WO2023016500A1 - Bulk acoustic resonator having two piezoelectric layers, filter, and electronic device - Google Patents

Bulk acoustic resonator having two piezoelectric layers, filter, and electronic device Download PDF

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Publication number
WO2023016500A1
WO2023016500A1 PCT/CN2022/111528 CN2022111528W WO2023016500A1 WO 2023016500 A1 WO2023016500 A1 WO 2023016500A1 CN 2022111528 W CN2022111528 W CN 2022111528W WO 2023016500 A1 WO2023016500 A1 WO 2023016500A1
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layer
resonator
electrode
acoustic impedance
piezoelectric layer
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PCT/CN2022/111528
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French (fr)
Chinese (zh)
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徐洋
庞慰
郝龙
黄源清
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诺思(天津)微系统有限责任公司
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Publication of WO2023016500A1 publication Critical patent/WO2023016500A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material

Definitions

  • Embodiments of the present invention relate to the field of semiconductors, and in particular to a bulk acoustic wave resonator and a manufacturing method thereof, a filter with the resonator, and an electronic device.
  • FBAR Film Bulk Acoustic Resonator
  • BAW Bulk Acoustic Resonator
  • SAW surface acoustic wave
  • the structural body of the film bulk acoustic resonator is a "sandwich" structure composed of electrodes-piezoelectric film-electrodes, that is, a layer of piezoelectric material is sandwiched between two layers of metal electrode layers.
  • FBAR uses the inverse piezoelectric effect to convert the input electrical signal into a mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output.
  • a currently known method for increasing the parallel impedance of a BAW resonator is to add an air layer or a dielectric layer between the piezoelectric layer and the top electrode.
  • 1 shows a schematic cross-sectional view of a known BAW resonator, which includes a substrate 101, an acoustic mirror 102, a bottom electrode layer 103, a piezoelectric layer 104, an air layer or dielectric layer 105, a top electrode 106, a blunt layer or process layer 107.
  • a bulk acoustic wave resonator including a substrate, a bottom electrode, an acoustic mirror, a top electrode and a piezoelectric layer.
  • the bottom electrode includes at least a first electrode layer and a second electrode layer disposed in a thickness direction of the resonator.
  • a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines an acoustic mirror of the resonator.
  • the piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is formed with a cantilever along the effective area of the resonator structure.
  • a first acoustic impedance mismatch structure is defined between the lower surface of the suspension wing structure and the upper surface of the first piezoelectric layer.
  • a method for manufacturing the above-mentioned bulk acoustic wave resonator including: step 1: forming a bottom electrode and a first piezoelectric layer covering the bottom electrode, the bottom electrode includes at least A first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines an acoustic mirror of the resonator; step 2: Forming a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer is at least used to form a first acoustic impedance mismatch structure; Step 3: forming a patterned second piezoelectric layer, the second piezoelectric The middle part of the layer covers the upper surface of the first piezoelectric layer, and the edge part covers the upper surface of the patterned dielectric layer to form a cantilever structure; and step 4: covering the structure formed in step 3 with
  • Embodiments of the present invention also relate to a filter, including the above bulk acoustic wave resonator.
  • Embodiments of the present invention also relate to an electronic device, including the above-mentioned filter or the above-mentioned resonator.
  • Fig. 1 is a schematic cross-sectional view of a known bulk acoustic wave resonator
  • FIG. 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention
  • FIG. 2B is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • Fig. 3 is a comparison diagram of the parallel impedance of the resonator shown in Fig. 1 and the resonator shown in Fig. 2A;
  • FIGS. 4-7 are schematic cross-sectional views of bulk acoustic wave resonators according to different exemplary embodiments of the present invention.
  • FIG. 8-11 are schematic cross-sectional views schematically showing the manufacturing process of the bulk acoustic wave resonator in FIG. 2 according to an exemplary embodiment of the present invention.
  • the present invention proposes a bulk acoustic wave resonator structure with double piezoelectric layers, wherein the upper piezoelectric layer forms a cantilevered structure at the edge of the active area of the resonator, the cantilevered structure defines an acoustic impedance mismatch structure, thereby It is beneficial to increase the parallel impedance of the resonator, thereby improving the performance of the resonator.
  • the optional material is single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
  • Acoustic mirror which can be a cavity, for example, Bragg reflection layer and other equivalent forms can also be used.
  • the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or alloys thereof.
  • the first piezoelectric layer, the material can be aluminum nitride, gallium nitride, lithium niobate, lead zirconate titanate (PZT), potassium niobate, quartz film, zinc oxide, etc., or certain atoms containing the above materials
  • the ratio of rare earth element doping materials, such as doped aluminum nitride, doped aluminum nitride contains at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), Lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (L
  • the second piezoelectric layer the material of which can be the same as that of the first piezoelectric layer 104.
  • the material can be air, SiO 2 , SiN, etc.
  • the first acoustic impedance mismatch structure The first acoustic impedance mismatch structure.
  • the second acoustic impedance mismatch structure The second acoustic impedance mismatch structure.
  • the top electrode the material of which can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or alloys thereof.
  • the top and bottom electrodes are typically of the same material, but can also be different.
  • a dielectric layer or a process layer the material of which is generally a dielectric material, such as aluminum nitride, silicon dioxide, silicon nitride, etc. As can be understood, no dielectric layer or process layer may be provided.
  • a seed layer or a barrier layer the material of which may be AlN, SiN or the like. As can be understood, the seed layer or barrier layer 112 may also not be provided.
  • the bottom electrode layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or their alloys, etc., the bottom electrode layer 103 and the bottom electrode layer 113 Materials can vary. as can be understood.
  • the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the metals above or their alloys, etc., and the protruding structure may not be provided.
  • the material can be AlN, SiN, SiO 2 and so on.
  • the concave structure forming layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the above metals or their alloys.
  • the material may be AlN, SiN, SiO 2 and so on.
  • FIG. 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.
  • the BAW resonator includes: a substrate 101; an acoustic mirror 102, which is in the form of a cavity or a void layer in Figure 2; a bottom electrode, including a bottom electrode layer 103 and a bottom electrode layer 113, and the acoustic mirror 102 between the bottom electrode layer 103 and the bottom electrode layer 113; the top electrode 106; and the first piezoelectric layer 104 and the second piezoelectric layer 104'.
  • the second piezoelectric layer 104' is on the upper side of the first piezoelectric layer 104, and the end of the second piezoelectric layer 104' is formed with a cantilever structure along at least a part of the effective area of the resonator,
  • An acoustic impedance mismatch structure 105A is defined between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer 104.
  • the acoustic impedance mismatch structure 105A is made of air, it can be seen that along the resonator In the effective area of , the air layer is set between the two piezoelectric layers.
  • the resonator is also provided with an acoustic impedance mismatch structure 105B, and the acoustic impedance mismatch structures 105A and 105B are connected to each other in the horizontal direction. That is, the resonator shown in FIG. 2A is formed with a bridge structure, an acoustic impedance mismatching structure 105B is formed between the lower surface of the bridge structure and the upper surface of the first piezoelectric layer 104, and the acoustic impedance mismatching structure 105A and the acoustic impedance The mismatched structures 105B are in contact with each other.
  • Fig. 3 is a comparison diagram of the parallel impedance of the resonator shown in Fig. 1 and the resonator shown in Fig. 2A, wherein the resonator parallel impedance shown in Fig. 1 is defined as 1, then the parallel impedance of the resonator shown in Fig. 2A is 1.4, which means that the parallel impedance of the resonator shown in FIG. 2A is 40% higher than that of the resonator in FIG. 1 .
  • a bridge structure is also provided at the electrode connection end of the top electrode so that the resonator also forms an acoustic impedance mismatch structure 105B, but the present invention is not limited thereto. In other words, only the electrode connection end of the top electrode can be reserved. At least a part of the acoustic impedance mismatching structure 105A outside, so that the acoustic impedance mismatching structure 105B is not provided, and the piezoelectric layer at the electrode connection end of the top electrode is not provided with a cantilever structure. Such a resonance is shown in FIG. 2B device structure.
  • the upper surface of the first piezoelectric layer 104 defines a junction between the acoustic impedance mismatch structure 105A and the acoustic impedance mismatch structure 105B.
  • the lower surface of the part is flush with the upper surface of the part where the acoustic impedance mismatching structure 105A and the acoustic impedance mismatching structure 105B meet.
  • the resonator further includes a dielectric layer or process layer 107 , as mentioned above, the dielectric layer or process layer 107 may not be provided.
  • the bottom electrode can be not only two layers of electrodes, but also more electrode layers. In the case that the bottom electrode adopts double-layer electrodes or more electrodes, it is beneficial to reduce the resistance loss of the electrodes, thereby reducing the series impedance of the resonator.
  • the filter manufactured by using the resonator of the present invention can increase the insertion loss of the overall passband.
  • the acoustic impedance mismatch structure 105A can be arranged along the entire effective area of the resonator, or only along a part of the area, all within the protection scope of the present invention.
  • the inner boundary of the acoustic impedance mismatch structure 105A is inboard of the boundary of the acoustic mirror 102 , thereby defining the boundary of the active area of the resonator.
  • the inner boundary of the acoustic impedance mismatch structure 105A may only define a part of the boundary of the effective area or not define the boundary of the effective area, and these are also within the protection scope of the present invention.
  • the bottom electrode is a multilayer electrode and the gap layer is sandwiched between the electrode layers to form an acoustic mirror. At this time, the resistance loss of the bottom electrode can be reduced to reduce the series impedance of the resonator.
  • the resonator is also provided with a barrier or seed layer 112 .
  • the barrier layer 112 can protect the bottom electrode 103 when releasing or etching the later-mentioned sacrificial layer for the acoustic mirror.
  • the barrier or seed layer 112 may also be omitted.
  • a step portion may also be provided in the structure shown in FIG. 2A .
  • Such a resonator structure is shown in FIG. 4 .
  • a stepped portion is added at the position marked by a circle, thereby further increasing the number of impedance mismatch boundaries and further limiting the shear wave leakage of the resonator.
  • the lower surface of the bridge structure defining the upper surface of the acoustic impedance mismatching structure 105B is provided with an upper step portion A (circle A is shown in FIG. 4 ), and the lower surface defining the lower surface of the acoustic impedance mismatching structure 105B
  • the upper surface of the first piezoelectric layer 104 is provided with a lower step portion B (a circle B is shown in FIG. 4 ).
  • the bridge structure is directly formed by the electrode connection end of the top electrode of the resonator, specifically, the lower surface of the bridge structure is the lower surface of the electrode connection end of the top electrode.
  • the bridge structure may also include a protruding structure. In this case, an upper step portion A may be provided on the lower surface of the protruding structure.
  • the upper stepped portion is formed on the lower surface of the bridge structure, while the lower stepped portion is disposed on the upper surface of the first piezoelectric layer 104 .
  • the upper step portion or the lower step portion may be provided, and of course both the upper step portion and the lower step portion may be provided as shown in FIG. 4 .
  • the number of the upper step portion and the lower step portion is not limited.
  • the upper stepped portion A is disposed between the acoustic impedance mismatch structure 105A and the boundary of the acoustic mirror 102 in the horizontal direction.
  • the lower step portion B is arranged outside the non-electrode connection end of the bottom electrode in the horizontal direction.
  • the upper surface of the first piezoelectric layer 104 is provided with another step portion C (shown in FIG. 4 ) outside the boundary of the acoustic mirror 102 . Out of the circle C).
  • the acoustic impedance mismatch structure 105B its upper surface may be directly defined by the lower surface of the electrode connection end of the top electrode, as shown in FIGS. 2A-2B and FIGS. 4-5 .
  • the upper surface of the acoustic impedance mismatch structure 105B may be directly defined by the lower surface of the protruding structure, As shown in FIGS. 6 and 7 mentioned later.
  • the end face of the film layer on the upper side of the second piezoelectric layer 104' is flush with the end face of the second piezoelectric layer 104', but the present invention does not limited to.
  • the end surface of at least one film layer on the upper side of the second piezoelectric layer 104' may also be horizontally staggered from the end surface of the second piezoelectric layer 104', as shown in FIG. 5 An exemplary structure. In FIG.
  • the end faces of the film layers on the upper side of the second piezoelectric layer 104 ′ are all inside the end faces of the second piezoelectric layer 104 ′.
  • the end faces of at least one film layer on the upper side It may also be located outside the end surface of the second piezoelectric layer.
  • the structure shown in FIG. 5 is similar to the structure shown in FIG. 2A except that the end face of the film layer on the second piezoelectric layer at the non-electrode connection end of the top electrode is staggered from the end face of the second piezoelectric layer, and will not be repeated here.
  • a protruding structure may also be added in the resonator, such an exemplary structure is shown in FIG. 6 .
  • the resonator further includes a protruding structure 114 disposed on the lower side of the top electrode 106, and at the electrode connection end of the top electrode, the protruding structure 114 defines the upper surface of the acoustic impedance mismatch structure 105B.
  • the structure shown in FIG. 6 is similar to the structure shown in FIG. 2A except that the protruding structure 114 is additionally provided, and details are not repeated here.
  • the resonator may also be provided with a recessed structure, and such a resonator structure is exemplarily shown in FIG. 7 .
  • a resonator structure is exemplarily shown in FIG. 7 .
  • on the upper side of the top electrode 106 is also provided a recessed structure forming layer 116 for forming a recessed structure at its edge.
  • the structure shown in FIG. 7 is similar to the structure shown in FIG. 6 except that a recess structure is additionally provided, and details are not repeated here.
  • the manufacturing process of the resonator structure shown in FIG. 2A is exemplarily described below with reference to FIGS. 8-11 .
  • a substrate 101 is provided, a metal layer for forming a bottom electrode layer 113 is deposited on the substrate 101, and then the acoustic mirror sacrificial material layer 115 is deposited and patterned on the metal layer (that is, the acoustic mirror is a cavity For example), then deposit and pattern the seed layer 112, then deposit the metal layer for forming the bottom electrode layer 103, and pattern the two metal layers to form the bottom electrode, as shown in FIG. 8 .
  • the material of the bottom electrode layer 103 and the bottom electrode layer 113 may be the same. In a further optional embodiment, the materials of the bottom electrode layer 103 and the bottom electrode layer 113 can be different. It can be that the acoustic impedance of the bottom electrode layer 103 in FIG.
  • the conductivity of the bottom electrode layer 113 is higher than that of the bottom electrode layer 103 .
  • a first piezoelectric layer 104 is deposited.
  • a sacrificial material layer is deposited and patterned on the upper surface of the first piezoelectric layer 104 (here, the acoustic impedance mismatch structure 105 is used as a cavity as an example, but as It can be understood that the acoustic impedance mismatch structure may directly be a dielectric layer without release) to form the acoustic impedance mismatch structure sacrificial layer 118 .
  • a second piezoelectric layer 104' is deposited and patterned to form the structure shown in FIG. 11 .
  • the top electrode 106 and the process layer 107 can be formed by sequential deposition and patterning, and then the acoustic mirror sacrificial material layer 115 can be released to form the acoustic mirror 102, and the acoustic impedance mismatch structure sacrificial layer 118 can be released to form Acoustically impedance-mismatched structures 105A and 105B result in the resonator structure shown in Figure 2A.
  • the protruding structures and/or concave structures disposed along the effective area in the resonator are not limited to the positions shown in FIG. 6 and FIG. 7 , for example.
  • the protrusion structure it may also be disposed in the piezoelectric layer, or disposed between the piezoelectric layer and the bottom electrode, and the like. These are all within the protection scope of the present invention.
  • up and down are relative to the bottom surface of the base of the resonator.
  • the side close to the bottom surface is the bottom side
  • the side away from the bottom surface is the top side.
  • inner and outer are relative to the center of the effective area of the resonator (the overlapping area of the piezoelectric layer, the top electrode, the bottom electrode and the acoustic mirror in the thickness direction of the resonator constitutes the effective area) (i.e. the center of the effective area )
  • the side or end of a component that is close to the center of the effective area is the inner or inner end, while the side or end of the component that is far from the center of the effective area is the outer or outer end.
  • the bulk acoustic wave resonator according to the present invention can be used to form filters or electronic devices.
  • a bulk acoustic wave resonator comprising:
  • the bottom electrode includes at least a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines the resonator acoustic mirrors;
  • the piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is formed along the effective area of the resonator
  • the suspension wing structure, a first acoustic impedance mismatch structure is defined between the lower surface of the suspension wing structure and the upper surface of the first piezoelectric layer.
  • the resonator is formed with a bridge structure, and a bridge structure is formed between the lower surface of the bridge structure and the upper surface of the first piezoelectric layer.
  • a second acoustic impedance mismatch structure is formed between them, and the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure are connected to each other.
  • the upper step portion is disposed between the boundary of the first acoustic impedance mismatching structure and the acoustic mirror in the horizontal direction;
  • the lower step portion is disposed outside the non-electrode connection end of the bottom electrode in the horizontal direction.
  • the upper surface of the second acoustic impedance mismatching structure is defined by the electrode connection end of the top electrode;
  • the resonator further includes a protruding structure disposed on the lower side of the top electrode, at the electrode connection end of the top electrode, the protruding structure defines an upper surface of the second acoustic impedance mismatching structure.
  • a method of manufacturing a bulk acoustic wave resonator comprising:
  • Step 1 forming a bottom electrode and a first piezoelectric layer covering the bottom electrode;
  • Step 2 forming a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer is at least used to form a first acoustic impedance mismatch structure;
  • Step 3 forming a patterned second piezoelectric layer, the middle part of the second piezoelectric layer covers the upper surface of the first piezoelectric layer, and the edge part covers the upper surface of the patterned dielectric layer to form a cantilever structure ;
  • Step 4 covering the structure formed in step 3 with a metal layer, patterning the metal layer, and the patterned metal layer includes a top electrode.
  • the patterned medium layer is a sacrificial material layer
  • the method further includes step 5: releasing the sacrificial material layer to define the first acoustic impedance mismatch structure between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer.
  • the patterned medium layer includes a first sacrificial material layer for forming the first acoustic impedance mismatch structure, and a second sacrificial material layer for forming the second acoustic impedance mismatch structure, an electrode connection end of the top electrode, the first sacrificial material layer and the second sacrificial material layer are in contact with each other; and
  • step 5 releasing the second sacrificial material layer to form the second acoustic impedance mismatching structure is also included.
  • a filter comprising the bulk acoustic wave resonator according to any one of 1-13.
  • An electronic device comprising the filter according to 18, or the bulk acoustic wave resonator according to any one of 1-13.
  • the electronic equipment here includes but is not limited to intermediate products such as RF front-ends, filter amplifier modules, and terminal products such as mobile phones, WIFI, and drones.

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Abstract

The present invention relates to a bulk acoustic resonator and a manufacturing method therefor. The resonator comprises a substrate, a bottom electrode, an acoustic mirror, a top electrode, and a piezoelectric layer. The bottom electrode at least comprises a first electrode layer and a second electrode layer which are arranged in a thickness direction of the resonator. A gap layer is provided between the first electrode layer and the second electrode layer, and the acoustic mirror of the resonator is defined by the gap layer. The piezoelectric layer comprises a first piezoelectric layer and a second piezoelectric layer. The second piezoelectric layer is located on an upper side of the first piezoelectric layer, and an end portion of the second piezoelectric layer forms a suspension wing structure along an effective area of the resonator. A first acoustic impedance mismatch structure is defined between a lower surface of the suspension wing structure and an upper surface of the first piezoelectric layer. The present invention further relates to a filter and an electronic device.

Description

具有双压电层的体声波谐振器、滤波器及电子设备Bulk acoustic wave resonators, filters and electronics with double piezoelectric layers 技术领域technical field
本发明的实施例涉及半导体领域，尤其涉及一种体声波谐振器及其制造方法、一种具有该谐振器的滤波器以及一种电子设备。Embodiments of the present invention relate to the field of semiconductors, and in particular to a bulk acoustic wave resonator and a manufacturing method thereof, a filter with the resonator, and an electronic device.
背景技术Background technique
电子器件作为电子设备的基本元素，已经被广泛应用，其应用范围包括移动电话、汽车、家电设备等。此外，未来即将改变世界的人工智能、物联网、5G通讯等技术仍然需要依靠电子器件作为基础。As the basic elements of electronic equipment, electronic devices have been widely used, including mobile phones, automobiles, home appliances, etc. In addition, technologies such as artificial intelligence, the Internet of Things, and 5G communications that will change the world in the future still need to rely on electronic devices as the basis.
薄膜体声波谐振器(Film Bulk Acoustic Resonator，简称FBAR，又称为体声波谐振器，也称BAW)作为压电器件的重要成员正在通信领域发挥着重要作用，特别是FBAR滤波器在射频滤波器领域市场占有份额越来越大，FBAR具有尺寸小、谐振频率高、品质因数高、功率容量大、滚降效应好等优良特性，其滤波器正在逐步取代传统的声表面波(SAW)滤波器和陶瓷滤波器，在无线通信射频领域发挥巨大作用，其高灵敏度的优势也能应用到生物、物理、医学等传感领域。Film Bulk Acoustic Resonator (FBAR, also known as Bulk Acoustic Resonator, also known as BAW), as an important member of piezoelectric devices, is playing an important role in the field of communication, especially FBAR filters in radio frequency filters The field market share is increasing. FBAR has excellent characteristics such as small size, high resonance frequency, high quality factor, large power capacity, and good roll-off effect. Its filters are gradually replacing traditional surface acoustic wave (SAW) filters. And ceramic filters play a huge role in the radio frequency field of wireless communication, and its high sensitivity advantages can also be applied to sensing fields such as biology, physics, and medicine.
薄膜体声波谐振器的结构主体为由电极-压电薄膜-电极组成的“三明治”结构，即两层金属电极层之间夹一层压电材料。通过在两电极间输入正弦信号，FBAR利用逆压电效应将输入电信号转换为机械谐振，并且再利用压电效应将机械谐振转换为电信号输出。The structural body of the film bulk acoustic resonator is a "sandwich" structure composed of electrodes-piezoelectric film-electrodes, that is, a layer of piezoelectric material is sandwiched between two layers of metal electrode layers. By inputting a sinusoidal signal between two electrodes, FBAR uses the inverse piezoelectric effect to convert the input electrical signal into a mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output.
提升体声波谐振器的并联阻抗有利于提升谐振器的性能。目前已知的提升体声波谐振器并联阻抗的方法为在压电层与顶电极之间加入一层空气层或介质层。图1中示出了已知的体声波谐振器的截面示意图，该谐振器包括基底101、声学镜102、底电极层103、压电层104、空气层或介质层105、顶电极106、钝化层或工艺层107。Increasing the parallel impedance of the bulk acoustic wave resonator is beneficial to improve the performance of the resonator. A currently known method for increasing the parallel impedance of a BAW resonator is to add an air layer or a dielectric layer between the piezoelectric layer and the top electrode. 1 shows a schematic cross-sectional view of a known BAW resonator, which includes a substrate 101, an acoustic mirror 102, a bottom electrode layer 103, a piezoelectric layer 104, an air layer or dielectric layer 105, a top electrode 106, a blunt layer or process layer 107.
然而，在图1所示结构的基础上，仍然有继续提升谐振器在串联和并联频率点处的性能的需求，以提升滤波器整体通带的插损表现。However, on the basis of the structure shown in Figure 1, there is still a need to continue to improve the performance of the resonators at the series and parallel frequency points, so as to improve the insertion loss performance of the overall passband of the filter.
发明内容Contents of the invention
为缓解或解决现有技术中的上述问题的至少一个方面，提出本发明。In order to alleviate or solve at least one aspect of the above-mentioned problems in the prior art, the present invention is proposed.
根据本发明的实施例的一个方面，提出了一种体声波谐振器，包括基底、底电极、声学镜、顶电极和压电层。底电极至少包括在谐振器的厚度方向上设置的第一电极层和第二电极层。第一电极层与第二电极层之间设置有空隙层，空隙层限定谐振器的声学镜。压电层包括第一压电层和第二压电层，第二压电层处于第一压电层的上侧，且第二压电层的端部沿谐振器的有效区域形成有悬翼结构。悬翼结构的下表面与第一压电层的上表面之间限定有第一声阻抗不匹配结构。According to an aspect of the embodiments of the present invention, a bulk acoustic wave resonator is provided, including a substrate, a bottom electrode, an acoustic mirror, a top electrode and a piezoelectric layer. The bottom electrode includes at least a first electrode layer and a second electrode layer disposed in a thickness direction of the resonator. A gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines an acoustic mirror of the resonator. The piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is formed with a cantilever along the effective area of the resonator structure. A first acoustic impedance mismatch structure is defined between the lower surface of the suspension wing structure and the upper surface of the first piezoelectric layer.
根据本发明的实施例的另一方面，提出了一种上述体声波谐振器的制造方法，包括：步骤1：形成底电极以及覆盖底电极的第一压电层，所述底电极至少包括在谐振器的厚度方向上设置的第一电极层和第二电极层，所述第一电极层与第二电极层之间设置有空隙层，所述空隙层限定谐振器的声学镜；步骤2：在第一压电层上形成图形化介质层，所述图形化介质层至少用于形成第一声阻抗不匹配结构；步骤3：形成图形化的第二压电层，所述第二压电层的中间部分覆盖第一压电层的上表面，边缘部分覆盖所述图形化介质层的上表面而形成悬翼结构；和步骤4：以金属层覆盖步骤3形成的结构，对该金属层图形化，图形化后的金属层包括顶电极。According to another aspect of the embodiments of the present invention, a method for manufacturing the above-mentioned bulk acoustic wave resonator is proposed, including: step 1: forming a bottom electrode and a first piezoelectric layer covering the bottom electrode, the bottom electrode includes at least A first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines an acoustic mirror of the resonator; step 2: Forming a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer is at least used to form a first acoustic impedance mismatch structure; Step 3: forming a patterned second piezoelectric layer, the second piezoelectric The middle part of the layer covers the upper surface of the first piezoelectric layer, and the edge part covers the upper surface of the patterned dielectric layer to form a cantilever structure; and step 4: covering the structure formed in step 3 with a metal layer, the metal layer patterning, the patterned metal layer includes the top electrode.
本发明的实施例还涉及一种滤波器，包括上述的体声波谐振器。Embodiments of the present invention also relate to a filter, including the above bulk acoustic wave resonator.
本发明的实施例也涉及一种电子设备，包括上述的滤波器或者上述的谐振器。Embodiments of the present invention also relate to an electronic device, including the above-mentioned filter or the above-mentioned resonator.
附图说明Description of drawings
以下描述与附图可以更好地帮助理解本发明所公布的各种实施例中的这些和其他特点、优点，图中相同的附图标记始终表示相同的部件，其中：These and other features and advantages of the various disclosed embodiments of the present invention can be better understood from the following description and accompanying drawings, in which the same reference numerals refer to the same parts throughout, wherein:
图1为已知的体声波谐振器的截面示意图；Fig. 1 is a schematic cross-sectional view of a known bulk acoustic wave resonator;
图2A为根据本发明的一个示例性实施例的体声波谐振器的截面示意图；2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;
图2B为根据本发明的另一个示例性实施例的体声波谐振器的截面示意图；2B is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention;
图3为图1所示谐振器与图2A所示谐振器的并联阻抗的比较图；Fig. 3 is a comparison diagram of the parallel impedance of the resonator shown in Fig. 1 and the resonator shown in Fig. 2A;
图4-7为根据本发明的不同示例性实施例的体声波谐振器的截面示意 图；以及4-7 are schematic cross-sectional views of bulk acoustic wave resonators according to different exemplary embodiments of the present invention; and
图8-11为根据本发明的一个示例性实施例的示意性示出图2中的体声波谐振器的制造过程的截面示意图。8-11 are schematic cross-sectional views schematically showing the manufacturing process of the bulk acoustic wave resonator in FIG. 2 according to an exemplary embodiment of the present invention.
具体实施方式Detailed ways
下面通过实施例，并结合附图，对本发明的技术方案作进一步具体的说明。在说明书中，相同或相似的附图标号指示相同或相似的部件。下述参照附图对本发明实施方式的说明旨在对本发明的总体发明构思进行解释，而不应当理解为对本发明的一种限制。发明的一部分实施例，而并不是全部的实施例。基于本发明中的实施例，本领域普通技术人员所获得的所有其他实施例，都属于本发明保护的范围。The technical solutions of the present invention will be further specifically described below through the embodiments and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals designate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention, but should not be construed as a limitation of the present invention. Some, but not all, embodiments of the invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention belong to the protection scope of the present invention.
本发明提出一种带有双层压电层的体声波谐振器结构，其中，上压电层在谐振器的有效区域的边缘形成悬翼结构，该悬翼结构限定声阻抗不匹配结构，从而有利于提升谐振器的并联阻抗，从而提升谐振器的性能。The present invention proposes a bulk acoustic wave resonator structure with double piezoelectric layers, wherein the upper piezoelectric layer forms a cantilevered structure at the edge of the active area of the resonator, the cantilevered structure defines an acoustic impedance mismatch structure, thereby It is beneficial to increase the parallel impedance of the resonator, thereby improving the performance of the resonator.
本发明中的附图标记说明如下：Reference numerals in the present invention are explained as follows:
101：基底，可选材料为单晶硅、氮化镓、砷化镓、蓝宝石、石英、碳化硅、金刚石等。101: substrate, the optional material is single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
102：声学镜，可为空腔，例也可采用布拉格反射层及其他等效形式。102: Acoustic mirror, which can be a cavity, for example, Bragg reflection layer and other equivalent forms can also be used.
103：底电极层，材料可选钼、钌、金、铝、镁、钨、铜，钛、铱、锇、铬或以上金属的复合或其合金等。103: Bottom electrode layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or alloys thereof.
104：第一压电层，材料可以为氮化铝、氮化镓、铌酸锂、锆钛酸铅(PZT)、铌酸钾、石英薄膜、氧化锌等，还可是包含上述材料的一定原子比的稀土元素掺杂材料，例如可以是掺杂氮化铝，掺杂氮化铝至少含一种稀土元素，如钪(Sc)、钇(Y)、镁(Mg)、钛(Ti)、镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钷(Pm)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)等。104: The first piezoelectric layer, the material can be aluminum nitride, gallium nitride, lithium niobate, lead zirconate titanate (PZT), potassium niobate, quartz film, zinc oxide, etc., or certain atoms containing the above materials The ratio of rare earth element doping materials, such as doped aluminum nitride, doped aluminum nitride contains at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), Lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu), etc.
104’：第二压电层，材料可以与第一压电层104的材料相同。104': the second piezoelectric layer, the material of which can be the same as that of the first piezoelectric layer 104.
105：声阻抗不匹配结构：材料可以是空气、SiO 2、SiN等。 105: Acoustic impedance mismatch structure: the material can be air, SiO 2 , SiN, etc.
105A：第一声阻抗不匹配结构。105A: The first acoustic impedance mismatch structure.
105B：第二声阻抗不匹配结构。105B: The second acoustic impedance mismatch structure.
106：顶电极，材料可选钼、钌、金、铝、镁、钨、铜，钛、铱、锇、 铬或以上金属的复合或其合金等。顶电极和底电极材料一般相同，但也可以不同。106: The top electrode, the material of which can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or alloys thereof. The top and bottom electrodes are typically of the same material, but can also be different.
107：介质层或工艺层，其材料一般为介质材料，例如可以为氮化铝、二氧化硅、氮化硅等。如能够理解的，也可以不设置介质层或工艺层。107: A dielectric layer or a process layer, the material of which is generally a dielectric material, such as aluminum nitride, silicon dioxide, silicon nitride, etc. As can be understood, no dielectric layer or process layer may be provided.
112：种子层或者阻挡层，材料可选AlN、SiN等。如能够理解的，也可以不设置种子层或阻挡层112。112: a seed layer or a barrier layer, the material of which may be AlN, SiN or the like. As can be understood, the seed layer or barrier layer 112 may also not be provided.
113：底电极层，材料可选钼、钌、金、铝、镁、钨、铜，钛、铱、锇、铬或以上金属的复合或其合金等，底电极层103与底电极层113的材料可以不同。如能够理解的。113: The bottom electrode layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or their alloys, etc., the bottom electrode layer 103 and the bottom electrode layer 113 Materials can vary. as can be understood.
114：凸起结构，材料可选钼，钌，金，铝，镁，钨，铜，钛，铱，锇，铬或以上金属的符合或其合金等，也可以不设置凸起结构。114: Protruding structure, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the metals above or their alloys, etc., and the protruding structure may not be provided.
115：声学镜牺牲层，材料可以是AlN、SiN、SiO 2等。 115: Acoustic mirror sacrificial layer, the material can be AlN, SiN, SiO 2 and so on.
116：凹陷结构形成层，材料可选钼，钌，金，铝，镁，钨，铜，钛，铱，锇，铬或以上金属的符合或其合金等。116: The concave structure forming layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the above metals or their alloys.
118：声阻抗不匹配结构牺牲层，材料可以是AlN、SiN、SiO 2等。 118: Acoustic impedance mismatch structure sacrificial layer, the material may be AlN, SiN, SiO 2 and so on.
图2A为根据本发明的一个示例性实施例的体声波谐振器的截面示意图。如图2A所示，体声波谐振器包括：基底101；声学镜102，在图2中其为空腔或空隙层的形式；底电极，包括底电极层103和底电极层113，声学镜102处于底电极层103与底电极层113之间；顶电极106；和第一压电层104和第二压电层104’。FIG. 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. As shown in Figure 2A, the BAW resonator includes: a substrate 101; an acoustic mirror 102, which is in the form of a cavity or a void layer in Figure 2; a bottom electrode, including a bottom electrode layer 103 and a bottom electrode layer 113, and the acoustic mirror 102 between the bottom electrode layer 103 and the bottom electrode layer 113; the top electrode 106; and the first piezoelectric layer 104 and the second piezoelectric layer 104'.
如图2A所示，第二压电层104’处于第一压电层104的上侧，且第二压电层104’的端部沿谐振器的有效区域的至少一部分形成有悬翼结构，所述悬翼结构的下表面与第一压电层104的上表面之间限定有声阻抗不匹配结构105A，在该声阻抗不匹配结构105A为空气构成的情况下，可以看到，沿谐振器的有效区域，空气层设置在两个压电层之间。As shown in FIG. 2A, the second piezoelectric layer 104' is on the upper side of the first piezoelectric layer 104, and the end of the second piezoelectric layer 104' is formed with a cantilever structure along at least a part of the effective area of the resonator, An acoustic impedance mismatch structure 105A is defined between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer 104. In the case where the acoustic impedance mismatch structure 105A is made of air, it can be seen that along the resonator In the effective area of , the air layer is set between the two piezoelectric layers.
此外，如图2A所示，在顶电极的电极连接端，谐振器还设置有声阻抗不匹配结构105B，声阻抗不匹配结构105A和105B在水平方向上彼此相接。即，图2A所示的谐振器形成有桥结构，所述桥结构的下表面与第一压电层104的上表面之间形成有声阻抗不匹配结构105B，声阻抗不匹配结构105A与声阻抗不匹配结构105B彼此相接。In addition, as shown in FIG. 2A , at the electrode connection end of the top electrode, the resonator is also provided with an acoustic impedance mismatch structure 105B, and the acoustic impedance mismatch structures 105A and 105B are connected to each other in the horizontal direction. That is, the resonator shown in FIG. 2A is formed with a bridge structure, an acoustic impedance mismatching structure 105B is formed between the lower surface of the bridge structure and the upper surface of the first piezoelectric layer 104, and the acoustic impedance mismatching structure 105A and the acoustic impedance The mismatched structures 105B are in contact with each other.
图3为图1所示谐振器与图2A所示谐振器的并联阻抗的比较图，其 中将图1所示的谐振器并联阻抗定义为1，则如图2A所示的谐振器的并联阻抗为1.4，这意味着图2A所示的谐振器的并联阻抗较图1的谐振器提升了40％。Fig. 3 is a comparison diagram of the parallel impedance of the resonator shown in Fig. 1 and the resonator shown in Fig. 2A, wherein the resonator parallel impedance shown in Fig. 1 is defined as 1, then the parallel impedance of the resonator shown in Fig. 2A is 1.4, which means that the parallel impedance of the resonator shown in FIG. 2A is 40% higher than that of the resonator in FIG. 1 .
在图2A中，在顶电极的电极连接端，还设置有桥结构从而谐振器还形成有声阻抗不匹配结构105B，但是本发明不限于此，换言之，还可以仅仅保留除顶电极的电极连接端之外处的至少一部分声阻抗不匹配结构105A，从而不设置声阻抗不匹配结构105B，而且在顶电极的电极连接端压电层也没有设置悬翼结构，图2B中示出了这样的谐振器结构。图2B所示的仅仅设置声阻抗不匹配结构105A而不设置声阻抗不匹配结构105B的情形，也可以应用到本发明的例如后面提及的图4-图7所示的实施例中。In FIG. 2A, a bridge structure is also provided at the electrode connection end of the top electrode so that the resonator also forms an acoustic impedance mismatch structure 105B, but the present invention is not limited thereto. In other words, only the electrode connection end of the top electrode can be reserved. At least a part of the acoustic impedance mismatching structure 105A outside, so that the acoustic impedance mismatching structure 105B is not provided, and the piezoelectric layer at the electrode connection end of the top electrode is not provided with a cantilever structure. Such a resonance is shown in FIG. 2B device structure. The situation in which only the acoustic impedance mismatching structure 105A is provided without the acoustic impedance mismatching structure 105B shown in FIG. 2B can also be applied to embodiments of the present invention such as those shown in FIGS. 4-7 mentioned later.
此外，可选的，在图2A所示的实施例中，在顶电极的电极连接端，第一压电层104的上表面限定声阻抗不匹配结构105A与声阻抗不匹配结构105B相接的部分的下表面，声阻抗不匹配结构105A与声阻抗不匹配结构105B相接的部分的上表面齐平。In addition, optionally, in the embodiment shown in FIG. 2A , at the electrode connection end of the top electrode, the upper surface of the first piezoelectric layer 104 defines a junction between the acoustic impedance mismatch structure 105A and the acoustic impedance mismatch structure 105B. The lower surface of the part is flush with the upper surface of the part where the acoustic impedance mismatching structure 105A and the acoustic impedance mismatching structure 105B meet.
在图2A和图2B中，谐振器还包括介质层或工艺层107，如前所述的，也可以不设置介质层或工艺层107。In FIG. 2A and FIG. 2B , the resonator further includes a dielectric layer or process layer 107 , as mentioned above, the dielectric layer or process layer 107 may not be provided.
在图2A和图2B所示的实施例中，如能够理解的，底电极可以不仅仅为两层电极，还可以更多个电极层。在底电极采用双层电极或更多层电极的情况下，有利于降低电极的电阻损耗，从而降低了谐振器的串联阻抗。In the embodiment shown in FIG. 2A and FIG. 2B , as can be understood, the bottom electrode can be not only two layers of electrodes, but also more electrode layers. In the case that the bottom electrode adopts double-layer electrodes or more electrodes, it is beneficial to reduce the resistance loss of the electrodes, thereby reducing the series impedance of the resonator.
对于图2A和图2B所示结构的谐振器，在底电极103替换为多层电极的情况下，不仅可以通过基于第二压电层104’设置悬翼结构而提升谐振器的并联阻抗，而且可以通过降低底电极的电阻损耗而降低谐振器的串联阻抗。在提升谐振器的并联阻抗的同时降低谐振器的串联阻抗，可以使得使用本发明谐振器制造的滤波器提升整体通带的插损。For the resonator with the structure shown in Figure 2A and Figure 2B, in the case where the bottom electrode 103 is replaced by a multilayer electrode, not only the parallel impedance of the resonator can be improved by setting the cantilever structure based on the second piezoelectric layer 104', but also The series impedance of the resonator can be reduced by reducing the resistive losses of the bottom electrode. By reducing the series impedance of the resonator while increasing the parallel impedance of the resonator, the filter manufactured by using the resonator of the present invention can increase the insertion loss of the overall passband.
在本发明中，声阻抗不匹配结构105A可以沿谐振器的整个有效区域设置，也可以仅仅沿部分区域设置，均在本发明的保护范围之内。In the present invention, the acoustic impedance mismatch structure 105A can be arranged along the entire effective area of the resonator, or only along a part of the area, all within the protection scope of the present invention.
在本发明的一个实施例中，例如参见图2A和图2B，声阻抗不匹配结构105A的内侧边界处于声学镜102的边界的内侧，从而限定谐振器的有效区域的边界。在本发明的不同实施例中，虽然没有示出，声阻抗不匹配结构105A的内侧边界可以仅仅限定有效区域的部分边界或者不限定有效区域的边界，这些也在本发明的保护范围之内。In one embodiment of the invention, see eg FIGS. 2A and 2B , the inner boundary of the acoustic impedance mismatch structure 105A is inboard of the boundary of the acoustic mirror 102 , thereby defining the boundary of the active area of the resonator. In different embodiments of the present invention, although not shown, the inner boundary of the acoustic impedance mismatch structure 105A may only define a part of the boundary of the effective area or not define the boundary of the effective area, and these are also within the protection scope of the present invention.
在图2A-2B所示的结构中，底电极为多层电极且空隙层夹在电极层之间而形成声学镜，此时可以降低底电极的电阻损耗从而降低了谐振器的串联阻抗。In the structure shown in FIGS. 2A-2B , the bottom electrode is a multilayer electrode and the gap layer is sandwiched between the electrode layers to form an acoustic mirror. At this time, the resistance loss of the bottom electrode can be reduced to reduce the series impedance of the resonator.
在图2A所示的一个可选实施例中，谐振器还设置有阻挡层或种子层112。在底电极103例如为含铝的金属层的情况下，该阻挡层112可以在释放或刻蚀后续提及的用于声学镜的牺牲层时可以起到保护底电极103的作用。但是，如前提及的，也可以不设置阻挡层或种子层112。In an alternative embodiment shown in FIG. 2A , the resonator is also provided with a barrier or seed layer 112 . In the case that the bottom electrode 103 is, for example, a metal layer containing aluminum, the barrier layer 112 can protect the bottom electrode 103 when releasing or etching the later-mentioned sacrificial layer for the acoustic mirror. However, as mentioned before, the barrier or seed layer 112 may also be omitted.
在本发明的一个实施例中，为了进一步增加声阻抗不匹配的界限数量，还可以在图2A所示的结构中设置台阶部，图4中示出了这样的谐振器结构。如图4所示，其圆圈标出的位置增加了台阶部，从而进一步增加阻抗不匹配界限的数量，进一步限制谐振器的横波泄露。In an embodiment of the present invention, in order to further increase the limit amount of acoustic impedance mismatch, a step portion may also be provided in the structure shown in FIG. 2A . Such a resonator structure is shown in FIG. 4 . As shown in FIG. 4 , a stepped portion is added at the position marked by a circle, thereby further increasing the number of impedance mismatch boundaries and further limiting the shear wave leakage of the resonator.
如图4所示，限定声阻抗不匹配结构105B的上表面的桥结构的下表面设置有上台阶部A(图4中示出圆圈A)，且限定声阻抗不匹配结构105B的下表面的第一压电层104的上表面设置有下台阶部B(图4中示出圆圈B)。As shown in FIG. 4 , the lower surface of the bridge structure defining the upper surface of the acoustic impedance mismatching structure 105B is provided with an upper step portion A (circle A is shown in FIG. 4 ), and the lower surface defining the lower surface of the acoustic impedance mismatching structure 105B The upper surface of the first piezoelectric layer 104 is provided with a lower step portion B (a circle B is shown in FIG. 4 ).
在图4所示的实施例中，桥结构直接由谐振器的顶电极的电极连接端形成，具体的，桥结构的下表面即顶电极的电极连接端的下表面。如后面参照图6说明的，桥结构还可以包括凸起结构，此时，可以在凸起结构的下表面设置有上台阶部A。In the embodiment shown in FIG. 4 , the bridge structure is directly formed by the electrode connection end of the top electrode of the resonator, specifically, the lower surface of the bridge structure is the lower surface of the electrode connection end of the top electrode. As explained later with reference to FIG. 6 , the bridge structure may also include a protruding structure. In this case, an upper step portion A may be provided on the lower surface of the protruding structure.
在图4所示的实施例中，上台阶部形成在桥结构的下表面，而下台阶部则设置在第一压电层104的上表面。如能够理解的，图4所示的实施例中，可以仅仅设置上台阶部，也可以仅仅设置下台阶部，当然也可以如图4所示同时设置上台阶部和下台阶部。在图4所示的实施例中，上台阶部和下台阶部的数量不做限定。In the embodiment shown in FIG. 4 , the upper stepped portion is formed on the lower surface of the bridge structure, while the lower stepped portion is disposed on the upper surface of the first piezoelectric layer 104 . As can be understood, in the embodiment shown in FIG. 4 , only the upper step portion or the lower step portion may be provided, and of course both the upper step portion and the lower step portion may be provided as shown in FIG. 4 . In the embodiment shown in FIG. 4 , the number of the upper step portion and the lower step portion is not limited.
在进一步的实施例中，如图4所示，上台阶部A在水平方向上设置在声阻抗不匹配结构105A与声学镜102的边界之间。In a further embodiment, as shown in FIG. 4 , the upper stepped portion A is disposed between the acoustic impedance mismatch structure 105A and the boundary of the acoustic mirror 102 in the horizontal direction.
在进一步的实施例中，如图4所示，下台阶部B在水平方向上设置在底电极的非电极连接端的外侧。In a further embodiment, as shown in FIG. 4 , the lower step portion B is arranged outside the non-electrode connection end of the bottom electrode in the horizontal direction.
在可选的实施例中，如图4所示，在底电极的电极连接端，第一压电层104的上表面在声学镜102边界的外侧设置有另外的台阶部C(图4中示出圆圈C)。In an optional embodiment, as shown in FIG. 4 , at the electrode connection end of the bottom electrode, the upper surface of the first piezoelectric layer 104 is provided with another step portion C (shown in FIG. 4 ) outside the boundary of the acoustic mirror 102 . Out of the circle C).
对于声阻抗不匹配结构105B，其上表面可以直接由顶电极的电极连接端的下表面限定，如图2A-2B以及图4-5所示。可选的，在另外的实施例中，在谐振器的顶电极的下侧设置有凸起结构的情况下，声阻抗不匹配结构105B的上表面可以直接由该凸起结构的下表面限定，如后面提及的图6和图7所示。For the acoustic impedance mismatch structure 105B, its upper surface may be directly defined by the lower surface of the electrode connection end of the top electrode, as shown in FIGS. 2A-2B and FIGS. 4-5 . Optionally, in another embodiment, in the case where a protruding structure is provided on the underside of the top electrode of the resonator, the upper surface of the acoustic impedance mismatch structure 105B may be directly defined by the lower surface of the protruding structure, As shown in FIGS. 6 and 7 mentioned later.
在图2A-2B以及图4中，在顶电极的非电极连接端，第二压电层104’上侧的膜层的端面与第二压电层104’的端面齐平，但是本发明不限于。在顶电极的非电极连接端，第二压电层104’上侧的至少一个膜层的端面也可以与第二压电层104’的端面在水平方向上错开，图5示出了这样的一个示例性结构。在图5中，第二压电层104’上侧的膜层的端面均处于第二压电层104’的端面的内侧，在可选的实施例中，上侧的至少一个膜层的端面也可以处于第二压电层的端面的外侧。除了在顶电极的非电极连接端第二压电层上侧膜层的端面与第二压电层的端面错开之外，图5所示结构与图2A所示结构相似，这里不再赘述。2A-2B and FIG. 4, at the non-electrode connection end of the top electrode, the end face of the film layer on the upper side of the second piezoelectric layer 104' is flush with the end face of the second piezoelectric layer 104', but the present invention does not limited to. At the non-electrode connection end of the top electrode, the end surface of at least one film layer on the upper side of the second piezoelectric layer 104' may also be horizontally staggered from the end surface of the second piezoelectric layer 104', as shown in FIG. 5 An exemplary structure. In FIG. 5 , the end faces of the film layers on the upper side of the second piezoelectric layer 104 ′ are all inside the end faces of the second piezoelectric layer 104 ′. In an optional embodiment, the end faces of at least one film layer on the upper side It may also be located outside the end surface of the second piezoelectric layer. The structure shown in FIG. 5 is similar to the structure shown in FIG. 2A except that the end face of the film layer on the second piezoelectric layer at the non-electrode connection end of the top electrode is staggered from the end face of the second piezoelectric layer, and will not be repeated here.
为了进一步增加谐振器的并联阻抗，还可以在谐振器中增加凸起结构，图6中示出了这样的一个示例性结构。在图6中，谐振器还包括设置在顶电极106下侧的凸起结构114，在顶电极的电极连接端，凸起结构114限定声阻抗不匹配结构105B的上表面。除了另外设置凸起结构114之外，图6所示结构与图2A所示结构相似，这里不再赘述。In order to further increase the parallel impedance of the resonator, a protruding structure may also be added in the resonator, such an exemplary structure is shown in FIG. 6 . In FIG. 6, the resonator further includes a protruding structure 114 disposed on the lower side of the top electrode 106, and at the electrode connection end of the top electrode, the protruding structure 114 defines the upper surface of the acoustic impedance mismatch structure 105B. The structure shown in FIG. 6 is similar to the structure shown in FIG. 2A except that the protruding structure 114 is additionally provided, and details are not repeated here.
为了减弱串联谐振频率以下的寄生模式强度，谐振器还可以设置凹陷结构，图7中示例性示出了这样的谐振器结构。如图7所示，在顶电极106的上侧还设置有凹陷结构形成层116，其用于在其边缘形成凹陷结构。除了另外设置凹陷结构之外，图7所示结构与图6所示结构相似，这里不再赘述。In order to weaken the intensity of spurious modes below the series resonance frequency, the resonator may also be provided with a recessed structure, and such a resonator structure is exemplarily shown in FIG. 7 . As shown in FIG. 7 , on the upper side of the top electrode 106 is also provided a recessed structure forming layer 116 for forming a recessed structure at its edge. The structure shown in FIG. 7 is similar to the structure shown in FIG. 6 except that a recess structure is additionally provided, and details are not repeated here.
下面参照图8-11示例性说明图2A所示的谐振器结构的制造过程。The manufacturing process of the resonator structure shown in FIG. 2A is exemplarily described below with reference to FIGS. 8-11 .
如图8所示，提供基底101，在基底101上沉积用于形成底电极层113的金属层，然后在该金属层上沉积并图形化声学镜牺牲材料层115(即以声学镜为空腔为例)，接着沉积和图形化种子层112，之后沉积用于形成底电极层103的金属层，对两个金属层图形化以形成底电极，如图8所示。底电极层103和底电极层113的材料可以相同。在进一步可选的实施例中，底电极层103和底电极层113的材料可以不同，可以是图8中的底电极层 103的声阻抗高于底电极层113的声阻抗，图8中的底电极层113的导电率高于底电极层103的导电率。As shown in Figure 8, a substrate 101 is provided, a metal layer for forming a bottom electrode layer 113 is deposited on the substrate 101, and then the acoustic mirror sacrificial material layer 115 is deposited and patterned on the metal layer (that is, the acoustic mirror is a cavity For example), then deposit and pattern the seed layer 112, then deposit the metal layer for forming the bottom electrode layer 103, and pattern the two metal layers to form the bottom electrode, as shown in FIG. 8 . The material of the bottom electrode layer 103 and the bottom electrode layer 113 may be the same. In a further optional embodiment, the materials of the bottom electrode layer 103 and the bottom electrode layer 113 can be different. It can be that the acoustic impedance of the bottom electrode layer 103 in FIG. The conductivity of the bottom electrode layer 113 is higher than that of the bottom electrode layer 103 .
如图9所示，在图8所示结构的基础上，沉积第一压电层104。As shown in FIG. 9 , on the basis of the structure shown in FIG. 8 , a first piezoelectric layer 104 is deposited.
如图10所示，在图9所示结构的基础上，在第一压电层104的上表面沉积和图形化牺牲材料层(这里以声阻抗不匹配结构105为空腔为例，但是如能理解的，声阻抗不匹配结构可以直接是不用释放的介质层)以形成声阻抗不匹配结构牺牲层118。As shown in FIG. 10, on the basis of the structure shown in FIG. 9, a sacrificial material layer is deposited and patterned on the upper surface of the first piezoelectric layer 104 (here, the acoustic impedance mismatch structure 105 is used as a cavity as an example, but as It can be understood that the acoustic impedance mismatch structure may directly be a dielectric layer without release) to form the acoustic impedance mismatch structure sacrificial layer 118 .
如图11所示，在图10所示结构的基础上，沉积和图形化第二压电层104’，以形成如图11所示的结构。As shown in FIG. 11 , on the basis of the structure shown in FIG. 10 , a second piezoelectric layer 104' is deposited and patterned to form the structure shown in FIG. 11 .
虽然没有示出，之后，可以依次沉积和图形化而形成顶电极106和工艺层107，接着，可以释放声学镜牺牲材料层115以形成声学镜102，释放声阻抗不匹配结构牺牲层118以形成声阻抗不匹配结构105A和105B，从而得到图2A所示的谐振器结构。Although not shown, thereafter, the top electrode 106 and the process layer 107 can be formed by sequential deposition and patterning, and then the acoustic mirror sacrificial material layer 115 can be released to form the acoustic mirror 102, and the acoustic impedance mismatch structure sacrificial layer 118 can be released to form Acoustically impedance-mismatched structures 105A and 105B result in the resonator structure shown in Figure 2A.
在本发明的一个实施例中，谐振器中沿有效区域设置的凸起结构和/或凹陷结构，不限于例如图6和图7所示的位置。例如，对于凸起结构，其也可以设置在压电层中，或者设置在压电层与底电极之间等。这些均在本发明的保护范围之内。In an embodiment of the present invention, the protruding structures and/or concave structures disposed along the effective area in the resonator are not limited to the positions shown in FIG. 6 and FIG. 7 , for example. For example, for the protrusion structure, it may also be disposed in the piezoelectric layer, or disposed between the piezoelectric layer and the bottom electrode, and the like. These are all within the protection scope of the present invention.
在本发明中，上和下是相对于谐振器的基底的底面而言的，对于一个部件，其靠近该底面的一侧为下侧，远离该底面的一侧为上侧。In the present invention, up and down are relative to the bottom surface of the base of the resonator. For a component, the side close to the bottom surface is the bottom side, and the side away from the bottom surface is the top side.
在本发明中，内和外是相对于谐振器的有效区域(压电层、顶电极、底电极和声学镜在谐振器的厚度方向上的重叠区域构成有效区域)的中心(即有效区域中心)在横向方向或者径向方向上而言的，一个部件的靠近有效区域中心的一侧或一端为内侧或内端，而该部件的远离有效区域中心的一侧或一端为外侧或外端。对于一个参照位置而言，位于该位置的内侧表示在横向方向或径向方向上处于该位置与有效区域中心之间，位于该位置的外侧表示在横向方向或径向方向上比该位置更远离有效区域中心。In the present invention, inner and outer are relative to the center of the effective area of the resonator (the overlapping area of the piezoelectric layer, the top electrode, the bottom electrode and the acoustic mirror in the thickness direction of the resonator constitutes the effective area) (i.e. the center of the effective area ) In terms of the transverse or radial direction, the side or end of a component that is close to the center of the effective area is the inner or inner end, while the side or end of the component that is far from the center of the effective area is the outer or outer end. For a reference position, being located inside the position means that it is between the position and the center of the effective area in the lateral direction or radial direction, and being located outside the position means that it is farther away from the position in the lateral direction or radial direction. Effective area center.
如本领域技术人员能够理解的，根据本发明的体声波谐振器可以用于形成滤波器或电子设备。As can be understood by those skilled in the art, the bulk acoustic wave resonator according to the present invention can be used to form filters or electronic devices.
基于以上，本发明提出了如下技术方案：Based on the above, the present invention proposes the following technical solutions:
1、一种体声波谐振器，包括：1. A bulk acoustic wave resonator, comprising:
基底；base;
底电极；bottom electrode;
声学镜；acoustic mirror;
顶电极；和top electrode; and
压电层，piezoelectric layer,
其中：in:
所述底电极至少包括在谐振器的厚度方向上设置的第一电极层和第二电极层，所述第一电极层与第二电极层之间设置有空隙层，所述空隙层限定谐振器的声学镜；以及The bottom electrode includes at least a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines the resonator acoustic mirrors; and
所述压电层包括第一压电层和第二压电层，第二压电层处于第一压电层的上侧，且第二压电层的端部沿谐振器的有效区域形成有悬翼结构，所述悬翼结构的下表面与第一压电层的上表面之间限定有第一声阻抗不匹配结构。The piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is formed along the effective area of the resonator The suspension wing structure, a first acoustic impedance mismatch structure is defined between the lower surface of the suspension wing structure and the upper surface of the first piezoelectric layer.
2、根据1所述的谐振器，其中，所述悬翼结构围绕整个所述有效区域设置。2. The resonator according to 1, wherein the suspension structure is arranged around the entire active area.
3、根据2所述的谐振器，其中，所述第一声阻抗不匹配结构的内侧边界限定所述有效区域的边界。3. The resonator according to 2, wherein the inner boundary of the first acoustic impedance mismatch structure defines the boundary of the active area.
4、根据1所述的谐振器，其中，形成所述第一声阻抗不匹配结构的材料包括空气、SiO 2或者SiN。 4. The resonator according to 1, wherein the material forming the first acoustic impedance mismatch structure includes air, SiO 2 or SiN.
5、根据1所述的谐振器，其中，在所述顶电极的电极连接端，所述谐振器形成有桥结构，所述桥结构的下表面与所述第一压电层的上表面之间形成有第二声阻抗不匹配结构，所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构彼此相接。5. The resonator according to 1, wherein at the electrode connection end of the top electrode, the resonator is formed with a bridge structure, and a bridge structure is formed between the lower surface of the bridge structure and the upper surface of the first piezoelectric layer. A second acoustic impedance mismatch structure is formed between them, and the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure are connected to each other.
6、根据5所述的谐振器，其中，形成所述第二声阻抗不匹配结构的材料包括空气、SiO 2或者SiN。 6. The resonator according to 5, wherein the material forming the second acoustic impedance mismatch structure includes air, SiO 2 or SiN.
7、根据5所述的谐振器，其中，在顶电极的电极连接端，所述第一压电层的上表面限定所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构相接的部分的下表面，所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构相接的部分的上表面齐平。7. The resonator according to 5, wherein at the electrode connection end of the top electrode, the upper surface of the first piezoelectric layer defines the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure The lower surface of the connected part, the upper surface of the connected part of the first acoustic impedance mismatching structure and the second acoustic impedance mismatching structure is flush.
8、根据5所述的谐振器，其中，限定所述第二声阻抗不匹配结构的上表面的所述桥结构的下表面设置有上台阶部，和/或限定所述第二声阻抗不匹配结构的下表面的所述第一压电层的上表面设置有下台阶部。8. The resonator according to 5, wherein the lower surface of the bridge structure defining the upper surface of the second acoustic impedance mismatching structure is provided with an upper stepped portion, and/or defines the second acoustic impedance mismatching structure. The upper surface of the first piezoelectric layer of the lower surface of the matching structure is provided with a lower stepped portion.
9、根据8所述的谐振器，其中：9. The resonator according to 8, wherein:
所述上台阶部在水平方向上设置在所述第一声阻抗不匹配结构与声学镜的边界之间；或者The upper step portion is disposed between the boundary of the first acoustic impedance mismatching structure and the acoustic mirror in the horizontal direction; or
所述下台阶部在水平方向上设置在底电极的非电极连接端的外侧。The lower step portion is disposed outside the non-electrode connection end of the bottom electrode in the horizontal direction.
10、根据9所述的谐振器，其中，在底电极的电极连接端，所述第一压电层的上表面在声学镜边界的外侧设置有另外的台阶部。10. The resonator according to 9, wherein at the electrode connection end of the bottom electrode, the upper surface of the first piezoelectric layer is provided with an additional stepped portion outside the boundary of the acoustic mirror.
11、根据5所述的谐振器，其中：11. The resonator according to 5, wherein:
所述第二声阻抗不匹配结构的上表面由顶电极的电极连接端限定；或者the upper surface of the second acoustic impedance mismatching structure is defined by the electrode connection end of the top electrode; or
所述谐振器还包括设置在顶电极下侧的凸起结构，在顶电极的电极连接端，所述凸起结构限定所述第二声阻抗不匹配结构的上表面。The resonator further includes a protruding structure disposed on the lower side of the top electrode, at the electrode connection end of the top electrode, the protruding structure defines an upper surface of the second acoustic impedance mismatching structure.
12、根据1所述的谐振器，其中，所述谐振器还包括沿有效区域设置凸起结构和/或凹陷结构。12. The resonator according to 1, wherein the resonator further comprises a convex structure and/or a concave structure disposed along the effective area.
13、根据1所述的谐振器，其中，在顶电极的非电极连接端，所述第二压电层上侧的至少一个膜层的端面与第二压电层的端面在水平方向上错开。13. The resonator according to 1, wherein at the non-electrode connection end of the top electrode, the end surface of at least one film layer on the upper side of the second piezoelectric layer is horizontally offset from the end surface of the second piezoelectric layer .
14、一种体声波谐振器的制造方法，包括：14. A method of manufacturing a bulk acoustic wave resonator, comprising:
步骤1：形成底电极以及覆盖底电极的第一压电层；Step 1: forming a bottom electrode and a first piezoelectric layer covering the bottom electrode;
步骤2：在第一压电层上形成图形化介质层，所述图形化介质层至少用于形成第一声阻抗不匹配结构；Step 2: forming a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer is at least used to form a first acoustic impedance mismatch structure;
步骤3：形成图形化的第二压电层，所述第二压电层的中间部分覆盖第一压电层的上表面，边缘部分覆盖所述图形化介质层的上表面而形成悬翼结构；和Step 3: forming a patterned second piezoelectric layer, the middle part of the second piezoelectric layer covers the upper surface of the first piezoelectric layer, and the edge part covers the upper surface of the patterned dielectric layer to form a cantilever structure ;and
步骤4：以金属层覆盖步骤3形成的结构，对该金属层图形化，图形化后的金属层包括顶电极。Step 4: covering the structure formed in step 3 with a metal layer, patterning the metal layer, and the patterned metal layer includes a top electrode.
15、根据14所述的方法，其中：15. The method according to 14, wherein:
所述图形化介质层为牺牲材料层；The patterned medium layer is a sacrificial material layer;
所述方法还包括步骤5：释放所述牺牲材料层，以悬翼结构的下表面与第一压电层的上表面之间限定所述第一声阻抗不匹配结构。The method further includes step 5: releasing the sacrificial material layer to define the first acoustic impedance mismatch structure between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer.
16、根据15所述的方法，其中：16. The method according to 15, wherein:
在步骤2中，所述图形化介质层包括用于形成所述第一声阻抗不匹配 结构的第一牺牲材料层，以及用于形成第二声阻抗不匹配结构的第二牺牲材料层，在顶电极的电极连接端，所述第一牺牲材料层与所述第二牺牲材料层彼此相接；以及In step 2, the patterned medium layer includes a first sacrificial material layer for forming the first acoustic impedance mismatch structure, and a second sacrificial material layer for forming the second acoustic impedance mismatch structure, an electrode connection end of the top electrode, the first sacrificial material layer and the second sacrificial material layer are in contact with each other; and
在步骤5中，还包括释放所述第二牺牲材料层以形成所述第二声阻抗不匹配结构。In step 5, releasing the second sacrificial material layer to form the second acoustic impedance mismatching structure is also included.
17、根据14-16中任一项所述的方法，其中，所述第一声阻抗不匹配结构的内端用于限定谐振器的有效区域的边界。17. The method according to any one of 14-16, wherein the inner end of the first acoustic impedance mismatch structure is used to define the boundary of the active area of the resonator.
18、一种滤波器，包括根据1-13中任一项所述的体声波谐振器。18. A filter comprising the bulk acoustic wave resonator according to any one of 1-13.
19、一种电子设备，包括根据18所述的滤波器，或者根据1-13中任一项所述的体声波谐振器。19. An electronic device comprising the filter according to 18, or the bulk acoustic wave resonator according to any one of 1-13.
这里的电子设备，包括但不限于射频前端、滤波放大模块等中间产品，以及手机、WIFI、无人机等终端产品。The electronic equipment here includes but is not limited to intermediate products such as RF front-ends, filter amplifier modules, and terminal products such as mobile phones, WIFI, and drones.
尽管已经示出和描述了本发明的实施例，对于本领域的普通技术人员而言，可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行变化，本发明的范围由所附权利要求及其等同物限定。While embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by The appended claims and their equivalents are defined.

Claims (19)

  1. 一种体声波谐振器，包括：A bulk acoustic wave resonator comprising:
    基底；base;
    底电极；bottom electrode;
    声学镜；acoustic mirror;
    顶电极；和top electrode; and
    压电层，piezoelectric layer,
    其中：in:
    所述底电极至少包括在谐振器的厚度方向上设置的第一电极层和第二电极层，所述第一电极层与第二电极层之间设置有空隙层，所述空隙层限定谐振器的声学镜；The bottom electrode includes at least a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, a gap layer is arranged between the first electrode layer and the second electrode layer, and the gap layer defines the resonator the acoustic mirror;
    所述压电层包括第一压电层和第二压电层，第二压电层处于第一压电层的上侧，且第二压电层的端部沿谐振器的有效区域形成有悬翼结构，所述悬翼结构的下表面与第一压电层的上表面之间限定有第一声阻抗不匹配结构。The piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is formed along the effective area of the resonator The suspension wing structure, a first acoustic impedance mismatch structure is defined between the lower surface of the suspension wing structure and the upper surface of the first piezoelectric layer.
  2. 根据权利要求1所述的谐振器，其中，所述悬翼结构围绕整个所述有效区域设置。The resonator according to claim 1, wherein said cantilever structure is arranged around the whole of said active area.
  3. 根据权利要求2所述的谐振器，其中，所述第一声阻抗不匹配结构的内侧边界限定所述有效区域的边界。The resonator of claim 2, wherein an inner boundary of the first acoustic impedance mismatch structure defines a boundary of the active area.
  4. 根据权利要求1所述的谐振器，其中，形成所述第一声阻抗不匹配结构的材料包括空气、SiO 2或者SiN。 The resonator according to claim 1, wherein the material forming the first acoustic impedance mismatch structure comprises air, SiO 2 or SiN.
  5. 根据权利要求1所述的谐振器，其中，在所述顶电极的电极连接端，所述谐振器形成有桥结构，所述桥结构的下表面与所述第一压电层的上表面之间形成有第二声阻抗不匹配结构，所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构彼此相接。The resonator according to claim 1, wherein at the electrode connection end of the top electrode, the resonator is formed with a bridge structure, and a lower surface of the bridge structure is connected to an upper surface of the first piezoelectric layer. A second acoustic impedance mismatch structure is formed between them, and the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure are connected to each other.
  6. 根据权利要求5所述的谐振器，其中，形成所述第二声阻抗不匹配结构的材料包括空气、SiO 2或者SiN。 The resonator according to claim 5, wherein the material forming the second acoustic impedance mismatch structure comprises air, SiO 2 or SiN.
  7. 根据权利要求5所述的谐振器，其中，在顶电极的电极连接端，所述第一压电层的上表面限定所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构相接的部分的下表面，所述第一声阻抗不匹配结构与所述第二声阻抗不匹配结构相接的部分的上表面齐平。The resonator according to claim 5, wherein at the electrode connection end of the top electrode, the upper surface of the first piezoelectric layer defines the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure The lower surface of the connected part, the upper surface of the connected part of the first acoustic impedance mismatching structure and the second acoustic impedance mismatching structure is flush.
  8. 根据权利要求5所述的谐振器，其中，限定所述第二声阻抗不匹配结构的上表面的所述桥结构的下表面设置有上台阶部，和/或限定所述第二声阻抗不匹配结构的下表面的所述第一压电层的上表面设置有下台阶部。The resonator according to claim 5, wherein the lower surface of the bridge structure defining the upper surface of the second acoustic impedance mismatching structure is provided with an upper step portion, and/or defines that the second acoustic impedance does not The upper surface of the first piezoelectric layer of the lower surface of the matching structure is provided with a lower stepped portion.
  9. 根据权利要求8所述的谐振器，其中：The resonator of claim 8, wherein:
    所述上台阶部在水平方向上设置在所述第一声阻抗不匹配结构与声学镜的边界之间；或者The upper step portion is disposed between the boundary of the first acoustic impedance mismatching structure and the acoustic mirror in the horizontal direction; or
    所述下台阶部在水平方向上设置在底电极的非电极连接端的外侧。The lower step portion is disposed outside the non-electrode connection end of the bottom electrode in the horizontal direction.
  10. 根据权利要求9所述的谐振器，其中，在底电极的电极连接端，所述第一压电层的上表面在声学镜边界的外侧设置有另外的台阶部。The resonator according to claim 9, wherein, at the electrode connection end of the bottom electrode, the upper surface of the first piezoelectric layer is provided with an additional stepped portion outside the boundary of the acoustic mirror.
  11. 根据权利要求5所述的谐振器，其中：The resonator of claim 5, wherein:
    所述第二声阻抗不匹配结构的上表面由顶电极的电极连接端限定；或者the upper surface of the second acoustic impedance mismatching structure is defined by the electrode connection end of the top electrode; or
    所述谐振器还包括设置在顶电极下侧的凸起结构，在顶电极的电极连接端，所述凸起结构限定所述第二声阻抗不匹配结构的上表面。The resonator further includes a protruding structure disposed on the lower side of the top electrode, at the electrode connection end of the top electrode, the protruding structure defines an upper surface of the second acoustic impedance mismatching structure.
  12. 根据权利要求1所述的谐振器，其中，所述谐振器还包括沿有效区域设置凸起结构和/或凹陷结构。The resonator according to claim 1, wherein the resonator further comprises a convex structure and/or a concave structure arranged along the effective area.
  13. 根据权利要求1所述的谐振器，其中，在顶电极的非电极连接端，所述第二压电层上侧的至少一个膜层的端面与第二压电层的端面在水平方向上错开。The resonator according to claim 1, wherein at the non-electrode connection end of the top electrode, the end surface of at least one film layer on the upper side of the second piezoelectric layer is horizontally staggered from the end surface of the second piezoelectric layer .
  14. 一种体声波谐振器的制造方法，包括：A method of manufacturing a bulk acoustic wave resonator, comprising:
    步骤1：形成底电极以及覆盖底电极的第一压电层，所述底电极至少包括在谐振器的厚度方向上设置的第一电极层和第二电极层，所述第一电极层与第二电极层之间设置有空隙层，所述空隙层限定谐振器的声学镜；Step 1: forming a bottom electrode and a first piezoelectric layer covering the bottom electrode, the bottom electrode at least includes a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator, the first electrode layer and the second electrode layer A gap layer is arranged between the two electrode layers, and the gap layer defines an acoustic mirror of the resonator;
    步骤2：在第一压电层上形成图形化介质层，所述图形化介质层至少用于形成第一声阻抗不匹配结构；Step 2: forming a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer is at least used to form a first acoustic impedance mismatch structure;
    步骤3：形成图形化的第二压电层，所述第二压电层的中间部分覆盖第一压电层的上表面，边缘部分覆盖所述图形化介质层的上表面而形成悬翼结构；和Step 3: forming a patterned second piezoelectric layer, the middle part of the second piezoelectric layer covers the upper surface of the first piezoelectric layer, and the edge part covers the upper surface of the patterned dielectric layer to form a cantilever structure ;and
    步骤4：以金属层覆盖步骤3形成的结构，对该金属层图形化，图形化后的金属层包括顶电极。Step 4: covering the structure formed in step 3 with a metal layer, patterning the metal layer, and the patterned metal layer includes a top electrode.
  15. 根据权利要求14所述的方法，其中：The method of claim 14, wherein:
    所述图形化介质层为牺牲材料层；以及The patterned medium layer is a sacrificial material layer; and
    所述方法还包括步骤5：释放所述牺牲材料层，以悬翼结构的下表面与第一压电层的上表面之间限定所述第一声阻抗不匹配结构。The method further includes step 5: releasing the sacrificial material layer to define the first acoustic impedance mismatch structure between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer.
  16. 根据权利要求15所述的方法，其中：The method of claim 15, wherein:
    在步骤2中，所述图形化介质层包括用于形成所述第一声阻抗不匹配结构的第一牺牲材料层，以及用于形成第二声阻抗不匹配结构的第二牺牲材料层，在顶电极的电极连接端，所述第一牺牲材料层与所述第二牺牲材料层彼此相接；以及In step 2, the patterned medium layer includes a first sacrificial material layer for forming the first acoustic impedance mismatch structure, and a second sacrificial material layer for forming the second acoustic impedance mismatch structure, an electrode connection end of the top electrode, the first sacrificial material layer and the second sacrificial material layer are in contact with each other; and
    在步骤5中，还包括释放所述第二牺牲材料层以形成所述第二声阻抗不匹配结构。In step 5, releasing the second sacrificial material layer to form the second acoustic impedance mismatching structure is also included.
  17. 根据权利要求14-16中任一项所述的方法，其中，所述第一声阻抗不匹配结构的内端用于限定谐振器的有效区域的边界。A method according to any one of claims 14-16, wherein the inner end of the first acoustic impedance mismatch structure is used to delimit the active area of the resonator.
  18. 一种滤波器，包括根据权利要求1-13中任一项所述的体声波谐振器。A filter comprising the bulk acoustic wave resonator according to any one of claims 1-13.
  19. 一种电子设备，包括根据权利要求18所述的滤波器，或者根据权利要求1-13中任一项所述的体声波谐振器。An electronic device, comprising the filter according to claim 18, or the bulk acoustic wave resonator according to any one of claims 1-13.
PCT/CN2022/111528 2021-08-10 2022-08-10 Bulk acoustic resonator having two piezoelectric layers, filter, and electronic device WO2023016500A1 (en)

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