Thin film piezoelectric acoustic resonator, method of manufacturing the same, and filter

Abstract

This invention provides a thin-film piezoelectric acoustic wave resonator, its manufacturing method, and a filter. The thin-film piezoelectric acoustic wave resonator includes: a first substrate; an upper electrode, a piezoelectric sheet, and a lower electrode stacked sequentially from top to bottom on the upper surface of the first substrate; the upper electrode, the piezoelectric sheet, and the lower electrode have overlapping regions in a direction perpendicular to the surface of the piezoelectric sheet; in the overlapping regions, a first gap is provided between the piezoelectric sheet and the upper electrode, and a second gap is provided between the piezoelectric sheet and the lower electrode; an isolation cavity surrounds the outer periphery of the piezoelectric sheet, and at least one connecting bridge is provided between the piezoelectric sheet and the substrate; the first gap and the second gap are connected through the isolation cavity.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device manufacturing, and in particular to a thin-film piezoelectric acoustic resonator, its manufacturing method, and a filter. Background Technology

[0002] Piezoelectric induction-based acoustic resonators are divided into surface acoustic wave (SAWR) resonators (SAWR) and bulk acoustic wave (BAWR) resonators. They are fundamental elements of radio frequency (RF) filters, which are core components of modern wireless communication RF front-ends and base station systems. Among them, bulk acoustic wave resonators have excellent characteristics such as low insertion loss and high quality factor, especially showing significant advantages over SAWR at frequencies above 2.0 GHz.

[0003] like Figure 1As shown, a traditional film bulk acoustic resonator (FBAR) consists of a thin-film piezoelectric sheet R40 mounted on a substrate R10, and upper electrode R30 and lower electrode R50 physically "welded" to its upper surface R41 and lower surface R42, respectively. The overlapping portion of the upper electrode R30 and lower electrode R50 rests on a cavity R20 on the substrate. Under the action of the alternating electric field generated by the upper and lower electrodes, bulk acoustic elastic vibrations are generated in the body and surface of the thin-film piezoelectric sheet R40 in the longitudinal direction (R1) and in the transverse direction (R2). Since the upper electrode R30 and lower electrode R50 are physically "welded" to the upper surface R41 and lower surface R42 of the thin-film piezoelectric sheet R40, these bulk acoustic elastic vibrations are naturally transmitted to the upper electrode R30 and lower electrode R50 and propagate outward along the upper electrode R30 and lower electrode R50. Therefore, a significant portion of the bulk acoustic wave (BAW) vibrations and their energy generated by the alternating electric fields produced by the upper electrode R30 and lower electrode R50 on the piezoelectric plate R40 are dissipated outside the piezoelectric plate and consumed. This is especially true when the thickness of the piezoelectric plate R40 is reduced (to achieve a higher longitudinal resonant frequency), and the areas of the piezoelectric plate R40, upper electrode R30, and lower electrode R50 are increased, leading to a greater proportion of consumed BAW energy and further negatively impacting the performance of the BAW resonator. However, in the basic device architecture of traditional and current BAW resonators, the loss of BAW vibration energy due to the dissipation of BAW energy from the piezoelectric plate R40 to the upper electrode R30 and lower electrode R50 is unavoidable. Furthermore, longitudinal acoustic wave oscillations are reflected at the interfaces R41 and R42 between the upper electrode R30 and the lower electrode R50 and the piezoelectric sheet R40, as well as at the interfaces R31 and R51 between the upper electrode R30 and the lower electrode R50 and the air. The resulting subharmonics also contribute to the noise. Moreover, due to the presence of the upper electrode R30 and the lower electrode R50, the piezoelectric induction resonant frequency depends not only on the thickness of the piezoelectric sheet and its longitudinal acoustic wave velocity, but also to some extent on the acoustic wave reflections from the upper and lower electrodes and their elastic stiffness. These negative impacts from the basic device structure become more severe as the required resonant frequency increases and the thickness of the piezoelectric sheet decreases further. Additionally, the direct contact between the two thin-film electrodes and the piezoelectric thin-film layer leads to residual stress and interface reflections of longitudinal and transverse acoustic waves at the interface due to the different physical properties of the materials, including variations caused by temperature changes. Furthermore, the propagation of acoustic waves from the piezoelectric thin-film layer into the thin-film electrodes results in energy loss.

[0004] The thickness of the piezoelectric sheet, electrodes, or dielectric layer, as well as the velocity of sound within them, in a piezoelectric acoustic wave resonator varies with temperature. Therefore, the resonant frequency of the piezoelectric acoustic wave resonator also changes with temperature. Most materials currently used in piezoelectric acoustic wave resonators exhibit a negative temperature coefficient of sound velocity (TCF), meaning the velocity of sound decreases with increasing temperature. For example, aluminum nitride has a TCF of -25 ppm / ℃, and molybdenum has a TCF of -60 ppm / ℃. Radio frequency (RF) filters constructed from piezoelectric acoustic wave resonators typically have a passband frequency response. The TCF of the piezoelectric acoustic wave resonator reduces the manufacturing yield of RF filters because devices or components constructed from piezoelectric acoustic wave resonators can only meet the passband bandwidth requirements within a certain temperature range. In most duplexer applications, a low TCF is important to meet requirements over a wide temperature range.

[0005] like Figure 2 As shown, the improved thin-film bulk acoustic resonator includes: a first electrode R120 located on a substrate R110, a piezoelectric layer R140 located above the first electrode R120, a second electrode R160 located above the piezoelectric layer R140, and an acoustic reflection structure R115 located below the first electrode R140; wherein, there is at least one gap R130 or R150 between the second electrode R160 and the first electrode R140, and this gap at least partially covers the effective region of the thin-film bulk acoustic resonator (the effective region is the region where the first electrode R1220, the second electrode R160 and the piezoelectric layer R140 overlap each other in the thickness direction), and its projection in the vertical direction is entirely within the acoustic reflection structure R115. This improved thin-film bulk acoustic resonator effectively eliminates the direct transmission of longitudinal acoustic waves generated by the piezoelectric layer R140 to the upper and lower electrodes (i.e., the first electrode R120 and the second electrode R160) in the longitudinal direction R101. However, in the horizontal direction R102, due to the physical effects of the piezoelectric material itself in the piezoelectric layer R140, the longitudinal bulk acoustic waves generated under the alternating electric field of the upper and lower electrodes will inevitably induce transverse bulk acoustic wave vibrations, which will propagate to the boundary of the effective region and form partial reflections. However, a considerable portion of the transverse acoustic waves will inevitably be consumed by the piezoelectric layer and the upper and lower electrodes outside the effective region. Furthermore, the structure disclosed in this improved resonator, which includes gaps (at least one gap R130 or R150) between the upper and lower electrodes and the piezoelectric layer, is formed by chemically releasing the sacrificial layer (such as silicon oxide) given that the height of this gap is between 1 nanometer and 500 nanometers. Typically, the size of the effective region is tens of micrometers or even larger, and effectively removing all sacrificial layer material through chemical release presents considerable technical difficulties.

[0006] Therefore, the main problems currently facing us are how to improve the physical differences between the piezoelectric film and the contact interface of the film electrode, reduce the acoustic energy loss in the piezoelectric film caused by the electrode, and how to provide a better method for forming bulk acoustic resonators. Summary of the Invention

[0007] This invention discloses a thin-film piezoelectric acoustic resonator, its manufacturing method, and a filter, which solves the problems of residual stress at the contact interface between the piezoelectric thin film and the electrode, and the leakage of acoustic waves from the electrode and the piezoelectric thin film in the prior art.

[0008] To solve the above-mentioned technical problems, the present invention provides a thin-film piezoelectric acoustic resonator, comprising:

[0009] First substrate;

[0010] The upper electrode, piezoelectric sheet, and lower electrode are disposed on the upper surface of the first substrate and stacked sequentially from top to bottom;

[0011] The upper electrode, piezoelectric sheet, and lower electrode have overlapping areas in a direction perpendicular to the surface of the piezoelectric sheet;

[0012] Within the overlapping area, a first gap is provided between the piezoelectric sheet and the upper electrode, and a second gap is provided between the piezoelectric sheet and the lower electrode;

[0013] An isolation cavity surrounds the outer periphery of the piezoelectric sheet body, and at least one connecting bridge is provided between the piezoelectric sheet body and the substrate;

[0014] The first gap and the second gap are connected through the isolation cavity.

[0015] The present invention also provides a filter comprising a plurality of the resonators described above.

[0016] The present invention also provides a method for manufacturing a thin-film piezoelectric acoustic resonator, comprising:

[0017] Provide a first substrate;

[0018] An upper electrode is formed on the first substrate;

[0019] A stacked structure is formed on the upper electrode, the stacked structure comprising: a piezoelectric sheet body, a first sacrificial layer located on the upper surface of the piezoelectric sheet body, a second sacrificial layer located on the lower surface of the piezoelectric sheet body, a third sacrificial layer located on the outer periphery of the piezoelectric sheet body, and at least one connecting bridge connecting the first substrate and the piezoelectric sheet body; the first sacrificial layer and the second sacrificial layer are connected together through the third sacrificial layer;

[0020] A lower electrode is formed on the stacked structure;

[0021] Remove the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer to form a first gap between the piezoelectric sheet body and the lower electrode, a second gap between the piezoelectric sheet body and the upper electrode, and an isolation cavity on the outer periphery of the piezoelectric sheet body;

[0022] The upper electrode, the piezoelectric sheet, and the lower electrode have overlapping regions in a direction perpendicular to the surface of the first substrate. The first gap and the second gap are at least partially located within the overlapping regions, and the overlapping regions are defined as the effective working area.

[0023] The beneficial effects of this invention are as follows:

[0024] In this invention, a tiny gap is formed between the piezoelectric sheet and the upper and lower electrodes within the effective operating region of the thin-film acoustic resonator. The electric field of the upper and lower electrodes can pass through the gap and be applied to the piezoelectric sheet. An isolation cavity is provided on the outer periphery of the piezoelectric sheet, and the piezoelectric sheet is connected to the first substrate via a connecting bridge for support. This solves the problems of residual stress at the contact interface between the piezoelectric sheet and the upper and lower electrodes, and the leakage of acoustic wave energy from the boundaries of the piezoelectric sheet and the electrodes. Furthermore, the gap between the piezoelectric sheet and the upper and lower electrodes forms a sound wave reflection interface. When longitudinal sound waves propagate from the piezoelectric sheet to the air interface where the gap is located, the sound waves are reflected back into the piezoelectric sheet, reducing longitudinal sound wave loss. The isolation cavity exposes the boundaries of the piezoelectric sheet to the air. When transverse sound waves propagate to the boundaries of the piezoelectric sheet, the air interface in the isolation cavity reflects the sound waves back into the piezoelectric sheet, reducing transverse sound wave loss. The interconnected isolation cavities and gaps increase the contact area between the piezoelectric sheet and the air interface, which can better reduce sound wave energy loss and improve the quality factor of the resonator.

[0025] Furthermore, the lower electrode's boundary partially terminates within the area enclosed by the isolation cavity, and there is no overlap with the upper electrode in the vertical direction, reducing parasitic effects. Additionally, when sound waves propagate into the lower electrode, and then to the end of the lower electrode located below the isolation cavity, the air interface reflects the sound waves back into the lower electrode, reducing sound wave loss and improving the resonator's quality factor.

[0026] Furthermore, a capping layer is placed on the surface of the electrode with through holes (such as the upper electrode) to isolate the cavity from the external environment. This can protect the piezoelectric layer and the tiny gaps from being affected by external substances. In addition, the capping layer combined with the upper electrode enhances the structural strength of the upper electrode and improves the yield of the resonator.

[0027] Furthermore, on the first conductive plug side, the upper and lower electrodes have no opposing parts, so there will be no parasitic effect; the second conductive plug electrically connects the upper and lower electrodes outside the effective working area of ​​the resonator, so that the upper and lower electrodes are short-circuited, and there is no potential difference between the upper and lower piezoelectric sheet, which reduces the parasitic effect of the overlapping area (upper electrode, piezoelectric sheet, and lower electrode) outside the effective resonant area.

[0028] Furthermore, integrating a first active and / or a first passive microdevice in the first substrate can improve the device integration level.

[0029] Furthermore, the sacrificial layer material in the first gap, the second gap, and the isolation cavity is all made of amorphous carbon, and through holes are formed above the sacrificial layer material to facilitate the one-time removal of the sacrificial material.

[0030] Furthermore, an acoustic temperature coefficient compensation layer with a positive temperature coefficient is provided on the upper or lower surface of the piezoelectric sheet or inside the piezoelectric sheet to reduce the change of resonator frequency with temperature. By controlling the thickness of the acoustic temperature coefficient compensation layer, the resonator can achieve temperature compensation while minimizing the reduction of electromechanical coupling coefficient.

[0031] The method for forming a resonator according to the present invention has high process reliability and simple process. Attached Figure Description

[0032] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0033] Figure 1 A schematic diagram of a conventional thin-film piezoelectric acoustic resonator is shown.

[0034] Figure 2 A schematic diagram of another existing thin-film piezoelectric acoustic resonator is shown.

[0035] Figure 3 A three-dimensional schematic diagram of a thin-film piezoelectric acoustic resonator according to a first embodiment of the present invention is shown; the main three-layer structure of the resonator is mainly shown.

[0036] Figure 4 for Figure 3 A sectional view along the XX direction.

[0037] Figure 5 A structural schematic diagram showing the location of the through hole according to an embodiment of the present invention is shown.

[0038] Figure 6 A schematic diagram of a thin-film piezoelectric acoustic resonator according to another embodiment of the present invention is shown.

[0039] Figure 7 A schematic diagram of a thin-film piezoelectric acoustic resonator according to a second embodiment of the present invention is shown.

[0040] Figure 8 A flowchart illustrating a method for manufacturing a thin-film piezoelectric acoustic resonator according to an embodiment of the present invention is shown.

[0041] Figures 9 to 25 The diagram shows structural schematics corresponding to different steps in the manufacturing method of a thin-film piezoelectric acoustic resonator according to a first embodiment of the present invention.

[0042] Figure 26 A schematic diagram of the manufacturing process of a thin-film piezoelectric acoustic resonator according to a second embodiment of the present invention is shown.

[0043] Explanation of reference numerals in the attached figures:

[0044] Figure 1 middle

[0045] R10 - Substrate; R20 - Cavity; R30 - Upper electrode sheet; R50 - Lower electrode sheet; R40 - Thin film piezoelectric sheet; R41 - Upper surface; R42 - Lower surface; R31 - Air interface; R51 - Air interface.

[0046] Figure 2 middle

[0047] R110 - Substrate; R120 - First electrode; R140 - Piezoelectric layer; R160 - Second electrode; R115 - Acoustic reflection structure; R130 - Gap; R150 - Gap; R141 - Air interface; R142 - Air interface.

[0048] Figures 3 to 26 middle

[0049] 50-First substrate; 41-First dielectric layer; 31-Second dielectric layer; 30-Piezoelectric sheet; 21-Third dielectric layer; 20-Upper electrode; 40-Lower electrode; 61-First conductive plug; 62-Second conductive plug; 63-Third conductive plug; 311-First gap; 33-Trench; 34-Third sacrificial layer; 35-First sacrificial layer; 36-Acoustic temperature compensation sheet; 211-Second gap; 23-Second sacrificial layer; 300-Isolation cavity; 301-Connecting bridge; 302-End; 303-Outer side of effective working area; 13-Through hole; 14-Isolation trench; 12-Top film layer; 11-Fourth dielectric layer; 110-Capping layer; 32-First groove; 22-Second groove; 60-Second substrate; 70-Microdevice; 71-MIM capacitor; 72-MOS transistor; 73-Inductor. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and drawings. However, it should be noted that the concept of the technical solution of the present invention can be implemented in many different forms and is not limited to the specific embodiments described herein. The accompanying drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0051] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0052] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0053] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0054] If the method described herein comprises a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which these steps can be performed, and some steps may be omitted and / or other steps not described herein may be added to the method. If a component in one of the figures is the same as a component in another figure, although these components are easily identifiable in all figures, this specification will not label all identical components in every figure for the sake of clarity of description.

[0055] Example 1, First type of thin-film piezoelectric acoustic resonator:

[0056] One embodiment of the present invention provides a thin-film piezoelectric acoustic resonator. Figure 3 A simplified three-dimensional schematic diagram of a thin-film piezoelectric acoustic resonator according to an embodiment of the present invention is shown. Figure 4 for Figure 3 Please refer to the sectional view along the XX direction. Figure 3 and Figure 4 Thin-film piezoelectric acoustic resonators include:

[0057] First substrate 50;

[0058] The upper electrode 20, the piezoelectric sheet 30 and the lower electrode 40 are disposed on the upper surface of the first substrate 50 and stacked sequentially from top to bottom;

[0059] The upper electrode 20, the piezoelectric sheet 30, and the lower electrode 40 have overlapping areas in a direction perpendicular to the surface of the piezoelectric sheet 30;

[0060] Within the overlapping area, a second gap 211 is provided between the piezoelectric sheet 30 and the upper electrode 20, and a first gap 311 is provided between the piezoelectric sheet 30 and the lower electrode 40;

[0061] An isolation cavity 300 surrounds the outer periphery of the piezoelectric sheet body 30, and at least one connecting bridge 301 (shown in the dashed box) is provided between the piezoelectric sheet body 30 and the first substrate 50.

[0062] The working principle of the bulk acoustic wave resonator is based on the vibration generated by the piezoelectric sheet 30 under an alternating electric field. This vibration excites a bulk acoustic wave that propagates along the thickness direction of the piezoelectric sheet 30. When this acoustic wave reaches the reflecting interface, it is reflected back, and then reflects back and forth inside the piezoelectric sheet 30, forming an oscillation. When the acoustic wave propagates in the piezoelectric sheet 30 for an odd multiple of half the wavelength, a standing wave oscillation is formed. The area where the upper electrode 20, the piezoelectric sheet 30, and the lower electrode 40 overlap in the direction perpendicular to the surface of the piezoelectric sheet 30 is the region where the bulk acoustic wave is generated, hereinafter referred to as the effective working area.

[0063] refer to Figure 4 When an alternating radio frequency voltage signal is applied to the upper electrode 20 and the lower electrode 40, the electric field lines need to pass through the first gap 311, the piezoelectric sheet 30, and the second gap 211. Therefore, the height of the first gap 311 and the second gap 211 is crucial, generally between 0.1 nanometers and 5 micrometers. Specifically, the optimal height of the first gap 311 and the second gap 211 is determined by the principle of maximizing piezoelectric interaction between the upper electrode 20 and the lower electrode 40 and the piezoelectric sheet 30, while ensuring that the upper or lower surface of the piezoelectric sheet 30 does not touch the upper electrode 20 and the lower electrode 40 when it generates piezoelectric acoustic wave vibrations. If the gap is too large, the coupling between the upper and lower electrodes and the piezoelectric sheet will weaken; if the gap is too small, the acoustic wave vibrations of the piezoelectric sheet, especially in the vertical direction, will cause the piezoelectric sheet to touch the surfaces of the upper and lower electrodes. The first gap 311 and the second gap 211 form a sound wave reflection interface. When the longitudinal sound wave in the piezoelectric sheet 30 is transmitted to the air interface where the first gap 311 or the second gap 211 is located, the sound wave is reflected back into the interior of the piezoelectric sheet 30, reducing the loss of longitudinal sound waves and improving the quality factor of the resonator.

[0064] The presence of the first gap 311 means that the lower electrode does not contact the piezoelectric sheet, and the flatness requirement for the upper surface of the lower electrode is not high. This reduces the process requirements for the lower electrode 40 and eliminates the process step of adjusting the surface thickness of the upper surface of the lower electrode.

[0065] The fact that the first gap 311 and the second gap 211 are located within the effective working area can be understood as: a portion of the effective working area is provided with the first gap 311 and the second gap 211, or the entire effective working area is provided with the first gap 311 and the second gap 211.

[0066] The isolation cavity 300 is used to isolate the piezoelectric sheet 30, exposing a portion of the edge of the piezoelectric sheet 30 within the isolation cavity 300. When sound waves propagate to the boundary of the piezoelectric sheet 30, the sound waves are reflected back into the piezoelectric sheet 30 by the air interface of the isolation cavity 300, reducing lateral sound leakage and improving the quality factor of the resonator. The edge shape of the piezoelectric sheet 30 exposed in the isolation cavity 300 includes arcs or straight lines. For example, the edge shape can be composed of one or more arcs, a combination of arcs and straight lines, or multiple straight lines. The edge of the piezoelectric sheet 30 mentioned here refers to the edge of the piezoelectric sheet 30 located in the effective working area. The piezoelectric sheet in the effective working area can be selected as an irregular polygon, and any two sides of the polygon are not parallel.

[0067] In this embodiment, the isolation cavity 300 is a continuous whole, surrounding part of the edge of the piezoelectric sheet 30. The portion of the piezoelectric sheet not surrounded by the isolation cavity 300 that extends above the first substrate 50 constitutes the connecting bridge 301.

[0068] In another embodiment, the isolation cavity 300 comprises multiple spaced sub-cavities, and the portion of the piezoelectric sheet 30 extending above the first substrate 50 between adjacent sub-cavities constitutes the connecting bridge 301. The connecting bridge is used to connect and fix the piezoelectric sheet 30 to the first substrate 50. The distribution and shape of the connecting bridge are designed to stably support the piezoelectric sheet 30. Various forms are possible; for example, the isolation cavity 300 may form a pentagonal shape with the edges of the piezoelectric sheet 30, and the connecting bridge 301 may be located at the five vertices of the pentagon.

[0069] In this invention, the isolation cavity can also be a cavity that is closed along the circumference. In this case, the connecting bridge can span over the isolation cavity and connect between the piezoelectric sheet and the first substrate. At this time, the outer periphery of the piezoelectric sheet is in contact with the air, which can better prevent transverse sound wave leakage.

[0070] In this embodiment, the isolation cavity 300, the first gap 311, and the second gap 211 are interconnected. When forming the isolation cavity 300, the first gap 311, and the second gap 211, a sacrificial layer needs to be filled within them. Since the three spaces are interconnected, the sacrificial layer in all three spaces can be removed at once, simplifying the manufacturing process. Furthermore, the interconnection between the isolation cavity 300, the first gap 311, and the second gap 211 increases the contact area between the piezoelectric sheet 30 and the air interface, which can better reduce acoustic energy loss and improve the quality factor of the resonator.

[0071] The thickness of the piezoelectric sheet 30 is from 0.01 micrometers to 10 micrometers, and different thicknesses can be selected according to the specific set frequency. The material of the piezoelectric sheet 30 can be an oxide, nitride, or carbide, such as aluminum nitride (AlN), zinc oxide (ZnO), or a piezoelectric crystal or piezoelectric ceramic, such as lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz, potassium niobate (KNbO3), lithium tantalate (LiTaO3), lithium gallium oxide, lithium germanate, titanium germanate, or lead zinc sphene, etc., piezoelectric materials with wurtzite-type crystal structures, and combinations thereof. When the piezoelectric sheet 102 includes aluminum nitride (AlN), the piezoelectric sheet 102 may also include at least one of rare earth metals, such as scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). In addition, when the piezoelectric sheet body 102 includes aluminum nitride (AlN), the piezoelectric sheet body 102 may also include at least one of transition metals, such as scandium (Sc), zirconium (Zr), titanium (Ti), manganese (Mn) and hafnium (Hf).

[0072] Reference Figure 4 In this embodiment, a first dielectric layer 41 is further provided on the upper surface of the first substrate 50, and the lower electrode 40 is embedded in the first dielectric layer 41, with the first gap 311 exposing the upper surface of the lower electrode 40; the end 302 of the lower electrode 40 overlaps with the isolation cavity 300. A portion of the edge of the lower electrode lies within or outside the area enclosed by the isolation cavity in a direction perpendicular to the surface of the piezoelectric sheet. Figure 4 The lower electrode 40's end 302, i.e., part of the boundary, is completely located below the isolation cavity.

[0073] Specifically, the first dielectric layer 41 encloses the lower electrode 40, protecting it. The end 302 of the lower electrode 40 is located below the isolation cavity 300, meaning that a portion of the lower electrode 40's boundary terminates within the area enclosed by the isolation cavity 300. In this case, the outer side 303 of the effective working area (the area indicated by the dashed line in the figure) does not overlap with the upper electrode 20 in the vertical direction, reducing parasitic effects. Furthermore, when sound waves propagate into the lower electrode 40, and reach the end of the lower electrode 40 located below the isolation cavity 300, the air interface reflects the sound waves back into the lower electrode 40, reducing sound wave loss and improving the resonator's quality factor.

[0074] Continue to refer to Figure 4 In this embodiment, the upper electrode 20 above the second gap 211 is provided with at least one through hole 13, and the upper surface of the upper electrode 20 is also provided with a capping layer 110, which fills the through hole 13. The through hole 13 is a sacrificial hole used to release the sacrificial layer filled in the first gap, the second gap, and the isolation cavity.

[0075] refer to Figure 5 In another embodiment, since the first gap, the second gap, and the isolation space 300 are connected, the through hole 13 may only penetrate the upper structure of the isolation space 300.

[0076] In this embodiment, the cap layer 110 is a composite structure, including a fourth dielectric layer 11 and a top film layer 12 located on the upper surface of the fourth dielectric layer 11. Both the fourth dielectric layer 11 and the top film layer 12 are insulating materials. The material of the fourth dielectric layer 11 can be silicon dioxide or silicon nitride, and the material of the top film layer 12 can be an organic curing film. In this embodiment, the through hole 13 also penetrates the fourth dielectric layer 11, which is used to protect the upper electrode 20 during the manufacture of the resonator. The material of the top film layer 12 can be an organic curing film or a silicon dioxide layer. The top film layer 12 serves to seal the through hole 13 and also strengthens the support for the upper electrode 20.

[0077] There is a dielectric layer between the lower electrode 40 outside the first gap 311 and the piezoelectric sheet 30, or the lower electrode 40 outside the first gap 311 is in contact with the piezoelectric sheet 30; and / or, there is a dielectric layer between the upper electrode 20 outside the second gap 211 and the piezoelectric sheet 30, or the upper electrode 20 is in contact with the piezoelectric sheet 30.

[0078] Specifically, refer to Figure 4 In this embodiment, a second dielectric layer 31 is provided between the lower electrode 40 and the piezoelectric sheet 30. The first gap 311 is located inside the second dielectric layer 31, and the second dielectric layer 31 defines the area of ​​the first gap 311. The second dielectric layer 31 is configured such that the lower surface of the piezoelectric sheet 30 exposed in the first gap 311 is flush with the lower surface of the piezoelectric sheet 30 not exposed in the first gap 311. The height of the second dielectric layer 31 determines the height of the first gap 311. Similarly, a third dielectric layer 21 is provided between the upper electrode 20 and the piezoelectric sheet 30. The second gap 211 is located inside the third dielectric layer 21, and the third dielectric layer 21 defines the area of ​​the second gap 211. The third dielectric layer 21 is configured such that the lower surface of the piezoelectric sheet 30 exposed in the second gap 211 is flush with the lower surface of the piezoelectric sheet 30 not exposed in the second gap 211. The height of the third dielectric layer 21 determines the height of the second gap 211.

[0079] The materials of the first dielectric layer 41, the second dielectric layer 31, and the third dielectric layer 21 mentioned above include silicon dioxide or silicon nitride.

[0080] The first substrate 10 may be a semiconductor substrate or a semiconductor substrate and a dielectric layer thereon, wherein the dielectric layer is a film layer formed on the semiconductor substrate when other device structures are formed on the semiconductor substrate. The semiconductor substrate may be made of at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), silicon carbide (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III / V compound semiconductors, or silicon on dielectric (SOI), silicon on dielectric (SSOI), silicon germanium on dielectric (S-SiGeOI), silicon germanium on dielectric (SiGeOI), and germanium on dielectric (GeOI), or it may be a double-sided polished wafer (DSP), or a ceramic substrate such as alumina, a quartz or glass substrate, etc. The dielectric materials on the semiconductor substrate include: silicon oxide, silicon nitride, silicon carbide, silicon oxycarbide, silicon oxynitride, aluminum oxide, aluminum nitride, or boron nitride.

[0081] In this embodiment, on the outer periphery of the region enclosed by the isolation cavity and the first and second gaps, the upper electrode and the lower electrode are offset on the side where the partial edge is located, and have opposing portions on opposite sides of the partial edge. The resonator further includes: a first conductive plug 61, connected to the upper electrode 20 on the offset side, and penetrating the upper structure of the upper electrode 20 on the other side of the upper electrode 20 opposite to the substrate; and a second conductive plug 62, connected to the lower electrode 40 on the side with opposing portions, and penetrating the upper structure of the upper electrode 20 on the other side of the lower electrode 40 opposite to the substrate.

[0082] In this embodiment, the first conductive plug 61 is located outside the effective working area. On the side where the first conductive plug 61 is located, there is no opposing portion between the upper and lower electrodes; therefore, there is no parasitic effect between them. Furthermore, the second conductive plug 62 serves two purposes: firstly, it electrically connects the lower electrode 40 to the outside; secondly, it is also electrically connected to the upper electrode 20 on its side. Thus, it electrically connects the upper and lower electrodes outside the effective working area of ​​the resonator, short-circuiting them and eliminating the potential difference between the upper and lower piezoelectric sheet 30. This reduces the parasitic effect in the overlapping area (upper electrode, piezoelectric sheet, and lower electrode) outside the resonant region, improving the quality factor of the resonator. Based on the above description, in this embodiment, the entire resonator has virtually no parasitic capacitance effect in all ineffective regions, which greatly contributes to improving the performance of the resonator.

[0083] refer to Figure 6In another embodiment of the present invention, the thin-film piezoelectric acoustic resonator further includes an acoustic temperature compensation plate 36. The acoustic temperature compensation plate 36 can be located on the upper or lower surface of the piezoelectric plate 30, or inside the piezoelectric plate 30; the figure shows the case where it is located on the upper surface. The acoustic temperature compensation plate 36 has a positive temperature coefficient and is made of a material such as boron-doped silicon dioxide. The placement of the acoustic temperature compensation plate 36 reduces the electromechanical coupling coefficient of the resonator. The greater the thickness, the greater the impact on the electromechanical coupling coefficient. In this embodiment, its thickness can be selected from 5 nanometers to 500 nanometers, achieving temperature compensation while minimizing the reduction in the electromechanical coupling coefficient of the resonator.

[0084] In addition, continue to refer to Figure 6 In this embodiment, the first substrate 50 includes a semiconductor substrate 51 and a dielectric layer 52 located on the semiconductor substrate. The first substrate 50 has a first active and / or a first passive microdevice disposed therein. The first active microdevice includes one or a combination of a diode, a transistor, a MOS transistor, and an electrostatic discharge (ESD) protection device. Figure 6 The image shows a MOS transistor 72. Other components can be selected according to actual needs. The MOS transistor can be used to form RF subsystems such as RF switches and low-noise amplifiers, thereby enabling short-distance interconnection with filters, which can help reduce signal insertion loss and interference caused by interconnection.

[0085] The first passive microdevice includes a resistor, capacitor, or inductor, or a combination thereof. Figure 6 The figure shows MIM capacitor 71 and inductor 73. Furthermore, the MOS transistor 72, MIM capacitor 71, and inductor 73 are interconnected in a specific manner. This enables short-distance interconnection with the filter, allowing the first passive microdevice to achieve better in-situ impedance matching with the filter.

[0086] To electrically connect the first active and / or first passive microdevice 70 to the resonator, this embodiment further includes: a third conductive plug 63 located in the inactive region, one end of which is connected to the first active and / or first passive microdevice, and the other end penetrating through the structure above the microdevice (see reference). Figure 6 The microdevice is electrically connected to the upper and lower electrodes via other interconnect structures on the cap layer, connecting the third conductive plug, the first conductive plug, and the second conductive plug. However, this connection method is not limited to this one; the other end of the third plug 63 can also be connected to the upper or lower electrode, and the first active and / or first passive microdevice can be electrically connected to the upper electrode 20 or the lower electrode 40 via the third conductive plug 63. The figure illustrates the first active and first passive microdevices in a simplified form. The specific devices to be included and their interconnections need to be determined based on the actual situation.

[0087] Example 2, Second type of thin-film piezoelectric acoustic resonator:

[0088] refer to Figure 7 The main difference between this embodiment and Embodiment 1 is that the piezoelectric sheet 30 is formed directly above the lower electrode 40 without a dielectric layer in between. In this case, the lower surface of the piezoelectric sheet 30 not exposed in the first gap 311 is in direct contact with the upper surface of the lower electrode 40, while the lower surface of the piezoelectric sheet 30 exposed in the first gap 311 is not flush with the lower surface of the piezoelectric sheet 30 not exposed in the first gap 311. The height of the first gap 311 is determined by the thickness of the sacrificial layer formed on the lower electrode 40. Similarly, a dielectric layer may not be provided between the piezoelectric sheet 30 and the upper electrode 20. The bottom surfaces of the upper electrode 20 exposed above the second gap 211 and the upper electrode 20 not exposed above the second gap 211 are not flush with each other, and the lower surface of the upper electrode 20 not exposed above the second gap 211 is in direct contact with the upper surface of the piezoelectric sheet 30. For other parts not described, refer to Embodiment 1.

[0089] Example 3, Method for forming a first thin-film piezoelectric acoustic resonator:

[0090] The third embodiment of the present invention provides a method for manufacturing a thin-film piezoelectric acoustic resonator. Figure 8 A flowchart illustrating a method for manufacturing a thin-film piezoelectric acoustic resonator according to an embodiment of the present invention is shown. Figures 9 to 25 The diagram shows a schematic representation of different stages in a method for manufacturing a thin-film piezoelectric acoustic resonator according to an embodiment of the present invention. (Refer to...) Figure 8 The production method includes:

[0091] S01: Provide a first substrate, and form an upper electrode on the first substrate;

[0092] S02: A stacked structure is formed on the upper electrode, the stacked structure including: a piezoelectric sheet body, a first sacrificial layer located on the upper surface of the piezoelectric sheet body, a second sacrificial layer located on the lower surface of the piezoelectric sheet body, a third sacrificial layer located on the outer periphery of the piezoelectric sheet body, and at least one connecting bridge connecting the first substrate and the piezoelectric sheet body, wherein the first sacrificial layer and the second sacrificial layer are connected together through the third sacrificial layer;

[0093] S03: A lower electrode is formed on the stacked structure;

[0094] S04: Remove the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer to form a first gap between the piezoelectric sheet body and the lower electrode, a second gap between the piezoelectric sheet body and the upper electrode, and an isolation cavity on the outer periphery of the piezoelectric sheet body;

[0095] The upper electrode, the piezoelectric sheet, and the lower electrode have overlapping regions in a direction perpendicular to the surface of the first substrate. The first gap and the second gap are at least partially located within the overlapping regions, and the overlapping regions are defined as the effective working area.

[0096] Please refer to the following. Figures 9 to 25 The manufacturing method of the thin-film piezoelectric wave resonator is described. Figures 9 to 25 This is a schematic diagram of the structure corresponding to each step in one embodiment of the method for manufacturing a thin-film piezoelectric acoustic resonator of the present invention.

[0097] refer to Figure 9 and Figure 10 Step S01 is executed, a first substrate 10 is provided, and an upper electrode 20 is formed on the first substrate 10.

[0098] refer to Figure 9 In this embodiment, the upper electrode is a solid conductive layer, and the patterning process for forming the upper electrode is completed in a subsequent process. Before forming the upper electrode 20, a fourth dielectric layer 11 is formed on the first substrate 10. The first substrate 10 serves as a temporary support layer and needs to be removed in a later process. The fourth dielectric layer 11 acts as an isolation layer to separate the first substrate 10 from the upper electrode 20.

[0099] In another embodiment, the upper electrode is an electrode patterned from the conductive layer, the upper electrodes between adjacent resonators are disconnected from each other, and the ineffective region and effective region of the upper electrode are disconnected from each other; the method of forming the upper electrode includes: forming an upper conductive film on the first substrate; patterning the upper conductive film to form the upper electrode, wherein the end of the upper electrode overlaps with a second sacrificial layer formed in a subsequent process.

[0100] The first substrate 10 can be made of one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), silicon germanium carbide (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III / V compound semiconductors; or it can be silicon-on-dielectric (SOI), silicon-on-dielectric (SSOI), silicon-on-dielectric (S-SiGeOI), silicon-on-dielectric (SiGeOI), and germanium-on-dielectric (GeOI); or it can be a double-sided polished wafer (DSP); or it can be a ceramic substrate such as alumina, a quartz substrate, or a glass substrate. The fourth dielectric layer 11 is made of silicon dioxide or silicon nitride.

[0101] refer to Figure 10An upper conductive film is formed above the surface of the fourth dielectric layer 11. The upper conductive film can be formed by physical vapor deposition or chemical vapor deposition methods such as magnetron sputtering or evaporation.

[0102] In this embodiment, the upper conductive film layer is not patterned to form the upper electrode after it is formed. The patterning process of the upper conductive film layer is completed later. In other embodiments, the upper conductive film layer is directly patterned after it is formed to form the upper electrode 20.

[0103] The upper electrode 20 can be made of one of the following metals or an alloy thereof: molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), platinum, nickel, etc.

[0104] refer to Figures 11 to 17 Step S02 is executed to form a stacked structure on the upper electrode 20. The stacked structure includes: a piezoelectric sheet 30, a first sacrificial layer 23 located on the upper surface of the piezoelectric sheet 30, a first sacrificial layer 35 located on the lower surface of the piezoelectric sheet 30, a third sacrificial layer 34 located on the outer periphery of the piezoelectric sheet 30, and at least one connecting bridge 301 connecting the first substrate 10 and the piezoelectric sheet 30.

[0105] In this embodiment, the stacked structure is formed by the following steps:

[0106] S21: A second sacrificial layer 23 and a third dielectric layer 21 are formed on the upper electrode 20, wherein the third dielectric layer 21 defines the extent of the second sacrificial layer 23;

[0107] S22: A piezoelectric sheet 30 and a third sacrificial layer 34, at least partially surrounding the piezoelectric sheet 30 in the second sacrificial layer 23 and the third dielectric layer 21, and at least one connecting bridge 301 connecting the first substrate 10 and the piezoelectric sheet 30 are formed on the second sacrificial layer 23 and the third dielectric layer 21.

[0108] S23: A first sacrificial layer 35 and a second dielectric layer 31 are formed on the piezoelectric sheet 30, wherein the second dielectric layer 31 defines the range of the first sacrificial layer 35.

[0109] Specifically, step S21 includes:

[0110] 1. Reference Figure 11A third dielectric film is formed on the surface of the upper electrode 20, the third dielectric film is patterned, and a second groove 22 is formed through the third dielectric film. The third dielectric film outside the second groove 22 is the third dielectric layer 21.

[0111] 2. Reference Figure 12 A second sacrificial film is formed, covering the second groove 22 and the third dielectric layer 21.

[0112] 3. Pattern the second sacrificial film, remove the second sacrificial film above the third dielectric layer 21, and make the upper surface of the second sacrificial film in the second groove flush with the upper surface of the third dielectric layer 21.

[0113] The second sacrificial film in the second groove constitutes the second sacrificial layer 23.

[0114] Specifically, a third dielectric film is formed on the surface of the upper electrode 20 by physical vapor deposition or chemical vapor deposition. The third dielectric film is patterned by etching to form a second groove 22 penetrating the third dielectric film. The third dielectric film outside the second groove 22 constitutes the third dielectric layer 21. The area where the second groove 22 is located is the area for forming the second gap in subsequent processes. A second sacrificial film is formed in the second groove 22 and on the third dielectric layer 21 by vapor deposition (including evaporation, sputtering, chemical vapor deposition) or liquid deposition (including electroplating). The second sacrificial film above the third dielectric layer 21 is removed by etching. The second sacrificial film in the second groove 22 constitutes the second sacrificial layer 23. In this embodiment, the method of making the upper surface of the second sacrificial film flush with the upper surface of the third dielectric layer 21 includes: performing ion beam trimming on the surface of the second sacrificial film in the second groove 22 so that the ratio of the height of the micro-protrusions or depressions on the upper surface of the second sacrificial layer 23 to the thickness of the second sacrificial layer 23 is less than 0.1%. In later processing, a piezoelectric sheet needs to be formed on the upper surface of the second sacrificial layer 23. The flatness of the upper and lower surfaces of the piezoelectric sheet affects the overall performance of the resonator, and the surface flatness of the second sacrificial layer 23 affects the flatness of the lower surface of the piezoelectric sheet. Therefore, ion beam trimming of the upper surface of the second sacrificial layer 23 can improve the performance of the resonator.

[0115] It should be noted that photoresist is required as a mask when etching away the second sacrificial film above the third dielectric layer 21. After the etching process is completed, the photoresist needs to be removed. This removal is typically done using a wet process, such as a mixture of sulfuric acid and hydrogen peroxide. Using a dry process to remove the photoresist would simultaneously remove the second sacrificial layer 23.

[0116] Step S22 includes:

[0117] 1. Reference Figure 13 A piezoelectric sensing film is formed on the second sacrificial layer 23 and the third dielectric layer 21.

[0118] 2. Reference Figure 14 A second dielectric film is formed on the piezoelectric sensing film; the second dielectric film is patterned to form a first groove 32 penetrating the second dielectric film, and the patterned second dielectric film is the second dielectric layer 31.

[0119] 3. Reference Figure 15 The piezoelectric sensing film in the first groove 32 is patterned to form a groove 33 that disconnects the piezoelectric sensing film. The bottom of the groove 33 exposes a portion of the second sacrificial layer 23. The portion of the piezoelectric sensing film that is not disconnected by the groove 33 constitutes the connecting bridge 301. The groove 33 cuts the piezoelectric sensing film to form a piezoelectric sheet 30. A portion of the end of the piezoelectric sheet 30 is exposed in the groove 33. The groove 33 is used to form an isolation cavity in a later process. The shape and position of the groove 33 and the piezoelectric sheet 30 refer to the relationship between the isolation cavity and the piezoelectric sheet in the first embodiment, which will not be repeated here.

[0120] 4. Reference Figure 16 A third sacrificial film is formed, covering the trench 33 and the piezoelectric sensing sheet 30.

[0121] 5. Remove the third sacrificial film on the outer periphery of the trench, and make the upper surface of the third sacrificial film in the trench flush with the upper surface of the piezoelectric sheet 30; the third sacrificial film in the trench constitutes the third sacrificial layer 34.

[0122] Specifically, a piezoelectric sensing film 30 with a thickness of 0.01 micrometers to 10 micrometers is formed on the second sacrificial layer 23 and the third dielectric layer 21 by physical vapor deposition or chemical vapor deposition. The material of the piezoelectric sensing film is as described above. In this embodiment, after forming the piezoelectric sensing film, the surface of the upper surface of the piezoelectric sensing film is further smoothed by an ion beam trimming process, so that the ratio of the height of the micro-protrusions or depressions on the upper surface of the piezoelectric sensing film to the thickness of the piezoelectric sensing film is less than 0.1%. The smoothness of the upper and lower surfaces of the piezoelectric sheet affects the overall performance of the resonator. Ion beam trimming of the upper surface of the piezoelectric sheet 30 can improve the performance of the resonator.

[0123] A second dielectric film is formed on the piezoelectric sensing film 30 by physical or chemical vapor deposition. A first groove 32 penetrating the second dielectric film is formed in the second dielectric film by etching. The area where the first groove 32 is located is the area where the first gap is located in the subsequent process. The piezoelectric sensing film 30 in the first groove 32 is patterned to form a trench 33 that breaks the piezoelectric sensing film. The bottom of the trench 33 exposes a portion of the second sacrificial layer 23. The exposure of a portion of the second sacrificial layer 23 at the bottom of the trench 33 allows the first gap and the isolation cavity formed in the subsequent process to communicate with each other. When the trench 33 is a non-closed trench, the portion of the piezoelectric sensing film that is not broken by the trench 33 constitutes the connecting bridge 301. The shape, position, and function of the connecting bridge 301 are as described above.

[0124] refer to Figure 16 A third sacrificial film is formed in the trench, on the upper surface of the piezoelectric sheet 30, and on the upper surface of the second dielectric layer 31 by a deposition process. The third sacrificial film on the outer periphery of the trench is removed by an etching process, while the third sacrificial film in the trench is retained as the third sacrificial layer, and the upper surface of the third sacrificial layer 34 in the trench is flush with the upper surface of the piezoelectric sheet 30; the third sacrificial film in the trench constitutes the third sacrificial layer 34.

[0125] refer to Figure 17 A first sacrificial film is formed on the upper surface of the third sacrificial layer, the first groove, and the second dielectric layer 31. The method for forming the first sacrificial film is the same as the method for forming the second sacrificial film described above. The first sacrificial film outside the first groove is removed by an etching process, and the upper surface of the first sacrificial film is made flush with the upper surface of the second dielectric layer 31. The first sacrificial film in the first groove constitutes the first sacrificial layer 35. In this embodiment, the method for making the upper surface of the first sacrificial film flush with the upper surface of the second dielectric layer 31 includes: using an ion beam trimming process to trim the surface of the first sacrificial layer 31 in the first groove to make the ratio of the height of the micro-protrusions or depressions on the upper surface of the first sacrificial layer to the thickness of the first sacrificial layer less than 0.1%. Since the material of the first sacrificial layer 35 is softer than the material of the outer peripheral second dielectric layer 31, if the CPM process is used, it is easy to cause the middle of the first sacrificial layer 35 to be recessed downwards. The ion beam trimming process can avoid the first sacrificial layer 35 from being recessed downwards and can better control the thickness of the sacrificial layer.

[0126] In this embodiment, the materials of the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer include any one of phosphosilicate glass, borosilicate glass, germanium, carbon, low-temperature silicon dioxide, and polyimide.

[0127] refer to Figure 18 A lower electrode 40 is formed on the stacked structure.

[0128] A lower conductive film is formed on the first sacrificial layer 35 and the second dielectric layer 31 using a magnetron sputtering process. The lower conductive film is then patterned to form a lower electrode 40. In this embodiment, a portion of the lower electrode 40 terminates above the third sacrificial layer. The effect of this configuration is as described above. The specific pattern of the lower electrode 40 can be set according to actual needs, such as the various scenarios described in the first embodiment, and is not limited to these examples. Figure 18 The partial boundary shown ends above the third sacrificial layer.

[0129] refer to Figures 19 to 21 In this embodiment, after forming the lower electrode 40, the process further includes forming a first dielectric layer 41 to cover the lower electrode 40; bonding a second substrate 60 onto the first dielectric layer 41, and then removing the first substrate 10; patterning the entire conductive layer to form the upper electrode 20, wherein the upper electrodes 20 between adjacent resonators are disconnected from each other, and the ineffective and effective regions of the upper electrodes 20 are disconnected from each other. (Refer to...) Figure 21 During the patterning of the upper electrode 20, a through hole 13 as a sacrificial hole and an isolation groove 14 between the two resonators are also etched.

[0130] Specifically, a first dielectric layer 41 is formed above the surface of the lower electrode 40 by a deposition process, and the top surface of the first dielectric layer 41 is flush with the surface by a planarization process.

[0131] refer to Figures 20 to 23 The first sacrificial layer, the second sacrificial layer, and the third sacrificial layer are removed to form a first gap 311 between the piezoelectric sheet 30 and the lower electrode 40, a second gap 211 between the piezoelectric sheet 30 and the upper electrode 20, and an isolation cavity 300 on the outer periphery of the piezoelectric sheet 30.

[0132] In this embodiment, the specific steps for removing the sacrificial layer are as follows:

[0133] refer to Figure 20 A second substrate 60 is bonded to the upper surface of the first dielectric layer 41, and the first substrate 10 is removed.

[0134] refer to Figures 21 to 23 This forms at least one through-hole 13 penetrating the film layer above the second sacrificial layer and / or the third sacrificial layer. The first, second, and third sacrificial layers are converted into volatile gases through a gas-phase chemical reaction and discharged through the through-hole, or the first or second sacrificial layer is dissolved in a solution through a liquid-phase chemical reaction and discharged through the through-hole. (Reference) Figure 21 Through-hole 13 penetrates the structure above the second sacrificial layer, as shown in the reference. Figure 22 The through-hole penetrates the structure above the third sacrificial layer. In this embodiment, the surface of the upper electrode 20 is provided with a fourth dielectric layer 11, and the through-hole 13 also penetrates the fourth dielectric layer 11. After removing the three sacrificial layers, the piezoelectric sheet 30 is suspended between the first gap 311 and the second gap 211, and part of the edge of the piezoelectric sheet 30 is exposed in the isolation cavity 300.

[0135] It should be noted that when forming the through hole 13, an isolation groove 14 is formed between the two resonators to achieve electrical isolation between the two adjacent resonators.

[0136] refer to Figure 24 A top film layer 12 is formed on the fourth dielectric layer 11. The top film layer 12 seals the through hole. The material and function of the top film layer 12 are described above. In this embodiment, the fourth dielectric layer 11 and the top film layer 12 together form a capping layer. Further details are omitted here.

[0137] refer to Figure 25 In this embodiment, the outer periphery of the area enclosed by the isolation cavity 300, the first gap 311, and the second gap 211, has the upper electrode 20 and the lower electrode 40 offset on the side where the partial edge is located, and have opposing portions on opposite sides of the partial edge; the method further includes:

[0138] A first conductive plug 61 is formed, which is connected to the upper electrode 20 on one side of the offset side, and penetrates the structure above the upper electrode 20 on the other side of the upper electrode 20 opposite to the first substrate.

[0139] A second conductive plug 62 is formed, connected to the lower electrode 40 on the opposite side of the lower electrode 40 relative to the first substrate, and penetrating the upper structure above the upper electrode 20. In this embodiment, the upper structure above the upper electrode 20 includes a top film layer 12 and a fourth dielectric layer 11. The first conductive plug 61 penetrates the top film layer 12 and the fourth dielectric layer 11, and is electrically connected to the upper electrode 20. The upper structure above the lower electrode 40 includes: the top film layer 12, the fourth dielectric layer 11, the upper electrode 20, the third dielectric layer 21, the piezoelectric sheet 30, and the second dielectric layer 31. The second conductive plug 62 penetrates the top film layer 12 and the fourth dielectric layer 11, the upper electrode 20, the third dielectric layer 21, the piezoelectric sheet 30, and the second dielectric layer 31, and is connected to the lower electrode 40. The first conductive plug 61 and the second conductive plug 62 are located outside the effective operating region of the resonator. The second conductive plug 62 electrically connects the upper and lower electrodes of the non-active working area, wherein the upper electrode 20 connected to the second conductive plug 62 is separate from the upper electrode of the active working area. The second conductive plug 62 prevents a voltage difference from occurring across the non-active piezoelectric sheet, reducing parasitic effects.

[0140] refer to Figure 6 In another embodiment, the second substrate is a first substrate 50, within which first active and / or first passive microdevices are formed. The first active microdevices include diodes, MOS transistors, and simple semiconductor electrostatic discharge protection devices. The first passive microdevices include resistors, capacitors, or inductors. A third conductive plug 63 is also formed, through which the first active and / or first passive microdevices are electrically connected to the upper electrode 20 or the lower electrode 40. Different first active and / or first passive microdevices can be integrated according to design requirements. Integrating first active and / or first passive microdevices in the second substrate can improve the integration density of the device, reducing the overall size of the integrated RF microsystem while improving its insertion loss and anti-interference performance.

[0141] form Figure 6 The method of illustrating the third conductive plug 63 can be formed after the first conductive plug and the second conductive plug are formed, or before the first conductive plug and the second conductive plug are formed.

[0142] This embodiment illustrates the example of the upper electrode 20 being formed on the first substrate without patterning. In this invention, the upper electrode 20 can be a patterned electrode formed on the first substrate. In this case, the capping layer and the vias released as sacrificial layers are not formed on the upper electrode 20, but should be formed on the lower electrode 40.

[0143] Therefore, in this invention, the method for removing the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer includes: forming at least one via through a film layer above the sacrificial layer that extends away from the retained substrate; for example, in the first embodiment, the sacrificial layer is the first sacrificial layer. If the upper electrode is not patterned on the first substrate, the first substrate needs to be removed, and the second substrate is retained; if the upper electrode is not patterned on the first substrate, the retained substrate is the first substrate, and the second substrate is not needed. In the absence of a second substrate, the sacrificial layer is the second sacrificial layer. A capping layer is formed on the surface of the electrode where the via is formed, and the capping layer fills the via. When the retained substrate is the first substrate, the via is formed on the lower electrode, and the capping layer is formed on the lower electrode.

[0144] See Figure 26 In another embodiment, no dielectric layer is provided on the upper and lower surfaces of the piezoelectric sheet, forming the stacked structure as follows:

[0145] A second sacrificial layer 23 is formed on the upper electrode 20;

[0146] A piezoelectric sensing film is formed to cover the upper electrode 20, the second sacrificial layer 23, and the first substrate 10;

[0147] The piezoelectric sensing film is patterned to form a trench that disconnects the piezoelectric sensing film. A portion of the second sacrificial layer 23 is exposed at the bottom of the trench. The portion of the piezoelectric sensing film that is not disconnected by the trench constitutes the connecting bridge.

[0148] The third sacrificial layer 34 is formed in the trench, and the upper surface of the third sacrificial layer 34 is flush with the upper surface of the piezoelectric sheet 30.

[0149] A first sacrificial film is formed to cover the third sacrificial layer 34 and the piezoelectric sheet 30;

[0150] The first sacrificial film is patterned, and the first sacrificial film outside the second region is removed. The second region is located within the effective working area, and the first sacrificial film in the second region constitutes the first sacrificial layer 35.

[0151] Specifically, a second sacrificial film is formed on the upper electrode 20, covering the upper electrode 20. The second sacrificial film is patterned to form a second sacrificial layer 23, which is located in the effective working area. The position of the second sacrificial layer 23 is used to form a second gap. The thickness of the second sacrificial layer is the height of the second gap, and can be selected from 0.1 nanometers to 5 nanometers. The material of the second sacrificial layer 23 is as described above. A piezoelectric sensing film is formed on the second sacrificial layer 23 and the upper electrode 20 using a deposition process. The thickness of the piezoelectric sensing film is between 0.1 and 10 micrometers, and the material of the piezoelectric sensing film is as described above. A trench is formed in the piezoelectric sensing film by an etching process to disconnect the piezoelectric sensing film. The trench defines the boundary of the edge of the piezoelectric sheet 30. In this embodiment, the bottom of the trench exposes part of the second sacrificial layer 23, and the portion of the piezoelectric sensing film not disconnected by the trench constitutes the connecting bridge. The shape and distribution of the trench, the shape of the piezoelectric sheet 30, and the positional distribution of the connecting bridge are the same as in the previous embodiment, and will not be repeated here. A third sacrificial film is formed to cover the trench and the upper surface of the piezoelectric sheet 30. The third sacrificial film outside the trench is removed to form a third sacrificial layer 34. A first sacrificial film is formed to cover the third sacrificial layer 34 and the upper surface of the piezoelectric sheet 30. The first sacrificial film is patterned, and the first sacrificial film outside the second region is removed. The second region is located within the effective working area and is the area where the first gap is located. The first sacrificial film in the second region constitutes the first sacrificial layer 35. The material and thickness of the first sacrificial film are the same as those of the third sacrificial film.

[0152] For other information regarding the removal of the sacrificial layer and the formation of the capping layer, please refer to the relevant descriptions in the method of the previous embodiment.

[0153] It should be noted that the various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for structural embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments.

[0154] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A thin-film piezoelectric acoustic resonator, characterized in that, include: First substrate; The upper electrode, piezoelectric sheet, and lower electrode are disposed on the upper surface of the first substrate and stacked sequentially from top to bottom; The upper electrode, piezoelectric sheet, and lower electrode have overlapping areas in a direction perpendicular to the surface of the piezoelectric sheet; Within the overlapping area, a first gap is provided between the piezoelectric sheet and the upper electrode, and a second gap is provided between the piezoelectric sheet and the lower electrode; An isolation cavity surrounds the outer periphery of the piezoelectric sheet, and at least one connecting bridge is provided between the piezoelectric sheet and the substrate; the isolation cavity is used to isolate the piezoelectric sheet, and when sound waves are transmitted to the boundary of the piezoelectric sheet, the sound waves are reflected back into the piezoelectric sheet by the air interface of the isolation cavity; at least a portion of the boundary of the piezoelectric sheet is formed by the isolation cavity, and the shape of the edge of the piezoelectric sheet exposed by the isolation cavity includes one or more arcuate and / or straight edges; The first gap and the second gap are connected through the isolation cavity; A portion of the edge of the lower electrode lies within the area enclosed by the isolation cavity in a direction perpendicular to the surface of the piezoelectric sheet. On the outer periphery of the area enclosed by the isolation cavity and the first gap and the second gap, the upper electrode and the lower electrode are offset on the side where the partial edge is located, and have opposite portions on the opposite sides of the partial edge; The resonator also includes: A first conductive plug is connected to the upper electrode on one side of the offset side and penetrates the structure above the upper electrode on the other side of the upper electrode opposite to the substrate. The second conductive plug is connected to the lower electrode on the side with a relative portion, and extends through the structure above the upper electrode on the other side of the lower electrode opposite to the substrate.

2. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, It also includes an acoustic temperature compensation plate, which is located on the upper or lower surface of the piezoelectric plate or inside the piezoelectric plate.

3. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The piezoelectric sheet is polygonal, and any two sides of the polygon are not parallel.

4. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The portion of the piezoelectric sheet that is not cut off by the isolation cavity constitutes the connecting bridge.

5. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The height of the first gap or the second gap is from 0.1 nanometers to 5 micrometers.

6. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The thickness of the piezoelectric sheet is from 0.01 micrometers to 10 micrometers.

7. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, It also includes at least one through hole, which is disposed above the first gap or above the isolation cavity.

8. The thin-film piezoelectric acoustic resonator as described in claim 7, characterized in that, The upper surface of the upper electrode is also provided with a capping layer, which fills the through hole.

9. The thin-film piezoelectric acoustic resonator as described in claim 8, characterized in that, The capping layer is made of one or a combination of two of the following materials: silicon dioxide, silicon nitride, and organic curing film.

10. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, There is a dielectric layer between the lower electrode outside the second gap and the piezoelectric sheet, or the lower electrode outside the second gap is in contact with the piezoelectric sheet. And / or, the upper electrode outside the first gap has a dielectric layer between it and the piezoelectric sheet, or the upper electrode is in contact with the piezoelectric sheet.

11. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, Also includes: A first dielectric layer, wherein the lower electrode is embedded in the first dielectric layer and the second gap exposes the upper surface of the lower electrode.

12. The thin-film piezoelectric acoustic resonator as described in claim 11, characterized in that, Also includes: A second dielectric layer, the second dielectric layer defining the region of the second gap; The second dielectric layer is located between the piezoelectric sheet and the lower electrode outside the second gap.

13. The thin-film piezoelectric acoustic resonator as described in claim 12, characterized in that, Also includes: A third dielectric layer, wherein the third dielectric layer defines the region of the first gap; The third dielectric layer is located between the piezoelectric sheet and the upper electrode outside the second gap.

14. The thin-film piezoelectric acoustic resonator according to any one of claims 10-13, characterized in that, The material of the dielectric layer includes silicon dioxide or silicon nitride.

15. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The first substrate includes a semiconductor substrate or a semiconductor substrate and a dielectric layer located on the semiconductor substrate.

16. The thin-film piezoelectric acoustic resonator as described in claim 1, characterized in that, The first substrate has a first active and / or first passive microdevice embedded inside it, and the resonator further includes: A third conductive plug located in the invalid region, one end of which is connected to the first active microdevice and / or the first passive microdevice, and the other end of which penetrates the structure above the microdevice; or, the other end of which is connected to the upper electrode or the lower electrode.

17. The thin-film piezoelectric acoustic resonator as described in claim 16, characterized in that, The first active microdevice includes a diode, a transistor, a MOS transistor, or an electrostatic discharge protection device.

18. The thin-film piezoelectric acoustic resonator as described in claim 16, characterized in that, The first passive microdevice includes a resistor, capacitor, or inductor.

19. A filter, characterized in that, It includes the resonators described in any one of claims 1-18.

20. A method for manufacturing a thin-film piezoelectric acoustic resonator, characterized in that, include: Provide a first substrate; An upper electrode is formed on the first substrate; A stacked structure is formed on the upper electrode, the stacked structure comprising: a piezoelectric sheet body, a first sacrificial layer located on the upper surface of the piezoelectric sheet body, a second sacrificial layer located on the lower surface of the piezoelectric sheet body, a third sacrificial layer located on the outer periphery of the piezoelectric sheet body, and at least one connecting bridge connecting the first substrate and the piezoelectric sheet body; the first sacrificial layer and the second sacrificial layer are connected together through the third sacrificial layer; A lower electrode is formed on the stacked structure; The first sacrificial layer, the second sacrificial layer, and the third sacrificial layer are removed to form a first gap between the piezoelectric sheet and the lower electrode, a second gap between the piezoelectric sheet and the upper electrode, and an isolation cavity on the outer periphery of the piezoelectric sheet. The isolation cavity is used to isolate the piezoelectric sheet, and when sound waves are transmitted to the boundary of the piezoelectric sheet, the sound waves are reflected back into the piezoelectric sheet by the air interface of the isolation cavity. At least a portion of the boundary of the piezoelectric sheet is formed by the isolation cavity, and the shape of the edge of the piezoelectric sheet exposed by the isolation cavity includes one or more arcuate and / or straight edges. The upper electrode, the piezoelectric sheet, and the lower electrode have overlapping regions in a direction perpendicular to the surface of the first substrate. The first gap and the second gap are at least partially located within the overlapping regions, and the overlapping regions are defined as the effective working area. A portion of the edge of the lower electrode lies within the area enclosed by the isolation cavity in a direction perpendicular to the surface of the piezoelectric sheet. On the outer periphery of the area enclosed by the isolation cavity and the first gap and the second gap, the upper electrode and the lower electrode are offset on the side where the partial edge is located, and have opposite portions on the opposite sides of the partial edge; The method further includes: A first conductive plug is formed, the upper electrode is connected on one side of the offset, and the structure above the upper electrode is penetrated on the other side of the upper electrode opposite to the substrate. A second conductive plug is formed, which is connected to the lower electrode on the side with a relative portion, and extends through the structure above the upper electrode on the other side of the lower electrode opposite to the substrate.

21. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The formation of the stacked structure includes: A second sacrificial layer and a third dielectric layer are formed on the upper electrode, wherein the third dielectric layer defines the extent of the second sacrificial layer. A piezoelectric sheet body is formed on the second sacrificial layer and the third dielectric layer, and the third sacrificial layer at least partially surrounds the piezoelectric sheet body in the overlapping region, and at least one connecting bridge connects the first substrate and the piezoelectric sheet body; A first sacrificial layer and a second dielectric layer are formed on the piezoelectric sheet, wherein the second dielectric layer defines the extent of the first sacrificial layer.

22. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 21, characterized in that, The formation of the second sacrificial layer and the third dielectric layer includes: A third dielectric film is formed on the surface of the upper electrode, the third dielectric film is patterned, and a second groove is formed penetrating the third dielectric film; A second sacrificial film is formed to cover the second groove and the third dielectric film; Remove the second sacrificial film above the third dielectric film, and make the upper surface of the second sacrificial film in the second groove flush with the upper surface of the third dielectric layer; The second sacrificial film in the second groove constitutes the second sacrificial layer, and the third dielectric film outside the second sacrificial layer is the third dielectric layer.

23. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 21, characterized in that, The piezoelectric sheet body and the third sacrificial layer at least partially surrounding the piezoelectric sheet body, and at least one connecting bridge connecting the first substrate and the piezoelectric sheet body, and the first sacrificial layer and the second dielectric layer include: A piezoelectric sensing film is formed on the second sacrificial layer and the third dielectric layer; A second dielectric film is formed on the piezoelectric sensing film; The second dielectric film is patterned to form a first groove penetrating the second dielectric film; The piezoelectric sensing film in the first groove is patterned to form a trench that disconnects the piezoelectric sensing film. A portion of the first sacrificial layer is exposed at the bottom of the trench. The portion of the piezoelectric sensing film that is not disconnected by the trench constitutes the connecting bridge. A third sacrificial film is formed to cover the trench and the piezoelectric sensing film; Remove the third sacrificial film from the outer periphery of the trench, and make the upper surface of the third sacrificial film in the trench flush with the upper surface of the piezoelectric sheet; The third sacrificial film in the trench constitutes the third sacrificial layer, and the piezoelectric sensing film on the outer periphery of the third sacrificial layer constitutes the piezoelectric sheet body; A first sacrificial film is formed to cover the third sacrificial layer, the first groove, and the second dielectric layer; Remove the first sacrificial film outside the first groove, and make the upper surface of the first sacrificial film flush with the upper surface of the second dielectric layer; The first sacrificial film in the first groove is the first sacrificial layer.

24. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 23, characterized in that, The step of making the upper surface of the first sacrificial film in the first groove flush with the upper surface of the second dielectric layer includes: The surface of the first sacrificial layer is smoothed using an ion beam trimming process, so that the ratio of the height of the micro-protrusions or depressions on the surface of the first sacrificial layer to the thickness of the first sacrificial layer is less than 0.1%.

25. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 23, characterized in that, After forming the piezoelectric sensing film, the process further includes: The upper surface of the piezoelectric sensing film is smoothed to make the ratio of the height of the micro-protrusions or depressions on the upper surface of the piezoelectric sensing film to the thickness of the piezoelectric sensing film less than 0.1%.

26. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 22, characterized in that, The step of making the upper surface of the second sacrificial film flush with the upper surface of the third dielectric layer includes: The surface of the second sacrificial layer in the second groove is smoothed using an ion beam trimming process, so that the ratio of the height of the micro-protrusions or depressions on the upper surface of the second sacrificial layer to the thickness of the second sacrificial layer is less than 0.1%.

27. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 21, characterized in that, The formation of the lower electrode on the stacked structure includes: A lower conductive film is formed, covering the first sacrificial layer and the second dielectric layer; The lower conductive film is patterned to form the lower electrode, the end of which overlaps with the third sacrificial layer.

28. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The thickness of the first sacrificial layer and the second sacrificial layer is 0.1 nanometers to 5 micrometers.

29. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The upper electrode is an electrode patterned from the conductive layer. The upper electrodes between each adjacent resonator are disconnected from each other, and the ineffective region and effective region of the upper electrode are disconnected from each other. or, The upper electrode is a solid conductive layer; After forming the lower electrode, the process further includes: A first dielectric layer is formed to cover the lower electrode; A second substrate is bonded to the first dielectric layer, and then the first substrate is removed. The entire conductive layer is patterned to form the upper electrode. The upper electrodes between each adjacent resonator are disconnected from each other, and the ineffective region and effective region of the upper electrode are disconnected from each other.

30. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 29, characterized in that, The method for removing the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer includes: At least one via is formed in the film layer above the sacrificial layer that extends away from the retained substrate. The first sacrificial layer, the second sacrificial layer and the third sacrificial layer are converted into volatile gases and discharged from the via through the via by a gas-phase chemical reaction, or the first sacrificial layer or the second sacrificial layer is dissolved in a solution and discharged from the via through the via by a liquid chemical reaction.

31. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 30, characterized in that, After removing the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer, the process further includes: A capping layer is formed on the surface of the electrode where the through hole is formed, and the capping layer fills the through hole.

32. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 31, characterized in that, The capping layer is made of organic curing film or silicon dioxide, and the thickness of the capping layer is from 0.2 micrometers to 30 micrometers.

33. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The materials of the first sacrificial layer, the second sacrificial layer, and the third sacrificial layer include any one of the following: phosphosilicate glass, borosilicate glass, germanium, amorphous carbon, low-temperature silicon dioxide, and polyimide.

34. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The upper electrode is an electrode patterned from the conductive layer. The upper electrodes between each adjacent resonator are disconnected from each other, and the ineffective region and effective region of the upper electrode are disconnected from each other. The method for forming the upper electrode includes: A conductive thin film is formed on the first substrate; The upper conductive film is patterned to form the upper electrode, the end of which overlaps with the second sacrificial layer.

35. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 30, characterized in that, The retained substrate has a first active and / or a first passive microdevice embedded inside it; The method further includes: A third conductive plug is formed, one end of which is connected to the first active microdevice and / or the first passive microdevice, and the other end penetrates the structure above the microdevice; or, the other end is connected to the upper electrode or the lower electrode.

36. The method for manufacturing a thin-film piezoelectric acoustic resonator as described in claim 20, characterized in that, The formation of the stacked structure includes: A second sacrificial layer is formed on the upper electrode; A piezoelectric sensing film is formed, covering the upper electrode, the second sacrificial layer, and the first substrate; The piezoelectric sensing film is patterned to form a trench that disconnects the piezoelectric sensing film. A portion of the second sacrificial layer is exposed at the bottom of the trench. The portion of the piezoelectric sensing film that is not disconnected by the trench constitutes the connecting bridge. The third sacrificial layer is formed in the trench, and the upper surface of the third sacrificial layer is flush with the upper surface of the piezoelectric sheet. A first sacrificial film is formed, which covers the third sacrificial layer and the piezoelectric sensing film; The first sacrificial film is patterned, and the first sacrificial film outside the second region is removed. The second region is located within the effective working area, and the first sacrificial film in the second region constitutes the first sacrificial layer.

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