CN115242215B - Bulk acoustic wave resonator device and method of forming the same - Google Patents
Bulk acoustic wave resonator device and method of forming the same Download PDFInfo
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Images
Classifications
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- H—ELECTRICITY
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- 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
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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
- H03H3/04—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 frequency or temperature coefficient
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- 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
- H03H9/02102—Means for compensation or elimination of undesirable effects of temperature influence
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- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
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- 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
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- 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
- H03H3/04—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 frequency or temperature coefficient
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- H—ELECTRICITY
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- 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
- H03H3/04—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 frequency or temperature coefficient
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Abstract
A bulk acoustic wave resonator and a forming method thereof belong to the technical field of semiconductor manufacturing, wherein the bulk acoustic wave resonator comprises: the method comprises the following steps: a substrate; an intermediate layer comprising opposing first and second sides, the substrate being located on the first side, the intermediate layer comprising a cavity, an opening of the cavity being located on the second side; an electrode structure located within the cavity; a piezoelectric layer on the second side and on the electrode structure, the piezoelectric layer covering at least the cavity. Because the electrode structure is located in the cavity, consequently the piezoelectric layer can provide comparatively flat surface for the frequency modulation layer of follow-up formation, reduces the lattice defect of frequency modulation layer film promotes the film quality, and then makes the frequency modulation layer is more nimble and accurate to the frequency control of device.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to a bulk acoustic wave resonance device and a forming method thereof.
Background
A Radio Frequency (RF) front-end chip of a wireless communication device includes a power amplifier, an antenna switch, a Radio Frequency filter, a multiplexer including a duplexer, a low noise amplifier, and the like. The rf filter includes a Surface Acoustic Wave (SAW) filter, a Bulk Acoustic Wave (BAW) filter, a Micro-Electro-Mechanical System (MEMS) filter, an Integrated Passive Devices (IPD) filter, and the like.
The surface acoustic wave resonator and the bulk acoustic wave resonator have high quality factor values (Q values), and radio frequency filters with low insertion loss and high out-of-band rejection, namely the surface acoustic wave filter and the bulk acoustic wave filter, manufactured by the surface acoustic wave resonator and the bulk acoustic wave resonator are mainstream radio frequency filters used by wireless communication equipment such as mobile phones and base stations at present. Where the Q value is the quality factor value of the resonator, defined as the center frequency divided by the 3dB bandwidth of the resonator. The frequency of use of the surface acoustic wave filter is generally 0.4GHz to 2.7GHz, and the frequency of use of the bulk acoustic wave filter is generally 0.7GHz to 7GHz.
The bulk acoustic wave resonator has better performance than the surface acoustic wave resonator, but the manufacturing cost of the bulk acoustic wave resonator is higher than that of the SAW resonator due to the complicated process steps. However, as wireless communication technology gradually evolves, more and more frequency bands are used, and meanwhile, with the application of frequency band overlapping use technology such as carrier aggregation, mutual interference between wireless frequency bands becomes more and more serious. The high-performance bulk acoustic wave technology can solve the problem of mutual interference between frequency bands. With the advent of the 5G era, higher communication frequency bands are introduced into wireless mobile networks, and currently, only the bulk acoustic wave technology can solve the filtering problem of high frequency bands.
However, there are still many problems with the bulk acoustic wave resonator devices formed in the prior art.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a bulk acoustic wave resonance device and a forming method thereof, so that the frequency control of a frequency modulation layer on a device is more flexible and accurate.
In order to solve the above problems, the present invention provides a bulk acoustic wave resonator device, comprising: a substrate; an intermediate layer comprising opposing first and second sides, the substrate being located on the first side, the intermediate layer comprising a cavity, an opening of the cavity being located on the second side; an electrode structure located within the cavity; a piezoelectric layer on the second side and on the electrode structure, the piezoelectric layer covering at least the cavity.
Optionally, the method further includes: the frequency modulation layer is located the second side and is located the piezoelectric layer top, the projection of electrode structure is in on the base the frequency modulation layer is in the projection range on the base, the intermediate level with the frequency modulation layer is located respectively the both sides of piezoelectric layer, the electrode structure with the frequency modulation layer is located respectively the both sides of piezoelectric layer.
Optionally, the frequency modulation layer includes a groove, and a projection of the electrode structure on the substrate is located within a projection range of the groove on the substrate.
Optionally, the frequency modulation region of the frequency modulation layer includes a plurality of grooves, and a projection of the electrode structure on the substrate is located within a projection range of the frequency modulation region on the substrate.
Optionally, a plurality of the grooves are uniformly distributed in the frequency modulation region.
Optionally, the method further includes: and the temperature compensation layer is positioned on the second side and on the piezoelectric layer, and the piezoelectric layer and the frequency modulation layer are respectively positioned on two sides of the temperature compensation layer.
Optionally, the method further includes: and the temperature compensation layer is positioned in the cavity and at least covers the electrode structure, and the piezoelectric layer is positioned on the temperature compensation layer.
Optionally, the electrode structure includes: the first bus and the second bus are arranged in parallel along a first direction, the first bus is connected with a plurality of first electrode strips which are arranged in parallel along a second direction, the second bus is connected with a plurality of second electrode strips which are arranged in parallel along the second direction, the first direction is vertical to the second direction, and the first electrode strips and the second electrode strips are arranged in a staggered mode.
Optionally, the widths of the first electrode strips and the second electrode strips are equal; the first electrode strips and the second electrode strips have a first width dimension, the central axes of the first electrode strips and the second electrode strips adjacent to each other have a first central dimension, and the ratio of the first central dimension to the first width dimension ranges from: 1.2 to 20.
Optionally, the material of the substrate comprises: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers.
Optionally, the material of the intermediate layer includes: polymer, insulating dielectric, or polysilicon.
Optionally, the material of the electrode structure includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
Optionally, the material of the frequency modulation layer comprises metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
Correspondingly, the technical scheme of the invention also provides a method for forming the bulk acoustic wave resonance device, which comprises the following steps: providing a sacrificial substrate; forming a piezoelectric layer on the sacrificial substrate; forming an electrode structure on the piezoelectric layer; forming a sacrificial layer on the piezoelectric layer, the sacrificial layer covering at least the electrode structure; forming an intermediate layer on the piezoelectric layer, the intermediate layer covering at least the sacrificial layer, the intermediate layer including opposing first and second sides, the piezoelectric layer and the sacrificial substrate being located on the second side; providing a substrate; joining the substrate and the intermediate layer, the substrate being located on the first side; removing the sacrificial substrate after bonding the substrate and the intermediate layer; after removing the sacrificial substrate, removing the sacrificial layer, embedding a cavity in the intermediate layer, wherein an opening of the cavity is located at the second side, and the electrode structure is located in the cavity.
Optionally, after removing the sacrificial substrate and before removing the sacrificial layer, the method further includes: and forming a frequency modulation layer positioned on the second side, wherein the projection of the electrode structure on the substrate is positioned in the projection range of the frequency modulation layer on the substrate, the middle layer and the frequency modulation layer are respectively positioned on two sides of the piezoelectric layer, and the electrode structure and the frequency modulation layer are respectively positioned on two sides of the piezoelectric layer.
Optionally, the frequency modulation layer includes a groove, and a projection of the electrode structure on the substrate is located within a projection range of the groove on the substrate.
Optionally, the frequency modulation region of the frequency modulation layer includes a plurality of grooves, and a projection of the electrode structure on the substrate is located within a projection range of the frequency modulation region on the substrate.
Optionally, a plurality of the grooves are uniformly distributed in the frequency modulation region.
Optionally, before forming the frequency modulation layer, the method further includes: and forming a temperature compensation layer, wherein the temperature compensation layer is positioned on the second side and on the piezoelectric layer, and the piezoelectric layer and the frequency modulation layer are respectively positioned on two sides of the temperature compensation layer.
Optionally, after the forming the electrode structure, the method further includes: forming a temperature compensation layer on the piezoelectric layer and covering at least the electrode structure before forming the sacrificial layer; the sacrificial layer covers the temperature compensation layer; and after removing the sacrificial layer, the temperature compensation layer is located in the cavity.
Optionally, the electrode structure includes: the first bus and the second bus are arranged in parallel along a first direction, the first bus is connected with a plurality of first electrode strips which are arranged in parallel along a second direction, the second bus is connected with a plurality of second electrode strips which are arranged in parallel along the second direction, the first direction is vertical to the second direction, and the first electrode strips and the second electrode strips are arranged in a staggered mode.
Optionally, the widths of the first electrode strips and the second electrode strips are equal; the first electrode strips and the second electrode strips have a first width dimension, the central axes of the first electrode strips and the second electrode strips adjacent to each other have a first central dimension, and the ratio of the first central dimension to the first width dimension ranges from: 1.2 to 20.
Compared with the prior art, the technical scheme of the invention has the following advantages:
the bulk acoustic wave resonator device comprises an electrode structure, wherein the electrode structure is positioned in a cavity. Because the electrode structure is located in the cavity, the piezoelectric layer can provide a relatively flat surface for a subsequently formed frequency modulation layer, so that the lattice defect of the frequency modulation layer film is reduced, the film quality is improved, and the frequency control of the frequency modulation layer on a device is more flexible and accurate. In addition, because the electrode structure is positioned in the cavity, the electrode structure can be effectively prevented from being oxidized or corroded in use of the device.
Further, the frequency modulation layer comprises a groove, and the projection of the electrode structure on the substrate is located within the projection range of the groove on the substrate. By increasing or reducing the depth of the groove, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer can control the frequency of the device more flexibly and accurately.
Further, the frequency modulation region of the frequency modulation layer comprises a plurality of grooves, and the projection of the electrode structure on the substrate is located within the projection range of the frequency modulation region on the substrate. By increasing or decreasing the depth of the plurality of grooves, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer can control the frequency of the device more flexibly and accurately.
In the method for forming the bulk acoustic wave resonator device according to the technical scheme of the present invention, the sacrificial layer is removed, a cavity is formed in the intermediate layer, an opening of the cavity is located at the second side, and the electrode structure is located in the cavity. Because the electrode structure is located in the cavity, the piezoelectric layer can provide a relatively flat surface for a subsequently formed frequency modulation layer, so that the lattice defect of the frequency modulation layer film is reduced, the film quality is improved, and the frequency control of the frequency modulation layer on a device is more flexible and accurate. In addition, because the electrode structure is positioned in the cavity, the electrode structure can be effectively prevented from being oxidized or corroded in use of the device.
Further, the frequency modulation layer comprises a groove, and a projection of the electrode structure on the substrate is located within a projection range of the groove on the substrate. By increasing or decreasing the depth of the plurality of grooves, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer can control the frequency of the device more flexibly and accurately.
Further, the frequency-modulated region of the frequency-modulated layer comprises a plurality of grooves, and the projection of the electrode structure on the substrate is located within the projection range of the frequency-modulated region on the substrate. By increasing or reducing the depth of the groove, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer can control the frequency of the device more flexibly and accurately.
Drawings
Fig. 1 is a schematic structural view of a bulk acoustic wave resonator device;
fig. 2 to 10 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to an embodiment of the present invention;
fig. 11 to 20 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to another embodiment of the present invention;
fig. 21 to 31 are schematic structural diagrams of steps of a bulk acoustic wave resonator device and a method for forming the same according to still another embodiment of the present invention;
fig. 32 to 42 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to still another embodiment of the present invention;
fig. 43 to 53 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to another embodiment of the present invention;
fig. 54 to 65 are schematic structural diagrams of steps of a bulk acoustic wave resonator device and a method for forming the same according to still another embodiment of the present invention;
fig. 66 to 77 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to still another embodiment of the present invention;
fig. 78 to 88 are schematic structural views of steps of a bulk acoustic wave resonator device and a method for forming the same according to still another embodiment of the present invention;
fig. 89 to 100 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to still another embodiment of the present invention;
fig. 101 to 112 are schematic structural diagrams of steps of a bulk acoustic wave resonator and a method for forming the same according to still another embodiment of the present invention.
Detailed Description
As described in the background, the bulk acoustic wave resonator devices formed in the prior art still have problems. The following detailed description will be made in conjunction with the accompanying drawings.
Fig. 1 is a schematic structural view of a bulk acoustic wave resonator device.
Referring to fig. 1, a bulk acoustic wave resonator device includes: a support substrate 100, wherein the support substrate 100 comprises a cavity 101, and the cavity 101 is exposed on the surface of the support substrate 100; a piezoelectric layer 102 located on said support substrate 100 and covering at least said cavity 101; an electrode structure 103 is located on the piezoelectric layer 102.
In this embodiment, a longitudinally propagating shear wave is generated by the excitation of the interdigitated electrodes in the electrode structure 103 to create a resonance in the piezoelectric layer 102.
However, since the electrode structure 103 is formed on the piezoelectric layer 102, when a frequency modulation layer (not shown) needs to be formed on the piezoelectric layer 102, due to the uneven structure of the electrode structure 103, a relatively flat surface cannot be provided for the formation of the frequency modulation layer, and thus lattice defects of the frequency modulation layer film increase, which affects the quality of the frequency modulation layer film, and there is a disadvantage in precise control of the device frequency.
On the basis, the invention provides a bulk acoustic wave resonance device and a forming method thereof. Because the electrode structure is located in the cavity, consequently the piezoelectric layer can provide comparatively flat surface for the frequency modulation layer of follow-up formation, reduces the lattice defect of frequency modulation layer film promotes the film quality, and then makes the frequency modulation layer is more nimble and accurate to the frequency control of device. In addition, because the electrode structure is positioned in the cavity, the electrode structure can be effectively prevented from being oxidized or corroded when the device is used.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Fig. 2 to 10 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to an embodiment of the present invention.
Referring to fig. 2, a sacrificial substrate 203 is provided.
The material of the sacrificial substrate 203 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 203.
Referring to fig. 3, a piezoelectric layer 204 is formed on the sacrificial substrate 203.
The material of the piezoelectric layer 204 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 204.
Referring to fig. 4 and 5, fig. 5 isbase:Sub>A schematic cross-sectional view taken along linebase:Sub>A-base:Sub>A of fig. 4, and an electrode structure 205 is formed on the piezoelectric layer 204.
In this embodiment, the electrode structure 205 includes: the electrode structure comprises a first bus 2051 and a second bus 2052 which are arranged in parallel along a first direction X, wherein the first bus 2051 is connected with a plurality of first electrode strips 2053 which are arranged in parallel along a second direction Y, the second bus 2052 is connected with a plurality of second electrode strips 2054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 2053 and the second electrode strips 2054 are arranged in a staggered manner.
In this embodiment, the first electrode strips 2053 and the second electrode strips 2054 have the same width; the first electrode strip 2053 and the second electrode strip 2054 have a first width dimension d1, the adjacent central axis of the first electrode strip 2053 and the adjacent central axis of the second electrode strip 2054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode strip 2053 and the second electrode strip 2054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 205 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 205 is one or more layers. In this embodiment, the electrode structure 205 is two layers, and the material of the electrode structure 205 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 6, fig. 6 and fig. 5, the view directions are the same, a sacrificial layer 206 is formed on the piezoelectric layer 204, and the sacrificial layer 206 at least covers the electrode structure 205.
The material of the sacrificial layer 206 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the sacrificial layer 206 is polyimide.
Referring to fig. 7, an intermediate layer 201 is formed on the piezoelectric layer 204, the intermediate layer 201 at least covers the sacrificial layer 206, the intermediate layer 201 includes a first side 201a and a second side 201b opposite to each other, and the piezoelectric layer 204 and the sacrificial substrate 203 are located on the second side 201b.
The material of the intermediate layer 201 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 201 is silicon dioxide.
Referring to fig. 8, a substrate 200 is provided.
The materials of the substrate 200 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 200.
Referring to fig. 9, the substrate 200 and the intermediate layer 201 are bonded, the substrate 200 is located on the first side 201a; after bonding the substrate 200 and the intermediate layer 201, the sacrificial substrate 203 is removed.
The process of removing the sacrificial substrate 203 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 203 is a physical polishing process.
In this embodiment, a bonding process is used to join the substrate 200 and the intermediate layer 201; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 10, after removing the sacrificial substrate 203, the sacrificial layer 206 is removed, a cavity 202 is formed in the middle layer 201, an opening of the cavity 202 is located on the second side 201b, and the electrode structure 205 is located in the cavity 202.
In this embodiment, since the electrode structure 205 is located in the cavity 202, the piezoelectric layer 204 can provide a relatively flat surface for a subsequently formed frequency modulation layer, so as to reduce lattice defects of the frequency modulation layer film, improve the film quality, and further enable the frequency modulation layer to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 205 is located in the cavity 202, the electrode structure 205 can be effectively prevented from being oxidized or corroded when the device is in use.
In this embodiment, the process of removing the sacrificial layer 206 is a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 10, which includes: a substrate 200; an intermediate layer 201, said intermediate layer 201 comprising opposing first and second sides 201a, 201b, said substrate 200 being located on said first side 201a, said intermediate layer 201 comprising a cavity 202, an opening of said cavity 202 being located on said second side 201b; an electrode structure 205 located within the cavity 202; a piezoelectric layer 204 on said second side 201b and on said electrode structure 205, said piezoelectric layer 204 at least covering said cavity 205.
In this embodiment, since the electrode structure 205 is located in the cavity 202, the piezoelectric layer 204 can provide a relatively flat surface for a subsequently formed frequency modulation layer, so as to reduce lattice defects of the frequency modulation layer film, improve the film quality, and further enable the frequency modulation layer to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 205 is located in the cavity 202, the electrode structure 205 can be effectively prevented from being oxidized or corroded when the device is in use.
The material of the substrate 200 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 200.
The material of the intermediate layer 201 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 201 is silicon dioxide.
The material of the piezoelectric layer 204 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 204.
In this embodiment, the electrode structure 205 includes: the electrode structure comprises a first bus 2051 and a second bus 2052 which are arranged in parallel along a first direction X, wherein the first bus 2051 is connected with a plurality of first electrode strips 2053 which are arranged in parallel along a second direction Y, the second bus 2052 is connected with a plurality of second electrode strips 2054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 2053 and the second electrode strips 2054 are arranged in a staggered manner.
In this embodiment, the first electrode strips 2053 and the second electrode strips 2054 have equal widths; the first electrode strip 2053 and the second electrode strip 2054 have a first width dimension d1, the adjacent central axis of the first electrode strip 2053 and the adjacent central axis of the second electrode strip 2054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode strip 2053 and the second electrode strip 2054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 205 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 205 is one or more layers. In this embodiment, the electrode structure 205 is two layers, and the material of the electrode structure 205 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Fig. 11 to 20 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to another embodiment of the present invention.
Referring to fig. 11, a sacrificial substrate 303 is provided.
The material of the sacrificial substrate 303 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 303.
Referring to fig. 12, a piezoelectric layer 304 is formed on the sacrificial substrate 303.
The material of the piezoelectric layer 304 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 304.
Referring to fig. 13 and 14, fig. 14 is a schematic cross-sectional view taken along line B-B of fig. 13, wherein an electrode structure 305 is formed on the piezoelectric layer 304.
In this embodiment, the electrode structure 305 includes: first bus 3051 and second bus 3052 of arranging along first direction X parallel, first bus 3051 is connected a plurality of first electrode strip 3053 of arranging along second direction Y parallel, second bus 3052 is connected a plurality of edges second electrode strip 3054 of arranging along second direction Y parallel, first direction X with second direction Y is perpendicular, first electrode strip 3053 with second electrode strip 3054 is crisscross to be placed.
In this embodiment, the first electrode 3053 and the second electrode 3054 are equal in width; the first electrode 3053 and the second electrode 3054 have a first width dimension d1, the central axis of the first electrode 3053 and the central axis of the second electrode 3054 adjacent to each other have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 is in the range of: 1.2 to 20.
In the present embodiment, the thickness of the first electrode 3053 and the second electrode 3054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 305 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 305 is one or more layers. In this embodiment, the electrode structure 305 has two layers, and the material of the electrode structure 305 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 15, fig. 15 and fig. 14 are shown in the same view direction, a sacrificial layer 307 is formed on the piezoelectric layer 304, and the sacrificial layer 307 at least covers the electrode structure 305.
The material of the sacrificial layer 307 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, polyimide is used as the material of the sacrificial layer 307.
Referring to fig. 16, an intermediate layer 301 is formed on the piezoelectric layer 304, the intermediate layer 301 at least covers the sacrificial layer 307, the intermediate layer 301 includes a first side 301a and a second side 301b opposite to each other, and the piezoelectric layer 304 and the sacrificial substrate 303 are located on the second side 301b.
The material of the intermediate layer 301 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 301 is silicon dioxide.
Referring to fig. 17, a substrate 300 is provided.
The materials of the substrate 300 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 300.
Referring to fig. 18, the substrate 300 and the intermediate layer 301 are bonded, the substrate 300 is located at the first side 301a; after bonding the substrate 300 and the intermediate layer 301, the sacrificial substrate 303 is removed.
The process of removing the sacrificial substrate 303 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 303 adopts a physical grinding process.
In this embodiment, a bonding process is used to bond the substrate 300 and the intermediate layer 301; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 19, a frequency modulation layer 306 is formed, located on the second side 301b and located on the piezoelectric layer 304, a projection of the electrode structure 305 on the substrate 300 is located in a projection range of the frequency modulation layer 306 on the substrate 300, the middle layer 301 and the frequency modulation layer 306 are respectively located on two sides of the piezoelectric layer 304, and the electrode structure 305 and the frequency modulation layer 306 are respectively located on two sides of the piezoelectric layer 304.
The material of the frequency modulation layer 306 comprises metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 306 is silicon nitride.
Referring to fig. 20, after the frequency modulation layer 306 is formed, the sacrificial layer 307 is removed, a cavity 302 is formed in the middle layer 301, an opening of the cavity 302 is located on the second side 301b, and the electrode structure 305 is located in the cavity 302.
In this embodiment, since the electrode structure 305 is located in the cavity 302, the piezoelectric layer 304 can provide a relatively flat surface for the formed frequency modulation layer 306, so as to reduce lattice defects of the thin film of the frequency modulation layer 306, and improve the quality of the thin film, thereby enabling the frequency modulation layer 306 to control the frequency of the device more flexibly and accurately. In addition, since the electrode structure 305 is located in the cavity 302, the electrode structure 305 can be effectively prevented from being oxidized or corroded during the use of the device.
In this embodiment, the process of removing the sacrificial layer 306 adopts a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 20, which includes: a substrate 300; an intermediate layer 301, said intermediate layer 301 comprising opposing first and second sides 301a and 301b, said substrate 300 being located on said first side 301a, said intermediate layer 301 comprising a cavity 302, an opening of said cavity 302 being located on said second side 301b; an electrode structure 305 located within the cavity 302; a piezoelectric layer 304 on said second side 301b and on said electrode structure 305, said piezoelectric layer 304 covering at least said cavity 302; the fm layer 306 is located on the second side 301b and located on the piezoelectric layer 304, the projection of the electrode structure 305 on the substrate 300 is located within the projection range of the fm layer 306 on the substrate 300, the middle layer 301 and the fm layer 306 are located on two sides of the piezoelectric layer 304, respectively, and the electrode structure 305 and the fm layer 306 are located on two sides of the piezoelectric layer 304, respectively.
In this embodiment, since the electrode structure 305 is located in the cavity 302, the piezoelectric layer 304 can provide a relatively flat surface for the formed frequency modulation layer 306, so as to reduce lattice defects of the thin film of the frequency modulation layer 306, and improve the quality of the thin film, thereby enabling the frequency modulation layer 306 to control the frequency of the device more flexibly and accurately. In addition, since the electrode structure 305 is located in the cavity 302, the electrode structure 305 can be effectively prevented from being oxidized or corroded during the use of the device.
The material of the substrate 300 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 300 is made of silicon.
The material of the intermediate layer 301 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 301 is silicon dioxide.
The material of the piezoelectric layer 304 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 304.
In this embodiment, the electrode structure 305 includes: the electrode assembly comprises a first bus 3051 and a second bus 3052 which are arranged in parallel along a first direction X, the first bus 3051 is connected with a plurality of first electrode bars 3053 which are arranged in parallel along a second direction Y, the second bus 3052 is connected with a plurality of second electrode bars 3054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode bars 3053 and the second electrode bars 3054 are arranged in a staggered mode.
In this embodiment, the first electrode 3053 and the second electrode 3054 are equal in width; the first electrode 3053 and the second electrode 3054 have a first width dimension d1, the adjacent central axis of the first electrode 3053 and the central axis of the second electrode 3054 have a first center dimension d2, the ratio of the first center dimension d2 to the first width dimension d1 being in the range of: 1.2 to 20.
In this embodiment, the thickness of the first electrode bar 3053 and the second electrode bar 3054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 305 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 305 is one or more layers. In this embodiment, the electrode structure 305 has two layers, and the material of the electrode structure 305 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the frequency modulation layer 306 comprises metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 306 is silicon nitride.
Fig. 21 to 31 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator device according to still another embodiment of the present invention.
Referring to fig. 21, a sacrificial substrate 403 is provided.
The material of the sacrificial substrate 403 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 403.
Referring to fig. 22, a piezoelectric layer 404 is formed on the sacrificial substrate 403.
The material of the piezoelectric layer 404 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 404.
Referring to fig. 23 and 24, fig. 24 is a schematic cross-sectional view taken along line C-C in fig. 23, and an electrode structure 405 is formed on the piezoelectric layer 404.
In this embodiment, the electrode structure 405 includes: first bus 4051 and second bus 4052 of arranging along first direction X parallel, a plurality of first electrode strips 4053 of arranging along second direction Y parallel are connected to first bus 4051, a plurality of edges are connected to second bus 4052 second electrode strips 4054 of arranging along second direction Y parallel, first direction X with second direction Y is perpendicular, first electrode strip 4053 with second electrode strip 4054 staggered.
In this embodiment, the widths of first electrode strip 4053 and second electrode strip 4054 are equal; first electrode strip 4053 and second electrode strip 4054 have a first width dimension d1, the central axis of adjacent first electrode strip 4053 and second electrode strip 4054 have a first center dimension d2, and the ratio of first center dimension d2 to first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of first electrode strip 4053 and second electrode strip 4054 is equal to first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 405 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 405 is one or more layers. In this embodiment, the electrode structure 405 has two layers, and the material of the electrode structure 405 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 25, fig. 25 and fig. 24 are shown in the same view direction, a sacrificial layer 408 is formed on the piezoelectric layer 404, and the sacrificial layer 408 at least covers the electrode structure 405.
The material of the sacrificial layer 408 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the sacrificial layer 408 is polyimide.
Referring to fig. 26, an intermediate layer 401 is formed on the piezoelectric layer 404, the intermediate layer 401 at least covers the sacrificial layer 408, the intermediate layer 401 includes a first side 401a and a second side 401b opposite to each other, and the piezoelectric layer 404 and the sacrificial substrate 403 are located on the second side 401b.
The material of the intermediate layer 401 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 401 is silicon dioxide.
Referring to fig. 27, a substrate 400 is provided.
The material of the substrate 400 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 400.
Referring to fig. 28, the substrate 400 and the intermediate layer 401 are bonded, the substrate 400 is located on the first side 401a; after bonding the substrate 400 and the intermediate layer 401, the sacrificial substrate 403 is removed.
The process of removing the sacrificial substrate 403 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 403 adopts a physical grinding process.
In this embodiment, a bonding process is used to bond the substrate 400 and the intermediate layer 401; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 29 and 30, fig. 30 is a schematic cross-sectional view taken along line D-D in fig. 29, a frequency modulation layer 406 is formed on the second side 401b and on the piezoelectric layer 404, the middle layer 401 and the frequency modulation layer 406 are respectively located on two sides of the piezoelectric layer 404, and the electrode structure 405 and the frequency modulation layer 406 are respectively located on two sides of the piezoelectric layer 404.
The material of the tuning layer 406 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 406 is silicon nitride.
In this embodiment, the frequency modulation layer 406 includes a recess 407, and a projection of the electrode structure 405 on the substrate 400 is located within a projection range of the recess 407 on the substrate 400. By increasing or decreasing the depth of the concave groove 407, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 406 can control the frequency of the device more flexibly and accurately.
The concave groove 407 is in any polygon shape. In this embodiment, the concave slot 407 has a rectangular shape.
Referring to fig. 31, the view directions of fig. 31 and fig. 30 are the same, after the frequency modulation layer 406 is formed, the sacrificial layer 408 is removed, a cavity 402 is formed in the middle layer 401, an opening of the cavity 402 is located on the second side 401b, and the electrode structure 405 is located in the cavity 402.
In this embodiment, since the electrode structure 405 is located in the cavity 402, the piezoelectric layer 404 can provide a relatively flat surface for the formed frequency modulation layer 406, so as to reduce lattice defects of the thin film of the frequency modulation layer 406, and improve the quality of the thin film, thereby enabling the frequency modulation layer 406 to control the frequency of the device more flexibly and accurately. In addition, since the electrode structure 405 is located in the cavity 402, the electrode structure 405 can be effectively prevented from being oxidized or corroded in use of the device.
In this embodiment, the process of removing the sacrificial layer 408 is a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 31, which includes: a substrate 400; an intermediate layer 401, said intermediate layer 401 comprising opposing first and second sides 401a, 401b, said substrate 400 being located on said first side 401a, said intermediate layer 401 comprising a cavity 402, an opening of said cavity 402 being located on said second side 401b; an electrode structure 405 located within the cavity 402; a piezoelectric layer 404 located on said second side 401b and on said electrode structure 405, said piezoelectric layer 404 covering at least said cavity 405; the frequency modulation layer 406 is located on the second side 401b and located on the piezoelectric layer 404, the middle layer 401 and the frequency modulation layer 406 are respectively located on two sides of the piezoelectric layer 404, the electrode structure 405 and the frequency modulation layer 406 are respectively located on two sides of the piezoelectric layer 404, the frequency modulation layer 406 includes a recess 407, and a projection of the electrode structure 405 on the substrate 400 is located in a projection range of the recess 407 on the substrate 400.
In this embodiment, since the electrode structure 405 is located in the cavity 402, the piezoelectric layer 404 can provide a relatively flat surface for the formed frequency modulation layer 406, so as to reduce lattice defects of the thin film of the frequency modulation layer 406, and improve the quality of the thin film, thereby enabling the frequency modulation layer 406 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 405 is located in the cavity 402, the electrode structure 405 can be effectively prevented from being oxidized or corroded when the device is in use.
The material of the substrate 400 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 400 is made of silicon.
The material of the intermediate layer 401 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 401 is silicon dioxide.
The material of the piezoelectric layer 404 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 404.
In this embodiment, the electrode structure 405 includes: first bus 4051 and second bus 4052 of arranging along first direction X parallel, a plurality of first electrode strips 4053 of arranging along second direction Y parallel are connected to first bus 4051, a plurality of edges are connected to second bus 4052 second electrode strips 4054 of arranging along second direction Y parallel, first direction X with second direction Y is perpendicular, first electrode strip 4053 with second electrode strip 4054 staggered.
In this embodiment, the widths of first electrode strip 4053 and second electrode strip 4054 are equal; first electrode strip 4053 and second electrode strip 4054 have a first width dimension d1, the adjacent central axis of first electrode strip 4053 and second electrode strip 4054 has a first center dimension d2, and the ratio of first center dimension d2 to first width dimension d1 ranges from: 1.2 to 20.
In the present embodiment, the thickness of first electrode strip 4053 and second electrode strip 4054 is equal to first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 405 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 405 is one or more layers. In this embodiment, the electrode structure 405 has two layers, and the material of the electrode structure 405 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the tuning layer 406 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 406 is silicon nitride.
In this embodiment, by increasing or decreasing the depth of the concave slot 407, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 406 can control the device frequency more flexibly and accurately.
The concave groove 407 is in any polygon shape. In this embodiment, the concave slot 407 has a rectangular shape.
Fig. 32 to 42 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 32, a sacrificial substrate 503 is provided.
The material of the sacrificial substrate 503 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 503.
Referring to fig. 33, a piezoelectric layer 504 is formed on the sacrificial substrate 503.
The material of the piezoelectric layer 504 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 504.
Referring to fig. 34 and 35, fig. 35 is a schematic cross-sectional view taken along line E-E of fig. 34, wherein an electrode structure 505 is formed on the piezoelectric layer 504.
In this embodiment, the electrode structure 505 includes: the first bus 5051 and the second bus 5052 are arranged in parallel along a first direction X, the first bus 5051 is connected with a plurality of first electrode bars 5053 arranged in parallel along a second direction Y, the second bus 5052 is connected with a plurality of second electrode bars 5054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode bars 5053 and the second electrode bars 5054 are arranged in a staggered manner.
In this embodiment, the first electrode strip 5053 and the second electrode strip 5054 are equal in width; the first electrode strip 5053 and the second electrode strip 5054 have a first width dimension d1, the central axis of the first electrode strip 5053 and the central axis of the second electrode strip 5054 adjacent to each other have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode strip 5053 and the second electrode strip 5054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The materials of the electrode structure 505 include: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 505 is one or more layers. In this embodiment, the electrode structure 505 has two layers, and the material of the electrode structure 505 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 36, fig. 36 and fig. 35 are the same view direction, a sacrificial layer 508 is formed on the piezoelectric layer 504, and the sacrificial layer 508 covers at least the electrode structure 505.
The material of the sacrificial layer 508 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the sacrificial layer 508 is polyimide.
Referring to fig. 37, an intermediate layer 501 is formed on the piezoelectric layer 504, the intermediate layer 501 at least covers the sacrificial layer 508, the intermediate layer 501 includes a first side 501a and a second side 501b opposite to each other, and the piezoelectric layer 504 and the sacrificial substrate 503 are located on the second side 501b.
The material of the intermediate layer 501 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 501 is silicon dioxide.
Referring to fig. 37, a substrate 500 is provided.
The materials of the substrate 500 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 500.
Referring to fig. 39, the substrate 500 and the intermediate layer 501 are bonded, the substrate 500 is located at the first side 501a; after bonding the substrate 500 and the intermediate layer 501, the sacrificial substrate 503 is removed.
The process of removing the sacrificial substrate 503 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 503 is a physical grinding process.
In this embodiment, a bonding process is used to join the substrate 500 and the intermediate layer 501; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 40 and 41, fig. 41 is a schematic cross-sectional view taken along line F-F in fig. 40, and a frequency modulation layer 506 is formed on the second side 501b and on the piezoelectric layer 504, the middle layer 501 and the frequency modulation layer 506 are respectively located on two sides of the piezoelectric layer 504, and the electrode structure 505 and the frequency modulation layer 506 are respectively located on two sides of the piezoelectric layer 504.
The material of the frequency modulation layer 506 comprises metal or insulating dielectric; wherein the metal comprises: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 506 is silicon nitride.
In this embodiment, the frequency modulation region S of the frequency modulation layer 506 includes a plurality of grooves 507, and a projection of the electrode structure 505 on the substrate 500 is located within a projection range of the frequency modulation region S on the substrate 500. By increasing or decreasing the depth of the groove 507, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 506 can control the frequency of the device more flexibly and accurately.
In this embodiment, a plurality of the grooves 507 are uniformly distributed in the frequency modulation region.
The distribution of the grooves 507 can be any polygon or ring, and the single groove 507 is any polygon or circle. In this embodiment, a plurality of the grooves 507 are distributed in a rectangular shape, and a single groove 507 is also in a rectangular shape.
Referring to fig. 42, the views of fig. 42 and fig. 41 are in the same direction, after the frequency modulation layer 506 is formed, the sacrificial layer 508 is removed, a cavity 502 is formed in the middle layer 501, an opening of the cavity 502 is located on the second side 501b, and the electrode structure 505 is located in the cavity 502.
In this embodiment, since the electrode structure 505 is located in the cavity 502, the piezoelectric layer 504 can provide a relatively flat surface for the frequency modulation layer 506, so as to reduce lattice defects of the thin film of the frequency modulation layer 506 and improve the quality of the thin film, thereby enabling the frequency modulation layer 506 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 505 is located in the cavity 502, the electrode structure 505 can be effectively prevented from being oxidized or corroded in use of the device.
In this embodiment, the process of removing the sacrificial layer 506 is a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 42, which includes: a substrate 500; an intermediate layer 501, the intermediate layer 501 comprising a first side 501a and a second side 501b opposite to each other, the substrate 500 being located on the first side 501a, the intermediate layer 501 comprising a cavity 502, an opening of the cavity 502 being located on the second side 501b; an electrode structure 505 located within the cavity 502; a piezoelectric layer 504 located on said second side 501b and on said electrode structure 505, said piezoelectric layer 504 at least covering said cavity 505; the frequency modulation layer 506 is located on the second side 501b and located on the piezoelectric layer 504, the middle layer 501 and the frequency modulation layer 506 are located on two sides of the piezoelectric layer 504 respectively, the electrode structure 505 and the frequency modulation layer 506 are located on two sides of the piezoelectric layer 504 respectively, a frequency modulation area S of the frequency modulation layer 506 includes a plurality of grooves 507, and a projection of the electrode structure 505 on the substrate 500 is located in a projection range of the frequency modulation area S on the substrate 500.
In this embodiment, since the electrode structure 505 is located in the cavity 502, the piezoelectric layer 504 can provide a relatively flat surface for the frequency modulation layer 506, so as to reduce lattice defects of the thin film of the frequency modulation layer 506 and improve the quality of the thin film, thereby enabling the frequency modulation layer 506 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 505 is located in the cavity 502, the electrode structure 505 can be effectively prevented from being oxidized or corroded when the device is in use.
The materials of the substrate 500 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 500.
The material of the intermediate layer 501 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 501 is silicon dioxide.
The material of the piezoelectric layer 504 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 504.
In this embodiment, the electrode structure 505 includes: the first bus 5051 and the second bus 5052 are arranged in parallel along a first direction X, the first bus 5051 is connected with a plurality of first electrode bars 5053 arranged in parallel along a second direction Y, the second bus 5052 is connected with a plurality of second electrode bars 5054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode bars 5053 and the second electrode bars 5054 are arranged in a staggered manner.
In this embodiment, the first electrode strip 5053 and the second electrode strip 5054 are equal in width; the first electrode strip 5053 and the second electrode strip 5054 have a first width dimension d1, the central axis of the first electrode strip 5053 and the central axis of the second electrode strip 5054 adjacent to each other have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode strip 5053 and the second electrode strip 5054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The materials of the electrode structure 505 include: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 505 is one or more layers. In this embodiment, the electrode structure 505 has two layers, and the material of the electrode structure 505 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the frequency modulation layer 506 comprises metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 506 is silicon nitride.
In this embodiment, by increasing or decreasing the depth of the groove 507, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 506 can control the device frequency more flexibly and accurately.
In this embodiment, a plurality of the grooves 507 are uniformly distributed in the frequency modulation region.
The distribution of the grooves 507 can be any polygon or ring, and the single groove 507 is any polygon or circle. In this embodiment, a plurality of the grooves 507 are distributed in a rectangular shape, and a single groove 507 is also rectangular.
Fig. 43 to 53 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 43, a sacrificial substrate 603 is provided.
The material of the sacrificial substrate 603 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 603.
Referring to fig. 44, a piezoelectric layer 604 is formed on the sacrificial substrate 603.
The material of the piezoelectric layer 604 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 604 is made of lithium niobate.
Referring to fig. 45 and 46, fig. 46 is a schematic cross-sectional view taken along line G-G of fig. 45, wherein an electrode structure 605 is formed on the piezoelectric layer 604.
In this embodiment, the electrode structure 605 includes: the electrode structure comprises a first bus 6051 and a second bus 6052 which are arranged in parallel along a first direction X, wherein the first bus 6051 is connected with a plurality of first electrode strips 6053 which are arranged in parallel along a second direction Y, the second bus 6052 is connected with a plurality of second electrode strips 6054 which are arranged in parallel along the second direction Y, the first direction X is vertical to the second direction Y, and the first electrode strips 6053 and the second electrode strips 6054 are placed in a staggered mode.
In this embodiment, the widths of the first electrode bars 6053 and the second electrode bars 6054 are equal; the first electrode bar 6053 and the second electrode bar 6054 have a first width dimension d1, the central axis of the first electrode bar 6053 and the central axis of the second electrode bar 6054 that are adjacent to each other have a first central dimension d2, and the ratio range of the first central dimension d2 to the first width dimension d1 is: 1.2 to 20.
In the present embodiment, the thickness of the first electrode bars 6053 and the second electrode bars 6054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 605 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 605 is one or more layers. In this embodiment, the electrode structure 605 has two layers, and the material of the electrode structure 605 is molybdenum aluminum, tungsten aluminum or platinum aluminum.
Referring to fig. 47, fig. 47 and fig. 45 are shown in the same view direction, a sacrificial layer 608 is formed on the piezoelectric layer 604, and the sacrificial layer 608 covers at least the electrode structure 605.
The material of the sacrificial layer 608 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the sacrificial layer 608 is polyimide.
Referring to fig. 48, an intermediate layer 601 is formed on the piezoelectric layer 604, the intermediate layer 601 at least covers the sacrificial layer 608, the intermediate layer 601 includes a first side 601a and a second side 601b opposite to each other, and the piezoelectric layer 604 and the sacrificial substrate 603 are located on the second side 601b.
The material of the intermediate layer 601 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 601 is silicon dioxide.
Referring to fig. 49, a substrate 600 is provided.
The material of the substrate 600 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 600 is made of silicon.
Referring to fig. 50, the substrate 600 and the intermediate layer 601 are bonded, the substrate 600 is located on the first side 601a; after bonding the substrate 600 and the intermediate layer 601, the sacrificial substrate 603 is removed.
The process of removing the sacrificial substrate 603 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 603 adopts a physical polishing process.
In this embodiment, a bonding process is used to join the substrate 600 and the intermediate layer 601; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 51, a temperature compensation layer 607 is formed on the second side 601a and on the piezoelectric layer 604.
The material of the temperature compensation layer 607 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 607 is silicon dioxide.
In this embodiment, since the temperature compensation layer 607 and the piezoelectric layer 604 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device frequency is reduced to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
Referring to fig. 52, a frequency modulation layer 606 is formed, located on the second side 601b and located on the temperature compensation layer 607, the projection of the electrode structure 605 on the substrate 600 is located in the projection range of the frequency modulation layer 606 on the substrate 600, and the piezoelectric layer 604 and the frequency modulation layer 606 are respectively located on two sides of the temperature compensation layer 607.
The material of the frequency modulation layer 606 comprises a metal or an insulating dielectric; wherein the metal comprises: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the frequency modulation layer 606 is made of silicon nitride.
Referring to fig. 53, after the frequency modulation layer 606 is formed, the sacrificial layer 608 is removed, a cavity 602 is formed in the middle layer 601, an opening of the cavity 602 is located on the second side 601b, and the electrode structure 605 is located in the cavity 602.
In this embodiment, since the electrode structure 605 is located in the cavity 602, the piezoelectric layer 604 can provide a relatively flat surface for the formed frequency modulation layer 606, so as to reduce lattice defects of the thin film of the frequency modulation layer 606, improve the quality of the thin film, and further enable the frequency modulation layer 606 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 605 is located in the cavity 602, the electrode structure 605 can be effectively prevented from being oxidized or corroded in use of the device.
In this embodiment, the process of removing the sacrificial layer 608 is a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 53, which includes: a substrate 600; an intermediate layer 601, said intermediate layer 601 comprising a first side 601a and a second side 601b opposite to each other, said substrate 600 being located at said first side 601a, said intermediate layer 601 comprising a cavity 602, an opening of said cavity 602 being located at said second side 601b; an electrode structure 605 located within the cavity 602; a piezoelectric layer 604 on said second side 601b and on said electrode structure 605, said piezoelectric layer 604 at least covering said cavity 605; a temperature compensation layer 607 on the second side 601b and on the piezoelectric layer 604; the frequency modulation layer 606 is located on the second side 601b and located on the piezoelectric layer 604, a projection of the electrode structure 605 on the substrate 600 is located in a projection range of the frequency modulation layer 606 on the substrate 600, the middle layer 601 and the frequency modulation layer 606 are respectively located on two sides of the piezoelectric layer 604, and the piezoelectric layer 604 and the frequency modulation layer 606 are respectively located on two sides of the temperature compensation layer 607.
In this embodiment, since the electrode structure 605 is located in the cavity 602, the piezoelectric layer 604 can provide a relatively flat surface for the formed frequency modulation layer 606, so as to reduce lattice defects of the thin film of the frequency modulation layer 606, improve the quality of the thin film, and further enable the frequency modulation layer 606 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 605 is located in the cavity 602, the electrode structure 605 can be effectively prevented from being oxidized or corroded during the use of the device.
The material of the substrate 600 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 600 is made of silicon.
The material of the intermediate layer 601 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 601 is silicon dioxide.
The material of the piezoelectric layer 604 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 604 is made of lithium niobate.
In this embodiment, the electrode structure 605 includes: the electrode structure comprises a first bus 6051 and a second bus 6052 which are arranged in parallel along a first direction X, wherein the first bus 6051 is connected with a plurality of first electrode strips 6053 which are arranged in parallel along a second direction Y, the second bus 6052 is connected with a plurality of second electrode strips 6054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 6053 and the second electrode strips 6054 are placed in a staggered mode.
In this embodiment, the widths of the first electrode bars 6053 and the second electrode bars 6054 are equal; the first electrode bar 6053 and the second electrode bar 6054 have a first width dimension d1, the central axis of the first electrode bar 6053 and the central axis of the second electrode bar 6054 that are adjacent to each other have a first central dimension d2, and the ratio range of the first central dimension d2 to the first width dimension d1 is: 1.2 to 20 parts by weight.
In the present embodiment, the thickness of the first electrode bars 6053 and the second electrode bars 6054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 605 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 605 is one or more layers. In this embodiment, the electrode structure 605 has two layers, and the material of the electrode structure 605 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the frequency modulation layer 606 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the frequency modulation layer 606 is made of silicon nitride.
The material of the temperature compensation layer 607 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 607 is silicon dioxide.
In this embodiment, since the temperature compensation layer 607 and the piezoelectric layer 604 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device is decreased and tends to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
Fig. 54 to 65 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 54, a sacrificial substrate 703 is provided.
The material of the sacrificial substrate 703 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 703.
Referring to fig. 55, a piezoelectric layer 704 is formed on the sacrificial substrate 703.
The material of the piezoelectric layer 704 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 704 is made of lithium niobate.
Referring to fig. 56 and 57, fig. 57 is a schematic cross-sectional view taken along line H-H in fig. 56, and an electrode structure 705 is formed on the piezoelectric layer 704.
In this embodiment, the electrode structure 705 includes: the electrode structure comprises a first bus 7051 and a second bus 7052 which are arranged in parallel along a first direction X, wherein the first bus 7051 is connected with a plurality of first electrode strips 7053 which are arranged in parallel along a second direction Y, the second bus 7052 is connected with a plurality of second electrode strips 7054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 7053 and the second electrode strips 7054 are arranged in a staggered mode.
In this embodiment, the widths of the first electrode stripes 7053 and the second electrode stripes 7054 are equal; the first electrode stripes 7053 and the second electrode stripes 7054 have a first width dimension d1, the central axes of the adjacent first electrode stripes 7053 and the central axes of the adjacent second electrode stripes 7054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20 parts by weight.
In the present embodiment, the thickness of the first electrode stripes 7053 and the second electrode stripes 7054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 705 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 705 is one or more layers. In this embodiment, the electrode structure 705 is two layers, and the material of the electrode structure 705 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 58, fig. 58 and fig. 57 are shown in the same view direction, a sacrificial layer 709 is formed on the piezoelectric layer 704, and the sacrificial layer 709 at least covers the electrode structure 705.
The material of the sacrificial layer 709 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, polyimide is used as the material of the sacrificial layer 709.
Referring to fig. 59, an intermediate layer 701 is formed on the piezoelectric layer 704, the intermediate layer 701 covers at least the sacrificial layer 709, the intermediate layer 701 includes a first side 701a and a second side 701b opposite to each other, and the piezoelectric layer 704 and the sacrificial substrate 703 are located on the second side 701b.
The material of the intermediate layer 701 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 701 is silicon dioxide.
Referring to fig. 60, a substrate 700 is provided.
The material of the substrate 700 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 700 is made of silicon.
Referring to fig. 61, the substrate 700 and the intermediate layer 701 are bonded, the substrate 700 is located on the first side 701a; after bonding the substrate 700 and the intermediate layer 701, the sacrificial substrate 703 is removed.
The process of removing the sacrificial substrate 703 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 703 adopts a physical polishing process.
In this embodiment, a bonding process is used to join the substrate 700 and the intermediate layer 701; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 62, a temperature compensation layer 708 is formed on the second side 701a and on the piezoelectric layer 704.
The material of the temperature compensation layer 708 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 708 is silicon dioxide.
In this embodiment, since the temperature compensation layer 708 and the piezoelectric layer 704 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device frequency is reduced to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
Referring to fig. 63 and 64, fig. 64 is a schematic view of a cross section along line I-I in fig. 63, a frequency modulation layer 706 is formed on the second side 701b and on the temperature compensation layer 708, and the piezoelectric layer 704 and the frequency modulation layer 706 are respectively located on two sides of the temperature compensation layer 708.
The material of the fm layer 706 includes metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 706 is silicon nitride.
In this embodiment, the frequency modulation layer 706 comprises a recess 707, and a projection of the electrode structure 705 on the substrate 700 is located within a projection range of the recess 707 on the substrate 700. By increasing or decreasing the depth of the groove 707, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 706 can control the frequency of the device more flexibly and accurately.
The groove 707 has an arbitrary polygonal shape. In this embodiment, the groove 707 has a rectangular shape.
Referring to fig. 65, the view directions of fig. 65 and fig. 64 are the same, after the frequency modulation layer 706 is formed, the sacrificial layer 709 is removed, a cavity 702 is formed in the middle layer 701, an opening of the cavity 702 is located on the second side 701b, and the electrode structure 705 is located in the cavity 702.
In this embodiment, since the electrode structure 705 is located in the cavity 702, the piezoelectric layer 704 can provide a relatively flat surface for the formed frequency modulation layer 706, so as to reduce lattice defects of the thin film of the frequency modulation layer 706, improve the quality of the thin film, and further enable the frequency modulation layer 706 to be more flexible and accurate for controlling the frequency of the device. In addition, because the electrode structure 705 is located in the cavity 702, the electrode structure 705 can be effectively prevented from being oxidized or corroded in use of the device.
In this embodiment, the process of removing the sacrificial layer 709 adopts a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 65, which includes: a substrate 700; an intermediate layer 701, said intermediate layer 701 comprising a first side 701a and a second side 701b opposite to each other, said substrate 700 being located on said first side 701a, said intermediate layer 701 comprising a cavity 702, an opening of said cavity 702 being located on said second side 701b; an electrode structure 705 located within the cavity 702; a piezoelectric layer 704 located on said second side 701b and on said electrode structure 705, said piezoelectric layer 704 at least covering said cavity 705; a temperature compensation layer 708 on the second side 701b and on the piezoelectric layer 704; the frequency modulation layer 706 is located on the second side 701b and on the piezoelectric layer 704, the middle layer 701 and the frequency modulation layer 706 are respectively located on two sides of the piezoelectric layer 704, the piezoelectric layer 704 and the frequency modulation layer 706 are respectively located on two sides of the temperature compensation layer 708, the frequency modulation layer 706 includes a groove 707, and a projection of the electrode structure 705 on the substrate 700 is located in a projection range of the groove 707 on the substrate 700.
In this embodiment, since the electrode structure 705 is located in the cavity 702, the piezoelectric layer 704 can provide a relatively flat surface for the formed frequency modulation layer 706, so as to reduce lattice defects of the thin film of the frequency modulation layer 706, improve the quality of the thin film, and further enable the frequency modulation layer 706 to be more flexible and accurate for controlling the frequency of the device. In addition, because the electrode structure 705 is located in the cavity 702, the electrode structure 705 can be effectively prevented from being oxidized or corroded in use of the device.
The material of the substrate 700 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the substrate 700 is made of silicon.
The material of the intermediate layer 701 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 701 is silicon dioxide.
The material of the piezoelectric layer 704 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 704 is made of lithium niobate.
In this embodiment, the electrode structure 705 includes: the electrode structure comprises a first bus 7051 and a second bus 7052 which are arranged in parallel along a first direction X, wherein the first bus 7051 is connected with a plurality of first electrode strips 7053 which are arranged in parallel along a second direction Y, the second bus 7052 is connected with a plurality of second electrode strips 7054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 7053 and the second electrode strips 7054 are arranged in a staggered mode.
In this embodiment, the widths of the first electrode stripes 7053 and the second electrode stripes 7054 are equal; the first electrode stripes 7053 and the second electrode stripes 7054 have a first width dimension d1, the central axes of the adjacent first electrode stripes 7053 and the central axes of the adjacent second electrode stripes 7054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20 parts by weight.
In this embodiment, the thickness of the first electrode stripes 7053 and the second electrode stripes 7054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 705 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 705 is one or more layers. In this embodiment, the electrode structure 705 has two layers, and the material of the electrode structure 705 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the fm layer 706 includes metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 706 is silicon nitride.
In this embodiment, by increasing or decreasing the depth of the groove 707, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 706 can control the device frequency more flexibly and accurately.
The groove 707 has an arbitrary polygonal shape. In this embodiment, the groove 707 has a rectangular shape.
The material of the temperature compensation layer 708 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 708 is silicon dioxide.
In this embodiment, since the temperature compensation layer 708 and the piezoelectric layer 704 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device frequency is reduced to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
Fig. 66 to 77 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 66, a sacrificial substrate 803 is provided.
The material of the sacrificial substrate 803 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 803.
Referring to fig. 67, a piezoelectric layer 804 is formed on the sacrificial substrate 803.
The material of the piezoelectric layer 804 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 804.
Referring to fig. 68 and 69, fig. 69 is a schematic cross-sectional view taken along line J-J of fig. 68, wherein an electrode structure 805 is formed on the piezoelectric layer 804.
In this embodiment, the electrode structure 805 includes: the electrode structure comprises a first bus 8051 and a second bus 8052 which are arranged in parallel along a first direction X, wherein the first bus 8051 is connected with a plurality of first electrode strips 8053 which are arranged in parallel along a second direction Y, the second bus 8052 is connected with a plurality of second electrode strips 8054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 8053 and the second electrode strips 8054 are arranged in a staggered mode.
In the present embodiment, the widths of the first electrode stripes 8053 and the second electrode stripes 8054 are equal; the first electrode strip 8053 and the second electrode strip 8054 have a first width dimension d1, the adjacent central axis of the first electrode strip 8053 and the central axis of the second electrode strip 8054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20 parts by weight.
In the present embodiment, the thickness of the first electrode strip 8053 and the second electrode strip 8054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 805 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 805 is one or more layers. In this embodiment, the electrode structure 805 is two layers, and the material of the electrode structure 805 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 70, the view directions of fig. 70 and fig. 69 are the same, a sacrificial layer 809 is formed on the piezoelectric layer 804, and the sacrificial layer 809 covers at least the electrode structure 805.
The material of the sacrificial layer 809 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, polyimide is used as the material of the sacrificial layer 809.
Referring to fig. 71, an intermediate layer 801 is formed on the piezoelectric layer 804, the intermediate layer 801 at least covers the sacrificial layer 809, the intermediate layer 801 includes a first side 801a and a second side 801b opposite to each other, and the piezoelectric layer 804 and the sacrificial substrate 803 are located on the second side 801b.
The material of the intermediate layer 801 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 801 is silicon dioxide.
Referring to fig. 72, a substrate 800 is provided.
The material of the substrate 800 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 800.
Referring to fig. 73, the substrate 800 and the intermediate layer 801 are bonded, the substrate 800 is located on the first side 801a; after bonding the substrate 800 and the intermediate layer 801, the sacrificial substrate 803 is removed.
The process of removing the sacrificial substrate 803 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 803 is a physical grinding process.
In this embodiment, a bonding process is used to join the substrate 800 and the intermediate layer 801; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 74, a temperature compensation layer 808 is formed on the piezoelectric layer 804 at the second side 801b.
The material of the temperature compensation layer 808 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 808 is silicon dioxide.
In this embodiment, since the temperature compensation layer 808 and the piezoelectric layer 804 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device is reduced to 0 ppm/degree centigrade, so as to improve the frequency-temperature stability of the resonant device.
Referring to fig. 75 and 76, fig. 76 is a schematic cross-sectional view taken along the line K-K in fig. 75, and a frequency modulation layer 806 is formed on the second side 801b and on the piezoelectric layer 804, the middle layer 801 and the frequency modulation layer 806 are respectively located on two sides of the piezoelectric layer 804, and the electrode structure 805 and the frequency modulation layer 806 are respectively located on two sides of the piezoelectric layer 804.
The material of the frequency tuning layer 806 includes metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the frequency modulation layer 806 is made of silicon nitride.
In this embodiment, the frequency modulation region S of the frequency modulation layer 806 comprises a plurality of grooves 807, and a projection of the electrode structure 805 on the substrate 800 is located within a projection range of the frequency modulation region S on the substrate 800. By increasing or decreasing the depth of the groove 807, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 806 can control the device frequency more flexibly and accurately.
In this embodiment, the grooves 807 are uniformly distributed in the frequency modulation region.
The distribution of the plurality of grooves 807 can be any polygon or ring shape, and the single groove 807 can be any polygon or circle shape. In this embodiment, a plurality of the grooves 807 are distributed in a rectangular shape, and a single groove 807 is also rectangular.
Referring to fig. 77, the view directions of fig. 77 and fig. 76 are the same, after the frequency modulation layer 806 is formed, the sacrificial layer 809 is removed, a cavity 802 is formed in the intermediate layer 801, an opening of the cavity 802 is located on the second side 801b, and the electrode structure 805 is located in the cavity 802.
In this embodiment, since the electrode structure 805 is located in the cavity 802, the piezoelectric layer 804 can provide a relatively flat surface for the formed frequency modulation layer 806, so as to reduce lattice defects of the thin film of the frequency modulation layer 806, and improve the quality of the thin film, thereby enabling the frequency modulation layer 806 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structures 805 are located in the cavities 802, the electrode structures 805 can be effectively prevented from being oxidized or corroded in use of the device.
In this embodiment, the process of removing the sacrificial layer 809 adopts a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 77 including: a substrate 800; an intermediate layer 801, said intermediate layer 801 comprising opposing first and second sides 801a, 801b, said substrate 800 being located on said first side 801a, said intermediate layer 801 comprising a cavity 802, said cavity 802 opening being located on said second side 801b; an electrode structure 805 located within the cavity 802; a piezoelectric layer 804 located on the second side 801b and on the electrode structure 805, the piezoelectric layer 804 at least covering the cavity 802; a temperature compensation layer 808 on the second side 801b and on the piezoelectric layer 804; a frequency modulation layer 806 located on the second side 801b and on the piezoelectric layer 804, wherein the middle layer 801 and the frequency modulation layer 806 are respectively located on two sides of the piezoelectric layer 804, the piezoelectric layer 804 and the frequency modulation layer 806 are respectively located on two sides of the temperature compensation layer 808, a frequency modulation area S of the frequency modulation layer 806 includes a plurality of grooves 807, and a projection of the electrode structure 805 on the substrate 800 is located within a projection range of the frequency modulation area S on the substrate 800.
In this embodiment, since the electrode structure 805 is located in the cavity 802, the piezoelectric layer 804 can provide a relatively flat surface for the formed frequency modulation layer 806, so as to reduce lattice defects of the thin film of the frequency modulation layer 806, and improve the quality of the thin film, thereby enabling the frequency modulation layer 806 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structures 805 are located in the cavities 802, the electrode structures 805 can be effectively prevented from being oxidized or corroded during the use of the device.
The material of the substrate 800 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 800.
The material of the intermediate layer 801 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 801 is silicon dioxide.
The material of the piezoelectric layer 804 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 804 is made of lithium niobate.
In this embodiment, the electrode structure 805 includes: the electrode structure comprises a first bus 8051 and a second bus 8052 which are arranged in parallel along a first direction X, wherein the first bus 8051 is connected with a plurality of first electrode strips 8053 which are arranged in parallel along a second direction Y, the second bus 8052 is connected with a plurality of second electrode strips 8054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 8053 and the second electrode strips 8054 are arranged in a staggered mode.
In the present embodiment, the widths of the first electrode stripes 8053 and the second electrode stripes 8054 are equal; the first electrode strips 8053 and the second electrode strips 8054 have a first width dimension d1, the adjacent central axes of the first electrode strips 8053 and the second electrode strips 8054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In the present embodiment, the thickness of the first electrode strip 8053 and the second electrode strip 8054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 805 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 805 is one or more layers. In this embodiment, the electrode structure 805 is two layers, and the material of the electrode structure 805 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the frequency modulation layer 806 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the frequency modulation layer 806 is made of silicon nitride.
In this embodiment, by increasing or decreasing the depth of the groove 807, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 806 can control the device frequency more flexibly and accurately.
In this embodiment, the grooves 807 are uniformly distributed in the frequency modulation region.
The distribution of the plurality of grooves 807 may be any polygon or ring shape, and the single groove 807 may be any polygon or circle shape. In the present embodiment, a plurality of the grooves 807 are distributed in a rectangular shape, and a single groove 807 is also rectangular.
The material of the temperature compensation layer 808 comprises: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 808 is silicon dioxide.
In this embodiment, since the temperature compensation layer 808 and the piezoelectric layer 804 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device frequency is reduced to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
Fig. 78 to 88 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator in accordance with another embodiment of the present invention.
Referring to fig. 78, a sacrificial substrate 903 is provided.
The material of the sacrificial substrate 903 comprises: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 903.
Referring to fig. 79, a piezoelectric layer 904 is formed on the sacrificial substrate 903.
The material of the piezoelectric layer 904 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 904.
Referring to fig. 80 and 81, fig. 81 is a schematic cross-sectional view taken along line L-L of fig. 80, wherein an electrode structure 905 is formed on the piezoelectric layer 904.
In this embodiment, the electrode structure 905 includes: the electrode structure comprises a first bus 9051 and a second bus 9052 which are arranged in parallel along a first direction X, wherein the first bus 9051 is connected with a plurality of first electrode strips 9053 which are arranged in parallel along a second direction Y, the second bus 9052 is connected with a plurality of second electrode strips 9054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 9053 and the second electrode strips 9054 are arranged in a staggered mode.
In this embodiment, the widths of the first electrode strip 9053 and the second electrode strip 9054 are equal; the first electrode bar 9053 and the second electrode bar 9054 have a first width dimension d1, a central axis of the first electrode bar 9053 and a central axis of the second electrode bar 9054 which are adjacent to each other have a first central dimension d2, and a ratio range of the first central dimension d2 to the first width dimension d1 is as follows: 1.2 to 20.
In this embodiment, the thickness of the first electrode bar 9053 and the second electrode bar 9054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 905 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 905 is one or more layers. In this embodiment, the electrode structure 905 has two layers, and the material of the electrode structure 905 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 82, the views of fig. 82 and 81 are aligned, and a temperature compensation layer 907 is formed on the piezoelectric layer 904 and at least covers the electrode structure 905.
The material of the temperature compensation layer 907 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 907 is silicon dioxide.
In this embodiment, since the temperature compensation layer 907 and the piezoelectric layer 904 have opposite temperature frequency shift characteristics, the temperature coefficient of the frequency of the resonant device is reduced to tend to 0 ppm/DEG C, thereby improving the frequency-temperature stability of the resonant device.
In this embodiment, the temperature compensation layer 907 covers a portion of the piezoelectric layer 904; in other embodiments, the temperature compensation layer may also completely cover the piezoelectric layer.
Referring to fig. 83, a sacrificial layer 908 is formed on the piezoelectric layer 904, wherein the sacrificial layer 908 covers at least the temperature compensation layer 907.
The material of the sacrificial layer 908 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the sacrificial layer 908 is polyimide.
In this embodiment, since the temperature compensation layer 907 covers a portion of the piezoelectric layer 904, forming the sacrificial layer 908 also covers a portion of the piezoelectric layer 904; in other embodiments, the sacrificial layer is not in contact with the piezoelectric layer when the temperature compensation layer completely covers the piezoelectric layer.
Referring to fig. 84, an intermediate layer 901 is formed on the piezoelectric layer 904, the intermediate layer 901 at least covers the sacrificial layer 908, the intermediate layer 901 includes a first side 901a and a second side 901b opposite to each other, and the piezoelectric layer 904 and the sacrificial substrate 903 are located on the second side 901b.
The material of the intermediate layer 901 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 901 is silicon dioxide.
Referring to fig. 85, a substrate 900 is provided.
The materials of the substrate 900 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 900.
Referring to fig. 86, the substrate 900 and the intermediate layer 901 are bonded, the substrate 900 is located on the first side 901a; after bonding the substrate 900 and the intermediate layer 901, the sacrificial substrate 903 is removed.
The process of removing the sacrificial substrate 903 comprises: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 903 is a physical polishing process.
In this embodiment, a bonding process is used to bond the substrate 900 and the intermediate layer 901; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 87, a frequency modulation layer 906 is formed, located on the second side 901b and located on the piezoelectric layer 904, a projection of the electrode structure 905 on the substrate 900 is located in a projection range of the frequency modulation layer 906 on the substrate 900, the middle layer 901 and the frequency modulation layer 906 are respectively located on two sides of the piezoelectric layer 904, and the electrode structure 904 and the frequency modulation layer 906 are respectively located on two sides of the piezoelectric layer 904.
The material of the tuning layer 906 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 906 is silicon nitride.
Referring to fig. 88, after the frequency modulation layer 906 is formed, the sacrificial layer 907 is removed, a cavity 902 is formed in the middle layer 901, an opening of the cavity 902 is located on the second side 901b, and the electrode structure 905 is located in the cavity 902.
In this embodiment, since the electrode structure 905 is located in the cavity 902, the piezoelectric layer 904 can provide a relatively flat surface for the frequency modulation layer 906, so as to reduce lattice defects of the thin film of the frequency modulation layer 906, and improve the quality of the thin film, thereby enabling the frequency modulation layer 906 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 905 is located in the cavity 902, the electrode structure 905 can be effectively prevented from being oxidized or corroded when the device is in use.
In this embodiment, after removing the sacrificial layer 908, the temperature compensation layer 907 is located within the cavity 902 and the piezoelectric layer 904 is located on the temperature compensation layer 907.
In this embodiment, the process of removing the sacrificial layer 908 adopts a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 88, which includes: a substrate 900; an intermediate layer 901, the intermediate layer 901 comprising a first side 901a and a second side 901b opposite to each other, the substrate 900 being located on the first side 901a, the intermediate layer 901 comprising a cavity 902, an opening of the cavity 902 being located on the second side 901b; an electrode structure 905 located within the cavity 902; a piezoelectric layer 904 located on said second side 901b and on said electrode structure 905, said piezoelectric layer 904 at least covering said cavity 905; a temperature compensation layer 907 located within the cavity 902 and covering at least the electrode structure 905, the piezoelectric layer 904 being located on the temperature compensation layer 907; the frequency modulation layer 906 is located on the second side 901b and located on the piezoelectric layer 904, a projection of the electrode structure 905 on the substrate 900 is located in a projection range of the frequency modulation layer 906 on the substrate 900, the middle layer 901 and the frequency modulation layer 907 are located on two sides of the piezoelectric layer 904 respectively, and the electrode structure 905 and the frequency modulation layer 906 are located on two sides of the piezoelectric layer 904 respectively.
In this embodiment, since the electrode structure 905 is located in the cavity 902, the piezoelectric layer 904 can provide a relatively flat surface for the frequency modulation layer 906, so as to reduce lattice defects of the thin film of the frequency modulation layer 906, and improve the quality of the thin film, thereby enabling the frequency modulation layer 906 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 905 is located in the cavity 902, the electrode structure 905 can be effectively prevented from being oxidized or corroded in use of the device.
The materials of the substrate 900 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 900.
The material of the intermediate layer 901 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 901 is silicon dioxide.
The material of the piezoelectric layer 904 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 904.
In this embodiment, the electrode structure 905 includes: the electrode structure comprises a first bus 9051 and a second bus 9052 which are arranged in parallel along a first direction X, wherein the first bus 9051 is connected with a plurality of first electrode strips 9053 which are arranged in parallel along a second direction Y, the second bus 9052 is connected with a plurality of second electrode strips 9054 which are arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 9053 and the second electrode strips 9054 are arranged in a staggered mode.
In this embodiment, the widths of the first electrode strip 9053 and the second electrode strip 9054 are equal; the first electrode strips 9053 and the second electrode strips 9054 have a first width dimension d1, the central axes of the adjacent first electrode strips 9053 and second electrode strips 9054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode bar 9053 and the second electrode bar 9054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 905 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 905 is one or more layers. In this embodiment, the electrode structure 905 has two layers, and the material of the electrode structure 905 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the tuning layer 906 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 906 is silicon nitride.
The material of the temperature compensation layer 907 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 907 is silicon dioxide.
In this embodiment, since the temperature compensation layer 907 and the piezoelectric layer 904 have opposite temperature frequency shift characteristics, the temperature coefficient of the frequency of the resonant device is reduced to tend to 0 ppm/DEG C, thereby improving the frequency-temperature stability of the resonant device.
Fig. 89 to 100 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 89, a sacrificial substrate 1003 is provided.
The material of the sacrificial substrate 1003 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, the sacrificial substrate 1003 is made of silicon.
Referring to fig. 90, a piezoelectric layer 1004 is formed on the sacrificial substrate 1003.
The material of the piezoelectric layer 1004 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, lithium niobate is used as the material of the piezoelectric layer 1004.
Referring to fig. 91 and 92, fig. 92 is a cross-sectional view taken along the M-M line in fig. 91, and an electrode structure 1005 is formed on the piezoelectric layer 1004.
In this embodiment, the electrode structure 1005 includes: the first bus 10051 and the second bus 10052 are arranged in parallel along a first direction X, the first bus 10051 is connected to a plurality of first electrode strips 10053 arranged in parallel along a second direction Y, the second bus 10052 is connected to a plurality of second electrode strips 10054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 10053 and the second electrode strips 10054 are disposed in a staggered manner.
In this embodiment, the widths of the first electrode stripes 10053 and the second electrode stripes 10054 are equal; the first electrode bar 10053 and the second electrode bar 10054 have a first width dimension d1, the central axis of the adjacent first electrode bar 10053 and the central axis of the second electrode bar 10054 have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode bar 10053 and the second electrode bar 10054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 1005 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 1005 is one or more layers. In this embodiment, the electrode structure 1005 has two layers, and the material of the electrode structure 1005 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 93, the views of fig. 93 and fig. 92 are aligned to form a temperature compensation layer 1008 on the piezoelectric layer 1004 and covering at least the electrode structure 1005.
The material of the temperature compensation layer 1008 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 1008 is silicon dioxide.
In this embodiment, since the temperature compensation layer 1008 and the piezoelectric layer 1004 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device is reduced to 0 ppm/degree centigrade, so as to improve the frequency-temperature stability of the resonant device.
In this embodiment, the temperature compensation layer 1008 covers a portion of the piezoelectric layer 1004; in other embodiments, the temperature compensation layer may also completely cover the piezoelectric layer.
Referring to fig. 94, a sacrificial layer 1009 is formed on the piezoelectric layer 1004, and the sacrificial layer 1009 at least covers the temperature compensation layer 1008.
The material of the sacrificial layer 1009 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, polyimide is used as the material of the sacrificial layer 1009.
In this embodiment, since the temperature compensation layer 1008 covers part of the piezoelectric layer 1004, forming the sacrificial layer 1009 also covers part of the piezoelectric layer 1004; in other embodiments, the sacrificial layer is not in contact with the piezoelectric layer when the temperature compensation layer completely covers the piezoelectric layer.
Referring to fig. 95, an intermediate layer 1001 is formed on the piezoelectric layer 1004, the intermediate layer 1001 covers at least the sacrificial layer 1009, the intermediate layer 1001 includes a first side 1001a and a second side 1001b opposite to each other, and the piezoelectric layer 1004 and the sacrificial substrate 1003 are located on the second side 1001b.
The material of the intermediate layer 1001 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 1001 is silicon dioxide.
Referring to fig. 96, a substrate 1000 is provided.
The materials of the substrate 1000 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 1000.
Referring to fig. 97, the substrate 1000 and the intermediate layer 1001 are bonded, the substrate 1000 is located on the first side 1001a; after bonding the substrate 1000 and the intermediate layer 1001, the sacrificial substrate 1003 is removed.
The process of removing the sacrificial substrate 1003 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 1003 adopts a physical grinding process.
In this embodiment, a bonding process is used to join the substrate 1000 and the intermediate layer 1001; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 98 and 99, fig. 99 is a schematic cross-sectional view along the line N-N in fig. 98, a frequency modulation layer 1006 is formed on the second side 1001b and on the piezoelectric layer 1004, the middle layer 1001 and the frequency modulation layer 1006 are respectively located on two sides of the piezoelectric layer 1004, and the electrode structure 1004 and the frequency modulation layer 1006 are respectively located on two sides of the piezoelectric layer 1004.
The material of the fm layer 1006 comprises a metal or an insulating dielectric; wherein the metal comprises: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the fm layer 1006 is silicon nitride.
In this embodiment, the fm layer 1006 includes a groove 1007, and a projection of the electrode structure 1005 on the substrate 1000 is located within a projection range of the groove 1007 on the substrate 1000. By increasing or decreasing the depth of the groove 1007, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 1006 can control the device frequency more flexibly and accurately.
The groove 1007 is in the shape of any polygon. In this embodiment, the groove 1007 is rectangular.
Referring to fig. 100, the views of fig. 100 and fig. 99 are the same, after the frequency modulation layer 1006 is formed, the sacrificial layer 1007 is removed, a cavity 1002 is formed in the middle layer 1001, an opening of the cavity 1002 is located on the second side 1001b, and the electrode structure 1005 is located in the cavity 1002.
In this embodiment, since the electrode structure 1005 is located in the cavity 1002, the piezoelectric layer 1004 can provide a relatively flat surface for the formed frequency modulation layer 1006, so as to reduce lattice defects of the thin film of the frequency modulation layer 1006, improve the quality of the thin film, and further enable the frequency modulation layer 1006 to control the frequency of the device more flexibly and accurately. In addition, since the electrode structure 1005 is located in the cavity 1002, the electrode structure 1005 can be effectively prevented from being oxidized or corroded during the use of the device.
In this embodiment, after removing the sacrificial layer 1009, the temperature compensation layer 1008 is located within the cavity 1002 and the piezoelectric layer 1004 is located on the temperature compensation layer 1008.
In this embodiment, the process of removing the sacrificial layer 1006 is a wet etching process.
Accordingly, the present invention further provides a bulk acoustic wave resonator, please refer to fig. 100, which includes: a substrate 1000; an intermediate layer 1001, said intermediate layer 1001 including a first side 1001a and a second side 1001b opposite to each other, said substrate 1000 being located on said first side 1001a, said intermediate layer 1001 including a cavity 1002, an opening of said cavity 1002 being located on said second side 1001b; an electrode structure 1005 located within the cavity 1002; a piezoelectric layer 1004 on the second side 1001b and on the electrode structure 1005, the piezoelectric layer 1004 at least covering the cavity 1002; a temperature compensation layer 1008 positioned within the cavity 1002 and covering at least the electrode structure 1005, the piezoelectric layer 1004 positioned on the temperature compensation layer 1008; the frequency modulation layer 1006 is located on the second side 1001b and on the piezoelectric layer 1004, the middle layer 1001 and the frequency modulation layer 1006 are respectively located on two sides of the piezoelectric layer 1004, the electrode structure 1005 and the frequency modulation layer 1006 are respectively located on two sides of the piezoelectric layer 1004, the frequency modulation layer 1006 includes a groove 1007, and a projection of the electrode structure 1005 on the substrate 100 is located within a projection range of the groove 1007 on the substrate 1000.
In this embodiment, since the electrode structure 1005 is located in the cavity 1002, the piezoelectric layer 1004 can provide a relatively flat surface for the formed frequency modulation layer 1006, so as to reduce lattice defects of the thin film of the frequency modulation layer 1006, improve the quality of the thin film, and further enable the frequency modulation layer 1006 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 1005 is located in the cavity 1002, the electrode structure 1005 can be effectively prevented from being oxidized or corroded during the use of the device.
The materials of the substrate 1000 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 1000.
The material of the intermediate layer 1001 includes: a polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 1001 is silicon dioxide.
The material of the piezoelectric layer 1004 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 1004 is made of lithium niobate.
In this embodiment, the electrode structure 1005 includes: the first bus 10051 and the second bus 10052 are arranged in parallel along a first direction X, the first bus 10051 is connected to a plurality of first electrode strips 10053 arranged in parallel along a second direction Y, the second bus 10052 is connected to a plurality of second electrode strips 10054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 10053 and the second electrode strips 10054 are arranged in a staggered manner.
In this embodiment, the widths of the first electrode stripes 10053 and the second electrode stripes 10054 are equal; the first electrode bar 10053 and the second electrode bar 10054 have a first width dimension d1, the central axis of the first electrode bar 10053 and the central axis of the second electrode bar 10054 adjacent to each other have a first central dimension d2, and the ratio of the first central dimension d2 to the first width dimension d1 ranges from: 1.2 to 20.
In this embodiment, the thickness of the first electrode bar 10053 and the second electrode bar 10054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 1005 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 1005 is one or more layers. In this embodiment, the electrode structure 1005 has two layers, and the material of the electrode structure 1005 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the fm layer 1006 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the fm layer 1006 is silicon nitride.
In this embodiment, by increasing or decreasing the depth of the groove 1007, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 1006 can control the device frequency more flexibly and accurately.
The groove 1007 is in the shape of any polygon. In this embodiment, the groove 1007 is rectangular.
The material of the temperature compensation layer 1008 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 1008 is silicon dioxide.
In this embodiment, since the temperature compensation layer 1008 and the piezoelectric layer 1004 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device is reduced to 0 ppm/degree centigrade, so as to improve the frequency-temperature stability of the resonant device.
Fig. 101 to 112 are schematic structural diagrams of steps of a method for forming a bulk acoustic wave resonator according to still another embodiment of the present invention.
Referring to fig. 101, a sacrificial substrate 1103 is provided.
The material of the sacrificial substrate 1103 includes: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the sacrificial substrate 1103.
Referring to fig. 102, a piezoelectric layer 1104 is formed on the sacrificial substrate 1103.
The material of the piezoelectric layer 1104 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 1104 is made of lithium niobate.
Referring to fig. 103 and 104, fig. 104 is a schematic view of a cross section taken along the O-O line in fig. 103, wherein an electrode structure 1105 is formed on the piezoelectric layer 1104.
In this embodiment, the electrode structure 1105 includes: the first bus 11051 and the second bus 11052 are arranged in parallel along a first direction X, the first bus 11051 is connected with a plurality of first electrode strips 11053 arranged in parallel along a second direction Y, the second bus 11052 is connected with a plurality of second electrode strips 11054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 11053 and the second electrode strips 11054 are arranged in a staggered manner.
In this embodiment, the widths of the first electrode stripes 11053 and the second electrode stripes 11054 are equal; the first electrode stripes 11053 and the second electrode stripes 11054 have a first width dimension d1, the central axes of the adjacent first electrode stripes 11053 and the central axes of the adjacent second electrode stripes 11054 have a first central dimension d2, and the ratio range of the first central dimension d2 to the first width dimension d1 is: 1.2 to 20.
In the present embodiment, the thickness of the first electrode stripes 11053 and the second electrode stripes 11054 is equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The material of the electrode structure 1105 includes: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 1105 is one or more layers. In this embodiment, the electrode structure 1105 has two layers, and the material of the electrode structure 1105 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
Referring to fig. 105, the view directions of fig. 105 and fig. 104 are the same, and a temperature compensation layer 1108 is formed on the piezoelectric layer 1104 and at least covers the electrode structure 1105.
The material of the temperature compensation layer 1108 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 1108 is silicon dioxide.
In this embodiment, since the temperature compensation layer 1108 and the piezoelectric layer 1104 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device frequency is reduced to 0 ppm/degree centigrade, thereby improving the frequency-temperature stability of the resonant device.
In this embodiment, the temperature compensation layer 1108 covers a portion of the piezoelectric layer 1104; in other embodiments, the temperature compensation layer may also completely cover the piezoelectric layer.
Referring to fig. 106, a sacrificial layer 1109 is formed on the piezoelectric layer 1104, wherein the sacrificial layer 1109 covers at least the temperature compensation layer 1108.
The material of the sacrificial layer 1109 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, polyimide is used as the material of the sacrificial layer 1109.
In this embodiment, because the temperature compensation layer 1108 covers a portion of the piezoelectric layer 1104, forming the sacrificial layer 1109 also covers a portion of the piezoelectric layer 1104; in other embodiments, the sacrificial layer is not in contact with the piezoelectric layer when the temperature compensation layer completely covers the piezoelectric layer.
Referring to fig. 107, an intermediate layer 1101 is formed on the piezoelectric layer 1104, the intermediate layer 1101 at least covers the sacrificial layer 1109, the intermediate layer 1101 includes a first side 1101a and a second side 1101b opposite to each other, and the piezoelectric layer 1104 and the sacrificial substrate 1103 are located on the second side 1101b.
The material of the intermediate layer 1101 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 1101 is silicon dioxide.
Referring to fig. 108, a substrate 1100 is provided.
The materials of the substrate 1100 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 1100.
Referring to fig. 109, the substrate 1100 and the intermediate layer 1101 are bonded, the substrate 1100 being located on the first side 1101a; after bonding the substrate 1100 and the intermediate layer 1101, the sacrificial substrate 1103 is removed.
The process of removing the sacrificial substrate 1103 includes: a physical grinding process, a wet etching process or a dry etching process.
In this embodiment, the process of removing the sacrificial substrate 1103 adopts a physical grinding process.
In this embodiment, a bonding process is used to join the substrate 1100 and the intermediate layer 1101; in other embodiments, bonding the substrate and the intermediate layer may also employ an adhesive process.
Referring to fig. 110 and 111, fig. 111 is a schematic cross-sectional view taken along a line P-P in fig. 110, a frequency modulation layer 1106 is formed, and is located on the second side 1101b and on the piezoelectric layer 1104, the middle layer 1101 and the frequency modulation layer 1106 are respectively located on two sides of the piezoelectric layer 1104, and the electrode structure 1105 and the frequency modulation layer 1106 are respectively located on two sides of the piezoelectric layer 1104.
The material of the tuning layer 1106 comprises a metal or an insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the frequency modulation layer 1106 is silicon nitride.
In this embodiment, the frequency modulation region S of the frequency modulation layer 1106 includes a plurality of grooves 1107, and a projection of the electrode structure 1105 on the substrate 1100 is located within a projection range of the frequency modulation region S on the substrate 1100. By increasing or decreasing the depth of the recess 1107, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 1106 can control the device frequency more flexibly and accurately.
In this embodiment, a plurality of the grooves 1107 are uniformly distributed in the frequency modulation region.
The distribution of the plurality of grooves 1107 can be any polygon or ring, and a single groove 1107 has any polygon or circle. In this embodiment, a plurality of the grooves 1107 are distributed in a rectangular shape, and a single groove 1107 is also in a rectangular shape.
Referring to fig. 112, after the frequency modulation layer 1106 is formed, the sacrificial layer 1109 is removed, a cavity 1102 is formed in the middle layer 1101, an opening of the cavity 1102 is located on the second side 1101b, and the electrode structure 1105 is located in the cavity 1102.
In this embodiment, since the electrode structure 1105 is located in the cavity 1102, the piezoelectric layer 1104 can provide a relatively flat surface for the formed frequency modulation layer 1106, so as to reduce lattice defects of the thin film of the frequency modulation layer 1106, and improve the quality of the thin film, thereby enabling the frequency modulation layer 1106 to control the frequency of the device more flexibly and accurately. In addition, since the electrode structure 1105 is located in the cavity 1102, the electrode structure 1105 can be effectively prevented from being oxidized or corroded during the use of the device.
In this embodiment, after the sacrificial layer 1109 is removed, the temperature compensation layer 1108 is located within the cavity 1102 and the piezoelectric layer 1104 is located on the temperature compensation layer 1108.
In this embodiment, the process of removing the sacrificial layer 1106 is a wet etching process.
Accordingly, the embodiment of the present invention further provides a bulk acoustic wave resonator device, please refer to fig. 112, which includes: a substrate 1100; an intermediate layer 1101, the intermediate layer 1101 comprising a first side 1101a and a second side 1101b opposite, the substrate 1100 being located on the first side 1101a, the intermediate layer 1101 comprising a cavity 1102, an opening of the cavity 1102 being located on the second side 1101b; an electrode structure 1105 located within said cavity 1102; a piezoelectric layer 1104 positioned on said second side 1101b and on said electrode structure 1105, said piezoelectric layer 1104 covering at least said cavity 1102; a temperature compensation layer 1108 located within the cavity 1102 and covering at least the electrode structure 1105, the piezoelectric layer 1104 being located on the temperature compensation layer 1108; a frequency modulation layer 1106 located on the second side 1101b and on the piezoelectric layer 1104, wherein the middle layer 1101 and the frequency modulation layer 1106 are respectively located on two sides of the piezoelectric layer 1104, the electrode structure 1105 and the frequency modulation layer 1106 are respectively located on two sides of the piezoelectric layer 1104, a frequency modulation region S of the frequency modulation layer 1106 includes a plurality of grooves 1107, and a projection of the electrode structure 1105 on the substrate 1100 is located in a projection range of the frequency modulation region S on the substrate 1100.
In this embodiment, because the electrode structure 1105 is located in the cavity 1102, the piezoelectric layer 1104 can provide a relatively flat surface for the formed frequency modulation layer 1106, so as to reduce lattice defects of the thin film of the frequency modulation layer 1106, improve the quality of the thin film, and further enable the frequency modulation layer 1106 to control the frequency of the device more flexibly and accurately. In addition, because the electrode structure 1105 is located in the cavity 1102, the electrode structure 1105 can be effectively prevented from being oxidized or corroded during the use of the device.
The materials of the substrate 1100 include: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics or polymers; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide.
In this embodiment, silicon is used as the material of the substrate 1100.
The material of the intermediate layer 1101 includes: polymer, insulating dielectric, or polysilicon; the polymer comprises: benzocyclobutene (i.e., BCB), photosensitive epoxy photoresist (e.g., SU-8), polyimide; the insulating dielectric includes: aluminum nitride, silicon dioxide, silicon nitride, or titanium oxide.
In this embodiment, the material of the intermediate layer 1101 is silicon dioxide.
The material of the piezoelectric layer 1104 includes: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, or lead magnesium niobate-lead titanate.
In this embodiment, the piezoelectric layer 1104 is made of lithium niobate.
In this embodiment, the electrode structure 1105 includes: the first bus 11051 and the second bus 11052 are arranged in parallel along a first direction X, the first bus 11051 is connected with a plurality of first electrode strips 11053 arranged in parallel along a second direction Y, the second bus 11052 is connected with a plurality of second electrode strips 11054 arranged in parallel along the second direction Y, the first direction X is perpendicular to the second direction Y, and the first electrode strips 511053 and the second electrode strips 11054 are arranged in a staggered manner.
In this embodiment, the first electrode stripes 11053 and the second electrode stripes 11054 have the same width; the first electrode stripes 11053 and the second electrode stripes 11054 have a first width dimension d1, the central axes of the adjacent first electrode stripes 1153 and the central axes of the adjacent second electrode stripes 11054 have a first central dimension d2, and the ratio range of the first central dimension d2 to the first width dimension d1 is: 1.2 to 20 parts by weight.
In this embodiment, the thicknesses of the first electrode stripes 11053 and the second electrode stripes 11054 are equal to the first width dimension d1; in other embodiments, the thickness of the first electrode stripes and the second electrode stripes may not be equal to the first width dimension.
The materials of the electrode structure 1105 include: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
The electrode structure 1105 is one or more layers. In this embodiment, the electrode structure 1105 has two layers, and the material of the electrode structure 1105 is molybdenum aluminum, tungsten aluminum, or platinum aluminum.
The material of the fm layer 1106 includes metal or insulating dielectric; wherein the metals include: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
In this embodiment, the material of the fm layer 1106 is silicon nitride.
In this embodiment, by increasing or decreasing the depth of the groove 1107, the resonant frequency of the resonant device can be adjusted, so that the frequency modulation layer 1106 can control the frequency of the device more flexibly and accurately.
In this embodiment, a plurality of the grooves 1107 are uniformly distributed in the frequency modulation region S.
The distribution of the plurality of grooves 1107 can be any polygon or ring, and a single groove 1107 has any polygon or circle. In this embodiment, a plurality of the grooves 1107 are distributed in a rectangular shape, and a single groove 1107 is also rectangular.
The material of the temperature compensation layer 1108 includes: silicon dioxide, silicon oxycarbide, or silicon oxyfluoride. In this embodiment, the material of the temperature compensation layer 1108 is silicon dioxide.
In this embodiment, since the temperature compensation layer 1108 and the piezoelectric layer 1104 have opposite temperature frequency shift characteristics, the temperature coefficient of the resonant device is decreased to 0 ppm/degree centigrade, so as to improve the frequency-temperature stability of the resonant device.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (20)
1. A bulk acoustic wave resonator device, comprising:
a substrate;
an intermediate layer comprising opposing first and second sides, the substrate being located on the first side, the intermediate layer comprising a cavity, an opening of the cavity being located on the second side;
an electrode structure located within the cavity;
a piezoelectric layer on the second side and on the electrode structure, the piezoelectric layer covering at least the cavity;
the frequency modulation layer is located the second side and is located the piezoelectric layer top, the projection of electrode structure is in on the base the frequency modulation layer is in the projection range on the base, the intermediate level with the frequency modulation layer is located respectively the both sides of piezoelectric layer, the electrode structure with the frequency modulation layer is located respectively the both sides of piezoelectric layer.
2. The bulk acoustic wave resonator device according to claim 1, wherein the frequency-modulated layer comprises a recess, and a projection of the electrode structure onto the substrate is located within a projection of the recess onto the substrate.
3. The bulk acoustic wave resonator device of claim 1, wherein the frequency-modulated region of the frequency-modulated layer comprises a plurality of grooves, and a projection of the electrode structure onto the substrate is located within a projection of the frequency-modulated region onto the substrate.
4. The bulk acoustic wave resonator device according to claim 3, wherein a plurality of the grooves are uniformly distributed in the frequency modulation region.
5. The bulk acoustic wave resonator device according to claim 1, 2, or 3, further comprising: and the temperature compensation layer is positioned on the second side and on the piezoelectric layer, and the piezoelectric layer and the frequency modulation layer are respectively positioned on two sides of the temperature compensation layer.
6. The bulk acoustic wave resonator device according to claim 1, 2, or 3, further comprising: and the temperature compensation layer is positioned in the cavity and at least covers the electrode structure, and the piezoelectric layer is positioned on the temperature compensation layer.
7. The bulk acoustic wave resonator device of claim 1, wherein the electrode structure comprises: the first bus and the second bus are arranged in parallel along a first direction, the first bus is connected with a plurality of first electrode strips which are arranged in parallel along a second direction, the second bus is connected with a plurality of second electrode strips which are arranged in parallel along the second direction, the first direction is perpendicular to the second direction, and the first electrode strips and the second electrode strips are arranged in a staggered mode.
8. The bulk acoustic wave resonator device according to claim 7, wherein the first electrode strips and the second electrode strips are equal in width; the first electrode strips and the second electrode strips have a first width dimension, the central axes of the first electrode strips and the second electrode strips adjacent to each other have a first central dimension, and the ratio of the first central dimension to the first width dimension ranges from: 1.2 to 20.
9. The bulk acoustic wave resonator device of claim 1, wherein the substrate material comprises: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, aluminum oxide, magnesium oxide, ceramics, or polymers.
10. The bulk acoustic wave resonator device according to claim 1, wherein the material of the intermediate layer comprises: polymer, insulating dielectric, or polysilicon.
11. The bulk acoustic wave resonator device of claim 1, wherein the material of the electrode structure comprises: one or more of molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, and titanium.
12. The bulk acoustic wave resonator device of claim 1, wherein the material of the frequency tuning layer comprises a metal or an insulating dielectric; wherein the metal comprises: molybdenum, ruthenium, tungsten, platinum, iridium, magnesium, aluminum, beryllium, copper, gold, chromium, cobalt, or titanium; the insulating dielectric includes: silicon nitride, silicon oxide, aluminum oxide, silicon carbide, silicon oxycarbide, aluminum nitride, gallium arsenide, or gallium nitride.
13. A method of forming a bulk acoustic wave resonator device, comprising:
providing a sacrificial substrate;
forming a piezoelectric layer on the sacrificial substrate;
forming an electrode structure on the piezoelectric layer;
forming a sacrificial layer on the piezoelectric layer, the sacrificial layer covering at least the electrode structure;
forming an intermediate layer on the piezoelectric layer, the intermediate layer covering at least the sacrificial layer, the intermediate layer including opposing first and second sides, the piezoelectric layer and the sacrificial substrate being located on the second side;
providing a substrate;
bonding the substrate and the intermediate layer, the substrate being on the first side;
removing the sacrificial substrate after bonding the substrate and the intermediate layer;
after the sacrificial substrate is removed, forming a frequency modulation layer located on the second side, wherein the projection of the electrode structure on the substrate is located in the projection range of the frequency modulation layer on the substrate, the middle layer and the frequency modulation layer are respectively located on two sides of the piezoelectric layer, and the electrode structure and the frequency modulation layer are respectively located on two sides of the piezoelectric layer;
after the frequency modulation layer is formed, the sacrificial layer is removed, a cavity is formed and embedded in the middle layer, the opening of the cavity is located on the second side, and the electrode structure is located in the cavity.
14. The method of forming a bulk acoustic wave resonator device according to claim 13, wherein the frequency modulation layer includes a recess, and a projection of the electrode structure on the substrate is located within a projection of the recess on the substrate.
15. The method of forming a bulk acoustic wave resonator device according to claim 13, wherein the frequency-modulated region of the frequency-modulated layer includes a plurality of grooves, and a projection of the electrode structure on the substrate is located within a projection range of the frequency-modulated region on the substrate.
16. The method of forming a bulk acoustic wave resonator device according to claim 15, wherein a plurality of the grooves are uniformly distributed in the frequency modulation region.
17. The method of forming a bulk acoustic wave resonator device according to claim 13, 14, or 15, further comprising, before forming the frequency modulation layer: and forming a temperature compensation layer which is positioned on the second side and on the piezoelectric layer, wherein the piezoelectric layer and the frequency modulation layer are respectively positioned on two sides of the temperature compensation layer.
18. The method of forming a bulk acoustic wave resonator device according to claim 13, 14, or 15, further comprising, after forming the electrode structure: forming a temperature compensation layer on the piezoelectric layer and covering at least the electrode structure before forming the sacrificial layer; the sacrificial layer covers the temperature compensation layer; and after removing the sacrificial layer, the temperature compensation layer is located in the cavity.
19. The method of forming a bulk acoustic wave resonator device according to claim 13, wherein the electrode structure comprises: the first bus and the second bus are arranged in parallel along a first direction, the first bus is connected with a plurality of first electrode strips which are arranged in parallel along a second direction, the second bus is connected with a plurality of second electrode strips which are arranged in parallel along the second direction, the first direction is vertical to the second direction, and the first electrode strips and the second electrode strips are arranged in a staggered mode.
20. The method of forming a bulk acoustic wave resonator device according to claim 19, wherein the first electrode stripes and the second electrode stripes have equal widths; the first electrode strips and the second electrode strips have a first width dimension, the central axes of the adjacent first electrode strips and the central axes of the adjacent second electrode strips have a first central dimension, and the ratio of the first central dimension to the first width dimension ranges from: 1.2 to 20.
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| CN202211134351.2A CN115242215B (en) | 2022-09-19 | 2022-09-19 | Bulk acoustic wave resonator device and method of forming the same |
| PCT/CN2023/118474 WO2024061071A1 (en) | 2022-09-19 | 2023-09-13 | Bulk acoustic wave resonance apparatus and method for forming same |
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| CN202211134351.2A CN115242215B (en) | 2022-09-19 | 2022-09-19 | Bulk acoustic wave resonator device and method of forming the same |
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| US20210111699A1 (en) * | 2019-10-15 | 2021-04-15 | Global Communication Semiconductors, Llc | Bulk Acoustic Wave Resonator with Multilayer Base |
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| CN113872554A (en) * | 2021-09-08 | 2021-12-31 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator, filter, and radio frequency front end device |
| CN113810007B (en) * | 2021-09-08 | 2023-08-29 | 常州承芯半导体有限公司 | Surface acoustic wave resonator, filter, and radio frequency front-end device |
| CN114337581A (en) * | 2022-03-17 | 2022-04-12 | 常州承芯半导体有限公司 | Method for forming bulk acoustic wave resonator |
| CN114362712B (en) * | 2022-03-21 | 2022-10-21 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method of forming the same |
| CN115242215B (en) * | 2022-09-19 | 2023-02-21 | 常州承芯半导体有限公司 | Bulk acoustic wave resonator device and method of forming the same |
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| WO2024061071A1 (en) | 2024-03-28 |
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