems, reduces the influence of heat from the circuit connected to the pressure sensor, and suppresses pressure change, temperature change, and pressure sensor temperature change in the pressure measurement environment during pressure measurement. It is an object of the present invention to provide a pressure sensor using the piezoelectric element and a manufacturing method thereof.

  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 application examples.

  Application Example 1 A package having a first recess on one surface and a second recess on the other surface, a pressure sensor element disposed in the first recess and using a piezoelectric vibrating piece as a pressure sensitive element, A temperature compensation circuit disposed in the second recess, electrically connected to the pressure sensor element, and compensating for a pressure measurement error of the pressure sensor accompanying a temperature change, wherein the temperature compensation circuit comprises the first 2. A pressure sensor, which is adhered to a spacer provided at a peripheral edge of a bottom of a recess and is spaced apart from the bottom.

  With the above configuration, the pressure sensor element and the temperature compensation circuit that generates the most heat in one package are separately disposed in the recesses that are formed to face each other in the thickness direction of the package material, and the temperature compensation circuit is floated from the recesses. By arranging in a state, it becomes a pressure sensor that prevents the heat from the temperature compensation circuit from being transmitted to the pressure sensor element while keeping the outer shape of the entire pressure sensor compact.

Application Example 2 The pressure sensor according to Application Example 1, wherein an oscillation circuit that oscillates the pressure sensor element is disposed in the first recess and connected to the pressure sensor element.
As a result, the pressure sensor element can be driven during the manufacture of the pressure sensor, so that a predetermined constant required for the temperature compensation circuit can be calculated and written to the temperature compensation circuit for each pressure sensor element mounted on the package. Thus, a pressure sensor with high temperature compensation accuracy is obtained.

Application Example 3 The pressure sensor according to Application Example 1, wherein a temperature sensor element is disposed in the first recess and connected to the temperature compensation circuit.
As a result, temperature information in the vicinity of the pressure sensor element can be output to the temperature compensation circuit, so that the pressure sensor with reduced pressure measurement error due to temperature change is obtained.

[Application Example 4] The pressure according to any one of Application Examples 1 to 3, wherein the pressure sensor element is disposed via a second spacer provided at a peripheral edge of the bottom of the first recess. Sensor.
Thereby, the pressure sensor element can further reduce the influence of heat from the temperature compensation circuit.

[Application Example 5] The pressure sensor according to Application Example 4, wherein the pressure receiving surface of the pressure sensor element is directed to the bottom side of the first recess.
Thereby, it can avoid that the pressure receiving surface of a pressure sensor element is contaminated with the particle | grains etc. which fly from a to-be-pressure-measured area | region, and can maintain the sensitivity of a pressure sensor element.

Application Example 6 The pressure sensor according to Application Example 4, wherein a gap between the pressure sensor element and the bottom of the first recess is filled with resin.
Since the thermal conductivity of air can vary depending on the pressure, when the pressure of air changes with the above-mentioned gap, the influence of heat on the pressure sensor from the temperature compensation circuit varies. Therefore, as in this application example, by filling the gap with a resin having low thermal conductivity, heat from the temperature compensation circuit to the pressure sensor element through the package is shielded, and from the temperature compensation circuit as in Application Example 3. The effect of heat can be further reduced, and the effect of heat from the temperature compensation circuit is constant regardless of the air pressure. Can be measured.

Application Example 7 The pressure sensor according to any one of Application Examples 1 to 6, wherein the first recess is covered with a lid, and a pressure introduction port is provided in the lid.
Thereby, the internal space formed by the first recess in the package forms a closed space together with the pressure measurement region. Therefore, since the volume on the pressure sensor side can be reduced, a pressure sensor in which the measurement error is reduced by suppressing the pressure change and the temperature change when the internal space and the pressure measurement region are docked is obtained. In particular, by applying this application example to Application Example 6, the volume of the internal space formed by the first recess can be further reduced. Further, when the temperature sensor is not provided in the first recess, the first recess can be designed to be smaller, so that a pressure error and a temperature change during docking can be suppressed to reduce a measurement error.

Application Example 8 The pressure sensor according to Application Example 7, wherein an oscillation circuit that oscillates the pressure sensor element is disposed in the second recess and connected to the pressure sensor element.
The oscillation circuit also generates heat if not as much as the temperature compensation circuit. Therefore, since heat generation can be further suppressed in the first recess, the temperature change can be suppressed and the measurement error can be reduced.

Application Example 9 According to Application Example 7 or 8, wherein a convex portion is provided on a bottom side of the first concave portion of the lid, and the pressure introducing port is communicated with the lid and the convex portion. Pressure sensor.
As a result, the volume of the space formed by the first recess can be further reduced, and the measurement error can be reduced by suppressing the pressure change and the temperature change.

  Application Example 10 A first recess is formed on one surface of a package material, a second recess is formed on the other surface, a spacer is formed on a peripheral edge of the bottom of the second recess, and the first recess and the A penetrating member that is electrically connected to the second recess is passed through, a pressure sensor element having a piezoelectric vibrating piece as a pressure-sensitive element is disposed in the first recess, and is connected to the penetrating member. Measuring the temperature dependence of the resonance frequency of the pressure sensor element from the second recess side to calculate a predetermined constant of a temperature compensation circuit for compensating for the pressure measurement error of the pressure sensor element accompanying a temperature change; The pressure sensor is written, and the temperature compensation circuit is connected to the penetrating member, bonded to the spacer, and arranged away from the bottom.

  As a result, it becomes possible to calculate a predetermined constant in consideration of the characteristics of each pressure sensor element mounted on the package and write it in the temperature compensation circuit, thereby improving the temperature compensation accuracy of the pressure sensors according to Application Examples 1 to 9. be able to.

  Hereinafter, a pressure sensor according to the present invention and a manufacturing method thereof will be described in detail using embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .

FIG. 1 shows a schematic diagram of a pressure sensor according to the first embodiment. 1A is a front view, FIG. 1B is a plan view, and FIG. 1C is a bottom view.
The pressure sensor 10 according to the first embodiment includes a package 12, a pressure sensor element 26, a temperature sensor element 36, a temperature compensation circuit 52, penetrating members 40 and 42, a lid 44, and the like.

The package 12 is formed from a rectangular member made of an insulator such as ceramic, and has a first recess 14 formed on the upper surface and a second recess 16 formed on the lower surface. The first recess 14 and the second recess 16 are formed in a rectangular shape in plan view, and are formed in such a manner that the bottom portions 14a and 16a face each other. Spacers 18 are formed on the periphery (four corners) of the bottom 16 a of the second recess 16. Similarly, the second spacer 20 is also formed on the periphery of the bottom 14 a of the first recess 14. The first substrate 22 on which the temperature compensation circuit is mounted is bonded to the lower end of the spacer 18 with an adhesive or the like. Similarly, the second substrate 24 on which the pressure sensor element 26, the temperature sensor element 36, and the oscillation circuit 38 are mounted is bonded to the upper end of the second spacer 20 with an adhesive or the like. Therefore, gaps 14b and 16b are formed between each substrate and the bottom of each recess. Since the second substrate 24 has a size smaller than the outer shape of the first recess 14 in plan view, the gap 14 b is not spatially separated in the first recess 14.
The pressure sensor element 26 and the temperature sensor element 36 are disposed on the upper surface of the second substrate 24 disposed in the first recess 14, and the oscillation circuit 38 is disposed on the lower surface thereof.

FIG. 2 shows a schematic diagram of the pressure sensor element 26 constituting the first embodiment. 2A is a front view, and FIG. 2B is a plan view.
For example, as shown in FIG. 2, the pressure sensor element 26 is formed by an element package 28, an element lid 32 having a diaphragm 30 at the center, and a double tuning fork type piezoelectric vibrating piece 34. In FIG. 2, the element package 28 and the diaphragm 30 are drawn in a rectangular shape, but may have a circular shape in plan view. The pressure sensor element 26 measures an absolute pressure in which the internal space where the double tuning fork type piezoelectric vibrating piece 34 exists is sealed in a vacuum by the element package 28 and the element lid 32.

  The diaphragm 30 receives pressure from the outside of the pressure sensor element 26 in the direction of the arrow shown in FIG. 2A and bends and deforms to transmit the stress to the double tuning fork type piezoelectric vibrating piece 34. Since the pressure sensor element 26 is based on vacuum, the diaphragm 30 is flat when the outside is vacuum, but when the outside has atmospheric pressure, the diaphragm 30 is bent and deformed toward the inner space.

  The double tuning fork type piezoelectric vibrating piece 34 is made of a piezoelectric material such as quartz, lithium niobate, lithium tantalate, etc., and has a base portion 34a at both ends, and a vibrating arm 34b having a double tuning fork shape between the two base portions 34a. Have An excitation electrode (not shown) is formed on the vibrating arm 34 b, and an extraction electrode (not shown) of the excitation electrode (not shown) is formed on the base 34 a and is electrically connected to the oscillation circuit 38. When an AC voltage is input from the oscillation circuit 38, the vibrating arm 34b vibrates in the direction of the arrow shown in the figure at a predetermined resonance frequency.

  The double tuning fork type piezoelectric vibrating piece 34 has a feature that the vibration state, that is, the resonance frequency is changed by changing the tension applied to the vibrating arm 34b. Specifically, the frequency increases when a pulling force is applied to the vibrating arm 34b, and the frequency decreases when a compression force is applied. The base portions 34a at both ends are respectively connected to convex portions 30a formed on the inner space side of the diaphragm 30. Therefore, due to the bending deformation of the diaphragm 30, the double tuning fork type piezoelectric vibrating piece 34 receives bending stress from the diaphragm 30 and the vibrating arm 34b also bends and deforms. Therefore, the pressure applied to the diaphragm 30 due to the fluctuation of the resonance frequency caused by the deformation is measured. can do. Further, since the resonance frequency varies depending not only on the pressure but also on the temperature, the pressure can be detected with higher accuracy by correcting the pressure error by a temperature compensation circuit described later.

  As the temperature sensor element 36, for example, a tuning fork type piezoelectric vibrating piece (not shown) made of a piezoelectric element as a material is mounted in a metal element package having good thermal conductivity, as described above. In the tuning fork type piezoelectric vibrating piece (not shown), the resonance frequency of the vibrating arm (not shown) fluctuates depending on the temperature, so that the temperature can be calculated from the fluctuation amount of the resonance frequency. The temperature sensor element 36 is mounted on the second substrate 24 together with the pressure sensor element 26. However, in order to measure the temperature of the pressure sensor element 26 more accurately, the temperature sensor element 36 is mounted close to or in contact with the pressure sensor element 26. It is desirable to install. Note that the relationship between the resonance frequency of the temperature sensor element 36 and the temperature is known, and the temperature sensor element 36 converts its resonance frequency into a temperature and outputs it to the temperature compensation circuit 52.

  The oscillation circuit 38 is connected to the pressure sensor element 26 and the temperature sensor element 36 through the through electrodes 38a and 38b, and outputs an alternating voltage for exciting the double tuning fork type piezoelectric vibrating piece 34 and the tuning fork type piezoelectric vibrating piece (not shown). ing. It is assumed that the oscillation circuit 38 is connected to an external power source (not shown) and can output the AC voltage. Further, through holes 24a and 24b are formed in the second substrate 24, and through members 40 and 42 are passed through the through holes 24a and 24b, respectively. A connection electrode 24c formed on the second substrate 24 and connected to the pressure sensor element 26 extends to the through hole 24a. Similarly, the connection electrode 24d connected to the temperature sensor element 36 also extends to the through hole 24b. Electrical connection between the connection electrode 24c and the penetrating member 40, and between the connection electrode 24d and the penetrating member 42 can be performed by soldering because the connection portion faces the outside of the package.

  The penetrating members 40 and 42 (four are used in the present embodiment) are formed of a conductive member such as a metal, and penetrate the package member between the first concave portion 14 and the second concave portion 16, and end portions of the penetrating members 40 and 42 are first. It is being fixed to the package 12 in the aspect exposed to the bottom part 14a of the recessed part 14, and the bottom part 16a of the 2nd recessed part 16, respectively. Therefore, the pressure sensor element is electrically connected to the second recess 16 side via the connection electrode 24c and the penetrating member 40, and the temperature sensor element is respectively connected to the second recess 16 side via the connection electrode 24d and the penetrating member 42.

  A lid 44 is connected to the upper surface of the package 12 so as to seal the first recess 14. A pipe 48 to which a valve 46 is attached is connected to the upper surface of the lid 44, and a pressure inlet 50 is formed in a region where the pipe 48 of the lid 44 is connected. Although not shown, the tip of the pipe 48 is connected to the closed space of the pressure measurement region. Therefore, the closed space formed by the first recess 14 can be connected and separated from the closed space of the pressure measurement region by opening and closing the valve 46.

  On the other hand, a temperature compensation circuit 52 and connection electrodes 22 c and 22 d connected to the temperature compensation circuit 52 are formed on the first substrate 22 disposed in the second recess 16. Through holes 22a and 22b are formed in the first substrate 22 like the second substrate 24, the connection electrode 22c extends to the through hole 22a, the connection electrode 22d extends to the through hole 22b, and the through hole The penetrating member 40 penetrates through 22a, and the penetrating member 42 penetrates through the through hole 22b. Similarly to the second substrate 24, the electrical connection between the connection electrode 22 c and the penetrating member 40 and the electrical connection between the connection electrode 22 d and the penetrating member 42 can also be performed by soldering on the first substrate 22. Therefore, the temperature compensation circuit 52 is electrically connected to the pressure sensor element 26 and the temperature sensor element 36 in the first recess 14.

  The temperature compensation circuit 52 formed by an IC chip or the like calculates a change due to the temperature of the resonance frequency of the pressure sensor element 26 from the temperature information input from the temperature sensor element 36, that is, a pressure measurement error of the pressure sensor 10 due to the temperature change. To compensate.

  The temperature compensation circuit 52 has a built-in function ([Equation 1]) for performing temperature compensation, which is a coefficient of this function and is a constant (matching the temperature characteristics of the pressure sensor element 26 and the temperature sensor element 36). It is necessary to input the temperature coefficient from the outside. Therefore, the temperature compensation circuit 52 is provided with a write terminal 52a and a ground terminal 52b, and these are connected to the writing device 56 (see FIG. 3), whereby the temperature compensation circuit 52 has a constant (temperature) necessary for temperature compensation. The coefficient is input from the writing device and stored in a storage medium (not shown) in the temperature compensation circuit 52.

In order to calculate the temperature coefficient, first, the pressure sensor element 26 is arranged in a chamber in which the pressure can be controlled at room temperature (25 ° C., reference temperature), and the pressure dependence of the resonance frequency of the pressure sensor element 26 in the pressure measurement range. And then the same measurement at several temperature settings, and the resonance frequency f _PT depending on the pressure P and temperature T,
As shown below, C _Pk is made to correspond to a power series with temperature coefficient T and temperature T as a variable, and all plots are substituted,
_CPk that minimizes is calculated by the method of least squares. Here, if the temperature coefficient C _Pk is constant regardless of the pressure P, the temperature coefficient can be set to C _k . This C _k is input to the temperature compensation circuit 52 as a temperature coefficient. Plot data indicating the relationship between the resonance frequency and pressure at the reference temperature is written in a conversion circuit (not shown).

Then, in the temperature compensation circuit 52 includes a temperature T input from the temperature sensor element 36, using a temperature coefficient C _k, are inputted from the pressure sensor element 26, the measured resonance frequency at temperature T, at a reference temperature It converts into the measured resonance frequency, and outputs it to the conversion circuit (not shown) which converts a resonance frequency into a pressure. In the conversion circuit (not shown), since the relationship between the resonance frequency and the pressure at the reference temperature is already input and known, a pressure value corresponding to the input resonance frequency may be output.

  Therefore, the temperature compensation circuit 52 generates a large amount of heat for performing the arithmetic processing. However, the temperature compensation circuit 52 is connected to the package 12 via the spacer 18, and a gap 16 b formed by the spacer 18 is formed between the first substrate 22 on which the temperature compensation circuit 52 is mounted and the package 12. Since the compensation circuit 52 is disposed away from the bottom 16a of the second recess 16, heat from the temperature compensation circuit 52 is prevented from being transferred to the package. Further, a gap 14b formed by the second spacer 20 is also formed between the second substrate 24 on which the pressure sensor element 26 and the like are mounted and the package 12, and the pressure sensor 10 is separated from the bottom 14a of the first recess 14. The pressure sensor element 26 and the like are prevented from receiving heat from the package 12 that is disposed.

  FIG. 3 shows a manufacturing process of the pressure sensor 10 according to the first embodiment. As shown in FIG. 3, in order to form the pressure sensor 10, first, the first recess 14, the second spacer 20, the second recess 16, and the spacer 18 are formed in a rectangular package member 54, and the package 12 is formed. And (b) through holes 40a and 42a through which the through members 40 and 42 are inserted are formed at predetermined positions of the first concave portion 14 and the second concave portion 16 of the package 12, and the through members 40 are inserted into the through holes 40a and 42a. (C) In the first recess 14, the penetrating members 40 and 42 are inserted into the through holes 24a and 24b formed at predetermined positions of the second substrate 24 on which the pressure sensor element 26 and the like are mounted and soldered. Then, the lower surface of the second substrate 24 and the upper surface of the second spacer 20 are bonded with an adhesive or the like, and exposed to the second recess 16 of the penetrating member 40 connected to the pressure sensor element 26 in the second recess 16. And the temperature coefficient necessary for the temperature compensation circuit is calculated by measuring the pressure dependence and temperature dependence of the resonance frequency of the pressure sensor element 26, and (d) the second 2 In the recess 16, the penetration members 40 and 42 are inserted and soldered into the through holes 22 a and 22 b formed at predetermined positions of the first substrate 22, and the upper surface of the first substrate 22 on which the temperature compensation circuit 52 is mounted and the spacer 18 is bonded with an adhesive or the like, and the output side of the writing device is connected to the write terminal 52a and the ground terminal 52b of the temperature compensation circuit 52, so that the temperature is stored in a storage medium (not shown) in the temperature compensation circuit 52. The above-described temperature coefficient necessary for compensation is written, and (e) the lid 44 and the like are connected to the first recess 14.

Here, in the state where the valve 46 is closed, the volume of the closed space in the pressure measurement region is V1, and the volume of the internal space 14c formed by the first recess 14 is V2. For simplicity, it is assumed that the inside of V2 is vacuum before opening the valve 46. At this time, the state equation of the pressure measurement region is as follows.
Here, P ₀ is pressure, n is the number of moles, R is a gas constant, and T ₀ is temperature. The state equation when the valve 46 is opened and the air in the pressure measurement region flows into the internal space 14c formed by the first recess 14 is as follows.
And if it thinks that inflow of gas was performed adiabatically, it has the following relationship.
Here, γ = cp (constant pressure molar specific heat) / cv (constant volume molar specific heat). Therefore, the temperature change T ₁ -T ₀ after opening the valve 46 is as follows.

Therefore, the value of T ₁ -T ₀ closer the V ₂ to zero to approach zero, V ₂ will be where it is preferred to minimize. In particular, when the volume V ₁ of the pressure measurement region is small, it is necessary to design so that V ₂ becomes even smaller. It is possible to reduce the V ₂ described above by sealing the first recess 14 arranged a pressure sensor element 26 in the lid 44 in the first embodiment. A configuration for further reducing the V ₂ will be described in the following embodiment.

  Therefore, according to the pressure sensor 10 according to the first embodiment, the pressure sensor element 26 and the temperature compensation circuit 52 that generates the most heat in one package 12 are formed in a concave portion (first shape) facing each other in the thickness direction of the package material. 1 separately disposed in the recessed portion 14 and the second recessed portion 16), and by arranging the temperature compensation circuit 52 in a state of floating from the recessed portion (second recessed portion 16), Heat from the temperature compensation circuit 52 can be prevented from being transmitted to the pressure sensor element 26, and temperature information in the vicinity of the pressure sensor element 26 can be output to the temperature compensation circuit 52, so that pressure measurement due to a temperature change is performed. The error can be reduced.

  Further, the internal space 14c formed by the first recess 14 with respect to the package 12 forms a closed space together with the pressure measurement region. Therefore, since the volume on the pressure sensor 10 side can be reduced by the lid 44, the measurement error can be reduced by suppressing the pressure change and the temperature change when the internal space 14c and the pressure measurement region are docked. Can do. Furthermore, in the manufacturing process of the first embodiment, a predetermined constant considering the characteristics of each pressure sensor element 26 mounted on the package 12 can be written in the temperature compensation circuit 52, so that the temperature compensation of the pressure sensor 10 can be performed. Can improve the accuracy.

  FIG. 4 shows a schematic diagram of a pressure sensor 60 according to the second embodiment. 4A is a front view, and FIG. 4B is a plan view. The pressure sensor 60 according to the second embodiment is basically the same as that of the first embodiment, except that the second substrate 62 is turned over and connected to the penetrating members 40 and 42, and the oscillation circuit 38 is The second substrate 62 is disposed on the upper surface. Also in the second embodiment, as in the first embodiment, since the connection electrodes 64 and 66 are formed on the upper surface of the second substrate 62, the pressure sensor element 26 and the temperature sensor element 36 are through electrodes 62a and 62b. Are connected to the connection electrodes 64 and 66, respectively. At this time, the diaphragm of the pressure sensor element 26 is directed downward, and the pressure receiving surface is directed to the bottom 14a side of the first recess 14. However, since the gap 14b is not completely partitioned in the internal space 14c as described above, there is no problem in the pressure measurement.

  Thus, by using the pressure sensor 60 as in the second embodiment, the pressure receiving surface of the pressure sensor element is prevented from being contaminated by particles flying from the pressure measurement region, and the sensitivity of the pressure sensor element. Can be maintained.

  5 and 6 are schematic views of pressure sensors 70 and 100 according to the third embodiment. In the pressure sensor 70 of the third embodiment, the oscillation circuit 72 is disposed in the second recess 76 of the package 74, and there are two types. 5 is type 1, FIG. 6 is type 2, FIG. 5 (a) is a front view, FIG. 5 (b) is a plan view, FIG. 5 (c) is a bottom view, and FIG. 6 (a) is a front view. FIG. 6B is a plan view and FIG. 6C is a bottom view.

  As shown in FIG. 5, in the type 1 pressure sensor 70, a spacer 78 has a two-stage structure on the second recess 76 side of the package 74, and a third stage in which an oscillation circuit 72 is mounted on the upper stage 78a of the spacer. A first substrate 84 on which a temperature compensation circuit 82 is mounted is bonded to the substrate 80 and the lower stage 78b. At this time, the oscillation circuit 72 and the pressure sensor element 86 mounted on the second substrate 94 are connected via the connection electrode 80 a connected to the oscillation circuit 72, the penetrating member 88, and the connection electrode 94 a connected to the pressure sensor element 86. The oscillation circuit 72 and the temperature sensor element 92 are connected to each other via the connection electrode 80 b connected to the oscillation circuit 72, the penetrating member 90, and the connection electrode 94 b connected to the temperature sensor element 92.

  The manufacture of the type 1 pressure sensor 70 is the same as in the case of the first embodiment. However, the second substrate 94 on which the pressure sensor element 86 is mounted and the third substrate 80 on which the oscillation circuit is mounted are passed through. After connecting to 40, 42, 88, 90, the pressure dependence and temperature dependence of the resonance frequency of the pressure sensor element are measured.

  As shown in FIG. 6, the type 2 pressure sensor 100 includes an oscillation circuit 102 mounted on a first substrate 106 together with a temperature compensation circuit 104. At this time, the oscillation circuit 102 and the pressure sensor element 108 are connected via the connection electrode 106a connected to the oscillation circuit 102, the penetrating member 110a, and the connection electrode 112a connected to the pressure sensor element 108, and the oscillation circuit 102 and the temperature sensor element 108 are connected to the temperature sensor element 108. The sensor element 114 is connected via the connection electrode 106b connected to the oscillation circuit 102, the penetrating member 110b, and the connection electrode 112b connected to the temperature sensor element 114. The pressure sensor element 108 and the temperature compensation circuit 104 are connected via the connection electrode 112c connected to the pressure sensor element 108, the penetrating member 110c, and the connection electrode 106c connected to the temperature compensation circuit 104. The compensation circuit 104 is connected via a connection electrode 112d connected to the temperature sensor element 114, a penetrating member 110d, and a connection member 106d connected to the temperature compensation circuit.

  According to the pressure sensors 70 and 100 according to the third embodiment (type 1 and type 2), the oscillation circuits 72 and 102 also generate heat, if not as much as the temperature compensation circuits 82 and 104. Therefore, since heat generation in the first recess 96 can be further suppressed, a temperature error can be suppressed and a measurement error can be reduced.

  FIG. 7 is a schematic diagram of a pressure sensor 120 according to the fourth embodiment. Although what was added to 1st Embodiment is shown in FIG. 7, 4th Embodiment can add an external component to 1st Embodiment thru | or 3rd Embodiment. In the fourth embodiment, a convex portion 124 is provided on the first concave portion 122 side of the lid 44, and the pressure introduction port 126 has a form in which the lid 44 and the convex portion 124 are communicated with each other. According to the pressure sensor 120 according to the fourth embodiment, the volume of the space formed by the first recess 122 can be further reduced, and the measurement error can be reduced by suppressing the pressure change and the temperature change.

  FIG. 8 shows a schematic diagram of pressure sensors 130 and 131 according to the fifth embodiment. FIG. 8A shows a case where it is applied to the first embodiment, and FIG. 8B shows a case where it is applied to the third embodiment. In either case, the pressure sensors 130 and 131 according to the fifth embodiment have a gap between the pressure sensor element 132a and the bottom part 134a of the first recess 134, that is, the second substrate 132 on which the pressure sensor element 132a is mounted. And a bottom portion 134a of the first recess 134, a gap is filled with a resin 136 having a low thermal conductivity. In FIG. 8A, the oscillation circuit 132b is embedded in the resin 136, and the oscillation circuit 132b can be prevented from being short-circuited. Since the volume of the internal space 134a formed by the first concave portion 134 can be further reduced by the amount embedded with the resin 136, pressure change and temperature change when the internal space 134a and the pressure measurement region are docked are suppressed. Thus, pressure sensors 130 and 131 with reduced measurement errors are obtained. In addition, since the thermal conductivity of air can vary depending on the pressure, when the pressure of air changes with the above gap, the influence of heat on the pressure sensor from the temperature compensation circuit will vary. . Therefore, as in this embodiment, by filling the gap with the resin 136 having low thermal conductivity, the heat from the temperature compensation circuit to the pressure sensor element 132a through the package is shielded, and the influence of the heat from the temperature compensation circuit is affected. In addition to being able to make it smaller, the effect of heat from the temperature compensation circuit is constant regardless of the air pressure, so fluctuations in the amount of temperature compensation by the temperature compensation circuit are suppressed, and pressure can be measured with higher accuracy. Can do.

  The fifth embodiment can be applied to the first embodiment, the third embodiment, and the fourth embodiment. Furthermore, when applied to the second embodiment, since the pressure receiving surface is directed to the bottom 14a side of the first recess 14, the bottom 14a of the first recess 14 is thick enough to prevent the pressure receiving surface from being buried in the resin 136. Is filled with the resin 136.

  FIG. 9 shows a schematic diagram of a pressure sensor 140 according to the sixth embodiment. The pressure sensor 140 according to the sixth embodiment has a configuration in which a temperature sensor element (not shown) is not disposed in the first recess 142 (in place, for example, a temperature sensor element is disposed in a pressure measurement region). As a result, the first recess 142 itself can be designed to be small. In FIG. 9, the fourth embodiment and the fifth embodiment are added to the sixth embodiment. That is, the gap is filled with the resin constituting the fifth embodiment, the design of the convex portion 124 according to the fourth embodiment is changed, and the third concave portion 146 having a shape following the outer shape of the pressure sensor element 144 is formed on the lower surface of the convex portion 124. The convex portion 124 can be provided on the lid 44 in such a manner that the pressure sensor element 144 is covered with the third concave portion 146. Thereby, the internal space 142a which the 1st recessed part 142 forms can be made quite small. Note that the sixth embodiment can be applied to the first to fifth embodiments.

It is a mimetic diagram of a pressure sensor concerning a 1st embodiment. It is a schematic diagram of the pressure sensor element which comprises the pressure sensor which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the pressure sensor which concerns on 1st Embodiment. It is a schematic diagram of the pressure sensor which concerns on 2nd Embodiment. It is a schematic diagram of the pressure sensor which concerns on 3rd Embodiment. It is a schematic diagram of the pressure sensor which concerns on 3rd Embodiment. It is a schematic diagram of the pressure sensor which concerns on 4th Embodiment. It is a schematic diagram of the pressure sensor which concerns on 5th Embodiment. It is a pressure sensor schematic diagram concerning a 6th embodiment. It is a schematic diagram of the pressure sensor which concerns on a 1st prior art. It is a schematic diagram of the pressure sensor which concerns on a 2nd prior art. It is a schematic diagram of the pressure sensor which concerns on a 3rd prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Pressure sensor, 12 ......... Package, 14 ......... First recess, 16 ......... Second recess, 18 ......... Spacer, 20 ......... Second spacer, 22 ......... First substrate 24 ......... Second substrate 26 ......... Pressure sensor element 28 ......... Element package 30 ......... Diaphragm 32 ......... Element lid 34 ......... Double tuning fork type piezoelectric vibrating piece 36 ... ...... Temperature sensor element 38 ......... Oscillation circuit 40 ......... Penetration member 42 ......... Penetration member 44 ......... Lid 46 ......... Valve 48 ......... Piping 50 ......... Pressure Introduction port 52... Temperature compensation circuit 54... Package member 56... Writing device 60... Pressure sensor 62 62 Second substrate 64 64 Connection electrode 66 ... Connecting electrode, 68 ... Pressure sensor element, 70 ... Pressure sensor, 72 ... ... Oscillator circuit 74 ... Package 76 ... Second recess 78 ... Spacer 80 ... Third substrate 82 ... Temperature compensation circuit 84 ... First substrate 86 ...... Pressure sensor element, 88 ......... Penetration member, 90 ......... Penetration member, 92 ......... Temperature sensor element, 94 ......... Second substrate, 96 ......... First recess, 100 ......... Pressure sensor , 102... Oscillation circuit 104... Temperature compensation circuit 106... First substrate 108 108 Pressure sensor element 110 Penetration member 112 Connection electrode 114 Temperature sensor element 120 ... Pressure sensor 122 ... First recess 124 ... Projection 126 ... Pressure inlet 130 ... Pressure sensor 132 ... Second substrate 134 ......... First recess, 136 ......... Resin, 140 ......... Pressure sensor, 1 2 ......... First recess, 144 ......... Pressure sensor element, 146 ......... Third recess, 201 ......... Pressure sensor, 210 ......... Case, 214 ......... Pressure introduction path, 217 ......... Communication Hole 220, ... IC chip, 221 ... Printed circuit board, 230 ... Pressure sensor element, 231 ... Diaphragm, 232 ... Insulator, 233 ... Insulator, 301 ... Insulation substrate 302 ......... Metal plate 303 ... Semiconductor element 305 ... Wiring conductor 307 ... Electrode 400 ... Pressure sensor 402 ... Base package 404 ... Lid 406 ... …… Diaphragm, 408 ……… Double tuning fork type piezoelectric vibrating piece.

Claims (10)

A package having a first recess on one side and a second recess on the other side;
A pressure sensor element disposed in the first recess and having a piezoelectric vibrating piece as a pressure sensitive element;
A temperature compensation circuit disposed in the second recess, electrically connected to the pressure sensor element, and compensating for a pressure measurement error of the pressure sensor accompanying a temperature change,
The pressure sensor, wherein the temperature compensation circuit is bonded to a spacer provided at a peripheral edge of the bottom of the second recess, and is spaced apart from the bottom.   The pressure sensor according to claim 1, wherein an oscillation circuit for oscillating the pressure sensor element is connected to the pressure sensor element while being arranged in the first recess.   The pressure sensor according to claim 1, wherein a temperature sensor element is disposed in the first recess and connected to the temperature compensation circuit.   4. The pressure sensor according to claim 1, wherein the pressure sensor element is disposed via a second spacer provided on a peripheral edge of a bottom portion of the first recess. 5.   The pressure sensor according to claim 4, wherein a pressure receiving surface of the pressure sensor element is directed to a bottom side of the first recess.   The pressure sensor according to any one of claims 1 to 5, wherein a gap between the pressure sensor element and a bottom portion of the first recess is filled with resin.   The pressure sensor according to any one of claims 1 to 6, wherein the first recess is covered with a lid, and a pressure introduction port is provided in the lid.   The pressure sensor according to claim 7, wherein an oscillation circuit for oscillating the pressure sensor element is disposed in the second recess and connected to the pressure sensor element.   The pressure sensor according to claim 7 or 8, wherein a convex portion is provided on a bottom side of the first concave portion of the lid, and the pressure introduction port is communicated with the lid and the convex portion. Forming a first recess on one surface of the package material;
Forming a second recess on the other surface;
Forming a spacer on the periphery of the bottom of the second recess,
Penetrating a penetrating member electrically conducting between the first recess and the second recess,
A pressure sensor element having a piezoelectric vibrating piece as a pressure sensitive element is disposed in the first recess and connected to the penetrating member;
Measuring a temperature dependency of a resonance frequency of the pressure sensor element from the second recess side of the penetrating member to calculate a predetermined constant of a temperature compensation circuit that compensates for a pressure measurement error of the pressure sensor element accompanying a temperature change; , Write the predetermined constant into the temperature compensation circuit,
A method of manufacturing a pressure sensor, wherein the temperature compensation circuit is connected to the penetrating member, adhered to the spacer, and spaced apart from the bottom.