Piezoelectric resonator and packaged device

Abstract

The embodiment of the present application provides a piezoelectric resonator and a packaged device, wherein the piezoelectric resonator comprises a device layer, a piezoelectric layer and an electrode layer; the device layer comprises a vibrator structure and an anchor point structure; the vibrator structure is fixedly connected with the anchor point structure; the piezoelectric layer is located on the vibrator structure and comprises a first piezoelectric region and a second piezoelectric region which are isolated from each other; the vibrator structure serves as a bottom electrode of the piezoelectric layer and is grounded; the electrode layer is located on the upper surface of the piezoelectric layer and comprises a driving electrode and a sensing electrode which are isolated from each other; the driving electrode is located on the upper surface of the first piezoelectric region, and the sensing electrode is located on the upper surface of the second piezoelectric region. In addition, the piezoelectric resonator is packaged in a wafer level, and the device layer, the substrate and the packaging cover plate are grounded through electrical connection, so that the feed-through capacitance between the driving electrode and the sensing electrode can be reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a piezoelectric resonator and its packaging device. Background Technology

[0002] In piezoelectric resonators, feedthrough capacitance is one of the key factors affecting device performance. Feedthrough capacitance refers to the capacitance formed by direct coupling from the input port to the output port through a parasitic path without energy conversion via the resonant structure. Large feedthrough capacitance leads to increased signal crosstalk, decreased out-of-band rejection ratio, and in severe cases, even masking the resonator's intrinsic response, thus degrading the overall device performance. In wafer-level packaged piezoelectric resonators, feedthrough capacitance is generated between the input and output through the substrate and the package cover. Especially in high-frequency applications, feedthrough capacitance can significantly impact device performance. Summary of the Invention

[0003] To address the existing technical problems, this application provides a piezoelectric resonator and its packaged device that can effectively reduce feedthrough capacitance.

[0004] In a first aspect, a piezoelectric resonator is provided, comprising: a device layer, a piezoelectric layer, and an electrode layer; the device layer includes an oscillator structure and an anchor structure; the oscillator structure and the anchor structure are fixedly connected; the piezoelectric layer is located on the oscillator structure and includes a first piezoelectric region and a second piezoelectric region that are isolated from each other; the oscillator structure serves as the bottom electrode of the piezoelectric layer and is grounded; the electrode layer is located on the upper surface of the piezoelectric layer and includes a driving electrode and a sensing electrode that are isolated from each other; the driving electrode is located on the upper surface of the first piezoelectric region, and the sensing electrode is located on the upper surface of the second piezoelectric region.

[0005] In a second aspect, a packaging device is provided, including a packaging cover, a substrate, and a piezoelectric resonator as described in any embodiment of this application; wherein the packaging cover is disposed on the driving electrode and the sensing electrode; the device layer is fixed on the substrate; the packaging cover is electrically connected to the substrate and the device layer through at least one through hole, and is used to ground together with the substrate and the device layer.

[0006] The piezoelectric resonator provided in the above embodiment sets the piezoelectric layer as a first piezoelectric region and a second piezoelectric region that are isolated from each other; the driving electrode is located on the first piezoelectric region, and the sensing electrode is located on the second piezoelectric region; the driving electrode and the sensing electrode are isolated from each other; the oscillator structure serves as the bottom electrode of the piezoelectric layer and is grounded. Thus, by covering the piezoelectric layer with an electrode layer, and since the driving electrode and the sensing electrode are located on the same plane, and the electrode layer has a relatively small thickness, the feedthrough capacitance formed between the driving electrode and the sensing electrode can be reduced.

[0007] The packaged device provided in the above embodiments belongs to the same technical concept as the piezoelectric resonator embodiments, and thus has the same technical effect as the piezoelectric resonator embodiments, which will not be repeated here. Attached Figure Description

[0008] Figure 1A This is a schematic diagram of the structure of a piezoelectric resonator in related technologies; Figure 1B This is a schematic diagram of the equivalent circuit of a piezoelectric resonator in related technologies; Figure 2 This is a schematic diagram of the structure of a piezoelectric resonator in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of a piezoelectric resonator in another embodiment of this application; Figure 4 This is a schematic diagram of the hollowed-out area in one embodiment of this application; Figure 5A This is a schematic diagram of the equivalent circuit of a piezoelectric resonator in one embodiment of this application; Figure 5B This is a schematic diagram of the width extension mode in one embodiment of this application; Figure 6 This is a top view of a piezoelectric resonator in another embodiment of this application; Figure 7 This is a top view of a piezoelectric resonator in another embodiment of this application; Figure 8 This is a cross-sectional schematic diagram of the packaged device along the thickness direction in one embodiment of this application; Figure 9A This is an equivalent circuit diagram of an embodiment of the present application when the package cover and the substrate are not grounded; Figure 9B This is an equivalent circuit diagram of the package cover, device layer and substrate sharing a common ground in one embodiment of this application.

[0009] Explanation of reference numerals in the attached figures 01. Upper electrode; 02. Lower electrode; 1. Oscillator structure; 11. First oscillator; 12. Second oscillator; 13. Second connecting beam; 2. Piezoelectric layer; 21. First piezoelectric region; 22. Second piezoelectric region; 3. Electrode layer; 31. Driving electrode; 32. Sensing electrode; 4. Device layer; 5. Anchor point structure; 6. First connecting beam; 7. Hollow area; 81. Encapsulation cover plate; 82. Through hole; 821. First through hole; 822. Second through hole; 823. Third through hole; 83. Substrate; 84. First insulating layer; 85. Second insulating layer; 86. Third insulating layer; 87. Fourth insulating layer; 88. Fifth insulating layer; 9. RDL; 91. Input terminal; 92. Output terminal; 93. Ground terminal. Detailed Implementation

[0010] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0012] In the following description, the phrase "some embodiments" refers to a subset of all possible embodiments. It should be noted that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0013] In the following description, the terms "first," "second," and "third" are used merely to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that "first," "second," and "third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0014] The inventors of this application have conducted the following analysis in their research on piezoelectric resonators: like Figure 1A The diagram shows a schematic of a traditional piezoelectric resonator. A lower electrode 02 is fabricated on the oscillator structure of the device layer. A piezoelectric layer 2 is located between the upper electrode 01 and the lower electrode 02, forming a stacked structure. The lower electrode 01 and the upper electrode 02 are used to connect the driving signal and the sensing signal, respectively. The piezoelectric layer 2, acting as a dielectric, has a certain dielectric constant and forms a parallel-plate capacitor C0 between the upper electrode 01 and the lower electrode 02. When an AC signal is applied to the upper electrode 01, part of the signal is directly coupled to the lower electrode 02 through C0 without undergoing a mechanical-to-electrical signal conversion, thus forming a feedthrough capacitor. The equivalent circuit of this resonator structure is shown below. Figure 1B As shown, C0 is the feedthrough capacitance between the upper and lower electrodes, Rm is the equivalent resistance formed in the device layer where the oscillator structure 1 is located, L is the equivalent inductance formed in the device layer where the oscillator structure 1 is located, and Cm is the equivalent capacitance formed in the device layer where the oscillator structure 1 is located.

[0015] Therefore, the inventors proposed setting an electrode layer 3 above the piezoelectric layer 2, forming driving electrodes 31 and sensing electrodes 32 arranged at intervals, and grounding the device layer below the piezoelectric layer 2 to reduce the feedthrough capacitance and improve the resonator performance.

[0016] like Figure 2As shown in the figure, this application provides a piezoelectric resonator, including: a device layer, a piezoelectric layer 2, and an electrode layer 3. The device layer may include an oscillator structure 1 and an anchor structure 5. The electrode layer 3 may include a driving electrode 31 and a sensing electrode 32. The oscillator structure 1 is fixedly connected to the anchor structure 5 and fixed on the substrate through the anchor structure 5. The piezoelectric layer 2 is located on the oscillator structure 1, and the driving electrode 31 and the sensing electrode 32 are located on the piezoelectric layer 2.

[0017] The piezoelectric layer 2 includes a first piezoelectric region 21 and a second piezoelectric region 22 that are isolated from each other; the driving electrode 31 is located on the first piezoelectric region 21, for example, on the upper surface of the first piezoelectric region 21, and the sensing electrode 32 is located on the second piezoelectric region 22, for example, on the upper surface of the second piezoelectric region 22; the driving electrode 31 and the sensing electrode 32 are isolated from each other.

[0018] In one embodiment, the device layer is made of heavily doped single-crystal silicon, and the doping concentration is not less than 10^19 atoms / cm^3.

[0019] In one embodiment, the driving electrode 31 serves as the input terminal, the oscillator structure 1 serves as the bottom electrode of the piezoelectric layer 2 and is grounded, converting external electrical signals into mechanical motion through the piezoelectric layer 2. For example, the external electrical signal can be an AC signal. The sensing electrode 32 serves as the output terminal, using the piezoelectric layer 2 to convert the mechanical motion into an electrical signal for output.

[0020] For example, the driving electrode 31 receives an external electrical signal and outputs an electric field to the first piezoelectric region 21 based on the external electrical signal, thereby driving the oscillator structure 1 to resonate. The resonance of the oscillator structure 1 causes the second piezoelectric region 22 to generate induced charges, which are then output through the sensing electrode 32.

[0021] In one embodiment, the edges of the piezoelectric layer 2 and the electrode layer 3 are aligned and aligned with the edges of the oscillator structure 1. For example, in a top view, the edges of the oscillator structure 1 are rectangular, and the anchor points 5 are located on both sides of the oscillator structure 1, for example, connected to two opposite sides of the edge of the oscillator structure 1.

[0022] In one embodiment, the first piezoelectric region 21 and the second piezoelectric region 22 can be two regions of equal area and arranged at intervals. For example, the minimum distance between the edges of the first piezoelectric region 21 and the second piezoelectric region 22 is greater than 0.

[0023] In one embodiment, the piezoelectric layer 2 can be made of aluminum nitride, lead zirconate titanate (PZT), or other materials. The electrode layer 3 can be made of metal, or highly doped single-crystal silicon or polycrystalline silicon, with a doping concentration of not less than 10^19 atoms / cm^3.

[0024] In one embodiment, the oscillator structure 1 can be used for grounding. The material of the oscillator structure 1 can be heavily doped monocrystalline silicon with a doping concentration of not less than 10^19 atoms / cm^3. Since the mechanical damping of silicon is generally smaller than that of metal materials, using heavily doped monocrystalline silicon instead of traditional metal as the conductive layer can reduce mechanical losses and improve the quality factor (Q value). The oscillator structure 1 can operate in the width extension mode.

[0025] In one embodiment, the area of ​​the piezoelectric layer 2 may be smaller than the area of ​​the oscillator structure 1 in a top view. For example, the projection area of ​​the edge of the piezoelectric layer 2 onto the oscillator structure 1 may fall within the edge of the oscillator structure 1. Exemplarily, the edge of the piezoelectric layer 2 may be obtained by proportionally reducing the edge of the oscillator structure 1.

[0026] In one embodiment, the driving electrode 31 and the sensing electrode 32 are coplanar, that is, the driving electrode 31 and the sensing electrode 32 are on the same plane, for example, on the same plane perpendicular to the stacking direction.

[0027] In one embodiment, the edge of the driving electrode 31 may be aligned with the edge of the first piezoelectric region 21, or the projection area of ​​the edge of the driving electrode 31 onto the first piezoelectric region 21 may fall within the edge of the first piezoelectric region 21. For example, the edge of the driving electrode 31 may be obtained by proportionally reducing the edge of the first piezoelectric region 21.

[0028] In one embodiment, the edge of the sensing electrode 32 may be aligned with the edge of the second piezoelectric region 22, or the projection area of ​​the edge of the sensing electrode 32 onto the second piezoelectric region 22 may fall within the edge of the second piezoelectric region 22. For example, the edge of the sensing electrode 32 may be obtained by proportionally reducing the edge of the second piezoelectric region 22.

[0029] Thus, by covering the piezoelectric layer 2 with the electrode layer 3, the feedthrough capacitance formed between the driving electrode 31 and the sensing electrode 32 can be reduced because the driving electrode 31 and the sensing electrode 32 are located on the same plane and the electrode layer 3 has a relatively small thickness.

[0030] In some embodiments, such as Figure 3As shown, it also includes: a first connecting beam 6; the vibrator structure 1 is fixedly connected to the anchor point structure 5 through the first connecting beam 6; the anchor point structure 5 is located on both sides of the vibrator structure 1, and the vibrator structure 1 is fixedly connected to the anchor point structure 5 on different sides through the first connecting beam 6 respectively.

[0031] In some embodiments, the first connecting beams 6 located on both sides of the oscillator structure 1 are symmetrically distributed based on the oscillator structure 1.

[0032] In one embodiment, the oscillator structure 1 is symmetrically distributed, that is, symmetrically distributed based on the central axis of the oscillator structure 1. Here, the central axis refers to the central axis along the direction perpendicular to the first direction.

[0033] In this way, the two connecting beams are symmetrically distributed, and the connection support can be achieved by matching the symmetry of the vibration modes. At the same time, the parasitic modes, stress imbalance and process errors caused by asymmetry are eliminated, and finally the resonator performance of low loss, high Q value and high consistency is achieved.

[0034] In some embodiments, such as Figure 3 As shown, the first connecting beam 6 includes at least one hollow area 7.

[0035] In one embodiment, the hollow region 7 can penetrate the first connecting beam 6 along the stacking direction of the piezoelectric layer 2 and the oscillator structure 1. For example, in a top view, the hollow region 7 can be located at the center of the first connecting beam 6. The stacking direction, which is also the thickness direction, can be represented by the Z direction in the figure.

[0036] In this embodiment, the top view is the cross-section along the plane of the piezoelectric layer 2, and the cross-section is perpendicular to the stacking direction.

[0037] For example, on a top view, the geometric center of the hollowed-out area 7 can coincide with the geometric center of the first connecting beam 6.

[0038] In one embodiment, the first connecting beam 6 may include a first segment and a second segment. The length of the first segment in the direction perpendicular to the first direction may be greater than or equal to the length of the oscillator structure 1. The hollowed-out area 7 is located on the first segment, and the first segment is connected to the oscillator structure 1. The second segment may be the part connecting the first segment and the anchor point structure 5, and the length of the second segment may be less than the length of the first segment.

[0039] Thus, the abrupt change in the transmission path is formed by the hollow area 7 in the first connecting beam. As a result, in the path of mechanical wave transmission from the oscillator structure 1 through the first connecting beam 6 to the anchor structure 5, the impedance discontinuity in the mechanical wave propagation path can be caused by this abrupt structure. Part of the energy is reflected back to the resonant region, reducing the energy leakage from the anchor structure 5 and further improving the Q value.

[0040] In some embodiments, such as Figure 4 As shown, on the top view, the first distance L1 between the first edge of the hollow area 7 and the first edge of the first connecting beam 6 is less than the second distance L2 between the second edge of the hollow area 7 and the second edge of the first connecting beam 6; wherein, the first edge is perpendicular to the first direction, and the second edge is perpendicular to the first edge.

[0041] In one embodiment, the first edge of the first connecting beam 6 is connected to the oscillator structure 1 or the anchor structure 5, and the second edge is an edge in another direction perpendicular to the first edge. For example, the first edge is the edge perpendicular to the first direction, and the second edge is the edge parallel to the first direction.

[0042] Thus, by making the dimensions of the first connecting beam 6, which is hollowed out, different in different directions, impedance discontinuity is further formed on the mechanical wave propagation path, thereby reducing energy leakage of the anchor structure 5.

[0043] like Figure 5A The diagram shown is an equivalent circuit diagram using the resonator structure described above. The oscillator structure 1 is grounded. This refers to the feedthrough capacitance between the driving electrode 31 and the sensing electrode 32. The driving electrode 31 and the sensing electrode 32 are typically very thin, resulting in a small cross-sectional area along their thickness direction, thus forming a small capacitance. Much smaller than C0. Therefore, this method can avoid the adverse effects of the feedthrough capacitance generated at the input and output terminals through piezoelectric layer 2 on device performance. A schematic diagram of the in-plane displacement field of the oscillator operating in the width-extended mode can be shown as follows: Figure 5B As shown.

[0044] Thus, by forming beams with different cross-sectional areas on the first connecting beam 6, the energy leaking to the anchor structure 5 through the first connecting beam 6 is reduced when the oscillator structure 1 vibrates.

[0045] In some embodiments, the structure further includes: a first connecting beam 6; the oscillator structure 1 includes: a first oscillator 11, a second oscillator 12, and a second connecting beam 13 connecting the first oscillator 11 and the second oscillator 12 along a first direction.

[0046] The anchor point structure 5 is located on both sides of the second connecting beam 13 along the second direction, and is fixedly connected to the second connecting beam 6 through the first connecting beam 13, respectively. The second direction is perpendicular to the first direction.

[0047] In one embodiment, on the top view, the top view direction is the stacking direction, the first oscillator 11, the second connecting beam 13 and the second oscillator 12 are arranged sequentially along the first direction, which is the X direction, and the second direction perpendicular to the first direction on the top view is the Y direction.

[0048] In one embodiment, the first oscillator 11 and the second oscillator 12 are two oscillators of the same size, which can also be referred to as mass blocks. The first oscillator 11 and the second oscillator 12 are symmetrically distributed based on the second connecting beam 13. For example, they can be symmetrically distributed based on the central axis of the second connecting beam 13 in the second direction.

[0049] For example, in a top view, the first oscillator 11 and the second oscillator 12 can be rectangular, square, circular, or any regular or irregular shape. The width of the second connecting beam 13 in the second direction can be less than the width of the first oscillator 11 and / or the second oscillator 12 in the second direction.

[0050] In one embodiment, in the second direction, there is a pair of first connecting beams 6 and anchor point structures 5 on each side of the second connecting beam 13, and the anchor point structures 5 on each side are connected to the second connecting beam 13 through the first connecting beams 6. For example, the first connecting beams 6 located on both sides of the second connecting beam 13 can be symmetrically distributed based on the second connecting beam 13, and the anchor point structures 5 located on both sides of the second connecting beam 13 can also be symmetrically distributed based on the second connecting beam 13.

[0051] For example, in a top view, the length of the second connecting beam 13 in the first direction can be greater than the length of the first connecting beam 6 in the first direction.

[0052] In one embodiment, the first connecting beams 6 on both sides of the second connecting beam 13 can be symmetrically distributed based on the second connecting beam 13, and the anchor point structures 5 on both sides of the second connecting beam 13 can also be symmetrically distributed based on the second connecting beam 13.

[0053] In one embodiment, the first connecting beam 6 can be symmetrical about the central axis of the second connecting beam 13 in the second direction, and the anchor point structure 5 can also be symmetrical about the central axis of the second connecting beam 13 in the second direction.

[0054] In one embodiment, the first oscillator 11 and the second oscillator 12 can operate in the same-direction width-extension mode, or in other same-direction modes. Thus, by using the same-direction operating mode, the energy leakage from the anchor point can be reduced. In some embodiments, such as Figure 6 As shown, the first oscillator 11 and the second oscillator 12 are respectively provided with a first piezoelectric region 21 and a second piezoelectric region 22 arranged along the second direction; The driving electrode 31 is located on the first piezoelectric region 21 on the first oscillator 11 and the second oscillator 12; the sensing electrode 32 is located on the second piezoelectric region 22 on the first oscillator 11 and the second oscillator 12.

[0055] The first direction is the X direction, and the second direction is the Y direction.

[0056] In one embodiment, the piezoelectric layer 2 on each oscillator is divided into a first piezoelectric region 21 and a second piezoelectric region 22 that are isolated from each other along the second direction, and the electrode layer 3 on each oscillator is also divided into a driving electrode 31 and a sensing electrode 32 that are isolated from each other along the second direction.

[0057] In one embodiment, on each oscillator (first oscillator 11, second oscillator 12), the areas of the first piezoelectric region 21 and the second piezoelectric region 22 can be equal, and the areas of the driving electrode 31 and the sensing electrode 32 can also be equal.

[0058] In some embodiments, such as Figure 7 As shown, the first oscillator 11 is provided with the first piezoelectric region 21, and the second oscillator 12 is provided with the second piezoelectric region 22; The driving electrode 31 is located on the first piezoelectric region 21 on the first oscillator 11, and the sensing electrode 32 is located on the second piezoelectric region 22 on the second oscillator 12.

[0059] In one embodiment, the piezoelectric layer 2 on the first oscillator 11 serves as the first piezoelectric region 21, the piezoelectric layer 2 on the second oscillator 12 serves as the second piezoelectric region 22, the electrode layer 3 on the first oscillator 11 serves as the driving electrode 31, and the electrode layer 3 on the second oscillator 12 serves as the sensing electrode 32.

[0060] In another aspect, this application also provides a packaging device, including a packaging cover plate 81, a substrate 83, and a piezoelectric resonator as described in any of the foregoing embodiments of this application; at least one through-hole 82 is provided in the piezoelectric resonator and / or the packaging cover plate 81; the packaging cover plate 81 is electrically connected to the substrate 83 and the device layer 4 through at least one through-hole 82, and is used to ground together with the substrate 83 and the device layer 4. The through-hole 82 may include a first through-hole 821, a second through-hole 822, and a third through-hole 823.

[0061] The encapsulation cover plate 81 is disposed on the electrode layer 3; the device layer 4 is fixed on the substrate 83; the encapsulation cover plate 81 is electrically connected to the substrate 83 through at least one first through hole 821, and is used to ground together with the substrate 83. The first through hole 821 can penetrate the device layer 4, the piezoelectric layer 2 and the electrode layer 3 of the piezoelectric resonator.

[0062] In one embodiment, such as Figure 8 As shown, there can be multiple vias 82, and the packaged device may also include: a first insulating layer 84 located between the device layer 4 where the oscillator structure 1 is located and the substrate 83, and a second insulating layer 85 used to divide the electrode layer 3 and the piezoelectric layer 2 into an outer region and an inner functional region, wherein the inner functional region is used for electrical connection and to realize the piezoelectric function.

[0063] In one embodiment, the encapsulation cover 81 is used to form a sealed cavity. The encapsulation device may further include a third insulating layer 86 located between the encapsulation cover 81 and the second insulating layer 85. The via 82 may include a first via 821 connected between the first insulating layer 84, the device layer 4 containing the oscillator structure 1, and the electrode layer 3. The first via 821 is filled with the same material as the encapsulation cover 81 to achieve electrical connection between the substrate 83, the periphery of the device layer 4, and the encapsulation cover 81.

[0064] In one embodiment, the package cover 81 is further provided with a redistribution layer (RDL), the RDL 9 including an input terminal 91, an output terminal 92 and a ground terminal 93; the input terminal 91 is connected to the driving electrode 31 through the third through hole 823, the output terminal 92 is connected to the sensing electrode 32 through the third through hole 823, and the ground terminal 93 connects the substrate 83, the device layer 4 and the package cover 81 through the first through hole 821 and the second through hole 822.

[0065] In one embodiment, the via 82 may further include a second via 822 and a third via 823 connected between the RDL 9 and the electrode layer 3. The second via 822 and the third via 823 are filled with tungsten. The second via 822 is used to connect the peripheral area of ​​the device layer 4 to the RDL 9 and form a ground terminal 93. The third via 823 is used to connect the driving electrode 31 and the sensing electrode 32 to the RDL 9 and form an input terminal 91 and an output terminal 92.

[0066] In one embodiment, the packaged device may further include a fourth insulating layer 87 and a fifth insulating layer 88 located between RDL 9 and the package cover 81 for forming electrical isolation. The device layer 4 containing the oscillator structure 1 is grounded to the ground terminal 93 through the through-hole 82, converting the feedthrough capacitance formed between the input and output terminals into ground capacitances between the input and ground and between the output and ground, thereby improving device performance.

[0067] In one embodiment, the substrate 83 and device layer 4 are both heavily doped monocrystalline silicon, and the encapsulation cover plate 81 is heavily doped polycrystalline silicon, with a doping concentration of not less than 10^19 atoms / cm^3. The substrate 83, device layer 4, and encapsulation cover plate 81 are grounded through the polycrystalline silicon inside the first through-hole 821 and the tungsten inside the second through-hole 822, thereby reducing the feedthrough capacitance of the piezoelectric resonator and improving device performance.

[0068] For example, such as Figure 9A The diagram shows the equivalent circuit with the substrate and package cover ungrounded. When the substrate and package cover are at floating potentials, a loop is formed between the input and output terminals through the substrate and package cover, generating a feedthrough capacitance C0. This feedthrough capacitance C0 forms a parallel loop with the equivalent RCL circuit of the resonator, and C0 will affect the signal of the device. Figure 9B The equivalent circuit diagram shows the substrate, package cover, and device layer sharing a common ground. Since the substrate, package cover, and device layer form a common ground, a low-impedance loop is provided for high-frequency noise signals, reducing signal interference. A ground capacitance Cp is formed at both the output and input electrodes, effectively suppressing the feedthrough capacitance between the input and output electrodes. Sharing the device layer, package cover, and substrate as a common ground further reduces the feedthrough capacitance between the drive and sensing electrodes.

[0069] In another aspect, this application also provides an electronic device, including the piezoelectric resonator or packaged device described in any of the foregoing embodiments of this application.

[0070] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0071] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A piezoelectric resonator, characterized in that, include: Device layer, piezoelectric layer, electrode layer; The device layer includes an oscillator structure and an anchor point structure; The oscillator structure is fixedly connected to the anchor point structure; The piezoelectric layer is located on the oscillator structure and includes a first piezoelectric region and a second piezoelectric region that are isolated from each other. The oscillator structure serves as the bottom electrode of the piezoelectric layer and is grounded. The electrode layer is located on the upper surface of the piezoelectric layer and includes a driving electrode and a sensing electrode that are isolated from each other; the driving electrode is located on the upper surface of the first piezoelectric region and the sensing electrode is located on the upper surface of the second piezoelectric region.

2. The piezoelectric resonator according to claim 1, characterized in that, The driving electrode and the sensing electrode are arranged in the same plane; wherein the edge of the driving electrode is aligned with the edge of the first piezoelectric region, and / or the edge of the sensing electrode is aligned with the edge of the second piezoelectric region.

3. The piezoelectric resonator according to claim 1, characterized in that, Also includes: First connecting beam; The anchor point structure is located on both sides of the vibrator structure, and the vibrator structure is fixedly connected to the anchor point structure through the first connecting beam.

4. The piezoelectric resonator according to claim 3, characterized in that, The first connecting beams located on both sides of the oscillator structure are symmetrically distributed based on the oscillator structure.

5. The piezoelectric resonator according to claim 3, characterized in that, The first connecting beam contains at least one hollow area.

6. The piezoelectric resonator according to claim 5, characterized in that, In the cross-section of the first connecting beam, the first distance between the first edge of the hollowed-out area and the first edge of the first connecting beam is less than the second distance between the second edge of the hollowed-out area and the second edge of the first connecting beam; wherein the first edge is perpendicular to the first direction, and the second edge is perpendicular to the first edge.

7. The piezoelectric resonator according to claim 1, characterized in that, Also includes: First connecting beam; The oscillator structure includes: a first oscillator, a second oscillator, and a second connecting beam connecting the first oscillator and the second oscillator along a first direction; The anchor point structure is located on both sides of the second connecting beam along the second direction, and is fixedly connected to the second connecting beam through the first connecting beam, respectively, and the second direction is perpendicular to the first direction.

8. The piezoelectric resonator according to claim 7, characterized in that, The first oscillator and the second oscillator are respectively provided with a first piezoelectric region and a second piezoelectric region arranged along the second direction; The driving electrode is located on the first piezoelectric region on the first oscillator and the second oscillator; The sensing electrode is located on the second piezoelectric region on the first oscillator and the second oscillator.

9. The piezoelectric resonator according to claim 7, characterized in that, The first oscillator is provided with the first piezoelectric region, and the second oscillator is provided with the second piezoelectric region; The driving electrode is located on the first piezoelectric region on the first oscillator, and the sensing electrode is located on the second piezoelectric region on the second oscillator.

10. A packaged device, characterized in that, Includes a package cover, a substrate, and the piezoelectric resonator as described in any one of claims 1 to 9; The encapsulation cover is disposed on the driving electrode and the sensing electrode; the device layer is disposed on the substrate; the encapsulation cover is electrically connected to the substrate and the device layer through at least one through hole, and is used to ground together with the substrate and the device layer.

11. The packaged device according to claim 10, characterized in that, The encapsulation cover plate is also provided with a redistribution layer, which includes input terminals, output terminals, and a ground terminal; The input terminal is connected to the driving electrode through at least one through hole, the output terminal is connected to the sensing electrode through at least one through hole, and the ground terminal is grounded.

Images