WO2024021844A1 - 体声波谐振器及其制造方法、滤波器及电子设备 - Google Patents

体声波谐振器及其制造方法、滤波器及电子设备 Download PDF

Info

Publication number
WO2024021844A1
WO2024021844A1 PCT/CN2023/097313 CN2023097313W WO2024021844A1 WO 2024021844 A1 WO2024021844 A1 WO 2024021844A1 CN 2023097313 W CN2023097313 W CN 2023097313W WO 2024021844 A1 WO2024021844 A1 WO 2024021844A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
resonator
electrode
piezoelectric layer
electrode layer
Prior art date
Application number
PCT/CN2023/097313
Other languages
English (en)
French (fr)
Inventor
黄源清
张巍
郝龙
蒋兴勇
季艳丽
马晓丹
郑志强
张兰月
Original Assignee
诺思(天津)微系统有限责任公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 诺思(天津)微系统有限责任公司 filed Critical 诺思(天津)微系统有限责任公司
Publication of WO2024021844A1 publication Critical patent/WO2024021844A1/zh

Links

Classifications

    • 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
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02047—Treatment of substrates
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders; Supports
    • 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
    • H03H9/0504—Holders; Supports for bulk acoustic wave devices
    • H03H9/0514—Holders; Supports for bulk acoustic wave devices consisting of mounting pads or bumps
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/56—Monolithic crystal filters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/56—Monolithic crystal filters
    • H03H9/564—Monolithic crystal filters implemented with thin-film techniques
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • H03H9/582—Multiple crystal filters implemented with thin-film techniques
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type

Definitions

  • 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 having the resonator, and an electronic device.
  • FBAR Film Bulk Acoustic Resonator
  • BAW Bulk Acoustic Resonator
  • SAW surface acoustic wave
  • the main structure of the thin 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 metal electrode layers.
  • FBAR uses the inverse piezoelectric effect to convert the input electrical signal into mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output.
  • FIG. 1 shows a schematic cross-sectional view of a known bulk acoustic wave resonator.
  • the resonator includes a substrate 10, an acoustic mirror 20, a bottom electrode 30, a piezoelectric layer 40, a top electrode 50, an acoustic impedance mismatch structure 60, and passivation. layer or process layer 70. As shown in FIG.
  • the acoustic impedance mismatch structure 60 may be embodied as one or more of a gap layer 601 , a convex result 602 , a recessed structure 603 , and the like.
  • a gap layer 601 a convex result 602 , a recessed structure 603 , and the like.
  • a bulk acoustic wave resonator including:
  • the bottom electrode includes a first electrode layer and a second electrode layer.
  • a gap layer is provided between the first electrode layer and the second electrode layer.
  • the gap layer defines an acoustic mirror of the resonator.
  • the second electrode layer A portion of is located above the void layer;
  • the upper surface of the second electrode layer is formed with a protruding structure and/or a recessed structure along the effective area of the resonator.
  • the piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer, the second piezoelectric layer is located on the upper side of the first piezoelectric layer, and the end of the second piezoelectric layer is along the resonator.
  • the effective area is formed with a cantilever structure, and a first acoustic impedance mismatch structure is defined between a lower surface of the cantilever structure and an upper surface of the first piezoelectric layer.
  • the bulk acoustic wave resonator includes a substrate, an acoustic mirror, a bottom electrode, a top electrode and a device disposed between the bottom electrode and the top electrode.
  • the piezoelectric layer the method includes:
  • Step 1 Form a bottom electrode on the substrate.
  • the bottom electrode includes a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator. A gap is provided between the first electrode layer and the second electrode layer. a layer, the interstitial layer defining an acoustic mirror of the resonator, a portion of the second electrode layer being located above the interstitial layer;
  • Step 2 forming a recessed structure and/or a protruding structure at a predetermined position on the upper surface of the second electrode layer;
  • Step 3 forming a piezoelectric layer covering the upper surface of the second electrode layer
  • Step 4 Form the top electrode covering the piezoelectric layer.
  • Embodiments of the present invention also relate to a filter, including the above-mentioned bulk acoustic wave resonator or the resonator manufactured by the above-mentioned method.
  • Embodiments of the present invention also relate to an electronic device, including the above-mentioned filter or resonator or Resonator manufactured by the above method.
  • Figure 1 is a schematic cross-sectional view of a known bulk acoustic wave resonator. The cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator;
  • Figure 2 is a schematic cross-sectional view of a comparative example of the bulk acoustic wave resonator of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator;
  • 3A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, wherein the upper surface of the bottom electrode resonates along the
  • the effective area of the device is provided with a convex structure, and the piezoelectric layer is a double piezoelectric layer;
  • 3B is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, wherein the upper surface of the bottom electrode is along the
  • the effective area of the resonator is provided with a protruding structure, and the piezoelectric layer is a single piezoelectric layer;
  • Figure 4 is an exemplary comparison diagram of the parallel impedance Rp of the bulk acoustic wave resonator with the structure shown in Figure 3A and the bulk acoustic wave resonator shown in Figure 2;
  • FIG. 5A is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, wherein the upper surface of the bottom electrode is along the
  • the effective area of the resonator is provided with a recessed structure;
  • Figure 5B is an exemplary comparison diagram of the normalized Q average value near the series resonance point of the bulk acoustic wave resonator with the structure shown in Figure 5A and the bulk acoustic wave resonator shown in Figure 2;
  • FIG. 6 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, which is shown in FIG. 5A Structurally, a protruding structure is added to the upper surface of the upper piezoelectric layer;
  • FIG. 7 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, wherein the upper surface of the bottom electrode is along the
  • the effective area of the resonator is provided with a recessed structure;
  • FIG. 8 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention.
  • the cross-section passes through the electrode connection end of the top electrode and the electrode connection end of the bottom electrode of the resonator, wherein the bottom electrode
  • the upper surface of the electrode is provided with a recessed structure along the effective area of the resonator;
  • 9A-9K are schematic cross-sectional views of the manufacturing process of the resonator shown in FIG. 3A according to an exemplary embodiment of the present invention.
  • Substrate, optional materials are single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
  • Acoustic mirror which can be a cavity or a Bragg reflection layer or other equivalent forms. In an embodiment according to the present invention, it is a gap layer disposed in the bottom electrode.
  • the sacrificial layer used to form the acoustic mirror cavity, its material can be AlN, SiN, SiO 2 , etc.
  • Bottom electrode (including electrode pins), the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or their alloys, etc.
  • bottom electrode layer (including electrode pins), the material of bottom electrode layer 30B can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a combination of the above metals or other Alloy, etc., the material of the bottom electrode layer 30A only needs to be a conductor, for example, it can be a metal, alloy or compound conductor.
  • Piezoelectric layer which can be a single crystal piezoelectric material, optional, such as: single crystal aluminum nitride, single crystal gallium nitride, single crystal lithium niobate, single crystal lead zirconate titanate (PZT), single crystal Crystal potassium niobate, single crystal quartz film, or single crystal lithium tantalate and other materials; it can also be polycrystalline piezoelectric materials (corresponding to single crystal, non-single crystal materials), optional, such as polycrystalline aluminum nitride , zinc oxide, PZT, etc., or can also be a rare earth element doped material containing a certain atomic ratio of the above materials, for example, it can be doped aluminum nitride, and the 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), ne
  • the materials of the first piezoelectric layer and the second piezoelectric layer may be the same or different.
  • the material of the first piezoelectric layer or the second piezoelectric layer can be a single crystal piezoelectric material, optionally, such as: single crystal aluminum nitride, single crystal gallium nitride, single crystal lithium niobate, single crystal zirconate titanate Lead (PZT), single crystal potassium niobate, single crystal quartz film, or single crystal lithium tantalate and other materials; it can also be polycrystalline piezoelectric material (corresponding to single crystal, non-single crystal material), optional, Such as polycrystalline aluminum nitride, zinc oxide, PZT, etc., or rare earth element doped materials containing a certain atomic ratio of the above materials, for example, it can be doped aluminum nitride, and the doped aluminum nitride contains at least one rare earth element, Such
  • Top electrode (including electrode pins), the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the above metals or their alloys, etc.
  • the top and bottom electrode materials are generally the same, but can also be different.
  • the sacrificial layer used to form the sacrificial layer of the acoustic impedance mismatch structure, its material can be AlN, SiN, SiO 2 , etc.
  • 601A The void layer defined by the cantilever structure, as a specific form of acoustic impedance mismatch structure.
  • 601B The void layer defined by the bridge structure, as a specific form of acoustic impedance mismatch structure.
  • Raised structure as a specific form of acoustic impedance mismatch structure, its materials can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals Or its alloys, etc.
  • Recessed structure as a form of acoustic impedance mismatch structure Recessed structure as a form of acoustic impedance mismatch structure.
  • the passivation layer or process layer is provided on the top electrode of the resonator.
  • the function of the process layer can be a mass adjustment load or a passivation layer.
  • Its material can be a dielectric material, such as silicon dioxide, aluminum nitride, nitride Silicon etc. In the present invention, the passivation layer or the process layer may not be provided.
  • seed layer or barrier layer optional materials such as aluminum nitride, zinc oxide, PZT and rare earth element doping materials containing a certain atomic ratio of the above materials.
  • the seed layer S defines the upper boundary of the acoustic mirror 20 to reduce the negative impact of the sacrificial layer on the crystallographic orientation of the structure above it.
  • the seed layer or the barrier layer S may not be provided.
  • the edge based on the seed layer S is in the effective area on the outside, which can effectively reduce or even isolate the negative impact of the sacrificial layer on the crystallographic direction of the structure above it.
  • the seed layer or barrier layer S may not be provided.
  • FIG. 2 shows a schematic cross-sectional view of a reference example of the bulk acoustic wave resonator of the present invention.
  • the resonator includes a substrate 10, an acoustic mirror 20, a bottom electrode 30, a piezoelectric layer 40, a top electrode 50, and an acoustic impedance mismatch structure 601A. and 601B, passivation layer or process layer 70.
  • the bottom electrode includes bottom electrode layers 30A and 30B.
  • a gap layer serving as an acoustic mirror 20 is provided between them.
  • a seed layer or barrier layer S is provided on the upper side of the acoustic mirror 20.
  • the material of the seed layer can be It is AlN, SiN, etc.; the piezoelectric layer 40 includes a first piezoelectric layer 40A and a second piezoelectric layer 40B.
  • the end of the second piezoelectric layer 40B is formed with a cantilever structure or gap layer 601 along the effective area of the resonator.
  • the bottom electrode includes bottom electrode layers 30A and 30B, the resistance loss of the bottom electrode is reduced, thereby increasing the parallel impedance Rp of the resonator while also reducing the series impedance Rs of the resonator.
  • FIG. 3A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.
  • a resonator according to an exemplary embodiment of the present invention includes:
  • the bottom electrode includes a first electrode layer 30A and a second electrode layer 30B.
  • a gap layer is provided between the first electrode layer 30A and the second electrode layer 30B.
  • the gap layer defines the acoustic mirror 20, A part of the second electrode layer 30B is located above the acoustic mirror 20, and a protruding structure 101 is formed on the upper surface of the second electrode layer 30B along the effective area of the resonator;
  • the piezoelectric layer 40 includes a first piezoelectric layer 40A and a second piezoelectric layer 40B.
  • the second piezoelectric layer 40B is on the upper side of the first piezoelectric layer 40A
  • the second piezoelectric layer 40B is located on the upper side of the first piezoelectric layer 40A.
  • the end of the piezoelectric layer 40B is formed with a cantilever structure along the effective area of the resonator.
  • a first acoustic impedance mismatch structure is defined between the lower surface of the cantilever structure and the upper surface of the first piezoelectric layer 40A.
  • the acoustic impedance mismatch structure is composed of air, it can be seen that along the effective area of the resonator, the gap layer 601A is provided between the second piezoelectric layer 40B and the first piezoelectric layer 40A. Specifically, the first acoustic impedance mismatching structure is formed of air.
  • the impedance mismatch structure is the void layer 601A defined by the cantilever structure;
  • the process layer or passivation layer 70 may not be provided in the embodiment shown in FIG. 3A .
  • the bottom electrode may not only be two layers of electrodes, but may also be more electrode layers. In any case, the bottom electrode may be formed on the upper surface of the uppermost electrode layer (whether directly The protruding structure 101 is formed based on conduction during the deposition process.
  • the bottom electrode when the bottom electrode is a multi-layer electrode, not only can the parallel impedance of the resonator be improved by arranging the protruding structure 101 based on the upper surface of the bottom electrode, but also the parallel impedance of the bottom electrode can be reduced. Resistive losses reduce the series impedance of the resonator.
  • the filter manufactured using the resonator of the present invention can increase the insertion loss of the overall passband.
  • the first acoustic impedance mismatch structure or gap layer 601A can be provided along the entire effective area of the resonator or only along a part of the area, both of which are within the scope of the present invention.
  • the inner boundary of the void layer 601A is inboard of the boundary of the acoustic mirror 20, thereby defining the boundary of the active area of the resonator.
  • the inner boundary of the gap layer 601A may only define part of the boundary of the effective area or not define the boundary of the effective area, which are also within the scope of the present invention.
  • the end surface of the film layer on the upper side of the second piezoelectric layer 40B is flush with the end surface of the second piezoelectric layer 40B, but the invention is not limited thereto.
  • the end surface of at least one film layer on the upper side of the second piezoelectric layer 40B can also be offset from the end surface of the second piezoelectric layer 40B in the horizontal direction.
  • the second piezoelectric layer 40B The end surfaces of the upper film layers may all be located inside the end surfaces of the second piezoelectric layer 40B. In an optional embodiment, the end surfaces of at least one film layer on the upper side may also be located inside the end surfaces of the second piezoelectric layer 40B. outside.
  • the resonator is also provided with a barrier layer or seed layer S.
  • the barrier layer or seed layer S can play a role in protecting the electrode layer 30B when releasing or etching the later-mentioned sacrificial layer for the acoustic mirror.
  • the barrier layer or the seed layer S may not be provided.
  • the gap layer 601A in Figure 3A its upper surface may be directly defined by the lower surface of the electrode connection end of the top electrode; optionally, in another embodiment, although not shown, on the lower side of the top electrode of the resonator
  • the upper surface of the gap layer 601 can be directly defined by the lower surface of the protruding structure, which is also within the protection scope of the present invention.
  • a cantilever structure is provided at the non-electrode connection end of the top electrode 50, and a gap layer 601A is provided below the cantilever structure; at the electrode connection end of the top electrode 50, the resonator forms a bridge structure, An additional gap layer 601B is formed between the lower surface of the bridge structure and the upper surface of the first piezoelectric layer 40A (as an example, corresponding to the second acoustic impedance mismatching structure in the claims). As shown in FIG. 3A , at the electrode connection end of the top electrode, the gap layer 601A below the cantilever structure and the gap layer 601B below the bridge structure are connected to each other.
  • the upper surface of the protruding structure 101 is a flat surface.
  • the upper surface of the protruding structure 101 may be a stepped surface, which is more conducive to improving the parallel impedance Rp of the resonator.
  • the protruding structure 101 is provided on the upper surface of the gap electrode along the effective area of the resonator, the series impedance Rs of the resonator can be reduced while further increasing the parallel impedance of the resonator, thereby The performance of the resonator at the series and parallel frequency points can be improved to improve the insertion loss performance of the overall passband of the filter formed using the above resonator.
  • Figure 4 is an exemplary comparison diagram of the parallel impedance Rp of the bulk acoustic wave resonator with the structure shown in Figure 3A and the bulk acoustic wave resonator shown in Figure 2, where the parallel impedance Rp of the resonator shown in Figure 2 is defined as 1, then The parallel impedance of the resonator shown in Figure 3A is 1.6, which means that the parallel impedance of the resonator shown in Figure 3A is increased by 60% compared with the resonator of Figure 2.
  • the double-layer piezoelectric layer in Figure 3A can also be in the form of a single layer.
  • the other structures are consistent with Figure 3A and will not be described again here.
  • the parallel impedance of the resonator shown in Figure 1 is defined as 1, Then the parallel impedance of the resonator shown in Figure 3B is similar to 1.6, which means that the parallel impedance of the resonator shown in Figure 3B is increased by 60% compared with the resonator in Figure 1.
  • the film layer above the bottom electrode is also provided with protrusions at corresponding positions.
  • the film layers above the bottom electrode may not be provided with protrusions at corresponding positions, which is also within the scope of the present invention.
  • the upper surface of the bottom electrode is provided with protruding structures 101 along the effective area of the resonator.
  • the upper surface of the bottom electrode is provided with protruding structures 101 along the effective area of the resonator.
  • the recessed structure 102 is shown in Figure 5A.
  • Figure 5A as shown, when the upper surface of the bottom electrode is provided with a recessed structure 102 along the effective area of the resonator, the film layer above the bottom electrode is also provided with recesses at corresponding positions. However, if It is understood that one or more of the film layers above the bottom electrode Each of the corresponding positions may not be provided with depressions, which is also within the protection scope of the present invention.
  • the structure shown in Figure 5A is the same as the structure shown in Figure 3A, except that the recessed structure 102 in Figure 5A and the film layer on it are also provided with recesses, which is different from the convex structure 101 in Figure 3A and the film layer on it is also provided with recesses.
  • the structure shown in Figure 5A is the same or similar to the structure shown in Figure 3A in other aspects, and will not be described again here. Based on the structure shown in FIG. 5A , by arranging the recessed structure 102 on the upper surface of the bottom electrode, the parasitic modes below the series resonance frequency fs of the resonator can be weakened.
  • FIG. 5B is an exemplary comparison diagram of the normalized Q average value near the series resonance point of the bulk acoustic wave resonator with the structure shown in FIG. 5A and the bulk acoustic wave resonator shown in FIG. 2 , in which the series resonance shown in FIG. 2 is The average value of Q near the point is defined as 1, then the average value of Q near the series resonance point of the resonator shown in Figure 5A is about 1.45, which means that the average value of Q near the series resonance point of the resonator shown in Figure 5A is larger than that shown in Figure 5A 2's resonator is improved by about 45%.
  • the double-layer piezoelectric layer in the structure shown in Figure 5A can also be in the form of a single-layer piezoelectric layer.
  • the other structures are consistent with those in Figure 5A and will not be discussed here.
  • the technical effects obtained are similar to those obtained by the structure shown in Figure 5A, so they will not be described again here.
  • the resonator further includes a protruding structure 604 disposed on the lower side of the top electrode 50 at the non-electrode connection end and the electrode connection end of the top electrode. Except for the additional protrusion structure 604, the structure shown in Figure 6 is similar to the structure shown in Figure 5A, and will not be described again here.
  • the outer end of the convex structure 101 or the recessed structure 102 in the above embodiments and method steps is outside the inner end of the gap layer 601A.
  • the outer end of the convex structure 101 or the recessed structure 102 is offset or flush with the outer end of the gap layer 601A or the second piezoelectric layer 40B in the horizontal direction.
  • FIG. 7 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, in which the outer end of the recessed structure 102 is flush with the outer end of the gap layer 601A in the horizontal direction.
  • FIG. 8 is a schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present invention, in which the outer end of the recessed structure 102 and the outer end of the gap layer 601A are staggered in the horizontal direction. As shown in FIG. 8 , the recessed structure The outer end of 102 is located outside the outer end of the gap layer 601A in the horizontal direction.
  • the recessed structures 102 in Figures 7 and 8 can also be convex structures 101.
  • the outer end of the recessed structure 102 is not provided with a boss, but the outer end of the recessed structure 102 may also be provided with a boss 41 , as shown in FIGS. 7 and 8 .
  • boss 41 you can A discontinuous point of the stacked structure is formed outside the main resonator area of the resonator, thereby reflecting the leaked sound waves back to the main resonator area to further enhance the Q value.
  • the upper surface of the bottom electrode may also be provided with both a recessed structure and a protruding structure. Compared with separately arranging a recessed structure or a convex structure, it is beneficial to improve the parallel resonance impedance of the resonator and weaken the parasitic modes below the series resonance frequency fs of the resonator.
  • a substrate 10 is provided.
  • a metal layer for forming the bottom electrode layer 30A is deposited on the substrate 10 .
  • an acoustic mirror sacrificial material layer is deposited and patterned on the metal layer shown in FIG. 9B to form a sacrificial layer 21 (that is, taking the acoustic mirror as a cavity as an example).
  • a seed layer S is deposited and patterned on the upper surface of the structure shown in Figure 9C.
  • a metal layer for forming the bottom electrode layer 30B is deposited on the upper surface of the structure shown in FIG. 9D , and the two metal layers are patterned to form the bottom electrode.
  • the material of the bottom electrode layer 30B and the bottom electrode layer 30A may be the same. In a further optional embodiment, the materials of the bottom electrode layer 30B and the bottom electrode layer 30A may be different.
  • the acoustic impedance of the bottom electrode layer 30B in FIG. 9E may be higher than that of the bottom electrode layer 30A. In FIG. 9E , the acoustic impedance of the bottom electrode layer 30B may be higher than that of the bottom electrode layer 30A.
  • the conductivity of bottom electrode layer 30A is higher than the conductivity of bottom electrode layer 30B.
  • a depression is formed in the middle position of the upper surface of the bottom electrode layer 30B to form a protruding structure 101 at the edge position of the bottom electrode layer 30B along the effective area.
  • a predetermined thickness of the electrode material layer is removed to form the protruding structure 101 .
  • the recessed structure 102 may be formed along the edge of the effective area on the upper surface of the bottom electrode layer 30B.
  • the recessed structure 102 may be formed on the upper surface of the bottom electrode layer 30B along the edge of the resonator.
  • a predetermined thickness of the electrode material layer is removed from a portion of the effective area to form the recessed structure 102 .
  • the removal here may use any process suitable for removing a predetermined thickness of the electrode material layer, such as etching or trimming using particle beam bombardment.
  • a first piezoelectric layer 40A is deposited. It can be seen that conduction also forms bumps above the bump structure of the bottom electrode.
  • a sacrificial material layer is deposited and patterned on the upper surface of the first piezoelectric layer 40A (here, the acoustic impedance mismatch structure 601 is a cavity as an example, but if It can be understood that the acoustic impedance mismatch structure can be directly a dielectric layer without release) to form the acoustic impedance mismatch structure sacrificial layer 61.
  • a second piezoelectric layer 40B is deposited and patterned to form the structure shown in FIG. 9I .
  • the top electrode 50 and the process layer 70 are formed by sequential deposition and patterning.
  • the acoustic mirror sacrificial material layer 21 in Figure 9J is released to form the acoustic mirror 20, and the acoustic impedance mismatch structure sacrificial layer 61 is released to form the acoustic impedance mismatch structure 601, thereby obtaining the resonator shown in Figure 3A structure.
  • the protruding structure 101 and the recessed structure 102 are formed on the upper surface of the bottom electrode layer 30B along the edge positions of the expected effective area.
  • the present invention proposes a method for manufacturing a bulk acoustic wave resonator.
  • the bulk acoustic wave resonator includes a substrate 10, an acoustic mirror 20, a bottom electrode 30, a top electrode 50 and a pressure electrode disposed between the bottom electrode and the top electrode.
  • Electrical layer 40 the method includes:
  • Step 1 Form a bottom electrode 30 on the substrate 10.
  • the bottom electrode 30 includes a first electrode layer 30A and a second electrode layer 30B arranged in the thickness direction of the resonator.
  • the first electrode layer 30A and the second electrode A void layer is provided between the layers 30B, the void layer defining the acoustic mirror 20 of the resonator, and a portion of the second electrode layer 30B is located above the void layer;
  • Step 2 Form a recessed structure and/or a protruding structure at a predetermined position on the upper surface of the second electrode layer 30B;
  • Step 3 Form the piezoelectric layer 40 covering the upper surface of the second electrode layer
  • Step 4 Form the top electrode 50 covering the piezoelectric layer 40.
  • the height of the protruding structure 101 or the depth of the recessed structure 102 in the above embodiments and method steps is within the range, optional, in within the scope of, further optional, in In the range.
  • the inner end of the protruding structure 101 or the concave structure 102 in the above embodiments and method steps is located inside the inner end of the acoustic impedance mismatching structure 601 .
  • all The distance in the horizontal direction between the inner end of the convex structure 101 or the recessed structure 102 and the inner end of the acoustic impedance mismatching structure 601 is no more than 20 ⁇ m, and further optionally, no more than 5 ⁇ m.
  • each numerical range except that it is clearly stated that it does not include the endpoint value, can be the endpoint value or the median value of each numerical range, which are all within the protection scope of the present invention. .
  • upper and lower are relative to the bottom surface of the base of the resonator.
  • the side close to the bottom surface is the lower side, and the side far away from the bottom surface is the upper side.
  • inside and outside are relative to the center of the effective area of the resonator (the overlapping area of the piezoelectric layer, top electrode, bottom electrode and 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 close to the center is the inside or inner end
  • the side or end of the component away from the center is the outside or outer end.
  • being inside the position means being between the position and the center in the horizontal or radial direction
  • being outside the position means being farther away from the position than the position in the horizontal or radial direction. center.
  • the bulk acoustic wave resonator according to the present invention may be used to form filters or electronic devices.
  • the electronic equipment here includes but is not limited to intermediate products such as radio frequency front-ends and filter amplification modules, as well as terminal products such as mobile phones, WIFI, and drones.
  • a bulk acoustic wave resonator including:
  • the bottom electrode includes a first electrode layer and a second electrode layer.
  • a gap layer is provided between the first electrode layer and the second electrode layer.
  • the gap layer defines an acoustic mirror of the resonator.
  • the second electrode layer A portion of is located above the void layer;
  • the upper surface of the second electrode layer is formed with a protruding structure and/or a recessed structure along the effective area of the resonator.
  • the height of the protruding structure or the depth of the concave structure is the height of the protruding structure or the depth of the concave structure.
  • the height of the protruding structure or the depth of the concave structure is In the range.
  • the height of the protruding structure or the depth of the concave structure is In the range.
  • the piezoelectric layer includes a first piezoelectric layer and a second piezoelectric layer.
  • the second piezoelectric layer is located on the upper side of the first piezoelectric layer, and an end of the second piezoelectric layer is formed along the effective area of the resonator.
  • a cantilever structure, a first acoustic impedance mismatch structure is defined between a lower surface of the cantilever structure and an upper surface of the first piezoelectric layer.
  • the inner end of the convex structure or the recessed structure is located inside the inner end of the first acoustic impedance mismatching structure.
  • the distance in the horizontal direction between the inner end of the convex structure or the recessed structure and the inner end of the first acoustic impedance mismatching structure is not greater than 20 ⁇ m.
  • the distance in the horizontal direction between the inner end of the convex structure or the recessed structure and the inner end of the first acoustic impedance mismatching structure is not greater than 5 ⁇ m.
  • the outer end of the convex structure or the recessed structure is outside the inner end of the first acoustic impedance mismatching structure.
  • the outer end of the convex structure or the recessed structure is staggered or flush with the outer end of the first acoustic impedance mismatching structure in the horizontal direction.
  • the resonator forms a bridge structure, and the lower part of the bridge structure A second acoustic impedance mismatch structure is formed between the surface and the upper surface of the first piezoelectric layer, and the first acoustic impedance mismatch structure and the second acoustic impedance mismatch structure are connected to each other.
  • the top surface of the convex structure is a flat surface, or the bottom surface of the recessed structure is a flat surface; or
  • the top surface of the convex structure is a stepped surface, or the bottom surface of the recessed structure is a stepped surface; or
  • the bottom electrode has a boss at an outer end of the recessed structure.
  • a protrusion structure is formed on the upper surface of the second electrode layer along the effective area of the resonator, and a corresponding protrusion is formed on the film layer above the second electrode layer above the protrusion structure;
  • a recessed structure is formed on the upper surface of the second electrode layer along the effective area of the resonator, and a corresponding recess is formed in the film layer above the second electrode layer above the recessed structure.
  • the cantilever structure is arranged around the entire effective area.
  • the inner boundary of the first acoustic impedance mismatch structure defines the boundary of the active area.
  • a method of manufacturing a bulk acoustic wave resonator which includes a substrate, an acoustic mirror, a bottom electrode, a top electrode, and a piezoelectric layer disposed between the bottom electrode and the top electrode. The method includes:
  • Step 1 Form a bottom electrode on the substrate.
  • the bottom electrode includes a first electrode layer and a second electrode layer arranged in the thickness direction of the resonator. A gap is provided between the first electrode layer and the second electrode layer. a layer, the interstitial layer defining an acoustic mirror of the resonator, a portion of the second electrode layer being located above the interstitial layer;
  • Step 2 forming a recessed structure and/or a protruding structure at a predetermined position on the upper surface of the second electrode layer;
  • Step 3 forming a piezoelectric layer covering the upper surface of the second electrode layer
  • Step 4 Form the top electrode covering the piezoelectric layer.
  • the step 3 includes:
  • Step 31 Form a first piezoelectric layer covering the upper surface of the second electrode layer
  • Step 32 Form a patterned dielectric layer on the first piezoelectric layer, the patterned dielectric layer being at least used to form a first acoustic impedance mismatch structure;
  • Step 33 Form 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 the structure formed in step 33 is covered with a metal layer, and the metal layer is patterned.
  • 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.
  • step 2 in the middle part of the upper surface of the second electrode layer, remove a predetermined thickness of the electrode material layer to form the protruding structure;
  • step 2 remove a predetermined thickness of the electrode material layer from a portion of the upper surface of the second electrode layer along the effective area of the resonator to form the recessed structure;
  • step 2 a recessed structure or a protruding structure is formed at a predetermined position on the upper surface of the second electrode layer through a trimming process.
  • the inner end of the first acoustic impedance mismatch structure serves to define the boundaries of the active area of the resonator.
  • a filter comprising the bulk acoustic wave resonator according to any one of 1-15 or the bulk acoustic wave resonator manufactured according to the method according to any one of 16-20.
  • An electronic device including the filter according to 21, or the bulk acoustic wave resonator according to any one of 1-15, or the bulk acoustic wave resonance manufactured according to the method according to any one of 16-20 device.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

本发明涉及一种体声波谐振器及其制造方法，所述谐振器包括基底；底电极；声学镜；顶电极；和压电层，其中：所述底电极包括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，所述第二电极层的一部分位于所述空隙层的上方；且所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构和/或凹陷结构。本发明还涉及一种滤波器及一种电子设备。

Description

体声波谐振器及其制造方法、滤波器及电子设备 技术领域
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。
背景技术
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。
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。
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。
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隙层或介质层。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10、声学镜20、底电极30、压电层40、顶电极50、声阻抗不匹配结构60、钝化层或工艺层70。如图1所示，声阻抗不匹配结构60可以体现为空隙层601、凸起结果602和凹陷结构603等中的一个或多个。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。
发明内容
为解决上述技术问题的至少一个方面，提出本发明。
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，
其中：
所述底电极包括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，所述第二电极层的一部分位于所述空隙层的上方；且
所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构和/或凹陷结构。
可选的，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。
根据本发明的实施例的还一方面，提出了一种体声波谐振器的制造方法，所述体声波谐振器包括基底、声学镜、底电极、顶电极和设置在底电极与顶电极之间的压电层，所述方法包括：
步骤1：在基底上形成底电极，所述底电极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，第二电极层的一部分位于所述空隙层的上方；
步骤2：在第二电极层的上表面的预定位置形成凹陷结构和/或凸起结构；
步骤3：形成覆盖第二电极层的上表面的压电层；
步骤4：形成覆盖压电层的顶电极。
本发明的实施例也涉及一种滤波器，包括上述体声波谐振器或者上述方法制造的谐振器。
本发明的实施例还涉及一种电子设备，包括上述的滤波器或者谐振器或者 上述方法制造的谐振器。
附图说明
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：
图1为已知的一种体声波谐振器的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端；
图2为本发明的体声波谐振器的一个对比示例的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端；
图3A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，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其中底电极的上表面沿谐振器的有效区域设置有凸起结构，且压电层为双层压电层；
图3B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，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其中底电极的上表面沿谐振器的有效区域设置有凸起结构，且压电层为单层压电层；
图4为图3A中所示结构的体声波谐振器与图2所示的体声波谐振器的并联阻抗Rp的示例性比较图；
图5A为根据本发明的还一个示例性实施例的体声波谐振器的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其中底电极的上表面沿谐振器的有效区域设置有凹陷结构；
图5B为图5A中所示结构的体声波谐振器与图2所示的体声波谐振器的串联谐振点附近Q平均值归一化的示例性比较图；
图6为根据本发明的再一个示例性实施例的体声波谐振器的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其在图5A所示的结构上在上压电层的上表面增加了凸起结构；
图7为根据本发明的还一个示例性实施例的体声波谐振器的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其中底电极的上表面沿谐振器的有效区域设置有凹陷结构；
图8为根据本发明的又一个示例性实施例的体声波谐振器的截面示意图，该截面通过了谐振器的顶电极的电极连接端以及底电极的电极连接端，其中底 电极的上表面沿谐振器的有效区域设置有凹陷结构；
图9A-图9K为根据本发明的一个示例性实施例的关于图3A所示的谐振器的制作过程的截面示意图。
具体实施方式
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。
首先，在本发明中，附图标记示例性说明如下：
10: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。
20：声学镜，可为空腔，也可采用布拉格反射层及其他等效形式。在根据本发明的实施例中，其为设置于底电极中的空隙层。
21：用于形成声学镜空腔的牺牲层，其材料可以是AlN、SiN、SiO2等。
30：底电极(包括电极引脚)，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。
30A和30B：底电极层(包括电极引脚)，底电极层30B的材料可选钼，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30A的材料为导电体即可，例如可以为金属、合金或化合物导体等。
40：压电层，其可以为单晶压电材料，可选的，如：单晶氮化铝、单晶氮化镓、单晶铌酸锂、单晶锆钛酸铅(PZT)、单晶铌酸钾、单晶石英薄膜、或者单晶钽酸锂等材料；也可以为多晶压电材料(与单晶相对应，非单晶材料)，可选的，如多晶氮化铝、氧化锌、PZT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。
40A和40B：分别为第一压电层与第二压电层，第一压电层与第二压电层的材料可以相同，也可以不同。第一压电层或第二压电层的材料可以为单晶压电材料，可选的，如：单晶氮化铝、单晶氮化镓、单晶铌酸锂、单晶锆钛酸铅(PZT)、单晶铌酸钾、单晶石英薄膜、或者单晶钽酸锂等材料；也可以为多晶压电材料(与单晶相对应，非单晶材料)，可选的，如多晶氮化铝、氧化锌、PZT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。
50：顶电极(包括电极引脚)，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。顶电极和底电极材料一般相同，但也可以不同。
60：声阻抗不匹配结构。
61：用于形成声阻抗不匹配结构牺牲层的牺牲层，其材料可以是AlN、SiN、SiO2等。
601A：悬翼结构限定的空隙层，作为声阻抗不匹配结构的一种具体形式。
601B：桥结构限定的空隙层，作为声阻抗不匹配结构的一种具体形式。
602和604：凸起结构，作为声阻抗不匹配结构的一种具体形式，其材料可选钼，钌，金，铝，镁，钨，铜，钛，铱，锇，铬或以上金属的复合或其合金等。
603：凹陷结构，作为声阻抗不匹配结构中的一种形式。
70：钝化层或工艺层，设置在谐振器的顶电极上，工艺层的作用可以是质量调节负载或钝化层，其材料可以为介质材料，如二氧化硅、氮化铝、氮化硅等。在本发明中，也可以不设置钝化层或工艺层。
101：凸起结构，沿谐振器的有效区域形成在底电极的上表面。
102：凹陷结构，沿谐振器的有效区域形成在底电极的上表面。
S：种子层或阻挡层，可选氮化铝，氧化锌，PZT等材料并包含上述材料的一定原子比的稀土元素掺杂材料。在本发明中，种子层S限定声学镜20的上边界，以降低牺牲层对其上方的结构的晶向的不利影响。在本发明中，也可以不设置种子层或阻挡层S。在图示的实施例中，基于种子层S的边缘处于有效区域 的外侧，可有效减少甚至隔绝牺牲层对其上方结构的晶向的不利影响。也可以不设置种子层或阻挡层S。
图2示出了本发明的体声波谐振器的一个参考示例的截面示意图，该谐振器包括基底10、声学镜20、底电极30、压电层40、顶电极50、声阻抗不匹配结构601A和601B、钝化层或工艺层70。如图2所示，底电极包括底电极层30A和30B，两者之间设置有作为声学镜20的间隙层，声学镜20的上侧设置有种子层或阻挡层S，种子层的材料可以为AlN、SiN等；压电层40包括第一压电层40A和第二压电层40B，第二压电层40B的端部沿谐振器的有效区域形成有悬翼结构或空隙层601。基于图2的结构，因为底电极包括了底电极层30A和30B，所以降低了底电极的电阻损耗，从而在提升谐振器并联阻抗Rp的同时也降低了谐振器的串联阻抗Rs。虽然图2所示的结构相对于图1所示结构有利于提升谐振器在串联和并联频率点处的性能，但是，还存在进一步提升谐振器在串联和并联频率点处的性能的需求从而进一步提升滤波器整体通带的插损表现的需求。
下面参照图3A-图9K示例性说明本发明的具体实施例。
图3A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3A所示，根据本发明的示例性实施例的谐振器包括：
基底10；
声学镜20；
底电极30，所述底电极包括第一电极层30A和第二电极层30B，第一电极层30A与第二电极层30B之间设置有空隙层，所述空隙层限定所述声学镜20，所述第二电极层30B的一部分位于所述声学镜20的上方，第二电极层30B的上表面沿谐振器的有效区域形成有凸起结构101；
压电层40，所述压电层包括第一压电层40A和第二压电层40B，在图3中，第二压电层40B处于第一压电层40A的上侧，且第二压电层40B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40A的上表面之间限定有第一声阻抗不匹配结构，在该声阻抗不匹配结构为空气构成的情况下，可以看到，沿谐振器的有效区域，空隙层601A设置在第二压电层40B与第一压电层40A之间，具体的第一声阻抗不匹配结构为悬翼结构限定的空隙层601A；
顶电极50；和
工艺层或钝化层70，在图3A所示的实施例中，如能够理解的，也可以不设置工艺层或钝化层70。
在图3A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，不论怎样，在最上层的电极层的上表面形成(不论是直接形成还是基于在沉积过程中的传导形成)有凸起结构101。对于图3所示结构的谐振器，在底电极为多层电极的情况下，不仅可以通过基于底电极的上表面设置凸起结构101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。
在图3A所示的结构中，第一声阻抗不匹配结构或空隙层601A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。
在本发明的一个实施例中，例如参见图3A，空隙层601A的内侧边界处于声学镜20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，空隙层601A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。
在图3A中，在顶电极的非电极连接端，第二压电层40B上侧的膜层的端面与第二压电层40B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40B上侧的至少一个膜层的端面也可以与第二压电层40B的端面在水平方向上错开，具体的，第二压电层40B上侧的膜层的端面可以均处于第二压电层40B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40B的端面的外侧。
可选的，在图3A所示结构中，谐振器还设置有阻挡层或种子层S。在电极层30B例如为含铝的金属层的情况下，该阻挡层或种子层S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电极层30B的作用。但是，如前提及的，也可以不设置阻挡层或种子层S。
对于图3A中的空隙层601A，其上表面可以直接由顶电极的电极连接端的下表面限定；可选的，在另外的实施例中，虽然没有示出，在谐振器的顶电极的下侧设置有凸起结构的情况下，空隙层601的上表面可以直接由该凸起结构的下表面限定，这也在本发明的保护范围之内。
如图3A所示，在顶电极50的非电极连接端设置有悬翼结构，悬翼结构的下方设置有空隙层601A；在顶电极50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第一压电层40A的上表面之间形成有另外的空隙层601B(作为示例，对应于权利要求中的第二声阻抗不匹配结构)。在如图3A所示，在顶电极的电极连接端，悬翼结构的下方的空隙层601A与桥结构下方的空隙层601B彼此相接。
如图3A所示，凸起结构101的上表面为平坦面。可选的，虽然没有示出，凸起结构101的上表面可以为阶梯面，这更有利于提高谐振器的并联阻抗Rp。
在图3A所示的结构中，因为在间隙电极的上表面沿谐振器的有效区域设置有凸起结构101，可以在降低谐振器的串联阻抗Rs的同时，进一步提升谐振器的并联阻抗，从而可以提升谐振器在串联和并联频率点处的性能，以在利用上述谐振器形成的滤波器中提升滤波器整体通带的插损表现。图4为图3A中所示结构的体声波谐振器与图2所示的体声波谐振器的并联阻抗Rp的示例性比较图，其中将图2所示的谐振器并联阻抗定义为1，则如图3A所示的谐振器的并联阻抗为1.6，这意味着图3A所示的谐振器的并联阻抗较图2的谐振器提升了60％。
如图3B所示，在本发明的一个实施例中，图3A中的双层压电层也可以为单层形式，其他结构与图3A一致，这里不再赘述。对于图3B所示的结构，因为存在凸起结构101，可以相对于图1所示的结构具有更大的并联阻抗，类似于图4，将图1所示的谐振器并联阻抗定义为1，则将图3B所示的谐振器的并联阻抗类似的为1.6，这意味着图3B所示的谐振器的并联阻抗较图1的谐振器提升了60％。
如图3A和图3B所示，在底电极的上表面沿谐振器的有效区域设置有凸起结构101的情况下，底电极上方的膜层在对应位置也相应设置有凸起，不过，如能够理解的，底电极上方的膜层中的一个或多个在对应位置也可以不设置有凸起，这也在本发明的保护范围之内。
在图3A和图3B所示的结构中，底电极的上表面沿谐振器的有效区域设置有凸起结构101，但是本发明不限于此，底电极的上表面沿谐振器的有效区域设置有凹陷结构102，如图5A所示。在图5A中，如所示的，在底电极的上表面沿谐振器的有效区域设置有凹陷结构102的情况下，底电极上方的膜层在对应位置也相应设置有凹陷，不过，如能够理解的，底电极上方的膜层中的一个或多 个在对应位置也可以不设置有凹陷，这也在本发明的保护范围之内。
图5A所示的结构与图3A所示结构，除了图5A中设置凹陷结构102以及其上的膜层也设置有凹陷不同于图3A中设置凸起结构101以及其上的膜层也设置有凸起，图5A所示的结构与图3A所示结构其他方面相同或相似，这里不再赘述。基于图5A所示的结构，通过在底电极的上表面设置凹陷结构102，可以削弱谐振器的串联谐振频率fs以下的寄生模式。
图5B为图5A中所示结构的体声波谐振器与图2所示的体声波谐振器的串联谐振点附近Q平均值归一化的示例性比较图，其中将图2所示的串联谐振点附近Q平均值定义为1，则如图5A所示的谐振器的串联谐振点附近Q平均值为1.45左右，这意味着图5A所示的谐振器的串联谐振点附近Q平均值较图2的谐振器提升了约45％。
虽然没有示出，在本发明的一个实施例中，图5A所示的结构中的双层压电层也可以为单层压电层的形式，其他结构与图5A中的一致，这里不再赘述，而且其获得的技术效果也与图5A所示结构所获得的技术效果类似，这里也不再赘述。
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另外的凸起结构，图6中示出了这样的一个示例性结构。在图6中，谐振器在顶电极的非电极连接端和电极连接端还包括设置在顶电极50下侧的凸起结构604。除了另外设置凸起结构604之外，图6所示结构与图5A所示结构相似，这里不再赘述。
在本发明的一个实施例中，上述实施例以及方法步骤中的所述凸起结构101或凹陷结构102的外端处于空隙层601A的内端的外侧。在进一步可选的实施例中，所述凸起结构101或凹陷结构102的外端与空隙层601A或者第二压电层40B的外端在水平方向上错开或者齐平。图7为根据本发明的还一个示例性实施例的体声波谐振器的截面示意图，其中凹陷结构102的外端与空隙层601A的外端在水平方向上齐平。图8为根据本发明的又一个示例性实施例的体声波谐振器的截面示意图，其中凹陷结构102的外端与空隙层601A的外端在水平方向上错开，如图8所示，凹陷结构102的外端在水平方向处于空隙层601A的外端的外侧。图7和图8中的凹陷结构102也可以为凸起结构101。
在图3A、3B以及图5A-图6所示的实施例中，凹陷结构102的外端并未设置凸台，但是其外端也可以设置凸台41，如图7和图8所示。采用凸台41，可 以在谐振器的主谐振器区域以外形成一个叠层结构的不连续点，从而对泄露的声波反射回主谐振器区域，以进一步提升Q值。
虽然没有示出，底电极的上表面也可以同时设置有凹陷结构和凸起结构。相较于单独设置凹陷结构或凸起结构，有利于提升谐振器的并联谐振阻抗以及削弱谐振器的串联谐振频率fs以下的寄生模式。
下面参照图9A-图9K示例性说明图3A所示的谐振器的制作过程。
如图9A所示，提供基底10。
如图9B所示，在基底10上沉积用于形成底电极层30A的金属层。
如图9C所示，在图9B所示的金属层上沉积并图形化声学镜牺牲材料层而形成牺牲层21(即以声学镜为空腔为例)。
如图9D所示，在图9C所示结构的上表面沉积和图形化种子层S。
如图9E所示，在图9D所示结构的上表面沉积用于形成底电极层30B的金属层，对两个金属层图形化以形成底电极。底电极层30B和底电极层30A的材料可以相同。在进一步可选的实施例中，底电极层30B和底电极层30A的材料可以不同，可以是图9E中的底电极层30B的声阻抗高于底电极层30A的声阻抗，图9E中的底电极层30A的导电率高于底电极层30B的导电率。
如图9F所示，在图9E所示结构上，在底电极层30B的上表面的中间位置形成凹陷从而在底电极层30B的沿有效区域的边缘位置形成凸起结构101，具体的，在底电极层30B的上表面的中间部分，移除预设厚度的电极材料层以形成所述凸起结构101。虽然没有示出，对于图5A所示的结构，可以是在底电极层30B的上表面的沿有效区域的边缘位置形成凹陷结构102，具体的，在底电极层30B的上表面的沿谐振器的有效区域的部分，移除预设厚度的电极材料层以形成所述凹陷结构102。这里的移除可以采用任何适于将预设厚度的电极材料层移除的工艺，例如刻蚀或者利用粒子束轰击的修整工艺(trim)。
如图9G所示，在图9F所示结构的基础上，沉积第一压电层40A。可以看到，在底电极的凸起结构的上方也传导而形成有凸起。
如图9H所示，在图9G所示结构的基础上，在第一压电层40A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601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61。
如图9I所示，在图9H所示结构的基础上，沉积和图形化第二压电层40B，以形成如图9I所示的结构。
如图9J所示，在图9H所示结构的基础上依次沉积和图形化而形成顶电极50和工艺层70。
如图9K所示，释放图9J中的声学镜牺牲材料层21以形成声学镜20，释放声阻抗不匹配结构牺牲层61以形成声阻抗不匹配结构601，从而得到图3A所示的谐振器结构。
如能够理解的，图5A-图8所示结构均可以采用与上述相似的步骤制得，对于图3B所示的结构，则可以将图9G-图9I对应的步骤变更为直接形成单层压电层的步骤。
对于如上提及的在底电极的上表面同时设置有凹陷结构和凸起结构，则可以在上述图9F对应的步骤中，在图9E所示结构上，经由刻蚀工艺或修整工艺或剥离工艺等，在底电极层30B的上表面沿预期的有效区域的边缘位置形成凸起结构101和凹陷结构102。
基于以上，本发明提出了一种体声波谐振器的制造方法，所述体声波谐振器包括基底10、声学镜20、底电极30、顶电极50和设置在底电极与顶电极之间的压电层40，所述方法包括：
步骤1：在基底10上形成底电极30，所述底电极30包括在谐振器的厚度方向上设置的第一电极层30A和第二电极层30B，所述第一电极层30A与第二电极层30B之间设置有空隙层，所述空隙层限定谐振器的声学镜20，第二电极层30B的一部分位于所述空隙层的上方；
步骤2：在第二电极层30B的上表面的预定位置形成凹陷结构和/或凸起结构；
步骤3：形成覆盖第二电极层的上表面的压电层40；
步骤4：形成覆盖压电层40的顶电极50。在本发明的一个实施例中，上述实施例以及方法步骤中的凸起结构101的高度或者凹陷结构102的深度在的范围内，可选的，在的范围内，进一步可选的，在的范围内。
在本发明的一个实施例中，上述实施例以及方法步骤中的所述凸起结构101或凹陷结构102的内端处于声阻抗不匹配结构601的内端的内侧。可选的，所 述凸起结构101或凹陷结构102的内端与所述声阻抗不匹配结构601的内端在水平方向上的距离不大于20μm，进一步可选的，不大于5μm。
需要指出的是，在本发明中，各个数值范围，除了明确指出不包含端点值之外，除了可以为端点值，还可以为各个数值范围的中值，这些均在本发明的保护范围之内。
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。
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)在水平方向或者径向方向上而言的，一个部件的靠近该中心的一侧或一端为内侧或内端，而该部件的远离该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水平方向或径向方向上处于该位置与该中心之间，位于该位置的外侧表示在水平方向或径向方向上比该位置更远离该中心。
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。
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。
基于以上，本发明提出了如下技术方案：
1、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，
其中：
所述底电极包括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，所述第二电极层的一部分位于所述空隙层的上方；且
所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构和/或凹陷结构。
2、根据1所述的谐振器，其中：
所述凸起结构的高度或者所述凹陷结构的深度在
的范围内。
3、根据2所述的谐振器，其中：
所述凸起结构的高度或者所述凹陷结构的深度在的范围内。
4、根据3所述的谐振器，其中：
所述凸起结构的高度或者所述凹陷结构的深度在的范围内。
5、根据1所述的谐振器，其中：
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。
6、根据5所述的谐振器，其中：
所述凸起结构或凹陷结构的内端处于所述第一声阻抗不匹配结构的内端的内侧。
7、根据6所述的谐振器，其中：
所述凸起结构或凹陷结构的内端与所述第一声阻抗不匹配结构的内端在水平方向上的距离不大于20μm。
8、根据7所述的谐振器，其中：
所述凸起结构或凹陷结构的内端与所述第一声阻抗不匹配结构的内端在水平方向上的距离不大于5μm。
9、根据5所述的谐振器，其中：
所述凸起结构或凹陷结构的外端处于所述第一声阻抗不匹配结构的内端的外侧。
10、根据9所述的谐振器，其中：
所述凸起结构或凹陷结构的外端与所述第一声阻抗不匹配结构的外端在水平方向上错开或者齐平。
11、根据5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。
12、根据1所述的谐振器，其中：
所述凸起结构的顶面为平坦面，或所述凹陷结构的底面为平坦面；或者
所述凸起结构的顶面为阶梯面，或所述凹陷结构的底面为阶梯面；或者
所述底电极在所述凹陷结构的外端具有凸台。
13、根据1所述的谐振器，其中：
所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构，且所述第二电极层上方的膜层在在所述凸起结构上方位置形成有对应凸起；或者
所述第二电极层的上表面沿谐振器的有效区域形成有凹陷结构，且所述第二电极层上方的膜层在在所述凹陷结构上方位置形成有对应凹陷。
14、根据1-13中任一项所述的谐振器，其中：
所述悬翼结构围绕整个所述有效区域设置。
15、根据14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。
16、一种体声波谐振器的制造方法，所述体声波谐振器包括基底、声学镜、底电极、顶电极和设置在底电极与顶电极之间的压电层，所述方法包括：
步骤1：在基底上形成底电极，所述底电极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，第二电极层的一部分位于所述空隙层的上方；
步骤2：在第二电极层的上表面的预定位置形成凹陷结构和/或凸起结构；
步骤3：形成覆盖第二电极层的上表面的压电层；
步骤4：形成覆盖压电层的顶电极。
17、根据16所述的方法，其中：
所述步骤3包括：
步骤31：形成覆盖第二电极层的上表面的第一压电层；
步骤32：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33：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；
且其中：
所述步骤4中，以金属层覆盖步骤33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。
18、根据17所述的方法，其中：
所述图形化介质层为牺牲材料层；
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。
19、根据17所述的方法，其中：
在步骤2中，在第二电极层的上表面的中间部分，移除预设厚度的电极材料层以形成所述凸起结构；或者
在步骤2中，在第二电极层的上表面的沿谐振器的有效区域的部分，移除预设厚度的电极材料层以形成所述凹陷结构；或者
在步骤2中，以修整工艺在第二电极层的上表面的预定位置形成凹陷结构或凸起结构。
20、根据17-19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。
21、一种滤波器，包括根据1-15中任一项所述的体声波谐振器或者根据16-20中任一项所述的方法制造的体声波谐振器。
22、一种电子设备，包括根据21所述的滤波器，或者根据1-15中任一项所述的体声波谐振器或者根据16-20中任一项所述的方法制造的体声波谐振器。
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。

Claims (22)

  1. 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，
    其中：
    所述底电极包括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，所述第二电极层的一部分位于所述空隙层的上方；且
    所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构和/或凹陷结构。
  2. 根据权利要求1所述的谐振器，其中：
    所述凸起结构的高度或者所述凹陷结构的深度在的范围内。
  3. 根据权利要求2所述的谐振器，其中：
    所述凸起结构的高度或者所述凹陷结构的深度在的范围内。
  4. 根据权利要求3所述的谐振器，其中：
    所述凸起结构的高度或者所述凹陷结构的深度在的范围内。
  5. 根据权利要求1所述的谐振器，其中：
    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。
  6. 根据权利要求5所述的谐振器，其中：
    所述凸起结构或凹陷结构的内端处于所述第一声阻抗不匹配结构的内端的内侧。
  7. 根据权利要求6所述的谐振器，其中：
    所述凸起结构或凹陷结构的内端与所述第一声阻抗不匹配结构的内端在水平方向上的距离不大于20μm。
  8. 根据权利要求7所述的谐振器，其中：
    所述凸起结构或凹陷结构的内端与所述第一声阻抗不匹配结构的内端在水平方向上的距离不大于5μm。
  9. 根据权利要求5所述的谐振器，其中：
    所述凸起结构或凹陷结构的外端处于所述第一声阻抗不匹配结构的内端的外侧。
  10. 根据权利要求9所述的谐振器，其中：
    所述凸起结构或凹陷结构的外端与所述第一声阻抗不匹配结构的外端在水平方向上错开或者齐平。
  11. 根据权利要求5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。
  12. 根据权利要求1所述的谐振器，其中：
    所述凸起结构的顶面为平坦面，或所述凹陷结构的底面为平坦面；或者
    所述凸起结构的顶面为阶梯面，或所述凹陷结构的底面为阶梯面；或者
    所述底电极在所述凹陷结构的外端具有凸台。
  13. 根据权利要求1所述的谐振器，其中：
    所述第二电极层的上表面沿谐振器的有效区域形成有凸起结构，且所述第二电极层上方的膜层在所述凸起结构上方位置形成有对应凸起；或者
    所述第二电极层的上表面沿谐振器的有效区域形成有凹陷结构， 且所述第二电极层上方的膜层在在所述凹陷结构上方位置形成有对应凹陷。
  14. 根据权利要求1-13中任一项所述的谐振器，其中：
    所述悬翼结构围绕整个所述有效区域设置。
  15. 根据权利要求14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。
  16. 一种体声波谐振器的制造方法，所述体声波谐振器包括基底、声学镜、底电极、顶电极和设置在底电极与顶电极之间的压电层，所述方法包括：
    步骤1：在基底上形成底电极，所述底电极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，第二电极层的一部分位于所述空隙层的上方；
    步骤2：在第二电极层的上表面的预定位置形成凹陷结构和/或凸起结构；
    步骤3：形成覆盖第二电极层的上表面的压电层；
    步骤4：形成覆盖压电层的顶电极。
  17. 根据权利要求16所述的方法，其中：
    所述步骤3包括：
    步骤31：形成覆盖第二电极层的上表面的第一压电层；
    步骤32：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33：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；
    且其中：
    所述步骤4中，以金属层覆盖步骤33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。
  18. 根据权利要求17所述的方法，其中：
    所述图形化介质层为牺牲材料层；
    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。
  19. 根据权利要求17所述的方法，其中：
    在步骤2中，在第二电极层的上表面的中间部分，移除预设厚度的电极材料层以形成所述凸起结构；或者
    在步骤2中，在第二电极层的上表面的沿谐振器的有效区域的部分，移除预设厚度的电极材料层以形成所述凹陷结构；或者
    在步骤2中，以修整工艺在第二电极层的上表面的预定位置形成凹陷结构或凸起结构。
  20. 根据权利要求17-19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。
  21. 一种滤波器，包括根据权利要求1-15中任一项所述的体声波谐振器或者根据权利要求16-20中任一项所述的方法制造的体声波谐振器。
  22. 一种电子设备，包括根据权利要求21所述的滤波器，或者根据权利要求1-15中任一项所述的体声波谐振器，或者根据权利要求16-20中任一项所述的方法制造的体声波谐振器。
PCT/CN2023/097313 2022-07-28 2023-05-31 体声波谐振器及其制造方法、滤波器及电子设备 WO2024021844A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210899268.8 2022-07-28
CN202210899268.8A CN117478094A (zh) 2022-07-28 2022-07-28 体声波谐振器及其制造方法、滤波器及电子设备

Publications (1)

Publication Number Publication Date
WO2024021844A1 true WO2024021844A1 (zh) 2024-02-01

Family

ID=89638455

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/097313 WO2024021844A1 (zh) 2022-07-28 2023-05-31 体声波谐振器及其制造方法、滤波器及电子设备

Country Status (2)

Country Link
CN (1) CN117478094A (zh)
WO (1) WO2024021844A1 (zh)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070008050A1 (en) * 2005-07-05 2007-01-11 Samsung Electronics Co., Ltd. Bulk acoustic resonator including a resonance part with dimple and fabrication method therefor
CN111082777A (zh) * 2019-12-31 2020-04-28 诺思(天津)微系统有限责任公司 底电极为空隙电极的体声波谐振器、滤波器及电子设备
CN111245394A (zh) * 2019-12-16 2020-06-05 诺思(天津)微系统有限责任公司 电极具有空隙层与温补层的体声波谐振器、滤波器及电子设备
CN114070248A (zh) * 2020-08-06 2022-02-18 诺思(天津)微系统有限责任公司 带声学解耦层的体声波谐振器组件及制造方法、滤波器及电子设备
CN114070224A (zh) * 2020-08-06 2022-02-18 诺思(天津)微系统有限责任公司 带声学解耦层的体声波谐振器组件及制造方法、滤波器及电子设备
CN114696774A (zh) * 2020-12-31 2022-07-01 诺思(天津)微系统有限责任公司 单晶体声波谐振器、滤波器及电子设备
CN115765675A (zh) * 2021-09-03 2023-03-07 诺思(天津)微系统有限责任公司 包括间隙电极的体声波谐振器、滤波器及电子设备

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070008050A1 (en) * 2005-07-05 2007-01-11 Samsung Electronics Co., Ltd. Bulk acoustic resonator including a resonance part with dimple and fabrication method therefor
CN111245394A (zh) * 2019-12-16 2020-06-05 诺思(天津)微系统有限责任公司 电极具有空隙层与温补层的体声波谐振器、滤波器及电子设备
CN111082777A (zh) * 2019-12-31 2020-04-28 诺思(天津)微系统有限责任公司 底电极为空隙电极的体声波谐振器、滤波器及电子设备
CN114070248A (zh) * 2020-08-06 2022-02-18 诺思(天津)微系统有限责任公司 带声学解耦层的体声波谐振器组件及制造方法、滤波器及电子设备
CN114070224A (zh) * 2020-08-06 2022-02-18 诺思(天津)微系统有限责任公司 带声学解耦层的体声波谐振器组件及制造方法、滤波器及电子设备
CN114696774A (zh) * 2020-12-31 2022-07-01 诺思(天津)微系统有限责任公司 单晶体声波谐振器、滤波器及电子设备
CN115765675A (zh) * 2021-09-03 2023-03-07 诺思(天津)微系统有限责任公司 包括间隙电极的体声波谐振器、滤波器及电子设备

Also Published As

Publication number Publication date
CN117478094A (zh) 2024-01-30

Similar Documents

Publication Publication Date Title
WO2021077712A1 (zh) 电极具有空隙层的体声波谐振器、滤波器及电子设备
WO2021109444A1 (zh) 体声波谐振器及其制造方法、滤波器及电子设备
WO2021042741A1 (zh) 压电层具有插入结构的体声波谐振器、滤波器和电子设备
JP2007335977A (ja) 電子素子
JP2003505906A (ja) 共振子構造およびその共振子構造を備えるフィルタ
CN113497594A (zh) 单晶体声波谐振器及其制造方法、滤波器及电子设备
WO2021077716A1 (zh) 体声波谐振器、滤波器及电子设备
WO2022028402A1 (zh) 带声学解耦层的体声波谐振器组件及制造方法、滤波器及电子设备
WO2022083352A1 (zh) 体声波谐振器及组件、滤波器、电子设备
WO2021114555A1 (zh) 电极具有空隙层的体声波谐振器、滤波器及电子设备
WO2022143286A1 (zh) 单晶体声波谐振器、滤波器及电子设备
WO2022148387A1 (zh) 体声波谐振器及其制造方法、滤波器及电子设备
WO2020134803A1 (zh) 电极厚度不对称的体声波谐振器、滤波器和电子设备
WO2022228385A1 (zh) 具有加厚电极的体声波谐振器、滤波器及电子设备
WO2022037572A1 (zh) 顶电极具有上下空隙的体声波谐振器及制造方法、滤波器及电子设备
WO2022228384A1 (zh) 体声波谐振器、滤波器及电子设备
WO2023030359A1 (zh) 包括间隙电极的体声波谐振器、滤波器及电子设备
WO2022218376A1 (zh) 压电层下侧设置凸起和/或凹陷的体声波谐振器、滤波器及电子设备
WO2024087628A1 (zh) 选择凸起结构的角度以提升性能的体声波谐振器
CN114553169A (zh) 利用凸起结构降低声阻抗的体声波谐振器、滤波器及电子设备
WO2022135252A1 (zh) 带温补层的体声波谐振器、滤波器及电子设备
WO2024021844A1 (zh) 体声波谐振器及其制造方法、滤波器及电子设备
WO2022188777A1 (zh) 体声波谐振器及其制造方法、滤波器及电子设备
WO2023016500A1 (zh) 具有双压电层的体声波谐振器、滤波器及电子设备
WO2024021933A1 (zh) 压电层下侧设置凸起或凹陷的体声波谐振器及制造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23845057

Country of ref document: EP

Kind code of ref document: A1