Piezoelectric resonance device

Abstract

To provide a piezoelectric resonance device in which resonance frequency of a piezoelectric element can vary depending on a variety of factors.SOLUTION: A piezoelectric resonance device includes: a substrate 110 having a first surface 1110; a first connection conductor located on the first surface; a MEMS element 150 which is located on the first surface and has a second surface (a top surface 1500), a second connection conductor 151 located on the second surface and a resonance part 153 exposed on the second surface and electrically connected to the second connection conductor; and a wiring conductor (a bonding wire 181) electrically connecting the first connection conductor and the second connection conductor. The first connection conductor, the second connection conductor and the wiring conductor are located outside a range where a range of the resonance part is made to extend in a prescribed direction in a planar view looking at the first surface from above.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present disclosure relates to piezoelectric resonant devices. [Background technology]

[0002] In recent years, piezoelectric resonant devices, which output signals by vibrating a piezoelectric element at a resonant frequency, have developed a technology that uses MEMS (Micro Electro Mechanical Systems) structure elements (MEMS elements) that use semiconductor elements such as silicon instead of quartz.

[0003] The resonant frequency of a piezoelectric element can change depending on various factors. For example, as shown in Patent Document 1, there is a piezoelectric vibration device in which a shield that reduces the influence of external noise is appropriately positioned. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-97105 Summary of the Invention [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate having a first surface; a first connecting conductor located on the first surface; a MEMS element located on the first surface, the MEMS element having a second surface, a second connecting conductor located on the second surface, and a resonator portion exposed on the second surface and electrically connected to the second connecting conductor; a wiring conductor that electrically connects the first connecting conductor and the second connecting conductor; Equipped with the first connecting conductor, the second connecting conductor, and the wiring conductor are located outside a range obtained by extending the range of the resonator in a predetermined direction in a plan view of the first surface from above; It is a piezoelectric resonant device. [Brief explanation of the drawings]

[0006] [Figure 1A] 1 is an overall perspective view of a piezoelectric resonant device with the lid removed, showing the side to which the lid is connected. FIG. [Figure 1B] 1 is an overall perspective view of a piezoelectric resonant device with the lid removed, viewed from the side opposite to the side to which the lid is connected. FIG. [Figure 2A] FIG. 2 is a plan view of the piezoelectric resonant device with the cover removed. [Figure 2B] 1 is a cross-sectional view of a piezoelectric resonator device with a cover removed. [Figure 3] 3 is a cross-sectional view illustrating in more detail the MEMS element including the resonator portion. FIG. [Figure 4A] FIG. 10 is a cross-sectional view showing a first modified example of the piezoelectric resonant device. [Figure 4B] FIG. 10 is a cross-sectional view showing a second modified example of the piezoelectric resonant device. [Figure 4C] FIG. 10 is a cross-sectional view showing a third modified example of the piezoelectric resonant device. [Figure 5A] FIG. 10 is a cross-sectional view showing a fourth modified example of the piezoelectric resonant device. [Figure 5B] FIG. 10 is a cross-sectional view showing a fifth modified example of the piezoelectric resonant device. [Figure 6] 13 is a plan view showing a state in which the cover is removed in a sixth modification of the piezoelectric resonant device. FIG. [Figure 7] FIG. 13 is an overall perspective view of a seventh variation of the piezoelectric resonant device with the cover removed. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment will be described with reference to the drawings. 1A and 1B are overall perspective views of the piezoelectric resonant device 1 of this embodiment, with the lid 120 removed. Fig. 1A is a view of the surface to which the lid 120 is joined, and Fig. 1B is a view of the surface opposite to the surface to which the lid 120 is joined.

[0008] The piezoelectric resonant device 1 includes a base 100, a MEMS element 150, and the like. The base 100 includes a substrate 110, a lid 120, and the like. The substrate 110 is divided into a frame portion 1101 and a base portion 1102, and includes a housing portion 111, a through-hole 115, and the like. Also, a frame-shaped metallized layer 112, electrode pads 113, external connection pads 114, and the like are bonded to the substrate 110. The housing portion 111 is a concave region located on one surface to which the lid 120 is bonded, i.e., on the upper surface in the z direction. The MEMS element 150 is located within the housing portion 111. The frame 1101 is the side surface of the accommodation section 111 other than the upper open surface and the mounting surface 1110 (first surface) for the MEMS element 150, which is the surface opposite the open surface, i.e., the surfaces connecting the open surface and the mounting surface 1110, and here each form a surface parallel to the z direction. The base 1102 is the portion of the substrate 110 below the accommodation section 111 and the frame 1101, i.e., in the -z direction, and includes the mounting surface 1110. A frame-shaped metallization layer 112, which is a conductive layer, is located in a frame shape on the bonding surface of the frame 1101 with the lid 120 (the end surface on the open surface side). The frame-shaped metallization layer 112 is bonded to the lid 120 via a sealing material such as silver solder. Although not particularly limited, the size of the substrate 110 is about 0.6 to 10.0 mm on a side in the xy plane, and about 0.2 to 2.0 mm in thickness in the z direction. Here, the x direction is the longitudinal direction of the base 100.

[0009] A pair of electrode pads 113 (first connection conductors) are positioned side by side in the y direction on the mounting surface 1110 of the accommodating section 111. The electrode pads 113 are, for example, rectangular and have the same size and orientation in a plan view. The electrode pads 113 are connected to external connection pads 114, for example, external connection pads 1141 and 1144. The electrode pads 113 are formed, for example, by plating a gold thin film layer on the mounting surface 1110. Alternatively, the electrode pads 113 may be formed in a convex shape from the mounting surface by screen printing or the like.

[0010] The external connection pads 114 are external electrodes that are bonded to an external device, such as a module substrate. Here, the external connection pads 114 are located at the four corners of the bottom surface of the substrate, which is opposite the mounting surface 1110 of the base 1102. If the required number of external connection pads 114 is less than four, some of the external connection pads 114 may be omitted as appropriate. The external connection pads 114 connected to the MEMS element 150 may be connected to, for example, a drive circuit, and may be used as an oscillator by applying a voltage signal of a predetermined frequency to the MEMS element 150.

[0011] The MEMS element 150 is located on the mounting surface 1110 of the housing portion 111 in the -x direction relative to the electrode pads 113. The MEMS element 150 is bonded to the mounting surface 1110 via an adhesive member 170. The adhesive member 170 is, for example, a resin-based adhesive and has insulating properties. The adhesive member 170 may be made of an epoxy-based resin containing alumina or the like. The particle size of the filler in the adhesive member 170 is, for example, 1 to 10 μm. This allows the MEMS element 150 to be stably mounted without tilting.

[0012] The MEMS element 150 is electrically connected to two electrode pads 1131 (third connection portion) and 1132 (fourth connection portion) via two conductive bonding wires 181 (first wiring conductor) and 182 (second wiring conductor), respectively. The bonding wires 181 and 182 are collectively referred to as bonding wires 180 (wiring conductors). The material of the bonding wire 180 is not particularly limited, but may be gold (Au), for example. The bonding of the bonding wire 180 is performed by ultrasonic bonding using, for example, a wire bonder with a capillary. Here, the bonding of the bonding wire 180 to the MEMS element 150 is the first bonding, and the bonding of the bonding wire 180 to the electrode pad 113 is the second bonding. However, the order of bonding can be reversed to reduce the pressure applied to the MEMS element 150 during ultrasonic bonding.

[0013] The substrate 110 includes a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass-ceramic sintered body. The lid 120 is made of a conductive metal and is bonded to the frame-shaped metallization layer 112 to hermetically seal the housing portion 111. A conductive sealing material such as gold-tin (AuSn) or silver solder is used for sealing. The lid 120 is grounded to suppress transmission of external noise into the housing portion 111. The lid 120 is electrically connected to the through-holes 115 of the substrate 110 via the conductive sealing material and the frame-shaped metallization layer 112. The through-holes 115 penetrate the substrate 110 in the z-direction and are connected to one or two of the external connection pads 114 on the bottom surface of the substrate. The lid 120 is grounded by grounding the external connection pads 114. The frame 1101 may have a plate-shaped conductive plate instead of the through-hole 115, and may form part of a path that electrically connects the lid 120 and the external connection pad 114.

[0014] The frame-shaped metallized layer 112 is made of a conductive metal and is formed by printing on the joining surface of the frame portion 1101 . At least the exposed surfaces of the conductive portions, such as the frame-shaped metallization layer 112, the electrode pads 113, and the external connection pads 114, may be coated with a nickel and / or gold plating layer. For example, the exposed surfaces may be nickel-plated to a thickness of 1 to 20 μm, and then a gold plating layer may be formed on the nickel-plated layer to a thickness of 0.1 to 3.0 μm. This prevents oxidation and corrosion of the surface and facilitates a strong connection between the frame-shaped metallization layer 112, located on the upper surface of the insulating substrate 110, and the metal conductor lid 120. Furthermore, the metallization layer 112 can be properly connected to the gold bonding wire 180, allowing signals to be transmitted with low resistance.

[0015] Fig. 2A is a plan view of the piezoelectric resonant device 1 with the cover 120 removed. Fig. 2B is a cross-sectional view taken along the line AA in the plan view of Fig. 2A.

[0016] As described above, the two electrode pads 1131 and 1132 are located side by side in the y direction near the end of the mounting surface 1110 where the x component is greatest. The electrode pads 1131 and 1132 are located approximately symmetrically with respect to the center line Sy of the substrate 110 in the y direction. The connection point C3 between the electrode pad 1131 and the bonding wire 181 and the connection point C4 between the electrode pad 1132 and the bonding wire 182 are also located at approximately the same position in the x direction. That is, the second reference line S2 passing through the connection points C3 and C4 is parallel to the y axis, and the midpoint between the connection points C3 and C4 approximately overlaps the center line Sy. Here, the connection point C3 is defined as a predetermined third position of the electrode pad 1131. The connection point C4 is defined as a predetermined fourth position of the electrode pad 1132. Note that the expressions "parallel," "points overlapping each other or a point and a line overlapping each other," and "identical" used here and hereafter do not necessarily have to be precise. Some deviation from the designed position may be allowed.

[0017] The base 1102 has through conductors 1161 and 1162 that penetrate the base 1102 at positions that overlap the electrode pads 1131 and 1132 in a plan view. The through conductors 1161 and 1162 have a first end and a second end. The first ends are connected to the electrode pads 1131 and 1132, and the second ends are connected to the external connection pads 1141 and 1144. Note that although the through conductors 1161 and 1162 have been described here as extending only in the z-direction, they may also extend in the xy-plane directions within the base 1102 to connect, for example, the electrode pad 1131 to the external connection pad 1142.

[0018] The MEMS element 150 includes a connection pad 151 (first connection portion) and a connection pad 152 (second connection portion) on its upper surface (second surface), i.e., the surface opposite to the surface bonded to the mounting surface by the adhesive member 170, and a resonating unit 153. The resonating unit 153 has a resonating means 1531. The upper surface of the resonating means 1531 is exposed on the upper surface (second surface) of the MEMS element 150, is supported by a node, and is capable of vibrating in a predetermined mode with the node as a fixed end. The resonating means 1531 has an upper electrode and a lower electrode on its upper surface side, i.e., the +z side, and its lower surface side, i.e., the -z side, as described below, and each electrode is electrically connected to the connection pads 151 and 152. Here, the connection pad 151 is connected to the upper electrode via a wiring 154. The connection pad 152 is connected to the lower electrode inside the MEMS element 150.

[0019] The connection pads 151 and 152 are located near the end of the MEMS element 150 where the x component is largest, and are collectively referred to as a second connection conductor. The connection pads 151 and 152 are connection ends of the MEMS element 150 that are connected to the electrode pads 1131 and 1132 by the bonding wire 180 as described above. The top surfaces of the connection pads 151 and 152 may be made of gold (Au), for example. The connection pad 151 is located at a position corresponding to the electrode pad 1131 in the y direction, between the electrode pad 1131 and the resonator unit 153, and is connected to the bonding wire 181. The connection pad 152 is located at a position corresponding to the electrode pad 1132 in the y direction, between the electrode pad 1132 and the resonator unit 153, and is connected to the bonding wire 182. The connection points C1 and C2 of the bonding wires 181 and 182 on the connection pads 151 and 152 are located at approximately the same position in the x direction and are located approximately symmetrically with respect to the center line Sy in the y direction. That is, a first reference line S1 passing through the connection points C1 and C2 is parallel to the y axis, and the midpoints of these connection points C1 and C2 almost coincide with the center line Sy. The y coordinates of the connection points C1 and C3 are also approximately the same, and the y coordinates of the connection points C2 and C4 are also approximately the same. Therefore, the bonding wire 181, i.e., the line connecting the connection points C1 and C3, and the bonding wire 182, i.e., the line connecting the connection points C2 and C4, extend parallel to the x direction in a plan view, i.e., perpendicular to the y direction. Here, the connection point C1 is defined as a predetermined first position of the connection pad 151, and the connection point C2 is defined as a predetermined second position of the connection pad 152. The bonding wires 181, 182 do not need to extend the shortest distance in the x direction, i.e., in a straight line, and may have some slack, or may be slightly deviated or bent in the y direction from a straight line extending in the x direction in a plan view, but do not have more slack than necessary. Here, the bonding wires 181, 182 are designed not to hang down and come into contact with the upper edge of the MEMS element 150.

[0020] Here, the center position or center of gravity of the resonator 153 is located on the center line Sy, so that the resonator 153, the connection pads 151 and 152, the bonding wires 181 and 182, and the electrode pads 1131 and 1132 are all symmetrical with respect to the center line Sy.

[0021] The MEMS element 150 is, for example, rectangular in shape with its longitudinal direction aligned with the x-direction, which is the longitudinal direction of the base 100, but is not limited to this. The shape of the resonating unit 153 can vary depending on the output frequency, etc., and the resonating unit 153 may be positioned in an optimal orientation depending on the shape. On the top surface of the MEMS element 150, near the edge (position) in the -x direction that does not overlap with the resonating unit 153, i.e., on the opposite side of the resonating unit 153 from the connection pads 151 and 152, there is a small space 155. This space 155 is used as a suction space for a suction device that suctions and holds the MEMS element 150 when the MEMS element 150 is placed and mounted on a mounting surface. The size of space 155 need only be a predetermined area or more that allows the suction device to suction MEMS element 150, within the range of suction force that is not too strong and will damage MEMS element 150, and may be, for example, 100 μm in the x direction and a length less than the width of MEMS element 150 in the y direction, for example, 450 μm for a MEMS element 150 with a width of 600 to 800 μm. Space 155 need only be a flat surface that can be attached to the top surface of MEMS element 150, and may have written thereon, for example, a product serial number or the like.

[0022] The adhesive member 170 is not only bonded to the backside of the MEMS element 150 on the surface facing the mounting surface 1110, but also extends outward beyond the outer edge of the MEMS element 150 in a plan view. For example, when the bonding wires 181 and 182 are bonded at the connection points C1 and C2, respectively, by the first bond, a large force is applied to the MEMS element 150 from above. However, since the entire MEMS element 150 is stably bonded and fixed at this time, the elasticity of the adhesive member 170 absorbs the force in a balanced manner, preventing damage to the MEMS element 150. The adhesive member 170 may be attached to the entire surface of the MEMS element 150 facing the mounting surface 1110, or the opposing surface may include some portions to which the adhesive member 170 is not attached.

[0023] Furthermore, the connection points C1 and C3 are determined so that the distance L1 between the connection points C1 and C3 (each connection position) in a plan view is smaller than the distance L2 between the connection point C3 and the edge of the mounting surface 1110 in the +x direction, i.e., the frame portion 1101. Since the connection points C1 and C2 are positioned at the same position in the x direction and the connection points C3 and C4 are positioned at the same position in the x direction, in this case, similarly, the distance L1 between the connection points C2 and C4 (each connection position) is equal to the distance between the connection points C1 and C3. Furthermore, the distance L2 is the distance from the connection point C4 to the frame portion 1101 in the +x direction. Since the bonding wires 181 and 182 are fed out to approximately the same length by the wire bonder, the lengths of the bonding wires 181 and 182 are also approximately equal. In this way, by making the lengths of the bonding wires 181 and 182 equal and not longer than necessary, it is possible to transmit signals evenly and with low loss in the bonding wires, which are thinner than other parts and tend to have larger losses.

[0024] 3 is a cross-sectional view illustrating in more detail the MEMS element 150 including the resonating portion 153. Here, a cross section taken along the cross-sectional line BB in FIG. 2A is shown.

[0025] The MEMS element 150 includes, in order from the -z side, a handling layer 1501, an insulating layer 1502, a doped layer 1503 (lower electrode), a piezoelectric layer 1504 (piezoelectric material), and an upper electrode 1505 stacked thereon.

[0026] The handling layer 1501 includes a silicon substrate and is bonded to the mounting surface 1110 of the substrate 110 by an adhesive member 170. The adhesive member 170 extends beyond the edge of the handling layer 1501, forming fillet portions 1701 and 1702.

[0027] The insulating layer 1502 is a silicon dioxide (SiO2) layer. The insulating layer 1502 may have a very small thickness. This insulating layer 1502 is removed in the range of the resonator 153. Here, the handling layer 1501 and the insulating layer 1502 are collectively referred to as a semiconductor substrate.

[0028] The doped layer 1503 is a silicon layer that has been doped with P-type doping. The doping amount here is much greater than the doping amount in a typical semiconductor device, for example, by one to two orders of magnitude. As a result, the doped layer 1503 behaves as a conductor and functions as a bottom electrode.

[0029] A portion of the doped layer 1503 other than the node is isolated from other components and is capable of vibrating.

[0030] The piezoelectric layer 1504 is a thin film layer of a piezoelectric material that has a correspondence between a physical change in shape and an electrical signal. In this example, the piezoelectric layer 1504 is a thin film layer of aluminum nitride (AlN), which deforms in response to a voltage applied between the upper electrode 1505 and the doped layer 1503, or generates a voltage between the upper electrode 1505 and the doped layer 1503 in response to the amount of deformation due to external pressure or the like.

[0031] The upper electrode 1505 is located in contact with the upper side of the piezoelectric layer 1504, and is electrically connected to the connection pad 151 via the wiring 154. The upper electrode 1505 is, for example, an aluminum (Al) layer.

[0032] In this way, the laminated structure of the doped layer 1503, the piezoelectric layer 1504, and the upper electrode 1505 is separated from the underlying handling layer 1501 in the range of the resonator 153 that does not have the insulating layer 1502, and is also separated from the periphery of each layer in the xy plane in a plan view except for node portions not shown, thereby forming resonator means 1531. This allows the resonator means 1531 to generate vibrations at a resonant frequency.

[0033] The adhesive member 170 includes, for example, an epoxy resin. The upper end positions of the fillet portions 1701 and 1702 of the adhesive member 170 are lower than the upper end position of the insulating layer 1502 (the lower end position of the doped layer 1503) on the side surface of the MEMS element 150, i.e., on a plane perpendicular to the xy plane, and are usually lower than the upper end position of the handling layer 1501. The adhesive member 170 does not contact the doped layer 1503, the piezoelectric layer 1504, or the upper electrode 1505, nor does it contact the upper surface of the MEMS element 150.

[0034] When adhesive member 170 is made of epoxy resin, if adhesive member 170 comes into contact with doped layer 1503, sodium (Na), iron (Fe) contained in the epoxy resin, and manganese (Mn), nickel (Ni), titanium (Ti), phosphorus (P), etc. that may also be contained as impurities, may migrate to doped layer 1503, causing a change in conductivity.

[0035] Furthermore, the environment in which the piezoelectric resonant device 1 is used may not be constant. When the temperature of the piezoelectric resonant device 1, i.e., the MEMS element 150, changes, the adhesive member 170 expands / contracts. If the adhesive member 170 is in contact with the doped layer 1503, the piezoelectric layer 1504, or the upper electrode 1505, the expansion / contraction of the adhesive member 170 applies unnecessary stress to the doped layer 1503, the piezoelectric layer 1504, or the upper electrode 1505, causing a change in frequency characteristics.

[0036] On the other hand, adhesive member 170 has fillet portions 1701 and 1702 and is adhered to the side surface of handling layer 1501 of MEMS element 150, thereby improving the adhesive strength of MEMS element 150.

[0037] Therefore, in the piezoelectric resonant device 1, the upper ends of the fillet portions 1701, 1702 of the adhesive member 170 are positioned so that they do not come into contact with the doped layer 1503, thereby fixing the MEMS element 150 to the mounting surface 1110 while reducing changes in the conductivity and frequency characteristics of the MEMS element 150.

[0038] The resonant frequency of the resonant means 1531 depends not only on the characteristics of the piezoelectric layer 1504 but also on the characteristics of each component, such as the size (i.e., area and thickness) of the doped layer 1503 and the upper electrode 1505, and the surrounding node members (not shown). In other words, the resonant frequency is determined only after the MEMS element 150 is mounted on the piezoelectric resonant device 1. Depending on the mounting state, the resonant frequency may deviate slightly from the expected resonant frequency. Therefore, in the piezoelectric resonant device 1, the resonant means 1531 is adjusted to approach the desired resonant frequency by thinning the exposed upper surface of the upper electrode 1505 after mounting.

[0039] In the piezoelectric resonant device 1, the surface is processed using an ion laser, such as an argon laser, to adjust the thickness of the upper electrode 1505 to be thinner than when it was mounted, thereby changing the resonant frequency. The ion laser is scanned in a predetermined direction, in this case, the scanning direction Ss, to uniformly thin the upper electrode 1505. Therefore, if the bonding wire 180 and / or the connection pads 151 and 152 are located on an extension of the scanning direction Ss, they may be scraped off and damaged. Therefore, in the piezoelectric resonant device 1, the positional relationship of each component is determined so that the bonding wire 180 or the connection pad 151 is not located on the scanning line.

[0040] The scanning direction Ss should have the same range passing through the resonator 1531 between scans. Generally, the scanning direction Ss is determined along the longitudinal direction of the resonator unit 153, which is rectangular in plan view. However, this is not limiting. The scanning direction Ss may be perpendicular to the longitudinal direction or tilted at a predetermined angle relative to the longitudinal direction. Here, as shown in FIGS. 1A, 1B, 2A, and 2B, the connection pads 151 and 152 (here, the connection points C1 and C2) are aligned in the y direction near the end of the MEMS element 150 where the x component is largest, and the resonator unit 153 is located at a position where the x component is smaller than these. That is, by determining the scanning direction Ss along the y direction, the scanning direction Ss becomes parallel to the alignment direction of the connection pads 151 and 152, i.e., the connection points C1 and C2. Therefore, the scanning line that runs multiple times across the width of the resonator unit 1531 in the x direction while shifting the scanning position on the resonator unit 153 in the x direction does not overlap the connection pads 151 and 152 in plan view. The resonating unit 153 has a longitudinal direction in the y direction.

[0041] Furthermore, the electrode pads 1131 and 1132, here connection points C3 and C4, are aligned in the y direction at a position where the x component is larger than that of the MEMS element 150. That is, the scanning direction Ss is also parallel to the alignment direction of the electrode pads 1131 and 1132, here connection points C3 and C4. Therefore, the electrode pads 1131 and 1132 do not overlap the scanning line in a planar view. Furthermore, the bonding wire 181 connecting the electrode pad 1131 and the connection pad 151 and the bonding wire 182 connecting the electrode pad 1132 and the connection pad 152 are also positioned so as not to overlap the scanning line in a planar view.

[0042] In other words, the connection pads 151 and 152, the electrode pads 1131 and 1132, and the bonding wires 181 and 182 are all located outside the range of the resonator 153 extended in the scanning direction.

[0043] The procedure for obtaining the piezoelectric resonant device 1 from the above-described base 100 and MEMS element 150 is as follows: First, an adhesive material 170 is applied to the base 100 at the mounting position of the MEMS element 150. The MEMS element 150, which has been adsorbed by an adsorption device, is moved to the mounting position of the MEMS element 150, and the MEMS element 150 is bonded to the mounting surface 1110 by pressing or the like.

[0044] A bonding wire 181 is bonded between the connection pad 151 and the electrode pad 1131, and a bonding wire 182 is bonded between the connection pad 152 and the electrode pad 1132 by a wire bonder.

[0045] While monitoring the voltage between the connection pads 151 and 152, or between the electrode pads 1131 and 1132, or between the external connection pads 1141 and 1144, the ion gun is scanned to scrape the surface of the resonator 153, thereby adjusting the resonant frequency. This adjustment may be repeated multiple times. After the adjustment is completed, the lid 120 and the frame-shaped metallized layer 112 are joined together.

[0046] 4A to 4C are cross-sectional views showing first to third modifications of the piezoelectric resonant device 1. These cross sections are the same as the cross section shown in FIG.

[0047] In the piezoelectric resonant devices 1 of Modifications 1 to 3, resin members 185, 185a, and 185b are located at least partially between the mounting surface 1110 and the bonding wires 181 and 182 that are located between the connection pads 151 and 152 of the MEMS element 150 and the electrode pads 113 of the base 100 in the x direction. The resin member 185 in the piezoelectric resonant device 1 of Modification 1 shown in FIG. 4A occupies the entire space between the connection pad 151 and the electrode pad 1131 in the x direction. In the ranges that overlap with the bonding wires 181 and 182 in plan view, the height of the resin member 185 in the z direction, i.e., the maximum distance from the mounting surface 1110, is equal to or greater than the height of the connection pads 151 and 152 of the MEMS element 150 in the z direction, and the resin member 185 contacts or covers the edge of the MEMS element 150. Gold, which is the material of bonding wire 181, is easily damaged by contact with sharp objects, so it is preferable to maintain the wiring position so that it does not come into contact with the edge of MEMS element 150. Bonding wire 181 may be in contact with resin member 185, but does not have to be in contact. In this case, bonding wire 181 can be bonded after resin member 185 is provided on base 100.

[0048] The resin members 185 to 185b may be selected, for example, from epoxy resin or polyimide resin, taking into consideration some or all of durability, volatility, and corrosion resistance, etc., as long as they do not damage the bonding wires 181 and 182. Alternatively, they may be made of any other insulating material that is more elastic than ceramic materials and does not interfere with signal transmission.

[0049] 4B shows a piezoelectric resonator device 1 according to Modification 2, in which at least a portion of the bonding wire 181 is located inside the resin member 185a. Here, the bonded portion of the bonding wire 181 to the electrode pad 1131 is also located inside the resin member 185a, but this is not limited to this. Also, contrary to the above embodiment, the connection of the bonding wire 181 to the electrode pad 1131 is shown as the first bonding, and the connection to the connection pad 151 is shown as the second bonding, but this is not limited to this. In this case, the resin member 185a may be provided on the substrate after the bonding wire 181 is bonded to the electrode pad 1131 and the connection pad 151. Alternatively, instead of embedding the bonding wire 181 inside the resin member 185a, the resin member 185a may have a groove that opens upward, that is, in the +z direction, and the bonding wire 181 may extend inside the groove.

[0050] In the piezoelectric resonant device 1 of Modification 3 shown in FIG. 4C , the resin member 185b occupies only a portion between the electrode pad 113 and the connection pad 151 that is in contact with the MEMS element 150. The height of the resin member 185b in the z direction is greater than the height of the MEMS element 150. The resin member 185b has a gentle curve near its upper end in the z direction. Similar to the resin member 185 in Modification 1, the resin member 185b is positioned and shaped to prevent the edge of the MEMS element 150 from coming into contact with the bonding wire 181. That is, even if the bonding wire 181 loosens slightly, the bonding wire 181 comes into contact with the resin member 185 near its upper end, and is therefore unlikely to come into contact with the edge of the MEMS element 150.

[0051] 5A and 5B are cross-sectional views showing modifications 4 and 5, respectively, of the piezoelectric resonant device 1. These cross sections are also taken along the same cross-sectional line AA as the cross section shown in FIG. 2B, but the cross section including the connection position of the bonding wire 182 to the electrode pad 1132 and the connection position of the bonding wire 182 to the connection pad 152 also has the same structure. In the piezoelectric resonant device 1 of Modification 4 shown in FIG. 5A, the mounting surface 1110 of the housing 111 has a protrusion 1111 perpendicular to the mounting surface 1110, and an electrode pad 1131 is located on the protrusion 1111. The electrode pad 113 on the protrusion 1111 may have a base layer (not shown) made of various well-known materials, such as nickel (Ni) or chromium (Cr), between the protrusion 1111 and the Au thin film. The protrusion is formed, for example, using a mold. That is, the mold used to form the base 1102 may include the protrusion shape.

[0052] Here, the electrode pad 113 and the surface of the connection pad 151 are located at approximately the same distance from the mounting surface 1110. That is, the heights of the connection positions of the bonding wire 181 with the electrode pad 113 and the connection pad 151 are approximately the same. This makes it easier to crimp and fix the bonding wire 181 using a wire bonder. Also, the bonding wire 181 is shortened by the amount that the length of the bonding wire 181 in the z direction is reduced. Also, the bonding wire 181 is less likely to slacken to a height at which it hits a corner of the MEMS element 150.

[0053] Even in this case, a resin member may be provided at the corner of the MEMS element 150. In this case, since there is a possibility that the bonding wire 180 may come into contact with the corner of the electrode pad 113 to the same extent as with the MEMS element 150, a resin member may also be provided at the corner of the electrode pad 113 on the MEMS element 150 side, i.e., the -x side.

[0054] 5B, the corners of the MEMS element 150a in the direction in which the bonding wire 181 extends are chamfered or rounded. This reduces damage caused by the right-angled corners even if the bonding wire 181 becomes loose and comes into contact with the MEMS element 150a. The same applies to the bonding wire 182.

[0055] In this case, too, a resin member may be provided on the mounting surface 1110. The electrode pads 113 may be located on the protrusions. Furthermore, the corners of the electrode pads 113 facing the MEMS element 150, i.e., the corners in the -x direction, may be chamfered or rounded.

[0056] FIG. 6 is a plan view showing a sixth modification of the piezoelectric resonant device 1 with the cover 120 removed.

[0057] In the piezoelectric resonant device 1 of the sixth modification, the adhesive members 171a to 171d that join the MEMS element 150 to the mounting surface extend outside the area of ​​the MEMS element 150 only at the four corners of the MEMS element 150. In other words, the adhesive members do not necessarily extend in a fillet shape from all sides of the MEMS element 150 like the adhesive member 170 in the above embodiment; as long as they extend outward at least at each corner, the MEMS element 150 can be stably and flexibly fixed.

[0058] Again, the adhesive material does not need to cover the entire area between the MEMS element 150 and the mounting surface, but in addition to the four corners, it may also be attached to, for example, connection pads 151 and 152, particularly positions overlapping connection points C1 and C2.

[0059] FIG. 7 is an overall perspective view of the seventh modification of the piezoelectric resonant device 1 with the cover 120 removed.

[0060] In the piezoelectric resonant device 1 of the seventh modification, the base 100a has a flat substrate 110a and a lid 120a having a recessed housing portion 121. In this case, the frame-shaped metallization layer 112 may be formed first on a portion of the lid 120a that corresponds to the frame of the housing portion 121, and then bonded to the substrate 110a. The electrode pads 113, bonding wires 180, and MEMS element 150 on the substrate 110a are all contained within the housing portion 121.

[0061] As described above, the piezoelectric resonant device 1 of this embodiment includes the base 100 having the mounting surface 1110, the electrode pads 1131 and 1132 located on the mounting surface 1110, the MEMS element 150 located on the mounting surface 1110 and having the upper surface 1500, the connection pads 151 and 152 located on the upper surface 1500, and the resonant unit 153 exposed on the upper surface 1500 and electrically connected to the connection pads 151 and 152, and the bonding wires 181 and 182 electrically connecting the electrode pads 1131 and 1132 to the connection pads 151 and 152. In a plan view of the mounting surface 1110 seen from above, the electrode pads 1131 and 1132, the connection pads 151 and 152, and the bonding wires 181 and 182 are located outside the range of the resonant unit 153 extended in the scanning direction of the ion gun during adjustment. In the piezoelectric resonant device 1 using the MEMS element 150, the resonant unit 153 is positioned so as to be exposed on the upper surface 1500 of the MEMS element 150. This allows the resonant frequency of the resonant unit 153 to be adjusted to a desired value according to the mounting conditions after the mounting of the resonant unit 153 more easily and accurately than with a quartz resonator, etc. In this case, the connection pads 151 and 152 can be easily connected to the electrode pads 1131 and 1132 by wire bonding in the piezoelectric resonant device 1. Furthermore, when an ion gun is used to scan the exposed surface of the resonant unit 153 and scrape the surface to adjust the thickness, the output of the ion gun is likely to damage the bonding wires 181 and 182, the electrode pads 1131 and 1132, and the connection pads 151 and 152. To prevent this damage and / or to facilitate control of an ion gun or the like for preventing damage, the piezoelectric resonant device 1 may be arranged and shaped so that the bonding wires 181, 182, the electrode pads 1131, 1132, and the connection pads 151, 152 are all located outside the range of the resonant portion 153 extended in the scanning direction. With this structure, the piezoelectric resonant device 1 can easily adjust the resonant frequency.

[0062] Furthermore, the connection pads 151 and 152 are located between the electrode pad 113 and the resonator unit 153. In this order, the bonding wire 180 is not located in a range where the x component is smaller than that of the connection pads 151 and 152 (i.e., the resonator unit 153, etc.), so that the bonding wire 180 can safely and efficiently connect the connection pads 151 and 152 to the electrode pad 113.

[0063] The connection pad has a connection pad 151 and a connection pad 152 at different positions. The electrode pad 113 has an electrode pad 1131 and an electrode pad 1132 at different positions. The bonding wire 180 has a bonding wire 181 that connects the connection pad 151 and the electrode pad 1131, and a bonding wire 182 that connects the connection pad 152 and the electrode pad 1132. A first reference line S1 that passes through a predetermined first position of the connection pad 151, for example, the connection point C1, and a predetermined second position of the connection pad 152, for example, the connection point C2, is parallel to the scanning direction. By arranging the connection pads 151 and 152 in parallel with the scanning direction in this way, the connection pads 151 and 152 are easily and safely prevented from being affected by the adjustment process of the resonator 153 by the ion gun.

[0064] Furthermore, a second reference line S2 passing through a predetermined third position of the electrode pad 1131, for example, the connection point C3, and a predetermined fourth position of the electrode pad 1132, for example, the connection point C4, is parallel to the scanning direction. In this way, by positioning the electrode pads 1131 and 1132 side by side parallel to the scanning direction, the adjustment process of the resonance unit 153 by the ion gun is easily and safely prevented from affecting the connection pads 151 and 152. Furthermore, by arranging the connection pads 151 and 152 side by side parallel to the scanning line, their positional relationship is simplified, and bonding of the bonding wires 181 and 182 is also easy and efficient.

[0065] Furthermore, the center of the resonating unit 153 of the MEMS element 150 is located on a line passing through the midpoint between the first and second positions and the midpoint between the third and fourth positions. In this way, the resonating unit 153, the connection pads 151 and 152, and the electrode pads 1131 and 1132 are positioned symmetrically in the y direction, allowing signals to be transmitted evenly between the electrode pads 1131 and 1132 and the resonating unit 153 with an efficient positional relationship. This also makes it easier to form the piezoelectric resonating device 1.

[0066] Furthermore, the distance between the first reference line S1 and the second reference line S2 is shorter than the distance between the second reference line S2 and the edge of the mounting surface 1110, i.e., the frame portion 1101, in the x-direction perpendicular to the second reference line S2. In this way, by making the distance between the connection pads 151, 152 and the electrode pads 1131, 1132 shorter than the range in which they can be positioned on the mounting surface 1110 and locating these pads close to each other, it is possible to connect the pads compactly without making the bonding wire 180 longer than necessary. This makes it possible to prevent damage to the bonding wire 180 and to suppress loss of signal strength due to the bonding wire 180.

[0067] Furthermore, the distance between connection points C1 and C3 of bonding wire 181 is equal to the distance between connection points C2 and C4 of bonding wire 182. In this way, by connecting bonding wires 181 and 182 at the same distance in the xy plane, the distances between bonding wires 181 and 182 can also be made approximately equal. This allows signal transmission by bonding wires 181 and 182 to be performed evenly.

[0068] Furthermore, the line connecting the first position and the third position, and the line connecting the second position and the fourth position are each perpendicular to the scanning direction. In this way, the bonding wires 181 and 182 extend in a straight direction away from the resonator unit 153 in a plan view, so that the pads can be efficiently connected with short bonding wires 181 and 182.

[0069] The scanning direction is a direction along the longitudinal direction of the resonating unit 153 or a direction perpendicular to the longitudinal direction. In this way, by performing the adjustment operation while scanning in a direction along the sides of the rectangle, the adjustment operation time between each scan can be made equal, and uniform adjustment can be easily performed in a single process. Also, the number of scans does not need to be increased more than necessary.

[0070] The mounting surface 1110 has a protrusion 1111. The electrode pads 1131 and 1132 are located on the protrusion 1111. The surfaces of the electrode pads 1131 and 1132 and the surfaces of the connection pads 151 and 152 are located at the same distance from the mounting surface 1110. By aligning the heights of the electrode pads 1131, 1132 and the connection pads 151, 152 in this way, it becomes easier to connect the bonding wires 181, 182, and it is also possible to prevent the bonding wires 181, 182 from drooping too much and hitting the corners of the MEMS element 150 or the like and causing damage.

[0071] Furthermore, in plan view, between the electrode pads 1131, 1132 and the connection pads 151, 152, a resin member 185 is positioned at least partially between the bonding wires 181, 182 and the mounting surface 1110. Even if the bonding wires 181, 182 droop, they are in contact with and supported by this resin member 185, which prevents them from coming into contact with the MEMS element 150, particularly the corners, and therefore the bonding wires 181, 182 are less likely to be damaged.

[0072] Furthermore, at positions where resin members 185, 185a, and 185b overlap bonding wires 181 and 182 in a plan view, the maximum distance from each of them to mounting surface 1110 is equal to or greater than the distance between mounting surface 1110 and upper surfaces 1500 of connection pads 151 and 152. In other words, bonding wires 181 and 182 are more likely to come into contact with resin members 185, 185a, and 185b before hitting corners of MEMS element 150, and are supported by resin members 185, 185a, and 185b, etc., effectively preventing the bonding wires from hitting corners of MEMS element 150 and damaging them.

[0073] Furthermore, the resin members 185, 185a, and 185b cover the corners of the MEMS element 150, i.e., the edges of the upper surface 1500, at least between the electrode pads 1131 and 1132 and the connection pads 151 and 152. This sufficiently reduces the possibility that the bonding wires 181 and 182 will come into direct contact with the corners of the MEMS element 150, and therefore, the possibility that the bonding wires 181 and 182 will be damaged can be sufficiently reduced.

[0074] Furthermore, at least a portion of bonding wire 180 is located inside resin member 185a between electrode pad 113 and connection pads 151 and 152. In this way, by at least a portion of bonding wire 180 being covered by resin member 185a, unnecessary movement of bonding wire 180 is suppressed, and problems such as damage to the bonding wire are reduced.

[0075] Furthermore, the upper surface 1500 of the MEMS element 150 has a space 155 with a predetermined area or more corresponding to the size of the suction port of the suction device, at a position that does not overlap the connection pads 151, 152, the resonating unit 153, and the bonding wires 181, 182 in a plan view. This makes it possible to easily obtain appropriate mounting accuracy when mounting the MEMS element 150 to the base 100, while avoiding damage to the resonating unit 153 and the like and excessive loads due to suction.

[0076] Furthermore, the space 155 is located on the upper surface 1500 on the opposite side of the connection pads 151 and 152 with respect to the resonating unit 153. In this way, the MEMS element 150 is attracted at a position far from not only the resonating unit 153 but also the connection pads 151 and 152 and is then transported to the attachment position on the base 100, which can sufficiently reduce problems with the MEMS element 150 during its movement to the attachment position.

[0077] Furthermore, the MEMS element 150 is bonded to the mounting surface 1110 via an adhesive member 170. The adhesive member 170 extends outward beyond at least the corners of the MEMS element 150 in a plan view. In this way, the adhesive member 170 stably fixes at least the four corners of the MEMS element 150, thereby effectively preventing the MEMS element 150, and in particular the resonating unit 153, from being damaged by pressure when the MEMS element 150 is attached or when the bonding wire 180 is ultrasonically bonded.

[0078] The MEMS element 150 includes a semiconductor substrate including a handling layer 1501 and an insulating layer 1502, a doped layer 1503 serving as a lower electrode, a piezoelectric layer 1504, and an upper electrode 1505 stacked in this order from the mounting surface 1110 upward, i.e., from the side closest to the mounting surface 1110. The adhesive member 170 has an upper end positioned lower than the upper end of the semiconductor substrate. That is, fillet portions 1701 and 1702 formed by the adhesive member 170 protruding from the lower surface of the MEMS element 150 do not need to contact the conductor portion of the MEMS element 150 located above the laminated structure and the piezoelectric layer 1504. This allows the MEMS element 150 to be bonded to the mounting surface 1110 within a range that is unlikely to cause problems such as short circuits, and also prevents further deviations in frequency characteristics such as the resonant frequency and changes in the conductivity of conductor portions such as the doped layer 1503.

[0079] Furthermore, at least the surfaces of the electrode pads 1131, 1132 and the connection pads 151, 152 are made of gold, which suppresses corrosion reactions and reduces resistance loss, etc., allowing proper signal transmission.

[0080] The above embodiment is merely an example, and various modifications are possible. For example, in the above embodiment, the case where the lid 120 seals the housing 111 and the MEMS element 150 is used as an oscillator has been described. However, the external connection pads may be connected to a predetermined detection circuit and used as a detection unit that detects acceleration, etc. Furthermore, the MEMS element 150 may be configured as a detection unit in which a substance or the like can contact or deposit on the resonating unit 153 of the MEMS element 150 directly or via a predetermined coating, etc., and the detection unit may be capable of detecting the contact frequency or the deposited weight, etc., using a detection circuit, etc. For example, when the MEMS element 150 is used as a gas sensor, the resonant frequency of the MEMS element 150 is measured before being placed in the measurement area. This is the resonant frequency in the absence of the target gas, i.e., the reference frequency. The MEMS element 150 is then placed in the measurement area, the resonant frequency of the MEMS element 150 is measured, and the presence or absence of the target gas can be determined by comparing this resonant frequency with the reference frequency.

[0081] Furthermore, in the above embodiment, the connection pads 151, 152 of the MEMS element 150 and the electrode pads 1131, 1132 are connected by bonding wires, but this is not limiting and any conductive wiring member may be used.

[0082] In the above embodiment, the electrode pads 1131 and 1132 and the connection pads 151 and 152 are described as being rectangular in shape and of the same size and orientation in a plan view. However, they may not be rectangular, and they may not be oriented in the same direction or of the same size. If they are not rectangular in a plan view, they may be circular, or may have some or all of the corners of a rectangle removed or rounded. Even if the sizes and / or shapes are different, the connection points C1 and C2 and the connection points C3 and C4 may be located at the same positions in the x direction. Furthermore, the electrode pads 1131 and 1132 may be arranged so that the x coordinates of their centers of gravity are equal. Furthermore, the connection pads 151 and 152 may be arranged so that the x coordinates of their centers of gravity are equal.

[0083] Furthermore, here, the predetermined positions of the connection pads 151, 152 and the electrode pads 1131, 1132 are defined as the first to fourth positions, respectively, at the connection points C1 to C4 with each bonding wire 180, but the predetermined positions may also be the center of gravity or central position of each pad, as long as the setting method is consistent.

[0084] Furthermore, at least one of the first reference line S1 and the second reference line S2 does not have to be parallel to the scanning direction. If it is difficult to position the lines symmetrically with respect to the center line Sy due to the shape of the resonator unit 153, the lines may be adjusted as appropriate. Furthermore, depending on the positional relationship, the lengths or distances in the x-direction of the bonding wires 181 and 182 do not have to be equal to each other, and the bonding wires 181 and 182 do not have to extend along the x-direction in a plan view.

[0085] Furthermore, a protective layer may be provided on the upper surface of the upper electrode 1505. This can prevent oxidation or scraping of the upper electrode 1505. The protective layer may be made of, for example, AlN.

[0086] The top surface of the upper electrode 1505 may be made of gold (Au).

[0087] In addition, the specific configurations, contents and procedures of the processing operations, etc. shown in the above embodiments can be modified as appropriate without departing from the spirit of the present disclosure. The scope of the present invention includes the scope of the invention described in the claims and its equivalents. [Industrial Applicability]

[0088] The present disclosure can be used in piezoelectric resonator devices. [Explanation of symbols]

[0089] 1. Piezoelectric resonant device 100 base 110, 110a substrate 1101 Frame 1102 Base 111 Storage unit 1110 Placement surface 1111 Protrusion 113, 1131, 1132 electrode pads 112 Frame-shaped metallized layer 113, 1131, 1132 electrode pads 114, 1141~1144 external connection pads 115 through hole 1161, 1162 through conductor 120, 120a lid body 121 Storage unit 150, 150a MEMS element 1500 Top 1501 Handling Layer 1502 Insulation layer 1503 doped layer 1504 Piezoelectric layer 1505 Upper electrode 151, 152 connection pads 153 Resonance section 1531 Resonance means 154 Wiring 155 spaces 170, 171a to 171d adhesive members 180, 181, 182 Bonding wire 185, 185a, 185b Resin members C1~C4 connection points S1 1st reference line S2 2nd reference line Ss scanning direction Sy center line

Claims

1. a substrate having a first surface; a first connecting conductor located on the first surface; a MEMS element located on the first surface, the MEMS element having a second surface, a second connecting conductor located on the second surface, and a resonator portion exposed on the second surface and electrically connected to the second connecting conductor; a wiring conductor that electrically connects the first connecting conductor and the second connecting conductor; Equipped with the first connecting conductor, the second connecting conductor, and the wiring conductor are located outside a range obtained by extending the range of the resonator in a predetermined direction in a plan view of the first surface from above; Piezoelectric resonant device.

2. the second connecting conductor is located between the first connecting conductor and the resonator unit.

2. The piezoelectric resonator device of claim 1.

3. the second connection conductor has a first connection portion and a second connection portion at different positions; the first connecting conductor has a third connecting portion and a fourth connecting portion at different positions; the wiring conductor includes a first wiring conductor connecting the first connection portion and the third connection portion, and a second wiring conductor connecting the second connection portion and the fourth connection portion; a first reference line passing through a predetermined first position of the first connection portion and a predetermined second position of the second connection portion is parallel to the predetermined direction; 3. The piezoelectric resonant device according to claim 1.

4. The piezoelectric resonant device according to claim 3 , wherein a second reference line passing through a third predetermined position of the third connection portion and a fourth predetermined position of the fourth connection portion is parallel to the predetermined direction.

5. The piezoelectric resonant device according to claim 4 , wherein the center of the resonant portion of the MEMS element is located on a line passing through a midpoint between the first position and the second position and a midpoint between the third position and the fourth position.

6. The piezoelectric resonant device according to claim 5 , wherein the distance between the first reference line and the second reference line is smaller than the distance between the second reference line and an edge of the first surface in a direction perpendicular to the second reference line.

7. A piezoelectric resonant device as described in any one of claims 3 to 6, wherein the distance between each connection position of the first wiring conductor with the first connection portion and the third connection portion is equal to the distance between each connection position of the second wiring conductor with the second connection portion and the fourth connection portion.

8. A piezoelectric resonant device as described in any one of claims 3 to 7, wherein a line connecting the first position and a predetermined third position of the third connection part, and a line connecting the second position and a predetermined fourth position of the fourth connection part are each perpendicular to the predetermined direction.

9. 9. The piezoelectric resonant device according to claim 1, wherein the predetermined direction is a direction along a longitudinal direction of the resonant portion or a direction perpendicular to the longitudinal direction.

10. the first surface has a protrusion; the first connecting conductor is located on the protrusion; a surface of the first connecting conductor and a surface of the second connecting conductor are positioned at the same distance from the first surface; The piezoelectric resonant device according to any one of claims 1 to 9.

11. a resin member is located between the first connection conductor and the second connection conductor in the plan view, at least partially between the wiring conductor and the first surface; The piezoelectric resonant device according to any one of claims 1 to 10.

12. The piezoelectric resonant device of claim 11, wherein the resin member has a maximum distance from the first surface at a position where it overlaps with the wiring conductor in the planar view that is equal to or greater than the distance between the first surface and the surface of the second connecting conductor.

13. 13. The piezoelectric resonator device according to claim 11, wherein the resin member covers an edge of the MEMS element at least between the first connecting conductor and the second connecting conductor.

14. 14. The piezoelectric resonant device according to claim 11, wherein the wiring conductor is located inside the resin member at least in a portion between the first connecting conductor and the second connecting conductor.

15. A piezoelectric resonant device as described in any one of claims 1 to 14, wherein the second surface of the MEMS element has a space of a predetermined area or more in a position that does not overlap with the second connecting conductor, the resonant portion, and the wiring conductor in a planar view.

16. The piezoelectric resonator device according to claim 15 , wherein the space is located on the second surface on an opposite side of the resonator portion from the second connecting conductor.

17. the MEMS element is bonded to the first surface via an adhesive member; the adhesive member extends outward from at least a corner of the MEMS element in a plan view; The piezoelectric resonant device according to any one of claims 1 to 16.

18. the MEMS element includes a semiconductor substrate, a lower electrode, a piezoelectric material, and an upper electrode stacked in this order from the first surface upward; The piezoelectric resonant device according to claim 17 , wherein the adhesive member has an upper end positioned at a side surface of the MEMS element lower than an upper end position of the semiconductor substrate.

19. 19. The piezoelectric resonator device according to claim 1, wherein at least the surfaces of the first connecting conductor and the second connecting conductor are made of gold.

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