WO2022057768A1 - 一种薄膜体声波谐振器的制造方法 - Google Patents

一种薄膜体声波谐振器的制造方法 Download PDF

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Publication number
WO2022057768A1
WO2022057768A1 PCT/CN2021/117997 CN2021117997W WO2022057768A1 WO 2022057768 A1 WO2022057768 A1 WO 2022057768A1 CN 2021117997 W CN2021117997 W CN 2021117997W WO 2022057768 A1 WO2022057768 A1 WO 2022057768A1
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Prior art keywords
electrode
forming
piezoelectric layer
substrate
manufacturing
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PCT/CN2021/117997
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English (en)
French (fr)
Inventor
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 WO2022057768A1 publication Critical patent/WO2022057768A1/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
    • H03H9/15—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
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] 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
    • H03H2003/023—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

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.
  • the terminal equipment needs to be able to transmit data using different carrier frequency spectrums.
  • RF systems also impose stringent performance requirements.
  • the radio frequency filter is an important part of the radio frequency system, which can filter out the interference and noise outside the communication spectrum to meet the requirements of the radio frequency system and the communication protocol for the signal-to-noise ratio. Taking a mobile phone as an example, since each frequency band needs a corresponding filter, dozens of filters may need to be set in a mobile phone.
  • 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 cavity-type thin-film bulk acoustic wave resonators currently produced have problems such as shear wave loss, insufficient structural strength, so that the quality factor (Q) cannot be further improved, and the yield is low, so they cannot meet the needs of high-performance RF systems.
  • the purpose of the present invention is to provide a method for manufacturing a thin film bulk acoustic wave resonator, which can improve the quality factor of the thin film bulk acoustic wave resonator, thereby improving the device performance.
  • the present invention provides a method for manufacturing a thin film bulk acoustic resonator, comprising: forming a first electrode, a second electrode and a piezoelectric layer, wherein the piezoelectric layer is located on the first electrode and the first electrode and the second electrode.
  • the method for forming the electrode with the arched bridge includes: forming annular sacrificial protrusions; depositing conductive a material layer covering the annular sacrificial protrusion and the peripheral area of the annular sacrificial protrusion; removing the annular sacrificial protrusion to form an annular space.
  • the beneficial effect of the present invention is that: the first electrode and/or the second electrode form an arched bridge structure, the arched bridge forms a closed ring, and the arched bridge and the surface of the plane where the piezoelectric layer is located form an annular gap, so that the effective resonance area is
  • the ends of the first electrode and/or the second electrode at the boundary are in contact with the gas in the void, so as to achieve the effect of eliminating boundary clutter of the electrodes in the effective resonance region, thereby improving the Q value of the resonator.
  • the arched bridge structure of the electrode serves as the boundary of the effective resonant area and surrounds the entire effective resonant area.
  • the electrode can extend from the periphery of the effective resonant area to the first substrate, thereby improving the mechanical strength of the resonator.
  • the piezoelectric layer above the cavity is not etched to form structures such as grooves and holes (compared to the case where grooves are provided in the piezoelectric layer), which can ensure the structural strength of the resonator and improve the finished product of the resonator. Rate.
  • the projections of the first electrode and the second electrode in the outer peripheral area of the arch bridge on the plane where the piezoelectric layer is located are staggered, which can avoid the problem of high-frequency coupling caused by the existence of potential floating, prevent the formation of parasitic capacitance, and help improve resonance. device quality factor.
  • a groove is provided in the piezoelectric layer, so that the edge of the piezoelectric layer is exposed to the gas, which can suppress the shear wave loss of the piezoelectric layer and improve the Q value of the resonator.
  • a first cavity is formed by etching the support layer, a first substrate is bonded on the support layer to cover the first cavity, an annular sacrificial protrusion is formed on the first electrode or the second electrode, and the annular sacrificial protrusion is removed.
  • FIGS. 1 to 7 are schematic structural diagrams corresponding to different steps of the manufacturing method of the thin-film bulk acoustic resonator according to Embodiment 1 of the present invention.
  • FIGS. 8 to 13 are schematic structural diagrams corresponding to different steps of the manufacturing method of the thin-film bulk acoustic resonator according to Embodiment 2 of the present invention.
  • FIG. 14 to FIG. 20 are schematic structural diagrams corresponding to different steps of the manufacturing method of the thin-film bulk acoustic resonator according to Embodiment 3 of the present invention.
  • FIG. 21 to FIG. 26 are schematic structural diagrams corresponding to different steps of the manufacturing method of the thin-film bulk acoustic resonator according to Embodiment 4 of the present invention.
  • Embodiment 1 of the present invention provides a method for manufacturing a thin film bulk acoustic resonator, including: S01: forming a first electrode, a second electrode and a piezoelectric layer, wherein the piezoelectric layer is located between the first electrode and the piezoelectric layer Between the second electrodes; S02: forming a support layer on the first electrode; S03: patterning the support layer to form a first cavity penetrating the support layer; S04: forming a first cavity on the support layer A substrate, the first substrate covers the first cavity; S05: At least one of the first electrode and the second electrode has an arched bridge, and the method for forming the electrode with the arched bridge includes: : forming a ring-shaped sacrificial protrusion; depositing a conductive material layer to cover the ring-shaped sacrificial protrusion and the surrounding area of the ring-shaped sacrificial protrusion; removing the ring-shaped sacrificial protrusion to
  • step S0N does not represent a sequence.
  • FIG. 1 to FIG. 7 are schematic structural diagrams corresponding to each step of the manufacturing method of the thin-film bulk acoustic resonator of the present embodiment.
  • the method for forming the first electrode 101 , the second electrode 103 and the piezoelectric layer 102 includes: providing a carrier substrate 1000 and forming the second electrode 103 on the carrier substrate 1000 A piezoelectric layer 102 is formed on the second electrode 103 ; a first electrode 101 is formed on the piezoelectric layer 102 , wherein the first electrode 101 is formed with an arch bridge structure 30 .
  • a carrier substrate 1000 is provided, and the carrier substrate may be a semiconductor material such as 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 second electrode 103 can be formed on the carrier substrate by a physical vapor deposition process, and the material of the second electrode 103 can be any suitable conductive material or semiconductor material known in the art, wherein the conductive material can be a conductive material.
  • Metal materials 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 formed of the above metals, the said The semiconductor material is, for example, Si, Ge, SiGe, SiC, SiGeC, or the like.
  • the piezoelectric layer 102 can be deposited and formed to cover the second electrode 103 using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition.
  • the piezoelectric layer 102 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 102 may further include a rare earth metal, such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). .
  • the piezoelectric layer 102 may further include transition metals such as zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). at least one.
  • a sacrificial layer material is deposited on the piezoelectric layer 102, and the sacrificial layer material includes: phosphosilicate glass, low temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist.
  • the patterned sacrificial layer material forms a ring-shaped sacrificial protrusion 31, and the sacrificial protrusion 31 is a continuous structure, enclosing a closed ring.
  • the boundary of the ring defines the boundary of the effective resonance area of the resonator.
  • the shape of the effective resonance region is an irregular polygon. In other embodiments, the effective resonance region may also be a circle or an ellipse, or an irregular pattern formed by arcs and straight lines.
  • a first electrode 101 is formed to cover the annular sacrificial protrusion 31 and the piezoelectric layer 102 , wherein the first electrode 101 above the annular sacrificial protrusion 31 forms an arch bridge 30 structure.
  • the material and formation method of the first electrode 101 refer to the material and formation method of the second electrode 103 .
  • the height of the annular sacrificial protrusion 31 is greater than the thickness of the first electrode 101 . In other embodiments, the height of the annular sacrificial protrusion 31 (the distance H1 between the two arrows in FIG.
  • the height of the annular sacrificial protrusion 31 may be equal to the thickness of the first electrode (between the two arrows in FIG. 3 )
  • the distance H2 is the thickness of the first electrode) or greater than the thickness of the first electrode, and the annular sacrificial protrusion 31 will be removed in the subsequent process to form an annular gap.
  • the minimum height of the annular sacrificial protrusion 31 should be such that the resonance of the resonator cannot be achieved here, so as to achieve the purpose of defining the boundary of the effective resonance region.
  • the height of the gap is greater than the thickness of the first electrode 101 , so that the end of the first electrode 101 at the boundary of the effective resonator can be completely exposed in the gap, so as to better prevent the leakage of transverse acoustic waves from the first electrode 101 , to improve the quality factor of the resonator.
  • the arched bridge 30 structure of the first electrode 101 surrounds the entire effective resonance region from the outer periphery of the effective resonance region, thereby improving the mechanical strength of the resonator.
  • a support layer 100b is formed to cover the first electrode 101, and the material of the support layer 100b includes a dielectric material such as silicon dioxide, silicon nitride, aluminum oxide, aluminum nitride, silicon oxynitride or silicon carbonitride.
  • the support layer 100b may be formed through a chemical vapor deposition process.
  • the support layer 100b is etched to form a first cavity 200, the bottom of the first cavity 200 exposes the first electrode 101, and the boundary of the first cavity 200 surrounds the boundary where the arch bridge 30 is located.
  • the cross-sectional shape of the first cavity 200 may be a circle, an ellipse or a polygon.
  • the etching process may be dry etching or wet etching. Dry etching processes include, but are not limited to, reactive ion etching, ion beam etching, plasma etching, or laser cutting.
  • the method of removing the annular sacrificial protrusion can be selected according to the material of the annular sacrificial protrusion.
  • the material of the annular sacrificial protrusion is polyimide or photoresist
  • the The method of ashing is to remove.
  • the method of ashing is to chemically react with the annular sacrificial convex material through the oxygen released in the hole at a temperature of 250 degrees Celsius, and the generated gaseous substances are volatilized.
  • the annular sacrificial convex material is low temperature dioxide
  • silicon is removed, it is removed by the reaction between hydrofluoric acid solvent and low temperature silica.
  • the release hole may be formed in an edge region of the first cavity.
  • a first substrate 100 a is formed on the support layer 100 b, and the first substrate 100 a covers the first cavity 200 .
  • the support layer 100b may be combined with the first substrate 100a by means of bonding, which may include covalent bonding, adhesive bonding or fusion bonding.
  • the method for forming the first substrate 100a on the supporting layer 100b is as follows: forming a bonding layer on the supporting layer 100b or the first substrate 100a, and bonding through the bonding layer the first substrate and the support layer to cover the first cavity.
  • the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.
  • the material of the first substrate 100a may be a semiconductor material, and for details, reference may be made to the material of the carrier substrate 1000 .
  • the carrier substrate is removed to expose the second electrode 103 .
  • the second electrode is patterned, so that the projections of the first electrode 101 and the second electrode 103 in the direction of the first substrate are staggered on the outer circumference of the arched bridge ( Figure 7 shows the case where the projections of the two are staggered in some areas), the staggered projections can avoid the high-frequency coupling problem caused by the existence of potential floating, prevent the formation of parasitic capacitance, and help improve the quality factor of the resonator.
  • both the first electrode and the second electrode may be patterned, so that the projections of the first electrode and the second electrode outside the effective resonance area are staggered from each other.
  • both the first electrode 101 and the second electrode 103 extend from the periphery of the effective resonant region to the first substrate 100 on the periphery of the first cavity 200, which ensures the structural strength of the resonator and improves the finished product. Rate.
  • the carrier substrate may be removed by a grinding process or a wet etching process, or a release layer may be formed on the carrier substrate before the second electrode 103 is formed, and the carrier substrate may be peeled off by removing the release layer.
  • the material of the release 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 upper and lower surfaces of the piezoelectric layer 102 are flat, so that the piezoelectric layer 102 has a better lattice orientation, which improves the piezoelectric properties of the piezoelectric layer 102 and further improves the overall performance of the resonator.
  • the area where the arched bridge 30 is located constitutes the boundary of the effective resonance area.
  • the boundary of the effective resonance area may be defined by other structures, and the arched bridge structure is arranged at the periphery of the effective resonance area.
  • FIG. 8 to FIG. 13 are schematic structural diagrams corresponding to each step of the manufacturing method of the thin-film bulk acoustic resonator of the present embodiment.
  • the difference between this embodiment and Embodiment 1 is that the grooves 40 are formed in the piezoelectric layer 102 .
  • a carrier substrate 1000 is provided, a second electrode 103 is formed on the carrier substrate 1000 ; a piezoelectric layer 102 is formed on the second electrode 103 .
  • the material of the carrier substrate 1000 the material and the formation method of the second electrode 103 and the piezoelectric layer 102 , refer to Embodiment 1, and details are not repeated here.
  • a trench 40 is formed in the piezoelectric layer 102, and the trench 40 may be formed by a dry etching process, including but not limited to reactive ion etching, ion beam etching, plasma Body etching or laser cutting.
  • the trench 40 is a closed ring and penetrates through the piezoelectric layer 102 , and the inner sidewall of the trench 40 coincides with the boundary of the effective resonance region of the resonator.
  • the trench 40 may also be an intermittent annular structure or a non-annular structure, for example, only a certain side boundary of the effective resonance region is provided.
  • the piezoelectric layer in the effective resonance area is connected with the piezoelectric layer outside the effective resonance area through the discontinuity.
  • the trenches 40 may also be disposed outside the effective resonance region.
  • a trench 40 is formed in the piezoelectric layer 102 so that the end face of the piezoelectric layer 102 and the gas in the trench 40 form a reflection interface, so as to effectively suppress the leakage of transverse waves in the piezoelectric layer 102 and improve the quality factor of the resonator.
  • the trench 40 may not penetrate through the piezoelectric layer 102 . It can be understood that when the trench 40 is a closed ring and penetrates through the piezoelectric layer 102 , and the sidewall of the trench 40 coincides with the boundary of the effective resonance region, the effect of suppressing the shear wave leakage is the best.
  • a sacrificial material layer is formed, covering the piezoelectric layer 102, the sacrificial material layer is filled into the trench, the material and the formation method of the sacrificial material layer refer to Embodiment 1, the sacrificial material layer is patterned, and a ring is formed above the trench Sacrifice bump 31 .
  • the structure of the annular sacrificial protrusion 31 refer to Embodiment 1 for height.
  • a first electrode 101 is formed to cover the annular sacrificial bump 31 and the piezoelectric layer 102 , wherein the first electrode 101 above the annular sacrificial bump 31 forms an arch bridge 30 structure.
  • the material and forming method of the first electrode 101 refer to Embodiment 1, and details are not repeated here.
  • a support layer 100b is formed to cover the first electrode 101, and the material of the support layer 100b includes a dielectric material such as silicon dioxide, silicon nitride, aluminum oxide, aluminum nitride, silicon oxynitride or silicon carbonitride.
  • the support layer 100b may be formed through a chemical vapor deposition process.
  • the support layer 100b is etched to form a first cavity 200, the bottom of the first cavity 200 exposes the first electrode 101, and the boundary of the first cavity 200 surrounds the boundary where the arch bridge 30 is located.
  • the annular sacrificial protrusion and the sacrificial material in the trench are removed.
  • the annular sacrificial protrusion is in contact with the sacrificial material in the groove, and the materials used for both are the same, which can be removed at one time.
  • the removal method refer to Embodiment 1.
  • the position of the annular sacrificial protrusion is An annular space is formed, and the annular space is communicated with the groove.
  • a first substrate 100 a is formed on the support layer 100 b, and the first substrate 100 a covers the first cavity 200 .
  • the shape and forming method of the first cavity and the method for forming the first substrate 100a on the support layer 100b are all referred to in Embodiment 1, and are not repeated here.
  • the carrier substrate is removed to expose the second electrode 103 .
  • the second electrode is patterned, so that the projections of the first electrode 101 and the second electrode 103 in the direction of the first substrate are staggered on the outer circumference of the arched bridge .
  • the benefits of this arrangement and other structural forms of the first electrode and the second electrode can be referred to in Embodiment 1, which will not be repeated here.
  • the annular space and the groove communicate with each other.
  • the annular space and the groove can be isolated from each other.
  • the boundary of the effective resonance area is defined by the sidewall of the groove, and the annular space is provided on the outer periphery of the groove. .
  • FIG. 14 to 20 are schematic structural diagrams corresponding to each step of the manufacturing method of the thin film bulk acoustic wave resonator of the present embodiment.
  • the order of forming the first electrode, the piezoelectric layer and the second electrode is different, and both the first electrode and the second electrode are formed with arch bridges.
  • a carrier substrate 1000 is provided on which the piezoelectric layer 102 is formed.
  • the trenches 40 are formed in the piezoelectric layer 102 .
  • the material of the carrier substrate 1000 , the material and the forming method of the piezoelectric layer 102 refer to Embodiment 1, and the structure and forming method of the trench 40 refer to Embodiment 2.
  • a sacrificial material layer is formed, covering the piezoelectric layer 102, and the sacrificial material layer is filled into the trench.
  • the material and formation method of the sacrificial material layer refer to Embodiment 1, pattern the sacrificial material layer, and form the first layer above the trench.
  • An annular sacrificial protrusion 31-1 Regarding the structure of the first annular sacrificial protrusion 31 - 1 , the height refers to the annular sacrificial protrusion of Embodiment 1.
  • a first electrode 101 is formed to cover the first annular sacrificial protrusion 31-1 and the piezoelectric layer 102, wherein the first electrode 101 above the first annular sacrificial protrusion 31-1 forms an arch bridge 30 structure.
  • the material and formation method of the first electrode 101 refer to Embodiment 1.
  • a support layer 100b is formed to cover the first electrode 101, and the material of the support layer 100b includes a dielectric material such as silicon dioxide, silicon nitride, aluminum oxide, aluminum nitride, silicon oxynitride or silicon carbonitride.
  • the support layer 100b may be formed through a chemical vapor deposition process.
  • the support layer 100b is etched to form a first cavity 200, the bottom of the first cavity 200 exposes the first electrode 101, and the boundary of the first cavity 200 surrounds the boundary where the arch bridge 30 is located.
  • the annular sacrificial protrusion and the sacrificial material in the trench are removed.
  • an annular space is formed at the position of the annular sacrificial protrusion, and the annular space communicates with the groove.
  • Example 2 for the removal method of the sacrificial material.
  • a first substrate 100 a is formed on the support layer 100 b, and the first substrate 100 a covers the first cavity 200 .
  • the shape and forming method of the first cavity and the method of forming the first substrate 100a on the support layer 100b are all referred to in Embodiment 1.
  • the carrier substrate is removed to expose the piezoelectric layer 102 , and the method of removing the carrier substrate refers to Embodiment 1.
  • the trench runs through the piezoelectric layer 102.
  • a sacrificial material layer is formed to cover the piezoelectric layer 102 and the sacrificial material in the trench.
  • a sacrificial material layer is formed, and a second annular sacrificial protrusion 31-2 is formed above the trench.
  • the structure and height of the second annular sacrificial protrusion 31-2 refer to the first annular sacrificial protrusion 31-1.
  • the second electrode 103 is formed to cover the second annular sacrificial protrusion 31-2 and the piezoelectric layer 102, wherein the second electrode 103 above the second annular sacrificial protrusion 31-2 forms the arch bridge 30 structure.
  • the material and formation method of the second electrode 103 refer to the material and formation method of the second electrode 103 .
  • the sacrificial material in the first annular sacrificial bump, the second annular sacrificial bump, and the trenches is removed. In this embodiment, the three are connected and can be removed at one time. Refer to Embodiment 2 for the removal method.
  • the arched bridge 30 of the first electrode 101 and the arched bridge 30 of the second electrode 103 are disposed opposite to each other, and the annular space and the groove formed by the two arched bridges communicate with each other.
  • 21 to 26 are schematic structural diagrams corresponding to each step of the manufacturing method of the thin film bulk acoustic wave resonator of the present embodiment.
  • FIG. 21 to FIG. 26 please refer to FIG. 21 to FIG. 26 to describe the manufacturing method of the thin film bulk acoustic resonator.
  • the order in which the first electrode, the piezoelectric layer and the second electrode are formed is different.
  • the material, structure and formation method of the film layer involved in this embodiment refer to the above three embodiments, and this embodiment only describes the manufacturing steps.
  • a carrier substrate 1000 is provided, a sacrificial material layer is formed on the carrier substrate 1000, and the sacrificial material layer is patterned to form a first annular sacrificial protrusion 31-1.
  • a first electrode 101 is formed to cover the first annular sacrificial bump 31 - 1 and the carrier substrate 1000 .
  • the first electrode 101 is formed with the arch bridge 30 .
  • a support layer 100 b is formed, and the support layer 100 b is etched to form a first cavity 200 .
  • the bottom of the first cavity 200 exposes the first electrode 101 , and the boundary of the first cavity 200 surrounds the boundary where the arch bridge 30 is located. .
  • a first substrate 100 a is formed on the support layer 100 b, and the first substrate 100 a covers the first cavity 200 .
  • the carrier substrate is removed, exposing the piezoelectric layer 102 .
  • a sacrificial material layer is formed to cover the piezoelectric layer 102, and the sacrificial material layer is patterned to form a first annular sacrificial protrusion 31-2.
  • the first annular sacrificial protrusion and the second annular sacrificial protrusion are disposed opposite to each other.
  • the second electrode 103 is formed to cover the second annular sacrificial protrusion 31-2 and the piezoelectric layer 102, wherein the second electrode 103 above the second annular sacrificial protrusion 31-2 forms the arch bridge 30 structure.
  • the first annular sacrificial protrusion and the second annular sacrificial protrusion are removed.
  • one or both of the first electrode and the second electrode can form an arched bridge, and a groove or no groove can also be formed in the piezoelectric layer. a situation.
  • the first electrode and/or the second electrode of the present invention form an arched bridge structure, the arched bridge forms a closed ring, and the arched bridge and the surface of the plane where the piezoelectric layer is located form an annular gap, so that the effective resonance area is
  • the ends of the first electrode and/or the second electrode at the boundary are in contact with the gas in the void, so as to achieve the effect of eliminating boundary clutter of the electrodes in the effective resonance region, thereby improving the Q value of the resonator.
  • the arched bridge structure of the electrode serves as the boundary of the effective resonant area and surrounds the entire effective resonant area, and the electrode can extend from the surrounding area of the effective resonant area to the first substrate, which not only improves the mechanical strength of the resonator, but also reduces the cost of the resonator. impedance of the electrodes.
  • the piezoelectric layer above the cavity is not etched to form structures such as grooves and holes (compared to the case where grooves are provided in the piezoelectric layer), which can ensure the structural strength of the resonator and improve the yield of the resonator. .
  • the projections of the first electrode and the second electrode in the outer peripheral area of the arch bridge on the plane where the piezoelectric layer is located are staggered, which can avoid the problem of high-frequency coupling caused by the existence of potential floating, prevent the formation of parasitic capacitance, and help improve resonance. device quality factor.
  • a groove is provided in the piezoelectric layer, so that the edge of the piezoelectric layer is exposed to the gas, which can suppress the shear wave loss of the piezoelectric layer and improve the Q value of the resonator.

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Abstract

本发明公开了一种薄膜体声波谐振器的制造方法，包括：形成第一电极、第二电极和压电层，其中压电层位于第一电极和第二电极之间；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；在支撑层上形成第一衬底，第一衬底遮盖第一空腔；第一电极、第二电极至少其中之一具有拱形桥，具有拱形桥的电极的形成方法包括：形成环形牺牲凸起；沉积导电材料层，覆盖环形牺牲凸起及环形牺牲凸起周边区域；去除环形牺牲凸起形成环形空隙。本发明用电极的拱形桥结构从有效谐振区的外周包围整个有效谐振区，提高了谐振器的机械强度。

Description

一种薄膜体声波谐振器的制造方法 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。
 背景技术
随着无线通讯技术的不断发展，为了满足各种无线通讯终端的多功能化需求，终端设备需要能够利用不同的载波频谱传输数据，同时，为了在有限的带宽内支持足够的数据传输率，对于射频系统也提出了严格的性能要求。射频滤波器是射频系统的重要组成部分，可以将通信频谱外的干扰和噪声滤出以满足射频系统和通信协议对于信噪比的需求。以手机为例，由于每一个频带需要有对应的滤波器，一台手机中可能需要设置数十个滤波器。
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，存在横波损失，结构强度不够，使品质因子（Q）无法进一步提高、成品率低等问题，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，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，本发明提供一种薄膜体声波谐振器的制造方法，包括：形成第一电极、第二电极和压电层，其中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；在所述支撑层上形成第一衬底，所述第一衬底遮盖所述第一空腔；所述第一电极、所述第二电极至少其中之一具有拱形桥，具有拱形桥的电极的形成方法包括：形成环形牺牲凸起；沉积导电材料层，覆盖所述环形牺牲凸起及所述环形牺牲凸起周边区域；去除所述环形牺牲凸起形成环形空隙。
 有益效果
本发明的有益效果在于：第一电极和/或第二电极形成拱形桥结构，拱形桥围成封闭的环形，拱形桥与压电层所在平面的表面形成环形空隙，使有效谐振区边界处的第一电极和/或第二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。
进一步地，电极的拱形桥结构作为有效谐振区的边界，包围整个有效谐振区，电极可以从有效谐振区的四周延伸至第一衬底上，提高了谐振器的机械强度。
进一步地，空腔上方的压电层没有经过刻蚀形成沟槽、孔洞类的结构（相对于压电层中设有沟槽的情况），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，拱形桥外周区域的第一电极和第二电极在压电层所在平面的投影相互错开，可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。
进一步地，压电层中设有沟槽，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，提升谐振器的Q值。
进一步地，通过刻蚀支撑层形成第一空腔，在支撑层上键合第一衬底遮盖第一空腔，在形成第一电极或第二电极之形成环形牺牲凸起，去除环形牺牲凸起形成拱形桥结构，与半导体工艺相容，工艺流程简单。
 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至图7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8至图13示出了本发明实施例2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14至图20示出了本发明实施例3的薄膜体声波谐振器的制造方法在不同步骤对应的结构示意图。
图21至图26示出了本发明实施例4的薄膜体声波谐振器的制造方法在不同步骤对应的结构示意图。
附图标记说明： 100a-第一衬底；100b-支撑层；101-第一电极；102-压电层；103-第二电极；200-第一空腔；201-牺牲层；30-拱形桥；31-环形牺牲凸起；31-1-第一环形牺牲凸起；31-2-第二环形牺牲凸起；40-沟槽；1000-承载衬底。
 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
本发明实施例1提供了一种薄膜体声波谐振器的制造方法，包括：S01：形成第一电极、第二电极和压电层，其中所述压电层位于所述第一电极和所述第二电极之间；S02：在所述第一电极上形成支撑层；S03：图形化所述支撑层，形成贯穿所述支撑层的第一空腔；S04：在所述支撑层上形成第一衬底，所述第一衬底遮盖所述第一空腔；S05：所述第一电极、所述第二电极至少其中之一具有拱形桥，具有拱形桥的电极的形成方法包括：形成环形牺牲凸起；沉积导电材料层，覆盖所述环形牺牲凸起及所述环形牺牲凸起周边区域；去除所述环形牺牲凸起形成环形空隙。
需要说明的是，步骤S0N不代表先后顺序。
图1至图7是本实施例薄膜体声波谐振器的制造方法各步骤对应的结构示意图。下面请参考图1至图7对薄膜体声波谐振器的制造方法进行阐述。
参考图1至图3，本实施例中，形成第一电极101、第二电极103和压电层102的方法包括：提供承载衬底1000，在所述承载衬底1000上形成第二电极103；在所述第二电极103上形成压电层102；在所述压电层102上形成第一电极101，其中，第一电极101形成有拱形桥结构30。
具体地，参考图1，提供承载衬底1000，承载衬底可以半导体材料，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。可以通过物理气相沉积工艺在承载衬底上形成第二电极103，第二电极103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。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压电层102，覆盖第二电极103。压电层102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102材料为氮化铝(AlN)时，压电层102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102的材料为氮化铝(AlN)时，压电层102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。
参考图2，在压电层102上沉积形成牺牲层材料，牺牲层材料包括：磷硅玻璃、低温二氧化硅、硼磷硅玻璃、锗、碳、聚酰亚胺或光阻剂。图形化牺牲层材料形成环形牺牲凸起31，牺牲凸起31为连续的结构，围成封闭的环形，本实施例中，环形的边界界定了谐振器有效谐振区的边界，本实施例中，有效谐振区的形状为不规则多边形。在其他实施例中，有效谐振区也可以是圆形或者椭圆形或者由弧线和直线构成的不规则图形。
参考图3，形成第一电极101，覆盖环形牺牲凸起31以及压电层102，其中环形牺牲凸起31上方的第一电极101形成了拱形桥30结构。第一电极101的材料和形成方法参照第二电极103的材料和形成方法。本实施例中，环形牺牲凸起31的高度大于第一电极101的厚度。在其他实施例中，环形牺牲凸起31的高度（图3中两个箭头之间的距离H1为环形牺牲凸起31的高度）可以等于第一电极的厚度（图3中两个箭头之间的距离H2为第一电极的厚度）或者大于第一电极的厚度，在后续工艺中将去除环形牺牲凸起31，形成环形空隙。环形牺牲凸起31的最小高度应满足在此处不能实现谐振器的谐振，以实现界定有效谐振区边界的目的。本实施例中，空隙高度大于第一电极101的厚度，这样可以使有效谐振器边界处的第一电极101的端部完全暴露在空隙中，更好的防止横向声波从第一电极101中泄露，提高谐振器的品质因数。另外，第一电极101的拱形桥30结构从有效谐振区的外周包围整个有效谐振区，提高了谐振器的机械强度。
参考图4，形成支撑层100b覆盖第一电极101，支撑层100b的材料包括介电材料，如二氧化硅、氮化硅、氧化铝、氮化铝、氮氧化硅或碳氮化硅。可以通过化学气相沉积工艺形成支撑层100b。
参考图5，刻蚀支撑层100b形成第一空腔200，第一空腔200的底部暴露出第一电极101，第一空腔200的边界包围拱形桥30所在的边界。第一空腔200的截面形状可以是圆形、椭圆形或者多边形。刻蚀工艺可以采用干法刻蚀也可以采用湿法腐蚀。干法刻蚀工艺包括但不限于反应离子刻蚀、离子束刻蚀、等离子体刻蚀或者激光切割。形成第一空腔200后，去除环形牺牲凸起，去除环形牺牲凸起的方式可以根据环形牺牲凸起的材料选择，当环形牺牲凸起的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，通过释放孔的氧与环形牺牲凸起材料发生化学反应，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。释放孔可以形成在第一空腔的边缘区域。
参考图6，在支撑层100b上形成第一衬底100a，所述第一衬底100a遮盖所述第一空腔200。支撑层100b可以通过键合的方式与第一衬底100a结合，键合的方式包括：共价键键合、粘结键合或熔融键合。本实施例中，在所述支撑层100b上形成第一衬底100a的方法为：在所述支撑层100b或所述第一衬底100a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。其中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。第一衬底100a的材料可以为半导体材料，具体可参照承载衬底1000的材料。
参考图7，去除承载衬底，暴露出第二电极103。本实施例中，还包括对第二电极进行图形化，使所述第一电极101和所述第二电极103在所述第一衬底方向上的投影在所述拱形桥的外周相互错开（图7中为两者的投影在部分区域相互错开的情况），投影相互错开可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。在另一个实施例中，也可以对第一电极和第二电极都进行图形化，使有效谐振区外的第一电极和第二电极的投影相互错开。在另一个实施例中，第一电极101和第二电极103均从有效谐振区的四周延伸至第一空腔200外围的第一衬底100上，保证了谐振器的结构强度，提高了成品率。
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103之前在承载衬底上形成释放层，通过去除释放层的方式剥离承载衬底。释放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。
本实施例中，压电层102的上表面和下表面均为平面，使压电层102具有较好的晶格取向，提高压电层102的压电特性，进而提高谐振器的整体性能。
本实施例中，拱形桥30所在的区域构成有效谐振区的边界，在其它实施例中有效谐振区的边界可以通过其它结构限定，拱形桥结构设置于有效谐振区的外围。技术效果是在写在结构之后的。
实施例 2
图8至图13是本实施例薄膜体声波谐振器的制造方法各步骤对应的结构示意图。下面请参考图8至图13对薄膜体声波谐振器的制造方法进行阐述。本实施例与实施例1的区别在于，压电层102中形成有沟槽40。
参照图8，提供承载衬底1000，在所述承载衬底1000上形成第二电极103；在所述第二电极103上形成压电层102。关于承载衬底1000的材料，第二电极103和压电层102的材料和形成方法参照实施例1，此处不再赘述。形成压电层102后，在压电层102中形成沟槽40，可以通过干法刻蚀工艺形成沟槽40，干法刻蚀工艺包括但不限于反应离子刻蚀、离子束刻蚀、等离子体刻蚀或者激光切割。本实施例中，沟槽40为封闭的环形，并贯穿压电层102，沟槽40的内侧壁与谐振器的有效谐振区的边界重合。在其它实施例中，沟槽40也可以是间断的环形结构或者非环形结构，如只设置有效谐振区的某侧边界处。此时有效谐振区内的压电层通过间断处与有效谐振区外的压电层相连接。在其它实施例中，沟槽40也可以设置在有效谐振区的外侧。在压电层102中形成沟槽40，使压电层102的端面与沟槽40中的气体形成反射界面，以有效抑制压电层102中的横波泄露，提高谐振器的品质因数。沟槽40也可以不贯穿压电层102。可以理解，当沟槽40为封闭的环形，并且贯穿压电层102，沟槽40侧壁与有效谐振区的边界重合时，抑制横波泄露的效果最好。
参考图9，形成牺牲材料层，覆盖压电层102，牺牲材料层填充进沟槽中，牺牲材料层的材料和形成方法参照实施例1，图形化牺牲材料层，在沟槽的上方形成环形牺牲凸起31。关于环形牺牲凸起31的结构，高度参照实施例1。
参考图10，形成第一电极101，覆盖环形牺牲凸起31以及压电层102，其中环形牺牲凸起31上方的第一电极101形成了拱形桥30结构。第一电极101的材料和形成方法参照实施例1，此处不再赘述。
参考图11，形成支撑层100b覆盖第一电极101，支撑层100b的材料包括介电材料，如二氧化硅、氮化硅、氧化铝、氮化铝、氮氧化硅或碳氮化硅。可以通过化学气相沉积工艺形成支撑层100b。
参考图12，刻蚀支撑层100b形成第一空腔200，第一空腔200的底部暴露出第一电极101，第一空腔200的边界包围拱形桥30所在的边界。形成第一空腔200后，去除环形牺牲凸起以及位于沟槽中的牺牲材料。本实施例中，环形牺牲凸起和沟槽中的牺牲材料相接触，两者采用的材料相同，可以一次性去除，去除的方法参照实施例1，牺牲材料去除后，环形牺牲凸起的位置形成环形空隙，环形空隙和沟槽相连通。在支撑层100b上形成第一衬底100a，所述第一衬底100a遮盖所述第一空腔200。第一空腔的形状和形成方法以及在支撑层100b上形成第一衬底100a的方法均参照实施例1，此处不在赘述。
参考图13，去除承载衬底，暴露出第二电极103。去除承载衬底的方法参照实施例1。本实施例中，还包括对第二电极进行图形化，使所述第一电极101和所述第二电极103在所述第一衬底方向上的投影在所述拱形桥的外周相互错开。这种设置方式的好处及第一电极和第二电极其它的结构形式参照实施例1，此处不再赘述。本实施例中，环形空隙和沟槽相互连通，在其它实施例中，环形空隙和沟槽可以相互隔离，如由沟槽的侧壁定义有效谐振区的边界，环形空隙设置于沟槽的外周。
实施例 3
图14至图20是本实施例薄膜体声波谐振器的制造方法各步骤对应的结构示意图。下面请参考图14至图20对薄膜体声波谐振器的制造方法进行阐述。本实施例中，第一电极、压电层和第二电极形成的顺序不同，并且第一电极和第二电极均形成有拱形桥。
参考图14，提供承载衬底1000，在所述承载衬底1000上形成压电层102。在压电层102中形成沟槽40。承载衬底1000的材料，压电层102的材料和形成方法参照实施例1，沟槽40的结构和形成方法参照实施例2。
参考图15，形成牺牲材料层，覆盖压电层102，牺牲材料层填充进沟槽中，牺牲材料层的材料和形成方法参照实施例1，图形化牺牲材料层，在沟槽的上方形成第一环形牺牲凸起31-1。关于第一环形牺牲凸起31-1的结构，高度参照实施例1的环形牺牲凸起。
参考图16，形成第一电极101，覆盖第一环形牺牲凸起31-1以及压电层102，其中第一环形牺牲凸起31-1上方的第一电极101形成了拱形桥30结构。第一电极101的材料和形成方法参照实施例1。
参考图17，形成支撑层100b覆盖第一电极101，支撑层100b的材料包括介电材料，如二氧化硅、氮化硅、氧化铝、氮化铝、氮氧化硅或碳氮化硅。可以通过化学气相沉积工艺形成支撑层100b。
参考图18，刻蚀支撑层100b形成第一空腔200，第一空腔200的底部暴露出第一电极101，第一空腔200的边界包围拱形桥30所在的边界。形成第一空腔200后，去除环形牺牲凸起以及位于沟槽中的牺牲材料。牺牲材料去除后，环形牺牲凸起的位置形成环形空隙，环形空隙和沟槽相连通。牺牲材料的去除方法参照实施例2。在支撑层100b上形成第一衬底100a，所述第一衬底100a遮盖所述第一空腔200。第一空腔的形状和形成方法以及在支撑层100b上形成第一衬底100a的方法均参照实施例1。
参考图19，去除承载衬底，暴露出压电层102，去除承载衬底的方法参照实施例1。本实施例中，沟槽贯穿压电层102，去除承载衬底后，形成牺牲材料层，覆盖压电层102和沟槽中牺牲材料，牺牲材料层的材料和形成方法参照实施例1，图形化牺牲材料层，在沟槽的上方形成第二环形牺牲凸起31-2。关于第二环形牺牲凸起31-2的结构、高度参照第一环形牺牲凸起31-1。
参考图20，形成第二电极103，覆盖第二环形牺牲凸起31-2以及压电层102，其中第二环形牺牲凸起31-2上方的第二电极103形成了拱形桥30结构。第二电极103的材料和形成方法参照第二电极103的材料和形成方法。去除第一环形牺牲凸起、第二环形牺牲凸起以及沟槽中的牺牲材料。本实施例中，三者相连接，可以一次性去除，去除的方法可参照实施例2。本实施例的第一电极101的拱形桥30和第二电极103的拱形桥30相对设置，两个拱形桥形成的环形空隙和沟槽三者相互连通。
实施例 4
图21至图26是本实施例薄膜体声波谐振器的制造方法各步骤对应的结构示意图。下面请参考图21至图26对薄膜体声波谐振器的制造方法进行阐述。本实施例中，第一电极、压电层和第二电极形成的顺序不同。本实施例中涉及的膜层的材料、结构和形成方法参照以上3个实施例，本实施例只是描述制造的步骤。
参考图21，提供承载衬底1000，在承载衬底1000上形成牺牲材料层，图形化牺牲材料层，形成第一环形牺牲凸起31-1。
参考图22，形成第一电极101，覆盖第一环形牺牲凸起31-1和承载衬底1000。形成的第一电极101带有拱形桥30。
参考图23，形成支撑层100b，刻蚀支撑层100b形成第一空腔200，第一空腔200的底部暴露出第一电极101，第一空腔200的边界包围拱形桥30所在的边界。
参考图24，在支撑层100b上形成第一衬底100a，所述第一衬底100a遮盖所述第一空腔200。
参考图25，去除承载衬底，暴露出压电层102。形成牺牲材料层，覆盖压电层102，图形化牺牲材料层，形成第一环形凸起31-2，本实施例中，第一环形牺牲凸起和第二环形牺牲凸起相对设置。
参考图26，形成第二电极103，覆盖第二环形牺牲凸起31-2以及压电层102，其中第二环形牺牲凸起31-2上方的第二电极103形成了拱形桥30结构。去除第一环形牺牲凸起、第二环形牺牲凸起。
以上实施例的方法中，第一电极和第二电极其中之一或两者均可以形成拱形桥，压电层中也均可以形成沟槽或不形成沟槽，以上实施例只是举例说明几种情况。
综上所述，本发明第一电极和/或第二电极形成拱形桥结构，拱形桥围成封闭的环形，拱形桥与压电层所在平面的表面形成环形空隙，使有效谐振区边界处的第一电极和/或第二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。
进一步地，电极的拱形桥结构作为有效谐振区的边界，包围整个有效谐振区，电极可以从有效谐振区的四周延伸至第一衬底上，不仅提高了谐振器的机械强度，也降低了电极的阻抗。
进一步地，空腔上方的压电层没有经过刻蚀形成沟槽、孔洞类的结构（相对于压电层中设置沟槽的情况），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，拱形桥外周区域的第一电极和第二电极在压电层所在平面的投影相互错开，可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。
进一步地，压电层中设有沟槽，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，提升谐振器的Q值。
进一步地，通过刻蚀支撑层形成第一空腔，在支撑层上键合第一衬底遮盖第一空腔，在形成第一电极或第二电极之形成环形牺牲凸起，去除环形牺牲凸起形成拱形桥结构，与半导体工艺相容，工艺流程简单。
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。
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 (14)

  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、第二电极和压电层，其中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；在所述支撑层上形成第一衬底，所述第一衬底遮盖所述第一空腔；所述第一电极、所述第二电极至少其中之一具有拱形桥，具有拱形桥的电极的形成方法包括：形成环形牺牲凸起；沉积导电材料层，覆盖所述环形牺牲凸起及所述环形牺牲凸起周边区域；去除所述环形牺牲凸起形成环形空隙。
  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、第二电极和压电层的方法包括：提供承载衬底；在所述承载衬底上形成第一电极；形成所述第一衬底后，去除所述承载衬底，在所述第一电极与所述第一空腔相对的一侧形成压电层；在所述压电层上形成第二电极；或，提供承载衬底；在所述承载衬底上形成压电层；在所述压电层上形成第一电极；形成所述第一衬底后，去除所述承载衬底，在所述压电层上形成第二电极；或提供承载衬底；在所述承载衬底上形成第二电极；在所述第二电极上形成压电层；在所述压电层上形成第一电极；形成所述第一衬底后，去除所述承载衬底。
  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，形成所述压电层包括：形成的所述压电层遮盖所述第一空腔且延伸至所述第一空腔外；或，形成所述压电层后，在所述压电层中形成沟槽，所述沟槽与所述拱形桥相对。
  4. 根据权利要求4所述的薄膜体声波谐振器的制造方法，其特征在于，所述沟槽为封闭的环形，或，所述沟槽间断设置，所述有效谐振区内的压电层通过间断处与所述有效谐振区外的所述压电层相连接。
  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，所述第一电极和所述第二电极均设有所述拱形桥，所述第一电极的拱形桥与所述第二电极的拱形桥相对设置。
  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，所述第一电极或所述第二电极从所述有效谐振区的四周延伸至所述第一衬底上；或，所述第一电极和所述第二电极均从所述有效谐振区的四周延伸至所述第一衬底上。
  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，形成所述第一电极和所述第二电极后，还包括图形化所述第一电极和所述第二电极，使所述第一电极和所述第二电极在所述第一衬底方向上的投影在所述拱形桥的外周相互错开。
  8. 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。
  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。
  10. 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。
  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、碳、聚酰亚胺或光阻剂。
  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，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。
  13. 根据权利要求12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。
  14. 根据权利要求3所述的薄膜体声波谐振器的制造方法，其特征在于，所述承载衬底或所述第一衬底的材料包括半导体材料。
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