WO2022134196A1 - 薄膜体声波谐振器及其制造方法和滤波器 - Google Patents

薄膜体声波谐振器及其制造方法和滤波器 Download PDF

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Publication number
WO2022134196A1
WO2022134196A1 PCT/CN2020/142519 CN2020142519W WO2022134196A1 WO 2022134196 A1 WO2022134196 A1 WO 2022134196A1 CN 2020142519 W CN2020142519 W CN 2020142519W WO 2022134196 A1 WO2022134196 A1 WO 2022134196A1
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Prior art keywords
thin film
substrate
electrode
piezoelectric
bulk acoustic
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PCT/CN2020/142519
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English (en)
French (fr)
Inventor
郑根林
张树民
牛玉娇
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杭州左蓝微电子技术有限公司
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Priority claimed from CN202011567369.2A external-priority patent/CN114696767A/zh
Priority claimed from CN202011568972.2A external-priority patent/CN112886939A/zh
Priority claimed from CN202011565189.0A external-priority patent/CN114696766A/zh
Application filed by 杭州左蓝微电子技术有限公司 filed Critical 杭州左蓝微电子技术有限公司
Publication of WO2022134196A1 publication Critical patent/WO2022134196A1/zh

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator

Definitions

  • the present application relates to the technical field of microelectronic devices, in particular to the technical field of surface acoustic waves, and in particular to a thin-film bulk acoustic wave resonator, a method for manufacturing the thin-film bulk acoustic wave resonator, and a filter having the thin-film bulk acoustic wave resonator.
  • the wireless communication related technologies people's requirements for data transmission are getting higher and higher, especially in the field of mobile communication. With the advent of the era of 3G, 4G, 5G and the future development of 6G, its network transmission rate and network capacity will be greatly improved. .
  • the wireless space is limited. As the data rate increases, it corresponds to the high utilization rate of spectrum resources and the complexity of the communication protocol.
  • various performances of the radio frequency system are also put forward higher requirements.
  • the RF filter plays a crucial role, and the filter based on the thin film bulk acoustic resonator can be selected in the high frequency band.
  • the thin film bulk acoustic wave resonator in the related art has problems of large energy loss, poor reliability and stability.
  • the piezoelectric film stack structure of the thin film bulk acoustic wave resonator is anchored on the substrate, and the anchoring is carried out by widening and thickening the electrodes of the thin film bulk acoustic wave resonator.
  • the anchoring energy loss (anchor loss)
  • the sound wave leaks through the anchoring joint
  • the riveted joint is prone to fracture, and the free vibration of the piezoelectric film stack structure is limited, which affects the performance of the resonator.
  • the present application aims to solve one of the technical problems existing in the related art at least to a certain extent.
  • Embodiments of the present application provide a thin film bulk acoustic resonator with high stability.
  • Embodiments of the present application provide a filter having the above-mentioned thin film bulk acoustic resonator.
  • Embodiments of the present application provide a method of manufacturing a thin film bulk acoustic resonator.
  • Embodiments of the present application provide a thin film bulk acoustic resonator manufactured according to the above-described manufacturing method.
  • a thin film bulk acoustic resonator includes: a substrate and a piezoelectric thin film stack structure, the substrate has a cavity, the piezoelectric thin film stack structure is connected to the substrate, and at least a portion of the piezoelectric thin film stack structure is connected to the substrate. A portion is suspended above the cavity.
  • a support structure is disposed in the cavity, and the piezoelectric film stack structure is not in direct contact with the support structure.
  • the piezoelectric thin film stack includes a piezoelectric layer, a first electrode on the piezoelectric layer and in at least partial contact with an upper surface of the piezoelectric layer, and a piezoelectric layer on the piezoelectric layer a second electrode under and at least partially in contact with the lower surface of the piezoelectric layer, a gap portion between the piezoelectric film stack structure and the support structure or the piezoelectric film stack structure and the support structure There is a Bragg reflection structure in between.
  • the shape of the support structure is one or more of a column shape, a boss shape, a cone shape, a sphere shape, and a spherical shape.
  • the height of the slit portion is 1 ⁇ m-5 ⁇ m, or the height of the upper end of the Bragg reflection structure from the lower surface of the piezoelectric thin film stack structure is 1 ⁇ m-5 ⁇ m.
  • the support structure is disposed adjacent to the bond between the substrate and the piezoelectric thin film stack.
  • the support structure is integrally formed with the bottom wall of the cavity or is in direct contact with the bottom of the cavity.
  • the support structure is plural.
  • a Bragg reflection structure is disposed between the support structure and the piezoelectric thin film stack structure, and the number of layers of the Bragg reflection structure is multiple layers.
  • the piezoelectric film stack structure has at least one elastic connection structure, and the piezoelectric film stack structure is connected to the substrate through the at least one elastic connection structure.
  • the piezoelectric thin film stack structure further includes: a first electrode, a piezoelectric layer, a second electrode and at least one elastic connection structure, the piezoelectric layer is located between the first electrode and the second electrode between the electrodes, and the first electrode and the second electrode are arranged opposite to each other.
  • the at least one elastic connection structure is integrally formed with at least one of the first electrode and the second electrode.
  • the shape of the at least one elastic connecting structure is a zigzag shape, a square wave shape, a wave shape, an omega shape or a spring shape.
  • the substrate includes: a first insulating layer, a silicon dioxide layer, a second insulating layer, and a metal layer; the cavity is formed in the second insulating layer and the metal layer, the At least one of the first electrode and the second electrode is connected to the metal layer through the at least one elastic connection structure.
  • the at least one elastic connecting structure is made of at least one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, and aluminum.
  • the thin film bulk acoustic resonator further includes at least one support connection, and the piezoelectric thin film stack structure is connected to the surface of the substrate through the at least one support connection.
  • the piezoelectric thin film stack structure includes: a first electrode, a piezoelectric layer and a second electrode,
  • the piezoelectric layer is located between the first electrode and the second electrode, and the first electrode and the second electrode are arranged opposite to each other, and at least one of the first electrode and the second electrode is connected to the surface of the substrate by means of the at least one support connector.
  • the at least one support connection is disposed between at least one of the first electrode and the second electrode and the substrate.
  • one end of the support connector is connected to the substrate, and the other end of the support connector extends into the cavity and is connected to at least one of the first electrode and the second electrode. one connection.
  • the at least one support connector is integrally formed with at least one of the first electrode and the second electrode.
  • a filter according to an embodiment of the present application includes the thin film bulk acoustic wave resonator according to any of the above embodiments.
  • a method for manufacturing a thin film bulk acoustic resonator includes: providing a substrate with a cavity; providing a piezoelectric thin film stack structure; connecting the piezoelectric thin film stack structure with the substrate and making the piezoelectric thin film stack At least a portion of the thin film stack is suspended above the cavity.
  • the method further includes forming a support structure within the cavity, wherein the piezoelectric thin film stack is not in direct contact with the support structure,
  • the cavity is formed within the substrate by etching.
  • forming a support structure within the cavity includes post-plating photolithography on the substrate having the cavity, wherein the photolithography includes gluing, exposing, and developing.
  • the piezoelectric thin film stack is connected to the substrate by bonding.
  • providing the piezoelectric thin film stack structure includes: providing a transfer substrate; and sequentially depositing a first electrode, a piezoelectric layer, and a second electrode on the transfer substrate to form the piezoelectric thin film stack structure;
  • the bonding of the electric thin film stack structure and the substrate includes: placing the piezoelectric thin film stack structure directly above the cavity, and bonding the second electrode and a part of the upper surface of the substrate through a bonding process adhering to each other; and peeling off the transfer substrate, so that the piezoelectric thin film stack structure is at least partially suspended above the cavity.
  • the providing the piezoelectric thin film stack structure includes: filling a sacrificial layer in the cavity of the substrate; depositing the second electrode, the piezoelectric film on the sacrificial layer in sequence from bottom to top layer and the first electrode to form the piezoelectric thin film stack structure.
  • the method further includes providing a release substrate and preparing a piezoelectric thin film stack structure having at least one elastic connection structure on the release substrate; connecting the piezoelectric film stack structure with the piezoelectric film stack structure through the at least one elastic connection structure The substrates are connected; and the peeling substrate is peeled off to form the thin film bulk acoustic resonator.
  • providing a peeling substrate and preparing a piezoelectric thin film stack structure with at least one elastic connection structure on the peeling substrate comprising: providing the peeling substrate, and coating a photolithography layer on the peeling substrate; etching the lithography layer to form a plurality of lithography bumps in a predetermined area on the peeling substrate; depositing a first electrode, a piezoelectric layer and a second electrode in sequence on the peeling substrate, so as to The at least one elastic connection structure is formed on the plurality of photolithographic bumps, thereby obtaining the piezoelectric thin film stack structure having the at least one elastic connection structure.
  • the method further includes: etching a plurality of lithographic bumps in the piezoelectric thin film stack structure to obtain the thin film bulk acoustic resonator.
  • the providing a substrate with a cavity includes: providing a silicon dioxide layer, the silicon dioxide layer having a first surface and a second surface disposed oppositely; on the first surface of the silicon dioxide layer depositing a first insulating layer on one side and depositing a second insulating layer on the second side of the silicon dioxide layer; etching the second insulating layer according to a preset size to forming the cavity; depositing a metal layer on the surface of the second insulating layer to obtain the substrate with the cavity.
  • providing a release substrate and fabricating a piezoelectric thin film stack structure having at least one elastic connection structure on the release substrate includes: providing the release substrate, depositing a buffer layer on the release substrate; The piezoelectric thin film stack structure with at least one elastic connection structure is prepared on the buffer layer.
  • the photolithographic protrusions are hemispherical, triangular, cylindrical or rectangular parallelepiped.
  • the at least one elastic connection structure is integrally formed with at least one of the first electrode and the second electrode.
  • the method further includes: forming at least one support connection on the substrate; fabricating the piezoelectric thin film stack on the at least one support connection to connect by the at least one support A member connects the piezoelectric thin film stack to the surface of the substrate.
  • forming at least one support connector on the substrate includes: filling a cavity of the substrate with a sacrificial layer; depositing a support material on the sacrificial layer to form a support layer; A patterned photoresist layer is formed on the support layer; the support layer is etched and the photoresist layer is removed to obtain the at least one support connector.
  • fabricating the piezoelectric thin film stack on the at least one support connector includes:
  • a second electrode, a piezoelectric layer and a first electrode are sequentially deposited on the at least one supporting connector from bottom to top to form the piezoelectric thin film stack structure on the at least one supporting connector.
  • fabricating the piezoelectric thin film stack on the at least one support connector further includes:
  • a peeling substrate is provided, and a first electrode, a piezoelectric layer and a second electrode are sequentially deposited on the peeling substrate to form the piezoelectric thin film stack structure; the piezoelectric thin film stack structure is placed on the positive side of the cavity Above, the second electrode and the at least one supporting connector are attached to each other through a bonding process; the peeling substrate is peeled off to form the piezoelectric thin film stack structure on the at least one supporting connector.
  • the at least one support connector is integrally formed with at least one of the first electrode and the second electrode.
  • the thin film bulk acoustic wave resonator according to the embodiment of the present application is manufactured according to the method for manufacturing a thin film bulk acoustic wave resonator described in any one of the above embodiments.
  • FIG. 1 is a schematic diagram of a thin film bulk acoustic wave resonator according to a first embodiment of the present application.
  • FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 .
  • FIG 3 is a cross-sectional view of a thin film bulk acoustic wave resonator according to a second embodiment of the present application.
  • FIG. 4 is a cross-sectional view of a thin film bulk acoustic wave resonator according to a third embodiment of the present application.
  • 5A-5D illustrate the flow of a method for manufacturing a thin film bulk acoustic resonator according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a thin film bulk acoustic wave resonator according to a fourth embodiment of the present application.
  • FIG. 7 is a flowchart of a method for manufacturing a thin film bulk acoustic wave resonator according to another embodiment of the present application.
  • FIG. 8 is a specific flowchart of step S101 in FIG. 7 .
  • FIGS. 9A-9C illustrate the manufacturing process of the piezoelectric thin film stack structure of the thin film bulk acoustic wave resonator according to the fourth embodiment of the present application.
  • FIGS. 10A-10C illustrate a manufacturing process of the substrate of the wet thin film bulk acoustic wave resonator according to the fourth embodiment of the present application.
  • FIG. 11 schematically shows the bonding of the substrate of the thin film bulk acoustic wave resonator and the piezoelectric thin film stack structure according to the fourth embodiment of the present application.
  • FIG. 12 schematically shows the peeling of the peeling substrate.
  • FIG. 13 is a top view of a thin film bulk acoustic resonator according to a fourth embodiment of the present application.
  • FIG. 14 is a cross-sectional view of a thin film bulk acoustic wave resonator according to a fifth embodiment of the present application.
  • FIG. 15 is a top view of a thin film bulk acoustic wave resonator according to a sixth embodiment of the present application.
  • 16 is a top view of a thin film bulk acoustic wave resonator according to a seventh embodiment of the present application.
  • FIG. 17 is a flowchart of a method for manufacturing a thin film bulk acoustic resonator according to yet another embodiment of the present application.
  • FIGS. 18A-18D schematically illustrate the manufacturing process of the support connector of the thin film bulk acoustic wave resonator according to the embodiment of the present application.
  • FIG. 19 is a schematic diagram of a substrate of a thin film bulk acoustic wave resonator according to an embodiment of the present application.
  • Piezoelectric film stack structure 10 first electrode 11; piezoelectric layer 12; second electrode 13;
  • the supporting connector 300 , the sacrificial layer 400 , and the supporting layer 500 are supported.
  • first and second are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as “first” or “second” may expressly or implicitly include one or more of that feature.
  • plurality means two or more, unless otherwise expressly and specifically defined.
  • the terms “installed”, “connected” and “connected” should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; may be mechanical connection or electrical connection; may be direct connection or indirect connection through an intermediate medium, may be internal communication between two elements or an interaction relationship between the two elements.
  • installed should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; may be mechanical connection or electrical connection; may be direct connection or indirect connection through an intermediate medium, may be internal communication between two elements or an interaction relationship between the two elements.
  • a first feature "on” or “under” a second feature may include direct contact between the first and second features, or may include the first and second features Not directly but through additional features between them.
  • the first feature being “above”, “over” and “above” the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature.
  • the first feature is “below”, “below” and “below” the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.
  • the thin film bulk acoustic wave resonator 100 includes a substrate 20 (which may also be referred to as a substrate) and a piezoelectric thin film stack structure 10 (which may also be referred to as a piezoelectric sandwich structure).
  • the substrate 20 has a cavity 30 (also referred to as a groove), the piezoelectric film stack structure 10 is connected to the substrate 20 , and at least a part of the piezoelectric film stack structure 10 is suspended above the cavity 30 .
  • the stability and reliability of the thin film acoustic wave resonator can be improved to a certain extent.
  • resonators especially thin-film bulk acoustic resonators
  • the inventors believe that, compared with LC oscillators, ceramic dielectric resonators and surface acoustic wave (SAW) devices used to form band-pass filters and microwave oscillation sources in the related art, thin-film bulk acoustic wave resonators not only have small size,
  • SAW surface acoustic wave
  • its preparation process can be compatible with CMOS technology, so it can form a single-chip system with peripheral circuits, greatly reducing the size and size of the system. power consumption.
  • the thin-film bulk acoustic resonator (FABR) is mainly completed by sacrificial surface process or back etching process. Deposited on its surface, the sacrificial layer is removed later in the process to form the cavity.
  • the inventor believes that the preparation process of the thin-film bulk acoustic wave resonator device is not complicated compared with other MEMS devices, but the backside etching process is mainly by etching the bulk silicon on the backside of the wafer, so that the piezoelectric film formed on the front side is formed.
  • the backside of the stacked structure is in a cavity environment.
  • the main problem of the backside etching process is that a layer of silicon dioxide and a layer of silicon nitride film are required as the supporting layer of the piezoelectric film stacking structure, so that the device can avoid the etching solution during the process production.
  • a design is prone to large stress, and the device is prone to wrinkles and cracks, which will greatly affect the performance of the device.
  • high-performance FBAR devices cannot be fabricated.
  • Disposing the support structure in the cavity can avoid the above problems to a certain extent, but it may cause the performance of the device itself to be degraded because the acoustic energy of the piezoelectric layer leaks out to the base structure through the support structure.
  • the embodiment of the first aspect of the present application provides a thin film bulk acoustic wave resonator whose performance of a delay device is degraded.
  • a support structure in the cavity and the support structure is not in direct contact with the piezoelectric thin film stack structure, on the one hand, sound energy can be prevented from passing through.
  • the performance of the device is degraded due to the leakage of the support structure.
  • the support structure by setting the support structure, if the device collapses after a period of operation, the support structure can support the piezoelectric film stack structure to a certain extent, avoiding the bonding of the device.
  • the performance of the thin-film bulk acoustic wave resonator is severely damaged.
  • the thin film bulk acoustic wave resonator proposed in the embodiments of the present application can be widely used in communication devices and is used as one of the main components of the filter in the communication system.
  • Resonators can also be used in other systems that require frequency filtering, such as RF oscillators, filters, and duplexers.
  • the thin film bulk acoustic wave resonator according to the embodiment of the first aspect of the present application will be described below with reference to FIGS. 1-5D .
  • FIG. 2 is a cross-sectional view along line A-A in FIG. 1 , a thin film bulk acoustic resonator 100 according to an embodiment of the first aspect of the present application includes a substrate 20 and a piezoelectric thin film stack structure 10 .
  • the substrate 20 has a cavity 30 , a support structure 40 is disposed in the cavity 30 , and the piezoelectric film stack structure 10 is not in direct contact with the support structure 40 .
  • the piezoelectric film stack structure 10 and the support structure 40 are spaced apart or provided with an intermediate medium
  • the substrate 20 may be selected as an insulating substrate 20 .
  • the cavity 30 is disposed inside the insulating base 20 , and the upper end of the cavity 30 is substantially flush with the upper surface of the base 20 .
  • the cavity 30 is formed in the insulating base 20 and the cavity 30 is an open structure with an open upper end.
  • the substrate 20 may be an SOI substrate.
  • the substrate 20 can be a common silicon substrate, and can also be a glass substrate, an organic material substrate, a quartz substrate, or any other substrate suitable for preparing a carrier for a thin film bulk acoustic resonator (FBAR).
  • FBAR thin film bulk acoustic resonator
  • the piezoelectric film stack structure 10 also known as a piezoelectric sandwich structure, includes a first electrode (also known as a top electrode) 11, a piezoelectric layer 12 (also known as a piezoelectric crystal, a piezoelectric film, and a piezoelectric film) stacked sequentially from top to bottom. ), the second electrode (also referred to as the bottom electrode) 13 .
  • the first electrode 11 is located above the piezoelectric layer 12 and is at least partially in contact with the upper surface of the piezoelectric layer 12, the second electrode 13 is located under the piezoelectric layer 12 and is at least partially in contact with the lower surface of the piezoelectric layer 12, and the piezoelectric
  • the thin film stack structure 10 is at least partially suspended above the cavity 30 .
  • the cavity 30 can be formed by dry etching, and the size of the cavity 30 approximately matches the piezoelectric thin film stack structure 10 .
  • the projection of the cavity 30 and the projection of the piezoelectric film stack structure 10 at least partially overlap, and the projection of the cavity 30 is slightly smaller than Projection of the piezoelectric thin film stack 10 .
  • the projection of the cavity 30 is slightly larger than the projection of the piezoelectric film stack structure 10 .
  • the projection of the cavity 30 is larger than the projection of the piezoelectric film stack structure 10, and the projection of the piezoelectric film stack structure 10 is all located in the projection of the cavity 30, which can avoid piezoelectric energy loss or leakage to the greatest extent, but it has some disadvantages to the process. Must request.
  • the inventor's research shows that the cavity 30 is roughly an irregular pentagon, that is, along the height direction, in the horizontal plane in FIG. 2 , the projection of the cavity 30 is an irregular pentagon, and the The projection is also an irregular pentagon. Therefore, the reflection of the transverse wave can be better suppressed, the formation of standing waves can be avoided, and the performance of the resonator can be avoided.
  • the cavity 30 is substantially trapezoidal or hexagonal, or the like.
  • the cavity 30 may be substantially an irregular polygon, of course, the cavity 30 may have any other suitable shape.
  • FIG. 2 is a schematic cross-sectional view of the thin film bulk acoustic resonator along the line A-A in FIG.
  • the support structure 40 is arranged in the cavity 30, and the lower end of the support structure 40 is connected with the bottom wall of the cavity 30, and the connection can be a fixed connection, such as integral molding or welding, or a non-fixed connection,
  • the support structure 40 is only placed in the cavity 30 and is in contact with the bottom wall of the cavity 30 by gravity.
  • the upper end of the support structure 40 is not in direct contact with the piezoelectric film stack structure 10 .
  • there may be a gap portion 50 between the piezoelectric film stack structure 10 and the support structure 40 in other words, the piezoelectric film stack structure 10 and the support structure 40 are not in direct contact in the height direction. In this way, during the operation of the system, the acoustic energy in the piezoelectric film stack structure 10 will not leak to the support structure 40, thereby avoiding signal attenuation or signal error in the system.
  • a gap portion 50 is provided between the support structure 40 and the piezoelectric film stack structure 10 .
  • the height of the gap portion 50 may be 1 ⁇ m-5 ⁇ m, that is, the support structure
  • the height of the upper end of 40 from the lower surface of the piezoelectric film stack structure 10 is 1 ⁇ m-5 ⁇ m.
  • the height of the slit portion 50 may be 2 ⁇ m-3 ⁇ m. In other embodiments, the height of the slit portion 50 may be 2.5 ⁇ m.
  • a Bragg reflection structure 60 is disposed along the height direction between the piezoelectric film stack structure 10 and the support structure 40 .
  • the Bragg reflection structure 60 may replace at least part of the slit portion 50 .
  • the upper end of the support structure 40 is provided with the Bragg reflection structure 60 .
  • the Bragg reflector structure 60 is directly connected to the lower end of the piezoelectric thin film stack structure 10 . Due to the existence of the Bragg reflection structure 60 , energy leakage at the piezoelectric thin film stack structure 10 can be avoided to the greatest extent.
  • the Bragg reflection structure 60 and the lower end of the piezoelectric thin film stack structure 10 may have a certain distance, so that energy will not leak, and it can be ensured that when the piezoelectric thin film stack structure 10 collapses, the Bragg reflection structure 60 can recover. To support, to avoid further deterioration of the device.
  • the Bragg reflection structure 60 is also called a Bragg reflection grating, and its main material is a high acoustic impedance material and a low acoustic impedance material alternately arranged to achieve acoustic reflection and avoid energy leakage.
  • the Bragg reflection structure generally has more than two layers. The more layers, the better the reflection effect, but the relative cost will also increase. Therefore, it is preferably set to four layers, and the height of each layer is a quarter of the wavelength period. Such an arrangement can achieve a greater degree of wave reflection.
  • the material of the reflective layer is as follows:
  • the high acoustic impedance layer may alternatively comprise a solid phase material such as a metal (aluminum, platinum, palladium, tungsten, molybdenum, chromium, titanium, tantalum, or from groups IIIA and/or IVAs of the periodic table of elements) one or more of the elements, or transition metals from one or more of Groups IB, IIB, IIIB, IVB, VB, VIB, VIIB and/or VIIIB), ceramics, glasses, polymers etc.
  • SiC has an acoustic impedance of about 427 ⁇ 106 N.s/m3
  • Ir has an acoustic impedance of about 108 ⁇ 106 N.s/m3
  • W has an acoustic impedance of about 99.9 ⁇ 106 N.s/m3.
  • the optional low acoustic impedance layer 322 may include a gas phase material, or the like, which may include one or more of the following: hydrogen, nitrogen, carbon dioxide, carbon monoxide, oxygen, and/or a Group VIII noble gas (eg, helium). , neon, argon, krypton, xenon) one or more of.
  • the gas-phase material can be an organic material, such as a hydrocarbon substance or a substituted derivative thereof with different functional groups, the gas-phase material can be a mixture of any of the foregoing, and air can be a suitable gas-phase material or mixture having a value of about 0.0004 ⁇ 106N.s/ Low acoustic impedance of m3.
  • a support structure 40 is disposed in the cavity 30 .
  • the support structure 40 may be a part of the insulating base 20 , and the support structure 40 is formed by etching the insulating base 20 .
  • the support structure 40 is formed in the cavity 30, and the support structure 40 is beneficial to reduce the fracture and damage of the thin film bulk acoustic wave resonator during the bonding process, and can effectively improve the production stability of the device , suitable for mass production.
  • the shape of the support structure 40 may be spherical 41 , cylindrical 42 , conical 43 , boss 44 , prism 45 , or the like.
  • the number of support structures 40 may be more than one.
  • the support structure 40 may be one or a combination of the above-mentioned shape structures.
  • the column shape 41 is relatively easy to form by etching, and the column shape 41 may be a column or a prism, which is less difficult in terms of process. Similarly, other shapes can also be formed by etching, but the etching solution, etching rate, etc. need to be controlled, and the process is relatively difficult.
  • the formation of the supporting structure 40 by etching the substrate 20 may be referred to as an integral molding of the substrate 20 and the supporting structure 40 .
  • the spherical shape 41 can be formed not only by etching, but also by other methods, for example, by making a spherical structure of suitable size, and then placing it into the cavity 30 .
  • the suitable size means that the ball 41 is in contact with the bottom 31 of the cavity 30 after being placed in the cavity 30, but the ball 41 does not contact the piezoelectric film stack structure 10 in the height direction, or the top of the ball is in contact with the piezoelectric film stack structure 10.
  • the second electrode 13 is not in direct contact. That is, the support structure 40 and the base 20 are not integrally formed. In this way, the difficulty of the process can be reduced.
  • the support structure 40 may be non-fixedly connected to the bottom of the cavity 30 . In other embodiments, the support structure 40 is fixedly connected to the bottom of the cavity 30, eg, welded or glued.
  • the material of the support structure 40 is one or a combination of several metals or non-metals.
  • the material of the substrate 20 can be silicon and its oxide, and the material of the supporting structure 40 can also be silicon and its oxide.
  • the material of the support structure 40 can be the same.
  • the material of the support structure 40 and the base 20 are not integrally formed, the material of the support structure 40 can be selected from a wide range, for example, some metal materials with good deformation properties, such as aluminum, can be selected. It should be noted that, in the same thin-film bulk acoustic resonator, the number of support structures 40 may be one or more, and the materials of multiple support structures 40 may also be the same or different in material and forming process.
  • the piezoelectric film stack structure 10 and the substrate 20 are suspended above the cavity 30 by bonding, and the number of the supporting structures 40 is multiple.
  • the support structure 40 is disposed adjacent to the bond between the substrate 20 and the piezoelectric film stack 10 , that is, in FIG. 2 , near the left and right side walls of the cavity 30 , the bonding place is where the first electrode 11 and/or the second electrode 13 of the piezoelectric thin film stack structure 10 meet with the substrate 20 .
  • This arrangement facilitates the support structure 40 to provide support in a timely manner when the bond is deformed after a long period of time, so as to avoid vicious fracture at the bond, resulting in rapid deterioration of the filter performance.
  • FIG 3 is a schematic cross-sectional view of a thin film bulk acoustic resonator according to another embodiment of the present application.
  • the upper end of the support structure 40 is a Bragg reflection structure 60 , which is in direct contact with the piezoelectric film stack structure 10 , and energy leakage can be better reduced by arranging the Bragg reflection structure 60 .
  • the Bragg reflection structure 60 is not in direct contact with the piezoelectric film stack structure 10 , in other words, there is a certain gap between the Bragg reflection structure 60 and the piezoelectric film stack structure 10 , which can better avoid energy leakage.
  • FIG. 4 shows a schematic cross-sectional view of a thin film bulk acoustic wave resonator according to still another embodiment of the present application.
  • There are three supporting structures 40 all of which are cylindrical, and none of the plurality of supporting structures 40 is in contact with the piezoelectric film stack structure 10 .
  • the lead-out parts of the first electrode 11 and the second electrode 13 are at the same level, which is convenient for connecting lead test.
  • filtering can be realized.
  • the first electrode 11 can be formed by deposition and photolithography to form a desired pattern with a thickness of 100-2000 nm.
  • the material of the first electrode 11 may be one of metals such as tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, aluminum and their alloy materials, or a combination of at least two of the above-mentioned materials.
  • the second electrode 13 can be formed and patterned by a conventional deposition process, and the thickness of the second electrode 13 is 100-2000 nm.
  • the material of the second electrode 13 may be one of metals such as tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, aluminum, or their alloy materials, or a combination of at least two materials.
  • the piezoelectric layer 12 can be formed by depositing the piezoelectric layer 12 with a high C-axis orientation, and the formation method can be selected from one or a combination of physical vapor deposition, chemical vapor deposition, reactive radio frequency magnetron sputtering, atomic layer deposition, and the like. It should be noted that, for the patterning of the piezoelectric layer 12 , the piezoelectric layer 12 may be etched by reactive ion etching or wet etching process to form through holes that lead out the second electrodes 13 .
  • the material of the piezoelectric layer 12 may be one of aluminum nitride (AlN), zinc oxide (ZnO), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), or a combination of at least two of the above materials.
  • a thin film bulk acoustic wave resonator according to an embodiment of the second aspect of the present application is described below.
  • the thin film bulk acoustic wave resonator according to the embodiment of the second aspect of the present application solves the problem that the thin film bulk acoustic wave resonator in the related art is prone to breakage at the bonding connection between the piezoelectric thin film stack structure and the substrate, and improves the performance of the resonator. structural stability.
  • the thin film bulk acoustic resonator specifically includes: a substrate 20 having a cavity 30 and a piezoelectric thin film stack structure 10 .
  • the piezoelectric thin film stack structure 10 includes a first electrode 11 , a piezoelectric layer 12 , a second electrode 13 and at least one elastic connection structure 180 .
  • the piezoelectric layer 12 is located between the first electrode 11 and the second electrode 13, and the first electrode 11 and the second electrode 13 are substantially opposite to each other;
  • the piezoelectric film stack structure 10 is disposed on the cavity 30 of the substrate 20 , and the first electrode 11 and/or the second electrode 13 are fixedly connected to the substrate 20 through the elastic connection structure 180 .
  • the first electrode 11 and/or the second electrode 13 are fixedly connected to the substrate 20 , and the fixed connection may be referred to as an anchoring connection, and the anchoring connection is realized by an elastic connection structure 180 with elastic deformation capability.
  • the material of the first electrode 11 may be one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, aluminum, or a combination of at least two of the above materials.
  • the material of the substrate 20 may be one of single crystal silicon, polycrystalline silicon, glass, quartz or sapphire.
  • the number of elastic connection structures 180 may be one or more.
  • the first electrode 11 or/and the second electrode 13 of the piezoelectric thin film stack structure 10 are connected to the substrate 20 through an elastic connection structure 180 .
  • the elastic connection structure 180 itself has a certain elastic deformation ability, the support stress can be absorbed/released at the connection between the piezoelectric film stack structure 10 and the substrate 20, which reduces the anchor loss on the one hand, and effectively prevents the anchor loss on the other hand.
  • the fracture occurs at the connection, which improves the structural stability of the resonator, thereby improving the stability of the product.
  • the elastic connection structure 180 can store other energy in the propagation process as elastic potential energy, and can convert the elastic potential energy into other forms of energy, which can maintain the suppression of lateral clutter, avoid energy loss to a greater extent, and improve the Filtering performance of the resonator.
  • a first insulating layer 220 , a silicon dioxide layer 210 , a second insulating layer 230 and a metal layer 250 are sequentially arranged on the substrate 20 from bottom to top; in the second insulating layer 230 and the metal layer 250
  • the cavity 30 is arranged so that the piezoelectric film stack structure 10 is arranged on the cavity 30 , and the first electrode 11 and/or the second electrode 13 are fixedly connected to the metal layer 250 through the elastic connection structure 180 .
  • the substrate 20 includes only single crystal silicon.
  • the elastic connection structure 180 and the first electrode 11 are integrally formed, and/or the elastic connection structure 180 and the second electrode 13 are integrally formed.
  • the shape of the elastic connection structure 180 may be a zigzag shape, a square wave shape, a wave shape, an ⁇ shape or a spring shape.
  • the material of the elastic connection structure 180 includes one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, and aluminum, or a combination of at least two of the above materials.
  • the setting positions of the elastic connecting structures 180 can be set in alignment, that is, the multiple elastic connecting structures 180 are arranged opposite to each other, and from a mechanical point of view, the connecting structures are relatively stable.
  • the position of the elastic connection structure 180 can be set arbitrarily, for example, it can be set only at one corner, or set at a diagonal corner.
  • the elastic connection structure 180 is only a schematic top view in FIG. 13 , in fact, the elastic connection structure 180 includes but is not limited to a hemispherical shape, a triangular shape, a cylindrical shape or a rectangular parallelepiped shape.
  • FIG. 13 shows two elastic connection structures 180 that are not oppositely arranged.
  • One or more elastic connection structures can be set at any position according to actual needs, and only the first electrode 11 and the elastic connection structure 180 are shown in FIG. 13 . , the arrangement of the second electrode 13 and the elastic connection structure 180 may be the same as or similar to the present embodiment.
  • each edge of the lower electrode of the thin film bulk acoustic wave resonator in the related art is anchored with the edge of the cavity 30, thereby limiting the piezoelectric thin film
  • the problem of free vibration of the stacked structure 10 reduces electrical losses and improves the filtering performance of the thin film bulk acoustic wave resonator.
  • a thin film bulk acoustic wave resonator which includes a substrate with a cavity and a piezoelectric thin film stack structure with an upper electrode, a piezoelectric layer and a lower electrode, and each edge of the lower electrode is anchored with the edge of the cavity. catch.
  • the inventor found through research that each edge of the lower electrode is anchored with the edge of the cavity, which limits the free vibration of the piezoelectric thin film stack structure, thereby affecting the filtering performance of the thin film bulk acoustic wave resonator.
  • the thin film bulk acoustic resonator includes: a substrate 20 having a cavity 30 , a piezoelectric thin film stack structure 10 and at least A support link 300 is provided.
  • the piezoelectric thin film stack structure 10 is disposed on the cavity 30 of the base 20 and is fixedly connected to the surface of the base 20 through at least one support connection 300 . Specifically, the piezoelectric film stack structure 10 is fixedly connected to the surface of the substrate 20 through the support connector 300 , that is, the piezoelectric film stack structure 10 is anchored to the surface of the substrate 20 through the support connector 300 , and the anchoring is realized by the support connector 300 .
  • the cavity 30 is an irregular polygon, and/or the piezoelectric thin film stack structure 10 is an irregular polygon, and anchoring can be performed on any side of the polygon. In other embodiments, anchoring can be performed on any of the sides of the above-mentioned polygon.
  • Irregular polygons can be pentagons. In some alternative embodiments, the polygons may be quadrilaterals, hexagons, heptagons.
  • the first electrode 11 or/and the second electrode 13 of the piezoelectric film stack structure 10 are fixedly connected to the substrate 20 through the supporting connectors 300 .
  • the anchoring area of the first electrode 11 or the second electrode 13 is reduced, so that at the anchoring point It has a large elastic deformation ability, which is beneficial to the free vibration of the piezoelectric film stack structure 10 above the cavity 30, thereby reducing the anchor loss and improving the filtering performance of the resonator.
  • the cavity 30 is an effective area.
  • the electrodes around the cavity 30 have electrical losses. In the embodiment of the present application, reducing the electrodes to the inside of the cavity 30 can eliminate this part of the loss.
  • the support connector 300 has a certain deformability, and when the resonator is working, other forms of energy leaked from the piezoelectric stack structure can be stored as elastic potential energy to a certain extent, and the energy can be stored by deformation to a certain extent. And then re-converted to the piezoelectric stack structure, the lateral clutter is suppressed to a certain extent, the energy loss is reduced to a greater extent, the performance of the resonator is further improved, and its Q value is improved.
  • the piezoelectric thin film stack structure 10 includes: a first electrode 11, a piezoelectric layer and a second electrode 13; the piezoelectric layer is located between the first electrode 11 and the second electrode 13, and the first electrode 11 and The second electrodes 13 are disposed opposite to each other, and the first electrodes 11 or/and the second electrodes 13 are fixedly connected to the surface of the substrate 20 through the support connecting member 300 .
  • the material of the first electrode 11 may be one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, aluminum, or a combination of at least two of the above materials.
  • the material of the second electrode 13 is one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium-tungsten, and aluminum, or a combination of at least two of the above materials.
  • the material of the substrate 20 is one of single crystal silicon, polycrystalline silicon, glass, quartz or sapphire.
  • FIG. 15 is a schematic top view corresponding to FIG. 14 .
  • the supporting connector 300 is disposed between the second electrode 13 and the substrate 20 , and the supporting connector 300 is One end is fixedly connected to the base 20 , and the other end of each support connector 300 extends into the cavity 30 and is connected to the second electrode 13 .
  • the number, shape and position of the supporting connectors 300 are not limited to those shown in the drawings, and can be adjusted according to the actual application scene of the resonator and the size of the resonator, as long as it can play a supporting role and is compatible with the second electrode 13
  • the contact area of may be smaller than the contact area of the second electrode 13 and the substrate 20 .
  • a first insulating layer 220 , a silicon dioxide layer 210 , a second insulating layer 230 and a metal layer 250 are sequentially disposed on the substrate 20 from bottom to top.
  • the cavity 30 is provided in the second insulating layer 230 and the metal layer 250 , the piezoelectric film stack structure 10 is provided on the cavity 30 , and the first electrode 11 and/or the second electrode 13 are fixed to the metal layer 250 through the supporting connector 300 connect.
  • the substrate 20 includes only single crystal silicon.
  • the first electrode 11 is an upper electrode layer
  • the second electrode 13 is a lower electrode layer.
  • the connection between the lower electrode layer and the surface of the substrate 20 is taken as an example.
  • the upper electrode layer is fixedly connected to the surface of the substrate 20, in other words, the upper electrode layer can be fixedly connected to the surface of the substrate 20 through the support connector 300, or the lower electrode layer can be fixedly connected to the surface of the substrate 20 through the support connector 300, or Both the electrode layer and the lower electrode layer are fixedly connected to the surface of the substrate 20 through the support connection member 300 .
  • the material of the support connector 300 includes one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium tungsten, and aluminum, or a combination of at least two of the above materials.
  • the setting position of the support connecting member 300 can be set on the opposite side of the electrode, and from a mechanical point of view, this connection structure is relatively stable.
  • the position of the support connection structure can be set arbitrarily, for example, it can be set only on one side or on the opposite side.
  • the support connector 300 is integrally formed with the first electrode 11 or/and the second electrode 13.
  • a plurality of support connectors 300 are integrally formed with the second electrode 13, as shown in FIG. 15 and FIG.
  • the difference between the embodiments shown in 16 is: FIG. 16 is by forming a support connector 300 with a support function on the second electrode 13, so as to achieve the purpose of reducing the contact area with the surface of the substrate 20; FIG. A supporting connector 300 with a supporting function is added between the surface of the substrate 20 and the surface of the substrate 20 to achieve the purpose of reducing the contact area with the surface of the substrate 20 .
  • the embodiments of the present application further provide a filter having the thin film bulk acoustic resonator described in any of the above embodiments. According to the filter of the embodiment of the present application, the filtering performance and reliability are improved.
  • the piezoelectric film stack 10 is connected to the substrate 20 and at least a portion of the piezoelectric film stack 10 is suspended above the cavity 30 .
  • the manufacturing method of the thin film bulk acoustic resonator according to the embodiment of the present application, by suspending at least part of the piezoelectric thin film stack structure above the cavity of the substrate, the free vibration of the piezoelectric thin film stack structure is reduced to a certain extent Therefore, the filtering performance of the thin film bulk acoustic wave resonator is guaranteed.
  • S01 Provide a substrate, etch the substrate to form a cavity, and form a support structure in the cavity;
  • S02 providing a piezoelectric film stack structure, bonding the piezoelectric film stack structure above the cavity, and not in direct contact with the support structure.
  • S01 includes providing a substrate 20 and etching the substrate 20 to form a cavity 30 .
  • the insulating silicon-based substrate 20 is first prepared, and its surface is cleaned.
  • the insulating silicon-based substrate 20 is silicon, silicon dioxide (BOX), and silicon substrate 20 from top to bottom.
  • the material of the insulating silicon-based substrate 20 can also be selected from other materials.
  • the silicon-on-insulator substrate 20 may be etched dry or wet, and the silicon portion of the upper layer in the etching window is removed to form the cavity 30 , that is, the cavity 30 is formed in the silicon-on-insulator substrate 20 .
  • wet etching mainly refers to the traditional etching method.
  • the silicon wafer is immersed in a certain chemical reagent or reagent solution, so that the part of the film surface that is not masked by the resist chemically reacts with the reagent and is removed.
  • a silicon dioxide film is etched with a solution containing hydrofluoric acid, an aluminum film is etched with phosphoric acid, and the like. This process of etching in a liquid environment is called a "wet" process, which has the advantages of simple operation, low equipment requirements, easy mass production, and good etching selectivity.
  • this etching method not only changes the pattern profile, but also changes the profile when slightly When there is over-etching, the line width of the pattern on the thin film will be smaller than the line width formed on the original resist film on the cross section, which is advantageous to this embodiment.
  • the dry etching is mainly to expose the surface of the silicon wafer to the plasma generated in the air, and the plasma passes through the window opened in the photoresist and undergoes a physical or chemical reaction with the silicon wafer, thereby removing the exposed surface material.
  • This etching method has high anisotropy characteristics and can ensure the accuracy of the pattern, especially for the use of micron and submicron line widths. VLSI has special significance.
  • the manufacturing method of this embodiment adopts dry etching, which can better etch the required support structure 40 .
  • the plating layer 21 can be prepared on the substrate 20 with the cavity 30 structure shown in 5A first, the mask 22 is prepared at the target position in the cavity 30 , and the exposure After post-development, the support structure 40 as shown in FIG. 5C can be prepared. That is, the plating layer 21 is prepared on the substrate 20 having the cavity 30 structure, and then photolithography is performed, and the photolithography includes gluing, exposure, and development to obtain the support structure 40 as shown in the figure.
  • providing the piezoelectric film stack structure 10 and bonding the piezoelectric film stack structure 10 over the cavity 30 includes: providing a peeling substrate 110 (also referred to as a transfer substrate) on the peeling substrate 110
  • the first electrode 11, the piezoelectric crystal and the second electrode 13 are deposited in sequence to form the piezoelectric film stack structure 10; the piezoelectric film stack structure 10 is placed directly above the cavity 30, and the second electrode 13 is formed by a bonding process. and/or part of the upper surfaces of the base 20 are adhered to each other;
  • the release substrate 110 includes a buffer layer (not shown) with a thickness of 50-500 nanometers.
  • the substrate 20 is a silicon substrate 20 .
  • the substrate 20 may also be a glass substrate 20 , an organic material substrate 20 , a quartz substrate 20 , or any other substrate 20 suitable for preparing a carrier for a thin film bulk acoustic resonator (FBAR).
  • the buffer layer is used for subsequent separation and peeling of the substrate 110 and the thin film bulk acoustic resonator (FBAR), and the material of the buffer layer may be silicon dioxide, silicon nitride, silicon oxynitride, phosphate glass and other materials.
  • the silicon dioxide film can be doped with ions, such as phosphorus, fluorine, carbon, boron, etc., for better etching.
  • the depth of the cavity 30 (the dimension of the cavity in the up-down direction in FIG. 2 ) is coordinated with the overall thickness of the piezoelectric thin film stack structure 10 .
  • the cavity 30 has a depth H0
  • the overall thickness of the piezoelectric film stack structure 10 is H1 .
  • the depth H0 of the cavity 30 is greater than the thickness H1 of the piezoelectric film stack structure 10, so that the piezoelectric film stack structure can There is a certain space between the lower surface of the cavity 10 and the bottom wall of the cavity 30 for placing the support structure 40 .
  • the height H3 of the support structure 40 is smaller than the distance H2 between the lower surface of the piezoelectric film stack structure 10 and the bottom of the cavity 30 , and H2 is roughly the difference between H0 and H1 .
  • H2 is roughly the difference between H0 and H1 .
  • a Bragg reflection structure 60 is disposed between the upper end of the support structure 40 and the lower surface of the piezoelectric film stack structure 10 , and the Bragg reflection structure 60 can reflect sound waves to a certain extent, so as to avoid the damage at the piezoelectric film stack structure 10 . Sound energy leaks.
  • the projected area S1 of the cavity 30 along the height direction is larger than the projected area S2 of the piezoelectric thin film stack structure 10 . In this way, the energy leakage of the piezoelectric thin film stack structure 10 can reach a minimum value.
  • the silicon substrate 20 in the cavity 30 is etched by a dry method or a wet method. According to a preset pattern, after etching, a plurality of support structures 40 will be formed in the cavity 30 . And according to different requirements, the number and position of the support structures 40 are also different, and can be set as required.
  • the upper surfaces of the first electrode 11 and the second electrode 13 are finally at the same level on the insulating silicon-based substrate 20 with the cavity 30 , which is convenient for connection lead testing.
  • the insulating silicon-based substrate 20 with the cavity 30 is bonded to the piezoelectric thin film stack structure 10 , and the bonding process is as follows: first, a layer of metal material is deposited on the surface of the insulating silicon-based substrate 20 with the cavity 30 .
  • the metal material can be one of tungsten, molybdenum, platinum platinum, ruthenium, iridium, titanium-tungsten, aluminum, or a combination of at least two of them, with a thickness of 100-2000 nanometers; dry or wet etching process is used to etch the inside of the cavity 30
  • the metal layer 250 is removed, leaving the metal layer 250 outside the cavity 30 and on the support structure 40;
  • the electrodes 13 are aligned, and the two are bonded into a device through a metal bonding process.
  • the metal material may also be pre-deposited on the silicon-on-insulator substrate 20 before the etching step of the cavity 30 with the support structure 40 is started.
  • the support structure 40 is arranged in the cavity 30 and the support structure 40 is not connected to the piezoelectric film stack structure, on the one hand, the performance degradation of the device caused by the sound energy leaking through the support structure 40 can be avoided, and on the other hand
  • the support structure 40 can support the piezoelectric thin film stack structure to a certain extent, so as to avoid the damage of the bonding part of the device and cause serious damage to the performance of the thin film bulk acoustic wave resonator .
  • the method for manufacturing a thin-film bulk acoustic wave resonator specifically includes the following steps. It should be noted that within the allowable range of the process, the order of the following steps can be exchanged:
  • step S101 a peeling substrate 110 is provided, and a piezoelectric film stack structure 10 having at least one elastic connection structure 180 is prepared on the peeling substrate 110 .
  • a peeling substrate 110 is provided, and the piezoelectric film stack structure 10 having at least one elastic connection structure 180 is prepared on the peeling substrate 110 . Specifically, the following steps are included:
  • Step S201 providing a peeling substrate 110, and coating a photoresist layer (also referred to as a photoresist layer) 130 on the peeling substrate 110;
  • Step S202 etching the photolithography layer 130 to form a plurality of photolithography protrusions 140 in a predetermined area on the peeling substrate 110 ;
  • Step S203 depositing the first electrode 11 , the piezoelectric layer 12 and the second electrode 13 in sequence on the peeling substrate 110 having a plurality of photolithographic protrusions 140 , so that at least one elastic connection structure is formed on the plurality of photolithographic protrusions 140 180 , the piezoelectric film stack structure 10 having at least one elastic connection structure 180 is obtained.
  • a peeling substrate 110 is provided, and a buffer layer 120 is deposited on the peeling substrate 110 .
  • the buffer layer 120 is mainly used to facilitate the separation of the peeling substrate 110 from the piezoelectric film stack structure 10 ;
  • Layer 120 may be silicon dioxide, silicon nitride, silicon oxynitride, phosphoric acid lift-off, and the like.
  • a photoresist layer 130 is formed on the buffer layer 120 by spin coating photoresist, a protective film is covered in a predetermined area on the photoresist layer 130, the photoresist layer 130 covering the protective film is etched, and the protective film is removed. photoresist outside the area to form several photolithographic bumps 140 on the buffer layer 120, as shown in FIG. 9B.
  • the shapes of the lithographic protrusions 140 include but are not limited to hemispherical, triangular, cylindrical or rectangular parallelepiped shapes.
  • the lithographic protrusions 140 mainly play a supporting role, and are used for In order to form the elastic connection structure 180 .
  • the first electrode 11 , the piezoelectric layer 12 and the second electrode 13 are deposited on the buffer layer 120 having the plurality of photolithography bumps 140 , so as to form the elastic connection structure 180 on the plurality of photolithography bumps 140 , such as It can be seen from FIG. 9C that one or more elastic connection structures 180 can be formed on the buffer layer 120 according to actual needs; and in order to make the film bulk acoustic resonator more stable, the elastic connection structures 180 and the first electrode 11 or the second electrode 13 is integrally formed, thereby forming the piezoelectric film stack structure 10 with at least one elastic connecting structure 180 .
  • Step S102 providing the substrate 20 with the cavity 30;
  • providing the substrate 20 with the cavity 30 specifically includes: providing a silicon dioxide layer 210, the silicon dioxide layer 210 having a first surface and a second surface arranged oppositely; depositing a first surface on the first surface of the silicon dioxide layer 210 an insulating layer 220, the second insulating layer 230 is deposited on the second surface of the silicon dioxide layer 210; the second insulating layer 230 is etched according to the preset size, so that the cavity 30 is formed in the second insulating layer 230; A metal layer 250 is deposited on the surface of the second insulating layer 230 of the cavity 30 to obtain the substrate 20 having the cavity 30 .
  • a silicon dioxide layer 210 having oppositely disposed first and second surfaces is provided, and a first insulating layer 220 is deposited on the first surface of the silicon dioxide layer 210 as a Substrate, deposit a second insulating layer 230 on the second surface of the silicon dioxide layer 210 as a support layer 500, and use dry or wet etching of the second insulating layer 230 to form a predetermined size in the second insulating layer 230
  • the size of the cavity 30, the preset size is matched with the size of the piezoelectric film stack structure 10, so that the lateral width of the cavity 30 is larger than the lateral width of the piezoelectric film stack structure 10, and the deposition thickness of the second insulating layer 230 is required. It is larger than the longitudinal height of the piezoelectric film stack structure 10 , so that the longitudinal height of the cavity 30 is larger than the longitudinal height of the piezoelectric film stack structure 10 .
  • a metal layer 250 is deposited on the surface of the second insulating layer 230 having the cavity 30 to obtain the substrate 20 having the cavity 30 , as shown in FIG. 10C .
  • step S103 the piezoelectric film stack structure 10 is placed in the cavity 30 of the substrate 20 , and at least one elastic connection structure 180 of the piezoelectric film stack 200 is fixedly connected to the substrate 20 .
  • the piezoelectric film stack structure 10 when the piezoelectric film stack structure 10 is suspended in the cavity 30 of the substrate 20, and when the number of elastic connection structures 180 is two, it is integrally formed with the first electrode 11 and the second electrode 13 , so the first end of the elastic connection structure 180 is integrally formed with the first electrode 11, and the second end of the elastic connection structure 180 is bonded with the metal layer 250 on the substrate 20, so that the first electrode of the piezoelectric template stack structure is formed. 11.
  • the elastic connection structure 180 is elastically and fixedly connected to the substrate 20.
  • the first end of the same elastic connection structure 180 is integrally formed with the second electrode 13, and the second end of the elastic connection structure 180 is bonded to the metal layer 250 on the substrate 20. so that the second electrode 13 of the piezoelectric template stack structure is elastically and fixedly connected to the substrate 20 through the elastic connection structure 180 .
  • Step S104 peeling off the peeling substrate 110 to form a thin film bulk acoustic resonator.
  • the piezoelectric thin film stack structure 10 and the substrate 20 are bonded and connected through the elastic connection structure 180 , the energy loss is reduced through the elastic deformation of the elastic connection structure 180 , and the support can be released at the bonding connection To a certain extent, it can prevent the breakage of the connection, improve the structural stability of the resonator, and to a certain extent, it can also suppress the lateral clutter, avoid energy loss, and improve the filtering performance of the resonator.
  • the manufacturing method of the thin-film bulk acoustic resonator specifically includes the following steps. It should be noted that according to the concept of the present invention and within the scope of the process, the steps can be exchanged or deleted:
  • step S101 a substrate 20 having a cavity 30 is provided, and at least one supporting connector 300 is formed on the substrate 20 .
  • a sacrificial layer 400 is filled in the cavity 30 of the substrate 20, and a supporting material is deposited on the sacrificial layer 400 by CVD or PVD to form a supporting layer 500 with a designed thickness.
  • a patterned photoresist layer 130 is formed on the support layer 500 through a photolithography process, wherein the patterned photoresist layer 130 is in the shape of at least one designed support connector 300 ;
  • the support layer 500 is etched and the photolithography layer 130 is removed to obtain the patterned at least one support connector 300 .
  • dry etching is used to remove the photoresist from the photoresist.
  • the support layer 500 material in the coverage area is etched away with a reactive gas, leaving the support layer 500 material in the photoresist protected area.
  • the photoresist on the surface of the support layer 500 is removed with a glue remover to expose the unetched support material to obtain the at least one support connector 300;
  • the function of the sacrificial layer 400 is mainly to prepare the supporting connector 300 as an intermediate support structure 40. After the supporting connector 300 is prepared and the piezoelectric thin film stack structure 10 is prepared, the sacrificial layer 400 needs to be removed to release the out of the cavity 30 .
  • Step S102 preparing the piezoelectric film stack structure 10 on the at least one supporting connector 300 , so that the piezoelectric film stack structure 10 is fixedly connected to the surface of the substrate 20 through the plurality of supporting connectors 300 to form a thin film bulk acoustic wave resonator ;
  • preparing the piezoelectric thin-film stack structure 10 on the at least one supporting connector 300 includes: sequentially depositing the first layer shown in FIG. 14 on the at least one supporting connector 300 from bottom to top.
  • the two electrodes 13 , the piezoelectric layer and the first electrode 11 form the piezoelectric thin film stack structure 10 on the at least one supporting connector 300 .
  • preparing the piezoelectric thin film stack structure 10 on the at least one supporting connector 300 further includes: providing a peeling substrate 110, and sequentially depositing the first electrode 11 and the piezoelectric layer on the peeling substrate 110 and the second electrode 13 to form the piezoelectric film stack structure 10; place the piezoelectric film stack structure 10 directly above the cavity 30, and connect the second electrode 13 to the at least one support through a bonding process
  • the parts 300 are attached to each other; the peeling substrate 110 is peeled off, so that the piezoelectric film stack structure 10 is formed on the at least one supporting connecting part 300 .
  • the at least one supporting connector 300 is integrally formed with the first electrode 11 or/and the second electrode 13 of the piezoelectric film stack structure 10 .
  • providing the substrate 20 with the cavity 30 specifically includes: providing a silicon dioxide layer 210, the silicon dioxide layer 210 having a first surface and a second surface arranged oppositely; A first insulating layer 220 is deposited on the first surface of the silicon dioxide layer 210, and a second insulating layer 230 is deposited on the second surface of the silicon dioxide layer 210; Etching to form a cavity 30 in the second insulating layer 230 ; depositing a metal layer 250 on the surface of the second insulating layer 230 with the cavity 30 to obtain the substrate 20 with the cavity 30 .
  • a silicon dioxide layer 210 having a first surface and a second surface disposed opposite to each other is provided, a first insulating layer 220 is deposited on the first surface of the silicon dioxide layer 210 as a substrate, and a first insulating layer 220 is deposited on the first surface of the silicon dioxide layer 210.
  • a second insulating layer 230 is deposited on the second surface of the silicon dioxide layer 210 as the support layer 500 , and the second insulating layer 230 is etched by dry or wet etching to form a predetermined size in the second insulating layer 230
  • the size of the cavity 30, the preset size is matched with the size of the piezoelectric film stack structure 10, so that the lateral width of the cavity 30 is greater than the lateral width of the piezoelectric film stack structure 10, and the second insulation
  • the deposition thickness of the layer 230 is greater than the longitudinal height of the piezoelectric thin film stack structure 10 , so that the longitudinal height of the cavity 30 is greater than the longitudinal height of the piezoelectric thin film stack structure 10 .
  • the first electrode 11 or/and the second electrode 13 of the piezoelectric thin film stack structure 10 are fixedly connected to the substrate 20 through the support connecting member 300 , thereby reducing the size of the first electrode 11 or the second electrode 13 Therefore, the anchoring area has a large elastic deformation capacity, which is beneficial to the free vibration of the piezoelectric film stack structure 10 above the cavity 30, thereby reducing the anchor loss and improving the filtering performance of the resonator.
  • Another embodiment of the present application further provides a thin film bulk acoustic resonator manufactured by the manufacturing method of any of the above embodiments.

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Abstract

本申请公开了一种薄膜体声波谐振器及其制造方法和滤波器。所述薄膜体声波谐振器包括：基底和压电薄膜堆叠结构，所述基底具有空腔，所述压电薄膜堆叠结构与所述基底相连且所述压电薄膜堆叠结构的至少部分悬设在所述空腔上方。根据本申请实施例的薄膜体声波谐振器，具有提高的稳定性和可靠性。

Description

薄膜体声波谐振器及其制造方法和滤波器
相关申请的交叉引用
本申请要求申请号为202011567369.2、申请号为202011568972.2和申请号为202011565189.0的中国专利申请的优先权和权益，上述中国专利申请的全部内容在此通过引用并入本申请。
技术领域
本申请涉及微电子器件技术领域，具体涉及声表面波技术领域，尤其涉及一种薄膜体声波谐振器，薄膜体声波谐振器的制造方法和具有薄膜体声波谐振器的滤波器。
背景技术
无线通信相关技术中，人们对于数据传输的要求越来越高，尤其是移动通信领域，随着3G、4G、5G以及未来发展中的6G时代的到来，其网络传输速率和网络容量将大幅提升。然而无线的空间是有限的，随着数据率上升对应的是频谱资源的高利用率以及通信协议的复杂化，相应的对射频系统的各种性能也提出了较高的需求。在射频前端模块中，射频滤波器起到了至关重要的作用，在高频段可选择基于薄膜体声波谐振器的滤波器。但是，相关技术中的薄膜体声波谐振器存在能量损失大、可靠性和稳定性差的问题。
发明内容
本申请是基于发明人对以下事实和问题的发现和认识作出的。
相关技术中，薄膜体声波谐振器的压电薄膜堆叠结构锚接在基底上，锚接通过对薄膜体声波谐振器的电极加宽加粗的方式进行，但发明人经过研究发现锚接处存在锚接能量损失(anchor loss)，一方面声波通过锚接处泄露，另一方面铆接连接处容易发生断裂，压电薄膜堆叠结构的自由振动受限，影响了谐振器的性能。
本申请旨在至少在一定程度上解决相关技术中存在的技术问题之一。
本申请的实施例提供一种稳定性高的薄膜体声波谐振器。
本申请的实施例提供一种具有上述薄膜体声波谐振器的滤波器。
本申请的实施例提供一种薄膜体声波谐振器的制造方法。
本申请的实施例提供一种根据上述制造方法制造的薄膜体声波谐振器。
根据本申请实施例的薄膜体声波谐振器包括：基底和压电薄膜堆叠结构，所述基底具有空腔，所述压电薄膜堆叠结构与所述基底相连且所述压电薄膜堆叠结构的至少部分悬设在所述空腔上方。
在一些实施例中，所述空腔内设置有支撑结构，所述压电薄膜堆叠结构与所述支撑结构不直接接触。
在一些实施例中，所述压电薄膜堆叠结构包括压电层、位于所述压电层之上且与所述压电层的上表面至少部分接触的第一电极和位于所述压电层之下且与所述压电层的下表面至少部分接触的第二电极，所述压电薄膜堆叠结构与所述支撑结构之间具有缝隙部或所述压电薄膜堆叠结构与所述支撑结构之间设置有布拉格反射结构。
在一些实施例中，所述支撑结构的形状为柱形、凸台形、锥形、球形、类球形中的一种或几种。
在一些实施例中，所述缝隙部的高度为1μm-5μm，或，所述布拉格反射结构的上端距离所述压电薄膜堆叠结构的下表面的高度为1μm-5μm。
在一些实施例中，所述支撑结构设置于邻近所述基底与所述压电薄膜堆叠结构之间的键合处的位置。
在一些实施例中，所述支撑结构与所述空腔的底壁一体成型或与所述空腔的底部直接接触。
在一些实施例中，所述支撑结构为多个。
在一些实施例中，所述支撑结构与所述压电薄膜堆叠结构之间设置有布拉格反射结构，所述布拉格反射结构的层数为多层。
在一些实施例中，所述压电薄膜堆叠结构具有至少一个弹性连接结构，所述压电薄膜堆叠结构通过所述至少一个弹性连接结构与所述基底相连。
在一些实施例中，所述压电薄膜堆叠结构还包括：第一电极、压电层、第二电极和至少一个弹性连接结构，所述压电层位于所述第一电极和所述第二电极之间，且所述第一电极和所述第二电极相对设置。
在一些实施例中，所述至少一个弹性连接结构与所述第一电极和所述第二电极中的至少一者一体成型。
在一些实施例中，所述至少一个弹性连接结构的形状为折线形、方波形、波浪形、Ω形或弹簧形。
在一些实施例中，所述基底包括：第一绝缘层、二氧化硅层、第二绝缘层和金属层；所述空腔形成在所述第二绝缘层和所述金属层中，所述第一电极和所述第二电极中的至少一者通过所述至少一个弹性连接结构与所述金属层相连。
在一些实施例中，所述至少一个弹性连接结构由钨、钼、铂白金、钌、铱、钛钨、铝中的至少一者制成。
在一些实施例中，所述薄膜体声波谐振器还包括至少一个支撑连接件，所述压电薄膜堆叠结构通过所述至少一个支撑连接件与所述基底的表面相连。
在一些实施例中，所述压电薄膜堆叠结构包括：第一电极、压电层和第二电极，
所述压电层位于所述第一电极和所述第二电极之间，且所述第一电极和所述第二电极相对设置，所述第一电极和所述第二电极中的至少一者通过所述至少一个支撑连接件与所述基底的表面相连。
在一些实施例中，所述至少一个支撑连接件设置在所述第一电极和所述第二电极中的至少一者与所述基底之间。
在一些实施例中，所述支撑连接件的一端与所述基底相连，所述支撑连接件的另一端伸入所述空腔内且与所述第一电极和所述第二电极中的至少一者连接。
在一些实施例中，所述至少一个支撑连接件与所述第一电极和所述第二电极中的至少一者一体成型。
根据本申请实施例的滤波器包括根据上述任一实施例所述的薄膜体声波谐振器。
根据本申请实施例的薄膜体声波谐振器的制造方法，包括：提供具有空腔的基底；提供压电薄膜堆叠结构；将所述压电薄膜堆叠结构与所述基底相连且使所述压电薄膜堆叠结构的至少部分悬设在所述空腔上方。
在一些实施例中，所述方法还包括在所述空腔内形成支撑结构，其中所述压电薄膜堆叠结构与所述支撑结构不直接接触，
在一些实施例中，其中通过刻蚀在所述基底内形成所述空腔。
在一些实施例中，在所述空腔内形成支撑结构包括：在具有空腔的所述基底上镀层后光刻，其中所述光刻包括涂胶、曝光、和显影。
在一些实施例中，所述压电薄膜堆叠结构通过键合与所述基底相连。
在一些实施例中，提供压电薄膜堆叠结构包括：提供转移基板；以及在所述转移基板上依次沉积第一电极、压电层和第二电极，以形成所述压电薄膜堆叠结构；将所述电薄膜堆叠结构与所述基底键合包括：将所述压电薄膜堆叠结构置于所述空腔的正上方，通过键合工艺使所述第二电极和所述基底的部分上表面相互贴合；以及剥离所述转移基板，以使所述压电薄膜堆叠结构至少部分悬设于所述空腔上方。
在一些实施例中，所述提供压电薄膜堆叠结构包括：在所述基底的空腔中填充牺牲层；在所述牺牲层上自下而上依次沉积所述第二电极、所述压电层和所述第一电极，以形成所述压电薄膜堆叠结构。
在一些实施例中，所述方法还包括提供剥离基板并在所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构；通过至少一个弹性连接结构将所述压电薄膜堆叠结构与所述基底相连；剥离所述剥离基板，以形成所述薄膜体声波谐振器。
在一些实施例中，提供剥离基板并所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构，包括：提供所述剥离基板，并在所述剥离基板上涂布光刻层；对所述光刻层进行蚀刻，以在所述剥离基板上的预设区域内形成多个光刻凸起；在所述剥离基板上依次沉积第一电极、压电层和第二电极，以便在所述多个光刻凸起上形成所述至少一个弹性连接结构，从而得到所述具有至少一个弹性连接结构的压电薄膜堆叠结构。
在一些实施例中，剥离所述剥离基板之后，所述方法还包括：对所述压电薄膜堆叠结构中的多个光刻凸起进行蚀刻，以得到所述薄膜体声波谐振器。
在一些实施例中，所述提供具有空腔的基底，包括：提供二氧化硅层，所述二氧化硅层具有相对设置的第一面和第二面；在所述二氧化硅层的第一面上沉积第一绝缘层，在所述二氧化硅层的第二面上沉积第二绝缘层；按照预设尺寸对所述第二绝缘层进行蚀刻，以在所述第二绝缘层中形成所述空腔；在所述第二绝缘层的表面沉积金属层，以得到所述具有空腔的基底。
在一些实施例中，提供剥离基板并所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构，包括：提供所述剥离基板，在所述剥离基板上沉积缓冲层；在所述缓冲层上制备所述具有至少一个弹性连接结构的压电薄膜堆叠结构。
在一些实施例中，所述光刻凸起为半球状、三角体状、圆柱状或长方体状。
在一些实施例中，所述至少一个弹性连接结构与所述第一电极和所述第二电极中的至少一者一体成型。
在一些实施例中，所述方法还包括：在所述基底上形成至少一个支撑连接件；在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，以通过所述至少一个支撑连接件将所述压电薄膜堆叠结构与所述基底的表面相连。
在一些实施例中，在所述基底上形成至少一个支撑连接件，包括：在所述基底的空腔中填充牺牲层；在所述牺牲层上沉积支撑材料，以形成支撑层；在所述支撑层上形成图形化的光刻层；对所述支撑层进行蚀刻和去除光刻层，以得到所述至少一个支撑连接件。
在一些实施例中，在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，包括：
在所述至少一个支撑连接件上自下而上依次沉积第二电极、压电层和第一电极，以在所述至少一个支撑连接件上形成所述压电薄膜堆叠结构。
在一些实施例中，在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，还包括：
提供剥离基板，在所述剥离基板上依次沉积第一电极、压电层和第二电极，以形成所述压电薄膜堆叠结构；将所述压电薄膜堆叠结构置于所述空腔的正上方，通过键合工艺使所述第二电极与所述至少一个支撑连接件相互贴合；剥离所述剥离基板，以在所述至少一个支撑连接件上形成所述压电薄膜堆叠结构。
在一些实施例中，所述至少一个支撑连接件与所述第一电极和所述第二电极中的至少一者一体成型。
根据本申请实施例的薄膜体声波谐振器，根据上述任一实施例所述的薄膜体声波谐振器制造方法制造。
附图说明
图1为根据本申请第一实施例的薄膜体声波谐振器的示意图。
图2为沿图1中的线A-A的剖面图。
图3为根据本申请第二实施例的薄膜体声波谐振器的剖面图。
图4为根据本申请第三实施例的薄膜体声波谐振器的剖面图。
图5A-5D示出了根据本申请实施例的薄膜体声波谐振器的制造方法的流程。
图6为根据本申请第四实施例的薄膜体声波谐振器的示意图。
图7为根据本申请另一实施例的薄膜体声波谐振器的制造方法的流程图。
图8为图7中步骤S101的具体流程图。
图9A-9C示出了根据本申请第四实施例的薄膜体声波谐振器的压电薄膜堆叠结构的制备流程。
图10A-10C示出了根据本申请第四实施例湿地薄膜体声波谐振器的基底的制备流程。
图11示意性地示出了根据本申请第四实施例的薄膜体声波谐振器的基底和压电薄膜堆叠结构的键合。
图12示意性地示出了剥离基板的剥离。
图13为根据本申请第四实施例的薄膜体声波谐振器的俯视图。
图14为根据本申请第五实施例的薄膜体声波谐振器的剖面图。
图15为根据本申请第六实施例的薄膜体声波谐振器的俯视图。
图16为根据本申请第七实施例的薄膜体声波谐振器的俯视图。
图17为根据本申请又一实施例的薄膜体声波谐振器的制造方法的流程图。
图18A-18D示意性地示出了根据本申请实施例的薄膜体声波谐振器的支撑连接件的制备流程。
图19为根据本申请实施例的薄膜体声波谐振器的基底的示意图。
附图标记：
薄膜体声波谐振器100
压电薄膜堆叠结构10；第一电极11；压电层12；第二电极13；
基底20；镀层21；掩膜22；
空腔30，支撑结构40，球形41，柱形42，锥形43，凸台44，棱柱45，缝隙部50，布拉格反射结构60；
剥离基板110，缓冲层120，光刻层130，光刻凸起140，弹性连接结构180，二氧化硅层210，第一绝缘层220，第二绝缘层230，金属层250；
支撑连接件300，牺牲层400，支撑层500。
具体实施方式
在本申请使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、 “上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征之“上”或之“下”可以包括第一和第二特征直接接触，也可以包括第一和第二特征不是直接接触而是通过它们之间的另外的特征接触。而且，第一特征在第二特征“之上”、“上方”和“上面”包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”包括第一特征在第二特征正下方和斜下方，或仅仅表示第一特征水平高度小于第二特征。下面结合附图，对本申请示例性实施例进行详细说明。在不冲突的情况下，下述的实施例及实施方式中的特征可以相互补充或相互组合。
在本申请使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
需要说明的是，本申请不仅可以应用于移动通信领域，且可以应用于WIFI等其他需要射频的领域。
下面参考附图描述根据本申请实施例的薄膜体声波谐振器。
根据本申请实施例的薄膜体声波谐振器100包括基底20(也可以称为衬底)和压电薄膜堆叠结构10(也可以称为压电三明治结构)。基底20具有空腔30(也可以称为凹槽)，压电薄膜堆叠结构10与基底20相连，压电薄膜堆叠结构10的至少部分悬设在空腔30上方。
根据本申请实施例的薄膜体声波谐振器，可以在一定程度上提高薄膜声波谐振器的稳定性和可靠性。
发明人通过研究认识到，相关技术中，谐振器，尤其是薄膜体声波谐振器，在信号收发系统，例如通信系统运行中，可以被搭建成振荡器或滤波器应用于现代通信系统中。发 明人认为，相对于相关技术中用来构成带通滤波器及微波振荡源的LC振荡器、陶瓷介质谐振器及声表面波(SAW)器件而言，薄膜体声波谐振器除了具有小尺寸、低功耗、低插入损耗以及高工作频率(0.5GHz—10GHz)的优点之外，它的制备工艺可以与CMOS工艺兼容，因此可以与外围电路构成单芯片系统，极大地减小系统的尺寸和功耗。
相关技术中，薄膜体声波谐振器(FABR)主要通过牺牲表面工艺或背部刻蚀工艺来完成，牺牲表面工艺主要利用磷酸硅玻璃或二氧化硅等材料作为填充牺牲层，将压电薄膜堆叠结构沉积在它的表面，在工艺后期将牺牲层去除，从而形成空腔。发明人认为，薄膜体声波谐振器器件的制备工艺相对于其他MEMS器件而言并不复杂，但是背部刻蚀工艺主要是通过在晶圆背面进行体硅刻蚀，从而使得正面形成的压电薄膜堆叠结构的背面处于空腔环境，背面刻蚀工艺的主要问题是需要一层二氧化硅加一层氮化硅薄膜作为压电薄膜堆叠结构的支撑层，使得器件在工艺生产中避免刻蚀液的侵蚀，然而这样的设计容易产生较大的应力，器件容易出现褶皱和破裂，会极大的影响器件的性能，不解决残余应力的问题就无法制备出高性能的FBAR器件，但是如果在空腔内设置支撑结构能一定程度上避免上述问题却又可能由于压电层的声能通过该支撑结构外泄至基底结构，从而导致器件本身的性能下降的问题。
本申请第一方面的实施例提供了一种延迟器件性能下降的薄膜体声波谐振器，通过空腔内设置支撑结构且支撑结构与压电薄膜堆叠结构不直接接触，一方面可避免声能通过支撑结构外泄导致的器件性能下降，另一方面，通过设置支撑结构，在器件运行一段时间后若发生塌陷，支撑结构可一定程度上对压电薄膜堆叠结构进行支撑，避免器件的键合处破损而导致薄膜体声波谐振器性能的严重损毁。可以理解的是，本申请实施例所提出的薄膜体声波谐振器，可以广泛应用于通信器件且在通信系统系统作为滤波器的主要组成器件之一，用于过滤杂波外，该薄膜体声波谐振器也可以用于其他需要滤频的系统中，例如：射频振荡器、滤波器和双工器。
下面参考图1-图5D描述根据本申请第一方面实施例的薄膜体声波谐振器。
如图1和图2所示，图2沿为沿图1中的线A-A的剖面图，根据本申请第一方面实施例的薄膜体声波谐振器100包括基底20和压电薄膜堆叠结构10。基底20具有空腔30，空腔30内设置有支撑结构40，压电薄膜堆叠结构10与支撑结构40不直接接触。换言之，压电薄膜堆叠结构10与支撑结构40间隔开或它们之间设有中间媒介、
在一些实施例中，基底20可选择为绝缘基底20。空腔30设置于绝缘基底20内部，且空腔30的上端与基底20的上表面大致相平。换言之，空腔30形成在绝缘基底20内且空腔30为上端敞开的敞口结构。具体地，基底20可以为SOI基底。本申请的实施例中，基底20可选择常见的硅基底，也可以是玻璃基底、有机材料基底、石英基底、或者其它适用于制备薄膜体声波谐振器(FBAR)的载体的任何基底。
压电薄膜堆叠结构10又称为压电三明治结构，包括自上而下依次堆叠第一电极(也可以称为顶电极)11、压电层12(也可以称为压电晶体、压电薄膜)、第二电极(也可以称 为底电极)13。第一电极11位于压电层12之上且与压电层12的上表面至少部分接触，第二电极13位于压电层12之下且与压电层12的下表面至少部分接触，压电薄膜堆叠结构10至少部分悬设于空腔30的上方。
空腔30可通过干法刻蚀形成，空腔30的大小大致与压电薄膜堆叠结构10相匹配。可选地，沿高度方向(图2中的上下方向)，在图2中的水平面内，空腔30的投影与压电薄膜堆叠结构10的投影至少部分重合，且空腔30的投影稍小于压电薄膜堆叠结构10的投影。在另一些实施例中，空腔30投影稍大于压电薄膜堆叠结构10的投影。理论上，空腔30投影大于压电薄膜堆叠结构10的投影，且压电薄膜堆叠结构10的投影全部位于空腔30投影内，可以最大程度地避免压电能量损失或泄露，但对工艺有一定要求。
发明人的研究表明，空腔30大致为不规则五边形，即，沿高度方向，在图2中的水平面内，空腔30的投影为不规则五边形，压电薄膜堆叠结构10的投影也为不规则五边形。由此，可以更好地抑制横波的反射，避免形成驻波，进而避免影响谐振器的性能。
在另一些实施例中，空腔30大致为不规则四边形或六边形等。换言之，空腔30可以大致为不规则多边形，当然，空腔30可以具有其他任何合适的形状。
图2为沿图1中的线A-A的薄膜体声波谐振器的剖面示意图，压电薄膜堆叠结构10悬设于空腔30内，空腔30的宽度大于压电薄膜堆叠结构10的水平宽度。由此，可以提高对薄膜体声波谐振器的横向杂波的抑制，从而提高谐振器的性能。
具体地，支撑结构40设在空腔30内，支撑结构40的下端与空腔30的底壁相接，所述相接可以是固定连接，例如一体成型或焊接，也可以为非固定连接，例如，支撑结构40仅仅置于空腔30中，通过重力作用与空腔30底壁接触。
需要说明的是，支撑结构40的上端与压电薄膜堆叠结构10不直接接触。具体而言，压电薄膜堆叠结构10与支撑结构40之间可以具有缝隙部50，换言之，压电薄膜堆叠结构10与支撑结构40之间沿高度方向不直接接触。如此设置，在系统运行过程中，压电薄膜堆叠结构10中的声能不会向支撑结构40泄露，从而避免系统出现信号衰减或信号错误。
如图2所示，支撑结构40与压电薄膜堆叠结构10之间设置有缝隙部50，沿高度方向(图2中的上下方向)，缝隙部50的高度可以为1μm-5μm，即支撑结构40的上端距离压电薄膜堆叠结构10的下表面的高度为1μm-5μm。在其他一些实施例中，缝隙部50的高度可以为2μm-3μm。在另外一些实施例中，缝隙部50的高度可以为2.5μm。
在一些实施例中，如图3所示，压电薄膜堆叠结构10与支撑结构40之间沿高度方向设置有布拉格反射结构60。换言之，布拉格反射结构60可以替代至少部分缝隙部50。换言之，支撑结构40的上端设置有布拉格反射结构60。在一些实施例中，布拉格反射结构60与压电薄膜堆叠结构10的下端直接相接。由于布拉格反射结构60的存在，能最大程度上避免压电薄膜堆叠结构10处的能量泄露。在另外一些实施例中，布拉格反射结构60与压电薄膜堆叠结构10的下端可以具有一定距离，因此能量不会泄露，且能保证当压电薄膜堆叠结构10塌陷时，布拉格反射结构60能够起到支撑作用，避免器件的进一步劣化。
可以理解的是，布拉格反射结构60又称为布拉格反射栅，其主要材料是将高声阻抗材料、低声阻抗材料的两种材料交替设置，以此实现声反射避免能量泄露。布拉格反射结构一般有两层以上，层数越多反射效果越好，但相对成本也会增加，因此优选设置为四层，每一层的高度为四分之一的波长周期。如此设置可以更大程度上实现波的反射。
反射层的材料如下：高声阻抗层可替代地包括固相材料，比如金属(铝、铂、钯、钨、钼、铬、钛、钽、或来自元素周期表中IIIA族和/或IVA族的一个或多个的一种或多种元素、或来自IB、IIB、IIIB、IVB、VB、VIB，VIIB和/或VIIIB族中的一个或多个的过渡金属)、陶瓷、玻璃、聚合物等，SiC具有大约427×106N.s/m3的声阻抗，Ir具有大约108×106N.s/m3的声阻抗，并且W具有大约99.9×106N.s/m3的声阻抗。
可选的低声阻抗层322可以包括气相材料等，气相材料可包括以下各项中的一种或多种：氢气、氮气、二氧化碳、一氧化碳、氧气、和/或VIII族惰性气体(例如氦气、氖气、氩气、氪气、氙气)中的一种或多种。气相材料可以为有机材料，比如烃类物质或其具有不同官能团的取代衍生物，气相材料可以为任意前述物质的混合物，空气可以为适当的气相材料或混合物，其具有大约0.0004×106N.s/m3的低声阻抗。
空腔30内设置有支撑结构40，在一些实施例中，支撑结构40可以为绝缘基底20的一部分，支撑结构40经刻蚀绝缘基底20形成。根据本申请实施例的薄膜体声波谐振器，在空腔30内形成支撑结构40，支撑结构40有利于减少薄膜体声波谐振器在键合过程的断裂、损伤，能有效地提高器件生产稳定性，适合批量生产。
如图2所示，在一些实施例中，支撑结构40的形状可以为球形41、柱形42、锥形43、凸台44、棱柱45等。在一些实施例中，支撑结构40的数量可以为一个以上。在另一些实施例中，支撑结构40可以为上述形状结构中的一种或几种的组合。
需要说明的是，柱形41较为容易通过刻蚀方式形成，柱形41可以为圆柱或棱柱，在工艺方面难度小。同样地，其他形状也可通过刻蚀方式形成，但需控制刻蚀液、刻蚀速率等，工艺难度相对较大。通过刻蚀基底20形成支撑结构40可称之为基底20和支撑结构40一体成型。
在另外一些实施例中，球形41不仅可通过刻蚀形成，也可通过其他方式形成，例如通过做出适合尺寸的球形结构后，再放至空腔30中。合适尺寸是指球形41放至空腔30内之后与空腔30的底部31接触，但沿高度方向球形41与压电薄膜堆叠结构10不接触，或圆球的顶部与压电薄膜堆叠结构10的第二电极13不直接接触。也就是说，支撑结构40与基底20并非一体成型的。如此，可以降低工艺的难度。支撑结构40可以与空腔30的底部非固定连接。在其他一些实施例中，支撑结构40与空腔30的底部固定连接，例如焊接或粘结。
如上所述，支撑结构40的材料为一种或几种金属或非金属的组合。具体而言，支撑结构40与基底20一体成型时，其材料与基底20材料相同，如基底20的材料可以采用硅及其氧化物，则支撑结构40的材料也可以为硅及其氧化物。同样地，当基底20的材料为其 他一些非金属或及其氧化物时，支撑结构40的材料可以与其相同。当支撑结构40与基底20并非一体成型时，支撑结构40的材料的可选择范围较宽，例如其可以选择一些形变性能良好的金属材料，如铝。需要说明的是，在同一个薄膜体声波谐振器中，支撑结构40的数量可以为一个或多个，多个支撑结构40的材料也可以的材料和形成工艺可以相同，也可以不相同。
如图2所示，压电薄膜堆叠结构10与基底20通过键合的方式悬设于空腔30上方，支撑结构40的数量为多个。在一些实施例中，支撑结构40设置于邻近基底20与压电薄膜堆叠结构10之间的键合处的位置，即在图2中，靠近空腔30的左侧壁和右侧壁的位置，所述键合处为压电薄膜堆叠结构10的第一电极11和/或第二电极13与基底20的相接之处。如此设置，利于键合处在历经较长时间后发生形变时，支撑结构40能够及时提供支撑作用，避免键合处发生恶性断裂，导致滤波器的性能急速恶化。
图3为根据本申请另一实施例的薄膜体声波谐振器的剖面示意图。支撑结构40的上端为布拉格反射结构60，布拉格反射结构60与压电薄膜堆叠结构10直接接触，通过设置布拉格反射结构60，能更好的降低能量泄露。在另外一些实施例中，布拉格反射结构60与压电薄膜堆叠结构10不直接接触，换言之，布拉格反射结构60与压电薄膜堆叠结构10之间具有一定间隙，能更好的避免能量泄露。
图4示出了根据本申请再一实施例的薄膜体声波谐振器的剖面示意图。支撑结构40为3个，均为柱形，多个支撑结构40均不与压电薄膜堆叠结构10接触。
在一些实施例中，第一电极11和第二电极13的引出部处于同一水平面，便于连接引线测试。在一些实施例中，将第一电极11和第二电极13与绝缘基底20和支撑结构40进行键合后，将薄膜体声波谐振器与其他组件结合组成模组，即可实现滤波。
第一电极11可通过淀积形成，并且光刻形成所需图形，其厚度为100-2000纳米。第一电极11的材料可以为钨、钼、铂白金、钌、铱、钛钨、铝等金属及其合金材料之一或上述至少两种材料的组合。
第二电极13可通过常规沉积工艺形成并图形化，第二电极13的厚度为100-2000纳米。第二电极13的材料可以为钨、钼、铂白金、钌、铱、钛钨、铝等金属或及其合金材料之一或者至少两种材料的组合。
压电层12可通过淀积高C轴取向的压电层12形成，形成方法可选择物理气相沉积、化学气相沉积、反应射频磁控溅射、原子层沉积等方法之一或其结合。需要说明的是，压电层12的图形化，可以使用反应离子刻蚀或者湿法刻蚀工艺刻蚀压电层12，形成将第二电极13引出的通孔。压电层12的材料可以为氮化铝(AlN)、氧化锌(ZnO)、铌酸锂(LiNbO3)、钽酸锂(LiTaO3)之一或者上述至少两种材料的组合。
下面描述根据本申请第二方面实施例的薄膜体声波谐振器。
根据本申请第二方面的实施例的薄膜体声波谐振器，解决了相关技术中的薄膜体声波谐振器在压电薄膜堆叠结构与基底在键合连接处容易发生断裂的问题，提高了谐振器在结 构上的稳定性。
如图6所示，根据本申请实施例的薄膜体声波谐振器具体包括：具有空腔30的基底20和压电薄膜堆叠结构10。
压电薄膜堆叠结构10包括第一电极11、压电层12、第二电极13和至少一个弹性连接结构180。压电层12位于第一电极11和第二电极13之间，且第一电极11和第二电极13大致相对设置；
压电薄膜堆叠结构10设置在基底20的空腔30上，第一电极11和/或第二电极13通过弹性连接结构180与基底20固定连接。具体而言，第一电极11和/或第二电极13与基底20固定连接，所述固定连接可以称为锚接，所述锚接通过具有弹性形变能力的弹性连接结构180实现。
第一电极11的材料可以为钨、钼、铂白金、钌、铱、钛钨、铝之一或者上述至少两种材料的组合。基底20的材料可以为单晶硅、多晶硅、玻璃、石英或蓝宝石之一。
需要说明的是，在本申请的实施例中，弹性连接结构180的数量可以为一个或者多个。压电薄膜堆叠结构10的第一电极11或/和第二电极13通过弹性连接结构180与基底20连接。由于弹性连接结构180本身具有一定的弹性形变能力，在压电薄膜堆叠结构10与基底20的连接处可以吸收/释放支撑应力，一方面减少了锚接损失(anchor loss)，另一方面有效防止连接处发生断裂，提高了谐振器在结构上的稳定性，进而提高产品的稳定性。
另外，弹性连接结构180可以将传播过程中的其他能量储存为弹性势能，并且可以将弹性势能转换成其他形式的能量，能够维持对横向杂波的抑制，更大程度地避免能量损失，提高了谐振器的滤波性能。
在申请的实施例中，在基底20从下到上依次设置有第一绝缘层220、二氧化硅层210、第二绝缘层230和金属层250；在第二绝缘层230和金属层250中设置空腔30，使压电薄膜堆叠结构10设置在空腔30上，第一电极11和/或第二电极13通过弹性连接结构180与金属层250固定连接。在另外一些实施例中，基底20只包含单晶硅。
需要说明的是，在实施例中，弹性连接结构180与第一电极11一体成型，和/或，弹性连接结构180与第二电极13成一体成型。
需要说明的是，在实施例中，弹性连接结构180的形状可以为折线形、方波形、波浪形、Ω形或弹簧形。
需要说明的是，在本实施例中，弹性连接结构180的材料包括钨、钼、铂白金、钌、铱、钛钨、铝之一或者上述至少两种材料的组合。
如图13所示，在实施例中，弹性连接结构180的设置位置可以采用对位设置，即多个弹性连接结构180中，两两彼此相对设置，彼此从力学角度讲，浙连接结构相对稳固。可选地，弹性连接结构180的位置可以任意设定，例如可以仅设定于一角，或者对角设置。需要说明的是，弹性连接结构180在图13中只是俯视示意图，实际上，弹性连接结构180包括但不限于半球状、三角体状、圆柱状或长方体状。图13中示出了未相对设置的两个弹 性连接结构180，根据实际需要可以在任一位置设置一个或者多个弹性连接结构，并且图13中仅示出了第一电极11与弹性连接结构180，第二电极13与弹性连接结构180的设置方式可以与本实施相同或类似。
根据本申请第三方面的实施例的薄膜体声波谐振器，解决了相关技术中的薄膜体声波谐振器的下电极的每一条边均与空腔30的边缘锚接，从而限制了压电薄膜堆叠结构10的自由振动的问题，减少了电学损失，提高了薄膜体声波谐振器的滤波性能。
下面参考附图描述根据本申请第三方面实施例的薄膜体声波谐振器。
相关技术中，提出了一种薄膜体声波谐振器，包括具有空腔的基底和具有上电极、压电层和下电极的压电薄膜堆叠结构，下电极的每一个边与空腔的边缘锚接。但发明人经过研究发现，由于下电极的每一个边均与空腔的边缘锚接，限制了压电薄膜堆叠结构的自由振动，从而影响了薄膜体声波谐振器的滤波性能。
图14为根据本申请第三方面实施例的薄膜体声波谐振器的剖面示意图，如图14所示，薄膜体声波谐振器包括：具有空腔30的基底20、压电薄膜堆叠结构10和至少一个支撑连接件300。
压电薄膜堆叠结构10设置在基底20的空腔30上且通过至少一个支撑连接件300与基底20表面固定连接。具体地，压电薄膜堆叠结构10通过支撑连接件300与基底20表面固定连接，即压电薄膜堆叠结构10通过支撑连接件300与基底20表面锚接，锚接通过支撑连接件300实现。
在一些实施例中，空腔30为不规则的多边形，和/或，压电薄膜堆叠结构10为不规则的多边形，可以在上述多边形的任一边上进行锚接。在另外一些实施例中，可以在上述多边形的任意几条边上进行锚接。不规则的多边形可以是五边形。在一些替代性的实施例中，多边形可以为四边形、六边形、七边形。
需要说明的是，在本实施例中，支撑连接件300可以为一个或多个，压电薄膜堆叠结构10的第一电极11或/和第二电极13通过支撑连接件300与基底20固定连接，与相关技术中通过第一电极11或第二电极13的每条边均与基底20表面连接相比，减小了第一电极11或第二电极13的锚接面积，从而在锚接处具有较大的弹性形变能力，有利于压电薄膜堆叠结构10在空腔30上方的自由振动，进而减少了anchor loss，提高了谐振器的滤波性能。其中，空腔30为有效区域，相关技术中，在空腔30外围的电极有电学损耗，本申请的实施例中国，将电极缩小至空腔30内部，可消除这部分损失。
另地，根据本申请实施例，支撑连接件300具有一定的形变能力，在谐振器工作时，一定程度上可以将压电堆叠结构中泄露的其他形式的能量储存为弹性势能，通过形变将能量再重新转换给压电堆叠结构，一定程度上实现了对横向杂波的抑制，更大程度地降低能量损失，进一步提高了谐振器的性能，提高其Q值。
在本实施例中，压电薄膜堆叠结构10包括：第一电极11、压电层和第二电极13；压电层位于第一电极11和第二电极13之间，且第一电极11和第二电极13相对设置，第一 电极11或/和第二电极13通过支撑连接件300与基底20表面固定连接。第一电极11的材料可以为钨、钼、铂白金、钌、铱、钛钨、铝之一或者上述至少两种材料的组合。第二电极13的材料为钨、钼、铂白金、钌、铱、钛钨、铝之一或者上述至少两种材料的组合。基底20的材料为单晶硅、多晶硅、玻璃、石英或蓝宝石之一。
下面参考附图描述根据本申请又一具体实施例的薄膜体声波谐振器。
在本具体实施例中，图15为与图14相对应的俯视示意图，结合图14和图15可知，支撑连接件300设置在第二电极13与基底20之间，每个支撑连接件300的一端与基底20固定连接，每个支撑连接件300的另一端伸入空腔30内与第二电极13连接。
需要说明的是，支撑连接件300的数量、形状和位置不仅限于附图所示，可以根据谐振器的实际应用场景和谐振器的尺寸进行调整，只要能起到支撑作用且与第二电极13的接触面积小于第二电极13与基底20的接触面积即可。
在本具体实施例中，在基底20从下到上依次设置有第一绝缘层220、二氧化硅层210、第二绝缘层230和金属层250。空腔30设在第二绝缘层230和金属层250中，压电薄膜堆叠结构10设置在空腔30上，第一电极11和/或第二电极13通过支撑连接件300与金属层250固定连接。在另外一些实施例中，基底20只包含单晶硅。其中，本实施例中，第一电极11为上电极层，第二电极13为下电极层，在本实施例中，以下电极层与基底20表面连接为例说明，在实际应用中，可以是上电极层与基底20表面进行固定连接，换言之，可以是上电极层通过支撑连接件300与基底20表面进行固定连接、或下电极层通过支撑连接件300与基底20表面进行固定连接、或上电极层和下电极层均通过支撑连接件300与基底20表面进行固定连接。
需要说明的是，在本具体实施例中，支撑连接件300的材料包括钨、钼、铂白金、钌、铱、钛钨、铝之一或者上述至少两种材料的组合。
在本具体实施例中，支撑连接件300的设置位置可以采用在电极的对边进行设置，从力学角度讲，该种连接结构相对稳固。可选地，支撑连接结构的位置可以任意设定，例如可以仅设定于一边，或者对边设置。
下面参考附图描述根据本申请再一具体实施例的薄膜体声波谐振器。
在本具体实施例中，支撑连接件300与第一电极11或/和第二电极13一体成型，如图16所示，多个支撑连接件300与第二电极13一体成型，图15和图16所示实施例的区别在于：图16是通过在第二电极13上形成具有支撑功能的支撑连接件300，从而达到减少与基底20表面接触面积的目的；图15是通过在第二电极13与基底20表面之间增加具有支撑功能的支撑连接件300，来达到减少与基底20表面接触面积的目的。
本申请的实施例还提出一种具有上述任一实施例所述的薄膜体声波谐振器的滤波器。根据本申请实施例的滤波器，滤波性能和可靠性提高。
下面描述根据本申请实施例的薄膜体声波谐振器的制造方法。
根据本申请实施例的薄膜体声波谐振器的制造方法包括：
提供具有空腔30的基底20；
提供压电薄膜堆叠结构10；
将压电薄膜堆叠结构10与基底20相连且使压电薄膜堆叠结构10的至少部分悬设在所述空腔30上方。
根据本申请实施例的薄膜体声波谐振器的制造方法，通过将压电薄膜堆叠结构的至少部分悬设在基底的空腔上方，从一定程度上减小了对压电薄膜堆叠结构的自由振动造成的影响，从而保证薄膜体声波谐振器的滤波性能。
下面参考附图描述根据本申请第一方面实施例的薄膜体声波谐振器的制造方法。
根据第一方面实施例的薄膜体声波谐振器的制造方法包括：
S01：提供基底，刻蚀基底形成空腔，在空腔内形成支撑结构；
S02：提供压电薄膜堆叠结构，将压电薄膜堆叠结构键合设置于空腔上方，压电薄膜堆叠结构与所述支撑结构不直接接触。
其中，如图5A所示，S01包括提供基底20，刻蚀基底20形成空腔30。
在一些具体实施例中，首先准备绝缘硅基基底20，并将其表面清洗干净。该绝缘硅基基底20从上到下分别是硅、二氧化硅(BOX)、硅基底20。在其他一些实施例中，绝缘硅基基底20的材料也可以选择其他的材料。可以选择干法或者湿法刻蚀绝缘硅基基底20，将刻蚀窗口内的上层的硅部分去除以形成空腔30，即在绝缘硅基基底20内形成空腔30。
湿法刻蚀主要是指传统的刻蚀方法，例如，把硅片浸泡在一定的化学试剂或试剂溶液中，使没有被抗蚀剂掩蔽的那一部分薄膜表面与试剂发生化学反应而被除去。例如，用含有氢氟酸的溶液刻蚀二氧化硅薄膜，用磷酸刻蚀铝薄膜等。这种在液态环境中进行刻蚀的工艺称为“湿法”工艺，其优点是操作简便、对设备要求低、易于实现大批量生产，并且刻蚀的选择性也好。虽然该刻蚀方法化学反应的各向异性较差，横向钻蚀使所得的刻蚀剖面呈圆弧形，但在本实施例中，这种刻蚀方法不仅使图形剖面发生变化，而且当稍有过刻蚀时剖面会产生薄膜上图形的线宽比原抗蚀剂膜上形成的线宽小的结果，对于本实施例有其有利的一面。所述干法刻蚀主要是把硅片表面暴露于空气中产生的等离子体，等离子体通过光刻胶中开出的窗口，与硅片发生物理或化学反应，从而去掉暴露的表面材料，一般包括离子铣刻蚀、等离子刻蚀和反应离子刻蚀三种主要方法，该刻蚀方法具有较高的各向异性特性，能保证图形的精度，尤其对于采用微米级和亚微米量级线宽的超大规模集成电路具有特殊意义。
本实施例的制造方法选用干法刻蚀，能够更好地刻蚀出所需的支撑结构40。如图5B所示，在空腔30内形成支撑结构40，可以先在5A所示的具有空腔30结构的基底20上制备镀层21，在空腔30内的目标位置制备掩膜22，曝光后显影即可制备出如图5C中的支撑结构40。即在具有空腔30结构的基底20上制备镀层21后光刻，光刻包括涂胶、曝光、显影，得到如图所示的支撑结构40。
如图5D所示，提供压电薄膜堆叠结构10并将压电薄膜堆叠结构10键合设置于空腔 30上方，包括：提供剥离基板110(也可以称为转移基板)，在剥离基板110上依次沉积第一电极11、压电晶体和第二电极13，以形成压电薄膜堆叠结构10；将压电薄膜堆叠结构10置于空腔30的正上方，通过键合工艺使第二电极13和/或基底20部分上表面相互贴合；将剥离基板110剥离，使在空腔30上形成压电薄膜堆叠结构10。
在一些具体实施例中，剥离基板110上包括具有一层缓冲层(未示出)，厚度为50-500纳米。本领域技术人员可以理解，本实施例中，基底20为硅基底20。在其他一些实施例中，基底20也可以是玻璃基底20、有机材料基底20、石英基底20、或者其它任何适用于制备薄膜体声波谐振器(FBAR)的载体的基底20。本实施例中，缓冲层用于后续分离剥离基板110和薄膜体声波谐振器(FBAR)，缓冲层的材料可以是二氧化硅，氮化硅，氮氧化硅，磷酸玻璃等材料。根据实际工艺，可以在二氧化硅薄膜中掺杂离子，比如磷，氟，碳，硼等，以便更好地刻蚀。
在一些实施例中，空腔30的深度(图2中空腔在上下方向上的尺寸)与压电薄膜堆叠结构10的整体厚度协调。具体而言，如图2所示，空腔30具有深度H0，压电薄膜堆叠结构10的整体厚度为H1。当压电薄膜堆叠结构10倒扣在空腔30时，如图2所示，空腔30的深度H0要大于压电薄膜堆叠结构10的厚度H1，以便键合后能在压电薄膜堆叠结构10的下表面与空腔30的底壁之间具有一定空间，可用于置放支撑结构40。
需要说明的是，支撑结构40的高度H3要小于压电薄膜堆叠结构10的下表面与空腔30的底部之间的间距H2，H2大致为H0与H1之间的差值，如此设置，使得产品成型时，支撑结构40上端与压电薄膜堆叠结构10的下表面之间具有缝隙部50，且缝隙部50具有一定的高度。在另外一些实施例中，支撑结构40上端与压电薄膜堆叠结构10的下表面之间设置有布拉格反射结构60，布拉格反射结构60可以一定程度上反射声波，避免压电薄膜堆叠结构10处的声能泄露。
在一些实施例中，刻蚀后，空腔30沿高度方向的投影面积S1大于压电薄膜堆叠结构10的投影面积S2，如此设置，压电薄膜堆叠结构10的能量泄露可以达到最低值。
在一些具体的实施例中，使用干法或者湿法刻蚀空腔30内的硅基底20，根据预先设置的图形，刻蚀后，空腔30内将形成多根支撑结构40。且根据不同需求，支撑结构40的数量和位置也不同，可以根据需要设置。
在一些具体的实施例中，第一电极11和第二电极13的上表面在具有空腔30的绝缘硅基基底20上最终处于同一水平面，方便连接引线测试。
在另外一些实施例中，将具有空腔30的绝缘硅基基底20与压电薄膜堆叠结构10键合，键合工艺如下：首先在具有空腔30的绝缘体硅基底20表面沉积一层金属材料，金属材料可以为钨、钼、铂白金、钌、铱、钛钨、铝之一或者至少两种的组合，厚度为100-2000纳米；使用干法或者湿法刻蚀工艺将空腔30内的金属层250去除，保留空腔30外及支撑结构40上的金属层250；将具有空腔30的绝缘体硅基底20的金属层250与压电薄膜堆叠结构10的第一电极11、第二电极13对齐，通过金属键合工艺将两者键合为一个器件。在另 外的实施方式中，也可以在绝缘体硅基底20上预先沉积金属材料，然后再开始具有支撑结构40的空腔30的刻蚀步骤。
相比于相关技术，本申请的实施例具有如下有益效果：
本申请实施例中，通过空腔30内设置支撑结构40且支撑结构40与压电薄膜堆叠结构不相接，一方面可避免声能通过支撑结构40外泄导致的器件性能下降，另一方面，通过设置支撑结构40在器件运行一段时间后若发生塌陷，支撑结构40可一定程度上对压电薄膜堆叠结构进行支撑，避免器件的键合处破损而导致薄膜体声波谐振器性能的严重损毁。
下面参考附图描述根据本申请第二方面实施例的薄膜体声波谐振器的制造方法。
如图7所示，根据本申请实施例的薄膜体声波谐振器的制造方法具体包括以下步骤，需要说明的是在工艺允许范围内，下述步骤的顺序可以调换：
步骤S101，提供剥离基板110，在剥离基板110上制备具有至少一个弹性连接结构180的压电薄膜堆叠结构10。
具体地，在本实施例中，如图8所示，提供剥离基板110，在剥离基板110上制备具有至少一个弹性连接结构180的压电薄膜堆叠结构10，具体的，包括以下步骤：
步骤S201，提供剥离基板110，在剥离基板110上涂布光刻层(也可以称为光刻胶层)130；
步骤S202，对光刻层130进行蚀刻，使在剥离基板110上的预设区域形成若干个光刻凸起140；
步骤S203，在具有若干个光刻凸起140的剥离基板110上依次沉积第一电极11、压电层12和第二电极13，使在若干个光刻凸起140上形成至少一个弹性连接结构180，得到具有至少一个弹性连接结构180的压电薄膜堆叠结构10。
需要说明的是，如图9A所示，提供剥离基板110，在剥离基板110上沉积缓冲层120，缓冲层120主要用于方便从压电薄膜堆叠结构10上进行分离剥离基板110；其中，缓冲层120可以是二氧化硅、氮化硅、氮氧化硅和磷酸剥离等。
通过旋转涂布光刻胶的方式在缓冲层120上形成光刻层130，在光刻层130上的预设区域覆盖保护膜，对覆盖保护膜的光刻层130进行蚀刻，去除保护膜覆盖区域以外的光刻胶，以在缓冲层120上形成若干个光刻凸起140，如图9B所示。其中，对若干个光刻凸起140再进行打磨加工光刻凸起140的形状包括但不限于半球状、三角体状、圆柱状或长方体状，光刻凸起140主要起到支撑作用，用于形成弹性连接结构180。
进一步地，在具有若干个光刻凸起140的缓冲层120上沉积第一电极11、压电层12和第二电极13，以在若干个光刻凸起140上形成弹性连接结构180，如图9C可知，根据实际需要，在缓冲层120上可以形成一个或者多个弹性连接结构180；并且为了使薄膜体声波谐振器更加结构更加稳固，弹性连接结构180与第一电极11或第二电极13一体成型，从而形成带至少一个弹性连接结构180的压电薄膜堆叠结构10。
步骤S102，提供具有空腔30的基底20；
具体地，提供具有空腔30的基底20具体包括：提供二氧化硅层210，二氧化硅层210具有相对设置的第一面和第二面；在二氧化硅层210的第一面沉积第一绝缘层220，在二氧化硅层210的第二面沉积第二绝缘层230；按照预设尺寸对第二绝缘层230进行蚀刻，使在第二绝缘层230中形成空腔30；在具有空腔30的第二绝缘层230表面沉积金属层250，得到具有空腔30的基底20。
需要说明的是，如图10A和10B所示，提供具有相对设置的第一面和第二面的二氧化硅层210，在二氧化硅层210的第一面上沉积第一绝缘层220作为衬底，在二氧化硅层210的第二面上沉积第二绝缘层230作为支撑层500，使用干法或湿法蚀刻第二绝缘层230，使在第二绝缘层230中形成预设尺寸大小的空腔30，预设尺寸与上述压电薄膜堆叠结构10的尺寸相匹配，使空腔30的横向宽度大于压电薄膜堆叠结构10的横向宽度，并且第二绝缘层230的沉积厚度要大于压电薄膜堆叠结构10的纵向高度，从而使空腔30的纵向高度大于压电薄膜堆叠结构10的纵向高度。
最后，在具有空腔30的第二绝缘层230表面沉积金属层250，得到具有空腔30的基底20，如图10C所示。
步骤S103，将压电薄膜堆叠结构10置于基底20的空腔30中，并使压电薄膜堆叠200的至少一个弹性连接结构180与基底20固定连接。
在本申请实施例中，将压电薄膜堆叠结构10悬挂在基底20的空腔30中时，且当弹性连接结构180的数量为2个时，与第一电极11和第二电极13一体成型，因此弹性连接结构180的第一端与第一电极11的一体成型，弹性连接结构180的第二端与基底20上的金属层250进行键合，从而使压电模板堆叠结构的第一电极11通过弹性连接结构180与基底20弹性固定连接，相同的弹性连接结构180的第一端与第二电极13的一体成型，弹性连接结构180的第二端与基底20上的金属层250进行键合，从而使压电模板堆叠结构的第二电极13通过弹性连接结构180与基底20弹性固定连接。
步骤S104，剥离所述剥离基板110，形成薄膜体声波谐振器。
相比于相关技术，本申请实施例具有如下有益效果：
本申请的实施例中，通过弹性连接结构180使压电薄膜堆叠结构10与基底20进行键合连接，通过该弹性连接结构180的弹性形变的减少能量损失，且在键合连接处可以释放支撑应力，一定程度上防止连接处发生断裂，提高了谐振器在结构上的稳定性，一定程度上还可以对横向杂波的抑制作用，避免能量损失，提高了谐振器的滤波性能。
下面参考附图描述根据本申请第三方面实施例的薄膜体声波谐振器的制造方法。
如图17所示，本申请提供的薄膜体声波谐振器的制造方法具体包括以下步骤，需要说明的是根据本发明构思且在工艺允许范围内，所述步骤可以调换或删减：
步骤S101，提供具有空腔30的基底20，在基底20上形成至少一个支撑连接件300。
具体地，如图18A所示，在基底20的空腔30中填充牺牲层400，在所述牺牲层400上通过CVD或PVD沉积支撑材料，形成具有设计厚度的支撑层500.
如图18B所示，通过光刻工艺，在所述支撑层500上形成图形化的光刻层130，其中，所述图形化的光刻层130为设计的至少一个支撑连接件300的形状；对所述支撑层500进行蚀刻和去除光刻层130，得到图形化的所述至少一个支撑连接件300，具体说明的是，如图18C所示，通过干法刻蚀，将光刻胶未覆盖区域的支撑层500材料用反应气体刻蚀掉，留下光刻胶保护区域的支撑层500材料.
进一步地，如图18D所示，刻蚀完成后，用去胶液将支撑层500表面的光刻胶去除，露出未蚀刻掉的支撑材料从而得到所述至少一个支撑连接件300；其中，所述牺牲层400的作用主要是为制备支撑连接件300做中间的支撑结构40，当在所述支撑连接件300制备完成制备压电薄膜堆叠结构10后需要将所述牺牲层400去掉，从而释放出所述空腔30的空间。
步骤S102，在所述至少一个支撑连接件300上制备压电薄膜堆叠结构10，使压电薄膜堆叠结构10通过所述多个支撑连接件300与基底20表面固定连接，形成薄膜体声波谐振器；
在本申请的实施例中，在所述至少一个支撑连接件300上制备压电薄膜堆叠结构10包括：在所述至少一个支撑连接件300上自下而上依次沉积如图14所示的第二电极13、压电层和第一电极11，使在所述至少一个支撑连接件300上形成压电薄膜堆叠结构10。
在本申请的另一个实施例中，在所述至少一个支撑连接件300上制备压电薄膜堆叠结构10还包括：提供剥离基板110，在剥离基板110上依次沉积第一电极11、压电层和第二电极13，形成压电薄膜堆叠结构10；将压电薄膜堆叠结构10置于所述空腔30的正上方，通过键合工艺使所述第二电极13与所述至少一个支撑连接件300相互贴合；剥离所述剥离基板110，使在所述至少一个支撑连接件300上形成压电薄膜堆叠结构10。
在本申请的又一个实施例中，所述至少一个支撑连接件300与压电薄膜堆叠结构10的第一电极11或/和第二电极13一体成型。
在本实施例中，如图19所示，提供具有空腔30的基底20具体包括：提供二氧化硅层210，所述二氧化硅层210具有相对设置的第一面和第二面；在所述二氧化硅层210的第一面沉积第一绝缘层220，在所述二氧化硅层210的第二面沉积第二绝缘层230；按照预设尺寸对所述第二绝缘层230进行蚀刻，使在所述第二绝缘层230中形成空腔30；在带有所述空腔30的第二绝缘层230表面沉积金属层250，得到所述具有空腔30的基底20。
需要说明的是，提供具有相对设置的第一面和第二面的二氧化硅层210，在所述二氧化硅层210的第一面上沉积第一绝缘层220作为衬底，在所述二氧化硅层210的第二面上沉积第二绝缘层230作为支撑层500，使用干法或湿法蚀刻所述第二绝缘层230，使在所述第二绝缘层230中形成预设尺寸大小的空腔30，所述预设尺寸与上述压电薄膜堆叠结构10的尺寸相匹配，使所述空腔30的横向宽度大于压电薄膜堆叠结构10的横向宽度，并且所述第二绝缘层230的沉积厚度要大于压电薄膜堆叠结构10的纵向高度，从而使所述空腔30的纵向高度大于压电薄膜堆叠结构10的纵向高度。
相比于相关技术，本申请的实施例具有如下有益效果：
本申请实施例中，压电薄膜堆叠结构10的第一电极11或/和第二电极13通过所述支撑连接件300与基底20的固定连接，减小了第一电极11或第二电极13的锚接面积，从而在锚接处具有较大的弹性形变能力，有利于压电薄膜堆叠结构10在空腔30上方的自由振动，进而减少了anchor loss，提高了谐振器的滤波性能。
本申请另一方面的实施例还提出一种通过上述任一实施例的制造方法制造的薄膜体声波谐振器。
以上实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对本申请范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请的保护范围应以所附权利要求为准。

Claims (41)

  1. 一种薄膜体声波谐振器，其特征在于，包括：
    基底，所述基底具有空腔；
    压电薄膜堆叠结构，所述压电薄膜堆叠结构与所述基底相连且所述压电薄膜堆叠结构的至少部分悬设在所述空腔上方。
  2. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，所述空腔内设置有支撑结构，所述压电薄膜堆叠结构与所述支撑结构不直接接触。
  3. 根据权利要求2所述的薄膜体声波谐振器，其特征在于，所述压电薄膜堆叠结构包括压电层、位于所述压电层之上且与所述压电层的上表面至少部分接触的第一电极和位于所述压电层之下且与所述压电层的下表面至少部分接触的第二电极，所述压电薄膜堆叠结构与所述支撑结构之间具有缝隙部或所述压电薄膜堆叠结构与所述支撑结构之间设置有布拉格反射结构。
  4. 根据权利要求2或3所述的薄膜体声波谐振器，其特征在于，所述支撑结构的形状为柱形、凸台形、锥形、球形、类球形中的一种或几种。
  5. 根据权利要求3所述的薄膜体声波谐振器，其特征在于，所述缝隙部的高度为1μm-5μm，或，所述布拉格反射结构的上端距离所述压电薄膜堆叠结构的下表面的高度为1μm-5μm。
  6. 根据权利要求2-5中任一项权利要求所述的薄膜体声波谐振器，其特征在于，所述支撑结构设置于邻近所述基底与所述压电薄膜堆叠结构之间的键合处的位置。
  7. 根据权利要求2-6中任一项所述的薄膜体声波谐振器，其特征在于，所述支撑结构与所述空腔的底壁一体成型或与所述空腔的底部直接接触。
  8. 根据权利要求2-7中任一项权利要求所述的薄膜体声波谐振器，其特征在于，所述支撑结构为多个。
  9. 根据权利要求2-8中任一项所述的薄膜体声波谐振器，其特征在于，所述支撑结构与所述压电薄膜堆叠结构之间设置有布拉格反射结构，所述布拉格反射结构的层数为多层。
  10. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，所述压电薄膜堆叠结构具有至少一个弹性连接结构，所述压电薄膜堆叠结构通过所述至少一个弹性连接结构与所述基底相连。
  11. 根据权利要求10所述的薄膜体声波谐振器，其特征在于，所述压电薄膜堆叠结构还包括：第一电极、压电层、第二电极和至少一个弹性连接结构，所述压电层位于所述第一电极和所述第二电极之间，且所述第一电极和所述第二电极相对设置。
  12. 根据权利要求10-11中任一项所述的薄膜体声波谐振器，其特征在于，所述至少一个弹性连接结构与所述第一电极和所述第二电极中的至少一者一体成型。
  13. 根据权利要求10-12中任一项所述的薄膜体声波谐振器，其特征在于，所述至少一个弹性连接结构的形状为折线形、方波形、波浪形、Ω形或弹簧形。
  14. 根据权利要求10-13中任一项所述的薄膜体声波谐振器，其特征在于，所述基底包括：第一绝缘层、二氧化硅层、第二绝缘层和金属层；
    所述空腔形成在所述第二绝缘层和所述金属层中，所述第一电极和所述第二电极中的至少一者通过所述至少一个弹性连接结构与所述金属层相连。
  15. 根据权利要求10-14中任一项所述的薄膜体声波谐振器，其特征在于，所述至少一个弹性连接结构由钨、钼、铂白金、钌、铱、钛钨、铝中的至少一者制成。
  16. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，还包括至少一个支撑连接件，所述压电薄膜堆叠结构通过所述至少一个支撑连接件与所述基底的表面相连。
  17. 根据权利要求16所述的薄膜体声波谐振器，其特征在于，所述压电薄膜堆叠结构包括：第一电极、压电层和第二电极，
    所述压电层位于所述第一电极和所述第二电极之间，且所述第一电极和所述第二电极相对设置，所述第一电极和所述第二电极中的至少一者通过所述至少一个支撑连接件与所述基底的表面相连。
  18. 根据权利要求17所述的薄膜体声波谐振器，其特征在于，所述至少一个支撑连接件设置在所述第一电极和所述第二电极中的至少一者与所述基底之间。
  19. 根据权利要求17或18所述的薄膜体声波谐振器，其特征在于，所述支撑连接件的一端与所述基底相连，所述支撑连接件的另一端伸入所述空腔内且与所述第一电极和所述第二电极中的至少一者连接。
  20. 根据权利要求17-19中任一项所述的薄膜体声波谐振器，其特征在于，所述至少一个支撑连接件与所述第一电极和所述第二电极中的至少一者一体成型。
  21. 一种滤波器，其特征在于，包括根据权利要求1-20中任一项权利要求所述的薄膜体声波谐振器。
  22. 一种薄膜体声波谐振器的制造方法，其特征在于，包括：
    提供具有空腔的基底；
    提供压电薄膜堆叠结构；
    将所述压电薄膜堆叠结构与所述基底相连且使所述压电薄膜堆叠结构的至少部分悬设在所述空腔上方。
  23. 根据权利要求22所述的薄膜体声波谐振器的制造方法，其特征在于，还包括在所述空腔内形成支撑结构，其中所述压电薄膜堆叠结构与所述支撑结构不直接接触，
  24. 根据权利要求23所述的薄膜体声波谐振器的制造方法，其特征在于，其中通过刻蚀在所述基底内形成所述空腔。
  25. 根据权利要求24所述的薄膜体声波谐振器的制造方法，其特征在于，在所述空腔内形成支撑结构包括：在具有空腔的所述基底上镀层后光刻，其中所述光刻包括涂胶、曝光、和显影。
  26. 根据权利要求23-25中任一项所述的薄膜体声波谐振器的制造方法，其特征在于， 所述压电薄膜堆叠结构通过键合与所述基底相连。
  27. 根据权利要求26所述的薄膜体声波谐振器的制造方法，其特征在于，提供压电薄膜堆叠结构包括：提供转移基板；以及在所述转移基板上依次沉积第一电极、压电层和第二电极，以形成所述压电薄膜堆叠结构；
    将所述电薄膜堆叠结构与所述基底键合包括：将所述压电薄膜堆叠结构置于所述空腔的正上方，通过键合工艺使所述第二电极和所述基底的部分上表面相互贴合；以及剥离所述转移基板，以使所述压电薄膜堆叠结构至少部分悬设于所述空腔上方。
  28. 根据权利要求26所述的薄膜体声波谐振器的制造方法，其特征在于，所述提供压电薄膜堆叠结构包括：在所述基底的空腔中填充牺牲层；在所述牺牲层上自下而上依次沉积所述第二电极、所述压电层和所述第一电极，以形成所述压电薄膜堆叠结构。
  29. 根据权利要求22所述的薄膜体声波谐振器的制造方法，其特征在于，还包括：
    提供剥离基板并在所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构；
    通过至少一个弹性连接结构将所述压电薄膜堆叠结构与所述基底相连；
    剥离所述剥离基板，以形成所述薄膜体声波谐振器。
  30. 根据权利要求29所述的薄膜体声波谐振器的制造方法，其特征在于，提供剥离基板并所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构，包括：
    提供所述剥离基板，并在所述剥离基板上涂布光刻层；
    对所述光刻层进行蚀刻，以在所述剥离基板上的预设区域内形成多个光刻凸起；
    在所述剥离基板上依次沉积第一电极、压电层和第二电极，以便在所述多个光刻凸起上形成所述至少一个弹性连接结构，从而得到所述具有至少一个弹性连接结构的压电薄膜堆叠结构。
  31. 根据权利要求30所述的薄膜体声波谐振器的制造方法，其特征在于，剥离所述剥离基板之后，所述方法还包括：
    对所述压电薄膜堆叠结构中的多个光刻凸起进行蚀刻，以得到所述薄膜体声波谐振器。
  32. 根据权利要求30所述的薄膜体声波谐振器的制造方法，其特征在于，所述提供具有空腔的基底，包括：
    提供二氧化硅层，所述二氧化硅层具有相对设置的第一面和第二面；
    在所述二氧化硅层的第一面上沉积第一绝缘层，在所述二氧化硅层的第二面上沉积第二绝缘层；
    按照预设尺寸对所述第二绝缘层进行蚀刻，以在所述第二绝缘层中形成所述空腔；
    在所述第二绝缘层的表面沉积金属层，以得到所述具有空腔的基底。
  33. 根据权利要求29所述的薄膜体声波谐振器的制造方法，其特征在于，提供剥离基板并所述剥离基板上制备具有至少一个弹性连接结构的压电薄膜堆叠结构，包括：
    提供所述剥离基板，在所述剥离基板上沉积缓冲层；
    在所述缓冲层上制备所述具有至少一个弹性连接结构的压电薄膜堆叠结构。
  34. 根据权利要求30所述的薄膜体声波谐振器的制造方法，其特征在于，所述光刻凸起为半球状、三角体状、圆柱状或长方体状。
  35. 根据权利要求30所述的薄膜体声波谐振器的制造方法，其特征在于，所述至少一个弹性连接结构与所述第一电极和所述第二电极中的至少一者一体成型。
  36. 根据权利要求22所述的薄膜体声波谐振器的制造方法，其特征在于，还包括：
    在所述基底上形成至少一个支撑连接件；
    在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，以通过所述至少一个支撑连接件将所述压电薄膜堆叠结构与所述基底的表面相连。
  37. 根据权利要求36所述的薄膜体声波谐振器的制造方法，其特征在于，在所述基底上形成至少一个支撑连接件，包括：
    在所述基底的空腔中填充牺牲层；
    在所述牺牲层上沉积支撑材料，以形成支撑层；
    在所述支撑层上形成图形化的光刻层；
    对所述支撑层进行蚀刻和去除光刻层，以得到所述至少一个支撑连接件。
  38. 根据权利要求36所述的薄膜体声波谐振器的制造方法，其特征在于，在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，包括：
    在所述至少一个支撑连接件上自下而上依次沉积第二电极、压电层和第一电极，以在所述至少一个支撑连接件上形成所述压电薄膜堆叠结构。
  39. 根据权利要求36所述的薄膜体声波谐振器的制造方法，其特征在于，在所述至少一个支撑连接件上制备所述压电薄膜堆叠结构，还包括：
    提供剥离基板，在所述剥离基板上依次沉积第一电极、压电层和第二电极，以形成所述压电薄膜堆叠结构；
    将所述压电薄膜堆叠结构置于所述空腔的正上方，通过键合工艺使所述第二电极与所述至少一个支撑连接件相互贴合；
    剥离所述剥离基板，以在所述至少一个支撑连接件上形成所述压电薄膜堆叠结构。
  40. 根据权利要求38或39所述的薄膜体声波谐振器的制造方法，其特征在于，所述至少一个支撑连接件与所述第一电极和所述第二电极中的至少一者一体成型。
  41. 一种根据权利要求21-40中任一项所述的制造方法制造的薄膜体声波谐振器。
PCT/CN2020/142519 2020-12-25 2020-12-31 薄膜体声波谐振器及其制造方法和滤波器 WO2022134196A1 (zh)

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