Pressure sensor and method for manufacturing pressure sensor

Abstract

Provided are: a method for manufacturing a pressure sensor that is provided with an oil other than a fluorine-based oil; and a pressure sensor. In the pressure sensor, a liquid medium is a methylphenylsilicone oil or a modified silicone oil, and a fixing part that fixes a pressure detection part is any one of a dimethylsilicone resin, a vinylmethylsilicone resin, a methylphenylsilicone resin, a fluorosilicone resin, or a modified silicone resin. Alternatively, the liquid medium is a dimethylsilicone oil and the fixing part is any one of a vinylmethylsilicone resin, a methylphenylsilicone resin, a fluorosilicone resin, or a modified silicone resin.

Description

Pressure sensor and method for manufacturing the pressure sensor

[0001] The present invention relates to a pressure sensor and a method for manufacturing a pressure sensor.

[0002] For example, a liquid-filled pressure sensor disclosed in Patent Document 1 has a configuration in which a semiconductor pressure detection device is housed in a pressure-receiving chamber partitioned by a diaphragm and filled with oil. In the pressure detection device, the pressure-receiving chamber is filled with oil as a liquid medium. This type of pressure sensor is used, for example, in freezers and refrigerators and air conditioners to detect refrigerant pressure, and in industrial equipment to detect various fluid pressures.

[0003] The semiconductor pressure detection device is disposed in the pressure receiving chamber and has the function of converting pressure changes of the oil in the pressure receiving chamber into an electric signal by means of a pressure detection element and outputting the signal to the outside.

[0004] Japanese Patent Application Laid-Open No. 2012-237612

[0005] Conventional pressure sensors often use silicone-based or fluorine-based oil as the liquid medium sealed in the pressure-receiving chamber. When silicone-based oil is used as the liquid medium, a fluorine-based adhesive is used as the adhesive for fixing the pressure detection device. Alternatively, when fluorine-based oil is used as the liquid medium, a silicone-based adhesive is used as the adhesive for fixing the pressure detection device. In recent years, from an environmental perspective, the use of other oils instead of fluorine-based oils has been considered. However, depending on the combination of oil and adhesive, there is a risk that the adhesive may denature (swell, etc.), making the combination of oil and adhesive a challenge.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a pressure sensor using oil other than fluorine-based oil, and a method for manufacturing the pressure sensor.

[0007] In order to achieve the above object, the pressure sensor of the present invention comprises: a base; a diaphragm provided on the base and forming a pressure-receiving chamber together with the base; a liquid medium filled in the pressure-receiving chamber; a fixing part provided on the base at a portion facing the pressure-receiving chamber; and a pressure detection device fixed to the fixing part and outputting a signal corresponding to the pressure in the pressure-receiving chamber, wherein the liquid medium is methylphenyl silicone oil or modified silicone oil, and the fixing part is any one of dimethyl silicone resin, vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin, or the liquid medium is dimethyl silicone oil, and the fixing part is any one of vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin.

[0008] A method for manufacturing a pressure sensor of the present invention includes a base, a diaphragm provided on the base and forming a pressure-receiving chamber together with the base, a liquid medium filled in the pressure-receiving chamber, a fixing portion provided on the base facing the pressure-receiving chamber and formed by hardening an adhesive, and a pressure detection device fixed to the fixing portion and outputting a signal corresponding to the pressure of the pressure-receiving chamber, the method comprising: a first step of supplying any one of dimethyl silicone resin, vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive; a second step of arranging the pressure detection device on the adhesive; and a third step of supplying methyl phenyl silicone oil or modified silicone oil to the pressure-receiving chamber as the liquid medium, or a fourth step of supplying any one of vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive instead of the first step. The method is characterized by comprising, instead of the third step, a fifth step of supplying dimethyl silicone oil as the liquid medium to the pressure-receiving chamber.

[0009] According to the present invention, it is possible to provide a pressure sensor including an oil other than a fluorine-based oil, and a method for manufacturing the pressure sensor.

[0010] Fig. 1 is a longitudinal cross-sectional view showing a pressure sensor according to an embodiment of the present invention. Fig. 2 is a bottom view of the pressure detection unit taken along the line A-A in Fig. 1. Fig. 3 is a side view of the pressure detection unit taken along the line B-B in Fig. 3. Fig. 4 is an enlarged view of the area indicated by arrow C in Fig. 3. Fig. 5 is a view showing a state in which adhesive has been applied to the recessed portion of the base.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a longitudinal cross-sectional view showing a pressure sensor 1 according to this embodiment. Fig. 2 is a bottom view of the pressure detection unit 2 taken along the line A-A in Fig. 1, with the welded portion W omitted. Fig. 3 is a side view of the pressure detection unit 2 taken along the line B-B in Fig. 3. Here, the cover 10 side is referred to as the upper side, and the pressure detection unit 2 side is referred to as the lower side.

[0012] 1, the pressure sensor 1 includes a cover 10, a pressure detection unit 2, and a relay board 90. The resin cover 10 has a large cylindrical portion 10a, for example, having a cylindrical cross section, and a small cylindrical portion 10b, for example, having an annular, oval, or elliptical cross section, which are arranged coaxially, with the ends of the large cylindrical portion 10a being molded with a step 10c interposed between them. The pressure detection unit 2 and the relay board 90 are attached to the inside of the large cylindrical portion 10a of the cover 10.

[0013] The pressure detection unit 2 includes a dish-shaped mounting member 30, a dish-shaped base 40 disposed opposite the mounting member 30, and a metal diaphragm 50 whose outer periphery is sandwiched between the mounting member 30 and the base 40. The mounting member 30, base 40, and diaphragm 50 may be made of, for example, a stainless steel alloy. The mounting member 30 has a hole 30a in the center into which the fluid inlet pipe 20 is fitted, and the fluid inlet pipe 20, whose end is fitted into the hole 30a, is fixed to the mounting member 30 by brazing or the like.

[0014] The outer peripheries of the mounting member 30, the base 40 and the diaphragm 50 are circumferentially welded, and the mounting member 30, the base 40 and the diaphragm 50 are integrated by the weld W formed thereby.

[0015] A pressure-receiving chamber 52 defined by the base 40 and the diaphragm 50 is filled with an insulating liquid medium. The diaphragm 50 separates the pressure-receiving chamber 52 from the fluid introducing chamber 32. The liquid medium will be described later.

[0016] This liquid medium is filled into the pressure-receiving chamber 52 through an opening 40a (FIG. 2) formed in the base 40, and then a metal ball 43, for example, is fixed to the base 40 by welding or other means to seal the chamber.

[0017] A semiconductor pressure sensor 60 is disposed in a rectangular recess 40b (FIG. 2) formed in the center of the surface of the base 40 facing the diaphragm 50 and facing the pressure-receiving chamber 52. The pressure sensor 60 comprises a glass base 62 and a pressure sensor element (semiconductor chip) 64 fixed to its surface. When viewed in the normal direction to the flat bottom surface of the recess 40b, the recess 40b, the base 62, and the pressure sensor element 64 have similar square shapes. The recess 40b is larger than the base 62, and there is a gap between the inner periphery of the recess 40b and the outer periphery of the base 62. An inner surface 40c (see FIG. 4, described later) that forms the inner periphery of the recess 40b is perpendicular to the bottom surface of the recess 40b. The base 62 and the pressure sensor element 64 have a square shape, but are not limited to this. Other shapes include a diamond, a rectangle, and a circle.

[0018] The pedestal 62 is fixed to the bottom surface of the recess 40b using an adhesive. The adhesive will be described later. The pedestal 62 is preferably formed of an insulating material or a semiconductor. For example, the pedestal 62 as the first substrate is not limited to being made of glass, but may be formed of ceramic, silicon, or other materials. The pressure detection element 64, on which the pressure detection circuit board is mounted, is formed from a second substrate disposed on the opposite side of the first substrate from the base 40. The second substrate is preferably formed of an insulating material or a semiconductor. The second substrate is not limited to being made of silicon, but may be formed of ceramic, glass, or other materials. The first substrate and the second substrate are each preferably parallel flat plates, and their side surfaces are preferably perpendicular to their top and bottom surfaces.

[0019] 2, the pressure detection element 64 has eight bonding pads (electrodes) near its periphery. Three of the bonding pads are a sensor input power supply pad 64a, a ground pad 64b, and a sensor output pad 64c, and the remaining five are signal adjustment pads 64d. However, the number of bonding pads is not limited to eight. In this embodiment, the sensor input power supply pad 64a is maintained at 5 V, the ground pad 64b is maintained at 0 V, and the voltage of the sensor output pad 64c varies within a range of 0 V to 5 V (preferably 0.5 V to 4.5 V) depending on the detected pressure. Furthermore, the arrangement of the bonding pads is not limited to the above.

[0020] A plurality of terminal pins 70, 72 (eight in this example) are arranged around the semiconductor pressure detection device 60, penetrating the base 40. The terminal pins 70, 72 are inserted through holes in the base 40, and are insulated and sealed by a hermetic seal 74. The surface of the base 40 around the pressure detection device 60 is plated to form a plated surface 40c on the pressure-receiving chamber side. While the plating in this embodiment is nickel plating, plating may also be performed with other materials (e.g., gold or copper) that have lower electrical resistance than the stainless steel diaphragm 50.

[0021] One of the multiple terminal pins is a ground terminal pin 70. The seven terminal pins 72 other than the ground terminal pins are connected to terminals of the wiring layer of the relay board 90 shown in Fig. 1, and the one ground terminal pin 70 is connected to the ground of the wiring layer of the relay board 90 shown in Fig. 1.

[0022] 1, relay board 90 is disposed within cover 10 together with pressure detection unit 2. Lead wires 94 connected to relay board 90 via connector 92 are connected to an electric circuit (not shown) provided in a control panel of a refrigeration / freezing device, air conditioner, or the like in which pressure sensor 1 is installed. From this electric circuit, a power supply voltage can be applied to pressure detection element 64 via lead wires 94 and terminal pins 70 and 72, and a pressure detection signal can also be output.

[0023] 2, in the semiconductor pressure detection device 60, the sensor input power supply pad 64a, the sensor output pad 64c, and the signal adjustment pad 64d, other than the ground pad 64b, are connected (wired) to the terminal pin 72 by bonding wires 80. In this embodiment, the ground pad 64b is connected (wired) to the ground terminal pin 70 via a bonding wire 82, and the plated surface 40c is connected (wired) to the ground terminal pin 70 via a bonding wire (not shown).

[0024] When assembling the pressure detection unit 2 to the cover 10, as shown in Figure 1, the outer peripheral flange 41 of the base 40 of the pressure detection unit 2 is placed inside the large cylindrical portion 10a of the cover 10. Then, resin R1 is filled into the interior of the cover 10 from the lower end side of the large cylindrical portion 10a and the upper end side of the small cylindrical portion 10b (the side from which the lead wires 94 are led out), and the resin R1 is allowed to harden. This seals and fixes the electrical structure of the pressure detection unit 2 within the cover 10.

[0025] The pressure detection device 60 operates by receiving power from an external electrical circuit via a terminal pin 71 for input power. When pressure is transmitted from the fluid in the fluid inlet pipe 20 to the fluid in the fluid introduction chamber (pressure chamber) 32 inside the mounting member 30, the diaphragm 50 elastically deforms due to the pressure, pressurizing the liquid medium in the pressure-receiving chamber 52. The pressure detection element 64 detects this pressure fluctuation, converts it into an electrical signal, and outputs the electrical signal, i.e., a pressure detection signal, to the outside via the terminal pin 72. The external electrical circuit that receives this pressure detection signal can then accurately detect the pressure of the fluid introduced into the fluid inlet pipe 20 based on the signal.

[0026] (Mounting of Pressure Detection Device) Next, the mounting of the pressure detection device 60 to the base 40 will be described. Fig. 4 is an enlarged view of the area indicated by arrow C in Fig. 3. The pedestal 62 is fixed to the recess 40b of the base 40 with adhesive BD.

[0027] The manufacturing method of the pressure sensor 1 comprises: a first step of supplying methylphenyl silicone oil or modified silicone oil as a liquid medium to the pressure-receiving chamber 52; a second step of supplying any one of dimethyl silicone resin, vinyl methyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin as an adhesive BD to the base; and a third step of placing the pressure detection device 60 on the adhesive BD; or alternatively, a fourth step of supplying dimethyl silicone oil as a liquid medium to the pressure-receiving chamber 52 instead of the first step; and a fifth step of supplying any one of vinyl methyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin as an adhesive BD to the base 40 instead of the second step.

[0028] The inventors investigated the relationship between the oil material used as the liquid medium and the adhesive material. Liquid silicone resin is used as the liquid medium and adhesive. Liquid silicone resins are either non-curable or curable. The non-curable type is silicone oil. The curable type is curable liquid silicone resin. Silicone oil has fluidity at room temperature (25°C) and its base polymer is an organopolysiloxane that does not have a curable functional group such as an alkenyl group. Silicone oil is used as the liquid medium filled into the pressure-receiving chamber 52. Silicone resins have an organopolysiloxane base polymer that has a curable functional group such as an alkenyl group at the end or side chain of the molecule, and are classified by crosslinking mechanism into addition reaction curing, condensation reaction curing, peroxide curing, etc. (1) Silicone oil is used as the liquid medium. The following silicone oils are used as the liquid medium: - Dimethyl silicone oil - Methylphenyl silicone oil - Modified silicone oil

[0029] Here, dimethyl silicone oils are available in linear and cyclic types, and either one or both are used. The linear type has a polyorganosiloxane structure, as shown in the following structural formula, and corresponds to a polyorganosiloxane in which all side chains and terminals are methyl groups. The n used in the structural formula is an integer of 1 or greater. The cyclic dimethyl silicone oil is represented by the following structural formula: The n used in the structural formula is an integer of 1 or more.

[0030] Methylphenyl silicone oil corresponds to a polyorganosiloxane structure in which some of the side chains are phenyl groups, as shown in the following structural formula. In addition, m and n used in the structural formula are integers of 1 or more.

[0031] The modified silicone oil corresponds to an oil in which part of the side chain in the polyorganosiloxane structure or one or both terminal portions of the polyorganosiloxane structure are various organic groups, as shown in the following structural formula. Each of m and n used in the structural formula is an integer of 1 or more.

[0032] (2) The adhesive BD is composed solely of a curable liquid silicone resin. Alternatively, the adhesive BD has a curable liquid silicone resin as its main component. The silicone resins used in the adhesive BD are as follows: Dimethyl silicone resin Vinyl methyl silicone resin Methyl phenyl silicone resin Fluorosilicone resin Modified silicone resin "Having a curable liquid silicone resin as its main component" means that in addition to the curable liquid silicone resin, additives are contained depending on the curing mode and purpose of the adhesive. Examples of additives include polysiloxane compounds used to adjust viscosity, catalysts used as curing agents, crosslinking agents used both as curing agents and to adjust hardness, retarders used to adjust the curing speed, and peroxides.

[0033] The curable liquid silicone resin will be described below taking an example of an addition crosslinking type curing resin (described later). The structural formula of the addition crosslinking type curable liquid silicone resin is expressed as follows: Note that n used in the structural formula is an integer of 1 or more, provided that: i) dimethyl silicone resin: R2 to R7: methyl groups, R1 and R8: alkenyl groups; ii) vinyl methyl silicone resin: R2 to R7: some of R2 to R7 are vinyl groups, and the remaining are organic groups such as alkyl groups, R1 and R8: alkenyl groups; iii) methyl phenyl silicone resin: R2 to R7: some of R2 to R7 are phenyl groups, and the remaining are organic groups such as alkyl groups, R1 and R8: alkenyl groups; iv) fluorosilicone resin: R2 to R7: some of R2 to R7 are perfluoroalkyl groups, and the remaining are organic groups such as alkyl groups, R1 and R8: alkenyl groups; v) modified silicone resin: R1 to R8: some of R1 to R8 are organic groups such as epoxy groups, and the remaining are organic groups and alkenyl groups.

[0034] When the adhesive BD hardens, it forms a fixing portion 100 that fixes the pressure detection device 60 to the base 40. The hardened adhesive BD (fixing portion 100) faces the pressure-receiving chamber 52.

[0035] As an example, when the material of the adhesive BD is an addition crosslinking type silicone resin, an example of the curing mode of the adhesive BD is shown below. In the following formula, the formula on the left is the adhesive material, and the formula on the right is the material of the fixing part after curing by the addition crosslinking type.

[0036] As a result of extensive research, the inventors have found that (1) when methylphenyl silicone oil or modified silicone oil is used as the liquid medium among silicone oil materials, (2) when pedestal 62 is fixed to base 40 using an adhesive made of any of all adhesive materials, fixing portion 100 is formed from hardened adhesive BD. This prevents or suppresses the occurrence of modification (swelling, etc.) in fixing portion 100 that fixes pedestal 62 to base 40, and as a result, it is possible to prevent or suppress the deterioration of the function of fixing pedestal 62 to base 40.

[0037] Alternatively, (1) when dimethyl silicone oil is used as the liquid medium among the silicone oil materials, (2) the same effect can be obtained by fixing the pedestal 62 to the base 40 using an adhesive made of any of vinyl methyl silicone resin, methyl phenyl silicone resin, fluorosilicone resin, and modified silicone resin among the adhesive materials.

[0038] However, the adhesive BD is not limited to a curing mode, and may be an addition crosslinking type (or addition type), a condensation crosslinking type (or condensation type), an ultraviolet crosslinking type, a peroxide type, a one-component type, or a two-component type.

[0039] Fig. 5 is a diagram showing a state in which adhesive BD has been applied to recess 40b of base 40. In Fig. 5, when viewed in the direction normal to the bottom surface of recess 40b (perpendicular to the paper surface of Fig. 5), the inner periphery of recess 40b is square, with the direction of one side of the square being the X direction and the direction perpendicular to the X direction being the Y direction.

[0040] The adhesive BD is applied to the bottom surface of the recess 40b from an adhesive dispenser (not shown) that is movable relative to the base 40 in the X and Y directions. When applying the adhesive, it is preferable to hold the base 40 upside down relative to the base 40 shown in FIG. 4 and move the adhesive dispenser relative to the base 40 to apply the adhesive using gravity. First, in FIG. 5, the adhesive dispenser is moved relative to the base 40b in the X direction, the Y direction, a direction tilted +45 degrees relative to the X direction, and a direction tilted -45 degrees relative to the X direction to apply the adhesive sequentially, stopping just before the inner periphery on the opposite side. The application order is not limited to the above. Furthermore, the base 62 to which the pressure detection element 64 is fixed is pressed against the adhesive applied to the recess 40b. The adhesive BD is then cured using a curing device appropriate for the curing mode of the adhesive BD. Wire bonding and other processes are then performed.

[0041] According to the above application method, air bubbles are unlikely to remain between the bottom surface of the base 62 and the opposing surface of the recess 40b, so that the adhesive strength of the base 62 can be ensured.

[0042] The amount of adhesive BD applied is determined so that when the base 62 is pressed against the recess 40b after application, a portion of the adhesive BD wraps around the periphery of the base 62. Therefore, the fixing portion 100 is composed of an adhesive base (also simply referred to as a base) BD1 located between the bottom surface of the base 62 and the opposing surface of the recess 40b, and an adhesive periphery (also simply referred to as a periphery) BD2 located in the gap between the inner periphery of the recess 40b and the outer periphery of the base 62 and surrounding the entire periphery of the base 62. This not only further ensures the adhesive strength of the base 62 but also prevents the liquid medium in the pressure-receiving chamber 52 from penetrating between the bottom surface of the base 62 and the opposing surface of the recess 40b. It is preferable that the cross-sectional area of ​​the adhesive periphery BD2, perpendicular to the normal to the bottom surface of the recess 40b, decreases with increasing distance from the bottom surface of the recess 40b. That is, the fixing portion 100 provided in the recess 40b includes a base portion BD1 disposed between the bottom surface of the base 40 and the pedestal 62 and in contact with the bottom surface and the pedestal 62, and a peripheral portion BD2 disposed between the inner peripheral surface 40d of the recess 40b and the outer peripheral surface of the pedestal 62 and in contact with the inner peripheral surface and the outer peripheral surface. The width of the gap between the inner peripheral surface 40d of the recess 40b and the outer peripheral surface of the pedestal 62 is constant in the circumferential direction, but is not limited thereto. "Constant" does not necessarily mean a strict uniform width, but also includes "approximately constant" that takes into account errors such as installation tolerances. However, if the base portion BD1 is polygonal when viewed in the direction normal to the bottom surface, the gap at the corners is excluded from the "constant" definition. On the other hand, if the corners of the bottom surface are rounded (arcuate), the corners are also constant. When the peripheral portion BD2 is cut along a plane normal to the bottom surface of the recess 40b, the cross section of the peripheral portion BD2 is approximately triangular, but is not limited thereto and may be, for example, a trapezoidal cross section.

[0043] However, as shown in Fig. 4, it is preferable that the adhesive BD, i.e., the fixing portion 100, be applied in an amount that does not reach the outer periphery of the pressure detection element 64 (that is, is positioned closer to the base 40 than the outer periphery). This makes it possible to make the pressure detection element 64 less susceptible to the effects of electric charge and stress.

[0044] In this embodiment, the presence of the fixing portion 100 around the periphery of the first substrate 62 prevents the liquid medium from reaching the gap between the bottom surface of the recess 40b and the first substrate 62, thereby suppressing swelling of the fixing portion 100 disposed between the first substrate 62 and the bottom surface of the recess 40b. This prevents the pressure detection device 60 from changing its posture, thereby preventing load from being applied to the terminals (bonding pads) of the pressure detection device 60 to which the bonding wires 80 and 82 are connected. Maintaining a constant gap between the inner circumferential surface 40d of the recess 40b and the first substrate 62 allows the fixing portion 100 to swell, canceling the load input to the first substrate 62. This prevents or suppresses change in the position of the pressure detection device 60 in the planar direction of the bottom surface of the recess 40b. When the peripheral portion BD2 of the fixed portion 100 is cut along a plane normal to the bottom surface of the recess 40b, it has a substantially triangular cross section. This prevents the liquid medium from penetrating between the bottom surface of the recess 40b and the first substrate 62, while reducing the amount of peripheral portion BD2 disposed around the first substrate 62. This reduces the load input to the first substrate 62 due to swelling of the fixed portion 100. The fixed portion 100 is configured so that it does not reach the second substrate 64, preventing the swelling of the fixed portion 100 from affecting the second substrate 64. As a result, changes in the posture of the second substrate 64 can be suppressed, thereby preventing a deterioration in the performance of the pressure sensor.

[0045] The present invention is not limited to the above-described embodiments, and any of the components of the embodiments may be modified or omitted within the scope of the present invention.

[0046] This specification includes the following disclosure of the invention: (First Aspect) A pressure sensor comprising: a base, a diaphragm provided on the base and forming a pressure-receiving chamber together with the base, a liquid medium filled in the pressure-receiving chamber, a fixing part provided on the base at a portion facing the pressure-receiving chamber, and a pressure detection device fixed to the fixing part and outputting a signal corresponding to the pressure in the pressure-receiving chamber, wherein the liquid medium is methylphenyl silicone oil or modified silicone oil, and the fixing part is any one of dimethyl silicone resin, vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin, or the liquid medium is dimethyl silicone oil, and the fixing part is any one of vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin.

[0047] (Second Aspect) The pressure sensor of the first aspect, characterized in that the pressure detection device has a first substrate on the base side and a second substrate arranged on the opposite side of the first substrate from the base, and a pressure detection circuit is mounted on the second substrate.

[0048] (Third Aspect) The pressure sensor according to the second aspect, wherein the first substrate is made of an insulating material or a semiconductor, and the second substrate is made of an insulating material or a semiconductor.

[0049] (Fourth Aspect) The pressure sensor according to the second or third aspect, wherein the first substrate is a glass substrate, and the second substrate is a silicon substrate.

[0050] (Fifth Aspect) A pressure sensor according to any one of the second to fourth aspects, characterized in that the base has a recess formed on the surface of the base facing the pressure-receiving chamber, the recess having a bottom surface and an inner peripheral surface, the fixing portion being provided in the recess, and the fixing portion comprising: a base portion disposed between the bottom surface of the base and the first substrate and in contact with the bottom surface and the first substrate, and a peripheral portion disposed between the inner peripheral surface of the recess and the outer peripheral surface of the first substrate and in contact with the inner peripheral surface and the outer peripheral surface.

[0051] (Sixth Aspect) The pressure sensor according to the fifth aspect, wherein the peripheral portion is located closer to the base than the second substrate.

[0052] (Seventh Aspect) The pressure sensor according to the fifth or sixth aspect, wherein the peripheral portion surrounds the entire outer periphery of the first substrate.

[0053] (8th Aspect) A pressure sensor according to any one of the 5th to 7th aspects, characterized in that when viewed in the normal direction of the bottom surface of the recess, the recess and the first substrate have similar shapes, the width of the gap between the inner peripheral surface of the recess and the outer peripheral surface of the first substrate is constant in the circumferential direction, and the inner peripheral surface is perpendicular to the bottom surface.

[0054] (9th Aspect) The pressure sensor according to any one of the 5th to 8th aspects, characterized in that the area of ​​a cross section of the peripheral portion perpendicular to the normal direction of the bottom surface of the recess decreases as the peripheral portion becomes farther away from the bottom surface of the recess.

[0055] (Tenth Aspect) A method for manufacturing a pressure sensor comprising: a base; a diaphragm provided on the base and forming a pressure-receiving chamber together with the base; a liquid medium filled in the pressure-receiving chamber; a fixing portion provided on the base facing the pressure-receiving chamber and formed by hardening an adhesive; and a pressure detection device fixed to the fixing portion and outputting a signal corresponding to the pressure of the pressure-receiving chamber, the method comprising: a first step of supplying any one of dimethyl silicone resin, vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive; a second step of arranging the pressure detection device on the adhesive; and a third step of supplying methyl phenyl silicone oil or modified silicone oil to the pressure-receiving chamber as the liquid medium, or a fourth step of supplying any one of vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive instead of the first step. a fifth step, instead of the third step, of supplying dimethyl silicone oil as the liquid medium to the pressure-receiving chamber.

[0056] REFERENCE SIGNS LIST 1 Pressure sensor 2 Pressure detection unit 10 Cover 20 Fluid inlet pipe 30 Mounting member 32 Fluid introduction chamber 40 Base 50 Diaphragm 52 Pressure receiving chamber 60 Pressure detection device 62 Pedestal 64 Pressure detection element 70 Terminal pin for ground 71 Terminal pin for input power supply 72 Terminal pin for sensor output 74 Hermetic seal 80, 81, 82 Bonding wire 90 Relay board 92 Connector 94 Lead wire 100 Fixing portion

Claims

1. A pressure sensor comprising: a base; a diaphragm provided on said base and forming a pressure-receiving chamber together with said base; a liquid medium filled in said pressure-receiving chamber; a fixing part provided on said base at a portion facing said pressure-receiving chamber; and a pressure detection device fixed to said fixing part and outputting a signal corresponding to the pressure in said pressure-receiving chamber, wherein said liquid medium is methylphenyl silicone oil or modified silicone oil, and said fixing part is any one of dimethyl silicone resin, vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin, or said liquid medium is dimethyl silicone oil, and said fixing part is any one of vinylmethyl silicone resin, methylphenyl silicone resin, fluorosilicone resin, and modified silicone resin.

2. The pressure sensor according to claim 1, characterized in that the pressure detection device has a first substrate on the base side and a second substrate arranged on the opposite side of the first substrate from the base, and a pressure detection circuit is mounted on the second substrate.

3. The pressure sensor according to claim 2, wherein the first substrate is made of an insulating material or a semiconductor, and the second substrate is made of an insulating material or a semiconductor.

4. The pressure sensor according to claim 3, wherein the first substrate is a glass substrate, and the second substrate is a silicon substrate.

5. A pressure sensor as claimed in any one of claims 2 to 4, characterized in that the base has a recess formed on the surface of the base facing the pressure-receiving chamber, the recess having a bottom surface and an inner peripheral surface, the fixing portion being provided in the recess, the fixing portion comprising: a base portion disposed between the bottom surface of the base and the first substrate and in contact with the bottom surface and the first substrate, and a peripheral portion disposed between the inner peripheral surface of the recess and the outer peripheral surface of the first substrate and in contact with the inner peripheral surface and the outer peripheral surface.

6. The pressure sensor according to claim 5, wherein the peripheral portion is located closer to the base than the second substrate.

7. The pressure sensor according to claim 5, wherein the peripheral portion surrounds the entire outer periphery of the first substrate.

8. The pressure sensor according to claim 5, characterized in that, when viewed in the normal direction of the bottom surface of the recess, the recess and the first substrate have similar shapes, the width of the gap between the inner peripheral surface of the recess and the outer peripheral surface of the first substrate is constant in the circumferential direction, and the inner peripheral surface is perpendicular to the bottom surface.

9. The pressure sensor according to claim 5, wherein the area of ​​a cross section of the peripheral portion perpendicular to the normal direction of the bottom surface of the recess decreases with increasing distance from the bottom surface of the recess.

10. A method for manufacturing a pressure sensor comprising: a base; a diaphragm provided on the base and forming a pressure-receiving chamber together with the base; a liquid medium filled in the pressure-receiving chamber; a fixing portion provided on the base facing the pressure-receiving chamber and formed by hardening an adhesive; and a pressure detection device fixed to the fixing portion and outputting a signal corresponding to the pressure of the pressure-receiving chamber, the method comprising: a first step of supplying any one of dimethyl silicone resin, vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive; a second step of placing the pressure detection device on the adhesive; and a third step of supplying methyl phenyl silicone oil or modified silicone oil to the pressure-receiving chamber as the liquid medium, or a fourth step of supplying any one of vinyl methyl silicone resin, methyl phenyl silicone resin, fluoro silicone resin, and modified silicone resin to the base as the adhesive instead of the first step. a fifth step, instead of the third step, of supplying dimethyl silicone oil as the liquid medium to the pressure-receiving chamber.

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