Filter and electronic equipment

Abstract

The embodiment of the invention provides a filter and electronic equipment, and relates to the technical field of resonators. The filter comprises a substrate; the first resonator and the second resonator are arranged on the substrate, the first resonator comprises a first area of the substrate and a first piezoelectric layer arranged on the first area of the substrate, and a plurality of first electrodes are arranged on the first piezoelectric layer in the first direction; the second resonator comprises a second area of the substrate and a second piezoelectric layer arranged on the second area of the substrate; a plurality of second electrodes are arranged on the second piezoelectric layer along a second direction in parallel; the difference between the first direction and the second direction is 70-110 degrees. According to the embodiment of the invention, the first resonator and the second resonator can work in different working modes, so that additional manufacturing procedures of the filter for forming the first resonator and the second resonator can be reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of resonators, and in particular, to a filter and an electronic device. Background Art

[0002] A filter is a device that realizes the transmission characteristics of the passband and out-of-band by forming a certain frequency difference between series resonators and parallel resonators. Therefore, under the same manufacturing and structural conditions, the resonator should have good performance when acting as a series resonator and a parallel resonator. Summary of the Invention

[0003] The embodiments of the present application provide a filter and an electronic device, so that both the series resonator and the parallel resonator in the filter have good performance.

[0004] To achieve the above object, the embodiments of the present application adopt the following technical solutions:

[0005] In a first aspect, a filter is provided. The filter includes: a substrate; a first resonator and a second resonator on the substrate; wherein, the first resonator includes a first region of the substrate and a first piezoelectric layer disposed on the first region of the substrate, and a plurality of first electrodes are arranged side by side on the first piezoelectric layer along a first direction; the second resonator includes a second region of the substrate and a second piezoelectric layer disposed on the second region of the substrate; a plurality of second electrodes are arranged side by side on the second piezoelectric layer along a second direction; the first direction and the second direction differ by 70° - 110°.

[0006] For the filter provided in this embodiment, the first resonator and the second resonator are formed on the same substrate, and the propagation directions of the plurality of first electrodes in the first resonator and the plurality of second electrodes in the second resonator differ by 70° - 110°. Therefore, the first resonator and the second resonator can operate in different operating modes. For example, the first resonator operates in the first-order horizontal shear mode, and the second resonator operates in the first-order antisymmetric mode. Thus, the additional manufacturing procedures for forming the first resonator and the second resonator in the filter are reduced. For example, there is no need to make the first resonator and the second resonator have different piezoelectric layer thicknesses, ensuring the uniformity and thickness consistency of the substrate, and thus improving the in-chip performance uniformity, manufacturability, and reliability of the filter.

[0007] In some possible implementation manners, the first piezoelectric layer includes a first piezoelectric material. The Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30° ± 30°), or the crystal cutting angle and the propagation direction of the first piezoelectric material are X-cut and (30° ± 30°) Y direction. Wherein, the X direction of the first piezoelectric material is in the same direction as the thickness direction of the first piezoelectric layer, and the (30° ± 30°) Y direction of the first piezoelectric material is in the same direction as the first direction; the second piezoelectric layer includes a second piezoelectric material. The Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120° ± 30°), or the crystal cutting angle and the propagation direction of the second piezoelectric material are X-cut and (120° ± 30°) Y direction. Wherein, the X direction of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer, and the (120° ± 30°) Y direction of the second piezoelectric material is in the same direction as the second direction.

[0008] In this implementation manner, the first resonator uses X-cut and 30° ± 30° Y propagation direction, and the Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30° ± 30°) to obtain the maximum K 34 2 Thus, the first-order horizontal shear mode SH1 mode of the first resonator will be excited as the main resonance mode. The second resonator 320 uses X-cut and 120° ± 30° Y propagation direction, and the Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120° ± 30°) to obtain the maximum K 35 2 , so that the first-order antisymmetric mode A1 mode of the second resonator will be excited as the main resonance mode. Since the resonance modes of the first resonator and the second resonator are different, the sound velocities of the first piezoelectric layer and the second piezoelectric layer are also different. Therefore, the frequencies of the first resonator and the second resonator are also different, which can reduce the additional manufacturing procedures of the first resonator and the second resonator when forming the filter while ensuring the performance of the filter, and ensure the uniformity and thickness consistency of the substrate, thereby improving the in-chip performance uniformity, manufacturability, and reliability of the filter.

[0009] In some possible implementation manners, the first piezoelectric layer includes a first piezoelectric material. The Euler angles of the crystal of the first piezoelectric material are (0°, 90°, 0° ± 30°), or the crystal cutting angle and the propagation direction of the first piezoelectric material are Y-cut and (0° ± 30°)X direction, where the Y-cut of the first piezoelectric material is in the same direction as the thickness direction of the first piezoelectric layer, and the (0° ± 30°)X direction is in the same direction as the first direction; the second piezoelectric layer includes a second piezoelectric material. The Euler angles of the crystal of the second piezoelectric material are (0°, 90°, 90° ± 30°), or the crystal cutting angle and the propagation direction of the second piezoelectric material are Y-cut and (90° ± 30°)X direction, where the Y direction of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer, and the (90° ± 30°)X direction of the second piezoelectric material is in the same direction as the second direction.

[0010] In this implementation manner, the first resonator uses Y-cut and 0° ± 30°X propagation direction, and the Euler angles of the crystal of the first piezoelectric material are (0°, 90°, 0° ± 30°) to obtain the maximum K 34 2 Thus, the first-order horizontal shear mode SH1 mode of the first resonator will be excited as the main resonance mode. The second resonator uses Y-cut and 90° ± 30°X propagation direction, and the Euler angles of the crystal of the second piezoelectric material are (0°, 90°, 90° ± 30°) to obtain the maximum K 35 2 , so that the first-order antisymmetric mode A1 mode of the second resonator will be excited as the main resonance mode. Since the resonance modes of the first resonator and the second resonator are different, the sound velocities of the first piezoelectric layer and the second piezoelectric layer are also different, and thus the frequencies of the first resonator and the second resonator are also different. While ensuring the performance of the filter, it is possible to reduce the additional manufacturing procedures of the first resonator and the second resonator when forming the filter, ensure the uniformity and thickness consistency of the substrate, and thus improve the in-chip performance uniformity, manufacturability, and reliability of the filter.

[0011] In some possible implementation manners, the first resonator further includes: a third electrode disposed between the first region of the substrate and the first piezoelectric layer. Thus, an electric field can be generated between the first electrode and the third electrode along the thickness direction of the first piezoelectric layer, and the first piezoelectric layer utilizes this electric field to form a piezoelectric effect, thereby generating the conversion between electrical energy and mechanical energy.

[0012] In some possible implementation manners, the second resonator further includes: a fourth electrode disposed between the second region of the substrate and the second piezoelectric layer. Thus, an electric field can be generated between the second electrode and the fourth electrode along the thickness direction of the second piezoelectric layer, and the second piezoelectric layer utilizes this electric field to form a piezoelectric effect, thereby generating the conversion between electrical energy and mechanical energy. In some possible implementation manners, the thicknesses of the first piezoelectric layer and the second piezoelectric layer are equal. Thus, the additional manufacturing processes for forming the first resonator and the second resonator can be reduced, the uniformity of the substrate is ensured, and the reliability of the filter can be improved.

[0013] In some possible implementation manners, the first resonator further includes: a first bus bar and a second bus bar; among every two adjacent first electrodes of the plurality of first electrodes, one is a first interdigital electrode and the other is a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are spaced apart in the first direction; the plurality of first interdigital electrodes among the plurality of first electrodes are connected through the first bus bar, and the plurality of second interdigital electrodes among the plurality of first electrodes are connected through the second bus bar.

[0014] In this implementation manner, the first bus bar can be used as the input end, and the second bus bar can be used as the output end. For example, an alternating voltage within a certain frequency range can be input to the plurality of first interdigital electrodes through the first bus bar, and the plurality of second interdigital electrodes output the alternating voltage signal processed by the first resonator through the second bus bar.

[0015] In some possible implementation manners, the second resonator further includes: a third bus bar and a fourth bus bar; among every two adjacent second electrodes of the plurality of second electrodes, one is a third interdigital electrode and the other is a fourth interdigital electrode; the third interdigital electrode and the fourth interdigital electrode are spaced apart in the second direction; the plurality of third interdigital electrodes among the plurality of second electrodes are connected through the third bus bar, and the plurality of fourth interdigital electrodes among the plurality of second electrodes are connected through the fourth bus bar.

[0016] In this implementation manner, the third bus bar can be used as the input end, and the fourth bus bar can be used as the output end. For example, an alternating voltage within a certain frequency range can be input to the plurality of third interdigital electrodes through the third bus bar, and the plurality of fourth interdigital electrodes output the alternating voltage signal processed by the second resonator through the fourth bus bar.

[0017] In some possible implementation manners, the second finger pitch P2 is equal to the first finger pitch P1, where the width dimension of each third interdigital electrode is s3, and the distance between every two adjacent third interdigital electrodes and fourth interdigital electrodes is s4, and the second finger pitch P2 = s3 + s4. Thus, it is possible to prevent the parasitic resonance frequency position generated by the first resonator or the second resonator from possibly approaching the main resonance frequency position, thereby affecting the in-band insertion loss performance and out-of-band rejection performance of the filter.

[0018] In some possible implementations, the first resonator further includes: a first dielectric layer disposed between the first region of the substrate and the third electrode. Thus, by disposing the first dielectric layer between the substrate and the third electrode, the direct coupling between the first piezoelectric layer and the substrate is weakened, and further, the electromechanical coupling coefficient of the first resonator can be increased.

[0019] In some possible implementations, the material of the first piezoelectric layer includes at least one combination of a combination of niobium, lithium, and oxygen, a combination of tantalum, lithium, and oxygen.

[0020] In some possible implementations, the filter further includes a passivation layer covering the first resonator and the second resonator.

[0021] In this implementation, the passivation layer can protect the first resonator and the second resonator from corrosion, scratching, oxidation, etc., and protect the performance of the device. In addition, the passivation layer can also adjust the resonance frequencies of the first resonator and the second resonator by different thicknesses, and can also adjust the electromechanical coupling coefficient and the temperature coefficient of the resonator.

[0022] In some possible implementations, the third electrode has opposite first and second surfaces, the first surface is located on the side close to the first piezoelectric layer; a cavity is provided in the first region of the substrate, at least part of the second surface of the third electrode is used to enclose the cavity, and at least part of the third electrode is disposed between the cavity and the first piezoelectric layer.

[0023] In some possible implementations, the first resonator further includes: a stacked first reflective layer and second reflective layer; the first reflective layer and the second reflective layer are disposed between the first region of the substrate and the third electrode.

[0024] In some possible implementations, the third electrode has opposite first and second surfaces, the first surface is located on the side close to the first piezoelectric layer, and the second surface of the third electrode is attached to the first part of the substrate.

[0025] In some possible implementations, the first finger pitch P1 satisfies: Where: Vs is the shear body wave velocity of the substrate, f1 is the operating frequency of the first resonator; wherein, the width dimension of each first interdigital electrode is s1, the spacing between every two adjacent first interdigital electrodes and second interdigital electrodes is s2, and the first finger pitch P1 = s1 + s2.

[0026] In this implementation, the substrate is a high sound velocity substrate. When the first finger pitch P1 satisfies: the leakage of resonance energy to the substrate layer can be effectively suppressed to improve the quality factor Q value and the electromechanical coupling coefficient of the first resonator.

[0027] In a second aspect, an electronic device is provided. The electronic device includes: a control circuit; a filter electrically connected to the control circuit.

[0028] Among them, for the technical effects brought about by any possible implementation manner in the second aspect, reference may be made to the technical effects brought about by different implementation manners in the first aspect above, which will not be elaborated here. Description of the Drawings

[0029] Figure 1 Partial structural schematic diagram of the electronic device provided by an embodiment of the present application;

[0030] Figure 2 Partial structural schematic diagram of the electronic device provided by an embodiment of the present application;

[0031] Figure 3 Partial structural schematic diagram of the filter in the electronic device provided by an embodiment of the present application;

[0032] Figure 4 Admittance curve diagram of resonators with different thickness passivation layers provided by an embodiment of the present application;

[0033] Figure 5 Partial structural schematic diagram of the resonator provided by an embodiment of the present application;

[0034] Figure 6 For Figure 5 Admittance curve diagram of the shown resonator;

[0035] Figure 7 Structural schematic diagram of a filter provided by an embodiment of the present application;

[0036] Figure 8 Structural schematic diagram of a filter provided by an embodiment of the present application;

[0037] Figure 9 Structural schematic diagram of a filter provided by an embodiment of the present application;

[0038] Figure 10 Structural schematic diagram of a filter provided by an embodiment of the present application;

[0039] Figure 11 Structural schematic diagram of a filter provided by an embodiment of the present application;

[0040] Figure 12 Admittance curve diagram of the filter provided by an embodiment of the present application;

[0041] Figure 13 Dispersion curve diagram of a filter provided by an embodiment of the present application;

[0042] Figure 14 The admittance curve diagram of a filter provided by an embodiment of the present application;

[0043] Figure 15 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0044] Figure 16 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0045] Figure 17 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0046] Figure 18 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0047] Figure 19 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0048] Figure 20 The structural schematic diagram of a filter provided by an embodiment of the present application;

[0049] Figure 21 is Figure 20 the admittance curves of each resonator in

[0050] Figure 22 The top view of a filter provided by an embodiment of the present application. Detailed implementation manners

[0051] Before introducing the structures that can be implemented by the embodiments of the present application, the technical terms related to the embodiments of the present application are first introduced.

[0052] Piezoelectric effect: including the direct piezoelectric effect and the inverse piezoelectric effect. The direct piezoelectric effect means that when a piezoelectric material is subjected to a mechanical force, its polarization will change; while the inverse piezoelectric effect means that after an external electric field is applied to the piezoelectric material, the material will deform. The main reasons for the piezoelectric effect are mainly the anisotropy of the crystal structure of the piezoelectric material itself and the polarization effect.

[0053] Main resonance mode, parasitic mode: The position of the parasitic resonance frequency generated by the resonator may be close to the main resonance frequency position. The parasitic resonance may affect the main resonance mode, and thus affect the in-band insertion loss performance and out-of-band rejection performance of the filter. The parasitic resonance of the resonator is usually called a mode, or a parasitic mode. When the mode falls near the main resonance mode, for example, near the resonance point and anti-resonance point of the main resonance mode, it will affect the in-band insertion loss performance and out-of-band rejection performance of the filter.

[0054] Piezoelectric coupling factor Kt 2 : is a key parameter of the resonator, the electromechanical coupling coefficient K t 2 can reflect the conversion efficiency between mechanical energy and electrical energy. The electromechanical coupling coefficient K of the resonator t 2 determines the relative frequency width between the anti-resonant frequency and the resonant frequency of the resonator. For example, when the resonator is used in filter design, this relative frequency width directly determines the bandwidth of the filter. It can be considered that the electromechanical coupling coefficient K t 2 is larger, the bandwidth of the filter built by the ladder structure can also be larger, and the performance is better.

[0055] The electromechanical coupling coefficient component k xy 2 : For single-crystal piezoelectric materials, it has a fourth-order elastic tensor c, a third-order piezoelectric tensor e, and a second-order dielectric tensor ε. According to the right-handed rectangular coordinate system, it has elastic tensor components c ijkl , piezoelectric tensor components e ijk , dielectric tensor components ε ij , where i, j, k, l = {1, 2, 3}. Due to the symmetry of the single-crystal structure, for example, c 1323 = c 3132 , the order of the components can be simplified. Define {23, 32} → 4, {13, 31} → 5, {12, 21} → 6. For example, c 1323 = c 3132 → c 54 , then there are elastic tensor components c xy (6*6), piezoelectric tensor components e ix (3*6), dielectric tensor components ε ij (3*3), where i, j = {1, 2, 3}, x, y = {1, 2, 3, 4, 5, 6}. The electromechanical coupling coefficient component k xy 2 is calculated from the elastic tensor components, piezoelectric tensor components, and dielectric tensor components of the material. The formula is:

[0056]

[0057] where, x = {1, 2, 3}, y = {1, 2, 3, 4, 5, 6}, ε xx S is the dielectric tensor component under fixed strain, c yy E is the elastic tensor component under fixed electric field strength.

[0058] The calculation methods and formulas of each elastic tensor component, piezoelectric tensor component, and dielectric tensor component at different crystal Euler angles are as follows.

[0059] For the crystal orientation of a piezoelectric material with Euler angles (0, 0, 0), taking LN as an example,

[0060] c E 11 = 2.03, c E 12 = 0.53, c E 13 = 0.75, c E 14 = 0.09, c E 44 = 0.60, c E 33 = 2.43, c E 22 = c E 11 , c E 23 = c E 13 , c E 24 = -c E 14 , c E 55 = c E 44 , c E 56 = c E 14 , c E 66 = (c E 11 - c E 12 ) / 2, with the unit of *10 11 N / m 2 ;

[0061] e 15 = 3.70, e 16 = -2.53, e 31 = 0.19, e 33 = 1.31, e 21 = e 16 , e 22 = -e 16 , e 24 = e 15 , e 32 = e 31 , with the unit of C / m 2 ; ε S 11= 43.6 * ε 0 , ε S 33 = 29.2 * ε 0 , ε S 22 = ε S 11 , where ε 0 is the vacuum permittivity, 8.85 * 10 -12 F / m. The remaining components can be obtained through tensor symmetry, and the components without values are zero. Among them, the components are expressed in simplified form. For the fourth-order elastic tensor component c E ijkl , the third-order piezoelectric tensor component e ijk , they can be expanded accordingly.

[0062] Now, for the crystal orientation of the piezoelectric material with Euler angles (α, β, γ), its corresponding elastic tensor component piezoelectric tensor component e pqr ’, dielectric tensor component can be calculated by the following formulas:

[0063] c E pqrs ’ = c E ijkl A ip A jq A kr A ls ;

[0064] e pqr ’ = e ijk A ip A jq A kr ;

[0065] ε S pq ’ = ε S ij A ip A jq ;

[0066] The formulas adopt the Einstein summation convention, where the 3 * 3 matrix A = (cosαcosγ - sinαcosβsinγ, -cosαsinγ - sinαcosβcosγ, sinαsinβ; sinαcosγ + cosαcosβsinγ, -sinαsinγ + cosαcosβcosγ, -cosαsinβ; sinβsinγ, sinβcosγ, cosβ).

[0067] The electromechanical coupling coefficient K t2 and the electromechanical coupling coefficient component k xy 2 The relationship of the electromechanical coupling coefficient K t 2 is determined by the electromechanical coupling coefficient component k xy 2 and the mode excited by a specific resonator structure. Generally speaking, the larger the k xy 2 corresponding to the main resonance mode of the resonator, the larger the K t 2 of the resonator. For example, when the piezoelectric material is selected as lithium niobate (LN), the maximum electromechanical coupling coefficient component k xy 2 of LN can reach 0.9253. The resonator using this component to generate the main resonance mode has relatively large overall electromechanical coupling performance. For example, the electromechanical coupling coefficient K t 2 of the resonator can reach 25%. And generally speaking, the larger the electromechanical coupling coefficient component k xy 2 corresponding to the main resonance mode, the smaller the other electromechanical coupling coefficient components k xy 2 , and the resonator shows a larger electromechanical coupling coefficient and smaller parasitic hybrid modes.

[0068] For a given resonator structure, one resonance mode corresponds to one electromechanical coupling coefficient component k xy 2 . For example, the maximum electromechanical coupling coefficient component k xy 2 of LN can include k 16 2 , k 15 2 , k 34 2 , k 35 2 . Exciting these maximum electromechanical coupling coefficient components k xy 2 generates the main resonance mode, and the modes generated by the other electromechanical coupling coefficient components can be hybrid modes. For example, in XBAR, exciting the maximum electromechanical coupling coefficient component k 16 2 generates the zero-order shear horizontal mode (SH0 mode) of the main resonance mode; in YBAR, exciting the maximum electromechanical coupling coefficient component k 34 2, the first-order shear horizontal mode (SH1 mode) of the main resonance mode is generated; in the YBAR, the maximum electromechanical coupling coefficient component k 35 2 , the first-order anti-symmetry mode (A1 mode) of the main resonance mode is generated.

[0069] Quality factor (Q): It represents the energy utilization rate of the device, that is, within one vibration cycle, the ratio of the total energy received by the device to the dissipated energy. In the design of filters, the electromechanical coupling coefficient K of the resonators that make up the filter t 2 and the Q value of the quality factor are both important parameters.

[0070] Euler angle of the piezoelectric material: The Euler angle characterizes the relative rotation angle relationship between the direction perpendicular to or parallel to the resonator finger extension direction in the wafer plane and the X direction or Y direction of the original piezoelectric crystal structure.

[0071] Admittance: In power electronics, admittance is defined as the reciprocal of impedance, symbol Y, with the unit of Siemens, abbreviated as S. Like impedance, admittance is also a complex number, composed of a real part (conductance G) and an imaginary part (susceptance B): Y = G + jB.

[0072] Admittance curve abs and admittance curve Re: The admittance curve abs(Y) = |Y|, which is the modulus (also called the amplitude) of Y, representing the overall response of the resonator. Re(Y) is the real part of Y, that is, the conductance G, representing the loss of the resonator.

[0073] R-a-R range: The frequency range around the resonance frequency fr and the anti-resonance frequency fa. For example, the R-a-R range is (fr - (fa - fr) to (fa + (fa - fr)).

[0074] Electromechanical coupling R-aR: Based on the relative bandwidth of the resonance frequency fr and the anti-resonance frequency fa, it is used to represent the electromechanical coupling coefficient of the resonator. For example, the R-aR of the resonator should be equivalent to the relative bandwidth of the target filter. Among them, R-aR = (fa - fr) / ((fa + fr) / 2).

[0075] Embodiments of the present application provide an electronic device, which includes, but is not limited to, products such as a radio frequency front end and a filtering and amplifying module, and may also include terminal devices such as mobile phones, tablets, smart wearable products (e.g., smart watches, smart bracelets), virtual reality (VR) devices, augmented reality (AR), drones, or may also be devices such as base stations, televisions, routers, and automobiles. Embodiments of the present application do not impose special restrictions on the specific form of the above-mentioned electronic device.

[0076] In an electronic device such as the above, as Figure 1 shown, the electronic device 100 may include a control circuit 110 and a filter 200. The control circuit 110 is connected to the filter 200 and is used to control the filter 200 to effectively filter out a specific frequency point in the signal or frequencies other than the frequency point, so as to obtain a signal with a specific frequency or a signal after eliminating a specific frequency, thereby improving the working performance of the electronic device 100.

[0077] Figure 2 Some circuit diagrams in some electronic devices 100 are given. Among them, see Figure 2 , the electronic device 100 includes a receiver 600, a transmitter 700, an antenna 500, and a baseband chip 800. The antenna 500 is electrically connected to the receiver 600 and the transmitter 700 respectively through a switch 900, and the receiver 600 and the transmitter 700 are electrically connected to the baseband chip 800 respectively.

[0078] In Figure 2 the shown receiver 600, it includes a filter 60a and a filter 60c. A low-noise amplifier 60b is electrically connected between the filter 60a and the filter 60c. The filter 60c is electrically connected to a buffer 60e through a mixer 60d, and the buffer 60e is electrically connected to a voltage-controlled oscillator 60f. Figure 2 This is only an exemplary receiver, and electronic devices can be added or reduced based on this circuit structure.

[0079] In Figure 2 the shown transmitter 700, it includes a power amplifier (PA) 70b. The power amplifier 70b is electrically connected to a filter 70a and a driver 70c respectively, and the driver 70c is electrically connected to a voltage-controlled oscillator 70d. Similarly, Figure 2It is only an exemplary transmitter, and electronic devices can be added or reduced based on this circuit structure.

[0080] For example, in Figure 2 the transmitter 700 shown, the filter can effectively filter out specific frequency points amplified by the power amplifier or frequencies outside that frequency point, or the filter can filter out the noise of the low-noise amplifier.

[0081] Again, Figure 3 as shown, the filter 200 can include a plurality of serially connected resonators 300a, or include a plurality of parallel-connected resonators 300b, or include serially connected resonators 300a and parallel-connected resonators 300b. It can be understood that hereinafter, the parallel-connected resonators will be simply referred to as parallel resonators, and the serially connected resonators will be simply referred to as series resonators.

[0082] In order to enable the resonator to have good performance when acting as a series resonator and a parallel resonator, in an alternative example, the series resonator and the parallel resonator have different finger spacings, but the frequency gap between the series resonator and the parallel resonator cannot be covered by different finger spacings, and at the same time, it will also cause the parasitic resonance frequency position generated by the resonator to be possibly close to the main resonance frequency position, and the parasitic resonance may affect the main resonance mode, thereby affecting the in-band insertion loss performance and out-of-band rejection performance of the filter.

[0083] In another alternative example, the series resonator and the parallel resonator have different passivation layer thicknesses, but as the passivation layer thickness increases, the performance of the resonator also decreases. In Figure 4 the schematic diagram of the admittance curve shown, it includes the modulus (abs) and the real part (Re) of the admittance curve. Among them, Figure 4 in (i) shows the schematic diagram of the admittance curve of the resonator without a passivation layer, and the electromechanical coupling coefficient K of this resonator t 2 is 20.5%, and the electromechanical coupling R-aR is 9.5%. As the thickness of the passivation layer increases, Figure 4 in (ii) shows the schematic diagram of the admittance curve of the resonator when the passivation layer thickness is 25 nm, and the electromechanical coupling coefficient K of this resonator t 2 is 19.9%, and the electromechanical coupling R-aR is 9.5%; Figure 4 in (iii) shows the schematic diagram of the admittance curve of the resonator when the passivation layer thickness is 50 nm, and the electromechanical coupling coefficient K of this resonator t 2 is 15.4%, and the electromechanical coupling R-aR is 6.9%; when the passivation layer thickness is 120 nm, the electromechanical coupling coefficient K of this resonator t2 is 7.1%, and the electromechanical coupling R-aR is 3.0%. It can be seen that as the thickness of the passivation layer increases, the electromechanical coupling coefficient K of the resonator t 2 is smaller, and the bandwidth of the filter constructed by the trapezoidal structure can also be smaller, so the performance of the filter decreases accordingly.

[0084] In another alternative example, the series resonator and the parallel resonator have different piezoelectric layer thicknesses. Refer to Figure 5 the structural schematic diagram of the filter shown in Figure 6 and the admittance curve schematic diagram shown in Figure 6 The shown admittance curve includes the modulus (abs) and the real part (Re) of the admittance curve. Figure 6 In (i) is the admittance schematic diagram of the series resonator, Figure 6 In (ii) is the admittance schematic diagram of the parallel resonator. In this example, the piezoelectric layer thickness of the series resonator is 280 nm, the finger pitch is 0.67 um, and the electromechanical coupling coefficient K of the series resonator t 2 is 25.4%, and the electromechanical coupling R-aR is 12.2%. The piezoelectric layer thickness of the parallel resonator is 380 nm, the finger pitch is 0.64 um, and the electromechanical coupling coefficient K of the parallel resonator t 2 is 23.9%, and the electromechanical coupling R-aR is 11.4%. It can be seen that the series resonator and the parallel resonator have good performance, but the reduced piezoelectric layer will reduce the quality factor of the series resonator, thereby reducing the reliability of the series resonator.

[0085] Therefore, under the same manufacturing and structural conditions, how to make the resonator have good performance both as a series resonator and a parallel resonator is a much-needed technical solution. It will greatly contribute to the filter performance of the actual manufacturing process, prevent the frequency or electromechanical coupling offset on the entire wafer scale, so as to facilitate the smooth progress of mass production later.

[0086] For this reason, the embodiments of the present application provide a filter. Refer to Figure 7, the filter includes a substrate 10; a first resonator 310 and a second resonator 320 disposed on the substrate 10; wherein, the first resonator 310 includes a first region 101 of the substrate 10, and a first piezoelectric layer 201 disposed on the first region 101 of the substrate 10, and a plurality of first electrodes 401 are arranged side by side along a first direction on the first piezoelectric layer 201; the second resonator 320 includes a second region 102 of the substrate 10, and a second piezoelectric layer 202 disposed on the second region 102 of the substrate 10; a plurality of second electrodes 402 are arranged side by side along a second direction on the second piezoelectric layer 202; the first direction and the second direction differ by 70°-110°.

[0087] The above Figure 7 In the exemplary filter, the first resonator includes a plurality of first electrodes 401 arranged along a first direction, the second resonator includes a plurality of second electrodes 402 arranged along a second direction, and the first direction and the second direction differ by 70°-110°. The first direction can be understood as a direction perpendicular to or nearly perpendicular to the extending direction of the second electrode 402. In one embodiment, the first direction is parallel to the extending direction of the first piezoelectric layer 201; or rather, the first direction is perpendicular to the stacking direction of the first piezoelectric layer 201 and the first electrode 401.

[0088] In the filter provided in this embodiment, the first resonator 310 and the second resonator 320 are formed on the same substrate 10, and the propagation directions of the plurality of first electrodes 401 in the first resonator 310 and the plurality of second electrodes 402 in the second resonator 320 differ by 70°-110°. Therefore, the first resonator 310 and the second resonator 320 can operate in different operating modes. For example, the first resonator 310 can be a parallel resonator, and the second resonator 320 is a series resonator, thereby reducing the additional manufacturing procedures for the parallel resonator and the parallel resonator. For example, there is no need to make the parallel resonator and the series resonator have different piezoelectric layer thicknesses, ensuring the uniformity of the substrate 10, and thus improving the reliability of the filter.

[0089] In an alternative embodiment, refer to Figure 8 A partial process structure diagram of a filter shown. The filter includes a substrate 10; a first resonator 310 and a second resonator 320 disposed on the substrate 10; wherein, the first resonator 310 includes a first region 101 of the substrate 10, and a third electrode 501 and a first piezoelectric layer 201 stacked on the first region 101 of the substrate 10, and a plurality of first electrodes 401 are arranged side by side along a first direction on the first piezoelectric layer 201; the second resonator 320 includes a second region 102 of the substrate 10, and a fourth electrode 502 and a second piezoelectric layer 202 stacked on the second region 102 of the substrate 10; a plurality of second electrodes 402 are arranged side by side along a second direction on the second piezoelectric layer 202.

[0090] Figure 8 The first resonator 310 and the second resonator 320 in the exemplary structure may be thin-film plate-wave resonators. The main principle of the thin-film plate-wave resonator is to utilize the piezoelectric effect characteristics of piezoelectric materials. The input and output transducers are used to convert the input signal of the radio wave into mechanical energy. After processing, the mechanical energy is then converted back into an electrical signal to achieve the goal of filtering unnecessary signals and noise and improving the reception quality.

[0091] Figure 8 When the shown first resonator 310 is operating, the third electrode 501 may not be electrically connected. An alternating voltage of a certain frequency is applied to the first electrode 401, such that an electric field E is generated between the first electrode 401 and the third electrode 501 along the thickness direction of the first piezoelectric layer 201. The first piezoelectric layer 201 utilizes this electric field to form a piezoelectric effect. Figure 8 The example utilizes the vertical electric field E to excite the first piezoelectric layer 201 to generate resonance, thereby generating the conversion between electrical energy and mechanical energy.

[0092] Figure 8 The shown first resonator 310 utilizes the electric field in the thickness direction of the first piezoelectric layer 201 to excite resonance. In one embodiment, it can be referred to as a vertically-excited bulk acoustic resonator (YBAR). Here, the thickness direction of the first piezoelectric layer 201 can be understood as the direction parallel to the stacking direction of multiple film layers (substrate 10, third electrode 501, first piezoelectric layer 201) on the first piezoelectric layer 201.

[0093] It can be understood that the working principle and process of the second resonator 320 are similar to those of the first resonator 310. For the specific details, reference can be made to the above working principle and process, and the embodiments of the present application will not be elaborated herein.

[0094] In the filter according to the embodiments of the present application, such as Figure 9 , in some examples, the first piezoelectric layer 201 in this embodiment includes a first piezoelectric material, and the Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30° ± 30°); alternatively, it can be understood that the crystal cutting angle and propagation direction of the first piezoelectric material are X-cut and (30° ± 30°) Y-direction.

[0095] The "X" in the above X-cut represents the X-direction of the first piezoelectric material. The X-cut can be used to represent the X-direction of the first piezoelectric material and the thickness direction of the first piezoelectric layer 201 (such as Figure 9 the Y in 1The propagation direction of the first resonator is parallel to the surface of the first piezoelectric layer 201 and perpendicular to the extension direction of the first electrode 401, and in one embodiment, the (30° ± 30°) Y direction of the first piezoelectric material is in the same direction as the first direction.

[0096] The second piezoelectric layer 202 in this embodiment includes a second piezoelectric material, and the Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120° ± 30°); alternatively, it can be understood that the crystal cutting angle and the propagation direction of the second piezoelectric material are X-cut and (120° ± 30°) Y direction. Among them, the X direction of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer 202, and the (120° ± 30°) Y direction of the second piezoelectric material is in the same direction as the second direction.

[0097] The "X" in the above X-cut represents the X direction of the second piezoelectric material, and the X-cut can be used to indicate that the X direction of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer 202 (such as Figure 9 the Y in 1 direction) is in the same direction. The propagation direction of the second piezoelectric material is parallel to the surface of the second piezoelectric layer 202 and perpendicular to the extension direction of the second electrode 402. In one embodiment, the (120° ± 30°) Y direction of the second piezoelectric material is in the same direction as the second direction.

[0098] It can be understood that the "same direction" involved above is defined to allow a certain error and can be close to the same direction. In one embodiment, the difference between the two angles within 5° (including 5°) can be regarded as close to the same direction.

[0099] The limitations of the Euler angles, cutting angles or propagation directions involved in the embodiments of the present application, for example, the tangential general accuracy of the first piezoelectric material and the second piezoelectric material is < ±0.5°, such as: X-cut ±0.5°, Y-cut ±0.5°, etc. In the form of Euler angles, it is (90° ± 0.5°, 90° ± 0.5°, 30° ± 30°) or (90° ± 0.5°, 90° ± 0.5°, 120° ± 30°).

[0100] For example, the Euler angle can be (89.5°, 90.5°, 0°), or the Euler angle can be (89.5°, 90.5°, 30°), or the Euler angle can be (89.5°, 90.5°, 90°), or the Euler angle can be (89.5°, 90°, 40°), or the Euler angle can be (90°, 90°, 10°).

[0101] For example, the Euler angles can be (90.5°, 89.5°, 90°), or the Euler angles can be (90°, 90.5°, 120°), or the Euler angles can be (90°, 90.5°, 110°), or the Euler angles can be (90.5°, 90.5°, 100°), or the Euler angles can be (90.5°, 90°, 115°).

[0102] In this embodiment, the first resonator 310 can use an X cut and a 30° ± 30° Y propagation direction. The Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30° ± 30°) to obtain the maximum K 34 2 Thus, the first-order shear horizontal mode (SH1 mode) of the first resonator 310 will be excited as the main resonance mode. In the SH1 main resonance mode, the vibration direction is Figure 9 the direction z shown, that is, the vibration direction is parallel to the substrate surface and perpendicular to the first direction.

[0103] The second resonator 320 can use an X cut and a 120° ± 30° Y propagation direction. The Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120° ± 30°) to obtain the maximum K 35 2 Thus, the first-order anti-symmetry mode (A1 mode) of the second resonator 320 will be excited as the main resonance mode. In the A1 main resonance mode, the main vibration direction is Figure 9 the direction X shown 1 that is, parallel to the second direction. In some examples, in the A1 main resonance mode, the direction Y will also be driven 1 to vibrate.

[0104] The direction X involved in the embodiment of the present application 1 and the direction Y 1 and the direction Z 1 are different from the X direction and the Y direction in the first piezoelectric layer, and are also different from the X direction and the Y direction in the second piezoelectric layer. The direction X 1 can be understood as parallel to the substrate surface and parallel to the first direction, the direction Y 1 is parallel to the thickness direction of the first piezoelectric layer 201, and the direction Z 1 is parallel to the substrate surface and perpendicular to the first direction.

[0105] Since the resonance modes of the first resonator 310 and the second resonator 320 are different, the sound velocities of the first piezoelectric layer 201 and the second piezoelectric layer 202 are also different. As a result, the frequencies of the first resonator and the second resonator are different. This can reduce the additional manufacturing processes of the first resonator 310 and the second resonator 320 when forming the filter while ensuring the performance of the filter, guarantee the uniformity of the substrate, and thus improve the reliability of the filter.

[0106] Combined with Figure 10 and Figure 11 , Figure 11 shows a process structure diagram of a filter. Figure 11 shows Figure 10 the distribution diagrams of the first electrode 401 and the second electrode 402 in Figure 10 . On the side of the first piezoelectric layer 201 in

[0107] that is far from the third electrode 501, a plurality of first electrodes 401 are provided. The plurality of first electrodes 401 includes a plurality of first interdigital electrodes 4011 and a plurality of first interdigital electrodes 4012. For example, along a direction perpendicular to the extending direction of the first interdigital electrode 4011, the plurality of first interdigital electrodes 4011 and the plurality of first interdigital electrodes 4012 can be arranged side by side, and the plurality of first interdigital electrodes 4011 and the plurality of first interdigital electrodes 4012 are arranged at intervals, that is, a first interdigital electrode 4012 can be provided between two adjacent first interdigital electrodes 4011. Alternatively, the first interdigital electrode 4011 and the first interdigital electrode 4012 are spaced in a first direction, and the extending direction of the first interdigital electrode 4011 and / or the first interdigital electrode 4012 is perpendicular to the first direction. Figure 11 As shown in

[0108] , the first bus bar 403 and the second bus bar 404 are arranged in parallel, and the first bus bar 403 and the second bus bar 404 both extend along a direction perpendicular to the extending direction of the first interdigital electrode 4011 or the first interdigital electrode 4012. As

[0109] shown, the first bus bar 403 and the second bus bar 404 extend along the 30° Y direction. Where: Vs is the shear body wave velocity of the substrate 10, and f1 is the operating frequency of the first resonator 310; wherein, the width of each first interdigital electrode 4011 is s1, the spacing between every two adjacent first interdigital electrodes 4011 and first interdigital electrode 4012 is s2, and the first finger pitch (Pitch) P1 is the sum of the width s1 and the spacing s2. This can prevent energy from leaking towards the substrate 10 and improve the Q value and electromechanical coupling coefficient of the first resonator 310.

[0110] On the side of the second piezoelectric layer 202 in Figure 11 away from the fourth electrode 502, a plurality of second electrodes 402 are provided. The plurality of second electrodes 402 include a plurality of third interdigital electrodes 4021 and a plurality of fourth interdigital electrodes 4022. For example, along a direction perpendicular to the extending direction of the third interdigital electrodes 4021, the plurality of third interdigital electrodes 4021 and the plurality of fourth interdigital electrodes 4022 can be arranged side by side, and the plurality of third interdigital electrodes 4021 and the plurality of fourth interdigital electrodes 4022 are arranged at intervals, that is, a fourth interdigital electrode 4022 can be arranged between two adjacent third interdigital electrodes 4021. Alternatively, the third interdigital electrodes 4021 and the fourth interdigital electrodes 4022 are spaced in a second direction, and the extending direction of the third interdigital electrodes 4021 and / or the fourth interdigital electrodes 4022 is perpendicular to the second direction.

[0111] The plurality of third interdigital electrodes 4021 are connected through a third bus bar 405, and the plurality of fourth interdigital electrodes 4022 are connected through a fourth bus bar 406. Exemplarily, the third bus bar 405 and the fourth bus bar 406 are arranged in parallel, and both the third bus bar 405 and the fourth bus bar 406 extend along a direction perpendicular to the extending direction of the third interdigital electrodes 4021 or the fourth interdigital electrodes 4022. As Figure 11 shown, the third bus bar 405 and the fourth bus bar 406 extend along the 120° Y direction. Thus, the included angle between the third bus bar 405 and the first bus bar 403 or the included angle between the third bus bar 405 and the second bus bar 404 is also 90°, and the included angle between the fourth bus bar 406 and the first bus bar 403 or the included angle between the fourth bus bar 406 and the second bus bar 404 is also 90°.

[0112] The third bus bar 405 can be used as an input terminal, and the fourth bus bar 406 can be used as an output terminal. For example, an alternating voltage within a certain frequency range can be input to the plurality of third interdigital electrodes 4021 through the third bus bar 405, and an alternating voltage signal processed by the second resonator 320 can be output to the plurality of fourth interdigital electrodes 4022 through the fourth bus bar 406.

[0113] In an optional example, the second finger pitch P2 satisfies: Wherein: Vs is the shear body wave velocity of the substrate 10, and f2 is the operating frequency of the second resonator 320; wherein, the width of each third interdigital electrode 4021 is s3, the spacing between every two adjacent third interdigital electrodes 4021 and fourth interdigital electrodes 4022 is s4, and the second finger pitch P2 is the sum of the width s3 and the spacing s4. This can prevent energy from leaking towards the substrate 10 direction and improve the Q value and electromechanical coupling coefficient of the second resonator 320.

[0114] To prevent the parasitic resonance frequency positions generated by the first resonator 310 or the second resonator 320 from possibly approaching the main resonance frequency position, thereby affecting the in-band insertion loss performance and out-of-band rejection performance of the filter. Therefore, in an optional example, the first finger pitch and the second finger pitch are approximately equal.

[0115] In a specific example, the difference between the first finger pitch P1 and the second finger pitch P2 within 10% (including 10%) can be regarded as approximately equal. It can be understood that there are process tolerances for the width dimensions s1 of multiple first interdigital electrodes 4011, and there are also process tolerances for the spacing s2 between two adjacent first interdigital electrodes 4011 and the first interdigital electrode 4012. Similarly, there are process tolerances for the width dimensions s3 of multiple third interdigital electrodes 4021, and there are also process tolerances for the spacing s4 between two adjacent third interdigital electrodes 4021 and the fourth interdigital electrode 4022.

[0116] In a specific example, Figure 12 in (i) is the simulation curve obtained by using the structure defined in Table 1, Figure 12 in (ii) is the simulation curve obtained by using the structure defined in Table 2.

[0117]

[0118] Table 1

[0119]

[0120] Table 2

[0121] The thickness of the first piezoelectric layer 201 and the thickness of the first electrode 401 in the above Table 1 are the height dimensions of the first piezoelectric layer 201 and the height dimension of the first electrode 401 along the stacking direction of multiple film layer structures (such as Figure 10 the Y 1 direction). The thickness of the second piezoelectric layer 202 and the thickness of the second electrode 402 in the above Table 2 are the height dimensions of the second piezoelectric layer 202 and the height dimension of the second electrode 402 along the stacking direction of multiple film layer structures (such as Figure 10 the Y 1 direction).

[0122] The first occupation ratio in Table 1 above is the ratio between the width s1 of the first interdigital electrode and the first finger pitch P1, or the ratio between the width of the second interdigital electrode and the first finger pitch P1. In some examples, the width of the first interdigital electrode is equal to the width of the second interdigital electrode. The second occupation ratio in Table 2 above is the ratio between the width s3 of the third interdigital electrode and the second finger pitch P2, or the ratio between the width of the fourth interdigital electrode and the second finger pitch P2. In some examples, the width of the third interdigital electrode is equal to the width of the fourth interdigital electrode.

[0123] The electromechanical coupling coefficient K in Table 1 and Table 2 above t 2 can characterize the electromechanical coupling performance of the first resonator 310 and the second resonator 320. The larger the electromechanical coupling coefficient K t 2 is, the better the electromechanical coupling performance is.

[0124] In Figure 12 the admittance curves of the embodiments of the present application shown, the parasitic hybrid modes that appear near the resonance points of the SH1 main resonance mode are all outside the N79 frequency band and the 5G WIFI frequency band. Similarly, the parasitic hybrid modes that appear near the resonance points of the A1 main resonance mode are also all outside the N79 frequency band and the 5G WIFI frequency band. Therefore, the filter provided by the embodiments of the present application has good in-band insertion loss performance and out-of-band rejection performance.

[0125] In this embodiment, the first resonator 310 can use X-cut and a 30° Y propagation direction. The Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30°) to obtain the maximum K 34 2 so that the first-order horizontal shear mode SH1 mode of the first resonator 310 will be excited as the main resonance mode. The second resonator 320 can use X-cut and a 120° Y propagation direction. The Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120°) to obtain the maximum K 35 2 , so that the first-order anti-symmetry mode A1 mode of the second resonator 320 will be excited as the main resonance mode. At the same time, since the resonance modes of the first resonator and the second resonator are different, the sound velocities of the first piezoelectric layer 201 and the second piezoelectric layer 202 are also different, so that the frequencies of the first resonator and the second resonator are also different.

[0126] Exemplarily, the shear sound velocity Vt of the first piezoelectric layer 201 of the first resonator 310 is 4000 m / s. Therefore, the resonance frequency of the first resonator 310 is:

[0127]

[0128] Among them, Vt1 is the transverse shear sound velocity of the first piezoelectric layer, Vt2 is the longitudinal shear sound velocity of the first piezoelectric layer, and d LN is the thickness of the first piezoelectric layer 201.

[0129] The shear sound velocity Vt of the second piezoelectric layer 202 of the second resonator 320 is 4000 m / s, and the longitudinal wave sound velocity is 7000 m / s. Therefore, the resonance frequency of the second resonator 320 is:

[0130]

[0131] Thus, the first resonator 310 and the second resonator 320 in the filter provided by the embodiments of the present application can, under the condition of adopting the same geometric parameters, form a frequency difference between the first resonator 310 and the second resonator 320 by making the sound velocities of the first piezoelectric layer 201 and the second piezoelectric layer 202 different. Therefore, while ensuring the performance of the filter, the additional manufacturing procedures for forming the first resonator 310 and the second resonator 320 can be reduced, and the uniformity of the substrate 10 can be ensured, thereby improving the reliability of the filter.

[0132] Exemplarily, the geometric parameters include the thickness of the first piezoelectric layer 201, the thickness of the second piezoelectric layer 202, the thickness of the first electrode 401, the thickness of the second electrode 402, the thickness of the third electrode 501, the thickness of the fourth electrode 502, the first finger pitch, the second finger pitch, the first duty cycle, the second duty cycle, etc. It can be understood that the frequency difference between the first resonator 310 and the second resonator 320 can be adjusted by adjusting the geometric parameters of the first resonator 310 and the second resonator 320.

[0133] Refer to Figure 13 the shown dispersion curves, where Figure 13 in (i) is the dispersion curve when both the first piezoelectric layer 201 and the second piezoelectric layer 202 use X-cut and 30° Y propagation direction, Figure 13 in (ii) is the dispersion curve when both the first piezoelectric layer 201 and the second piezoelectric layer 202 use X-cut and 120° Y propagation direction, Figure 13 in (iii) is the dispersion curve when the first piezoelectric layer 201 uses X-cut and 30° Y propagation direction, and the second piezoelectric layer 202 uses X-cut and 120° Y propagation direction. As the first finger pitch and the second finger pitch change, the frequency difference between the first resonator 310 and the second resonator 320 also changes, and the first finger pitch and the second finger pitch can be set according to the required frequency difference.

[0134] In some other examples, the Euler angles of the crystal of the first piezoelectric material in the first piezoelectric layer 201 in this embodiment may also be (0°, 90°, 0° ± 30°), or it can be understood that the crystal cutting angle and the propagation direction of the first piezoelectric material are Y-cut and (0° ± 30°)X direction.

[0135] The "Y" in the above-mentioned Y-cut represents the Y direction of the first piezoelectric material. The Y-cut can be used to indicate that the Y-cut of the first piezoelectric material is in the same direction as the thickness direction of the first piezoelectric layer (such as Figure 9 the Y in 1 the direction), and the (0° ± 30°)X direction is in the same direction as the first direction.

[0136] The second piezoelectric layer 202 includes a second piezoelectric material. The Euler angles of the crystal of the second piezoelectric material are (0°, 90°, 90° ± 30°), or the crystal cutting angle and the propagation direction of the second piezoelectric material are Y-cut and (90° ± 30°)X direction.

[0137] The "Y" in the above-mentioned Y-cut represents the Y direction of the second piezoelectric material. The Y-cut can be used to indicate that the thickness direction of the second piezoelectric layer is in the same direction, and the (90° ± 30°)X direction of the second piezoelectric material is in the same direction as the second direction.

[0138] It can be understood that the above-mentioned "in the same direction" positioning allows for a certain error and can be close to the same direction. In one embodiment, the difference between the two angles within 5° (including 5°) can be regarded as close to the same direction.

[0139] Figure 14 The admittance curves of the first resonator 310 and the second resonator 320 in the embodiment of the present application are shown when the finger pitch is 1.08 - 1.14 um. When the finger pitch of the first resonator 310 and the second resonator 320 changes, the position of the corresponding main resonance mode resonance point also changes accordingly. In this embodiment, the first resonator 310 can use Y-cut and 0° ± 30°X propagation direction, and the Euler angles of the crystal of the first piezoelectric material are (0°, 90°, 0° ± 30°) to obtain the maximum K 34 2 Thus, the first-order horizontal shear mode SH1 mode of the first resonator 310 will be excited as the main resonance mode. The second resonator 320 can use Y-cut and 90° ± 30°X propagation direction, and the Euler angles of the crystal of the second piezoelectric material are (0°, 90°, 90° ± 30°) to obtain the maximum K 35 2 , so that the first-order antisymmetric mode A1 mode of the second resonator 320 will be excited as the main resonance mode. The electromechanical coupling coefficient K t 2 is 23%, and the electromechanical coupling coefficient K t 2can characterize the electromechanical coupling performance of the first resonator 310 and the second resonator 320, and the electromechanical coupling coefficient K t 2 The larger it is, the better the electromechanical coupling performance.

[0140] According to Figure 14 It can be seen that in this embodiment, the parasitic hybrid modes that appear near the resonance points of the SH1 main resonance mode are all outside the N79 frequency band and the 5G WIFI frequency band. Similarly, the parasitic hybrid modes that appear near the resonance points of the A1 main resonance mode are also all outside the N79 frequency band and the 5G WIFI frequency band. Therefore, the filter provided by the embodiment of the present application has good in-band insertion loss performance and out-of-band rejection performance.

[0141] It can be understood that the foregoing embodiments and the beneficial effects brought about are equally applicable to this embodiment. Therefore, the same parts will not be described again.

[0142] In an alternative embodiment, refer to Figure 15 and Figure 16 which show the process structure diagrams of two different structures of filters. In Figure 15 , cavities 105 are provided in both the first region 101 and the second region 102 of the substrate 10. Such first resonator 310 and second resonator 320 can be referred to as cavity 105 type suspended piezoelectric thin film resonators; in Figure 16 , compared with Figure 15 , Figure 16 the first region 101 and the second region 102 of the substrate 10 in Figure 15 are solid structures without cavities 105, and, compared with Figure 16 other layer structures can be stacked between the first electrode 401 and the first region 101 of the substrate 10 and between the second electrode 402 and the second region 102 of the substrate 10. For example, a first dielectric layer 601 or other functional layer structures can be stacked between the substrate 10 and the first electrode 401.

[0143] Or, it can be understood as the structures shown in Figure 15 and Figure 16 . Taking the first resonator 310 as an example, the first electrode 401 has opposite (which can also be referred to as facing away from or opposite) first and second surfaces, and the first surface is closer to the first piezoelectric layer 201 than the second surface; in Figure 15 the cavity 105 type suspended piezoelectric thin film resonator of Figure 16In the solid-state substrate 10 piezoelectric thin-film resonator, the first electrode 401 is disposed between the first dielectric layer 601 and the first piezoelectric layer 201, and the second surface of the first electrode 401 is in contact with the first dielectric layer 601. For example, in Figure 16 if the first dielectric layer 601 is not provided, the first electrode 401 is disposed between the substrate 10 and the first piezoelectric layer 201, and the second surface of the first electrode 401 is in contact with the substrate 10.

[0144] In the resonator provided by the above embodiment, the substrate 10 can be a high sound velocity substrate 10. For example, it can be any one of silicon carbide (SiC), diamond, boron nitride (BN), or a combination of multiple ones.

[0145] The material of the first piezoelectric layer 201 includes at least one of a combination of niobium, lithium, and oxygen, a combination of tantalum, lithium, and oxygen. For example, the material of the first piezoelectric layer 201 includes lithium tantalate (LiTaO 3 ), lithium niobate (LiNbO 3 ), aluminum nitride (AlN), zinc oxide (ZnO), any one of them, or a combination of multiple ones.

[0146] The first electrode 401 can be any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.), or a conductive metal with a high acoustic impedance (including but not limited to W, Ru, Mo, Pt, etc.). These metals with a high acoustic impedance help increase the electromechanical coupling coefficient and improve the quality factor Q, further enhancing the performance of the resonator.

[0147] The third electrode 501 can be any possible conductive metal (including but not limited to Al, Cu, W, Mo, Ru, Pt, etc.). The first electrode 401 and the third electrode 501 can be the same conductive metal or different conductive metals.

[0148] To increase the connection strength between the third electrode 501 and the first dielectric layer 601, as Figure 17 , a conductive connection layer 60a can be stacked between the first dielectric layer 601 and the third electrode 501.

[0149] Or, in some other examples, to increase the connection strength between the first piezoelectric layer 201 and the third electrode 501, continue to refer to Figure 17 , a conductive connection layer 60b can be stacked between the first piezoelectric layer 201 and the third electrode 501.

[0150] The above Figure 17The conductive connection layer 60a and the conductive connection layer 60b can be made of the same material or different materials. For example, any possible conductive metal can be selected (including but not limited to Ti, Cr, etc.). In some examples, the bonding strength of the conductive connection layer can be selected from 10 MPa to 40 GPa. For example, it can be 1.5 GPa.

[0151] Figure 18 is another process structure diagram of a filter given in the embodiments of the present application. In Figure 18 , a Bragg reflection structure 701 is formed on the first region 101 of the substrate 10, the third electrode 501 is disposed on the side of the Bragg reflection structure 701 away from the substrate 10, the first piezoelectric layer 201 is stacked between the first electrode 401 and the third electrode 501, and conductive connection layers (60a, 60b) are stacked between the first piezoelectric layer 201 and the third electrode 501, and between the third electrode 501 and the Bragg reflection structure.

[0152] Among them, the Bragg reflection structure 701 includes a multilayer stacked film layer structure, which is formed by alternately stacking a high acoustic impedance material and a low acoustic impedance material. The high acoustic impedance materials include but are not limited to: tungsten (W), hafnium oxide (HfO 2 ), molybdenum (Mo), etc.; the low acoustic impedance materials include but are not limited to: silicon oxide (SiO 2 ), etc. These alternating stacked structures form a Bragg reflection effect on the acoustic waves that may propagate downward, suppress the downward leakage of energy, and improve the Q value and electromechanical coupling coefficient of the resonator.

[0153] For example, the Bragg reflection structure 701 includes a stacked first reflection layer and a second reflection layer. Among them, the thickness t1 of the first reflection layer satisfies: The thickness t2 of the second reflection layer satisfies: λ 1 is the wavelength of the acoustic wave in the material of the first reflection layer of the first resonator 310 at the resonant frequency, and λ 2 is the wavelength of the acoustic wave in the material of the second reflection layer.

[0154] In some examples, In some other examples, In still some other examples, λ 1 ;

[0155] If the first reflection layer and the second reflection layer are divided into a group, in some examples, the Bragg reflection structure 701 can include three groups, or more groups, for example, ten groups.

[0156] It should be understood that the above examples are only examples listed for better understanding the technical solutions of the embodiments of the present invention and do not serve as the sole limitation to the embodiments of the present invention. A Bragg reflection structure 701 may also be provided in the second resonator 320. For related parts, reference may be made to the first resonator 310 in the above embodiments, which will not be elaborated in this application.

[0157] Figure 19 is a process structure diagram of another filter given by the embodiments of the present application. Compared with the above Figures 15 to 18 In this embodiment, a passivation layer 702 is further included. The surfaces of the first resonator 310 and the second resonator 320 away from the substrate 10 can be covered by the passivation layer 702. The passivation layer 702 can be used to protect the first resonator and the second resonator from potential corrosion, scratching, oxidation, etc.

[0158] The passivation layer 702 can be made of a dielectric material. For example, it can be made of silicon oxide, silicon nitride, etc.

[0159] In addition, the passivation layer 702 can also adjust the electromechanical coupling coefficient and temperature coefficient (Temperature coefficient of frequency, TCF) of the first resonator 310 and the second resonator 320, etc., so as to further optimize the filtering performance of the device. At the same time, the frequency difference between the first resonator 310 and the second resonator 320 can be further adjusted by adjusting the thickness of the passivation layer 702.

[0160] Furthermore, the cavity-type suspended piezoelectric thin-film resonator or the solid-substrate piezoelectric thin-film resonator involved above can be electrically connected in a trapezoidal structure as Figure 20 shown to realize a filter for radio frequency communication. In the filter, there can be resonators connected in series with each other or resonators connected in parallel with each other. Among them, the first resonator 310 in the above embodiments can be a parallel resonator, and the second resonator 320 is a series resonator. The resonance frequency of the parallel resonator can be lower than that of the series resonator. For example, a thicker piezoelectric layer or a thicker passivation layer or a larger finger pitch P in the above resonator process structure can reduce the resonance frequency of the resonator.

[0161] Figure 20In the example, the filter includes second resonators 301, 302, and 303, first resonators 304 and 305. The second resonators 301, 302, and 303 are series resonators, and the first resonators 304 and 305 are parallel resonators. At least one of the first and second resonators among the second resonators 301, 302, 303, first resonators 304 and 305 can be the first and second resonators involved in the above embodiments.

[0162] In some examples, such as Figure 21 , Figure 21 shows Figure 20 the relationship between the admittance curves of the respective resonators of the ladder filter and the transmission loss curve of the filter in Figure 21 . For the series resonators (such as the second resonators 301, 302, and 303) and parallel resonators (such as the first resonators 304 and 305), the resonance points of the series resonators and the anti-resonance points of the parallel resonators are located within the passband frequency band, forming the passband of the filter. The anti-resonance points of the series resonators (such as the second resonators 301, 302, and 303) are located on the high-frequency side outside the passband, and the resonance points of the parallel resonators (such as the first resonators 304 and 305) are located on the low-frequency side outside the passband. Thus, the filter features high roll-off and high out-of-band rejection.

[0163] In the filter, in the process structures that can be implemented, multiple resonators provided in the embodiments of the present application can be integrated on the same substrate 10. For example, as Figure 22 , the serially connected second resonators 301, 302, and 303 are integrated on the substrate 10. The second resonator 301 and the second resonator 302 are electrically connected through a conductive connection layer 130, and the second resonator 302 and the second resonator 303 are electrically connected through a conductive connection layer 140. It can be understood that the conductive connection layer 130 or the conductive connection layer 140 has various implementable structures.

[0164] The filter involved in the above embodiments of the present application can also be applied in a duplexer or a multiplexer. In the duplexer, it includes a transmit channel filter and a receive channel filter. At least one of the transmit channel filter and the receive channel filter can use the above filter for filtering. In the multiplexer, it includes multiple transmit channel filters and multiple receive channel filters. Among them, at least one of the multiple transmit channel filters or at least one of the multiple receive channel filters can use the filter involved in the embodiments of the present application.

[0165] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0166] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. A filter, characterized in that, comprising: a substrate; a first resonator and a second resonator disposed on the substrate; wherein, the first resonator includes a first region of the substrate and a first piezoelectric layer disposed on the first region of the substrate, and a plurality of first electrodes are arranged side by side on the first piezoelectric layer along a first direction; the second resonator includes a second region of the substrate and a second piezoelectric layer disposed on the second region of the substrate; a plurality of second electrodes are arranged side by side on the second piezoelectric layer along the second direction; the first direction and the second direction differ by 70° - 110°.

2. The filter according to claim 1, characterized in that, the first piezoelectric layer includes a first piezoelectric material, and the Euler angles of the crystal of the first piezoelectric material are (90°, 90°, 30° ± 30°), or the crystal cutting angle of the first piezoelectric material and the propagation direction of the first resonator are X-cut, (30° ± 30°)Y direction, wherein the X direction of the first piezoelectric material is in the same direction as the thickness direction of the first piezoelectric layer, and the (30° ± 30°)Y direction of the first piezoelectric material is in the same direction as the first direction; the second piezoelectric layer includes a second piezoelectric material, and the Euler angles of the crystal of the second piezoelectric material are (90°, 90°, 120° ± 30°), or the crystal cutting angle of the second piezoelectric material and the propagation direction of the first resonator are X-cut, (120° ± 30°)Y direction, wherein the X-cut of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer, and the (120° ± 30°)Y direction of the second piezoelectric material is in the same direction as the second direction.

3. The filter according to claim 1, characterized in that, the first piezoelectric layer includes a first piezoelectric material, and the Euler angles of the crystal of the first piezoelectric material are (0°, 90°, 0° ± 30°), or the crystal cutting angle of the first piezoelectric material and the propagation direction are Y-cut, (0° ± 30°)X direction, wherein the Y-cut direction of the first piezoelectric material is in the same direction as the thickness direction of the first piezoelectric layer, and the (0° ± 30°)X direction of the first piezoelectric material is in the same direction as the first direction; the second piezoelectric layer includes a second piezoelectric material, and the Euler angles of the crystal of the second piezoelectric material are (0°, 90°, 90° ± 30°), or the crystal cutting angle of the second piezoelectric material and the propagation direction are Y-cut, (90° ± 30°)X direction, wherein the Y-cut of the second piezoelectric material is in the same direction as the thickness direction of the second piezoelectric layer, and the (90° ± 30°)X direction of the second piezoelectric material is in the same direction as the second direction.

4. The filter according to any one of claims 1 - 3, characterized in that, the first resonator further includes: a third electrode, and the third electrode is disposed between the first region of the substrate and the first piezoelectric layer.

5. The filter according to any one of claims 1 - 4, characterized in that, the second resonator further includes: a fourth electrode, and the fourth electrode is disposed between the second region of the substrate and the second piezoelectric layer.

6. The filter according to any one of claims 1-5, characterized in that, the thicknesses of the first piezoelectric layer and the second piezoelectric layer are equal.

7. The filter according to any one of claims 1-6, characterized in that, the first resonator further comprises: a first bus bar and a second bus bar; one of every two adjacent first electrodes among the plurality of first electrodes is a first interdigital electrode, and the other is a second interdigital electrode; the first interdigital electrode and the second interdigital electrode are spaced apart in the first direction; the plurality of first interdigital electrodes among the plurality of first electrodes are connected by the first bus bar, and the plurality of second interdigital electrodes among the plurality of first electrodes are connected by the second bus bar.

8. The filter according to claim 7, characterized in that, the second resonator further comprises: a third bus bar and a fourth bus bar; one of every two adjacent second electrodes among the plurality of second electrodes is a third interdigital electrode, and the other is a fourth interdigital electrode; the third interdigital electrode and the fourth interdigital electrode are spaced apart in the second direction; the plurality of third interdigital electrodes among the plurality of second electrodes are connected by the third bus bar, and the plurality of fourth interdigital electrodes among the plurality of second electrodes are connected by the fourth bus bar.

9. The filter according to claim 8, characterized in that, the third electrode has opposite first and second surfaces, the first surface is located on a side close to the first piezoelectric layer, and the second surface of the third electrode is attached to a first portion of the substrate.

10. The filter according to claim 9, characterized in that, The first finger pitch P1 satisfies: where: Vs is the shear body wave velocity of the substrate, and f1 is the operating frequency of the first resonator; wherein, the width dimension of each first interdigital electrode is s1, the spacing between every two adjacent first interdigital electrodes and second interdigital electrodes is s2, and the first finger bar pitch P1 = s1 + s2.

11. The filter according to claim 10, characterized in that, the second finger bar pitch P2 is approximately equal to the first finger bar pitch P1, wherein, the width dimension of each third interdigital electrode is s3, the spacing between every two adjacent third interdigital electrodes and fourth interdigital electrodes is s4, and the second finger bar pitch P2 = s3 + s4.

12. The filter according to claim 4, characterized in that, the third electrode has opposite first and second surfaces, the first surface is located on a side close to the first piezoelectric layer; a cavity is provided in a first region of the substrate, at least a part of the second surface of the third electrode is used to enclose the cavity, and at least a part of the third electrode is disposed between the cavity and the first piezoelectric layer.

13. The filter according to claim 4, characterized in that, the first resonator further comprises: a stacked first reflective layer and a second reflective layer; the first reflective layer and the second reflective layer are disposed between a first region of the substrate and the third electrode.

14. The filter according to claim 4, characterized in that, The first resonator further includes: a first dielectric layer disposed between a first region of the substrate and the third electrode.

15. The filter according to any one of claims 1-14, wherein, the material of the first piezoelectric layer includes at least one combination of a combination of niobium, lithium and oxygen, a combination of tantalum, lithium and oxygen.

16. The filter according to any one of claims 1-15, wherein, the filter further includes a passivation layer covering the first resonator and the second resonator.

17. An electronic device, wherein, comprising: a control circuit; a filter according to any one of claims 1-16, the filter being electrically connected to the control circuit.

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