WO2020062384A1 - 柔性基底薄膜体声波谐振器及其形成方法 - Google Patents

柔性基底薄膜体声波谐振器及其形成方法 Download PDF

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Publication number
WO2020062384A1
WO2020062384A1 PCT/CN2018/112083 CN2018112083W WO2020062384A1 WO 2020062384 A1 WO2020062384 A1 WO 2020062384A1 CN 2018112083 W CN2018112083 W CN 2018112083W WO 2020062384 A1 WO2020062384 A1 WO 2020062384A1
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layer
film bulk
acoustic
electrode
base film
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PCT/CN2018/112083
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English (en)
French (fr)
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刘伯华
张孟伦
庞慰
杨清瑞
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天津大学
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Publication of WO2020062384A1 publication Critical patent/WO2020062384A1/zh

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    • 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
    • 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
    • H03H3/0072—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks of microelectro-mechanical resonators or networks
    • 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
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02047—Treatment of substrates
    • 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
    • H03H9/02244—Details of microelectro-mechanical resonators
    • H03H9/02393—Post-fabrication trimming of parameters, e.g. resonance frequency, Q factor
    • 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
    • H03H2003/023—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 the resonators or networks being of the membrane type
    • 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
    • H03H2003/027—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 the resonators or networks being of the microelectro-mechanical [MEMS] type
    • 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
    • H03H2009/02165—Tuning
    • H03H2009/02173—Tuning of film bulk acoustic resonators [FBAR]

Definitions

  • the invention relates to the field of semiconductor technology, in particular to a flexible base film bulk acoustic wave resonator and a method for forming the same.
  • piezoelectric bulk acoustic wave (Bulk Acoustic Wave (BAW) devices have become a hot topic at home and abroad. Value, high power capacity, low temperature coefficient, good anti-static impact ability and semiconductor process compatibility, etc., making it meet the requirements of modern communication devices GHz operating frequency level, made by using piezoelectric film longitudinal resonance in the thickness direction Thin-film piezoelectric bulk acoustic wave filters and duplexers have been successfully applied in the field of mobile communications.
  • Q value quality factor
  • the basic structure of a thin film bulk acoustic resonator is a piezoelectric vibrating stack consisting of two layers of electrodes sandwiching a piezoelectric thin film layer.
  • FBAR As a radio frequency device, FBAR requires a radio frequency voltage applied to two electrodes to act as a power source. Under the action of radio frequency voltage, the piezoelectric layer will generate an alternating electric field. Due to the inverse piezoelectric effect, the piezoelectric layer will deform. It is represented by the vibration of phonons, and a sound wave is formed on a macro scale. This sound wave is a bulk acoustic wave inside a piezoelectric body.
  • MEMS micro-electromechanical systems Mechanical systems
  • the filters made by FBAR can be flexible, which has a great impetus for the flexibility of high-frequency circuits.
  • the flexible thin film bulk wave sensor using FBAR as a sensitive element can also be applied in the fields of biology, chemistry, medical diagnosis, and environmental detection.
  • the mainstream international manufacturing method for flexible devices is to combine a thin layer of a silicon substrate and a flexible substrate by a transfer method.
  • the traditional silicon-based thin-film bulk acoustic wave resonator shown in FIG. 1 is often packaged by bonding.
  • the packaging process is as follows: First, a copper pillar is formed around the resonator 013 as a bonding pillar 003 by electroplating. Then, by a bonding method, under a certain pressure and temperature, the cover sheet 001 such as a silicon wafer is bonded to the bonding post 003, and the substrate 011 is used as a part of the package body to form a package structure.
  • the resonance structure 013 is composed of a top electrode 002, a piezoelectric layer 007, and a bottom electrode 009, which are located on the cavity 010 of the substrate.
  • the present invention provides a flexible base film bulk acoustic wave resonator and a method for forming the same, which help to improve the Q value of the device and improve the device performance.
  • One aspect of the present invention provides a method for forming a flexible base film bulk acoustic wave resonator, comprising: providing a sacrificial layer; forming a resonance structure on the sacrificial layer; forming a top acoustic reflection structure on the resonance structure; The sacrificial layer to obtain a stacked structure, and then the stacked structure is transferred to a flexible substrate through a flip process, the stacked structure includes the resonance structure and the top acoustic reflection structure; above the top acoustic reflection structure Form an encapsulation layer.
  • it further comprises forming a bottom acoustic reflection structure, the bottom acoustic reflection structure is located above the flexible substrate and below the resonance structure.
  • the top acoustic reflection structure includes: one low acoustic impedance layer; or, one to two groups of Bragg reflective structures, wherein each group of Bragg reflective structures includes a low acoustic impedance layer and a high acoustic impedance layer.
  • the bottom acoustic reflection structure includes: one layer of low acoustic impedance layer; or, one to two groups of Bragg reflection structures, wherein each group of Bragg reflection structures includes a low acoustic impedance layer and a high acoustic impedance layer.
  • the resonance structure includes a first electrode, a first piezoelectric layer, and a second electrode, which are sequentially arranged from bottom to top; or a first electrode, a first piezoelectric layer, a second electrode, and a second electrode.
  • it further comprises forming a cavity, the cavity is located above the flexible substrate and below the resonance structure.
  • the low acoustic impedance layer includes: epoxy-based resin, polyethylene oxide, silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, and nanoporous hydrogen silsesquioxane.
  • epoxy-based resin polyethylene oxide, silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, and nanoporous hydrogen silsesquioxane.
  • Alkanes, nanoporous mixtures containing methylsilsesquioxane and hydrosilsesquioxane, nanoglass, aerogel, xerogel, spin-on glass, parylene or SiLK Alkanes, nanoporous mixtures containing methylsilsesquioxane and hydrosilsesquioxane, nanoglass, aerogel, xerogel, spin-on glass, parylene or SiLK.
  • the thickness of the low acoustic impedance layer is less than 1 ⁇ m.
  • the high acoustic impedance layer includes: butyl synthetic rubber, polyethylene, neoprene, tungsten, molybdenum, platinum, ruthenium, iridium, tungsten-titanium, tantalum pentoxide, halo oxide, alumina, and silicide. , Niobium carbide, tantalum nitride, titanium carbide, titanium oxide, vanadium carbide, tungsten nitride, tungsten oxide, zirconium carbide, diamond-like or silicon-doped diamond.
  • the thickness of the low acoustic impedance layer is less than 1 ⁇ m
  • the encapsulation layer includes: polyimide or rubber.
  • the thickness of the encapsulation layer is less than 1 ⁇ m.
  • the step of forming an encapsulation layer on the top acoustic reflection structure includes: forming an air gap sacrificial layer on the top acoustic reflection structure; and performing spin coating on the air gap sacrificial layer. Forming the encapsulation layer; removing the air gap sacrificial layer to form an air gap.
  • a flexible substrate thin film bulk acoustic resonator which includes a flexible substrate, a resonant structure, a top acoustic reflection structure, and an encapsulation layer, wherein: the resonant structure is located on the flexible substrate; and the top acoustic A reflective structure is located above the resonant structure; the packaging layer is located above the top acoustic reflection structure.
  • it further includes a bottom acoustic reflection structure, which is located above the flexible substrate and below the resonance structure.
  • the top acoustic reflection structure includes: one low acoustic impedance layer; or, one to two groups of Bragg reflective structures, wherein each group of Bragg reflective structures includes a low acoustic impedance layer and a high acoustic impedance layer.
  • the bottom acoustic reflection structure includes: one layer of low acoustic impedance layer; or, one to two groups of Bragg reflection structures, wherein each group of Bragg reflection structures includes a low acoustic impedance layer and a high acoustic impedance layer.
  • the resonance structure includes a first electrode, a first piezoelectric layer, and a second electrode which are sequentially arranged from bottom to top; or a first electrode, a first piezoelectric layer, and a second electrode , A second piezoelectric layer, and a third electrode; or, a first electrode, a first piezoelectric layer, a second electrode, a decoupling layer, a third electrode, a second piezoelectric layer, and a fourth electrode.
  • it further comprises: a cavity, which is located above the flexible substrate and below the resonance structure.
  • the low acoustic impedance layer includes: epoxy-based resin, polyethylene oxide, silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, and nanoporous hydrogen silsesquioxane.
  • epoxy-based resin polyethylene oxide, silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, and nanoporous hydrogen silsesquioxane.
  • Alkanes, nanoporous mixtures containing methylsilsesquioxane and hydrosilsesquioxane, nanoglass, aerogel, xerogel, spin-on glass, parylene or SiLK Alkanes, nanoporous mixtures containing methylsilsesquioxane and hydrosilsesquioxane, nanoglass, aerogel, xerogel, spin-on glass, parylene or SiLK.
  • the thickness of the low acoustic impedance layer is less than 1 ⁇ m.
  • the high acoustic impedance layer includes: butyl synthetic rubber, polyethylene, neoprene, tungsten, molybdenum, platinum, ruthenium, iridium, tungsten-titanium, tantalum pentoxide, halo oxide, alumina, and silicide. , Niobium carbide, tantalum nitride, titanium carbide, titanium oxide, vanadium carbide, tungsten nitride, tungsten oxide, zirconium carbide, diamond-like or silicon-doped diamond.
  • the thickness of the high acoustic impedance layer is less than 1 ⁇ m.
  • the encapsulation layer includes: polyimide or rubber.
  • the thickness of the encapsulation layer is less than 1 ⁇ m.
  • an air gap is further included, and the air gap is located between the top acoustic reflection structure and the encapsulation layer.
  • a flexible base film bulk acoustic wave resonator is provided.
  • the flexible base film bulk acoustic wave resonator is manufactured by using the method for forming a flexible base film bulk acoustic wave resonator according to any one of the present invention.
  • an encapsulation layer can be formed directly on the surface thereof by spin coating and other similar process conditions, avoiding the formation of a bonding packaging process on the top of the device.
  • the cavity thereby avoiding the problems of the prior art, can effectively guarantee the sealing effect of the device, improve the Q value, and improve the device performance.
  • the top acoustic reflection structure can effectively improve the ability of sound wave reflection, it can confine the sound waves within the resonance structure, avoiding the energy in the resonance structure from leaking into the packaging layer, thereby reducing the energy loss of the resonance structure and making it Q The value increases overall.
  • FIG. 1 is a schematic structural diagram of a thin film piezoelectric bulk acoustic wave resonator in the prior art
  • FIG. 2 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a first embodiment of the present invention
  • FIG. 3 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a second embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a third embodiment of the present invention.
  • FIG. 5 is a schematic structural view of a flexible base film bulk acoustic wave resonator according to a fourth embodiment of the present invention.
  • FIG. 6 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a fifth embodiment of the present invention.
  • FIG. 7 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a sixth embodiment of the present invention.
  • FIG. 8 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a seventh embodiment of the present invention.
  • FIG. 9 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to an eighth embodiment of the present invention.
  • FIG. 10 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a ninth embodiment of the present invention.
  • 11A to 11F are schematic flowcharts of a method for forming a flexible base film bulk acoustic wave resonator according to an embodiment of the present invention.
  • first and second are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of “plurality” is two or more, unless specifically defined otherwise.
  • the terms “installation”, “connected”, “connected”, “fixed” and other terms shall be understood in a broad sense unless otherwise specified and defined, for example, they may be fixed connections or removable connections , Or integrally connected; it can be mechanical or electrical; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements.
  • the specific meanings of the above terms in the present invention can be understood according to specific situations.
  • the "first" or “down” of the second feature may include the first and second features in direct contact, and may also include the first and second features. Not directly, but through another characteristic contact between them.
  • the first feature is “above”, “above”, and “above” the second feature, including that the first feature is directly above and obliquely above the second feature, or merely indicates that the first feature is higher in level than the second feature.
  • the first feature is “below”, “below”, and “below” of the second feature, including the fact that the first feature is directly below and obliquely below the second feature, or merely indicates that the first feature is less horizontal than the second feature.
  • the first aspect of the present invention provides a method for forming a flexible base film bulk acoustic wave resonator.
  • a method for forming a flexible base film bulk acoustic wave resonator includes: providing a sacrificial layer; forming a resonance structure on the sacrificial layer; forming a top acoustic reflection structure on the resonance structure; removing the sacrificial layer to obtain a stack Structure, and then the stacked structure is transferred to the flexible substrate through a flip process.
  • the stacked structure includes a resonance structure and a top acoustic reflection structure; and an encapsulation layer is formed on the top acoustic reflection structure.
  • an encapsulation layer can be directly formed on the surface thereof by spin coating or the like, to avoid The bonding packaging process is used to form a cavity on the top of the device, thereby avoiding the problems of the prior art, effectively ensuring the sealing effect of the device, increasing the Q value, and improving the performance of the device.
  • the top acoustic reflection structure can effectively improve the ability of sound wave reflection, it can confine the sound waves within the resonance structure, avoiding the energy in the resonance structure from leaking into the packaging layer, thereby reducing the energy loss of the resonance structure and making it Q The value increases overall.
  • the material of the sacrificial layer is silicon dioxide (SiO 2 ), phosphosilicate glass (PSG) and the like.
  • SiO 2 silicon dioxide
  • PSG phosphosilicate glass
  • the etching process uses an HF solution, which is etched away, and then the device is transferred down.
  • the sacrificial layer can be removed by wet etching or similar dry etching.
  • the device is placed in a certain proportion of hydrofluoric acid solution. After a period of time, the sacrificial layer is etched and a cavity is formed. The device is suspended above the cavity by the anchor structure. Then use a flexible substrate with adhesiveness to stick to the surface of the device, and then flip it over to form a flexible FBAR device.
  • the flipping transfer method is used to transfer the stacked structure without using a seal or alignment, which can greatly improve the transfer efficiency, reduce costs, and realize large-scale device transfer.
  • the flexible substrate may be polyimide (PI), polydimethylsiloxane (PDMS), polyester resin (PET) polycarbonate (PC), polyethylene naphthalate (PEN), polymer It consists of ether sulfone (PES), polyetherimide (PEI), polyvinyl alcohol (PVA), and various fluoropolymers (FEP).
  • PI polyimide
  • PDMS polydimethylsiloxane
  • PET polyester resin
  • PEN polyethylene naphthalate
  • PES ether sulfone
  • PEI polyetherimide
  • PVA polyvinyl alcohol
  • FEP fluoropolymers
  • the encapsulation layer may be made of similar materials such as polyimide and rubber, and may be the same as or different from the base material.
  • the material properties of the encapsulation layer are required to be flexible, because the entire device is flexible.
  • the acoustic impedance of the packaging layer is preferably a low acoustic impedance material.
  • the thickness of the encapsulation layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the encapsulation layer can be formed by spin coating or spray coating.
  • the spin coating method is: placing the processed device on the base in the cavity of the machine, fixing the device by vacuuming, and then spraying the device.
  • the tube drips the packaging material onto the surface of the device, and rotates by connecting the motor of the base, so that the packaging material is evenly spread on the surface of the device.
  • the thickness of the spin-coated packaging layer can be adjusted. , Uniformity, etc.
  • the spin coating process can save the cost of packaging, and at the same time can avoid the collapse of the cavity caused by the bonding method.
  • the resonance structure may be the simplest sandwich structure, including a first electrode, a first piezoelectric layer, and a second electrode arranged in order from bottom to top.
  • the resonance structure may also be a "3 + 2" sandwich structure, which includes a first electrode, a first piezoelectric layer, a second electrode, a second piezoelectric layer, and a third electrode arranged in order from bottom to top.
  • the resonance structure may also be a sandwich structure stacked in two vertical directions, including a first electrode, a first piezoelectric layer, a second electrode, a decoupling layer, a third electrode, a second piezoelectric layer, Fourth electrode.
  • the electrode material may be metals such as gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), aluminum (Al), and titanium (Ti). And their alloys.
  • the material of the piezoelectric layer can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO 3 ), quartz (Quartz), potassium niobate (KNbO 3 ), or tantalic acid. Materials such as lithium (LiTaO 3 ) and combinations thereof.
  • the top acoustic reflection structure may include: one low acoustic impedance layer or one or two groups of Bragg reflective structures, wherein each group of Bragg reflective structures includes a low acoustic impedance layer and a high acoustic impedance layer.
  • the thickness of the low acoustic impedance layer and the high acoustic impedance layer are both one-quarter or three-quarter the wavelength of the acoustic wave.
  • the top acoustic reflection structure includes only a single low acoustic impedance layer, the device has the advantages of being thin and flexible.
  • the top acoustic reflection structure includes 1 or 2 groups of "low acoustic impedance layer-high acoustic impedance layer" structure, the acoustic wave reflection effect is better.
  • the low acoustic impedance layer is composed of a low acoustic impedance material, which can usually be silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, nano porous hydrogen silsesquioxane, and methyl silsesquioxane.
  • a low acoustic impedance material which can usually be silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methyl silsesquioxane, nano porous hydrogen silsesquioxane, and methyl silsesquioxane.
  • Nanoporous mixtures of methylsilsesquioxane (MSQ) and hydrogen silsesquioxane (HSQ) nanoglasses, aerogels, xerogels, spin-on glass, polyisocyanate Toluene
  • SiLK SiLK is a low dielectric constant material developed by Dow Chemical Company and is currently widely used in integrated circuit production.
  • the thickness of the low acoustic impedance layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the high acoustic impedance layer is composed of a high acoustic resistance material, which can usually be tungsten, molybdenum, platinum, ruthenium, iridium, tungsten titanium, tantalum pentoxide, halo oxide, alumina, silicide, niobium carbide, tantalum nitride, Titanium carbide, titanium oxide, vanadium carbide, tungsten nitride, tungsten oxide, zirconium carbide, diamond-like or silicon-doped diamond.
  • the thickness of the high acoustic impedance layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the low acoustic impedance layer may include an epoxy-based resin or polyethylene.
  • the high acoustic impedance layer may include: butyl synthetic rubber, polyethylene, or neoprene.
  • the encapsulation layer may include polyimide or rubber. It should be noted that the low acoustic impedance layer, the high acoustic impedance layer, and the encapsulation layer may be either pure polymer flexible materials of the foregoing specific materials, or composite flexible materials including the foregoing specific materials.
  • the method for forming the flexible substrate thin film bulk acoustic resonator according to the embodiment of the present invention further includes: forming a bottom acoustic reflection structure, the bottom acoustic reflection structure being located above the flexible substrate and below the resonance structure.
  • the bottom acoustic reflection structure can also effectively improve the ability of sound wave reflection, prevent the energy in the resonator from leaking from the bottom, and confine the sound waves in the resonator, thereby reducing the energy loss of the resonator and increasing its overall Q value.
  • the bottom acoustic reflection structure may include: one layer of low acoustic impedance layer or one or two groups of Bragg reflection structures, wherein each group of Bragg reflection structures includes Low acoustic impedance layer and high acoustic impedance layer.
  • the bottom acoustic reflection structure includes only a single low acoustic impedance layer, the device has the advantages of lightness, thinness, and good flexibility.
  • the bottom acoustic reflection structure contains 1 or 2 groups of "low acoustic impedance layer-high acoustic impedance layer" structure, the acoustic reflection effect is better.
  • the method for forming the flexible substrate thin film bulk acoustic resonator according to the embodiment of the present invention further includes: forming a cavity, the cavity being located above the flexible substrate and below the resonance structure.
  • the acoustic impedance of the air in the cavity is zero, so providing a cavity under the resonant structure can also effectively improve the ability of sound waves to reflect at the interface between the cavity and the bottom of the resonator, and avoid energy leakage in the resonant structure.
  • the acoustic waves are confined within the resonant structure, thereby reducing the energy loss of the resonant structure and increasing its overall Q value.
  • the method for forming a flexible base film bulk acoustic wave resonator according to an embodiment of the present invention further includes: forming an air gap between the top acoustic reflection structure and the packaging layer.
  • the specific method may be: forming an air gap sacrificial layer on the top acoustic reflection structure; forming a packaging layer by spin coating on the air gap sacrificial layer; removing the air gap sacrificial layer to form an air gap.
  • the second aspect of the present invention provides a flexible base film bulk acoustic wave resonator.
  • a flexible substrate thin film bulk acoustic wave resonator includes a flexible substrate, a resonance structure, a top acoustic reflection structure, and an encapsulation layer.
  • the resonance structure is located on the flexible substrate;
  • the top acoustic reflection structure is located on the resonance structure;
  • the encapsulation layer is located on the top acoustic reflection structure.
  • an encapsulation layer can be directly formed on the surface thereof by spin coating or the like, avoiding bonding.
  • the packaging process forms a cavity on the top of the device, thereby avoiding the problems of the prior art, effectively ensuring the sealing effect of the device, increasing the Q value, and improving the device performance.
  • the top acoustic reflection structure can effectively improve the ability of sound wave reflection, it can confine the sound waves within the resonance structure, avoiding the energy in the resonance structure from leaking into the packaging layer, thereby reducing the energy loss of the resonance structure and making it Q The value increases overall.
  • the flexible substrate may be polyimide (PI), polydimethylsiloxane (PDMS), polyester resin (PET) polycarbonate (PC), polyethylene naphthalate (PEN), polymer It consists of ether sulfone (PES), polyetherimide (PEI), polyvinyl alcohol (PVA), and various fluoropolymers (FEP).
  • PI polyimide
  • PDMS polydimethylsiloxane
  • PET polyester resin
  • PEN polyethylene naphthalate
  • PES ether sulfone
  • PEI polyetherimide
  • PVA polyvinyl alcohol
  • FEP fluoropolymers
  • the encapsulation layer may be made of similar materials such as polyimide and rubber, and may be the same as or different from the base material.
  • the material properties of the encapsulation layer are required to be flexible, because the entire device is flexible.
  • the acoustic impedance of the packaging layer is preferably a low acoustic impedance material.
  • the thickness of the encapsulation layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the resonance structure may be the simplest sandwich structure, including a first electrode, a first piezoelectric layer, and a second electrode arranged in order from bottom to top.
  • the resonance structure may also be a "3 + 2" sandwich structure, which includes a first electrode, a first piezoelectric layer, a second electrode, a second piezoelectric layer, and a third electrode arranged in order from bottom to top.
  • the resonant structure can also be two sandwich structures stacked vertically, including a first electrode, a first piezoelectric layer, a second electrode, a decoupling layer, a third electrode, a second piezoelectric layer, a first electrode Four electrodes.
  • the electrode material may be metals such as gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), aluminum (Al), and titanium (Ti). And their alloys.
  • the material of the piezoelectric layer can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO 3 ), quartz (Quartz), potassium niobate (KNbO 3 ), or tantalic acid. Materials such as lithium (LiTaO 3 ) and combinations thereof.
  • the top acoustic reflection structure may include: one layer of low acoustic impedance layer; or, one or two groups of Bragg reflection structures, where each group of Bragg reflection structures includes low acoustic impedance layer and high acoustic impedance layer.
  • each group of Bragg reflection structures includes low acoustic impedance layer and high acoustic impedance layer.
  • the top acoustic reflection structure includes only a single low acoustic impedance layer, the device has the advantages of being thin and flexible.
  • the top acoustic reflection structure includes 1 or 2 groups of "low acoustic impedance layer-high acoustic impedance layer" structure, the acoustic wave reflection effect is better.
  • the low acoustic impedance layer is composed of a low acoustic impedance material, which may be silicon oxide, aluminum, carbon-doped silicon oxide, nanoporous methylsilsesquioxane, nanoporous hydrogen silsesquioxane, containing formazan Nanoporous mixtures of methylsilsesquioxane (MSQ) and hydrogen silsesquioxane (HSQ), nanoglasses, aerogels, xerogels, spin-on glass, polymer P-xylene, SiLK or benzocyclobutene.
  • the thickness of the low acoustic impedance layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the high acoustic impedance layer is composed of a high acoustic resistance material, which can be tungsten, molybdenum, platinum, ruthenium, iridium, tungsten titanium, tantalum pentoxide, halo oxide, alumina, silicide, niobium carbide, tantalum nitride, titanium carbide, Titanium oxide, vanadium carbide, tungsten nitride, tungsten oxide, zirconium carbide, diamond-like or silicon-doped diamond.
  • the thickness of the high acoustic impedance layer is less than 1 ⁇ m. Since it is a thin film, the flexibility of the device is increased.
  • the low acoustic impedance layer may include an epoxy-based resin or polyethylene.
  • the high acoustic impedance layer may include: butyl synthetic rubber, polyethylene, or neoprene.
  • the encapsulation layer may include polyimide or rubber. It should be noted that the low acoustic impedance layer, the high acoustic impedance layer, and the encapsulation layer may be either pure polymer flexible materials of the foregoing specific materials, or composite flexible materials including the foregoing specific materials.
  • the flexible base film bulk acoustic wave resonator according to the embodiment of the present invention further includes a bottom acoustic reflection structure, which is located above the flexible substrate and below the resonance structure.
  • the bottom acoustic reflection structure can also effectively improve the ability of sound wave reflection, prevent the energy in the resonator from leaking into the flexible substrate, and confine the sound wave within the resonator, thereby reducing the energy loss of the resonator and increasing its overall Q value.
  • the bottom acoustic reflection structure may include: one low acoustic impedance layer or one or two groups of Bragg reflective structures, wherein each group of Bragg reflective structures includes low acoustic impedance Layer and high acoustic impedance layer.
  • the bottom acoustic reflection structure includes only a single low acoustic impedance layer, the device has the advantages of lightness, thinness, and good flexibility.
  • the bottom acoustic reflection structure includes 1 or 2 groups of "low acoustic impedance layer-high acoustic impedance layer" structure, the acoustic reflection effect is better.
  • the flexible base film bulk acoustic wave resonator according to the embodiment of the present invention further includes a cavity.
  • the cavity is above the flexible substrate and below the resonant structure.
  • the acoustic impedance of the air in the cavity is zero, so providing a cavity under the resonant structure can also effectively improve the ability of sound waves to reflect at the interface between the cavity and the bottom of the resonator, and avoid energy leakage in the resonant structure.
  • the acoustic waves are confined within the resonant structure, thereby reducing the energy loss of the resonant structure and increasing its overall Q value.
  • the flexible base film bulk acoustic wave resonator according to the embodiment of the present invention further includes an air gap, and the air gap is located between the top acoustic reflection structure and the packaging layer.
  • FIG. 2 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a first embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 200 includes a flexible substrate 219; a cavity 217; a resonant structure 214, which includes a bottom electrode 215, a piezoelectric layer 213, and a top electrode 211; and a top acoustic reflection structure 210 It includes two sets of Bragg reflection structures, namely low acoustic impedance layers 209 and 205 and high acoustic impedance layers 207 and 203; and a packaging layer 201; wherein the cavity 217 serves the purpose of acoustic isolation of the resonance structure 214.
  • the bottom electrode, piezoelectric layer, top electrode, and cavity overlap in the vertical direction are the effective area of the resonator.
  • an alternating voltage signal of a certain frequency is applied between the upper and lower electrodes of the resonator, due to The inverse piezoelectric effect of piezoelectric materials will generate sound waves propagating vertically between the upper and lower electrodes in the effective area. The sound waves will be reflected back and forth between the interface between the bottom electrode and the air and the Bragg reflection structure on the top electrode. And generate resonance at a certain frequency.
  • the manufacturing process of the flexible FBAR 200 includes: firstly processing a FBAR with a top acoustic reflection structure on the top of a single crystal silicon substrate, and its manufacturing sequence is: etching on a silicon substrate (about 400 ⁇ m thick) to form a cavity and depositing Layer of sacrificial material, smooth its surface by chemical mechanical planarization to form a sacrificial layer (about 3.4 ⁇ m thick); deposit a resonant structure; deposit a top acoustic reflection structure; then remove the sacrificial layer; and finally transfer it through a stamp under micromanipulation Method, the FBAR device with a top acoustic reflection structure prepared on a silicon substrate is stacked and placed on a flexible substrate according to an alignment mark, thereby forming a flexible FBAR device, and then on the surface of the top acoustic reflection structure
  • the encapsulation layer is formed by a similar process such as spin coating.
  • the flexible base film bulk acoustic wave resonator shown in FIG. 2 and the manufacturing method thereof can significantly improve the Q value after the resonator is packaged, because the top acoustic reflection structure can effectively improve the ability of sound wave reflection and avoid the energy in the resonator. Leaked into the packaging layer, confining the acoustic wave to the resonator, thereby reducing the energy loss of the resonator and increasing its Q value as a whole.
  • the device due to the existence of the top acoustic reflection structure, the device can directly form an encapsulation layer on the surface by spin coating and other similar process conditions, which can effectively solve the problem of flexible device packaging, and at the same time, make the device packaging process easier and lower. It reduces the cost of device packaging, and can effectively reduce the air tightness requirements in flexible packaging.
  • FIG. 3 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a second embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 300 includes a flexible substrate 323; a bottom acoustic reflection structure 320, which includes a bottom first high acoustic impedance layer 321, a bottom first low acoustic impedance layer 319, and a bottom first Two high acoustic impedance layers 317 and a second low acoustic impedance layer 315 at the bottom; a resonant structure 314 including: a bottom electrode 313, a piezoelectric layer 312, and a top electrode 311; and a top acoustic reflection structure 304 including a first high acoustic impedance at the top A layer 303, a top first low acoustic impedance layer 305, a top second high acoustic impedance
  • the acoustic mirror structure composed of the bottom acoustic reflection structure and the top acoustic reflection structure can play a role of limiting the sound waves.
  • the acoustic mirror structure can play an acoustic isolation function between the resonance structure and the flexible substrate and the packaging layer, thereby preventing sound wave energy from leaking into the flexible substrate or the packaging layer, avoiding acoustic losses, and thereby increasing the Q value of the device.
  • the manufacturing process of the flexible FBAR 300 includes: firstly processing an FBAR with a Bragg reflection structure on a single crystal silicon substrate, the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; secondly, depositing a bottom acoustic reflection structure 320; deposit the resonant structure 314; deposit the top acoustic reflection structure 304; then remove the sacrificial layer; then transfer the stacked structure onto the flexible substrate 323, and finally form an encapsulation layer 301 on top of the device.
  • the substrate can be any flexible material and can be freely
  • the choice of flexible materials with lower cost reduces the cost of device fabrication, and can expand the scope of device applications, enabling it to adapt to more complex environments;
  • the Bragg reflection structure formed above and below the resonant structure 314 makes the device resistant to the outside world
  • the ability to change the environment is enhanced, such as the effect of humidity and particle adsorption on the frequency of the device, and the packaging layer can be directly formed on the surface by similar processes such as spin coating, which greatly reduces the process steps of device packaging and makes it more efficient in packaging.
  • FIG. 4 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a third embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 400 includes a flexible substrate 415; a bottom acoustic reflection structure 412, which includes a first high acoustic impedance layer 413 at the bottom and a first low acoustic impedance layer 411 at the bottom; a resonant structure 410, which includes: a bottom electrode 407, a piezoelectric layer 406, and a top electrode 405; a top acoustic reflection structure 404, which includes a top first high acoustic impedance layer 402, a top first low acoustic impedance layer 403, and an encapsulation layer 401.
  • the manufacturing process of the flexible FBAR 400 includes: firstly processing a FBAR with a Bragg reflection structure on a single crystal silicon substrate, the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; secondly, depositing a bottom acoustic reflection structure 412; deposit the resonant structure 410; deposit the top acoustic reflection structure 404; then remove the sacrificial layer; then transfer the stacked structure onto the flexible substrate 415, and finally form an encapsulation layer 401 on the top of the device.
  • the number of material groups of the bottom acoustic reflection structure and the top acoustic reflection structure is set to one, which can effectively increase the flexibility of the device and enable it to be applied in more complicated environments.
  • a flexible thin film bulk acoustic wave resonator (FBAR) 500 includes a flexible substrate 513; a bottom acoustic reflection structure 511, which includes only a single low acoustic impedance layer; and a resonant structure 510, which includes: a bottom electrode 509, The electrical layer 507 and the top electrode 505; the top acoustic reflection structure 503, which includes only a single low acoustic impedance layer; and a packaging layer 501.
  • FBAR flexible thin film bulk acoustic wave resonator
  • the manufacturing process of the flexible FBAR 500 includes: firstly processing a FBAR with a Bragg reflection structure on a single crystal silicon substrate, the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; secondly, depositing a bottom acoustic reflection structure 511; deposit the resonance structure 510; deposit the top acoustic reflection structure 503; then remove the sacrificial layer; then transfer the stacked structure to the flexible substrate 513, and finally form an encapsulation layer 501 on the top of the device.
  • the number of layers constituting the Bragg reflection structure is too much, the device is easily broken during the bending process, which is not conducive to its flexibility. Therefore, the number of Bragg reflective structures at the bottom and top is only set to a single layer, which can effectively increase the flexibility of the device and enable it to be used in more complex environments.
  • FIG. 6 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a fifth embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 600 includes a flexible substrate 617; a resonant structure 616, which includes: a bottom electrode 615, a piezoelectric layer 613, and a top electrode 611; and a top acoustic reflection structure 610, which includes A top first high acoustic impedance layer 603, a top first low acoustic impedance layer 605, a top second high acoustic impedance layer 607, and a top second low acoustic impedance layer 609; and a packaging layer 601.
  • the manufacturing process of the flexible FBAR 600 includes: firstly processing an FBAR with a Bragg reflection structure on a single crystal silicon substrate, the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; depositing a resonant structure 616; deposition The top acoustic reflection structure 610; then the sacrificial layer is removed; finally, by the method of stamp transfer, under a micro operation, the FBAR with the top acoustic reflection structure prepared on the silicon substrate is lifted and placed directly into the flexibility On the substrate 617, a flexible FBAR is formed, and then a packaging layer 601 is formed on the surface of the device by a similar process such as spin coating.
  • the material of the flexible substrate is a similar material such as polyimide (PI) or poly-para-xylene, where the acoustic impedance is close to zero, and the thickness of the flexible substrate ranges from 10 ⁇ m to 400 ⁇ m.
  • PI polyimide
  • T transmission coefficient
  • the connection between the device and the flexible substrate and the packaging layer is more It is firm and does not need to process the cavity on the substrate, which can simplify the process steps; there is no cavity on the flexible substrate, and the device does not need to be aligned during the transfer process, which greatly improves the efficiency of device transfer; the existence of the Bragg reflective structure makes the device
  • the encapsulation layer can be directly formed on the surface by similar process conditions such as spin coating, which can effectively solve the problem of flexible device packaging, while making the device packaging process easier, reducing the cost of device packaging, and effectively reducing flexibility
  • the requirements for airtightness in the package make the stability of the device package improve and increase the reliability of the device.
  • FIG. 7 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a sixth embodiment of the present invention.
  • a flexible stacked thin film bulk acoustic resonator (FBAR) 700 includes: a flexible substrate 723; a bottom acoustic reflection structure 720, which includes a bottom first high acoustic impedance layer 721 and a bottom first low acoustic impedance layer 718 A first electrode 715, a first piezoelectric layer 713, a second electrode 711, a second piezoelectric layer 709, and a third electrode 707; a top acoustic reflection structure 702 including a top first high acoustic impedance layer 703 and a top first Low acoustic impedance layer 705.
  • the manufacturing process of the flexible stacked FBAR 700 includes firstly processing a stacked FBAR with a Bragg reflection structure on a single crystal silicon substrate.
  • the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; depositing the bottom Acoustic reflection structure; deposit first electrode, first piezoelectric layer, second electrode, second piezoelectric layer, third electrode; deposit top acoustic reflection structure; then remove sacrificial layer; then transfer stacked structure to flexible substrate 723 Finally, a packaging layer 701 is formed on top of the device.
  • the flexible stacked thin film bulk acoustic resonator can be simply packaged.
  • the flexible coupling resonant filter 800 includes: a flexible substrate 823; a bottom acoustic reflection structure 820, which includes a first high acoustic impedance layer 821 at the bottom and a first low acoustic impedance layer 819 at the bottom; and a first resonator 812 , Which includes a first bottom electrode 817, a first piezoelectric layer 815, and a first top electrode 813; a decoupling layer 811; and a second resonator 804, which includes a second bottom electrode 809, a second piezoelectric layer 807, and a second The top electrode 805; the top acoustic reflection structure 802, which includes a top first high acoustic impedance layer 801 and a top first low acoustic impedance layer 803; and an
  • the manufacturing process of the flexible stacked FBAR 800 includes firstly processing a coupled resonant filter with a Bragg reflection structure on a single crystal silicon substrate.
  • the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; deposition Bottom acoustic reflection structure; deposit first resonator; deposit decoupling layer; deposit second resonator; deposit top acoustic reflection structure; then remove sacrificial layer; then transfer the stacked structure to flexible substrate 823 and finally form on top of the device Encapsulation layer 801.
  • the flexible stacked thin film bulk acoustic resonator can be simply packaged.
  • FIG. 9 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to an eighth embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 900 includes a flexible substrate 917; a resonant structure 916, which includes: a bottom electrode 915, a piezoelectric layer 913, and a top electrode 911; and a packaging layer 919.
  • the packaging layer 919 preferably uses a flexible low acoustic impedance material, such as PI, PET, and the like. In this way, the packaging layer 919 not only plays a role of mechanical packaging, but also plays a role of sound wave sealing.
  • the manufacturing process of the flexible FBAR900 includes: firstly processing the FBAR on a single crystal silicon substrate, the manufacturing sequence is: forming a cavity on the silicon substrate and depositing a sacrificial layer; depositing a resonant structure 916; then removing the sacrificial layer; then The stacked structure is transferred to the flexible substrate 917, and finally, an encapsulation layer 919 is formed on the top of the device.
  • the materials of the flexible substrate and the encapsulation layer are selected from similar materials such as polyimide (PI) or polyparaxylene, which have acoustic impedances as close to zero as possible.
  • the materials of the flexible substrate and the encapsulation layer can be similar. Same or different.
  • a material with an acoustic impedance as close to zero as possible is used for packaging by spin coating, which can realize that the device can encapsulate the acoustic wave while packaging.
  • the device can not only resist the impact of changes in the external environment on its performance, but also ensure the Q value of the device.
  • FIG. 10 is a schematic structural diagram of a flexible base film bulk acoustic wave resonator according to a ninth embodiment of the present invention.
  • a flexible thin film bulk acoustic resonator (FBAR) 1000 includes a flexible substrate 1017; a resonant structure 1016 including: a bottom electrode 1015, a piezoelectric layer 1013, and a top electrode 1011; an encapsulation layer 1019; and a top electrode 1010 ⁇ And the air gap 1010 between the packaging layer.
  • the air gap between the top electrode and the encapsulation layer can improve both the reflectivity of the acoustic wave and the bending performance.
  • the existence of the air gap can effectively improve the reflectivity of the sound waves reflected back into the resonator; meanwhile, the existence of the air gap makes the device easier to bend, and can improve the bending performance of the device, making The device can adapt to more complex environments.
  • the air gap proposed in this embodiment is also applied to any one of the embodiments of the present invention, but it is not shown in the drawings of other embodiments.
  • the air gap is located at the top of the acoustic reflection structure and Between encapsulation layers.
  • the processing method of the air gap structure is: after transferring the resonance structure (ie, the stacked structure) to a flexible substrate, a thin film deposition process such as PECVD, CVD, or PVD is used to deposit an air gap sacrificial layer on the top acoustic reflection layer.
  • a thin film deposition process such as PECVD, CVD, or PVD is used to deposit an air gap sacrificial layer on the top acoustic reflection layer.
  • the material of the air-gap sacrificial layer can be silicon dioxide (SiO 2 ) or phosphosilicate glass (PSG) and the like, and then an encapsulation layer is formed by a spin coating process on the air-gap sacrificial layer, and finally a wet method Etching (using a hydrofluoric acid solution) or dry etching and other similar process conditions remove the air gap sacrificial layer to form an air gap structure.
  • FIGS. 11A to 11F are schematic flowcharts of a method for forming a flexible base film bulk acoustic wave resonator according to an embodiment of the present invention.
  • the specific steps of processing a complete flexible substrate film bulk acoustic resonator are as follows:
  • a cavity is formed on a silicon substrate by a dry etching process, and a sacrificial material 1001 such as Phospho-Silicate-Glass (PSG) is filled, and the surface of the film is made flat and smooth by chemical mechanical planarization. , As shown in Figure 11A.
  • a sacrificial material 1001 such as Phospho-Silicate-Glass (PSG) is filled, and the surface of the film is made flat and smooth by chemical mechanical planarization.
  • PECVD plasma enhanced chemical vapor deposition
  • PVD physical vapor deposition
  • CVD chemical vapor deposition
  • CVD chemical vapor deposition
  • CVD chemical vapor deposition
  • a similar thin film deposition process deposits the bottom high acoustic impedance layer 1105 and the bottom low acoustic impedance layer 1107 of the bottom acoustic reflection structure 1106, as shown in FIG. 11B.
  • a bottom electrode 1109 is deposited on the bottom low acoustic impedance layer 1107 of the bottom acoustic reflection structure 1106 by a thin film deposition process, and then a bottom electrode pattern is formed by a process of photolithography, etching, and debonding, and then the same process is used to deposit the bottom electrode.
  • the piezoelectric layer 1111 finally forms a top electrode 1113 on the piezoelectric layer, as shown in FIG. 11C.
  • top low acoustic impedance layer 1115 and the top high acoustic impedance layer 1117 of the top acoustic reflection structure 1116 are deposited on the top electrode of the resonant structure 1110 by a thin film deposition process, as shown in FIG. 11D.
  • a material such as polyimide (PI), which has an acoustic impedance as close to zero as possible and is flexible, can be encapsulated by a similar process such as spin coating.
  • PI polyimide
  • the method for manufacturing a flexible base film bulk acoustic wave resonator according to the embodiment of the present invention can make the device not need to be stamped and aligned during the transfer process, thereby making the transfer process easier and simpler, and further improving device transfer effectiveness.
  • the sealing effect is good, and the Q value of the device is high.
  • the invention also provides a flexible base film bulk acoustic wave resonator.
  • the flexible base film bulk acoustic wave resonator is manufactured by using any of the methods for forming a flexible base film bulk acoustic wave resonator according to an embodiment of the present invention.

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Abstract

一种柔性基底薄膜体声波谐振器及其形成方法，有助于提高器件的Q值，改善器件性能。其中，柔性基底薄膜体声波谐振器的形成方法，包括：提供牺牲层（1101）；在牺牲层（1101）之上形成谐振结构（214）；在谐振结构（214）之上形成顶部声反射结构（210）；去除牺牲层（1101），从而得到堆叠结构，然后将堆叠结构通过翻转工艺转移到柔性基底（219）上，堆叠结构包括谐振结构（214）和顶部声反射结构（210）；在顶部声反射结构（210）之上形成封装层（201）。

Description

柔性基底薄膜体声波谐振器及其形成方法 技术领域
本发明涉及半导体技术领域，特别地涉及一种柔性基底薄膜体声波谐振器及其形成方法。
背景技术
随着微机械制造技术的发展，压电体声波(Bulk Acoustic Wave，简称BAW)器件成为国内外研究的热点，由于其具有体积小、工作频率高、插入损耗低、带外抑制大、高Q值、大功率容量、低温度系数以及良好的抗静电冲击能力和半导体工艺兼容性等优点，使其符合现代通讯器件GHz工作频率级的要求，利用压电薄膜在厚度方向的纵向谐振所制成的薄膜压电体声波滤波器、双工器产品已经成功应用于移动通信领域。同时，由于薄膜体声波谐振器的工作频率高、品质因数(Q值)高等优点，使其在传感器领域中的应用也被广泛关注。
薄膜体声波谐振器(Film Bulk Acoustic Resonator，简称FABR)的基本结构是由两层电极夹着一层压电薄膜层的压电震荡堆。作为射频器件，FBAR需要一个施加在两个电极上的射频电压来充当功率源，在射频电压的作用下，压电层会产生交变电场，由于逆压电效应，压电层产生形变，微观上表现为声子的震动，宏观上形成声波，此声波为压电体内部的体声波，通过这样一个过程，电能转化为机械能。体声波会在震荡堆的上下电极之间来回反射。根据驻波形成的条件，当声波在振荡堆中传播的距离是半波长或半波长的奇数倍时便会产生驻波振荡，由于正压电效应，来回振荡的体声波又会激励起射频电信号，又完成机械能到电能的转换，形成电信号的谐振。
与此同时，柔性材料正在半导体器件制造中扮演着越来越重要的 作用，一般选择柔性的基底材料代替传统刚性材料。传统的硅基材料具有机械脆性，不足以维持较大的形变以及瞬时的冲击，并且也较难运用于诸如表面弯曲的触觉传感探测等领域，故而硅基的微机电系统(Micro-Electro-Mechanical System，简称MEMS)器件有着自身的局限性，而柔性材料有着诸如可弯曲、耐冲击、成本低等优良的特性，将其运用于MEMS器件可在传感领域有广阔的应用前景。对于薄膜体声波谐振器来说，也可以制成柔性，同样会有着巨大的应用潜力，可以将FBAR制备的滤波器实现柔性化，其对于实现高频电路的柔性化有着巨大的推动意义。同时以FBAR为敏感原件的柔性薄膜体波传感器也可以应用于生物、化学、医疗诊断、环境检测等领域中。当前，对于柔性器件的国际主流制作方法为将一层很薄的硅基底和柔性基底通过转移的方法相结合。
如图1所示的传统的硅基薄膜体声波谐振器常采用键合的方式进行封装，其封装工艺具体为：首先，在谐振器013的周围采用电镀的方法形成铜柱作为键合柱003，然后通过键合的方法，在一定的压力与温度下，使盖片001如硅片与键合柱003相键合，基底011作为封装体的一部份，从而形成封装结构。谐振结构013由顶电极002、压电层007与底电极009组成，其位于衬底的空腔010上，与此同时，在谐振结构与盖片之间也存在空气隙002，由于谐振结构的材料与空气的声阻抗之间大的失配，从而将谐振结构与衬底和盖片声学隔离。
但对于柔性薄膜体声波谐振器来说，如果只是图1中的硅基薄膜体声波谐振器中的衬底替换成柔性衬底，然后采用现有技术的封装工艺可行性不高。因为在键合时需要高压力和高温度，和柔性衬底所能承受的温度及压力不兼容，同时当基底和封装层为柔性材料时，在键合的过程中，器件下方和上方的空腔容易发生塌陷，使器件部分与基底或封装层相接触，在接触部位会导致声波的泄露，从而降低了谐振器的Q值。
发明内容
有鉴于此，本发明提供一种柔性基底薄膜体声波谐振器及其形成方法，有助于提高器件的Q值，改善器件性能。
本发明一方面提出一种柔性基底薄膜体声波谐振器的形成方法，包括：提供牺牲层；在所述牺牲层之上形成谐振结构；在所述谐振结构之上形成顶部声反射结构；去除所述牺牲层，从而得到堆叠结构，然后将所述堆叠结构通过翻转工艺转移到柔性基底上，所述堆叠结构包括所述谐振结构和所述顶部声反射结构；在所述顶部声反射结构之上形成封装层。
可选地，还包括形成底部声反射结构，所述底部声反射结构位于所述柔性基底之上并且位于所述谐振结构之下。
可选地，所述顶部声反射结构包括：1层低声阻抗层；或者，1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
可选地，所述底部声反射结构包括：1层低声阻抗层；或者，1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
可选地，所述谐振结构包括自下而上依次排列的：第一电极、第一压电层和第二电极；或者，第一电极、第一压电层、第二电极、第二压电层、第三电极；或者，第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。
可选地，还包括形成空腔，所述空腔位于所述柔性基底之上并且位于所述谐振结构之下。
可选地，所述低声阻抗层包括：环氧基树脂、聚乙二烯、氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧烷、包含甲基倍半硅氧烷和氢硅倍半环氧乙烷的纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯或SiLK。
可选地，所述低声阻抗层的厚度小于1μm。
可选地，所述高声阻抗层包括：丁基合成橡胶、聚乙烯、氯丁橡胶、钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。
可选地，所述低声阻抗层的厚度小于1μm
可选地，所述封装层包括：聚酰亚胺或橡胶。
可选地，所述封装层的厚度小于1μm。
可选地，所述在所述顶部声反射结构之上形成封装层的步骤包括：在所述顶部声反射结构之上形成空气隙牺牲层；在所述空气隙牺牲层之上通过旋涂方式形成所述封装层；去除所述空气隙牺牲层从而形成空气隙。
本发明另二方面提出一种柔性基底薄膜体声波谐振器，包括柔性基底、谐振结构、顶部声反射结构、以及封装层，其中：所述谐振结构位于所述柔性基底之上；所述顶部声反射结构位于所述谐振结构之上；所述封装层位于所述顶部声反射结构之上。
可选地，还包括底部声反射结构，所述底部声反射结构位于所述柔性基底之上并且位于所述谐振结构之下。
可选地，所述顶部声反射结构包括：1层低声阻抗层；或者，1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
可选地，所述底部声反射结构包括：1层低声阻抗层；或者，1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
可选地，其特征在于，所述谐振结构包括自下而上依次排列的：第一电极、第一压电层和第二电极；或者，第一电极、第一压电层、第二电极、第二压电层、第三电极；或者，第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。
可选地，还包括：空腔，所述空腔位于所述柔性基底之上并且位于所述谐振结构之下。
可选地，所述低声阻抗层包括：环氧基树脂、聚乙二烯、氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧烷、包含甲基倍半硅氧烷和氢硅倍半环氧乙烷的纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯或SiLK。
可选地，所述低声阻抗层的厚度小于1μm。
可选地，所述高声阻抗层包括：丁基合成橡胶、聚乙烯、氯丁橡胶、钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。
可选地，所述高声阻抗层的厚度小于1μm。
可选地，所述封装层包括：聚酰亚胺或橡胶。
可选地，所述封装层的厚度小于1μm。
可选地，还包括空气隙，所述空气隙位于所述顶部声反射结构和所述封装层之间。
本发明再一方面提出一种柔性基底薄膜体声波谐振器，该柔性基底薄膜体声波谐振器是用本发明的任一项所述的柔性基底薄膜体声波谐振器的形成方法加工得到的。
根据本发明的技术方案，第一方面，而且由于设置了顶部声反射结构，使得其上可以直接通过旋涂等类似的工艺条件在其表面形成封装层，避免采用键合封装工艺在器件顶部形成空腔，从而避免了现有技术问题，可有效保障器件的密封效果，提高了Q值，改善了器件性能。第二方面，因为顶部声反射结构能够有效提高声波反射的能力，能够将声波限制在谐振结构内，避免谐振结构中的能量泄露到封装层中，从而减少了谐振结构能量的损失，使其Q值整体提高。
附图说明
附图用于更好地理解本发明，不构成对本发明的不当限定。其中：
图1是现有技术中的薄膜压电体声波谐振器的结构示意图；
图2是本发明第一实施例的柔性基底薄膜体声波谐振器的结构示意图；
图3是本发明第二实施例的柔性基底薄膜体声波谐振器的结构示意图；
图4是本发明第三实施例的柔性基底薄膜体声波谐振器的结构示意图；
图5是本发明第四实施例的柔性基底薄膜体声波谐振器的结构示 意图；
图6是本发明第五实施例的柔性基底薄膜体声波谐振器的结构示意图；
图7是本发明第六实施例的柔性基底薄膜体声波谐振器的结构示意图；
图8是本发明第七实施例的柔性基底薄膜体声波谐振器的结构示意图；
图9是本发明第八实施例的柔性基底薄膜体声波谐振器的结构示意图；
图10是本发明第九实施例的柔性基底薄膜体声波谐振器的结构示意图；
图11A至图11F是本发明实施例的柔性基底薄膜体声波谐振器的形成方法的流程示意图。
具体实施方式
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。
在本发明的描述中，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发明和简化描述，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发明的限制。
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。在本发明的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本发明中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，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。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发明中的具体含义。
在本发明中，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。
本发明第一方面提出了柔性基底薄膜体声波谐振器的形成方法。
根据本发明实施例的柔性基底薄膜体声波谐振器的形成方法，包括：提供牺牲层；在牺牲层之上形成谐振结构；在谐振结构之上形成顶部声反射结构；去除牺牲层，从而得到堆叠结构，然后将堆叠结构通过翻转工艺转移到柔性基底上，堆叠结构包括谐振结构和顶部声反射结构；在顶部声反射结构之上形成封装层。
根据本发明实施例的柔性基底薄膜体声波谐振器的形成方法，第一方面，而且由于设置了顶部声反射结构，其上可以直接通过旋涂等类似的工艺条件在其表面形成封装层，避免采用键合封装工艺在器件 顶部形成空腔，从而避免了现有技术问题，可有效保障器件的密封效果，提高了Q值，改善了器件性能。第二方面，因为顶部声反射结构能够有效提高声波反射的能力，能够将声波限制在谐振结构内，避免谐振结构中的能量泄露到封装层中，从而减少了谐振结构能量的损失，使其Q值整体提高。
其中，牺牲层的材料以为二氧化硅(SiO 2)、磷硅玻璃(PSG)等类似材料，对柔性、声阻抗无要求，因为其作用是在硅基底上加工完器件后，通过湿法刻蚀工艺即用HF溶液，将其刻蚀掉，然后将器件转移下来。
其中，去除牺牲层可以采用湿法刻蚀的方法或者类似的干法刻蚀，将器件放于一定配比的氢氟酸溶液中，一段时间之后牺牲层被蚀刻干净并形成空腔，此时器件通过锚点结构悬浮于空腔上方。然后用带有粘附性的柔性基底贴于器件的表面，将其粘下翻转过来即形成柔性的FBAR器件。采用翻转的转移方法转移堆叠结构时无需使用印章、也无需对准，能够大大提高转移的效率、降低成本，并且可以实现器件大规模的转移。
其中，柔性基底可以是聚酰亚胺(PI)、聚二甲基硅氧烷(PDMS)、涤纶树脂(PET)聚碳酸酯(PC)、聚萘二甲酸乙二醇酯(PEN)、聚醚砜(PES)、聚醚酰亚胺(PEI)、聚乙烯醇(PVA)、各种含氟聚合物(FEP)等构成。
其中，封装层可以用聚酰亚胺、橡胶等类似材料，可以与基底材料相同或不同。封装层材料属性要求是具有柔性的，因为整个器件突出的就是柔性。封装层声阻抗最好为低声阻抗材料。封装层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
其中，形成封装层可以采用旋涂或喷涂等类似的工艺，旋涂的方 式为：将加工好的器件放在机台腔体内的底座上，通过抽真空的方式将器件固定住，然后通过喷管将封装材料滴到到器件的表面，通过连接基座的马达，使其旋转，从而将封装材料均匀的平铺在器件的表面，通过控制旋转的速度，可调节旋涂的封装层的厚度、均匀性等。旋涂工艺可以节省封装的成本，同时能够避免键合的方式导致空腔的塌陷。
其中，谐振结构的具体形式是灵活多样的。谐振结构可以是最简单的三明治结构，包括自下而上依次排列的第一电极、第一压电层和第二电极。谐振结构也可以是“3+2”夹心结构，包括自下而上依次排列的第一电极、第一压电层、第二电极、第二压电层、第三电极。谐振结构还可以是两个垂直方向堆叠的三明治结构，包括自下而上依次排列的第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。需要说明的是，电极材料可以为金(Au)、钨(W)、钼(Mo)、铂(Pt)，钌(Ru)、铱(Ir)、铝(Al)、钛(Ti)等金属以及它们的合金。压电层材料可以为氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO 3)、石英(Quartz)、铌酸钾(KNbO 3)或钽酸锂(LiTaO 3)等材料以及它们的组合。
其中，顶部声反射结构可以包括：1层低声阻抗层或者1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。其中低声阻抗层和高声阻抗层的厚度均为四分之一或四分之三声波波长。当顶部声反射结构仅仅包含单层低声阻抗层时，器件具有轻薄、柔韧性好的优点。当顶部声反射结构包含1至2组“低声阻抗层-高声阻抗层”结构时，声波反射效果更佳。
其中，低声阻抗层由低声阻抗材料组成，通常可以是氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧烷、包含甲基倍半硅氧烷(methyl silsesquioxane，简称MSQ)和氢硅倍半环氧乙烷(hydrogen silsesquioxane，简称HSQ)的纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯、SiLK(SiLK是 Dow Chemical公司开发的一种低介电常数材料，目前广泛用于集成电路生产。目前已知它是一种高分子材料，但是具体结构仍然是商业秘密)或苯并环丁烯。低声阻抗层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
其中，高声阻抗层由高声阻材料组成，通常可以是钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。高声阻抗层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
优选地，器件的各层结构全部都采用柔性材料，这样能够有效提高器件的柔韧性、弯曲性，使其能够适应更加复杂的环境。具体地，低声阻抗层可以包括环氧基树脂或聚乙二烯。高声阻抗层可以包括：丁基合成橡胶、聚乙烯或氯丁橡胶。封装层可以包括聚酰亚胺或橡胶。需要说明的是，低声阻抗层、高声阻抗层和封装层既可以为上述特定材料的纯的高分子柔性材料，也可以为包含这上述特定材料的复合柔性材料。
可选地，本发明实施例的柔性基底薄膜体声波谐振器的形成方法还包括：形成底部声反射结构，该底部声反射结构位于柔性基底之上并且位于谐振结构之下。底部声反射结构也能够有效提高声波反射的能力，避免谐振器中的能量从底部泄露，将声波限制在谐振器内，从而减少了谐振器能量的损失，使其Q值整体提高。
可选地，本发明实施例的柔性基底薄膜体声波谐振器的形成方法中，底部声反射结构可以包括：1层低声阻抗层或者1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。当底部声反射结构仅仅包含单层低声阻抗层时，器件具有轻薄、柔韧性好的优点。当底部声反射结构包含1至2组“低声阻抗层-高声阻抗层” 结构时，声波反射效果更佳。
可选地，本发明实施例的柔性基底薄膜体声波谐振器的形成方法还包括：形成空腔，该空腔位于柔性基底之上并且位于谐振结构之下。该空腔中的空气的声阻抗为零，因此在谐振结构之下设置空腔也能够有效提高声波在空腔与谐振器底部二者之间界面处反射的能力，避免谐振结构中的能量泄露到柔性基底中，而是将声波限制在谐振结构内，从而减少了谐振结构能量的损失，使其Q值整体提高。
可选地，本发明实施例的柔性基底薄膜体声波谐振器的形成方法，还包括：在顶部声反射结构与封装层之间形成空气隙。具体做法可以是：在顶部声反射结构之上形成空气隙牺牲层；在空气隙牺牲层之上通过旋涂方式形成封装层；去除空气隙牺牲层从而形成空气隙。
本发明第二方面提出了柔性基底薄膜体声波谐振器。
根据本发明实施例的柔性基底薄膜体声波谐振器，包括：柔性基底、谐振结构、顶部声反射结构、以及封装层。其中：谐振结构位于柔性基底之上；顶部声反射结构位于谐振结构之上；封装层位于顶部声反射结构之上。
根据本发明实施例的柔性基底薄膜体声波谐振器，第一方面，而且由于设置了顶部声反射结构，其上可以直接通过旋涂等类似的工艺条件在其表面形成封装层，避免采用键合封装工艺在器件顶部形成空腔，从而避免了现有技术问题，可有效保障器件的密封效果，提高了Q值，改善了器件性能。第二方面，因为顶部声反射结构能够有效提高声波反射的能力，能够将声波限制在谐振结构内，避免谐振结构中的能量泄露到封装层中，从而减少了谐振结构能量的损失，使其Q值整体提高。
其中，柔性基底可以是聚酰亚胺(PI)、聚二甲基硅氧烷(PDMS)、涤纶树脂(PET)聚碳酸酯(PC)、聚萘二甲酸乙二醇酯(PEN)、聚醚砜(PES)、聚醚酰亚胺(PEI)、聚乙烯醇(PVA)、各种含氟聚合物(FEP)等构成。
其中，封装层可以用聚酰亚胺、橡胶等类似材料，可以与基底材料相同或不同。封装层材料属性要求是具有柔性的，因为整个器件突出的就是柔性。封装层声阻抗最好为低声阻抗材料。封装层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
其中，谐振结构的具体形式是灵活多样的。谐振结构可以是最简单的三明治结构，包括自下而上依次排列的第一电极、第一压电层和第二电极。谐振结构也可以是“3+2”夹心结构，包括自下而上依次排列的第一电极、第一压电层、第二电极、第二压电层、第三电极。谐振结构还可以是两个三明治结构垂直方向堆叠，包括自下而上依次排列的第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。需要说明的是，电极材料可以为金(Au)、钨(W)、钼(Mo)、铂(Pt)，钌(Ru)、铱(Ir)、铝(Al)、钛(Ti)等金属以及它们的合金。压电层材料可以为氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO 3)、石英(Quartz)、铌酸钾(KNbO 3)或钽酸锂(LiTaO 3)等材料以及它们的组合。
其中，顶部声反射结构可以包括：1层低声阻抗层；或者，1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。当顶部声反射结构仅仅包含单层低声阻抗层时，器件具有轻薄、柔韧性好的优点。当顶部声反射结构包含1至2组“低声阻抗层-高声阻抗层”结构时，声波反射效果更佳。
需要说明的是，低声阻抗层由低声阻抗材料组成，可以是氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧 烷、包含甲基倍半硅氧烷(methyl silsesquioxane，简称MSQ)和氢硅倍半环氧乙烷(hydrogen silsesquioxane，简称HSQ)的纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯、SiLK或苯并环丁烯。低声阻抗层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
高声阻抗层由高声阻材料组成，可以是钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。高声阻抗层的厚度小于1μm，由于它是很薄的薄膜，增加了器件的柔性。
优选地，器件的各层结构全部都采用柔性材料，这样能够有效提高器件的柔韧性、弯曲性，使其能够适应更加复杂的环境。具体地，低声阻抗层可以包括环氧基树脂或聚乙二烯。高声阻抗层可以包括：丁基合成橡胶、聚乙烯或氯丁橡胶。封装层可以包括聚酰亚胺或橡胶。需要说明的是，低声阻抗层、高声阻抗层和封装层既可以为上述特定材料的纯的高分子柔性材料，也可以为包含这上述特定材料的复合柔性材料。
可选地，本发明实施例的柔性基底薄膜体声波谐振器还包括底部声反射结构，该底部声反射结构位于柔性基底之上并且位于谐振结构之下。底部声反射结构也能够有效提高声波反射的能力，避免谐振器中的能量泄露到柔性基底中，将声波限制在谐振器内，从而减少了谐振器能量的损失，使其Q值整体提高。
可选地，本发明实施例的柔性基底薄膜体声波谐振器中，底部声反射结构可以包括：1层低声阻抗层或者1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。当底部声反射结构仅仅包含单层低声阻抗层时，器件具有轻薄、柔韧性好的优点。 当底部声反射结构包含1至2组“低声阻抗层-高声阻抗层”结构时，声波反射效果更佳。
可选地，本发明实施例的柔性基底薄膜体声波谐振器还包括空腔。该空腔位于柔性基底之上并且位于谐振结构之下。该空腔中的空气的声阻抗为零，因此在谐振结构之下设置空腔也能够有效提高声波在空腔与谐振器底部二者之间界面处反射的能力，避免谐振结构中的能量泄露到柔性基底中，而是将声波限制在谐振结构内，从而减少了谐振结构能量的损失，使其Q值整体提高。
可选地，本发明实施例的柔性基底薄膜体声波谐振器还包括空气隙，该空气隙位于顶部声反射结构和封装层之间。
为使本领域技术人员更好地理解本发明，下面列举多个具体实施例进行说明。
图2是本发明第一实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)200包括柔性基底219；空腔217；谐振结构214，其包含底部电极215、压电层213和顶部电极211；顶部声反射结构210，其包含两组布拉格反射结构，即低声阻抗层209和205以及高声阻抗层207和203；以及封装层201；其中，空腔217起到对谐振结构214声学隔离的目的。在谐振结构中，底部电极、压电层、顶部电极以及空腔在垂直方向上重叠的部分为谐振器的有效区域，当在谐振器的上下电极间施加一定频率的交变电压信号时，由于压电材料所具有的逆压电效应，有效区域内的上下电极之间会产生垂直方向传播的声波，声波将会在底部电极与空气的交界面以及顶部电极上的布拉格反射结构之间来回反射并在一定频率下产生谐振。
柔性FBAR 200的制作过程包括，首先在单晶硅基底上加工出顶部 带有顶部声反射结构的FBAR，其制造顺序依次为：在硅基底(约400μm厚)上刻蚀形成空腔并沉积一层牺牲材料，通过化学机械平坦化使其表面光滑平整，形成牺牲层(约3.4μm厚)；沉积谐振结构；沉积顶部声反射结构；然后将牺牲层去除；最后在显微操作下通过印章转移的方法，将在硅基底上制备好的带有顶部声反射结构的FBAR器件堆叠提起，按照对准标记将其放置到柔性基底上，从而形成柔性的FBAR器件，然后在顶部声反射结构的表面通过旋涂等类似的工艺方法形成封装层。
由上可知，图2所示的柔性基底薄膜体声波谐振器及其制作方法可以显著提高谐振器封装后的Q值，因为顶部声反射结构能够有效提高声波反射的能力，避免谐振器中的能量泄露到封装层中，将声波限制在谐振器内，从而减少了谐振器能量的损失，使其Q值整体提高。而且由于顶部声反射结构的存在，使得器件可以直接通过旋涂等类似的工艺条件在其表面形成封装层，可有效解决柔性器件封装的问题，同时使得器件的封装过程变得更为简便、降低了器件封装的成本，并且能够有效降低柔性封装中对气密性的要求。
图3本发明第二实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)300包括柔性基底323；底部声反射结构320，其包含底部第一高声阻抗层321、底部第一低声阻抗层319、底部第二高声阻抗层317和底部第二低声阻抗层315；谐振结构314，其包含：底部电极313、压电层312和顶部电极311；顶部声反射结构304，其包含顶部第一高声阻抗层303、顶部第一低声阻抗层305、顶部第二高声阻抗层307和顶部第二低声阻抗层309；以及封装层301。由底部声反射结构和顶部声反射结构构成的声反射镜结构能够起到对声波的限制作用，当谐振结构中产生的声波向下传递到底部声反射结构中和向上传递到顶部声反射结构中，声反射镜结构能够在谐振结构与柔性基底和封装层之间起到声学隔离的作用，从而阻止声波能量泄露到柔性基底或封装层之中，避免声学损耗， 进而提高器件的Q值。
柔性FBAR 300的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；其次沉积底部声反射结构320；沉积谐振结构314；沉积顶部声反射结构304；然后将牺牲层去除；然后将堆叠结构转移到柔性基底323上，最后在器件顶部形成封装层301。
由上可知，图3所示的柔性基底薄膜体声波谐振器及其制作方法中，由于在谐振结构314的上下部分都有限制声波的布拉格反射结构，所以基底可以为任何的柔性材料，能够自由地选择成本更加低廉的柔性材料，使得器件制作的成本降低，并且能够扩大器件应用的范围，使其能够适应更加复杂的环境；由于在谐振结构314上下所形成的布拉格反射结构，使得器件抵抗外界环境变化的能力增强，如湿度、颗粒吸附等对器件频率的影响，而且还可以直接通过旋涂等类似的工艺在其表面上形成封装层，大大减少了器件封装的工艺步骤，使其在封装的过程中变得更加简单，进一步降低了器件封装的成本；布拉格反射结构的存在，可以降低器件对封装气密性的要求，并且基底上没有空腔的存在，器件的连接将更为牢固。
图4是本发明第三实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)400包括柔性基底415；底部声反射结构412，其包含底部第一高声阻抗层413、底部第一低声阻抗层411；谐振结构410，其包含：底部电极407、压电层406和顶部电极405；顶部声反射结构404，其包含顶部第一高声阻抗层402、顶部第一低声阻抗层403；以及封装层401。
柔性FBAR 400的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；其次沉积底部声反射结构412；沉积谐振结构410；沉 积顶部声反射结构404；然后将牺牲层去除；然后将堆叠结构转移到柔性基底415上，最后在器件顶部形成封装层401。
由上可知，图4所示的柔性基底薄膜体声波谐振器及其制作方法中，如果构成布拉格反射结构的层数过多，则器件在弯曲的过程中容易断裂，不利于其在柔性方面的应用，因此将底部声反射结构和顶部声反射结构的材料组数设置为一组，这样能够有效增加器件的柔韧性，能够使其应用在更加复杂的环境之中。
图5是本发明第四实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)500包括柔性基底513；底部声反射结构511，其只包含单层低声阻抗层；谐振结构510，其包含：底部电极509、压电层507和顶部电极505；顶部声反射结构503，其只包含单层低声阻抗层；以及封装层501。
柔性FBAR 500的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；其次沉积底部声反射结构511；沉积谐振结构510；沉积顶部声反射结构503；然后将牺牲层去除；然后将堆叠结构转移到柔性基底513上，最后在器件顶部形成封装层501。
由上可知，图5所示的柔性基底薄膜体声波谐振器及其制作方法中，由于构成布拉格反射结构的层数过多，则器件在弯曲的过程中容易断裂，不利于其在柔性方面的应用，因此将底部和顶部的布拉格反射结构的数量都只设置为单层，这样能够有效增加器件的柔韧性，能够使其应用在更加复杂的环境之中。
图6是本发明第五实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)600包括柔性基底617；谐振结构616，其包含：底部电极615、压电层613和 顶部电极611；顶部声反射结构610，其包含顶部第一高声阻抗层603、顶部第一低声阻抗层605、顶部第二高声阻抗层607和顶部第二低声阻抗层609；以及封装层601。
柔性FBAR 600的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；沉积谐振结构616；沉积顶部声反射结构610；然后将牺牲层去除；最后，通过印章转移的方法，在显微操作下，将在硅基底上制备好的带有顶部声反射结构的FBAR提起，直接将其放置到柔性基底617上，从而形成柔性的FBAR，然后在器件的表面通过旋涂等类似的工艺方法形成封装层601。
在此实施例中，柔性基底的材料为聚酰亚胺(PI)或聚对二甲苯等声阻抗接近为零的类似材料，柔性基底的厚度范围在但不限于10μm至400μm之间。由声波理论可知，声波会在声阻抗不同的两种介质的界面上会发生反射，其反射系数R与透射系数T分别为：
Figure PCTCN2018112083-appb-000001
其中Z1，Z2为不同介质的声阻抗。从上述公式中可以看出，当两种介质的声阻抗相等时，反射系数R＝0，透射系数T＝1，此时声波会直接通过这两种介质，不会发生反射。当Z1>>Z2时，R＝1，T＝0；可见要想提高声波反射系数，两种介质的声阻抗比越大越好。由于PI基底的声阻抗接近与空气，与其他膜层构成的声阻抗比较大，因此可以采用PI或聚对二甲苯等声阻抗接近为零的类似材料作为基底可以实现较好的限制声波的效果。
由上可知，图6所示的柔性基底薄膜体声波谐振器及其制作方法中，由于在谐振结构的上下部分都没有空腔的存在，使得器件与柔性基底和封装层之间的连接更为牢固，同时不用在基底上加工空腔，可以简化工艺步骤；柔性基底上没有空腔，器件在转移的过程中不用进 行对准，大大提高了器件转移的效率；布拉格反射结构的存在，使得器件可以直接通过旋涂等类似的工艺条件在其表面形成封装层，可有效解决柔性器件封装的问题，同时使得器件的封装过程变得更为简便、降低了器件封装的成本，并且能够有效降低柔性封装中对气密性的要求，使得器件封装的稳定性提高，增加了器件使用的可靠性。
图7是本发明第六实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性堆叠式薄膜体声波谐振器(FBAR)700包括：柔性基底723；底部声反射结构720，其包含底部第一高声阻抗层721和底部第一低声阻抗层718；第一电极715，第一压电层713，第二电极711，第二压电层709和第三电极707；顶部声反射结构702，其包含顶部第一高声阻抗层703和顶部第一低声阻抗层705。
柔性堆叠式FBAR 700的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的堆叠式FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；沉积底部声反射结构；沉积第一电极、第一压电层、第二电极、第二压电层、第三电极；沉积顶部声反射结构；然后将牺牲层去除；然后将堆叠结构转移到柔性基底723上，最后在器件顶部形成封装层701。根据本发明的制作方法，可对柔性堆叠式薄膜体声波谐振器进行简单封装。
图8是本发明第七实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性耦合谐振滤波器800包括：柔性基底823；底部声反射结构820，其包含底部第一高声阻抗层821和底部第一低声阻抗层819；第一谐振器812，其包含第一底部电极817、第一压电层815和第一顶部电极813；解耦层811；第二谐振器804，其包含第二底部电极809、第二压电层807和第二顶部电极805；顶部声反射结构802，其包含顶部第一高声阻抗层801和顶部第一低声阻抗层803；封装层801。
柔性堆叠式FBAR 800的制作过程包括，首先在单晶硅基底上加工出带有布拉格反射结构的耦合谐振滤波器，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；沉积底部声反射结构；沉积第一谐振器；沉积解耦层；沉积第二谐振器；沉积顶部声反射结构；然后将牺牲层去除；然后将堆叠结构转移到柔性基底823上，最后在器件顶部形成封装层801。根据本发明的制作方法，可对柔性堆叠式薄膜体声波谐振器进行简单封装。
图9是本发明的第八实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)900包括柔性基底917；谐振结构916，其包含：底部电极915、压电层913和顶部电极911；以及封装层919。该封装层919优选采用柔性的低声阻抗材料，如PI、PET等。这样封装层919既起到机械封装作用，同时又能起到声波密封作用。
柔性FBAR900的制作过程包括，首先在单晶硅基底上加工出FBAR，制造顺序依次为：在硅基底上形成空腔并沉积一层牺牲层；沉积谐振结构916；然后将牺牲层去除；然后将堆叠结构转移到柔性基底917上，最后在器件顶部形成封装层919。
由前文提到的公式
Figure PCTCN2018112083-appb-000002
可知，要想提高声波反射系数，两种介质的声阻抗比越大越好。因此在此实施例中，柔性基底和封装层的材料都选择聚酰亚胺(PI)或聚对二甲苯等声阻抗尽接近为零的类似材料，其中柔性基底的材料与封装层的材料可以相同或不同。
由上可知，图9所示的柔性基底薄膜体声波谐振器及其制作方法中，选用声阻抗尽量接近为零的材料以旋涂的方式进行封装，可以实 现器件在封装的同时能够将声波很好的限定在谐振结构之内，使得器件不仅能够很好的抵抗外界环境变化对其性能的影响，而且还能很好的保证器件的Q值。
图10是本发明的第九实施例的柔性基底薄膜体声波谐振器的结构示意图。在此典型实施例中，柔性薄膜体声波谐振器(FBAR)1000包括柔性基底1017；谐振结构1016，其包含：底部电极1015、压电层1013和顶部电极1011；封装层1019；以及位于顶部电极和封装层之间的空气隙1010。在此发明实施例中，位于顶部电极和封装层之间的空气隙，能够同时提高声波的反射率以及弯曲性能。由于空气的声阻抗为零，所以空气隙的存在能够有效提高声波反射回谐振器中的反射率；同时由于空气隙的存在使得器件在弯曲的过程中更加容易，能够提高器件的弯曲性能，使得器件可以适应更加复杂的环境。需要说明的是，在此实施例中所提出的空气隙也应用于本发明中的任一实施例中，但在其它实施例附图中并未标示出，该空气隙位于顶部声反射结构和封装层之间。
该空气隙结构的加工方法为：将谐振结构(即堆叠结构)转移到柔性基底上之后，通过PECVD、CVD或PVD等类似的薄膜沉积工艺，在顶部声反射层上沉积一层空气隙牺牲层，空气隙牺牲层的材料可以为二氧化硅(SiO 2)或磷硅玻璃(PSG)等类似的材料，然后在空气隙牺牲层的上方通过旋涂的工艺方法形成封装层，最后通过湿法刻蚀(使用氢氟酸溶液)或干法刻蚀等类似的工艺条件，将空气隙牺牲层去除从而形成了空气隙结构。
图11A至11F为根据本发明的实施例的柔性基底薄膜体声波谐振器的形成方法的流程示意图。该典型实施例中，完整的柔性基底薄膜体声波谐振器加工方法具体步骤如下：
首先，在硅基底上通过干法刻蚀工艺形成空腔并填充牺牲材料1001如磷硅玻璃(Phospho-Silicate-Glass，简称PSG)等，并通过化学机械平坦化使薄膜的表面变得平坦光滑，如图11A所示。
然后，在牺牲层1101上通过等离子体增强化学的气相沉积法(Plasma Enhanced Chemical Vapor Deposition，简称PECVD)、物理气相沉积(Physical Vapor Deposition，简称PVD)、化学气相沉积(Chemical Vapor Deposition，简称CVD)等类似的薄膜沉积工艺沉积底部声反射结构1106的底部高声阻抗层1105和底部低声阻抗层1107，如图11B所示。
通过薄膜沉积工艺在底部声反射结构1106的底部低声阻抗层1107上沉积底部电极1109，然后通过光刻、刻蚀、去胶的工艺形成底部电极图案，之后使用相同的工艺在底部电极上沉积压电层1111，最后在压电层上形成顶部电极1113，如图11C所示。
通过薄膜沉积工艺在谐振结构1110的顶部电极上沉积顶部声反射结构1116的顶部低声阻抗层1115和顶部高声阻抗层1117，如图11D所示。
将在硅基底上加工好的器件放入特定配比的氢氟酸(HF)中，进行PSG的释放形成空腔1103，然后使用带有粘附性的柔性基底1100贴到器件的表面，通过翻转(flip)的工艺形成柔性薄膜体声波谐振器，如图11E、11F所示。
最后的封装步骤可采用声阻抗尽可能接近为零同时为柔性的材料如聚酰亚胺(PI)，通过旋涂等类似的工艺方法进行封装。
由上可知，通过本发明实施例的柔性基底薄膜体声波谐振器的制作方法，可以使器件在转移的过程中无需印章、无需对准，因而使得 转移的过程更加容易简便，能够进一步提高器件转移效率。密封效果好，器件Q值高。
本发明还提出一种柔性基底薄膜体声波谐振器，该柔性基底薄膜体声波谐振器是用任意一种本发明实施例的柔性基底薄膜体声波谐振器的形成方法加工得到的。
上述具体实施方式，并不构成对本发明保护范围的限制。本领域技术人员应该明白的是，取决于设计要求和其他因素，可以发生各种各样的修改、组合、子组合和替代。任何在本发明的精神和原则之内所作的修改、等同替换和改进等，均应包含在本发明保护范围之内。

Claims (27)

  1. 一种柔性基底薄膜体声波谐振器的形成方法，其特征在于，包括：
    提供牺牲层；
    在所述牺牲层之上形成谐振结构；
    在所述谐振结构之上形成顶部声反射结构；
    去除所述牺牲层，从而得到堆叠结构，然后将所述堆叠结构通过翻转工艺转移到柔性基底上，所述堆叠结构包括所述谐振结构和所述顶部声反射结构；
    在所述顶部声反射结构之上形成封装层。
  2. 根据权利要求1所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，还包括形成底部声反射结构，所述底部声反射结构位于所述柔性基底之上并且位于所述谐振结构之下。
  3. 根据权利要求1或2所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述顶部声反射结构包括：
    1层低声阻抗层；或者，
    1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
  4. 根据权利要求1或2所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述底部声反射结构包括：
    1层低声阻抗层；或者，
    1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
  5. 根据权利要求1或2所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述谐振结构包括自下而上依次排列的：
    第一电极、第一压电层和第二电极；或者，
    第一电极、第一压电层、第二电极、第二压电层、第三电极；或者，
    第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。
  6. 根据权利要求1所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，还包括形成空腔，所述空腔位于所述柔性基底之上并且位于所述谐振结构之下。
  7. 根据权利要求3所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述低声阻抗层包括：环氧基树脂、聚乙二烯、氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧烷、包含甲基倍半硅氧烷和氢硅倍半环氧乙烷纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯或SiLK。
  8. 根据权利要求3所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述低声阻抗层的厚度小于1μm。
  9. 根据权利要求3所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述高声阻抗层包括：丁基合成橡胶、聚乙烯、氯丁橡胶、钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。
  10. 根据权利要求3所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述高声阻抗层的厚度小于1μm。
  11. 根据权利要求1所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述封装层包括：聚酰亚胺或橡胶。
  12. 根据权利要求1所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述封装层的厚度小于1μm。
  13. 根据权利要求1所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述在所述顶部声反射结构之上形成封装层的步骤包括：
    在所述顶部声反射结构之上形成空气隙牺牲层；
    在所述空气隙牺牲层之上通过旋涂方式形成所述封装层；
    去除所述空气隙牺牲层从而形成空气隙。
  14. 一种柔性基底薄膜体声波谐振器，其特征在于，包括柔性基底、谐振结构、顶部声反射结构、以及封装层，其中：
    所述谐振结构位于所述柔性基底之上；
    所述顶部声反射结构位于所述谐振结构之上；
    所述封装层位于所述顶部声反射结构之上。
  15. 根据权利要求14所述的柔性基底薄膜体声波谐振器，其特征在于，还包括底部声反射结构，所述底部声反射结构位于所述柔性基底之上并且位于所述谐振结构之下。
  16. 根据权利要求14或15所述的柔性基底薄膜体声波谐振器，其特征在于，所述顶部声反射结构包括：
    1层低声阻抗层；或者，
    1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
  17. 根据权利要求14或15所述的柔性基底薄膜体声波谐振器，其特征在于，所述底部声反射结构包括：
    1层低声阻抗层；或者，
    1至2组布拉格反射结构，其中每组布拉格反射结构包括低声阻抗层和高声阻抗层。
  18. 根据权利要求14或15所述的柔性基底薄膜体声波谐振器，其特征在于，所述谐振结构包括自下而上依次排列的：
    第一电极、第一压电层和第二电极；或者，
    第一电极、第一压电层、第二电极、第二压电层、第三电极；或者，
    第一电极、第一压电层、第二电极、解耦层、第三电极、第二压电层、第四电极。
  19. 根据权利要求14所述的柔性基底薄膜体声波谐振器，其特征在于，还包括：空腔，所述空腔位于所述柔性基底之上并且位于所述谐振结构之下。
  20. 根据权利要求16所述的柔性基底薄膜体声波谐振器，其特征在于，所述低声阻抗层包括：环氧基树脂、聚乙二烯、氧化硅、铝、碳掺杂氧化硅、纳米多孔甲基倍半硅氧烷、纳米多孔氢倍半硅氧烷、包含甲基倍半硅氧烷和氢硅倍半环氧乙烷的纳米多孔混合物、纳米玻璃、气凝胶、干凝胶、旋涂玻璃、聚对二甲苯或SiLK。
  21. 根据权利要求16所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述低声阻抗层的厚度小于1μm。
  22. 根据权利要求16所述的柔性基底薄膜体声波谐振器，其特征在于，所述高声阻抗层包括：丁基合成橡胶、聚乙烯、氯丁橡胶、钨、钼、铂、钌、铱、钨钛、五氧化二钽、氧化哈、氧化铝、硅化络、碳化铌、氮化钽、碳化钛、氧化钛、碳化钒、氮化钨、氧化钨、碳化锆、类金刚石或硅掺杂的金刚石。
  23. 根据权利要求16所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述高声阻抗层的厚度小于1μm。
  24. 根据权利要求14所述的柔性基底薄膜体声波谐振器，其特征在于，所述封装层包括：聚酰亚胺或橡胶。
  25. 根据权利要求14所述的柔性基底薄膜体声波谐振器的形成方法，其特征在于，所述封装层的厚度小于1μm。
  26. 根据权利要求14所述的柔性基底薄膜体声波谐振器，其特征在于，还包括空气隙，所述空气隙位于所述顶部声反射结构和所述封装层之间。
  27. 一种柔性基底薄膜体声波谐振器，其特征在于，该柔性基底薄膜体声波谐振器是用权利要求1至13中任一项所述的方法加工得到。
PCT/CN2018/112083 2018-09-30 2018-10-26 柔性基底薄膜体声波谐振器及其形成方法 WO2020062384A1 (zh)

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Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109889181B (zh) * 2019-03-26 2020-09-29 电子科技大学 一种复合柔性体声波谐振器及其制备方法
CN112057415A (zh) * 2019-06-10 2020-12-11 海得摩尔医药科技有限公司 透皮给药凝胶制剂和其应用
WO2020258334A1 (zh) * 2019-06-28 2020-12-30 瑞声声学科技(深圳)有限公司 谐振器及其制备方法
CN111211757B (zh) * 2020-02-05 2024-03-15 见闻录(浙江)半导体有限公司 一种体声波谐振器的顶电极结构及制作工艺
CN111669144B (zh) * 2020-05-06 2023-09-22 广州市艾佛光通科技有限公司 一种baw体声波谐振器及其制备方法、滤波器
CN112383287A (zh) * 2020-11-27 2021-02-19 广东省科学院半导体研究所 声表面波谐振器及其制备方法
CN113364423B (zh) * 2021-05-27 2023-11-10 广州乐仪投资有限公司 压电mems谐振器及其形成方法、电子设备
CN113572444B (zh) * 2021-09-23 2022-02-18 深圳新声半导体有限公司 用于体声波谐振器制作的方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102291095A (zh) * 2011-04-27 2011-12-21 庞慰 复合体声波谐振器
JP5302796B2 (ja) * 2009-06-30 2013-10-02 京セラクリスタルデバイス株式会社 圧電デバイスの製造方法
CN103607178A (zh) * 2013-09-17 2014-02-26 诺思（天津）微系统有限公司 薄膜体波谐振器及提高其品质因数的方法
CN106209003A (zh) * 2016-07-06 2016-12-07 中国科学院上海微系统与信息技术研究所 利用薄膜转移技术制备薄膜体声波器件的方法
CN107508569A (zh) * 2017-08-07 2017-12-22 电子科技大学 一种薄膜体声波谐振器的制备方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101692602B (zh) * 2009-09-28 2012-09-05 清华大学 单层电极薄膜体声波谐振器结构及其制造方法
CN101908865B (zh) * 2010-08-20 2014-02-12 庞慰 体波谐振器及其加工方法
CN103929149B (zh) * 2014-04-21 2017-05-10 电子科技大学 一种柔性压电薄膜体声波谐振器及其制备方法
CN106788318B (zh) * 2016-11-22 2020-03-06 山东科技大学 一种在柔性基底上制造薄膜体声波谐振器的方法
CN106876577B (zh) * 2017-03-09 2019-05-28 电子科技大学 Dast柔性复合压电材料及其制备方法
CN107941391B (zh) * 2017-11-17 2020-04-28 杭州电子科技大学 一种用于薄膜体声波压力传感器的无线无源温度补偿方法
CN108092639B (zh) * 2017-12-21 2020-12-22 华南理工大学 一种微纳米柱柔性阵列薄膜体声波谐振子滤波器及其制备

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5302796B2 (ja) * 2009-06-30 2013-10-02 京セラクリスタルデバイス株式会社 圧電デバイスの製造方法
CN102291095A (zh) * 2011-04-27 2011-12-21 庞慰 复合体声波谐振器
CN103607178A (zh) * 2013-09-17 2014-02-26 诺思（天津）微系统有限公司 薄膜体波谐振器及提高其品质因数的方法
CN106209003A (zh) * 2016-07-06 2016-12-07 中国科学院上海微系统与信息技术研究所 利用薄膜转移技术制备薄膜体声波器件的方法
CN107508569A (zh) * 2017-08-07 2017-12-22 电子科技大学 一种薄膜体声波谐振器的制备方法

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