WO2022057766A1 - 薄膜体声波谐振器的制造方法及滤波器 - Google Patents

薄膜体声波谐振器的制造方法及滤波器 Download PDF

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Publication number
WO2022057766A1
WO2022057766A1 PCT/CN2021/117995 CN2021117995W WO2022057766A1 WO 2022057766 A1 WO2022057766 A1 WO 2022057766A1 CN 2021117995 W CN2021117995 W CN 2021117995W WO 2022057766 A1 WO2022057766 A1 WO 2022057766A1
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electrode
forming
out structure
annular
bulk acoustic
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PCT/CN2021/117995
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English (en)
French (fr)
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黄河
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中芯集成电路（宁波）有限公司上海分公司
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Publication of WO2022057766A1 publication Critical patent/WO2022057766A1/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
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
    • 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
    • H03H9/02086—Means for compensation or elimination of undesirable effects
    • H03H9/02118—Means for compensation or elimination of undesirable effects of lateral leakage between adjacent resonators
    • 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
    • H03H9/02157—Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness
    • 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
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • 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
    • 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
    • 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
    • H03H9/205—Constructional features of resonators consisting of piezoelectric or electrostrictive material having multiple resonators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • H03H9/582—Multiple crystal filters implemented with thin-film techniques
    • H03H9/586—Means for mounting to a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/588—Membranes
    • 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
    • H03H2003/028—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 for obtaining desired values of other parameters
    • 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]
    • H03H2009/02188—Electrically tuning
    • H03H2009/02196—Electrically tuning operating on the FBAR element, e.g. by direct application of a tuning DC voltage

Definitions

  • the invention relates to the field of semiconductor device manufacturing, in particular to a method for manufacturing a thin-film bulk acoustic wave resonator and a filter.
  • RF front-end modules have gradually become the core components of communication equipment.
  • filters have become the most rapidly growing and most promising components.
  • the performance of the filter is determined by the resonator units that make up the filter.
  • FBARs thin-film bulk acoustic resonators
  • FBARs thin-film bulk acoustic resonators
  • a thin-film bulk acoustic wave resonator includes two thin-film electrodes, and a piezoelectric thin-film layer is arranged between the two thin-film electrodes.
  • the bulk acoustic wave propagating in the thickness direction of the electric film layer is transmitted to the interface between the upper and lower electrodes and the air and is reflected back, and then reflected back and forth inside the film to form an oscillation.
  • Standing wave oscillations are formed when a sound wave propagates in a piezoelectric film layer that is exactly an odd multiple of a half-wavelength.
  • the quality factor (Q) of the cavity-type thin-film bulk acoustic wave resonators produced at present cannot be further improved, so it cannot meet the needs of high-performance radio frequency systems.
  • the purpose of the present invention is to provide a method for manufacturing a thin film bulk acoustic wave resonator and a filter, which can improve the quality factor of the thin film bulk acoustic wave resonator, thereby improving the performance of the device.
  • the present invention provides a method for manufacturing a thin film bulk acoustic resonator, comprising: forming 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 is formed between the first electrode and the second electrode.
  • At least one of an electrode and a second electrode forms an annular groove penetrating the corresponding electrode; forming an electrode lead-out structure with an arch bridge on the electrode with the annular groove, including: forming an annular sacrificial protrusion; forming a covering annular sacrificial protrusion An electrode lead-out structure whose edge is overlapped on the edge of the electrode in the effective resonance area; a support layer is formed on the first electrode; the support layer is patterned to form a first cavity passing through the support layer; a first substrate is provided, the first lining The bottom covers the first cavity, and the arch bridge of the electrode lead-out structure is located in the range of the first cavity; the annular sacrificial protrusion is removed to form an annular space, and the annular space is opposite to the annular groove.
  • the present invention also provides a filter, comprising at least one thin-film bulk acoustic resonator formed by the above-mentioned manufacturing method of the thin-film bulk acoustic resonator.
  • the beneficial effects of the method for manufacturing a thin-film bulk acoustic resonator of the present invention are: forming an electrode lead-out structure with an arched bridge structure by forming annular sacrificial protrusions on the corresponding electrodes, and forming annular gaps after removing the annular sacrificial protrusions , in order to define the range of the effective resonance area, and then the corresponding electrodes are etched to form annular grooves running through the corresponding electrodes, which not only facilitates the simplification of the formation process of the electrode lead-out structure, but also separates the electrodes located inside and outside the annular groove.
  • the electrode extraction structure electrically connects the disconnected electrodes.
  • the boundary of the corresponding electrode is exposed to the annular gap formed by the arched bridge through the annular groove, so as to achieve the effect of eliminating the electrode boundary clutter in the effective resonance region, thereby improving the Q value of the resonator.
  • forming the first cavity by etching the support layer can simplify the forming process and reduce the manufacturing cost.
  • the piezoelectric layer is formed on a flat electrode or a carrier substrate, so that the upper surface and the lower surface of the piezoelectric layer are flat, so as to ensure that the piezoelectric layer has a good lattice orientation and improve the pressure of the piezoelectric layer. electrical characteristics, thereby improving the performance of the resonator.
  • the impedance of the electrode lead-out structure is lower than the impedance of the corresponding electrode, so as to reduce the electrode impedance, make the electrode lead-out structure have better conductivity, and improve the conductivity.
  • the electrode lead-out structure and the corresponding electrode without the electrode lead-out structure or the electrode lead-out structure respectively provided on the first electrode and the second electrode are at least partially staggered from each other in the peripheral area of the arched bridge, which can avoid the occurrence of potential floating.
  • the problem of high-frequency coupling can prevent the formation of parasitic capacitance, which is beneficial to improve the quality factor of the resonator.
  • first electrode and/or the second electrode extend from the effective resonance region to the first substrate on the periphery of the first cavity, which can improve the structural strength of the resonator.
  • electrode lead-out structures formed on the corresponding electrodes also It extends from the effective resonance region to the first substrate on the periphery of the first cavity, so as to improve the structural strength of the resonator.
  • the piezoelectric layer is a complete film layer, which can ensure the structural strength of the resonator and improve the yield of the resonator.
  • the piezoelectric layer is provided with a first groove, so that the edge of the piezoelectric layer is exposed to the gas, which can suppress the shear wave loss of the piezoelectric layer.
  • the Q value of the boosting resonator is provided with a first groove, so that the edge of the piezoelectric layer is exposed to the gas, which can suppress the shear wave loss of the piezoelectric layer.
  • the beneficial effect of the filter of the present invention is that the filter is formed by connecting the above-mentioned thin-film bulk acoustic wave resonators, so as to ensure that the filter has good structural stability, and the electrode impedance of the resonator is low, which can improve the performance of the filter. Conductivity, improve the accuracy of filtering.
  • FIG. 1 is a flowchart of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 1 of the present invention
  • FIGS. 2 to 5 show schematic structural diagrams corresponding to different steps of the method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 1 of the present invention
  • Figures 6 to 8 show schematic structural diagrams corresponding to different steps of another manufacturing method of the thin film bulk acoustic resonator formed in Example 1 of the present invention
  • Figures 9 to 11 show the thin film formed in Example 1 of the present invention Schematic diagrams of structures corresponding to different steps of another method of manufacturing a bulk acoustic wave resonator;
  • FIG. 1 is a flowchart of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 1 of the present invention
  • FIGS. 2 to 5 show schematic structural diagrams corresponding to different steps of the method for manufacturing a thin-film bulk
  • FIG. 12 is a schematic structural diagram of a thin-film bulk acoustic wave resonator manufactured according to the manufacturing method of a thin-film bulk acoustic wave resonator in Example 2;
  • FIGS. 13-19 are according to embodiments 3 Schematic diagram of the structure of the thin film bulk acoustic resonator manufactured by the manufacturing method of the thin film bulk acoustic resonator;
  • FIG. 20 is a schematic structural diagram of the thin film bulk acoustic wave resonator manufactured according to the manufacturing method of the thin film bulk acoustic resonator in Example 4.
  • Embodiment 1 is a flow chart of a method for manufacturing a thin film bulk acoustic resonator according to Embodiment 1 of the present invention. Referring to FIG. 1 , Embodiment 1 provides a method for manufacturing a thin film bulk acoustic resonator.
  • the method for manufacturing a thin film bulk acoustic resonator includes: : S01: forming a first electrode, a piezoelectric layer and a second electrode, and the piezoelectric layer is located between the first electrode and the second electrode; S02: forming at least one of the first electrode and the second electrode through the corresponding electrode annular groove; S03: forming an electrode lead-out structure with an arched bridge on an electrode with an annular groove, including: forming an annular sacrificial protrusion; electrode lead-out structure; S04: forming a support layer on the first electrode; patterning the support layer to form a first cavity penetrating the support layer, and the arch bridge of the electrode lead-out structure is located within the range of the first cavity; S05: providing a first cavity Substrate, the first substrate covers the first cavity; S06: remove the annular sacrificial protrusion to form an annular space, and the annular space is opposite to the annular groove.
  • Step S0N does not represent a sequential order.
  • One of the first electrode 21 and the second electrode 24 is provided with an electrode lead-out structure.
  • the method for manufacturing the thin-film bulk acoustic resonator will be described by taking the electrode lead-out structure formed on the first electrode 31 as an example, as shown in FIGS. 2 to 5 .
  • the manufacturing method of the thin film bulk acoustic resonator provided by the present embodiment will be described in detail with reference to FIGS.
  • the method for forming the first electrode 21, the piezoelectric layer 22 and the second electrode 24 includes: providing a carrier substrate 4; forming the second electrode 23, The piezoelectric layer 22 and the first electrode 21 are formed; after the first cavity 121 on the support layer 12 is covered by the first substrate 11, the carrier substrate 4 is removed; an electrode lead-out structure is formed on the first electrode, which specifically includes: After forming the first electrode and before forming the support layer, an electrode lead-out structure is formed on the first electrode.
  • a carrier substrate 4 which may be a semiconductor material such as silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), arsenic Indium (InAs), Gallium Arsenide (GaAs), Indium Phosphide (InP) or other III/V compound semiconductors.
  • the second electrode 23 , the piezoelectric layer 22 and the first electrode 21 are formed on the carrier substrate 4 in sequence, wherein the first electrode 21 and the second electrode 23 can be formed by a physical vapor deposition process and an etching process forming, the periphery of the first electrode 21 and/or the second electrode 23 extends to the supporting layer 12 on the periphery of the first cavity formed subsequently, so as to improve the structural strength of the resonator.
  • the first electrode 21 and the second electrode 23 are both When extending from the effective resonance region to the first cavity 121 or the first substrate 1 on the periphery of the acoustic mirror 51 , the strength of the resonator structure is better.
  • the piezoelectric layer 22 may be deposited using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition.
  • the upper surface and the lower surface of the piezoelectric layer 22 are both flat, so as to ensure that the piezoelectric layer 22 has a good lattice orientation and improve the piezoelectric layer 22. piezoelectric properties, thereby improving the overall performance of the resonator.
  • the periphery of the first electrode 21 is the outer edge of the overall structure
  • the periphery of the second electrode 23 is the outer edge of the overall structure
  • the effective resonance area is the area surrounded by the subsequently formed annular gap.
  • the corresponding electrodes may also be etched, so that a part of the first electrode 21 and/or the second electrode 23 extends around the first cavity On the peripheral support layer 12, at this time, in order to ensure the structural strength of the resonator, the electrodes partially extending to the periphery of the first cavity 121 on the first substrate 1 are symmetrically distributed to ensure the support strength, so that the electrodes cover part or All first cavities.
  • the material of the first electrode 21 and the second electrode 23 can be any suitable conductive material or semiconductor material known in the art, wherein the conductive material can be a metal material with conductive properties, for example, made of molybdenum (Mo), aluminum (Al), Copper (Cu), Tungsten (W), Tantalum (Ta), Platinum (Pt), Ruthenium (Ru), Rhodium (Rh), Iridium (Ir), Chromium (Cr), Titanium (Ti), Gold (Au), osmium (Os), rhenium (Re), palladium (Pd) and other metals, or a laminate of the above metals, and the semiconductor material is, for example, Si, Ge, SiGe, SiC, SiGeC et al.
  • the piezoelectric layer 22 can be made of aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO 3 ), quartz (Quartz), potassium niobate (KNbO 3 ) or Piezoelectric materials having a wurtzite crystal structure, such as lithium tantalate (LiTaO 3 ), and combinations thereof.
  • the piezoelectric layer 22 may further include rare earth metals such as at least one of scandium (Sc), erbium (Er), yttrium (Y) and lanthanum (La). .
  • the piezoelectric layer 22 may further include transition metals such as zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). at least one.
  • transition metals such as zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). at least one.
  • the first electrode 21 is etched to form an annular groove 24 , and the annular groove 24 is a closed annular shape, so that the first electrode 21 is disconnected at the position of the annular groove 24 , so as to connect the disconnected first electrodes 21 through the electrode extraction structure 3 formed subsequently. Since the impedance of the electrode extraction structure 3 formed subsequently is lower than that of the first electrode 21, the impedance.
  • the annular groove 24 can also expose the boundary of the first electrode 21 to the annular gap 32 formed subsequently, so as to achieve the effect of eliminating electrode boundary clutter in the effective resonance region, thereby improving the Q value of the resonator.
  • the effective resonance area is the area surrounded by the annular gap formed by the arch bridge structure of the electrode lead-out structure formed subsequently.
  • the piezoelectric layer 22 may also be etched to form a first trench 25 penetrating the piezoelectric layer 22, and the first trench 25 penetrates the pressure
  • the electrical layer 22 forms a reflection interface between the end face of the piezoelectric layer 22 and the gas in the first groove 25, thereby effectively suppressing the leakage of acoustic waves in the piezoelectric layer 22, avoiding parasitic resonance, and improving the quality factor of the resonator.
  • the piezoelectric layer 22 can be etched to form the first trench 25, and then the sacrificial material can be filled in the first trench 25 so that the upper surface of the piezoelectric layer is in contact with the piezoelectric layer.
  • the upper surface of 22 is flush, and then the first electrode 21 is formed thereon, the first electrode 21 is etched to form an annular groove, and the sacrificial material filled in the first groove 25 is removed, so that the formed annular groove 24 and the first groove 24 are formed.
  • the grooves 25 are opposite.
  • the projection of the first groove 25 on the surface of the piezoelectric layer 22 may partially overlap with the projection of the annular groove 24 on the surface of the piezoelectric layer 22 , or the projection of the first groove 25 on the surface of the piezoelectric layer 22 is completely located in The annular groove 24 is within the projection range of the surface of the piezoelectric layer 22 .
  • the projection of the first groove 25 on the surface of the piezoelectric layer 22 completely overlaps with the projection of the annular groove 24 on the surface of the piezoelectric layer 22, At this time, the sound wave suppression effect is better.
  • the first groove 25 is a closed annular shape, and the piezoelectric layer 22 around the annular gap 32 and the piezoelectric layer 22 around the annular gap 32 are isolated from each other; The piezoelectric layer 32 on the inner periphery is isolated from the piezoelectric layer on the periphery of the annular gap 32 by the discontinuity.
  • the first groove 25 is a closed annular shape, the effect of suppressing sound waves is better.
  • a first sacrificial material is deposited on the first electrode 21, the first sacrificial material fills the annular trench and the first trench and covers a portion of the first electrode 21 located in the peripheral region of the annular trench, the first sacrificial layer material
  • the first sacrificial layer material include phosphosilicate glass, low temperature silica, borophosphosilicate glass, germanium, amorphous carbon, polyimide, or photoresist.
  • the first sacrificial layer material on the first electrode 21 is patterned to form an annular sacrificial protrusion 32', which is a continuous structure, enclosing a closed ring, and the boundary of the ring defines the effective resonance of the resonator district boundary.
  • an electrode lead-out structure 3 is formed on the first electrode 21 , which covers the annular sacrificial protrusion 32 ′ and whose edge overlaps the edge of the first electrode 21 in the effective resonance region. material to form an electrode lead-out structure 3, the electrode lead-out structure 3 covers the first electrode 21 and the annular sacrificial protrusion 32' formed on the first electrode 21, and extends to the support layer 12 on the periphery of the first cavity.
  • the deposited conductive material covers part of the first electrode 21 and the annular sacrificial protrusion 32' and the first electrode 21 on the periphery of the annular sacrificial protrusion 32', and extends to the periphery of the first electrode 21, and the annular sacrificial protrusion 32' forms a closed ring to define the range of the effective resonance region by the boundary of the ring-shaped sacrificial protrusion 32'.
  • the formed electrode lead-out structure 3 and the second electrode 23 respectively have a first portion extending outside the effective resonance region to serve as an electrode connection terminal.
  • the conductive material can also be etched to remove the part located in the area surrounded by the annular sacrificial protrusion 32' conductive material, so that the electrode lead-out structure 3 is disconnected inside the area surrounded by the annular sacrificial protrusion 32'.
  • the arch bridge 31 of the electrode lead-out structure is a part of the conductive material formed on the annular sacrificial protrusion 32'.
  • the patterned electrode lead-out structure 3 is also included when forming the electrode lead-out structure 3, and the patterned second electrode 23 is also included when the second electrode 23 is formed, so that the electrode lead-out structure 3 and the second electrode 23 are at least partially around the periphery of the effective resonance region They are staggered from each other to avoid the high frequency coupling problem caused by the existence of potential floating, to prevent the formation of parasitic capacitance, and to improve the quality factor of the resonator.
  • the projections of the electrode lead-out structure 3 and the second electrode 23 on the surface of the piezoelectric layer 22 at the periphery of the effective resonance region are completely staggered, the problem of high frequency coupling can be better avoided.
  • the formed electrode lead-out structure 3 extends from the periphery of the annular gap to the supporting layer on the periphery of the first cavity formed subsequently.
  • the electrode lead-out structure 3 includes an arch bridge 31 and an overlap portion connecting the arch bridge 31 and extending to the periphery of the first cavity 121 or the acoustic mirror 51 .
  • the overlapping portion surrounds part or all of the periphery of the first electrode 21 .
  • a part of the overlap portion extends to the outer edge of the support layer 12 at the periphery of the first cavity 121 , or the entire circumference of the overlap portion extends to the outer edge of the support layer 12 at the periphery of the first cavity 121 , so as to communicate with the outside
  • the structural strength of the resonator is better.
  • the overlapping portion may be a planar structure without being etched, and be laid on the first electrode 21; or, the overlapping portion may be etched to form a plurality of overlapping portions of a strip-shaped structure, and a plurality of overlapping overlapping strips may be formed.
  • the parts can be symmetrically distributed on the first electrode 21, thereby improving the structural strength of the resonator.
  • the impedance of the electrode extraction structure 3 should be lower than that of the first electrode 21 .
  • the material of the electrode extraction structure 3 is a metal material, and the metal material includes one or more of gold, silver, tungsten, platinum, aluminum, copper, titanium, tin, and nickel.
  • the support layer 12 is formed on the first electrode 21 .
  • the support layer 12 may be formed on the first electrode 21 by physical vapor deposition or chemical vapor deposition to cover the first electrode 21 and the electrode lead-out structure 3 .
  • the material of the support layer 12 can be any suitable dielectric material, including but not limited to one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride and other materials, but the technology of the present invention is not limited to this .
  • the support layer 12 is patterned to form a first cavity 121 penetrating the support layer 12.
  • the first cavity 121 exposes at least the arch bridge 31 structure of the electrode lead-out structure 3, so that an effective resonance area is formed in the first cavity 121.
  • the first cavity 121 may be formed by an etching process.
  • the cross-sectional shape of the first cavity 121 may be a rectangle, but in other embodiments of the present invention, the cross-sectional shape of the first cavity 121 may also be a circle, an ellipse, or a polygon other than a rectangle, such as a pentagon , hexagon, etc.
  • the first substrate 11 is formed, and the first substrate 11 covers the first cavity 121 .
  • the first substrate 11 may be bonded to the support layer 12 by means of a bonding layer.
  • the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.
  • the bonding layer can also use adhesives such as light-curing materials or heat-curing materials, such as adhesive film (Die Attach Film, DAF) or dry film (Dry Film), etc.
  • the material of the first substrate 11 may be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), Indium Arsenide (InAs), Gallium Arsenide (GaAs), Indium Phosphide (InP) or other III/V compound semiconductors.
  • the carrier substrate is removed, and the above structure is turned over.
  • the carrier substrate may be removed by a grinding process or a wet etching process, or an isolation layer may be formed on the carrier substrate before the second electrode 23 is formed, and the carrier substrate may be peeled off by removing the isolation layer.
  • the material of the isolation layer includes, but is not limited to, at least one of silicon dioxide, silicon nitride, aluminum oxide, and aluminum nitride, or thermal expansion tape.
  • the annular sacrificial protrusion is removed to form an annular void 32 .
  • a release hole is formed on the second electrode 23 through which the first sacrificial layer material located in the first trench 25 and the annular trench 24 is exposed, and the annular sacrificial protrusion is removed through the release hole.
  • the method for removing the annular sacrificial protrusion includes: forming a first release hole on the second electrode 23 to expose the annular sacrificial protrusion, and removing the annular sacrificial protrusion through the first release hole.
  • a corresponding removal method is adopted according to the material of the annular sacrificial bump.
  • the specific ashing method is that at a temperature of 250 degrees Celsius, oxygen chemically reacts with the sacrificial layer material through the air, and the generated gaseous substances are volatilized.
  • the silicon dioxide reacts to remove to form annular voids 32, which have the same shape as the annular sacrificial protrusions.
  • the formed annular space 32 is a closed annular structure, and the annular space 32 is opposite to the annular groove 24 .
  • the projection of the annular groove 24 on the surface of the piezoelectric layer 22 may partially overlap with the projection of the annular gap 32 on the surface of the piezoelectric layer 22, or the annular groove 24 may overlap the piezoelectric layer 22.
  • the projections of the surface of the piezoelectric layer 22 are all within the projection range of the annular space 32 on the surface of the piezoelectric layer 22 .
  • the effect of preventing sound wave leakage is better.
  • the area enclosed by the annular gap is an effective resonance area, and the first electrode 21 , the piezoelectric layer 22 and the second electrode 23 in the effective resonance area overlap each other on a surface perpendicular to the piezoelectric layer 22 .
  • the method for forming the first electrode 21 , the piezoelectric layer 22 and the second electrode 23 further includes: providing a carrier substrate 4 ; forming the first electrode 21 on the carrier substrate 4 After removing the carrier substrate 4, the piezoelectric layer 22 and the second electrode 23 are sequentially formed on the first electrode 21; Before forming the support layer, an electrode extraction structure is formed on the first electrode 21 .
  • a carrier substrate 4 is provided, and a first electrode 21 is formed on the carrier substrate 4 .
  • the annular groove 24 needs to be formed by etching on the first electrode 21 , so that the arched bridge structure of the electrode lead-out structure 3 is subsequently formed at the opposite position of the annular groove 24 .
  • the annular trench 24 may be formed by etching after the first electrode 21 is formed and before the electrode lead-out structure 3 is formed. In other embodiments, the annular trench 24 may be formed after subsequent removal of the carrier substrate 4 and before the formation of the piezoelectric layer 22 .
  • an electrode lead-out structure 3 is formed on the first electrode 21 ; a support layer 12 is formed; the support layer 12 is etched to form a first cavity 121 penetrating the support layer 12 ; the first substrate 11 is bonded on the support layer 12 , the first substrate 11 covers the first cavity 121 .
  • the specific steps can be referred to as described in Embodiment 1, wherein the annular sacrificial protrusion 32' fills the annular groove and covers the first electrode 21 in the peripheral region of the annular groove.
  • the carrier substrate is removed, the above structure is reversed, and then the piezoelectric layer 22 and the second electrode 23 are sequentially deposited on the first electrode 21 .
  • the piezoelectric layer 22 is etched to form a groove penetrating the piezoelectric layer 22 and the first electrode 21, wherein the part penetrating the first electrode 21 is an annular groove,
  • the part passing through the piezoelectric layer 22 is the first groove, and the annular groove and the projection of the first groove on the surface of the piezoelectric layer 22 completely overlap; flush; and then form a second electrode 23 on the piezoelectric layer 22 .
  • the first electrode 21 is etched to form an annular trench penetrating the first electrode 21 ; the annular trench is filled with sacrificial material so that the upper surface of the annular trench is in contact with the first electrode 21 The surface is flush; then the piezoelectric layer 22 is formed on the first electrode 21, and the piezoelectric layer 22 is etched to form a first trench penetrating the piezoelectric layer 22; the sacrificial material is filled in the first trench to make the upper surface It is flush with the upper surface of the piezoelectric layer 22; the second electrode 23 is formed on the piezoelectric layer 22, and the first groove is opposite to the annular groove, that is, the projection of the first groove on the surface of the piezoelectric layer 22 is the same as the annular groove.
  • the projections on the surface of the piezoelectric layer partially overlap; or, the projection of the first groove on the surface of the piezoelectric layer 22 is completely within the projection range of the annular groove on the surface of the piezoelectric layer. It should be noted that, after the second electrode 23 is formed, the sacrificial material and the annular sacrificial protrusion are removed, and the removal method is referred to in Embodiment 1, and details are not repeated here.
  • the method for forming the first electrode 21 , the piezoelectric layer 22 and the second electrode 23 further includes: providing a carrier substrate 4 ; and sequentially forming the piezoelectric layers on the carrier substrate 4 22. Forming a first electrode 21; after removing the carrier substrate 4, forming a second electrode 23 on the piezoelectric layer 22; forming an electrode lead-out structure 3 on the first electrode 21, including: after forming the first electrode 21, forming Before the support layer, an electrode lead-out structure 3 is formed on the first electrode 21 . Specifically: referring to FIG.
  • a carrier substrate 4 is provided, a piezoelectric layer 22 is formed on the carrier substrate 4, a first electrode 21 is formed on the piezoelectric layer 22, the first electrode 21 and the piezoelectric layer 22 are etched, and the The groove penetrating the first electrode 21 and the piezoelectric layer 22 , wherein the part penetrating the first electrode 21 is the annular groove 24 , and the part penetrating the piezoelectric layer 22 is the first groove 25 .
  • the etching of the annular trench 24 and the first trench 25 may be performed simultaneously or in steps to the piezoelectric layer 22 and the first electrode 21 before the subsequent formation of the second electrode 23 .
  • an electrode lead-out structure 3 and a support layer 12 having a first cavity are formed on the first electrode 21 ; the first substrate 11 is bonded on the support layer 12 .
  • the annular sacrificial protrusion 32' forming the arch bridge structure of the electrode lead-out structure 3 fills the annular groove and the first groove, and covers part of the first electrode 21 in the peripheral region of the annular groove.
  • the carrier substrate is removed, and the above structure is reversed, and the second electrode 23 is deposited on the piezoelectric layer 22 .
  • the annular sacrificial protrusion forming the annular space 31 of the electrode lead-out structure 3 may be removed first.
  • the electrode lead-out structure is not formed on the first electrode 21
  • the electrode lead-out structure 3 is formed on the second electrode 23 , and the formation steps can refer to the above steps and Embodiment 1, and are not repeated here.
  • the electrode extraction structure 3 when the first electrode 21 is not provided with the electrode extraction structure 3, the electrode extraction structure 3 needs to be formed on the second electrode 23, and the process of forming the electrode extraction structure 3 on the second electrode is omitted, and Embodiment 4 is omitted.
  • the annular groove 24 and the electrode lead-out structure 3 on the first electrode 21 and after the second electrode 23 is formed the annular groove and the electrode lead-out structure are formed on the second electrode 23.
  • the formation process can be referred to in The process of forming the electrode extraction structure 3 on the first electrode 21 will not be repeated here.
  • the first trench 25 may be formed when the annular trench 24 penetrating the second electrode 23 is formed, or may be formed after the piezoelectric layer 22 is formed and before the second electrode 23 is formed.
  • the sacrificial layer material needs to be filled in the first trench 25 now, so that the upper surface of the first trench 25 is kept flat with the surface of the piezoelectric layer 22, and then the first trench 25 is formed. Two electrodes 23 .
  • Embodiment 2 provides a method for manufacturing a thin-film bulk acoustic resonator.
  • FIG. 12 is a schematic structural diagram of a thin-film bulk acoustic resonator manufactured according to the method for manufacturing a thin-film bulk acoustic resonator in this embodiment. The difference is that the piezoelectric layer 22 in the first embodiment is formed with the first groove 25, and the piezoelectric layer 22 in this embodiment is a complete film layer, and the etching of the piezoelectric layer 22 in the above-mentioned embodiment 1 is omitted. For this step, the remaining steps refer to Example 1 above. Specifically, the piezoelectric layer 22 is a complete film layer without etching, covering the first cavity 121 and extending to the first substrate 11 outside the first cavity 121 to ensure the structural strength of the resonator and improve the Resonator yield.
  • Embodiment 3 provides a method for manufacturing a thin-film bulk acoustic resonator.
  • Figures 13-19 are schematic structural diagrams of a thin-film bulk acoustic resonator manufactured according to the method for manufacturing a thin-film bulk acoustic resonator in this embodiment.
  • the difference between 1 and 1 is that in Embodiment 1, one of the first electrode 21 and the second electrode 23 is provided with an electrode extraction structure 3 , and in this embodiment, both the first electrode 21 and the second electrode 24 are provided with an electrode extraction structure 3 .
  • the specific steps are: forming the second electrode 23 , forming the piezoelectric layer 22 , and forming the first electrode 21 on the carrier substrate 4 in sequence; etching the first electrode 21 , A groove is formed through the first electrode 21, the piezoelectric layer 22 and the second electrode 23, wherein the part passing through the first electrode 21 and the second electrode 23 is an annular groove; the part passing through the piezoelectric layer 22 is the first groove Slot 25, see FIG. 13 .
  • the first sacrificial material when the first sacrificial material is deposited on the first electrode 21 to form an annular sacrificial protrusion, the first sacrificial material fills the trench and covers the first electrode 21 in the peripheral region of the trench, and then forms a covering annular shape on the first electrode 21 .
  • Sacrificial raised electrode extraction structure 3 refer to FIG. 14 .
  • a support layer 12 is formed on the first electrode 21; the support layer 12 is etched to form a first cavity 121 penetrating the support layer 12; a first substrate 11 is provided to cover the first cavity 121; the carrier substrate 4 is removed, and the Invert the above structure.
  • annular sacrificial bump is formed on the second electrode 21 , the annular sacrificial bump is connected to the annular sacrificial bump and covers part of the surface of the second electrode 23 , and then an electrode covering the annular sacrificial bump is formed on the second electrode 23
  • the sacrificial material is removed.
  • forming the electrode lead-out structure 3 on the first electrode 21 also includes patterning the electrode lead-out structure
  • forming the electrode lead-out structure 3 on the second electrode 23 also includes patterning the electrode lead-out structure, so that the electrode lead-out structure formed on the first electrode 23 also includes patterning.
  • the electrode lead-out structure 3 on the electrode 21 and the electrode lead-out structure 3 formed on the second electrode 23 are at least partially offset from each other at the periphery of the annular gap, that is, at the periphery of the annular gap, the electrode lead-out structure 3 formed on the first electrode 21 and
  • the projection of the electrode lead-out structure 3 formed on the second electrode 23 on the surface of the piezoelectric layer 22 does not overlap at least in part, so as to avoid the problem of high-frequency coupling caused by the existence of potential floating, prevent the formation of parasitic capacitance, and help improve the quality of the resonator factor.
  • the electrode lead-out structure 3 formed on the first electrode 21 and the electrode lead-out structure 3 formed on the second electrode 23 are completely offset from each other at the periphery of the annular gap, the problem of high frequency coupling can be better avoided.
  • the arch bridge 31 of the electrode lead-out structure 3 formed on the first electrode 21 and the arch bridge 31 of the electrode lead-out structure 3 formed on the second electrode 23 The structures are arranged oppositely, that is, the projection of the arched bridge 31 structure formed on the first electrode 21 and the arched bridge 31 structure formed on the second electrode 23 on the surface of the piezoelectric layer 22 overlap each other, so that the The effective resonance area enclosed by the annular gap is the same area.
  • the electrode lead-out structure 3 disposed on the first electrode 21 and the electrode lead-out structure 3 disposed on the second electrode 23 respectively have a second portion extending outside the effective resonance area as an electrode connection terminal.
  • the steps of the above-mentioned Embodiment 4 are performed, and the second electrode 23 is etched after removing the substrate and before removing the annular sacrificial bump on the first electrode 21 . , forming an annular groove penetrating the second electrode 23 , referring to FIG. 16 .
  • An annular sacrificial protrusion is formed on the second electrode 23 , covering the first sacrificial material and partially covering the second electrode 23 , and an electrode lead-out structure 3 covering the annular sacrificial protrusion is formed on the second electrode 23 , referring to FIG. 17 .
  • the first sacrificial material and the annular sacrificial bump are removed.
  • the specific formation process corresponding to the above steps and the remaining steps of the thin film bulk acoustic wave resonator refer to Embodiment 1, and are not repeated here.
  • a second electrode 23, a piezoelectric layer 22, and a first electrode 21 are formed in sequence on the carrier substrate 4; an electrode lead-out structure is formed on the first electrode 21, refer to Figure 18.
  • Embodiment 1 For the specific formation process of the above steps, refer to Embodiment 1, which will not be repeated here.
  • Embodiment 4 provides a method for manufacturing a thin-film bulk acoustic resonator.
  • FIG. 20 is a schematic structural diagram of a thin-film bulk acoustic resonator manufactured according to the method for manufacturing a thin-film bulk acoustic resonator in this embodiment. The difference is that the piezoelectric layer 22 in Embodiment 3 is formed with the first trench 25, and the piezoelectric layer 22 in this embodiment is not etched to form the first trench 25, which is a complete film layer, and the above embodiment is omitted.
  • the step of etching the piezoelectric layer 22 in 3 the rest of the steps refer to Embodiment 3 above.
  • the beneficial effect of the piezoelectric layer 22 being a complete film layer reference may be made to the above-mentioned Embodiment 2, which will not be repeated here.
  • the first electrode 21 and the second electrode 23 are both provided with the electrode lead-out structure 3 , the electrode lead-out structure provided on the first electrode 21 and the electrode lead-out structure provided on the second electrode 23
  • the periphery of the annular gap is at least partially staggered from each other, so as to avoid the problem of high-frequency coupling caused by the floating potential, and prevent the formation of parasitic capacitance, thereby improving the quality factor of the resonator.
  • the electrode lead-out structure disposed on the first electrode 21 and the electrode lead-out structure disposed on the second electrode 23 are completely staggered at the periphery of the annular gap, the problem of high frequency coupling can be better avoided.
  • the structure of the electrode lead-out structure 3 and the relative relationship between it and the corresponding electrodes and between the support layers can be referred to in Embodiment 1, which will not be repeated here.
  • Embodiment 5 of the present invention provides a filter, comprising at least one thin-film bulk acoustic resonator manufactured by the above method.
  • a filter is formed by connecting the above-mentioned thin film bulk acoustic wave resonators to ensure that the filter has good structural stability, and because the electrode impedance of the resonator is low, the conductivity of the filter can be improved, and the filtering accuracy can be improved.

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Abstract

本发明涉及一种薄膜体声波谐振器的制造方法及滤波器，包括：形成第一电极、压电层和第二电极；在第一电极、第二电极至少其中之一上形成贯穿相应电极的环形沟槽；在具有环形沟槽的电极上形成具有拱形桥的电极引出结构；在第一电极上形成支撑层；图形化支撑层，形成贯穿支撑层的第一空腔，电极引出结构的拱形桥位于第一空腔范围内；提供第一衬底，遮盖第一空腔；去除环形牺牲凸起形成环形空隙，环形空隙和环形沟槽相对。本发明通过电极引出结构的环形空隙所在的区域界定有效谐振区的边界，并通过环形沟槽使有效谐振区边界处相应电极的端部与空隙的气体接触，从而达到消除有效谐振区的电极的边界杂波的效果，进而提升谐振器的Q值。

Description

薄膜体声波谐振器的制造方法及滤波器 技术领域
本发明涉及半导体器件制造领域，尤其涉及一种薄膜体声波谐振器的制造方法及滤波器。
 背景技术
自模拟射频通讯技术在上世纪90代初被开发以来，射频前端模块已经逐渐成为通讯设备的核心组件。在所有射频前端模块中，滤波器已成为增长势头最猛、发展前景最大的部件。随着无线通讯技术的高速发展，5G通讯协议日渐成熟，市场对射频滤波器的各方面性能也提出了更为严格的标准。滤波器的性能由组成滤波器的谐振器单元决定。在现有的滤波器中，薄膜体声波谐振器(FBAR)因其体积小、插入损耗低、带外抑制大、品质因数高、工作频率高、功率容量大以及抗静电冲击能力良好等特点，成为最适合5G应用的滤波器之一。
通常，薄膜体声波谐振器包括两个薄膜电极，并且两个薄膜电极之间设有压电薄膜层，其工作原理为利用压电薄膜层在交变电场下产生振动，该振动激励出沿压电薄膜层厚度方向传播的体声波，此声波传至上下电极与空气交界面被反射回来，进而在薄膜内部来回反射，形成震荡。当声波在压电薄膜层中传播正好是半波长的奇数倍时，形成驻波震荡。
 技术问题
但是，目前制作出的空腔型薄膜体声波谐振器，其品质因子（Q）无法进一步提高，因此无法满足高性能的射频系统的需求。
 技术解决方案
本发明的目的在于提供一种薄膜体声波谐振器的制造方法及滤波器，能够提高薄膜体声波谐振器的品质因子，进而提高器件性能。
为了实现上述目的，本发明提供了一种薄膜体声波谐振器的制造方法，包括：形成第一电极、压电层和第二电极，压电层位于第一电极和第二电极之间，第一电极、第二电极至少其中之一形成贯穿相应电极的环形沟槽；在具有环形沟槽的电极上形成具有拱形桥的电极引出结构，包括：形成环形牺牲凸起；形成覆盖环形牺牲凸起、边缘搭接在有效谐振区电极边缘上的电极引出结构；在第一电极上形成支撑层；图形化支撑层，形成贯穿支撑层的第一空腔；提供第一衬底，第一衬底遮盖第一空腔，电极引出结构的拱形桥位于第一空腔范围内；去除环形牺牲凸起形成环形空隙，环形空隙和环形沟槽相对。
本发明还提供了一种滤波器，包括至少一个如上所述的薄膜体声波谐振器的制造方法形成的薄膜体声波谐振器。
 有益效果
本发明的薄膜体声波谐振器的制造方法的有益效果在于：通过在相应电极上形成环形牺牲凸起的方式形成具有拱形桥结构电极引出结构，并在去除环形牺牲凸起后，形成环形空隙，以界定有效谐振区的范围，再通过刻蚀相应电极形成贯穿相应电极的环形沟槽，既便于简化电极引出结构的形成工艺，又可以将位于环形沟槽内、外的电极分离，并通过电极引出结构将被断开的电极电连。另外，通过环形沟槽使相应电极的边界暴露于拱形桥形成的环形空隙中，从而达到消除有效谐振区的电极边界杂波的效果，进而提升谐振器的Q值。
进一步地，通过刻蚀支撑层的方式形成第一空腔，可以简化形成工艺，减少制造成本。
进一步地，将压电层形成在平整的电极或承载衬底上，使得压电层的上表面和下表面均为平面，保证压电层具有较好的晶格取向，提高压电层的压电特性，进而提高谐振器的性能。
进一步地，电极引出结构的阻抗低于相应电极的阻抗，以降低电极阻抗，使电极引出结构具有较好的导电性，提高导电率。
进一步地，电极引出结构与未设有电极引出结构的相应电极或分别设于第一电极、第二电极上的电极引出结构在拱形桥外围区域至少部分相互错开，可以避免由于电位浮空产生的高频耦合问题，防止形成寄生电容，有利于提高谐振器品质因数。
进一步地，第一电极和/或第二电极从有效谐振区延伸至第一空腔外围的第一衬底上，可以提高谐振器的结构强度，另外，形成于相应电极上的电极引出结构也从有效谐振区延伸至第一空腔外围的第一衬底上，以提高谐振器的结构强度。
进一步地，压电层为完整的膜层，可以保障谐振器的结构强度，提高谐振器的成品率。
进一步地，压电层中设有第一沟槽，使压电层的边缘暴露在气体中，能够抑制压电层的横波损失，当第一沟槽全部位于环形空隙范围内时，可以更好的提升谐振器的Q值。
本发明的滤波器的有益效果在于：通过上述薄膜体声波谐振器连接形成滤波器，以确保该滤波器具有较好的结构稳定性，且由于谐振器的电极阻抗较低，可以提高滤波器的导电率，提高滤波的准确性。
 附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明实施例1的薄膜体声波谐振器的制造方法的流程图；图2至图5示出了本发明实施例1的薄膜体声波谐振器的制造方法不同步骤对应的结构示意图；图6至图8示出了本发明实施例1中形成的薄膜体声波谐振器的另一制造方法不同步骤对应的结构示意图；图9至图11示出了本发明实施例1中形成的薄膜体声波谐振器的另一制造方法不同步骤对应的结构示意图；图12为根据实施例2薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图；图13-19为根据实施例3薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图；图20为根据实施例4薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图。
附图标记说明： 11、第一衬底；12、支撑层；121、第一空腔；21、第一电极；22、压电层；23、第二电极；24、环形沟槽；25、第一沟槽；3、电极引出结构；31、拱形桥；32、环形空隙；32’、环形牺牲凸起；4、承载衬底；5、第二衬底；51、声反射镜。
 本发明的实施方式
以下结合附图和具体实施例对本发明的薄膜体声波谐振器及其制作方法作进一步详细说明。根据下面的说明和附图，本发明的优点和特征将更清楚，然而，需说明的是，本发明技术方案的构思可按照多种不同的形式实施，并不局限于在此阐述的特定实施例。附图均采用非常简化的形式且均使用非精准的比例，仅用以方便、明晰地辅助说明本发明实施例的目的。
在说明书和权利要求书中的术语“第一”“第二”等用于在类似要素之间进行区分，且未必是用于描述特定次序或时间顺序。要理解，在适当情况下，如此使用的这些术语可替换，例如可使得本文所述的本发明实施例能够以不同于本文所述的或所示的其他顺序来操作。类似的，如果本文所述的方法包括一系列步骤，且本文所呈现的这些步骤的顺序并非必须是可执行这些步骤的唯一顺序，且一些所述的步骤可被省略和/或一些本文未描述的其他步骤可被添加到该方法。若某附图中的构件与其他附图中的构件相同，虽然在所有附图中都可轻易辨认出这些构件，但为了使附图的说明更为清楚，本说明书不会将所有相同构件的标号标于每一图中。
实施例 1
图1为本发明实施例1的薄膜体声波谐振器的制造方法的流程图，参照图1，实施例1提供了一种薄膜体声波谐振器的制造方法，薄膜体声波谐振器的制造方法包括：S01：形成第一电极、压电层和第二电极，压电层位于第一电极和第二电极之间；S02：在第一电极、第二电极至少其中之一上形成贯穿相应电极的环形沟槽；S03：在具有环形沟槽的电极上形成具有拱形桥的电极引出结构，包括：形成环形牺牲凸起；形成覆盖环形牺牲凸起、边缘搭接在有效谐振区电极边缘上的电极引出结构；S04：在第一电极上形成支撑层；图形化支撑层，形成贯穿支撑层的第一空腔，电极引出结构的拱形桥位于第一空腔范围内；S05：提供第一衬底，第一衬底遮盖第一空腔；S06：去除环形牺牲凸起形成环形空隙，环形空隙和环形沟槽相对。
步骤S0N不代表先后顺序。
第一电极21、第二电极24中的一个设置电极引出结构，以下以在第一电极31上形成电极引出结构为例，对该薄膜体声波谐振器的制造方法进行说明，图2至图5为本实施例的一种薄膜体声波谐振器的制造方法的相应步骤对应的结构示意图，参考图2至5详细说明本实施例提供的薄膜体声波谐振器的制造方法。
参考图2至图5，本实施例中，形成第一电极21、压电层22和第二电极24的方法包括：提供承载衬底4；在承载衬底4上依次形成第二电极23、形成压电层22和形成第一电极21；在第一衬底11遮盖支撑层12上的第一空腔121后，去除承载衬底4；在第一电极上形成电极引出结构，具体包括：在形成第一电极后、形成支撑层之前，在第一电极上形成电极引出结构。
参考图2，提供承载衬底4，承载衬底4可以为半导体材料，如硅(Si)、锗(Ge)、锗硅(SiGe)、碳硅(SiC)、碳锗硅(SiGeC)、砷化铟(InAs)、砷化镓(GaAs)、磷化铟(InP)或者其它III/V化合物半导体。
继续参考图2，依次在承载衬底4上形成第二电极23、形成压电层22和形成第一电极21，其中第一电极21和第二电极23可以通过物理气相沉积工艺和刻蚀工艺形成，第一电极21和/或第二电极23的四周延伸至后续形成的第一空腔外围的支撑层12上，以提高谐振器的结构强度，当第一电极21和第二电极23均从有效谐振区延伸至第一空腔121或声反射镜51外围的第一衬底1上时，谐振器结构强度较佳。压电层22可以使用化学气相沉积、物理气相沉积或原子层沉积等本领域技术人员熟知的任何适合的方法沉积形成。通过将压电层22形成在平整的第二电极23上，使压电层22的上表面和下表面均为平面，从而确保压电层22具有较好的晶格取向，提高压电层22的压电特性，进而提高谐振器的整体性能。需要说明的是，第一电极21的四周为其整体结构的外边缘，第二电极23的四周为其整体结构的外边缘，有效谐振区为后续形成的环形空隙围成的区域。
在其他实施例中，在形成第一电极21和/或形成第二电极23时，还可以刻蚀相应电极，使第一电极21和/或第二电极23的部分四周延伸至第一空腔外围的支撑层12上，此时，为保证谐振器的结构强度，部分延伸至第一空腔121外围第一衬底1上的电极对称分布，以确保支撑强度，从而使得该电极遮盖部分或全部第一空腔。
第一电极21和第二电极23的材料可以使用本领域技术任意熟知的任意合适的导电材料或半导体材料，其中，导电材料可以为具有导电性能的金属材料，例如，由钼（Mo）、铝（Al）、铜（Cu）、钨（W）、钽（Ta）、铂（Pt）、钌（Ru）、铑（Rh）、铱（Ir）、铬（Cr）、钛（Ti）、金(Au)、锇(Os)、铼(Re)、钯(Pd)等金属中一种制成或由上述金属形成的叠层制成，所述半导体材料例如是Si、Ge、SiGe、SiC、SiGeC等。压电层22的材料可以使用氮化铝(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)等具有纤锌矿型结晶结构的压电材料及它们的组合。当压电层22材料为氮化铝(AlN)时，压电层22还可包括稀土金属，例如钪(Sc)、铒(Er)、钇(Y)和镧(La)中的至少一种。此外，当压电层22的材料为氮化铝(AlN)时，压电层22还可包括过渡金属，例如锆(Zr)、钛(Ti)、锰(Mn)和铪(Hf)中的至少一种。
继续参照图2，在形成环形牺牲凸起之前，刻蚀第一电极21形成环形沟槽24，环形沟槽24为封闭的环形，以使第一电极21在环形沟槽24位置处被断开，从而便于通过后续形成的电极引出结构3将被断开的第一电极21连接起来，由于后续形成的电极引出结构3的阻抗低于第一电极21的阻抗，因此可以降低第一电极21的阻抗。另外，环形沟槽24还可以使第一电极21的边界被暴露于后续形成的环形空隙32中，从而达到消除有效谐振区的电极边界杂波的效果，进而提升谐振器的Q值。有效谐振区为后续形成的电极引出结构的拱形桥结构形成的环形空隙所围区域。
在本实施例中，在刻蚀形成环形沟槽24的过程中，还可以对压电层22进行刻蚀，形成贯穿压电层22的第一沟槽25，通过第一沟槽25贯穿压电层22，使压电层22的端面与第一沟槽25中的气体形成反射界面，进而有效抑制压电层22中的声波泄露，并避免发生寄生谐振，提高谐振器的品质因数。在其他实施例中，还可以在形成压电层22后，对压电层22刻蚀形成第一沟槽25，再在第一沟槽25内填充牺牲材料，使其上表面与压电层22上表面齐平，再在其上形成第一电极21，刻蚀第一电极21形成环形沟槽，去除填充于第一沟槽25内的牺牲材料，使得形成的环形沟槽24与第一沟槽25相对。
具体地，第一沟槽25在压电层22表面的投影可以与环形沟槽24在压电层22表面的投影部分重叠，或，第一沟槽25在压电层22表面的投影完全位于环形沟槽24在压电层22表面的投影范围内。在本实施例中，当第一沟槽25和环形沟槽24同步形成时，第一沟槽25在压电层22表面的投影与环形沟槽24在压电层22表面的投影完全重叠，此时声波抑制效果较好。另外，第一沟槽25为封闭的环形，环形空隙32内围的压电层22和环形空隙32外围的压电层22相互隔离；或者，第一沟槽25为间断的环形，环形空隙32内围的压电层32通过间断处与环形空隙32外围的压电层相互隔离。当第一沟槽25为封闭的环形时，抑制声波效果较好。
参照图3，在第一电极21上沉积形第一牺牲材料，第一牺牲材料填充环形沟槽和第一沟槽且覆盖部分位于环形沟槽周边区域的第一电极21，第一牺牲层材料包括磷硅玻璃、低温二氧化硅、硼磷硅玻璃、锗、非晶碳、聚酰亚胺或光阻剂。图形化位于第一电极21上的第一牺牲层材料形成环形牺牲凸起32’，环形牺牲凸起32’为连续的结构，围成封闭的环形，并通过该环形的边界界定谐振器有效谐振区的边界。
继续参照图3，在第一电极21上形成覆盖环形牺牲凸起32’、边缘搭接在有效谐振区第一电极21边缘上的电极引出结构3，具体包括：在第一电极21上沉积导电材料，形成电极引出结构3，电极引出结构3覆盖第一电极21和形成于第一电极21上的环形牺牲凸起32’，并延伸至第一空腔外围的支撑层12上。需要说明的是，沉积的导电材料覆盖部分第一电极21和环形牺牲凸起32’和环形牺牲凸起32’外周的第一电极21，并延伸至第一电极21的四周，环形牺牲凸起32’围成封闭的环形，以通过环形牺牲凸起32’的边界界定有效谐振区的范围。另外，形成的电极引出结构3和第二电极23分别具有延伸至有效谐振区外的第一部分，以作为电极连接端。
在实际制作过程中，由于电极引出结构3仅需连接被环形沟槽断开的第一电极21，因此，还可以刻蚀导电材料，以去除位于环形牺牲凸起32’围成区域内的部分导电材料，以使电极引出结构3在环形牺牲凸起32’围成的区域内部断开。需要说明的是，电极引出结构的拱形桥31结构为形成于环形牺牲凸起32’上导电材料的部分。在形成电极引出结构3时还包括图形化电极引出结构3，在形成第二电极23时还包括图形化第二电极23，以使电极引出结构3与第二电极23在有效谐振区外围至少部分相互错开，以避免由于存在电位浮空产生的高频耦合问题，防止形成寄生电容，有利于提高谐振器品质因数。当有效谐振区外围的电极引出结构3和第二电极23在压电层22表面的投影完全错开时，可以较好的避免高频耦合问题。
在本实施例中，形成的电极引出结构3从环形空隙的四周延伸至后续形成的第一空腔外围的支撑层上。具体地，电极引出结构3包括拱形桥31和连接拱形桥31并延伸至第一空腔121或声反射镜51外围的搭接部，拱形桥31的四周搭接在有效谐振区第一电极21的边缘上，搭接部环绕第一电极21的部分外周或全部外周。换言之，搭接部的部分四周延伸至第一空腔121外围的支撑层12的外边缘，或搭接部的四周全部延伸至第一空腔121外围的支撑层12的外边缘，以与外部电连，当搭接部的四周全部延伸至第一空腔121外围的支撑层12的外边缘时，谐振器的结构强度较好。搭接部可以不经刻蚀，为面状结构，铺设于第一电极21上；或，搭接部可以经刻蚀，以形成多个条状结构的搭接部，多个条状搭接部可以对称分布于第一电极21上，从而提高谐振器的结构强度。
应当注意，为降低第一电极21的阻抗，电极引出结构3的阻抗应当低于第一电极21的阻抗。电极引出结构3的材料为金属材料，所述金属材料包括金、银、钨、铂、铝、铜、钛、锡、镍中的一种或多种。
参照图4，在第一电极21上形成支撑层12。在本实施例中，支撑层12可以通过物理气相沉积或化学气相沉积的方式形成于第一电极21上，以覆盖第一电极21和电极引出结构3。支撑层12的材料可以是任意适合的介电材料，包括但不限于氧化硅、氮化硅、氮氧化硅、碳氮化硅等材料中的一种，但本发明的技术不仅仅限定于此。
继续参照图4，图形化支撑层12，形成贯穿支撑层12的第一空腔121，第一空腔121至少暴露电极引出结构3的拱形桥31结构，以使有效谐振区形成于第一空腔121上方，进而便于位于有效谐振区内且在第一电极21、第二电极23之间传递的声波通过第一空腔121内的气体界面被反射回来，从而提高声波利用率。在本实施例中，第一空腔121可以通过刻蚀的工艺形成。第一空腔121的截面形状为可以为矩形，但在本发明的其他实施例中，第一空腔121的截面形状还可以是圆形、椭圆形或是矩形以外的多边形，例如五边形、六边形等。
继续参照图4，形成第一衬底11，第一衬底11遮盖第一空腔121。在本实施例中，第一衬底11可以通过键合层的方式键合于支撑层12上。键合层的材料包括氧化硅、氮化硅、氮氧化硅、碳氮化硅或硅酸乙酯。此外，键合层还可以采用光固化材料或热固化材料等黏结剂，例如粘片膜（Die Attach Film，DAF）或干膜（Dry Film）等。第一衬底11的材料可以为以下所提到的材料中的至少一种：硅(Si)、锗(Ge)、锗硅(SiGe)、碳硅(SiC)、碳锗硅(SiGeC)、砷化铟(InAs)、砷化镓(GaAs)、磷化铟(InP)或者其它III/V化合物半导体。
参照图5，去除承载衬底，并将上述结构翻转。可以通过研磨工艺或者湿法腐蚀工艺去除承载衬底，也可以在形成第二电极23之前在承载衬底上形成隔离层，通过去除隔离层的方式剥离承载衬底。隔离层的材质包括但不限于二氧化硅、氮化硅、氧化铝和氮化铝中或热膨胀胶带中的至少一种。
继续参照图5，去除环形牺牲凸起形成环形空隙32。具体为，在第二电极23上形成贯穿第二电极23露出位于第一沟槽25和环形沟槽24内的第一牺牲层材料的释放孔，通过释放孔去除环形牺牲凸起。去除环形牺牲凸起的方法包括：在第二电极23上形成暴露环形牺牲凸起的第一释放孔，通过第一释放孔去除环形牺牲凸起。在去除环形牺牲凸起的过程中，根据环形牺牲凸起的材料，采用相对应的去除方法，比如当环形牺牲凸起材料为聚酰亚胺或光阻剂时，采用灰化的方法去除，灰化的方法具体为在250摄氏度的温度下，氧气通过空气与牺牲层材料发生化学反应，生成气体物质挥发掉，当环形牺牲凸起材料为低温二氧化硅时，用氢氟酸溶剂和低温二氧化硅发生反应去除，以形成环形空隙32，环形空隙32的形状与环形牺牲凸起的形状相同。
在本实施例中，形成的环形空隙32为封闭的环形结构，且环形空隙32与环形沟槽24相对。当环形沟槽24与环形空隙32的相对时，环形沟槽24在压电层22表面的投影可以与环形空隙32在压电层22表面的投影部分重叠，或环形沟槽24在压电层22表面的投影全部位于环形空隙32在压电层22表面的投影范围内。当环形沟槽24在压电层22表面的投影全部位于环形空隙32在压电层22表面的投影范围内时，防止声波泄露效果较好。另外，环形空隙围成的区域为有效谐振区，有效谐振区内的第一电极21、压电层22和第二电极23在垂直于压电层22表面上相互重叠。
在另一实施例中，参照图6-8，形成第一电极21、压电层22和第二电极23的方法还包括：提供承载衬底4；在承载衬底4上形成第一电极21；去除承载衬底4后，依次在第一电极21上形成压电层22、形成第二电极23；在第一电极21上形成所述电极引出结构，包括：在形成第一电极21后、形成支撑层之前，在第一电极21上形成电极引出结构。具体为：参照图6，提供承载衬底4，在承载衬底4上形成第一电极21。需要注意的是，需要在第一电极21上刻蚀形成环形沟槽24，以便于后续在环形沟槽24相对的位置形成电极引出结构3的拱形桥结构。在本实施例中，环形沟槽24可以在形成第一电极21后、形成电极引出结构3之前通过刻蚀形成。在其他实施例中，环形沟槽24可以在后续去除承载衬底4之后、形成压电层22之前形成。
参照图7，在第一电极21上形成电极引出结构3；形成支撑层12；刻蚀支撑层12形成贯穿支撑层12的第一空腔121；在支撑层12上键合第一衬底11，第一衬底11遮盖第一空腔121。其具体步骤可参照实施例1所述，其中，环形牺牲凸起32’填充环形沟槽并覆盖环形沟槽周边区域的第一电极21。
参照图8，去除承载衬底，并翻转上述结构，再依次在第一电极21上沉积形成压电层22和第二电极23。在本实施例中，在形成压电层22后，刻蚀压电层22，形成贯穿压电层22和第一电极21的沟槽，其中，贯穿第一电极21的部分为环形沟槽，贯穿压电层22的部分为第一沟槽，环形沟槽与第一沟槽在压电层22表面的投影完全重叠；在沟槽内填充牺牲材料，使其上表面与压电层22表面齐平；再在压电层22上形成第二电极23。在其他实施例中，在形成压电层22之前，刻蚀第一电极21形成贯穿第一电极21的环形沟槽；在环形沟槽内填充牺牲材料，使其上表面与第一电极21上表面齐平；再在第一电极21上形成压电层22，并刻蚀压电层22形成贯穿压电层22的第一沟槽；在第一沟槽内填充牺牲材料，使其上表面与压电层22上表面齐平；再在压电层22上形成第二电极23，第一沟槽与环形沟槽相对，即第一沟槽在压电层22表面的投影与环形沟槽在压电层表面的投影部分重叠；或，第一沟槽在压电层22表面的投影完全位于环形沟槽在压电层表面的投影范围内。需要注意的是，在形成第二电极23之后，去除牺牲材料和环形牺牲凸起，其去除方法参照实施例1，此处不再赘述。
在另一实施例中，参照图9-11，形成第一电极21、压电层22和第二电极23的方法还包括：提供承载衬底4；在承载衬底4上依次形成压电层22、形成第一电极21；去除承载衬底4后，在压电层22上形成第二电极23；在第一电极21上形成电极引出结构3，包括：在形成第一电21后、形成支撑层之前，在第一电极21上形成电极引出结构3。具体为：参照图9，提供承载衬底4，在承载衬底4上形成压电层22，在压电层22上形成第一电极21，刻蚀第一电极21和压电层22，形成贯穿第一电极21和压电层22的沟槽，其中贯穿第一电极21的部分为环形沟槽24，贯穿压电层22的部分为第一沟槽25。在其他实施例中，环形沟槽24和第一沟槽25的刻蚀可以在后续形成第二电极23之前对压电层22和第一电极21同步或分步进行刻蚀。
参照图10，在第一电极21上形成电极引出结构3和具有第一空腔的支撑层12；在支撑层12上键合第一衬底11。具体步骤可参照实施例1所述，此处不再赘述。其中，形成电极引出结构3拱形桥结构的环形牺牲凸起32’填充环形沟槽和第一沟槽，并覆盖环形沟槽周边区域的部分第一电极21。
参照图11，去除承载衬底，并翻转上述结构，在压电层22上沉积形成第二电极23。需要注意的是，在形成第二电极23之前，可以先去除形成电极引出结构3的环形空隙31结构的环形牺牲凸起。
当第一电极21上未形成电极引出结构时，在第二电极23上形成电极引出结构3，其形成步骤可参照上述步骤和实施例1，此处不再赘述。
在其他实施例中，当第一电极21未设置电极引出结构3时，需要在第二电极23上形成电极引出结构3，在第二电极上形成电极引出结构3的过程，省去实施例4中在第一电极21上形成环形沟槽24和电极引出结构3的步骤，并在形成第二电极23后，在第二电极23上形成环形沟槽和电极引出结构，其形成过程可参照在第一电极21上形成电极引出结构3的过程，此处不再赘述。需要注意的是，在此过程中，第一沟槽25可以在形成贯穿第二电极23的环形沟槽24时形成，也可以在形成压电层22之后、形成第二电极23之前形成，当第一沟槽在形成压电层22之后、形成第二电极23之前形成时，需要现在第一沟槽25内填充牺牲层材料，使其上表面与压电层22表面保持平整，再形成第二电极23。
实施例 2
实施例2提供了一种薄膜体声波谐振器的制造方法，图12为根据本实施例薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图，本实施例与实施例1的区别在于，实施例1中的压电层22形成有第一沟槽25，本实施例中的压电层22为完整的膜层，省去上述实施例1中对压电层22的刻蚀这一步骤，其余步骤参照上述实施例1。具体为：压电层22不经过刻蚀，为完整的膜层，遮盖第一空腔121且延伸至第一空腔121外的第一衬底11上，以保证谐振器的结构强度，提高谐振器的成品率。
实施例 3
实施例3提供了一种薄膜体声波谐振器的制造方法，图13-19为根据本实施例薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图，本实施例与实施例1的区别在于，实施例1中第一电极21、第二电极23中的一个设有电极引出结构3，本实施例中第一电极21和第二电极24均设有电极引出结构3。具体为：在本实施例中，参照图13-15，具体为：在承载衬底4上依次形成第二电极23、形成压电层22、形成第一电极21；刻蚀第一电极21，形成贯穿第一电极21、压电层22和第二电极23的沟槽，其中，贯穿第一电极21和第二电极23的部分为环形沟槽；贯穿压电层22的部分为第一沟槽25，参照图13。相应的，在第一电极21上沉积第一牺牲材料形成环形牺牲凸起时，第一牺牲材料填充沟槽并覆盖沟槽周边区域的第一电极21，再在第一电极21上形成覆盖环形牺牲凸起的电极引出结构3，参照图14。再在第一电极21上形成支撑层12；刻蚀支撑层12形成贯穿支撑层12的第一空腔121；提供第一衬底11，遮盖第一空腔121；去除承载衬底4，并翻转上述结构。在第二电极21上形成另一环形牺牲凸起，该环形牺牲凸起连接上述环形牺牲凸起并覆盖部分第二电极23表面，再在第二电极23上形成覆盖该环形牺牲凸起的电极引出结构3，参照图15。最后，去除牺牲材料。上述步骤的具体形成过程以及该薄膜体声波谐振器的其余步骤参照上述实施例1，此处不再赘述。
应当注意，在第一电极21上形成电极引出结构3时还包括图形化该电极引出结构，在第二电极23上形成电极引出结构3时还包括图形化该电极引出结构，使形成于第一电极21上的电极引出结构3和形成于第二电极23上的电极引出结构3至少部分在环形空隙的外围相互错开，即在环形空隙外围，形成于第一电极21上的电极引出结构3与形成于第二电极23上的电极引出结构3在压电层22表面的投影至少部分不重叠，以避免由于存在电位浮空产生的高频耦合问题，防止形成寄生电容，有利于提高谐振器品质因数。当形成于第一电极21上的电极引出结构3和形成于第二电极23上的电极引出结构3在环形空隙的外围完全相互错开时，可以较好的避免高频耦合问题。
由于环形空隙32围成的区域为有效谐振区，因此形成于第一电极21上的电极引出结构3的拱形桥31结构与形成于第二电极23上的电极引出结构3的拱形桥31结构相对设置，即形成于第一电极21上的拱形桥31结构与形成于第二电极23上的拱形桥31结构在压电层22表面的投影相处重叠，使得两拱形桥内的环形空隙围成的有效谐振区为同一区域。另外，设置于第一电极21上的电极引出结构3和设置于第二电极23上的电极引出结构3分别具有延伸至有效谐振区外的第二部分，以作为电极连接端。
在另一实施例中，参照图16-17，执行上述实施例4的步骤，并在去承载时衬底之后、去除位于第一电极21上的环形牺牲凸起之前，刻蚀第二电极23，形成贯穿第二电极23的环形沟槽，参照图16。在第二电极23上形成环形牺牲凸起，覆盖第一牺牲材料并覆盖部分第二电极23，在第二电极23上形成覆盖环形牺牲凸起的电极引出结构3，参照图17。去除第一牺牲材料及环形牺牲凸起。上述步骤对应的具体形成过程以及该薄膜体声波谐振器的其余步骤参照实施例1，此处不再赘述。
参照图18-19，在另一实施例中，在承载衬底4上依次形成第二电极23、形成压电层22、形成第一电极21；在第一电极21上形成电极引出结构，参照图18。在第一电极21上形成支撑层12；刻蚀支撑层12形成贯穿支撑层12的第一空腔121；提供第一衬底11，遮盖第一空腔121；去除承载衬底4，并翻转上述结构。在第二电极23上刻蚀形成贯穿第二电极23、压电层22和第一电极21的沟槽；在沟槽内填充牺牲材料，并覆盖部分沟槽周边区域的第二电极23；在填充导电材料，覆盖第二电极23表面的牺牲材料和部分第二电极23，形成电极引出结构，参照图19。去除牺牲材料。上述步骤的具体形成过程参照实施例1，此处不再赘述。
实施例 4
实施例4提供了一种薄膜体声波谐振器的制造方法，图20为根据本实施例薄膜体声波谐振器的制造方法制造的薄膜体声波谐振器的结构示意图，本实施例与实施例3的区别在于，实施例3中的压电层22形成有第一沟槽25，本实施例中的压电层22不刻蚀形成第一沟槽25，为完整的膜层，省去上述实施例3中对压电层22的刻蚀这一步骤，其余步骤参照上述实施例3。压电层22为完整膜层的有益效果可参照上述实施例2，此处不再赘述。
在上述实施例3和实施例4中，第一电极21和第二电极23均设有电极引出结构3，设置于第一电极21上电极引出结构和设置于第二电极23上的电极引出结构在环形空隙外围至少部分相互错开，以避免由于电位浮空产生的高频耦合问题，防止形成寄生电容，进而提高谐振器品质因数。当设置于第一电极21上电极引出结构和设置于第二电极23上的电极引出结构在环形空隙外围完全错开时，可以较好的避免高频耦合问题。电极引出结构3的结构及其与相应电极之间、支撑层之间的相对关系可参照实施例1，此处不再赘述。
实施例 5
本发明实施例5提供了一种滤波器，包括至少一个如上述方法制造出的薄膜体声波谐振器。通过上述薄膜体声波谐振器连接形成滤波器，以确保该滤波器具有较好的结构稳定性，且由于谐振器的电极阻抗较低，可以提高滤波器的导电率，提高滤波的准确性。
需要说明的是，本说明书中的各个实施例均采用相关的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于结构实施例而言，由于其基本相似于方法实施例，所以描述的比较简单，相关之处参见方法实施例的部分说明即可。
上述描述仅是对本发明较佳实施例的描述，并非对本发明范围的任何限定，本发明领域的普通技术人员根据上述揭示内容做的任何变更、修饰，均属于权利要求书的保护范围。

Claims (22)

  1. 一种薄膜体声波谐振器的制造方法，其特征在于，包括：形成第一电极、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；在所述第一电极、所述第二电极至少其中之一上形成贯穿相应电极的环形沟槽；在具有所述环形沟槽的电极上形成具有拱形桥的电极引出结构，包括：形成环形牺牲凸起；形成覆盖所述环形牺牲凸起、边缘搭接在有效谐振区电极边缘上的电极引出结构；在所述第一电极上形成支撑层；图形化所述支撑层，形成贯穿所述支撑层的第一空腔，所述电极引出结构的拱形桥位于所述第一空腔范围内；提供第一衬底，所述第一衬底遮盖所述第一空腔；去除所述环形牺牲凸起形成环形空隙，所述环形空隙和所述环形沟槽相对。
  2. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述形成第一电极、压电层和第二电极的方法包括：提供承载衬底；在所述承载衬底上依次形成所述第二电极、形成压电层和形成第一电极；在所述第一衬底遮盖所述支撑层上的第一空腔后，去除所述承载衬底；所述第一电极、所述第二电极至少其中之一形成所述电极引出结构；在所述第一电极上形成电极引出结构包括：在形成所述第一电极后、形成所述支撑层之前，在所述第一电极上形成电极引出结构；在所述第二电极上形成电极引出结构包括：去除所述承载衬底后，在所述第二电极上形成所述电极引出结构；或，提供承载衬底；在所述承载衬底上形成所述第一电极；去除所述承载衬底后，依次在所述第一电极上形成压电层、形成第二电极；所述第一电极、所述第二电极至少其中之一形成所述电极引出结构；在所述第一电极上形成电极引出结构包括：在形成所述第一电极后、形成所述支撑层之前，在所述第一电极上形成电极引出结构；在所述第二电极上形成电极引出结构包括：去除所述承载衬底后，在所述第二电极上形成所述电极引出结构；；或，
    提供承载衬底；在所述承载衬底上依次形成压电层、形成第一电极；去除所述承载衬底后，在所述压电层上形成所述第二电极；所述第一电极、所述第二电极至少其中之一形成所述电极引出结构；在所述第一电极上形成电极引出结构包括：在形成所述第一电极后、形成所述支撑层之前，在所述第一电极上形成电极引出结构；在所述第二电极上形成电极引出结构包括：去除所述承载衬底后，在所述第二电极上形成所述电极引出结构。
  3. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，在形成相应电极之后，刻蚀相应电极形成贯穿相应电极的环形沟槽；
    在相应电极上形成所述环形沟槽之前或之后，在相应电极上形成电极引出结构。
  4. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述在相应电极上形成覆盖所述环形牺牲凸起、边缘搭接在有效谐振区电极边缘上的电极引出结构的方法包括：在相应电极上沉积导电材料，形成电极引出结构，所述电极引出结构覆盖设置于相应电极上的所述环形牺牲凸起；或，在相应电极上沉积导电材料，所述导电材料覆盖相应电极和形成于相应电极上的所述环形牺牲凸起；刻蚀所述导电材料，去除位于所述环形牺牲凸起围成的区域内的部分导电材料，以形成电极引出结构。
  5. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述电极引出结构从所述环形空隙的四周延伸至所述第一空腔外围的所述支撑层上。
  6. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述第一电极和/或所述第二电极的四周延伸至所述第一空腔外围的所述支撑层上。
  7. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述第一电极、所述第二电极其中之一设有电极引出结构，所述电极引出结构和未设有所述电极引出结构的相应电极分别具有延伸至所述有效谐振区外的第一部分，所述第一部分作为电极连接端。
  8. 根据权利要求7所述的薄膜体声波谐振器的制造方法，其特征在于，在形成所述电极引出结构时还包括图形化所述电极引出结构，在形成未设有所述电极引出结构的相应电极时还包括图形化所述相应电极，以使所述电极引出结构与未形成所述电极引出结构的相应电极至少部分在所述环形空隙的外围相互错开。
  9. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述第一电极和所述第二电极均形成电极引出结构，设置于所述第一电极上的电极引出结构和设置于所述第二电极上的电极引出结构分别具有延伸至所述有效谐振区外的第二部分，所述第二部分作为电极连接端。
  10. 根据权利要求9所述的薄膜体声波谐振器的制造方法，其特征在于，在形成所述电极引出结构时，还包括图形化所述电极引出结构，使形成于所述第一电极上的电极引出结构和形成于所述第二电极上的电极引出结构至少部分在所述环形空隙的外围相互错开；形成于所述第一电极上的电极引出结构的拱形桥结构与形成于所述第二电极上的电极引出结构的拱形桥结构相对设置。
  11. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述电极引出结构的阻抗低于相应电极的阻抗。
  12. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，电极引出结构的材料为金属材料，所述金属材料包括金、银、钨、铂、铝、铜、钛、锡、镍中的一种或多种。
  13. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述环形空隙为封闭的环形空隙。
  14. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，形成的压电层遮盖所述第一空腔并延伸至所述第一空腔外围；或，
    形成所述压电层后，刻蚀所述压电层，形成贯穿所述压电层的第一沟槽，所述第一沟槽与所述环形沟槽相对。
  15. 根据权利要求14所述的薄膜体声波谐振器的制造方法，其特征在于，所述第一沟槽为封闭的环形，所述环形空隙内围的压电层和所述环形空隙外围的压电层相互隔离；或者，所述第一沟槽为间断的环形，所述环形空隙内围的压电层通过间断处与所述环形空隙外围的所述压电层相互隔离。
  16. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述支撑层的材料包括：二氧化硅、氮化硅、氧化铝或氮化铝、氮氧化硅、碳氮化硅。
  17. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述在所述支撑层上形成第一衬底包括：在所述支撑层或所述第一衬底上形成键合层，通过所述键合层键合所述第一衬底和所述支撑层，以遮盖所述第一空腔。
  18. 根据权利要求17所述的薄膜体声波谐振器的制造方法，其特征在于，所述键合层的材料包括：氧化硅、氮化硅、氮氧化硅、碳氮化硅或硅酸乙酯。
  19. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述环形牺牲凸起的材料包括磷硅玻璃、低温二氧化硅、硼磷硅玻璃、锗、非晶碳、聚酰亚胺或光阻剂。
  20. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述第一电极或所述第二电极的材料包括：钼、铝、铜、钨、钽、铂、钌、铑、铱、铬、钛、金、锇、铼或钯中的一种或多种的组合。
  21. 根据权利要求1所述的薄膜体声波谐振器的制造方法，其特征在于，所述压电层的材料包括：氮化铝、氧化锌、锆钛酸铅、铌酸锂、石英、铌酸钾或钽酸锂。
  22. 一种滤波器，其特征在于，包括至少一个如权利要求1-21中任一所述的薄膜体声波谐振器的制造方法形成的薄膜体声波谐振器。
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