阅读说明：本技术 压力传感器 (Pressure sensor ) 是由 泷本和哉 于 2018-12-27 设计创作，主要内容包括：本发明的目的在于,在使用压阻效应方式之类的半导体压力传感器片(126)的压力传感器(100)中,通过管理零件的形状、加工精度能得到均匀的粘接剂层(125A)的厚度,减少因现有的温度变化所引起的半导体压力传感器片(126)、支撑部件、粘接剂等的线膨胀系数的差异而产生的半导体压力传感器片(126)的形变,从而能提高传感器输出的精度。本发明的压力传感器(100)中,在支柱(125)的与半导体压力传感器片(126)面对面的面,形成有作为形成于中央的平坦的突起部的槽内凸部(125a)和作为与槽内凸部(125a)之间隔开槽(125b)地形成于支柱(125)的周围的圆环形状的突起部的传感器片支撑部(125c)。粘接剂层(125A)的厚度根据槽内凸部(125a)与抵接于半导体压力传感器片(126)的传感器片支撑部(125c)之间的间隙Δg来决定。(The purpose of the present invention is to provide a pressure sensor (100) using a semiconductor pressure sensor sheet (126) of piezoresistive effect type or the like, wherein the shape of parts and the processing accuracy are managed to obtain a uniform thickness of an adhesive layer (125A), thereby reducing the deformation of the semiconductor pressure sensor sheet (126) caused by the difference in linear expansion coefficients of the semiconductor pressure sensor sheet (126), a support member, an adhesive, and the like due to the conventional temperature change, and improving the accuracy of sensor output. In the pressure sensor (100), an in-groove convex portion (125a) as a flat convex portion formed at the center and a sensor piece supporting portion (125c) as an annular convex portion formed around a pillar (125) with a groove (125b) at an interval from the in-groove convex portion (125a) are formed on the surface of the pillar (125) facing a semiconductor pressure sensor piece (126). The thickness of the adhesive layer (125A) is determined by the gap delta g between the in-groove convex part (125A) and a sensor sheet support part (125c) in contact with the semiconductor pressure sensor sheet (126).)

1. A pressure sensor is provided with:

a semiconductor pressure sensor sheet having a diaphragm portion therein;

a support member that supports the semiconductor pressure sensor sheet; and

an adhesive layer for adhering and fixing the semiconductor pressure sensor sheet to the support member,

the above-mentioned pressure sensor is characterized in that,

the support member is provided with a projection portion which is not in contact with the semiconductor pressure sensor chip and a sensor chip support portion which is in contact with the semiconductor pressure sensor chip,

the adhesive layer is formed on the protruding portion,

the thickness of the adhesive layer is determined by the gap between the protrusion and the sensor sheet support portion.

2. The pressure sensor of claim 1,

the sensor sheet support portion is formed around the protrusion portion via a groove formed between the protrusion portion and the sensor sheet support portion.

3. The pressure sensor of claim 1,

the bonding region of the protrusion formed on the support member is located inside a projection of the diaphragm portion of the semiconductor pressure sensor sheet with respect to the support member.

4. The pressure sensor of claim 1,

the support member is a metal pillar fixed to the outside in an insulated manner.

5. The pressure sensor of claim 1,

the support member is a base constituting a casing of the pressure sensor.

6. The pressure sensor of claim 5,

the base is made of conductive material.

7. The pressure sensor of claim 5,

the base is made of an insulating material.

8. The pressure sensor of claim 1,

the support member further includes a mounting substrate disposed in the liquid sealing chamber and supporting the semiconductor pressure sensor chip.

9. The pressure sensor of claim 8,

the mounting substrate is formed of an insulating material.

10. The pressure sensor of claim 9,

a conductive material is bonded to one surface of the mounting substrate on which the semiconductor pressure sensor chip is fixed.

11. The pressure sensor of claim 1,

a protrusion is formed on the support member and around the sensor sheet support portion in contact with the semiconductor pressure sensor sheet, and the adhesive layer is formed on the protrusion.

Technical Field

The present invention relates to a pressure sensor, and more particularly, to a pressure sensor using a semiconductor pressure sensor sheet as in the piezoresistive effect type.

Background

Conventionally, as a pressure sensor for detecting a pressure of a fluid, for example, a pressure sensor using a semiconductor pressure sensor chip such as a piezoresistive effect type, another electrostatic capacitance type detection type, or a silicon resonance type is known.

Among the most common piezoresistive semiconductor pressure sensor sheets, a sheet portion is formed of a material having a piezoresistive effect (for example, single crystal silicon), a plurality of semiconductor strain gauges are formed on the surface of the sheet portion, and the semiconductor strain gauges are bridged to form a bridge circuit. Then, the diaphragm portion is deformed in accordance with a change in the pressure of the fluid to be detected, and the gauge resistance of the semiconductor gauge is changed in accordance with the deformation, and the change is taken out as an electric signal via the bridge circuit, whereby the pressure of the fluid is detected.

Disclosure of Invention

Problems to be solved by the invention

In the pressure sensor using the semiconductor pressure sensor sheet, when the ambient temperature changes, thermal stress is generated due to a difference in linear expansion coefficient among the semiconductor pressure sensor sheet, the supporting member supporting the semiconductor pressure sensor sheet, and the adhesive. That is, for example, when the ambient temperature is lowered, the adhesive having a larger linear expansion coefficient than the semiconductor pressure sensor sheet contracts, and when the ambient temperature is raised, the adhesive expands than the semiconductor pressure sensor sheet. In this case, the semiconductor pressure sensor sheet is restrained by the adhesive, so that thermal stress is generated between the semiconductor pressure sensor sheet and the adhesive. Further, thermal stress is also generated between the adhesive and the support member for the same reason.

The following problems have been known: the semiconductor pressure sensor sheet is deformed by the occurrence of such thermal stress, and the output characteristics of the semiconductor pressure sensor sheet change, whereby the accuracy of the sensor output of the semiconductor pressure sensor sheet is degraded. In the semiconductor pressure sensor sheet, as described above, the fluid is introduced into the diaphragm portion formed inside to detect the pressure, and if the semiconductor pressure sensor sheet is deformed, the diaphragm portion inside is also deformed, and the pressure cannot be accurately detected, which causes a decrease in accuracy of the sensor output of the semiconductor pressure sensor sheet. Further, the following problems have been known: the accuracy deteriorates due to the viscoelastic property of the adhesive and due to the delay in the temperature responsiveness of the pressure sensor.

In view of such conventional problems, patent document 1 discloses the following invention of a pressure detection device: by providing the connection portion connected at a tensile elongation of 400% or more and the protrusion portion provided at the bottom surface of the element storage portion at a position corresponding to the outer peripheral portion of the bottom surface of the pressure detection element, stress is buffered by a good elongation characteristic, and thermal responsiveness is extremely good. However, in patent document 1, since the pressure detection element is disposed in the element storage portion that is a rectangular hole provided in the base unit portion, there is a concern that the element storage portion restricts the side wall of the pressure detection element, and there is a problem that maintenance and management of the dimensional accuracy of the protrusion inside the rectangular hole are difficult. Further, there are also the following problems: the adhesive coating amount is unstable due to the viscosity of the adhesive, and the adhesive that has overflowed from the rectangular hole restricts the pressure detection element, or the adhesive layer has a thickness lower than the height of the protrusion provided at the bottom of the rectangular hole and the pressure detection element is not adhered, and the adhesive state varies, and the temperature responsiveness of the sensor output and the accuracy of the sensor output become unstable.

Accordingly, an object of the present invention is to provide a pressure sensor using a semiconductor pressure sensor sheet such as a piezoresistive effect type, in which the shape and processing accuracy of parts are controlled, so that a uniform thickness of an adhesive layer can be obtained, and the accuracy of sensor output can be improved by reducing the deformation of the semiconductor pressure sensor sheet due to the difference in linear expansion coefficients of the semiconductor pressure sensor sheet, a supporting member, an adhesive, and the like, which is conventionally caused by temperature change.

Means for solving the problems

In order to solve the above problem, a pressure sensor according to the present invention includes: a semiconductor pressure sensor sheet having a diaphragm portion therein; a support member that supports the semiconductor pressure sensor sheet; and an adhesive layer that adheres and fixes the semiconductor pressure sensor sheet to the support member, wherein the pressure sensor is characterized in that a protrusion that does not come into contact with the semiconductor pressure sensor sheet and a sensor sheet support that comes into contact with the semiconductor pressure sensor sheet are formed on the support member, the adhesive layer is formed on the protrusion, and the thickness of the adhesive layer is determined by a gap between the protrusion and the sensor sheet support.

Preferably, the sensor sheet support portion is formed around the protrusion portion via a groove formed between the protrusion portion and the sensor sheet support portion.

Preferably, the bonding region of the protrusion formed on the support member is located inside a projection of the diaphragm portion of the semiconductor pressure sensor sheet with respect to the support member.

Preferably, the support member is a metal pillar fixed to the outside in an insulated manner.

Preferably, the support member is a base constituting a housing of the pressure sensor.

Preferably, the base is formed of a conductive material.

Preferably, the base is made of an insulating material.

Preferably, the support member further includes a mounting substrate disposed in the liquid sealing chamber and supporting the semiconductor pressure sensor chip.

Preferably, the mounting substrate is formed of an insulating material.

Preferably, a conductive material is bonded to one surface of the mounting substrate on which the semiconductor pressure sensor chip is fixed.

Preferably, a protrusion is formed on the support member around the sensor sheet support portion in contact with the semiconductor pressure sensor sheet, and an adhesive layer is formed on the protrusion.

The effects of the invention are as follows.

According to the pressure sensor of the present invention, in the pressure sensor using the semiconductor pressure sensor sheet of piezoresistive effect type or the like, by managing the shape of the parts and the processing accuracy, it is possible to obtain a uniform thickness of the adhesive layer, and it is possible to reduce the deformation of the semiconductor pressure sensor sheet due to the difference in linear expansion coefficient of the semiconductor pressure sensor sheet, the supporting member, the adhesive agent, and the like caused by the conventional temperature change, and to improve the accuracy of the sensor output.

Drawings

Fig. 1 is a longitudinal sectional view showing the entire liquid-sealed pressure sensor, which is a first embodiment of the pressure sensor according to the present invention.

Fig. 2 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip of a conventional pressure sensor.

Fig. 3 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip of the pressure sensor shown in fig. 1.

Fig. 4 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip of a second embodiment of the pressure sensor of the present invention.

Fig. 5 is a vertical sectional view showing a mounting structure of a semiconductor pressure sensor chip of a third embodiment of the pressure sensor of the present invention.

Fig. 6 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip of a fourth embodiment of the pressure sensor of the present invention.

Fig. 7 is a vertical sectional view showing a mounting structure of a semiconductor pressure sensor chip in a fifth embodiment of the pressure sensor of the present invention.

Fig. 8 is a vertical sectional view showing a mounting structure of a semiconductor pressure sensor chip of a sixth embodiment of the pressure sensor of the present invention.

Fig. 9 is a graph showing a correlation between the thickness of the adhesive layer and the temperature responsiveness.

Fig. 10 is a longitudinal sectional view showing a modification of the mounting structure of the semiconductor pressure sensor chip of the first embodiment of the pressure sensor of the present invention.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

Note that the concept of the vertical direction or the horizontal direction in the following description corresponds to the vertical direction and the horizontal direction in the drawings, and shows the relative positional relationship of the respective members, not the absolute positional relationship.

First, a first embodiment of the present invention will be described.

Fig. 1 is a longitudinal sectional view showing the entire liquid-sealed pressure sensor 100 as a first embodiment of the pressure sensor according to the present invention.

In fig. 1, a liquid-sealed pressure sensor 100 includes: a fluid introduction unit 110 that introduces a fluid to be pressure-detected into a pressure chamber 112A described below; a pressure detection unit 120 that detects the pressure of the fluid in the pressure chamber 112A; a signal transmission unit 130 for transmitting the pressure signal detected by the pressure detection unit 120 to the outside; and a cover member 140 that covers the fluid introduction section 110, the pressure detection section 120, and the signal transmission section 130.

The fluid introduction unit 110 includes: a metal joint member 111 connected to a pipe for guiding a fluid to be pressure-detected; and a metal base plate member 112 having a bowl shape and connected to an end portion of the joint member 111, which is different from the end portion connected to the pipe, by welding or the like.

The joint member 111 has a female screw portion 111a that is screwed into a male screw portion of a connection portion of the pipe, and a port 111b that guides the fluid introduced from the pipe to the pressure chamber 112A. The opening end of the port 111b is connected to an opening provided in the center of the base plate 112 by welding or the like. Here, the joint member 111 is provided with the female screw portion 111a, but a male screw may be provided, or a copper connection pipe may be connected instead of the joint member 111. The base plate 112 has a bowl shape extending toward the side facing the joint member 111, and forms a pressure chamber 112A with a diaphragm 122 described below.

The pressure detection unit 120 includes: a housing 121 having a through hole; a diaphragm 122 for isolating the pressure chamber 112A from a liquid seal chamber 124A described below; a diaphragm protection cover 123 disposed on the pressure chamber 112A side of the diaphragm 122; a sealing glass 124 fitted in the through hole of the case 121; a liquid seal chamber 124A filled with a pressure transmission medium 124PM such as silicone oil or a fluorine-based inert liquid between the diaphragm 122 and a recess of the seal glass 124 on the pressure chamber 112A side; a support column 125 disposed in a through hole in the center of the sealing glass 124; a semiconductor pressure sensor chip 126 fixed to the support column 125 and disposed inside the liquid sealing chamber 124A; a potential adjusting member 127 disposed around the liquid sealing chamber 124A; a plurality of terminal pins 128 fixed to the sealing glass 124; and an oil filling tube 129 fixed to the sealing glass 124.

The case 121 is made of a metal material such as Fe, Ni alloy, and stainless steel. Both the diaphragm 122 and the diaphragm cover 123 are made of a metal material, and are welded to the outer peripheral edge of the through hole of the casing 121 on the pressure chamber 112A side. In order to protect the diaphragm 122, a diaphragm cover 123 is provided inside the pressure chamber 112A, and the diaphragm cover 123 is provided with a plurality of communication holes 123a for passing the fluid introduced from the fluid introduction portion 110. After the pressure detection unit 120 is assembled, the case 121 is joined to the outer peripheral edge of the base plate 112 of the fluid introduction unit 110 by welding or the like.

The support column 125 adhesively fixes the semiconductor pressure sensor sheet 126 to the liquid seal chamber 124A side with an adhesive layer 125A. The semiconductor pressure sensor chip 126 detects the pressure of the fluid introduced from the fluid introduction portion 110 into the pressure chamber 112A as described above as a pressure variation of the pressure transmission medium 124PM in the liquid seal chamber 124A via the diaphragm 122. The mounting structure of the semiconductor pressure sensor chip 126 will be described in detail with reference to fig. 3 described below.

As described in patent document 2, the semiconductor pressure sensor chip 126 is placed in a non-electric field (zero potential), and a potential adjusting member 127 is provided so that the circuits and the like in the chip are not adversely affected by the influence of the potential generated between the frame ground and the secondary power supply. The potential adjustment member 127 is disposed between the semiconductor pressure sensor chip 126 and the diaphragm 122 in the liquid sealed chamber 124A, is formed of a conductive material such as a metal, and is connected to a terminal of the semiconductor pressure sensor chip 126, which is connected to a zero potential.

The plurality of terminal pins 128 and the oil filling tube 129 are fixed to the sealing glass 124 by a sealing process in a penetrating state. In the present embodiment, all of the lead pins 128 are provided with eight lead pins 128. That is, three pins 128 for external input/output (Vout), drive voltage supply (Vcc), and Ground (GND), and five pins 128 as terminals for adjustment of the semiconductor pressure sensor chip 126 are provided. In addition, in fig. 1, four of the eight terminal pins 128 are shown. The plurality of terminal pins 128 are connected to the semiconductor pressure sensor chip 126 by bonding wires 126A made of, for example, gold or aluminum, and constitute external input/output terminals of the semiconductor pressure sensor chip 126.

An oil filling pipe 129 is provided to fill the pressure transmission medium 124PM into the hydraulic seal chamber 124A. Further, one end of the oil filling pipe 129 is deflated and closed as shown by a broken line in fig. 1 after being filled with oil.

The signal transmitting unit 130 includes: a terminal block 131 provided on the side of the pressure detection unit 120 facing the pressure chamber 112A and having a plurality of terminal pins 128 arranged therein; a plurality of connection terminals 132 fixed to the terminal block 131 with an adhesive 132a and connected to the plurality of terminal pins 128; a plurality of wires 133 electrically connected to outer end portions of the plurality of connection terminals 132 by soldering or the like; and an electrostatic protection layer 134 formed between the upper end of the case 121 and the terminal block 131 by a silicone adhesive. The electrostatic protection layer 134 may be an adhesive such as epoxy resin.

The terminal block 131 has a substantially cylindrical shape, is formed in a shape having a guide wall for guiding the plurality of terminal pins 128 in the vicinity of the middle section of the cylinder, and is formed of a resin material such as polybutylene terephthalate (PBT). The terminal block 131 is fixed to the upper portion of the case 121 of the pressure detection unit 120 by an adhesive used for the electrostatic protection layer 134, for example.

The connection terminal 132 is made of a metal material, and is vertically fixed to a cylindrical side wall of the terminal block 131 above the fixing wall by an adhesive 132 a. In the present embodiment, three connection terminals 132 for external input/output (Vout), drive voltage supply (Vcc), and Ground (GND) are provided. The inner ends of the three connection terminals 132 are electrically connected to the corresponding terminal pins 128 by soldering or the like, but the connection method is not limited thereto, and the connection may be performed by another method.

In the present embodiment, three electric wires 133 are provided to connect to the three connection terminals 132. The electric wire 133 is prepared by soldering the core wire 133a of the electric wire 133 from which the outer covering made of polyvinyl chloride (PVC) or the like is peeled off, bundling the twisted wires, and then electrically connecting the wires to the connection terminal 132 by soldering, welding, or the like, but the connection method is not limited thereto and the wires may be connected by another method. The three wires 133 are drawn out from the cover member 140 covering the periphery of the pressure sensor 100, and then bundled together, and are covered with a protective tube (not shown) made of polyvinyl chloride (PVC) or the like.

The electrostatic protection layer 134 is provided to improve the electrostatic durability of the pressure detection unit 120 without being affected by the presence or absence of the ESD protection circuit. The electrostatic protection layer 134 is mainly composed of an adhesive layer 134a and a coating layer 134b, wherein the adhesive layer 134a is formed of a silicone adhesive and has a predetermined thickness, and is applied to the upper end surface of the case 121 so as to cover the upper end surface of the sealing glass 124, and the coating layer 134b is composed of a silicone adhesive and is applied to the entire upper end surface of the sealing glass 124 from which the plurality of terminal pins 128 protrude. An annular protrusion 131a protruding toward the sealing glass 124 is formed on the inner circumferential surface facing the upper end surface of the sealing glass 124, which forms the cavity of the terminal block 131. The protruding length of the annular protrusion 131a is set according to the viscosity of the covering layer 134 b. By forming the annular protrusion 131a in this manner, a part of the coating layer 134b after coating is held in a narrow space between the annular protrusion 131a and a portion of the inner peripheral surface of the terminal block 131 forming the hollow portion, which is substantially perpendicular to the upper end surface of the sealing glass 124, by being pulled by surface tension, and the coating layer 134b is applied without being biased to one side in the hollow portion of the terminal block 131. The covering layer 134b is formed to a predetermined thickness on the upper end surface of the sealing glass 124, but may be formed to further cover a part of the plurality of terminal pins 128 protruding from the upper end surface of the sealing glass 124 as shown in a part 134c in fig. 1.

The cover member 140 includes: a waterproof case 141 having a substantially cylindrical shape and covering the pressure detecting unit 120 and the signal transmitting unit 130; a terminal block cover 142 covering an upper portion of the terminal block 131; and a sealant 143 filled between the inner peripheral surface of the waterproof case 141 and the outer peripheral surfaces of the case 121 and the terminal block 131.

The terminal block cover 142 is formed of, for example, a resin material. In the present embodiment, the terminal block cover 142 is formed in a shape to close the upper portion of the cylindrical terminal block 131, and covers the upper portion of the terminal block 131 before the sealing agent 143 such as urethane resin is filled. However, the terminal block cover 142 is not limited to this shape, and may be formed in a shape in which the upper portion of the terminal block 131 and the upper portion of the waterproof case 141 are sealed as a single body and covered after the sealing agent 143 is filled, or a new cover member may be provided separately from the terminal block cover 142 and covered on the upper portion of the waterproof case 141 after the terminal block cover 142 and the sealing agent 143 are disposed.

The waterproof case 141 is formed of a resin material such as polybutylene terephthalate (PBT) and is formed into a substantially cylindrical shape, and a flange portion facing inward is provided at a lower end portion of the cylindrical shape. The outer peripheral portion of the base plate 112 of the fluid introduction portion 110 to which the signal transmission portion 130 and the pressure detection portion 120 inserted from the opening portion of the upper portion of the waterproof case 141 are connected abuts on the flange portion. By filling the sealant 143 in this state, the internal components such as the pressure detecting portion 120 are fixed.

Next, the mounting structure of the semiconductor pressure sensor chip 126 will be described in detail. First, a mounting structure of a conventional semiconductor pressure sensor chip 126 will be described with reference to fig. 2.

Fig. 2 is a longitudinal sectional view showing a mounting structure of the semiconductor pressure sensor chip 126 of the conventional pressure sensor 200.

In fig. 2, the semiconductor pressure sensor sheet 126 of the conventional pressure sensor 200 is fixed by an adhesive layer 225A applied to the entire surface of the support column 225. After the semiconductor pressure sensor chip 126 is fixed with the adhesive layer 225A in this manner, lead terminals (not shown) of the semiconductor pressure sensor chip 126 and the plurality of terminal pins 128 are connected with bonding wires 126A made of gold or aluminum through a wire bonding process.

As shown in fig. 2, in the conventional pressure sensor 200, since the adhesive layer 225A is formed on the entire surface of the support column 225, the restriction force of the adhesive layer 225A and the support column 225 against the semiconductor pressure sensor sheet 126 is increased. Therefore, the semiconductor pressure sensor sheet 126 may be deformed due to the influence of the thermal stress caused by the difference in the linear expansion coefficients. That is, for example, when the ambient temperature decreases, the adhesive layer 225A having a larger linear expansion coefficient than the semiconductor pressure sensor sheet 126 contracts, and when the ambient temperature increases, the adhesive layer 225A expands than the semiconductor pressure sensor sheet 126. In this case, thermal stress is generated between the semiconductor pressure sensor sheet 126 and the adhesive layer 225A, and also between the adhesive layer 225A and the support column 225 for the same reason. The semiconductor pressure sensor chip 126 may be deformed by the thermal stress generated in this manner.

When the semiconductor pressure sensor chip 126 is deformed in this way, the output characteristics of the semiconductor pressure sensor chip 126 change, and the accuracy of the sensor output of the semiconductor pressure sensor chip 126 decreases. Further, it is also known that, due to the viscoelastic properties of the adhesive layer 225A, it takes time until the stress reaches an equilibrium state after the thermal stress changes, and the temperature responsiveness of the pressure sensor 200 deteriorates, but there is a problem that: as described above, since the restraining force is strong, this influence should be considered.

The mounting structure of the semiconductor pressure sensor chip 126 of the pressure sensor according to the present invention, which has been devised to solve the above-described conventional problems, will be described in detail with reference to fig. 3.

Fig. 3 is a longitudinal sectional view showing a mounting structure of the semiconductor pressure sensor chip 126 of the pressure sensor 100 shown in fig. 1.

In the pressure sensor 100 shown in fig. 1 and 3, the semiconductor pressure sensor sheet 126 is fixed to the support column 125 as a support member via an adhesive layer 125A.

As the semiconductor pressure sensor chip 126, a component in which a diaphragm portion is formed inside like a piezoresistive effect system is used here. The semiconductor pressure sensor chip 126 utilizing the piezoresistive effect is mainly configured by a semiconductor substrate portion 126a and a pedestal portion 126b, wherein the semiconductor substrate portion 126a has a diaphragm portion 126a1 made of a material having the piezoresistive effect (for example, single crystal silicon), and the pedestal portion 126b is made of glass or the like. The semiconductor substrate portion 126a and the pedestal portion 126b are bonded by anodic bonding or the like, and a space between the diaphragm portion 126a1 of the semiconductor substrate portion 126a and the pedestal portion 126b becomes a reference pressure chamber. A plurality of semiconductor strain gauges are formed on the diaphragm portion 126a1 of the semiconductor substrate portion 126a, and the semiconductor strain gauges are bridged to form a bridge circuit. With this bridge circuit, the deformation of the diaphragm portion 126a1 due to the pressure difference between the external air pressure and the reference pressure chamber is regarded as a change in the gauge resistance of the semiconductor gauge, and an electric signal is taken out to detect the pressure of the fluid.

As the adhesive layer 125A, silicone-based, urethane-based, fluorine-based adhesive, gel, rubber, or elastomer may be used.

Here, the support 125 is made of a metal material such as Fe, Ni alloy, and stainless steel. On the surface of the support column 125 facing the semiconductor pressure sensor chip 126, an in-groove convex portion 125a and a sensor chip support portion 125c are formed, wherein the in-groove convex portion 125a is a flat protrusion formed at the center, and the sensor chip support portion 125c is an annular protrusion formed around the support column 125 with a groove 125b spaced from the in-groove convex portion 125 a. Here, the semiconductor pressure sensor chip 126 is in close contact with the sensor chip support portion 125c of the support column 125, but is not in contact with the in-groove projection 125 a. Here, the sensor piece support portion 125c has a circular ring shape, but is not limited to this, and may have a polygonal column shape or may be formed as an annular projection portion that is interrupted a plurality of times.

The adhesive layer 125A is formed on the in-groove convex portion 125A formed on the support 125, but not on the sensor sheet support portion 125 c. Therefore, the thickness of the adhesive layer 125A is determined by the gap Δ g between the in-groove convex portion 125A and the sensor piece support portion 125c in contact with the semiconductor pressure sensor piece 126.

Fig. 9 is a graph showing a correlation between the thickness of adhesive layer 125A and the temperature responsiveness.

In fig. 9, the vertical axis shows the output accuracy of the semiconductor pressure sensor sheet 126 after the temperature changes from high temperature to low temperature, and the horizontal axis shows the thickness of the adhesive layer 125A. As a result, it is found that when the thickness of the adhesive layer 125A is larger than 5 μm, deterioration of the output accuracy of the semiconductor pressure sensor sheet 126 due to delay in temperature response is prevented. It is considered that when the thickness of the adhesive layer 125A is smaller than a predetermined thickness, the semiconductor pressure sensor sheet 126 is deformed by thermal stress generated by the difference in linear expansion coefficient among the semiconductor pressure sensor sheet 126, the support column 125, and the adhesive layer 125A, and the output accuracy of the semiconductor pressure sensor sheet 126 is deteriorated, but when the thickness of the adhesive layer 125A is larger than the predetermined thickness, the thermal stress generated by the difference in linear expansion coefficient is absorbed by the elasticity of the adhesive layer 125A, and the deformation of the semiconductor pressure sensor sheet 126 is suppressed.

In this way, by determining the thickness of the adhesive layer 125A based on the gap Δ g between the groove inner protrusion 125A and the sensor piece support portion 125c, the adhesive layer 125A can be easily formed with a stable thickness. Further, the inner convex portion 125a and the sensor piece supporting portion 125c can be formed by processing the surface of the pillar 125 by cutting, etching, laser irradiation, pressing, or the like, so that the manufacturing process is easy, the height dimension is easy to manage, and the manufacturing man-hours can be suppressed. Further, since the groove 125b is provided between the groove convex portion 125A and the sensor piece support portion 125c, the excess adhesive flows into the groove 125b, and the adhesive area of the adhesive layer 125A does not increase, and the thickness of the adhesive layer 125A can be constantly maintained.

In the present embodiment, the adhesive layer 125A formed on the in-groove convex portion 125, which is a flat convex portion, has an adhesive area smaller than the projection area of the diaphragm portion 126a1 in the semiconductor pressure sensor piece 126 onto the support 125. By reducing the bonding area of the adhesive layer 125A in this manner, the restraining force for the semiconductor pressure sensor sheet 126 is weakened, and thermal stress caused by a difference in linear expansion coefficients between the semiconductor pressure sensor sheets can be suppressed, and deformation of the semiconductor pressure sensor sheet 126 can be prevented.

That is, when only a portion corresponding to a deformed portion such as the diaphragm portion 126a1, which is repeatedly deformed by introducing a fluid for detection, is used as the adhesion region, the deformation is less likely to occur, and when a portion around the non-deformed diaphragm portion 126a1 is used as the adhesion region, the semiconductor pressure sensor chip 126 is more firmly restricted, and the deformation is likely to occur due to thermal stress, thereby deteriorating the detection accuracy. Therefore, the accuracy of the sensor output can be improved by making the bonding area of the adhesive layer 125A smaller than the projection area of the diaphragm portion 126a1 inside the semiconductor pressure sensor piece 126 onto the support 125.

In the present embodiment, the groove inner convex portion 125a is formed at the center of the pillar 125, and the sensor piece support portion 125c is formed as an annular protrusion portion that is formed around the pillar 125 by forming the groove 125b at a distance from the groove inner convex portion 125a, but the present invention is not limited thereto. That is, as shown in a modification 1000 of the present embodiment shown in fig. 10, a sensor piece support portion 1025c that abuts the semiconductor pressure sensor piece 126 may be provided at the center of the stay 1025, and a protrusion 1025A that forms an adhesive layer 1025A may be provided around the stay 1025 via a groove 1025b without coming into contact with the semiconductor pressure sensor piece 126. The sensor piece support portion 1025c may have a flat surface to a degree that the semiconductor pressure sensor piece 126 can be held at a stable inclination, and the protrusion 1025A may be formed to have a height that forms an adhesive layer 1025A of a constant thickness with the semiconductor pressure sensor piece 126.

As described above, according to the first embodiment of the present invention, the adhesive layer is formed on the protruding portion formed on the support member, and the thickness of the adhesive layer is determined according to the gap Δ g between the protruding portion and the sensor sheet support portion. The gap Δ g and the size of the protrusion are formed by the protrusion shape machined on the support 125, so that the thickness of the adhesive layer and the size of the adhesive region can be easily controlled. Thus, in the pressure sensor using the semiconductor pressure sensor sheet of the piezoresistive effect type or the like, the strain of the semiconductor pressure sensor sheet caused by the difference in the linear expansion coefficient of the semiconductor pressure sensor sheet, the supporting member, the adhesive, or the like due to the conventional temperature change can be reduced, and the accuracy of the sensor output can be improved.

Next, a second embodiment of the present invention will be explained.

Fig. 4 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip 126 of a second embodiment of the pressure sensor of the present invention.

In fig. 4, the pressure sensor 400 is different from the pressure sensor 100 shown in fig. 1 and 3 in the structure in which the mounting substrate 425B is disposed between the support 425 and the semiconductor pressure sensor chip 126, and is otherwise the same as the pressure sensor 100. The same components are denoted by the same reference numerals, and description thereof is omitted.

The mounting substrate 425B is formed of an insulating material such as resin, glass, or ceramic, and is fixed to the support 425 by an adhesive or the like.

Here, a conductive layer may be formed on one surface of the mounting substrate 425B on which the semiconductor pressure sensor sheet 126 is fixed by bonding, vapor deposition, plating, photolithography, or the like. The conductive layer may be formed of a metal or alloy film of gold, silver, copper, aluminum, or the like. The conductive layer is connected to a terminal of the semiconductor pressure sensor chip 126 connected to a zero potential. In this way, by providing the conductive layer on the mounting board 425B and connecting the conductive layer to the zero potential, the semiconductor pressure sensor chip 126 is placed at the zero potential on the control circuit side, and the potential of the semiconductor pressure sensor chip 126 can be prevented from becoming unstable.

In the present embodiment, similarly, an in-groove convex portion 425Ba and a sensor piece supporting portion 425Bc are formed on the surface of the mounting substrate 425B serving as a supporting member facing the semiconductor pressure sensor piece 126, wherein the in-groove convex portion 425Ba is a flat protruding portion formed at the center, and the sensor piece supporting portion 425Bc is an annular protruding portion formed at the periphery with a groove 425Bb spaced from the in-groove convex portion 425 Ba. The adhesive layer 425A is formed on the groove inner protrusion 425Ba formed on the mounting substrate 425B, but not on the sensor piece supporting part 425 Bc. Therefore, the thickness of the adhesive layer 425A is determined by the gap Δ g between the in-groove convex portion 425Ba and the sensor piece supporting portion 425Bc in contact with the semiconductor pressure sensor piece 126. The sensor piece supporting portion 425Bc is formed as an annular projection, but is not limited thereto, and the gap Δ g may be formed between the groove 425Bb and the groove inner projection 425Ba, and need not be formed as a projection.

As described above, according to the pressure sensor 400 of the second embodiment of the present invention, the same operational effects as those of the pressure sensor 100 of the first embodiment can be obtained. Further, since the mounting substrate 425B mounted on the support 425 may be processed, the processing is further facilitated, and the number of manufacturing steps can be reduced.

Next, a third embodiment of the present invention will be explained.

Fig. 5 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip 126 of a third embodiment of the pressure sensor of the present invention.

In fig. 5, the pressure sensor 500 is different from the pressure sensor 100 shown in fig. 1 and 3 in the following points: as the support member, a base 525 constituting a housing of the pressure sensor 500 is provided instead of the support column 125, and the semiconductor pressure sensor sheet 126 is fixed to the base 525 via an adhesive layer 525A.

In the present embodiment, the base 525 is formed of a conductive material such as a metal including stainless steel. Therefore, the plurality of terminal pins 528 are connected to the semiconductor pressure sensor chip 126 by the bonding wires 126A, and the plurality of terminal pins 528 are fixed to the base 525 so as to penetrate through the insulating sealing glass 524.

In the present embodiment, similarly, an in-groove convex portion 525a and a sensor piece supporting portion 525c are formed on a surface of the base 525 serving as a supporting member facing the semiconductor pressure sensor piece 126, the in-groove convex portion 525a being a flat protruding portion formed at the center, and the sensor piece supporting portion 525c being a circular protruding portion formed in the periphery of the in-groove convex portion 525a with the groove 525b being spaced apart from the in-groove convex portion 525 a. The adhesive layer 525A is formed on the groove-shaped projection 525A formed on the base 525, but not on the sensor piece supporting portion 525 c. Therefore, the thickness of the adhesive layer 525A is determined by the gap Δ g between the in-groove convex portion 525A and the sensor piece supporting portion 525c in contact with the semiconductor pressure sensor piece 126. The sensor piece supporting portion 525c is formed as an annular projection, but is not limited thereto, and the gap Δ g may be formed between the groove 525b and the groove inner projection 525a, and need not be formed as a projection.

As described above, the pressure sensor 500 according to the third embodiment of the present invention can also provide the same operational advantages as the pressure sensor 100 according to the first embodiment.

Next, a fourth embodiment of the present invention will be explained.

Fig. 6 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip 126 of a fourth embodiment of the pressure sensor of the present invention.

In fig. 6, the pressure sensor 600 is different from the pressure sensor 500 shown in fig. 5 in the structure in which the mounting substrate 625B is disposed between the base 625 made of a conductive material made of stainless steel and the semiconductor pressure sensor chip 126, and is otherwise the same as the pressure sensor 500. The same components are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, similarly, on the mounting substrate 625B serving as a support member, a groove inner protrusion 625Ba and a sensor piece support portion 625Bc are formed on the surface facing the semiconductor pressure sensor piece 126, wherein the groove inner protrusion 625Ba is a flat protrusion formed at the center, and the sensor piece support portion 625Bc is a circular protrusion formed in the periphery with a groove 625Bb spaced from the groove inner protrusion 625 Ba. The adhesive layer 625A is formed on the in-groove convex portion 625Ba formed on the mounting substrate 625B, but not on the sensor piece supporting portion 625 Bc. Therefore, the thickness of the adhesive layer 625A is determined by the gap Δ g between the in-groove convex portion 625Ba and the sensor piece supporting portion 625Bc in contact with the semiconductor pressure sensor piece 126.

As described above, the pressure sensor 600 according to the fourth embodiment of the present invention can also provide the same operational advantages as the pressure sensor 500 according to the third embodiment. Further, since the mounting substrate 625B mounted on the base 625 is processed, the processing is further facilitated, and the number of manufacturing steps can be reduced.

Next, a fifth embodiment of the present invention will be described.

Fig. 7 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip 126 in a fifth embodiment of the pressure sensor of the present invention.

In fig. 7, a pressure sensor 700 differs from the pressure sensor 500 shown in fig. 5 in the following respects: as the support member, a base 725 made of an insulating material such as resin or ceramic is provided instead of the base 525 made of a conductive material such as metal, and the semiconductor pressure sensor sheet 126 is fixed to the base 725 via an adhesive layer 725A.

In addition, in the present embodiment, by using an insulating material such as resin or ceramic as the base 725, workability of the material can be improved and man-hours can be reduced, and further, it is not necessary to use insulating sealing glass for fixing the plurality of conductive terminal pins 728, and manufacturing cost can be suppressed to a low level.

In the present embodiment, similarly, a groove inner convex portion 725a and a sensor piece supporting portion 725c are formed on the surface of the base 725 serving as a supporting member facing the semiconductor pressure sensor piece 126, the groove inner convex portion 725a being a flat protruding portion formed at the center, and the sensor piece supporting portion 725c being a circular protruding portion formed in the periphery of the groove inner convex portion 725b at an interval from the groove inner convex portion 725 a. Adhesive layer 725A is formed on in-groove projection 725A formed on base 725, but not on sensor sheet support 725 c. Therefore, the thickness of the adhesive layer 725A is determined by the gap Δ g between the in-groove projection 725A and the sensor sheet support portion 725c that abuts the semiconductor pressure sensor sheet 126. The sensor piece supporting portion 725c is formed as a circular ring-shaped protrusion, but is not limited thereto, and the gap Δ g may be formed between the groove 725a and the groove inner protrusion via the groove 725b, and need not be formed as a protrusion.

As described above, according to the pressure sensor 700 of the fifth embodiment of the present invention, the same operational effects as those of the pressure sensor 500 of the third embodiment can be obtained, and since the base 725 made of an insulating material such as resin or ceramic is processed, the workability of the material can be improved and the number of steps can be reduced.

Next, a sixth embodiment of the present invention will be explained.

Fig. 8 is a longitudinal sectional view showing a mounting structure of a semiconductor pressure sensor chip 126 of a sixth embodiment of the pressure sensor of the present invention.

In fig. 8, the pressure sensor 800 is different from the pressure sensor 700 shown in fig. 7 in the structure in which the mounting substrate 825B is disposed between the base 825 formed of an insulating material such as resin or ceramic and the semiconductor pressure sensor sheet 126, and is otherwise the same as the pressure sensor 700. The same components are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, similarly, on the mounting substrate 825B serving as a support member and on the surface facing the semiconductor pressure sensor chip 126, a groove inner convex portion 825Ba and a sensor chip support portion 825Bc are formed, in which the groove inner convex portion 825Ba is a flat convex portion formed at the center, and the sensor chip support portion 825Bc is a circular convex portion formed in the periphery of the groove 825Bb spaced apart from the groove inner convex portion 825 Ba. The adhesive layer 825A is formed on the groove inner projection 825Ba formed on the mounting substrate 825B, but not on the sensor chip support portion 825 Bc. Therefore, the thickness of the adhesive layer 825A is determined by the gap Δ g between the in-groove projection 825Ba and the sensor chip support portion 825Bc in contact with the semiconductor pressure sensor chip 126.

As described above, the pressure sensor 800 according to the sixth embodiment of the present invention can also provide the same operational advantages as the pressure sensor 700 according to the fifth embodiment. Further, since the mounting board 825B mounted on the base 825 only needs to be processed, the processing becomes further easy, and the number of manufacturing steps can be reduced.

Further, the pressure sensor of the present invention has been described by taking the liquid-sealed pressure sensors of the first to sixth embodiments as an example, but the present invention is not limited to this, and can be applied to other pressure sensors using a semiconductor pressure sensor sheet such as a piezoresistive effect type.

As described above, according to the pressure sensor of the present invention, the adhesive layer is formed on the protruding portion formed on the support member, and the thickness of the adhesive layer is determined according to the gap Δ g between the protruding portion and the sensor piece support portion. The gap Δ g and the size of the protrusion are formed by the shape machined in the support member, so that the thickness of the adhesive layer and the size of the adhesive region can be easily controlled. Thus, in the pressure sensor using the semiconductor pressure sensor sheet of the piezoresistive effect type or the like, the strain of the semiconductor pressure sensor sheet caused by the difference in the linear expansion coefficient of the semiconductor pressure sensor sheet, the supporting member, the adhesive, or the like due to the conventional temperature change can be reduced, and the accuracy of the sensor output can be improved.

Description of the symbols

100. 400, 500, 600, 700, 800, 1000-pressure sensor, 110-fluid inlet portion, 111-connector member, 111 a-female screw portion, 111 b-port, 112-base plate, 112A-pressure chamber, 120-pressure detecting portion, 121-housing, 122-diaphragm, 123-diaphragm protecting cover, 123 a-communication hole, 124, 524-sealing glass, 124A-liquid sealing chamber, 125, 425-pillar, 125A, 425Ba, 525A, 625Ba, 725A, 825 Ba-groove inner convex portion, 125b, 425Bb, 525b, 625Bb, 725b, 825Bb, 1025 b-groove, 125c, 425Bc, 525c, 625Bc, 725c, 825Bc, 1025 c-sensor sheet support portion, 125A, 425A, 525A, 625A, 725A, 825A, 1025A-adhesive layer, 126-semiconductor pressure sensor sheet, 126A-semiconductor substrate portion, 126A 78-base portion, 1-seat portion, 126A-stage lead portion, 126A-stage bonding pad portion, 127-potential adjusting member, 128, 528, 728-terminal pin, 129-oil filling tube, 130-signal sending part, 131-terminal block, 132-connection terminal, 132 a-adhesive, 133-electric wire, 133 a-core wire, 134-electrostatic protection layer, 134 a-adhesive layer, 134B-coating layer, 134 c-part, 140-cover member, 141-waterproof case, 142-terminal block cover, 143-sealant, 525, 625, 725, 825-base, 425B, 625B, 825B-mounting substrate, 1025 a-protrusion.