JP2019060810A - Pressure sensor - Google Patents

Abstract

To compensate for temperature accurately and detect a pressure change with high accuracy.SOLUTION: Provided is a pressure sensor 1 comprising: a sensor body 3 having a communication opening 6 formed therein that communicates the inside of a cavity with the outside; a cantilever 4 that is flexurally deformed in according with a pressure difference between the inside of the cavity and the outside; a frame part 27 formed so as to enclose the periphery of the cantilever with a gap 20 provided and arranged so as to follow the opening edge of the communication opening; and a displacement detection unit, including a displacement detection resistor 46 whose resistance value changes in accordance with the flexural deformation of the cantilever, for detecting the displacement of the cantilever on the basis of a first output signal that corresponds to a resistance value change of the displacement detection resistor. The displacement detection resistor is formed in at least a lever support part 26, the frame part has formed therein a temperature detection resistor 47 having a temperature coefficient that corresponds to the temperature coefficient of the displacement detection resistor, and the displacement detection unit compensates the first output signal for temperature on the basis of the resistance value detected by the temperature detection resistor.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pressure sensor.

Conventionally, a pressure sensor is known which detects a pressure change by detecting distortion of a thin film caused by a pressure difference using a piezoresistive effect.
For example, a pressure sensor comprising a diaphragm (thin film) whose periphery is fixed by a sensor substrate, a sensor chip joined via a joint on the sensor substrate, and four strain gauges provided on the sensor chip It is known (refer patent document 1).

  The diaphragm is formed longer in the Y-axis direction than the X-axis direction in plan view, and is deformed in accordance with the pressure difference between the upper and lower sides of the diaphragm. The sensor chip is formed of a semiconductor material and is disposed above the central portion of the diaphragm. The four strain gauges are piezoresistive gauges whose resistance values change with deformation of the diaphragm, and are electrically connected to form a Wheatstone bridge circuit. Two of the four strain gauges are disposed along the X-axis direction of the diaphragm, and the remaining two strain gauges are disposed along the Y-axis direction of the diaphragm.

  According to the above conventional pressure sensor, when the diaphragm is deformed according to the pressure difference, the resistances of the four strain gauges are changed according to the deformation of the diaphragm, so that a voltage output corresponding to the pressure difference is obtained from the Wheatstone bridge circuit. Can. This makes it possible to detect a pressure change based on the voltage output. In addition, since the Wheatstone bridge circuit is configured using four strain gauges, temperature compensation of voltage output is also performed.

JP, 2016-33460, A

However, in the above-mentioned conventional pressure sensor, it is necessary to separately detect the strain (displacement) due to the deformation of the diaphragm at the respective positions of the four strain gauges. Is required.
In particular, it is necessary to arrange two strain gauges along the X axis direction of the diaphragm and to arrange the remaining two strain gauges along the Y axis direction of the diaphragm, so at least two strain gauges each There is no choice but to divide the diaphragm into the X-axis direction and the Y-axis direction. Therefore, it is necessary to arrange the strain gauges at intervals, for example, four strain gauges can not be arranged close to each other.

  Therefore, the temperature environment (the temperature environment when viewed from the viewpoint of heat transfer, for example, the heat transfer rate, the amount of transfer, etc.) differs in each place where each strain gauge is located. Therefore, for example, heat from the outside of the sensor is transmitted to the strain gauge arranged along the Y-axis direction of the diaphragm rather than the strain gauge arranged along the X-axis direction of the diaphragm, which causes a difference in temperature environment. It was easy for the inconvenience to occur. As a result, accurate temperature compensation may not be performed, and there is room for improvement.

  The present invention has been made in consideration of such circumstances, and an object thereof is to provide a pressure sensor capable of performing accurate temperature compensation and detecting pressure change with high accuracy. .

(1) A pressure sensor according to the present invention connects a sensor body in which a cavity and a communication opening communicating the inside and the outside of the cavity are formed, a lever body, the lever body, and the sensor body A cantilever supporting the lever main body in a cantilevered state, a cantilever disposed so as to cover the communication opening, and bending and deforming according to a pressure difference between the inside and the outside of the cavity; A frame formed so as to surround the periphery of the cantilever with a gap between the cantilever and the frame, and a frame portion disposed along the peripheral edge of the communication opening, and resistance according to the bending deformation of the cantilever A first Wheatstone bridge circuit including a displacement detection resistance whose value changes, and the first Wheatstone brit corresponding to a change in resistance value of the displacement detection resistance A displacement detection unit for detecting the displacement of the cantilever based on a first output signal from the circuit; the displacement detection resistor is formed at least in the lever support unit; A temperature detection resistor having a temperature coefficient corresponding to a temperature coefficient of the resistor is formed, and the displacement detection unit performs temperature compensation of the first output signal based on the resistance value detected by the temperature detection resistor.

  According to the pressure sensor according to the present invention, when the pressure outside the sensor changes, a pressure difference occurs between the inside and the outside of the cavity, and the cantilever is bent and deformed according to the pressure difference. Thereafter, as time passes, the pressure transfer medium flows from the outside of the cavity to the inside through the gap between the cantilever and the frame, so that the pressure between the inside and the outside of the cavity gradually becomes balanced. As a result, the external force acting on the cantilever due to the pressure change is gradually reduced, so the deflection of the cantilever is gradually reduced. Therefore, a pressure change can be detected by detecting the deflection amount (displacement amount) of the cantilever by the displacement detection unit.

  In particular, the cantilever bends and deforms around a lever support portion that supports the lever body in a cantilever state. Therefore, at least the displacement detection resistance formed on the lever support portion is a stress detection portion having a large contribution (contribution) to the sensitivity, and the resistance value changes corresponding to the deflection amount of the cantilever accurately. Therefore, the displacement detection unit can detect the pressure change with high sensitivity and accuracy based on the first output signal output from the first Wheatstone bridge circuit.

  By the way, at the time of the pressure change detection mentioned above, the temperature detection resistance formed in the frame changes the resistance value in accordance with the ambient temperature environment. For example, the temperature detection resistance is affected by the heat transmitted directly to the temperature detection resistance by light from the outside of the sensor, or the heat transmitted indirectly to the temperature detection resistance through the sensor main body and the frame etc. Resistance value changes. The temperature detection resistor is formed in a frame surrounding the periphery of the cantilever and disposed along the peripheral edge of the communication opening, so the temperature detection resistor is disposed at a position close to the displacement detection resistor. can do. Therefore, it is possible to make the temperature environment of the temperature detection resistor and the temperature environment of the displacement detection resistor close to the same temperature environment (similar temperature environment). Moreover, the temperature detection resistor has a temperature coefficient corresponding to the temperature coefficient of the displacement detection resistor, and the change amount of the resistance value with respect to the temperature change corresponds to the change amount of the resistance value of the displacement detection resistance with respect to the temperature change. Can. Therefore, the resistance value of the temperature detection resistor can be used as the resistance value resulting from the temperature environment of the displacement detection resistor.

  Therefore, by performing temperature compensation of the first output signal based on the resistance value detected by the temperature detection resistor, the displacement detection resistor can cancel the influence received from the ambient temperature environment, The displacement of the cantilever caused by the pressure change can be detected. As a result, accurate temperature compensation can be performed, and pressure changes can be detected with high accuracy.

(2) The cantilever and the frame portion are formed of the same semiconductor layer, and the frame portion is a projecting portion in which a portion thereof protrudes toward the inside of the communication opening than the opening peripheral portion. The temperature detection resistor may be formed on the overhang portion of the frame portion.

In this case, since the cantilever and the frame portion are formed of the same semiconductor layer, the heat conduction state (for example, the heat transfer rate, the heat transfer amount, etc.) when heat is externally transferred to the displacement detection resistor through the cantilever, for example And the heat conduction state in the case where heat is transferred from the outside to the temperature detection resistor through the frame, it is easy to make the same situation. Furthermore, since the temperature detection resistance is formed on the overhanging portion of the frame portion, the surface of the overhanging portion opposite to the surface on which the temperature detection resistance is formed is directed to the cavity side, like the cantilever. Can be exposed.
Therefore, the temperature environment of the displacement detection resistor and the temperature environment of the temperature detection resistor can be made more similar to the temperature environment, and the temperature compensation can be performed with higher accuracy.

(3) The first Wheatstone bridge circuit is a circuit further including the temperature detection resistor, and the displacement detection unit is based on the difference between the resistance value of the displacement detection resistor and the resistance value of the temperature detection resistor. The first output signal may be output from the first Wheatstone bridge circuit.

  In this case, since the first output signal is output based on the difference between the resistance value of the displacement detection resistance and the resistance value of the temperature detection resistance, even if there is a change in the temperature environment while detecting the pressure change, The first output signal can be output while canceling the change in the temperature environment. Therefore, the pressure change can be accurately detected without being affected by the change in the temperature environment, and more accurate temperature compensation can be performed.

(4) A temperature detection circuit including a second Wheatstone bridge circuit including the temperature detection resistor and outputting a second output signal corresponding to the resistance value of the temperature detection resistor, the displacement detection unit including the second detection signal The first output signal may be corrected on the basis of an output signal and temperature characteristic information on temperature dependency of the displacement detection resistor set in advance.

  In this case, the first output signal can be corrected as if pressure change detection was performed at an arbitrary temperature after grasping the actual temperature of the displacement detection resistor. Therefore, apparently, pressure change can be detected always in the same temperature environment, and pressure change can be detected accurately without being affected by the change in temperature environment. For example, even if the actual temperature environment is 10 ° C. or 30 ° C., the pressure change can be detected at a seemingly always constant 25 ° C. (temperature environment close to room temperature). Therefore, more accurate temperature compensation can be performed.

(5) The temperature detection resistor has a first resistor and a second resistor electrically separated from each other, and the first Wheatstone bridge circuit is a circuit further including the first resistor, and the second A temperature detection circuit having a second Wheatstone bridge circuit including a resistor and outputting a second output signal corresponding to the resistance value of the second resistor, wherein the displacement detection unit includes a resistance value of the displacement detection resistor; The first output signal is output from the first Wheatstone bridge circuit based on the difference from the resistance value of the first resistor, and the temperature dependency of the second output signal and the displacement detection resistor set in advance is related. The first output signal may be corrected based on the temperature characteristic information.

  In this case, since the first output signal is output based on the difference between the resistance value of the displacement detection resistor and the resistance value of the first resistor, even if there is a change in the temperature environment while detecting the pressure change, The first output signal can be output while canceling the change in the temperature environment. In addition, the first output signal can be corrected as if pressure change detection was performed at an arbitrary temperature after grasping the actual temperature of the displacement detection resistance. Therefore, apparently, pressure change can be detected always in the same temperature environment, and pressure change can be detected accurately without being affected by the change in temperature environment. From these things, very accurate temperature compensation can be performed.

  According to the present invention, accurate temperature compensation can be performed, and a high-performance pressure sensor that can detect pressure changes with high sensitivity and high sensitivity can be provided.

It is a figure showing a 1st embodiment concerning the present invention, and is a top view of a pressure sensor. It is sectional drawing of the pressure sensor along the AA shown in FIG. It is sectional drawing of the pressure sensor along the BB line shown in FIG. It is a top view of a pressure sensor for explaining detection resistance and reference resistance. It is a block diagram of the detection circuit shown in FIG. It is a figure which shows an example of the 1st output signal of the pressure sensor shown in FIG. 1, and is a figure which shows the sensor output corresponding to the relationship between external pressure and internal pressure, and the relationship. It is a figure which shows an example of operation | movement of the pressure sensor shown in FIG. 1, (A) shows the state of the pressure sensor in the state where external pressure and internal pressure are the same, (B) is external pressure higher than internal pressure. (C) is a figure which shows the state of a pressure sensor when external pressure and internal pressure are in the equilibrium state. It is a figure showing a 2nd embodiment concerning the present invention, and is a top view of a pressure sensor. It is a figure showing a 3rd embodiment concerning the present invention, and is a top view of a pressure sensor. It is a block diagram of the detection circuit and temperature detection circuit which are shown in FIG. It is a figure which shows the relationship between a 2nd output signal and the temperature of reference resistance. It is a figure showing a 4th embodiment concerning the present invention, and is a top view of a pressure sensor. It is a top view of a pressure sensor for explaining detection resistance, the 1st reference resistance, and the 2nd reference resistance. It is a block diagram of the detection circuit and temperature detection circuit which are shown in FIG. It is a figure which shows the modification of the pressure sensor which concerns on this invention, Comprising: It is a longitudinal cross-sectional view of a pressure sensor. It is a figure which shows another modification of the pressure sensor which concerns on this invention, Comprising: It is a top view of a pressure sensor.

First Embodiment
Hereinafter, a first embodiment of a pressure sensor according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the pressure sensor 1 of the present embodiment is a sensor that detects pressure changes in a predetermined frequency band, and is disposed in a space where a pressure transmission medium (for example, a gas such as air) exists Being used.

The pressure sensor 1 includes a sensor main body 3 in which a cavity 2 is formed, a cantilever 4 that can be flexibly deformed according to a pressure difference between the inside and the outside of the cavity 2, and a displacement detection unit 5 that detects displacement of the cantilever 4; Is equipped.
In the present embodiment, the side of the cantilever 4 along the thickness direction of the sensor body 3 is referred to as the upper side, and the opposite side is referred to as the lower side. Further, in plan view of the sensor main body 3, one of two directions orthogonal to each other is referred to as the front-rear direction L1, and the other direction is referred to as the left-right direction L2.

  The sensor main body 3 has a bottom wall 3a and a peripheral wall 3b, and is formed in a hollow bottomed cylindrical shape that opens upward. The internal space of the sensor main body 3 functions as the above-described cavity (air chamber) 2, and the portion opened upward functions as the communication opening 6 for communicating the inside and the outside of the cavity 2.

  The sensor main body 3 is formed in a rectangular shape in plan view in which the length along the front-rear direction L1 is longer than the length along the left-right direction L2. However, the present invention is not limited to this case, and the sensor main body 3 may be formed in, for example, a rectangular shape in plan view having a length along the lateral direction L2 longer than a length along the longitudinal direction L1. It may be formed in a square shape in plan view in which the length along the direction L1 is equal to the length along the left-right direction L2.

The sensor main body 3 is formed by integrally combining the first substrate 10 and the second substrate 11.
The first substrate 10 is, for example, an SOI substrate in which a silicon support layer 12, an insulating layer 13 such as a silicon oxide film, and a silicon active layer 14 are thermally bonded in this order from the lower side. The second substrate 11 is bonded to the silicon support layer 12 from below. Examples of the second substrate 11 include, for example, a semiconductor substrate such as silicon, but there is no particular limitation.
Examples of the method of bonding the first substrate 10 and the second substrate 11 include direct bonding methods such as diffusion bonding, normal temperature bonding and anodic bonding, and indirect bonding methods via an adhesive layer. It is not limited to

  The bottom wall 3 a of the sensor body 3 is formed of the second substrate 11. The peripheral wall 3 b of the sensor main body 3 is formed by the first substrate 10 and the second substrate 11. Further, the cantilever 4 is formed of the silicon active layer 14 in the first substrate 10.

explain in detail.
The central portion of the second substrate 11 is formed with a recess 11 a that opens upward and is recessed downward. Thus, the second substrate 11 is formed in a bottomed cylindrical shape having an annular peripheral wall 11b.
The silicon support layer 12 of the first substrate 10 is formed in an annular shape corresponding to the peripheral wall 11b of the second substrate 11, and is disposed to overlap the peripheral wall 11b. The insulating layer 13 of the first substrate 10 is formed in an annular shape corresponding to the silicon support layer 12, and is disposed to overlap the silicon support layer 12. A space formed by the recess 11 a, the silicon support layer 12, and the insulating layer 13 is a cavity 2, and an inner portion surrounded by the insulating layer 13 is a communication opening 6.

The silicon active layer 14 of the first substrate 10 is disposed on the insulating layer 13 so as to cover the communication opening 6 from above. In the silicon active layer 14, a gap 20 having a C shape in plan view, which penetrates the silicon active layer 14 in the thickness direction, is formed in a portion located inside the communication opening 6 in plan view. A portion of the silicon active layer 14 located inside the gap 20 is the cantilever 4.
The cavity 2 communicates with the outside through the gap 20. Therefore, it is possible to cause the pressure transfer medium to flow in and out of the cavity 2 through the gap 20.

The cantilever 4 has a lever main body 25 whose free end is a free end, and a lever support 26 which is integrally connected to the peripheral wall 3 b of the sensor main body 3 and supports the lever main body 25 in a cantilever state. It is arranged to cover the communication opening 6 from above.
Thus, the cantilever 4 has a cantilever structure in which the tip end side of the lever main body 25 is a free end, and the pressure difference between the inside and the outside of the cavity 2 with the lever support 26 as a center (that is, via the gap 20). It bends and deforms according to the difference in pressure due to the pressure transfer medium that can flow between the inside and the outside of the cavity 2.

The lever support portion 26 is formed such that a length (support width) along the left-right direction L2 is shorter than a length (support width) along the left-right direction L2 of the lever main body 25. In the illustrated example, the support width of the lever support portion 26 is about 1⁄4 of the support width of the lever main body 25. Thus, the cantilever 4 is configured to be easily bent and deformed about the lever support portion 26.
In the present embodiment, the direction from the lever main body 25 toward the lever support 26 along the longitudinal direction L1 is referred to as the front, and the opposite direction is referred to as the rear.

The gap 20 has a minute gap width of, for example, several hundred nm to several tens of μm, and is formed along the outer shape of the cantilever 4.
The portion of the silicon active layer 14 located outside the gap 20 is formed so as to surround the periphery of the cantilever 4 with the gap 20 between the cantilever 4 and the opening 4, and the periphery of the communication opening 6 A frame portion 27 disposed along the portion is formed.

  The frame portion 27 is formed to have a C shape in plan view corresponding to the shape of the gap 20 and is formed so that the inner peripheral edge portion protrudes toward the inside of the communication opening 6 more than the opening peripheral edge of the communication opening 6 It is done. As a result, the inner peripheral edge portion (a part of the frame portion 27) in the frame portion 27 is a projecting portion 28 projecting like a ridge toward the inside of the communication opening 6, and the communication opening 6 Partially covered.

As shown in FIG. 1, the silicon active layer 14 is formed with a groove that divides the silicon active layer 14 into a plurality of regions. In the present embodiment, four grooves, ie, the first groove 30, the second groove 31, the third groove 32, and the fourth groove 33, are formed at a depth from the upper surface of the silicon active layer 14 to the insulating layer 13.
Thus, the portion of the silicon active layer 14 excluding the cantilever 4 and the frame 27 is the connecting portion 35 integrally connected to the lever supporting portion 26 and the first base integrally connected to the connecting portion 35. It is divided into a section 36 and a second base section 37, and a third base section 38 and a fourth base section 39 integrally connected to the frame section 27.

  The first groove portion 30 is formed to extend linearly along the front-rear direction L1 so as to divide the connecting portion 35 in the left-right direction L2. In the illustrated example, the first groove 30 is formed such that the front end reaches the front side of the sensor body 3 and the rear end reaches the lever support 26. Therefore, the connecting portion 35 is divided in the left-right direction L2 by the first groove portion 30, and is divided into a first connecting portion 35a and a second connecting portion 35b.

In addition, since the first groove 30 is formed to reach the lever support 26, the lever support 26 is divided in the left-right direction L2 by the first groove 30, and the first lever support 26a and the second lever support It is divided into parts 26b. The first lever support portion 26a and the first connection portion 35a are integrally connected, and the second lever support portion 26b and the second connection portion 35b are integrally connected.
However, it is not necessary to divide the lever support portion 26 in the left-right direction L2 by the first groove portion 30, and the first connecting portion 35a and the second connecting portion 35b may be integrally connected to the lever supporting portion 26. .

The second groove portion 31 and the third groove portion 32 extend outward in the left-right direction L2 from a portion located forward of the frame 27 and located outside the lever support portion 26 in the left-right direction L2. After that, it extends backward along the frame portion 27 and further extends outward in the left-right direction L2, to reach the side surface on the left-right direction L2 side of the sensor main body 3.
Thus, the portion of the silicon active layer 14 located on the front side of the second groove 31 is made the first base 36 integrally connected to the first connecting portion 35 a, and the third groove of the silicon active layer 14 is formed. A portion located on the front side of 32 is a second base portion 37 integrally connected to the second connecting portion 35b.

  The first base portion 36 and the second base portion 37 are disposed apart from each other in the left-right direction L2 via the first groove portion 30. Further, the frame portion 27 and the first connecting portion 35 a are disposed apart from each other in the left-right direction L 2 via the second groove portion 31, and the frame portion 27 and the second connecting portion 35 b are laterally They are disposed apart from each other in the direction L2.

The fourth groove 33 is disposed rearward of the frame 27 and is formed to reach the side surface on the rear side of the sensor main body 3. In the illustrated example, the fourth groove 33 is formed in a rectangular shape in plan view longer in the left-right direction L2 than in the front-rear direction L1.
Thus, the portion of the silicon active layer 14 located on the rear side of the first base portion 36 serves as the third base portion 38 integrally connected to the frame portion 27. Further, a portion of the silicon active layer 14 located on the rear side of the second base portion 37 is a fourth base portion 39 integrally connected to the frame portion 27.
The third base portion 38 and the fourth base portion 39 are disposed separately from the first base portion 36 and the second base portion 37 via the first groove portion 30 and the second groove portion 31, respectively. Further, the third base portion 38 and the fourth base portion 39 are disposed apart from each other in the left-right direction L2 via the fourth groove portion 33.

  The cantilever 4, the frame portion 27, the connection portion 35, the first base portion 36, the second base portion 37, the third base portion 38 and the fourth base portion 39 described above are formed from the silicon active layer 14 which is the same semiconductor layer It is done.

The upper surfaces of the first base portion 36, the second base portion 37, the third base portion 38, and the fourth base portion 39 are made of a conductive material (for example, AU or the like) having a smaller electrical resistivity than the piezoresistive layer 45 described later. An external electrode is formed corresponding to the shape of each base.
Specifically, the first external electrode 40 is formed on the entire top surface of the first base portion 36. A second external electrode 41 is formed on the entire top surface of the second base portion 37. A third external electrode 42 is formed on the entire top surface of the third base portion 38. A fourth external electrode 43 is formed on the entire top surface of the fourth base portion 39.

  In addition, it is preferable to prevent the electrical contact with the exterior by covering the upper surface of the 1st exterior electrode 40-the 4th exterior electrode 43 as a protective film not shown. The first to fourth external electrodes 40 to 43 are electrically insulated from one another.

  A piezoresistive layer 45 is formed on the entire surface of the silicon active layer 14 as the cantilever 4, the frame portion 27 and the connecting portion 35. The piezoresistive layer 45 is formed, for example, by doping a doping agent (impurity) such as phosphorus by various methods such as an ion implantation method or a diffusion method.

As shown in FIG. 4, a portion (the lever support 26 and the lever main body 25 are formed in the piezoresistive layer 45 in which the connecting portion 35 (the first connecting portion 35 a and the second connecting portion 35 b) and the cantilever 4 are formed. Portion functions as a detection resistance (displacement detection resistance) 46 whose resistance value changes according to the bending deformation of the cantilever 4.
The detection resistor 46 is electrically connected to the first external electrode 40 and the second external electrode 41, respectively. Thereby, when a voltage is applied between the first external electrode 40 and the second external electrode 41, a current resulting from the voltage application is transmitted from the first external electrode 40 via the detection resistor 46 to the second external electrode 41. Flow to

The portion of the piezoresistive layer 45 in which the frame portion 27 including the overhanging portion 28 is formed functions as a reference resistance (temperature detection resistance) 47 having a temperature coefficient corresponding to the temperature coefficient of the detection resistance 46. The temperature coefficient corresponding to the temperature coefficient of the detection resistor 46 is, for example, a coefficient equivalent to the temperature coefficient of the detection resistor 46 (coefficient identical or similar) or a ratio determined in advance to the temperature coefficient of the detection resistor 46 Includes related coefficients etc. Thus, the reference resistor 47 has a temperature characteristic corresponding to the detection resistor 46.
The reference resistor 47 is electrically connected to the third external electrode 42 and the fourth external electrode 43, respectively. Thereby, when a voltage is applied between the third external electrode 42 and the fourth external electrode 43, a current resulting from this voltage application is transmitted from the third external electrode 42 via the reference resistor 47 to the fourth external electrode 43. Flow to

The displacement detection unit 5 includes a detection circuit 50 having a bridge circuit (first Wheatstone bridge circuit) 51 including the detection resistance 46 shown in FIG. 5, and the first detection from the bridge circuit 51 corresponding to the resistance value change of the detection resistance 46. The displacement of the cantilever 4 is detected based on the output signal V1. At this time, the displacement detection unit 5 performs temperature compensation of the first output signal V1 based on the resistance value detected by the reference resistor 47.
Specifically, the bridge circuit 51 is a circuit further including a reference resistor 47 in addition to the detection resistor 46, and the displacement detector 5 is based on the difference between the resistance value of the detection resistor 46 and the resistance value of the reference resistor 47. Temperature compensation is performed by outputting the first output signal V1 from the bridge circuit 51.

It will be described in detail.
As shown in FIG. 5, the detection circuit 50 includes a bridge circuit 51, a reference voltage generation circuit 52 that applies a predetermined reference voltage Vcc to the bridge circuit 51, and a differential amplifier circuit 53. The bridge circuit 51 has a branch side in which the detection resistor 46 and the reference resistor 47 are connected in series, and a branch side in which the first fixed resistor 54 and the second fixed resistor 55 are connected in series. Connected in parallel.

  The detection resistor 46 has a first end connected to the supply line of the reference voltage Vcc and a second end connected to the node N1. The reference resistor 47 has a first end connected to the node N1, and a second end connected to the power supply line GND. The first fixed resistor 54 has a first end connected to the supply line of the reference voltage Vcc, and a second end connected to the node N2. The second fixed resistor 55 has a first end connected to the node N2, and a second end connected to the power supply line GND. The first fixed resistor 54 and the second fixed resistor 55 are external resistors provided outside the sensor body 3.

  The differential amplifier circuit 53 is, for example, a measurement amplifier, amplifies the potential difference between the node N1 and the node N2 at a predetermined amplification factor, and outputs the amplified signal as a first output signal V1. In the differential amplifier circuit 53, the inverting input terminal (-terminal) is connected to the node N1, and the non-inverting input terminal (+ terminal) is connected to the node N2. The node N1 has a voltage corresponding to the difference between the resistance value of the detection resistor 46 and the resistance value of the reference resistor 47.

  The first external electrode 40 functions as the first end of the detection resistor 46, and the supply line of the reference voltage Vcc is connected. The second external electrode 41 functions as the second end of the detection resistor 46, and the inverting input terminal (-terminal) of the differential amplifier circuit 53 is connected via the node N1. The third external electrode 42 functions as a first end of the reference resistor 47, and the inverting input terminal (-terminal) of the differential amplifier circuit 53 is connected via the node N1. The fourth external electrode 43 functions as the second end of the reference resistor 47, and the power supply line GND is connected.

(Function of pressure sensor)
Next, the case where a pressure change is detected using the pressure sensor 1 configured as described above will be described.

  As shown in period A shown in FIG. 6A, the pressure outside the cavity 2 (hereinafter referred to as the outside pressure Pout) and the pressure inside the cavity 2 (hereinafter referred to as the inside pressure Pin) are equal, and the difference When the pressure (ΔP) is zero, as shown in FIG. 7A, the cantilever 4 is not bent and deformed. Thereby, the first output signal V1 output from the detection circuit 50 is a predetermined value (for example, zero).

  Then, as in period B after time t1 shown in FIG. 6A, for example, when the outside pressure Pout rises stepwise, the inside pressure Pin does not change rapidly so as to follow the change in the outside pressure Pout, A differential pressure (ΔP) is generated between the outside and the inside of the cavity 2. As a result, as shown in FIG. 7B, the cantilever 4 is bent and deformed toward the inside of the cavity 2. Then, a stress acts on the detection resistor 46 according to the bending deformation of the cantilever 4, thereby changing the resistance value of the detection resistor 46, so that the first output signal V1 is of the cantilever 4 as shown in FIG. It increases according to the amount of deflection (displacement).

  After the increase of the outside pressure Pout, the pressure transfer medium flows from the outside to the inside of the cavity 2 through the gap 20. Therefore, as shown in period C after time t2 shown in FIG. 6 (A), the internal pressure Pin rises with a response slower than the external pressure Pout and with a slower response than the fluctuation of the external pressure Pout as time passes. . As a result, since the internal pressure Pin gradually approaches the external pressure Pout, the pressure between the outside and the inside of the cavity 2 begins to be in equilibrium, and the deflection of the cantilever 4 gradually decreases. As a result, as in period C shown in FIG. 6B, the first output signal V1 gradually decreases.

  Then, as in period D after time t3 shown in FIG. 6A, when the internal pressure Pin becomes equal to the external pressure Pout, the bending deformation of the cantilever 4 is eliminated as shown in FIG. Return to the state. As a result, as shown in FIG. 6B, the first output signal V1 also returns to the same value as the initial state of the period A.

  As described above, according to the pressure sensor 1 of the present embodiment, the displacement detection unit 5 detects a pressure change by monitoring the change of the first output signal V1 based on the deflection amount (displacement amount) of the cantilever 4 can do.

In particular, the cantilever 4 is bent and deformed about the lever supporting portion 26 which supports the lever main body 25 in a cantilever state. Therefore, the detection resistance 46 mainly formed on the lever support portion 26 is a stress detection portion where the degree of contribution (the degree of contribution) to the sensitivity is large, and the resistance value changes corresponding to the deflection amount of the cantilever 4 exactly. . Therefore, based on the first output signal V1 output from the bridge circuit 51, the pressure change can be detected with high accuracy and sensitivity.
In addition, since the cantilever 4 can be formed by the semiconductor process technology using the silicon active layer 14 of the first substrate 10 which is the SOI substrate, it is easy to reduce the thickness (for example, several tens to several hundreds of nm). Therefore, a minute pressure change can be detected with high accuracy.

  By the way, at the time of the detection of the pressure change mentioned above, the resistance value of the reference resistor 47 formed in the frame 27 changes in accordance with the ambient temperature environment. For example, heat directly transmitted to the reference resistor 47 by light (visible light, infrared light, etc.) from the outside of the sensor, or influence of heat indirectly transmitted to the reference resistor 47 through the sensor body 3 and the frame 27 etc. In response, the reference resistance 47 changes its resistance value. The reference resistor 47 is formed in the frame 27 (including the overhang 28) disposed so as to surround the cantilever 4 and along the opening peripheral edge of the communication opening 6. It can be placed in close proximity to the

  Therefore, the temperature environment of the reference resistor 47 and the temperature environment of the detection resistor 46 can be brought close to the same temperature environment (similar temperature environment). Moreover, the reference resistor 47 has a temperature coefficient corresponding to the temperature coefficient of the detection resistor 46, and the amount of change in resistance with respect to temperature change is made to correspond to the amount of change in resistance of the detection resistor 46 with temperature change. Can. Therefore, the resistance value of the reference resistor 47 can be used as the resistance value resulting from the temperature environment of the detection resistor 46.

Therefore, the displacement detection unit 5 performs temperature compensation of the first output signal V1 based on the resistance value detected by the reference resistor 47, thereby canceling the influence of the detection resistor 46 from the ambient temperature environment. it can.
Specifically, as shown in FIG. 5, the bridge circuit 51 is a circuit including the detection resistor 46 and the reference resistor 47, and the node N1 in the circuit is the resistance value of the detection resistor 46 and the resistance value of the reference resistor 47. Voltage according to the difference between Therefore, since the change in node N1 appears as a potential difference between nodes N1 and N2, the influence of the temperature environment is canceled based on the first output signal V1 output from differential amplifier circuit 53. The change of the outside air pressure Pout can be detected accurately.

  That is, since the bridge circuit 51 outputs the first output signal V1 based on the difference between the resistance value of the detection resistor 46 and the resistance value of the reference resistor 47, even if there is a change in the temperature environment while detecting the pressure change. The first output signal V1 can be output while canceling the change in the temperature environment. Therefore, the pressure change can be accurately detected without being affected by the change in the temperature environment of the detection resistor 46.

  From the above, according to the pressure sensor 1 of the present embodiment, accurate temperature compensation can be performed, pressure change detection can be performed with high sensitivity and high accuracy, and a high performance sensor can be obtained. it can.

Furthermore, since the cantilever 4 and the frame portion 27 are formed of the same semiconductor layer, ie, the silicon active layer 14, the heat conduction state (eg, heat transfer rate) when heat is externally transmitted to the detection resistor 46 through the cantilever 4, for example And the amount of heat transfer) and the heat conduction state in the case where the heat is transmitted from the outside to the reference resistor 47 through the frame portion 27 can easily be made the same state.
In addition to that, as shown in FIG. 4, the reference resistance 47 is formed in the frame portion 27 which is a part of the projecting portion 28. It is possible to expose the surface (lower surface) opposite to the surface (upper surface) on which the is formed toward the cavity 2 side. Therefore, the temperature environment of the detection resistor 46 and the temperature environment of the reference resistor 47 can be made more similar to each other. Therefore, temperature compensation can be performed with higher accuracy.

In addition, since the pressure sensor 1 of this embodiment can be successful in each effect mentioned above, it is possible to apply to the following various uses, for example. In particular, since temperature compensation can be performed, the present invention can be applied to the following various applications in a state insusceptible to the temperature environment.
For example, it is possible to apply to a navigation device for cars. In this case, since the pressure difference based on the height difference can be detected using, for example, the pressure sensor 1, the elevated road and the road under the elevated road can be accurately determined and reflected in the navigation result.
Moreover, it is also possible to apply to a portable navigation device. In this case, since the pressure difference based on the height difference can be detected using, for example, the pressure sensor 1, it can be accurately determined on which floor in the building the user is located and reflected in the navigation result.
Furthermore, since it is possible to detect an atmospheric pressure change in a room, it is also possible to apply to, for example, a security device for a building or an automobile. In particular, even pressure fluctuations in the frequency band of 1 Hz or less can be detected with high sensitivity. Therefore, even pressure fluctuations based on the opening and closing of doors and sliding doors can be detected. Preferred.

Second Embodiment
Next, a second embodiment according to the present invention will be described with reference to the drawings. In the second embodiment, the same parts as those in the first embodiment are indicated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 8, in the pressure sensor 60 of the present embodiment, a part of the third external electrode 42 and the fourth external electrode 43 wrap around to the front side than the frame portion 27, and to the front side of the frame portion 27. The second groove 31, the third groove 32, and the fourth groove 33 are formed to be connected to the positioned portion.
As a result, the entire piezoresistive layer 45 formed in the frame portion 27 can be used as the reference resistor 47, and the position of the reference resistor 47 is mainly detected in the lever support portion 26 of the cantilever 4. It can be made closer to 46.

  Therefore, according to the pressure sensor 60 of the present embodiment, the temperature environment of the detection resistor 46 and the temperature environment of the reference resistor 47 can be made more similar to the temperature environment, and further highly accurate temperature compensation can be performed. .

Third Embodiment
Next, a third embodiment according to the present invention will be described with reference to the drawings. In the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof is omitted.
In the first embodiment, the detection resistor 46 and the reference resistor 47 are incorporated in the bridge circuit 51. However, in the present embodiment, the reference resistor 47 is incorporated in the bridge circuit other than the detection resistor 46 and the reference resistor 47 is provided. It functions as a so-called temperature sensor.

  As shown in FIGS. 9 and 10, the pressure sensor 70 of the present embodiment has a bridge circuit (second Wheatstone bridge circuit) 72 including a reference resistor 47, and a second output corresponding to the resistance value of the reference resistor 47. It further includes a temperature detection circuit 71 that outputs a signal V2.

The bridge circuit 51 of the present embodiment includes a third fixed resistor 73 in place of the reference resistor 47.
That is, in the bridge circuit 51, a reference voltage generating circuit is a branch side in which the detection resistor 46 and the third fixed resistor 73 are connected in series, and a branch side in which the first fixed resistor 54 and the second fixed resistor 55 are connected in series. It is connected in parallel to 52. The third fixed resistor 73 is an external resistor provided outside the sensor body 3 like the first fixed resistor 54 and the second fixed resistor 55, and the first end is connected to the node N1, Two ends are connected to the power supply line GND.

  The temperature detection circuit 71 includes a bridge circuit 72 and a differential amplifier circuit 74. In the bridge circuit 72, a branch side in which the reference resistor 47 and the fourth fixed resistor 75 are connected in series and a branch side in which the fifth fixed resistor 76 and the sixth fixed resistor 77 are connected in series are connected in parallel. .

  The first end of the reference resistor 47 is connected to the supply line of the reference voltage Vcc, and the second end is connected to the node N3. The fourth fixed resistor 75 has a first end connected to the node N3 and a second end connected to the power supply line GND. The fifth fixed resistor 76 has a first end connected to the supply line of the reference voltage Vcc, and a second end connected to the node N4. The sixth fixed resistor 77 has a first end connected to the node N4, and a second end connected to the power supply line GND. The fourth fixed resistor 75, the fifth fixed resistor 76 and the sixth fixed resistor 77 are external resistors provided outside the sensor body 3.

  Similar to the differential amplifier circuit 53 in the detection circuit 50, the differential amplifier circuit 74 is, for example, a measurement amplifier, and amplifies the potential difference between the node N3 and the node N4 by a predetermined amplification factor to generate a second output signal. Output as V2. In the differential amplifier circuit 74, the inverting input terminal (-terminal) is connected to the node N3, and the non-inverting input terminal (+ terminal) is connected to the node N4.

  In the present embodiment, the first external electrode 40 functions as the first end of the detection resistor 46, and the supply line of the reference voltage Vcc is connected. The second external electrode 41 functions as the second end of the detection resistor 46, and the inverting input terminal (-terminal) of the differential amplifier circuit 53 is connected via the node N1. The third external electrode 42 functions as the first end of the reference resistor 47, and the supply line of the reference voltage Vcc is connected. The fourth external electrode 43 functions as the second end of the reference resistor 47, and the inverting input terminal (-terminal) of the differential amplifier circuit 74 is connected via the node N3.

  The displacement detection unit 5 includes a temperature characteristic storage unit 78 that stores temperature characteristic information on the temperature dependency of the reference resistor 47. As shown in FIG. 11, the temperature characteristic storage section 78 stores the above-mentioned temperature characteristic information indicating the relationship between the second output signal V2 and the temperature Ttmp of the reference resistor 47. The displacement detection unit 5 outputs the first output signal from the bridge circuit 51 based on the second output signal V2 output from the bridge circuit 72 and the temperature characteristic information stored (set) in advance in the temperature characteristic storage unit 78. The output signal V1 is corrected.

(Function of pressure sensor)
According to the pressure sensor 70 of the present embodiment configured as described above, since the temperature detection circuit 71 is provided, it is possible to grasp the actual temperature of the detection resistor 46 based on the second output signal V2. it can. In addition, the displacement detection unit 5 corrects the first output signal V1 output from the bridge circuit 51 based on the second output signal V2 and the temperature characteristic information stored in advance in the temperature characteristic storage unit 78. The first output signal V1 can be corrected as if the pressure change was detected at the temperature of.

  Therefore, apparently, pressure change can be detected always in the same temperature environment, and pressure change can be detected accurately without being influenced by the change in temperature environment. For example, even if the actual temperature environment of the detection resistor 46 is 10 ° C. or 30 ° C., the pressure change can be detected at a seemingly constant 25 ° C. (temperature environment at room temperature). As a result, more accurate temperature compensation can be performed.

Fourth Embodiment
Next, a fourth embodiment according to the present invention will be described with reference to the drawings. In the fourth embodiment, the same parts as those in the first embodiment and the third embodiment are designated by the same reference numerals and the description thereof will be omitted.

  In the first embodiment, the bridge circuit 51 includes the detection resistor 46 and the reference resistor 47. However, in the present embodiment, the reference resistor 47 includes two resistors (a first reference resistor 81 and a second reference resistor 82). , The detection resistor 46 and the first reference resistor 81 are incorporated in the bridge circuit 51, the second reference resistor 82 is incorporated in the bridge circuit 72 different from the detection resistor 46, and the second reference resistor 82 is a so-called temperature sensor. It is functioning.

As shown in FIG. 12, in the pressure sensor 80 according to the present embodiment, in addition to the first groove 30 to the fourth groove 33, the fifth groove 83, the sixth groove 84 and the seventh groove 89 are added to the silicon active layer 14. It is formed to a depth reaching the insulating layer 13 from the upper surface of the silicon active layer 14.
The fifth base portion 85 and the sixth base portion 86 integrally connected to the frame portion 27 in the silicon active layer 14 excluding the cantilever 4 and the frame portion 27 by the fifth groove portion 83 and the sixth groove portion 84. Is further formed.

The second groove portion 31 and the third groove portion 32 in the present embodiment are located forward of the frame 27 and outside the left-right direction L2 relative to the lever support 26 in the left-right direction L2. It extends linearly and reaches the side surface of the sensor main body 3 in the left-right direction L2.
The fifth groove portion 83 and the sixth groove portion 84 are disposed on the front side of the third base portion 38 and the fourth base portion 39, and from the portion located on the outer side in the left-right direction L2 than the frame 27, the outer side in the left-right direction L2. Extending straight to the side surface of the sensor body 3 in the left-right direction L2. As a result, the portion of the silicon active layer 14 located between the second groove 31 and the fifth groove 83 is made the fifth base 85 integrally connected to the frame 27, and the silicon active layer 14 has the fifth base 85. A portion located between the third groove portion 32 and the sixth groove portion 84 is a sixth base portion 86 integrally connected to the frame portion 27.

  On the top surfaces of the fifth base portion 85 and the sixth base portion 86, fifth external electrodes 87 and a sixth external made of a conductive material (for example, AU or the like) whose electric resistivity is lower than that of the piezoresistive layer 45 over the entire surface. Electrodes 88 are respectively formed.

The seventh groove 89 is formed to extend along the front-rear direction L1 so as to divide the portion of the frame 27 located on the rear side in the left-right direction L2. Thus, the reference resistor 47 is electrically separated in the left-right direction L2 by the seventh groove 89.
That is, as shown in FIG. 13, the reference resistor 47 is a first reference resistor (first resistor) 81 located on the third external electrode 42 and the fifth external electrode 87 side, a fourth external electrode 43 and a sixth external It divides into the 2nd reference resistance (2nd resistance) 82 located in the electrode 88 side.

The first reference resistor 81 is electrically connected to the third external electrode 42 and the fifth external electrode 87, respectively. Thus, when a voltage is applied between the third external electrode 42 and the fifth external electrode 87, the current resulting from this voltage application is transmitted from the third external electrode 42 to the fifth external via the first reference resistor 81. It flows to the electrode 87.
The second reference resistor 82 is electrically connected to the fourth external electrode 43 and the sixth external electrode 88, respectively. Thus, when a voltage is applied between the fourth external electrode 43 and the sixth external electrode 88, the current resulting from this voltage application is transmitted from the fourth external electrode 43 to the sixth external via the second reference resistor 82. It flows to the electrode 88.

As shown in FIG. 14, the bridge circuit 51 of the present embodiment is a circuit including a detection resistor 46 and a first reference resistor 81, and the displacement detection unit 5 has a resistance value of the detection resistor 46 and a resistance of the first reference resistor 81. The first output signal V1 is output from the bridge circuit 51 based on the difference from the value.
In the bridge circuit 51, the reference voltage generation circuit 52 includes a branch side in which the detection resistor 46 and the first reference resistor 81 are connected in series, and a branch side in which the first fixed resistor 54 and the second fixed resistor 55 are connected in series. They are connected in parallel to each other.
A first end of the first reference resistor 81 is connected to the node N1, and a second end is connected to the power supply line GND.

  Furthermore, in the bridge circuit 72 of the present embodiment, a branch side in which the second reference resistor 82 and the fourth fixed resistor 75 are connected in series, and a branch side in which the fifth fixed resistor 76 and the sixth fixed resistor 77 are connected in series; Are connected in parallel. The second reference resistor 82 has a first end connected to the supply line of the reference voltage Vcc, and a second end connected to the node N3.

  In the present embodiment, the first external electrode 40 functions as the first end of the detection resistor 46, and the supply line of the reference voltage Vcc is connected. The second external electrode 41 functions as the second end of the detection resistor 46, and the inverting input terminal (-terminal) of the differential amplifier circuit 53 is connected via the node N1. The third external electrode 42 functions as the first end of the first reference resistor 81, and the inverting input terminal (-terminal) of the differential amplifier circuit 53 is connected via the node N1. The fifth external electrode 87 functions as the second end of the first reference resistor 81 and is connected to the power supply line GND. The fourth external electrode 43 functions as the first end of the second reference resistor 82, and the supply line of the reference voltage Vcc is connected. The sixth external electrode 88 functions as the second end of the second reference resistor 82, and the inverting input terminal (-terminal) of the differential amplifier circuit 74 is connected via the node N3.

  The displacement detection unit 5 includes the temperature characteristic storage unit 78 as in the third embodiment, and is based on the second output signal V2 output from the bridge circuit 72 and the temperature characteristic information stored in advance in the temperature characteristic storage unit 78. Thus, the first output signal V1 output from the bridge circuit 51 is corrected.

(Function of pressure sensor)
According to the pressure sensor 80 of this embodiment configured as described above, as in the first embodiment, the bridge circuit 51 is based on the difference between the resistance value of the detection resistor 46 and the resistance value of the first reference resistor 81. Since the first output signal V1 is output, even if there is a change in the temperature environment during the pressure change detection, the first output signal V1 can be output in a state in which the change in the temperature environment is canceled.

In addition to that, as in the third embodiment, the displacement detection unit 5 outputs the first output from the bridge circuit 51 based on the second output signal V2 and the temperature characteristic information stored in advance in the temperature characteristic storage unit 78. Since the output signal V1 is corrected, it is possible to correct the first output signal V1 as if the pressure change was detected at an arbitrary temperature. Therefore, apparently, pressure change can be detected always in the same temperature environment, and pressure change can be detected accurately without being influenced by the change in temperature environment.
From these things, according to the pressure sensor 80 of the present embodiment, it is possible to perform temperature compensation with high accuracy.

  While the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiment can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. The embodiments and the modifications thereof include, for example, those which can be easily conceived by those skilled in the art, substantially the same ones, and equivalent ranges.

  For example, in each of the above embodiments, the sensor main body 3 is configured by combining the first substrate 10 and the second substrate 11 integrally, but the present invention is not limited to this case.

For example, as shown in FIG. 15, a pressure sensor in which the sensor main body 3 is constituted by the first substrate 10 which is an SOI substrate, a circuit substrate 91, and a top cylindrical lid member 92 formed of a heat insulating material or the like. It does not matter as 90.
The first substrate 10 is bonded onto the circuit board 91. The circuit board 91 is formed with a through hole 91 a penetrating the circuit board 91 in the thickness direction and communicating with the communication opening 6 of the first board 10. The lid member 92 is closely bonded, for example, on the circuit board 91 so as to cover the first substrate 10 from above. Thereby, the inside of the lid member 92 functions as the cavity 2.
Even in the case of the pressure sensor 90 configured in this way, the cantilever 4 can be bent and deformed in accordance with the pressure difference between the inside and the outside of the cavity 2. Therefore, the same effects as those of the above-described embodiments Can be effective.

Furthermore, in each of the above embodiments, the frame portion 27 is formed to include the projecting portion 28. For example, as shown in FIG. 16, along the opening peripheral edge of the communication opening 6 and inside the communication opening 6 as shown in FIG. The pressure sensor 100 may have the frame portion 27 so as not to protrude (do not protrude).
Even in this case, since the portion of the piezoresistive layer 45 formed in the frame portion 27 can be used as the reference resistor 47, temperature compensation can be performed as in the embodiments.
However, in the case where the frame portion 27 is formed to have the overhanging portion 28 as described in each of the above-described embodiments, the lower surface of the overhanging portion 28 can be exposed toward the cavity 2 side. The temperature environment of the resistor 47 can be made more similar to the temperature environment of the detection resistor 46 formed on the cantilever 4 exposed on the lower surface side toward the cavity 2 side. Therefore, it is easy to perform temperature compensation with higher accuracy, which is preferable.

1, 60, 70, 80, 90, 100 ... pressure sensor 2 ... cavity 3 ... sensor main body 4 ... cantilever 5 ... displacement detection unit 6 ... communication opening 14 ... silicon active layer (semiconductor layer)
20 ... gap 25 ... lever main body 26 ... lever support part 27 ... frame part 28 ... overhang part 46 ... detection resistance (displacement detection resistance)
47 ... Reference resistance (temperature detection resistance)
51 ... bridge circuit (first Wheatstone bridge circuit)
71 ... temperature detection circuit 72 ... bridge circuit (second Wheatstone bridge circuit)
81 ... 1st reference resistance (1st resistance)
82 ... 2nd reference resistance (2nd resistance)

Claims (5)

A sensor body in which a cavity and a communication opening communicating the inside and the outside of the cavity are formed;
A lever main body, a lever supporting portion connecting the lever main body and the sensor main body and supporting the lever main body in a cantilever state, and arranged to cover the communication opening, and inside the cavity Cantilevers that deform in response to the pressure difference between the
A frame portion formed so as to surround the periphery of the cantilever in a state where a gap is opened between the cantilever and the frame portion, which is disposed along the peripheral edge of the communication opening;
A first output signal from the first Wheatstone bridge circuit having a first Wheatstone bridge circuit including a displacement detection resistor whose resistance value changes according to a bending deformation of the cantilever, and corresponding to a change in the resistance value of the displacement detection resistor A displacement detection unit that detects the displacement of the cantilever based on
The displacement detection resistance is formed at least on the lever support portion,
The frame portion is formed with a temperature detection resistor having a temperature coefficient corresponding to the temperature coefficient of the displacement detection resistor,
The displacement sensor performs temperature compensation of the first output signal based on a resistance value detected by the temperature detection resistor. In the pressure sensor according to claim 1,
The cantilever and the frame portion are formed of the same semiconductor layer,
The frame portion is a projecting portion in which a portion thereof protrudes toward the inside of the communication opening than the opening peripheral portion,
The pressure sensor, wherein the temperature detection resistor is formed on the overhang portion of the frame portion. In the pressure sensor according to claim 1 or 2,
The first Wheatstone bridge circuit is a circuit further including the temperature detection resistor,
The displacement sensor outputs the first output signal from the first Wheatstone bridge circuit based on the difference between the resistance value of the displacement detection resistor and the resistance value of the temperature detection resistor. In the pressure sensor according to claim 1 or 2,
A temperature detection circuit having a second Wheatstone bridge circuit including the temperature detection resistor, and outputting a second output signal corresponding to the resistance value of the temperature detection resistor;
The displacement sensor corrects the first output signal on the basis of the second output signal and temperature characteristic information on temperature dependency of the displacement detection resistor set in advance. In the pressure sensor according to claim 1 or 2,
The temperature detection resistor has a first resistor and a second resistor electrically separated from each other,
The first Wheatstone bridge circuit is a circuit further including the first resistor,
A temperature detection circuit having a second Wheatstone bridge circuit including the second resistor and outputting a second output signal corresponding to a resistance value of the second resistor;
The displacement detection unit outputs the first output signal from the first Wheatstone bridge circuit based on the difference between the resistance value of the displacement detection resistor and the resistance value of the first resistor, and the second output signal. And a pressure sensor that corrects the first output signal based on temperature characteristic information on temperature dependency of the displacement detection resistor set in advance.

Images