CN113972901A - Filter and preparation method thereof - Google Patents
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- CN113972901A CN113972901A CN202010724130.5A CN202010724130A CN113972901A CN 113972901 A CN113972901 A CN 113972901A CN 202010724130 A CN202010724130 A CN 202010724130A CN 113972901 A CN113972901 A CN 113972901A
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 239000004020 conductor Substances 0.000 claims description 8
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 8
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 239000011733 molybdenum Substances 0.000 claims description 5
- 239000010409 thin film Substances 0.000 claims description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- 239000010937 tungsten Substances 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 4
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The embodiment of the application provides a filter, which comprises at least two resonators, wherein each resonator comprises a top electrode, a piezoelectric layer and a bottom electrode; the resonators are longitudinally stacked, the acoustic reflection layers are arranged between the adjacent resonators, electrodes of the resonators extend to the surface of the filter, the at least two resonators are connected through a circuit, the circuit is arranged on the surface of the filter, and the surface is the plane where the acoustic reflection layers are located; the application also provides a preparation method of the filter, which comprises the steps of preparing the substrate, sequentially preparing the first resonator, the supporting layer, the acoustic reflection layer and the second resonator, extending the electrode of the first resonator to the surface of the acoustic reflection layer, and connecting the first resonator and the second resonator through a circuit. The longitudinally integrated filter provided in the embodiment of the application reduces the size of the filter, improves the integration of the filter, simplifies the structure of the resonator and reduces the production cost of the filter.
Description
Technical Field
The embodiment of the invention relates to the field of filters, in particular to a filter and a preparation method thereof.
Background
The radio frequency filter is used as a necessary high-frequency component of a radio frequency part of the wireless terminal, and at least two groups of resonators working at different resonant frequencies are required for manufacturing the filter. The current 4G/LTE mobile phone and 5G mobile phone products need to support multiple frequency bands for communication at the same time, and meanwhile, need to realize smaller and integrated communication system structures. In this case, in order to implement communication in multiple frequency bands, more filters need to be added in the space of the original rf front-end circuit, which puts new requirements on the size and integration of the filters themselves.
In the prior art, an SMR-BAW resonator (solid-resonator-bulk-acoustic-wave) has high electromechanical coupling coefficient, mechanical quality factor and high operating frequency, and thus is one of the mainstream rf resonators at present. In the existing filter, a plurality of resonators are interconnected in the same plane through expansion and integration in the transverse dimension to form the filter, and the size of the formed filter is larger. In addition, for a plurality of resonators, for example, SMR-BAW resonators are used, since the thicknesses of the piezoelectric thin films of SMR-BAW devices on the wafer of each resonator are the same, it is common to adjust the resonance frequency of each resonator by applying loads of different magnitudes to the respective resonators to obtain different resonance frequencies, which makes the manufacturing processes of the plurality of resonators complicated and restricts miniaturization of the rf filter.
Disclosure of Invention
The embodiment of the invention provides an optimized filter to reduce the size of the filter.
In a first aspect, an embodiment of the present application provides a filter, including at least two resonators, each resonator including a top electrode, a piezoelectric layer, and a bottom electrode; the at least two resonators are longitudinally stacked, an acoustic reflection layer is arranged between two adjacent resonators of the at least two resonators, the at least two resonators include a first resonator and a second resonator which are adjacently arranged,
the first resonator is positioned at the top of the filter, the second resonator is positioned below the first resonator, and a top electrode and a bottom electrode of the second resonator respectively extend to the surface of the acoustic reflection layer below the first resonator;
or the second resonator is positioned at the top of the filter, the first resonator is positioned below the second resonator, and the top electrode and the bottom electrode of the first resonator respectively extend to the surface of the acoustic reflection layer below the second resonator.
In the embodiment, the resonators are longitudinally integrated, and two adjacent filters share the same sound reflection structure, so that the space size of the filter is saved, a plurality of resonators can be prepared on the same wafer, the size of the filter is reduced, and the integration of the filter is improved.
With reference to the first aspect, in one possible implementation manner, the first resonator and the second resonator have different resonance frequencies.
With reference to the first aspect, in one possible implementation manner, the first resonator and the second resonator having different resonant frequencies include: the thickness of the piezoelectric layer of the first resonator and the thickness of the piezoelectric layer of the second resonator are different.
In the above embodiment, the piezoelectric thin films and electrodes with different thicknesses and materials can be manufactured on the same wafer, and the frequency of the resonator can be adjusted by applying a pressure load, so that the resonator with different resonant frequencies can be manufactured, and the size and manufacturing cost of the filter can be reduced.
With reference to the first aspect, in one possible implementation manner, the acoustic reflection layer is a bragg reflection structure, and the acoustic reflection layer includes a low acoustic impedance material and a high acoustic impedance material that are stacked and arranged alternately in a thickness direction.
With reference to the first aspect, in one possible implementation, the acoustic reflection layer is a photonic crystal structure including low acoustic impedance materials and high acoustic impedance materials arranged in a plurality of directions.
In the above embodiment, the low acoustic impedance material and the high acoustic impedance material arranged in multiple directions are adopted, so that the mechanical stability is high, and the heat dissipation performance is good.
With reference to the first aspect, in one possible implementation manner, the filter is a Ladder-type filter, the top electrode of the first resonator and the top electrode of the second resonator are both electrically connected to the first output terminal of the filter, the bottom electrode of the first resonator is grounded, and the bottom electrode of the second resonator is electrically connected to the first input terminal of the filter.
In the above embodiments, the Ladder type filter can be used for single-ended (single-ended/unbalanced) and differential (balanced) signals for the unattenuated transmission of band signals in the passband, and for the maximum attenuation of out-of-band signals.
With reference to the first aspect, in one possible implementation manner, the filter is a multi-order Ladder type filter including at least two Ladder type filters, the at least two Ladder type filters are connected in series, the first-order Ladder type filter is connected to the first input terminal, and the last-order Ladder type filter is connected to the first output terminal.
With reference to the first aspect, in one possible implementation, the at least two Ladder-type filters are disposed on the same plane.
With reference to the first aspect, in one possible implementation manner, the at least two Ladder-type filters are longitudinally stacked, wherein an acoustic reflection layer is disposed between two adjacent Ladder-type filters.
In the above embodiment, the multi-order Ladder type filter includes at least two Ladder type filters, and the filter with a complex structure can be manufactured by adopting a longitudinally integrated structure, so that the integration of the complex filter is improved, and the application range of the filter adopting the longitudinally integrated structure is expanded.
With reference to the first aspect, in a possible implementation manner, the filter is a Lattice-type filter, and includes a first resonator, a second resonator, a third resonator, and a fourth resonator, where the third resonator and the fourth resonator are longitudinally stacked and have an acoustic reflection layer disposed therebetween, a top electrode of the first resonator is electrically connected to a top electrode of the second resonator and then connected to a first input end of the filter, a bottom electrode of the third resonator is electrically connected to a bottom electrode of the fourth resonator and then connected to a second input end of the filter, a bottom electrode of the first resonator is electrically connected to a top electrode of the fourth resonator and then connected to a first output end of the filter, and a bottom electrode of the second resonator is electrically connected to a top electrode of the third resonator and then connected to a second output end of the filter.
With reference to the first aspect, in one possible implementation manner, the third resonator is longitudinally stacked and disposed above a fourth resonator, a top electrode and a bottom electrode of the fourth resonator respectively extend to a surface of an acoustic reflection layer below the third resonator, the third resonator is disposed on the same plane as the first resonator, and the fourth resonator is disposed on the same plane as the second resonator;
or the third resonator is longitudinally stacked above a fourth resonator, a top electrode and a bottom electrode of the fourth resonator respectively extend to the surface of the acoustic reflection layer below the third resonator, the third resonator and the second resonator are arranged on the same plane, and the fourth resonator and the first resonator are arranged on the same plane;
or the fourth resonator is longitudinally stacked above a third resonator, a top electrode and a bottom electrode of the third resonator respectively extend to the surface of the acoustic reflection layer below the fourth resonator, the third resonator and the first resonator are arranged on the same plane, and the fourth resonator and the second resonator are arranged on the same plane;
or the fourth resonator is longitudinally stacked above the third resonator, a top electrode and a bottom electrode of the third resonator respectively extend to the surface of the acoustic reflection layer below the fourth resonator, the third resonator and the second resonator are arranged on the same plane, and the fourth resonator and the first resonator are arranged on the same plane.
With reference to the first aspect, in one possible implementation manner, the first resonator, the second resonator, the third resonator, and the fourth resonator are longitudinally stacked, and an acoustic reflection layer is disposed between adjacent resonators.
In the above embodiment, the plurality of resonators are longitudinally integrated, and two adjacent filters share the same acoustic reflection structure, so that piezoelectric films and electrodes with different thicknesses and materials can be manufactured on the same wafer, and the filters with different resonant frequencies can be designed and manufactured, thereby reducing the size and manufacturing cost of the filters. .
With reference to the first aspect, in a possible implementation manner, the filter is a multi-order Lattice type filter including at least two Lattice type filters, the at least two Lattice type filters are connected in series, the first-order Lattice type filter is electrically connected to the first input terminal and the second input terminal, and the last-order Lattice type filter is electrically connected to the first output terminal and the second output terminal.
With reference to the first aspect, in one possible implementation manner, the at least two Lattice-type filters are disposed on the same plane.
With reference to the first aspect, in one possible implementation manner, the at least two Lattice-type filters are longitudinally stacked, and an acoustic reflection layer is disposed between two adjacent Lattice-type filters.
In the above embodiment, the multi-order Lattice type filter includes at least two Lattice type filters, and the filter with a complex structure can be manufactured by adopting a longitudinally integrated structure, so that the integration of the complex filter is improved, and the application range of the filter adopting the longitudinally integrated structure is expanded.
In a second aspect, embodiments of the present application further provide a method for manufacturing a filter in any one of the first aspect, where the method includes the following steps:
preparing a substrate, wherein the substrate is provided with a cavity;
growing a sacrificial layer in a cavity of a substrate such that the cavity is filled with the sacrificial layer;
sequentially preparing a first bottom electrode, a first piezoelectric layer and a first top electrode of a first resonator on the upper surface of the substrate filled with the sacrificial layer, wherein at least one part of the first bottom electrode, at least one part of the first piezoelectric layer and at least one part of the first top electrode are all arranged above the sacrificial layer;
growing a supporting layer on the upper surface of the first top electrode, and grinding the supporting layer to enable the upper surface of the supporting layer and the upper surface of the first top electrode to be positioned on the same plane;
preparing an acoustic reflection layer on an upper surface of the first top electrode and an upper surface of the support layer;
sequentially preparing a second bottom electrode, a second piezoelectric layer and a second top electrode of a second resonator on the upper surface of the acoustic reflection layer;
sequentially etching the first resonator, the acoustic reflection layer and the second resonator, preparing at least one first release hole communicated with the sacrificial layer, and releasing the sacrificial layer through the at least one first release hole to form a cavity structure;
sequentially etching the sound reflection structure and the supporting layer, preparing a second release hole connected with the first bottom electrode, and filling a conductive material in the second release hole;
sequentially etching the sound reflection structure and the supporting layer, preparing a third release hole connected with the first top electrode, and filling a conductive material in the third release hole; the first resonator and the second resonator are electrically connected by a circuit on the surface of the acoustic reflection layer.
With reference to the second aspect, in a possible implementation manner, the acoustic reflection layer is a bragg reflection structure, and thin film materials with high and low acoustic impedances alternately in the thickness direction are sequentially deposited by a magnetron sputtering method; or the acoustic reflection layer is of a phononic crystal structure, and high and low acoustic impedance materials which are periodically distributed along a plurality of directions are deposited by adopting a magnetron sputtering method.
With reference to the second aspect, in one possible embodiment, the support layer is Si or SiC, the low acoustic impedance material is silicon dioxide, and the high acoustic impedance material is aluminum nitride, tungsten, or molybdenum.
In the above embodiments, the material used for the supporting layer can reduce the energy loss and improve the performance of the resonator.
In a second aspect, embodiments of the present application further provide a preparation method for preparing the above filter, including: preparing a substrate, wherein the substrate is provided with a cavity; growing a sacrificial layer in the cavity of the substrate; preparing a first bottom electrode, a first piezoelectric layer and a first top electrode of a first resonator in sequence; growing a supporting layer on the surface of the first top electrode, and mechanically grinding and flattening the supporting layer to the first top electrode; preparing an acoustic reflection layer on the surface of the first top electrode supporting layer; preparing a second bottom electrode, a second piezoelectric layer and a second top electrode of a second resonator in sequence; sequentially etching the first resonator, the acoustic reflection layer and the second resonator, preparing a first release hole connected with the sacrificial layer, and releasing the sacrificial layer to form a cavity structure; sequentially etching the acoustic reflection structure and the support layer, preparing a second release hole connected with the first bottom electrode, and extending the first bottom electrode and the first top electrode to the surface of the acoustic reflection layer; the first resonator and the second resonator are electrically connected to each other on the surface of the acoustic reflection layer.
According to the technical scheme, at least two resonators are longitudinally stacked, and the longitudinally integrated resonators can be finally manufactured into the filter through circuit connection. Two adjacent filters share the same sound reflection structure, so that the space size of the filters is saved. The longitudinally integrated filter can be used for preparing a plurality of resonators on the same wafer element, and can also be used for designing resonators with different resonant frequencies in the same wafer element, so that the size (such as the transverse size or the transverse area) of the filter is reduced, the integration of the filter is improved, the structures of the resonators are simplified, and the yield and the production cost are improved.
Drawings
While the drawings associated with the various embodiments of the subject application will be described, it should be apparent that the drawings in the following description are illustrative of some embodiments of the invention and that other drawings may be derived by those skilled in the art without the benefit of inventive faculty.
Fig. 1 is a schematic structural diagram of a filter according to an embodiment of the present application;
FIG. 2 is a top view of the filter of FIG. 1;
FIG. 3 is a schematic diagram of the circuit structure of the filter shown in FIG. 1;
FIG. 4 is a circuit schematic of the filter of FIG. 1;
fig. 5 is a schematic structural diagram of a filter including a first acoustic reflection layer according to an embodiment of the present application;
FIG. 6 is a cross-sectional view of the first acoustic reflective layer of the filter of FIG. 5 taken along plane A-A;
fig. 7-1 is a schematic circuit diagram of a filter according to an embodiment of the present application;
fig. 7-2 is a schematic circuit diagram of a filter according to an embodiment of the present application;
fig. 7-3 are schematic circuit diagrams of circuit structures of a filter according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of a filter according to an embodiment of the present application;
FIG. 9 is a top view of the filter of FIG. 8;
fig. 10 is a schematic structural diagram of a filter according to an embodiment of the present application;
FIG. 11 is a schematic diagram of the circuit configuration of the filter shown in FIG. 8;
FIG. 12 is a schematic diagram of the circuit configuration of the filter shown in FIG. 10;
FIG. 13 is a schematic circuit diagram of the filter of FIGS. 8 and 10;
fig. 14-1 is a schematic circuit diagram of a filter according to an embodiment of the present application;
fig. 14-2 is a schematic circuit diagram of a filter according to an embodiment of the present application;
fig. 15-1 to 15-12 are schematic diagrams illustrating steps of a method for manufacturing a filter according to an embodiment of the present disclosure.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic structural diagram of a filter according to an embodiment of the present application. The first filter 301 includes a first resonator 210, a second resonator 220, a substrate 100, a first support layer 103, and a first acoustic reflection layer 104. The first acoustic reflection layer 104 is disposed between the first resonator 210 and the second resonator 220, and the second resonator 220 and the first resonator 210 share the first acoustic reflection layer 104. Second resonator 220 is disposed adjacent to first resonator 210, which may mean that an acoustic reflective layer is disposed between the second resonator and first resonator 210, and it is not required that the second resonator be in close proximity to the first resonator. The second resonator 220 is disposed above the first resonator 210, the first resonator 210 and the second resonator 220 are stacked above the substrate 100, the first supporting layer 103 is disposed above the first resonator 210 for supporting the first acoustic reflection layer 104, and the top electrode 213 and the bottom electrode 211 of the first resonator 210 extend to the surface of the first acoustic reflection layer 104 below the second resonator 220, respectively. The first resonator 210, the second resonator 220 and the first acoustic reflection layer 104 are provided with at least one first release hole 130, the first release hole 130 is communicated with the cavity of the substrate 100, and a cavity structure is formed by releasing the sacrificial layer through the at least one first release hole 130.
In another embodiment provided in the present application, the first resonator 210 is disposed above the second resonator 220, the first resonator 210 and the second resonator 220 are stacked above the substrate 100, and the top electrode 223 and the bottom electrode 221 of the second resonator 220 respectively extend to the surface of the first acoustic reflection layer 104 below the first resonator 210.
Below the first resonator 210 is the cavity 102 of the substrate 100, the first resonator 210 comprises a first bottom electrode 211, a first piezoelectric layer 212, and a first top electrode 213, the first bottom electrode 211 and the first top electrode 213 are oppositely disposed, and the first piezoelectric layer 212 is located between the first bottom electrode 211 and the first top electrode 213. The thickness of cavity, electrode and piezoelectric layer can set up according to actual conditions's needs, in the possible implementation that this application embodiment provided, cavity thickness 0.5um ~ 2um, electrode thickness 0.01um ~ 1um, piezoelectric layer thickness 0.1um ~ 3 um.
The second resonator 220 comprises a second bottom electrode 221, a second piezoelectric layer 222, and a second top electrode 223, the second bottom electrode 221 and the second top electrode 223 being disposed opposite to each other, the second piezoelectric layer 222 being located between the second bottom electrode 221 and the second top electrode 223. The thickness of cavity, electrode and piezoelectric layer can set up according to actual conditions's needs, in the possible implementation that this application embodiment provided, cavity thickness 0.5um ~ 2um, electrode thickness 0.01um ~ 1um, piezoelectric layer thickness 0.1um ~ 3 um.
In an embodiment of the present application, the first acoustic reflection layer 104 is a bragg reflection structure, and is made by alternately stacking low acoustic impedance materials 140 and high acoustic impedance materials 141 in the thickness direction. Each layer of the acoustically reflective structure is 1/4 thick at a wavelength at which an acoustic signal having a frequency equal to the center frequency of the filter is transmitted in the layer of material.
Fig. 5 is a schematic structural diagram of a filter including a first acoustic reflection layer according to an embodiment of the present application, as shown in fig. 5 and fig. 6, and fig. 6 is a cross-sectional view of the first acoustic reflection layer 104 of the filter in fig. 5 along a plane a-a. In one embodiment, the first acoustic reflective layer 104 has a photonic crystal structure. Specifically, the phononic crystal structure includes high and low acoustic impedance materials periodically distributed in a plurality of directions, and the low acoustic impedance material 140 is embedded in the high acoustic impedance material 141. The size of the shape of the phononic crystal can be set according to the actual situation, for example, in the present embodiment, the shape of the phononic crystal is a rectangular parallelepiped or a column. In this embodiment, adopt multilayer sound reflection structure, the mechanical stability of syntonizer is strong, and heat dispersion is good.
Fig. 2 is a top view of an embodiment of the filter shown in fig. 1. In this example, the circuit connection plane of the first resonator 210 and the second resonator 220 is the surface of the first acoustic reflection layer 104. The first output terminal 2, the first input terminal 1 and the ground terminal 3 are disposed on the surface of the first acoustic reflection layer 104, and the top and bottom electrodes of the second resonator 220 are disposed on the surface of the first acoustic reflection layer 104; as shown in fig. 15-11 and 15-12, the first bottom electrode 211 and the first top electrode 213 of the first resonator 210 are drawn out to the surface of the first acoustic reflection layer through the second release hole 131, and the second release hole 131 penetrates the first acoustic reflection layer 104 and the first support layer 104.
Fig. 3 is a schematic circuit diagram of a Ladder filter, as shown in fig. 3 and 4, and fig. 4 is a schematic circuit diagram of a Ladder filter. In an embodiment of the present application, the filter is a Ladder-type filter, and the Ladder-type filter 301 is formed by connecting the first resonator 210 and the second resonator 220 through a circuit. The first top electrode 213 of the first resonator 210 is connected to the second top electrode 223 of the second resonator 220 via the first circuit 11. The first top electrode 213 is connected to the first output terminal 2, the first bottom electrode 211 is connected to the ground, and the second bottom electrode 221 is connected to the first input terminal 1. In another embodiment provided by the present application, the second top electrode 223, or the first circuit 11, is connected to the first output terminal 2.
In the Ladder type filter 301 of the present embodiment, the resonant frequency of the first resonator and the resonant frequency of the second resonator may be the same frequency or different frequencies. Since the resonance frequency is directly inversely proportional to the thickness of the piezoelectric film, the thicknesses of the piezoelectric film and the electrodes of the resonators are different for different frequencies. In an embodiment provided by the application, the resonators are longitudinally integrated, and the thickness of the resonators does not need to be limited in the longitudinal direction, so that piezoelectric films and electrodes with different thicknesses and materials can be manufactured on the same wafer, the manufacturing process can be designed to be the resonators with different resonant frequencies, and the size and the manufacturing process cost of the filter are reduced.
In an embodiment of the present invention, the filter is a multiple-order Ladder type filter, and a plurality of Ladder type filters 301 with the same structure may constitute the multiple-order Ladder type filter, wherein each-order Ladder type filter 301 includes a first resonator 210 and a second resonator 220, and the plurality of Ladder type filters 301 are connected in series, that is, an output terminal of the previous-order Ladder type filter 301 is connected to an input terminal of the next-order Ladder type filter 301.
As shown in fig. 7-1 and 7-2, a schematic circuit structure of a two-stage Ladder type filter according to an embodiment of the present disclosure includes two Ladder type filters 301 with the same structure; for convenience of description of the following circuit structures, two identical Ladder-type filters are respectively referred to as a first-order Ladder-type filter 301 and a second-order Ladder-type filter 301'. An output terminal (for example, the second top electrode 223) of the first-order Ladder type filter 301 is connected to an input terminal of the second-order Ladder type filter 301 ' (for example, the second bottom electrode 221 ') via the second circuit 12, an input terminal (for example, the second bottom electrode 221) of the Ladder type filter 301 is connected to the first input terminal 1, an output terminal (for example, the first top electrode 213 ') of the second-order Ladder type filter 301 ' is connected to the first output terminal 2, and the first bottom electrodes 211 and 103 ' are respectively connected to ground lines.
Fig. 7-1 is a schematic circuit diagram of a two-stage Ladder type filter according to an embodiment of the present application. Specifically, the first Ladder type filter 301 and the second-order Ladder type filter 301 'are disposed on the same plane, and the circuits of the first Ladder type filter 301 and the second-order Ladder type filter 301' are disposed on the surfaces of the first acoustic reflection layer 104 of the first Ladder type filter 301 and the first acoustic reflection layer 104 'of the second-order Ladder type filter 301'.
As shown in fig. 7-2, a schematic circuit structure of a two-stage Ladder type filter according to an embodiment of the present disclosure is shown, wherein a second-stage Ladder type filter 301 'is vertically stacked above the Ladder type filter 301, a second sound reflection layer 401 is disposed between the second-stage Ladder type filter 301' and the Ladder type filter 301, and the second sound reflection layer 401 is a bragg reflection structure or a photonic crystal structure. The second acoustic reflection layer 401 has a similar structure to the first acoustic reflection layer, and is not described in detail here. The circuits of the first and second-order Ladder type filters 301 and 301 ' are disposed on the surface of the first acoustic reflection layer 104 ' of the second-order Ladder type filter 301 ' on the top.
Fig. 8 and 9 are schematic structural diagrams of a filter according to an embodiment of the present application. The filter is a Lattice type filter 302, and the Lattice type filter 302 includes a first resonator 210, a second resonator 220, a third resonator 230, a fourth resonator 240, a substrate 100, a first supporting layer 103, a first acoustic reflection layer 104, a second supporting layer 105, and a third acoustic reflection layer 106. The first acoustic reflection layer 104 is disposed between the second resonator 220 and the first resonator 210, and the second resonator 220 is disposed adjacent to the first resonator 210, which may be a common acoustic reflection layer for the second resonator and the first resonator 210, and does not require that the second resonator be next to the first resonator. The second resonator 220 is disposed above the first resonator 210, the second resonator 220 and the first resonator 210 are stacked above the substrate 100, the first supporting layer 103 is disposed above the first resonator 210 for supporting the first acoustic reflection layer 104, and the top electrode 213 and the bottom electrode 211 of the first resonator 210 extend to the surface of the first acoustic reflection layer 104 below the second resonator 220, respectively. The first resonator 210, the second resonator 220 and the first acoustic reflection layer 104 are provided with at least one first release hole 130, the first release hole 130 is communicated with the cavity of the substrate 100, and a cavity structure is formed by releasing the sacrificial layer through the at least one first release hole 130. The third acoustic reflection layer 106 is disposed between the fourth resonator 240 and the third resonator 230, and the fourth resonator 240 is disposed adjacent to the third resonator 230, which may mean that the fourth resonator 240 and the third resonator 230 are disposed with an acoustic reflection layer, and it is not required that the fourth resonator 240 is next to the third resonator 230. The fourth resonator 240 is disposed above the third resonator 230, the fourth resonator 240 is disposed above the third resonator 230 stacked on the substrate 100, the second support layer 105 is disposed above the third resonator 230 for supporting the third acoustic reflection layer 106, and the top electrode 233 and the bottom electrode 231 of the third resonator 230 respectively extend to the surface of the third acoustic reflection layer 106 below the fourth resonator 240. At least one first release hole 130 is formed in the third resonator 230, the fourth resonator 240 and the third acoustic reflection layer 106, the first release hole 130 communicates with the cavity of the substrate 100, and a cavity structure is formed by releasing the sacrificial layer through the at least one first release hole 130.
A substrate cavity is arranged below the first resonator 210, the first resonator 210 includes a first bottom electrode 211, a first piezoelectric layer 212, and a third top electrode 213, the first bottom electrode 211 and the third top electrode 213 are oppositely disposed, and the first piezoelectric layer 212 is located between the first bottom electrode 211 and the third top electrode 213. The second resonator 220 is disposed above the first acoustic reflection layer 104, the second resonator 220 includes a second bottom electrode 221, a second piezoelectric layer 222, and a second top electrode 223, the second bottom electrode 221 and the second top electrode 223 are disposed opposite to each other, and the second piezoelectric layer 222 is disposed between the second bottom electrode 221 and the second top electrode 223.
A substrate cavity is arranged below the third resonator 230, the third resonator 230 includes a third bottom electrode 231, a third piezoelectric layer 232, and a third top electrode 233, the third bottom electrode 231 and the third top electrode 233 are oppositely disposed, and the third piezoelectric layer 232 is located between the third bottom electrode 231 and the third top electrode 233. The fourth resonator 240 is disposed above the third acoustic reflection layer 106, the fourth resonator 240 includes a fourth bottom electrode 241, a fourth piezoelectric layer 242, and a fourth top electrode 243, the fourth bottom electrode 241 and the fourth top electrode 243 are disposed oppositely, and the fourth piezoelectric layer 242 is disposed between the fourth bottom electrode 241 and the fourth top electrode 243.
The thickness of cavity, electrode and piezoelectric layer can set up according to actual conditions's needs, in the possible implementation mode that this application embodiment provided, cavity thickness 0.5um ~ 2um, electrode thickness 0.01um ~ 1um, piezoelectric layer thickness 0.1um ~ 3 um.
In another embodiment provided in the present application, the first resonator 210 is disposed above the second resonator 220, the first resonator 210 and the second resonator 220 are stacked above the substrate 100, and the top electrode 223 and the bottom electrode 221 of the second resonator 220 respectively extend to the surface of the first acoustic reflection layer 104 below the first resonator 210.
In another embodiment provided in the present application, the third resonator 230 is disposed above the fourth resonator 240, the third resonator 230 and the fourth resonator 240 are stacked above the substrate 100, and the top electrode 243 and the bottom electrode 241 of the fourth resonator 240 respectively extend to the surface of the third acoustic reflection layer 106 below the third resonator 230.
In an embodiment of the present application, the first acoustic reflection layer 104 and the third acoustic reflection layer 106 are bragg reflection structures or photonic crystal structures, and the third acoustic reflection layer 106 has a similar structure to the first acoustic reflection layer 104, and thus, the description thereof is omitted. It should be noted that the first acoustic reflection layer 104 and the third acoustic reflection layer 106 both belong to the filter shown in fig. 9, in the filter, the first acoustic reflection layer 104 and the third acoustic reflection layer 106 may be different regions of the same acoustic reflection layer, and are distinguished by the first and the third for convenience of description and reference. Other similar ways of distinguishing may be similarly understood.
Fig. 9 is a top view of the filter of the embodiment of fig. 8. The circuit connection planes of the first resonator 210, the second resonator 220, the third resonator 230, and the fourth resonator 240 are the surfaces of the first acoustic reflection layer 104 and the third acoustic reflection layer 106. A first input 1, a first output 2, a second input 3, a second output 4 of the filter are arranged on said surface. The first bottom electrode 211, the first top electrode 213, the third bottom electrode 231, the third top electrode 233 are drawn out to the surface through the release holes (the release holes 131, 132 shown in fig. 15-11).
Fig. 10 is a schematic structural diagram of a filter according to an embodiment of the present application. The Lattice type filter 302 includes a first resonator 210, a second resonator 220, a third resonator 230, and a fourth resonator 240, which are sequentially stacked from bottom to top in a longitudinal direction, wherein a fourth acoustic reflection layer 402 is disposed between the second resonator 220 and the third resonator 230, and the fourth acoustic reflection layer 402 is a bragg reflection structure or a photonic crystal structure. The fourth acoustic reflection layer 402 has a similar structure to the first acoustic reflection layer, and is not described herein again. The circuit connection plane of the first resonator 210, the second resonator 220, the third resonator 230, and the fourth resonator 240 is the surface of the third acoustic reflection layer 106 located at the topmost end. The first input terminal 1, the first output terminal 2, the second input terminal 3, and the second output terminal 4 of the filter are disposed on the surface, and the first bottom electrode 211, the third top electrode 213, the third bottom electrode 231, and the third top electrode 233 are drawn out to the surface through the second release hole 131. In one possible embodiment provided by the present application, the vertical positions of the first resonator 210, the second resonator 220, the third resonator 230, and the fourth resonator 240 stacked vertically may be changed according to actual requirements, for example, the fourth resonator 240, the third resonator 230, the second resonator 220, and the first resonator 210 are stacked vertically from top to bottom in sequence.
Fig. 11 is a schematic circuit diagram of the filter shown in fig. 8, fig. 12 is a schematic circuit diagram of the filter shown in fig. 10, and fig. 13 is a schematic circuit diagram of the filters shown in fig. 8 and 10, as shown in fig. 11-13. The first top electrode 213 of the first resonator 210 is connected to the second top electrode 223 of the second resonator 220 through the third circuit 13; the third bottom electrode 231 of the third resonator 230 is connected to the fourth bottom electrode 241 of the fourth resonator 240 via the sixth circuit 16, the first bottom electrode 211 is connected to the second top electrode 223 via the fifth circuit 15, and the second bottom electrode 221 is connected to the third top electrode 233 via the fourth circuit 14. The first top electrode 213 (or the second top electrode 223 or the third circuit 13) is connected to the first input terminal 1, the third top electrode 233 (or the second bottom electrode 221 or the fourth circuit 14) is connected to the first output terminal 2, the third bottom electrode 231 (or the fourth bottom electrode 241 or the sixth circuit 16) is connected to the second input terminal 3, and the second bottom electrode 221 (or the third top electrode 233 or the fourth circuit 14) is connected to the second output terminal 4. The Lattice type filter 302 is formed by electrically connecting the first resonator 210, the second resonator 220, the third resonator 230, and the fourth resonator 240.
In the Lattice type filter 302, an input electrical signal is received by the first input terminal 1 and the second input terminal 3, and when the frequency of the input signal is within the pass band of the filter 302, the input electrical signal is output through the first output terminal 2 and the 7 th output terminal 7. In the Lattice-type filter 302 of the present embodiment, the resonant frequencies of the first resonator 210, the second resonator 220, the third resonator 230, and the fourth resonator 240 may be the same frequency or different frequencies. Since the resonance frequency is directly inversely proportional to the thickness of the piezoelectric film, the thicknesses of the piezoelectric film and the electrodes of the resonators at different resonance frequencies are different. In an embodiment provided by the application, the resonators are longitudinally integrated, and the thickness of the resonators does not need to be limited in the longitudinal direction, so that piezoelectric films and electrodes with different thicknesses and materials can be manufactured on the same wafer, the manufacturing process can be designed to be the resonators with different resonant frequencies, and the size and the manufacturing process cost of the filter are reduced.
An embodiment of the present application provides a filter including a multi-order Lattice type filter, which includes a plurality of Lattice type filters 302, and the plurality of Lattice type filters 302 are connected in series to form the multi-order Lattice type filter. As shown in fig. 14-1 and 14-2, in the embodiment of the present application, the circuit structure of the two-order Lattice type filter 302 is schematically illustrated, and for convenience of the following description, the two Lattice type filters 302 with the same structure are respectively referred to as a first-order Lattice type filter 302 and a second-order Lattice type filter 302'. The multi-order Lattice type filter is connected in a manner that the Lattice type filter 302 is connected in series with the second-order Lattice type filter 302 ', i.e., two output terminals of the Lattice type filter 302 are connected with two input terminals of the second-order Lattice type filter 302'. In one embodiment of the present invention, the fourth circuit 14 (or the output terminal) of the Lattice type filter 301 is connected to the third circuit 13 '(or the input terminal) of the second-order Lattice type filter 301' by the seventh circuit 17, and the fifth circuit 15 (or the output terminal) of the Lattice type filter 301 is connected to the sixth circuit 16 '(or the input terminal) of the second-order Lattice type filter 301' by the eighth circuit 18. The third circuit 13 of the first-order Lattice type filter 302 is connected to the first input terminal 1, the sixth circuit 16 is connected to the second input terminal 3, the fourth circuit 14 'of the second-order Lattice type filter 302' is connected to the first output terminal 2, and the fifth circuit 15 'of the second-order Lattice type filter 302' is connected to the second output terminal 4.
In other embodiments of the present application, the circuits 13-16 are connected to a plurality of resonators, and can also be directly connected to the output terminal or the input terminal via the electrodes of the resonators.
As shown in fig. 14-1, an embodiment of the present application provides a schematic circuit structure diagram of a two-order Lattice type filter, wherein a first-order Lattice type filter 302 and a second-order Lattice type filter 302 'are disposed on the same plane, surfaces of acoustic reflection layers of the first-order Lattice type filter 302 and the second-order Lattice type filter 302' are planes for circuit connection, and a seventh circuit 17 and an eighth circuit 18 are disposed on the planes.
As shown in fig. 14-2, a schematic circuit structure of a two-order Lattice type filter according to an embodiment of the present disclosure is shown, wherein a second-order Lattice type filter 302 'is longitudinally stacked above the first-order Lattice type filter 302, and a fifth acoustic reflective layer 403 and a sixth acoustic reflective layer 404 are disposed between the second-order Lattice type filter 301' and the first-order Lattice type filter 301. The fifth acoustic reflective layer 403 and the sixth acoustic reflective layer 404 have a similar structure to the first acoustic reflective layer, and are not described in detail herein. The fifth acoustic reflective layer 403 and the sixth acoustic reflective layer 404 are bragg reflective structures or phononic crystal structures. The surface of the acoustic reflection layer of the second-order Lattice type filter 302' located at the top is a plane of circuit connection on which the seventh circuit 17 and the eighth circuit 18 are disposed.
In an embodiment of the application, the second-order Lattice type filter 302' is longitudinally stacked above the first-order Lattice type filter 302, the Lattice type filter 302 includes a first resonator 210, a second resonator 220, a third resonator 230, and a fourth resonator 240, which are sequentially stacked from bottom to top, and an acoustic reflection layer is disposed between adjacent resonators. A tenth acoustic reflection layer is arranged between the second-order Lattice type filter 301' and the Lattice type filter 301. The tenth acoustic reflection layer is of a Bragg reflection structure or a phononic crystal structure. The surface of the acoustic reflection layer of the second-order Lattice type filter 302' on the top is a plane for circuit connection.
The filter provided by one embodiment of the application comprises a plurality of resonators, and the number of the resonators can be two or more. The resonators are longitudinally stacked, an acoustic reflection layer is arranged between every two adjacent resonators, and electrodes of the resonators extend to the surface of the acoustic reflection layer of the top filter through the second release holes. And connecting the resonators on the surface of the acoustic reflection layer according to a preset circuit design. The plurality of resonators may have the same resonant frequency or different resonant frequencies. The acoustic reflection layer is of a Bragg reflection structure or a phononic crystal structure.
As shown in fig. 15, a method for manufacturing a filter according to an embodiment of the present application includes:
s100, as shown in FIG. 15-1, etching a groove on the upper surface of the prepared silicon wafer to form a substrate 100 with a cavity 102; the substrate 100 is a silicon material.
S101, as shown in fig. 15-2, growing a sacrificial layer 101 on the surface of the substrate 100 by using a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, wherein the sacrificial layer 101 is deposited on the surface of the substrate 100, so that the cavity is filled with the sacrificial layer, as shown in fig. 15-3, and polishing the sacrificial layer to the surface of the substrate by using a chemical mechanical polishing method. The sacrificial layer comprises silicon dioxide.
S102, as shown in fig. 15-4, sequentially preparing a first bottom electrode, a first piezoelectric layer, and a first top electrode of a first resonator on the upper surface of the substrate filled with the sacrificial layer, where at least a portion of the first bottom electrode, at least a portion of the first piezoelectric layer, and at least a portion of the first top electrode are all disposed above the sacrificial layer, in a possible implementation manner provided by the present invention, depositing is sequentially performed by a magnetron sputtering method, and a first bottom electrode 211, a first piezoelectric layer 212, and a first top electrode 213 are prepared by patterning by a photolithography etching method, where the first bottom electrode 211, the first piezoelectric layer 212, and the first top electrode 213 are made into the first resonator 101. The first piezoelectric layer has piezoelectric property, and the material of the piezoelectric layer can be piezoelectric films such as piezoelectric ceramics (PZT), aluminum nitride (AlN) and zinc oxide (ZnO). The top electrode and the bottom electrode can be metal films of tungsten, molybdenum, aluminum, gold, platinum and the like.
And S103, growing a support layer 106 on the upper surface of the first top electrode by using an Atmospheric Pressure Chemical Vapor Deposition (APCVD) method as shown in FIGS. 15-5, and positioning the upper surface of the support layer and the upper surface of the first top electrode on the same plane by using a chemical mechanical polishing method as shown in FIGS. 15-6. The supporting layer can be silicon, silicon carbide and the like, and the silicon carbide materials can reduce energy loss.
S104, an acoustic reflection layer 107 is prepared on the upper surface of the first top electrode and the upper surface of the support layer. If the acoustic reflection layer is a bragg reflection structure, as shown in fig. 15-7, thin film materials with high and low acoustic impedances at intervals in the thickness direction are sequentially deposited by adopting a magnetron sputtering method. If the acoustic reflection layer is of a phononic crystal structure, depositing high and low acoustic impedance materials which are periodically distributed along a plurality of directions by adopting a magnetron sputtering method; the low acoustic impedance material may be silicon dioxide or the like; the high acoustic impedance material may be aluminum nitride, tungsten, molybdenum, or the like.
S105, as shown in fig. 15-8, sequentially preparing a second bottom electrode, a second piezoelectric layer and a second top electrode of a second resonator on the upper surface of the acoustic reflection layer; in one possible embodiment provided by the present application, the second bottom electrode 109, the second piezoelectric layer 110, and the second top electrode 111 are sequentially deposited by a magnetron sputtering method and patterned by a photolithography etching method, and the second bottom electrode 109, the second piezoelectric layer 110, and the second top electrode 111 are made into the second resonator 220. The second piezoelectric layer has piezoelectric property, and the material of the piezoelectric layer can be piezoelectric film such as piezoelectric ceramics (PZT), aluminum nitride (AlN), zinc oxide (ZnO) and the like. The top and bottom electrodes may be all metal films of tungsten, molybdenum, aluminum, gold, platinum, etc.
S106, as shown in fig. 15-9 and 15-10, sequentially etching the first resonator, the acoustic reflection layer, and the second resonator, preparing at least one first release hole 130 communicated with the sacrificial layer, and releasing the sacrificial layer through the at least one first release hole 130 to form a cavity structure.
S107, sequentially etching the acoustic reflection structure and the support layer as shown in fig. 15-11 and 15-12, forming a second release hole 131 connected to the first bottom electrode 211, preparing a third release hole 132 connected to the first top electrode, and filling a conductive material in the second release hole 131 or the third release hole 132, in an embodiment of the present invention, the first bottom electrode 211 and the first top electrode 213 are extended to the surface of the acoustic reflection layer 107 by electroplating the inner wall of the second release hole 131 or the third release hole 132. The conductive material or the plating material may be a conductive material such as copper, nickel, aluminum, gold, etc., which is schematically illustrated as a circuit connection manner and is not limited to the top electrode or the bottom electrode being made of the same material as the conductive material.
And S108, connecting the first resonator 210 and the second resonator 220 on the surface of the acoustic reflection layer 107 according to a preset circuit design, and forming the longitudinally integrated filter in the above embodiment.
It should also be understood that the reference herein to first, second, and various numerical designations is merely a convenient division to describe and is not intended to limit the scope of the present application.
In the present application, "and/or" describes an association relationship of associated objects, which means that there may be three relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In the present application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (a), b, or c", or "at least one (a), b, and c", may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The character "/" herein generally indicates that the former and latter associated objects are in an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used to describe various messages, requests, and terminals in embodiments of the present invention, these messages, requests, and terminals should not be limited by these terms. These terms are only used to distinguish messages, requests and terminals from one another. For example, a first terminal may also be referred to as a second terminal, and similarly, a second terminal may also be referred to as a first terminal, without departing from the scope of embodiments of the present invention.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (18)
1. A filter comprising at least two resonators, each resonator comprising a top electrode, a piezoelectric layer and a bottom electrode; the method is characterized in that: the at least two resonators are longitudinally stacked, an acoustic reflection layer is arranged between two adjacent resonators of the at least two resonators, the at least two resonators include a first resonator and a second resonator which are adjacently arranged,
the first resonator is positioned at the top of the filter, the second resonator is positioned below the first resonator, and a top electrode and a bottom electrode of the second resonator respectively extend to the surface of the acoustic reflection layer below the first resonator;
or the second resonator is positioned at the top of the filter, the first resonator is positioned below the second resonator, and the top electrode and the bottom electrode of the first resonator respectively extend to the surface of the acoustic reflection layer below the second resonator.
2. The filter of claim 1, wherein: the first resonator and the second resonator have different resonance frequencies.
3. The filter according to any of claims 1-2, wherein: the first resonator and the second resonator having different resonant frequencies include: the thickness of the piezoelectric layer of the first resonator and the thickness of the piezoelectric layer of the second resonator are different.
4. A filter according to any one of claims 1 to 3, characterized in that: the acoustic reflection layer is of a Bragg reflection structure and comprises low-acoustic-impedance materials and high-acoustic-impedance materials which are stacked alternately in the thickness direction.
5. A filter according to any one of claims 1 to 3, characterized in that: the acoustic reflection layer is of a phononic crystal structure and comprises low-acoustic-impedance materials and high-acoustic-impedance materials which are distributed along multiple directions.
6. The filter according to any of claims 1-5, wherein: the filter is a Ladder-type filter, the top electrode of the first resonator and the top electrode of the second resonator are both electrically connected with the first output end of the filter, the bottom electrode of the first resonator is grounded, and the bottom electrode of the second resonator is electrically connected with the first input end of the filter.
7. The filter of claim 6, wherein: the filter is a multi-order Ladder type filter comprising at least two Ladder type filters, the at least two Ladder type filters are connected in series, the Ladder type filter of the first order is connected with the first input end, and the Ladder type filter of the last order is connected with the first output end.
8. The filter of claim 7, wherein: the at least two Ladder type filters are arranged on the same plane.
9. The filter of claim 7, wherein: the at least two Ladder type filters are longitudinally stacked, wherein an acoustic reflection layer is arranged between every two adjacent Ladder type filters.
10. The filter according to any of claims 1-5, wherein: the filter is a Lattice type filter and comprises a first resonator, a second resonator, a third resonator and a fourth resonator, wherein the third resonator and the fourth resonator are longitudinally stacked, an acoustic reflection layer is arranged between the third resonator and the fourth resonator, a top electrode of the first resonator is electrically connected with a top electrode of the second resonator and then connected with a first input end of the filter, a bottom electrode of the third resonator is electrically connected with a bottom electrode of the fourth resonator and then connected with a second input end of the filter, a bottom electrode of the first resonator is electrically connected with a top electrode of the fourth resonator and then connected with a first output end of the filter, and a bottom electrode of the second resonator is electrically connected with a top electrode of the third resonator and then connected with a second output end of the filter.
11. The filter of claim 10, wherein: the third resonator is longitudinally stacked above a fourth resonator, a top electrode and a bottom electrode of the fourth resonator respectively extend to the surface of an acoustic reflection layer below the third resonator, the third resonator and the first resonator are arranged on the same plane, and the fourth resonator and the second resonator are arranged on the same plane;
or the third resonator is longitudinally stacked above a fourth resonator, a top electrode and a bottom electrode of the fourth resonator respectively extend to the surface of the acoustic reflection layer below the third resonator, the third resonator and the second resonator are arranged on the same plane, and the fourth resonator and the first resonator are arranged on the same plane;
or the fourth resonator is longitudinally stacked above a third resonator, a top electrode and a bottom electrode of the third resonator respectively extend to the surface of the acoustic reflection layer below the fourth resonator, the third resonator and the first resonator are arranged on the same plane, and the fourth resonator and the second resonator are arranged on the same plane;
or the fourth resonator is longitudinally stacked above the third resonator, a top electrode and a bottom electrode of the third resonator respectively extend to the surface of the acoustic reflection layer below the fourth resonator, the third resonator and the second resonator are arranged on the same plane, and the fourth resonator and the first resonator are arranged on the same plane.
12. The filter of claim 10, wherein: the first resonator, the second resonator, the third resonator and the fourth resonator are longitudinally stacked, and an acoustic reflection layer is arranged between the adjacent resonators.
13. The filter according to any one of claims 10 to 12, wherein: the filter is a multi-order Lattice type filter comprising at least two Lattice type filters, the at least two Lattice type filters are connected in series, the first-order Lattice type filter is electrically connected with the first input end and the second input end, and the last-order Lattice type filter is electrically connected with the first output end and the second output end.
14. The filter of claim 13, wherein: the at least two Lattice type filters are arranged on the same plane.
15. The filter of claim 13, wherein: the at least two Lattice type filters are longitudinally stacked, and an acoustic reflection layer is arranged between every two adjacent Lattice type filters.
16. A method for manufacturing a filter according to any one of claims 1 to 15, comprising the steps of:
preparing a substrate, wherein the substrate is provided with a cavity;
growing a sacrificial layer in a cavity of a substrate such that the cavity is filled with the sacrificial layer;
sequentially preparing a first bottom electrode, a first piezoelectric layer and a first top electrode of a first resonator on the upper surface of the substrate filled with the sacrificial layer, wherein at least one part of the first bottom electrode, at least one part of the first piezoelectric layer and at least one part of the first top electrode are all arranged above the sacrificial layer;
growing a supporting layer on the upper surface of the first top electrode, and grinding the supporting layer to enable the upper surface of the supporting layer and the upper surface of the first top electrode to be positioned on the same plane;
preparing an acoustic reflection layer on an upper surface of the first top electrode and an upper surface of the support layer;
sequentially preparing a second bottom electrode, a second piezoelectric layer and a second top electrode of a second resonator on the upper surface of the acoustic reflection layer;
sequentially etching the first resonator, the acoustic reflection layer and the second resonator, preparing at least one first release hole communicated with the sacrificial layer, and releasing the sacrificial layer through the at least one first release hole to form a cavity structure;
sequentially etching the sound reflection structure and the supporting layer, preparing a second release hole connected with the first bottom electrode, and filling a conductive material in the second release hole;
sequentially etching the sound reflection structure and the supporting layer, preparing a third release hole connected with the first top electrode, and filling a conductive material in the third release hole; the first resonator and the second resonator are electrically connected by a circuit on the surface of the acoustic reflection layer.
17. The method for manufacturing a filter according to claim 16, wherein: the acoustic reflection layer is of a Bragg reflection structure, and thin film materials with high and low acoustic impedance at intervals in the thickness direction are sequentially deposited by adopting a magnetron sputtering method; or the acoustic reflection layer is of a phononic crystal structure, and high and low acoustic impedance materials which are periodically distributed along a plurality of directions are deposited by adopting a magnetron sputtering method.
18. The method for manufacturing a filter according to claim 16 or 17, wherein: the support layer is Si or SiC, the low acoustic impedance material is silicon dioxide, and the high acoustic impedance material is aluminum nitride, tungsten or molybdenum.
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| CN202010724130.5A CN113972901A (en) | 2020-07-24 | 2020-07-24 | Filter and preparation method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023137769A1 (en) * | 2022-01-24 | 2023-07-27 | 华为技术有限公司 | Acoustic filter and electronic device |
| CN116633309A (en) * | 2023-05-25 | 2023-08-22 | 武汉敏声新技术有限公司 | Bulk acoustic wave resonator and preparation method thereof |
| EP4346100A1 (en) * | 2022-09-29 | 2024-04-03 | Qorvo US, Inc. | Reconfigurable acoustic wave resonators and filters |
-
2020
- 2020-07-24 CN CN202010724130.5A patent/CN113972901A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023137769A1 (en) * | 2022-01-24 | 2023-07-27 | 华为技术有限公司 | Acoustic filter and electronic device |
| EP4346100A1 (en) * | 2022-09-29 | 2024-04-03 | Qorvo US, Inc. | Reconfigurable acoustic wave resonators and filters |
| CN116633309A (en) * | 2023-05-25 | 2023-08-22 | 武汉敏声新技术有限公司 | Bulk acoustic wave resonator and preparation method thereof |
| CN116633309B (en) * | 2023-05-25 | 2024-03-19 | 武汉敏声新技术有限公司 | Bulk acoustic wave resonator and preparation method thereof |
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