Pressure sensor

Abstract

A pressure sensor according to the present disclosure comprises a substrate, a detection element that is provided on an upper surface of the substrate and detects pressure, and a coating member that is provided on the upper surface of the substrate and covers a portion of the detection element. The coating member has a body provided on the upper surface of the substrate, a protruding part protruding upward from the upper surface of the body, and a recess that is recessed along the vertical direction from the upper surface of the protruding part and exposes a portion of the detection element. The recess has a tapered shape in which an opening surface decreases in size progressively away from the upper surface of the protruding part in the vertical direction. In a cross section cut along the vertical direction, an inner wall surface of the recess is recessed outward from a virtual straight line connecting an upper end part and a lower end part of the inner wall surface.

Description

Pressure Sensor

[0001] The present disclosure relates to a pressure sensor formed using MEMS (Micro Electro Mechanical Systems) technology.

[0002] A known example of this type of pressure sensor is described in Patent Document 1. The pressure sensor described in Patent Document 1 includes a substrate (base member), a detection element provided on the substrate, and a covering member (resin package) provided on the substrate and covering the detection element. The covering member has a rectangular parallelepiped main body provided on the substrate, a columnar ring holder extending from the top surface of the main body in a direction away from the substrate, and a recess recessed from the top of the ring holder toward the substrate, exposing a portion of the detection element.

[0003] US Patent Application Publication No. 2022 / 0190230

[0004] The covering member is made of, for example, resin and formed by a film-assisted molding (FAM) process, which is a type of transfer molding method. This process uses a lower mold on which a substrate is placed and an upper mold that is positioned so as to sandwich the substrate between the lower mold and the upper mold. The covering member is formed on the substrate by filling the space between the substrate and the upper mold with resin. A film is previously provided on the lower surface of the upper mold to prevent the resin from adhering to the upper mold. For example, the film is attached to the lower surface by suction through suction holes provided in the lower surface of the upper mold.

[0005] However, in conventional pressure sensors, when the upper mold and the film are removed from the covering member after the covering member is formed, there is a problem in that the film is difficult to peel from the covering member at the recessed portion.

[0006] Therefore, an object of the present disclosure is to solve the above-mentioned problems and to provide a pressure sensor in which the film can be easily peeled off from the covering member.

[0007] A pressure sensor according to the present disclosure comprises a substrate; a detection element provided on an upper surface of the substrate for detecting pressure; and a covering member provided on the upper surface of the substrate and covering a portion of the detection element, wherein the covering member has a main body provided on the upper surface of the substrate, a protrusion protruding upward from the upper surface of the main body, and a recess recessed in the vertical direction from the upper surface of the protrusion to expose a portion of the detection element, wherein the recess has a tapered shape in which the opening surface becomes smaller as it moves away from the upper surface of the protrusion in the vertical direction, and in a cross section cut in the vertical direction, the inner wall surface of the recess is recessed outward from an imaginary line connecting the upper end and lower end of the inner wall surface.

[0008] According to the present disclosure, it is possible to provide a pressure sensor in which the film can be easily peeled off from the covering member.

[0009] Fig. 2 is a plan view of a pressure sensor according to a first embodiment of the present disclosure; Fig. 3 is a cross-sectional view of the pressure sensor of Fig. 1 taken along line II-II; Fig. 4 is an enlarged cross-sectional view of an EA1 region of the pressure sensor of Fig. 2; Fig. 5 is a cross-sectional view showing an example of a manufacturing process for the pressure sensor of Fig. 2; Fig. 6 is a view showing a pressure sensor according to a second embodiment of the present disclosure, which is an enlarged cross-sectional view corresponding to the EA1 region in Fig. 2; Fig. 7 is a view showing a pressure sensor according to a third embodiment of the present disclosure, which is an enlarged cross-sectional view corresponding to the EA1 region in Fig. 2;

[0010] <Findings that Form the Basis of the Present Disclosure> The present inventors conducted extensive research to provide a pressure sensor in which the film can be easily peeled off from the covering member, and as a result, obtained the following new findings.

[0011] In the conventional pressure sensor, the recess has a tapered shape in which the opening becomes smaller in the vertical direction, i.e., the thickness direction of the substrate, toward the base member. Specifically, the recess has a bottom surface where a part of the detection element is exposed, and an inner wall surface that connects the top of the ring holder to the bottom surface. The inner wall surface extends in the vertical direction.

[0012] In the FAM process, after the coating member is formed, the film moves upward along the vertical direction together with the upper mold and is peeled off from the coating member. At this time, on the inner wall surface of the recess, the film moves along the surface direction of the inner wall surface that is aligned in the vertical direction, generating shear resistance between the film and the inner wall surface. Therefore, the portion of the film located on the inner wall surface is less likely to move in the vertical direction and is less likely to peel off from the coating member.

[0013] Therefore, the inventors came up with the idea of ​​providing a portion at the lower part of the inner wall surface that is angled larger relative to the vertical direction, i.e., a configuration in which, in a cross section along the vertical direction, the inner wall surface is recessed outward from an imaginary line connecting the upper and lower ends of the inner wall surface. By increasing the angle of the lower part of the inner wall surface relative to the vertical direction, the shear resistance is reduced, making it easier for the film to move upward. As a result, it becomes easier to peel the film from the covering member. Based on this novel finding, the inventors have come up with the following disclosure.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., terms including "up," "down," "right," and "left") will be used as necessary. However, the use of these terms is intended to facilitate understanding of the present disclosure with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present disclosure. Furthermore, the following description is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses. Furthermore, the drawings are schematic, and the ratios of the dimensions and the like do not necessarily correspond to reality.

[0015] In this specification, "electrically connected" includes the ability to conduct current between multiple components, multiple components being capacitively coupled, and multiple components being electromagnetically coupled.

[0016] First Embodiment A pressure sensor according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the pressure sensor according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the pressure sensor of FIG. 1 taken along line II-II. For convenience of explanation, an X-Y-Z Cartesian coordinate system is shown in the drawings, but this coordinate system is intended to facilitate understanding of the present disclosure and does not limit the present disclosure. The Z direction in this coordinate system is an example of the "up-down direction" in the present disclosure.

[0017] 1 and 2, the pressure sensor 1 includes a substrate 2, a detection element 3 provided on the substrate 2, and a covering member 4 provided on the substrate 2 so as to cover the detection element 3. Pressures measured by the pressure sensor 1 include absolute pressure, gauge pressure, differential pressure, and airflow pressure.

[0018] As shown in Fig. 2, the substrate 2 has a lower surface 2a and an upper surface 2b opposite thereto. For example, the substrate 2 is a wiring substrate such as a resin substrate, a ceramic substrate, or a lead frame. In this embodiment, the substrate 2 is a printed wiring board. As shown in Fig. 1, in this embodiment, the substrate 2 is a square having sides extending in the X direction or the Y direction in a plan view seen from the Z direction.

[0019] As shown in FIGS. 1 and 2 , a detection element 3 and a circuit element 21 are disposed on the upper surface 2b of the substrate 2. The detection element 3 is a pressure sensor element that detects pressure. For example, the detection element 3 is a piezo-resistive or capacitive pressure sensor element, and is a MEMS (Micro Electro Mechanical Systems) element. In this embodiment, the detection element 3 is formed in a rectangular parallelepiped shape and has an upper surface 3a opposite to the surface facing the upper surface 2b of the substrate 2. The detection element 3 has a detection unit 31 that is provided on the upper surface 3a and is subjected to pressure. For example, the detection unit 31 is a membrane or diaphragm that receives pressure.

[0020] For example, the circuit element 21 is an element that includes an application specific integrated circuit (ASIC). In this embodiment, the circuit element 21 includes a converter that converts the voltage signal output from the detection element 3 into a digital signal, a filter that filters the digital signal from the converter, a temperature sensor that detects temperature, a processor that corrects the filtered digital signal based on the temperature detected by the temperature sensor, and a memory that stores correction coefficients and the like that are used when correcting the digital signal using the detected temperature.

[0021] 2, the detection element 3 and the circuit element 21 are arranged side by side in the X direction on the upper surface 2b of the substrate 2. For example, the detection element 3 and the circuit element 21 are each bonded to the substrate 2 via an adhesive member such as a die attach film or a die bond material.

[0022] In this embodiment, the detection element 3 and the circuit element 21 are connected via bonding wires 22 extending from the upper surface 3 a of the detection element 3. Furthermore, the circuit element 21 and the substrate 2 are connected via bonding wires 23 extending from the surface of the circuit element 21. As a result, the circuit provided on the substrate 2, the detection element 3, and the circuit element 21 are electrically connected.

[0023] The detection element 3 and the circuit element 21 may be electrically connected via a circuit on the substrate 2. For example, the detection element 3 and the circuit element 21 may each be connected to the circuit on the substrate 2 via a bonding wire or a bump. Furthermore, the detection element 3 and the circuit element 21 may be arranged on the substrate 2 so as to overlap each other in the Z direction.

[0024] The covering member 4 is provided on the upper surface 2b of the substrate 2, and covers a portion of the detection element 3, the circuit element 21, and the bonding wires 22 and 23. The covering member 4 has a main body 41 provided on the upper surface 2b of the substrate 2, and a protruding portion 42 protruding upward from the main body 41 in the Z direction. The main body 41 has a lower surface 41a facing the substrate 2 and an upper surface 41b on the opposite side. The protruding portion 42 protrudes from the upper surface 41b of the main body 41. In this embodiment, the covering member 4 is made of resin. The main body 41 and the protruding portion 42 are integrally molded. In FIG. 2 and Figures 3 to 6 described below, the boundary between the main body 41 and the protruding portion 42 is indicated by a dashed line.

[0025] For example, each of the main body 41 and the protrusion 42 is circular, elliptical, or polygonal in plan view.

[0026] As shown in FIGS. 1 and 2, the main body 41 is a rectangular parallelepiped in this embodiment, and is provided on the entire upper surface 2 b of the substrate 2 .

[0027] The protrusion 42 has a truncated cone shape that tapers upward in the Z direction. The protrusion 42 has an upper surface 42a that is the top surface, and an outer wall surface 42b that connects the upper surface 42a to the upper surface 41b of the main body 41.

[0028] 1 and 2 , an O-ring 6 may be provided on the upper surface 41b of the main body 41 so as to surround the protrusion 42 in a plan view. For example, the O-ring 6 is made of an elastic material such as rubber or silicone. The O-ring 6 may be provided around the protrusion 42 in a stretched state and may contact the outer wall surface 42b of the protrusion 42. In this case, when the pressure sensor 1 is attached to an electronic device, the O-ring 6 is crushed and elastically deformed between the housing of the electronic component and the pressure sensor 1, and may prevent moisture from flowing between them.

[0029] The covering member 4 has a recess 5 that is recessed downward in the Z direction from the upper surface 42a of the protruding portion 42 and exposes a part of the detection element 3. For example, the recess 5 exposes the detection portion 31 of the detection element 3. In other words, the covering member 4 covers the detection element 3 except for the recess 5.

[0030] 2, in this embodiment, the recess 5 has a tapered shape in which the opening surface becomes smaller in the Z direction as it moves away from the upper surface 42a of the protrusion 42. In this embodiment, the recess 5 is formed in a rotationally symmetric shape about an imaginary central axis VA1 extending along the Z direction. The shape of the opening surface of the recess 5 is a substantially rectangular shape with rounded corners in a plan view.

[0031] The recess 5 has a bottom surface 5a where the detection element 3 is exposed, and an inner wall surface 5b connecting the bottom surface 5a and the upper surface 42a of the protrusion 42. The entire bottom surface 5a may be formed by the upper surface 3a of the detection element 3, or as shown in FIG. 1 , only a portion of the bottom surface 5a may be formed by the upper surface 3a, with the remaining portion being formed as the surface of the covering member 4.

[0032] The shape of the inner wall surface 5b of the recess 5 will be described with reference to a cross section cut along the Z direction (hereinafter also referred to as a "cut surface") shown in Figures 2 and 3. Figure 3 is an enlarged cross section of the EA1 region of the pressure sensor in Figure 2. In this embodiment, the cut surface is a surface that cuts the recess 5 and includes the imaginary central axis VA1. The cut surface may also be a surface that cuts the recess 5 without passing through the imaginary central axis VA1.

[0033] 3, in the cross section, the inner wall surface 5b of the recess 5 has an upper end 51 that is a connection portion with the upper surface 42a of the protrusion 42, and a lower end 52 that is a connection portion with the bottom surface 5a. The inner wall surface 5b is recessed outward from an imaginary line VL1 that connects the upper end 51 and the lower end 52. Here, "outward" refers to a direction that moves radially away from the imaginary central axis VA1 in a plan view. In this embodiment, in the cross section, the entire inner wall surface 5b is recessed outward from the imaginary line VL1.

[0034] The inner wall surface 5b is bent at at least one location on the cut surface. In the first embodiment, the inner wall surface 5b is bent at one bending position BP1. In the first embodiment, the bending position BP1 is located at the center MP between the upper end 51 and the lower end 52 of the inner wall surface 5b in the Z direction, or below the center MP.

[0035] The inner wall surface 5b has a plurality of divided sections on the cross section, which are separated by the bending position BP1. In this embodiment, the inner wall surface 5b has an upper divided section 531 connected to the upper end portion 51 and a lower divided section 532 connected to the lower end portion 52. Each of the upper divided section 531 and the lower divided section 532 is linear on the cross section.

[0036] In the cross section, the angle AG2 of the lower divided portion 532 with respect to the Z direction is larger than the angle AG1 of the upper divided portion 531 with respect to the Z direction. In the following description, the angle of the inner wall surface 5b with respect to the Z direction may be simply referred to as the angle of the inner wall surface 5b or the angle of the divided portion.

[0037] 4, a FAM process, which is an example of a method for forming the covering member 4 of the pressure sensor 1, will be described. FIG. 4 is a cross-sectional view showing an example of a manufacturing process for the pressure sensor of FIG.

[0038] In this process, the covering member 4 is formed using two molds: a lower mold 101 and an upper mold 102. In the process of forming the covering member 4, an aggregate substrate in which a large number of substrates 2 are arranged in the surface direction is placed on the lower mold 101. Figure 4 shows a portion of the aggregate substrate that corresponds to one pressure sensor 1. The substrate 2 on the lower mold 101 is provided with the detection element 3, circuit element 21, bonding wires 22, 23, etc.

[0039] The upper mold 102 is disposed above the lower mold 101 so as to sandwich the substrate 2 between the upper mold 102 and the lower mold 101. The upper mold 102 has a lower surface 102a that faces the lower mold 101 in the Z direction. The lower surface 102a has a shape corresponding to the shape of the covering member 4.

[0040] A film 103 is provided on the lower surface 102a to prevent the resin constituting the covering member 4 from adhering to the upper mold 102. The film 103 is sucked toward the lower surface 102a through suction holes (not shown) opened in the lower surface 102a of the upper mold 102. For example, the film 103 is a release film containing Teflon (registered trademark).

[0041] The resin that constitutes the covering member 4 is poured into the space between the substrate 2 and the upper mold 102 (more specifically, the film 103). The resin poured into the space is cured to form the covering member 4. Figure 4 shows the resin in a cured state.

[0042] Next, the upper mold 102 moves upward along the Z direction as shown by the arrow in Fig. 4. At this time, the film 103 also moves upward together with the upper mold 102 and is peeled off from the cured covering member 4.

[0043] In the pressure sensor 1 according to the first embodiment, the inner wall surface 5b of the recess 5 is recessed outward from the imaginary line VL1 connecting the upper end 51 and the lower end 52 of the inner wall surface 5b in a cut surface. This configuration allows the angle of the inner wall surface 5b to be increased at the lower part of the inner wall surface 5b (e.g., the lower divided portion 532) compared to a configuration in which the inner wall surface 5b is not recessed outward from the imaginary line VL1. This reduces the shear resistance generated between the inner wall surface 5b and the film 103 at the lower part of the inner wall surface 5b, making it easier to peel the film 103 from the covering member 4. This makes it possible to provide a pressure sensor 1 in which the film 103 can be easily peeled from the covering member 4.

[0044] Furthermore, because the inner wall surface 5b is recessed outward from the virtual line VL1, the angle of the upper portion of the inner wall surface 5b (e.g., angle AG1 of the upper divided portion 531) is smaller than the angle of the lower portion of the inner wall surface 5b (e.g., angle AG2 of the lower divided portion 532) on the cross section. This makes it possible to prevent the opening surface of the recess 5 on the upper surface 42a of the protrusion 42 from becoming larger, compared to a configuration in which the entire inner wall surface 5b is at the angle of the lower portion of the inner wall surface 5b. Therefore, it is possible to prevent the dimensions of the protrusion 42, the covering member 4, and the pressure sensor 1 in the X and Y directions from becoming larger.

[0045] Furthermore, by increasing the angle of the lower part of the inner wall surface 5b, the dimension in the XY directions between the lower part of the inner wall surface 5b (e.g., the lower divided part 532) and the outer wall surface 42b of the protrusion 42 (hereinafter also referred to as the "wall thickness of the lower part of the protrusion 42") becomes larger compared to conventional pressure sensors. This increases the mechanical strength of the lower part of the protrusion 42. Here, the lower part of the protrusion 42 refers to the part of the protrusion 42 that is located between the lower part of the inner wall surface 5b and the outer wall surface 42b in the direction perpendicular to the Z axis.

[0046] The increased mechanical strength of the lower portion of the protrusion 42 improves the durability of the protrusion 42 against pressure applied to the outer wall surface 42b by the elasticity of the O-ring 6. In addition, external impacts applied to the protrusion 42 are less likely to be transmitted to the detection element 3, improving the accuracy of the pressure detected by the detection element 3.

[0047] Furthermore, since the wall thickness of the lower part of the protrusion 42 is large, even if the position of the upper mold 102 in the X and Y directions is shifted from a predetermined position during the process of forming the covering member 4, the upper mold 102 is unlikely to come into contact with components to be covered by the covering member 4, such as the bonding wires 22 and 23. In other words, the tolerance for positional deviation of the upper mold 102 in the X and Y directions is increased, which makes it easier to manufacture the pressure sensor 1.

[0048] Furthermore, according to the pressure sensor 1 according to the first embodiment, the inner wall surface 5b is bent at least at one location on the cut surface. The upper mold 102 for forming the bent inner wall surface 5b can be manufactured more easily than an upper mold for forming the inner wall surface 5b having a smoothly curved wall surface without bending. Therefore, the pressure sensor 1 can be manufactured more easily than a pressure sensor having a configuration in which the inner wall surface 5b is not bent.

[0049] The portion of the film 103 located at the bottom of the inner wall surface 5b is located deeper in the recess 5 of the covering member 4 than the portion located at the top of the inner wall surface 5b (see FIG. 4 ). Therefore, the portion located at the bottom of the inner wall surface 5b is more difficult to peel off from the covering member 4 than the portion located at the top of the inner wall surface 5b.

[0050] In the pressure sensor 1 according to the first embodiment, the angle of the lower divided portion 532 is larger than the angle of the upper divided portion 531. That is, the angle of the inner wall surface 5b is larger in the region of the inner wall surface 5b where the film 103 is particularly difficult to peel off. Therefore, the film 103 can be more easily peeled off from the covering member 4.

[0051] Furthermore, in the pressure sensor 1 according to the first embodiment, the lowest bending position BP1 is located at the center MP between the upper end 51 and the lower end 52 of the inner wall surface 5b in the Z direction, or below the center MP. This allows the angle of the dividing portion below the bending position BP1 (e.g., the lower dividing portion 532) to be larger than in a configuration in which the bending position BP1 is located above the center MP. In other words, the angle of the inner wall surface 5b can be increased in an area of ​​the inner wall surface 5b where the film 103 is particularly difficult to peel. This further improves the ease with which the film 103 can be peeled from the covering member 4.

[0052] Second Embodiment A pressure sensor according to a second embodiment of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a diagram showing a pressure sensor according to the second embodiment of the present disclosure, and is an enlarged cross-sectional view corresponding to area EA1 in Fig. 2.

[0053] The pressure sensor 1A according to the second embodiment differs from the pressure sensor 1 according to the first embodiment in that the inner wall surface 5b has three or more divided sections on the cut surface. In the following description of the second embodiment, the same reference numerals will be used to designate the same components as those in the pressure sensor 1, and the description thereof may be omitted.

[0054] 5, in a cross section, the inner wall surface 5b of the pressure sensor 1A is recessed outward from the imaginary line VL1 connecting the upper end 51 and the lower end 52, similar to the pressure sensor 1 according to the first embodiment. The inner wall surface 5b is bent at two locations: a bending position BP1 and a bending position BP2 that is lower than the bending position BP1 in the Z direction.

[0055] For example, the uppermost bending position BP1 on the inner wall surface 5b is located at the center MP between the upper end 51 and the lower end 52 of the inner wall surface 5b in the Z direction, or below the center MP. In this embodiment, the bending position BP1 is located at the center MP in the Z direction.

[0056] The lowest bending position BP2 on the inner wall surface 5b is located at the center MP between the upper end 51 and the lower end 52 of the inner wall surface 5b in the Z direction, or below the center MP. In this embodiment, the bending position BP2 is located below the center MP in the Z direction.

[0057] The inner wall surface 5b has three divided sections on the cross section, separated by the bending positions BP1 and BP2. The portion of the inner wall surface 5b located above the bending position BP1 is an upper divided section 531 that connects to the upper end portion 51. The portion of the inner wall surface 5b located below the bending position BP2 is a lower divided section 532 that connects to the lower end portion 52. The portion of the inner wall surface 5b located between the bending positions BP1 and BP2 is a middle divided section 533. Each of the divided sections 531 to 533 is linear on the cross section.

[0058] In the cross section, the angle of any divided portion selected from the three or more divided portions 531 to 533 relative to the Z direction is larger than the angle of each divided portion located above the selected divided portion relative to the Z direction. In other words, the angle of each divided portion 531 to 533 increases as the divided portion 531 to 533 is positioned lower in the Z direction.

[0059] Specifically, the angle AG2 of the lower dividing portion 532, which is the dividing portion located lowest, is greater than both the angle AG1 of the upper dividing portion 531 located above the lower dividing portion 532 and the angle AG3 of the middle dividing portion 533. Furthermore, the angle AG3 of the middle dividing portion 533 is greater than the angle AG1 of the upper dividing portion 531 located above the middle dividing portion 533. In other words, of the angles AG1 to AG3 of the three dividing portions 531 to 533, the angle AG2 of the lowermost lower dividing portion 532 is the largest, and the angle AG1 of the uppermost upper dividing portion 531 is the smallest.

[0060] In the pressure sensor 1A according to the second embodiment, the angles of the divided portions 531 to 533 are larger as the divided portions 531 to 533 are positioned lower in the Z direction. With this configuration, the shear resistance with the film 103 decreases as the position on the inner wall surface 5b decreases, making it easier for the film 103 to peel off. Therefore, the film 103 is more easily peeled off from the covering member 4 in the deep portion of the recess 5 where it is particularly difficult to peel off the film 103.

[0061] Third Embodiment A pressure sensor according to a third embodiment of the present disclosure will be described with reference to Fig. 6. Fig. 6 is a diagram showing a pressure sensor according to the third embodiment of the present disclosure, and is an enlarged cross-sectional view corresponding to area EA1 in Fig. 2.

[0062] The pressure sensor 1B according to the third embodiment differs from the pressure sensor 1 according to the first embodiment in that the inner wall surface 5b is not bent at the cut surface, but instead has a curved portion. In the following description of the third embodiment, the same reference numerals will be used to designate the same components as those in the pressure sensor 1, and the description thereof may be omitted.

[0063] As shown in Figure 6, the inner wall surface 5b of the pressure sensor 1B is recessed outward from the imaginary line VL1 connecting the upper end 51 and the lower end 52 in the cross section, similar to the pressure sensor 1 of the first embodiment.

[0064] The inner wall surface 5b has a curved portion 534 that protrudes outward from the imaginary straight line VL1 on the cross section. The curved portion 534 has a curved upper end 534a at its upper end and a curved lower end 534b at its lower end. In this embodiment, the curved upper end 534a is located below the center MP between the upper end 51 and the lower end 52 of the inner wall surface 5b in the Z direction. Furthermore, the curved upper end 534a is located outward from the imaginary straight line VL1 on the cross section.

[0065] The curved lower end portion 534b constitutes the lower end portion 52 of the inner wall surface 5b in the cross section. That is, the curved portion 534 is connected to the bottom surface 5a of the recess 5.

[0066] The angle of the inner wall surface 5b of the curved portion 534 gradually increases downward. Here, the angle of the inner wall surface 5b of the curved portion 534 is, for example, the angle of the tangent line at each position of the curved portion 534 relative to the Z direction.

[0067] In this embodiment, the inner wall surface 5 b excluding the curved portion 534 is linear in cross section and connected to the upper end portion 51 .

[0068] In the pressure sensor 1B according to the third embodiment, the inner wall surface 5b has a curved portion 534 that protrudes outward from the imaginary line VL1 in the cross section. The angle of the inner wall surface 5b at the curved portion 534 gradually increases downward. As a result, the shear resistance between the curved portion 534 and the film 103 decreases the further downward on the inner wall surface 5b, making it easier for the film 103 to peel off.

[0069] In addition, in the curved inner wall surface 5b of the pressure sensors 1 and 1A according to the first and second embodiments, the angle of the inner wall surface 5b changes significantly between positions above and below the curved position. On the other hand, in the curved portion 534 of the pressure sensor 1B, the angle of the inner wall surface 5b changes gradually with the position in the Z direction. This further improves the ease of peeling the film 103 from the covering member 4.

[0070] Furthermore, in the pressure sensor 1B according to the third embodiment, the curved lower end 534b constitutes the lower end 52 of the inner wall surface 5b. Therefore, the lower part of the curved part 534, which has a large angle with respect to the Z direction, is provided at the lower part of the inner wall surface 5b (i.e., in the deep part of the recess 5). This further improves the ease of peeling the film 103 from the covering member 4 in the deep part of the recess 5, where peeling of the film 103 is particularly difficult.

[0071] The present disclosure is not limited to the above-described embodiment and can be embodied in various other forms. For example, in the above-described embodiment, the recess 5 is formed in a rotationally symmetric shape about the imaginary central axis VA1, but the present disclosure is not limited to this. For example, the inner wall surface 5b may be curved only in a partial region in the circumferential direction in a plan view, and may not be curved in the remaining region.

[0072] In addition, in the above embodiment, the entire inner wall surface 5b is recessed outward from the virtual line VL1 in the cross section, but only a portion of the inner wall surface 5b may be recessed outward from the virtual line VL1.

[0073] In the first embodiment, the lowest bending position BP1 is located at the center MP or below the center MP, but it may be located above the center MP. In the second embodiment, the lowest bending position BP2 is located at the center MP or below the center MP, but it may be located above the center MP.

[0074] In the second embodiment, the inner wall surface 5b is bent at two points on the cut surface, but it may be bent at three or more points.

[0075] In the third embodiment, the inner wall surface 5 b is not curved in the cross section, but the present disclosure is not limited to this. For example, the inner wall surface 5 b may be curved in a portion other than the curved portion 534.

[0076] In the third embodiment, the curved upper end 534a is located below the center MP, but the present disclosure is not limited to this. For example, the curved upper end 534a may be located at the center MP or above the center MP. The curved upper end 534a may also constitute the upper end 51 of the inner wall surface 5b. In other words, the entire inner wall surface 5b may be the curved portion 534 in the cross section.

[0077] Any of the various embodiments or modifications described above can be combined appropriately to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.

[0078] Although the present disclosure has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and such changes and modifications are to be understood as being included within the scope of the present disclosure as defined by the appended claims unless they depart therefrom.

[0079] Various embodiments of the present disclosure have been described in detail above with reference to the drawings. Finally, various aspects of the present disclosure will be described.

[0080] According to a first aspect of the present disclosure, there is provided a pressure sensor comprising: a substrate; a detection element provided on an upper surface of the substrate for detecting pressure; and a covering member provided on the upper surface of the substrate and covering a portion of the detection element, wherein the covering member has a main body provided on the upper surface of the substrate, a protrusion protruding upward from the upper surface of the main body, and a recess recessed in a vertical direction from the upper surface of the protrusion to expose a portion of the detection element, wherein the recess has a tapered shape in which the opening surface becomes smaller as it moves away from the upper surface of the protrusion in the vertical direction, and in a cross section cut in the vertical direction, the inner wall surface of the recess is recessed outward from an imaginary line connecting the upper end and lower end of the inner wall surface.

[0081] According to a second aspect of the present disclosure, there is provided the pressure sensor according to the first aspect, wherein the inner wall surface is bent at least at one location in the cross section.

[0082] According to a third aspect of the present disclosure, there is provided a pressure sensor as described in the second aspect, wherein, in the cross section, the inner wall surface has a plurality of divided sections separated by a bending position, the plurality of divided sections having upper divided sections connected to an upper end of the inner wall surface and lower divided sections connected to a lower end of the inner wall surface, and the angle of the lower divided sections relative to the vertical direction is greater than the angle of the upper divided sections relative to the vertical direction.

[0083] According to a fourth aspect of the present disclosure, there is provided a pressure sensor as described in the third aspect, wherein, in the cross section, the inner wall surface has three or more divided portions, and the angle of a divided portion arbitrarily selected from the three or more divided portions relative to the vertical direction is greater than the angle of each of the divided portions located above the selected divided portion relative to the vertical direction.

[0084] According to a fifth aspect of the present disclosure, there is provided a pressure sensor according to any one of the second to fourth aspects, wherein, in the cross section, the inner wall surface is bent at at least one location, and the lowest bent position on the inner wall surface is located at the center between the upper and lower ends of the inner wall surface in the vertical direction, or below the center.

[0085] According to a sixth aspect of the present disclosure, there is provided the pressure sensor according to any one of the first to fifth aspects, wherein in the cross section, the inner wall surface has a curved portion that protrudes outward from the imaginary straight line.

[0086] According to a seventh aspect of the present disclosure, there is provided the pressure sensor according to the sixth aspect, wherein, in the cross section, a lower end of the curved portion constitutes a lower end of the inner wall surface.

[0087] The pressure sensor according to the present disclosure is useful as a variety of pressure sensors because the film can be easily peeled off from the covering member.

[0088] 1, 1A, 1B Pressure sensor 2 Substrate 2b Upper surface 3 Detection element 4 Covering member 41 Main body 41b Upper surface 42 Protrusion 42a Upper surface 5 Recess 5b Inner wall surface 51 Upper end 52 Lower end 531 Upper divided portion 532 Lower divided portion 534 Curved portion 534b Curved lower end AG1, AG2 Angle BP1 Bending position MP Center VL1 Virtual straight line

Claims

1. A pressure sensor comprising: a substrate; a detection element provided on an upper surface of the substrate for detecting pressure; and a covering member provided on the upper surface of the substrate and covering a portion of the detection element, wherein the covering member has a main body provided on the upper surface of the substrate, a protrusion protruding upward from the upper surface of the main body, and a recess recessed in a vertical direction from the upper surface of the protrusion to expose a portion of the detection element, wherein the recess has a tapered shape whose opening surface becomes smaller the further away from the upper surface of the protrusion in the vertical direction, and in a cross section cut in the vertical direction, an inner wall surface of the recess is recessed outward from an imaginary straight line connecting an upper end and a lower end of the inner wall surface.

2. The pressure sensor according to claim 1, wherein said inner wall surface is bent at least at one location in said cross section.

3. A pressure sensor as described in claim 2, wherein, in the cross section, the inner wall surface has a plurality of divided portions separated by a bending position, the plurality of divided portions having upper divided portions connected to an upper end portion of the inner wall surface and lower divided portions connected to a lower end portion of the inner wall surface, and an angle of the lower divided portions relative to the vertical direction is greater than an angle of the upper divided portions relative to the vertical direction.

4. A pressure sensor as described in claim 3, wherein, in the cross section, the inner wall surface has three or more divided portions, and the angle of any one of the divided portions selected from the three or more divided portions in the vertical direction is greater than the angle of each of the divided portions located above the selected divided portion in the vertical direction.

5. A pressure sensor as claimed in any one of claims 2 to 4, wherein, in the cross section, the inner wall surface is bent at at least one location, and the lowest bent position on the inner wall surface is located in the middle between the upper and lower ends of the inner wall surface in the vertical direction, or below said middle.

6. The pressure sensor according to any one of claims 1 to 5, wherein in the cross section, the inner wall surface has a curved portion that protrudes outward from the imaginary straight line.

7. The pressure sensor according to claim 6, wherein in said cross section, a lower end of said curved portion constitutes a lower end of said inner wall surface.

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