Pressure sensor element

Abstract

Provided is a pressure sensor element capable of suppressing a decrease in detection sensitivity under a wide range of pressures. The pressure sensor element is provided with: a conductive base; an intermediate layer that is laminated on the base and has an opening; and an electrode that is laminated on the intermediate layer and has a diaphragm section facing the opening. The opening has a through-hole penetrating the intermediate layer in the lamination direction, and a pair of recesses provided on the upper surface of the intermediate layer so as to sandwich the through-hole. The intermediate layer is provided with a base-side conductive layer that constitutes the bottom surfaces of the pair of recesses. The diaphragm section faces the base-side conductive layer with the pair of recesses therebetween, faces the base with the through-hole therebetween, and is electrically insulated from the base-side conductive layer and the base. The pressure sensor element is further provided with a pair of opposing portions protruding toward the pair of recesses from at least one of the base-side conductive layer and the diaphragm portion. The pair of opposing portions is positioned so as to overlap with the through-hole-side end portions of the pair of recesses when viewed from the stacking direction.

Description

Technical Field

[0001] This invention relates to a pressure sensor element for detecting pressure. Background Technology

[0002] Pressure sensor elements capable of detecting capacitance changes over a wide range from low to high pressure are known (e.g., Patent Documents 1 and 2).

[0003] The pressure sensor element disclosed in Patent Document 1 includes a first electrode and a second electrode that are spatially insulated from each other. The second electrode flexes under pressure. The change in capacitance between the first and second electrodes is detected based on the change in the distance between them. The pressure acting on the second electrode is determined based on the detected change in capacitance.

[0004] In the pressure sensor element disclosed in Patent Document 1, a support portion protrudes from the second electrode into space. The support portion is annular when viewed from above. When the pressure applied to the second electrode is low, the support portion separates from the first electrode. At this time, the portion of the second electrode located outside and inside the support portion flexes as a membrane. If the pressure applied to the second electrode increases, the second electrode flexes, causing the support portion to contact the first electrode. When the second electrode flexes while the support portion is in contact with the first electrode, the portion of the second electrode located outside and inside the support portion flexes as different membranes. These different membranes have higher stiffness than the single membrane. Therefore, it is possible to use these different membranes to detect capacitance changes corresponding to higher pressures.

[0005] Patent Document 2 discloses a pressure sensor element comprising a fixed electrode and a diaphragm positioned opposite each other with a gap between them. The diaphragm flexes under pressure. The change in capacitance between the fixed electrode and the diaphragm is detected based on the change in the gap between them. The pressure acting on the diaphragm is determined based on the detected change in capacitance.

[0006] In the pressure sensor element disclosed in Patent Document 2, a protrusion is provided at the center of a fixed electrode covered by an insulating membrane. The gap between the center of the fixed electrode and the diaphragm is narrower than the gap between the periphery of the fixed electrode and the diaphragm. Therefore, when a higher pressure is applied to the diaphragm, the center of the fixed electrode contacts the diaphragm through the insulating membrane. At this time, the change in capacitance between the fixed electrode and the diaphragm is detected based on the change in the gap at the periphery of the fixed electrode.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Publication No. 2018-521317

[0010] Patent Document 2: Japanese Patent Application Publication No. 2005-321257 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] In the pressure sensor element disclosed in Patent Document 1, if the distance between the first electrode and the second electrode is widened, the detection sensitivity of capacitance changes when the pressure applied to the second electrode is low becomes lower. On the other hand, if the distance between the first electrode and the second electrode is narrowed, the possibility of the second electrode contacting the first electrode increases when the pressure applied to the second electrode is high. If the second electrode contacts the first electrode, capacitance changes cannot be detected.

[0013] In the pressure sensor element disclosed in Patent Document 2, when high pressure is applied to the diaphragm, the center portion of the fixed electrode contacts the diaphragm through an insulating film, thus the gap at the center of the fixed electrode remains unchanged. Therefore, the capacitance change between the fixed electrode and the diaphragm is detected only based on the change in the gap at the periphery of the fixed electrode. Consequently, compared to a structure that detects the capacitance change between the fixed electrode and the diaphragm based on changes in the gaps at both the center and periphery of the fixed electrode, the sensitivity for detecting capacitance changes is reduced.

[0014] The purpose of this invention is to provide a pressure sensor element that can suppress the reduction in detection sensitivity of capacitance changes with respect to a wide range of pressures from low to high pressures.

[0015] Solution for solving the problem

[0016] One technical solution of the present invention comprises a pressure sensor element having:

[0017] A conductive base;

[0018] An intermediate layer, which is stacked on the base and has an opening; and

[0019] A conductive electrode, stacked on the side of the intermediate layer opposite to the side where the base is located, has a diaphragm portion that overlaps with the opening when viewed from the stacking direction. This electrode is electrically insulated from the base.

[0020] The opening has:

[0021] Through-hole, which penetrates the intermediate layer in the stacking direction; and

[0022] A pair of recesses, which are continuously disposed on the electrode-side surface of the intermediate layer, sandwiching the through hole, and are recessed along the stacking direction.

[0023] The intermediate layer includes a base-side conductive layer, which forms the bottom surface of the pair of recesses and is electrically connected to the base.

[0024] The diaphragm portion is opposite to the substrate-side conductive layer in the stacking direction, separated by the pair of recesses, and is opposite to the substrate in the stacking direction, separated by the through-hole.

[0025] The pressure sensor element further includes a protrusion disposed on the surface of at least one of the base-side conductive layer and the diaphragm portion on the side of the pair of recesses, and protruding toward the pair of recesses.

[0026] The protrusion has a pair of opposing portions that are spaced apart from each other in the direction in which the through hole is sandwiched between the pair of recesses, i.e., in the width direction.

[0027] The pair of opposing portions are positioned to overlap with the ends of the pair of recesses on the through-hole side when viewed from the stacking direction.

[0028] The effects of the invention

[0029] According to the present invention, a pressure sensor element capable of suppressing the decrease in detection sensitivity under a wide pressure range from low pressure to high pressure can be provided. Attached Figure Description

[0030] Figure 1 This is a schematic end view of the pressure sensor element according to the first embodiment of the present invention.

[0031] Figure 2 This is a schematic top view of the portion of the pressure sensor element after the electrodes have been removed, according to the first embodiment of the present invention.

[0032] Figure 3 This is a schematic end view of the electrode in the pressure sensor element of the first embodiment of the present invention when low pressure is applied.

[0033] Figure 4 This is a schematic end view of the electrode when high pressure is applied in the pressure sensor element according to the first embodiment of the present invention.

[0034] Figure 5 This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0035] Figure 6 This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0036] Figure 7This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0037] Figure 8 This is a schematic top view of the portion of the pressure sensor element after the electrodes have been removed, according to the second embodiment of the present invention.

[0038] Figure 9 The pressure sensor element in the third embodiment of the present invention is related to... Figure 1 A schematic end face view of the corresponding part.

[0039] Figure 10 This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0040] Figure 11 This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0041] Figure 12 This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part. Detailed Implementation

[0042] The following description, with reference to the accompanying drawings, illustrates one example of the invention. The description is merely illustrative and not intended to limit the invention, its applications, or its uses. Furthermore, the drawings are schematic, and the scale and proportions may not correspond to reality. Additionally, in the following description, terms indicating specific directions or positions (e.g., terms such as "up," "down," "right," "left," "front," and "back") are sometimes used as needed. However, the use of terms indicating specific directions or positions is for ease of understanding of the invention with reference to the accompanying drawings, and the technical scope of the invention is not limited by the meaning of these terms.

[0043] <First Embodiment>

[0044] Figure 1 This is a schematic end view of the pressure sensor element according to the first embodiment of the present invention. Figure 2 This is a schematic top view of the portion of the pressure sensor element after the electrodes have been removed, according to the first embodiment of the present invention. Additionally, Figure 1 and the following Figures 3-7 , Figures 9-12 Is with Figure 2 A schematic end view of the part corresponding to section AA.

[0045] Figure 1 and Figure 2The pressure sensor element 1 shown is used to detect pressure. Pressure sensor element 1 is a capacitive element. In the first embodiment, pressure sensor element 1 is a MEMS (Micro Electro Mechanical Systems) element. Pressure sensor element 1 is, for example, mounted on mobile bodies such as automobiles, consumer devices such as smartphones and smartwatches.

[0046] The pressure sensor element 1 is cuboid in shape. However, the shape of the pressure sensor element 1 is not limited to a cuboid (which is a quadrilateral when viewed from the stacking direction 101). For example, the pressure sensor element 1 may also be a polygon other than a quadrilateral when viewed from the stacking direction 101, or it may be a cylinder.

[0047] like Figure 1 and Figure 2 As shown, the pressure sensor element 1 includes a base 10, an intermediate layer 20, an electrode 30, and a protrusion 40. The intermediate layer 20 is stacked on the base 10. The electrode 30 is stacked on the side of the intermediate layer 20 opposite to the side where the base 10 is located. The protrusion 40 is provided on the intermediate layer 20.

[0048] In the first embodiment, when viewed from above in the stacking direction 101 (the direction in which the base 10, intermediate layer 20, and electrode 30 are stacked), the base 10 is rectangular. The base 10 is conductive. In the first embodiment, the base 10 is formed of silicon (Si). The material forming the base 10 is not limited to silicon. As described above, the shape of the pressure sensor element 1 is not limited to a cuboid shape. Therefore, for example, when the pressure sensor element 1 is cylindrical, the base 10 appears circular when viewed from above. That is, when viewed from above, the base 10 is not limited to a rectangle.

[0049] In the first embodiment, the intermediate layer 20 is rectangular when viewed from above. Similar to the base 10, the intermediate layer 20 is not limited to a rectangular shape when viewed from above. The intermediate layer 20 includes a first base-side insulating layer 21 with insulating properties, a base-side conductive layer 22 with conductive properties, and a second base-side insulating layer 23 with insulating properties. The first base-side insulating layer 21 is stacked on the base 10. The base-side conductive layer 22 is stacked on the side of the first base-side insulating layer 21 opposite to the side where the base 10 is located. The second base-side insulating layer 23 is stacked on the side of the base-side conductive layer 22 opposite to the side where the first base-side insulating layer 21 is located.

[0050] In the first embodiment, the first base-side insulating layer 21 and the second base-side insulating layer 23 are formed of silicon dioxide (SiO2), and the base-side conductive layer 22 is formed of polycrystalline silicon (Poly-Si). The materials forming the first base-side insulating layer 21 and the second base-side insulating layer 23 are not limited to silicon dioxide. The materials forming the first base-side insulating layer 21 and the second base-side insulating layer 23 may also be different materials. The material forming the base-side conductive layer 22 is not limited to polycrystalline silicon.

[0051] The base-side conductive layer 22 has a fixed electrode 221 and a surrounding conductive layer 222 that surrounds the fixed electrode 221 when viewed from above.

[0052] A gap 22A is formed between the fixed electrode 221 and the surrounding conductive layer 222. As a result, the fixed electrode 221 is electrically insulated from the surrounding conductive layer 222.

[0053] like Figure 1 As shown, the fixed electrode 221 is electrically connected to the base 10 via a through hole 21A that penetrates the first base-side insulating layer 21 in the stacking direction 101.

[0054] like Figure 1 and Figure 2 As shown, the intermediate layer 20 has an opening 20A. In the first embodiment, the opening 20A has a through hole 20B and a pair of recesses 20C and 20D. The through hole 20B penetrates the intermediate layer 20 in the stacking direction 101. The pair of recesses 20C and 20D are formed on the upper surface 20E of the intermediate layer 20, recessed from the upper surface 20E of the intermediate layer 20 along the stacking direction 101. The upper surface 20E of the intermediate layer 20 is the surface of the intermediate layer 20 on the side closest to the electrode 30.

[0055] The through-hole 20B extends along the long side direction 103. The long side direction 103 is parallel to the long side of the rectangle of the pressure sensor element 1 when viewed from above. The long side direction 103 is orthogonal to the stacking direction 101. The through-hole 20B communicates with the gap 22A at both ends along the long side direction 103. The bottom surface of the through-hole 20B is formed by the upper surface of the base 10. The side surface of the through-hole 20B is formed by the side surface of the first base-side insulating layer 21 and the base-side conductive layer 22. The depth D1 of the through-hole 20B is the same as the thickness of the intermediate layer 20 (the total thickness of the first base-side insulating layer 21, the base-side conductive layer 22, and the second base-side insulating layer 23).

[0056] A pair of recesses 20C and 20D penetrate the second base-side insulating layer 23. On the other hand, the pair of recesses 20C and 20D are not provided in the base-side conductive layer 22 and the first base-side insulating layer 21. The pair of recesses 20C and 20D communicate with the gap 22A. The upper surface of the base-side conductive layer 22 (the surface of the base-side conductive layer 22 on the side of the pair of recesses 20C and 20D) constitutes the bottom surface 20Ca of recess 20C and the bottom surface 20Da of recess 20D. Specifically, a portion of the surrounding conductive layer 222 and the fixed electrode 221 constitute the bottom surfaces 20Ca and 20Da. The side surface of the second base-side insulating layer 23 constitutes the side surface of the pair of recesses 20C and 20D. The depth D2 of the pair of recesses 20C and 20D is the same as the thickness of the second base-side insulating layer 23. The depth D2 of the pair of recesses 20C and 20D is shallower than the depth D1 of the through hole 20B.

[0057] A pair of recesses 20C and 20D are spaced apart and face each other along the short side direction 102. The short side direction 102 is the direction parallel to the short side of the rectangle of the pressure sensor element 1 when viewed from above. The short side direction 102 is orthogonal to the stacking direction 101 and the long side direction 103. The short side direction 102 is an example of the width direction. Furthermore, the short side direction 102 and the long side direction 103 do not necessarily have to be orthogonal; they only need to intersect each other.

[0058] A through hole 20B is provided between a pair of recesses 20C and 20D. That is, the pair of recesses 20C and 20D sandwich the through hole 20B in the short side direction 102. The pair of recesses 20C and 20D are connected to the through hole 20B. In other words, the pair of recesses 20C and 20D are continuously provided with the through hole 20B.

[0059] like Figure 1 As shown, electrode 30 is stacked on the second base-side insulating layer 23 of intermediate layer 20. In the first embodiment, electrode 30 is rectangular when viewed from above. Similar to the base 10 described above, electrode 30 is not limited to a rectangular shape when viewed from above. Electrode 30 is conductive. Electrode 30 is electrically insulated from base 10.

[0060] In the first embodiment, the electrode 30 is formed of silicon (Si). The material for forming the electrode 30 is not limited to silicon.

[0061] Electrode 30 has a diaphragm portion 31. Diaphragm portion 31 is the portion of electrode 30 facing the opening 20A of intermediate layer 20. In other words, diaphragm portion 31 is the portion of electrode 30 that overlaps with opening 20A when viewed from the stacking direction 101. Diaphragm portion 31 is flexible. For example, by applying pressure to a main surface 30A of electrode 30, diaphragm portion 31 can bend downward, that is, towards opening 20A.

[0062] The diaphragm portion 31 is opposite to the substrate-side conductive layer 22 in the stacking direction 101 via a pair of recesses 20C and 20D, and is opposite to the substrate 10 in the stacking direction 101 via a through hole 20B.

[0063] like Figure 1 and Figure 2 As shown, the protrusion 40 is disposed on the upper surface of the fixed electrode 221 of the conductive layer 22 on the base side, that is, on the bottom surfaces 20Ca and 20Da of the pair of recesses 20C and 20D. The protrusion 40 protrudes upward from the bottom surfaces 20Ca and 20Da. In other words, the protrusion 40 protrudes from the bottom surfaces 20Ca and 20Da toward the pair of recesses 20C and 20D.

[0064] In the first embodiment, the protrusion 40 is insulating. In the first embodiment, the protrusion 40 is formed of silicon dioxide (SiO2) or silicon nitride (SiN). The material constituting the protrusion 40 is not limited to silicon dioxide (SiO2) or silicon nitride (SiN).

[0065] The protrusion 40 has a pair of opposing portions 41 and 42. In the first embodiment, the protrusion 40 is composed of a pair of opposing portions 41 and 42. The opposing portion 41 is provided on the bottom surface 20Ca. The opposing portion 42 is provided on the bottom surface 20Da.

[0066] A pair of opposing portions 41, 42 are disposed at the ends of the bottom surfaces 20Ca, 20Da on the side of the through hole 20B in the short side direction 102. In other words, the pair of opposing portions 41, 42 are positioned to overlap with the ends of the pair of recesses 20C, 20D on the side of the through hole 20B when viewed from above.

[0067] A pair of opposing parts 41 and 42 extend in a straight line along the long side direction 103. The pair of opposing parts 41 and 42 are parallel to each other. The long side direction 103 is an example of the direction of extension.

[0068] A pair of opposing portions 41 and 42 are spaced apart from each other in the direction in which a pair of recesses 20C and 20D sandwich the through hole 20B. In the first embodiment, the direction in which the pair of recesses 20C and 20D sandwich the through hole 20B is the short side direction 102.

[0069] like Figure 2 As shown, when viewed from above, the area on the short side 102 of the diaphragm portion 31 between a pair of opposing portions 41 and 42 is rectangular. In other words, when viewed from above, the area is... Figure 2 The area enclosed by the four virtual straight lines LN1, LN2, LN3, and LN4 shown in the dashed line is a rectangle.

[0070] Virtual line LN1 is a line that passes through the opposite portion 41 and extends along the long side direction 103. Virtual line LN3 is a line that passes through the opposite portion 42 and extends along the long side direction 103. Virtual lines LN1 and LN3 extend to the outer side of the pair of opposite portions 41 and 42 along the long side direction 103. Virtual line LN2 is a line that extends along the short side direction 102 on the side surface 23A of the second base-side insulating layer 23 (the surface extending along the lamination direction 101) facing the long side direction 103. Virtual line LN4 is a line that extends along the short side direction 102 on the side surface 23B of the second base-side insulating layer 23 facing the other side direction 103. Virtual lines LN2 and LN4 intersect virtual lines LN1 and LN3, respectively.

[0071] In the first embodiment, the length L of each of the pair of opposing portions 41 and 42 along the long side direction 103 is longer than the distance G along the short side direction 102 of the pair of opposing portions 41 and 42.

[0072] In the first embodiment, the distance G in the short side direction 102 between the pair of opposing portions 41, 42 is longer than the shortest distance D3 in the short side direction 102 between each pair of opposing portions 41, 42 and the outer edge of the opening 20A.

[0073] Figure 3 This is a schematic end view of the electrode in the pressure sensor element of the first embodiment of the present invention when low pressure is applied. Figure 4 This is a schematic end view of the electrode when high pressure is applied in the pressure sensor element according to the first embodiment of the present invention.

[0074] The following is for reference Figure 3 and Figure 4 This describes the operation of the diaphragm portion 31 of the electrode 30 when pressure is applied to one of its main surfaces 30A, and the detection of the electrostatic capacitance corresponding to this operation.

[0075] As described above, the diaphragm portion 31 faces the substrate-side conductive layer 22 in the stacking direction 101 across a pair of recesses 20C and 20D, and faces the substrate 10 in the stacking direction 101 across a through hole 20B. Thus, as Figure 3 As shown by the dashed line, capacitor C1 is formed by a diaphragm portion 31 and a fixed electrode 221 facing each other across a recess 20C. Capacitor C2 is formed by a diaphragm portion 31 and a fixed electrode 221 facing each other across a recess 20D. Capacitor C3 is formed by a diaphragm portion 31 and a base 10 facing each other across a through hole 20B. This allows for a circuit where these three capacitors C1, C2, and C3 are connected in parallel in an equivalent manner.

[0076] The base 10 and the electrode 30, including the diaphragm portion 31, can be electrically connected to external devices, components, etc. via terminals not shown. Therefore, the pressure applied to one main surface 30A of the electrode 30 can be measured using external devices, components, etc., based on the total electrostatic capacitance of the three capacitors C1, C2, and C3.

[0077] When pressure is applied to one of the main surfaces 30A of electrode 30, such as Figure 3 As shown, the diaphragm portion 31 of the electrode 30 flexes downward toward the base 10. When the pressure acting on one of the main surfaces 30A is small, the flexure amount of the diaphragm portion 31 is small. At this time, the diaphragm portion 31 separates from the pair of opposing portions 41, 42 of the protrusion 40. Therefore, the diaphragm portion 31 flexes as a membrane.

[0078] By flexing the diaphragm portion 31, the distance in the stacking direction 101 between the diaphragm portion 31 and the conductive layer 22 on the substrate side, and the distance in the stacking direction 101 between the diaphragm portion 31 and the substrate 10, respectively, decrease. These changes in distance increase the electrostatic capacitance of each of the capacitors C1, C2, and C3. Based on these changes in electrostatic capacitance, the current flowing through external devices and components, and the voltage applied to external devices and components, change. The pressure acting on one main surface 30A of the electrode 30 is measured based on these changes in current and voltage.

[0079] When a pressure higher than the aforementioned pressure is applied to a main surface 30A, the deflection of the diaphragm portion 31 increases. At this time, the diaphragm portion 31 comes into contact with a pair of opposing portions 41, 42. If the diaphragm portion 31, while in contact with the pair of opposing portions 41, 42, further deflects downward toward the base 10, as... Figure 4 As shown, in the diaphragm section 31, the portions corresponding to capacitor C1, C2, and C3 are flexed as three different membranes. The stiffness of each portion of the diaphragm section 31 corresponding to these three membranes is different from that of the diaphragm section 31 corresponding to a single membrane (see reference). Figure 3 It has high stiffness. Therefore, in Figure 4 In the state shown, with Figure 3 Compared to the state shown, the diaphragm portion 31 is less prone to bending. As a result, the upper limit of the pressure that can be measured by the pressure sensor element 1 can be increased.

[0080] According to the first embodiment, when the deflection of the diaphragm portion 31 is small, that is, when a lower pressure is applied to the diaphragm portion 31, the diaphragm portion 31 does not contact the pair of opposing portions 41, 42. At this time, based on the capacitance change between the diaphragm portion 31 and the substrate-side conductive layer 22 and the capacitance change between the diaphragm portion 31 and the substrate 10, the lower pressure applied to the diaphragm portion 31 can be measured with high sensitivity. When the deflection of the diaphragm portion 31 is large, that is, when a higher pressure is applied to the diaphragm portion 31, the diaphragm portion 31 contacts the pair of opposing portions 41, 42. At this time, the diaphragm portion 31 functions as a different membrane between the pair of opposing portions 41, 42 and on both outer sides of the pair of opposing portions 41, 42. In this case, each of these different membranes has higher stiffness. Therefore, the higher pressure applied to the diaphragm portion 31 can be measured with high sensitivity.

[0081] According to the first embodiment, when viewed from the stacking direction 101, the through hole 20B is located between a pair of opposing portions 41, 42, and the pair of recesses 20C, 20D are located on both outer sides of the pair of opposing portions 41, 42. Here, the depth D1 of the through hole 20B is deeper than the depth D2 of the pair of recesses 20C, 20D. Therefore, it is possible to reduce the possibility that the diaphragm portion 31, which flexes between the pair of opposing portions 41, 42, will come into contact with the base 10 when a higher pressure is applied to the diaphragm portion 31.

[0082] When the diaphragm portion is square when viewed from the stacking direction 101, the displacement of the diaphragm portion is greatest at a point in the center when pressure is applied, and the displacement decreases as it moves away from the center. In contrast, in the first embodiment, the portion of the diaphragm portion 31 surrounded by four virtual straight lines LN1, LN2, LN3, and LN4 is rectangular when viewed from the stacking direction 101. In the rectangular diaphragm portion 31 as in the first embodiment, when pressure is applied, the displacement of the diaphragm portion 31 is greatest at the center along the short side of the rectangle, and the displacement decreases as it moves away from the center. The portion with the greatest displacement extends along the long side of the rectangle. In other words, in the rectangular diaphragm portion 31 when viewed from the stacking direction 101, the portion with the greatest displacement is not a point but a line. That is, in the diaphragm portion 31, which is rectangular when viewed from the stacking direction 101, the area where the displacement of the diaphragm portion is constant can be increased compared to the diaphragm portion, which is square when viewed from the stacking direction 101. As a result, the capacitance change caused by the deflection of the portion of the diaphragm portion 31 surrounded by four virtual straight lines LN1, LN2, LN3, and LN4 can be detected with high precision.

[0083] For example, when the diaphragm portion is circular, the only means of adjusting its size is to change the diameter of the circle. According to the first embodiment, the portion of the diaphragm portion 31 surrounded by four virtual straight lines LN1, LN2, LN3, and LN4 is rectangular. In this case, the means of adjusting the size of the diaphragm portion 31 are to change the length of the long side of the rectangle and to change the length of the short side of the rectangle. Therefore, in the first embodiment, compared to a structure where the diaphragm portion is circular, the size and shape of the diaphragm portion can be freely changed in a way that matches the shape of the pressure sensor element.

[0084] According to the first embodiment, the rectangle surrounded by the four virtual straight lines LN1, LN2, LN3, and LN4 can be designed as a rectangle with the extension direction (long side direction 103) of each of the pair of opposing portions 41 and 42 as its long side. This allows the pair of opposing portions 41 and 42 to be longer in the extension direction, thus increasing the contact area when the diaphragm portion 31 contacts the pair of opposing portions 41 and 42. This improves the stability of the diaphragm portion 31 when in contact with the pair of opposing portions 41 and 42.

[0085] According to the first embodiment, the distance G between the pairs of opposing portions 41 and 42 in the short side direction 102 is longer than the shortest distance D3 between each pair of opposing portions 41 and 42 and the outer edge of the opening 20A in the short side direction 102. In this case, regardless of whether the shape of the opening 20A is a square or a rectangle, the area between the pairs of opposing portions 41 and 42 can be rectangular.

[0086] Figure 5 This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end view of the corresponding part. For example... Figure 5 As shown, the protrusion 40 can also be provided on the diaphragm portion 31.

[0087] A protrusion 40 is provided on the surface of the diaphragm portion 31 on the side of a pair of recesses 20C, 20D (in other words, the lower surface of the diaphragm portion 31). The protrusion 40 protrudes downward from the diaphragm portion 31. In other words, the protrusion 40 protrudes from the diaphragm portion 31 toward the pair of recesses 20C, 20D.

[0088] Figure 5 The convex part 40 shown is also related to Figure 1 and Figure 2 The convex portion 40 shown also has a pair of opposing portions 41 and 42. The pair of opposing portions 41 and 42 extend along the long side direction 103. The pair of opposing portions 41 and 42 are spaced apart from each other in the short side direction 102. The pair of opposing portions 41 and 42 are positioned to overlap with the ends of the pair of recesses 20C and 20D on the side near the through hole 20B when viewed from above. That is to say, Figure 5The positions of the pair of opposing parts 41 and 42 in the short side direction 102 shown are... Figure 1 and Figure 2 The positions of the pair of opposite parts 41 and 42 shown are the same in the short side direction 102.

[0089] The protrusion 40 can also be provided on both the substrate-side conductive layer 22 and the diaphragm portion 31. That is, the protrusion 40 can also be provided on at least one of the substrate-side conductive layer 22 and the diaphragm portion 31.

[0090] The pair of opposing parts 41 and 42 may not extend in a straight line. For example, the pair of opposing parts 41 and 42 may also be curved, or they may extend while undulating.

[0091] A pair of opposing parts 41 and 42 may not be parallel to each other.

[0092] The pair of opposite parts 41, 42 can also be shapes that extend in a direction other than the long side direction 103, for example, shapes that extend in the short side direction 102.

[0093] The pair of opposing portions 41 and 42 may not be in the shape of extending linearly in one direction (the long side direction 103 in the first embodiment).

[0094] The protrusion 40 may not be composed solely of a pair of opposing portions 41 and 42. For example, the protrusion 40 may also have a portion connecting one end 41A and 42A of the pair of opposing portions 41 and 42 to each other, in addition to the pair of opposing portions 41 and 42. In this case, when viewed from above, the protrusion 40 becomes approximately U-shaped. Alternatively, for example, the protrusion 40 may also have a portion connecting one end 41A and 42A of the pair of opposing portions 41 and 42 to each other, and a portion connecting the other end 41B and 42B to each other, in addition to the pair of opposing portions 41 and 42. In this case, when viewed from above, the protrusion 40 becomes a rectangular ring.

[0095] Figure 6 This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part. Figure 7 This is a variation of the pressure sensor element according to the first embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part.

[0096] like Figure 6 and Figure 7 As shown, the protrusion 40 can also be made of a conductive material. For example, the protrusion 40 can also be formed of the same material as the substrate-side conductive layer 22, namely polysilicon. In this case, the protrusion 40 can also be integrally formed with the substrate-side conductive layer 22.

[0097] When the protrusion 40 is conductive, the diaphragm portion 31, which flexes under pressure, may become electrically connected to the base-side conductive layer 22 via the protrusion 40. Therefore, in order to prevent the diaphragm portion 31 from becoming electrically connected to the base-side conductive layer 22, the pressure sensor element 1 with the conductive structure of the protrusion 40 also includes an insulating film 50.

[0098] exist Figure 6 In the structure shown, the protrusion 40 and Figure 1 The structure shown is similarly provided on the substrate-side conductive layer 22 (the surface of the substrate-side conductive layer 22 facing the pair of recesses 20C, 20D). In this case, the insulating film 50 is provided on the surface of the diaphragm portion 31 facing the opening 20A.

[0099] exist Figure 7 In the structure shown, the protrusion 40 and Figure 5 The structure shown is similarly provided on the diaphragm portion 31 (the surface of the diaphragm portion 31 facing the pair of recesses 20C, 20D). In this case, the insulating film 50 is provided on the surface of the substrate-side conductive layer 22 and the substrate 10 facing the opening 20A.

[0100] Furthermore, the insulating film 50 may be disposed at least in a position that prevents electrical connection between the diaphragm portion 31 and the substrate-side conductive layer 22. For example, in Figure 6 In the structure shown, the insulating film 50 is disposed on the entire surface of the diaphragm portion 31 facing the opening 20A. However, the insulating film 50 may also be disposed only on the portion of this surface opposite the protrusion 40 in the lamination direction 101. For example, in Figure 7 In the structure shown, the insulating film 50 is disposed on the surface of the substrate-side conductive layer 22 and the substrate 10 facing the opening 20A. However, the insulating film 50 may also be disposed only on the substrate-side conductive layer 22 and not on the substrate 10.

[0101] The insulating film 50 can also be provided in a manner that covers the protrusion 40.

[0102] As described above, the insulating film 50 covers at least one of the portions of the diaphragm portion 31 that come into contact with the protrusion 40 due to bending, and the protrusion 40. In the structure having the insulating film 50, the insulating film 50 exists between the diaphragm portion 31 and the protrusion 40, or between the base-side conductive layer 22 and the protrusion 40. Therefore, the diaphragm portion 31, which is prevented from bending under pressure, is electrically connected to the base-side conductive layer 22 via the protrusion 40.

[0103] according to Figure 6 and Figure 7 The structure shown allows for the integral formation of the protrusion 40 with other conductive materials, such as the base-side conductive layer 22, since the protrusion 40 is made of a conductive material. This reduces the number of manufacturing steps required for the pressure sensor element 1.

[0104] On the other hand, if the protrusion 40 is made of a conductive material, the diaphragm portion 31 may become electrically connected to the base 10 or the base-side conductive layer 22 via the protrusion 40 due to the flexing of the diaphragm portion 31. Therefore, according to Figure 6 and Figure 7 The structure shown can prevent the aforementioned electrical connections using the insulating film 50.

[0105] <Second Implementation>

[0106] Figure 8 This is a schematic top view of the portion of the pressure sensor element after the electrodes have been removed, according to the second embodiment of the present invention. The pressure sensor element 1A of the second embodiment differs from the pressure sensor element 1 of the first embodiment in that the pair of opposing portions 41, 42 of the protrusion 40 have multiple protrusions 43. Hereinafter, the differences from the first embodiment will be explained. For the commonalities with the pressure sensor element 1 of the first embodiment, descriptions will generally be omitted, using the same reference numerals, but will be provided as needed.

[0107] like Figure 8 As shown, a pair of opposing portions 41 and 42 have a plurality of protrusions 43. The plurality of protrusions 43 protrude from the fixed electrode 221 of the substrate-side conductive layer 22 toward a pair of recesses 20C and 20D along the stacking direction 101. The plurality of protrusions 43 are arranged at intervals along the long side direction 103. Thus, the plurality of protrusions 43 are generally linear along the long side direction 103.

[0108] exist Figure 8 In this case, both of the pair of opposing portions 41 and 42 have multiple protrusions 43, but it is also possible that only one of the pair of opposing portions 41 and 42 has multiple protrusions 43. Figure 8 In the middle, a pair of opposing parts 41 and 42 are each composed of a plurality of protrusions 43 in the overall range, but it is also possible that they are composed of a plurality of protrusions 43 in a local range and are formed as a line in the part other than that local range.

[0109] According to the second embodiment, a pair of opposing portions 41, 42 have a plurality of protrusions 43 arranged at intervals between each other. The plurality of protrusions 43 contact the flexible diaphragm portion 31. Therefore, compared with a structure in which the pair of opposing portions 41, 42 extend in a linear manner, the contacting diaphragm portion 31 is easier to bend. As a result, the detection accuracy of capacitance changes achieved by the bending of the diaphragm portion 31 can be improved.

[0110] <Third Implementation>

[0111] Figure 9 The pressure sensor element in the third embodiment of the present invention is related to... Figure 1A schematic end view of the corresponding part. The pressure sensor element 1B of the third embodiment differs from the pressure sensor element 1 of the first embodiment in that it also includes an inner layer 60. Hereinafter, the differences from the first embodiment will be explained. For the common points with the pressure sensor element 1 of the first embodiment, the descriptions will be omitted in principle, based on the same reference numerals, and will be explained as needed.

[0112] like Figure 9 As shown, the pressure sensor element 1B also includes an inner layer 60. The inner layer 60 is laminated on the surface of the diaphragm portion 31 on the side of the opening 20A (the lower surface of the diaphragm portion 31). The inner layer 60 is laminated on the portion of the diaphragm portion 31 located between a pair of opposing portions 41, 42 in the short side direction 102. The inner layer 60 is laminated on the portion of the surface of the diaphragm portion 31 facing the through hole 20B on the side of the opening 20A.

[0113] The inner layer 60 includes a conductive electrode-side layer 61 and an insulating electrode-side layer 62. The insulating electrode-side layer 62 is laminated on the diaphragm portion 31. The conductive electrode-side layer 61 is laminated on the side of the insulating electrode-side layer 62 opposite to the side where the diaphragm portion 31 is located. That is, the insulating electrode-side layer 62 is located between the conductive electrode-side layer 61 and the diaphragm portion 31. The conductive electrode-side layer 61 is electrically connected to the electrode 30 via a through-hole 61A that penetrates the insulating electrode-side layer 62 in the lamination direction 101.

[0114] In the third embodiment, the electrode-side conductive layer 61 is formed of polycrystalline silicon, and the electrode-side insulating layer 62 is formed of silicon dioxide. The electrode-side conductive layer 61 is not limited to polycrystalline silicon, and the material forming the electrode-side insulating layer 62 is not limited to silicon dioxide.

[0115] The electrode-side insulating layer 62 is positioned in the same direction as the second base-side insulating layer 23 of the intermediate layer 20 in the lamination direction 101. Therefore, during the manufacturing process of the pressure sensor element 1B, the lamination processes of the electrode-side insulating layer 62 and the second base-side insulating layer 23 can be performed in the same step. In the third embodiment, the electrode-side insulating layer 62 has the same thickness as the second base-side insulating layer 23, but it can also have a different thickness.

[0116] The electrode-side conductive layer 61 is positioned in the same direction as the base-side conductive layer 22 of the intermediate layer 20 in the stacking direction 101. Therefore, during the manufacturing process of the pressure sensor element 1B, the stacking process of the electrode-side conductive layer 61 and the base-side conductive layer 22 can be performed as a single process. In the third embodiment, the electrode-side conductive layer 61 has a different thickness than the base-side conductive layer 22, but it can also have the same thickness as the base-side conductive layer 22.

[0117] Figure 10This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end view of the corresponding part. For example... Figure 10 As shown, in the third embodiment, it can also be compared with the first embodiment. Figure 5 The modified example shown similarly provides a protrusion 40 on the diaphragm portion 31.

[0118] Figure 11 This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end face view of the corresponding part. Figure 12 This is a variation of the pressure sensor element in the third embodiment of the present invention. Figure 1 A schematic end view of the corresponding part. For example... Figure 11 and Figure 12 As shown, in the third embodiment, it can also be compared with the first embodiment. Figure 6 and Figure 7 The modified example shown also has an insulating film 50.

[0119] For example, in Figure 11 In the structure shown, the insulating film 50 is disposed on the surfaces of the diaphragm portion 31 and the inner layer 60 facing the opening 20A. For example, in Figure 12 In the structure shown, the insulating film 50 is disposed on the surface of the substrate-side conductive layer 22 and the substrate 10 facing the opening 20A.

[0120] According to the third embodiment, in addition to adjusting the spacing between the electrode 30 and the base 10 or the base-side conductive layer 22 by changing the thickness (length in the stacking direction 101) of the intermediate layer 20, the spacing can also be adjusted by changing the thickness of the inner layer 60. This increases the degree of freedom in adjusting the spacing.

[0121] Forming an excessively thick layer is more difficult than forming a layer of appropriate thickness. According to the third embodiment, the inner layer 60 includes an electrode-side conductive layer 61 and an electrode-side insulating layer 62. That is, the inner layer 60 has two layers. Therefore, the inner layer 60 can be made relatively thick overall without causing the individual thicknesses of the electrode-side conductive layer 61 and the electrode-side insulating layer 62 to become extremely thick. Thus, according to the third embodiment, it is easier to make the inner layer 60 thicker than a structure where the inner layer 60 is a single layer.

[0122] In the embodiments described above, an example was given where the opening 20A has a through hole 20B and a pair of recesses 20C and 20D; however, the opening 20A may also have only the through hole 20B. In this case, the side of the through hole 20B is divided by the intermediate layer 20 (the first base-side insulating layer 21, the base-side conductive layer 22, and the second base-side insulating layer 23). A protrusion 40 is provided on the base 10 (specifically, on the surface of the base 10 facing the opening 20A) instead of on the base-side conductive layer 22, protruding into the opening 20A.

[0123] In a pressure sensor element with only a through hole 20B in the opening 20A, a capacitor is formed by a diaphragm portion 31 and a base 10. The diaphragm portion 31 flexes as a membrane when not in contact with the protrusion 40. The diaphragm portion 31 flexes as multiple membranes when in contact with the protrusion 40.

[0124] The opening 20A may also not have a through hole 20B, but only a recess. In this case, the bottom surface of the recess corresponds to the bottom surface of the opening 20A. The protrusion 40 is provided on the bottom surface of the recess and protrudes into the opening 20A (the recess).

[0125] The bottom surface of the recess can be any layer in the intermediate layer 20. For example, if the bottom surface of the recess is a conductive base-side conductive layer 22, a capacitor is formed by the diaphragm portion 31 and the base-side conductive layer 22.

[0126] In the embodiments described above, examples have been given of the intermediate layer 20 comprising a first base-side insulating layer 21, a base-side conductive layer 22, and a second base-side insulating layer 23. However, the structure of the intermediate layer 20 is not limited to the structure described above. For example, the intermediate layer 20 may also be composed of a single insulating layer. In this case, for example, a capacitor may be formed by the diaphragm portion 31 and the base 10.

[0127] The pressure sensor element described above can also be described as follows.

[0128] (1) A pressure sensor element of one embodiment of the present invention comprises:

[0129] The base is conductive;

[0130] An intermediate layer, which is stacked on the base and has an opening; and

[0131] A conductive electrode, stacked on the side of the intermediate layer opposite to the side where the base is located, has a diaphragm portion that overlaps with the opening when viewed from the stacking direction. This electrode is electrically insulated from the base.

[0132] The opening has:

[0133] Through-hole, which penetrates the intermediate layer in the stacking direction; and

[0134] A pair of recesses, which are continuously disposed on the electrode-side surface of the intermediate layer, sandwiching the through hole, and are recessed along the stacking direction.

[0135] The intermediate layer includes a base-side conductive layer, which forms the bottom surface of the pair of recesses and is electrically connected to the base.

[0136] The diaphragm portion is opposite to the substrate-side conductive layer in the stacking direction, separated by the pair of recesses, and is opposite to the substrate in the stacking direction, separated by the through-hole.

[0137] The pressure sensor element further includes a protrusion disposed on the surface of at least one of the base-side conductive layer and the diaphragm portion on the side of the pair of recesses, and protruding toward the pair of recesses.

[0138] The protrusion has a pair of opposing portions that are spaced apart from each other in the direction in which the through hole is sandwiched between the pair of recesses, i.e., in the width direction.

[0139] The pair of opposing portions are positioned to overlap with the ends of the pair of recesses on the through-hole side when viewed from the stacking direction.

[0140] (2) The pressure sensor element of one embodiment of the present invention comprises:

[0141] A conductive base;

[0142] An intermediate layer, which is stacked on the base and has an opening;

[0143] A conductive electrode, stacked on the side of the intermediate layer opposite to the side where the base is located, has a diaphragm portion that overlaps with the opening when viewed from the stacking direction; this electrode is electrically insulated from the base.

[0144] A protrusion, which is disposed on the surface of at least one of the base and the diaphragm portion on the side of the opening, protrudes toward the opening.

[0145] The protrusion has a pair of opposing portions that extend along the extending direction on the surface located on the opening side, and are spaced apart from each other in a width direction intersecting the extending direction.

[0146] When viewed from the stacking direction, the region in the diaphragm portion located in the width direction between the pair of opposing portions is rectangular.

[0147] (3) In the pressure sensor element of (1),

[0148] The pair of opposing portions may extend along an extension direction intersecting the width direction.

[0149] When viewed from the stacking direction, the region in the width direction of the diaphragm portion that is located between the pair of opposing portions can be rectangular.

[0150] (4) In the pressure sensor element of (2) or (3), it can be,

[0151] The length of each of the pair of opposing portions along the extension direction is longer than the distance between the pair of opposing portions in the width direction.

[0152] (5) Among the pressure sensor elements of any one of (2) to (4), it can be,

[0153] At least one of the pair of opposing portions has a plurality of protrusions arranged at intervals along the extending direction.

[0154] (6) The pressure sensor element of any one of (1) to (5) may further include an inner layer, which is stacked on the surface of the diaphragm portion located between the pair of opposing portions in the width direction and is the surface located on the opening side.

[0155] The inner layer may have an electrode-side conductive layer that is electrically connected to the electrode.

[0156] (7) In the pressure sensor element of (6), it can be,

[0157] The inner layer also includes an insulating electrode-side insulating layer located between the electrode-side conductive layer and the diaphragm portion.

[0158] (8) Among the pressure sensor elements of any one of (1) to (7), it can be

[0159] The spacing in the width direction of the pair of opposing portions is longer than the shortest distance in the width direction between each of the pair of opposing portions and the outer edge of the opening.

[0160] (9) Among the pressure sensor elements of any one of (1) to (8),

[0161] The protrusion may be made of a conductive material.

[0162] The pressure sensor element may further include an insulating membrane that covers the portion of the diaphragm that contacts the protrusion due to the flexure of the diaphragm portion and at least one of the protrusions.

[0163] Furthermore, by appropriately combining any of the above-described embodiments, their respective effects can be achieved.

[0164] In addition, in the various embodiments described above, only a portion of the feature points of the pressure sensor element of the present invention may be included.

[0165] The following is an example.

[0166] The pressure sensor element 1 of the first embodiment has a first feature point and a second feature point. Here, the first feature point is: the opening 20A has a through hole 20B with a depth D1 and a pair of recesses 20C, 20D with a depth D2 that is shallower than the depth D1. The second feature point is: the area surrounded by four virtual straight lines LN1, LN2, LN3, LN4 when viewed from above is rectangular.

[0167] The pressure sensor element may also have a first feature point but not a second feature point. The pressure sensor element of (1) can include a pressure sensor element having a first feature point but not a second feature point.

[0168] The pressure sensor element can also, conversely, have a second feature point but not a first feature point. The pressure sensor element of (2) can include a pressure sensor element having a second feature point but not a first feature point.

[0169] Furthermore, the pressure sensor element of (3) is a pressure sensor element having both a first feature point and a second feature point.

[0170] While referring to the appendix Figure 1 The invention has been fully described in connection with preferred embodiments, but various modifications and variations will be apparent to those skilled in the art. Such modifications and variations are to be understood as included therein, provided they do not depart from the scope of the invention as defined in the appended claims.

[0171] Explanation of reference numerals in the attached figures

[0172] 1. Pressure sensor element;

[0173] 10. Abutment;

[0174] 20. Intermediate layer;

[0175] 20A, Opening;

[0176] 20B, Through hole;

[0177] 20C, concave part;

[0178] 20Ca, bottom surface;

[0179] 20D, concave part;

[0180] 20Da, bottom surface;

[0181] 20E, Top surface (the surface of the intermediate layer on the electrode side);

[0182] 22. Conductive layer on the base side;

[0183] 30. Electrode;

[0184] 31. Diaphragm section;

[0185] 40. Convex part;

[0186] 41. Relative part;

[0187] 41A, One end;

[0188] 41B, the other end;

[0189] 42. Relative part;

[0190] 42A, one end;

[0191] 42B, the other end;

[0192] 43. Protrusion;

[0193] 50. Insulating film;

[0194] 60. Inner layer;

[0195] 61. Conductive layer on the electrode side;

[0196] 62. Electrode-side insulating layer;

[0197] 101. Stacking direction;

[0198] 102. Short side direction (width direction);

[0199] 103. Long side direction (extension direction);

[0200] LN1, virtual line;

[0201] LN2, virtual line;

[0202] LN3, Virtual Line;

[0203] LN4, Virtual Line.

Claims

1. A pressure sensor element, wherein the pressure sensor element comprises: a base having electrical conductivity; an intermediate layer laminated to the base and having an opening portion; and an electrode having electrical conductivity laminated to a side of the intermediate layer opposite the side on which the base is present, the electrode having a diaphragm portion overlapping the opening portion when viewed in a lamination direction, the electrode being electrically insulated from the base, the opening portion has: a through-hole passing through the intermediate layer in the lamination direction; and a pair of recessed portions provided continuously with the through-hole in the intermediate layer on a side of the electrode, recessed in the lamination direction, the intermediate layer comprises a base-side conductive layer constituting a bottom surface of the pair of recessed portions and electrically connected to the base, the diaphragm portion opposes the base-side conductive layer in the lamination direction with the pair of recessed portions interposed therebetween, and opposes the base in the lamination direction with the through-hole interposed therebetween, the pressure sensor element further comprises a protrusion provided on a surface of at least one of the base-side conductive layer and the diaphragm portion on a side of the pair of recessed portions and protruding toward the pair of recessed portions, the protrusion comprises a pair of opposing portions opposite each other in a width direction in which the pair of recessed portions sandwich the through-hole, the pair of opposing portions are positioned to overlap end portions of the pair of recessed portions on a side of the through-hole when viewed in the lamination direction.

2. A pressure sensor element, wherein the pressure sensor element comprises: a base having electrical conductivity; an intermediate layer laminated to the base and having an opening portion; an electrode having electrical conductivity laminated to a side of the intermediate layer opposite the side on which the base is present, the electrode having a diaphragm portion overlapping the opening portion when viewed in a lamination direction, the electrode being electrically insulated from the base; and a protrusion provided on a surface of at least one of the base and the diaphragm portion on a side of the opening portion and protruding toward the opening portion, the protrusion comprises a pair of opposing portions each extending on the surface on a side of the opening portion along an extension direction and opposite each other in a width direction intersecting the extension direction, a region between the pair of opposing portions in the width direction in the diaphragm portion is rectangular when viewed in the lamination direction.

3. The pressure sensor element according to claim 1, wherein the pair of opposing portions extend along an extension direction intersecting the width direction, a region between the pair of opposing portions in the width direction in the diaphragm portion is rectangular when viewed in the lamination direction.

4. The pressure sensor element according to claim 2 or 3, wherein a length of each of the pair of opposing portions along the extension direction is longer than a spacing in the width direction of the pair of opposing portions.

5. The pressure sensor element according to any one of claims 2 to 4, wherein at least one of the pair of opposing portions comprises a plurality of protrusions arranged apart from each other along the extension direction.

6. The pressure sensor element according to any one of claims 1 to 5, wherein The pressure sensor element also has an inner layer that is laminated to a surface in the diaphragm portion that is between the pair of opposing portions in the width direction and that is on the opening portion side, The inner layer has an electrode-side conductive layer that is electrically connected to the electrode and that has electrical conductivity.

7. The pressure sensor element according to claim 6, wherein The inner layer also has an electrode-side insulating layer that is between the electrode-side conductive layer and the diaphragm portion and that has insulating properties.

8. The pressure sensor element according to any one of claims 1 to 7, wherein The interval of the pair of opposing portions in the width direction is longer than the shortest distance in the width direction between each of the pair of opposing portions and the outer edge of the opening portion.

9. The pressure sensor element according to any one of claims 1 to 8, wherein The protruding portion is composed of a material that has electrical conductivity, The pressure sensor element also has an insulating film that has insulating properties, the insulating film covering at least one of the portion that is in contact with the protruding portion due to the diaphragm portion flexing and the protruding portion.

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