CN116488608A - Film bulk acoustic resonator, manufacturing method thereof and filter - Google Patents
Film bulk acoustic resonator, manufacturing method thereof and filter Download PDFInfo
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- CN116488608A CN116488608A CN202310598366.2A CN202310598366A CN116488608A CN 116488608 A CN116488608 A CN 116488608A CN 202310598366 A CN202310598366 A CN 202310598366A CN 116488608 A CN116488608 A CN 116488608A
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- 238000003475 lamination Methods 0.000 claims abstract description 35
- 239000010409 thin film Substances 0.000 claims description 51
- 238000000034 method Methods 0.000 claims description 30
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/131—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials consisting of a multilayered structure
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/132—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials characterized by a particular shape
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/173—Air-gaps
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/028—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks for obtaining desired values of other parameters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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
The invention relates to the technical field of semiconductors, and provides a film bulk acoustic resonator, a manufacturing method thereof and a filter, wherein the film bulk acoustic resonator comprises: a substrate; a piezoelectric stack structure; the piezoelectric lamination structure comprises a bottom electrode, a piezoelectric material layer and a top electrode which are sequentially arranged on the substrate from bottom to top, wherein the bottom electrode, the piezoelectric material layer and the top electrode form an effective resonance area of the piezoelectric lamination structure in a region which is mutually overlapped in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure; the effective resonance area of the piezoelectric lamination structure protrudes away from the substrate in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure to form an air cavity; the effective resonance region of the piezoelectric stack structure is formed with a convex structure and/or a concave structure at the top. The Q value of the resonator can be improved while the problem of low mechanical strength of the conventional acoustic wave resonator is solved, so that the performance of the device is improved.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a film bulk acoustic resonator, a manufacturing method thereof and a filter.
Background
With the rapid development of 5G communication technology, the performance of the thin film bulk acoustic resonator is directly determined by the filtering effect of the filter as a basic device of many filters.
Film bulk acoustic resonators (Film Bulk Acoustic Resonator, FBAR), which are typically fabricated on industrially produced semiconductor (e.g., silicon/silicon carbide/gallium nitride, etc.) substrate substrates, are mainly composed of an acoustic wave reflecting structure/a metal bottom electrode/a piezoelectric film/a metal top electrode/and lead-out electrical connection lines to the outside. A periodic alternating electric field is applied to two ends of the piezoelectric film, the piezoelectric film deforms to generate sound waves, standing wave resonance is generated at a specific frequency when the sound waves propagate in the longitudinal direction of the piezoelectric film, and the thickness of the piezoelectric film is half of the wavelength of the sound waves in the piezoelectric film. Thus, the piezoelectric film exhibits the same electrical resonance characteristics as those of a quartz crystal resonator, and can be used for manufacturing electromagnetic wave resonators and filters.
The structure capable of improving the quality factor Q value of the thin film bulk acoustic resonator is provided in the prior art, and the purposes of changing boundary acoustic impedance conditions and inhibiting the existence of parasitic transverse waves are achieved by changing part of the structure of the thin film bulk acoustic resonator, so that the loss of expected longitudinal mechanical wave energy is reduced, and further the quality factor Q value of a device and the product yield are improved. However, the conventional thin film bulk acoustic resonator based on the silicon back side etching structure has low mechanical strength, poor structural stability, and a Q value thereof is hardly improved, resulting in poor steepness of the resonator and high insertion loss.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a film bulk acoustic resonator, a manufacturing method thereof and a filter, and aims to improve the mechanical strength and the Q value of the film bulk acoustic resonator.
In a first aspect of the present invention, a thin film bulk acoustic resonator is provided, including:
a substrate;
a piezoelectric stack structure;
the piezoelectric lamination structure comprises a bottom electrode, a piezoelectric material layer and a top electrode which are sequentially arranged on the substrate from bottom to top, wherein the bottom electrode, the piezoelectric material layer and the top electrode form an effective resonance area of the piezoelectric lamination structure in a region which is mutually overlapped in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure;
the effective resonance area of the piezoelectric lamination structure is far away from the substrate in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure to form an air cavity;
wherein, the effective resonance area of the piezoelectric lamination structure is provided with a convex structure and/or a concave structure at the top.
Optionally, the bottom electrode includes a bottom electrode resonance part located in the effective resonance area, a bottom electrode lead-out part extending out of the effective resonance area, and a bottom electrode connection part connecting the bottom electrode resonance part and the bottom electrode lead-out part; the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending out of the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
Optionally, the projections of the bottom electrode lead-out part and the top electrode lead-out part on the surface of the piezoelectric material layer are staggered.
Optionally, the bump structure has an upper surface and a lower surface parallel to a contact surface of the substrate and the piezoelectric stack structure; the area of the upper surface of the protruding structure is smaller than the area of the lower surface of the protruding structure, and the first projection of the upper surface of the protruding structure on the top electrode surface is covered by the second projection of the lower surface of the protruding structure on the top electrode surface.
Optionally, the protruding structure includes protruding structure layer that a plurality of stromatolite set up, and adjacent protruding structure layer adopts different materials preparation to obtain.
Optionally, the concave structure has a concave bottom surface and a concave opening surface parallel to a contact surface of the substrate and the piezoelectric stack structure; the area of the bottom surface of the concave is different from the area of the opening surface of the concave, and the third projection of the bottom surface of the concave on the surface of the top electrode is covered by the fourth projection of the opening surface of the concave on the surface of the top electrode, or the fourth projection of the opening surface of the concave on the surface of the top electrode is covered by the third projection of the bottom surface of the concave on the surface of the top electrode.
Optionally, the concave structure is filled with at least one dielectric material.
In a second aspect of the invention, a filter is provided comprising a thin film bulk acoustic resonator as described above.
In a third aspect of the present invention, a method for manufacturing a thin film bulk acoustic resonator is provided, including:
providing a substrate;
forming a sacrificial bump on the substrate, the sacrificial bump being located below an effective resonant area;
sequentially forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric laminated structure on the substrate and the sacrificial protrusion;
forming a convex structure and/or a concave structure above an effective resonance region of the piezoelectric stack structure;
and removing the sacrificial protrusion to form an air cavity.
Optionally, the method for sequentially forming the bottom electrode, the piezoelectric material layer and the top electrode of the piezoelectric stack structure includes:
forming a bottom electrode on the substrate and the sacrificial protrusion, wherein the bottom electrode comprises a bottom electrode resonance part positioned in an effective resonance area, a bottom electrode leading-out part extending to the outside of the effective resonance area and a bottom electrode connecting part connecting the bottom electrode resonance part and the bottom electrode leading-out part;
forming a piezoelectric material layer on the substrate and the bottom electrode, wherein the piezoelectric material layer comprises a piezoelectric material resonance part positioned in an effective resonance area, a first piezoelectric material leading-out part extending out of the effective resonance area, a second piezoelectric material leading-out part extending out of the effective resonance area, a first piezoelectric material connecting part connecting the piezoelectric material resonance part and the first piezoelectric material leading-out part, and a second piezoelectric material connecting part connecting the piezoelectric material resonance part and the second piezoelectric material leading-out part;
And forming a top electrode on the piezoelectric material layer, wherein the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
Optionally, the projections of the bottom electrode lead-out part and the top electrode lead-out part on the surface of the piezoelectric material layer are staggered.
Optionally, the protruding structure includes protruding structure layer that a plurality of stromatolite set up, and adjacent protruding structure layer adopts different materials preparation to obtain.
Optionally, the method for forming the bump structure includes:
and sequentially growing materials corresponding to different convex structure layers on the upper surface of the top electrode, and patterning the convex structure layers after each layer of material is grown.
Optionally, the method for forming the concave structure includes:
a recess structure of a specific shape is etched on the top electrode.
Optionally, after forming the piezoelectric material layer on the substrate and the bottom electrode, the method further includes:
forming a bottom layer of a top electrode on the piezoelectric material layer, wherein the bottom layer of the top electrode comprises a top electrode resonance part positioned in an effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part;
The method for forming the concave structure comprises the following steps:
and photoetching and stripping the bottom layer of the top electrode to form a concave structure with a specific shape.
Optionally, the method for manufacturing the film bulk acoustic resonator further includes:
and filling at least one dielectric material in the concave structure.
The beneficial effects of the invention are as follows:
the thin film bulk acoustic resonator is characterized in that an air cavity is arranged between a substrate and a piezoelectric lamination structure, so that an interface between metal and air is formed between the substrate and an oscillation area of the resonator, and the problem of low mechanical strength of a conventional acoustic resonator is solved while sound waves are limited in a piezoelectric oscillation stack; by adopting the convex and/or concave structures, the Q value of the resonator can be effectively improved by adopting the convex structures, so that the steepness of the resonator is improved and the insertion loss is reduced; the concave structure has the effect of improving the Q value of the resonator, and can effectively inhibit stray modes, so that the response of the resonator is smoother, and the problems of low mechanical strength and difficult improvement of the Q value of the traditional film bulk acoustic resonator based on the silicon back etching structure are solved.
Drawings
Fig. 1 is a schematic cross-sectional structure of a thin film bulk acoustic resonator having a bump structure in embodiment 1 of the present invention;
FIG. 2 is a graph showing the frequency response of an original resonator and a resonator having a bump structure in example 1 of the present invention;
FIG. 3 is a schematic view of the first shape of the bump structure (right trapezoid) in embodiment 1 of the present invention;
FIG. 4 is a schematic view of a second shape of the convex structure (isosceles trapezoid) in embodiment 1 of the present invention;
FIG. 5 is a schematic view of a third shape of the convex structure (generally trapezoidal) in embodiment 1 of the present invention;
FIG. 6 is a first structural form of the double-layered bump structure in embodiment 1 of the present invention;
FIG. 7 is a second structural form of the double-layered bump structure in embodiment 1 of the present invention;
fig. 8 is a schematic cross-sectional structure of a thin film bulk acoustic resonator having a concave structure in embodiment 2 of the present invention;
FIG. 9 is a graph showing the frequency response of an original resonator and a resonator having a concave structure in example 2 of the present invention;
fig. 10 is a first structural form (isosceles trapezoid) of the concave structure in embodiment 2 of the present invention;
FIG. 11 is an isosceles trapezoid with a center rotated 180 DEG, which is a first structural form of the concave structure in embodiment 2 of the present invention;
fig. 12 is a schematic cross-sectional structure of a thin film bulk acoustic resonator having a convex structure and a concave structure in embodiment 3 of the present invention;
FIG. 13 is a graph showing the frequency response of an original resonator and a resonator having a convex structure and a concave structure in example 3 of the present invention;
fig. 14 is a flow chart showing a method of manufacturing a thin film bulk acoustic resonator having a bump structure in embodiment 5 of the present invention;
fig. 15 is a flow chart showing a method of manufacturing a thin film bulk acoustic resonator having a concave structure in embodiment 6 of the present invention;
fig. 16 is a flow chart showing a method of manufacturing a thin film bulk acoustic resonator having a convex structure and a concave structure in example 7 of the present invention.
Reference numerals:
1-a substrate; 2-a seed layer; 3-a bottom electrode; 4-a layer of piezoelectric material; 5-top electrode; 6-internal connection metal; 7-an air cavity; 8-a bump structure; 9-concave structure.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Film bulk acoustic resonators (Film Bulk Acoustic Resonator, FBAR), which are typically fabricated on industrially produced semiconductor (e.g., silicon/silicon carbide/gallium nitride, etc.) substrate substrates, are mainly composed of an acoustic wave reflecting structure/a metal bottom electrode/a piezoelectric film/a metal top electrode/and lead-out electrical connection lines to the outside. A periodic alternating electric field is applied to two ends of the piezoelectric film, the piezoelectric film deforms to generate sound waves, standing wave resonance is generated at a specific frequency when the sound waves propagate in the longitudinal direction of the piezoelectric film, and the thickness of the piezoelectric film is half of the wavelength of the sound waves in the piezoelectric film. Thus, the piezoelectric film exhibits the same electrical resonance characteristics as those of a quartz crystal resonator, and can be used for manufacturing electromagnetic wave resonators and filters.
The structure capable of improving the quality factor Q value of the thin film bulk acoustic resonator is provided in the prior art, and the purposes of changing boundary acoustic impedance conditions and inhibiting the existence of parasitic transverse waves are achieved by changing part of the structure of the thin film bulk acoustic resonator, so that the loss of expected longitudinal mechanical wave energy is reduced, and further the quality factor Q value of a device and the product yield are improved. However, the conventional thin film bulk acoustic resonator based on the silicon back side etching structure has low mechanical strength, poor structural stability, and a Q value thereof is hardly improved, resulting in poor steepness of the resonator and high insertion loss.
Therefore, the air cavity is arranged between the substrate and the piezoelectric laminated structure, so that an interface between metal and air is formed between the substrate and the vibration area of the resonator, and the problem of low mechanical strength of the conventional acoustic wave resonator is solved while the acoustic wave is limited in the piezoelectric vibration stack; by adopting the convex and/or concave structures, the Q value of the resonator can be effectively improved by adopting the convex structures, so that the steepness of the resonator is improved and the insertion loss is reduced; the concave structure has the effect of improving the Q value of the resonator, and can effectively inhibit stray modes, so that the response of the resonator is smoother, and the problems of low mechanical strength and difficult improvement of the Q value of the traditional film bulk acoustic resonator based on the silicon back etching structure are solved.
Example 1:
referring to fig. 1, fig. 1 is a schematic cross-sectional structure of a film bulk acoustic resonator according to embodiment 1 of the present invention, the film bulk acoustic resonator comprising: a substrate 1 and a piezoelectric stack structure.
The piezoelectric lamination structure comprises a bottom electrode 3, a piezoelectric material layer 4 and a top electrode 5 which are sequentially arranged on the substrate 1 from bottom to top, wherein the area where the bottom electrode 3, the piezoelectric material layer 4 and the top electrode 5 are mutually overlapped in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure forms an effective resonance area of the piezoelectric lamination structure;
Wherein, the effective resonance area of the piezoelectric lamination structure is protruded away from the substrate 1 in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure to form an air cavity 7;
wherein the effective resonance area of the piezoelectric stack structure is formed with a bump structure 8 at the top.
It should be noted that the material of the substrate 1 may be any suitable substrate known to those skilled in the art, for example, at least one of the following materials may be mentioned: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III/V compound semiconductors, and also include multilayer structures composed of these semiconductors, or the like, or are silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon-on-insulator (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), or may be double-sided polished silicon wafers (Double Side Polished Wafers, DSP), or may be ceramic substrates such as alumina, quartz, or glass substrates, or the like.
The piezoelectric material layer 4 may be aluminum nitride (AlN), scandium-doped aluminum nitride (AlScN), zinc oxide (ZnO), lead zirconate titanate (PZT), or the like. The bottom electrode 3 and the top electrode 5 are metal electrodes, and generally commonly used materials such as platinum (Pt), aluminum (Al), ruthenium (Ru), molybdenum (Mo), and gold (Au). The bottom electrode 3 may be directly grounded or electrically floating.
In one embodiment, an electrode outlet for placing an internal connection metal 6 is formed on the piezoelectric material layer 4, and the internal connection metal 6 is used for connecting and leading out the bottom electrode 3 under the piezoelectric material layer 4, so as to control the potential of the bottom electrode 3, and further, form a potential difference between the bottom electrode 3 and the top electrode 5.
In a preferred embodiment, the bottom electrode 3 comprises a bottom electrode 3 resonance part located in the effective resonance area, a bottom electrode 3 extraction part extending to the outside of the effective resonance area, and a bottom electrode 3 connection part connecting the bottom electrode 3 resonance part and the bottom electrode 3 extraction part; the top electrode 5 comprises a top electrode 5 resonance part positioned in the effective resonance area, a top electrode 5 extraction part extending out of the effective resonance area and a top electrode 5 connection part connecting the top electrode 5 resonance part and the top electrode 5 extraction part.
In the region between the resonance portion of the bottom electrode 3 and the resonance portion of the top electrode 5, when there is a potential difference between the bottom electrode 3 and the top electrode 5, an electric field therebetween can effectively excite acoustic resonance in the piezoelectric material layer 4, thereby generating a frequency response as shown by the solid line in fig. 2.
Meanwhile, the effective resonance area of the piezoelectric laminated structure is far away from the substrate 1 in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric laminated structure to form an air cavity 7, and an interface between metal and air is formed between the substrate 1 and the oscillation area of the resonator by means of the arrangement of the air cavity 7, so that sound waves can be effectively limited in the piezoelectric oscillation stack, and the mechanical strength of the resonator can be maintained.
In a preferred embodiment, the projections of the leading-out portions of the bottom electrode 3 and the leading-out portions of the top electrode 5 on the surface of the piezoelectric material layer 4 are staggered with each other.
In this embodiment, in the ineffective resonance region other than the effective resonance region, the top electrode 5 and the bottom electrode 3 have no overlapping region in the direction perpendicular to the contact surface between the substrate 1 and the piezoelectric stack structure, so that the problem of high-frequency coupling caused by potential floating can be avoided, parasitic capacitance is prevented from being formed, and the Q value of the resonator is advantageously improved.
In one embodiment, the substrate 1 is further plated with a seed layer 2, which can promote the surface uniformity of the deposit on the substrate 1 and improve the performance of the device.
In order to optimize the resonator performance, in the present embodiment, the effective resonance area of the piezoelectric stack structure is formed with a bump structure 8 on top, and the bump structure 8 can effectively increase the resonance frequency f of the resonator p The Q value at this point is shown in dashed lines in fig. 2.
It should be noted that, the bump structure 8 provided in this embodiment may use a metal material and a dielectric material, wherein the metal material may be tungsten (W), platinum (Pt), aluminum (Al), ruthenium (Ru), molybdenum (Mo), gold (Au), and the dielectric material may be silicon dioxide (SiO) 2 ) Gallium nitride (GaN), silicon nitride (Si) 3 N 4 ) Aluminum nitride (AlN), and the like.
In a preferred embodiment, the bump structure 8 has an upper surface and a lower surface parallel to the contact surface of the substrate 1 with the piezoelectric stack structure, the area of the upper surface of the bump structure 8 is smaller than the area of the lower surface of the bump structure 8, and a first projection of the upper surface of the bump structure 8 on the surface of the top electrode 5 is covered by a second projection of the lower surface of the bump structure 8 on the surface of the top electrode 5.
Specifically, as shown in fig. 3, the bump structure 8 may be a right trapezoid structure whose size is defined by a thickness T 1 Length of bottom edge L 1 And base angle theta 1 Defined, and bottom edge length L 1 And thickness T 1 The value of (2) is determined by the resonator operating frequency. Wherein the thickness T 1 Typically between 50 nanometers and 1 micrometer, bottom edge length L 1 Typically between 0.5 microns and 10 microns, with a base angle theta 1 Typically between 10 deg. and 90 deg..
In addition to the right trapezoid structure shown in fig. 3, the convex structure 8 according to the present embodiment may also be an isosceles trapezoid structure shown in fig. 4 (i.e. base angle θ 2 Equal to theta 3 ) And the generally trapezoidal configuration shown in fig. 5 (i.e., base angle theta 4 Not equal to theta 5 And theta is theta 4 、θ 5 Less than 90 °). In the actual design process, the shape of the bump structure 8 can be reasonably selected according to specific requirements and the process technology.
In a preferred embodiment, the bump structure 8 comprises a plurality of bump structure layers arranged in a stacked manner, and adjacent bump structure layers are made of different materials.
Specifically, in order to further improve the Q value of the resonator, the bump structure 8 provided in this embodiment may also be a multi-layer material structure, so as to introduce more discontinuities, thereby better restricting the sound wave to the piezoelectric oscillation stack and improving the sound wave resonance effect.
The multi-layer material can be selected and matched at will from the materials of the convex structures 8 according to actual requirements. FIG. 6 is a silicon dioxide (SiO) 2 ) And molybdenum (Mo) two-layer material illustrate the composition of the multi-layer bump structure 8. The double-layer convex structure 8 can be two as shown in fig. 6Silicon oxide (SiO) 2 ) The molybdenum (Mo) may be the molybdenum (Mo) shown in fig. 7, the silicon dioxide (SiO 2 ) On top. It should be noted that, other schemes with any materials can be selected by those skilled in the art according to the needs, and the embodiments are not described herein again.
The embodiment provides a film bulk acoustic resonator, by adopting an air cavity 7, an interface between metal and air is formed between a silicon substrate 1 and an oscillation area of the resonator, so that the problem of low mechanical strength of a conventional acoustic resonator is solved while acoustic waves are limited in a piezoelectric oscillation stack, and the Q value of the resonator can be effectively improved by arranging a convex structure 8, thereby improving the steepness of the resonator and reducing the insertion loss.
Example 2
Referring to fig. 8, fig. 8 is a schematic cross-sectional structure of a thin film bulk acoustic resonator according to embodiment 2 of the present invention, the thin film bulk acoustic resonator comprising:
a substrate 1;
a piezoelectric stack structure;
the piezoelectric lamination structure comprises a bottom electrode 3, a piezoelectric material layer 4 and a top electrode 5 which are sequentially arranged on the substrate 1 from bottom to top, wherein the area where the bottom electrode 3, the piezoelectric material layer 4 and the top electrode 5 are mutually overlapped in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure forms an effective resonance area of the piezoelectric lamination structure;
wherein, the effective resonance area of the piezoelectric lamination structure is protruded away from the substrate 1 in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure to form an air cavity 7;
wherein the effective resonance region of the piezoelectric stack structure is formed with a recess structure 9 at the top.
In this embodiment, the effective resonance region of the piezoelectric stack structure is formed with a recess structure 9 at the top, as compared with embodiment 1. By introducing the recess 9, the resonator in fig. 9 is at the resonant frequency f s And f p The Q value between the two can be effectively improved, thereby effectively improving the resonator Is not shown, and insertion loss is not shown. Furthermore, the recess structure 9 may also help the resonator suppress spurious modes, thereby making the frequency response of the resonator smoother.
In a preferred embodiment, the recess structure 9 has a recess bottom surface and a recess opening surface parallel to the contact surface of the substrate 1 with the piezoelectric stack structure; the area of the bottom surface of the recess is different from the area of the opening surface of the recess, and the third projection of the bottom surface of the recess on the surface of the top electrode 5 is covered by the fourth projection of the opening surface of the recess on the surface of the top electrode 5, or the fourth projection of the opening surface of the recess on the surface of the top electrode 5 is covered by the third projection of the bottom surface of the recess on the surface of the top electrode 5.
Specifically, as shown in fig. 10, the concave structure 9 may be an isosceles trapezoid concave structure 9, whose specific dimension is defined by a height T 2 Length of bottom edge L 2 And the complement angle theta of the base angle 6 Is defined. Wherein the height T of the concave structure 9 2 The supplementary angle theta of the base angle is generally between 5% and 90% of the thickness of the electrode 6 Typically between 10 deg. and 90 deg.. As shown in fig. 11, the concave structure 9 may also be a pattern structure obtained by rotating the center of the isosceles trapezoid concave structure 9 shown in fig. 10 by 180 °. In the actual design processing, the specific shape, size, etc. of the concave structure 9 can be reasonably selected according to the actual requirements and the process level.
In a preferred embodiment, the recess 9 is filled with at least one dielectric material.
In this embodiment, the performance of the resonator can be further optimized by filling the recess structure 9 with dielectric materials, which can be selected from silicon dioxide (SiO 2 ) Gallium nitride (GaN), silicon nitride (Si) 3 N 4 ) Aluminum nitride (AlN), and the like.
The embodiment provides a film bulk acoustic resonator, by adopting an air cavity 7, an interface between metal and air is formed between a silicon substrate 1 and an oscillation area of the resonator, so that the problem of low mechanical strength of a conventional acoustic resonator is solved while acoustic waves are limited in a piezoelectric oscillation stack, and by arranging a concave structure 9, the Q value of the resonator can be effectively improved, and a stray mode can be effectively restrained, so that the response of the resonator is smoother.
Example 3
Referring to fig. 12, fig. 12 is a schematic cross-sectional structure of a thin film bulk acoustic resonator according to embodiment 3 of the present invention, the thin film bulk acoustic resonator comprising:
a substrate 1;
a piezoelectric stack structure;
the piezoelectric lamination structure comprises a bottom electrode 3, a piezoelectric material layer 4 and a top electrode 5 which are sequentially arranged on the substrate 1 from bottom to top, wherein the area where the bottom electrode 3, the piezoelectric material layer 4 and the top electrode 5 are mutually overlapped in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure forms an effective resonance area of the piezoelectric lamination structure;
Wherein, the effective resonance area of the piezoelectric lamination structure is protruded away from the substrate 1 in the direction perpendicular to the contact surface of the substrate 1 and the piezoelectric lamination structure to form an air cavity 7;
wherein the effective resonance region of the piezoelectric stack structure is formed with a convex structure 8 and a concave structure 9 at the top.
In this embodiment, the effective resonance region of the piezoelectric stack structure is formed with a convex structure 8 and a concave structure 9 on top, compared with embodiment 1 and embodiment 2. Fig. 13 shows the frequency response of the resonator of fig. 12 with a greatly improved Q-value, thereby improving the steepness and insertion loss of the resonator. In addition, spurious modes of the resonator are also effectively suppressed, thereby making the frequency response of the resonator smoother.
The present embodiment provides a thin film bulk acoustic resonator, which combines the advantages of embodiments 1 and 2, and by adopting the air cavity 7, an interface between metal and air is formed between the silicon substrate 1 and the oscillation area of the resonator, so that the problem of low mechanical strength of the conventional acoustic resonator is solved while the acoustic wave is limited in the piezoelectric oscillation stack, the Q value of the resonator can be effectively improved by arranging the convex structure 8, thereby improving the steepness of the resonator and reducing the insertion loss, and the Q value of the resonator can be effectively improved by arranging the concave structure 9, and the spurious modes can be effectively suppressed, so that the response of the resonator is smoother.
Example 4
A filter according to embodiment 4 of the present invention includes a thin film bulk acoustic resonator as described in any one of embodiments 1 to 3.
In a specific embodiment, when the filter includes the thin film bulk acoustic resonator as described in embodiment 1, the filter has all the advantages of the thin film bulk acoustic resonator described in embodiment 1: the problem of low mechanical strength of the conventional acoustic wave resonator is solved while the acoustic wave is limited in the piezoelectric oscillation stack, and the Q value of the resonator can be effectively improved by arranging the convex structure, so that the steepness of the resonator is improved and the insertion loss is reduced.
In another specific embodiment, when the filter includes the thin film bulk acoustic resonator as in embodiment 2, the filter has all the advantages of the thin film bulk acoustic resonator described in embodiment 2: the problem of low mechanical strength of the conventional acoustic wave resonator is solved while the acoustic wave is limited in the piezoelectric oscillation stack, the Q value of the resonator can be effectively improved by arranging the concave structure, and stray modes can be effectively restrained, so that the response of the resonator is smoother.
In yet another specific embodiment, when the filter includes the thin film bulk acoustic resonator as in embodiment 3, the filter has all the advantages of the thin film bulk acoustic resonator described in embodiment 3: the problem of low mechanical strength of a conventional acoustic wave resonator is solved while the acoustic wave is limited in the piezoelectric oscillation stack, and the Q value of the resonator can be effectively improved by arranging the convex structure, so that the steepness of the resonator is improved, the insertion loss is reduced, the Q value of the resonator can be effectively improved by arranging the concave structure, and the stray mode can be effectively restrained, so that the response of the resonator is smoother.
Example 5
Referring to fig. 14, fig. 14 is a flow chart of a method for manufacturing a thin film bulk acoustic resonator according to embodiment 5 of the present invention, for manufacturing a thin film bulk acoustic resonator according to embodiment 1, the method comprising:
s1: providing a substrate;
s2: forming a sacrificial bump on the substrate, the sacrificial bump being located below an effective resonant area;
s3: sequentially forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric laminated structure on the substrate and the sacrificial protrusion;
s4: forming a convex structure above an effective resonance region of the piezoelectric stack structure;
s5: and removing the sacrificial protrusion to form an air cavity.
In a preferred embodiment, the method for sequentially forming the bottom electrode, the piezoelectric material layer and the top electrode of the piezoelectric stack structure includes:
s31: forming a bottom electrode on the substrate and the sacrificial protrusion, wherein the bottom electrode comprises a bottom electrode resonance part positioned in an effective resonance area, a bottom electrode leading-out part extending to the outside of the effective resonance area and a bottom electrode connecting part connecting the bottom electrode resonance part and the bottom electrode leading-out part;
s32: forming a piezoelectric material layer on the substrate and the bottom electrode, wherein the piezoelectric material layer comprises a piezoelectric material resonance part positioned in an effective resonance area, a first piezoelectric material leading-out part extending out of the effective resonance area, a second piezoelectric material leading-out part extending out of the effective resonance area, a first piezoelectric material connecting part connecting the piezoelectric material resonance part and the first piezoelectric material leading-out part, and a second piezoelectric material connecting part connecting the piezoelectric material resonance part and the second piezoelectric material leading-out part;
S33: and forming a top electrode on the piezoelectric material layer, wherein the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
In this embodiment, after the sacrificial bump is formed on the substrate, the steps of forming the bottom electrode on the substrate and the sacrificial bump, forming the piezoelectric material layer on the substrate and the bottom electrode, and forming the piezoelectric stack structure of the top electrode on the piezoelectric material layer are sequentially performed.
Therefore, the effective resonance area of the piezoelectric laminated structure is formed by utilizing the sacrificial bulge to form a bulge part of the piezoelectric laminated structure along the direction perpendicular to the contact surface of the substrate and the piezoelectric laminated structure and away from the substrate bulge, and an air cavity is formed after the sacrificial bulge is removed. The manufactured film bulk acoustic resonator can improve the mechanical strength of the resonator while limiting the acoustic wave in the piezoelectric oscillation stack.
In a preferred embodiment, the projections of the bottom electrode lead-out portion and the top electrode lead-out portion on the surface of the piezoelectric material layer are staggered with each other.
In this embodiment, in the ineffective resonance region other than the effective resonance region, the top electrode and the bottom electrode have no overlapping region in the direction perpendicular to the contact surface of the substrate and the piezoelectric stack structure, so that the problem of high-frequency coupling caused by potential floating can be avoided, parasitic capacitance is prevented from being formed, and the Q value of the resonator is advantageously improved.
In one embodiment, the step S1: providing a substrate, further comprising:
s11: a seed layer is grown over the substrate.
The seed layer grown on the substrate can promote the surface uniformity of the sediment on the substrate and improve the performance of the device.
In one embodiment, the step S3: forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric stack structure on the substrate and the sacrificial bump in sequence, and then, the method further comprises:
s31: forming an electrode outlet on the piezoelectric material layer;
s32: and growing an internal connection metal at the electrode outlet.
The internal connection metal is used for connecting and leading out the bottom electrode below the piezoelectric material layer, controlling the potential of the bottom electrode, and further forming a potential difference between the bottom electrode and the top electrode.
In a preferred embodiment, the protruding structure comprises a plurality of protruding structure layers arranged in a stacked manner, and adjacent protruding structure layers are prepared from different materials.
On this basis, the step S4: forming a convex structure above an effective resonance region of the piezoelectric stack structure, specifically comprising:
s41: and sequentially growing materials corresponding to different convex structure layers on the upper surface of the top electrode, and patterning the convex structure layers after each layer of material is grown.
It should be noted that, in the processing of the bump structure composed of multiple layers of materials in this embodiment, it is necessary to sequentially grow a first layer of material, perform specific pattern etching, regrow a second layer of material and perform specific pattern etching, so as to obtain a bump structure composed of multiple bump structure layers.
The embodiment provides a manufacturing method of a film bulk acoustic resonator, wherein a sacrificial bulge is formed on a substrate, an air cavity is formed through a piezoelectric lamination structure formed on the substrate and the sacrificial bulge, and an interface between metal and air is formed between a silicon substrate and an oscillation area of the resonator, so that the problem of low mechanical strength of a conventional acoustic resonator is solved while sound waves are limited in a piezoelectric oscillation stack; meanwhile, the bump structure is formed above the effective resonance region of the piezoelectric stack structure, so that the Q value of the resonator can be effectively increased, thereby improving the steepness of the resonator and reducing the insertion loss.
Example 6
Referring to fig. 15, fig. 15 is a flow chart showing a method for manufacturing a thin film bulk acoustic resonator according to embodiment 6 of the present invention, for manufacturing a thin film bulk acoustic resonator according to embodiment 2, the method comprising:
s1: providing a substrate;
s2: forming a sacrificial bump on the substrate, the sacrificial bump being located below an effective resonant area;
s3: sequentially forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric laminated structure on the substrate and the sacrificial protrusion;
s4: forming a concave structure above an effective resonance region of the piezoelectric stack structure;
s5: and removing the sacrificial protrusion to form an air cavity.
In comparison with embodiment 4, in this embodiment, after the bottom electrode, the piezoelectric material layer, and the top electrode of the piezoelectric stack structure are formed, a concave structure is formed over the effective resonance region of the piezoelectric stack structure.
Specifically, there are two possible processes for forming the recess structure.
Firstly, the whole top electrode is grown, and then the concave structure with a specific shape is etched by dry etching (dry etching).
Specifically, the step S4: forming a concave structure above an effective resonance region of the piezoelectric stack structure, specifically comprising:
S41: a recess structure of a specific shape is etched on the top electrode.
Secondly, the process method divides the top electrode into an upper layer and a lower layer for processing, grows a solid metal layer at the bottom, and then utilizes a photoetching 'lift-off' process to process the concave structure on the layer.
Specifically, after forming the piezoelectric material layer on the substrate and the bottom electrode, it further includes: and forming a bottom layer of the top electrode on the piezoelectric material layer, wherein the bottom layer of the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
On this basis, the step S4: forming a concave structure above an effective resonance region of the piezoelectric stack structure, specifically comprising:
s41: and photoetching and stripping the bottom layer of the top electrode to form a concave structure with a specific shape.
It should be noted that, for the isosceles trapezoid recessed structure shown in fig. 10 in embodiment 2, the recessed structure may be formed by any one of the two processes; whereas for the isosceles trapezoid recessed structure shown in fig. 11 in embodiment 2, the recessed structure can be formed only by the second process method.
In a preferred embodiment, the step S4: forming a recess structure over an effective resonant area of the piezoelectric stack structure, after which the method further comprises:
s42: and filling at least one dielectric material in the concave structure.
In this embodiment, the performance of the resonator may be further optimized by filling each dielectric material in the recess structure, and the dielectric material may be silicon dioxide (SiO 2 ) Gallium nitride (GaN), silicon nitride (Si) 3 N 4 ) Aluminum nitride (AIN), and the like.
The embodiment provides a manufacturing method of a film bulk acoustic resonator, wherein a sacrificial bulge is formed on a substrate, an air cavity is formed through a piezoelectric lamination structure formed on the substrate and the sacrificial bulge, and an interface between metal and air is formed between a silicon substrate and an oscillation area of the resonator, so that the problem of low mechanical strength of a conventional acoustic resonator is solved while sound waves are limited in a piezoelectric oscillation stack; meanwhile, a concave structure is formed above an effective resonance area of the piezoelectric laminated structure, so that the Q value of the resonator can be effectively improved, stray modes can be effectively restrained, and the response of the resonator is smoother.
Example 7
Referring to fig. 16, fig. 16 is a flow chart showing a method for manufacturing a thin film bulk acoustic resonator according to embodiment 6 of the present invention, for manufacturing a thin film bulk acoustic resonator according to embodiment 3, the method comprising:
S1: providing a substrate;
s2: forming a sacrificial bump on the substrate, the sacrificial bump being located below an effective resonant area;
s3: sequentially forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric laminated structure on the substrate and the sacrificial protrusion;
s4: forming a convex structure and a concave structure above an effective resonance region of the piezoelectric stack structure;
s5: and removing the sacrificial protrusion to form an air cavity.
In this embodiment, after the bottom electrode, the piezoelectric material layer, and the top electrode of the piezoelectric stack structure are formed, the convex structure and the concave structure are formed over the effective resonance region of the piezoelectric stack structure, as compared with embodiment 4 and embodiment 5.
The embodiment provides a manufacturing method of a film bulk acoustic resonator, which combines the advantages of embodiment 4 and embodiment 5, forms a sacrificial protrusion on a substrate, forms an air cavity through a piezoelectric laminated structure formed on the substrate and the sacrificial protrusion, and forms an interface between metal and air between a silicon substrate and an oscillation area of the resonator, thereby solving the problem of low mechanical strength of a conventional acoustic resonator while limiting acoustic waves in a piezoelectric oscillation stack; meanwhile, a convex structure is formed above an effective resonance area of the piezoelectric laminated structure, so that the Q value of the resonator can be effectively improved, the steepness of the resonator is improved, the insertion loss is reduced, a concave structure is formed above the effective resonance area of the piezoelectric laminated structure, the Q value of the resonator can be effectively improved, and stray modes can be effectively restrained, so that the response of the resonator is smoother.
In describing embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "inner", "outer", "inside", "outside", etc. indicate orientations or positional relationships based on the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Wherein "inside" refers to an interior or enclosed area or space. "peripheral" refers to the area surrounding a particular component or region.
In the description of embodiments of the present invention, the terms "first," "second," "third," "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", "a third" and a fourth "may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In describing embodiments of the present invention, it should be noted that the terms "mounted," "connected," and "assembled" are to be construed broadly, as they may be fixedly connected, detachably connected, or integrally connected, unless otherwise specifically indicated and defined; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In the description of embodiments of the invention, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.
In the description of the embodiments of the present invention, it is to be understood that "-" and "-" denote the same ranges of the two values, and the ranges include the endpoints. For example: "A-B" means a range greater than or equal to A and less than or equal to B. "A-B" means a range of greater than or equal to A and less than or equal to B.
In the description of embodiments of the present invention, the term "and/or" is merely an association relationship describing an association object, meaning that three relationships may exist, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (16)
1. A thin film bulk acoustic resonator, comprising:
a substrate;
a piezoelectric stack structure;
the piezoelectric lamination structure comprises a bottom electrode, a piezoelectric material layer and a top electrode which are sequentially arranged on the substrate from bottom to top, wherein the bottom electrode, the piezoelectric material layer and the top electrode form an effective resonance area of the piezoelectric lamination structure in a region which is mutually overlapped in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure;
the effective resonance area of the piezoelectric lamination structure is far away from the substrate in the direction perpendicular to the contact surface of the substrate and the piezoelectric lamination structure to form an air cavity;
wherein, the effective resonance area of the piezoelectric lamination structure is provided with a convex structure and/or a concave structure at the top.
2. The thin film bulk acoustic resonator of claim 1, wherein the bottom electrode comprises a bottom electrode resonating section located in the effective resonating region, a bottom electrode lead-out section extending outside the effective resonating region, and a bottom electrode connecting section connecting the bottom electrode resonating section and the bottom electrode lead-out section; the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending out of the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
3. The thin film bulk acoustic resonator according to claim 2, wherein projections of the bottom electrode lead-out portion and the top electrode lead-out portion on the surface of the piezoelectric material layer are staggered with each other.
4. The thin film bulk acoustic resonator of claim 1, wherein the bump structure has an upper surface and a lower surface parallel to a contact surface of the substrate with the piezoelectric stack structure; the area of the upper surface of the protruding structure is smaller than the area of the lower surface of the protruding structure, and the first projection of the upper surface of the protruding structure on the top electrode surface is covered by the second projection of the lower surface of the protruding structure on the top electrode surface.
5. The thin film bulk acoustic resonator of claim 1, wherein the bump structure comprises a plurality of bump structure layers arranged in a stack, and adjacent bump structure layers are made of different materials.
6. The thin film bulk acoustic resonator of claim 1, wherein the recess structure has a recess bottom surface and a recess opening surface parallel to a contact surface of the substrate with the piezoelectric stack structure; the area of the bottom surface of the concave is different from the area of the opening surface of the concave, and the third projection of the bottom surface of the concave on the surface of the top electrode is covered by the fourth projection of the opening surface of the concave on the surface of the top electrode, or the fourth projection of the opening surface of the concave on the surface of the top electrode is covered by the third projection of the bottom surface of the concave on the surface of the top electrode.
7. The thin film bulk acoustic resonator of claim 1 wherein the recess structure is filled with at least one dielectric material.
8. A filter comprising a thin film bulk acoustic resonator as claimed in any one of claims 1 to 7.
9. A method of manufacturing a thin film bulk acoustic resonator, comprising:
providing a substrate;
forming a sacrificial bump on the substrate, the sacrificial bump being located below an effective resonant area;
sequentially forming a bottom electrode, a piezoelectric material layer and a top electrode of a piezoelectric laminated structure on the substrate and the sacrificial protrusion;
forming a convex structure and/or a concave structure above an effective resonance region of the piezoelectric stack structure;
and removing the sacrificial protrusion to form an air cavity.
10. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, wherein the method of sequentially forming the bottom electrode, the piezoelectric material layer, and the top electrode of the piezoelectric stack structure comprises:
forming a bottom electrode on the substrate and the sacrificial protrusion, wherein the bottom electrode comprises a bottom electrode resonance part positioned in an effective resonance area, a bottom electrode leading-out part extending to the outside of the effective resonance area and a bottom electrode connecting part connecting the bottom electrode resonance part and the bottom electrode leading-out part;
Forming a piezoelectric material layer on the substrate and the bottom electrode, wherein the piezoelectric material layer comprises a piezoelectric material resonance part positioned in an effective resonance area, a first piezoelectric material leading-out part extending out of the effective resonance area, a second piezoelectric material leading-out part extending out of the effective resonance area, a first piezoelectric material connecting part connecting the piezoelectric material resonance part and the first piezoelectric material leading-out part, and a second piezoelectric material connecting part connecting the piezoelectric material resonance part and the second piezoelectric material leading-out part;
and forming a top electrode on the piezoelectric material layer, wherein the top electrode comprises a top electrode resonance part positioned in the effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part.
11. The method of manufacturing a thin film bulk acoustic resonator according to claim 10, wherein projections of the bottom electrode lead-out portion and the top electrode lead-out portion on the surface of the piezoelectric material layer are offset from each other.
12. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, wherein the bump structure comprises a plurality of bump structure layers arranged in a stacked manner, and adjacent bump structure layers are made of different materials.
13. The method of manufacturing a thin film bulk acoustic resonator according to claim 12, characterized in that the method of forming a bump structure comprises:
and sequentially growing materials corresponding to different convex structure layers on the upper surface of the top electrode, and patterning the convex structure layers after each layer of material is grown.
14. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, characterized in that the method of forming a recess structure comprises:
a recess structure of a specific shape is etched on the top electrode.
15. The method of manufacturing a thin film bulk acoustic resonator according to claim 10, further comprising, after forming a piezoelectric material layer on the substrate and the bottom electrode:
forming a bottom layer of a top electrode on the piezoelectric material layer, wherein the bottom layer of the top electrode comprises a top electrode resonance part positioned in an effective resonance area, a top electrode leading-out part extending to the effective resonance area and a top electrode connecting part connecting the top electrode resonance part and the top electrode leading-out part;
the method for forming the concave structure comprises the following steps:
and photoetching and stripping the bottom layer of the top electrode to form a concave structure with a specific shape.
16. The method of manufacturing a thin film bulk acoustic resonator according to claim 9, further comprising:
And filling at least one dielectric material in the concave structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117375568A (en) * | 2023-12-07 | 2024-01-09 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117375568A (en) * | 2023-12-07 | 2024-01-09 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
| CN117375568B (en) * | 2023-12-07 | 2024-03-12 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method for forming bulk acoustic wave resonator device |
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