Thin film bulk acoustic resonator and method for manufacturing the same

Abstract

The present invention relates to a thin film bulk acoustic wave resonator and a method for manufacturing the same. The thin film bulk acoustic wave resonator comprises: a stacked first electrode, a piezoelectric layer, and a second electrode; an effective resonance region comprising an area where the first electrode, the piezoelectric layer, and the second electrode overlap in a direction perpendicular to the surface of the piezoelectric layer; and an ineffective region outside the effective resonance region; a first dielectric layer, wherein a first gap is defined between the upper surface of the first dielectric layer and the lower surface of the first electrode; a second dielectric layer, wherein a second gap is defined between the lower surface of the second dielectric layer and the upper surface of the second electrode; a first conductive protrusion, wherein one end is provided on the lower surface of the first electrode and the other end is connected to a first electrode lead portion; and a second conductive protrusion, wherein one end is provided on the upper surface of the second electrode and the other end is connected to a second electrode lead portion. The present invention can improve the quality factor of the resonator.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor device manufacturing, and in particular to a thin film bulk acoustic resonator and a manufacturing method thereof. Background Art

[0002] Since the development of analog RF communication technology in the early 1990s, RF front-end modules have gradually become core components of communications equipment. Among all RF front-end modules, filters have become the component with the fastest growth momentum and the greatest development prospects. With the rapid development of wireless communication technology and the increasing maturity of 5G communication protocols, the market has also imposed more stringent standards on various aspects of RF filter performance. The performance of the filter is determined by the resonator units that make up the filter. Among existing filters, film bulk acoustic resonators (FBARs) are one of the most suitable filters for 5G applications due to their small size, low insertion loss, high out-of-band suppression, high quality factor, high operating frequency, high power handling capacity, and good resistance to electrostatic shock.

[0003] Typically, a FBAW resonator consists of two thin-film electrodes with a piezoelectric film layer between them. Its operating principle is that the piezoelectric film layer vibrates under an alternating electric field. This vibration excites a bulk acoustic wave that propagates along the thickness of the piezoelectric film layer. This sound wave is reflected at the interface between the upper and lower electrodes and the air, and then reflects back and forth within the film, forming an oscillation. When the sound wave propagates in the piezoelectric film layer at an odd multiple of half the wavelength, it forms a standing wave oscillation.

[0004] However, the quality factor (Q) of currently manufactured cavity-type thin film bulk acoustic resonators cannot be further improved, and therefore cannot meet the requirements of high-performance radio frequency systems. Summary of the Invention

[0005] An object of the present invention is to provide a thin film bulk acoustic wave resonator and a method for manufacturing the same, which can solve the problem of low quality factor of the thin film bulk acoustic wave resonator.

[0006] In order to achieve the above object, the present invention provides a thin film bulk acoustic resonator, comprising:

[0007] A stacked first electrode, a piezoelectric layer, and a second electrode, wherein an effective resonance region includes an area where the first electrode, the piezoelectric layer, and the second electrode overlap in a direction perpendicular to a surface of the piezoelectric layer, and an ineffective region is outside the effective resonance region;

[0008] a first dielectric layer, wherein a first gap is provided between an upper surface of the first dielectric layer and a lower surface of the first electrode;

[0009] a second dielectric layer, wherein a second gap is provided between a lower surface of the second dielectric layer and an upper surface of the second electrode;

[0010] a first conductive protrusion, one end of which is disposed on the lower surface of the first electrode and the other end of which is connected to the first electrode lead-out portion;

[0011] One end of the second conductive protrusion is arranged on the upper surface of the second electrode, and the other end is connected to the second electrode lead portion.

[0012] The present invention also provides a method for manufacturing a thin film bulk acoustic resonator, comprising:

[0013] forming a first structure, the first structure comprising: a first electrode, a first sacrificial layer at least covering the first electrode, and a dielectric layer surrounding the first sacrificial layer at least on a side surface of the first sacrificial layer;

[0014] forming a first conductive protrusion, penetrating the first sacrificial layer and having one end connected to the first electrode;

[0015] forming a first electrode lead portion, one end of which is connected to the first conductive protrusion and the other end of which extends out of the effective resonance region;

[0016] forming a piezoelectric layer;

[0017] forming a second structure, the second structure comprising: a second electrode, a second sacrificial layer at least covering the second electrode, and a dielectric layer surrounding the second sacrificial layer at least on a side surface of the second sacrificial layer;

[0018] forming a second conductive protrusion, penetrating the second sacrificial layer and having one end connected to the second electrode;

[0019] forming a second electrode lead portion, one end of which is connected to the second conductive protrusion and the other end of which extends out of the effective resonance region;

[0020] The first sacrificial layer and the second sacrificial layer are removed to form the first gap and the second gap.

[0021] The beneficial effects of the present invention are:

[0022] The bulk acoustic wave resonator of the present invention connects the first electrode to an external signal via the first conductive protrusion and the first electrode lead portion, and connects the second electrode to an external signal via the second conductive protrusion and the second electrode lead portion. This increases the electrode lead-out area and impedance, suppresses the coupling effect between the electrodes, and enhances thermal conductivity. The first gap and the second gap serve as acoustic wave reflection structures to improve the quality factor of the resonator. The region where the first conductive protrusion and the second conductive protrusion are located forms an acoustic impedance mismatch region, which can cause an acoustic impedance mismatch between the boundary of the effective resonant region and the interior of the effective resonant region, thereby facilitating an improvement in the quality factor of the resonator.

[0023] Furthermore, the projections of the first conductive protrusion and the second conductive protrusion on the surface of the carrier substrate are closed or discontinuous rings, which can further suppress the transverse acoustic wave energy loss and improve the quality factor of the resonator.

[0024] Furthermore, the side edges of the first electrode and the second electrode are exposed in the gap, which can suppress shear wave loss;

[0025] Furthermore, the edge of the piezoelectric layer is exposed in the gap, which can further suppress the shear wave loss;

[0026] Furthermore, the piezoelectric layer is a complete film layer, which can ensure the piezoelectric properties of the piezoelectric layer;

[0027] In the method for manufacturing a bulk acoustic wave resonator of the present invention, the piezoelectric layer is formed on a flat electrode layer, which can make the piezoelectric layer have a better lattice orientation, improve the piezoelectric characteristics of the piezoelectric layer, and thus improve the overall performance of the resonator;

[0028] Furthermore, the first electrode layer, the piezoelectric material layer, and the second electrode layer can be etched simultaneously, saving process time;

[0029] Furthermore, the first sacrificial layer and the second sacrificial layer can be removed simultaneously or in steps, thereby improving the flexibility of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic structural diagram of a thin film bulk acoustic resonator according to embodiment 1 of the present invention is shown.

[0032] Figure 2 A schematic structural diagram of a thin film bulk acoustic resonator according to embodiment 2 of the present invention is shown.

[0033] Figure 3 A schematic structural diagram of a thin film bulk acoustic resonator according to embodiment 3 of the present invention is shown.

[0034] Figures 4 to 14 Schematic diagrams of structures corresponding to different steps of a method for manufacturing a thin film bulk acoustic resonator according to embodiment 4 of the present invention are shown.

[0035] Figures 5 to 21 Schematic diagrams of structures corresponding to different steps of a method for manufacturing a thin film bulk acoustic resonator according to embodiment 5 of the present invention are shown.

[0036] Figures 22 to 30 Schematic diagrams of structures corresponding to different steps of a method for manufacturing a thin film bulk acoustic resonator according to embodiment 6 of the present invention are shown.

[0037] Description of reference numerals:

[0038] 100-carrying substrate; 101A-a dielectric layer surrounding the first sacrificial layer at least on the side of the first sacrificial layer; 101B-a first passivation layer; 101-a first dielectric layer; 102A-a dielectric layer surrounding the second sacrificial layer at least on the side of the second sacrificial layer; 102B-a second passivation layer; 102-a second dielectric layer; 200-a temporary substrate; 201'-a first electrode layer; 201-a first electrode; 202-a piezoelectric layer; 203'-a second electrode layer; 203-a second electrode; 210-a first sacrificial layer; 220-a second sacrificial layer; 211-a first gap; 221-a second gap; 301-a first conductive protrusion; 302-a second conductive protrusion; 303-a first electrode lead-out portion; 304-a second electrode lead-out portion; 10-a first cavity; 212-a release hole. DETAILED DESCRIPTION

[0039] Currently manufactured cavity-type thin film bulk acoustic resonators suffer from shear wave loss, which prevents further improvement in the quality factor (Q), and therefore cannot meet the requirements of high-performance radio frequency systems.

[0040] The following is a detailed description of the thin film bulk acoustic resonator and its fabrication method of the present invention, in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and drawings. However, it should be noted that the technical solutions of the present invention can be implemented in a variety of different forms and are not limited to the specific embodiments described herein. The drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0041] The terms "first", "second", etc. in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a specific order or chronological sequence. It is to be understood that, where appropriate, these terms used in this manner are interchangeable, for example, to enable the embodiments of the invention described herein to operate in an order other than that described or shown herein. Similarly, if the method described herein comprises a series of steps, the order in which the steps are presented herein is not necessarily the only order in which the steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method. If a component in a particular figure is the same as a component in other figures, although these components can be easily identified in all figures, in order to make the description of the figures clearer, this specification will not mark all the same component numbers in each figure.

[0042] Example 1

[0043] Embodiment 1 of the present invention provides a thin film bulk acoustic resonator, Figure 1 This is a schematic diagram of the structure of the thin film bulk acoustic resonator according to Example 1 of the present invention. Figure 1 , the thin film bulk acoustic resonator comprises:

[0044] From bottom to top, it includes a first electrode 201, a piezoelectric layer 202, and a second electrode 203 stacked in sequence. The effective resonance region includes an area where the first electrode 201, the piezoelectric layer 202, and the second electrode 203 overlap each other in a direction perpendicular to the surface of the piezoelectric layer 202. The outside of the effective resonance region is an ineffective region.

[0045] A first dielectric layer 101, with a first gap 211 being provided between an upper surface of the first dielectric layer 101 and a lower surface of the first electrode 201;

[0046] A second dielectric layer 102, with a second gap 221 being provided between the lower surface of the second dielectric layer 102 and the upper surface of the second electrode 202;

[0047] A first conductive protrusion 301 , one end of which is disposed on the lower surface of the first electrode 201 and the other end of which is connected to the first electrode lead-out portion 303 ;

[0048] One end of the second conductive protrusion 302 is disposed on the upper surface of the second electrode 202 , and the other end is connected to the second electrode lead portion 304 .

[0049] refer to Figure 1 In this embodiment, a carrier substrate 100 is also included. The first dielectric layer 101 and the carrier substrate 100 can be combined by a bonding layer or deposition. The material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate. In this embodiment, the first dielectric layer 101 is formed on the carrier substrate 100 by deposition. The first dielectric layer can be a single-layer structure or a stacked-layer structure. The material of the first dielectric layer can include but is not limited to one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride and the like, but the technology of the present invention is not limited thereto.

[0050] The material of the carrier substrate 100 can be any suitable substrate known to those skilled in the art, for example, it can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (SiC), carbon silicon germanium (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors.

[0051] Above the first dielectric layer 101, from bottom to top, are a stacked first electrode 201, a piezoelectric layer 202, and a second electrode 203. The second electrode 202 and the first electrode 201 can be made of any suitable conductive or semiconductor material known in the art. The conductive material can be a conductive metal material, such as 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), or a stacked layer of the aforementioned metals. Semiconductor materials include, for example, Si, Ge, SiGe, SiC, and SiGeC. The material of the piezoelectric layer 202 can be a piezoelectric material having a wurtzite crystal structure, such as aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz, potassium niobate (KNbO3), or lithium tantalate (LiTaO3), or a combination thereof. When the piezoelectric layer 202 comprises aluminum nitride (AlN), the piezoelectric layer 202 may also include a rare earth metal, such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). In addition, when the piezoelectric layer 202 comprises aluminum nitride (AlN), the piezoelectric layer 202 may also include a transition metal, such as at least one of zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). The piezoelectric layer 202 can be formed by any suitable deposition method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition.

[0052] In this embodiment, the upper surface of the first dielectric layer 101 is concave in the middle and convex at the periphery. A first gap 211 is provided between the lower surface of the first electrode 201 and the upper surface of the concave region of the first dielectric layer 101. In this embodiment, the boundary of the first gap 211 is larger than the boundary of the first electrode 201, so that the bottom surface of the piezoelectric layer 202 at the periphery of the edge of the first electrode 201 is also exposed in the first gap 211. The piezoelectric layer 202 is a horizontally complete membrane layer that extends to the surface above the convex region of the first dielectric layer 101 on all sides. The edge of the first electrode 201 is completely exposed in the first gap 211, so that the edge of the first electrode 201 forms a reflective interface with the air, causing an acoustic impedance mismatch, suppressing shear wave leakage, and thereby improving the quality factor (Q value) of the resonator.

[0053] The second dielectric layer 102 is located above the first dielectric layer 101. The material of the second dielectric layer 102 may include, but is not limited to, one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc. The second dielectric layer may be a single-layer structure or a stacked structure. In this embodiment, the lower surface of the second dielectric layer 102 is concave in the middle and convex at the periphery. A second gap 221 is provided between the upper surface of the second electrode 203 and the lower surface of the concave area of the second dielectric layer 102. In this embodiment, the boundary of the second gap 221 is larger than the boundary of the second electrode 203, so that the upper surface of the piezoelectric layer 202 at the periphery of the edge of the second electrode 203 is exposed in the second gap 221. The edge of the second electrode 203 is completely exposed in the second gap 221, so that the edge of the second electrode 203 forms a reflection interface with the air, causing acoustic impedance mismatch, suppressing shear wave leakage, and thereby improving the quality factor (Q value) of the resonator.

[0054] In this embodiment, the recessed area of the second dielectric layer 102 and the second gap 221 are arranged opposite to the recessed area and the second gap 211 of the first dielectric layer 101, and the protruding area of the second dielectric layer 102 is arranged opposite to the protruding area of the first dielectric layer 101. The effective resonance region of the resonator includes the region where the first electrode 201, the piezoelectric layer 202, and the second electrode 203 overlap in a direction perpendicular to the surface of the piezoelectric layer 202. In this embodiment, the boundaries of the projections of the first gap 211 and the second gap 221 in the direction of the piezoelectric layer 202 surround the boundaries of the projections of the effective resonance region in the direction of the piezoelectric layer 202. "Surrounding" means that the boundaries of the effective resonance region are within the first gap 211 and the second gap 221, or the boundaries of the effective resonance region coincide with the boundaries of the first gap and / or the second gap. Figure 1 The illustrated case shows that the boundary of the effective resonance region is within the first gap 211 and the second gap 221. In this embodiment, the boundaries of the projections of the first gap 211 and the second gap 221 in the direction of the piezoelectric layer 202 surround the boundaries of the projections of the first electrode 201 and the second electrode 203 in the direction of the piezoelectric layer 202. The meaning of "surround" is the same as described above.

[0055] In another embodiment, the first electrode is located in the area enclosed by the boundary of the first gap, or the boundaries of the two electrodes coincide with each other; or, the second electrode is located in the area enclosed by the boundary of the second gap, or the boundaries of the two electrodes coincide with each other. Alternatively, the edge of the first electrode 201 extends out of the area where the first gap 211 is located, and the edge of the second electrode 203 is located in the second gap 221; or the edge of the first electrode 201 is located in the first gap 211, and the edge of the second electrode 203 extends out of the second gap 221; of course, it is also possible that part of the edge of the first electrode 201 is in the first gap 211, and the other part of the edge extends out of the first gap 211, or part of the edge of the second electrode 203 is in the second gap 221, and the other part of the edge extends out of the second gap 221. When the edges of the first electrode 201 and the second electrode 203 are both exposed in their respective gaps, the area of acoustic impedance mismatch can be increased, the shear wave leakage can be further suppressed, and the quality factor (Q value) of the resonator can be improved.

[0056] In this embodiment, the piezoelectric layer 202 includes a resonant portion 2021 and a lap portion 2022 located on the periphery of the resonant portion, the resonant portion 2021 is located in the effective resonant region, and the lap portion 2022 is located outside the effective resonant region. Specifically, in this embodiment, the piezoelectric layer 202 is a complete film layer, and the resonant portion 2021 and the lap portion 2022 are an integral structure. The first gap 211 and the second gap 221 are isolated from each other by the piezoelectric layer 202. In another embodiment, the first gap and the second gap can be connected through a plurality of through holes distributed in the ineffective region, for example, the through holes penetrate the piezoelectric layer in the ineffective region. Or the first gap and the second gap are connected through an annular through hole surrounding the effective region (the annular through hole penetrates the piezoelectric layer), in which case the inner wall of the annular through hole can constitute the boundary of the effective resonant region, and the inner wall of the annular through hole can also be located outside the boundary of the effective resonant region. In another embodiment, a film layer is provided between the first gap and the second gap in the ineffective region, and the film layer is a piezoelectric layer or a film layer of a material different from that of the piezoelectric layer; or, the piezoelectric layer is only located in the effective resonant region.

[0057] A first conductive protrusion 301 is provided on the lower surface of the first electrode 201. The first conductive protrusion 301 can be single or multiple columnar. In this embodiment, the first conductive protrusion 301 is arranged at the edge of the effective resonance zone, and its projection in the direction of the surface of the piezoelectric layer 202 is a ring, wherein the ring includes an intermittent or closed ring. The shape of the ring can be circular, elliptical, polygonal, or an irregular shape composed of arcs and straight edges. A closed ring means that the first conductive protrusion 301 is continuous, and an open ring means that the first conductive protrusion 301 is discontinuous. The area where the first conductive protrusion 301 is located forms an acoustic impedance mismatch with the effective resonance zone, thereby being able to reflect the outwardly propagating lateral sound waves back into the effective resonance zone to suppress the leakage of lateral clutter, reduce energy loss, and improve the quality factor (Q value) of the resonator. When the projection of the first conductive protrusion 301 on the surface of the piezoelectric layer 302 is a closed ring, it is more conducive to preventing lateral leakage of sound waves.

[0058] The other end of the first conductive protrusion 301 is connected to the first electrode lead portion 303. In this embodiment, the first electrode lead portion 303 is buried in the first dielectric layer 101. In other embodiments, the first electrode lead portion 303 can also be located on the upper surface of the recessed area of the first dielectric layer 101. Figure 1 As can be seen in the figure, the first electrode lead portion 303 is led outward from the side where the effective resonance region is located. The first electrode lead portion 303 can serve as a signal input terminal to introduce an electrical signal into the first electrode 201 of the effective resonance region, or as a signal output terminal to output the electrical signal on the first electrode 201.

[0059] A second conductive protrusion 302 is provided on the upper surface of the second electrode 203. The second conductive protrusion 302 can be single or multiple columnar. In this embodiment, the second conductive protrusion 302 is arranged at the edge of the effective resonance zone, and its projection in the direction of the surface of the piezoelectric layer 202 is a ring, wherein the ring includes an intermittent or closed ring. The shape of the ring can be circular, elliptical, polygonal, or an irregular shape composed of arcs and straight edges. A closed ring means that the second conductive protrusion 302 is continuous, and an open ring means that the second conductive protrusion 302 is discontinuous. The area where the second conductive protrusion 302 is located forms an acoustic impedance mismatch with the effective resonance zone, thereby being able to reflect the outwardly propagating lateral sound waves back into the effective resonance zone to suppress the leakage of lateral clutter, reduce energy loss, and improve the quality factor (Q value) of the resonator. When the projection of the second conductive protrusion 302 on the surface of the piezoelectric layer 302 is a closed ring, it is more conducive to preventing lateral leakage of sound waves.

[0060] The other end of the second conductive protrusion 302 is connected to the second electrode lead portion 304. In this embodiment, the second electrode lead portion 304 is buried in the second dielectric layer 102. In other embodiments, the second electrode lead portion 304 can also be located on the lower surface of the recessed area of the second dielectric layer 101. Figure 1 As can be seen in the figure, the second electrode lead portion 304 extends outward from the side where the effective resonance region is located. The second electrode lead portion 304 can serve as a signal input terminal to introduce an electrical signal into the second electrode 203 of the effective resonance region, or as a signal output terminal to output the electrical signal on the second electrode 203. When the first electrode lead portion 303 serves as a signal input terminal, the second electrode lead portion 304 serves as a signal output terminal, and vice versa.

[0061] In this embodiment, the projections of the first conductive protrusion 301 and the second conductive protrusion 302 in the direction of the piezoelectric layer 202 at least partially overlap. The at least partial overlap includes: 1. The projection shapes of the first conductive protrusion 301 and the second conductive protrusion 302 are consistent, and the two completely overlap. 2. The projection area of one of the first conductive protrusion 301 and the second conductive protrusion 302 is larger than the area of the other projection, and the projection with the larger area covers the projection with the smaller area. 3. The shape trends of the two projections are roughly the same, and the overlapping parts of the two are continuous, or only a part of the area of one projection and the other projection has an overlapping part. This setting makes the acoustic impedance mismatch effect of the two conductive protrusions superimposed, effectively prevents the lateral leakage of sound waves, and further improves the quality factor of the resonator.

[0062] In another embodiment, the projection of one of the conductive protrusions on the surface of the piezoelectric layer is located outside the projection of the other conductive protrusion on the surface of the piezoelectric layer. For example, when both conductive protrusions are annular, one of the annular shapes surrounds the other. In this case, when a transverse acoustic wave propagates to the region where one of the conductive protrusions is located, a single acoustic wave reflection occurs. When the remaining transverse acoustic wave continues to propagate to the region where the other conductive protrusion is located, another acoustic wave reflection occurs. These two reflections effectively prevent leakage of the transverse acoustic wave, thereby improving the quality factor of the resonator.

[0063] In this embodiment, the projections of the first electrode lead portion 303 and the second electrode lead portion 304 in the direction of the piezoelectric layer 202 are staggered to avoid high-frequency coupling caused by potential floating and prevent parasitic capacitance effects.

[0064] In another embodiment, the projections of the first conductive protrusion 301 and the second conductive protrusion 302 on the surface of the piezoelectric layer together form a ring. It should be understood that when the projections of the first conductive protrusion 40a and / or the second protrusion 40b on the surface of the piezoelectric layer form a closed shape, it is more conducive to preventing lateral leakage of sound waves.

[0065] The first conductive protrusion 301 or the second conductive protrusion 302 is made of a conductive material, such as a low resistivity material such as gold, silver, tungsten, platinum, aluminum, copper, etc.

[0066] The material of the first electrode lead portion 303 or the second electrode lead portion 304 may refer to the material of the first conductive protrusion 301 or the second conductive protrusion 302 . The material of the conductive protrusion may be the same as or different from the material of the electrode lead portion.

[0067] Example 2

[0068] Embodiment 2 of the present invention provides a thin film bulk acoustic resonator. Figure 2 FIG2 is a structural diagram of a thin film bulk acoustic wave resonator according to embodiment 2 of the present invention. The difference between this embodiment and embodiment 1 is that in this embodiment, the resonant portion 2021 and the overlapping portion 2022 of the piezoelectric layer 202 are separated from each other. Figure 2 , the specific structure is as follows:

[0069] The resonant portion 2021 and the overlapping portion 2022 of the piezoelectric layer 202 are separated from each other, the edge of the first electrode 201 is exposed in the first gap 211, and the edge of the second electrode 203 is exposed in the second gap 221. The first gap 211 and the second gap 221 are interconnected to form an integral cavity. The resonant portion 2021 is located inside the cavity, and the overlapping portion 2022 is located outside the cavity. The overlapping portion 2022 and the resonant portion 2021 are completely separated, so that the outer periphery of the resonant portion 2021 is exposed in the cavity. Figure 2 As shown in , the edge of the resonant portion 2021 of the piezoelectric layer coincides with the edges of the first electrode 201 and the second electrode 203, forming the edge of the effective resonant region. At this time, the resonant portion 2021 is entirely located in the effective resonant region. In another embodiment, the resonant portion 2021 and the overlapping portion 2022 have both interconnected parts and separated parts. The edge of the resonant portion 2021 exposed in the cavity forms a reflective interface with the air, causing an acoustic impedance mismatch, suppressing shear wave leakage, and thereby improving the quality factor (Q value) of the resonator. When the resonant portion 2021 is completely separated from the overlapping portion 2022, so that the edge of the resonant portion 2021 is completely exposed in the cavity, the effect of preventing shear wave leakage is best. When the resonant portion 2021 and the overlapping portion 2022 have both interconnected parts and separated parts, the structural strength of the resonator can be improved. The other structural parts of this embodiment refer to Example 1 and are not repeated here.

[0070] Example 3

[0071] Embodiment 3 of the present invention provides a thin film bulk acoustic resonator, Figure 3FIG3 is a schematic diagram of the structure of a thin film bulk acoustic resonator according to Example 3 of the present invention. The difference between this embodiment and Example 1 is that:

[0072] The first conductive protrusion 301 is entirely located at the edge of the first gap 211, contacting the outer first dielectric layer 101. A portion of the second conductive protrusion 302 is located at the edge of the second gap 221, contacting the second dielectric layer 102, and a portion is located within the second gap 221, with a distance from the boundary of the second gap 221. It should be understood that the conductive protrusion is located at the boundary of the effective resonant region, i.e., at least a portion of the boundary of the effective resonant region overlaps with a portion of the boundary of the gap. The positional relationship between the first conductive protrusion and the first gap, and the positional relationship between the second conductive protrusion and the second gap, can be various, such as: the first conductive protrusion is located at the boundary of the first gap, or the first conductive protrusion is spaced apart from the boundary of the first gap, or a portion of the first conductive protrusion is located at the boundary of the first gap, while another portion of the first conductive protrusion is spaced apart from the boundary of the first gap; and / or the second conductive protrusion is located at the boundary of the second gap, or the second conductive protrusion is spaced apart from the boundary of the second gap, or a portion of the second conductive protrusion is located at the boundary of the second gap, while another portion of the second conductive protrusion is spaced apart from the boundary of the second gap. That is, part or all of the first conductive protrusions 301 may be located at the edge of the first gap 211 , and part or all of the second conductive protrusions 302 may be located at the edge of the second gap 221 .

[0073] In the above embodiments 1 to 3, the first electrodes are all located on the carrier substrate and below the second electrodes. However, in these embodiments, the second electrodes may also be all located on the carrier substrate and below the first electrodes.

[0074] The present invention forms The method for manufacturing a thin film bulk acoustic resonator includes:

[0075] Step S1, forming a first structure, wherein the first structure includes: a first electrode, a first sacrificial layer at least covering the first electrode, and a dielectric layer surrounding the first sacrificial layer at least on a side surface of the first sacrificial layer;

[0076] Step S2, forming a first conductive protrusion, which penetrates the first sacrificial layer and has one end connected to the first electrode;

[0077] Step S3, forming a first electrode lead portion, one end of which is connected to the other end of the first conductive protrusion, and the other end of which extends out of the effective resonance region;

[0078] Step S4, forming a piezoelectric layer;

[0079] Step S5, forming a second structure, wherein the second structure includes: a second electrode, a second sacrificial layer at least covering the second electrode, and a dielectric layer surrounding the second sacrificial layer at least on a side surface of the second sacrificial layer;

[0080] Step S6, forming a second conductive protrusion, which penetrates the second sacrificial layer and has one end connected to the second electrode;

[0081] Step S7, forming a second electrode lead portion, one end of which is connected to the other end of the second conductive protrusion, and the other end of which extends out of the effective resonance region;

[0082] Step S8 , removing the first sacrificial layer and the second sacrificial layer to form the first gap and the second gap.

[0083] The above steps can be performed in sequence or in any order.

[0084] In one of the schemes: a temporary substrate is provided; steps S1-S3 are sequentially performed on the temporary substrate; after step S3, a carrier substrate is bonded to the side where the first electrode lead-out portion is located, and the temporary substrate is removed; then, steps S5-S7 are sequentially performed on the carrier substrate.

[0085] The step S4 of forming the piezoelectric layer can be performed 1) before performing step S1, or 2) after performing step S3 and before performing step S4. The piezoelectric layer can be a film layer with both the effective resonance region and the ineffective region distributed, or can be a patterned film layer located only in the effective resonance region. For details, please refer to the detailed description in Example 4 below.

[0086] In another embodiment, a carrier substrate is provided; step S3 is first performed on the carrier substrate to form the first electrode lead-out portion, and then steps S1 and S3 are performed. The order of forming the structures between steps S1 and S3 may be: forming the first sacrificial layer, the first dielectric layer, the first conductive protrusion, and then the first electrode. Thereafter, steps S5-S7 are performed to form the second structure, the second conductive protrusion, and the second electrode lead-out portion.

[0087] The step S4 of forming the piezoelectric layer may include: 1) forming the piezoelectric layer during the process of forming the first electrode in step S1, for example, sequentially forming the first electrode layer, the piezoelectric layer, and the second electrode layer, and then patterning the three-layer structure to form the first electrode, the piezoelectric layer, and the second electrode located in the effective resonance region; 2) alternatively, after performing step S1, forming a flat layer around the first electrode, wherein the surface of the flat layer is flush with the surface of the first electrode, and then forming the piezoelectric layer, wherein the piezoelectric layer is located in the effective resonance region and the ineffective resonance region. For details, please refer to the detailed description in the following embodiment 6.

[0088] In another scheme: a temporary substrate is provided; steps S1, S5, S6, and S7 are sequentially performed on the temporary substrate to form the first structure, the second structure, the second conductive protrusion, and the second electrode lead-out portion; a carrier substrate is bonded to the side where the second electrode lead-out portion is located, and then the temporary substrate is removed; after bonding the carrier substrate, steps S2 and S3 are sequentially performed to form the first conductive protrusion and the first electrode lead-out portion.

[0089] The step S4 of forming the piezoelectric layer can be performed after 1) performing step S1, with the piezoelectric layer being distributed evenly in the inactive region and the active region, or only in the active region. Alternatively, the step S4 can be performed after 2) performing step S3 and before performing step S4, with the piezoelectric layer being distributed evenly in the active resonance region and the inactive region, or only in the active resonance region after patterning. For details, please refer to the detailed description in Example 5 below.

[0090] The following describes various embodiments in detail with reference to the accompanying drawings:

[0091] Example 4

[0092] Figures 4 to 13 This is a schematic structural diagram corresponding to different steps in a method for manufacturing a thin film bulk acoustic resonator according to embodiment 4 of the present invention, which will be referred to below. Figures 4 to 13 This embodiment will be described in detail.

[0093] refer to Figure 4-Figure 9 , providing a temporary substrate 200, and forming a first structure, a first conductive protrusion, and a first electrode lead-out portion on the temporary substrate.

[0094] Specifically, refer to Figure 4 , a second electrode layer 203 ′, a piezoelectric layer 202 and a first electrode layer 201 ′ are formed on the temporary substrate 200 .

[0095] The material of the temporary substrate 200 can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon silicon (Si), carbon germanium silicon (SiGe), indium arsenide (Ins), gallium arsenide (Gs), indium phosphide (InP) or other III / V compound semiconductors.

[0096] In addition, in order to facilitate the subsequent peeling of the temporary substrate 200, an isolation layer can be formed on the temporary substrate 200. The isolation layer is located between the temporary substrate 200 and the second electrode layer 203'. In the subsequent peeling process, the temporary substrate 200 can be separated from the subsequently formed second electrode layer 203' by etching the isolation layer, which helps to quickly peel off the temporary substrate and improve the process efficiency. If the isolation layer is not formed between the temporary substrate 200 and the second electrode layer 203', the temporary substrate can be removed by mechanical grinding or other methods. The material of the isolation layer includes but is not limited to at least one of silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3) and aluminum nitride (AlN). The isolation layer can be formed by chemical vapor deposition, magnetron sputtering or evaporation.

[0097] First, a second electrode layer 203' is deposited on a temporary substrate 200, then a piezoelectric layer 202 is deposited on the second electrode layer 203', and finally, a first electrode layer 201' is deposited on the piezoelectric layer 202. Forming the piezoelectric layer 202 on the flat second electrode layer 203' can provide the piezoelectric layer 202 with a better lattice orientation, improve the piezoelectric properties of the piezoelectric layer 202, and thus enhance the overall performance of the resonator.

[0098] The materials for the piezoelectric layer 202 refer to the description of the structural embodiment above. The piezoelectric layer 202 can be deposited using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition. The materials for the first electrode layer 201' and the second electrode layer 203' refer to the description of the first and second electrode materials in the structural embodiment above. The first electrode layer 201' or the second electrode layer 203' can be formed using physical vapor deposition methods such as magnetron sputtering and evaporation, or chemical vapor deposition methods.

[0099] refer to Figure 5 After forming the first electrode layer 201', the first electrode layer 201' is patterned to form the first electrode 201. The method for patterning the first electrode layer 201' can be to etch the first electrode layer 201' using an etching process. The etching process can be a wet etching process or a dry etching process, with a dry etching process being preferably used. Dry etching includes but is not limited to reactive ion etching (RIE), ion beam etching, plasma etching, or laser cutting. In this embodiment, the boundary of the first electrode 201 is located within the first gap formed subsequently, and the shape of the first electrode 201 is an irregular polygon.

[0100] refer to Figure 6, forming a first sacrificial layer material, covering the first electrode 201 and the piezoelectric layer 202. The first sacrificial material is patterned to form a first sacrificial layer 210, and the first sacrificial layer 210 at least covers the first electrode 201. At least covering means that the boundary of the first sacrificial layer 210 coincides with the boundary of the first electrode or the boundary of the first sacrificial layer is located outside the boundary of the first electrode. In this embodiment, the first sacrificial layer also covers the piezoelectric layer 202 on the periphery of the first electrode 201. The first sacrificial layer 210 forms a first gap after being released in a subsequent process. The area of the first sacrificial layer 210 determines the area of the first gap, and the height of the first sacrificial layer 210 determines the height of the first gap. The first sacrificial layer material includes phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist, and can be formed by chemical vapor deposition.

[0101] refer to Figure 7 , forming a dielectric layer 101A (hereinafter referred to as dielectric layer 101A) that surrounds the first sacrificial layer at least on its sides, covering the first sacrificial layer 210 and the piezoelectric layer 202 surrounding the first sacrificial layer 210. The dielectric layer 101A can be made of one or a combination of silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3), and aluminum nitride, and can be formed by physical vapor deposition or chemical vapor deposition. The surface of the dielectric layer 101A can also be flush with the surface of the sacrificial layer.

[0102] refer to Figure 8 , a first conductive protrusion 301 is formed on the surface of the first electrode 201. Specifically, a first through hole is formed, penetrating the first sacrificial layer 210 and the dielectric layer 101A above the first sacrificial layer 210, and a conductive material is formed in the first through hole to form the first conductive protrusion 301. The first through hole can be formed by an etching process or a punching process. The conductive material can be formed in the first through hole by deposition or electroplating, and the conductive material includes: gold, silver, tungsten, platinum, aluminum, copper and other low-resistivity materials. In this embodiment, the first conductive protrusion 301 is formed at the edge of the effective resonance region. Its position, structure and function refer to the relevant description of the structural embodiment above.

[0103] refer to Figure 9A release hole 212 is formed in the dielectric layer 101A above the first sacrificial layer, and the first sacrificial layer is removed through the release hole 212. To completely release the first sacrificial layer, multiple release holes can be provided, distributed in different areas above the first sacrificial layer. A corresponding removal method is employed based on the selected material of the first sacrificial layer. For example, when the first sacrificial layer is made of polyimide or photoresist, it is removed by ashing. Specifically, at a temperature of 250 degrees Celsius, oxygen passing through the release hole 212 chemically reacts with the first sacrificial layer material, generating gaseous substances that evaporate. When the first sacrificial layer is made of low-temperature silicon dioxide, it is removed by reacting hydrofluoric acid with the low-temperature silicon dioxide. After the first sacrificial layer is removed, a first gap 211 is formed between the surface of the first electrode 201 and the dielectric layer 101A.

[0104] After removing the first sacrificial layer, forming the first electrode lead-out portion includes: forming a first passivation layer; etching the first passivation layer to form a first groove; forming a first conductive layer in the first groove to serve as the first electrode lead-out portion; or forming a first conductive layer and patterning the first conductive layer to form the first electrode lead-out portion; forming a first passivation layer to cover the first electrode lead-out portion; the first dielectric layer includes the first passivation layer. When the first passivation layer is formed before the first electrode lead-out portion, the surfaces of the first passivation layer and the first electrode lead-out portion are flush, and a dielectric layer can be formed on the flush surface to facilitate subsequent bonding to a carrier substrate. When the first electrode lead-out portion is formed before the first passivation layer, the surfaces of the first passivation layer and the first electrode lead-out portion are flush or cover the first electrode lead-out portion. If they are flush, a dielectric layer is formed on the flush surface to facilitate subsequent bonding to a carrier substrate.

[0105] The first electrode lead-out portion 303 extends beyond the area where the first gap 211 is located. In this embodiment, the first electrode lead-out portion 303 is in a strip shape, extending outward from the side where the first gap 211 is located. In another embodiment, the first electrode lead-out portion 303 is in a planar shape. It should be understood that the function of the first electrode lead-out portion 303 is to connect external signals and provide an electrical connection. Its shape and area can be flexibly selected according to the specific situation.

[0106] refer to Figure 10 In this embodiment, a carrier substrate 100 is formed on the upper surface of the first passivation layer 101B. The carrier substrate 100 can be bonded to the first passivation layer 101B by bonding. The bonding layer material includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, or ethyl silicate. The first dielectric layer in which the first electrode lead portion 303 is embedded includes: a dielectric layer 101A that encloses the first gap 211 and a first passivation layer 101B.

[0107] refer to Figure 11-14, removing the temporary substrate. Forming the second structure, the second conductive protrusion, and the second electrode lead portion on the carrier substrate in sequence.

[0108] refer to Figure 11 , remove the temporary substrate. When an isolation layer is formed on the temporary substrate, the temporary substrate can be removed by etching the isolation layer. If no isolation layer is formed between the temporary substrate and the second electrode layer 203', the temporary substrate can be removed by mechanical grinding or other methods.

[0109] refer to Figure 12 The second electrode layer is patterned to form a second electrode 203. In this embodiment, the second electrode 203 is symmetrically arranged with the first electrode 201 in shape and size. In other embodiments, the shape of the second electrode and the shape of the first electrode may be different. In an optional embodiment, the edge of the second electrode 203 is located above the area enclosed by the first gap 211. In this embodiment, the edge of the second electrode 203 is also located within the area enclosed by the second gap formed in a subsequent process.

[0110] refer to Figure 13 , forming a second sacrificial layer material, covering the second electrode 203 and the piezoelectric layer 202. The second sacrificial material is patterned to form a second sacrificial layer 220. The first sacrificial layer 220 at least covers the second electrode 203. At least covering means that the boundary of the second sacrificial layer 210 coincides with the boundary of the second electrode 203 or the boundary of the second sacrificial layer 210 is located outside the boundary of the second electrode 203. In this embodiment, the second sacrificial layer 220 also covers the piezoelectric layer 202 outside the second electrode 203. The second sacrificial layer 220 is released in a subsequent process to form a second gap. The materials and formation methods of the second sacrificial layer refer to those of the first sacrificial layer.

[0111] After forming the second sacrificial layer 220, a dielectric layer 102A (hereinafter referred to as dielectric layer 102A) is formed, surrounding the second sacrificial layer at least on its sides, covering the second sacrificial layer 220 and the piezoelectric layer 202 surrounding the second sacrificial layer. The materials and formation methods for dielectric layer 102A refer to those for dielectric layer 101A. The illustrated embodiment shows dielectric layer 102A covering the top surface of second sacrificial layer 220, but the present invention is not limited thereto. Alternatively, dielectric layer 102A may be located only around the second sacrificial layer 220, with no dielectric layer 102A present on the top surface.

[0112] After dielectric layer 102A is formed, a second conductive protrusion 302 is formed, one end of which is connected to the second electrode and the other end is exposed from the film layer above the second electrode. The materials and formation methods of second conductive protrusion 302 are similar to those of the first conductive protrusion and will not be repeated here. The position, structure, and function of second conductive protrusion 302, as well as the positional relationship between the second conductive protrusion and the first conductive protrusion, are described in the previous description of the structural embodiment.

[0113] refer to Figure 14 A release hole is formed in the dielectric layer 102A above the second sacrificial layer, and the second sacrificial layer is removed through the release hole to form a second gap 221 between the upper surface of the second electrode 203 and the first second dielectric layer 102A.

[0114] After removing the second sacrificial layer, a second electrode lead-out portion 304 is formed, and the second electrode lead-out portion 304 is electrically connected to the second conductive protrusion 302. The second electrode lead-out portion 304 includes: forming a second passivation layer 102B; etching the second passivation layer to form a second groove; forming a second conductive layer in the second groove as the second electrode lead-out portion; or forming a second conductive layer, patterning the second conductive layer to form the second electrode lead-out portion; forming a second passivation layer to cover the second electrode lead-out portion; the second dielectric layer 102 includes the second passivation layer 102B and the dielectric layer 102A surrounding the second gap 221. When the second passivation layer 102B is formed first and then the second electrode lead-out portion is formed, the second passivation layer and the surface of the second electrode lead-out portion are flush, and then a dielectric layer can be formed on the flush surface to protect the second electrode lead-out portion; when the second electrode lead-out portion is formed first and then the second passivation layer is formed, the second passivation layer and the surface of the second electrode lead-out portion are flush or cover the second electrode lead-out portion ( Figure 14 If it is not covered, a dielectric layer covering the second electrode lead-out portion needs to be formed to protect the second electrode lead-out portion.

[0115] The material of the second electrode lead portion 304 is similar to that of the first electrode lead portion 303. The second electrode lead portion 304 extends beyond the region where the second gap 221 is located. In this embodiment, the second electrode lead portion 304 is strip-shaped and extends outward from the side where the second gap 211 is located. Outside the effective resonance region, the projections of the first electrode lead portion 303 and the second electrode lead portion 304 in the direction of the piezoelectric layer 202 are staggered.

[0116] In the present invention, after forming the second electrode lead-out portion, a release hole may be formed to remove the second sacrificial layer.

[0117] Modification 1 of Example 4:

[0118] In Example 4, a second electrode layer, a piezoelectric layer, and a first electrode layer are sequentially formed on a temporary substrate. The first electrode layer is then patterned to form the first electrode. After forming the first structure, the temporary substrate is removed by bonding to a carrier substrate, and the second electrode layer is patterned to form a second electrode. The second structure, a second electrode lead, and a second conductive protrusion are then formed. When etching to form the first or second electrode, the piezoelectric layer is never etched, preserving its integrity and maintaining a piezoelectric layer distributed across both the active and inactive regions. The first and second gaps are separated by the piezoelectric layer. Therefore, the first sacrificial layer and the second sacrificial layer are disconnected and need to be removed separately.

[0119] In the first variation, the piezoelectric layer can be patterned after forming the first electrode or the second electrode to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the effective resonant region. For the advantages of this approach, please refer to the corresponding sections of the structural embodiment.

[0120] Correspondingly, in this variation example 1, after the second sacrificial layer is formed, the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer. At this time, the first sacrificial layer and the second sacrificial layer are interconnected, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.

[0121] Modification 2 of Example 4

[0122] After sequentially forming a second electrode layer, a piezoelectric layer, and a first electrode layer on a temporary substrate, the first electrode layer, piezoelectric layer, and second electrode layer are patterned, and portions of the first electrode layer, piezoelectric layer, and second electrode layer located in the inactive area are removed to form the first electrode, second electrode, and piezoelectric layer. Next, a first sacrificial layer and a first dielectric layer are formed, with the first sacrificial layer covering the top and side surfaces of the first electrode, second electrode, and piezoelectric layer. Next, referring to the method of Example 4, a first conductive protrusion and a first electrode lead-out portion are formed. Finally, a carrier substrate is bonded and the temporary substrate is removed to form a second sacrificial layer, a second conductive protrusion, a second electrode lead-out portion, and the like.

[0123] The structure formed by the second modification can refer to Figure 29 .

[0124] In the second variation, the first sacrificial layer and the second sacrificial layer are connected to each other, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.

[0125] Modification 3 of Example 4

[0126] In this third variation, a piezoelectric layer and a first electrode layer are sequentially formed on a temporary substrate; the first electrode layer is patterned to form the first electrode. Subsequently, referring to the method of Example 4, a first sacrificial layer and a first dielectric layer are formed, with the first sacrificial layer covering the top and side surfaces of the first electrode. A first conductive protrusion and a first electrode lead portion are then formed. Continuing with the method of the embodiment, the temporary substrate is removed, the carrier substrate is bonded, and after flipping, a second electrode layer is formed. The second electrode layer is patterned to form the second electrode. Subsequently, referring to the method of Example 4, a second conductive protrusion, a second electrode lead portion, a second sacrificial layer, a second dielectric layer, and so on are formed.

[0127] In this third variation, the piezoelectric layer can be maintained distributed in both the ineffective region and the effective resonance region. In this case, since the first sacrificial layer and the second sacrificial layer are separated from each other, the first sacrificial layer and the second sacrificial layer need to be removed separately.

[0128] In this third variation, the piezoelectric layer may be patterned after forming the first electrode or the second electrode to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the effective resonant region. In this case, after forming the second sacrificial layer, the first sacrificial layer remains, and the second sacrificial layer also fills the periphery of the patterned piezoelectric layer. In this case, the first and second sacrificial layers are interconnected, and the first and second sacrificial layers can be removed simultaneously.

[0129] Modification 4 of Example 4

[0130] In Variation 4, the second electrode layer, piezoelectric layer, and first electrode layer are not sequentially formed on the temporary substrate. In this embodiment, a first electrode and a planar layer are formed on the temporary substrate, with the surfaces of the first electrode and the planar layer flush. Subsequently, the first sacrificial layer, first dielectric layer, first conductive protrusion, and first electrode lead-out portion are formed using the method of Embodiment 4.

[0131] Then, a carrier substrate is bonded, the temporary substrate is removed, and a piezoelectric layer is formed on the flush surface of the first electrode and the flat layer on the carrier substrate.

[0132] Next, referring to the method of Example 4, a second electrode layer is formed on the piezoelectric layer; the second electrode layer is patterned to form a second electrode; and a second dielectric layer, a second sacrificial layer, a second conductive protrusion, and a second electrode lead portion are formed.

[0133] In this fourth variation, the piezoelectric layer may be located in the effective resonance region and the ineffective region. In this case, the first sacrificial layer and the second sacrificial layer are separated from each other and need to be removed separately.

[0134] In this fourth variation, the piezoelectric layer can also be patterned before or after patterning the second electrode layer to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the effective resonant region. In this case, after forming the second sacrificial layer, the first sacrificial layer remains, and the second sacrificial layer also fills the periphery of the patterned piezoelectric layer. In this case, the first and second sacrificial layers are interconnected, and the first and second sacrificial layers can be removed simultaneously.

[0135] Example 5

[0136] In this embodiment, relative to the carrier substrate, the first electrode is located below the second electrode. In embodiment 4, the first electrode is located above the second electrode.

[0137] Embodiment 5 of the present invention provides a method for manufacturing a thin film bulk acoustic resonator. Figures 15 to 21 This is a schematic structural diagram corresponding to different steps in a method for manufacturing a thin film bulk acoustic resonator according to embodiment 5 of the present invention, which will be referred to below. Figures 15 to 21 This embodiment will be described in detail.

[0138] refer to Figure 15 , provide a temporary substrate 200; the material of the temporary substrate 200 can refer to the relevant content of Example 4.

[0139] refer to Figure 15 and Figure 16 The first structure is formed on the temporary substrate 200. This includes: first forming a first sacrificial layer 210 and a dielectric layer 101A surrounding the first sacrificial layer, and then forming a first electrode 201. The first sacrificial layer only covers the top surface of the first electrode (the surface close to the temporary substrate) or covers the top surface and side surfaces of the first electrode.

[0140] The dielectric layer 101A covers the side surfaces of the first sacrificial layer and the side surfaces of the first electrode, or covers the side surfaces, the top surface of the first sacrificial layer and the side surfaces of the first electrode.

[0141] The specific method of forming the first electrode includes: referring to Figure 16 , the first sacrificial layer is etched to form a groove, and a conductive material is filled in the groove as a first electrode. If the conductive material is formed outside the groove, the conductive material outside the groove needs to be removed, which can be removed by chemical mechanical grinding or etching.

[0142] A modified method of forming the first electrode may also be: forming a first electrode layer on the surface of the first sacrificial layer 210 and the dielectric layer 101A, and then patterning the first electrode layer to form the first electrode 201. In this case, the first electrode is located on the first sacrificial layer rather than embedded in the first sacrificial layer.

[0143] The method for forming the first sacrificial layer 210 and the dielectric layer 101A may refer to Example 4.

[0144] refer to Figure 17 After forming the first structure, a piezoelectric layer 202 is formed on the temporary substrate. The specific forming method can refer to the relevant content of forming the piezoelectric layer in Example 4.

[0145] refer to Figure 17 and Figure 18 After forming the piezoelectric layer, a second structure is formed on the temporary substrate. The specific method includes: forming a second electrode layer, patterning the second electrode layer to form a second electrode 203; and then forming a second sacrificial layer 220 and a dielectric layer 102A surrounding the second sacrificial layer 220. The relevant content of Example 4 can be cited here.

[0146] refer to Figure 19 and Figure 20 After forming the second structure, a second conductive protrusion 302 and a second electrode lead-out portion 304 are formed on the temporary substrate 200. The first sacrificial layer is then removed. During the formation of the second electrode lead-out portion 304, a second passivation layer 102B is also formed. The relevant content of Example 4 is incorporated herein by reference. The second dielectric layer 102 includes a dielectric layer 102A and a second passivation layer 102B.

[0147] refer to Figure 21 The carrier substrate 100 is bonded to the side where the second electrode lead portion 304 is located, and the temporary substrate is then removed. After bonding the carrier substrate, the first conductive protrusion 301 and the first electrode lead portion 303 are sequentially formed. During the formation of the first electrode lead portion 303, the first passivation layer 101B is also formed. The relevant content of Example 4 can be referenced here. The first dielectric layer 101 includes a dielectric layer 101A and a second passivation layer 101B.

[0148] The method for removing the first sacrificial layer and the second sacrificial layer in the fourth embodiment can be referred to in the fifth embodiment.

[0149] Modification 1 of Example 5

[0150] In Example 5, after the first electrode is formed, the piezoelectric layer is formed, and then the second electrode is formed. The first electrode layer, the piezoelectric layer, and the second electrode layer are not formed in this order. The piezoelectric layer is not etched during the sequential steps, preserving the integrity of the piezoelectric layer. The piezoelectric layer is distributed in both the active and inactive areas. The first gap and the second gap are separated by the piezoelectric layer. Therefore, the first sacrificial layer and the second sacrificial layer are not connected to each other and need to be removed separately.

[0151] In the first variation, after forming the second electrode or the piezoelectric layer, the piezoelectric layer can be patterned to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the effective resonant region. For the advantages of this scenario, please refer to the corresponding section of the structural embodiment.

[0152] Correspondingly, in this variation example 1, after the second sacrificial layer is formed, the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer. At this time, the first sacrificial layer and the second sacrificial layer are interconnected, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.

[0153] Modification 2 of Example 5

[0154] After forming a first sacrificial layer and a first dielectric layer on a temporary substrate, a second electrode layer, a piezoelectric layer, and a first electrode layer are sequentially formed on the temporary substrate. The first electrode layer, the piezoelectric layer, and the second electrode layer are then patterned, and portions of the first electrode layer, the piezoelectric layer, and the second electrode layer located in the inactive area are removed to form the first electrode, the second electrode, and the piezoelectric layer. Next, a second sacrificial layer and a second dielectric layer are formed, with the second sacrificial layer covering the top and side surfaces of the first electrode, the second electrode, and the piezoelectric layer. Next, referring to the method of Example 4, a second conductive protrusion and a second electrode lead-out portion are formed. Finally, a carrier substrate is bonded, and the temporary substrate, the first conductive protrusion, and the first electrode lead-out portion are removed.

[0155] The structure formed by the second modification can refer to Figure 29 .

[0156] In the second variation, the first sacrificial layer and the second sacrificial layer are connected to each other, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.

[0157] Modification 3 of Example 5

[0158] In the third variation, after forming the first dielectric layer and the first sacrificial layer on the temporary substrate, a first electrode and a planar layer are formed on the temporary substrate, with the first electrode and the planar layer being flush with each other. Subsequently, the piezoelectric layer is formed using the method described in Example 5. The steps and methods for forming the subsequent structures are similar to those described in Example 5.

[0159] In this third variation, the piezoelectric layer may be located in the effective resonance region and the ineffective region. In this case, the first sacrificial layer and the second sacrificial layer are separated from each other and need to be removed separately.

[0160] In this third variation, the piezoelectric layer can also be patterned before or after patterning the second electrode layer to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the effective resonant region. In this case, after forming the second sacrificial layer, the first sacrificial layer remains, and the second sacrificial layer also fills the periphery of the patterned piezoelectric layer. In this case, the first and second sacrificial layers are interconnected, and the first and second sacrificial layers can be removed simultaneously.

[0161] Example 6

[0162] Embodiment 6 of the present invention provides a method for manufacturing a thin film bulk acoustic resonator. Figures 22 to 30 This is a schematic structural diagram corresponding to different steps in a method for manufacturing a thin film bulk acoustic resonator according to embodiment 6 of the present invention, which will be referred to below. Figures 22 to 30 This embodiment will be described in detail.

[0163] refer to Figure 22 A carrier substrate 100 is provided, and a first electrode lead portion 303 is formed on the carrier substrate 100. The material of the first electrode lead portion 303 is similar to that of Example 1. A first conductive layer can be formed by physical vapor deposition, and then the first conductive layer is patterned to form the first electrode lead portion 303. The relevant content of Example 4 can be cited here.

[0164] refer to Figure 23 and Figure 24 , forming a first dielectric layer 101 and a first sacrificial layer 210. Specifically:

[0165] A first dielectric layer 101 is formed around and above the first electrode lead-out portion 303, and the first dielectric layer 101 is etched to form a first gap 211, so that one end of the first electrode lead-out portion 303 is located within the first gap 211 and the other end is located outside the first gap 211. A portion of the first dielectric layer may remain on the upper surface of the first electrode lead-out portion 303, or the first electrode lead-out portion 303 may be exposed at the bottom of the first gap 211.

[0166] refer to Figure 24 A first sacrificial layer 210 is filled in the first gap. The material and formation method of the first sacrificial layer are similar to those of Embodiment 4. The first sacrificial layer 210 is flush with the upper surface of the first dielectric layer 101. Alternatively, the first sacrificial layer can be formed first, followed by the first dielectric layer. The relevant contents of Embodiment 4 are incorporated herein by reference.

[0167] Continue to refer Figure 24 , a first conductive protrusion 210 is formed in the first sacrificial layer, and the lower end of the first conductive protrusion 210 is connected to the first electrode lead portion 303. The relevant contents of the structure, shape, and position of the first conductive protrusion 210 in Example 4 can be cited here. Figure 25 A first electrode layer 201 ′, a piezoelectric layer 202 , and a second electrode layer 203 ′ are sequentially formed on the first sacrificial layer 210 and the first dielectric layer 101 . The materials and formation methods of the three layers are as described in Example 4.

[0168] refer to Figure 26 The second electrode layer 203', the piezoelectric layer 202, and the first electrode layer 201' are etched to form the second electrode 203, the piezoelectric layer 202, and the first electrode 201. In this embodiment, the edges of the three electrodes are all located above the area enclosed by the first sacrificial layer 210, and their boundaries overlap. The boundaries of the three electrodes constitute the boundaries of the effective resonance region, and the first conductive protrusion 301 is located at the boundary of the effective resonance region. The second electrode layer 203', the piezoelectric layer 202, and the first electrode layer 201' are etched simultaneously, saving process time.

[0169] refer to Figure 27 A second sacrificial layer 220 is formed, covering the surface of the second electrode 203 and the second electrode 203, the piezoelectric layer 202, and the periphery 220 of the first electrode 201. A second dielectric layer 102 is formed around the second sacrificial layer 220. The materials and formation methods of the second sacrificial layer 220 and the second dielectric layer 102 are similar to those of Example 4.

[0170] refer to Figure 28 A second conductive protrusion 302 is formed in the second sacrificial layer 220, and a second electrode lead-out portion 304 is formed on the upper surface of the second sacrificial layer 220. One end of the second electrode lead-out portion 304 is located within the boundary of the second sacrificial layer 220, and the other end is located on the second dielectric layer 102 outside the second sacrificial layer 220.

[0171] refer to Figure 29 A dielectric layer is formed on the second sacrificial layer 220 , the second electrode lead portion 304 and the second dielectric layer 102 around the second sacrificial layer 220 to cover the second electrode lead portion 304 .

[0172] refer to Figure 30 The first and second sacrificial layers are removed to form a first gap 211 and a second gap 221. In this embodiment, the first and second sacrificial layers are connected and made of the same material, so they can be removed at once. A release hole can be formed in the second dielectric layer 102 above the second sacrificial layer to allow removal through the release hole.

[0173] Modification 1 of Example 6

[0174] In Example 6, after forming the first electrode lead-out portion, the first structure, and the first conductive protrusion, the first electrode layer, the piezoelectric layer, and the second electrode layer are sequentially deposited, and then the three-layer structure is patterned. The corresponding first sacrificial layer and the second sacrificial layer are connected and can therefore be removed simultaneously.

[0175] In this first variation, after forming the first electrode lead-out portion, the first structure, and the first conductive protrusion, a first electrode and a planar layer are formed, with the first electrode and the planar layer surfaces flush. A piezoelectric layer is then formed on the flush surface. A second electrode layer is then formed on the piezoelectric layer. The second electrode layer is then patterned to form a second electrode. The subsequent formation process steps are the same as in Example 6.

[0176] The difference is that after patterning the second electrode layer, the piezoelectric layer is patterned to remove the piezoelectric layer in the inactive region or to form an air gap around the piezoelectric layer in the active resonance region. When forming the second sacrificial layer, the second sacrificial layer fills the disconnected area around the piezoelectric layer in the active resonance region. Therefore, the first and second sacrificial layers are connected and can be removed simultaneously.

[0177] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A thin film bulk acoustic resonator, characterized in that: include: A stacked first electrode, a piezoelectric layer, and a second electrode, wherein an effective resonance region includes an area where the first electrode, the piezoelectric layer, and the second electrode overlap in a direction perpendicular to a surface of the piezoelectric layer, and an ineffective region is outside the effective resonance region; a first dielectric layer, wherein a first gap is provided between an upper surface of the first dielectric layer and a lower surface of the first electrode; a second dielectric layer, wherein a second gap is provided between a lower surface of the second dielectric layer and an upper surface of the second electrode; a first conductive protrusion, one end of which is disposed on the lower surface of the first electrode and the other end of which is connected to the first electrode lead-out portion; a second conductive protrusion, one end of which is disposed on the upper surface of the second electrode and the other end of which is connected to the second electrode lead portion; The first electrode is located in an area enclosed by a boundary of the first gap, or the boundaries of the first electrode and the first gap coincide with each other; and / or, The second electrode is located in the area enclosed by the boundary of the second gap, or the boundaries of the two coincide with each other; The first gap and the second gap are connected through a plurality of through holes distributed in the inactive area; Alternatively, the first gap and the second gap are connected via an annular through hole surrounding the effective area; The piezoelectric layer includes a resonating portion and a lap portion located on the periphery of the resonating portion, wherein the resonating portion is at least partially located in the effective resonating region, the lap portion is located outside the effective resonating region, and the resonating portion and the lap portion are connected to or separated from each other; The overlapping portion and the resonating portion are separated from each other, the first gap and the second gap are connected to form a cavity, and the outer periphery of the resonating portion is exposed in the cavity.

2. The thin film bulk acoustic resonator according to claim 1, wherein Boundaries of projections of the first gap and the second gap in the direction of the piezoelectric layer surround boundaries of projections of the effective resonance region in the direction of the piezoelectric layer.

3. The thin film bulk acoustic resonator according to claim 1, wherein Boundaries of projections of the first gap and the second gap in the direction of the piezoelectric layer surround boundaries of projections of the first electrode and the second electrode in the direction of the piezoelectric layer.

4. The thin film bulk acoustic resonator according to claim 1, wherein The first gap and the second gap are connected to each other, or the first gap and the second gap are isolated from each other.

5. The thin film bulk acoustic resonator according to claim 1, wherein A membrane layer is provided between the first gap and the second gap in the inactive area, and the membrane layer is a piezoelectric layer or a membrane layer made of a material different from that of the piezoelectric layer; Alternatively, the piezoelectric layer is only located in the effective resonance region.

6. The thin film bulk acoustic resonator according to claim 1, wherein The overlapping portion is connected to the resonating portion, the piezoelectric layer is a complete film layer, and the piezoelectric layer isolates the first gap from the second gap.

7. The thin film bulk acoustic resonator according to claim 1, wherein The first conductive protrusion and / or the second conductive protrusion are arranged at a boundary of the effective resonance region.

8. The thin film bulk acoustic resonator according to claim 1, wherein At least part of the first conductive protrusions is disposed at a boundary of the first gap; And / or, at least part of the second conductive protrusions are arranged at the boundary of the second gap.

9. The thin film bulk acoustic resonator according to claim 1, wherein The projection of the first conductive protrusion and / or the second conductive protrusion in the direction of the piezoelectric layer is a closed or discontinuous ring.

10. The thin film bulk acoustic resonator according to claim 7, wherein The projections of the first conductive protrusion and the second conductive protrusion in the direction of the piezoelectric layer at least partially overlap, or one of them is located at the periphery of the other.

11. The thin film bulk acoustic resonator according to claim 5, wherein The first conductive protrusion is arranged at the boundary of the first gap, or the first conductive protrusion is provided with a distance from the boundary of the first gap, or a part of the first conductive protrusion is arranged at the boundary of the first gap, and another part of the first conductive protrusion is provided with a distance from the boundary of the first gap; and / or the second conductive protrusion is arranged at the boundary of the second gap, or the second conductive protrusion is provided with a distance from the boundary of the second gap, or a part of the second conductive protrusion is arranged at the boundary of the second gap, and another part of the second conductive protrusion is provided with a distance from the boundary of the second gap.

12. The thin film bulk acoustic resonator according to claim 1, wherein The first electrode lead-out portion is buried in the first dielectric layer; and / or the second electrode lead-out portion is buried in the second dielectric layer.

13. The thin film bulk acoustic resonator according to claim 1, wherein Outside the effective resonance region, projections of the first electrode lead portion and the second electrode lead portion in the direction of the piezoelectric layer are staggered with each other.

14. The thin film bulk acoustic resonator according to claim 1, wherein A first release hole is provided in the first dielectric layer opposite to the first gap and / or a second release hole is provided in the second dielectric layer opposite to the second gap. The first release hole and the second release hole are filled with dielectric material.

15. The thin film bulk acoustic resonator according to claim 1, wherein The material of the first conductive protrusion or the second conductive protrusion or the first electrode lead portion or the second electrode lead portion includes: gold, silver, tungsten, platinum, aluminum, and copper.

16. A method for manufacturing a thin film bulk acoustic resonator according to any one of claims 1 to 2 and 7 to 15, characterized in that: include: forming a first structure, the first structure comprising: a first electrode, a first sacrificial layer at least covering the first electrode, and a dielectric layer surrounding the first sacrificial layer at least on a side surface of the first sacrificial layer; forming a first conductive protrusion, penetrating the first sacrificial layer and having one end connected to the first electrode; forming a first electrode lead-out portion, one end of which is connected to the other end of the first conductive protrusion and the other end of which extends out of the effective resonance region; forming a piezoelectric layer; forming a second structure, the second structure comprising: a second electrode, a second sacrificial layer at least covering the second electrode, and a dielectric layer surrounding the second sacrificial layer at least on a side surface of the second sacrificial layer; forming a second conductive protrusion, penetrating the second sacrificial layer and having one end connected to the second electrode; forming a second electrode lead-out portion, one end of which is connected to the other end of the second conductive protrusion and the other end of which extends out of the effective resonance region; The first sacrificial layer and the second sacrificial layer are removed to form the first gap and the second gap.

17. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: Also includes: providing a temporary substrate; forming the first structure, the first conductive protrusion, and the first electrode lead-out portion in sequence on the temporary substrate; Bonding a carrier substrate to the side where the first electrode lead-out portion is located, and removing the temporary substrate; The second structure, the second conductive protrusion, and the second electrode lead-out portion are sequentially formed on the carrier substrate.

18. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: Also includes: providing a carrier substrate; Firstly forming the first electrode lead-out portion on the carrier substrate, and then forming the first structure and the first conductive protrusion; Then, the second structure, the second conductive protrusion, and the second electrode lead-out portion are formed.

19. The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein: Also includes: providing a temporary substrate; forming the first structure, the piezoelectric layer, the second structure, the second conductive protrusion, and the second electrode lead-out portion in sequence on the temporary substrate; bonding a carrier substrate to the side where the second electrode lead-out portion is located, and then removing the temporary substrate; After bonding the carrier substrate, the first conductive protrusion and the first electrode lead-out portion are formed in sequence.

20. The method for manufacturing a thin film bulk acoustic resonator according to any one of claims 17 to 19, wherein: forming a second electrode layer, a piezoelectric layer, and a first electrode layer in sequence; patterning the first electrode layer to form the first electrode; After forming the first structure, patterning the second electrode layer to form a second electrode; The integrity of the piezoelectric layer is retained, and the first gap and the second gap are separated from each other by the piezoelectric layer; or, forming a first electrode layer, a piezoelectric layer, and a second electrode layer; patterning the first electrode layer to form the first electrode; After forming the first structure, patterning the second electrode layer to form a second electrode; After forming the first electrode or after forming the second electrode, patterning the piezoelectric layer to remove the piezoelectric layer in the ineffective region or forming an air gap around the piezoelectric layer in the effective resonance region; or, forming a first electrode layer, a piezoelectric layer, and a second electrode layer; Patterning the first electrode layer, the piezoelectric layer, and the second electrode layer, and removing portions of the first electrode layer, the piezoelectric layer, and the second electrode layer located in an inactive area to form the first electrode, the second electrode, and the piezoelectric layer; Then, forming the first sacrificial layer and a dielectric layer surrounding the first sacrificial layer at least on the side surface of the first sacrificial layer, wherein the first sacrificial layer covers the top surface and side surfaces of the first electrode, the second electrode, and the piezoelectric layer; or, forming a first electrode layer, a piezoelectric layer, and a second electrode layer; patterning the first electrode layer to form the first electrode; forming the first sacrificial layer and a dielectric layer surrounding the first sacrificial layer at least on a side surface of the first sacrificial layer, wherein the first sacrificial layer covers a top surface and side surfaces of the first electrode; patterning the second electrode layer to form the second electrode; After forming the first electrode or after forming the second electrode, patterning the piezoelectric layer to remove the piezoelectric layer in the ineffective region or forming an air gap around the piezoelectric layer in the effective resonance region; or, forming a first electrode and a planar layer, wherein the surfaces of the first electrode and the planar layer are flush; forming a piezoelectric layer on the flush surface; forming a second electrode layer on the piezoelectric layer; patterning the second electrode layer to form a second electrode; The piezoelectric layer is located in the effective resonance area and the invalid area; or, before or after patterning the second electrode layer, the piezoelectric layer is patterned to remove the piezoelectric layer in the invalid area or to form an air gap around the piezoelectric layer in the effective resonance area.

21. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: The method of forming the first structure includes: forming a first electrode layer, and patterning the first electrode layer to form the first electrode; forming a first sacrificial layer, wherein the first sacrificial layer covers only the top surface of the first electrode or covers the top surface and side surfaces of the first electrode; forming a dielectric layer surrounding the first sacrificial layer at least on the side of the first sacrificial layer, covering the side of the first sacrificial layer and the side of the first electrode, or covering the side, top surface and side of the first sacrificial layer; or, forming a first electrode layer, and patterning the first electrode layer to form the first electrode; forming a dielectric layer that surrounds the first sacrificial layer at least on a side surface of the first sacrificial layer, covering the first electrode and the surrounding area; The dielectric layer surrounding the first sacrificial layer at least on a side surface of the first sacrificial layer is etched to form a first gap, and the first sacrificial layer is formed in the first gap.

22. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: The method of forming the second structure includes: forming a second electrode layer, and patterning the second electrode layer to form the second electrode; forming a second sacrificial layer, wherein the second sacrificial layer covers only the top surface of the second electrode or covers the top surface and side surfaces of the second electrode; forming a dielectric layer surrounding the second sacrificial layer at least on the side surfaces of the second sacrificial layer, covering the side surfaces of the second sacrificial layer and the side surfaces of the second electrode, or covering the side surfaces, the top surface of the second sacrificial layer and the side surfaces of the second electrode; or, forming a second electrode layer, and patterning the second electrode layer to form the second electrode; forming a dielectric layer surrounding the second sacrificial layer at least on a side surface of the second sacrificial layer, covering the second electrode and the surrounding area; The dielectric layer surrounding the second sacrificial layer at least on a side surface of the second sacrificial layer is etched to form a second gap, and the second sacrificial layer is formed in the second gap.

23. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: Forming the first conductive protrusion includes: patterning the film layer between the first electrode and the first electrode lead-out portion to form a first through hole; Filling the first through hole with a conductive material to form the first conductive protrusion; and / or, Forming the second conductive protrusion includes: patterning the film layer between the second electrode and the second electrode lead-out portion to form a second through hole; The second through hole is filled with a conductive material to form the second conductive protrusion.

24. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: Forming the first electrode lead-out portion includes: forming a first passivation layer; etching the first passivation layer to form a first groove; forming a first conductive layer in the first groove as the first electrode lead-out portion; or, forming a first conductive layer, and patterning the first conductive layer to form the first electrode lead-out portion; forming a first passivation layer to cover the first electrode lead-out portion; The dielectric layer surrounding the first sacrificial layer at least on the side of the first sacrificial layer includes the first passivation layer.

25. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: Forming the second electrode lead-out portion includes: forming a second passivation layer; etching the second passivation layer to form a second groove; forming a second conductive layer in the second groove as the second electrode lead-out portion; or, forming a second conductive layer, and patterning the second conductive layer to form the second electrode lead-out portion; forming a second passivation layer to cover the second electrode lead-out portion; The dielectric layer surrounding the second sacrificial layer at least on the side of the second sacrificial layer includes the second passivation layer.

26. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: The first sacrificial layer is formed before the second sacrificial layer, and removing the first sacrificial layer and the second sacrificial layer comprises: removing the first sacrificial layer before forming the second sacrificial layer or removing the first sacrificial layer and the second sacrificial layer after forming the second sacrificial layer; or, After the first sacrificial layer is formed on the second sacrificial layer, removing the first sacrificial layer and the second sacrificial layer comprises: removing the second sacrificial layer before forming the first sacrificial layer or removing the first sacrificial layer and the second sacrificial layer after forming the first sacrificial layer; or, The first sacrificial layer and the second sacrificial layer are connected to each other, and the first sacrificial layer and the second sacrificial layer are removed at the same time.

27. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein: The material of the first sacrificial layer or the second sacrificial layer includes: phosphosilicate glass, low-temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist.

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