WO2022012438A1 - Résonateur acoustique de volume à couches et son procédé de fabrication - Google Patents

Résonateur acoustique de volume à couches et son procédé de fabrication Download PDF

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Publication number
WO2022012438A1
WO2022012438A1 PCT/CN2021/105531 CN2021105531W WO2022012438A1 WO 2022012438 A1 WO2022012438 A1 WO 2022012438A1 CN 2021105531 W CN2021105531 W CN 2021105531W WO 2022012438 A1 WO2022012438 A1 WO 2022012438A1
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layer
electrode
sacrificial layer
gap
forming
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PCT/CN2021/105531
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English (en)
Chinese (zh)
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黄河
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中芯集成电路（宁波）有限公司
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Publication of WO2022012438A1 publication Critical patent/WO2022012438A1/fr

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02086—Means for compensation or elimination of undesirable effects
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • H03H9/131—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials consisting of a multilayered structure
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
    • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/173—Air-gaps
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
    • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/174—Membranes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H03H2003/028—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks for obtaining desired values of other parameters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H2009/02165—Tuning
    • H03H2009/02173—Tuning of film bulk acoustic resonators [FBAR]

Definitions

  • the invention relates to the field of semiconductor device manufacturing, in particular to a thin-film bulk acoustic wave resonator and a manufacturing method thereof.
  • RF front-end modules have gradually become the core components of communication equipment.
  • filters have become the most rapidly growing and most promising components.
  • the performance of the filter is determined by the resonator units that make up the filter.
  • FBARs thin-film bulk acoustic resonators
  • FBARs thin-film bulk acoustic resonators
  • a thin-film bulk acoustic wave resonator includes two thin-film electrodes, and a piezoelectric thin-film layer is arranged between the two thin-film electrodes.
  • the bulk acoustic wave propagating in the thickness direction of the electric film layer is transmitted to the interface between the upper and lower electrodes and the air and is reflected back, and then reflected back and forth inside the film to form an oscillation.
  • Standing wave oscillations are formed when a sound wave propagates in a piezoelectric film layer that is exactly an odd multiple of a half-wavelength.
  • the quality factor (Q) of the cavity-type thin-film bulk acoustic wave resonators produced at present cannot be further improved, so it cannot meet the needs of high-performance radio frequency systems.
  • the purpose of the present invention is to provide a thin film bulk acoustic wave resonator and a manufacturing method thereof, which can solve the problem that the quality factor of the thin film bulk acoustic wave resonator is not high.
  • the present invention provides a thin film bulk acoustic resonator, comprising: a stacked first electrode, a piezoelectric layer and a second electrode, and the effective resonance region includes the first electrode, the piezoelectric layer and the second electrode in the The overlapping regions in the direction perpendicular to the surface of the piezoelectric layer, the outside of the effective resonance region is an inactive region; the first dielectric layer, the upper surface of the first dielectric layer and the lower surface of the first electrode are between the upper surface and the lower surface of the first electrode.
  • a first gap is set between them; a second dielectric layer, a second gap is set between the lower surface of the second dielectric layer and the upper surface of the second electrode;
  • the lower surface of an electrode is connected with the first electrode lead-out portion at the other end;
  • the second conductive protrusion is arranged on the upper surface of the second electrode at one end, and the second electrode lead-out portion is connected at the other end.
  • the present invention also provides a method for manufacturing a thin film bulk acoustic resonator, comprising: forming a first structure, the first structure comprising: a first electrode, a first sacrificial layer covering at least the first electrode, at least on the The side of the first sacrificial layer surrounds the dielectric layer of the first sacrificial layer; a first conductive bump is formed, which penetrates through the first sacrificial layer and is connected to the first electrode at one end; a first conductive bump, the other end of which extends out of the effective resonance area; a piezoelectric layer is formed; a second structure is formed, the second structure includes: a second electrode, a second sacrificial layer covering at least the second electrode, A dielectric layer surrounding the second sacrificial layer at least on the side of the second sacrificial layer; forming a second conductive bump, penetrating the second sacrificial layer, and connecting one end to the second electrode; forming a second electrode
  • the beneficial effect of the present invention is that: in the bulk acoustic wave resonator of the present invention, the first electrode is connected to the external signal through the first conductive protrusion and the first electrode lead-out portion, and the first electrode is connected to the external signal through the second conductive protrusion and the second electrode lead-out portion.
  • the two electrodes are connected to external signals, which can increase the electrode lead-out area and impedance, while suppressing the coupling effect between electrodes and enhancing heat conduction;
  • the first gap and the second gap serve as acoustic wave reflection structures to improve the quality factor of the resonator;
  • the first conductive protrusion and The area where the second conductive protrusions are located forms an acoustic impedance mismatch area, which can make the boundary of the effective resonance area and the acoustic impedance inside the effective resonance area mismatch, which is beneficial to improve the quality factor of the resonator;
  • the first conductive protrusions The projection of the second conductive protrusion and the second conductive protrusion on the surface of the carrier substrate is a closed or discontinuous ring, which can further suppress the loss of transverse acoustic wave energy and improve the quality factor of the resonator.
  • the side edges of the first electrode and the second electrode are exposed in the gap, which can suppress the shear wave loss; further, the edge of the piezoelectric layer is exposed in the gap, which can further suppress the shear wave loss; further, the piezoelectric layer is A complete film layer can ensure the piezoelectric properties of the piezoelectric layer; in the manufacturing method of the bulk acoustic wave resonator of the present invention, the piezoelectric layer is formed on the flat electrode layer, which can make the piezoelectric layer have better lattice orientation , to improve the piezoelectric properties of the piezoelectric layer, thereby improving the overall performance of the resonator; further, the first electrode layer, the piezoelectric material layer, and the second electrode layer can be etched synchronously, saving process time; further, the first sacrifice The layer and the second sacrificial layer can be removed simultaneously or in steps, improving process flow flexibility.
  • FIG. 1 shows a schematic structural diagram of a thin film bulk acoustic wave resonator according to Embodiment 1 of the present invention.
  • FIG. 2 shows a schematic structural diagram of a thin film bulk acoustic wave resonator according to Embodiment 2 of the present invention.
  • FIG. 3 shows a schematic structural diagram of a thin film bulk acoustic wave resonator according to Embodiment 3 of the present invention.
  • FIG. 4 to FIG. 14 are schematic structural diagrams corresponding to different steps of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 4 of the present invention.
  • FIG. 15 to FIG. 21 are schematic structural diagrams corresponding to different steps of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 5 of the present invention.
  • FIG. 22 to FIG. 30 are schematic structural diagrams corresponding to different steps of a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 6 of the present invention.
  • 100-carrying substrate 101A-dielectric layer surrounding the first sacrificial layer at least on the side of the first sacrificial layer; 101B-first passivation layer; 101-first dielectric layer; 102A- 102B—the second passivation layer; 102—the second dielectric layer; 200—the temporary substrate; 201′—the first electrode layer; 201 202-piezoelectric layer; 203'-second electrode layer; 203-second electrode; 210-first sacrificial layer; 220-second sacrificial layer; 211-first gap; 221-second gap 301-first conductive bump; 302-second conductive bump; 303-first electrode lead-out; 304-second electrode lead-out; 10-first cavity; 212-release hole.
  • the cavity-type thin-film bulk acoustic wave resonator produced at present has the problem of shear wave loss, so that the quality factor (Q) cannot be further improved, so it cannot meet the needs of high-performance radio frequency systems.
  • Embodiment 1 of the present invention provides a thin-film bulk acoustic resonator.
  • FIG. 1 is a schematic structural diagram of the thin-film bulk acoustic resonator according to Embodiment 1 of the present invention. Please refer to FIG. 1.
  • the thin-film bulk acoustic resonator includes: from bottom to top It includes a first electrode 201 , a piezoelectric layer 202 and a second electrode 203 stacked in sequence, and the effective resonance region includes the first electrode 201 , the piezoelectric layer 202 and the second electrode 203 in a direction perpendicular to the surface of the piezoelectric layer 202
  • a first gap is set between the upper surface of the first dielectric layer 101 and the lower surface of the first electrode 201 211
  • the second dielectric layer 102 a second gap 221 is provided between the lower surface of the second dielectric layer 102 and the upper surface of the second electrode 202
  • the first conductive protrusion 301 one end is provided on The lower surface of the first electrode 201 is connected with the first electrode lead-out portion 303 at the other end
  • the second conductive protrusion 302 is arranged on the upper surface of the second electrode 202 at one end and connected with the second electrode lead-out portion at the other end
  • a carrier substrate 100 is further included.
  • the first dielectric layer 101 and the carrier substrate 100 may be combined by bonding layers or deposition.
  • the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.
  • the first dielectric layer 101 is formed on the carrier substrate 100 by means of deposition.
  • the first dielectric layer may have a single-layer structure or a stacked-layer structure.
  • the material of the first dielectric layer may include, but is not limited to, one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc., but the technology of the present invention is not limited to this.
  • the material of the carrier substrate 100 can be any suitable substrate known to those skilled in the art, for example, it can be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe) , silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III/V compound semiconductors.
  • the top of the first dielectric layer 101 includes a first electrode 201 , a piezoelectric layer 202 , and a second electrode 203 that are stacked in sequence from bottom to top.
  • the second electrode 202 and the first electrode 201 can use any suitable conductive material or semiconductor material known in the art, wherein the conductive material can be a metal material with conductive properties, such as molybdenum (Mo), aluminum (Al) ), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au) ), osmium (Os), rhenium (Re), palladium (Pd) and other metals, or a laminate of the above metals.
  • Mo molybdenum
  • Al aluminum
  • Cu copper
  • tantalum (Ta) platinum
  • Pt ruthen
  • the semiconductor material is, for example, Si, Ge, SiGe, SiC, SiGeC, or the like.
  • the piezoelectric layer 202 can be made of aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or tantalic acid Piezoelectric materials having a wurtzite crystal structure, such as lithium (LiTaO3), and combinations thereof.
  • the piezoelectric layer 202 may further include a rare earth metal such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La).
  • the piezoelectric layer 202 may further include a transition metal such as at least one of zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). kind.
  • the piezoelectric layer 202 may be deposited using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition.
  • the upper surface of the first dielectric layer 101 is concave in the middle and protruding at the outer periphery.
  • a first gap 211 is provided between the lower surface of the first electrode 201 and the upper surface of the recessed area of the first dielectric layer 101 .
  • the boundary of the first gap 211 is larger than the boundary of the first electrode 201 , so that the bottom surface of the piezoelectric layer 202 around the edge of the first electrode 201 is also exposed in the first gap 211 .
  • the piezoelectric layer 202 is a horizontally complete film layer, and the periphery extends to above the surface of the protruding area of the first dielectric layer 101 .
  • the edge of the first electrode 201 is completely exposed in the first gap 211, which can make the edge of the first electrode 201 and the air form a reflection interface, make the acoustic impedance mismatch, suppress the leakage of shear waves, and further improve the quality factor (Q value) of the resonator .
  • the second dielectric layer 102 is located above the first dielectric layer 101 .
  • the material of the second dielectric layer 102 may include, but is not limited to, one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, etc.
  • the second dielectric layer may have a single-layer structure or a stacked-layer structure . In this embodiment, the middle of the lower surface of the second dielectric layer 102 is concave, and the outer periphery is convex.
  • a second gap 221 is provided between the upper surface of the second electrode 203 and the lower surface of the recessed area of the second dielectric layer 102 .
  • the boundary of the second gap 221 is larger than the boundary of the second electrode 203 , so that the upper surface of the piezoelectric layer 202 around the edge of the second electrode 203 is exposed in the second gap 221 .
  • the edge of the second electrode 203 is completely exposed in the second gap 221, which can make the edge of the second electrode 203 and the air form a reflective interface, make the acoustic impedance mismatch, suppress the leakage of shear waves, and further improve the quality factor (Q value) of the resonator .
  • the recessed area and the second gap 221 of the second dielectric layer 102 are disposed opposite to the recessed area and the second gap 211 of the first dielectric layer 101 , and the protruding area of the second dielectric layer 102 is opposite to the first dielectric layer 101
  • the convex area of is set relatively.
  • the effective resonance region of the resonator includes a region where the first electrode 201 , the piezoelectric layer 202 and the second electrode 203 overlap each other in a direction perpendicular to the surface of the piezoelectric layer 202 .
  • the boundary of the projection of the first gap 211 and the second gap 221 in the direction of the piezoelectric layer 202 surrounds the boundary of the projection of the effective resonance region in the direction of the piezoelectric layer 202 .
  • “Enclosed” means that the boundary of the effective resonance region is within the first gap 211 and the second gap 221, or the boundary of the effective resonance region coincides with the boundary of the first gap and/or the second gap.
  • the situation shown in FIG. 1 is that the boundary of the effective resonance region is within the first gap 211 and the second gap 221 .
  • the boundary of the projection of the first gap 211 and the second gap 221 in the direction of the piezoelectric layer 202 surrounds the first electrode 201 and the second electrode 203 in the piezoelectric layer.
  • the boundary of the projection in the layer 202 direction is the same as that described above.
  • the first electrode is located in the area enclosed by the boundary of the first gap, or the boundaries of the two overlap; or, the second electrode is located in the area enclosed by the boundary of the second gap. area, or the boundaries of the two coincide.
  • the edge of the first electrode 201 extends beyond the region where the first gap 211 is located, and the edge of the second electrode 203 is located in the second gap 221; or the edge of the first electrode 201 is located in the first gap 211, and the edge of the second electrode 203 The edge extends out of the second gap 221 ; of course, a part of the edge of the first electrode 201 may also be in the first gap 211 , and another part of the edge extends out of the first gap 211 , or a part of the edge of the second electrode 203 is in the second gap 221 Inside, another part of the edge extends out of the second gap 221 .
  • the edges of the first electrode 201 and the second electrode 203 are both exposed in their respective gaps, the area of acoustic impedance mismatch can be increased, the shear wave leakage can be further suppressed, and the quality factor (Q value) of the resonator can be improved.
  • the piezoelectric layer 202 includes a resonance portion 2021 and a lap portion 2022 located on the outer periphery of the resonance portion.
  • the resonance portion 2021 is located in the effective resonance region, and the overlap portion 2022 is located in the effective resonance region. outside the resonance region.
  • the piezoelectric layer 202 is a complete film layer, and the resonance portion 2021 and the overlapping portion 2022 are integral structures.
  • the first gap 211 and the second gap 221 are isolated from each other by the piezoelectric layer 202 .
  • the first gap and the second gap may be communicated through a plurality of through holes distributed in the inactive region, for example, the through holes penetrate through the piezoelectric layer of the inactive region.
  • the inner wall of the annular through hole can form the boundary of the effective resonance area, and the inner wall of the annular through hole also may be located outside the boundaries of the effective resonant region.
  • a film layer is provided between the first gap and the second gap in the inactive region, and the film layer is a piezoelectric layer or a film layer of a material different from that of the piezoelectric layer; The piezoelectric layer is located only in the effective resonance region.
  • the lower surface of the first electrode 201 is provided with a first conductive bump 301 .
  • the first conductive bumps 301 may be single or multiple columns.
  • the first conductive protrusions 301 are disposed at the edge of the effective resonance region, and the projection on the surface direction of the piezoelectric layer 202 is a ring shape, wherein the ring shape includes a discontinuous or closed ring shape.
  • the shape of the ring can be a circle, an ellipse, a polygon, or an irregular shape composed of arcs and straight sides.
  • a closed loop means that the first conductive bumps 301 are continuous, and an open loop means that the first conductive bumps 301 are discontinuous.
  • the area where the first conductive protrusion 301 is located forms an acoustic impedance mismatch with the effective resonance area, so that the outwardly propagating transverse acoustic waves can be reflected back to the effective resonance area, so as to suppress the leakage of transverse clutter, reduce energy loss, and improve resonance
  • the quality factor (Q value) of the device When the projection of the first conductive protrusion 301 on the surface of the piezoelectric layer 302 is a closed ring shape, it is more beneficial to prevent the lateral leakage of sound waves.
  • the other end of the first conductive bump 301 is connected to the first electrode lead-out portion 303 .
  • the first electrode lead-out portion 303 is embedded in the first dielectric layer 101 .
  • the first electrode lead-out portion 303 may also be located on the upper surface of the recessed area of the first dielectric layer 101 .
  • the first electrode lead-out portion 303 is led out from the side where the effective resonance region is located to the outside.
  • the first electrode lead-out portion 303 can be used as a signal input terminal to introduce an electrical signal into the first electrode 201 in the effective resonance region, and can also be used as a signal output terminal to output the electrical signal on the first electrode 201 .
  • the upper surface of the second electrode 203 is provided with a second conductive bump 302 .
  • the second conductive bumps 302 may be single or multiple columns.
  • the second conductive protrusions 302 are arranged at the edge of the effective resonance region, and the projection on the surface direction of the piezoelectric layer 202 is a ring shape, wherein the ring shape includes a discontinuous or closed ring shape.
  • the shape of the ring can be a circle, an ellipse, a polygon, or an irregular shape composed of arcs and straight sides.
  • a closed loop means that the second conductive bumps 302 are continuous, and an open loop means that the second conductive bumps 302 are discontinuous.
  • the area where the second conductive protrusion 302 is located forms an acoustic impedance mismatch with the effective resonance area, so that the lateral acoustic waves propagating outward can be reflected back to the effective resonance area, so as to suppress the leakage of lateral clutter, reduce energy loss, and improve resonance
  • the quality factor (Q value) of the device When the projection of the second conductive protrusions 302 on the surface of the piezoelectric layer 302 is a closed ring shape, it is more beneficial to prevent the lateral leakage of sound waves.
  • the other end of the second conductive bump 302 is connected to the second electrode lead-out portion 304 .
  • the second electrode lead-out portion 304 is embedded in the second dielectric layer 102 .
  • the second electrode lead-out portion 304 may also be located on the lower surface of the recessed region of the second dielectric layer 101 . It can be seen from FIG. 1 that the second electrode lead-out portion 304 is drawn out from the side where the effective resonance region is located to the outside.
  • the second electrode lead-out portion 304 can be used as a signal input terminal to introduce an electrical signal into the second electrode 203 in the effective resonance region, and can also be used as a signal output terminal to output the electrical signal on the second electrode 203 .
  • the first electrode lead-out portion 303 serves as a signal input end
  • the second electrode lead-out portion 304 serves as a signal output end, and vice versa.
  • the projections of the first conductive bumps 301 and the second conductive bumps 302 in the direction of the piezoelectric layer 202 at least partially overlap.
  • the at least partial overlap includes: 1.
  • the projected shapes of the first conductive bump 301 and the second conductive bump 302 are the same, and the two completely overlap. 2.
  • the projected area of one of the first conductive bumps 301 and the second conductive bumps 302 is larger than that of the other projection, and the projection with a larger area covers the projection with a smaller area.
  • the shape trends of the two projections are roughly the same, and the overlapping parts of the two projections are continuous, or one projection and the other projection only have an overlapping part in a part of the area. This arrangement makes the acoustic impedance mismatch effect of the two conductive protrusions superimposed, effectively preventing the lateral leakage of the acoustic wave, and further improving the quality factor of the resonator.
  • the projection of one conductive protrusion in the direction of the surface of the piezoelectric layer is located at the outer circumference of the projection of the other conductive protrusion in the direction of the surface of the piezoelectric layer, such as when the two conductive protrusions are annular, wherein One ring surrounds the other ring.
  • the projections of the first electrode lead-out portion 303 and the second electrode lead-out portion 304 in the direction of the piezoelectric layer 202 are staggered from each other. Avoid high-frequency coupling due to potential floating, and prevent parasitic capacitance effects.
  • the projections of the first conductive bumps 301 and the second conductive bumps 302 on the surface direction of the piezoelectric layer together form a ring shape. It should be understood that when the projection of the first conductive protrusions 40a and/or the second protrusions 40b in the direction of the surface of the piezoelectric layer is a closed figure, it is more beneficial to prevent the lateral leakage of sound waves.
  • the material of the first conductive bump 301 or the second conductive bump 302 is a conductive material, such as gold, silver, tungsten, platinum, aluminum, copper and other materials with low resistivity.
  • the material of the first electrode lead-out portion 303 or the second electrode lead-out portion 304 can refer to the material of the first conductive bump 301 or the second conductive bump 302, and the material of the conductive bump can be the same or different from that of the electrode lead-out portion.
  • Embodiment 2 of the present invention provides a thin-film bulk acoustic resonator.
  • FIG. 2 is a schematic structural diagram of the thin-film bulk acoustic resonator of Embodiment 2 of the present invention.
  • the difference between this embodiment and Embodiment 1 is that in this embodiment, the pressure The resonance portion 2021 and the overlapping portion 2022 of the electrical layer 202 are separated from each other. Please refer to FIG.
  • the specific structure is as follows: the resonance portion 2021 and the overlapping portion 2022 of the piezoelectric layer 202 are separated from each other, the edge of the first electrode 201 is exposed in the first gap 211 , and the edge of the second electrode 203 is exposed in the second gap In 221, the first gap 211 and the second gap 221 communicate with each other to form an integral cavity, the resonance part 2021 is located in the cavity, the overlapping part 2022 is located outside the cavity, and the overlapping part 2022 and the resonance part 2021 are completely separated, The outer periphery of the resonance portion 2021 is all exposed in the cavity. As shown in FIG.
  • the edge of the resonance portion 2021 of the piezoelectric layer coincides with the edges of the first electrode 201 and the second electrode 203 to form the edge of the effective resonance region.
  • the resonance portion 2021 is all located in the effective resonance region. . .
  • the resonating part 2021 and the overlapping part 2022 have both parts connected to each other and parts separated from each other.
  • the edge of the resonant part 2021 exposed in the cavity forms a reflection interface with the air, which makes the acoustic impedance mismatch, suppresses the leakage of shear waves, and further improves the quality factor (Q value) of the resonator.
  • Embodiment 3 of the present invention provides a thin-film bulk acoustic resonator.
  • FIG. 3 is a schematic structural diagram of the thin-film bulk acoustic resonator according to Embodiment 3 of the present invention.
  • the difference between this embodiment and Embodiment 1 is that the first conductive protrusion 301 All of them are located at the edge of the first gap 211 and are in contact with the first dielectric layer 101 on the periphery.
  • a part of the second conductive bump 302 is located at the edge of the second gap 221 in contact with the second dielectric layer 102 , and a part is located in the second gap 221 with a distance from the boundary of the second gap 221 .
  • the position where the conductive protrusion is located is the boundary of the effective resonant region, that is, at least part of the boundary of the effective resonant region coincides with part of the boundary of the gap.
  • the positional relationship between the first conductive bump and the first gap, and the positional relationship between the second conductive bump and the second gap can be in various situations, for example, the first conductive bump is arranged at the boundary of the first gap or the A conductive bump is set at a distance from the boundary of the first gap, a part of the first conductive bump is set at the boundary of the first gap, and another part of the first conductive bump is set at a distance from the boundary of the first gap; and/or,
  • the second conductive bumps are arranged at the boundary of the second gap or, the second conductive bumps are set at a distance or from the boundary of the second gap, a part of the second conductive bumps are arranged at the boundary of the second gap, and the other part of the second conductive bumps A distance is provided between the protru
  • the first electrodes are all located on the carrier substrate and below the second electrodes, but in these embodiments, the second electrodes may all be located on the carrier substrate and below the first electrodes.
  • the manufacturing method for forming a thin film bulk acoustic wave resonator in the present invention includes: step S1, forming a first structure, and the first structure includes: a first electrode, a first sacrificial layer covering at least the first electrode, at least in the The side of the first sacrificial layer surrounds the dielectric layer of the first sacrificial layer; in step S2, a first conductive bump is formed, which penetrates the first sacrificial layer and is connected to the first electrode at one end; in step S3, a first electrode is formed to lead out one end is connected to the other end of the first conductive bump, and the other end extends out of the effective resonance region; step S4, forming a piezoelectric layer; step S5, forming a second structure, the second structure includes: a second structure.
  • step S6 forming a second conductive bump that penetrates the second sacrificial layer One end of the sacrificial layer is connected to the second electrode; step S7, a second electrode lead-out portion is formed, one end is connected to the other end of the second conductive bump, and the other end extends out of the effective resonance region; step S8, the The first sacrificial layer and the second sacrificial layer form the first gap and the second gap.
  • the sequence between the above steps may be performed sequentially, or may not be performed sequentially.
  • a temporary substrate is provided; steps S1-S3 are sequentially performed on the temporary substrate; after step S3 is performed, a carrier substrate is bonded on the side where the first electrode lead-out portion is located, and the temporary substrate is removed substrate; then, steps S5-S7 are sequentially performed on the carrier substrate.
  • the step S4 of forming the piezoelectric layer it can be formed before 1) performing step S1, or 2) after performing step S3 and before performing step S4, the piezoelectric layer is a film in which the effective resonance region and the inactive region are evenly distributed It can also be a patterned film layer that is located only in the effective resonance region. For details, refer to the detailed description in Example 4 below.
  • a carrier substrate is provided; step S3 is first performed on the carrier substrate to form the first electrode lead-out portion, and then steps S1 and S3 are performed; wherein, the respective structures between steps S1 and S3 are
  • the forming sequence may be: forming the first sacrificial layer and the first dielectric layer, then forming the first conductive bump, and then forming the first electrode. After that, steps S5-S7 are performed to form the second structure, the second conductive bump, and the second electrode lead-out portion.
  • the step S4 of forming the piezoelectric layer may: 1) The piezoelectric layer is formed during the process of forming the first electrode in step S1, for example, the first electrode layer, the piezoelectric layer and the second electrode layer are formed in sequence, and then the three The layer structure is patterned to form a first electrode, a piezoelectric layer, and a second electrode located in the effective resonance region. 2) After step S1 is performed, a flat layer can also be formed around the first electrode, wherein the surface of the flat layer is the same as that of the first electrode. The surface of the first electrode is flat, and then a piezoelectric layer is formed, and the piezoelectric layer is located in the effective resonance region and the ineffective resonance region. For details, reference may be made to the detailed description in Example 6 below.
  • a temporary substrate is provided; steps S1, S5, S6, and S7 are sequentially performed on the temporary substrate to form the first structure, the second structure, the second conductive bump, and the second electrode lead-out portion;
  • the carrier substrate is bonded on the side where the second electrode lead-out portion is located, and then the temporary substrate is removed; after bonding the carrier substrate, steps S2 and S3 are sequentially performed to form the first conductive bump, the the first electrode lead-out part.
  • the step S4 of forming the piezoelectric layer it can be formed after step S1 is performed in 1), and the formed piezoelectric layer is a film layer distributed in both the inactive area and the active area, or a film layer distributed only in the active area; Alternatively 2) after step S3 is performed and before step S4 is performed, the piezoelectric layer may be a film layer with both the effective resonance area and the ineffective area distributed, or may be a patterned film only located in the effective resonance area.
  • Example 5 Example 5 below.
  • FIGS. 4 to 13 are schematic structural diagrams corresponding to different steps in a method for manufacturing a thin film bulk acoustic resonator according to Embodiment 4 of the present invention, and the embodiment will be described in detail below with reference to FIGS. 4 to 13 .
  • a temporary substrate 200 is provided, on which a first structure, a first conductive bump, and a first electrode lead-out portion are formed.
  • a second electrode layer 203', a piezoelectric layer 202 and a first electrode layer 201' are formed on the temporary substrate 200.
  • the material of the temporary substrate 200 may be at least one of the following mentioned materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (Si), silicon carbon germanium (SiGe), arsenic Indium (Ins), Gallium Arsenide (Gs), Indium Phosphide (InP) or other III/V compound semiconductors.
  • an isolation layer may also be formed on the temporary substrate 200, and the isolation layer is located between the temporary substrate 200 and the second electrode layer 203'.
  • the isolation layer may be isolated by etching.
  • the temporary substrate 200 is separated from the second electrode layer 203 ′ formed later, which helps to peel off the temporary substrate quickly and improves the manufacturing efficiency of the process.
  • the temporary substrate can be removed by mechanical grinding or the like.
  • the materials of the isolation layers include but are not limited to at least one of silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3) and aluminum nitride (AlN).
  • the isolation layer can be formed by chemical vapor deposition, magnetron sputtering, or evaporation.
  • a second electrode layer 203' is deposited on the temporary substrate 200, then a piezoelectric layer 202 is deposited on the second electrode layer 203', and finally a first electrode layer 201' is deposited on the piezoelectric layer 202.
  • the piezoelectric layer 202 is formed on the flat second electrode layer 203', which can make the piezoelectric layer 202 have a better lattice orientation, improve the piezoelectric properties of the piezoelectric layer 202, and further improve the overall performance of the resonator.
  • the material of the piezoelectric layer 202 refers to the description of the foregoing structural embodiments.
  • the piezoelectric layer 202 may be deposited using any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition.
  • the materials of the first electrode layer 201 ′ and the second electrode layer 203 ′ can be formed by physical vapor deposition or chemical vapor deposition methods such as magnetron sputtering, evaporation, etc.
  • the first electrode layer 201' or the second electrode layer 203' can be formed by physical vapor deposition or chemical vapor deposition methods such as magnetron sputtering, evaporation, etc.
  • the first electrode layer 201 ′ is patterned to form the first electrode 201 .
  • the method of patterning the first electrode layer 201 ′ may use an etching process to etch the first electrode Layer 201 ′, the etching process can be wet etching or dry etching process, wherein preferably dry etching process is used, dry etching includes but not limited to reactive ion etching (RIE), ion beam Etching, plasma etching or laser cutting.
  • RIE reactive ion etching
  • the boundary of the first electrode 201 is located in the first gap formed subsequently, and the shape of the first electrode 201 is an irregular polygon.
  • a first sacrificial layer material is formed to cover the first electrode 201 and the piezoelectric layer 202 .
  • the first sacrificial material is patterned to form a first sacrificial layer 210 , and the first sacrificial layer 210 covers at least the first electrode 201 . Covering at least means that the boundary of the first sacrificial layer 210 coincides with the boundary of the first electrode or the boundary of the first sacrificial layer is located outside the boundary of the first electrode.
  • the first sacrificial layer also covers the piezoelectric layer 202 on the periphery of the first electrode 201 .
  • the first sacrificial layer 210 forms a first gap after being released in a subsequent process.
  • the area of the first sacrificial layer 210 determines the area of the first gap, and the height of the first sacrificial layer 210 determines the height of the first gap.
  • the material of the first sacrificial layer includes phosphosilicate glass, low temperature silicon dioxide, borophosphosilicate glass, germanium, carbon, polyimide or photoresist, and can be formed by chemical vapor deposition.
  • a dielectric layer 101A surrounding the first sacrificial layer at least on the side of the first sacrificial layer is formed, and a piezoelectric layer covering the first sacrificial layer 210 and the periphery of the first sacrificial layer 210 is formed 202.
  • the material of the dielectric layer 101A may be one or several combinations of silicon dioxide (SiO2), silicon nitride (Si3N4), aluminum oxide (Al2O3) and aluminum nitride, and may be formed by physical vapor deposition or chemical vapor deposition.
  • the surface of the dielectric layer 101A may also be level with the surface of the sacrificial layer.
  • first conductive bumps 301 are formed on the surface of the first electrode 201 .
  • a first through hole is formed to penetrate through the first sacrificial layer 210 and the dielectric layer 101A above the first sacrificial layer 210 , and a conductive material is formed in the first through hole to form the first conductive bump 301 .
  • the first through holes may be formed through an etching process or a punching process.
  • a conductive material may be formed in the first through hole by deposition or electroplating, and the conductive material includes low resistivity materials such as gold, silver, tungsten, platinum, aluminum, and copper.
  • the first conductive protrusion 301 is formed at the edge of the effective resonance region, and the position, structure and function of the first conductive protrusion 301 can be referred to the related description of the structure embodiment above.
  • release holes 212 are formed in the dielectric layer 101A above the first sacrificial layer, and the first sacrificial layer is removed through the release holes 212 .
  • the number of release holes may be multiple and distributed in different regions above the first sacrificial layer.
  • a corresponding removal method is adopted. For example, when the material of the first sacrificial layer is polyimide or photoresist, it is removed by ashing method. The ashing method is specifically at 250 degrees Celsius.
  • the oxygen in the release hole 212 chemically reacts with the material of the first sacrificial layer, and the generated gaseous substances are volatilized. Reaction removed. After removing the first sacrificial layer, a first gap 211 is formed between the surface of the first electrode 201 and the dielectric layer 101A.
  • forming a first electrode lead-out part includes: forming a first passivation layer; etching the first passivation layer to form a first groove; forming a first conductive groove in the first groove layer as the first electrode lead-out portion; or, forming a first conductive layer, patterning the first conductive layer to form the first electrode lead-out portion; forming a first passivation layer to cover the first electrode lead-out portion part; the first dielectric layer includes the first passivation layer.
  • the surfaces of the first passivation layer and the first electrode lead-out portion are flush, and then a dielectric layer can be formed on the flush surface to facilitate subsequent bearing linings Bottom bonding; when the first electrode lead-out portion is formed first and then the first passivation layer is formed, the surfaces of the first passivation layer and the first electrode lead-out portion are flush or cover the first electrode lead-out portion.
  • a dielectric layer is formed on the flush surface to facilitate subsequent bonding of the carrier substrate.
  • the first electrode lead-out portion 303 extends out of the area where the first gap 211 is located.
  • the first electrode lead-out portion 303 is strip-shaped and leads out from the side where the first gap 211 is located.
  • the first electrode lead-out portion 303 is planar. It should be understood that the function of the first electrode lead-out portion 303 is to connect external signals and play the role of electrical connection, and its shape and area can be flexibly selected according to the situation.
  • the method further includes forming a carrier substrate 100 on the upper surface of the first passivation layer 101B.
  • the carrier substrate 100 may be bonded on the first passivation layer 101B by means of bonding.
  • the material of the bonding layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride or ethyl silicate.
  • the first dielectric layer burying the first electrode lead-out portion 303 includes: a dielectric layer 101A and a first passivation layer 101B surrounding the first gap 211 .
  • the temporary substrate is removed.
  • the second structure, the second conductive bump, and the second electrode lead-out portion are sequentially formed on the carrier substrate.
  • the details are as follows: Referring to FIG. 11, the temporary substrate is removed.
  • the temporary substrate can be removed by etching the isolation layer. If there is no formation between the temporary substrate and the second electrode layer 203' isolation layer, the temporary substrate can be removed by mechanical grinding or the like.
  • the second electrode 203 is formed by patterning the second electrode layer.
  • the second electrode 203 and the first electrode 201 have the same shape and size, and are symmetrically arranged.
  • the shape of the second electrode and the shape of the first electrode may not be identical.
  • the edge of the second electrode 203 is located above the area enclosed by the first gap 211 .
  • the edge of the second electrode 203 is also located in the area enclosed by the second gap formed in the subsequent process.
  • a second sacrificial layer material is formed to cover the second electrode 203 and the piezoelectric layer 202 .
  • the second sacrificial material is patterned to form a second sacrificial layer 220 , and the first sacrificial layer 220 covers at least the second electrode 203 . Covering at least means that the boundary of the second sacrificial layer 210 coincides with the boundary of the second electrode 203 or the boundary of the second sacrificial layer 210 is located outside the boundary of the second electrode 203 .
  • the second sacrificial layer 220 also covers the piezoelectric layer 202 on the periphery of the second electrode 203 .
  • the second sacrificial layer 220 forms a second gap after being released in a subsequent process.
  • the material and formation method of the second sacrificial layer refer to the material and formation method of the first sacrificial layer.
  • a dielectric layer 102A (hereinafter referred to as the dielectric layer 102A) surrounding the second sacrificial layer at least on the side of the second sacrificial layer is formed, covering the second sacrificial layer 220 and the outer periphery of the second sacrificial layer.
  • Piezoelectric layer 202 For the material and formation method of the dielectric layer 102A, refer to the material and formation method of the dielectric layer 101A.
  • the illustrated embodiment shows that the dielectric layer 102A covers the top surface of the second sacrificial layer 220 , but the invention is not limited thereto, and the dielectric layer 102A may only be located around the second sacrificial layer 220 without the dielectric layer 102A on the top surface.
  • a second conductive bump 302 is formed, one end of which is connected to the second electrode, and the other end is exposed from the film layer above the second electrode.
  • the material and formation method of the second conductive bump 302 reference may be made to the material and formation method of the first conductive bump, and details are not described herein again.
  • release holes are formed in the dielectric layer 102A above the second sacrificial layer, and the second sacrificial layer is removed through the release holes to form a second layer between the upper surface of the second electrode 203 and the first layer of the second dielectric layer 102A Gap 221.
  • the second electrode lead-out portion 304 includes: forming a second passivation layer 102B; etching the second passivation layer to form a second groove; forming a second conductive layer in the second groove as the second electrode lead-out portion; or, forming a second conductive layer, patterning the second conductive layer to form the second electrode lead-out portion; forming a second passivation layer to cover the second electrode lead-out portion; the second medium
  • the layer 102 includes the second passivation layer 102B and the dielectric layer 102A surrounding the second gap 221 .
  • the surfaces of the second passivation layer and the second electrode lead-out portion are flush, and then a dielectric layer can be formed on the flush surface for protection
  • the material of the second electrode lead-out portion 304 refers to the material of the first electrode lead-out portion 303 .
  • the second electrode lead-out portion 304 extends out of the area where the second gap 221 is located.
  • the second electrode lead-out portion 304 is strip-shaped, and leads out from the side where the second gap 211 is located to the outside, outside the effective resonance area,
  • the projections of the first electrode lead-out portion 303 and the second electrode lead-out portion 304 in the direction of the piezoelectric layer 202 are offset from each other.
  • a release hole may be formed to remove the second sacrificial layer.
  • a second electrode layer, a piezoelectric layer, and a first electrode layer are sequentially formed on the temporary substrate; after that, the first electrode layer is patterned to form the first electrode; after the first structure is formed, After bonding the carrier substrate to remove the temporary substrate, the second electrode layer is patterned to form a second electrode; and then a second structure, a second electrode lead-out portion, and a second conductive bump are formed.
  • the first electrode or the second electrode is formed by etching, the piezoelectric layer is not etched all the time, the integrity of the piezoelectric layer is preserved, and the piezoelectric layer is distributed in both the active area and the inactive area.
  • the first gap and The second gap is separated from each other by the piezoelectric layer. Therefore, the first sacrificial layer and the second sacrificial layer are not connected to each other and need to be removed respectively.
  • the piezoelectric layer after forming the first electrode or after forming the second electrode, can be patterned to remove the piezoelectric layer in the inactive region or form an air edge around the piezoelectric layer in the effective resonance region gap.
  • the advantages of this kind of situation please refer to the description of the corresponding part in the structural embodiment.
  • the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer.
  • the second sacrificial layers are communicated with each other, and the first sacrificial layer and the second sacrificial layer can be removed simultaneously.
  • the second electrode layer, piezoelectric layer and first electrode layer in sequence on the temporary substrate, pattern the first electrode layer, piezoelectric layer and second electrode layer, and remove the part of the first electrode layer located in the inactive area , a piezoelectric layer part, a second electrode layer part to form the first electrode, the second electrode, and the piezoelectric layer; then, the first sacrificial layer and the first dielectric layer are formed, and the first sacrificial layer covers The first electrode, the second electrode, the top surface and the side surface of the piezoelectric layer.
  • a first conductive bump and a first electrode lead-out portion are formed; then, the carrier substrate is bonded, the temporary substrate is removed, and a second sacrificial layer, a second conductive bump, and a second electrode are formed
  • the first sacrificial layer and the second sacrificial layer are communicated with each other, and the first sacrificial layer and the second sacrificial layer can be removed simultaneously.
  • the piezoelectric layer and the first electrode layer are sequentially formed on the temporary substrate; the first electrode layer is patterned to form the first electrode. Then, referring to the method of Embodiment 4, the first sacrificial layer and the first dielectric layer are formed, and the first sacrificial layer covers the top surface and the side surface of the first electrode; Electrode lead-out part; continue referring to the method of the embodiment, remove the temporary substrate, bond the carrier substrate, and turn it over to form a second electrode layer, and pattern the second electrode layer to form the second electrode. Then, continuing to refer to the method of Embodiment 4, a second conductive bump, a second electrode lead-out portion, a second sacrificial layer, a second dielectric layer, and the like are formed.
  • the piezoelectric layers can be kept distributed in both the inactive region and the effective resonance region. At this time, since the first sacrificial layer and the second sacrificial layer are separated from each other, the first sacrificial layer and the second sacrificial layer need to removed separately.
  • the piezoelectric layer may be patterned to remove the piezoelectric layer in the inactive region or the piezoelectric layer in the effective resonance region. An air gap is formed around the piezoelectric layer.
  • the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer.
  • the first sacrificial layer and the second sacrificial layer are The layers are connected with each other, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.
  • the second electrode layer, the piezoelectric layer, and the first electrode layer are not sequentially formed on the temporary substrate.
  • a first electrode and a flat layer are formed on the temporary substrate, and the surfaces of the first electrode and the flat layer are flush; after that, referring to the method of Embodiment 4, a first sacrificial layer and a first dielectric are formed layer, a first conductive bump, and a first electrode lead-out portion.
  • the carrier substrate is bonded, the temporary substrate is removed, and a piezoelectric layer is formed on the flush surface of the first electrode and the flat layer on the carrier substrate.
  • the piezoelectric layer may be located in the effective resonance region and the inactive region.
  • the first sacrificial layer and the second sacrificial layer are separated from each other and need to be removed respectively.
  • the piezoelectric layer may be patterned before or after the second electrode layer is patterned to remove the piezoelectric layer in the inactive region or form air around the piezoelectric layer in the effective resonance region side gap.
  • the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer.
  • the first sacrificial layer and the second sacrificial layer are The layers are connected with each other, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.
  • the first electrode is located below the second electrode.
  • the first electrode is located above the second electrode.
  • Embodiment 5 of the present invention provides a method for manufacturing a thin-film bulk acoustic resonator.
  • FIGS. 15 to 21 are schematic structural diagrams corresponding to different steps in a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 5 of the present invention. The present embodiment will be described in detail with reference to FIGS. 15 to 21 .
  • a temporary substrate 200 is provided; the material of the temporary substrate 200 may refer to the related content of Embodiment 4.
  • the first structure is formed on the temporary substrate 200 . It includes: firstly forming a first sacrificial layer 210 and a dielectric layer 101A surrounding the first sacrificial layer, and then forming a first electrode 201, the first sacrificial layer only covers the top surface of the first electrode (the surface close to the temporary substrate) Or cover the top surface and side surface of the first electrode.
  • the dielectric layer 101A covers the side surfaces of the first sacrificial layer and the side surfaces of the first electrode or covers the side surfaces, the top surface and the side surfaces of the first electrode of the first sacrificial layer.
  • the specific method for forming the first electrode includes: referring to FIG. 16 , etching the first sacrificial layer to form a groove, and filling the groove with a conductive material as the first electrode. If the conductive material is formed outside the groove, the groove needs to be removed. The conductive material outside the groove can be removed by chemical mechanical grinding or etching.
  • a variant of forming the first electrode may also be: forming a first electrode layer on the surfaces of the first sacrificial layer 210 and the dielectric layer 101A, and then patterning the first electrode layer to form the first electrode 201 . At this time, the first electrode is located on the first sacrificial layer instead of being embedded in the first sacrificial layer.
  • the method for forming the first sacrificial layer 210 and the dielectric layer 101A may refer to Embodiment 4.
  • a piezoelectric layer 202 is formed on the temporary substrate.
  • a second structure is formed on the temporary substrate.
  • the specific method includes: forming a second electrode layer, patterning the second electrode layer to form a second electrode 203 ; and then forming a second sacrificial layer 220 and a dielectric layer 102A surrounding the second sacrificial layer 220 .
  • the relevant content in Embodiment 4 can be cited here.
  • a second conductive bump 302 and a second electrode lead-out portion 304 are formed on the temporary substrate 200 ; the first sacrificial layer is removed.
  • the second passivation layer 102B is also formed.
  • the relevant content in Embodiment 4 can be cited here.
  • the second dielectric layer 102 includes a dielectric layer 102A and a second passivation layer 102B.
  • the carrier substrate 100 is bonded on the side where the second electrode lead-out portion 304 is located, and then the temporary substrate is removed; after bonding the carrier substrate, the first conductive bumps 301 and 301 are formed in sequence.
  • the first electrode lead-out portion 303 During the process of forming the first electrode lead-out portion 303, the first passivation layer 101B is also formed.
  • the relevant content in Embodiment 4 can be cited here.
  • the first dielectric layer 101 includes a dielectric layer 101A and a second passivation layer 101B.
  • the method of removing the first sacrificial layer and the second sacrificial layer in the fourth embodiment can be cited in the fifth embodiment.
  • Example 5 after the first electrode is formed, the piezoelectric layer is formed, and then the second electrode is formed, wherein the formation of the first electrode layer, the piezoelectric layer, and the second electrode layer is not in order.
  • the piezoelectric layer is not etched in sequence, the integrity of the piezoelectric layer is preserved, and the piezoelectric layer is distributed in both the active area and the inactive area, and the first gap and the second gap pass through the piezoelectric layer They are separated from each other, therefore, the first sacrificial layer and the second sacrificial layer are not connected to each other and need to be removed separately.
  • the piezoelectric layer may be patterned to remove the piezoelectric layer in the inactive region or form an air gap around the piezoelectric layer in the effective resonance region .
  • the advantages of this kind of situation please refer to the description of the corresponding part in the structural embodiment.
  • the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer.
  • the second sacrificial layers are communicated with each other, and the first sacrificial layer and the second sacrificial layer can be removed simultaneously.
  • the second electrode layer, the piezoelectric layer and the first electrode layer are sequentially formed on the temporary substrate, and then the first electrode layer, the piezoelectric layer and the piezoelectric layer are patterned.
  • layer, the second electrode layer, the first electrode layer part, the piezoelectric layer part, and the second electrode layer part located in the invalid area are removed to form the first electrode, the second electrode, and the piezoelectric layer;
  • a second sacrificial layer and a second dielectric layer, and the second sacrificial layer covers the top and side surfaces of the first electrode, the second electrode, and the piezoelectric layer.
  • the second conductive bumps, the second electrode lead-out portions are formed; then, the carrier substrate is bonded, the temporary substrate, the first conductive bumps, the first electrode lead-out portions, and the like are removed.
  • the first sacrificial layer and the second sacrificial layer are communicated with each other, and the first sacrificial layer and the second sacrificial layer can be removed simultaneously.
  • Example 5 After the first dielectric layer and the first sacrificial layer are formed on the temporary substrate, a first electrode and a flat layer are formed on the temporary substrate, and the surfaces of the first electrode and the flat layer are flush; After that, referring to the method of Example 5, a piezoelectric layer was formed. For the formation steps and methods of the subsequent structures, refer to Example 5.
  • the piezoelectric layer may be located in the effective resonance region and the inactive region.
  • the first sacrificial layer and the second sacrificial layer are separated from each other and need to be removed respectively.
  • the piezoelectric layer may also be patterned before or after the second electrode layer is patterned to remove the piezoelectric layer in the inactive region or form air around the piezoelectric layer in the effective resonance region side gap.
  • the first sacrificial layer still exists, and the second sacrificial layer is also filled around the patterned piezoelectric layer.
  • the first sacrificial layer and the second sacrificial layer are The layers are connected with each other, and the first sacrificial layer and the second sacrificial layer can be removed at the same time.
  • Embodiment 6 of the present invention provides a method for manufacturing a thin-film bulk acoustic resonator.
  • FIGS. 22 to 30 are schematic structural diagrams corresponding to different steps in a method for manufacturing a thin-film bulk acoustic resonator according to Embodiment 6 of the present invention. The present embodiment will be described in detail with reference to FIGS. 22 to 30 .
  • a carrier substrate 100 is provided, and a first electrode lead-out portion 303 is formed on the carrier substrate 100.
  • the material of the first electrode lead-out portion 303 refers to Embodiment 1, and the first conductive layer can be formed by a physical vapor deposition method, Then, the first conductive layer is patterned to form the first electrode lead-out portion 303 .
  • the relevant content in Embodiment 4 can be cited here.
  • a first dielectric layer 101 and a first sacrificial layer 210 are formed.
  • the first dielectric layer 101 is formed on and above the first electrode lead-out portion 303 , the first dielectric layer 101 is etched to form a first gap 211 , and one end of the first electrode lead-out portion 303 is located in the first gap 211 , the other end is located outside the first gap 211 , and a part of the first dielectric layer may remain on the upper surface of the first electrode lead-out portion 303 , or the first electrode lead-out portion 303 may be exposed at the bottom of the first gap 211 .
  • the first sacrificial layer 210 is filled in the first gap.
  • the material and formation method of the first sacrificial layer refer to Embodiment 4.
  • the upper surfaces of the first sacrificial layer 210 and the first dielectric layer 101 are flush.
  • the first sacrificial layer may be formed first, and then the first dielectric layer may be formed.
  • the relevant content in Embodiment 4 can be cited here.
  • a first conductive bump 210 is formed in the first sacrificial layer, and the lower end of the first conductive bump 210 is connected to the first electrode lead-out portion 303 .
  • Contents related to the structure, shape, and position of the first conductive bumps 210 in Embodiment 4 can be cited here.
  • a first electrode layer 201 ′, a piezoelectric layer 202 , and a second electrode layer 203 ′ are sequentially formed on the first sacrificial layer 210 and the first dielectric layer 101 , and the materials and forming methods of the three refer to the embodiments. 4.
  • the second electrode layer 203', the piezoelectric layer 202, and the first electrode layer 201' are etched to form the second electrode 203, the piezoelectric layer 202, and the first electrode 201.
  • the edges of the three All are located above the area surrounded by the first sacrificial layer 210, and the boundaries of the three are coincident.
  • the boundaries of the three constitute the boundary of the effective resonance area, and the first conductive protrusion 301 is located at the boundary of the effective resonance area.
  • the second electrode layer 203', the piezoelectric layer 202, and the first electrode layer 201' are etched synchronously to save process time.
  • a second sacrificial layer 220 is formed, the second sacrificial layer 220 covers the surface of the second electrode 203 and the second electrode 203 , the piezoelectric layer 202 , the outer periphery 220 of the first electrode 201 , and the outer periphery of the second sacrificial layer 220
  • a second dielectric layer 102 is formed.
  • the materials and forming methods of the second sacrificial layer 220 and the second dielectric layer 102 refer to Embodiment 4.
  • a second conductive bump 302 is formed in the second sacrificial layer 220 , a second electrode lead-out portion 304 is formed on the upper surface of the second sacrificial layer 220 , and one end of the second electrode lead-out portion 304 is located in the second sacrificial layer 220 Within the boundary of , the other end is located on the second dielectric layer 102 outside the second sacrificial layer 220 .
  • a dielectric layer is formed on the second sacrificial layer 220 , the second electrode lead-out portion 304 and the second dielectric layer 102 around the second sacrificial layer 220 to cover the second electrode lead-out portion 304 .
  • the first and second sacrificial layers are removed to form first and second gaps 211 and 221 .
  • the first sacrificial layer and the second sacrificial layer are in contact with each other, and both are made of the same material and can be removed at one time.
  • Release holes may be formed in the second dielectric layer 102 over the second sacrificial layer, and removed through the release holes.
  • Example 6 after forming the first electrode lead-out portion, the first structure, and the first conductive bump, the first electrode layer, the piezoelectric layer and the second electrode layer are sequentially deposited, and then the three-layer structure is patterned.
  • the corresponding first sacrificial layer and the second sacrificial layer communicate with each other, so they can be removed simultaneously.
  • the piezoelectric layer is patterned to remove the piezoelectric layer in the inactive region or form an air gap around the piezoelectric layer in the effective resonance region.
  • the second sacrificial layer will fill in the disconnected area around the piezoelectric layer in the effective resonance region, so the first sacrificial layer and the second sacrificial layer are communicated and can be removed at the same time.

Landscapes

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

Abstract

L'invention concerne un résonateur acoustique de volume à couches et son procédé de fabrication. Le résonateur acoustique de volume à couches comprend : une première électrode, une couche piézoélectrique et une deuxième électrode qui sont empilées ; une zone de résonance efficace qui comprend une zone dans laquelle la première électrode, la couche piézoélectrique et la deuxième électrode se chevauchent dans une direction perpendiculaire à la surface de la couche piézoélectrique, la zone à l'extérieur de la zone de résonance efficace étant une zone inefficace ; une première couche diélectrique, un premier espace étant disposé entre la surface supérieure de la première couche diélectrique et une surface inférieure de la première électrode ; une deuxième couche diélectrique, un deuxième espace étant disposé entre la surface inférieure de la deuxième couche diélectrique et une surface supérieure de la deuxième électrode ; une première saillie conductrice, dont une extrémité est disposée sur la surface inférieure de la première électrode, et dont l'autre extrémité est connectée à une première partie de sortie d'électrode ; et une deuxième saillie conductrice, dont une extrémité est disposée sur la surface supérieure de la deuxième électrode, et dont l'autre extrémité est connectée à une deuxième partie de sortie d'électrode. Au moyen de la présente invention, le facteur qualité d'un résonateur est amélioré.
PCT/CN2021/105531 2020-07-14 2021-07-09 Résonateur acoustique de volume à couches et son procédé de fabrication WO2022012438A1 (fr)

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CN114900147B (zh) * 2022-07-08 2022-11-01 深圳新声半导体有限公司 体声波谐振器及其制造方法

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