WO2020199511A1 - 体声波谐振器及其制造方法和滤波器、射频通信系统 - Google Patents

体声波谐振器及其制造方法和滤波器、射频通信系统 Download PDF

Info

Publication number
WO2020199511A1
WO2020199511A1 PCT/CN2019/105096 CN2019105096W WO2020199511A1 WO 2020199511 A1 WO2020199511 A1 WO 2020199511A1 CN 2019105096 W CN2019105096 W CN 2019105096W WO 2020199511 A1 WO2020199511 A1 WO 2020199511A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
bottom electrode
sacrificial
electrode
cavity
Prior art date
Application number
PCT/CN2019/105096
Other languages
English (en)
French (fr)
Inventor
罗海龙
Original Assignee
中芯集成电路（宁波）有限公司上海分公司
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 中芯集成电路（宁波）有限公司上海分公司 filed Critical 中芯集成电路（宁波）有限公司上海分公司
Priority to JP2021525816A priority Critical patent/JP7194476B2/ja
Publication of WO2020199511A1 publication Critical patent/WO2020199511A1/zh
Priority to US17/449,836 priority patent/US20220029603A1/en

Links

Images

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
    • 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
    • H03H9/02086—Means for compensation or elimination of undesirable effects
    • H03H9/02133—Means for compensation or elimination of undesirable effects of stress

Definitions

  • the invention relates to the technical field of radio frequency communication, in particular to a bulk acoustic wave resonator, a manufacturing method thereof, a filter, and a radio frequency communication system.
  • Radio frequency (RF) communications such as those used in mobile phones, require radio frequency filters. Each radio frequency filter can pass the required frequency and limit all other frequencies.
  • RF Radio frequency
  • the amount of mobile data transmission has also risen rapidly. Therefore, under the premise that frequency resources are limited and as few mobile communication devices as possible should be used, increasing the transmission power of wireless power transmitting devices such as wireless base stations, micro base stations, or repeaters has become a problem that must be considered, and it also means that The power requirements of filters in the front-end circuits of mobile communication equipment are also increasing.
  • high-power filters in equipment such as wireless base stations are mainly cavity filters, whose power can reach hundreds of watts, but the size of such filters is too large.
  • Some equipment uses dielectric filters, the average power of which can reach more than 5 watts, and the size of this filter is also very large. Due to the large size, these two filters cannot be integrated into the RF front-end chip.
  • a filter composed of a bulk acoustic wave (BAW) resonator can well overcome the shortcomings of the above two types of filters.
  • the bulk acoustic wave resonator has the incomparable volume advantages of ceramic dielectric filters, the incomparable operating frequency and power capacity advantages of surface acoustic wave (SAW) resonators, and has become the development trend of today's wireless communication systems.
  • the main part of the bulk acoustic wave resonator is a "sandwich" structure composed of bottom electrode-piezoelectric film-top electrode.
  • the inverse piezoelectric effect of the piezoelectric film is used to convert electrical energy into mechanical energy, and the bulk acoustic wave resonator is formed in the form of sound waves.
  • a standing wave is formed in the filter. Since the speed of acoustic waves is 5 orders of magnitude smaller than that of electromagnetic waves, the size of the filter composed of bulk acoustic wave resonators is smaller than that of traditional dielectric filters.
  • One of the cavity-type bulk acoustic wave resonators its working principle is to use sound waves to reflect on the interface between the bottom electrode or the support layer and the air to confine the sound waves to the piezoelectric layer to achieve resonance. It has high Q value and low insertion The advantages such as loss and integration are widely adopted.
  • the quality factor (Q) of the currently manufactured cavity-type bulk acoustic resonator cannot be further improved, and therefore cannot meet the requirements of high-performance radio frequency systems.
  • the purpose of the present invention is to provide a bulk acoustic wave resonator, a manufacturing method thereof, a filter, and a radio frequency communication system, which can improve the quality factor and thereby improve the performance of the device.
  • the present invention provides a bulk acoustic wave resonator including:
  • the bottom electrode layer is disposed on the substrate, and a cavity is formed between the bottom electrode layer and the substrate, the bottom electrode layer has a bottom electrode protrusion, and the bottom electrode protrusion is located
  • the area of the cavity is convex in a direction away from the bottom surface of the cavity;
  • the top electrode layer is formed on the piezoelectric resonance layer, and the part of the top electrode layer above the cavity is flat and extended.
  • the present invention also provides a filter including at least one bulk acoustic wave resonator according to the present invention.
  • the present invention also provides a radio frequency communication system including at least one filter according to the present invention.
  • the present invention also provides a method for manufacturing a bulk acoustic wave resonator, including:
  • the second sacrificial layer and the first sacrificial layer having the sacrificial protrusions are removed, the positions of the second sacrificial layer and the first sacrificial layer form a cavity, and the bottom electrode protrusions are located In the cavity area on the periphery of the piezoelectric resonance layer, and the part of the top electrode layer above the cavity is flat and extended.
  • the piezoelectric phenomenon generated in the piezoelectric resonance layer When electric energy is applied to the bottom electrode and the top electrode, the piezoelectric phenomenon generated in the piezoelectric resonance layer generates desired longitudinal waves propagating in the thickness direction and undesired transverse waves propagating along the plane of the piezoelectric resonance layer.
  • the transverse wave will be blocked at the protrusion of the bottom electrode on the cavity on the periphery of the piezoelectric resonance layer, and will be reflected back to the area corresponding to the piezoelectric resonance layer, thereby reducing and reducing the propagation of the transverse wave to the periphery of the cavity.
  • the loss caused by the time in the film layer thereby improving the acoustic wave loss, so that the quality factor of the resonator is improved, and finally the performance of the device can be improved.
  • the periphery of the piezoelectric resonant layer is separated from the periphery of the cavity, that is, the piezoelectric resonant layer does not continuously extend above the substrate on the periphery of the cavity, which can completely limit the effective working area of the bulk acoustic wave resonator to the cavity area
  • the bottom electrode overlap portion and the top electrode overlap portion will only extend above the part of the substrate surrounding the cavity (that is, neither the bottom electrode layer nor the top electrode layer will fully cover the cavity), thereby enabling Reduce the influence of the film layer around the cavity on the longitudinal vibration generated by the piezoelectric resonance layer and improve the performance.
  • the overlapped part is still a gap structure, which can greatly reduce the parasitic parameters and avoid the top electrode layer and the bottom electrode layer in the cavity area Problems such as electrical contact in the device can improve device reliability.
  • the overlapping parts of the bottom electrode overlap portion and the top electrode overlap portion and the cavity are all suspended, and the bottom electrode overlap portion and the top electrode overlap portion are staggered in the cavity area, which can greatly reduce Parasitic parameters, and avoid problems such as leakage and short circuit caused by the contact between the bottom electrode overlap portion and the top electrode overlap portion, and the reliability of the device can be improved.
  • the bottom electrode overlap part completely covers the cavity above the cavity part where it is located, so that a large area of the bottom electrode overlap part can be used to provide strong mechanical support for the film layer above it. Therefore, the problem of device failure due to cavity collapse is avoided.
  • the protruding part of the bottom electrode surrounds the resonant part of the bottom electrode, which can block transverse waves in all directions from the periphery of the piezoelectric resonance layer, thereby obtaining a better quality factor.
  • the bottom electrode protruding part, the bottom electrode resonance part and the bottom electrode overlap part are formed by the same film layer, and the film thickness is uniform, and the top electrode resonance part and the top electrode overlap part are formed by the same film layer, and the film thickness is uniform.
  • the process can be simplified and the cost can be reduced, and because the film thickness of the bottom electrode protrusion is basically the same as the other parts of the bottom electrode layer, the bottom electrode protrusion will not be broken, and the reliability of the device can be improved.
  • the part of the top electrode layer located above the cavity area is flat and extended. On the one hand, it can help improve the thickness uniformity of the film in the effective area, and on the other hand, it provides a flat process surface for subsequent processes to avoid subsequent films. In the layer etching process, the problem of etching residue occurs due to the uneven top surface of the top electrode layer in the cavity region, thereby reducing parasitic parameters.
  • FIG. 1A is a schematic top view of a bulk acoustic wave resonator according to an embodiment of the invention.
  • Figures 1B and 1C are schematic cross-sectional structural views taken along the lines XX' and YY' in Figure 1.
  • FIGS. 2A to 2C are schematic top views of the structure of the bulk acoustic wave resonator according to other embodiments of the present invention.
  • 2D is a schematic cross-sectional structure diagram of a bulk acoustic wave resonator according to another embodiment of the invention.
  • Fig. 3 is a flowchart of a method of manufacturing a bulk acoustic wave resonator according to an embodiment of the present invention.
  • 4A to 4G are schematic cross-sectional views taken along XX' in FIG. 1A in a method of manufacturing a bulk acoustic wave resonator according to an embodiment of the present invention.
  • FIG. 5 is a schematic cross-sectional view along XX' in FIG. 1A in a method for manufacturing a bulk acoustic wave resonator according to another embodiment of the present invention.
  • FIG. 1A is a schematic diagram of a top view of a bulk acoustic wave resonator according to an embodiment of the present invention.
  • FIG. 1B is a schematic diagram of a cross-sectional structure along XX′ in FIG. 1
  • FIG. 1C is a diagram along YY in FIG.
  • a schematic cross-sectional structure diagram of the line, the bulk acoustic wave resonator of this embodiment includes: a substrate, a bottom electrode layer 104, a piezoelectric resonance layer 1051, and a top electrode layer 107.
  • the substrate includes a base 100 and an etching protection layer 101 covering the base 100.
  • the substrate 100 may be any suitable substrate known to those skilled in the art, for example, it may be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), carbon Silicon (SiC), carbon germanium silicon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III/V compound semiconductors, including multilayer structures composed of these semiconductors, etc.
  • silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon germanium-on-insulator (S-SiGeOI), silicon germanium-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), or Double-Side Polished Wafers (DSP) can also be ceramic substrates such as alumina, quartz or glass substrates.
  • the material of the etching protection layer 101 can be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, and the like.
  • the etching protection layer On the one hand, it can be used to increase the structural stability of the final bulk acoustic wave resonator, increase the isolation between the bulk acoustic wave resonator and the substrate 100, and reduce the resistivity requirements of the substrate 100. On the other hand, it can also be used in the manufacture of During the process of the acoustic wave resonator, other areas of the substrate are protected from etching, thereby improving the performance and reliability of the device.
  • a cavity 102 is formed between the bottom electrode layer 104 and the substrate. 1A to 1C, in this embodiment, the cavity 102 can be formed by sequentially etching the etching protection layer 101 and a part of the thickness of the substrate 100 through an etching process, forming a whole bottom recessed The groove structure in the substrate.
  • the technology of the present invention is not limited to this. Please refer to FIG. 2D.
  • the cavity 102 may also be formed by passing a sacrificial layer protruding on the surface of the etching protection layer 101. The removal process is formed above the top surface of the etching protection layer 101 to form a cavity structure protruding on the surface of the etching protection layer 101 as a whole.
  • the shape of the bottom surface of the cavity 102 is rectangular, but in other embodiments of the present invention, the shape of the bottom surface of the cavity 102 may also be a circle, an ellipse, or a polygon other than a rectangle, such as five Hexagons, hexagons, etc.
  • the piezoelectric resonant layer 1051 can also be called a piezoelectric resonator, and is located in the upper region of the cavity 102 (in other words, located in the region of the cavity 102), corresponding to the effective working area of the bulk acoustic wave resonator, And the piezoelectric resonance layer 1051 is provided between the bottom electrode layer 104 and the top electrode layer 107.
  • the bottom electrode layer 104 includes a bottom electrode lap portion 1040, a bottom electrode protrusion 1041, and a bottom electrode resonant portion 1042 that are sequentially connected
  • the top electrode layer 107 includes a top electrode lap portion 1070 and a top electrode resonant portion 1071 that are sequentially connected.
  • the electrode resonance portion 1042 and the top electrode resonance portion 1071 overlap the piezoelectric resonance layer 1051, and the cavity 102 overlaps the bottom electrode resonance portion 1042, the piezoelectric resonance layer 1051, and the area corresponding to the top electrode resonance portion 1071.
  • the effective working area 102A of the bulk acoustic wave resonator is constituted.
  • the cavity 102 except the effective working area 102A is the invalid area 102B.
  • the piezoelectric resonance layer 1051 is located in the effective working area 102A and separated from the film layer around the cavity 102 ,
  • the effective working area of the bulk acoustic wave resonator can be completely restricted in the cavity 102 area, and the influence of the film layer around the cavity on the longitudinal vibration generated by the piezoelectric resonator layer can be reduced, and the parasitic generated in the ineffective area 102B can be reduced. Parameters to improve device performance.
  • the bottom electrode resonator portion 1042, the piezoelectric resonant layer 1051, and the top electrode resonator portion 1071 are all flat structures with flat upper and lower surfaces, and the bottom electrode protruding portion 1041 is located above the cavity 102B on the periphery of the effective working area 102A.
  • the bottom electrode resonant portion 1042 is connected to and protrudes away from the bottom surface of the cavity.
  • the bottom electrode protruding portion 1041 is lower than the top surface of the bottom electrode resonant portion 1042 as a whole.
  • the bottom electrode protrusion 1041 can be a solid structure or a hollow structure, preferably a hollow structure, so that the film thickness of the bottom electrode layer 104 can be made uniform, and the gravity of the solid bottom electrode protrusion 1041 can avoid the bottom electrode resonance.
  • the portion 1042 is separated from the piezoelectric resonance layer 1051, thereby further improving the resonance factor.
  • the bottom electrode resonant portion 1042 and the top electrode resonant portion 1071 are all polygons (both the top surface and the bottom surface are polygonal), and the shape of the bottom electrode resonant portion 1042 and the top electrode resonant portion 1071 may be similar (As shown in Figures 2A-2B and 2D) or exactly the same (as shown in Figures 1A and 2C).
  • the piezoelectric resonance layer 1051 has a polygonal structure similar to the shape of the bottom electrode resonance portion 1042 and the top electrode resonance portion 1071.
  • the part of the top electrode layer 107 above the cavity 102 extends flat, that is, the top surface of the part of the top electrode overlap portion 1070 above the cavity is flush with the top surface of the top electrode resonance portion 1071, and the top electrode The bottom surface of the overlapping portion 1070 above the cavity is flush with the bottom surface of the top electrode resonance portion 1071.
  • the bottom electrode layer 104, the piezoelectric resonance layer 1051, and the top electrode layer 107 form a "watch"-shaped film structure, and the bottom electrode overlap portion 1040 and the bottom electrode resonate One corner of the part 1042 is aligned, one corner of the top electrode overlapping part 10740 and the top electrode resonant part 1071 are aligned, the bottom electrode overlapping part 1040 and the top electrode overlapping part 1070 are equivalent to the two straps of a "watch".
  • the bottom electrode protruding portion 1041 is arranged along the side of the bottom electrode resonating portion 1042 and is only provided in the area where the bottom electrode overlapping portion 1040 and the bottom electrode resonating portion 1042 are aligned.
  • the bottom electrode protruding portion 1041 is equivalent to the connection structure between the dial of a "watch" and a strap.
  • the bottom electrode resonant part 1042 in the effective area 102A is the piezoelectric resonant layer 1051 and the top electrode resonant part 1071 stacked structure is equivalent to the dial of a watch. Except for the part of the strap that is connected to the film layer on the substrate surrounding the cavity, the remaining parts are separated from the film layer on the substrate surrounding the cavity through the cavity. That is, in this embodiment, the bottom electrode protrusion 1041 extends around the peripheral direction of the piezoelectric resonance layer 1051, and the bottom electrode protrusion 1041 surrounds the piezoelectric resonance layer 1051 in the peripheral direction of the piezoelectric resonance layer 1051.
  • the top electrode lap portion 1070 and the bottom electrode protrusion 1041 are located on both sides of the piezoelectric resonant layer 1051 and are completely opposite to each other, and take the plane where the piezoelectric resonance layer 1051 is located as a reference.
  • the top electrode lap portion 1070 and the bottom lap portion 1040 are located on both sides of the piezoelectric resonance layer 1051 and are completely opposite, so that while achieving a certain transverse wave blocking effect, it can be beneficial to the top electrode lap portion 1070 and the bottom
  • the area of the invalid region 102B not covered by the electrode overlap portion 1040 is reduced, thereby contributing to the reduction of the device size, and at the same time, reducing the area of the top electrode overlap portion 1070 and the bottom electrode overlap portion 1040 to further Reduce parasitic parameters and improve the electrical performance of the device.
  • the bottom electrode lap portion 1040 is electrically connected to the side of the bottom electrode protrusion 1041 facing away from the bottom electrode resonance portion 1042, and is suspended from the bottom electrode protrusion 1041 on the bottom electrode protrusion.
  • the cavity (ie 102B) outside the rising portion 1041 extends above the part of the etching protection layer 101 on the periphery of the cavity 102;
  • the top electrode lap portion 1070 is electrically connected to one of the top electrode resonance portion 1071 Side, and extend from the top electrode resonance portion 1071 over the cavity (ie 102B) outside the top electrode resonance portion 1071 and then extend to the part of the etching protection layer 101 on the periphery of the cavity 102;
  • the bottom electrode lap portion 1040 and the top electrode lap portion 1070 extend above the substrate outside the two opposite sides of the cavity 102, and the bottom electrode lap portion 1040 and the top electrode overlap
  • the contacts 1070 are staggered in the cavity 102 area (that is, the two do not overlap), thus, the parasitic parameters can be
  • the bottom electrode lap portion 1040 can be used to connect a corresponding signal line to transmit a corresponding signal to the bottom electrode resonance portion 1042 through the bottom electrode protrusion 1041, and the top electrode lap portion 1070 can be used to connect a corresponding signal line.
  • the top electrode resonance part 1071 applies a time-varying voltage to excite the longitudinal extension mode or "piston" mode.
  • the piezoelectric resonance layer 1051 converts energy in the form of electrical energy into longitudinal waves. In this process, parasitic transverse waves are generated.
  • the bottom electrode protrusion 1041 These transverse waves can be blocked from propagating into the film layer surrounding the cavity and confined within the cavity 102, thereby avoiding the energy loss caused by the transverse waves and improving the quality factor.
  • the line width of the bottom electrode protrusion 1041 is the minimum line width allowed by the corresponding process, and the horizontal distance between the bottom electrode protrusion 1041 and the piezoelectric resonance layer 1051 is the minimum distance allowed by the corresponding process, Therefore, while the bottom electrode protrusion 1041 can achieve a certain transverse wave blocking effect, it can help reduce the device area.
  • the sidewall of the bottom electrode protrusion 1041 is an inclined sidewall relative to the bottom surface of the piezoelectric resonance layer, as shown in FIG. 1B, the bottom electrode protrusion 1041 is a cross-section along the line XX' in FIG.
  • the bottom electrode resonant portion 1042, the bottom electrode protruding portion 1041, and the bottom electrode overlap portion 1040 are formed by the same film layer manufacturing process (ie, the same film layer manufacturing process), and the top electrode resonates
  • the portion 1071 and the top electrode overlap portion 1070 are formed by the same film layer manufacturing process (that is, the same film layer manufacturing process), that is, the bottom electrode resonance portion 1042, the bottom electrode protrusion portion 1041 and the bottom electrode overlap portion 1040 are integrated
  • the fabricated film layer, the top electrode resonant portion 1071 and the top electrode lap portion 1070 are integrally fabricated, which can simplify the process and reduce the cost.
  • the film material of the 1041 and the bottom electrode overlap portion 1040 and the film material used to make the top electrode resonator portion 1071 and the top electrode overlap portion 1070 can use any suitable conductive material or semiconductor material known in the art, respectively,
  • the conductive material may be a metal material with conductive properties, for example, aluminum (Al), copper (Cu), platinum (Pt), gold (Au), molybdenum (Mo), tungsten (W), iridium (Ir), One or more of osmium (Os), rhenium (Re), palladium (Pd), rhodium (Rh), and ruthenium (Ru).
  • the semiconductor material is for example Si, Ge, SiGe, SiC, SiGeC, etc.
  • the bottom electrode resonance portion 1042, the bottom electrode protrusion portion 1041, and the bottom electrode lap portion 1040 can also be formed by using different film production processes under the premise that the process cost and process technology allow.
  • the top electrode resonance portion 1071 and the top electrode overlap portion 1070 can be formed by using different film production processes.
  • the bottom electrode protrusion 1041 extends on more continuous sides of the bottom electrode resonance portion 1042, and when the bottom electrode protrusion 1041 and the top electrode layer 107 (including When the top electrode overlap portion 1070 or the top electrode resonance portion 1071) overlap in the vertical direction, there is a gap between the bottom electrode protrusion 1041 and the top electrode layer 107 in the vertical direction without interlayer contact. For example, referring to FIG.
  • the piezoelectric resonant layer 1051, the top electrode resonant portion 1071, and the bottom electrode resonant portion 1042 are all pentagonal planar structures, and the area of the piezoelectric resonant layer 1051 is the smallest, followed by the top electrode resonant portion 1071 , The bottom electrode resonant portion 1042 has the largest area.
  • the bottom electrode protrusions 1041 are arranged along multiple sides of the bottom electrode resonant portion 1042 and are connected to these sides, and the bottom electrode protrusions 1041 are on the bottom surface of the cavity 102
  • the projection of the top electrode lap 1070 and its connection with the top electrode resonant portion 1071 is exposed on the bottom surface of the cavity 102, so that the bottom electrode protrusion 1041 and the top electrode lap 1070 do not overlap Therefore, the parasitic parameters can be reduced.
  • the bottom electrode protrusion 1041 can surround multiple sides of the bottom electrode resonance portion 1042, the parasitic transverse waves on the corresponding sides of the piezoelectric resonance layer 1051 can be blocked. Further improve the quality factor. For another example, referring to FIG.
  • the piezoelectric resonance layer 1051, the top electrode resonance portion 1071, and the bottom electrode resonance portion 1042 are all pentagonal planar structures, and the area of the piezoelectric resonance layer 1051 is the smallest, and the top electrode resonance portion 1071 and The area and shape of the bottom electrode resonant portion 1042 are the same or substantially the same.
  • the bottom electrode protruding portion 1041 surrounds the bottom electrode resonant portion 1042. Therefore, the bottom electrode protruding portion 1041 is in a closed ring shape, which can be used for the piezoelectric resonant layer 1051. The generated transverse waves of different heights are blocked.
  • the bottom electrode convex portion 1041 extends on more continuous sides of the bottom electrode resonance portion 1042, the bottom electrode convex portion 1041 extends around the peripheral direction of the piezoelectric resonance layer 1051, and the The bottom electrode protrusion 1041 partially surrounds the periphery of the piezoelectric resonance layer 1051 in the peripheral direction of the piezoelectric resonance layer 1051 (as shown in FIG. 2A), or the bottom electrode protrusion 1041 is along the piezoelectric resonance layer 1051.
  • the peripheral direction of is around a circle of the piezoelectric resonance layer 1051 (as shown in FIG. 2B).
  • the bottom electrode lap portion 1040 is electrically connected to at least one side or at least one side of the bottom electrode protrusion 1041 facing away from the bottom electrode resonance portion 1042 Angle, and extend from the corresponding side of the bottom electrode protrusion 1041 over the cavity (that is, 102B) outside the bottom electrode protrusion 1041 to the part of the periphery of the cavity 102 for etching protection Above the layer 101; the top electrode lap portion 1070 is electrically connected to at least one side or at least one corner of the top electrode resonance portion 1071, and is suspended from the top electrode resonance portion 1071 in the top electrode resonance portion
  • the outer cavity of 1071 (ie 102B) extends above the part of the etching protection layer 101 on the periphery of the cavity 102, and the top electrode overlap portion 1070 and the bottom electrode overlap portion 1040 are in the cavity.
  • the projections on the bottom surface of the cavity 102 may be directly connected or separated from each other. Therefore, the top electrode overlapping portion 1070 and the bottom electrode overlapping portion 1040 do not overlap in the cavity 102 area and are mutually staggered. For example, as shown in FIGS.
  • the bottom electrode overlap portion 1040 may only extend above a part of the substrate around one side of the cavity 102, and the top electrode overlap portion 1070 may only extend to the A part of the periphery of one side of the cavity 102 is above the substrate, and the projections of the top electrode overlap portion 1070 and the bottom electrode overlap portion 1040 on the bottom surface of the cavity 102 are separated from each other, thereby avoiding
  • parasitic parameters and possible problems such as leakage and short circuit are introduced.
  • parasitic parameters and possible problems such as leakage and short circuit are introduced.
  • the bottom electrode overlapping portions 1040 protrude along the bottom electrode.
  • the raised portion 1041 is arranged away from all sides of the bottom electrode resonance portion 1042 and continuously extends to the substrate on the periphery of the cavity 102, thereby enabling the bottom electrode overlap portion 1040 to extend to the periphery of the cavity 102 Above part of the substrate in more directions, that is, the bottom electrode overlap portion 1040 completely covers the cavity 102 above the cavity part where it is located, and then is reinforced by laying a large area bottom electrode overlap portion 1040 The supporting force of the film layer of the effective working area 102A prevents the cavity 102 from collapsing.
  • the top electrode overlapping portion 1070 only extends to the cavity 102 Part of the substrate in one direction of the periphery.
  • the top electrode overlap portion 1070 only extends above the substrate on one side of the cavity 102, and the bottom electrode overlaps
  • the portion 1040 extends to the other three sides of the cavity 102, and at this time, the projections of the top electrode overlapping portion 1070 and the bottom electrode overlapping portion 1040 on the bottom surface of the cavity 102 just meet Or separate from each other, that is, at this time, the bottom electrode overlapping portion 1040 completely covers the cavity 102 above the cavity part where it is located, and is in the width direction of the top electrode overlapping portion 1070, and the top electrode
  • the overlap portion 1070 has no overlap, thereby avoiding that the arrangement of the large-area top electrode overlap portion will overlap with the bottom electrode overlap portion and other structures in the vertical direction to introduce excessive parasitic parameters, thereby further improving the electrical performance of the device And reliability.
  • the bottom electrode overlap portion 1040 and the top electrode overlap portion 1070 respectively expose at least one side of the cavity, thereby making At least one end of the bottom electrode resonant portion 1042 and the top electrode resonant portion 1071 connected to the bottom electrode protrusion 1041 are completely suspended, which can help reduce the area of the ineffective region 102B, thereby reducing the generation of ineffective region 102B Parasitic parameters such as parasitic capacitance improve device performance.
  • the bottom electrode protruding portion 1041 is at least offset from the top electrode overlapping portion 1070 above the cavity 102 (that is, the two do not overlap in the cavity area), and the top electrode overlapping portion
  • the 10770 and the bottom electrode overlap portion 1040 above the cavity 102 are staggered with each other, thereby further reducing parasitic parameters such as parasitic capacitance generated in the invalid region 102B and improving device performance.
  • the line widths of the bottom electrode protrusions 1041 are the minimum line widths allowed by the corresponding process, and the horizontal distances between the bottom electrode protrusions 1041 and the effective working area 102A (ie, the piezoelectric resonance layer 1051) are respectively The minimum distance allowed by the corresponding process.
  • the top electrode resonator portion 1071 and the bottom electrode resonator portion 1042 are similar in shape or have the same area, or the area of the bottom electrode resonator portion 1042 is larger than that of the top electrode resonator portion 1071, but the present invention
  • the technical solution is not limited to this.
  • the shapes of the top electrode resonant portion 1071 and the bottom electrode resonant portion 1042 may not be similar, but it is preferable that the shape of the bottom electrode convex portion 1041 is the best. It is preferably adapted to the shape of the piezoelectric resonance layer 1051, which can extend along at least one side of the piezoelectric resonance layer 1051.
  • the area (or line width) of the top electrode overlap portion 1070 can be minimized, and the area (or line width) of the bottom electrode overlap portion 1040 can be minimized. The smallest.
  • An embodiment of the present invention also provides a filter including at least one bulk acoustic wave resonator as described in any of the foregoing embodiments of the present invention.
  • An embodiment of the present invention also provides a radio frequency communication system, including at least one filter according to an embodiment of the present invention.
  • an embodiment of the present invention also provides a method for manufacturing a bulk acoustic wave resonator of the present invention (for example, the bulk acoustic wave resonator shown in FIGS. 1A to 2D), including:
  • the first sacrificial layer is formed on a part of the substrate by etching the substrate to form a groove and filling the groove with material.
  • the realization process includes:
  • a substrate is provided, specifically, a substrate 100 is provided, and an etching protection layer 101 is covered on the substrate 100.
  • the etching protection layer 101 can be formed on the substrate 100 by any suitable process method, such as thermal oxidation, thermal nitridation, thermal oxynitriding, or other heat treatment methods, or chemical vapor deposition, physical vapor deposition, or atomic layer deposition. on. Further, the thickness of the etching protection layer 101 can be set reasonably according to actual device process requirements, and is not specifically limited here.
  • the etching process can be a wet etching or a dry etching process, and a dry etching process is preferably used. Dry etching includes but not limited to reactive ion etching (RIE), ion beam etching, plasma Body etching or laser cutting.
  • RIE reactive ion etching
  • the depth and shape of the second groove 102' depend on the depth and shape of the cavity required for the bulk acoustic wave resonator to be manufactured, and the cross-sectional shape of the second groove 102' is rectangular.
  • the cross section of the second groove 102' may also be any other suitable shape, for example, a circle, an ellipse, or other polygons (such as pentagons, hexagons, etc.) other than rectangles.
  • the first sacrificial layer 103 can be filled in the second groove 102' by vapor deposition, thermal oxidation, spin coating, or epitaxial growth.
  • the first sacrificial layer 103 can be selected as a semiconductor material, dielectric material, or photoresist material that is different from the substrate 100 and the etch protection layer 101.
  • the first sacrificial layer 103 can be Ge, and the first The sacrificial layer 103 may also cover the etching protection layer 101 on the periphery of the groove or the top surface is higher than the top surface of the etching protection layer 101 around the groove; then, through a chemical mechanical planarization (CMP) process, the second The top of a sacrificial layer 103 is planarized to the top surface of the etching protection layer 101, so that the first sacrificial layer 103 is only located in the second groove 102', and the top surface of the first sacrificial layer 103 It is flush with the top surface of the surrounding etching protection layer 101, thereby providing a flat process surface for subsequent processes.
  • CMP chemical mechanical planarization
  • a sacrificial material layer (not shown) can be covered on the first sacrificial layer 103 by a suitable process such as a coating process or a vapor deposition process.
  • the thickness of the sacrificial material layer depends on the thickness of the bottom electrode protrusions formed subsequently.
  • the protrusion height, the material of the sacrificial material layer can be selected from amorphous carbon, photoresist, dielectric materials (such as silicon nitride, silicon oxycarbide, porous materials, etc.) or semiconductor materials (such as polysilicon, amorphous silicon, germanium) ), etc.; then, the sacrificial material layer is patterned by a photolithography process or a photolithography combined etching process to form a sacrificial protrusion 103', and the line width and size of the sacrificial protrusion 103' , The shape and position determine the line width, size, shape and position of the bottom electrode protrusion to be formed later.
  • the longitudinal cross-section of the sacrificial protrusion 103' along XX′ in FIG. 2A is a trapezoid with a narrow upper and a wide bottom, and the sidewall of the sacrificial protrusion 103' is sandwiched between the top surface of the first sacrificial layer 103 angle It is less than 45 degrees, thereby facilitating the deposition of the subsequent bottom electrode material layer, thereby improving the thickness uniformity of the subsequently formed bottom electrode layer in the region of the second groove 102'.
  • the cross-sectional shape of the sacrificial protrusion 103' can also be a spherical cap with a narrow upper and a wide bottom, that is, its longitudinal cross-section along the line XX' of FIG. 1A is an inverted U shape.
  • the horizontal distance between the sacrificial protrusion 103' and the effective working area 102A is preferably the minimum distance allowed by the etching alignment process of the sacrificial protrusion 103', and the line width of the sacrificial protrusion 103' corresponds to The minimum line width allowed by the process.
  • the sacrificial protrusion 103' and the first sacrificial layer 103 can be formed by the same process, for example, the first sacrificial layer 103 is covered on the second groove 102' and the etching protection layer 101 first.
  • the thickness of the first sacrificial layer 103 is not less than the sum of the depth of the second groove 102' and the thickness of the sacrificial protrusion 103'; then, the first sacrificial layer 10 is patterned by an etching process to form only filling
  • the top surface of the remaining part of the first sacrificial layer 103 is flush with the top surface of the etching protection layer 101.
  • a suitable method can be selected according to the material of the bottom electrode to be formed on the surface of the etching protection layer 101, the first sacrificial layer 103, and the sacrificial protrusion 103' Covering the bottom electrode material layer (not shown), for example, the bottom electrode material layer can be formed by magnetron sputtering, vapor deposition or other physical vapor deposition or chemical vapor deposition methods; then, a photolithography process is used to form a definition on the bottom electrode material layer A photoresist layer (not shown) with a bottom electrode pattern is then used as a mask to etch the bottom electrode material layer to form a bottom electrode layer (that is, the remaining bottom electrode material layer) 104, After that, the photoresist layer is removed.
  • the bottom electrode material layer can use any suitable conductive material or semiconductor material well known in the art, where the conductive material can be a metal material with conductive properties, for example, aluminum (Al), copper (Cu), platinum (Pt) , Gold (Au), molybdenum (Mo), tungsten (W), iridium (Ir), osmium (Os), rhenium (Re), palladium (Pd), rhodium (Rh) and ruthenium (Ru) or There are several kinds of semiconductor materials such as Si, Ge, SiGe, SiC, SiGeC, etc.
  • the bottom electrode layer (the remaining bottom electrode material layer) 104 includes a bottom electrode resonant portion 1042 that covers the effective working area 102A formed subsequently, and a bottom electrode bump 1041 that covers the sacrificial bump 103' , From the side of the bottom electrode protrusion 1041 through the surface of the first sacrificial layer 103 to the outside of the second groove 102', the bottom electrode overlap portion 1040 and the bottom electrode resonant portion 1042 on the etching protection layer 101 , The bottom electrode peripheral portion 1043 separated from the bottom electrode protrusions 1041, the bottom electrode peripheral portion 1043 can be connected to the side of the bottom electrode protrusion 1041 away from the bottom electrode resonance portion 1042 to be used as the area to be formed A metal contact of the bulk acoustic wave resonator can also be separated from the bottom electrode overlap portion 1040 to serve as a part of the bottom electrode overlap portion of the adjacent bulk acoustic wave resonator.
  • the outer periphery of the bottom electrode Section 1043 can be omitted.
  • the top-view shape of the bottom electrode resonator portion 1042 may be a pentagon. In other embodiments of the present invention, it may also be a quadrilateral or a hexagon.
  • the bottom electrode protrusion 1041 is provided on the bottom electrode overlap portion 1040 and the bottom electrode.
  • the bottom electrode protrusion 1041 is arranged along at least one side of the bottom electrode resonance part 1042 and is connected to a corresponding side of the bottom electrode resonance part 1042, and the bottom electrode overlap part 1040 is electrically connected to at least one side or at least one corner of the bottom electrode protruding portion 1041 facing away from the bottom electrode resonance portion 1042, and covers the bottom electrode from the corresponding side of the bottom electrode protruding portion 1041
  • the top surface of the first sacrificial layer 103 outside the convex portion 1041 extends to the top surface of the partial etching protection layer 101 outside the second groove 102', that is, the bottom electrode convex portion 1041 extends along the
  • the sides of the bottom electrode resonance portion 1042 are arranged and at least arranged in the area where the bottom electrode overlap portion 1040 and the bottom electrode resonance portion 1042 are aligned.
  • the bottom electrode protrusion 1041 may surround the bottom electrode
  • the resonant part 1042 makes a circle to form a closed-loop structure (please refer to FIG. 2C). It can also be arranged along only one side of the bottom electrode resonant part 1042, or it can be continuous along the bottom electrode resonant part 1042 An open-loop structure with two or more consecutive sides (please refer to Figure 2A-2B, 2D).
  • the shape, line width, and horizontal distance between the bottom electrode protrusion 1041 and the effective working area 102A all depend on the molding process of the sacrificial protrusion 103'.
  • the bottom electrode overlap portion 1040 completely covers the cavity 102 above the cavity portion where it is located, and overlaps with the top electrode in the width direction of the top electrode overlap portion 1070.
  • the connecting portion 1070 has no overlap, so as to improve the supporting force for the subsequent film layer, and try to avoid introducing unnecessary parasitic parameters by overlapping with the top electrode overlapping portion 1070, for example, when the top-view shape of the second groove 102' is rectangular At this time, the bottom electrode overlapping portion 1040 extends to three sides of the rectangle.
  • the bottom electrode resonance part 1042 may be used as an input electrode or an output electrode that receives or provides an electric signal such as a radio frequency (RF) signal.
  • RF radio frequency
  • the bottom electrode protruding portion 1041 and the bottom electrode resonance portion 1042, the bottom electrode overlapping portion 1040 have substantially the same thickness.
  • step S3 first, any suitable method known to those skilled in the art such as chemical vapor deposition, physical vapor deposition or atomic layer deposition can be used to deposit the piezoelectric material layer 105; , Using a photolithography process to form a photoresist layer (not shown) defining a piezoelectric film pattern on the piezoelectric material layer 105, and then use the photoresist layer as a mask to etch the piezoelectric material layer 105, To form the piezoelectric resonance layer 1051, after that, the photoresist layer is removed.
  • any suitable method known to those skilled in the art such as chemical vapor deposition, physical vapor deposition or atomic layer deposition can be used to deposit the piezoelectric material layer 105; , Using a photolithography process to form a photoresist layer (not shown) defining a piezoelectric film pattern on the piezoelectric material layer 105, and then use the photoresist layer as a mask to etch the piezoelectric
  • the piezoelectric material layer 105 may be made of aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO 3 ), quartz (Quartz), potassium niobate (KNbO) 3 ) or lithium tantalate (LiTaO 3 ) and other piezoelectric materials with wurtzite crystal structure and their combinations.
  • the piezoelectric material layer 105 may further include rare earth metals, such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La).
  • Sc scandium
  • Er erbium
  • Y yttrium
  • La lanthanum
  • the piezoelectric material layer 105 may also include transition metals, such as zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). At least one.
  • the piezoelectric material layer 105 remaining after patterning includes a piezoelectric resonance layer 1051 and a piezoelectric peripheral portion 1050 separated from each other.
  • the piezoelectric resonance layer 1051 is located on the bottom electrode resonance portion 1042, exposing the bottom electrode convex portion 1041, and can The bottom electrode resonance part 1042 is completely or partially covered.
  • the shape of the piezoelectric resonant layer 1051 can be the same as or different from the shape of the bottom electrode resonator 1042, and its top-view shape can be a pentagon or other polygons, such as a quadrilateral, a hexagon, a heptagon, or an octagon. ⁇ Shape and so on.
  • a gap can be formed between the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051 to expose the bottom electrode protruding portion 1041 and the first sacrificial layer 103 around the bottom electrode resonance portion 1042, and is further restricted by the formed gap
  • the subsequent formation area of the second sacrificial layer provides a relatively flat process surface for the subsequent formation of the second sacrificial bump.
  • the piezoelectric peripheral portion 1050 can also realize the difference between the subsequently formed top electrode peripheral portion and the previously formed bottom electrode peripheral portion 1043. It also provides a relatively flat process surface for the subsequent formation of the second sacrificial layer and the top
  • step S4 first, the piezoelectric peripheral portion 1050, the piezoelectric resonance layer 1051, and the piezoelectric peripheral portion 1050 and The gap between the piezoelectric resonance layer 1051 covers the second sacrificial layer 106, and the second sacrificial layer 106 can fill the gap between the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051.
  • the material of the second sacrificial layer 106 It can be selected from at least one of amorphous carbon, photoresist, dielectric materials (such as silicon nitride, silicon oxycarbide, porous materials, etc.) or semiconductor materials (such as polysilicon, amorphous silicon, germanium), etc., and the second
  • the material of the sacrificial layer 106 is preferably the same as the material of the first sacrificial layer 103, so that the same sacrificial layer removal process can be used to remove the first sacrificial layer 103 and the second sacrificial layer 106 together, which simplifies the process and reduces the cost;
  • the top of the second sacrificial layer 106 is planarized by a CMP process, so that the second sacrificial layer 106 is only filled in the gap between the piezoelectric peripheral portion 1050 and the piezoelectric resonance layer 1051, and the piezoelectric peripheral portion 1050, The piezoelectric resonance layer 10
  • the second sacrificial layer 106 on the upper surface of the piezoelectric peripheral portion 1050 and the piezoelectric resonant layer 1051 can also be removed by an etch-back process, so that it is only filled in the piezoelectric peripheral portion 1050 and the pressure. In the gap between the electrical resonance layers 1051.
  • step S5 firstly, a suitable method can be selected according to the material of the top electrode to be formed in the piezoelectric peripheral portion 1050, the piezoelectric resonance layer 1051, and the second sacrificial layer 106.
  • the surface is covered with a top electrode material layer (not shown).
  • the top electrode material layer can be formed by magnetron sputtering, vapor deposition or other physical vapor deposition or chemical vapor deposition methods, and the top electrode material layer can be flattened on top, so that The thickness of the top electrode material layer can be uniform at all positions; then, a photoresist layer (not shown) defining a top electrode pattern is formed on the top electrode material layer by a photolithography process, and then the photoresist layer is used as a mask, The top electrode material layer is etched to form a top electrode layer with a flat top (ie a patterned top electrode material layer or the remaining top electrode material layer) 107, and then the photoresist layer is removed.
  • the top electrode material layer can use any suitable conductive material or semiconductor material well known in the art, wherein the conductive material can be a metal material with conductive properties, for example, Al, Cu, Pt, Au, Mo, W, Ir, One or more of Os, Re, Pd, Rh, and Ru, the semiconductor material is for example Si, Ge, SiGe, SiC, SiGeC, etc.
  • the top electrode layer 107 includes a top electrode resonance part 1071 covering the piezoelectric resonance layer 1051 and extends from the top electrode resonance part 1071 to the second sacrificial layer 106 through a part of the top surface of the second sacrificial layer 106.
  • One side is connected to be used as a metal contact of the bulk acoustic wave resonator to be formed in the area, or it can be separated from the top electrode lap 1070 to be a part of the top electrode lap of the adjacent bulk acoustic wave resonator
  • the top electrode peripheral portion 1072 may be omitted.
  • the top electrode resonance portion 1071 may have the same or different shape as the piezoelectric resonance layer 1051 in plan view.
  • the plan view shape is, for example, a pentagon, and its area is preferably larger than the piezoelectric resonance layer 1051, so that the piezoelectric resonance layer 1051
  • the top electrode resonant part 1071 and the bottom electrode resonant part 1042 are completely sandwiched between, which is beneficial to the reduction of the device size and the reduction of parasitic parameters.
  • the shape of the top electrode resonant part 1071 can also be Polygons such as quadrilateral, hexagon, heptagon, or octagon.
  • the top electrode layer 107 may be used as an input electrode or an output electrode that receives or provides electrical signals such as radio frequency (RF) signals.
  • RF radio frequency
  • the top electrode layer 107 when the bottom electrode layer 104 is used as an input electrode, the top electrode layer 107 can be used as an output electrode, and when the bottom electrode layer 104 is used as an output electrode, the top electrode layer 107 can be used as an input electrode, and the piezoelectric resonance layer 1051
  • the electrical signal input through the top electrode resonance portion 1071 or the bottom electrode resonance portion 1042 is converted into a bulk acoustic wave.
  • the piezoelectric resonance layer 1051 converts electrical signals into bulk acoustic waves through physical vibration.
  • the top electrode lap portion 1070 is electrically connected to a side of the top electrode resonance portion 1071 away from the center of the first sacrificial layer 103, and extends from the top electrode resonance portion 1071 through a portion of the top surface of the second sacrificial layer 106 to The part outside the groove 102' etches the top surface of the protective layer 101, and the top electrode overlap portion 1070 and the bottom electrode overlap portion 1040 are staggered (that is, the two do not overlap in the formed cavity 102 area), And the top electrode lap portion 1070 and the bottom electrode lap portion 1040 respectively expose at least one side of the groove 102' (that is, neither the bottom electrode layer nor the top electrode layer will fully cover the cavity), thereby The influence of the film layer around the cavity on the longitudinal vibration generated by the piezoelectric resonance layer can be reduced, and the performance can be improved.
  • the projection of the bottom electrode protrusion 1041 may expose the projection of the top electrode lap portion 1070 .
  • the projections of the top electrode lap portion 1070 and the bottom electrode lap portion 1040 on the bottom surface of the groove 102' just meet (as shown in FIG. 2C) or separate from each other (as shown in FIG. 1A, 2A, and 2B) (Shown), the top electrode lap portion 1070 may only extend above a part of the substrate at the periphery of one side of the groove 102', so as to help reduce parasitic parameters and reduce the area of the invalid region of the cavity. small.
  • step S6 photolithography combined with an etching process or a laser cutting process may be used in the piezoelectric peripheral portion 1050 facing the edge of the groove 102' or the periphery of the device area of the bulk acoustic wave resonator Perforating is performed to form at least one release hole (not shown) capable of exposing part of the first sacrificial layer 103 or part of the second sacrificial layer 106; then, gas and/or liquid medicine are passed into the release hole, The second sacrificial layer 106 and the first sacrificial layer 103 are removed, and the groove is re-emptied to form a cavity 102.
  • release hole not shown
  • the cavity 102 includes the space and top of the groove 102' restricted by the bottom electrode protrusion 1041.
  • the bottom electrode resonator 1042, the piezoelectric resonant layer 1051, and the top electrode resonator 1071 that are suspended above the cavity 102 and stacked in sequence form a monophonic sound film, and the bottom electrode resonator 1042, the piezoelectric resonant layer 1051, the top electrode resonates
  • the part 1071 and the cavity 102 overlapping each other in the vertical direction is the effective area, which is defined as the effective working area 102A.
  • the resonance part 1042 and the top electrode resonate.
  • part 1071 vibration and resonance will occur in the thickness direction (ie longitudinal direction) of the piezoelectric resonance layer 1051 due to the piezoelectric phenomenon generated in the piezoelectric resonance layer 1051.
  • the other region of the cavity 102 is the invalid region 102B.
  • the ineffective region 102B a region that does not resonate due to a piezoelectric phenomenon even when electric energy is applied to the top electrode layer 107 and the bottom electrode layer 104.
  • the monophonic sound film composed of the bottom electrode resonance part 1042, the piezoelectric resonance layer 1051 and the top electrode resonance part 1071 suspended above the effective working area 102A and stacked in sequence can output resonance corresponding to the vibration of the piezoelectric phenomenon of the piezoelectric resonance layer 1051 Frequency radio frequency signal.
  • a bulk acoustic wave is generated by a piezoelectric phenomenon generated in the piezoelectric resonance layer 1051.
  • This transverse wave will be blocked at the bottom electrode protrusion 1041, confining the transverse wave in the effective working area 102A and preventing it from propagating to the air.
  • the acoustic wave loss caused by the propagation of the transverse wave into the film layer on the periphery of the cavity is thereby improved, so that the quality factor of the resonator is improved, and the performance of the device can finally be improved.
  • the top surface of the second sacrificial layer 106 is flush with the top surface of the piezoelectric resonance layer 1051 in this embodiment, the bottom surface and the top surface of the top electrode layer 107 can be made flush. At this time, the top electrode layer 107 extends flat in the global scope.
  • step S6 can be performed after all the film layers above the cavity 102 to be formed are completed. Therefore, the first sacrificial layer 103 and the second sacrificial layer 106 can continue to be used to protect the cavity 102.
  • the space and the layer structure of the bottom electrode layer 104 to the top electrode layer 107 formed thereon are stacked to avoid the risk of cavity collapse when the subsequent process is continued after the cavity 102 is formed.
  • the release hole formed in step S6 may be kept first, so that the release hole can be sealed by a subsequent packaging process such as two-substrate bonding, so that the cavity 102 is closed.
  • step S1 of the method for manufacturing a bulk acoustic wave resonator of the foregoing embodiments the first sacrificial layer is formed on a part of the substrate by etching the substrate to form the groove 102' and filling the groove 102'.
  • the cavity 102 formed in step S6 is a groove structure with the entire bottom recessed in the substrate, but the technical solution of the present invention is not limited to this.
  • the first sacrificial layer 103 protruding on the substrate as a whole can also be formed by film deposition combined with photolithography and etching processes, so that the cavity 102 formed in step S6 is protruding on the entire substrate.
  • step S1 the groove 102' for making the cavity 102 is no longer formed in the provided substrate, but first The first sacrificial layer 103 is covered on the etching protection layer 101 on the surface of the substrate 100; then the first sacrificial layer 103 is patterned by a photolithography combined with etching process, leaving only the first sacrificial layer 103 covering the area 102, Furthermore, the first sacrificial layer 103 is on a part of the substrate.
  • the first sacrificial layer 103 may have a narrow top and a wide bottom structure.
  • the thickness of the first sacrificial layer 103 determines the depth of the cavity 102 to be subsequently formed.
  • the layer 103 and the substrate are covered with a sacrificial material layer for making the sacrificial protrusions 103', and then the sacrificial protrusions 103' are formed on a part of the first sacrificial layer 103 through a process of photolithography and etching.
  • the subsequent steps are exactly the same as the corresponding parts in the method of manufacturing the bulk acoustic wave resonator of the embodiment shown in FIGS. 4A to 4H, and will not be repeated here, except that the bottom electrode peripheral portion 1043 and the bottom electrode are formed.
  • the electrode overlapping portion 1040, the piezoelectric peripheral portion 1050, the top electrode peripheral portion 1072, and the corresponding side walls of the top electrode overlapping portion 1070 need to be deformed to adapt to the protruding first sacrificial layer 103, and the longitudinal cross-sections all become "Z" shaped structure.
  • the part of the top electrode layer 107 located above the cavity 102 is flat and extending, that is, the top electrode lap portion 1070 is located above the cavity (excluding the part corresponding to the sidewall of the first sacrificial layer 103) and the top electrode
  • the top surface of the resonance portion 1071 is flush, and the bottom surface of the top electrode overlapping portion 1070 above the cavity (excluding the part corresponding to the sidewall of the first sacrificial layer 103) is flush with the bottom surface of the top electrode resonance portion 1071.
  • the bulk acoustic wave resonator of the present invention preferably adopts the manufacturing method of the bulk acoustic wave resonator of the present invention, so that the bottom electrode overlap portion, the bottom electrode protrusion portion and the bottom electrode resonator portion are manufactured together, and the top electrode overlap portion and the top electrode The electrode resonance parts are manufactured at one time, thereby simplifying the process and reducing the manufacturing cost.

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

一种体声波谐振器及其制造方法和滤波器、射频通信系统，形成于压电谐振层（1051）外围的且悬空于空腔（102）上方的底电极凸起部（1041），能够阻挡压电谐振层（1051）产生的横波向空腔（102）外围传输，将横波反射回有效工作区（102A）中，继而减少和降低了声波损耗，使谐振器的品质因子得到提高，最终能够提高器件性能。进一步地，底电极搭接部（1040）和顶电极搭接部（1070）与空腔（102）的重叠部分均是悬空的，且底电极搭接部（1040）和顶电极搭接部（1070）相互错开，可以大大降低寄生参数，并避免漏电、短路等问题，能够提高器件可靠性。

Description

体声波谐振器及其制造方法和滤波器、射频通信系统 技术领域
本发明涉及射频通信技术领域，尤其涉及一种体声波谐振器及其制造方法和滤波器、射频通信系统。
背景技术
射频(RF)通信，如在移动电话中使用的通信，需要运用射频滤波器，每一个射频滤波器都能传递所需的频率，并限制所有其他频率。随着移动通信技术的发展，移动数据传输量也迅速上升。因此，在频率资源有限以及应当使用尽可能少的移动通信设备的前提下，提高无线基站、微基站或直放站等无线功率发射设备的发射功率成了必须考虑的问题，同时也意味着对移动通信设备前端电路中滤波器功率的要求也越来越高。
目前，无线基站等设备中的大功率滤波器主要是以腔体滤波器为主，其功率可达上百瓦，但是这种滤波器的尺寸太大。也有的设备中使用介质滤波器，其平均功率可达5瓦以上，这种滤波器的尺寸也很大。由于尺寸大，所以这两种滤波器无法集成到射频前端芯片中。
随着MEMS技术越来越成熟，由体声波(BAW)谐振器构成的滤波器，能够很好地克服了上述两种滤波器存在的缺陷。体声波谐振器具有陶瓷介质滤波器不可比拟的体积优势、声表面波(SAW)谐振器不可比拟的工作频率以及功率容量的优势，成为了当今无线通信系统的发展趋势。
体声波谐振器的主体部分为底电极-压电薄膜-顶电极构成的“三明治”结构，利用压电薄膜的逆压电效应将电能转化成机械能，并以声波的形式在体声波谐振器构成的滤波器中形成驻波。由于声波的速度比电磁波小5个数量级，因此体声波谐振器构成的滤波器的尺寸比传统的介质滤波器等小。
其中一种空腔型体声波谐振器，其工作原理是利用声波在底电极或支撑层与空气的交界面发生反射，将声波限制在压电层，实现谐振，其具有高Q值、低插损、可集成等优点，被广泛采用。
但是，目前制作出的空腔型体声波谐振器，其品质因子(Q)无法进一步提高，因此无法满足高性能的射频系统的需求。
发明内容
本发明的目的在于提供一种体声波谐振器及其制造方法和滤波器、射频通信系统，能够提高品质因子，进而提高器件性能。
为了实现上述目的，本发明提供一种体声波谐振器包括：
衬底；
底电极层，设置在所述衬底上，且所述底电极层和所述衬底之间形成有空腔，所述底电极层具有底电极凸起部，所述底电极凸起部位于所述空腔的区域中且向着远离近所述空腔的底面的方向凸起；
压电谐振层，形成在所述空腔上方的所述底电极层上，所述底电极凸起部围绕所述压电谐振层的周边方向延伸并被所述压电谐振层暴露出来；
顶电极层，形成在所述压电谐振层上，且所述顶电极层位于所述空腔上方的部分是平坦延伸的。
本发明还提供一种滤波器，包括至少一个如本发明所述的体声波谐振器。
本发明还提供一种射频通信系统，包括至少一个如本发明所述的滤波器。
本发明还提供一种体声波谐振器的制造方法，包括：
提供衬底，形成具有牺牲凸起的第一牺牲层于部分所述衬底上；
形成底电极层于所述第一牺牲层上，所述底电极层覆盖在所述牺牲凸起的表面上的部分形成底电极凸起部；
形成压电谐振层于所述底电极层上，所述底电极凸起部围绕所述压电谐振层的周边方向延伸且被所述压电谐振层暴露出来；
形成第二牺牲层于所述压电谐振层周围暴露出的区域中，所述第二牺牲层和所述压电谐振层的顶面齐平；
形成顶电极层于所述压电谐振层及压电谐振层周围的部分第二牺牲层上；
去除所述第二牺牲层和具有所述牺牲凸起的所述第一牺牲层，所述第二牺牲层和所述第一牺牲层的位置形成空腔，所述底电极凸起部位于所述压电谐振层外围的空腔区域中，且所述顶电极层位于所述空腔上方的部分是平坦延伸的。
与现有技术相比，本发明的技术方案，具有以下有益效果：
1、当电能施加到底电极和顶电极时，通过在压电谐振层中产生的压电现象而产生期望的沿着厚度方向传播的纵波以及不期望的沿着压电谐振层平面传播 的横波，该横波会在悬空于压电谐振层外围的空腔上的底电极凸起部处受到阻挡，被反射回压电谐振层所对应的区域中，继而减少和降低了横波传播到空腔外围的膜层中时造成的损失，由此改善声波损耗，使谐振器的品质因子得到提高，最终能够提高器件性能。
2、压电谐振层的周边与空腔的周边相互分离，即压电谐振层不会连续延伸到空腔外围的衬底上方，能够将体声波谐振器的有效工作区完全限制在空腔区域中，且底电极搭接部和顶电极搭接部均只会延伸到空腔外围的部分衬底的上方(即底电极层和顶电极层均不会对空腔全面覆盖)，由此能够减少空腔周围的膜层对压电谐振层产生的纵向振动的影响，提高性能。
3、底电极凸起部和顶电极搭接部即使有相互重叠的部分，重叠的部分之间也是空隙结构，由此可以大大降低寄生参数，并避免顶电极层和底电极层在空腔区域中的电接触等问题，能够提高器件可靠性。
4、底电极搭接部和顶电极搭接部与空腔的重叠部分均是悬空的，且底电极搭接部和顶电极搭接部在空腔的区域中相互错开，由此可以大大降低寄生参数，并避免底电极搭接部和顶电极搭接部相接触而引起的漏电、短路等问题，能够提高器件可靠性。
5、所述底电极搭接部在自身所处的空腔部分上方完全遮盖空腔，由此，可以利用大面积的底电极搭接部来对其上方的膜层进行强有力的机械支撑，从而避免因空腔坍塌而器件失效的问题。
6、底电极凸起部围绕底电极谐振部一周，可以从压电谐振层的周边全方位的阻挡横波，进而获得较佳的品质因子。
7、底电极凸起部、底电极谐振部和底电极搭接部采用同一膜层形成，且膜厚均匀，顶电极谐振部和顶电极搭接部采用同一膜层形成，且膜厚均匀，由此能够简化工艺，降低成本，且因为底电极凸起部的膜厚与底电极层的其他部分基本相同，因此不会出现底电极凸起部断裂的情况，能够提高器件的可靠性。
8、顶电极层位于空腔区域上方的部分是平坦延伸的，一方面能够有利于提高有效区中的薄膜的厚度均一性，另一方面为后续工艺提供平坦的工艺表面，以避免后续的膜层刻蚀工艺因顶电极层在空腔区域的顶面不平而出现刻蚀残留的问题，从而减小寄生参数。
附图说明
图1A是本发明一实施例的体声波谐振器的俯视结构示意图。
图1B和图1C是沿图1中的XX’和YY’线的剖面结构示意图。
图2A至图2C是本发明其他实施例的体声波谐振器的俯视结构示意图。
图2D是本发明其他实施例的体声波谐振器的剖面结构示意图。
图3是本发明一实施例的体声波谐振器的制造方法的流程图。
图4A至图4G是本发明一实施例的体声波谐振器的制造方法中沿图1A中的XX’的剖面示意图。
图5是本发明另一实施例的体声波谐振器的制造方法中沿图1A中的XX’的剖面示意图。
其中，附图标记如下：
100-基底；101-刻蚀保护层；102-空腔；102’-凹槽；102A-有效工作区；102B-无效区；103-第一牺牲层；103’-牺牲凸起；104-底电极层(即剩余的底电极材料层)；1040-底电极搭接部；1041-底电极凸起部；1042-底电极谐振部；1043-底电极外围部；105-压电材料层；1050-压电外围部；1051-压电谐振层(或称为压电谐振部)；106-第二牺牲层；107-顶电极层(即剩余的顶电极材料层)；1070-顶电极搭接部；1071-顶电极谐振部；1072-顶电极外围部。
具体实施方式
以下结合附图和具体实施例对本发明的技术方案作进一步详细说明。根据下面的说明，本发明的优点和特征将更清楚。需说明的是，附图均采用非常简化的形式且均使用非精准的比例，仅用以方便、明晰地辅助说明本发明实施例的目的。类似的，如果本文所述的方法包括一系列步骤，且本文所呈现的这些步骤的顺序并非必须是可执行这些步骤的唯一顺序，且一些所述的步骤可被省略和/或一些本文未描述的其他步骤可被添加到该方法。另外本文中的某物与某物“相互错开”的含义是两者在空腔区域不重叠，即两者向空腔的底面上的投影不重叠。
请参考图1A至图1C，图1A为本发明一实施例的体声波谐振器的俯视结构示意图，图1B是沿图1中的XX’的剖面结构示意图，图1C是沿图1A中的YY’线的剖面结构示意图，本实施例的体声波谐振器包括：衬底、底电极层104、 压电谐振层1051和顶电极层107。
其中，所述衬底包括基底100以及覆盖在所述基底100上的刻蚀保护层101。所述基底100可以为本领域技术人员熟知的任意合适的底材，例如可以是以下所提到的材料中的至少一种：硅(Si)、锗(Ge)、锗硅(SiGe)、碳硅(SiC)、碳锗硅(SiGeC)、砷化铟(InAs)、砷化镓(GaAs)、磷化铟(InP)或者其它III/V化合物半导体，还包括这些半导体构成的多层结构等，或者为绝缘体上硅(SOI)、绝缘体上层叠硅(SSOI)、绝缘体上层叠锗化硅(S-SiGeOI)、绝缘体上锗化硅(SiGeOI)以及绝缘体上锗(GeOI)，或者还可以为双面抛光硅片(Double Side Polished Wafers，DSP)，也可为氧化铝等的陶瓷基底、石英或玻璃基底等。所述刻蚀保护层101的材料可以是任意适合的介电材料，包括但不限于氧化硅、氮化硅、氮氧化硅、碳氮化硅等材料中的至少一种，该刻蚀保护层一方面可以用于增加最终制造的体声波谐振器的结构稳定性，增加了体声波谐振器与基底100之间的隔离，可以降低对基底100的电阻率要求，另一方面还以在制造体声波谐振器的过程中保护衬底其他区域不受刻蚀，从而提高器件性能与可靠性。
底电极层104和衬底之间形成有空腔102。请参考图1A至图1C，在本实施例中，所述空腔102可以通过刻蚀工艺依次刻蚀所述刻蚀保护层101和部分厚度的基底100而形成，成为一个整个底部凹陷在所述衬底中的凹槽结构。但本发明的技术不仅仅限定于此，请参考图2D，在本发明的另一实施例中，所述空腔102也可以采用将凸设于刻蚀保护层101表面上的牺牲层通过后去除方法去除的工艺形成在刻蚀保护层101的顶面上方，成为一个整体上凸设在所述刻蚀保护层101表面上的腔体结构。此外，本实施例中，空腔102的底面的形状为矩形，但在本发明的其他实施例中，空腔102的底面形状还可以是圆形、椭圆形或是矩形以外的多边形，例如五边形、六边形等。
压电谐振层1051也可以称为压电谐振部，位于所述空腔102的上方区域中(也可以说是位于所述空腔102的区域中)，对应体声波谐振器的有效工作区，且压电谐振层1051设置在底电极层104和顶电极层107之间。底电极层104包括依次连接的底电极搭接部1040、底电极凸起部1041以及底电极谐振部1042，顶电极层107包括依次连接的顶电极搭接部1070以及顶电极谐振部1071，底电极谐振部1042、顶电极谐振部1071均与压电谐振层1051重叠，且所述空腔102与重叠在一起的底电极谐振部1042、压电谐振层1051、顶电极谐振部1071对 应的区域构成所述体声波谐振器的有效工作区102A，空腔102除有效工作区102A以外的部分为无效区102B，压电谐振层1051位于有效工作区102A中并与空腔102周围的膜层分离，能够将体声波谐振器的有效工作区完全限制在空腔102的区域中，并能够减少空腔周围的膜层对压电谐振层产生的纵向振动的影响，降低无效区102B中产生的寄生参数，提高器件性能。底电极谐振部1042、压电谐振层1051、顶电极谐振部1071均为上下表面是平面的平坦结构，所述底电极凸起部1041位于所述有效工作区102A外围的空腔102B上方并电连接所述底电极谐振部1042，且向着远离所述空腔的底面的方向凸起，底电极凸起部1041整体上低于底电极谐振部1042的顶面。底电极凸起部1041可以是实心结构，也可以是空心结构，优选为空心结构，由此能使得底电极层104的膜厚均匀，避免实心的底电极凸起部1041的重力引起底电极谐振部1042和压电谐振层1051分离，继而进一步改善谐振因子。其中，所述底电极谐振部1042、所述顶电极谐振部1071均为多边形(顶面和底面均为多边形)，且所述底电极谐振部1042、所述顶电极谐振部1071的形状可以相似(如图2A～2B以及2D所示)或者完全相同(如图1A和图2C所示)。压电谐振层1051为与所述底电极谐振部1042、所述顶电极谐振部1071的形状相似的多边形结构。顶电极层107位于所述空腔102上方的部分是平坦延伸的，即顶电极搭接部1070位于空腔上方的部分的顶面和所述顶电极谐振部1071的顶面齐平，顶电极搭接部1070位于空腔上方的部分的底面和所述顶电极谐振部1071的底面齐平。
请参考图1A至图1C，在本实施例中，底电极层104、压电谐振层1051以及顶电极层107构成一个“手表”形状的膜层结构，底电极搭接部1040和底电极谐振部1042的一个角对齐，顶电极搭接部10740和顶电极谐振部1071的一个角对齐，底电极搭接部1040和顶电极搭接部1070相当于“手表”的两个表带，所述底电极凸起部1041沿着所述底电极谐振部1042的边设置且仅设置在所述底电极搭接部1040和所述底电极谐振部1042对齐的区域中，所述底电极凸起部1041相当于“手表”的表盘与一个表带之间的连接结构，有效区102A中的底电极谐振部1042、压电谐振层1051、顶电极谐振部1071堆叠结构相当于手表的表盘，该表盘除了表带部分与空腔周围衬底上的膜层相接外，其余部分均通过空腔与空腔周围衬底上的膜层相分离。即本实施例中，所述底电极凸起部1041围绕所述压电谐振层1051的周边方向延伸，且所述底电极凸起部1041 沿压电谐振层1051的周边方向围绕在压电谐振层1051的部分边上，且以压电谐振层1051所在的平面为参考，所述顶电极搭接部1070和所述底电极凸起部1041分居压电谐振层1051两侧且完全相对，所述顶电极搭接部1070和所述底搭接部1040分居压电谐振层1051两侧且完全相对，由此在实现一定的横波阻挡效果的同时，能够有利于顶电极搭接部1070和底电极搭接部1040未覆盖的无效区102B的面积的减小，进而有利于器件尺寸的减小，同时还有利于减小顶电极搭接部1070和底电极搭接部1040的面积，以进一步减少寄生参数，提高器件的电学性能。所述底电极搭接部1040电连接所述底电极凸起部1041背向所述底电极谐振部1042的一侧，并从所述底电极凸起部1041上经悬空于所述底电极凸起部1041外侧的空腔(即102B)上方后延伸到所述空腔102外围的部分刻蚀保护层101的上方；所述顶电极搭接部1070电连接所述顶电极谐振部1071的一侧，并从所述顶电极谐振部1071上经悬空于所述顶电极谐振部1071外侧的空腔(即102B)上方后延伸到所述空腔102外围的部分刻蚀保护层101上方；所述底电极搭接部1040和所述顶电极搭接部1070延伸到所述空腔102的两相对的边外侧的衬底上方，此时所述底电极搭接部1040和所述顶电极搭接部1070在空腔102区域中相互错开(即二者不重叠)，由此，可以降低寄生参数，并避免底电极层104和顶电极层107相接触而引起的漏电、短路等问题，提高器件性能。所述底电极搭接部1040可以用于连接相应的信号线，以通过底电极凸起部1041向底电极谐振部1042传递相应的信号，所述顶电极搭接部1070可以用于连接相应的信号线，以向顶电极谐振部1071传递相应的信号，从而使得体声波谐振器可以正常工作，具体地，通过底电极搭接部1040、顶电极搭接部1070分别向底电极谐振部1042和顶电极谐振部1071施加时变电压来激发纵向延伸模式或“活塞”模式，压电谐振层1051将电能形式的能量转换成纵波，在此过程中会产生寄生的横波，底电极凸起部1041可以阻挡这些横波向空腔外围的膜层中传播，将其限制在空腔102的区域内，从而避免横波引起的能量损耗，提高品质因子。
优选地，底电极凸起部1041的线宽为对应的工艺所允许的最小线宽，底电极凸起部1041与压电谐振层1051之间的水平距离为对应的工艺所允许的最小距离，由此在使得底电极凸起部1041能够实现一定的横波阻挡效果的同时，能有利于减小器件面积。
此外，所述底电极凸起部1041的侧壁相对所述压电谐振层的底面为倾斜侧壁，如图1B所示，所述底电极凸起部1041沿图1A中XX’线的截面为梯形或类梯形，所述底电极凸起部1041的两个侧壁与所述压电谐振层1051的底面之间的夹角α1、α2均小于等于45度，由此，避免因所述底电极凸起部1041的侧壁过于竖直而造成底电极层104断裂，进而影响向底电极谐振部1042上传输信号的效果，同时还能够提高底电极层104的厚度均一性。
在本发明的一个优选实施例中，底电极谐振部1042、底电极凸起部1041以及底电极搭接部1040采用同一膜层的制作工艺(即同一道膜层制作工艺)形成，顶电极谐振部1071以及顶电极搭接部1070采用同一膜层的制作工艺(即同一道膜层制作工艺)形成，即底电极谐振部1042、底电极凸起部1041和底电极搭接部1040为一体式制作的膜层，顶电极谐振部1071和顶电极搭接部1070为一体式制作的膜层，由此可以简化工艺，降低成本，其中，用于制作底电极谐振部1042、底电极凸起部1041和底电极搭接部1040的膜层材料和用于制作顶电极谐振部1071和顶电极搭接部1070的膜层材料可以分别使用本领域技术任意熟知的任意合适的导电材料或半导体材料，其中，导电材料可以为具有导电性能的金属材料，例如，铝(Al)、铜(Cu)、铂金(Pt)、金(Au)、钼(Mo)、钨(W)、铱(Ir)、锇(Os)、铼(Re)、钯(Pd)、铑(Rh)及钌(Ru)中的一种或几种，所述半导体材料例如Si、Ge、SiGe、SiC、SiGeC等。当然在本发明的其他实施例中，在工艺成本和工艺技术允许的前提下，底电极谐振部1042、底电极凸起部1041以及底电极搭接部1040也可以采用不同的膜层制作工艺形成，顶电极谐振部1071以及顶电极搭接部1070可以采用不同的膜层制作工艺形成。
请参考图2A至图2C，为了进一步提高横波阻挡效果，底电极凸起部1041延伸到底电极谐振部1042的更多连续的边上，且当底电极凸起部1041和顶电极层107(包括顶电极搭接部1070或顶电极谐振部1071)在垂直方向上有重叠时，底电极凸起部1041和顶电极层107在垂直方向上有间隙而不会发生层间接触。例如，请参考图2A，压电谐振层1051、顶电极谐振部1071以及底电极谐振部1042均为五边形的平面结构，且压电谐振层1051的面积最小，顶电极谐振部1071次之，底电极谐振部1042的面积最大，所述底电极凸起部1041沿底电极谐振部1042的多个边设置并连接到这些边上，且底电极凸起部1041在空腔102的底面上的投影暴露所述顶电极搭接部1070及其与顶电极谐振部1071 连接处在空腔102的底面上的全部投影，由此使得底电极凸起部1041与顶电极搭接部1070不重叠，进而可以降低寄生参数，此外，由于底电极凸起部1041能够对底电极谐振部1042的多个边进行包围，因此可以对压电谐振层1051的相应的边上的寄生横波进行横波阻挡，进一步提高品质因子。再例如，请参考图2B，压电谐振层1051、顶电极谐振部1071以及底电极谐振部1042均为五边形的平面结构，且压电谐振层1051的面积最小，顶电极谐振部1071和底电极谐振部1042的面积、形状等相同或基本相同，底电极凸起部1041包围底电极谐振部1042的一周,由此底电极凸起部1041呈封闭的环形，可以对压电谐振层1051产生的不同高度的横波进行阻挡。也就是说，当底电极凸起部1041延伸到底电极谐振部1042的更多连续的边上时，所述底电极凸起部1041围绕所述压电谐振层1051的周边方向延伸，且所述底电极凸起部1041沿压电谐振层1051的周边方向对压电谐振层1051的周边进行部分围绕(如图2A所示)，或者，所述底电极凸起部1041沿压电谐振层1051的周边方向围绕压电谐振层1051的一周(如图2B所示)。
请参考图2A至2C，在本发明的这些实施例中，所述底电极搭接部1040电连接所述底电极凸起部1041背向所述底电极谐振部1042的至少一个边或至少一个角，并从所述底电极凸起部1041的相应边上经悬空于所述底电极凸起部1041外侧的空腔(即102B)上方后延伸到所述空腔102外围的部分刻蚀保护层101的上方；所述顶电极搭接部1070电连接所述顶电极谐振部1071的至少一个边或至少一个角，并从所述顶电极谐振部1071上经悬空于所述顶电极谐振部1071外侧的空腔(即102B)上方后延伸到所述空腔102外围的部分刻蚀保护层101上方，且所述顶电极搭接部1070和所述底电极搭接部1040在所述空腔102的底面上的投影可以正好相接，也可以相互分离，由此，所述顶电极搭接部1070和所述底电极搭接部1040在空腔102的区域上无重叠而相互错开。例如图1A、图2A～2B所示，底电极搭接部1040可以仅延伸到所述空腔102的一条边外围的部分衬底的上方，所述顶电极搭接部1070仅延伸到所述空腔102的一条边外围的部分衬底的上方，且所述顶电极搭接部1070和所述底电极搭接部1040在所述空腔102的底面上的投影相互分离，由此避免所述顶电极搭接部1070和所述底电极搭接部1040重叠时引入寄生参数以及有可能引起的漏电、短路等问题。但优选地，请参考图2C，当所述底电极凸起部1041沿着所述底电极谐振部1042 的连续多条边设置时，所述底电极搭接部1040沿着所述底电极凸起部1041背向所述底电极谐振部1042的所有边设置并连续延伸到所述空腔102外围的衬底上，由此使得底电极搭接部1040能够延伸到所述空腔102外围的更多方向上的部分衬底的上方，即所述底电极搭接部1040在自身所处的空腔部分上方完全遮盖空腔102，进而通过大面积的底电极搭接部1040的铺设来增强对有效工作区102A的膜层的支撑力，防止空腔102的坍塌。进一步优选地，当所述底电极搭接部1040延伸到所述空腔102外围的更多方向上的部分衬底的上方时，所述顶电极搭接部1070仅延伸到所述空腔102外围的一个方向上的部分衬底的上方，例如空腔102的俯视形状为矩形时，所述顶电极搭接部1070仅延伸到空腔102的一条边外围的衬底上方，底电极搭接部1040延伸到与所述空腔102的另外三条边上，且此时所述顶电极搭接部1070和所述底电极搭接部1040在所述空腔102的底面上的投影正好相接或相互分离，即此时，所述底电极搭接部1040在自身所处的空腔部分上方完全遮盖空腔102，且在所述顶电极搭接部1070的宽度方向，与所述顶电极搭接部1070无重叠，由此避免大面积顶电极搭接部的设置会与底电极搭接部等结构在垂直方向上发生重叠而引入过多的寄生参数，进而可以进一步提高器件的电学性能和可靠性。
在本发明的各个实施例中，当所述空腔102的俯视形状为多边形时，底电极搭接部1040和顶电极搭接部1070分别暴露出所述空腔的至少一个边，由此使得连接有底电极凸起部1041的底电极谐振部1042和顶电极谐振部1071分别有至少一端是完全悬空的，这样可以有利于减小无效区102B的面积，进而减小无效区102B中产生的寄生电容等寄生参数，提高器件性能。优选地，所述底电极凸起部1041在所述空腔102上方至少与所述顶电极搭接部1070相互错开(即二者在空腔区域不重叠)，所述顶电极搭接部部10770在所述空腔102上方至少与所述底电极搭接部1040相互错开，由此进一步降低无效区102B中产生的寄生电容等寄生参数，提高器件性能。
需要说明的是，为了达到最好的横波阻挡效果且有利于小尺寸器件的制作，底电极凸起部1041越靠近有效工作区102A越好，底电极凸起部1041的线宽越小越好，优选地，底电极凸起部1041的线宽分别为对应的工艺所允许的最小线宽，底电极凸起部1041与有效工作区102A(即与压电谐振层1051)的水平距离分别为对应的工艺所允许的最小距离。
值得注意的是，上述各实施例中，顶电极谐振部1071和底电极谐振部1042形状相似或相同且面积相同，或底电极谐振部1042面积大于顶电极谐振部1071的面积，但是本发明的技术方案并不仅仅限定于此，在本发明的其他实施例中，顶电极谐振部1071和底电极谐振部1042的形状也可以不相似，但是优选的是，底电极凸起部1041的形状最好是与压电谐振层1051的形状相适配，其能够沿压电谐振层1051的至少一个边延伸。另外，经我们研究发现，体声波谐振器的寄生横波大部分会通过有效工作区102A上的膜层与空腔外围的衬底之间的连接结构来传递，因此本发明各实施例中，在保证能够对有效工作区102A的膜层进行有效支撑的前提下，可以尽量控制顶电极搭接部1070的面积(或者说线宽)最小，底电极搭接部1040的面积(或者说线宽)最小。
本发明一实施例还提供一种滤波器，包括至少一个如上述的任意本发明实施例所述的体声波谐振器。
本发明一实施例还提供一种射频通信系统，包括至少一个如本发明一实施例所述的滤波器。
请参考图3，本发明一实施例还提供一种本发明的体声波谐振器(例如图1A至图2D所示的体声波谐振器)的制造方法，包括：
S1，提供衬底，形成具有牺牲凸起的第一牺牲层于部分所述衬底上；
S2，形成底电极层于所述第一牺牲层上，所述底电极层覆盖在所述牺牲凸起的表面上的部分形成底电极凸起部；
S3，形成压电谐振层于所述底电极层上，所述底电极凸起部围绕所述压电谐振层的周边方向延伸且被所述压电谐振层暴露出来；
S4，形成第二牺牲层于所述压电谐振层周围暴露出的区域中，所述第二牺牲层和所述压电谐振层的顶面齐平；
S5，形成顶电极层于所述压电谐振层及压电谐振层周围的部分第二牺牲层上；
S6，去除所述第二牺牲层和具有所述牺牲凸起的所述第一牺牲层，所述第二牺牲层和所述第一牺牲层的位置形成空腔，所述底电极凸起部位于所述压电谐振层外围的空腔区域中，且所述顶电极层位于所述空腔上方的部分是平坦延伸的。
请参考图1A、1B和图4A至4B，在本实施例的步骤S1中，通过刻蚀衬底 形成凹槽以及向凹槽中填充材料的工艺形成第一牺牲层于部分衬底上，具体实现过程包括：
首先，请参考图1A和图4A，提供衬底，具体地，提供一基底100，并在基底100上覆盖刻蚀保护层101。其中，所述刻蚀保护层101可以通过任意适合的工艺方法例如热氧化、热氮化、热氧氮化等热处理方法或者化学气相沉积、物理气相沉积或原子层沉积等沉积方法形成于基底100上。进一步地，刻蚀保护层101的厚度可以根据实际器件工艺需要进行合理设定，在此不做具体限定。
接着，请继续参考图1A、1B和图4A，通过光刻和刻蚀工艺，对衬底进行刻蚀，以形成至少一个第二凹槽102’。该刻蚀工艺可以是湿法刻蚀或者干法刻蚀工艺，其中较佳地使用干法刻蚀工艺，干法刻蚀包括但不限于反应离子刻蚀(RIE)、离子束刻蚀、等离子体刻蚀或者激光切割。第二凹槽102’的深度和形状均取决于待制造的体声波谐振器所需空腔的深度和形状，第二凹槽102’的横截面形状为矩形，在本发明的其他实施例中，第二凹槽102’的横截面还可以是其他任意合适的形状，例如是圆形、椭圆形或者矩形除外的其他多边形(如五边形、六边形等)。
然后，请参考图1A、1B和图4B，可以通过气相沉积、热氧化、旋涂或外延生长等工艺填充第一牺牲层103于所述第二凹槽102’中，所述第一牺牲层103可以选取为不同于基底100和刻蚀保护层101的半导体材料、介电材料或光阻材料等，例如当基底100为Si基底，第一牺牲层103可以为Ge，此时形成的第一牺牲层103可能还覆盖在凹槽外围的刻蚀保护层101上或者顶面高于凹槽周围的刻蚀保护层101顶面；然后，通过化学机械平坦化(CMP)工艺，将所述第一牺牲层103的顶部平坦化至所述刻蚀保护层101的顶面，以使得所述第一牺牲层103仅位于第二凹槽102’中，且所述第一牺牲层103的顶面与其周围的刻蚀保护层101的顶面齐平，由此为后续工艺提供平坦的工艺表面。
接着，可以通过涂覆工艺或者气相沉积工艺等合适的工艺，在第一牺牲层103上覆盖牺牲材料层(未图示)，该牺牲材料层的厚度取决于后续形成的底电极凸起部的凸出高度，该牺牲材料层的材料可以选自非晶碳、光刻胶、介电材料(例如氮化硅、碳氧化硅、多孔材料等)或半导体材料(例如多晶硅、非晶硅、锗)等中的至少一种；然后，通过光刻工艺或者光刻结合刻蚀的工艺，将所述牺牲材料层进行图案化，形成牺牲凸起103’，牺牲凸起103’的线宽、大小、 形状以及位置决定了后续形成的底电极凸起部的线宽、大小、形状以及位置。本实施例中，牺牲凸起103’沿图2A的XX’的纵向截面均为上窄下宽的梯形，且牺牲凸起103’的侧壁与第一牺牲层103的顶面之间的夹角
Figure PCTCN2019105096-appb-000001
小于45度，由此，有利于后续底电极材料层的沉积，进而提高后续形成的底电极层在第二凹槽102’区域内的厚度均一性。在本发明的其他实施例中，牺牲凸起103’的截面形状还可以是上窄下宽的球冠，即其沿图1A的XX’线的纵向截面均为倒U形。所述牺牲凸起103’与所述有效工作区102A之间的水平距离优选为牺牲凸起103’刻蚀对准的工艺所允许的最小距离，所述牺牲凸起103’的线宽为对应的工艺所允许的最小线宽。
在本发明的其他实施例中，牺牲凸起103’和第一牺牲层103可以通过同一道工艺形成，例如，先在第二凹槽102’和刻蚀保护层101上覆盖第一牺牲层103，该第一牺牲层103的厚度不小于第二凹槽102’的深度以及牺牲凸起103’的厚度之和；然后，通过刻蚀工艺对第一牺牲层10进行图案化，以形成仅填充在第二凹槽102’中的第一牺牲层103，且部分第一牺牲层103具有牺牲凸起103’，该牺牲凸起103’的底面可以齐平于所述刻蚀保护层101的顶面，其余部分的第一牺牲层103的顶面齐平于所述刻蚀保护层101的顶面。
请参考图1A、1B和4D，在步骤S2中，首先，可以根据预定形成的底电极的材料选择适合的方法在刻蚀保护层101、第一牺牲层103以及牺牲凸起103’的表面上覆盖底电极材料层(未图示)，例如可以通过磁控溅射、蒸镀等物理气相沉积或者化学气相沉积方法形成底电极材料层；然后，利用光刻工艺在底电极材料层上形成定义有底电极图案的光刻胶层(未图示)，再以光刻胶层为掩膜，刻蚀所述底电极材料层，以形成底电极层(即剩余的底电极材料层)104，之后，将光刻胶层去除。底电极材料层可以使用本领域技术任意熟知的任意合适的导电材料或半导体材料，其中，导电材料可以为具有导电性能的金属材料，例如，铝(Al)、铜(Cu)、铂金(Pt)、金(Au)、钼(Mo)、钨(W)、铱(Ir)、锇(Os)、铼(Re)、钯(Pd)、铑(Rh)及钌(Ru)中的一种或几种，所述半导体材料例如Si、Ge、SiGe、SiC、SiGeC等。本实施例中，底电极层(剩余的底电极材料层)104包括覆盖在后续形成的有效工作区102A上的底电极谐振部1042、覆盖在牺牲凸起103’上的底电极凸起部1041、从底电极凸起部1041的一侧经第一牺牲层103的表面延伸到第二凹槽102’外侧的部分刻蚀保护层101上的底电极搭接部1040以及与 底电极谐振部1042、底电极凸起部1041均分离的底电极外围部1043，该底电极外围部1043可以与底电极凸起部1041背向底电极谐振部1042的一侧连接，以用做该区域待形成的体声波谐振器的一个金属接点，也可以与底电极搭接部1040分离，以作为相邻的体声波谐振器的底电极搭接部的一部分，在本发明的其他实施例中，底电极外围部1043可以被省略。底电极谐振部1042的俯视形状可以是五边形，在本发明的其他实施例中，还可以是四边形或者六边形等，底电极凸起部1041设置在底电极搭接部1040和底电极谐振部1042之间，所述底电极凸起部1041沿着所述底电极谐振部1042的至少一个边设置并连接到所述底电极谐振部1042的相应边上，所述底电极搭接部1040电连接所述底电极凸起部1041背向所述底电极谐振部1042的至少一个边或至少一个角，并从所述底电极凸起部1041的相应边上经覆盖于所述底电极凸起部1041外侧的第一牺牲层103的顶面后延伸到所述第二凹槽102’外围的部分刻蚀保护层101的顶面上，即所述底电极凸起部1041沿着所述底电极谐振部1042的边设置且至少设置在所述底电极搭接部1040和所述底电极谐振部1042对齐的区域中，例如，所述底电极凸起部1041可以环绕所述底电极谐振部1042一周，而构成闭环结构(请参考图2C所示)，也可以是仅沿着所述底电极谐振部1042的一个边设置，还可以是沿着所述底电极谐振部1042的连续两条或连续两条以上的边设置的开环结构(请参考图2A-2B、2D所示)。底电极凸起部1041的形状、线宽以及与有效工作区102A之间的水平距离等均取决于牺牲凸起103’的成型工艺。优选地，如图2D，所述底电极搭接部1040在自身所处的空腔部分上方完全遮盖空腔102，且在所述顶电极搭接部1070的宽度方向，与所述顶电极搭接部1070无重叠，以提高对后续膜层的支撑力，并尽量避免和所述顶电极搭接部1070重叠而引入不必要的寄生参数，例如当第二凹槽102’的俯视形状为矩形时，底电极搭接部1040延伸到该矩形的三条边上。底电极谐振部1042可用作接收或提供诸如射频(RF)信号等的电信号的输入电极或者输出电极。本实施例中，底电极凸起部1041和底电极谐振部1042、底电极搭接部1040具有基本相同的厚度。
请参考图1A、1B和图4E，在步骤S3中，首先，可以使用化学气相沉积、物理气相沉积或原子层沉积等本领域技术人员熟知的任何适合的方法沉积形成压电材料层105；然后，利用光刻工艺在压电材料层105上形成定义有压电薄膜图案的光刻胶层(未图示)，再以光刻胶层为掩膜，刻蚀所述压电材料层105， 以形成压电谐振层1051，之后，将光刻胶层去除。所述压电材料层105的材料可以使用氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO 3)、石英(Quartz)、铌酸钾(KNbO 3)或钽酸锂(LiTaO 3)等具有纤锌矿型结晶结构的压电材料及它们的组合。当压电材料层105包括氮化铝(AlN)时，压电材料层105还可包括稀土金属，例如钪(Sc)、铒(Er)、钇(Y)和镧(La)中的至少一种。此外，当压电材料层105包括氮化铝(AlN)时，压电材料层105还可包括过渡金属，例如锆(Zr)、钛(Ti)、锰(Mn)和铪(Hf)中的至少一种。图案化后剩余的压电材料层105包括相互分离的压电谐振层1051和压电外围部1050，压电谐振层1051位于底电极谐振部1042上，暴露出底电极凸起部1041，且可以完全覆盖或者部分覆盖底电极谐振部1042。压电谐振层1051的形状可以与底电极谐振部1042的形状相同，也可以不同，其俯视形状可以是五边形，也可以是其他多边形，例如四边形、六边形、七边形或者八边形等。压电外围部1050能够和压电谐振层1051之间形成间隙，以暴露出底电极凸起部1041以及所述底电极谐振部1042周围的第一牺牲层103，并进一步通过形成的间隙来限制后续第二牺牲层的形成区域，同时为后续第二牺牲凸起的形成提供相对平坦的工艺表面，压电外围部1050还可以实现后续形成的顶电极外围部和之前形成底电极外围部1043之间的隔离，同时为后续第二牺牲层和顶电极层的形成提供相对平坦的工艺表面。
请参考图1A、1B和图4F，在步骤S4中，首先，可以通过涂覆工艺或者气相沉积工艺等合适的工艺，在压电外围部1050、压电谐振层1051以及压电外围部1050和压电谐振层1051之间的间隙中覆盖第二牺牲层106，且第二牺牲层106能填满压电外围部1050与压电谐振层1051之间的间隙，该第二牺牲层106的材料可以选自非晶碳、光刻胶、介电材料(例如氮化硅、碳氧化硅、多孔材料等)或半导体材料(例如多晶硅、非晶硅、锗)等中的至少一种，第二牺牲层106的材质优选为与第一牺牲层103的材质相同，以能够在后续采用同一种牺牲层去除工艺来一道将第一牺牲层103和第二牺牲层106去除，简化工艺，降低成本；然后，通过CMP工艺对第二牺牲层106进行顶部平坦化，以使得第二牺牲层106仅填充在压电外围部1050与压电谐振层1051之间的间隙中，且压电外围部1050、压电谐振层1051和第二牺牲层106构成平坦的上表面，以能够在后续形成底面平坦的顶电极层。在本发明的其他实施例中，也可以通过回刻蚀工艺去除压电外围部1050与压电谐振层1051上表面上的第二牺牲层106， 使其仅填充在压电外围部1050与压电谐振层1051之间的间隙中。
请参考图1A、图1B和图4F，在步骤S5中，首先，可以根据预定形成的顶电极的材料选择适合的方法在压电外围部1050、压电谐振层1051、第二牺牲层106的表面上覆盖顶电极材料层(未图示)，例如可以通过磁控溅射、蒸镀等物理气相沉积或者化学气相沉积方法形成顶电极材料层，并对顶电极材料层进行顶部平坦化，使得顶电极材料层可以在各个位置厚度均一；然后，利用光刻工艺在顶电极材料层上形成定义有顶电极图案的光刻胶层(未图示)，再以光刻胶层为掩膜，刻蚀所述顶电极材料层，以形成顶部平坦的顶电极层(即图案化的顶电极材料层或剩余的顶电极材料层)107，之后，将光刻胶层去除。顶电极材料层可以使用本领域技术任意熟知的任意合适的导电材料或半导体材料，其中，导电材料可以为具有导电性能的金属材料，例如，Al、Cu、Pt、Au、Mo、W、Ir、Os、Re、Pd、Rh及Ru中的一种或几种，所述半导体材料例如Si、Ge、SiGe、SiC、SiGeC等。本实施例中，顶电极层107包括覆盖在压电谐振层1051上的顶电极谐振部1071以及从顶电极谐振部1071一侧经部分第二牺牲层106的顶面延伸到第二牺牲层106外侧的压电外围部1050上的顶电极搭接部1070以及与顶电极谐振部1071分离的顶电极外围部1072，该顶电极外围部1072与顶电极搭接部1070背向顶电极谐振部1071的一侧连接，以用做该区域待形成的体声波谐振器的一个金属接点，也可以与顶电极搭接部1070分离，以作为相邻的体声波谐振器的顶电极搭接部的一部分，在本发明的其他实施例中，顶电极外围部1072可以被省略。顶电极谐振部1071的俯视形状可以与压电谐振层1051的形状相同，也可以不同，其俯视形状例如为五边形，其面积优选为大于压电谐振层1051，以使得压电谐振层1051被顶电极谐振部1071和底电极谐振部1042完全夹在中间，从而有利于器件尺寸的减小以及寄生参数的降低，在本发明的其他实施例中，顶电极谐振部1071的形状还可以是四边形、六边形、七边形或者八边形等多边形。顶电极层107可用作接收或提供诸如射频(RF)信号等的电信号的输入电极或输出电极。例如，当底电极层104用作输入电极时，顶电极层107可用作输出电极，并且当底电极层104用作输出电极时，顶电极层107可用作输入电极，压电谐振层1051将通过顶电极谐振部1071或底电极谐振部1042上输入的电信号转换为体声波。例如，压电谐振层1051通过物理振动将电信号转换为体声波。所述顶电极搭接部1070电连接所述顶电极谐振部1071 远离第一牺牲层103中心的一侧，并从所述顶电极谐振部1071上经部分第二牺牲层106的顶面延伸到凹槽102’外侧的部分刻蚀保护层101的顶面，所述顶电极搭接部1070和所述底电极搭接部1040相互错开(即二者在形成的空腔102区域不重叠)，且所述顶电极搭接部1070和所述底电极搭接部1040分别暴露出凹槽102’的至少一个边(即底电极层和顶电极层均不会对空腔全面覆盖)，由此能够减少空腔周围的膜层对压电谐振层产生的纵向振动的影响，提高性能。在本发明的一实施例中，请参考图2A，在所述凹槽102’的底面上的投影中，所述底电极凸起部1041的投影可以暴露所述顶电极搭接部1070的投影。所述顶电极搭接部1070和所述底电极搭接部1040在所述凹槽102’的底面上的投影正好相接(如图2C所示)或相互分离(如图1A、2A、2B所示)，所述顶电极搭接部1070可以仅延伸到所述凹槽102’的一条边外围的部分衬底的上方，以有利于减少寄生参数且有利于空腔的无效区的面积减小。
请参考图1A、1B和图4G，在步骤S6中，可以通过光刻结合刻蚀工艺或者激光切割工艺，在压电外围部1050面向凹槽102’的边缘或者体声波谐振器的器件区外围进行打孔，以形成能够暴露出部分第一牺牲层103或部分第二牺牲层106的至少一个释放孔(未图示)；然后，向所述释放孔中通入气体和/或药液，以去除所述第二牺牲层106和所述第一牺牲层103，进而重新清空凹槽以形成空腔102，该空腔102包括底电极凸起部1041限制的凹槽102’的空间及顶电极搭接部1070下方的原先被第二牺牲层106占据的空间。其中，悬空于空腔102上方且依次层叠的底电极谐振部1042、压电谐振层1051和顶电极谐振部1071组成独立体声薄膜，且底电极谐振部1042、压电谐振层1051、顶电极谐振部1071和空腔102沿着竖直方向彼此重叠的部分为有效区域，定义为有效工作区102A，在该有效工作区102A中，当诸如射频信号的电能施加到底电极谐振部1042和顶电极谐振部1071时，会因在压电谐振层1051中产生的压电现象而在压电谐振层1051的厚度方向(即纵向)上产生振动和谐振，空腔102的其他区域为无效区102B，在该无效区102B中，即使当电能施加到顶电极层107和底电极层104时也不因压电现象而谐振的区域。悬空于有效工作区102A上方且依次层叠的底电极谐振部1042、压电谐振层1051和顶电极谐振部1071组成的独立体声薄膜能够输出与压电谐振层1051的压电现象的振动对应的谐振频率的射频信号。具体地，当电能施加到顶电极谐振部1071和底电极谐振部1042时，通过 在压电谐振层1051中产生的压电现象而产生体声波。在这种情况下，从产生的体声波除了期望的纵波还有寄生的横波，该横波会在底电极凸起部1041处被阻挡，将横波限制在有效工作区102A中，防止其传播到空腔外围的膜层中，由此改善因横波向空腔外围的膜层中传播而引起的声波损耗，从而使谐振器的品质因子得到提高，最终能够提高器件性能。此外，由于本实施例中第二牺牲层106的顶面和压电谐振层1051的顶面齐平，因此可以使得形成的所述顶电极层107的底面齐平、顶面也齐平，此时所述顶电极层107在全局范围内均平坦延伸。
需要说明的是，步骤S6可以在待形成的空腔102上方的所有膜层均制作完成后再执行，由此，可以继续利用第一牺牲层103和第二牺牲层106来保护空腔102所在的空间以及其上形成的底电极层104至顶电极层107堆叠的膜层结构，以避免在空腔102形成之后继续进行后续工艺时造成的空腔坍塌风险。此外，在步骤S6中形成的释放孔，可以先一直保留，使得释放孔能够利用后续的两衬底键合等的封装工艺来密封，进而使得空腔102封闭。
需要注意的是，上述各实施例的体声波谐振器的制造方法的步骤S1中，通过刻蚀衬底形成凹槽102’和填充凹槽102’的工艺来形成第一牺牲层于部分衬底上，以使得步骤S6中形成的空腔102为整个底部凹陷在所述衬底中的凹槽结构，但本发明的技术方案并不仅仅限定于此，在本发明的其他实施例的步骤S1中，还可以通过膜层沉积结合光刻和刻蚀工艺来形成整体上凸设于衬底上的第一牺牲层103，以使得步骤S6形成中的空腔102为整体上凸设在所述衬底表面上的腔体结构，具体地，请参考图2D和图5，在步骤S1中，在提供的衬底中不再形成用于制作空腔102的凹槽102’，而是先在基底100表面的刻蚀保护层101上覆盖第一牺牲层103；然后通过光刻结合刻蚀的工艺，将第一牺牲层103图案化，仅保留覆盖在区域102上的第一牺牲层103，进而第一牺牲层103于部分衬底上，该第一牺牲层103可以是上窄下宽的结构，第一牺牲层103的厚度决定了后续形成的空腔102的深度之后，在第一牺牲层103和衬底上覆盖用于制作牺牲凸起103’的牺牲材料层，然后通过光刻结合刻蚀的工艺，形成牺牲凸起103’于部分第一牺牲层103上。在该实施例中，后续步骤与图4A至图4H所示的实施例的体声波谐振器的制造方法中的相应部分完全相同，在此不再赘述，只是形成的底电极外围部1043、底电极搭接部1040、压电外围部1050、顶电极外围部1072、顶电极搭接部1070的相应侧壁需要适应凸立的第一牺牲层103而变形， 纵向截面均变为“Z”形结构。此时，顶电极层107位于空腔102上方的部分是平坦延伸的，即顶电极搭接部1070位于空腔上方(不包括对应第一牺牲层103侧壁的部分)的顶面和顶电极谐振部1071的顶面齐平，顶电极搭接部1070位于空腔上方(不包括对应第一牺牲层103侧壁的部分)的底面和顶电极谐振部1071的底面齐平。
本发明的体声波谐振器优选地采用本发明的体声波谐振器的制作方法，以将底电极搭接部、底电极凸起部与底电极谐振部一道制作，将顶电极搭接部与顶电极谐振部一道制作，进而简化工艺，降低制作成本。
显然，本领域的技术人员可以对发明进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (22)

  1. 一种体声波谐振器，其特征在于，包括：
    衬底；
    底电极层，设置在所述衬底上，且所述底电极层和所述衬底之间形成有空腔，所述底电极层具有底电极凸起部，所述底电极凸起部位于所述空腔的区域中且向着远离所述空腔的底面的方向凸起；
    压电谐振层，形成在所述空腔上方的所述底电极层上，所述底电极凸起部围绕所述压电谐振层的周边方向延伸并被所述压电谐振层暴露出来；
    顶电极层，形成在所述压电谐振层上，且所述顶电极层位于所述空腔上方的部分是平坦延伸的。
  2. 如权利要求1所述的体声波谐振器，其特征在于，所述底电极层还包括底电极谐振部和底电极搭接部，所述底电极谐振部与所述压电谐振层重叠，所述底电极凸起部围绕所述底电极谐振部的周边方向延伸并连接所述底电极谐振部，所述底电极搭接部一端连接所述底电极凸起部，另一端搭接到所述空腔外围的衬底上；所述顶电极层包括相互连接的顶电极谐振部以及顶电极搭接部，所述顶电极谐振部顶面平坦且与所述压电谐振层重叠，所述顶电极搭接部从所述顶电极谐振部的一侧平坦地延伸到所述空腔外围的部分衬底的上方，所述底电极搭接部和所述顶电极搭接部相互错开。
  3. 如权利要求2所述的体声波谐振器，其特征在于，所述底电极谐振部和所述顶电极谐振部均为多边形。
  4. 如权利要求3所述的体声波谐振器，其特征在于，所述底电极凸起部沿着所述底电极谐振部的边设置且至少设置在所述底电极搭接部和所述底电极谐振部对齐的区域中。
  5. 如权利要求4所述的体声波谐振器，其特征在于，所述底电极凸起部在所述空腔上方至少与所述顶电极搭接部相互错开，或者，所述底电极凸起部环绕所述底电极谐振部一周。
  6. 如权利要求2所述的体声波谐振器，其特征在于，所述底电极凸起部、所述底电极搭接部和所述底电极谐振部采用同一膜层形成，所述顶电极搭接部和所述顶电极谐振部采用同一膜层形成。
  7. 如权利要求4所述的体声波谐振器，其特征在于，所述底电极搭接部在自身所处的空腔部分上方完全遮盖空腔，且在所述顶电极搭接部的宽度方向，与所述顶电极搭接部无重叠。
  8. 如权利要求1至7中任一项所述的体声波谐振器，其特征在于，所述底电极凸起部与所述压电谐振层之间的水平距离为制造所述底电极凸起部的工艺所允许的最小距离。
  9. 如权利要求1至7中任一项所述的体声波谐振器，其特征在于，所述底电极凸起部的侧壁相对所述压电谐振层的底面倾斜。
  10. 如权利要求9所述的体声波谐振器，其特征在于，所述底电极凸起部的侧壁与所述压电谐振层的底面之间的夹角小于等于45度。
  11. 如权利要求1至7或10中任一项所述的体声波谐振器，其特征在于，所述底电极凸起部的线宽为制造所述底电极凸起部的工艺所允许的最小线宽。
  12. 如权利要求1至7或10中任一项所述的体声波谐振器，其特征在于，所述空腔为整个底部凹陷在所述衬底中的凹槽结构或者为整体上凸设在所述衬底表面上的腔体结构。
  13. 一种滤波器，其特征在于，包括至少一个如权利要求1至12中任一项所述的体声波谐振器。
  14. 一种射频通信系统，其特征在于，包括至少一个如权利要求13所述的滤波器。
  15. 一种体声波谐振器的制造方法，其特征在于，包括：
    提供衬底，形成具有牺牲凸起的第一牺牲层于部分所述衬底上；
    形成底电极层于所述第一牺牲层上，所述底电极层覆盖在所述牺牲凸起的表面上的部分形成底电极凸起部；
    形成压电谐振层于所述底电极层上，所述底电极凸起部围绕所述压电谐振层的周边方向延伸且被所述压电谐振层暴露出来；
    形成第二牺牲层于所述压电谐振层周围暴露出的区域中，所述第二牺牲层和所述压电谐振层的顶面齐平；
    形成顶电极层于所述压电谐振层及压电谐振层周围的部分第二牺牲层上；
    去除所述第二牺牲层和具有所述牺牲凸起的所述第一牺牲层，所述第二牺牲层和所述第一牺牲层的位置形成空腔，所述底电极凸起部位于所述压电谐振 层外围的空腔区域中，且所述顶电极层位于所述空腔上方的部分是平坦延伸的。
  16. 如权利要求15所述的体声波谐振器的制造方法，其特征在于，形成具有牺牲凸起的第一牺牲层于部分衬底上的步骤包括：刻蚀所述衬底，以形成凹槽于所述衬底中；形成第一牺牲层填充于所述凹槽中；在所述第一牺牲层和所述衬底上覆盖牺牲材料层，图案化所述牺牲材料层，以形成牺牲凸起凸设于部分所述第一牺牲层上；或者
    形成具有牺牲凸起的第一牺牲层于部分衬底上的步骤包括：覆盖第一牺牲层于所述衬底上；图案化所述第一牺牲层，以形成第一牺牲层凸设于部分所述衬底上；在所述第一牺牲层和所述衬底上覆盖牺牲材料层，图案化所述牺牲材料层，以形成牺牲凸起凸设于部分所述第一牺牲层上。
  17. 如权利要求15所述的体声波谐振器的制造方法，其特征在于，去除所述第二牺牲层和所述具有牺牲凸起的第一牺牲层的步骤包括：
    在形成顶电极层之后，形成至少一个释放孔，所述释放孔至少暴露出部分所述第二牺牲层、部分所述牺牲凸起或所述牺牲凸起以外的部分所述第一牺牲层；
    向所述释放孔中通入气体和/或药液，以去除所述第二牺牲层和所述具有所述牺牲凸起的第一牺牲层。
  18. 如权利要求15至17中任一项所述的体声波谐振器的制造方法，其特征在于，形成所述底电极层的步骤包括：沉积底电极材料层覆盖于具有所述牺牲凸起的所述第一牺牲层上；图案化所述底电极材料层，以形成依次连接的底电极搭接部、所述底电极凸起部和底电极谐振部，所述底电极谐振部与所述压电谐振层重叠，所述底电极搭接部背向所述底电极凸起部的一端搭接到所述空腔外围的衬底上。
  19. 如权利要求18所述的体声波谐振器的制造方法，其特征在于，形成所述顶电极层步骤包括：沉积顶电极材料层覆盖于所述第二牺牲层以及压电谐振层上；对所述顶电极材料层进行顶面平坦化；图案化所述顶电极材料层，以形成依次连接的顶电极搭接部和顶电极谐振部，所述顶电极谐振部与所述压电谐振层重叠，所述顶电极搭接部背向所述顶电极谐振部的一侧平坦地延伸到所述空腔外围的部分衬底上方，且所述顶电极搭接部和所述底电极搭接部相互错开。
  20. 如权利要求19所述的体声波谐振器的制造方法，其特征在于，所述底 电极谐振部和所述顶电极谐振部均为多边形，所述底电极凸起部沿着所述底电极谐振部的边设置且至少设置在所述底电极搭接部和所述底电极谐振部对齐的区域中，所述顶电极搭接部沿着所述顶电极谐振部的边设置。
  21. 如权利要求15至17和19至20中任一项所述的体声波谐振器的制造方法，其特征在于，所述底电极凸起部与所述压电谐振层之间的水平距离为制造所述底电极凸起部的工艺所允许的最小距离。
  22. 如权利要求15至17和19至20中任一项所述的体声波谐振器的制造方法，其特征在于，所述底电极凸起部的线宽为制造所述底电极凸起部的工艺所允许的最小线宽。
PCT/CN2019/105096 2019-04-04 2019-09-10 体声波谐振器及其制造方法和滤波器、射频通信系统 WO2020199511A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2021525816A JP7194476B2 (ja) 2019-04-04 2019-09-10 バルク音響波共振器及びその製造方法並びにフィルタ、無線周波数通信システム
US17/449,836 US20220029603A1 (en) 2019-04-04 2021-10-04 Bulk acoustic wave resonator, filter and radio frequency communication system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910272252.2A CN111786644B (zh) 2019-04-04 2019-04-04 体声波谐振器及其制造方法和滤波器、射频通信系统
CN201910272252.2 2019-04-04

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/105089 Continuation WO2020199506A1 (zh) 2019-04-04 2019-09-10 体声波谐振器及其制造方法和滤波器、射频通信系统

Related Child Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/105093 Continuation WO2020199509A1 (zh) 2019-04-04 2019-09-10 体声波谐振器及其制造方法和滤波器、射频通信系统

Publications (1)

Publication Number Publication Date
WO2020199511A1 true WO2020199511A1 (zh) 2020-10-08

Family

ID=72664765

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/105096 WO2020199511A1 (zh) 2019-04-04 2019-09-10 体声波谐振器及其制造方法和滤波器、射频通信系统

Country Status (3)

Country Link
JP (1) JP7194476B2 (zh)
CN (1) CN111786644B (zh)
WO (1) WO2020199511A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117200741A (zh) * 2023-09-14 2023-12-08 武汉敏声新技术有限公司 一种体声波谐振组件及其制备方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230157179A1 (en) * 2021-02-22 2023-05-18 Boe Technology Group Co., Ltd. Piezoelectric element, piezoelectric vibrator and manufacturing method and driving method thereof, and electronic device
WO2022226911A1 (zh) * 2021-04-29 2022-11-03 天津大学 压电mems硅谐振器及其形成方法、电子设备
CN113381722A (zh) * 2021-06-20 2021-09-10 深圳市封神微电子有限公司 一种抑制能量泄露和寄生的高q值薄膜体声波谐振器
US20220321094A1 (en) * 2022-06-21 2022-10-06 Newsonic Technologies Bulk acoustic wave filter having release hole and fabricating method of the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1450719A (zh) * 2002-04-11 2003-10-22 三星电机株式会社 薄膜体声波谐振器及其制造方法
CN1652459A (zh) * 2004-02-05 2005-08-10 精工爱普生株式会社 压电振动片、压电振子及压电振荡器
JP2009290371A (ja) * 2008-05-27 2009-12-10 Panasonic Electric Works Co Ltd Ｂａｗ共振装置
CN105680813A (zh) * 2016-02-25 2016-06-15 锐迪科微电子（上海）有限公司 一种薄膜体声波谐振器及其制造方法
CN108123695A (zh) * 2016-11-30 2018-06-05 三星电机株式会社 体声波谐振器

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4024741B2 (ja) * 2003-10-20 2007-12-19 富士通メディアデバイス株式会社 圧電薄膜共振子及びフィルタ
US8981876B2 (en) * 2004-11-15 2015-03-17 Avago Technologies General Ip (Singapore) Pte. Ltd. Piezoelectric resonator structures and electrical filters having frame elements
JP2006211296A (ja) * 2005-01-28 2006-08-10 Sony Corp マイクロマシンの製造方法およびマイクロマシン
JP4870541B2 (ja) * 2006-12-15 2012-02-08 太陽誘電株式会社 圧電薄膜共振器およびフィルタ
JP5080858B2 (ja) * 2007-05-17 2012-11-21 太陽誘電株式会社 圧電薄膜共振器およびフィルタ
JP2009124640A (ja) * 2007-11-19 2009-06-04 Hitachi Media Electoronics Co Ltd 薄膜圧電バルク波共振器およびその製造方法、並びに薄膜圧電バルク波共振器を用いた薄膜圧電バルク波共振器フィルタ
US10352904B2 (en) * 2015-10-26 2019-07-16 Qorvo Us, Inc. Acoustic resonator devices and methods providing patterned functionalization areas
KR102642898B1 (ko) * 2016-02-18 2024-03-04 삼성전기주식회사 음향 공진기 모듈 및 그 제조 방법
CN106100601A (zh) * 2016-05-31 2016-11-09 中电科技德清华莹电子有限公司 一种采用超薄压电单晶体制作的薄膜体声波谐振器
CN109546985A (zh) * 2018-11-02 2019-03-29 天津大学 体声波谐振器及其制造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1450719A (zh) * 2002-04-11 2003-10-22 三星电机株式会社 薄膜体声波谐振器及其制造方法
CN1652459A (zh) * 2004-02-05 2005-08-10 精工爱普生株式会社 压电振动片、压电振子及压电振荡器
JP2009290371A (ja) * 2008-05-27 2009-12-10 Panasonic Electric Works Co Ltd Ｂａｗ共振装置
CN105680813A (zh) * 2016-02-25 2016-06-15 锐迪科微电子（上海）有限公司 一种薄膜体声波谐振器及其制造方法
CN108123695A (zh) * 2016-11-30 2018-06-05 三星电机株式会社 体声波谐振器

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117200741A (zh) * 2023-09-14 2023-12-08 武汉敏声新技术有限公司 一种体声波谐振组件及其制备方法
CN117200741B (zh) * 2023-09-14 2024-04-16 武汉敏声新技术有限公司 一种体声波谐振组件及其制备方法

Also Published As

Publication number Publication date
CN111786644A (zh) 2020-10-16
CN111786644B (zh) 2023-01-06
JP7194476B2 (ja) 2022-12-22
JP2022507318A (ja) 2022-01-18

Similar Documents

Publication Publication Date Title
WO2020199507A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
US11005448B2 (en) Film bulk acoustic wave resonators and fabrication methods thereof
WO2020199511A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
US11942917B2 (en) Film bulk acoustic resonator and fabrication method thereof
CN112039465B (zh) 一种薄膜体声波谐振器及其制造方法
JP7130841B2 (ja) 薄膜バルク音響波共振器及びその製造方法
WO2020199510A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
WO2020199508A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
WO2021232763A1 (zh) 一种薄膜体声波谐振器及其制造方法
WO2021012917A1 (zh) 薄膜体声波谐振器及其制造方法和滤波器、射频通信系统
WO2022100469A1 (zh) 一种薄膜体声波谐振器及其制造方法和滤波器
CN112787614A (zh) 一种薄膜拉姆波谐振器、滤波器及其制造方法
WO2020199509A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
WO2020199504A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
WO2020199506A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统
US20220029603A1 (en) Bulk acoustic wave resonator, filter and radio frequency communication system
CN112311353A (zh) 一种牢固安置型体声波谐振器及其制造方法
JP7251837B2 (ja) 薄膜バルク音響波共振器およびその製造方法
WO2020199505A1 (zh) 体声波谐振器及其制造方法和滤波器、射频通信系统

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: 19922369

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021525816

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19922369

Country of ref document: EP

Kind code of ref document: A1