Surface acoustic wave resonator, filter, radio frequency front-end module and electronic device

Abstract

The present application belongs to the technical field of resonators. Provided are a surface acoustic wave resonator, a filter, a radio frequency front-end module and an electronic device. The surface acoustic wave resonator comprises an interdigital transducer, the interdigital transducer comprising a first bus bar, a second bus bar, a plurality of first electrode fingers, and a plurality of second electrode fingers. A first dielectric block is provided between each first electrode finger and the second bus bar, the first dielectric block being separately and fixedly connected to the first electrode finger and the second bus bar. A second dielectric block is provided between each second electrode finger and the first bus bar, the second dielectric block being separately and fixedly connected to the second electrode finger and the first bus bar. The first dielectric blocks reduce the vibration amplitude of the first electrode fingers, and the second dielectric blocks reduce the vibration amplitude of the second electrode fingers. Thus, reducing the vibration amplitude of the first electrode fingers and the vibration amplitude of the second electrode fingers can suppress the shear horizontal (SH) mode and coupled modes of the surface acoustic wave resonator.

Description

Surface acoustic wave resonators, filters, RF front-end modules and electronic equipment

[0001] This application claims priority to Chinese Patent Application No. 202411934370.2, filed on December 25, 2024, entitled “Surface Acoustic Wave Resonator, Filter, RF Front-End Module and Electronic Equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of resonator technology, and in particular to a surface acoustic wave resonator, filter, radio frequency front-end module and electronic device. Background Technology

[0003] Surface acoustic wave (SAW) resonators utilize the characteristics of acoustic-electric transducers to process acoustic signals propagating on the surface of a piezoelectric layer. Filters composed of SAW resonators have advantages such as low cost, small size, and multiple functions, and therefore have been widely used in radar, communication, navigation, signal recognition, and other fields.

[0004] The two main vibration modes of surface acoustic waves (SAWs) are Rayleigh modes and shear horizontal (SH) modes. In existing technologies, SAW resonators exhibit not only Rayleigh and SH modes but also extraneous modes. These extraneous modes affect the passband characteristics of the resonator, and consequently, the performance of the filter. Summary of the Invention

[0005] This application provides a surface acoustic wave resonator, a filter, an RF front-end module, and an electronic device, which aims to suppress stray modes in the vibration modes of the surface acoustic wave resonator and ensure the performance of the filter.

[0006] In a first aspect, embodiments of this application provide a surface acoustic wave (SAW) resonator, which includes a piezoelectric layer and an interdigital transducer, the interdigital transducer being disposed on a surface of the piezoelectric layer. The interdigital transducer includes a first busbar, a second busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers. The first busbar and the second busbar are arranged along a first direction and spaced apart. The plurality of first electrode fingers are connected to the first busbar and extend towards the second busbar, spaced apart from the second busbar. The plurality of second electrode fingers are connected to the second busbar and extend towards the first busbar, spaced apart from the first busbar. The plurality of first electrode fingers and the plurality of second electrode fingers are arranged alternately and spaced apart along a second direction, the second direction being perpendicular to the first direction.

[0007] The interdigital transducer further includes multiple first dielectric blocks and multiple second dielectric blocks. The first dielectric blocks are disposed at the end of the first electrode finger opposite to the end of the first busbar and extend to the second busbar, and are fixedly connected to both the first electrode finger and the second busbar. The second dielectric blocks are disposed at the end of the second electrode finger opposite to the end of the second busbar and extend to the first busbar, and are fixedly connected to both the second electrode finger and the first busbar.

[0008] In existing technologies, due to the structure of interdigital transducers, the vibration amplitude of the electrode fingers is greatest at the tip, generating SH transverse mode vibration. As surface acoustic wave (SAW) resonators become smaller, the density of the electrode fingers increases, leading to a decrease in the sound velocity difference between the Rayleigh mode and the SH mode. This results in the coupling of the Rayleigh mode and the SH mode, forming a coupled mode. Both the SH transverse mode and the coupled mode affect the passband of the resonator. The first dielectric block reduces the vibration amplitude of the first electrode finger in the second direction, and the second dielectric block reduces the vibration amplitude of the second electrode finger in the second direction. By reducing the vibration amplitude of both the first and second electrode fingers in the second direction, the SH transverse mode and the coupled mode in the vibration modes of the SAW resonator can be suppressed, improving the passband characteristics of the resonator.

[0009] In an exemplary embodiment, the first dielectric block includes a first dielectric body, which is fixedly connected between the first electrode finger and the second busbar, and is also connected to a piezoelectric layer. The second dielectric block includes a second dielectric body, which is fixedly connected between the second electrode finger and the first busbar, and is also connected to a piezoelectric layer. The first dielectric body reduces the vibration amplitude of the first electrode finger in a second direction and reduces the vibration amplitude of the first electrode finger in a third direction. The second dielectric body reduces the vibration amplitude of the second electrode finger in a second direction and reduces the vibration amplitude of the second electrode finger in a third direction.

[0010] In an exemplary embodiment, the first dielectric body has a dimension of 0.15 μm to 3 μm along the first direction, and the second dielectric body has a dimension of 0.15 μm to 3 μm along the first direction. Due to process limitations, the dimension of the first dielectric body along the first direction will not be less than 0.15 μm. Due to process limitations, the dimension of the second dielectric body along the first direction will not be less than 0.15 μm.

[0011] In an exemplary embodiment, the first dielectric block further includes a first connector disposed on the surface of the first dielectric body facing away from the piezoelectric layer, and the first connector is fixedly connected to the first dielectric body, the first electrode finger, and the second busbar. The second dielectric block further includes a second connector disposed on the surface of the second dielectric body facing away from the piezoelectric layer, and the second connector is fixedly connected to the second dielectric body, the second electrode finger, and the first busbar. The first connector reduces the vibration amplitude of the first electrode finger in the second direction and reduces the vibration amplitude of the first electrode finger in the third direction. The second connector reduces the vibration amplitude of the second electrode finger in the second direction and reduces the vibration amplitude of the second electrode finger in the third direction.

[0012] In an exemplary embodiment, the first connector has a dimension of 0.45 μm to 24 μm along the first direction, and the dimension of the first connector along the first direction is larger than the dimension of the first dielectric body along the first direction, so that the first connector can be fixedly connected to the first electrode finger and the second busbar. The second connector has a dimension of 0.45 μm to 24 μm along the first direction, and the dimension of the second connector along the first direction is larger than the dimension of the second dielectric body along the first direction, so that the second connector can be fixedly connected to the second electrode finger and the first busbar.

[0013] In an exemplary embodiment, the dimension of the first connector along a third direction is 50 to 500 nm, and the dimension of the second connector along the third direction is also 50 to 500 nm. The third direction is perpendicular to both the first and second directions, and is the thickness direction of the interdigital transducer. The larger the dimension of the first connector along the third direction, the greater the vibration amplitude of the first electrode finger lowered by the first dielectric block in the second direction. Similarly, the larger the dimension of the second connector along the third direction, the greater the vibration amplitude of the first electrode finger lowered by the second dielectric block in the second direction.

[0014] In an exemplary embodiment, the first dielectric block further includes a first insert and a second insert. The first insert and the second insert are fixedly connected to the surface of the first connector facing the first dielectric body. The first insert and the second insert are located on opposite sides of the first dielectric body along the first direction, and are spaced apart from the first dielectric body. The first insert is embedded in the first electrode finger, and the second insert is embedded in the second busbar. The first insert increases the connection strength between the first dielectric block and the first electrode finger, and the second insert increases the connection strength between the first dielectric block and the second busbar.

[0015] The second dielectric block further includes a third embedding and a fourth embedding. The third and fourth embeddings are fixedly connected to the surface of the second connector facing the second dielectric body. The third and fourth embeddings are located on opposite sides of the second dielectric body along the first direction, and are spaced apart from the second dielectric body. The third embedding is embedded in the second electrode finger, and the fourth embedding is embedded in the first busbar. The third embedding increases the connection strength between the second dielectric block and the second electrode finger, and the fourth embedding increases the connection strength between the second dielectric block and the first busbar.

[0016] In an exemplary embodiment, the dimensions of the first and second embeddings along the first direction are both 0.15 μm to 3 μm. The dimensions of the third and fourth embeddings along the second direction are both 0.15 μm to 3 μm. Due to process limitations, the dimensions of the first and second embeddings along the first direction will not be less than 0.15 μm. Due to process limitations, the dimensions of the third and fourth embeddings along the first direction will not be less than 0.15 μm.

[0017] In one possible implementation, the plurality of first medium blocks are spaced apart from each other, and the plurality of second medium blocks are spaced apart from each other, which helps to save materials.

[0018] In another possible implementation, multiple first dielectric blocks are sequentially connected along the second direction, which facilitates the fabrication process of forming the first dielectric blocks. Similarly, multiple second dielectric blocks are sequentially connected along the second direction, which facilitates the fabrication process of forming the second dielectric blocks.

[0019] In one possible implementation, the interdigital transducer further includes a third busbar and a fourth busbar. The third busbar is disposed on the side of the first busbar opposite to the second busbar and is spaced apart from the first busbar. The fourth busbar is disposed on the side of the second busbar opposite to the first busbar and is spaced apart from the second busbar. The interdigital transducer also includes a plurality of first connecting fingers and a plurality of second connecting fingers. The first connecting fingers are fixedly connected between the first busbar and the third busbar, and the second connecting fingers are fixedly connected between the second busbar and the fourth busbar.

[0020] The first connecting finger and the third bus bar are used to form high and low sound speed zones to reflect the energy propagating to the high and low sound speed zones. The second connecting finger and the fourth bus bar are used to form high and low sound speed zones to reflect the energy propagating to the high and low sound speed zones, thereby improving the performance of the filter.

[0021] Secondly, embodiments of this application also provide a surface acoustic wave (SAW) resonator, which includes a piezoelectric layer and an interdigital transducer, wherein the interdigital transducer is disposed on a surface of the piezoelectric layer. The interdigital transducer includes a first busbar, a second busbar, a plurality of first electrode fingers, a plurality of second electrode fingers, a plurality of first dummy fingers, and a plurality of second dummy fingers. The first busbar and the second busbar are arranged along a first direction and spaced apart. The plurality of first electrode fingers are connected to the first busbar and extend towards the second busbar, spaced apart from the second busbar. The plurality of second electrode fingers are connected to the second busbar and extend towards the first busbar, spaced apart from the first busbar. The plurality of first electrode fingers and the plurality of second electrode fingers are arranged alternately and spaced apart along a second direction, which is perpendicular to the first direction.

[0022] The first spur finger is disposed at the end of the first electrode finger facing away from the first bus bar, the first spur finger is spaced apart from the first electrode finger, and the first spur finger is connected to the second bus bar. The second spur finger is disposed at the end of the second electrode finger facing away from the second bus bar, the second spur finger is spaced apart from the second electrode finger, and the second spur finger is connected to the first bus bar.

[0023] The interdigital transducer further includes multiple first dielectric blocks and multiple second dielectric blocks. The first dielectric blocks are disposed at the end of the first electrode finger opposite to the first busbar and extend to the first dummy finger. The first dielectric blocks are fixedly connected to both the first electrode finger and the first dummy finger. The second dielectric blocks are disposed at the end of the second electrode finger opposite to the second busbar and extend to the second dummy finger. The second dielectric blocks are fixedly connected to both the second electrode finger and the second dummy finger.

[0024] In existing technologies, due to the structure of interdigital transducers, the vibration amplitude of the electrode fingers is greatest at the tip, generating SH transverse mode vibration. As surface acoustic wave (SAW) resonators become smaller, the density of the electrode fingers increases, leading to a decrease in the sound velocity difference between the Rayleigh mode and the SH mode. This results in the coupling of the Rayleigh mode and the SH mode, forming a coupled mode. Both the SH transverse mode and the coupled mode affect the passband of the resonator. The first dielectric block reduces the vibration amplitude of the first electrode finger in the second direction, and the second dielectric block reduces the vibration amplitude of the second electrode finger in the second direction. By reducing the vibration amplitude of both the first and second electrode fingers in the second direction, the SH transverse mode and the coupled mode in the vibration modes of the SAW resonator can be suppressed, improving the passband characteristics of the resonator.

[0025] In an exemplary embodiment, the first dielectric block includes a first dielectric body, which is fixedly connected between the first electrode finger and the first dummy finger, and is also connected to a piezoelectric layer. The second dielectric block includes a second dielectric body, which is fixedly connected between the second electrode finger and the second dummy finger, and is also connected to a piezoelectric layer. The first dielectric body reduces the vibration amplitude of the first electrode finger in a second direction and reduces the vibration amplitude of the first electrode finger in a third direction. The second dielectric body reduces the vibration amplitude of the second electrode finger in a second direction and reduces the vibration amplitude of the second electrode finger in a third direction.

[0026] In an exemplary embodiment, the first dielectric block further includes a first connector disposed on the surface of the first dielectric body opposite to the piezoelectric layer, and the first connector is fixedly connected to the first dielectric body, the first electrode finger, and the first dummy finger. The second dielectric block further includes a second connector disposed on the surface of the second dielectric body opposite to the piezoelectric layer, and the second connector is fixedly connected to the second dielectric body, the second electrode finger, and the second dummy finger. The first connector reduces the vibration amplitude of the first electrode finger in a second direction and reduces the vibration amplitude of the first electrode finger in a third direction. The second connector reduces the vibration amplitude of the second electrode finger in a second direction and reduces the vibration amplitude of the second electrode finger in a third direction.

[0027] In an exemplary embodiment, the first dielectric block further includes a first insert and a second insert. The first insert and the second insert are fixedly connected to the surface of the first connector facing the first dielectric body. The first insert and the second insert are located on opposite sides of the first dielectric body along the first direction, and are spaced apart from the first dielectric body. The first insert is embedded in the first electrode finger, and the second insert is embedded in the first dummy finger. The first insert increases the connection strength between the first dielectric block and the first electrode finger, and the second insert increases the connection strength between the first dielectric block and the second busbar.

[0028] The second dielectric block further includes a third embedding and a fourth embedding. The third and fourth embeddings are fixedly connected to the surface of the second connector facing the second dielectric body. The third and fourth embeddings are located on opposite sides of the second dielectric body along the first direction, and are spaced apart from the second dielectric body. The third embedding is embedded in the second electrode finger, and the fourth embedding is embedded in the second pseudo-finger. The third embedding increases the connection strength between the second dielectric block and the second electrode finger, and the fourth embedding increases the connection strength between the second dielectric block and the first busbar.

[0029] Thirdly, embodiments of this application also provide a filter, the filter including a plurality of the above-described surface acoustic wave resonators, the plurality of surface acoustic wave resonators being electrically connected.

[0030] Fourthly, embodiments of this application also provide a radio frequency front-end module, which includes an amplifier and the aforementioned filter, wherein the amplifier and the filter are electrically connected.

[0031] Fifthly, embodiments of this application also provide an electronic device, which includes a housing and the aforementioned radio frequency front-end module, wherein the radio frequency front-end module is disposed within the housing. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0033] Figure 1 is a schematic diagram of the structure of the electronic device disclosed in an embodiment of this application;

[0034] Figure 2 is a schematic diagram of the circuit structure of the filter disclosed in an embodiment of this application;

[0035] Figure 3 is a top view of the filter structure disclosed in the embodiment of this application;

[0036] Figure 4 is a schematic diagram of the first type of cross-section of the filter shown in Figure 3 along direction II;

[0037] Figure 5 is a schematic diagram of the second cross-section of the filter shown in Figure 3 along direction II;

[0038] Figure 6 is a schematic diagram of the first structure of the interdigital transducer disclosed in the embodiment of this application;

[0039] Figure 7 is a schematic diagram of the vibration modes of surface acoustic waves;

[0040] Figure 8 shows the admittance characteristic curve of the resonator in the prior art;

[0041] Figure 9 is a schematic diagram of the admittance characteristic curve of the surface acoustic wave resonator disclosed in the embodiment of this application;

[0042] Figure 10 is a schematic diagram of the busbar and electrode fingers shown in Figure 6;

[0043] Figure 11 is a schematic cross-sectional view of the interdigital transducer shown in Figure 6 along the II-II direction;

[0044] Figure 12 is a schematic cross-sectional view of the interdigital transducer shown in Figure 6 along the III-III direction;

[0045] Figure 13 is a schematic diagram of the second structure of the interdigital transducer disclosed in the embodiment of this application;

[0046] Figure 14 is a schematic diagram of the third structure of the interdigital transducer disclosed in the embodiments of this application;

[0047] Figure 15 is a schematic diagram of the fourth structure of the interdigital transducer disclosed in the embodiments of this application;

[0048] Figure 16 is a schematic diagram of the busbar and electrode fingers shown in Figure 15;

[0049] Figure 17 is a schematic cross-sectional view of the interdigital transducer shown in Figure 15 along the IV-IV direction;

[0050] Figure 18 is a cross-sectional view of the interdigital transducer shown in Figure 15 along the VV direction.

[0051] Figure 19 is a schematic diagram of the fifth structure of the interdigital transducer disclosed in the embodiments of this application;

[0052] Figure 20 is a schematic diagram of the sixth structure of the interdigital transducer disclosed in the embodiments of this application. Detailed Implementation

[0053] In the description of the embodiments of this application, it is understood that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after the connection.

[0054] The directional terms mentioned in the embodiments of this application, such as "upper", "lower", "top", "bottom", "inner", "outer", "side", etc., are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0055] In the embodiments of this application, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," "third," and "fourth" may explicitly or implicitly include one or more of that feature. The term "multiple" refers to at least two.

[0056] In the embodiments of this application, the terms "parallel," "perpendicular," and "aligned" are used in relation to the current technological level, rather than being absolutely strict mathematical definitions. Slight deviations are permissible; approximations of parallelism, perpendicularity, and alignment are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, with the angle between A and B ranging from 0° to 10°. Similarly, "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, with the angle between A and B ranging from 80° to 100°. Finally, "A and B are aligned" means that A and B are aligned or approximately aligned, with the alignment difference between A and B within 1 nm.

[0057] References to "some embodiments" and the like in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "some embodiments," "in other embodiments," and "in still other embodiments" appearing in different parts of this specification do not necessarily refer to the same embodiments, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically emphasized.

[0058] It is understood that the specific embodiments described herein are merely illustrative of related embodiments and not intended to limit the scope of those embodiments. It is also understood that, for ease of description, the accompanying drawings show only the parts relevant to the embodiments.

[0059] It is understood that, without conflict, the embodiments and features described in this application can be combined with each other.

[0060] The embodiments of this application are described below with reference to the accompanying drawings.

[0061] This application provides an electronic device. Please refer to Figure 1, which is a schematic diagram of the structure of the electronic device disclosed in this application. The electronic device 1 in this application can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, smart wearable device (e.g., smartwatch, smart bracelet, smart glasses), virtual reality (VR) terminal device, augmented reality (AR) terminal device, smart TV, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical care, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. The embodiments of this application do not limit the application scenarios.

[0062] The electronic device 1 includes an antenna 10, a radio frequency (RF) front-end module 20, and a modulator 30. The RF front-end module 20 is electrically connected to both the antenna 10 and the modulator 30. The antenna 10 and the RF front-end module 20 transmit RF signals to each other, and the RF front-end module 20 and the modulator 30 transmit RF signals to each other.

[0063] Antenna 10 is used to transmit received radio frequency (RF) signals as electromagnetic waves and to convert received electromagnetic waves into RF signals. RF front-end module 20 amplifies and filters the RF signals. Modulator 30 converts baseband signals into RF signals and vice versa.

[0064] When electronic device 1 needs to send data, modulator 30 processes the baseband signal to be transmitted into a radio frequency (RF) signal and outputs the RF signal to RF front-end module 20. RF front-end module 20 then processes the RF signal and transmits it outward as an electromagnetic wave through antenna 10. When data is sent to electronic device 1, RF front-end module 20 receives the RF signal through antenna 10 and outputs the processed RF signal to modulator 30.

[0065] Electronic device 1 may include a processor, a memory, and input / output devices. The processor is primarily used to process communication protocols and data, control electronic device 1, execute software programs, and process data from those programs. The memory is primarily used to store software programs and data. The input / output devices are used to receive user input and output data to the user; these devices may be touchscreens, displays, keyboards, etc.

[0066] The electronic device 1 may also include a housing, in which the antenna 10, the radio frequency front-end module 20 and the modulator 30 are all disposed, and the housing is used to protect the antenna 10, the radio frequency front-end module 20 and the modulator 30.

[0067] Based on this, this application embodiment also provides a radio frequency (RF) front-end module 20, which includes at least one RF circuit 21 and an antenna switch module 22. Each RF circuit 21 is electrically connected to a modulator 30 and an antenna switch module 22, respectively. The RF circuit 21 is used to process RF signals, and the antenna switch module 22 is used to connect or disconnect the RF circuit 21 from the antenna 10. When the RF circuit 21 is connected to the antenna 10, RF signals can be transmitted between them. When the RF circuit 21 is disconnected from the antenna 10, RF signals cannot be transmitted between them. The arrows in Figure 1 indicate the direction of RF signal transmission.

[0068] Each RF circuit 21 includes a first amplifier 51, a second amplifier 52, a switch 53, and a filter 100. The first amplifier 51 is electrically connected to both the modulator 30 and the filter 100. The filter 100 is also electrically connected to both the switch 53 and the antenna switch module 22. The second amplifier 52 is electrically connected to both the modulator 30 and the switch 53. Both the first amplifier 51 and the second amplifier 52 amplify the RF signal. The switch 53 is used to connect or disconnect the second amplifier 52 and the filter 100. When the second amplifier 52 is connected to the filter 100, RF signals can be transmitted between them. When the second amplifier 52 is disconnected from the filter 100, RF signals cannot be transmitted between them. The filter 100 is used to filter the RF signal.

[0069] In an exemplary embodiment, the first amplifier 51 is a low-noise amplifier (LNA), and the second amplifier 52 is a power amplifier (PA). The filter 100 can be a duplex filter, such as a frequency division duplex (FDD) filter or a time division duplex (TDD) filter. Figure 1 shows two filters, one an FDD filter and the other a TDD filter.

[0070] Based on this, this application embodiment also provides a filter 100. Please refer to Figure 2, which is a schematic diagram of the circuit structure of the filter disclosed in this application embodiment. The filter 100 may include at least an input terminal In, an output terminal Out, a series branch B1, and at least one parallel branch B2. The series branch B1 is connected between the input terminal In and the output terminal Out. One end of the parallel branch B2 is connected to the series branch B1, and the other end is connected to the ground terminal GND. At least two series-connected surface acoustic wave (SAW) resonators 200 are provided in the series branch B1, and each parallel branch B2 is provided with parallel SAW resonators 200. The multiple SAW resonators 200 are electrically connected. The filter 100 receives radio frequency (RF) signals through the input terminal In and transmits RF signals through the output terminal Out. The passband frequency bands of the multiple SAW resonators 200 may be different.

[0071] This application also provides a surface acoustic wave resonator 200. Please refer to Figures 3 and 4. Figure 3 is a top view of the filter disclosed in this application. Figure 4 is a first cross-sectional view of the filter shown in Figure 3 along direction II. The filter shown in Figure 4 is a normal surface acoustic wave filter (Normal SAW).

[0072] The surface acoustic wave resonator 200 includes an interdigital transducer 210 and a piezoelectric layer 220. The interdigital transducer 210 protrudes from one surface of the piezoelectric layer 220.

[0073] Specifically, when the interdigital transducer 210 excites surface acoustic waves, it receives an alternating electrical signal and generates an alternating electric field corresponding to the signal. The piezoelectric layer 220 deforms under the influence of this alternating electric field. Since the electric field strength of the alternating electric field varies, the degree of deformation of the piezoelectric layer 220 changes over time, thereby generating an acoustic wave signal on the surface of the piezoelectric layer 220 and propagating thereon. This phenomenon of the piezoelectric layer 220 deforming under the influence of an alternating electric field is called the Converse Piezoelectricity Effect.

[0074] When interdigital transducer 210 receives surface acoustic waves, the acoustic signal propagates across the piezoelectric layer 220 to the region where another interdigital transducer 210 is located. The acoustic signal causes deformation of the piezoelectric layer 220 in that region. To resist the deformation, the piezoelectric layer 220 generates equal amounts of positive and negative charges on its opposite surfaces, thus forming an electrical signal on the interdigital transducer 210. The phenomenon of the deformed piezoelectric layer 220 generating positive and negative charges is called the positive piezoelectric effect.

[0075] In an exemplary embodiment, the material of the piezoelectric layer 220 includes lithium tantalate (LiTaO3, LT) or lithium niobate (LiNbO3, LN).

[0076] In other embodiments, the surface acoustic wave resonator 200 may further include a reflection structure disposed on opposite sides of the interdigital transducer 210 and located in the piezoelectric layer 220. The reflection structure confines the energy (sound wave) excited by the interdigital transducer 210 to the region where the interdigital transducer 210 is located, thereby improving the quality factor of the surface acoustic wave resonator 200.

[0077] In another embodiment, please refer to FIG5, which is a second cross-sectional schematic diagram of the filter shown in FIG3 along direction II. The filter shown in FIG5 is a thin-film filter (Film SAW). The surface acoustic wave resonator 200 also includes a functional layer 230 and a support layer 240. The functional layer 230 is disposed on the surface of the piezoelectric layer 220 opposite to the interdigital transducer 210, and the support layer 240 is disposed on the surface of the functional layer 230 opposite to the piezoelectric layer 220. The support layer 240 is used to provide the surface on which the functional layer 230 is formed, and the functional layer 230 is used to reduce the acoustic wave propagation speed of the piezoelectric layer 220.

[0078] In an exemplary embodiment, the material of the functional layer 230 is a low-velocity material, including silicon dioxide. The material of the support layer 240 includes silicon, sapphire, diamond, glass, etc.

[0079] Please refer to Figure 6, which is a schematic diagram of the first structure of the interdigital transducer disclosed in this application embodiment. For ease of description, the length direction of the interdigital transducer 210 shown in Figure 6 is defined as the X-axis direction, the width direction of the interdigital transducer 210 is defined as the Y-axis direction, and the thickness direction of the interdigital transducer 210 is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions are mutually perpendicular. The Y-axis direction can also be defined as a first direction, the X-axis direction as a second direction, and the Z-axis direction as a third direction. The directional terms such as "upper" and "lower" mentioned in the description of the embodiments of this application are based on the orientation shown in Figure 6 of the specification, with "upper" or "top" referring to the positive Z-axis direction and "lower" or "bottom" referring to the negative Z-axis direction. These terms do not constitute a limitation on the interdigital transducer 210 in actual application scenarios.

[0080] In this embodiment, the interdigital transducer 210 includes a first busbar 211, a second busbar 212, a plurality of first electrode fingers 213, a plurality of second electrode fingers 214, a plurality of first dielectric blocks 215, and a plurality of second dielectric blocks 216. The first busbar 211 and the second busbar 212 are arranged along the Y-axis and spaced apart from each other, are parallel to each other, and both the first busbar 211 and the second busbar 212 extend towards the X-axis. The first busbar 211, the second busbar 212, the first electrode fingers 213, and the second electrode fingers 214 are all connected to the piezoelectric layer 220.

[0081] Multiple first electrode fingers 213 are sequentially spaced along the X-axis. The first electrode fingers 213 are disposed on the surface of the first busbar 211 facing the second busbar 212. The first electrode fingers 213 are connected to the first busbar 211 and extend towards the second busbar 212, i.e., the first electrode fingers 213 extend away from the Y-axis direction, and are spaced apart from the second busbar 212. Multiple second electrode fingers 214 are sequentially spaced along the X-axis. The second electrode fingers 214 are disposed on the surface of the second busbar 212 facing the first busbar 211. The second electrode fingers 214 are connected to the second busbar 212 and extend towards the first busbar 211, i.e., the second electrode fingers 214 extend towards the Y-axis direction, and are spaced apart from the first busbar 211.

[0082] Multiple first electrode fingers 213 and multiple second electrode fingers 214 are arranged alternately along the X-axis. That is, in the X-axis direction, the multiple first electrode fingers 213 and multiple second electrode fingers 214 are arranged in the following order: first electrode finger 213, second electrode finger 214, first electrode finger 213, second electrode finger 214, with the first electrode finger 213 spaced apart from its adjacent second electrode finger 214.

[0083] Each first electrode finger 213 is electrically connected to the first busbar 211, and each second electrode finger 214 is electrically connected to the second busbar 212. When the interdigital transducer 210 excites surface acoustic waves, each first electrode finger 213 receives an alternating signal through the first busbar 211, and each second electrode finger 214 receives an alternating signal through the second busbar 212. The first electrode fingers 213 and second electrode fingers 214 form an alternating electric field, and the piezoelectric layer 220 generates an acoustic wave signal according to the alternating electric field.

[0084] When the interdigital transducer 210 receives surface acoustic waves, the acoustic wave signal causes the piezoelectric layer 220 below the interdigital transducer 210 to deform. To resist the deformation, the piezoelectric layer 220 generates equal amounts of positive and negative charges on its opposite surfaces to form electrical signals on the first electrode finger 213 and the second electrode finger 214. The electrical signals are output through the first electrode finger 213 and the second electrode finger 214.

[0085] In an exemplary embodiment, referring to Figure 6, the distance between two adjacent first electrode fingers 213 is the wavelength λ of the surface acoustic wave, and the distance between two adjacent second electrode fingers 214 is the wavelength λ of the surface acoustic wave. The wavelength λ is inversely proportional to the frequency of the surface acoustic wave. The wavelength λ is from 1.5 μm to 6 μm, for example, 1.5 μm, 2 μm, 2.7 μm, 3.5 μm, 4 μm, 4.6 μm, 5.4 μm, 6 μm, or other values, and this application does not impose specific limitations on it.

[0086] The dimension a of the first electrode finger 213 along the X-axis is MR×λ, where MR is the duty cycle of the first electrode finger 213, and the value of MR ranges from 0.4 to 0.75. The dimension a of the first electrode finger 213 along the X-axis is from 0.6 μm to 4.5 μm, for example, 0.6 μm, 1 μm, 1.3 μm, 1.8 μm, 2.5 μm, 3 μm, 3.4 μm, 3.9 μm, 4.5 μm, or other values, and this application does not impose specific limitations on this. The dimension of the second electrode finger 214 along the X-axis is equal to the dimension of the first electrode finger 213 along the X-axis.

[0087] In an exemplary embodiment, the density of the first electrode finger 213 and the second electrode finger 214 is greater than or equal to 8900 kg / m³. The higher the density of the electrode fingers, the lower the velocity of the surface acoustic wave. For a filter at a specific frequency, reducing the velocity of sound can reduce the wavelength, thereby reducing the size of the resonator and achieving filter miniaturization. The materials of the first electrode finger 213 and the second electrode finger 214 include at least one of the following: molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), copper (Cu), tantalum (Ta), tungsten (W), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au).

[0088] In an exemplary embodiment, the first electrode finger 213 and the second electrode finger 214 can be multilayer (at least two layers) composite electrodes. The first electrode finger 213 and the second electrode finger 214 comprise high-density materials and highly conductive materials, such as multilayer electrodes composed of Pt and Al, Au and Al, W and Al, Mo and Al, etc. By setting the electrode fingers as multilayer composite electrodes, one layer of the composite electrode can be used to control the velocity of surface acoustic waves, and the other layer can be used to control the resistance of the electrode fingers, thereby reducing the insertion loss of the filter.

[0089] Referring to Figure 6, a first dielectric block 215 is disposed at the end of the first electrode finger 213 opposite to the end of the first busbar 211 and extends to the second busbar 212. The first dielectric block 215 is fixedly connected to both the first electrode finger 213 and the second busbar 212. A second dielectric block 216 is disposed at the end of the second electrode finger 214 opposite to the end of the second busbar 212 and extends to the first busbar 211. The second dielectric block 216 is fixedly connected to both the second electrode finger 214 and the first busbar 211. Multiple first dielectric blocks 215 are spaced apart from each other, and multiple second dielectric blocks 216 are spaced apart from each other.

[0090] The two main vibration modes of surface acoustic waves (SAWs) are Rayleigh modes and shear horizontal (SH) modes. Please refer to Figure 7, which is a schematic diagram of the vibration modes of SAWs, showing the vibration forms of the Rayleigh and SH modes. The Rayleigh mode vibrates in a plane corresponding to the X and Z axes, with an elliptical trajectory, and propagates in the X-axis direction. The SH mode vibrates in a plane corresponding to the X and Y axes, with the vibration direction along the Y-axis, and propagates in the X-axis direction.

[0091] Due to the structure of the interdigital transducer, the vibration amplitude of the electrode finger is greatest at its tip, generating SH transverse mode vibration. The tip is the end of the electrode finger facing away from the busbar it is connected to. Please refer to Figure 8, which shows the admittance characteristic curve of a resonator in the prior art. The dashed line in Figure 8 represents the real part of the admittance, and the solid line represents the absolute value of the admittance. The highest point of the solid line is the resonant point, and the lowest point is the anti-resonant point. There is a relatively sharp peak between the resonant and anti-resonant points; this sharp peak represents the SH transverse mode. A relatively sharp peak also exists near the Rayleigh mode; this sharp peak represents the Rayleigh transverse mode.

[0092] Existing technologies suppress SH transverse modes by reflecting sound waves through high and low sound velocity regions at the tips of the electrode fingers. As surface acoustic wave (SAW) resonators become increasingly miniaturized, reducing their size hinges on reducing their area. This can be achieved by decreasing the speed of sound of SAW waves, thereby reducing the spacing between the electrode fingers and thus the resonator length. Alternatively, increasing the duty cycle of the electrode fingers increases the static capacitance of the resonator, further reducing its area. To achieve high-performance SAW filters, miniaturization must be achieved while suppressing SH transverse modes, ensuring a smooth passband curve free of sharp peaks and normal harmonics. To suppress SH transverse modes, the density of the electrode fingers is typically increased. However, increasing the finger density reduces the speed difference between the Rayleigh and SH modes, leading to coupling between them and forming coupled modes. The sharp peak between the Rayleigh and SH modes constitutes the coupled mode. The frequency band near the SH mode is the operating frequency band of the resonator, requiring strict suppression of both SH transverse modes and coupled modes.

[0093] As can be seen from the above, the existing technology cannot simultaneously suppress the SH transverse mode and the coupled mode, as both the SH transverse mode and the coupled mode are miscellaneous modes.

[0094] In this application, the first dielectric block 215 is used to reduce the vibration amplitude of the first electrode finger 213 in the Y-axis direction, and the second dielectric block 216 is used to reduce the vibration amplitude of the second electrode finger 214 in the Y-axis direction, thereby suppressing the SH transverse mode and the coupled mode. Please refer to Figure 9, which is a schematic diagram of the admittance characteristic curves of the surface acoustic wave resonator disclosed in this application embodiment. As can be seen from Figure 9, the admittance curve between the resonant point and the anti-resonant point is smooth and free of clutter. The real part of the admittance curve does not have a sharp peak between the resonant point and the anti-resonant point, thus effectively suppressing the SH transverse mode. The admittance curve between the Rayleigh transverse mode and the SH mode is smooth and free of clutter. The real part of the admittance curve does not have a sharp peak between the Rayleigh transverse mode and the SH mode, thus effectively suppressing the coupled mode.

[0095] Furthermore, the first dielectric block 215 is also used to reduce the vibration amplitude of the first electrode finger 213 in the Z-axis direction, and the second dielectric block 216 is also used to reduce the vibration amplitude of the second electrode finger 214 in the Z-axis direction, so as to suppress Rayleigh transverse modes. As can be seen from Figure 9, compared with Figure 7, the peak values ​​of several sharp peaks near the resonance point of the Rayleigh transverse mode are reduced, thereby suppressing the Rayleigh transverse mode.

[0096] Please refer to Figure 10, which is a schematic diagram of the busbar and electrode fingers shown in Figure 6. Each first electrode finger 213 has a first opening 213a at its end opposite to the first busbar 211, and the first opening 213a penetrates the first electrode finger 213 along the Z-axis. The second busbar 212 has multiple second openings 212a, and the second openings 212a penetrate the second busbar 212 along the Z-axis. One second opening 212a and one first opening 213a are arranged sequentially along the Y-axis.

[0097] Each second electrode finger 214 has a third opening 214a at its end opposite to the second busbar 212, and the third opening 214a penetrates the second electrode finger 214 along the Z-axis. The first busbar 211 has multiple fourth openings 211a, and the fourth openings 211a penetrate the first busbar 211 along the Z-axis. One third opening 214a and one fourth opening 211a are arranged sequentially along the Y-axis.

[0098] The first opening 213a, the second opening 212a, the third opening 214a and the fourth opening 211a can be prismatic holes or cylindrical holes, and this application does not impose specific restrictions on them.

[0099] The dimension of the first opening 213a along the X-axis is 0.1λ to 0.5λ, and the dimension of the first opening 213a along the X-axis is 0.15µm to 3µm, for example, 0.15µm, 0.5µm, 0.9µm, 1.8µm, 2µm, 2.4µm, 3µm, or other values. This application does not impose specific limitations on these values. The dimension of the first opening 213a along the Y-axis is also 0.1λ to 0.5λ.

[0100] Understandably, due to process limitations, the dimensions of the first opening 213a along the X-axis and Y-axis directions will not be less than 0.1λ.

[0101] The dimensions of the second opening 212a, the third opening 214a, and the fourth opening 211a along the X-axis are equal to the dimensions of the first opening 213a along the X-axis. The dimensions of the second opening 212a, the third opening 214a, and the fourth opening 211a along the Y-axis are also equal to the dimensions of the first opening 213a along the Y-axis.

[0102] In an exemplary embodiment, the materials of the first dielectric block 215 and the second dielectric block 216 include silicon dioxide (SiO2) or silicon nitride (Si3N4).

[0103] Please refer to Figure 11, which is a cross-sectional view of the interdigital transducer shown in Figure 6 along the II-II direction. The first dielectric block 215 includes a first dielectric body 215a, a first connector 215b, a first insert 215c, and a second insert 215d. To facilitate the description of the cooperation relationship between the first dielectric block 215 and the first electrode finger 213, and the cooperation relationship between the first dielectric block 215 and the second busbar 212, the dotted lines in Figure 11 exemplarily distinguish the first dielectric body 215a, the first connector 215b, the first insert 215c, and the second insert 215d. The first dielectric body 215a, the first insert 215c, and the second insert 215d are all disposed on the surface of the first connector 215b facing away from the Z-axis direction, and the first dielectric body 215a, the first insert 215c, and the second insert 215d are all fixedly connected to the first connector 215b. The first embedding body 215c and the second embedding body 215d are disposed on opposite sides of the first connecting body 215b along the Y-axis direction, and the first embedding body 215c and the second embedding body 215d are spaced apart from the first dielectric body 215a. The first dielectric body 215a, the first embedding body 215c, and the second embedding body 215d are also connected to the piezoelectric layer 220.

[0104] A first dielectric body 215a is disposed between the first electrode finger 213 and the second busbar 212, and is fixedly connected to both the first electrode finger 213 and the second busbar 212. A first insert 215c is disposed within the first opening 213a of the first electrode finger 213, i.e., the first insert 215c is embedded within the first electrode finger 213. The first insert 215c is fixedly connected to the first electrode finger 213. A second insert 215d is disposed within the second opening 212a of the second busbar 212, i.e., the second insert 215d is embedded within the second busbar 212. The second insert 215d is fixedly connected to the second busbar 212. A first connector 215b is disposed on the surface of the first dielectric body 215a facing away from the piezoelectric layer 220, i.e., the first connector 215b is disposed on the surface of the first electrode finger 213 facing away from the piezoelectric layer 220 and the surface of the second busbar 212 facing away from the piezoelectric layer 220.

[0105] Specifically, the first dielectric body 215a reduces the vibration amplitude of the first electrode finger 213 in both the Y-axis and Z-axis directions. The first connector 215b also reduces the vibration amplitude of the first electrode finger 213 in both the Y-axis and Z-axis directions. The first insert 215c increases the connection strength between the first dielectric block 215 and the first electrode finger 213. The second insert 215d increases the connection strength between the first dielectric block 215 and the second busbar 212.

[0106] In an exemplary embodiment, the dimension of the first dielectric body 215a along the Y-axis direction (the distance between the first electrode finger 213 and the second busbar 212) is 0.1λ to 0.5λ, specifically 0.15um to 3um, for example, 0.15um, 0.5um, 0.9um, 1.8um, 2um, 2.4um, 3um, or other values. This application does not impose any specific limitations on this.

[0107] In an exemplary embodiment, the dimensions of the first dielectric body 215a, the first insert 215c, and the second insert 215d along the Z-axis are equal to the dimensions of the first electrode finger 213 along the Z-axis. The dimensions of the first electrode finger 213 along the Z-axis are from 100 nm to 500 nm, for example, 100 nm, 140 nm, 210 nm, 270 nm, 350 μm, 400 nm, 420 nm, 500 nm, or other values. This application does not impose specific limitations on these values.

[0108] In an exemplary embodiment, the dimension of the first connector 215b along the Y-axis is 3 to 8 times the dimension of the first dielectric body 215a along the Y-axis, specifically 0.45um to 24um, for example, 0.45um, 1um, 5.5um, 10um, 16um, 20um, 22um, 24um, or other values. This application does not impose specific limitations on this. The dimension of the first connector 215b along the Y-axis is larger than the dimension of the first dielectric body 215a along the Y-axis, so that the first connector 215b can be fixedly connected to the first electrode finger 213 and the second busbar 212.

[0109] In an exemplary embodiment, the dimension of the first connector 215b along the Z-axis is 50nm to 500nm, for example, 50nm, 100nm, 160nm, 200nm, 300nm, 400nm, 500nm, or other values, and this application does not impose specific limitations on this. The larger the dimension of the first connector 215b along the Z-axis, the greater the vibration amplitude of the first electrode finger 213 lowered by the first dielectric block 215 in the Y and X-axis directions.

[0110] In an exemplary embodiment, the dimension of the first insert 215c along the X-axis is equal to the dimension of the first opening 213a along the X-axis, and the dimension of the first insert 215c along the Y-axis is equal to the dimension of the first opening 213a along the Y-axis. The dimension of the second insert 215d along the X-axis is equal to the dimension of the second opening 212a along the X-axis, and the dimension of the second insert 215d along the Y-axis is equal to the dimension of the second opening 212a along the Y-axis.

[0111] Please refer to Figure 12, which is a cross-sectional view of the interdigital transducer shown in Figure 6 along the III-III direction. The second dielectric block 216 includes a second dielectric body 216a, a second connector 216b, a third insert 216c, and a fourth insert 216d. To facilitate the description of the cooperation relationship between the second dielectric block 216 and the second electrode finger 214, as well as the cooperation relationship between the second dielectric block 216 and the first busbar 211, the dotted lines in Figure 12 exemplarily distinguish the second dielectric body 216a, the second connector 216b, the third insert 216c, and the fourth insert 216d. The second dielectric body 216a, the third insert 216c, and the fourth insert 216d are all disposed on the surface of the second connector 216b facing away from the Z-axis direction, and the second dielectric body 216a, the third insert 216c, and the fourth insert 216d are all fixedly connected to the second connector 216b. The third embedding 216c and the fourth embedding 216d are disposed on opposite sides of the second connector 216b along the Y-axis direction, and the third embedding 216c and the fourth embedding 216d are spaced apart from the second dielectric body 216a. The second dielectric body 216a, the third embedding 216c, and the fourth embedding 216d are also connected to the piezoelectric layer 220.

[0112] The second dielectric body 216a is disposed between the second electrode finger 214 and the first busbar 211, and is fixedly connected to both the second electrode finger 214 and the first busbar 211. The third insert 216c is disposed within the third opening 214a of the second electrode finger 214, i.e., the third insert 216c is embedded within the second electrode finger 214. The third insert 216c is fixedly connected to the second electrode finger 214. The fourth insert 216d is disposed within the fourth opening 211a of the first busbar 211, i.e., the fourth insert 216d is embedded within the first busbar 211. The fourth insert 216d is fixedly connected to the first busbar 211. The second connector 216b is disposed on the surface of the second dielectric body 216a facing away from the piezoelectric layer 220, that is, the second connector 216b is disposed on the surface of the second electrode finger 214 facing away from the piezoelectric layer 220 and the surface of the first busbar 211 facing away from the piezoelectric layer 220.

[0113] Specifically, the second dielectric body 216a reduces the vibration amplitude of the second electrode finger 214 in the Y-axis direction and the Z-axis direction. The second connector 216b reduces the vibration amplitude of the second electrode finger 214 in both the Y-axis and Z-axis directions. The third insert 216c increases the connection strength between the second dielectric block 216 and the second electrode finger 214. The fourth insert 216d increases the connection strength between the second dielectric block 216 and the first busbar 211.

[0114] In an exemplary embodiment, the dimension of the second dielectric body 216a along the Y-axis (the distance between the second electrode finger 214 and the first busbar 211) is equal to the dimension of the second dielectric body 216a along the Y-axis. The dimension of the second connector 216b along the Y-axis is equal to the dimension of the first connector 215b along the Y-axis. The dimension of the second connector 216b along the Y-axis is equal to the dimension of the first connector 215b along the Y-axis. The dimensions of the second dielectric body 216a, the third insert 216c, and the fourth insert 216d along the Z-axis are equal to the dimensions of the second electrode finger 214 along the Z-axis, and the dimension of the second electrode finger 214 along the Z-axis is equal to the dimension of the first electrode finger 213 along the Z-axis. The dimension of the second connector 216b along the Z-axis is equal to the dimension of the first connector 215b along the Z-axis.

[0115] In an exemplary embodiment, the dimension of the second connector 216b along the Y-axis is larger than the dimension of the second dielectric body 216a along the Y-axis, so that the second connector 216b can be fixedly connected to the second electrode finger 214 and the first busbar 211. The larger the dimension of the second connector 216b along the Z-axis, the greater the vibration amplitude of the lowered second electrode finger 214 in the Y and X-axis directions.

[0116] In an exemplary embodiment, the dimension of the third insert 216c along the X-axis is equal to the dimension of the third opening 214a along the X-axis, and the dimension of the third insert 216c along the Y-axis is equal to the dimension of the third opening 214a along the Y-axis. The dimension of the fourth insert 216d along the X-axis is equal to the dimension of the fourth opening 211a along the X-axis, and the dimension of the fourth insert 216d along the Y-axis is equal to the dimension of the fourth opening 211a along the Y-axis.

[0117] In other embodiments, the first medium block 215 may include only the first medium body 215a, or the first medium block 215 may include only the first medium body 215a and the first connector 215b. The second medium block 216 may include only the second medium body 216a, or the second medium block 216 may include only the second medium body 216a and the second connector 216b.

[0118] Please refer to Figure 13, which is a schematic diagram of the second structure of the interdigital transducer disclosed in this application embodiment. The difference between the interdigital transducer shown in Figure 13 and the interdigital transducer shown in Figure 6 is that multiple first dielectric blocks 215 are connected sequentially along the X-axis direction, and multiple second dielectric blocks 216 are connected sequentially along the X-axis direction. For a description of the structural similarities between the interdigital transducer shown in Figure 13 and the interdigital transducer shown in Figure 6, please refer to the relevant description in Figure 6, which will not be repeated here.

[0119] Specifically, in Figure 13, dashed lines exemplarily distinguish multiple first medium blocks 215, and dashed lines exemplarily distinguish multiple second medium blocks 216. Each first medium block 215 is connected to its adjacent first medium block 215, and each second medium block 216 is connected to its adjacent second medium block 216.

[0120] Understandably, before forming multiple spaced first dielectric blocks 215, the positions of the multiple first dielectric blocks 215 need to be defined through an etching process. However, forming multiple connected first dielectric blocks 215 does not require defining the positions of the multiple first dielectric blocks 215. Therefore, connecting multiple first dielectric blocks 215 sequentially along the X-axis simplifies the fabrication process of the multiple first dielectric blocks 215. Similarly, multiple second dielectric blocks 216 are connected sequentially along the X-axis, which will not be elaborated further here.

[0121] Please refer to Figure 14, which is a schematic diagram of the third structure of the interdigital transducer disclosed in this application embodiment. The difference between the interdigital transducer shown in Figure 14 and the interdigital transducer shown in Figure 6 is that the interdigital transducer shown in Figure 14 further includes a third busbar 217 and a fourth busbar 218. For a description of the structural similarities between the interdigital transducer shown in Figure 14 and the interdigital transducer shown in Figure 6, please refer to the relevant description in Figure 6, which will not be repeated here.

[0122] Specifically, the third busbar 217 extends along the Y-axis and is located on the side of the first busbar 211 opposite to the second busbar 212. The third busbar 217 is spaced apart from the first busbar 211 and is parallel to the first busbar 211. The fourth busbar 218 extends along the Y-axis and is located on the side of the second busbar 212 opposite to the first busbar 211. The fourth busbar 218 is spaced apart from the second busbar 212 and is parallel to the second busbar 212.

[0123] The interdigital transducer 210 also includes a plurality of first connecting fingers 221 and a plurality of second connecting fingers 222. The plurality of first connecting fingers 221 are arranged at intervals along the X-axis, each first connecting finger 221 being positioned between a first busbar 211 and a third busbar 217, and fixedly connected to both the first busbar 211 and the third busbar 217. A first connecting finger 221 and a first electrode finger 213 are arranged at intervals along the Y-axis. The plurality of second connecting fingers 222 are arranged at intervals along the X-axis, each second connecting finger 222 being positioned between a second busbar 212 and a fourth busbar 218, and fixedly connected to both the second busbar 212 and the fourth busbar 218. A second connecting finger 222 and a second electrode finger 214 are arranged at intervals along the Y-axis.

[0124] The first connecting finger 221 and the third bus bar 217 are used to form high and low sound velocity regions to reflect the energy propagating to these regions and improve the filter's performance. The second connecting finger 222 and the fourth bus bar 218 are also used to form high and low sound velocity regions to reflect the energy propagating to these regions and improve the filter's performance.

[0125] Please refer to Figure 15, which is a schematic diagram of the fourth structure of the interdigital transducer disclosed in this application. The difference between the interdigital transducer shown in Figure 15 and the interdigital transducer shown in Figure 6 is that the interdigital transducer shown in Figure 15 further includes multiple first pseudo-fingers 223 and multiple second pseudo-fingers 224. For a description of the structural similarities between the interdigital transducer shown in Figure 15 and the interdigital transducer shown in Figure 6, please refer to the relevant description in Figure 6, which will not be repeated here.

[0126] Specifically, multiple first dummy fingers 223 are arranged at intervals along the X-axis. Each first dummy finger 223 is located at the end of the first electrode finger 213 opposite to the first busbar 211, spaced apart from the first electrode finger 213, and fixedly connected to the second busbar 212. Multiple second dummy fingers 224 are arranged at intervals along the X-axis. Each second dummy finger 224 is located at the end of the second electrode finger 214 opposite to the second busbar 212, spaced apart from the second electrode finger 214, and fixedly connected to the first busbar 211.

[0127] The first pseudo-finger 223 is used to suppress the lateral parasitic resonance generated at the gap between the first electrode finger 213 and the second bus bar 212, and the second pseudo-finger 224 is used to suppress the lateral parasitic resonance generated at the gap between the second electrode finger 214 and the first bus bar 211.

[0128] In an exemplary embodiment, a first dielectric block 215 is disposed at the end of the first electrode finger 213 opposite to the first busbar 211 and extends to the first dummy finger 223. The first dielectric block 215 is fixedly connected to the first electrode finger 213 and the first dummy finger 223 respectively. A second dielectric block 216 is disposed at the end of the second electrode finger 214 opposite to the second busbar 212 and extends to the second dummy finger 224. The second dielectric block 216 is fixedly connected to the second electrode finger 214 and the second dummy finger 224 respectively.

[0129] In an exemplary embodiment, please refer to Figure 16, which is a schematic diagram of the busbar and electrode fingers shown in Figure 15. Each first electrode finger 213 has a first opening 213a at its end opposite to the first busbar 211. Each first dummy finger 223 has a fifth opening 223a, which penetrates the first dummy finger 223 along the Z-axis. A fifth opening 223a and a first opening 213a are arranged sequentially along the Y-axis. Each second electrode finger 214 has a third opening 214a at its end opposite to the second busbar 212. Each second dummy finger 224 has a sixth opening 224a, which penetrates the second dummy finger 224 along the Z-axis. A sixth opening 224a and a third opening 214a are arranged sequentially along the Y-axis.

[0130] In an exemplary embodiment, the fifth opening 223a has dimensions of 0.15µm to 3µm along both the X-axis and Y-axis directions. The sixth opening 224a has dimensions of 0.15µm to 3µm along both the X-axis and Y-axis directions.

[0131] Please refer to Figure 17, which is a cross-sectional view of the interdigital transducer shown in Figure 15 along the IV-IV direction. The first dielectric block 215 includes a first dielectric body 215a, a first connector 215b, a first insert 215c, and a second insert 215d. To facilitate the description of the cooperation relationship between the first dielectric block 215 and the first electrode finger 213, and between the first dielectric block 215 and the first dummy finger 223, the dotted lines in Figure 17 exemplarily distinguish the first dielectric body 215a, the first connector 215b, the first insert 215c, and the second insert 215d. The first dielectric body 215a is disposed between the first electrode finger 213 and the first dummy finger 223, and the first dielectric body 215a is fixedly connected to both the first electrode finger 213 and the first dummy finger 223. The first insert 215c is disposed within the first opening 213a of the first electrode finger 213, that is, the first insert 215c is embedded within the first electrode finger 213. The first insert 215c is fixedly connected to the first electrode finger 213. The second insert 215d is disposed within the fifth opening 223a of the first dummy finger 223, that is, the second insert 215d is embedded within the first dummy finger 223. The second insert 215d is fixedly connected to the first dummy finger 223. The first connector 215b is disposed on the surface of the first dielectric body 215a facing away from the piezoelectric layer 220, that is, the first connector 215b is disposed on the surface of the first electrode finger 213 facing away from the piezoelectric layer 220 and the surface of the first dummy finger 223 facing away from the piezoelectric layer 220.

[0132] Please refer to Figure 18, which is a cross-sectional view of the interdigital transducer shown in Figure 15 along the VV direction. The second dielectric block 216 includes a second dielectric body 216a, a second connector 216b, a third insert 216c, and a fourth insert 216d. To facilitate the description of the cooperation relationship between the second dielectric block 216 and the second electrode finger 214, and between the second dielectric block 216 and the second dummy finger 224, the dotted lines in Figure 18 exemplarily distinguish the second dielectric body 216a, the second connector 216b, the third insert 216c, and the fourth insert 216d. The second dielectric body 216a is disposed between the second electrode finger 214 and the second dummy finger 224, and the second dielectric body 216a is fixedly connected to both the second electrode finger 214 and the second dummy finger 224. The third insert 216c is disposed within the third opening 214a of the second electrode finger 214, that is, the third insert 216c is embedded within the second electrode finger 214. The third insert 216c is fixedly connected to the second electrode finger 214. The fourth insert 216d is disposed within the sixth opening 224a of the second dummy finger 224, that is, the fourth insert 216d is embedded within the second dummy finger 224. The fourth insert 216d is fixedly connected to the second dummy finger 224. The second connector 216b is disposed on the surface of the second dielectric body 216a facing away from the piezoelectric layer 220, that is, the second connector 216b is disposed on the surface of the second electrode finger 214 facing away from the piezoelectric layer 220 and the surface of the second dummy finger 224 facing away from the piezoelectric layer 220.

[0133] In an exemplary embodiment, a plurality of first medium blocks 215 are spaced apart from each other, and a plurality of second medium blocks 216 are spaced apart from each other.

[0134] In other embodiments, the first medium block 215 may include only the first medium body 215a, or the first medium block 215 may include only the first medium body 215a and the first connector 215b. The second medium block 216 may include only the second medium body 216a, or the second medium block 216 may include only the second medium body 216a and the second connector 216b.

[0135] Please refer to Figure 19, which is a schematic diagram of the fifth structure of the interdigital transducer disclosed in this application. The difference between the interdigital transducer shown in Figure 19 and the interdigital transducer shown in Figure 15 is that multiple first dielectric blocks 215 are connected sequentially along the X-axis, and multiple second dielectric blocks 216 are connected sequentially along the X-axis. For a description of the sequential connection of the multiple first dielectric blocks 215 and the multiple second dielectric blocks 216 along the X-axis, please refer to the description of the interdigital transducer shown in Figure 13, which will not be repeated here.

[0136] Please refer to Figure 20, which is a schematic diagram of the sixth structure of the interdigital transducer disclosed in this application. The difference between the interdigital transducer shown in Figure 20 and the interdigital transducer shown in Figure 15 is that the interdigital transducer shown in Figure 20 further includes a third busbar 217, a fourth busbar 218, a plurality of first connecting fingers 221, and a plurality of second connecting fingers 222. For a description of the third busbar 217, the fourth busbar 218, the plurality of first connecting fingers 221, and the plurality of second connecting fingers 222, please refer to the interdigital transducer shown in Figure 14, which will not be repeated here.

[0137] In one possible implementation, the formation process of the interdigital transducer 210 includes: cleaning the wafer; forming a first busbar 211, a second busbar 212, a first electrode finger 213, and a second electrode finger 214 on the wafer through photolithography, development, coating, and lift-off processes; forming a first dielectric block 215 and a second dielectric block 216 through photolithography, development, coating, and lift-off processes; forming a passivation layer through a coating process, the passivation layer covering the interdigital transducer 210; openings in the passivation layer through photolithography, development, and etching processes, exposing the first busbar 211 and the second busbar 212 through the openings; and forming pads in the openings and on the surface of the passivation layer through photolithography, development, coating, and lift-off processes.

[0138] It should be noted that if the interdigital transducer 210 includes a third busbar 217, a fourth busbar 218, a first connecting finger 221, and a second connecting finger 222, these components are formed simultaneously with the first busbar 211, the second busbar 212, the first electrode finger 213, and the second electrode finger 214. If the interdigital transducer 210 includes a first dummy finger 223 and a second dummy finger 224, these components are formed simultaneously with the first busbar 211, the second busbar 212, the first electrode finger 213, and the second electrode finger 214.

[0139] In another possible implementation, the first busbar 211, the second busbar 212, the first electrode finger 213, and the second electrode finger 214 are formed on the wafer through coating, photolithography, development, and etching processes.

[0140] In summary, the electronic device 1 provided in this application embodiment includes a radio frequency front-end module 20, which includes a filter 100, and the filter 100 includes a surface acoustic wave resonator 200. The surface acoustic wave resonator 200 includes an interdigital transducer 210, which includes a first bus bar 211, a second bus bar 212, a plurality of first electrode fingers 213, a plurality of second electrode fingers 214, a plurality of first dielectric blocks 215, and a plurality of second dielectric blocks 216. A first dielectric block 215 is disposed at the end of the first electrode finger 213 opposite to the end of the first busbar 211 and extends to the second busbar 212. The first dielectric block 215 is fixedly connected to both the first electrode finger 213 and the second busbar 212. A second dielectric block 216 is disposed at the end of the second electrode finger 214 opposite to the end of the second busbar 212 and extends to the first busbar 211. The second dielectric block 216 is fixedly connected to both the second electrode finger 214 and the first busbar 211. Alternatively,

[0141] The interdigital transducer 210 includes a first busbar 211, a second busbar 212, a plurality of first electrode fingers 213, a plurality of second electrode fingers 214, a plurality of first dummy fingers 223, a plurality of second dummy fingers 224, a plurality of first dielectric blocks 215, and a plurality of second dielectric blocks 216. The first dielectric blocks 215 are disposed at the end of the first electrode finger 213 opposite to the first busbar 211 and extend to the first dummy finger 223. The first dielectric blocks 215 are fixedly connected to the first electrode finger 213 and the first dummy finger 223 respectively. The second dielectric blocks 216 are disposed at the end of the second electrode finger 214 opposite to the second busbar 212 and extend to the second dummy finger 224. The second dielectric blocks 216 are fixedly connected to the second electrode finger 214 and the second dummy finger 224 respectively.

[0142] The first dielectric block 215 is used to reduce the vibration amplitude of the first electrode finger 213 in the second direction, and the second dielectric block 216 is used to reduce the vibration amplitude of the second electrode finger 214 in the second direction. By reducing the vibration amplitude of the first electrode finger 213 in the second direction and reducing the vibration amplitude of the second electrode finger 214 in the second direction, the miscellaneous modes in the vibration modes of the surface acoustic wave resonator can be suppressed. The miscellaneous modes include SH transverse modes and coupled modes.

[0143] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments, and making equivalent changes according to the claims of this application, still falls within the scope of this application.

Claims

1. A surface acoustic wave resonator, characterized by, The device includes a piezoelectric layer and an interdigital transducer. The interdigital transducer is disposed on a surface of the piezoelectric layer. The interdigital transducer includes a first busbar, a second busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers. The first busbar and the second busbar are arranged along a first direction and spaced apart. The plurality of first electrode fingers are connected to the first busbar and extend into the second busbar. The first electrode fingers are spaced apart from the second busbar. The plurality of second electrode fingers are connected to the second busbar and extend into the first busbar. The second electrode fingers are spaced apart from the first busbar. The plurality of first electrode fingers and the plurality of second electrode fingers are arranged alternately and spaced apart along a second direction, which is perpendicular to the first direction. The interdigital transducer further includes a plurality of first dielectric blocks and a plurality of second dielectric blocks. The first dielectric blocks are disposed at the end of the first electrode finger that is opposite to the first busbar and extend to the second busbar. The first dielectric blocks are fixedly connected to the first electrode finger and the second busbar respectively. The second dielectric blocks are disposed at the end of the second electrode finger that is opposite to the second busbar and extend to the first busbar. The second dielectric blocks are fixedly connected to the second electrode finger and the first busbar respectively.

2. The surface acoustic wave resonator of claim 1, wherein, The first dielectric block includes a first dielectric body, which is fixedly connected between the first electrode finger and the second busbar, and the first dielectric body is also connected to the piezoelectric layer; The second dielectric block includes a second dielectric body, which is fixedly connected between the second electrode finger and the first busbar, and the second dielectric body is also connected to the piezoelectric layer.

3. The surface acoustic wave resonator of claim 2, wherein, The first medium has a dimension of 0.15 μm to 3 μm along the first direction, and the second medium has a dimension of 0.15 μm to 3 μm along the first direction.

4. The surface acoustic wave resonator of claim 2, wherein, The first dielectric block further includes a first connector, which is disposed on the surface of the first dielectric block facing away from the piezoelectric layer. The first connector is fixedly connected to the first dielectric block, the first electrode finger, and the second busbar, respectively. The second dielectric block further includes a second connector, which is disposed on the surface of the second dielectric block facing away from the piezoelectric layer. The second connector is fixedly connected to the second dielectric block, the second electrode finger, and the first busbar, respectively.

5. The surface acoustic wave resonator of claim 4, wherein, The first connector has a dimension of 0.45 μm to 24 μm along the first direction, and the second connector has a dimension of 0.45 μm to 24 μm along the first direction.

6. The surface acoustic wave resonator of claim 4, wherein, The first connector has a dimension of 50 to 500 nm along a third direction, and the second connector has a dimension of 50 to 500 nm along the third direction, which is perpendicular to the first direction and the second direction, respectively.

7. The surface acoustic wave resonator of claim 4, wherein, The first dielectric block further includes a first insert and a second insert. The first insert and the second insert are fixedly connected to the surface of the first connector facing the first dielectric body. The first insert and the second insert are located on opposite sides of the first dielectric body along the first direction. The first insert and the second insert are spaced apart from the first dielectric body. The first insert is embedded in the first electrode finger, and the second insert is embedded in the second busbar. The second dielectric block further includes a third embedding and a fourth embedding. The third embedding and the fourth embedding are fixedly connected to the surface of the second connector facing the second dielectric body. The third embedding and the fourth embedding are located on opposite sides of the second dielectric body along the first direction. The third embedding and the fourth embedding are spaced apart from the second dielectric body. The third embedding is embedded in the second electrode finger, and the fourth embedding is embedded in the first busbar.

8. The surface acoustic wave resonator of claim 7, wherein, The dimensions of the first embedding and the second embedding along the first direction are both 0.15 μm to 3 μm; The dimensions of the third and fourth embeddings along the second direction are both 0.15µm to 3µm.

9. The surface acoustic wave resonator according to any one of claims 1 to 8, wherein Multiple first medium blocks are spaced apart from each other, and multiple second medium blocks are spaced apart from each other; or, Multiple first medium blocks are connected sequentially along the second direction, and multiple second medium blocks are connected sequentially along the second direction.

10. The surface acoustic wave resonator according to any one of claims 1 to 8, wherein The interdigital transducer further includes a third busbar and a fourth busbar. The third busbar is disposed on the side of the first busbar opposite to the second busbar and is spaced apart from the first busbar. The fourth busbar is disposed on the side of the second busbar opposite to the first busbar and is spaced apart from the second busbar. The interdigitated transducer further includes a plurality of first connecting fingers and a plurality of second connecting fingers, wherein the first connecting fingers are fixedly connected between the first busbar and the third busbar, and the second connecting fingers are fixedly connected between the second busbar and the fourth busbar.

11. A surface acoustic wave resonator, characterized by, The device includes a piezoelectric layer and an interdigital transducer. The interdigital transducer is disposed on a surface of the piezoelectric layer. The interdigital transducer includes a first busbar, a second busbar, a plurality of first electrode fingers, a plurality of second electrode fingers, a plurality of first dummy fingers, and a plurality of second dummy fingers. The first busbar and the second busbar are arranged along a first direction and spaced apart. The plurality of first electrode fingers are connected to the first busbar and extend towards the second busbar. The first electrode fingers are spaced apart from the second busbar. The plurality of second electrode fingers are connected to the second busbar and extend towards the first busbar. The second electrode fingers are spaced apart from the first busbar. The plurality of first electrode fingers and the plurality of second electrode fingers are arranged alternately and spaced apart along a second direction, which is perpendicular to the first direction. The first spur finger is disposed at the end of the first electrode finger facing away from the first bus bar, the first spur finger is spaced apart from the first electrode finger, and the first spur finger is connected to the second bus bar; the second spur finger is disposed at the end of the second electrode finger facing away from the second bus bar, the second spur finger is spaced apart from the second electrode finger, and the second spur finger is connected to the first bus bar. The interdigital transducer further includes a plurality of first dielectric blocks and a plurality of second dielectric blocks. The first dielectric blocks are disposed at the end of the first electrode finger that is opposite to the first busbar and extend to the first dummy finger. The first dielectric blocks are fixedly connected to the first electrode finger and the first dummy finger respectively. The second dielectric blocks are disposed at the end of the second electrode finger that is opposite to the second busbar and extend to the second dummy finger. The second dielectric blocks are fixedly connected to the second electrode finger and the second dummy finger respectively.

12. The surface acoustic wave resonator of claim 11, wherein, The first dielectric block includes a first dielectric body, which is fixedly connected between the first electrode finger and the first dummy finger, and the first dielectric body is also connected to the piezoelectric layer; The second dielectric block includes a second dielectric body, which is fixedly connected between the second electrode finger and the second dummy finger, and is also connected to the piezoelectric layer.

13. The surface acoustic wave resonator of claim 12, wherein, The first dielectric block further includes a first connector, which is disposed on the surface of the first dielectric block facing away from the piezoelectric layer. The first connector is fixedly connected to the first dielectric block, the first electrode finger, and the first dummy finger, respectively. The second dielectric block further includes a second connector, which is disposed on the surface of the second dielectric block facing away from the piezoelectric layer. The second connector is fixedly connected to the second dielectric block, the second electrode finger, and the second dummy finger, respectively.

14. The surface acoustic wave resonator of claim 13, wherein, The first dielectric block further includes a first insert and a second insert. The first insert and the second insert are fixedly connected to the surface of the first connector facing the first dielectric body. The first insert and the second insert are located on opposite sides of the first dielectric body along the first direction. The first insert and the second insert are spaced apart from the first dielectric body. The first insert is embedded in the first electrode finger, and the second insert is embedded in the first dummy finger. The second dielectric block further includes a third embedding and a fourth embedding. The third embedding and the fourth embedding are fixedly connected to the surface of the second connector facing the second dielectric body. The third embedding and the fourth embedding are located on opposite sides of the second dielectric body along the first direction. The third embedding and the fourth embedding are spaced apart from the second dielectric body. The third embedding is embedded in the second electrode finger, and the fourth embedding is embedded in the second pseudo finger.

15. A filter, characterized by It includes a plurality of surface acoustic wave resonators as described in any one of claims 1-14, wherein the plurality of surface acoustic wave resonators are electrically connected.

16. A radio frequency front end module, comprising: It includes an amplifier and a filter as described in claim 15, wherein the amplifier is electrically connected to the filter.

17. An electronic device, comprising: The radio frequency front end module as claimed in claim 16, wherein the radio frequency front end module is disposed within the housing.

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