Pressure sensor device and method for manufacturing pressure sensor device

Abstract

To provide a pressure sensor device which suppresses generation of air bubbles, and can reduce the possibility of occurrence of defects such as wire breakage by growth of the air bubbles, and a method for manufacturing a pressure sensor device.SOLUTION: A pressure sensor device includes: a sensor unit 10 including a sensor chip 11 for converting a pressure into an electric signal by deformation of a diaphragm 11a and a member 12 supporting the sensor chip 11; and a resin case 1 storing the sensor unit 10. The bottom surface of the sensor unit 10 and the resin case 1 are fixed to each other by an adhesive 14, as for the bottom surface of the sensor unit 10 and the resin case 1, a central region S2 of the bottom surface of the sensor unit 10 is fixed to the resin case 1 by the adhesive 14, and a region S1 other than the central region S2 is a region 20 where there is the adhesive 14, but is not fixed to the resin case 1 by the adhesive 14.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to a pressure sensor device and a method for manufacturing the pressure sensor device.

Background Art

[0002] Conventionally, a pressure sensor device has been configured such that a pressure sensor unit is housed in a concave sensor mounting portion formed in a resin case body. The pressure sensor unit has a structure in which a pressure sensor chip is joined to a glass pedestal, and the glass pedestal is adhered to the bottom surface of the resin case (see, for example, Patent Document 1 below). Further, as a means for reducing the distortion of the pressure sensor unit caused by the difference in the linear expansion coefficients of the pressure sensor unit, the resin case, and the adhesive due to temperature changes and improving the accuracy, a method has been proposed in which the area fixed with the adhesive is made smaller than the diaphragm of the sensor chip (see, for example, Patent Document 2 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional pressure sensor device, there has been a problem that air bubbles are formed in the gap between the resin case and the bottom surface of the sensor unit, and the growth of the air bubbles compresses and cuts the wire portion connecting the sensor chip and the case. This disclosure aims to provide a pressure sensor device and a method for manufacturing the pressure sensor device that can suppress the generation of air bubbles and reduce the possibility of problems such as wire breakage due to the growth of air bubbles.

Means for Solving the Problems

[0005] In order to solve the above-described problems and achieve the object of the present disclosure, a pressure sensor device according to this disclosure has the following features. The pressure sensor device includes a sensor unit including a sensor chip that converts pressure into an electrical signal due to deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit. The bottom surface of the sensor unit and the resin case are fixed with an adhesive. The bottom surface of the sensor unit and the resin case are fixed to the resin case with the adhesive in the central region of the bottom surface of the sensor unit, and the region other than the central region is a region where there is adhesive but not fixed to the resin case with the adhesive.

[0006] According to the above-described disclosure, since the pressure sensor unit and the resin case are constrained only in a narrow region at the center of the region, the thermal stress due to the linear expansion difference between the pressure sensor unit and the resin case due to temperature change becomes small, and the deformation of the diaphragm of the pressure sensor unit becomes small. For this reason, deterioration of the accuracy of the sensor can be suppressed. Bubbles do not occur during gel application, and the possibility of problems such as wire breakage due to the growth of bubbles due to market pressure application or the like can be reduced.

Effect of the Invention

[0007] According to the pressure sensor device and the manufacturing method of the pressure sensor device according to the present disclosure, there is an effect that generation of bubbles can be suppressed and the possibility of problems such as wire breakage due to the growth of bubbles can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0009] <Summary of Embodiments of the Present Disclosure> In order to solve the above-described problems and achieve the object of the present disclosure, a pressure sensor device according to this disclosure has the following features. The pressure sensor device includes a sensor unit including a sensor chip that converts pressure into an electrical signal by deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit. The bottom surface of the sensor unit and the resin case are fixed with an adhesive, and the bottom surface of the sensor unit and the resin case are such that the central region of the bottom surface of the sensor unit is fixed to the resin case with the adhesive, and the region other than the central region is a region where there is the adhesive but is not fixed to the resin case with the adhesive.

[0010] According to the above disclosure, since the pressure sensor unit and the resin case are constrained only in a narrow area at the center of the region, the thermal stress due to the difference in linear expansion between the pressure sensor unit and the resin case caused by temperature changes is reduced, and the deformation of the diaphragm of the pressure sensor unit is reduced. Therefore, deterioration of the accuracy of the sensor can be suppressed. Bubbles do not occur during gel application, and the possibility of problems such as wire breakage due to the growth of bubbles caused by market pressure application or the like can be reduced.

[0011] In addition, in the pressure sensor device according to the present disclosure, in the above-mentioned disclosure, the region where the sensor unit is not fixed to the resin case with the adhesive is a region where a release agent is applied to the bottom surface of the sensor unit.

[0012] In addition, in the pressure sensor device according to the present disclosure, in the above-mentioned disclosure, the region where the sensor unit is not fixed to the resin case with the adhesive is a region where a release agent is applied to the bottom surface of the resin case.

[0013] In addition, in the pressure sensor device according to the present disclosure, in the above-mentioned disclosure, the release agent is characterized in that the main component is a fluororesin.

[0014] In addition, in the pressure sensor device according to the present disclosure, in the above-mentioned disclosure, the area of the region where the resin case and the sensor unit are fixed with the adhesive is 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm.

[0015] In order to solve the above-described problems and achieve the object of the present disclosure, a method for manufacturing a pressure sensor device according to this disclosure has the following features. A sensor unit including a sensor chip that converts pressure into an electrical signal by deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit. First, a first step of applying a release agent only to the peripheral portion of the bottom surface of the sensor unit is performed. Next, a second step of applying a predetermined amount of an adhesive to the bottom surface of the resin case or the bottom surface of the sensor unit is performed. Next, a third step of mounting the sensor unit at a predetermined position of the resin case and applying a predetermined temperature to cure the adhesive in a state where the adhesive exists throughout between the bottom surface of the sensor unit and the bottom surface of the resin case is performed. Next, a fourth step of connecting between the lead terminals of the sensor unit and the resin case with a bonding wire is performed. Next, a fifth step of injecting a protective gel into the resin case is performed. Next, a sixth step of exposing the resin case to a vacuum and defoaming the gel is performed. Next, a seventh step of applying a predetermined temperature to the resin case and curing the gel is performed.

[0016] In order to solve the above-described problems and achieve the object of the present disclosure, a method for manufacturing a pressure sensor device according to the present disclosure has the following features. A sensor unit including a sensor chip that converts pressure into an electrical signal due to deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit. A first step of applying a release agent only to the peripheral portion of a region facing the bottom surface of the sensor unit on the bottom surface of the resin case is performed. Next, a second step of applying a predetermined amount of an adhesive to the bottom surface of the resin case or the bottom surface of the sensor unit is performed. Next, a third step of mounting the sensor unit at a predetermined position of the resin case and applying a predetermined temperature in a state where the adhesive exists throughout between the bottom surface of the sensor unit and the bottom surface of the resin case to cure the adhesive is performed. Next, a fourth step of connecting between the lead terminals of the sensor unit and the resin case with a bonding wire is performed. Next, a fifth step of injecting a protective gel into the resin case is performed. Next, a sixth step of exposing the resin case to a vacuum to defoam the gel is performed. Next, a seventh step of applying a predetermined temperature to the resin case to cure the gel is performed.

[0017] Further, in the method for manufacturing a pressure sensor device according to the present disclosure, in the above-described disclosure, the region of the center portion of the bottom surface of the sensor unit where the release agent is not applied is in the range of 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm.

[0018] Further, in the method for manufacturing a pressure sensor device according to the present disclosure, in the above-described disclosure, the region of the center portion of the region of the bottom surface of the resin case facing the bottom surface of the sensor unit where the release agent is not applied is in the range of 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm.

[0019] <Findings underlying the present disclosure> First, the problems of the conventional semiconductor pressure sensor device will be described. The semiconductor pressure sensor device will be described with reference to the drawings. FIG. 11 is a cross-sectional view showing the structure of the conventional semiconductor pressure sensor device. The semiconductor pressure sensor device includes a pressure sensor unit 110 composed of a semiconductor pressure sensor chip 111 and a pedestal member 112, a resin case 101 formed of a thermoplastic resin such as PPS (Poly Phenylene Sulfide) and PBT (Poly Butylene Terephtalate), lead terminals 104, a gel 106, and an adhesive 114.

[0020] The semiconductor pressure sensor chip 111 has a diaphragm structure formed on a silicon substrate, and a plurality of semiconductor strain gauges made of a material having a piezoresistive effect are bridge-connected thereon. This semiconductor pressure sensor chip 111 is joined to the pedestal member 112 in a vacuum, and a vacuum reference chamber is formed in a portion surrounded by the diaphragm 111a and the pedestal member 112. In this pressure sensor unit 110, the resistance of the semiconductor strain gauge changes according to the pressure applied to the diaphragm 111a, and the amount of change is output as an electrical signal.

[0021] The pressure sensor unit 110 is fixed inside the resin case 101 with an adhesive 114. Also, the pressure sensor unit 110 is electrically connected to the lead terminals 104 via bonding wires 105. Further, the resin case 101 is filled with a protective gel 106 to protect the semiconductor pressure sensor chip 111 and the bonding wires 105 from the pressure medium.

[0022] The assembly of a semiconductor pressure sensor device with such a configuration generally involves applying an adhesive 114 to a resin case 101, mounting a pressure sensor unit 110 on the adhesive 114, and then heating to cure the adhesive 114. Since there is a difference in the linear expansion coefficient between the pressure sensor unit 110 made of silicon and glass and the resin case 101, when the adhesive 114 is cured by heating to temperature T, for example, at room temperature, an assembly stress is applied by the temperature difference from T. The stress caused by such a temperature change leads to distortion in the pressure sensor unit 110 and a decrease in the accuracy of the sensor output.

[0023] For this reason, in Patent Document 2, as a means to reduce the distortion of the pressure sensor unit 110 caused by the difference in the linear expansion coefficient of the pressure sensor unit 110, resin case 101, and adhesive 114 due to temperature change and improve the accuracy, a method has been proposed of making the area fixed by the adhesive 114 smaller than the diaphragm 111a of the semiconductor pressure sensor chip 111. FIG. 12 is a cross-sectional view showing the structure of a semiconductor pressure sensor device with a reduced area fixed by a conventional adhesive.

[0024] In this semiconductor pressure sensor device, by fixing only a narrow area at the center of the pressure sensor unit 110, the number of constrained parts is reduced, and an effect of suppressing the deformation of the pressure sensor unit 110 is obtained. As a result, since the deformation of the diaphragm 111a of the pressure sensor unit 110 due to temperature change as described above is suppressed, an effect of suppressing the deterioration of the accuracy of the sensor output can be expected.

[0025] However, in the configuration where only the narrow region at the center of the pressure sensor unit 110 is adhered as described above, a gap is formed between the resin case 101 and the bottom surface of the pressure sensor unit 110. When the protective gel 106 is applied with this gap present, there arises a problem that air bubbles 131 are formed in this gap portion. After the gel 106 is applied, the air bubbles 131 are removed by vacuum degassing before curing, but the air bubbles 131 formed deep inside the bottom surface of the pressure sensor unit 110 may remain even after degassing. Since the gel 106 permeates gas to a certain extent, the size of the air bubbles 131 formed on the bottom surface of the pressure sensor unit 110 may increase due to the application of market pressure or the like. When the size of the air bubbles 131 becomes larger than a certain level, there is a problem that the bonding wire 105 connecting the semiconductor pressure sensor chip 111 and the resin case 101 is compressed and the bonding wire 105 is cut off.

[0026] In order to solve the above problems, the present disclosure provides a pressure sensor device and a method for manufacturing a pressure sensor device that can suppress the generation of air bubbles and reduce the possibility of problems such as wire breakage due to the growth of air bubbles.

[0027] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the pressure sensor device and the method for manufacturing a pressure sensor device according to this disclosure will be described in detail. In the description of the following embodiments and the accompanying drawings, the same components are denoted by the same reference numerals, and overlapping descriptions are omitted.

[0028] (Embodiment) The structure of the semiconductor pressure sensor device according to the embodiment will be described. FIGS. 1 and 2 are cross-sectional views showing the structure of the semiconductor pressure sensor device according to the embodiment, and FIG. 3 is a plan view showing the layout of the semiconductor pressure sensor device of FIGS. 1 and 2 as viewed from above. The semiconductor pressure sensor device shown in FIGS. 1, 2, and 3 includes a resin case 1, lead terminals (lead frames) 4 for external connection, bonding wires 5, a protective gel 6, and a pressure sensor unit 10.

[0029] The resin case 1 is a housing container body for housing the pressure sensor unit 10, and has a concave sensor mounting portion 2 for housing the pressure sensor unit 10 therein. The resin case 1 is formed, for example, by integrally insert-molding a plurality of lead terminals 4 using a predetermined mold. One end of the lead terminal 4 is exposed inside the resin case 1, and the other end is exposed outside the resin case 1. FIG. 1 shows a case where the other end of the lead terminal 4 protrudes outside from the side surface of the resin case 1, but the arrangement of the lead terminals 4 can be variously changed.

[0030] The sensor mounting portion 2 is integrally molded with the resin case 1, for example. The sensor mounting portion 2 only needs to be sized to accommodate the pressure sensor unit 10, and its planar shape can be variously changed. FIG. 3 shows a case where the planar shape of the sensor mounting portion 2 is a substantially rectangular shape, but the planar shape of the sensor mounting portion 2 may be, for example, a substantially circular shape or a substantially elliptical shape. When the planar shape of the sensor mounting portion 2 is, for example, a substantially circular shape or a substantially elliptical shape, there are no corners where resin is difficult to flow into during the molding of the resin case 1, so molding defects of the resin case 1 can be suppressed.

[0031] The pressure sensor unit 10 is horizontally held with respect to the bottom surface of the sensor mounting portion 2 and is adhered to the bottom surface of the sensor mounting portion 2 with an adhesive 14 without contacting the side wall of the sensor mounting portion 2. The pressure sensor unit 10 includes a semiconductor pressure sensor chip 11 and a pedestal member 12. The pressure sensor unit 10 has a structure in which the semiconductor pressure sensor chip 11 is joined to one surface of the pedestal member 12, and the inner portion of the other surface of the pedestal member 12 is die-bonded (fixed) to the bottom surface 2a of the sensor mounting portion 2 via the adhesive 14. Further, the pressure sensor unit 10 is arranged away from the side wall of the sensor mounting portion 2. Note that the central side (the central side of the semiconductor pressure sensor chip 11 and the pedestal member 12) of the pressure sensor unit 10 is regarded as the inner side, and the outer peripheral side (the end side of the semiconductor pressure sensor chip 11 and the pedestal member 12) is regarded as the outer side.

[0032] The semiconductor pressure sensor chip 11 includes a diaphragm (pressure receiving part) 11a that is deflected by pressure, a resistance bridge composed of strain gauges (not shown), and an arithmetic circuit part (not shown) for amplifying and correcting the output of the resistance bridge, and is a silicon (Si) chip that converts the strain of the diaphragm 11a into an electrical signal. In FIGS. 1, 2, and 3, the illustration of the strain gauges is omitted. The semiconductor pressure sensor chip 11 is electrostatically bonded (anodic bonded), for example, to one surface of the pedestal member 12 so as to close the recess 11b formed in the portion where the diaphragm 11a is disposed with the pedestal member 12.

[0033] The diaphragm 11a is a portion thinned by a substantially columnar recess 11b provided, for example, at the center of the back surface of the semiconductor pressure sensor chip 11. The diaphragm 11a has, for example, a circular planar shape. In FIG. 3, the diaphragm 11a is indicated by a broken line, and r1 in FIG. 3 indicates the diameter of the diaphragm 11a. The thickness of the diaphragm 11a varies depending on the pressure range to be measured, but is, for example, about several tens of μm. The pedestal member 12 is made of, for example, heat-resistant glass. The inner portion of the other surface of the pedestal member 12 is die-bonded to the bottom surface 2a of the sensor mounting portion 2 via an adhesive 14. X1 in FIG. 3 indicates the length of one side of the other surface of the pedestal member 12 (the bottom surface of the sensor unit 10).

[0034] The adhesive 14 exists between the entire surface of the other surface of the pedestal member 12 and the bottom surface 2a of the sensor mounting portion 2, and the surface area of the adhesive 14 is substantially the same as the surface area of the other surface of the pedestal member 12. The surface area of the adhesive 14 is the area of the interface between the adhesive 14 and the other surface of the pedestal member 12.

[0035] The adhesive 14 is formed of, for example, a polymer material that does not contain free oil. Free oil is an additive for adjusting physical properties such as elastic modulus, penetration, and hardness. By forming the adhesive 14 using an adhesive that does not contain free oil, when the pressure sensor unit 10 is die-bonded to the bottom surface of the sensor mounting portion 2, the wetting spread of the adhesive 14 is suppressed, and the adhesive 14 can be disposed within a predetermined range.

[0036] Specifically, when the adhesive 14 is sandwiched between the bottom surface 2a of the sensor mounting portion 2 and the sensor unit 10, the wetting spread is suppressed by surface tension. For this reason, the viscosity of the adhesive 14 only needs to be high enough to suppress the wetting spread of the adhesive 14 within a predetermined time (for example, about 20 seconds) from when the adhesive 14 is applied to the substantially central portion of the bottom surface 2a of the sensor mounting portion 2 until the pressure sensor unit 10 is placed on the adhesive 14 and the adhesive 14 is sandwiched between the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2. More specifically, the viscosity of the adhesive 14 may be, for example, 5 Pa·s (Pascal second) or more at 25°C. The adhesive 14 may be, for example, an inexpensive silicone-based adhesive or a fluorine-based adhesive with high chemical resistance.

[0037] The adhesive 14 is brought into contact with the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2 so as to sandwich the adhesive 14 between the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2, and the pressure sensor unit 10 is housed inside the resin case 1 within a predetermined time. Then, by curing the adhesive 14 sandwiched between the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2, the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2 are die-bonded via the adhesive 14. By using the adhesive 14 having the above-described viscosity, the side surface of the adhesive 14 becomes substantially perpendicular to the other surface of the pedestal member 12, or is curved so as to protrude inward or outward.

[0038] The resistance bridge is a bridge circuit in which a plurality of strain gauges (semiconductor strain gauges) formed of a material having a piezoresistive effect (for example, a diffusion region formed in the diaphragm 11a by ion implantation or the like) are bridge-connected. The strain gauges (not shown) are arranged on the front surface side of the semiconductor pressure sensor chip 11. The arithmetic circuit portion is arranged, for example, in a portion of the semiconductor pressure sensor chip 11 other than the diaphragm 11a (that is, the outer peripheral portion surrounding the diaphragm 11a in the semiconductor pressure sensor chip 11).

[0039] The arithmetic circuit section does not have to be integrated with the semiconductor pressure sensor chip 11. In this case, the arithmetic circuit section is formed on another semiconductor chip (not shown) other than the semiconductor pressure sensor chip 11. The other semiconductor chip on which the arithmetic circuit section is arranged may be housed in the sensor mounting section 2 together with the semiconductor pressure sensor chip 11, or may be arranged outside the semiconductor pressure sensor device. In either case, the other semiconductor chip on which the arithmetic circuit section is arranged is electrically connected to the semiconductor pressure sensor chip 11. The electrode pads of the other semiconductor chip on which the arithmetic circuit section is arranged are electrically connected to the electrode pads 7 on the front surface of the semiconductor pressure sensor chip 11 by a plurality of lead terminals 4.

[0040] The electrode pads 7 on the front surface of the semiconductor pressure sensor chip 11 are electrically connected to the lead terminals 4 via bonding wires 5. The pressure sensor unit 10 (semiconductor pressure sensor chip 11), the portion of the lead terminals 4 exposed inside the resin case 1, and the bonding wires 5 are embedded in the gel 6 filled in the sensor mounting section 2 and are protected by the gel 6 from the adhesion of contaminants contained in the pressure medium to be measured.

[0041] The protective gel 6 is a pressure medium that transmits pressure to the pressure sensor unit 10. When the atmospheric pressure (1 atm) or stress applied to the gel 6 becomes higher than normal (when the displacement amount of the diaphragm 11a is zero), the diaphragm 11a is pushed into the pedestal member 12 side, so that the strain gauge is compressed and the resistance value of the strain gauge becomes higher. On the other hand, when the atmospheric pressure or stress applied to the gel 6 becomes lower than normal, the strain gauge is also pulled in a direction away from the pedestal member 12 together with the diaphragm 11a, and the resistance value of the strain gauge becomes lower.

[0042] The absolute value of the displacement amount of the height position of the pressure-received diaphragm 11a is, for example, about 20 nm to 30 nm. When the height position of the diaphragm 11a is displaced, the arithmetic circuit unit acquires the resistance value of the strain gauge corresponding to the displacement of the height position of the diaphragm 11a. Further, the arithmetic circuit unit calculates a voltage corresponding to the acquired resistance value of the strain gauge based on, for example, the temperature-corrected output characteristics of the semiconductor pressure sensor chip 11 obtained in advance, and outputs the calculation result to the outside as an electrical signal.

[0043] In the embodiment, an area of the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 that faces the bottom surface 10a of the pressure sensor unit 10 is defined as an adhesion area 1a on the resin case 1 side. Then, the bottom surface 10 of the pressure sensor unit 10 that faces the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 is defined as an adhesion area 10a on the pressure sensor unit 10 side. The resin case 1 and the pressure sensor unit 10 are fixed by an adhesive at the center area S2 of the area, and are not fixed by the adhesive in the peripheral area S1 of the area other than the center area S2. By performing a process that makes it difficult to adhere to the peripheral area S1 of the adhesion area 1a or the adhesion area 10a, a non - adherent area 20 is formed. In this way, the peripheral area S1 between the adhesion area 1a and the adhesion area 10a has a structure in which the adhesive 14 exists but is not adhered. FIG. 1 shows a form in which the non - adherent area 20 is formed in the adhesion area 10a of the pressure sensor unit 10, and FIG. 2 shows a form in which the non - adherent area 20 is formed in the adhesion area 1a on the resin case 1 side. Here, as a process for creating the non - adherent area 20, for example, commercially available release agents containing fluororesin, silicone, etc. as main components can be mentioned. A release agent is a chemical used to improve the mold release of products produced and manufactured by molding, and has a function of reducing the frictional force between substances. The area of the adhesion area 10a where the resin case 1 and the pressure sensor unit 10 are adhered by the adhesive 14 at the center area S2 of the area is, for example, 5% or more of the area of the adhesion area 1a (bottom surface) of the pressure sensor unit 10, and desirably 200% or less of the area of the diaphragm 11a. By setting it to 5% or more of the area of the adhesion area 1a (bottom surface) of the pressure sensor unit 10, the pressure sensor unit 10 can be surely fixed to the resin case, and by setting it to 200% or less of the area of the diaphragm 11a, fluctuations in the output voltage over time from the initial stage can be suppressed.

[0044] With the above structure, since the pressure sensor unit 10 and the resin case 1 are constrained only in the narrow region of the center part S2 of the region, the thermal stress due to the difference in linear expansion between the pressure sensor unit 10 and the resin case 1 caused by temperature change is reduced. As a result, the deformation of the diaphragm 11a of the pressure sensor unit 10 is reduced. Therefore, it is possible to suppress the deterioration of the accuracy of the pressure sensor. On the other hand, since the adhesive 14 exists throughout the area between the adhesive area 1a of the concave part of the sensor mounting part 2 of the resin case 1 and the adhesive area 10a of the pressure sensor unit 10, no bubbles are generated between the adhesive area 1a and the adhesive area 10a when the gel 6 is applied. Since the generation of bubbles between the adhesive area 1a and the adhesive area 10a is suppressed, it is possible to reduce the possibility of problems such as breakage of the bonding wire 5 due to the growth of bubbles caused by the application of market pressure or the like. As a result, it is possible to achieve both reduction of thermal stress by restraining only the center part S1 of the region and suppression of bubble generation by not creating a gap.

[0045] (Manufacturing method of semiconductor pressure sensor device according to embodiment) Next, the manufacturing method of the semiconductor pressure sensor device according to the embodiment will be described in Examples 1 and 2. By assembling the pressure sensor unit 10 and the resin case 1 as in Examples 1 and 2, it is possible to form the region S1 other than the center of the pressure sensor unit 10 into a structure in which there is the adhesive 14 but it is not adhered.

[0046] (Example 1) Example 1 is an example of the semiconductor pressure sensor device shown in FIG. 1. FIGS. 4 to 7 are cross-sectional views schematically showing the state during the manufacture of the semiconductor pressure sensor device of Example 1. In Example 1, first, as shown in FIG. 4, a release agent 15 is applied to the bottom surface of the pressure sensor unit 10. At this time, the release agent 15 is applied only to the peripheral part S1 of the region, and the release agent 15 is not applied to the circular region with a diameter of 1 mm from the center of the bottom surface of the pressure sensor unit 10 by means of a mask (first step). The region where the release agent 15 is applied becomes the difficult-to-adhere region 20 in FIG. 1.

[0047] Next, as shown in FIG. 5, an adhesive 14 is applied to the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 on which the pressure sensor unit 10 is mounted in an area larger than the bottom surface size of the pressure sensor unit 10 (second step). Next, as shown in FIG. 6, the pressure sensor unit 10 is mounted at a predetermined position on the resin case 1 to which the adhesive 14 has been applied, and a predetermined temperature is applied to cure the adhesive 14 (third step).

[0048] The area fixed by the adhesive 14 between the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 is 0.79 mm 2 This is the case. Although the case where the adhesive 14 is applied to the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 in an area larger than the bottom surface size of the pressure sensor unit 10 has been described, the adhesive 14 may be applied to the bottom surface of the pressure sensor unit 10.

[0049] Next, as shown in FIG. 7, after curing the adhesive 13, the pressure sensor unit 10 and the lead terminals 4 of the resin case 1 are connected with bonding wires 5 (fourth step). Next, a protective gel 6 is injected into the resin case 1 on which the pressure sensor unit 10 is mounted (fifth step). Next, the resin case 1 on which the pressure sensor unit 10 is mounted and into which the protective gel 6 has been injected is exposed to a vacuum of 500 Pa to defoam the gel 6 (sixth step). After defoaming, a predetermined temperature is applied to cure the gel 6 (seventh step). Thus, the semiconductor pressure sensor device shown in FIG. 1 is completed.

[0050] (Example 2) Example 2 is an example of the semiconductor pressure sensor device shown in FIG. 2. FIGS. 8 to 10 are cross-sectional views schematically showing the state during the manufacture of the semiconductor pressure sensor device of Example 2. In Example 2, first, as shown in FIG. 8, a release agent 15 is applied to the adhesive region 1a on the resin case side of the resin case 1 on which the pressure sensor unit 10 is mounted. At this time, the release agent 15 is applied only to the peripheral portion S1 of the region, and a circular region with a diameter of 1 mm from the center is masked so that the release agent 15 is not applied (first step). The region to which the release agent 15 is applied becomes the difficult-to-bond region 20 in FIG. 2.

[0051] Next, as shown in FIG. 9, an adhesive 14 is applied to the adhesion region 10a on the bottom surface of the pressure sensor unit 10 within a predetermined range (second step). Next, as shown in FIG. 10, the pressure sensor unit 10 is mounted at a predetermined position on the resin case 1 to which the adhesive 14 has been applied, and a predetermined temperature is applied to cure the adhesive 14 (third step). After this, by performing the same steps as in Example 1, the semiconductor pressure sensor device shown in FIG. 2 is completed.

[0052] The area fixed by the adhesive 14 between the pressure sensor unit 10 and the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 is 0.79 mm 2 This is the case. Although the application of the adhesive 14 to the pressure sensor unit 10 has been described, the adhesive 14 may be applied to an area on the bottom surface 2a of the sensor mounting portion 2 of the resin case 1 that is larger than the bottom surface size of the pressure sensor unit 10.

[0053] In the above Examples 1 and 2, the bottom surface of the pressure sensor unit 10 is square, the length x1 of one side is 3 mm, and the diameter r1 of the diaphragm 11a is 1.3 mm. Therefore, the area fixed by the adhesive 14 between the concave bottom surface of the sensor mounting portion 2 of the resin case 1 and the pressure sensor unit 10 is 0.45 mm, which is 5% of the area of the bottom surface of the pressure sensor unit 10, 9.0 mm 2 That is, it is 0.45 mm 2 As described above, it is desirable that the area of the diaphragm 11a is 2.65 mm, which is 200% of 1.327 mm 2 That is, it is 2.65 mm 2 or less.

[0054] As described above, according to the embodiment, the semiconductor pressure sensor device forms a difficult-to-bond region on the bonding region (bottom surface) of the pressure sensor unit. As a result, since the pressure sensor unit and the resin case are constrained only in a narrow region at the center of the region, the thermal stress due to the linear expansion difference between the pressure sensor unit and the resin case caused by temperature changes is reduced, and the deformation of the diaphragm of the pressure sensor unit is reduced. Therefore, deterioration of the accuracy of the pressure sensor can be suppressed. Further, since the adhesive is present over the entire bottom surface of the pressure sensor unit, bubbles are not generated during gel application, and the possibility of problems such as wire breakage due to the growth of bubbles caused by market pressure application or the like can be reduced.

[0055] In the above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, the dimensions of each part, the constituent materials of the resin case, lead terminals, bonding wires, gel, adhesive, etc. can be variously modified according to the required specifications and the like.

Industrial Applicability

[0056] As described above, the pressure sensor device and the method for manufacturing the pressure sensor device according to the present disclosure are useful for a semiconductor pressure sensor device in which a sensor unit is mounted on a resin case via an adhesive.

Explanation of Reference Numerals

[0057] 1, 101 Resin case 1a Adhesive region on the resin case side 2 Sensor mounting portion 2a Bottom surface of the sensor mounting portion 4, 104 Lead terminals 5, 105 Bonding wires 6, 106 Gel 10, 110 Pressure sensor unit 10a Adhesive region of the pressure sensor unit 11, 111 Semiconductor pressure sensor chip 11a, 111a Diaphragm 11b Concave portion of the semiconductor pressure sensor chip 12, 112 pedestal members 14, 114 adhesives 15 release agent 20 difficult-to-bond regions 131 bubbles Peripheral part of region S1 Central part of region S2

Claims

1. A pressure sensor device comprising a sensor chip that converts pressure into an electrical signal by deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit, wherein the bottom surface of the sensor unit and the resin case are fixed with an adhesive, the bottom surface of the sensor unit and the resin case are such that the central region of the bottom surface of the sensor unit is fixed to the resin case with the adhesive, and the region other than the central region is a region where there is adhesive but not fixed to the resin case with the adhesive.

2. The pressure sensor device according to claim 1, wherein the region where the sensor unit is not fixed to the resin case with the adhesive is a region where a release agent is applied to the bottom surface of the sensor unit.

3. The pressure sensor device according to claim 1, wherein the region where the sensor unit is not fixed to the resin case with the adhesive is a region where a release agent is applied to the bottom surface of the resin case.

4. The pressure sensor device according to claim 2 or 3, wherein the release agent has a main component of a fluororesin.

5. The area of the region where the resin case and the sensor unit are fixed with the adhesive is 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm.

6. A method for manufacturing a pressure sensor device comprising a sensor chip that converts pressure into an electrical signal by deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit, the method comprising: a first step of applying a release agent only to the peripheral portion of the bottom surface of the sensor unit; a second step of applying a predetermined amount of adhesive to the bottom surface of the resin case or the bottom surface of the sensor unit; a third step of mounting the sensor unit at a predetermined position of the resin case and applying a predetermined temperature in a state where the adhesive exists throughout the space between the bottom surface of the sensor unit and the bottom surface of the resin case to cure the adhesive; a fourth step of connecting the lead terminals between the sensor unit and the resin case with a bonding wire; a fifth step of injecting a protective gel into the resin case; a sixth step of exposing the resin case to a vacuum to defoam the gel. A seventh step of applying a predetermined temperature to the resin case to cure the gel; A method for manufacturing a pressure sensor device, characterized by including the above steps. **Claim 7** A method for manufacturing a pressure sensor device, comprising a sensor unit including a sensor chip that converts pressure into an electrical signal due to deformation of a diaphragm and a member that supports the sensor chip, and a resin case that houses the sensor unit, A first step of applying a release agent only to the peripheral portion of the region of the bottom surface of the resin case that faces the bottom surface of the sensor unit; A second step of applying a predetermined amount of adhesive to the bottom surface of the resin case or the bottom surface of the sensor unit; A third step of mounting the sensor unit at a predetermined position of the resin case, and applying a predetermined temperature in a state where the adhesive exists throughout the space between the bottom surface of the sensor unit and the bottom surface of the resin case to cure the adhesive; A fourth step of connecting the sensor unit and the lead terminals of the resin case with bonding wires; A fifth step of injecting a protective gel into the resin case; A sixth step of exposing the resin case to a vacuum to defoam the gel; A seventh step of applying a predetermined temperature to the resin case to cure the gel; A method for manufacturing a pressure sensor device, characterized by including the above steps. **Claim 8** The method for manufacturing a pressure sensor device according to claim 6, characterized in that the area of the central portion of the bottom surface of the sensor unit where the release agent is not applied is in the range of 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm. **Claim 9** The method for manufacturing a pressure sensor device according to claim 7, characterized in that the area of the central portion of the region of the bottom surface of the resin case that faces the bottom surface of the sensor unit and where the release agent is not applied is in the range of 5% or more of the area of the bottom surface of the sensor unit facing the bottom surface of the resin case and 200% or less of the area of the diaphragm.

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