Fluid sensor and method for manufacturing the same

Abstract

To facilitate management of a resin filling amount, reduce variation in flatness of a resin, and suppress lowering of measuring accuracy of flow speed by a fluid sensor.SOLUTION: A fluid sensor includes: a sensor chip which is mounted on a substrate and detects a fluid flowing on the surface; a first housing which is arranged on the substrate so as to surround the periphery of the sensor chip; a one-pack type resin which is made to fill a recess between the sensor chip and the first housing and contains a filler; a second housing which is arranged on the first housing; and a flow channel of a fluid which is provided between the first housing and the second housing and flows on the surface of the sensor chip.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluid sensor and a method for manufacturing a fluid sensor. [Background technology]

[0002] In a known technique for measuring the flow velocity of gas, resistor elements that function as temperature-sensing elements are placed on both sides of a heater, and the flow velocity is measured based on the difference in the resistance values ​​of the resistor elements, which change according to the airflow. This type of fluid sensor suppresses the generation of turbulence in the airflow flowing from outside the fluid sensor onto the sensor chip by filling a recess between the periphery of the sensor chip mounted on a substrate and the housing with resin in accordance with the height of the sensor chip (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-54528 Summary of the Invention [Problem to be solved by the invention]

[0004] If the resin filling does not sufficiently fill the recess, leaving the substrate exposed, or if the resin does not adhere sufficiently to the sidewall of the sensor chip or the sidewall of the housing, moisture may penetrate the substrate and corrode the terminals on the substrate. For example, using a two-component resin with a lower viscosity than a one-component resin can improve the resin's penetration. However, two-component resins increase in viscosity over time, making it difficult to control the amount of resin filled and reducing workability. Furthermore, if uneven resin filling creates concave or convex steps around the sensor chip, the accuracy of flow rate measurement by the fluid sensor may be reduced.

[0005] The disclosed technology aims to simplify management of the amount of resin filled, reduce variations in the flatness of the resin, and suppress a decrease in the accuracy of measuring flow velocity by a fluid sensor. [Means for solving the problem]

[0006] In order to solve the above technical problems, a fluid sensor according to one aspect of the present invention includes a sensor chip mounted on a substrate and detecting a fluid flowing on a surface thereof, a first housing arranged on the substrate and surrounding the sensor chip, a one-component resin containing a filler that is filled in a recess between the sensor chip and the first housing, a second housing arranged on the first housing, and a flow path for a fluid flowing on the surface of the sensor chip that is provided between the first housing and the second housing. The resin has a viscosity of 4 Pa·s and contains 55% to 65% (volume %) of filler having a particle size of 1 to 4 μm. . [Effects of the Invention]

[0007] The amount of resin filled can be easily controlled, which reduces variations in the flatness of the resin and suppresses a decrease in the accuracy of measuring the flow rate by the fluid sensor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a fluid sensor according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of the sensor chip of FIG. [Figure 3] 2A to 2C are diagrams illustrating an example of a method for manufacturing the fluid sensor of FIG. 1. [Figure 4] 4 is a diagram showing a continuation of the manufacturing method shown in FIG. 3. [Figure 5] 2A and 2B are diagrams showing examples of the surface shape of the resin filled in the recess in FIG. 1 after it has hardened, and an air flow passing over the resin. [Figure 6] 2 is a diagram showing an example of the composition of a resin filled in the recess in FIG. 1. FIG. [Figure 7] FIG. 2 is a flow chart showing an example of a method for manufacturing the fluid sensor of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[0010] (Structure of fluid sensor) FIG. 1 is a diagram illustrating an example of a fluid sensor according to an embodiment of the present invention. In the following description, the side of the arrowhead indicating the Z direction will also be referred to as the upper side, and the side opposite the arrowhead will also be referred to as the lower side. The fluid sensor 100 shown in FIG. 1 includes a sensor chip 110, a substrate 120, a lower housing 130, and an upper housing 140. Although not particularly limited, the fluid sensor 100 may be installed outdoors as an anemometer, or may be installed indoors, such as in a clean room, to detect wind movement indoors. The lower housing 130 is an example of a first housing, and the upper housing 140 is an example of a second housing.

[0011] The sensor chip 110 is mounted, for example, approximately at the center of a rectangular substrate 120, and detects the wind speed and direction of a fluid (e.g., air) flowing into the fluid sensor 100. The sensor chip 110 is electrically connected to the substrate 120 via bonding wires 121. An example of the sensor chip 110 is shown in FIG. 2.

[0012] The lower housing 130 has a cylindrical outer frame 131 and a ring-shaped protrusion 132 that protrudes inward from the upper end of the outer frame 131. For example, the thickness of the protrusion 132 is designed to be the same as the thickness of the sensor chip 110.

[0013] Upper housing 140 has a disk-shaped lid portion 141, multiple support posts 142, and thick portion 143. Lid portion 141 has an outer diameter that is approximately the same as the outer diameter of outer frame 131 of lower housing 130. Multiple support posts 142 have, for example, a circular cross section, and are provided at equal intervals around the periphery of the lower surface of lid portion 141. Thick portion 143 is provided in the center of lid portion 141 facing sensor chip 110, and has a truncated cone shape.

[0014] The lower end of each support 142 is bonded to the upper end of outer frame 131 via resin 201, thereby fixing upper housing 140 to lower housing 130. Furthermore, lid portion 141 is supported by outer frame 131 by multiple support columns 142, thereby forming a fluid flow path 150 in the space between lid portion 141 and protrusion 132.

[0015] 1, the flow path 150 is formed all around the sensor chip 110 (in the X and Y directions), so the sensor chip 110 can detect the wind speed regardless of the wind direction of the fluid. In addition, by using the thick portion 143 to make the flow path on the sensor chip 110 narrower than the flow path in the area where the support 142 is arranged, the wind speed detection sensitivity of the sensor chip 110 can be increased.

[0016] The substrate 120 is bonded to the underside of the protruding portion 132 by resin 202 arranged around the periphery of the substrate 120, with the outer periphery of the upper surface of the substrate 120 in contact with the underside of the protruding portion 132. A plurality of electronic components 161, such as resistors, capacitors, and inductors, are mounted on the underside of the substrate 120. A plurality of pin-shaped external terminals 162 are fixed to the outer periphery of the underside of the substrate 120. For example, the plurality of external terminals 162 are soldered to through-holes or the like in a main substrate (not shown) on which the fluid sensor 100 is mounted.

[0017] The central portion of the substrate 120 has a through-hole 120a that penetrates to the space below the sensor chip 110. The through-hole 120a can prevent the pressure in the space below the sensor chip 110 from increasing due to heat (for example, heat generated when an adhesive is thermally cured) generated when the sensor chip 110 is mounted on the substrate 120. As a result, the sensor chip 110 can be prevented from being attached at an angle to the substrate 120.

[0018] An annular recess 170 surrounded by the inner wall of annular protrusion 132 of lower housing 130, the outer periphery of sensor chip 110, and the upper surface of substrate 120 is filled with resin 203. The upper surfaces of protrusion 132, sensor chip 110, and resin 203 are covered with protective film 180 that has waterproof and moisture-proof properties and is formed by applying, for example, a fluorine-based water-repellent coating agent.

[0019] The protective film 180 can prevent moisture from penetrating into the sensor chip 110, the interface between the sensor chip 110 and the resin 203, and the interface between the protrusion 132 and the resin 203. This can prevent corrosion of the connection between the pad provided on the sensor chip 110 and the bonding wire 121, for example.

[0020] Note that the distance between the inner wall of lower housing 130 and sensor chip 110 (corresponding to the width of recess 170) is preferably about twice the height (chip thickness) of sensor chip 110 or less in order to reduce depressions in the surface of resin 203. Also, the width of recess 170 is preferably about twice the chip thickness. This ensures that even if one or both of the mounting position of sensor chip 110 on substrate 120 and the bonding position of lower housing 130 on substrate 120 are misaligned, a space can be secured in recess 170 that allows bonding wire 121 to be reliably connected to the terminal on substrate 120.

[0021] In addition, in order to give the bonding wire 121 the desired curved shape and reliably connect it to the terminal on the substrate 120, it is preferable that the distance between the pad on the sensor chip 110 and the terminal on the substrate 120 in a planar view (as viewed from the Z direction) be set to approximately the height of the sensor chip 110.

[0022] (Sensor chip structure) Fig. 2 is a diagram showing an example of the sensor chip 110 of Fig. 1. Fig. 2(A) shows a plan view of the sensor chip 110, and Fig. 2(B) shows a cross-sectional view taken along line A-A' in Fig. 2(A). For example, the sensor chip 110 is formed using semiconductor manufacturing technology.

[0023] The sensor chip 110 has a heater resistor Rh that functions as a heater and temperature-sensing elements Ru (Ru(1), Ru(2)), Rd (Rd(1), Rd(2)). For example, the heater resistor Rh is made of platinum (Pt), nichrome (NiCr), molybdenum silicide (MoSi2), tungsten silicide (WSi2), polysilicon, or the like. For example, the temperature-sensing elements Ru and Rd are resistor elements having a vanadium oxide film whose resistance value changes with temperature.

[0024] For example, the size and thickness of the vanadium oxide films forming the temperature sensitive elements Ru and Rd are equal, and the resistance values ​​of the temperature sensitive elements Ru and Rd are equal. The resistance values ​​of the temperature sensitive elements Ru and Rd change in response to changes in the ambient temperature due to heat generation by the heater resistor Rh, etc., and the current flowing through the temperature sensitive elements Ru and Rd changes.

[0025] For example, the heater resistor Rh is provided in the center of the sensor chip 110, which is square in plan view (top view). The temperature sensitive elements Ru(1) and Rd(1) are provided on both sides of the sensor chip 110 in the X direction. The temperature sensitive elements Ru(2) and Rd(2) are provided on both sides of the sensor chip 110 in the Y direction. In other words, the sensor chip 110 has two pairs of temperature sensitive elements, in which the arrangement directions of the temperature sensitive elements Ru(1) and Rd(1) and the arrangement directions of the temperature sensitive elements Ru(2) and Rd(2) are different.

[0026] The distances between each of the temperature sensing elements Ru(1), Rd(1), Ru(2), and Rd(2) and the heater resistor Rh are the same. Also, a temperature sensor TSNS formed by meandering a thin and long wire is provided on the sensor chip 110.

[0027] The sensor chip 110 has a semiconductor substrate SUB provided on the periphery of the sensor chip 110 in a plan view, and a membrane MEMB (thin film) provided on the semiconductor substrate SUB. For example, the semiconductor substrate SUB is a silicone substrate or an SOI (Silicon On Insulator) substrate. The membrane MEMB may have a multilayer wiring structure. In the center of the sensor chip 110, a space SP is provided on the back surface of the membrane MEMB facing the semiconductor substrate SUB. The heater resistor Rh and the temperature-sensing elements Ru and Rd are disposed on the membrane MEMB facing the space SP. A protective film PASF is provided on the membrane MEMB to cover the heater resistor Rh and the temperature-sensing elements Ru and Rd. Pads PAD exposed from the protective film PASF are provided on the protective film PASF.

[0028] The heater resistor Rh has a square shape with a meandering, elongated wiring. This allows the relative positional relationship between the thermosensitive elements Ru(1), Rd(1), Ru(2), and Rd(2) and the heater resistor Rh to be the same. As a result, a control unit such as a CPU (Central Processing Unit) mounted on the main board together with the sensor chip 110 can calculate the wind speed over the heater resistor Rh for each pair of thermosensitive elements Ru and Rd based on the change in resistance value.

[0029] For example, the control unit can calculate the wind speed in the X direction based on the change in the resistance values ​​of the thermosensitive elements Ru(1) and Rd(1), and calculate the wind speed in the Y direction based on the change in the resistance values ​​of the thermosensitive elements Ru(2) and Rd(2). Furthermore, the control unit can calculate the direction of the airflow (wind direction) from the two wind velocities calculated based on the change in the resistance values ​​of the two thermosensitive element pairs Ru and Rd.

[0030] Both ends of each of the heater resistor Rh, the thermosensitive elements Ru(1), Rd(1), Ru(2), Rd(2), and the temperature sensor TSNS are connected to pads PAD provided on the outer periphery of the sensor chip 110 via wiring W. As shown in FIG. 1, each pad PAD is connected to a terminal provided on the substrate 120 via bonding wire 121, and is further connected to a main substrate (not shown) via an external terminal 162.

[0031] The two wires that are not connected to the pads PD are dummy wires DMY. By providing the dummy wires DMY, the layout of the wires around the heater resistor Rh and the temperature sensitive elements Ru and Rd can be made symmetrical. This makes it possible to suppress variations in the shapes of the temperature sensitive elements Ru and Rd during the semiconductor manufacturing process of the sensor chip 110, and to suppress deviations in the electrical characteristics of the temperature sensitive elements Ru and Rd.

[0032] (Method of manufacturing a fluid sensor) 3 and 4 are diagrams showing an example of a manufacturing method for the fluid sensor 100 of Fig. 1. For example, first, the sensor chip 110, electronic components 161, and external terminals 162 are mounted on the substrate 120. Next, the pads PAD of the sensor chip 110 and the terminals 120b of the substrate 120 are connected by bonding wires 121, thereby forming the sensor main body 101 shown in Fig. 3(A). Then, the lower housing 130 is placed on the substrate 120, and the protrusion 132 is disposed on the upper surface of the substrate 120.

[0033] 3(B), the outer periphery of substrate 120 and protruding portion 132 are bonded with resin 202. As a result, sensor main body 101 is fixed to lower housing 130 with the upper surface of substrate 120 in close contact with the lower surface of protruding portion 132. Then, an annular recess 170 is formed that is surrounded by the inner wall of protruding portion 132, the outer periphery of sensor chip 110, and the upper surface of substrate 120.

[0034] Next, as shown in FIG. 4(A), the recess 170 is filled with resin 203. For example, the resin 203 is an epoxy resin containing a predetermined amount of filler 203a having a predetermined range of particle size. For example, the filler 203a is glass, and the epoxy resin is a one-component type. The type of resin 203 is described in FIG. 6. The resin 203 is filled by pouring the heated resin 203 into the recess 170 while the sensor main body 101 and the lower housing 130 are in a warmed state.

[0035] By using an epoxy resin for the resin 203, moisture resistance and waterproofing can be ensured compared to using a silicone resin, and corrosion of the terminals on the substrate 120 can be suppressed. As a result, a fluid sensor 100 suitable for outdoor environments can be formed. Furthermore, by mixing a filler into the resin 203, it is possible to improve the wettability (the spread of the resin) even with a one-component epoxy resin, which has a higher viscosity than a two-component epoxy resin. Furthermore, by mixing a filler into the resin 203, it is possible to reduce the amount of shrinkage of the resin 203 when it hardens. The wettability of the resin 203 is explained in FIG. 6.

[0036] Furthermore, by using epoxy resin for resin 203, the heat curing temperature can be lowered compared to when silicone resin is used, and the temperature applied to sensor chip 110, substrate 120, and lower housing 130 can be lowered when resin 203 is heat cured. This allows for a wider range of options for the material of substrate 120 or lower housing 130, for example.

[0037] For example, resin 203 is filled up to near the upper surface of recess 170 so as not to rise above the upper surface of recess 170. Thereafter, sensor main body 101 and lower housing 130 are heated up to the hardening temperature of resin 203, and resin 203 is hardened.

[0038] By making the upper surface of resin 203 flat and aligned with the upper surface of sensor chip 110 and the upper surface of protrusion 132, it is possible to prevent the airflow that passes through the upper surface of resin 203 and flows into sensor chip 110 from being disturbed by the upper surface of resin 203. This makes it possible to prevent a decrease in the accuracy of measuring the flow velocity by fluid sensor 100.

[0039] Next, a water-repellent coating agent is applied to the upper surfaces of the sensor chip 110, the protrusion 132, and the resin 203. For example, the water-repellent coating agent is dropped onto the sensor chip 110, and is therefore also applied to the bonding wires 121 exposed above the recesses 170. Then, the water-repellent coating agent is dried by a heat treatment, and the protective film 180 is formed.

[0040] 4(B), resin 201 is applied at intervals to the upper surface of outer frame 131 of lower housing 130. Next, upper housing 140 is placed on lower housing 130 with supports 142 of upper housing 140 aligned with resin 201 applied to outer frame 131 of lower housing 130. Then, the lower ends of each support 142 are bonded to the upper end of outer frame 131 via resin 201, completing fluid sensor 100 shown in FIG.

[0041] (Relationship between resin filling amount and flatness) 5 is a diagram showing an example of the surface shape of the resin 203 filled in the recess 170 of FIG. 1 after it has hardened, and an example of an airflow passing over the resin 203. For example, when the filling amount of the resin 203 is 80% or more and 100% or less of the volume of the recess 170, the position of the surface of the resin 203 is approximately the same as or slightly lower than the upper surfaces of the protrusion 132 and the sensor chip 110. In other words, it is possible to ensure flatness between the surface of the resin 203 and the upper surfaces of the protrusion 132 and the sensor chip 110. In this case, the airflow AF passing over the resin 203 toward the sensor chip 110 flows straight toward the sensor chip 110. As a result, the speed of the airflow flowing into the fluid sensor 100 can be detected accurately by the sensor chip 110.

[0042] On the other hand, if the amount of resin 203 filled after curing is small, the surface of resin 203 will be lower than the upper surface of protrusion 132 and the upper surface of sensor chip 110, creating a concave step. In this case, the airflow AF flowing above sensor chip 110 will descend along the step as it passes over resin 203, and then ascend, moving away from sensor chip 110. Alternatively, the airflow AF flowing above sensor chip 110 will generate a vortex above resin 203. As a result, the flow velocity of the airflow passing through sensor chip 110 will differ from the velocity of the airflow flowing into fluid sensor 100, and the accuracy of flow velocity detection by sensor chip 110 will decrease.

[0043] Furthermore, if the amount of resin 203 filled after hardening is large and exceeds 100% of the volume of recess 170, the surface of resin 203 will be higher than the upper surface of protrusion 132 and the upper surface of sensor chip 110, creating a convex step. In this case, airflow AF heading toward sensor chip 110 rises along the step as it passes over resin 203, and moves away from sensor chip 110. As a result, the flow velocity of the airflow passing through sensor chip 110 differs from the velocity of the airflow flowing into fluid sensor 100, and the accuracy of flow velocity detection by sensor chip 110 decreases.

[0044] (Evaluation of wettability and workability due to differences in resins) Fig. 6 is a diagram showing examples of the composition of the resin 203 filled in the recess 170 in Fig. 1. For example, the inventors produced prototype fluid sensors 100 in which four types of resin 203 were filled in the recess 170, and evaluated the wettability and workability.

[0045] The resin 203 of specification A is a one-component epoxy resin (viscosity 4 Pa·s at room temperature) mixed with 55% to 65% (volume %) of filler with a particle size of 1 to 4 μm, and both the wettability and workability were good. Note that, as shown in Figure 4(A), the filler includes fillers with various particle sizes within the specification range.

[0046] Here, good wettability means that the resin 203 fills every corner of the recess 170 without any gaps. Even with a one-component epoxy resin, which has a higher viscosity than a two-component epoxy resin, wettability can be improved by mixing a filler of a predetermined particle size into the epoxy resin at a predetermined ratio. This allows the resin 203 to fill every corner of the recess 170 regardless of the skill of the worker, improving workability. As a result, the frequency of repairs that occur when the resin 203 does not fill the recess 170 sufficiently can be reduced. Because workability is improved and the frequency of repairs is reduced, the manufacturing cost of the fluid sensor 100 can be reduced.

[0047] Furthermore, by mixing a filler into the epoxy resin, the amount of shrinkage of the epoxy resin during thermal curing can be reduced. This allows the position of the surface of the resin 203 after filling the recess 170 with the resin 203 to be approximately the same as the position of the surface of the resin 203 after thermal curing. Therefore, it is possible to suppress a decrease in the measurement accuracy of the flow velocity of the fluid sensor 100 due to depressions in the resin 203 caused by thermal curing.

[0048] Furthermore, since the resin 203 can be made to flow around every corner of the recess 170, it is possible to prevent moisture and the like from penetrating the bottom surface of the recess 170. As a result, even if the protective film 180 is not formed, for example, it is possible to prevent the terminals on the substrate 120 from corroding and the bonding wires 121 from peeling off from the terminals. This makes it possible to prevent a decrease in the reliability of the fluid sensor 100.

[0049] Furthermore, since one-component epoxy resin has a more appropriate viscosity than two-component epoxy resin, for example, when filling recess 170 with resin 203, it is possible to prevent resin 203 from splashing out of recess 170. As a result, it is possible to fill recess 170 with an appropriate amount of resin 203 more easily than with two-component epoxy resin.

[0050] Resin 203 of specification B is a one-component epoxy resin (viscosity 10 Pa·s) mixed with 35% to 45% (volume %) of filler with a particle size of 20 to 50 μm, and both wettability and workability were good.

[0051] Resin 203 of specification C is a one-component epoxy resin (viscosity 25 Pa·s) mixed with 35% to 50% (volume %) of filler with a particle size of 20 to 50 μm, and had poor wettability but good workability. Here, poor wettability means that resin 203 has difficulty flowing into corners and the like within recess 170, leaving air bubbles within recess 170 or exposing the bottom surface of recess 170.

[0052] Resin 203 of specification D is a two-component epoxy resin (viscosity 1.2 Pa s) that has good wettability but poor workability. Here, poor workability means that, for example, when resin 203 is sequentially filled into recesses 170 of multiple fluid sensors 100 during the manufacturing process of the fluid sensor 100, the viscosity of resin 203 gradually increases, resulting in variations in the amount filled.

[0053] Evaluation of the prototype shown in FIG. 6 revealed that the specifications of the resin 203 filled in the recess 170 are preferably either of the following two. (1) A one-component epoxy resin mixed with 55% to 65% filler with a particle size of 1 to 4 μm. (2) A one-component epoxy resin mixed with 35% to 45% filler with a particle size of 20 to 50 μm.

[0054] (Fluid sensor manufacturing flow) Fig. 7 is a flow diagram showing an example of a method for manufacturing the fluid sensor 100 of Fig. 1. In the flow shown in Fig. 7, it is assumed that the sensor main body 101, in which the sensor chip 110 and various electronic components 161 are mounted on the substrate 120, has been manufactured in advance. It is also assumed that a filler has been mixed into the one-component epoxy resin in advance.

[0055] First, in step S10, substrate 120 of sensor main body 101 is bonded to lower housing 130. Next, in step S20, sensor main body 101 and lower housing 130, which have been bonded together, are preheated, and resin 203 of specification A or B in Fig. 6 is preheated. The preheating temperature is, for example, 50 to 60°C when the thermosetting temperature of resin 203 is 100 to 120°C.

[0056] Next, in step S30, resin 203 is filled into recess 170 of sensor main body 101. Thereafter, sensor main body 101 and lower housing 130, with resin 203 filled into recess 170, are heated to a thermosetting temperature, and resin 203 is hardened. By preheating sensor main body 101 and resin 203 to a temperature lower than the thermosetting temperature of resin 203, the viscosity of resin 203 can be reduced, and the wettability of resin 203 can be improved. As a result, the workability when filling recess 170 with resin 203 can be improved.

[0057] Furthermore, compared to two-component epoxy resins, one-component epoxy resins experience a gradual increase in viscosity over time, and also experience a gradual increase in viscosity when heated. This improves the workability of filling recess 170 with a specified amount of resin 203 compared to when sensor body 101 and resin 203 are not preheated, or compared to when two-component epoxy resins are used. Furthermore, because preheating reduces the viscosity of resin 203, it becomes possible to use resins with higher viscosity, thereby expanding the options for one-component epoxy resins.

[0058] Next, in step S40, a water-repellent coating agent is applied to the upper surfaces of sensor chip 110, protrusion 132, and resin 203, and is dried.

[0059] Next, in step S50, the upper housing 140 and the lower housing 130 are bonded together, completing the assembly of the fluid sensor 100 shown in Fig. 1. Next, in step S60, the assembled fluid sensor 100 undergoes final characteristic adjustment (trimming) and a final confirmation test, and defective products are removed, completing the fluid sensor 100.

[0060] As described above, in this embodiment, resin 203 is a one-component epoxy resin mixed with a filler, so that even a one-component epoxy resin with a higher viscosity than a two-component epoxy resin can have good wettability. This makes it possible to prevent air bubbles from remaining in recess 170 when resin 203 is filled, or to prevent the bottom surface of recess 170 (substrate 120) from being exposed.

[0061] As a result, the workability of filling the recess 170 with the resin 203 can be improved, and the frequency of repairs can be reduced. Furthermore, the improved wettability can prevent the bottom surface of the recess 170 from being exposed, thereby preventing corrosion of the terminals on the substrate 120. As a result, a fluid sensor 100 suitable for outdoor environments can be formed.

[0062] For example, workability during filling can be improved by filling recess 170 with resin 203 obtained by mixing 55% to 65% of filler having a particle size of 1 to 4 μm into one-component epoxy resin. Alternatively, workability during filling can be improved by filling recess 170 with resin 203 obtained by mixing 35% to 45% of filler having a particle size of 20 to 50 μm into one-component epoxy resin.

[0063] The improvement in wettability and workability can prevent the upper surface of the resin 203 from becoming concave or convex. This can prevent the airflow that passes through the upper surface of the resin 203 and flows into the sensor chip 110 from being turbulent at the upper surface of the resin 203. As a result, it is possible to prevent a decrease in the accuracy of measuring the flow velocity by the fluid sensor 100.

[0064] That is, it is possible to easily manage the amount of resin 203 filled, reduce variations in the flatness of resin 203, and suppress a decrease in the accuracy of measuring the flow velocity by fluid sensor 100. For example, by managing the filling of resin 203 to be 80% or more and 100% or less of the volume of recess 170, it is possible to ensure flatness between the surface of resin 203 and the upper surfaces of protrusion 132 and sensor chip 110.

[0065] By preheating the sensor main body 101 and the resin 203 to a temperature lower than the thermosetting temperature of the resin 203, the resin 203 can be filled into the recess 170 with reduced viscosity, further improving workability.

[0066] Although the present invention has been described above based on the embodiments, the present invention is not limited to the requirements shown in the above embodiments. These requirements can be changed without departing from the spirit of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0067] 100...fluid sensor, 101...sensor main body, 110...sensor chip, 120...substrate, 120a...through hole, 121...bonding wire, 130...lower housing, 131...outer frame, 132...protrusion, 140...upper housing, 141...lid, 142...support, 143...thick portion, 150...flow path, 161...electronic component, 170...recess, 180...protective film, 201, 202, 203...resin, 203a...filler, DMY...dummy wiring, MEMB...membrane, PAD...pad, PASF...protective film, Rd...thermosensitive element, Rh...heater resistor, Ru...thermosensitive element, SP...space, SUB...semiconductor substrate, TSNS...temperature sensor, W...wiring

Claims

1. a sensor chip mounted on the substrate for detecting a fluid flowing on the surface; a first housing disposed on the substrate and surrounding the sensor chip; a one-component resin containing a filler, the resin filling a recess between the sensor chip and the first housing; a second housing disposed on the first housing; a flow path for a fluid that flows on a surface of the sensor chip, the flow path being provided between the first housing and the second housing; The resin has a viscosity of 4 Pa·s and contains 55% to 65% (volume %) of filler having a particle size of 1 to 4 μm. Fluid sensor.

2. a sensor chip mounted on the substrate for detecting a fluid flowing on the surface; a first housing disposed on the substrate and surrounding the sensor chip; a one-component resin containing a filler, the resin filling a recess between the sensor chip and the first housing; a second housing disposed on the first housing; a flow path for a fluid that flows on a surface of the sensor chip, the flow path being provided between the first housing and the second housing; The resin has a viscosity of 10 Pa·s and contains 35% to 45% (volume %) of filler having a particle size of 20 to 50 μm. Fluid sensor.

3. The amount of the resin containing the filler filling the recess is 80% or more and 100% or less of the volume of the recess.

3. The fluid sensor according to claim 1.

4. a terminal provided on the substrate located in the recess and to which a bonding wire connected to a pad of the sensor chip is connected; 4. The fluid sensor according to claim 1.

5. The resin is an epoxy resin.

5. The fluid sensor according to claim 1.

6. A method for manufacturing a fluid sensor having a sensor chip mounted on a substrate and detecting a fluid flowing on a surface, comprising: a first housing is disposed on the substrate on which the sensor chip is mounted, surrounding the sensor chip; preheating a one-component epoxy resin containing a filler, the substrate, the sensor chip, and the first housing at a temperature lower than the curing temperature of the epoxy resin; filling the recess between the sensor chip and the first housing with the epoxy resin; Curing the epoxy resin; A second housing is disposed on the first housing to form a flow path for a fluid flowing on the surface of the sensor chip. A method for manufacturing a fluid sensor.

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