WO2021012376A1 - 体声波谐振器的封装方法及封装结构 - Google Patents

体声波谐振器的封装方法及封装结构 Download PDF

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Publication number
WO2021012376A1
WO2021012376A1 PCT/CN2019/107172 CN2019107172W WO2021012376A1 WO 2021012376 A1 WO2021012376 A1 WO 2021012376A1 CN 2019107172 W CN2019107172 W CN 2019107172W WO 2021012376 A1 WO2021012376 A1 WO 2021012376A1
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Prior art keywords
layer
substrate
acoustic wave
bulk acoustic
cavity
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PCT/CN2019/107172
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English (en)
French (fr)
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罗海龙
李伟
齐飞
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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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Priority to JP2021503139A priority Critical patent/JP7297328B2/ja
Publication of WO2021012376A1 publication Critical patent/WO2021012376A1/zh
Priority to US17/197,917 priority patent/US11870410B2/en
Priority to US18/530,746 priority patent/US20240106406A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders; Supports
    • H03H9/10—Mounting in enclosures
    • H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—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
    • H03H9/05—Holders; Supports
    • H03H9/10—Mounting in enclosures
    • H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
    • H03H9/105—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a cover cap mounted on an element forming part of the BAW device
    • 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
    • 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
    • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/174—Membranes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings
    • H10N30/883—Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/42—Piezoelectric device making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49005—Acoustic transducer

Definitions

  • the invention relates to the technical field of radio frequency product packaging, in particular to a packaging method and packaging structure of a bulk acoustic wave resonator.
  • a bulk acoustic resonator includes electrodes that are typically disposed above and/or below the piezoelectric layer. In response to a high frequency signal applied to the electrode, the piezoelectric layer can oscillate.
  • FBAR can be used in a wireless signal transmission system to realize wireless data input and/or output.
  • FBAR can be used in wireless communication devices, wireless power transmitters, filters of wireless sensors, transmitters, receivers, duplexers, and the like.
  • the current conventional bulk acoustic wave resonator packaging process usually includes the following steps:
  • a silicon dioxide layer 200 is grown on a carrier wafer (not shown) through a thermal oxidation process or a chemical vapor deposition process, and a photolithography and etching process is further used to etch and remove a part of the thickness of the dioxide
  • the silicon layer 200 forms a second cavity 2001.
  • the carrier wafer with the second cavity 2001 is combined with the prefabricated carrier wafer with the first cavity 1011, the bulk acoustic wave resonant structure 102 and the first substrate 100
  • the main structures of the resonant cavity are bonded together.
  • the second cavity 2001 is aligned with the first cavity 1011, and the bulk acoustic wave resonant structure 102 is sandwiched between the second cavity (also referred to as the upper cavity) 2001 and the first cavity. Between the cavities (also called lower cavities) 1011.
  • a lower cavity wall 101 is formed on the pre-made first substrate 100, and the bulk acoustic wave resonant structure 102 includes a first electrode (also called a lower electrode) 1021 and a piezoelectric layer 1022 stacked in a first cavity.
  • the second electrode (also referred to as the upper electrode) 1023, and the lower cavity wall 101 are used to form a first cavity 1011 between the first substrate 100 and the first electrode 1021.
  • the gold-gold bonding process includes: first forming a gold layer 201 required for bonding on the silicon dioxide layer 200 on the periphery of the second cavity 2001 by using a metal lift-off technology; and A gold layer 103 required for bonding is formed on the first electrode 1021 and the second electrode 1023 on the periphery of a cavity 1011; then, after the first cavity 1011 and the second cavity 2001 are aligned with each other, they are melted by heating The gold layer 201 and the gold layer 103 form a gold-gold bond.
  • the metal stripping process refers to: after a substrate is coated with a photoresist film, exposed to light, and developed, the photoresist film with a certain pattern is used as a mask, and the photoresist film needs to be evaporated. Then, while removing the photoresist film, the metal on the photoresist film is stripped clean, leaving only the metal of the required pattern on the substrate.
  • the carrier wafer in the bonded structure is removed, so that the remaining silicon dioxide layer 200 is used as a cover plate, and the silicon dioxide layer 200 is perforated to form the exposed bonded structure. Hole 203 in the gold surface.
  • the silicon dioxide layer needs to be deposited and etched on the carrier wafer, and a gold-gold bonding process is required to bond the first cavity 1011 and the second cavity 2001 together , And the carrier wafer needs to be removed after bonding, so the process is complicated and the equipment cost is high. And because the gold-gold bonding process introduces the gold element, there is a problem of high material cost and element pollution to the production line.
  • the passivation layer 205 in the above process is usually formed by depositing a thinner layer of silicon oxide or silicon nitride and other commonly used passivation layer materials, which will result in gaps in the holes 203, making the second cavity 2001
  • the sidewalls of the device are thin, and the mechanical strength of the upper cavity cover is insufficient, which may cause the reliability of the device.
  • the purpose of the present invention is to provide a packaging method and packaging structure of a bulk acoustic wave resonator, which can simplify the process, reduce the cost, can be highly compatible with the main structure of the resonant cavity, and can avoid the problem of element pollution caused by the gold-gold bonding process on the production line.
  • the present invention provides a method for packaging a bulk acoustic wave resonator, which includes the following steps:
  • the resonant cavity main structure includes a first substrate and a bulk acoustic wave resonant structure formed on the first substrate, and a bulk acoustic wave resonant structure is formed between the first substrate and the bulk acoustic wave resonant structure.
  • the main structure of the resonant cavity and the cover of the resonator are bonded together through the elastic bonding material layer, and the elastic bonding material layer loses its elasticity, and the bulk acoustic wave resonant structure is sandwiched between the first Between a substrate and the second substrate and at least partially aligned with the second cavity and the first cavity;
  • a conductive interconnection layer is formed on the surface of the through hole and the surface of the resonator cover at the periphery of the through hole.
  • the present invention also provides a bulk acoustic wave resonator packaging structure, including:
  • the main structure of the resonant cavity includes a first substrate and a bulk acoustic wave resonant structure formed on the first substrate.
  • a first substrate is formed between the first substrate and the bulk acoustic wave resonant structure.
  • a resonator cover includes a second substrate and an elastic bonding material layer that loses its elasticity, the elastic bonding material layer sandwiched between the second substrate and the bulk acoustic wave resonant structure
  • a second cavity is formed in the elastic bonding material layer, the second cavity is at least partially aligned with the first cavity, the resonator cover is also provided with a through hole, the The through hole penetrates the resonator cover on the periphery of the second cavity and exposes the corresponding electrical connection part of the bulk acoustic wave resonant structure;
  • the conductive interconnection layer is formed on the surface of the through hole and the surface of the resonator cover on the periphery of the through hole.
  • an elastic bonding material layer having elasticity is formed on a second substrate, and a second cavity is formed in the elastic bonding material layer, thereby fabricating a resonator cover, and then
  • the elastic bonding material layer on the resonator cover can be used to directly bond the resonator cover to the main structure of the resonator cavity, and the elastic bonding material layer can lose its elasticity, and then a corresponding layer can be formed on the resonator cover.
  • the through hole and the conductive interconnection layer covering the inner surface of the through hole. This process not only has the characteristics of low cost, simple process, and high compatibility with the main structure process of the resonant cavity, but also does not cause pollution problems in the gold-gold bonding process.
  • the packaging scheme of the present invention can realize the bonding between the resonator cover and the main structure of the resonator cavity by pressing the two.
  • the bonding process is simple, and does not affect the performance of the first cavity and the second cavity, and can Using the elasticity of the elastic bonding material layer to make its thickness adapt to the change of the step height of the bulk acoustic wave resonant structure on the periphery of the first cavity, thereby tolerating the bulk acoustic wave resonant structure on the main structure of the resonant cavity on the periphery of the first cavity.
  • There is a certain step height difference in the area and when the resonator cover and the main structure of the cavity are bonded together, not only can the side of the second substrate facing away from the first substrate not be tilted, but it can also make up
  • the step height difference of the bulk acoustic wave resonance structure ensures the reliability and stability of the bonding.
  • a flat process window can be provided for the manufacturing process of the conductive interconnection layer, thereby ensuring the performance of the formed conductive interconnection layer.
  • the main structures required on the resonator cover are all fabricated on the second substrate, thereby minimizing the impact on the first cavity.
  • the same material as the piezoelectric layer in the bulk acoustic wave resonant structure can be used to make the passivation layer, which can be compatible with the first cavity process to the greatest extent, while avoiding the use of other materials to make the passivation layer.
  • the passivation layer fills the through holes, thereby enhancing the mechanical strength of the resonator cover, thereby increasing the supporting force of the sidewall of the second cavity of the resonator, and preventing the deformation of the second cavity from affecting the resonance of the resonator Performance and reliability.
  • an inner wall may be formed on the sidewall of the formed through hole before forming the conductive interconnection layer to compensate for the temperature and humidity drift of the elastic bonding material layer to ensure the second The stability of the cavity and the stability of the bonding between the resonator cover and the main structure of the resonator.
  • FIG. 1 is a schematic cross-sectional structure diagram of a typical packaging structure of a bulk acoustic wave resonator.
  • FIG. 2 is a flowchart of a method for packaging a bulk acoustic wave resonator according to a specific embodiment of the present invention.
  • 3A to 3E are schematic cross-sectional structural diagrams in a method of packaging a bulk acoustic wave resonator according to a specific embodiment of the present invention.
  • FIG. 4 is a schematic cross-sectional structure diagram of the packaging structure of a bulk acoustic wave resonator according to a specific embodiment of the present invention.
  • the present invention provides a method for packaging a bulk acoustic wave resonator, including the following steps:
  • the main structure of the resonant cavity includes a first substrate and a bulk acoustic wave resonant structure formed on the first substrate, between the bulk acoustic wave resonant structure and the first substrate Formed with a first cavity;
  • the patterned passivation layer fills the through hole and exposes a part of the conductive interconnection layer on the surface of the resonator cover at the periphery of the through hole, and is exposed
  • the conductive interconnection layer forms a conductive contact pad.
  • step S1 a first substrate 400 is provided, and a first cavity 402 and a bulk acoustic wave resonant structure 404 are formed on the first substrate 400 to form a resonant cavity main structure 40.
  • the main structure 40 of the resonant cavity can be formed by the following method:
  • a carrier substrate is provided, and an etch stop layer (not shown) is formed on the carrier substrate.
  • the carrier substrate may be a carrier wafer, and the carrier wafer may be any suitable one known to those skilled in the art.
  • the substrate wafer may be, for example, a bare silicon wafer or a ceramic substrate, a quartz or glass substrate, or the like.
  • the etch stop layer can be formed on the carrier wafer by a suitable deposition method (such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition) or thermal oxidation method.
  • the material of the etch stop layer includes but is not limited to At least one of silicon oxide, silicon nitride, silicon oxynitride, fluorocarbon (CF), carbon-doped silicon oxide (SiOC), silicon carbonitride and other materials, the etch stop layer can be subsequently removed from the carrier liner As the process stopping point in the bottom process, the bulk acoustic wave resonance structure is protected, and its thickness is, for example, In other embodiments of the present invention, the etch stop layer may also be a removable film material such as photocurable adhesive or hot melt adhesive, which may be removed when the carrier wafer is subsequently removed.
  • the second electrode material layer (not shown) used to make the second electrode 4043 can be sequentially covered on the surface of the etch stop layer by any suitable method known to those skilled in the art such as evaporation, magnetron sputtering, etc. ,
  • the materials of the first electrode material layer and the second electrode material layer include, but are not limited to, at least one metal of Ag, Au, Cu, Pd, Cr, Mo, Ti, Ta, Sn, W, and Al.
  • the material of the piezoelectric layer 4042 piezoelectric materials with wurtzite crystal structure such as ZnO, AlN, GaN, lead zirconate titanate, lead titanate, etc. can be used.
  • the thickness of the piezoelectric material layer can be set according to the target resonance frequency, for example, set to about 1/2 of the wavelength.
  • the Mo metal film is used as the first electrode material layer and the second electrode material layer.
  • the thickness of the Mo metal film is usually To 1 ⁇ m, using AlN as the piezoelectric material layer, the thickness of AlN usually ranges from To 2 ⁇ m.
  • the bulk acoustic wave resonant structure to be formed may also include other film layers besides the above-mentioned several film layers, which can be set reasonably according to actual device requirements, and there is no specific limitation here.
  • the third lower cavity wall layer 4013 and the second lower cavity can be sequentially formed on the first electrode material layer by a suitable deposition method (such as chemical vapor deposition, physical vapor deposition or atomic layer deposition, etc.) or thermal oxidation process.
  • the body wall layer 4012, the third lower cavity wall layer 4013 may be silicon oxide, and the second lower cavity wall layer 4012 may be silicon nitride or silicon oxynitride.
  • the third lower cavity wall layer 4013 can be used as an etching stop point when the first lower cavity wall layer 4011 is subsequently etched to form the first cavity 402, which can protect the first electrode material layer from unnecessary damage.
  • the second lower cavity wall layer 4012 can be used as a hard mask layer in the subsequent alignment mark opening process, which is beneficial to improve the accuracy of the formed alignment mark opening.
  • the cross section of the alignment mark opening (plane parallel to the surface of the carrier wafer) can be circular, cross, ellipse, polygon, grating, etc.
  • the longitudinal section of the alignment mark opening (vertical to the surface of the carrier wafer)
  • the plane) shape can be rectangular, U-shaped, regular trapezoid, or inverted trapezoid.
  • the position of the alignment mark opening is generally set on the periphery of the first cavity 402 to be formed, for example, on the outside of the contact area of the first electrode and the contact area of the second electrode of the bulk acoustic wave resonator. In specific implementation, it can only be set On the outer side of the bulk acoustic wave resonator to be formed, the outer sides of the bulk acoustic wave resonator may also be arranged in an axisymmetric or center-symmetric manner.
  • the first lower cavity wall layer 4011 can be deposited by a suitable deposition method (such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition, etc.) to fill the alignment mark opening and cover the second lower cavity
  • a suitable deposition method such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition, etc.
  • the deposited first lower cavity wall layer 4011 can not only fill the alignment mark openings, but also need to have a sufficient thickness above the second lower cavity wall layer 4012 to be used later to form the required depth
  • the first lower cavity wall layer 4011 is silicon oxide, which can be made of TEOS or PEOX, and the thickness is selected to be 0.5 ⁇ m-4 ⁇ m.
  • the top of the first lower cavity wall layer 4011 can be flattened (for example, using a chemical mechanical polishing process for flattening) to make its top surface flat.
  • the portion of the first lower cavity wall layer 4011 filled in the alignment mark opening forms an alignment mark 403.
  • the alignment mark is used for subsequent alignment of the second substrate 300 and the first substrate 400 to improve alignment accuracy.
  • the first lower cavity wall layer 4011 to the third lower cavity wall layer 4013 constitute a supporting layer for making the first cavity 402.
  • the cross-section of the first cavity 402 (a cross-section parallel to the surface of the carrier wafer) may be a polygon such as a rectangle or a pentagon, or may be a circle, an ellipse, or the like.
  • first cavities 402 can be formed at the same time, and the remaining first lower cavity wall layers 4011 to third are passed between adjacent first cavities 402.
  • the lower cavity wall layer 4013 is isolated by the laminated structure, and the remaining first lower cavity wall layer 4011 to the third lower cavity wall layer 4013 around the first cavity 402 serve as the subsequent support structure for supporting the bulk acoustic wave resonance structure .
  • the first lower cavity wall layer 4011, the second lower cavity wall layer 4012, and the third lower cavity wall layer 4013 constitute an ONO (oxide layer-silicon nitride-oxide layer) structure, and the stacked ONO structure has low defects
  • the second lower cavity wall layer 4012 made of silicon nitride can trap charges and suppress leakage current.
  • the depth of the first cavity 402 is, for example, 0.5 ⁇ m to 4 ⁇ m.
  • the first substrate 400 can be any suitable carrier material well known to those skilled in the art, for example, it can be at least one of the following materials: Si, Ge, SiGe , SiC, SiGeC, InAs, GaAs, InP, or other III/V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon-on-insulator (SOI), silicon-on-insulator (SSOI), germanium-on-insulator Silicon (S-SiGeOI), silicon germanium-on-insulator (SiGeOI), germanium-on-insulator (GeOI), or double-side polished wafers (DSP), or ceramics such as alumina Substrate, quartz or glass substrate, etc.
  • SOI silicon-on-insulator
  • SSOI silicon-on-insulator
  • SiGeOI germanium-on-insulator Silicon
  • SiGeOI silicon germanium-on-insulator
  • GeOI germanium-on-insulator
  • DSP double-side polished wafer
  • the first substrate 400 can be bonded to the first lower cavity wall layer 4011 by any suitable bonding process known to those skilled in the art, for example, by coating the first substrate 400 with hot melt
  • the side of the first lower cavity wall layer 4011 facing away from the carrier substrate is bonded to the first substrate 400 by means of glue or the like.
  • the first cavity 402 is enclosed between the first substrate 400 and the first electrode material layer used to make the first electrode 4041.
  • vacuum bonding is used to bond the first substrate 400 to the first lower cavity wall layer 4011.
  • the conditions of the vacuum bonding process include: a bonding pressure of 1 Pa to 105 Pa, and a bonding temperature of 150 °C ⁇ 200°C.
  • a suitable process can be selected to remove the carrier substrate.
  • the carrier substrate can be removed by a CMP process or a CMP process.
  • the etching process removes the carrier substrate.
  • the entire structure is inverted so that the first substrate 400 is underneath, and the second electrode material layer for making the second electrode 4043 is on the top, and the first electrode material layer is patterned in sequence through exposure, development, and etching processes.
  • the piezoelectric material layer and the second electrode material layer or the first electrode material layer, the piezoelectric material layer and the second electrode material layer are patterned in sequence to define the first electrode 4041 (that is, the remaining first electrode material layer, also (Referred to as the lower electrode), the piezoelectric layer 4042 (that is, the remaining piezoelectric material layer), and the second electrode 4042 (that is, the remaining second electrode material layer, also called the upper electrode), thereby forming a bulk acoustic wave resonance structure 404.
  • part of the second electrode material layer and the piezoelectric material layer underneath the bulk acoustic wave resonator structure 404 on the outer side of the first cavity 402 can be etched and removed at the same time.
  • the first electrode 4041 is exposed to form an opening 404'.
  • the top view shape of the opening 404' is a semi-circular or closed-circular shape, so that a stepped bulk acoustic wave resonance structure 404 is formed on the periphery of the first cavity 402, and the step height is uniform , Marked as H.
  • the film layer of 404 is patterned to form the bulk acoustic wave resonance structure 404.
  • step S1 the process of providing the resonant cavity main structure 40 in step S1 is completed.
  • a sacrificial layer may be used to directly form the first cavity 402 and the bulk acoustic wave resonant structure 404 on the first substrate 400 to obtain the main structure 40 of the resonant cavity.
  • the specific process includes:
  • the first substrate 400 may include a base (not shown). (Shown) and at least one thin film (not shown) covering the substrate (not shown) may also be a bare chip of semiconductor material.
  • the first cavity 402 is filled with a sacrificial layer (not shown), the top surface of the sacrificial layer is flush with the top surface of the first substrate 400, or may be higher than the top surface of the first substrate 400, It may also be slightly lower than the top surface of the first substrate 400, and the sacrificial layer may have a single-layer structure or a stacked-layer structure.
  • the top surfaces of the first substrate 400 and the sacrificial layer are sequentially covered with a first electrode material layer (not shown) for making the first electrode 4041, a piezoelectric material layer for making the piezoelectric layer 4042, and
  • the second electrode material layer of the second electrode 4043 is fabricated, and the first electrode material layer, the piezoelectric material layer, and the second electrode material layer are sequentially patterned or the second electrode material layer is sequentially patterned through processes such as exposure, development, and etching.
  • the electrode material layer, the piezoelectric material layer, and the first electrode material layer define the first electrode 4041, the piezoelectric layer 4042, and the second electrode 4043, thereby forming a bulk acoustic wave resonance structure 404.
  • a release hole (not shown) is opened on the bulk acoustic wave resonator structure 404 near the edge in the region of the first cavity 402, and the sacrificial layer is removed by introducing an etchant into the release hole to re-empt the groove.
  • a first cavity 402 between the bulk acoustic wave resonance structure 404 and the first substrate 400 is obtained, and the first cavity 402 is a groove structure with the entire bottom recessed in the first substrate 400. So far, the process of providing the resonant cavity main structure 40 in step S1 is completed.
  • another method of using a sacrificial layer to directly form the first cavity 402 and the bulk acoustic wave resonant structure 404 on the first substrate 400 to obtain the main structure 40 of the resonant cavity may be provided.
  • the specific process includes:
  • a sacrificial layer (not shown) is completely covered on the first substrate 400.
  • the sacrificial layer may be a single-layer structure or a stacked-layer structure.
  • the top surfaces of the first substrate 400 and the sacrificial layer are sequentially covered with a first electrode material layer (not shown) for making the first electrode 4041, a piezoelectric material layer for making the piezoelectric layer 4042, and
  • the second electrode material layer of the second electrode 4043 is fabricated, and the first electrode material layer, the piezoelectric material layer, and the second electrode material layer are sequentially patterned or the second electrode material layer is sequentially patterned through processes such as exposure, development, and etching.
  • the electrode material layer, the piezoelectric material layer, and the first electrode material layer define the first electrode 4041, the piezoelectric layer 4042, and the second electrode 4043, thereby forming a bulk acoustic wave resonance structure 404.
  • a release hole (not shown) can be opened on the edge area of the bulk acoustic wave resonant structure 404, and the sacrificial layer is removed by introducing an etchant into the release hole, thereby obtaining the bulk acoustic wave resonant structure 404 and the first substrate
  • the first cavity 402 between 400, the first cavity 402 is protrudingly provided on the first substrate 400. So far, the process of providing the resonant cavity main structure 40 in step S1 is completed.
  • the number of bulk acoustic wave resonant structures 404 on the first substrate 400 is not limited to one, that is, it can be A plurality of bulk acoustic wave resonant structures 404 are formed on the upper surface at the same time.
  • Each bulk acoustic wave resonant structure 404 and the first substrate 400 have a first cavity 402, and the lower cavity wall 401 can pass between adjacent first cavities 402.
  • adjacent BAW resonant structures 404 may be disconnected from each other, or some of the film layers may be connected together.
  • a second substrate 300 is provided.
  • the second substrate 300 may be a substrate including a silicon base, such as a bulk silicon substrate, a silicon-on-insulator substrate, or A substrate composed of a silicon substrate and a silicon dioxide layer laminated on the silicon substrate (the silicon dioxide layer is now arranged facing the bulk acoustic wave resonator structure), so that through-silicon via (TSV) technology can be used later.
  • TSV through-silicon via
  • the material selected for the elastic bonding material layer 301 needs to meet: it can be patterned, can be cured under certain conditions, and can be stably It adheres to the materials of the upper and lower layers and is elastic to tolerate a certain step height difference during subsequent bonding of wafers. Therefore, the material of the elastic bonding material layer 301 may be a light-curing material, a heat-curing material or a light-curing material. The combination of material and heat-curing material can lose its elasticity through light, heating and cooling, for example, a dry film.
  • a fluid dry film photoresist material can be coated by a coating process (such as spin coating, spray coating, roll coating or screen printing) or a solid or semi-solid dry film material can be pressed by a laminating machine.
  • a coating process such as spin coating, spray coating, roll coating or screen printing
  • a solid or semi-solid dry film material can be pressed by a laminating machine.
  • an elastic bonding material layer 301 is formed on the second substrate 300.
  • a solid dry film material is attached to the second substrate 300 at 80°C to 120°C (for example, 110°C) and a vacuum is drawn to form an elastic bonding material layer 301.
  • the elastic bonding material layer 301 may have a three-layer structure, for example, one layer is a PE protective layer, the middle is a dry film layer, and the other layer is a PET protective layer.
  • the PE protective layer is a film layer with a special polyethylene (PE) plastic film as the base material, such as high-density polyethylene protective film, medium-density polyethylene and low-density polyethylene.
  • PE polyethylene
  • the full name of the PET protective layer is polyethylene terephthalate, which is obtained by the condensation polymerization of terephthalic acid and ethylene glycol. Both the PE protective layer and the PET layer only play a protective role and will be removed before lamination and development. Therefore, the intermediate layer of dry film is finally sandwiched between the second substrate 300 and the first substrate 400. It has certain viscosity and good photosensitivity, and the thickness of the elastic bonding material layer 301 is 10 ⁇ m-20 ⁇ m.
  • the elastic bonding material layer 301 is patterned to form the second cavity 302. Specifically, first, a mask is formed on the elastic bonding material layer 301, ultraviolet exposure is performed under vacuum conditions, and the exposure is allowed to stand for a while.
  • the radiation dose of the ultraviolet exposure is, for example, 200J/cm2 ⁇ 300mJ/cm2;
  • the exposed elastic bonding material layer 301 is pre-baked at a temperature of 100°C to 150°C (for example, 130°C) for 100 seconds to 300 seconds (for example, 200 seconds); then, at room temperature, more (For example, three times) the pre-baked elastic bonding material layer 301 is spin-sprayed with a developing solution to develop the pre-baked elastic bonding material layer 301 to form a second cavity 302
  • the developer is PGMEA
  • its components include propylene glycol methyl ether acetate
  • the molecular formula of propylene glycol methyl ether acetate is C6H12O3.
  • the shape and size of the second cavity 302 may be the same as those of the first cavity 402, or not exactly the same, as long as the second cavity 302 can make the first electrode layer of the bulk acoustic wave resonant structure 404 after subsequent bonding 4041, the piezoelectric layer 4042, and the second electrode layer 4042 only need to have portions that overlap with the first cavity 402 and the second cavity 302 at the same time, thereby forming an effective resonance region of the resonator.
  • step S3 in step S3, the opening of the second cavity 302 is placed toward the bulk acoustic wave resonator structure 404 and aligned with the first cavity 402, and the elastic bonding material layer 301
  • the second substrate 300, the bulk acoustic wave resonant structure 404 and the lower cavity wall 401 are bonded together.
  • the bulk acoustic wave resonant structure 404 has an opening 404' exposing part or all of the first electrode 4041 (that is, the first electrical connection portion) in the area outside the first cavity 402, and the opening 404' makes the
  • the bulk acoustic wave resonator structure 404 has a step with a height of H, and the subsequent first through hole will be formed in the area of the opening 404'.
  • the second substrate 300 is pressed by force. And the main structure 40 of the resonant cavity are bonded together (that is, the second substrate 300 is bonded to the bulk acoustic wave resonant structure 404 and the exposed lower cavity wall 401 through the elastic bonding material layer 301),
  • the thickness of the elastic bonding material layer 301 can be adaptively changed with the steps at the opening 404', and at the same time, the surfaces of the second substrate 300 and the first substrate 400 opposite to each other are kept horizontal. At this time, the elastic bonding material layer 301 adapts to the step height difference due to its own elasticity.
  • the first upper cavity wall 3011 is formed with a larger height, and the other part is adhered to the surface of the second electrode 4043 opposite to the first upper cavity wall 3011 on the periphery of the first cavity 402 to form a second upper cavity wall 3011 with a smaller height.
  • the height difference between the upper cavity wall 3012, the first upper cavity wall 3011 and the second upper cavity wall 3012 facing the first substrate 400 is H, the first upper cavity wall 3011 and the second upper cavity wall 3012
  • the side facing the second substrate 300 is flush or nearly flush.
  • the second substrate 300 and the first substrate 400 pass through the viscosity and molecular weight of the first upper cavity wall 3011 and the second upper cavity wall 3012. Bonding force bonds together.
  • This bonding process is simple, does not affect the performance of the first cavity 402 and the second cavity 302, and can tolerate the bulk acoustic wave resonant structure 404 on the first substrate 400 having the area around the first cavity 402 A certain step height difference, so that after the second substrate 300 and the first substrate 400 are bonded together, avoid the step height difference causing the second substrate to tilt on the side facing away from the first substrate And avoid the problem of unreliable bonding caused by the difference in step height.
  • the process conditions for bonding the resonator cover 30 and the main structure 40 of the resonator cavity include: a bonding pressure of 1 Pa to 105 Pa, vacuum bonding, a temperature of 150°C to 200°C (for example, 150°C), and pressure
  • the time is 20min ⁇ 30min, so as to avoid affecting the resonance performance of the product while ensuring the bonding performance.
  • the elastic bonding material layer 301 is cured by light, heating and cooling, that is, the elastic bonding material layer 301 loses its elasticity, so that the resonator cover 30 and the resonant cavity main structure 40 are reliably connected together .
  • the process of curing the elastic bonding material layer 301 can be a high-temperature curing process, where the curing temperature is 180°C to 220°C (for example, 190°C), and the curing time is 1.5 hours to 2 hours (for example, 2 hours).
  • the process of curing the elastic bonding material layer 301 can also be an ultraviolet curing process, and the radiation dose of the ultraviolet curing can be 200mJ/cm2 ⁇ 300mJ/cm2, and the patterned elastic bonding material
  • the light used in the ultraviolet exposure process of the layer 301 is the same to simplify the process and reduce the cost.
  • step S4 first, referring to FIG. 3D, the second substrate 300 is thinned from the side of the second substrate 300 that faces away from the bulk acoustic wave resonator structure 404 through a chemical mechanical polishing (CMP) process
  • CMP chemical mechanical polishing
  • a through-silicon via (TSV) etching process is used to open a hole from the side of the second substrate 300 at the first upper cavity wall 3011 facing away from the bulk acoustic wave resonator structure 404 to penetrate the first upper cavity
  • the wall 3011 exposes a part of the first electrode 4041 at the opening 404', forming a first through hole 3031, from the second substrate 300 at the second upper cavity wall 3012 back to the bulk acoustic wave resonance structure 404
  • a hole is opened on one side to penetrate through the second upper cavity wall 3012 to expose a part of the second electrode 4043, forming a second through hole 3032, wherein the part of the first cavity 402 exposed by the first through hole 3031 is first
  • the electrode 4041 is referred to as the first electrical connection portion
  • the portion of the second electrode 4043 that extends out of the first cavity 402 exposed by the second through hole 3032 is referred to as the second electrical connection portion.
  • the second substrate 300 at the first upper cavity wall 3011 and the first upper cavity wall 3011 may be sequentially etched through exposure, development, and etching processes to form the first through hole 3031 to form the second An etching process of a through hole 3031 until the first electrode 4041 is exposed; then the second substrate 300 and the second upper cavity at the second upper cavity wall 3012 are etched through exposure, development and etching processes
  • the second through hole 3032 is formed by the wall 3012.
  • the second through hole 3032 is etched until the second electrode 4043 is exposed.
  • the second through hole 3032 may be formed before the first through hole 3032 is formed. Pierce through hole 3031.
  • the size of the first through hole 3031 and the second through hole 3032 can be determined according to the electrode range to be exposed and the etching conditions.
  • the opening diameter of the first through hole 3031 and the second through hole 3032 is about 20 ⁇ m to 70 ⁇ m, and the depth of the first through hole 3031 and the second through hole 3032 is about 60 ⁇ m to 100 ⁇ m.
  • the diffusion barrier layer 304 may be deposited including sputtering, plasma physical vapor deposition, high-density plasma chemical vapor deposition, low-pressure chemical vapor deposition, atomic layer deposition, etc., because the deposition
  • the process forms the diffusion barrier layer 304, so the diffusion barrier layer 304 is not only formed on the inner surface of the first through hole 3031 and the second through hole 3032, but also covers the side of the second substrate 300 facing away from the bulk acoustic wave resonance structure 404.
  • the diffusion barrier layer 304 can optionally be a laminated structure, including a nitride layer (not shown) for electrically insulating and isolating the subsequently formed conductive interconnection layer 305 from the second substrate 300 and laminated on the surface of the nitride layer
  • the upper barrier adhesion layer (not shown), the material of the barrier adhesion layer includes at least one of Al, Au, Cr, Co, Ni, Cu, Mo, Ti, Ta, W, Pt and the like.
  • plasma physical vapor deposition, high-density plasma chemical vapor deposition, low-pressure chemical vapor deposition, and atomic layer deposition have better step coverage, which can prevent the formation of the diffusion barrier layer 304 from filling the first through holes 3031 and 3031 and The second through hole 3032.
  • the diffusion barrier layer 304 at the bottom of the first through hole 3031 and the second through hole 3032 is then etched away to expose the first electrode 4041 and the second electrode 4043 on the bottom wall of the first through hole 3031 and the second through hole 3032, At this time, the surface of the second substrate 300 around the first through hole 3031 and the second through hole 3032 is still covered with a diffusion barrier layer to realize the subsequent conductive interconnection in the first through hole 3031 and the second through hole 3032 Electrical insulation between layers.
  • step S5 processes including sputtering, electroplating, plasma physical vapor deposition, high-density plasma chemical vapor deposition, low-pressure chemical vapor deposition, atomic layer deposition, and other processes can be used for through-hole metallization.
  • a conductive interconnection layer 305 covers the diffusion barrier layer 304 and the exposed bottom walls of the first through holes 3031 and the second through holes 3032.
  • the material of 305 can be the same as the material of the second electrode and the first electrode, and the deposition process conditions and the subsequent etching process conditions are also the same, so that the process of step S1 can be compatible to the greatest extent and the process can be simplified.
  • the material of the conductive interconnection layer 305 may include at least one of Ti, Ta, W, Mo, Cu, W and the like. Then, part of the conductive interconnection layer 305 on the surface of the second substrate 300 facing away from the first substrate 400 is removed by exposure, development and etching processes to pattern the conductive interconnection layer 305 to form a patterned conductive interconnection The layer 305 is electrically connected to the second electrode 4043 and the first electrode 4042 respectively.
  • a dry film is used as the elastic bonding material layer, and the performance of the dry film material is not stable enough when the temperature and humidity change, so in order to avoid the temperature and humidity drift of the dry film material As a result, the performance of the second cavity 302 and the bonding performance of the resonator cover 30 and the main structure 40 of the resonator are changed.
  • the diffusion barrier layer is formed. Before 304, an inner wall 308 is formed on the sidewalls of the first through hole 3031 and the second through hole 3032 through material deposition and etching processes.
  • the material of the inner wall 308 is different from the elastic bonding material layer 301 and used To compensate the temperature and humidity drift of the elastic bonding material layer 301.
  • the material of the inner wall 308 is, for example, silicon dioxide, silicon nitride, silicon oxynitride, or TEOS (Ethyl Orthosilicate).
  • the inner wall 308 can maintain the final height of the elastic bonding material layer 303, and prevent the temperature and humidity drift of the elastic bonding material layer 301 from affecting the performance of the second cavity 302 and the bond between the resonator cover 30 and the main structure 40 of the cavity. Combined stability and reliability.
  • step S6 firstly, processes including sputtering, electroplating, plasma physical vapor deposition, high-density plasma chemical vapor deposition, low-pressure chemical vapor deposition, atomic layer deposition, etc. can be used.
  • a through hole 3031 and a second through hole 3032 and the conductive interconnection layer 305 on the surface of the second substrate 300 facing away from the first substrate 400 and the second substrate 300 are exposed by the conductive interconnection layer 305
  • a passivation layer 306 is deposited on the surface. The thickness of the deposited passivation layer 306 is sufficient to fill the first through hole 3031 and the second through hole 3032.
  • the material of the passivation layer 306 can be the same as that of the piezoelectric layer 4042.
  • the passivation layer 306 is patterned by exposure, development, and etching processes to form the contact opening 307, wherein the process conditions for the patterned passivation layer 306 can be exactly the same as the process conditions for the patterned piezoelectric layer 402, thus Compatible with the process of the main structure 40 of the resonant cavity to the greatest extent, the contact opening 307 can expose a part of the conductive interconnection layer 306 on the surface of the second substrate 300 facing away from the first substrate 400 to form a conductive contact pad (pad ) 3051, the conductive contact pad 3051 includes a conductive contact pad electrically connected to the first electrode 4041 and a conductive contact pad electrically connected to the second electrode 4043.
  • the passivation layer 306 also fills the first through hole 3031 and the second through hole 3032 to enhance the mechanical support performance of the upper cavity wall 301.
  • steps S1 and S2 can also be performed at the same time, or step S2 is performed first and then step S1 is performed.
  • conventional passivation materials may also be used to form the passivation layer 306. These conventional passivation materials include silicon oxide, silicon nitride, silicon oxynitride, metal nitride, and polymers. At least one of them.
  • the packaging method of the bulk acoustic wave resonator of the present invention not only has the characteristics of low cost, simple process, and high compatibility with the process of the main structure of the resonant cavity, but also does not cause pollution problems in the gold-gold bonding process.
  • the bulk acoustic wave resonance structure can tolerate a certain step height difference on the outer region of the first cavity, thereby ensuring the reliability and stability of the bonding.
  • the main structures required on the resonator cover are all completed on the second substrate, the influence on the first cavity can be minimized.
  • an embodiment of the present invention also provides a bulk acoustic wave resonator packaging structure manufactured by using the bulk acoustic wave resonator packaging method of the present invention.
  • the packaging structure of the bulk acoustic wave resonator includes a resonant cavity main structure 40 and a resonator cover 30.
  • the resonant cavity main structure 40 includes a first substrate 400, a bulk acoustic wave resonator structure 404, and a first cavity 402.
  • the resonator cover includes a second substrate 300, an elastic bonding material layer 301 that has lost elasticity, a second cavity 302, a first through hole 3031 and a second through hole 3032, a conductive interconnect layer 305, and a patterned passivation ⁇ 306.
  • the bulk acoustic wave resonant structure 404 is formed on the first substrate 400, and the first cavity 402 is sandwiched between the bulk acoustic wave resonant structure 404 and the first substrate 400.
  • the second substrate 300 is disposed above the bulk acoustic wave resonant structure 404, the elastic bonding material layer 301 is sandwiched between the second substrate 300 and the bulk acoustic wave resonant structure 404, and the second cavity 302 is formed in The elastic bonding material layer 301 is sandwiched between the second substrate 300 and the bulk acoustic wave resonant structure 404, and the second cavity 302 and the first cavity 402 are at least partially alignment.
  • the first through hole 3031 and the second through hole 3032 are both located at the periphery of the first cavity 402 and the second cavity 302, and both pass through the resonator cover 40 and expose the bulk acoustic wave
  • the resonant structure 404 corresponds to the electrical connection part.
  • the conductive interconnection layer 305 covers the inner surfaces (including the side walls and the bottom wall) of the first through hole 3031 and the second through hole 3032, and continuously extends from the side walls of the first through hole 3031 and the second through hole 3032 to
  • the second substrate 300 faces away from the bulk acoustic wave resonator structure 404 on a part of the surface, that is, the conductive interconnection layer 305 is formed on the inner surface of the first through hole 3031 and the second through hole 3032 and the first
  • the through hole 3031 and the second through hole 3032 are on the surface of the resonator cover.
  • the patterned passivation layer 306 fills the first through hole 3031 and the second through hole 3032 and covers a part of the conductive interaction on the surface of the second substrate 300 facing away from the bulk acoustic wave resonator structure 404.
  • the connection layer 305, and the conductive interconnection layer 305 exposed by the patterned passivation layer 306 forms a corresponding conductive contact pad.
  • the bulk acoustic wave resonant structure 404 has a first electrode 4041, a piezoelectric layer 4042, and a second electrode 4043 that are sequentially stacked on the first substrate 400, and a first cavity 402 is formed in the Between the first substrate 400 and the first electrode 4041, the first cavity 402 is enclosed by the lower cavity wall 401.
  • the lower cavity wall 401 is a support layer different from the material of the first substrate 400 and the bulk acoustic wave resonant structure 404 (ie, 3E and the first lower cavity wall layer 4011 to the third The lower cavity wall layer 4013), the first substrate 400 and the bulk acoustic wave resonant structure 400 are bonded together through the support layer, and the first cavity 402 is formed in the support layer.
  • the bonding material layer 301 is formed on the support layer around the first cavity 402.
  • the first cavity 402 may be a groove structure with the entire bottom recessed in the first substrate 400. In this case, the lower cavity wall 401 is the first cavity around the groove.
  • Substrate 400 or, the first cavity 402 is a cavity structure protruding on the surface of the first substrate 400 as a whole, in both cases, the elastic bonding material layer 302 is formed in the first cavity On the first substrate 400 on the periphery of the cavity 402.
  • the first through hole 402 faces away from the second substrate 300 toward the bulk acoustic wave.
  • the surface of the resonant structure 404 penetrates to expose a part of the surface of the first electrode 4041
  • the second through hole 3032 penetrates from the surface of the second substrate 300 away from the bulk acoustic wave resonant structure 404 to expose a part of the surface The surface of the second electrode 4043.
  • the electrical connection portion of the BAW resonant structure 404 includes: a first electrical connection portion, including a part of the first electrode 4041 extending out of the first cavity; and a second electrical connection portion, including a second electrical connection portion extending out of the first cavity. Part of the second electrode 4043 in a cavity.
  • the patterned passivation layer 306 covering the surface of the second substrate 300 facing away from the bulk acoustic wave resonator structure 404 has a contact opening 307 that exposes the conductive interaction in the corresponding area.
  • the part of the conductive interconnection layer 305 exposed by the contact opening 307 forms a conductive contact pad 3051.
  • the conductive interconnection layer 305 is electrically connected to the second electrode 4043 and the first electrode 4041, respectively, for connecting the second electrode The 4043 and the first electrode 4041 are led out through the corresponding conductive contact pad 3051.
  • the second substrate 300 includes a silicon substrate, such as a bare silicon substrate, so that the first through-holes 3031 and the second through-holes 3032 can be fabricated through a silicon via process.
  • the material selected for the elastic bonding material layer 301 needs to meet the following requirements: it can be patterned, can be cured under certain conditions, can stably adhere to the upper and lower layers of materials, and has elasticity to be able to bond crystals later. A certain step height difference is tolerated when round. Therefore, the material of the elastic bonding material layer 301 can be a photocurable material, a thermal curing material, or a combination of a photocuring material and a thermal curing material, which can be cooled by light and heating. Loss of elasticity, such as dry film.
  • the bulk acoustic wave resonant structure 404 has an opening 404' in the periphery of the first cavity 402 that exposes a part of the first electrode 4041, and the shape of the opening 404' is a closed ring or semi-ring Etc., the height of the steps formed by the bulk acoustic wave resonator structure 404 at the opening 404' is uniform, and all are H; the elastic bonding material layer 301 between the second substrate 300 and the first substrate 400 The thickness can adapt to the step height of the bulk acoustic wave resonator structure 404, and at the same time can maintain the surface level of the second substrate 300 and the first substrate 400 facing away from each other, so as to facilitate the formation of the bulk acoustic wave resonator product and Other products are integrated on the same printed circuit board.
  • an inner wall 308 is formed on the side walls of the first through hole 3031 and the second through hole 3032, and the inner wall 308 is sandwiched between the elastic bonding material layer 301 And the conductive interconnection layer 305, and the inner wall 308 is different from the elastic bonding material layer 301 and used to compensate for the temperature and humidity drift of the elastic bonding material layer 301 to ensure the second air The stability of the cavity and the stability of the bonding between the second substrate and the first substrate.
  • the passivation layer 306 and the piezoelectric layer 4042 are made of the same material, and the deposition process and etching process are also the same to maximize compatibility with the first cavity process, and at the same time Avoid the problem of temperature drift and the introduction of unnecessary stress caused by using other materials to make the passivation layer, thereby improving the resonance performance of the resonator.
  • conventional passivation materials can also be used to form the passivation layer 306. These conventional passivation materials include silicon oxide, silicon nitride, silicon oxynitride, metal nitride, and polymer. At least one of them.
  • an alignment mark 403 is also formed in the lower cavity wall 401 between the first substrate 400 and the first electrode 4041 for enclosing the first cavity 402, so The alignment mark 403 penetrates the bulk acoustic wave resonant structure 404 and is bonded to the elastic bonding material layer 301.
  • the packaging structure of the bulk acoustic wave resonator of this embodiment is made by the packaging method of the bulk acoustic wave resonator of the present invention, the material, size and other parameters of each structure can refer to the above-mentioned bulk acoustic wave resonance.
  • the content of the packaging method of the device is not repeated here.
  • the packaging structure of the bulk acoustic wave resonator of the present invention can improve the resonance performance of the resonator, and can be manufactured by the packaging method of the bulk acoustic wave resonator of the present invention to simplify the process and reduce the cost.

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Abstract

一种体声波谐振器的封装方法及封装结构，通过在第二衬底(300)上形成具有第二空腔(302)的弹性键合材料层(301)，由此来制作谐振器盖体(30)，然后可以通过这个谐振器盖体(30)上的弹性键合材料层(301)来使得谐振器盖体(30)与谐振腔主体结构(40)直接键合，并使得弹性键合材料层(301)失去弹性，之后可以在谐振器盖体(30)上形成穿通孔(3031,3032)以及覆盖在穿通孔(3031,3032)内表面上的导电互连层(305)。此种工艺不仅具有低成本、工艺简单以及跟谐振腔主体结构工艺高度相容的特点，不会造成金-金键合工艺的污染问题，能最大限度地降低对第一空腔(402)的影响，且可以在键合过程中利用弹性键合材料层(301)的弹性来容忍体声波谐振结构(404)在第一空腔(402)外围的区域上具有一定的台阶高度差异，能够保证键合的可靠性和稳定性。

Description

体声波谐振器的封装方法及封装结构 技术领域
本发明涉及射频产品封装技术领域，尤其涉及一种体声波谐振器的封装方法及封装结构。
背景技术
体声波谐振器(FBAR)包括典型地设置在压电层之上和/或之下的电极。响应于施加到电极的高频信号，压电层可以振荡。FBAR可以用于无线信号传输系统，以实现无线数据的输入和/或输出。例如，FBAR可以用在无线通信装置、无线功率发射器、无线传感器的滤波器、发射器、接收器、双工器等中。
请参考图1，目前常规的体声波谐振器的封装工艺通常包括以下步骤：
(1)通过热氧化工艺或化学气相沉积工艺，在载体晶圆(未图示)上生长二氧化硅层200，并进一步通过光刻、刻蚀工艺，刻蚀去除部分厚度的所述二氧化硅层200而形成第二空腔2001。
(2)通过金-金键合(Au-Au bonding)工艺，将具有第二空腔2001的载体晶圆与预先制作好的具有第一空腔1011、体声波谐振结构102和第一衬底100的谐振腔主体结构键合在一起，此时第二空腔2001与第一空腔1011对准，并将体声波谐振结构102夹设在第二空腔(也称为上空腔)2001和第一空腔(也称为下空腔)1011之间。一般的，预先制作好的第一衬底100上形成有下腔体壁101，体声波谐振结构102包括第一空腔堆叠设置的第一电极(也称为下电极)1021、压电层1022、第二电极(也称为上电极)1023，下腔体壁101用于在第一衬底100和第一电极1021之间形成第一空腔1011。具体的，金-金键合工艺过程包括：首先采用金属剥离工艺(metal lift-off technology)在第二空腔2001外围的二氧化硅层200上形成键合所需的金层201，以及，在第一空腔1011外围的第一电极1021和第二电极1023上形成键合所需的金层103；然后在第一空腔1011和第二空腔2001相互对准后，通过加热的方式，融化金层201和金层103而形成金-金键合。其中金属剥离工艺是指：一基片经过涂覆光致抗蚀剂膜、曝光、显影后，以具有一定图形的光致抗蚀剂膜为掩模，带光致抗蚀剂膜蒸发所需的金属，然后在去除光致抗蚀剂膜的同时，把光致抗蚀剂膜上的金属一起 剥离干净，在基片上只剩下所需图形的金属。
(3)利用背面减薄工艺，将键合后的结构中的载体晶圆去除，使得剩余的二氧化硅层200作为盖板，并对二氧化硅层200打孔从而形成暴露出键合的金表面的孔203。
(4)在二氧化硅层200和孔203的表面上电镀铜金属层204，并通过光刻、腐蚀等工艺将铜金属层204图形化，形成将第二电极1023和第一电极1021向外引出的导线。
(5)在二氧化硅层200和铜金属层204上沉积钝化层205，并通过光刻、腐蚀等工艺将钝化层205图形化，以暴露出部分铜金属层204而作为金属焊盘，且进一步在暴露出的铜金属层204处焊球，使得形成的焊球206与金属焊盘相接触。
上述的体声波谐振器的封装工艺中，由于需要在载体晶圆上沉积、刻蚀二氧化硅层，并需要采用金-金键合工艺使第一空腔1011与第二空腔2001键合在一起，且在键合后需要去除载体晶圆，因此工艺复杂，设备成本较高。并且因为金-金键合工艺引入了金元素，所以存在材料成本高且会对产线造成元素污染的问题。另外，上述工艺中的钝化层205通常是沉积较薄一层的氧化硅或氮化硅等常用的钝化层材料而形成，这会导致孔203处仍有间隙，使得第二空腔2001的侧壁较薄，进而造成上腔盖的机械强度不够，会导致器件可靠性风险。
发明内容
本发明的目的在于提供一种体声波谐振器的封装方法及封装结构，能够简化工艺，降低成本，能够与谐振腔主体结构高度兼容且能避免金-金键合工艺对产线造成元素污染的问题。
为了实现上述目的，本发明提供一种体声波谐振器的封装方法，包括以下步骤：
提供谐振腔主体结构，所述谐振腔主体结构包括第一衬底以及形成在所述第一衬底上的体声波谐振结构，所述第一衬底和所述体声波谐振结构之间形成有第一空腔；
提供第二衬底，在所述第二衬底上形成具有第二空腔的弹性键合材料层，以形成谐振器盖体；
通过所述弹性键合材料层将所述谐振腔主体结构和所述谐振器盖体键合在一起并使得所述弹性键合材料层失去弹性，且所述体声波谐振结构夹在所述第一衬底和所述第二衬底之间且所述第二空腔和所述第一空腔至少部分对准；
形成穿过所述谐振器盖体并暴露出所述体声波谐振结构的相应的电连接部的穿通孔；以及，
形成导电互连层于所述穿通孔的表面以及所述穿通孔外围的部分所述谐振器盖体的表面上。
基于同一发明构思，本发明还提供一种体声波谐振器的封装结构，包括：
谐振腔主体结构，所述谐振腔主体结构包括第一衬底以及形成在所述第一衬底上的体声波谐振结构，所述第一衬底和所述体声波谐振结构之间形成有第一空腔；
谐振器盖体，所述谐振器盖体包括第二衬底以及失去弹性的弹性键合材料层，所述弹性键合材料层夹在所述第二衬底和所述体声波谐振结构之间，所述弹性键合材料层中形成有第二空腔，所述第二空腔与所述第一空腔至少有部分对准，所述谐振器盖体上还设有穿通孔，所述穿通孔穿过所述第二空腔外围的谐振器盖体，并暴露出所述体声波谐振结构相应的电连接部；以及，
导电互连层，所述导电互连层形成于所述穿通孔的表面以及所述穿通孔外围的部分所述谐振器盖体的表面上。
与现有技术相比，本发明的技术方案具有以下有益效果：
1、本发明的方案中，通过在第二衬底上形成具有弹性的弹性键合材料层，所述弹性键合材料层中形成有第二空腔，由此来制作谐振器盖体，然后可以通过这个谐振器盖体上的弹性键合材料层来使得谐振器盖体与谐振腔主体结构直接键合，并使得弹性键合材料层失去弹性，之后可以在谐振器盖体上形成相应的穿通孔以及覆盖在穿通孔内表面上的导电互连层。此种工艺不仅具有低成本、工艺简单以及跟谐振腔主体结构工艺高度相容的特点，还不会造成金-金键合工艺的污染问题。
2、本发明的方案中，由于谐振器盖体和谐振腔主体结构键合时的主要接触区域为第二空腔外围的弹性键合材料层，且弹性键合材料层具有一定的弹性，所以本发明的封装方案可以通过将谐振器盖体和谐振腔主体结构压合的方式实现两者的键合，键合工艺简单，不会影响第一空腔和第二空腔的性能，且能够 利用弹性键合材料层的弹性来使其厚度能适应体声波谐振结构在第一空腔外围的台阶高度而变化，由此容忍谐振腔主体结构上的体声波谐振结构在第一空腔外围的区域上具有一定的台阶高度差异，进而在所述谐振器盖体和谐振腔主体结构键合在一起时，不但能使得第二衬底背向第一衬底的一面不发生倾斜，还能补足所述体声波谐振结构的台阶高度差异，保证键合的可靠性和稳定性。而且因为第二衬底背向第一衬底的一面水平，可以为导电互连层的制作工艺提供平坦的工艺窗口，进而保证形成的导电互连层的性能。
3、本发明的方案中，谐振器盖体上所需的主要结构均是在第二衬底上制作完成的，由此，最大限度地降低了对第一空腔的影响。
4、本发明的方案中，可以选择采用与体声波谐振结构中的压电层相同的材质制作做钝化层，能够最大限度兼容第一空腔工艺，同时还能避免使用其他材料来制作钝化层时引起的温度漂移的问题以及引入不必要的应力的问题，由此提高谐振器的谐振性能。另外，钝化层填满穿通孔，由此可以增强谐振器盖体的机械强度，进而提高谐振器的第二空腔的侧壁的支撑力，防止第二空腔变形而影响谐振器的谐振性能和可靠性。
5、本发明的方案中，可以选择在形成导电互连层之前，先在形成的穿通孔的侧壁上形成内侧墙，以补偿所述弹性键合材料层的温湿度漂移，以保证第二空腔的稳定性以及谐振器盖体和谐振腔主体结构键合的稳定性。
附图说明
图1是一种典型的体声波谐振器的封装结构的剖面结构示意图。
图2是本发明具体实施例的体声波谐振器的封装方法流程图。
图3A至图3E是本发明具体实施例的体声波谐振器的封装方法中的剖面结构示意图。
图4是本发明具体实施例的体声波谐振器的封装结构的剖面结构示意图。
其中，附图标记如下：
100、400-第一衬底；101、401-下腔体壁；1011、402-第一空腔；102、404-体声波谐振结构；404’-体声波谐振结构的开口；1021、4041-第一电极；102、4042-压电层；1023、4043-第二电极；103、201-金层；200-二氧化硅层；2001、302-第二空腔；孔-203；204-铜金属层；205-钝化层；206-焊球；40-谐振腔主体 结构；4011-第一下腔体壁层；4012-第二下腔体壁层；4013-第三下腔体壁层；403-对准标记；30-谐振器盖体；300-第二衬底；301-弹性键合材料层；3011-第一上腔体壁；3012-第二上腔体壁；H-高度差；3031-第一穿通孔；3032-第二穿通孔；304-扩散阻挡层；305-导电互连层；3051-导电接触垫；306-钝化层；307-接触开口；308-内侧墙。
具体实施方式
以下结合附图和具体实施例对本发明的技术方案作进一步详细说明。根据下面的说明，本发明的优点和特征将更清楚。需说明的是，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。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。
请参考图2，本发明提供一种体声波谐振器的封装方法，包括以下步骤：
S1，提供谐振腔主体结构，所述谐振腔主体结构包括第一衬底以及形成在所述第一衬底上的体声波谐振结构，所述体声波谐振结构和所述第一衬底之间形成有第一空腔；
S2，提供第二衬底，在所述第二衬底上形成具有第二空腔的弹性键合材料层，以形成谐振器盖体；
S3，通过所述弹性键合材料层将所述谐振腔主体结构和所述谐振器盖体键合在一起并使得所述弹性键合材料层失去弹性，且键合后，所述体声波谐振结构夹在所述第一衬底和所述第二衬底之间，所述第二空腔和所述第一空腔至少部分对准；
S4，形成穿过所述谐振器盖体并暴露出所述体声波谐振结构的相应的电连接部的穿通孔；
S5，形成导电互连层于所述穿通孔的表面以及所述穿通孔外围的部分所述谐振器盖体的表面上；以及，
S6，形成图形化的钝化层，所述图形化的钝化层填满所述穿通孔并暴露出 所述穿通孔外围的谐振器盖体表面上部分所述导电互连层，被暴露出的所述导电互连层形成导电接触垫。
请参考图3A，在步骤S1中，提供第一衬底400，并在第一衬底400上形成第一空腔402和体声波谐振结构404，以形成谐振腔主体结构40。
具体实施时，可通过如下方法形成谐振腔主体结构40：
首先，提供载体衬底，在所述载体衬底上形成刻蚀停止层(未图示)，该载体衬底可以是一载体晶圆，载体晶圆可以是本领域技术人员熟知的任意合适的衬底晶圆，例如可以是裸硅片或者陶瓷基底、石英或玻璃基底等。所述刻蚀停止层可以通过适合的沉积方法(例如化学气相沉积、物理气相沉积或原子层沉积等)或热氧化方法形成于载体晶圆上，所述刻蚀停止层的材料包括但不限于氧化硅、氮化硅、氮氧化硅、碳氟化合物(CF)、掺碳氧化硅(SiOC)、碳氮化硅等材料中的至少一种，所述刻蚀停止层可以在后续去除载体衬底工艺中作为工艺停止点，保护体声波谐振结构，其厚度例如为
Figure PCTCN2019107172-appb-000001
在本发明的其他实施例中，所述刻蚀停止层还可以是光固化胶或热熔胶等可去除的膜层材料，可在后续去除载体晶圆时一并去除。
接着，可以通过蒸镀、磁控溅射等本领域技术人员熟知的任何适合的方法在刻蚀停止层的表面上依次覆盖用于制作第二电极4043的第二电极材料层(未图示)、用于制作压电层4042的压电材料层、用于制作第一电极4041的第一电极材料层，以形成用于制作体声波谐振结构404的膜层。其中，第一电极材料层和第二电极材料层的材料包括但不限于Ag、Au、Cu、Pd、Cr、Mo、Ti、Ta、Sn、W和Al中的至少一种金属。压电层4042的材料可以使用ZnO、AlN、GaN、锆钛酸铅、钛酸铅等具有纤锌矿型结晶结构的压电材料。对于压电材料层的厚度，可以根据目标谐振频率来设定，例如设定为波长的1/2左右。本实施例中，使用Mo金属薄膜作为第一电极材料层和第二电极材料层，Mo金属薄膜厚度通常为
Figure PCTCN2019107172-appb-000002
到1μm，使用AlN作为压电材料层，AlN厚度范围通常为
Figure PCTCN2019107172-appb-000003
到2μm。在本发明的其他实施例中，待形成的体声波谐振结构还可以包括上述几种膜层之外的其他膜层，可根据实际的器件需要进行合理设置，在此并不做具体限制。
然后，可以通过适合的沉积方法(例如化学气相沉积、物理气相沉积或原子层沉积等)或热氧化工艺等在第一电极材料层上依次形成第三下腔体壁层 4013和第二下腔体壁层4012，第三下腔体壁层4013可以是氧化硅，第二下腔体壁层4012可以是氮化硅或氮氧化硅。第三下腔体壁层4013可以作为后续刻蚀第一下腔壁层4011形成第一空腔402时刻蚀停止点，能够保护第一电极材料层不受到不必要的损伤。第二下腔体壁层4012可以作为后续对准标记开口工艺中的硬掩膜层，有利于提高形成的对准标记开口的精度。
接着，执行曝光、显影、刻蚀工艺，依次刻蚀第二下腔体壁层4012、第三下腔体壁层4013、第一电极材料层、压电材料层及第二电极材料层，刻蚀停止在载体晶圆的表面上(如果形成有刻蚀停止层，则停止在载体晶圆表面上的刻蚀停止层上)，从而形成相应的对准标记开口(未图示)。对准标记开口的横截面(平行于载体晶圆表面的平面)形状可以为圆形、十字形、椭圆形、多边形、光栅形等，对准标记开口的纵向剖面(垂直于载体晶圆表面的平面)形状可以是矩形、U形、正梯形或倒梯形等。对准标记开口的位置一般设置于待形成的第一空腔402的外围，例如位于体声波谐振器的第一电极的接触区域和第二电极的接触区域的外侧，具体实施时，可以仅设置在待形成的体声波谐振器的外围一侧，也可以以轴对称或中心对称的方式设置体声波谐振器的外围两侧。
然后，可以通过适合的沉积方法(例如化学气相沉积、物理气相沉积或原子层沉积等)沉积第一下腔体壁层4011，使其填充于对准标记开口中并覆盖在第二下腔体壁层4012上，沉积的第一下腔体壁层4011不仅能够填满对准标记开口，还需要在第二下腔体壁层4012上方具有足够的厚度，以在后续用于形成所需深度的第一空腔402。本实施例中，第一下腔体壁层4011为氧化硅，可以采用TEOS或者PEOX等材料，厚度选为0.5μm～4μm。在覆盖第一下腔体壁层4011之后，可以对第一下腔体壁层4011进行顶部平坦化(例如是采用化学机械研磨工艺进行平坦化)，以使其顶面平坦，由此，一方面有利于提高后续形成的第一空腔工艺精度以及形成第一空腔的深度均一性，另一方面能够有利于后续的第一衬底400的键合。如图3A所示，第一下腔体壁层4011填满在对准标记开口中的部分形成对准标记403。对准标记用于后续的第二衬底300和第一衬底400的对准，以提高对准精度。第一下腔体壁层4011至第三下腔体壁层4013组成用于制作第一空腔402的支撑层。
接着，执行曝光、显影、刻蚀工艺，刻蚀第一下腔体壁层4011至第三下腔体壁层4013，而形成第一空腔402，第一下腔体壁层4011至第三下腔体壁层4013 共同作为围成所述第一空腔402的下腔体壁。所述第一空腔402的横截面(平行于载体晶圆表面的截面)可以为矩形、五边形等多边形，也可以是圆形、椭圆形等。当需要在同一衬底上制作多个体声波谐振器时，可以同时形成多个第一空腔402，相邻的第一空腔402之间通过剩余的第一下腔体壁层4011至第三下腔体壁层4013的叠层结构来隔离，第一空腔402周围剩余的第一下腔体壁层4011至第三下腔体壁层4013作为后续用于支撑体声波谐振结构的支撑结构。第一下腔体壁层4011、第二下腔体壁层4012、第三下腔体壁层4013组成ONO(氧化层-氮化硅-氧化层)结构，堆叠的ONO结构具有较低的缺陷，其中氮化硅材质的第二下腔体壁层4012可以捕获电荷，抑制漏电流。第一空腔402的深度例如为0.5μm～4μm。
接着，提供第一衬底400，所述第一衬底400可以是本领域技术人员熟知的任意合适的载体材料，例如可以是以下所提到的材料中的至少一种：Si、Ge、SiGe、SiC、SiGeC、InAs、GaAs、InP或者其它III/V化合物半导体，还包括这些半导体构成的多层结构等，或者为绝缘体上硅(SOI)、绝缘体上层叠硅(SSOI)、绝缘体上层叠锗化硅(S-SiGeOI)、绝缘体上锗化硅(SiGeOI)以及绝缘体上锗(GeOI)，或者还可以为双面抛光硅片(Double Side Polished Wafers，DSP)，也可为氧化铝等的陶瓷基底、石英或玻璃基底等。
然后，可以通过本领域技术人员熟知的任意合适的键合工艺，将第一衬底400键合到第一下腔体壁层4011上，例如可以通过在第一衬底400上涂敷热熔胶等方式，将第一下腔体壁层4011背向载体衬底的一面键合第一衬底400上。由此，将第一空腔402封闭在第一衬底400和用于制作第一电极4041的第一电极材料层之间。再例如采用真空键合的方式将第一衬底400键合到第一下腔体壁层4011上，所述真空键合工艺的条件包括：键合压力为1Pa～105Pa，键合温度为150℃～200℃。
接着，可以根据载体衬底(即载体晶圆)的材质特性，选择合适的工艺去除载体衬底，例如，当所述载体衬底为裸硅片时，可以通过CMP工艺或者通过CMP工艺结合湿法刻蚀的工艺去除载体衬底。
然后，倒置整个结构，使得第一衬底400在下，用于制作第二电极4043的第二电极材料层在上，并通过曝光、显影、刻蚀工艺，来依次图案化第一电极材料层、压电材料层和第二电极材料层或者依次图案化第一电极材料层、压电 材料层和第二电极材料层，以此定义出第一电极4041(即剩余的第一电极材料层，也称为下电极)、压电层4042(即剩余的压电材料层)和第二电极4042(即剩余的第二电极材料层，也称为上电极)，由此形成体声波谐振结构404。在此工艺中，可以同时刻蚀去除第一空腔402外围一侧的体声波谐振结构404中的部分第二电极材料层及其下方的压电材料层和部分厚度的对准标记403，以暴露出第一电极4041，从而形成开口404’，开口404’的俯视形状为半环形或者闭合环形，如此一来在第一空腔402外围形成具有台阶的体声波谐振结构404，且台阶高度均匀，记为H。需要说明的是，在本发明的其他实施例中，也可以在用于制作体声波谐振结构404的膜层上形成第三下腔体壁层4013之前，将所述用于制作体声波谐振结构404的膜层图形化，以形成所述体声波谐振结构404。
至此，完成了步骤S1中提供谐振腔主体结构40的工艺过程。
在本发明的其他实施例中，也可以不利用载体晶圆而是利用牺牲层来直接在第一衬底400上形成第一空腔402和体声波谐振结构404，以获得谐振腔主体结构40，具体过程包括：
首先，刻蚀去除第一衬底400部分区域中的部分厚度，以形成用于制作第一空腔402的凹槽(未图示)，此处，第一衬底400可以包括基底(未图示)以及覆盖在基底(未图示)上的至少一层薄膜(未图示)，也可以是半导体材质的裸片。
接着，在第一空腔402中填满牺牲层(未图示)，该牺牲层的顶面与第一衬底400的顶面齐平，也可以高于第一衬底400的顶面，也可以略低于第一衬底400的顶面，该牺牲层可以是单层结构，也可以是叠层结构。
之后，在第一衬底400和牺牲层的顶面上依次覆盖用于制作第一电极4041的第一电极材料层(未图示)、用于制作压电层4042的压电材料层、用于制作第二电极4043的第二电极材料层，并通过曝光、显影和刻蚀等工艺，来依次图案化第一电极材料层、压电材料层和第二电极材料层或者依次图案化第二电极材料层、压电材料层和第一电极材料层，以定义出第一电极4041、压电层4042和第二电极4043，由此，形成体声波谐振结构404。
然后，在第一空腔402区域中且靠近边缘处的体声波谐振结构404上开释放孔(未图示)，通过向释放孔中引入刻蚀剂来去除牺牲层，以重新清空凹槽，由此获得了体声波谐振结构404和第一衬底400之间的第一空腔402，第一空腔 402为整个底部凹陷在所述第一衬底400中的凹槽结构。至此，完成了步骤S1中提供谐振腔主体结构40的工艺过程。
在本发明的其他实施例中，还可以提供另外一种利用牺牲层来直接在第一衬底400上形成第一空腔402和体声波谐振结构404，以获得谐振腔主体结构40的方法，其具体过程包括：
首先，在第一衬底400上全面覆盖牺牲层(未图示)，牺牲层可以是单层结构，也可以是叠层结构。
然后，执行曝光、显影、刻蚀工艺，刻蚀牺牲层以使其图形化，以形成用于制作第一空腔402的图形化的牺牲层；
接着，在第一衬底400和牺牲层的顶面上依次覆盖用于制作第一电极4041的第一电极材料层(未图示)、用于制作压电层4042的压电材料层、用于制作第二电极4043的第二电极材料层，并通过曝光、显影和刻蚀等工艺，来依次图案化第一电极材料层、压电材料层和第二电极材料层或者依次图案化第二电极材料层、压电材料层和第一电极材料层，以定义出第一电极4041、压电层4042和第二电极4043，由此，形成体声波谐振结构404。
然后，可以在体声波谐振结构404的边缘区域上开释放孔(未图示)，通过向释放孔中引入刻蚀剂来去除牺牲层，由此获得了体声波谐振结构404和第一衬底400之间的第一空腔402，第一空腔402是凸设在第一衬底400上的。至此，完成了步骤S1中提供谐振腔主体结构40的工艺过程。
此外，需要说明的是，当第一衬底400为晶圆时，第一衬底400上的体声波谐振结构404的数量并不仅仅限定于一个，也就是说，可以在第一衬底400上同时形成有多个体声波谐振结构404，每个体声波谐振结构404和第一衬底400之间都具有一个第一空腔402，相邻第一空腔402之间可以通过下腔体壁401隔开，相邻的体声波谐振结构404之间可以是相互断开的，或者有部分膜层是连接在一起的。
请参考图3B和3C，在步骤S2中，首先，提供第二衬底300，所述第二衬底300可以为包括硅基底的衬底，例如为体硅衬底、绝缘体上硅衬底或者由硅基底及层叠在硅基底上的二氧化硅层组成的衬底(此时该二氧化硅层面向体声波谐振结构设置)，以在后续能够采用硅穿孔(TSV)工艺形成穿通孔。然后，在所述第二衬底300上覆盖具有弹性的弹性键合材料层301，弹性键合材料层 301所选用的材料需要满足：能图形化、能在一定的条件下固化、能稳定地与上下层的材料粘附且具有弹性以能够在后续键合晶圆时容忍一定的台阶高度差异，因此，所述弹性键合材料层301的材料可以为光固化材料、热固化材料或者光固化材料和热固化材料的组合，能通过光照、加热后冷却的方式失去弹性，例如为干膜。可选地，可以通过涂覆工艺(例如旋涂、喷涂、滚涂或丝网印刷)涂覆流动性干膜光阻材料或者通过压膜机压合固态或半固态的干膜材料于所述第二衬底300上，以形成弹性键合材料层301。例如，使用压膜机，在80℃～120℃(例如110℃)下且在抽取真空的状态下，将固体干膜材料贴附于所述第二衬底300上而形成弹性键合材料层301。弹性键合材料层301可以是三层结构，例如，一层是PE保护层，中间是干膜层，另一层是PET保护层。PE保护层是以特殊聚乙烯(PE)塑料薄膜为基材的膜层，例如高密度聚乙烯保护膜、中密度聚乙烯和低密度聚乙烯。PET保护层全称是聚对苯二甲酸乙二酯，它是由对苯二甲酸与乙二醇缩合聚合反应而得的。PE保护层和PET层都只是起保护作用，在压膜前和显影前都会去掉的，因此最终夹在第二衬底300和第一衬底400之间的是中间一层干膜层，它具有一定的粘性和良好的感光性，弹性键合材料层301的厚度为10μm～20μm。
接着，通过包括曝光、显影在内的一系列光刻工艺，图形化所述弹性键合材料层301以形成第二空腔302。具体地，首先，在所述弹性键合材料层301上形成掩膜，真空条件下进行紫外线曝光，曝光后静置片刻，所述紫外线曝光的辐照剂量例如为200J/cm2～300mJ/cm2；接着，在100℃～150℃(例如130℃)的温度下，对曝光后的所述弹性键合材料层301预烘烤100秒～300秒(例如200秒)；然后，在常温下，多次(例如3次)在预烘烤后的所述弹性键合材料层301旋喷显影液，来对预烘烤后的所述弹性键合材料层301显影，以形成具有第二空腔302的弹性键合材料层301，所述显影液为PGMEA，其成分包括丙二醇甲醚醋酸酯，丙二醇甲醚醋酸酯的分子式为C6H12O3。至此，完成了谐振器盖体30的制作。其中第二空腔302的形状和尺寸可以均与第一空腔402相同，也可以不完全相同，只要第二空腔302能够使得在后续键合后，体声波谐振结构404的第一电极层4041、压电层4042以及第二电极层4042具有与第一空腔402和第二空腔302同时重叠的部分即可，由此形成谐振器的有效谐振区。
请参考图3C，在步骤S3中，将所述第二空腔302的开口朝向所述体声波 谐振结构404放置并与第一空腔402对准，且通过所述弹性键合材料层301将所述第二衬底300和所述体声波谐振结构404以及下腔体壁401键合在一起。其中，体声波谐振结构404在所述第一空腔402外围的区域中具有暴露出部分或全部的第一电极4041(即第一电连接部)的开口404’，所述开口404’使得所述体声波谐振结构404具有高度为H的台阶，后续的第一穿通孔将形成在开口404’的区域中，因此，本实施例中，通过用力压合的方式将所述第二衬底300和所述谐振腔主体结构40键合在一起(即第二衬底300通过弹性键合材料层301与体声波谐振结构404及其暴露出的下腔体壁401键合在一起)，所述弹性键合材料层301的厚度能适应性地随所述开口404’处的台阶而变化，并同时使得所述第二衬底300和第一衬底400相互背对的表面均保持水平。此时，所述弹性键合材料层301因其本身具有的弹性而适应阶高度差异变化为两部分：一部分粘接到被开口404’暴露出的第一电极4041和对准标记403的表面上而形成高度较大的第一上腔体壁3011，另一部分粘接到第一空腔402外围的与第一上腔壁3011相对的第二电极4043的表面上，形成高度较小的第二上腔体壁3012，第一上腔体壁3011和第二上腔体壁3012面向第一衬底400的一面的高度差为H，第一上腔体壁3011和第二上腔体壁3012面向第二衬底300的一面齐平或接近齐平，所述第二衬底300和所述第一衬底400通过第一上腔体壁3011和第二上腔体壁3012的粘性以及分子结合力键合在一起。这种键合工艺简单，不会影响第一空腔402和第二空腔302的性能，且能容忍第一衬底400上的体声波谐振结构404在第一空腔402外围的区域上具有一定的台阶高度差异，由此使得在所述第二衬底300和所述第一衬底400键合在一起后，避免台阶高度差异引起第二衬底背向第一衬底的一面发生倾斜的问题以及避免因台阶高度差异而引起键合不可靠的问题。可选地，键合谐振器盖体30和谐振腔主体结构40的工艺条件包括：键合压力为1Pa～105Pa，真空键合，温度为150℃～200℃(例如为150℃)，施压时间为20min～30min，由此在保证键合性能的前提下，避免影响产品的谐振性能。在键合完以后通过光照、加热后冷却的方式固化弹性键合材料层301，即使得弹性键合材料层301失去弹性，以使得谐振器盖体30和谐振腔主体结构40可靠的连接在一起。固化弹性键合材料层301的工艺可以选用高温固化工艺，其固化温度为180℃～220℃(例如为190℃)，固化时间为1.5小时～2小时(例如为2小时)。在本发明的其他实施例中，固化弹性键合材料层 301的工艺也可以选择紫外光固化工艺，紫外线固化的辐照剂量可选为200mJ/cm2～300mJ/cm2，与图形化弹性键合材料层301时的紫外线曝光工艺所使用的光照相同，以简化工艺，降低成本。
请参考图3D和3E，在步骤S4中，首先，请参考图3D，通过化学机械研磨(CMP)工艺，从所述第二衬底300背向所述体声波谐振结构404的一面进行减薄，例如将第二衬底300的厚度减薄至60μm～80μm。然后，采用硅穿孔(TSV)刻蚀工艺，从第一上腔体壁3011处的所述第二衬底300背向所述体声波谐振结构404的一侧开孔至穿通第一上腔体壁3011而暴露出开口404’处的部分第一电极4041，形成第一穿通孔3031，从第二上腔体壁3012处的所述第二衬底300背向所述体声波谐振结构404的一侧开孔至穿通第二上腔体壁3012而暴露部分第二电极4043，形成第二穿通孔3032，其中，被第一穿通孔3031暴露出的伸出第一空腔402的部分第一电极4041，称为第一电连接部，被第二穿通孔3032暴露出的伸出第一空腔402的部分第二电极4043，称为第二电连接部。具体的，可以通过曝光、显影和刻蚀工艺，依次刻蚀第一上腔体壁3011处的所述第二衬底300以及第一上腔体壁3011而形成第一穿通孔3031，形成第一穿通孔3031的刻蚀过程直至露出第一电极4041为止；然后再通过曝光、显影和刻蚀工艺刻蚀第二上腔体壁3012处的所述第二衬底300以及第二上腔体壁3012而形成第二穿通孔3032，第二穿通孔3032的刻蚀过程直至露出第二电极4043为止，当然在本发明的其他实施例中，也可以先形成第二穿通孔3032再形成第一穿通孔3031。第一穿通孔3031和第二穿通孔3032的尺寸可以根据需要暴露的电极范围以及刻蚀条件确定。本实施例中，第一穿通孔3031和第二穿通孔3032的开口直径约20μm～70μm，第一穿通孔3031和第二穿通孔3032的深度约60μm～100μm。
请参考图3E，在步骤S5中，首先，可以采用包括溅射、等离子体物理气相沉积、高密度等离子体化学气相沉积、低压化学气相沉积、原子层沉积等沉积扩散阻挡层304，由于采用沉积工艺形成扩散阻挡层304，所以扩散阻挡层304不仅形成在第一穿通孔3031和第二穿通孔3032的内表面上，还覆盖在第二衬底300背向体声波谐振结构404的一面上，该扩散阻挡层304可选为叠层结构，包括用于使得后续形成的导电互连层305与第二衬底300电学绝缘隔离的氮化物层(未图示)以及层叠在该氮化物层表面上的阻挡粘附层(未图示)，该阻挡 粘附层的材料包括Al、Au、Cr、Co、Ni、Cu、Mo、Ti、Ta、W、Pt等中的至少一种。其中等离子体物理气相沉积、高密度等离子体化学气相沉积、低压化学气相沉积、原子层沉积工艺具有较佳的台阶覆盖能力，可以避免形成的扩散阻挡层304填充满所述第一穿通孔3031和第二穿通孔3032。然后刻蚀去除第一穿通孔3031和第二穿通孔3032底部的扩散阻挡层304，以暴露出第一穿通孔3031和第二穿通孔3032底壁上的第一电极4041和第二电极4043，此时，第一穿通孔3031和第二穿通孔3032周围的第二衬底300的表面上仍覆盖有扩散阻挡层，以实现后续第一穿通孔3031和第二穿通孔3032中的导电互连层之间的电性绝缘隔离。
请继续参考图3E，在步骤S5中，接着，可以采用包括溅射、电镀、等离子体物理气相沉积、高密度等离子体化学气相沉积、低压化学气相沉积、原子层沉积等工艺进行通孔金属化，以形成导电互连层305，此时，导电互连层305覆盖在扩散阻挡层304及其暴露出的第一穿通孔3031和第二穿通孔3032的底壁上，所述导电互连层305的材料可以与第二电极和第一电极的材料相同，沉积工艺条件和后续的刻蚀工艺条件也相同，由此能最大程度的兼容步骤S1的工艺，并简化工艺。此外在本发明的其他实施例中，所述导电互连层305的材料可以是包括Ti、Ta、W、Mo、Cu、W等中的至少一种。然后通过曝光、显影和刻蚀工艺去除第二衬底300背向第一衬底400的表面上的部分导电互连层305，以图形化导电互连层305，形成的图形化的导电互连层305分别电连接第二电极4043和第一电极4042。
需要说明的是，由于本实施例中，采用干膜作为弹性键合材料层，而干膜材料在在温度和湿度变化的情况下，其性能不够稳定，因此为了避免干膜材料的温湿度漂移而导致第二空腔302的性能以及谐振器盖体30和谐振腔主体结构40的键合性能发生变化，请参考图4，在本发明另一实施例的步骤S5中，在形成扩散阻挡层304之前，先通过材料沉积和刻蚀工艺在第一穿通孔3031和第二穿通孔3032的侧壁上形成内侧墙308，所述内侧墙308的材质不同于所述弹性键合材料层301并用于补偿所述弹性键合材料层301的温湿度漂移。所述内侧墙308的材质例如为二氧化硅、氮化硅、氮氧化硅或TEOS(正硅酸乙酯)。所述内侧墙308可以保持弹性键合材料层303的最终高度，阻止弹性键合材料层301的温湿度漂移影响第二空腔302的性能以及谐振器盖体30和谐振腔主体结 构40的键合的稳定性和可靠性。
请参考图3E和图4，在步骤S6中，首先，可以采用包括溅射、电镀、等离子体物理气相沉积、高密度等离子体化学气相沉积、低压化学气相沉积、原子层沉积等工艺，在第一穿通孔3031和第二穿通孔3032中以及第二衬底300背向所述第一衬底400的表面上的导电互连层305和第二衬底300被导电互连层305暴露出的表面上沉积钝化层306，沉积的钝化层306的厚度足以填满第一穿通孔3031和第二穿通孔3032，其中，钝化层306的材质可以与压电层4042的材质相同，并采用与压电层4042完全相同的沉积工艺，由此最大限度兼容谐振腔主体结构40的工艺，同时还能避免使用其他材料来制作钝化层时引起的温度漂移的问题以及引入不必要的应力的问题，由此提高谐振器的谐振性能。接着，通过曝光、显影、刻蚀工艺图形化钝化层306，以形成接触开口307，其中，图形化钝化层306的工艺条件可以与图形化压电层402的工艺条件完全相同，由此最大限度兼容谐振腔主体结构40的工艺，该接触开口307能够暴露出第二衬底300背向所述第一衬底400的表面上的部分导电互连层306，以形成导电接触垫(pad)3051，该导电接触垫3051包括与第一电极4041电性连接的导电接触垫和与第二电极4043电性连接的导电接触垫。此时，钝化层306还填满第一穿通孔3031和第二穿通孔3032，以增强上腔体壁301的机械支撑性能。
需要说明的是，在本发明的其他实施例中，上述步骤S1和S2也可以同时执行，或者先执行步骤S2后执行步骤S1。此外，在本发明的其他实施例中，也可以采用常规的钝化材料来形成钝化层306，这些常规的钝化材料包括氧化硅、氮化硅、氮氧化硅、金属氮化物和聚合物中的至少一种。
综上所述，本发明的体声波谐振器的封装方法，不仅具有低成本、工艺简单以及跟谐振腔主体结构的工艺高度相容的特点，还不会造成金-金键合工艺的污染问题。且能容忍体声波谐振结构在第一空腔外围的区域上具有一定的台阶高度差异，保证键合的可靠性和稳定性。此外，由于谐振器盖体上所需的主要结构均是在第二衬底上完成的，因此能最大限度地降低了对第一空腔的影响。
请参考图3E和图4，本发明一实施例还提供一种采用本发明的体声波谐振器的封装方法制作而成的体声波谐振器的封装结构。所述体声波谐振器的封装结构包括谐振腔主体结构40和谐振器盖体30，所述谐振腔主体结构40包括第一衬底400、体声波谐振结构404以及第一腔体402，所述谐振器盖体包括第二 衬底300、失去弹性的弹性键合材料层301、第二空腔302、第一穿通孔3031和第二穿通孔3032、导电互连层305以及图形化的钝化层306。其中，体声波谐振结构404形成在所述第一衬底400上，第一空腔402夹在体声波谐振结构404和第一衬底400之间。第二衬底300设置在体声波谐振结构404的上方，所述弹性键合材料层301夹在所述第二衬底300和所述体声波谐振结构404之间，第二空腔302形成在所述弹性键合材料层301中并被夹设在所述第二衬底300和所述体声波谐振结构404之间，所述第二空腔302与所述第一空腔402至少有部分对准。所述第一穿通孔3031和第二穿通孔3032均位于所述第一空腔402和所述第二空腔302的外围，且均穿过谐振器盖体40，并暴露出所述体声波谐振结构404相应的电连接部。导电互连层305覆盖第一穿通孔3031和第二穿通孔3032的内表面(包括侧壁和底壁)，并分别从第一穿通孔3031和第二穿通孔3032的侧壁上连续延伸到所述第二衬底300背向所述体声波谐振结构404的部分表面上，即所述导电互连层305形成于第一穿通孔3031和第二穿通孔3032的内表面以及所述第一穿通孔3031和第二穿通孔3032外围的部分所述谐振器盖体的表面上。图形化的钝化层306填满所述第一穿通孔3031和第二穿通孔3032中并覆盖所述第二衬底300背向所述体声波谐振结构404的表面上的部分所述导电互连层305，且被图形化的钝化层306暴露出的所述导电互连层305形成相应的导电接触垫。
本实施例中，所述体声波谐振结构404具有依次层叠在所述第一衬底400上的第一电极4041、压电层4042和第二电极4043，且第一空腔402形成在所述第一衬底400和所述第一电极4041之间，该第一空腔402通过下腔体壁401围成。本实施例中，所述下腔体壁401是不同于第一衬底400和体声波谐振结构404的材料的支撑层(即3E和图4中的第一下腔体壁层4011至第三下腔体壁层4013)，所述第一衬底400和所述体声波谐振结构400之间通过该支撑层键合在一起，所述第一空腔402形成在所述支撑层中，弹性键合材料层301形成在第一空腔402外围的支撑层上。在本发明的其他实施例中，所述第一空腔402可以是整个底部凹陷在所述第一衬底400中的凹槽结构，此时，下腔体壁401为凹槽周围的第一衬底400；或者，所述第一空腔402为整体上凸设在所述第一衬底400表面上的腔体结构，这两种情况下，弹性键合材料层302形成在第一空腔402外围的第一衬底400上。
由于本实施例的所述体声波谐振结构404包括第一电极4041和第二电极4043，所以本实施例中，所述第一穿通孔402从所述第二衬底300背向所述体声波谐振结构404的表面穿通至暴露出部分第一电极4041的表面，所述第二穿通孔3032从所述第二衬底300背向所述体声波谐振结构404的表面穿通至暴露出部分所述第二电极4043的表面。也就是说，本实施例中，体声波谐振结构404的电连接部包括：第一电连接部，包括伸出第一空腔的部分第一电极4041；第二电连接部，包括伸出第一空腔的部分第二电极4043。
本实施例中，覆盖所述第二衬底300背向所述体声波谐振结构404的表面上的图形化的钝化层306具有接触开口307，接触开口307暴露出相应区域的所述导电互连层305，所述导电互连层305被接触开口307暴露的部分形成导电接触垫3051，导电互连层305分别电连接第二电极4043和第一电极4041，以用于分别将第二电极4043和第一电极4041通过相应的导电接触垫3051向外引出。
本实施例中，第二衬底300包括硅基底，例如裸硅衬底，由此使得第一穿通孔3031和第二穿通孔3032可以通过硅穿孔工艺制作。
本实施例中，弹性键合材料层301所选用的材料需要满足：能图形化、能在一定的条件下固化、能稳定地与上下层的材料粘附且具有弹性以能够在后续键合晶圆时容忍一定的台阶高度差异，因此，所述弹性键合材料层301的材料可以为光固化材料、热固化材料或者光固化材料和热固化材料的组合，能通过光照、加热后冷却的方式失去弹性，例如为干膜。
本实施例中，所述体声波谐振结构404在所述第一空腔402外围的部分中具有暴露部分所述第一电极4041的开口404’，开口404’的形状为闭合的环形或半环形等，体声波谐振结构404在开口404’处形成的台阶的高度均匀，均为H；所述第二衬底300和所述第一衬底400之间的所述弹性键合材料层301的厚度能适应所述体声波谐振结构404的台阶高度而变化，并同时能维持所述第二衬底300和第一衬底400相互背向的表面水平，以利于形成的体声波谐振器产品与其他产品集成在同一个印刷电路板上。
此外，在本发明的一些实施例中，所述第一穿通孔3031和第二穿通孔3032的侧壁上形成有内侧墙308，所述内侧墙308夹设在所述弹性键合材料层301和所述导电互连层305之间，且所述内侧墙308的材质不同于所述弹性键合材料层301并用于补偿所述弹性键合材料层301的温湿度漂移，以保证第二空腔的 稳定性以及第二衬底和第一衬底键合的稳定性。
此外，在本发明的一些实施例中，所述钝化层306和所述压电层4042的材质相同，沉积工艺和刻蚀工艺也相同，以最大限度兼容第一空腔工艺，同时还能避免使用其他材料来制作钝化层时引起的温度漂移的问题以及引入不必要的应力的问题，由此提高谐振器的谐振性能。当然，在本发明的另外一些实施例中，也可以采用常规的钝化材料来形成钝化层306，这些常规的钝化材料包括氧化硅、氮化硅、氮氧化硅、金属氮化物和聚合物中的至少一种。
此外，本实施例中，所述第一衬底400和所述第一电极4041之间用于围出所述第一空腔402的下腔体壁401中还形成有对准标记403，所述对准标记403穿通所述体声波谐振结构404而与所述弹性键合材料层301键合在一起。
需要说明的是，由于本实施例的体声波谐振器的封装结构采用本发明的体声波谐振器的封装方法制作，因此，其中各个结构的材质、尺寸等参数均可以参考上文的体声波谐振器的封装方法中的内容，在此不再赘述。
本发明的体声波谐振器的封装结构，能够改善谐振器的谐振性能，且可以采用本发明的体声波谐振器的封装方法制作，以简化工艺，降低成本。
显然，本领域的技术人员可以对发明进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (20)

  1. 一种体声波谐振器的封装方法，其特征在于，包括以下步骤：
    提供谐振腔主体结构，所述谐振腔主体结构包括第一衬底以及形成在所述第一衬底上的体声波谐振结构，所述第一衬底和所述体声波谐振结构之间形成有第一空腔；
    提供第二衬底，在所述第二衬底上形成具有第二空腔的弹性键合材料层，以形成谐振器盖体；
    通过所述弹性键合材料层将所述谐振腔主体结构和所述谐振器盖体键合在一起并使得所述弹性键合材料层失去弹性，且键合后，所述体声波谐振结构夹在所述第一衬底和所述第二衬底之间，所述第二空腔和所述第一空腔至少部分对准；
    形成穿过所述谐振器盖体并暴露出所述体声波谐振结构的相应的电连接部的穿通孔；以及，
    形成导电互连层于所述穿通孔的表面以及所述穿通孔外围的部分所述谐振器盖体的表面上。
  2. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，所述体声波谐振结构包括靠近所述第一衬底的第一电极、位于所述第一电极上的压电层以及位于所述压电层上的第二电极。
  3. 如权利要求2所述的体声波谐振器的封装方法，其特征在于，所述电连接部包括：第一电连接部，包括伸出第一空腔的部分第一电极；第二电连接部，包括伸出第一空腔的部分第二电极。
  4. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，所述体声波谐振结构在所述第一空腔外围的部分中具有暴露部分或全部的所述电连接部的开口；在所述谐振腔主体结构和所述谐振器盖体键合在一起时，所述弹性键合材料层的厚度能适应所述开口处的台阶高度而变化。
  5. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，所述弹性键合材料层的材料为光固化材料和/或热固化材料，能通过光照或加热后冷却的方式失去弹性。
  6. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，所述弹性 键合材料层为干膜。
  7. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，将所述谐振腔主体结构和所述谐振器盖体键合在一起之后且在形成所述穿通孔之前，先对所述第二衬底进行减薄。
  8. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，在形成所述导电互连层于所述穿通孔中之前，先在所述穿通孔的侧壁上形成内侧墙，所述内侧墙的材质不同于所述弹性键合材料层并用于补偿所述弹性键合材料层的温湿度漂移。
  9. 如权利要求2所述的体声波谐振器的封装方法，其特征在于，在形成所述导电互连层之后，还包括：形成图形化的钝化层，所述图形化的钝化层填满所述穿通孔并暴露出所述穿通孔外围的谐振器盖体表面上的部分所述导电互连层，被暴露出的部分所述导电互连层形成导电接触垫。
  10. 如权利要求9所述的体声波谐振器的封装方法，其特征在于，所述钝化层和所述压电层的材质相同；或者，所述钝化层包括氧化硅、氮化硅、氮氧化硅、金属氮化物和聚合物中的至少一种材质。
  11. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，提供所述谐振腔主体结构的步骤包括：
    提供载体衬底，并依次形成用于制作体声波谐振结构的膜层和支撑层于所述载体衬底上；
    刻蚀所述支撑层，以在所述支撑层中形成空腔；
    提供所述第一衬底，并将所述第一衬底键合到所述支撑层上；以及，
    去除所述载体衬底，以形成所述谐振腔主体结构。
  12. 如权利要求11所述的体声波谐振器的封装方法，其特征在于，在用于制作体声波谐振结构的膜层上形成所述支撑层之前，或者，在去除所述载体衬底之后，将所述用于制作体声波谐振结构的膜层图形化，以形成所述体声波谐振结构。
  13. 如权利要求1所述的体声波谐振器的封装方法，其特征在于，提供所述谐振腔主体结构的步骤包括：
    提供第一衬底，形成牺牲层于部分所述第一衬底上；
    形成体声波谐振结构于所述牺牲层和所述第一衬底上；以及，
    去除所述牺牲层，以形成所述第一空腔。
  14. 如权利要求13所述的体声波谐振器的封装方法，其特征在于，形成牺牲层于部分所述第一衬底上的步骤包括：刻蚀所述第一衬底，以形成凹槽于所述第一衬底中；形成所述牺牲层填充于所述凹槽中；或者，
    形成牺牲层于部分所述第一衬底上的步骤包括：覆盖牺牲层于所述第一衬底上；图案化所述牺牲层，以形成牺牲层凸设于部分衬底上。
  15. 一种体声波谐振器的封装结构，其特征在于，包括：
    谐振腔主体结构，所述谐振腔主体结构包括第一衬底以及形成在所述第一衬底上的体声波谐振结构，所述第一衬底和所述体声波谐振结构之间形成有第一空腔；
    谐振器盖体，所述谐振器盖体包括第二衬底以及失去弹性的弹性键合材料层，所述弹性键合材料层夹在所述第二衬底和所述体声波谐振结构之间，所述弹性键合材料层中形成有第二空腔，所述第二空腔与所述第一空腔至少有部分对准，所述谐振器盖体上还设有穿通孔，所述穿通孔穿过所述第二空腔外围的谐振器盖体，并暴露出所述体声波谐振结构相应的电连接部；以及，
    导电互连层，所述导电互连层形成于所述穿通孔的表面以及所述穿通孔外围的部分所述谐振器盖体的表面上。
  16. 如权利要求15所述的体声波谐振器的封装结构，其特征在于，所述体声波谐振结构包括靠近所述第一衬底的第一电极、位于所述第一电极上的压电层以及位于所述压电层上的第二电极；所述电连接部包括：第一电连接部，包括伸出第一空腔的部分第一电极；第二电连接部，包括伸出第一空腔的部分第二电极。
  17. 如权利要求15所述的体声波谐振器的封装结构，其特征在于，所述体声波谐振结构在所述第一空腔外围的部分中具有暴露部分或全部的所述电连接部的开口；在所述谐振器盖体和所述谐振腔主体结构键合在一起时，所述弹性键合材料层的厚度能适应所述开口处的台阶高度而变化。
  18. 如权利要求15所述的体声波谐振器的封装结构，其特征在于，所述弹性键合材料层的材料为光固化材料和/或热固化材料，能通过光照或加热后冷却的方式失去弹性。
  19. 如权利要求16所述的体声波谐振器的封装结构，其特征在于，所述封 装结构还包括内侧墙和/或图形化的钝化层，所述内侧墙位于所述穿通孔的侧壁上，并夹设在所述弹性键合材料层和所述导电互连层之间，且所述内侧墙的材质不同于所述弹性键合材料层并用于补偿所述弹性键合材料层的温湿度漂移；所述图形化的钝化层填满所述穿通孔并暴露出所述穿通孔外围的谐振器盖体表面上的部分所述导电互连层，被暴露出的部分所述导电互连层形成导电接触垫。
  20. 如权利要求19所述的体声波谐振器的封装结构，其特征在于，所述钝化层和所述压电层的材质相同；或者，所述钝化层包括氧化硅、氮化硅、氮氧化硅、金属氮化物和聚合物中的至少一种材质。
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