Interdigital transducer structure, surface acoustic wave transducer structure and preparation method thereof

Abstract

The invention relates to an interdigital transducer structure, a surface acoustic wave transducer structure and a preparation method thereof. The interdigital transducer structure comprises an interdigital layer, an insulating medium layer and an electrode layer. The interdigital layer comprises a first finger strip part and a second finger strip part, the first finger strip part comprises a plurality of first finger strips which are arranged in the first direction at intervals, and the second finger strip part comprises a plurality of second finger strips which are arranged in the first direction at intervals; the insulating dielectric layer comprises a first dielectric part and a second dielectric part which are arranged in the second direction, the first dielectric part covers part of the first finger strips, close to the overlapping area, of the first extension area, and the second dielectric part covers part of the second finger strips, close to the overlapping area, of the second extension area; the electrode layer comprises a first electrode and a second electrode which are arranged in the second direction, the first electrode at least covers part of the first finger strips located in the first extension area and part of the area of the first medium part, and the second electrode at least covers part of the second finger strips located in the second extension area and part of the area of the second medium part.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to an interdigital transducer structure, a surface acoustic wave transducer structure and a preparation method thereof. Background Art

[0002] As the level of mobile communication technology continues to improve, the number of communication frequency bands has also increased dramatically. With the development of 5G communication technology, mobile terminals must have wireless access to multiple frequency bands of 2G, 3G and 4G, and also process signals such as WiFi, Bluetooth and GPS receivers, which means that the number of surface acoustic wave filters in mobile terminals can reach up to 70. Therefore, how to miniaturize surface acoustic wave filters for mobile communications is an urgent problem to be solved. Summary of the invention

[0003] Based on this, it is necessary to provide an IDT structure, a SAW filter and a preparation method thereof to address the problem of large volume of SAW filters and IDT structures in the prior art.

[0004] In order to achieve the above object, on the one hand, the present invention provides an interdigital transducer structure, comprising:

[0005] The interdigital layer comprises a first finger portion and a second finger portion, wherein the first finger portion comprises a plurality of first fingers arranged and spaced apart in a first direction, and the second finger portion comprises a plurality of second fingers arranged and spaced apart in the first direction, and the plurality of first fingers and the plurality of second fingers are spaced apart from each other and staggered; the interdigital layer comprises an overlapping region, a first extension region and a second extension region, wherein the first extension region and the second extension region are respectively arranged on both sides of the overlapping region along a second direction, wherein the first finger portion and the second finger portion overlap in the overlapping region, wherein the first extension region comprises a portion of the first finger portion extending out of the overlapping region in the second direction, and the second extension region comprises a portion of the second finger portion extending out of the overlapping region in the second direction, and the second direction is perpendicular to the first direction;

[0006] an insulating dielectric layer, comprising a first dielectric portion and a second dielectric portion arranged along the second direction, wherein the first dielectric portion covers a portion of the first fingers in the first extension region close to the overlapping region, and the second dielectric portion covers a portion of the second fingers in the second extension region close to the overlapping region;

[0007] The electrode layer includes a first electrode and a second electrode arranged along the second direction, the first electrode at least covers a portion of the first fingers located in the first extension area and a portion of the first dielectric portion, and the second electrode at least covers a portion of the second fingers located in the second extension area and a portion of the second dielectric portion.

[0008] In one embodiment, the first dielectric portion exposes the gap between two adjacent fingers, and / or the second dielectric portion exposes the gap between two adjacent fingers.

[0009] In one embodiment, the first dielectric portion further covers an end portion of the second finger near the first extension region, and / or the second dielectric portion further covers an end portion of the first finger near the second extension region.

[0010] In one embodiment, the first electrode covers a top region of the first dielectric portion and exposes a side wall of the first dielectric portion facing the second dielectric portion, and / or the second electrode covers a top region of the second dielectric portion and exposes a side wall of the second dielectric portion facing the first dielectric portion.

[0011] In one embodiment, in the second direction, the first electrode further exposes a portion of the top surface of the first dielectric portion close to the second dielectric portion, and the second electrode further exposes a portion of the top surface of the second dielectric portion close to the first dielectric portion.

[0012] In one embodiment, the electrode layer includes a first bump, the first bump is connected to the first electrode, and the first bump protrudes relative to the first electrode toward a side away from the second electrode;

[0013] and / or,

[0014] The electrode layer includes a second bump, the second bump is connected to the second electrode, and the second bump protrudes relative to the second electrode toward a side away from the first electrode.

[0015] Alternatively, holes are provided in the first electrode and / or the second electrode.

[0016] In another aspect, the present invention provides a surface acoustic wave transducer structure, which comprises a substrate and the aforementioned interdigital transducer structure.

[0017] Based on the same invention, the present invention also provides a method for preparing a surface acoustic wave transducer structure, comprising the following steps:

[0018] providing a substrate;

[0019] An interdigital layer is formed on the substrate, the interdigital layer comprising a first finger portion and a second finger portion, the first finger portion comprising a plurality of first fingers arranged and spaced apart along a first direction, the second finger portion comprising a plurality of second fingers arranged and spaced apart along the first direction, the plurality of first fingers and the plurality of second fingers being spaced apart and staggered from each other; the interdigital layer comprises an overlapping region, a first extension region and a second extension region, the first extension region and the second extension region being respectively arranged on both sides of the overlapping region along a second direction, the first finger portion and the second finger portion overlapping in the overlapping region, the first extension region comprising a portion of the first finger portion extending out of the overlapping region in the second direction, the second extension region comprising a portion of the second finger portion extending out of the overlapping region in the second direction, and the second direction is perpendicular to the first direction;

[0020] forming an insulating dielectric layer on the interdigital layer, the insulating dielectric layer comprising a first dielectric portion and a second dielectric portion arranged along the second direction, the first dielectric portion covering a portion of the first fingers in the first extension region close to the overlapping region, and the second dielectric portion covering a portion of the second fingers in the second extension region close to the overlapping region;

[0021] An electrode layer is formed on the insulating dielectric layer, the electrode layer comprising a first electrode and a second electrode arranged along the second direction, the first electrode at least covers a portion of the first fingers located in the first extension area and a portion of the first dielectric portion, and the second electrode at least covers a portion of the second fingers located in the second extension area and a portion of the second dielectric portion.

[0022] In one embodiment, forming an insulating dielectric layer on the interdigital layer includes:

[0023] forming an insulating material layer on the interdigital layer;

[0024] forming a first patterned photoresist layer on the insulating material layer;

[0025] Based on the first patterned photoresist layer, the insulating material layer is etched to form the first dielectric portion and the second dielectric portion arranged along the second direction, wherein the first dielectric portion also covers the first end of the second finger, and the second dielectric portion also covers the second end of the first finger;

[0026] The step of forming an electrode layer on the insulating dielectric layer comprises:

[0027] forming an electrode material layer on the insulating dielectric layer;

[0028] forming a second patterned photoresist layer on the electrode material layer;

[0029] Based on the second patterned photoresist layer, the electrode material layer is etched to form the first electrode and the second electrode, wherein the first electrode further exposes the side wall of the first dielectric portion facing the second dielectric portion, and the second electrode further exposes the side wall of the second dielectric portion facing the first dielectric portion.

[0030] In one embodiment, the electrode layer further includes a first bump and / or a second bump, the first bump is connected to the first electrode, the second bump is connected to the second electrode, and the first bump and / or the second bump are formed while etching the electrode material layer based on the second patterned photoresist layer to form the first electrode and the second electrode, the first bump protrudes relative to the first electrode to a side away from the second electrode, or the second bump protrudes relative to the second electrode to a side away from the first electrode;

[0031] Alternatively, the electrode layer further includes holes, and the electrode material layer is etched based on the second patterned photoresist layer to form the first electrode and the second electrode, and holes are formed in the first electrode and the second electrode at the same time.

[0032] The interdigital transducer structure of the present invention and the preparation method thereof have the following beneficial effects: by arranging an insulating dielectric layer between the interdigital layer and the electrode layer, the electrode layer can be stacked on the interdigital layer. Moreover, the electrode layer covers the top and side walls of the insulating dielectric layer to form a three-dimensional interdigital transducer structure, saving the chip area occupied by the interdigital transducer structure. The interdigital transducer structure is applied to the surface acoustic wave transducer structure, thereby reducing the volume of the surface acoustic wave transducer structure and meeting the demand for miniaturization of the surface acoustic wave filter. Moreover, when the interdigital transducer structure of the present invention is applied to a substrate such as a piezoelectric single crystal film on an insulator, transverse mode suppression can also be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 is a flow chart of a method for preparing a surface acoustic wave transducer structure provided in an embodiment;

[0035] Figure 2 is a schematic diagram of a substrate provided in an embodiment;

[0036] Figure 3is a schematic diagram of a photoresist material layer provided in an embodiment;

[0037] Figure 4 is a schematic diagram of an interdigitated metal film layer provided in an embodiment;

[0038] Figure 5 A schematic diagram of an interdigital layer provided in an embodiment;

[0039] Figure 6a A top view of an interdigital layer provided in one embodiment;

[0040] Figure 6b A schematic diagram of an overlapping area, a first extension area, and a second extension area provided in one embodiment;

[0041] Figure 7a is a schematic diagram of an insulating dielectric layer provided in an embodiment;

[0042] Figure 7b A schematic diagram of an insulating dielectric layer provided in another embodiment;

[0043] Figure 7c A schematic diagram of an insulating dielectric layer provided in another embodiment;

[0044] Figure 7d A schematic diagram of an insulating dielectric layer provided in another embodiment;

[0045] Figure 8a is a schematic diagram of an electrode layer provided in an embodiment;

[0046] Figure 8b A schematic diagram of an electrode layer provided in another embodiment;

[0047] Fig. 9 It is a schematic diagram of the structure of an interdigital transducer in the related art provided in an embodiment;

[0048] Fig.10 is a cross-sectional view of an interdigital transducer structure provided in an embodiment;

[0049] Fig.11 is a schematic diagram of a patterned electrode layer provided in an embodiment;

[0050] Fig.12 is a schematic diagram of a patterned electrode layer provided in another embodiment;

[0051] Fig.13 A graph showing an admittance response curve of a surface acoustic wave transducer structure in the related art provided in an embodiment;

[0052] Fig.14 is a graph showing the structural admittance response of a surface acoustic wave transducer in the present application provided in one embodiment;

[0053] Fig.15 is a schematic diagram of an equivalent circuit of a surface acoustic wave transducer structure provided in an embodiment;

[0054] Fig.16 It is a comparison diagram of resonance curves of a surface wave transducer structure provided in one embodiment.

[0055] Description of reference numerals:

[0056] Surface acoustic wave transducer structure-10; substrate-11; interdigital transducer structure-12; interdigital layer-121; interdigital metal film layer-1210; first finger portion-1211; first finger-1211a; second finger portion-1212; second finger-1212a; insulating dielectric layer-122; first dielectric portion-1221; second dielectric portion-1222; electrode layer-123; first electrode-1231; second electrode-1232; hole-124; first bump-125; second bump-126; photoresist material layer-20; photoresist layer-21. DETAILED DESCRIPTION

[0057] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0059] It should be understood that when an element or layer is referred to as being "on," "adjacent to," or "connected to" another element or layer, it may be directly on, adjacent to, or connected to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," or "directly connected to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, and layers, these elements, components, regions, and layers should not be limited by these terms. These terms are merely used to distinguish one element, component, region, or layer from another element, component, region, or layer. Therefore, the first element, component, region, or layer discussed below may be represented as the second element, component, region, or layer without departing from the teachings of the present invention.

[0060] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0061] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0062] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic representations of idealized embodiments (and intermediate structures) of the invention, and variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are contemplated. Thus, embodiments of the invention should not be limited to the particular shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. The regions shown in the figures are schematic in nature, and their shapes do not represent the actual shapes of the regions of the device, and do not limit the scope of the invention.

[0063] See also Figure 1 The present invention provides a method for preparing a surface acoustic wave transducer structure 10. The surface acoustic wave transducer structure 10 includes a substrate 11 and an interdigital transducer structure 12. The method for preparing the surface acoustic wave transducer structure 10 includes the following steps:

[0064] Step S100: providing a substrate 11 .

[0065] Step S200: forming an interdigitated finger layer 121 on the substrate 11, the interdigitated finger layer comprising a first finger portion 1211 and a second finger portion 1212, the first finger portion 1211 comprising a plurality of first fingers 1211a arranged and spaced apart along a first direction, the second finger portion 1212 comprising a plurality of second fingers 1212a arranged and spaced apart along the first direction, the plurality of first fingers 1211a and the plurality of second fingers 1212a being spaced apart and staggered from each other; the interdigitated finger layer 121 has an overlapping region, a first extension region and a second extension region, the first extension region and the second extension region being respectively arranged on both sides of the overlapping region along the second direction, the first finger portion 1211 and the second finger portion 1212 overlapping in the overlapping region, the first extension region comprising a portion of the first finger portion 1211a extending out of the overlapping region in the second direction, the second extension region comprising a portion of the second finger portion 1212a extending out of the overlapping region in the second direction, and the second direction is perpendicular to the first direction.

[0066] Step S300: forming an insulating dielectric layer 122 on the interdigitated layer 121, the insulating dielectric layer 122 comprising a first dielectric portion 1221 and a second dielectric portion 1222 arranged along the second direction, the first dielectric portion 1221 covering a portion of the first finger 1211a in the first extension region close to the overlapping region, and the second dielectric portion 1222 covering a portion of the second finger 1212a in the second extension region close to the overlapping region.

[0067] Step S400: An electrode layer 123 is formed on the insulating dielectric layer 122, wherein the electrode layer 123 includes a first electrode 1231 and a second electrode 1232 arranged along a second direction, wherein the first electrode 1231 at least covers a portion of the first finger 1211a in the first extension region and a portion of the first dielectric portion 1221, and the second electrode 1232 at least covers a portion of the second finger 1212a in the second extension region and a portion of the second dielectric portion 1222.

[0068] In step S100, the surface acoustic wave transducer 10 structure includes a substrate 11 and an interdigital transducer structure 12 disposed on the substrate 11. The interdigital transducer structure 12 in this embodiment can be applied not only to conventional surface acoustic wave filters, but also to surface acoustic wave filter structures (temperature compensated SAW, TC-SAW) on piezoelectric single crystal thin film structures on insulators (Piezo-On-Insulator, POI) wafers and on temperature compensated wafers. Of course, it can also be applied to other structures with thick film covering layers, including but not limited to XBAR structures.

[0069] A conductive structure or an interconnection structure may be disposed on the substrate 11 and connected to the IDT structure 12 .

[0070] See also Figure 2The substrate 11 may include a piezoelectric material substrate. As an example, the material of the piezoelectric material substrate may include lithium tantalate (LiTaO 3 ), lithium niobate (LiNbO 3 ) or quartz.

[0071] In step S200, refer to Figure 3 When forming the interdigital layer 121 on the substrate 11, a photoresist material layer 20 may be formed on the substrate 11 first. The photoresist material layer 20 may be a single layer or multiple layers. The photoresist material layer 20 may also protect the upper surface of the substrate 11 from being contaminated.

[0072] See also Figure 4 The photoresist layer material 20 is subjected to exposure, development, baking and other process treatments to form a photoresist layer 21. The photoresist layer 21 exposes a portion of the upper surface of the substrate 11. The side surface of the photoresist layer 21 may be in an inverted trapezoid or a rectangle.

[0073] Then, an interdigitated metal film layer 1210 can be formed on the upper surface of the photoresist layer 21 and the upper surface of the exposed substrate 11 by electron beam evaporation, magnetron sputtering, etc. The material of the interdigitated metal film layer 1210 can be titanium, cadmium, copper, silver, aluminum or alloys.

[0074] As an example, when the side surface of the photoresist layer 21 is inverted trapezoidal, the side surface of the interdigitated metal film layer 1210 formed on the exposed upper surface of the substrate 11 may be trapezoidal. This embodiment does not specifically limit the side surface shape of the interdigitated metal film layer 1210.

[0075] Finally, see Figure 5 The photoresist layer 21 and the interdigitated metal film layer 1210 on the upper surface of the photoresist layer 21 may be removed by a wet stripping process, and the interdigitated metal film layer 1210 on the upper surface of the substrate 11 may be retained to form an interdigitated layer 121 .

[0076] For details, please refer to Figure 6a The interdigital layer 121 includes a first finger portion 1211 and a second finger portion 1212. The first finger portion 1211 includes a plurality of first fingers 1211a arranged and spaced apart along a first direction, and the second finger portion 1212 includes a plurality of second fingers 1212a arranged and spaced apart along the first direction. As an example, the first direction may be an X direction.

[0077] The period of the IDT may be the length from the center of a first finger 1211a to the center of a second finger 1212a adjacent thereto, and the length is 1 / 2λ of the wavelength. As an example, the period of the IDT may be controlled within the range of 0.5um to 20um. The above data are only examples, and in actual embodiments, the period of the IDT is not limited to the above data.

[0078] The first finger 1211a and the second finger 1212a both include a first end and a second end disposed opposite to each other in a second direction. Moreover, the second direction intersects with the first direction. As an example, the second direction may be a Y direction, and the first direction may be perpendicular to the second direction.

[0079] The second direction may include an opposite positive direction and a negative direction. As an example, the Y1 direction may be directed in a positive direction, and the Y2 direction may be directed in a negative direction.

[0080] In the second direction, the first end of the first finger 1211a protrudes toward the positive direction of the second direction relative to the first end of the second finger 1212a, and the second end of the second finger 1212a protrudes toward the negative direction of the second direction relative to the second end of the first finger 1211a.

[0081] At this time, see Figure 6b The interdigital layer 121 can be divided into an overlapping area, a first extension area and a second extension area, and the first extension area and the second extension area are respectively arranged on both sides of the overlapping area along the second direction. The overlapping portion of the first finger 1211a and the second finger 1212a is the overlapping area, the first extension area includes a portion of the first finger portion 1211a extending out of the overlapping area in the second direction, and the second extension area includes a portion of the second finger portion 1212a extending out of the overlapping area in the second direction.

[0082] It can be understood that the first end of the first finger 1211a can be located in the first extension area, and the second end of the second finger 1212a can be located in the second extension area.

[0083] In step S300, refer to Figures 7a to 7d The insulating dielectric layer 122 may be formed on the interdigital layer 121 by evaporation or sputtering. The insulating dielectric layer 122 may be made of silicon dioxide, silicon nitride, polyimide, aluminum oxide, tantalum pentoxide, chromium oxide, titanium oxide, and other materials.

[0084] The insulating dielectric layer 122 includes a first dielectric portion 1221 and a second dielectric portion 1222 arranged along the second direction.

[0085] See also Figure 7bThe first dielectric portion 1221 extends along the first direction to cover a portion of the first finger 1211a in the first extension region near the overlapping region. Meanwhile, the first dielectric portion 1221 exposes the first end of the first finger 1211a.

[0086] Likewise, the second dielectric portion 1222 may extend along the first direction to cover a portion of the second finger 1212a in the second extension region close to the overlapping region, and at the same time, the second dielectric portion 1222 may expose the second end of the second finger 1212a.

[0087] As an example, the thickness of the first dielectric portion 1221 and the second dielectric portion 1222 may be between 5 nm and 1000 nm. For example, the thickness of the first dielectric portion 1221 and the second dielectric portion 1222 may be about 25 nm. The length of the first dielectric portion 1221 and the second dielectric portion 1222 along the Y direction may be between 0.1 and 5 times the wavelength. For example, the length of the first dielectric portion 1221 and the second dielectric portion 1222 along the Y direction may be about 0.7 times the wavelength. The above data are only examples. In actual embodiments, the thickness and length of the first dielectric portion 1221 and the second dielectric portion 1222 are not limited to the above data. For example, please refer to Figure 7b In the Y direction, the first dielectric portion 1221 may extend from the first extension area to the overlapping area. Meanwhile, the second dielectric portion 1222 may extend from the second extension area to the overlapping area. In this embodiment, the lengths of the first dielectric portion 1221 and the second dielectric portion 1222 in the Y direction are not limited.

[0088] In step S400, refer to Figure 8a and Figure 8b The electrode layer 123 may be formed on the insulating dielectric layer 122 by using a process such as evaporation or sputtering. The electrode layer 123 is used to realize electrical connection between the plurality of first fingers 1211a and / or the second fingers 1212a.

[0089] The electrode layer 123 includes a first electrode 1231 and a second electrode 1232 arranged along the second direction. The first electrode 1231 covers at least part of the first finger 1211 located in the first extension area. At this time, the first electrode 1231 can realize that the first electrode 1231 is electrically connected to each first finger 1211a. The first electrode 1231 can also cover a part of the first dielectric portion 1221. For example, the first electrode 1231 covers the top surface of the first dielectric portion 1221 and the side wall of the first dielectric portion 1221 away from the second electrode 1232.

[0090] Similarly, the second electrode 1232 covers at least part of the second fingers 1212a of the second extension region. In this case, the second electrode 1232 can realize that the second electrode 1232 is electrically connected to each second finger 1212a. The second electrode 1232 can also cover part of the second dielectric portion 1222. For example, the second electrode 1232 covers the top surface of the second dielectric portion 1222 and the side wall of the second dielectric portion 1222 away from the first electrode 1231.

[0091] In the first direction (eg, X direction), the electrode layer 123 may completely cover the corresponding insulating dielectric layer 122 or have the same length as the insulating dielectric layer 122. Of course, the electrode layer 123 may also only cover a portion of the insulating dielectric layer 122.

[0092] As an example, the thickness of the electrode layer 123 may be between 70 nm and 20000 nm. For example, the thickness of the electrode layer 123 may be 150 nm. The length of the electrode layer 123 may be between 0.1 pitch and 8 pitch. For example, the length of the electrode layer 123 is 1.5 pitch.

[0093] For related technologies, see Fig. 9 The structure of the interdigital transducer is usually planar. It is understandable that the electrode layer and the interdigital layer are usually on the same plane. Moreover, the interdigital layer often has a true finger area, a false finger area, and a gap area. This makes the interdigital transducer structure have a large volume, and thus the surface acoustic wave transducer structure also has a large volume, which is not conducive to the integration of multiple surface acoustic wave transducer structures.

[0094] In this embodiment, first, by forming alternately protruding first fingers 1211a and second fingers 1212a, the first electrodes 1231 and second electrodes 1232 formed subsequently can contact the corresponding fingers respectively, so as to achieve the purpose of electrically connecting the first electrodes 1231 and the second electrodes 1232 to the corresponding fingers. This can make the interdigital transducer structure 12 not set with a dummy finger area and a gap area, thereby reducing the volume occupied by the dummy finger area and the gap area.

[0095] Second, see Fig.10 An insulating dielectric layer 122 is formed between the interdigital layer 121 and the electrode layer 123, thereby forming a planar capacitor structure. The planar capacitor structure not only allows the interdigital transducer structure 12 to be free of gap regions, but also enhances the capacitance of the surface acoustic wave transducer structure 10 and improves the rectangularity of the surface acoustic wave transducer structure 10.

[0096] Moreover, the electrode layer 123 covers the top and side walls of the insulating dielectric layer 122 to form a three-dimensional IDT structure 12 , saving the chip area occupied by the IDT structure 12 and thereby improving the integration of the IDT structure 12 and the SAW transducer structure 10 .

[0097] Finally, the first electrode 1231 can cover the first end of the first finger 1211a, and the second electrode 1232 can cover the second end of the second finger 1212a. Compared with the related art, the contact area between the electrode layer 123 and the corresponding finger is increased, which enhances the control ability of the electrode layer 123 on the corresponding finger.

[0098] In one embodiment, step S300 includes:

[0099] Step S310 : forming an insulating material layer on the interdigital layer 121 .

[0100] Step S320 : forming a first patterned photoresist layer on the insulating material layer 122 .

[0101] Step S330: Based on the first patterned photoresist layer, the insulating material layer is etched to form a first dielectric portion 1221 and a second dielectric portion 1222 arranged along the second direction, wherein the first dielectric portion 1221 also covers the first end of the second finger 1212a, and the second dielectric portion 1222 also covers the second end of the first finger 1211a.

[0102] Meanwhile, step S400 includes:

[0103] Step S410 : forming an electrode material layer on the insulating dielectric layer 122 .

[0104] Step S420: forming a second patterned photoresist layer on the electrode material layer.

[0105] Step S430: Based on the second patterned photoresist layer, the electrode material layer is etched to form a first electrode 1231 and a second electrode 1232 , wherein the first electrode 1231 also exposes the side wall of the first dielectric portion 1221 facing the second dielectric portion 1222 , and the second electrode 1232 also exposes the side wall of the second dielectric portion 1222 facing the first dielectric portion 1221 .

[0106] In step S310 , an insulating material layer may be deposited entirely on the interdigital layer 121 .

[0107] In step S320 , the first patterned photoresist layer may expose the middle portion of the insulating material layer and cover both sides of the insulating material layer.

[0108] In step S330 , after steps such as exposure and development, the insulating material layer is etched to form a first dielectric portion 1221 and a second dielectric portion 1222 arranged along the second direction.

[0109] See also Figure 7a and Fig.10The first dielectric portion 1221 is located on the top surface of each first finger 1211a close to the first end, and the first end of the second finger 1212a. The first dielectric portion 1221 can cover the first end of the second finger 1212a. When the first electrode 1231 is subsequently formed on the first dielectric portion 1221, the first dielectric portion 1221, the first electrode 1231 and the second finger 1212a together form a planar capacitor structure.

[0110] The second dielectric portion 1222 is located on the top surface of each second finger 1212a close to the second end, and the second end of the first finger 1211a. Similarly, the second dielectric portion 1222 can cover the second end of the first finger 1211a. When the second electrode 1232 is subsequently formed on the second dielectric portion 1222, the second dielectric portion 1222, the second electrode 1232 and the first finger 1211a together form a planar capacitor structure.

[0111] In one embodiment, see Figure 7c The first dielectric portion 1221 exposes the finger gaps between adjacent fingers (eg, adjacent first fingers 1211a), and the second dielectric portion 1222 exposes the finger gaps between adjacent fingers (eg, adjacent second fingers 1212a). The finger gaps may be filled with electrode material or insulating material in subsequent steps.

[0112] In another embodiment, see Figure 7d The first dielectric portion 1221 may only cover a portion of each first finger 1211a near the overlapping region, and the second dielectric portion 1222 may only cover a portion of each second finger 1212a near the overlapping region.

[0113] Those skilled in the art should know that the first dielectric portion 1221 and the second dielectric portion 1222 may be formed by various etching methods.

[0114] In step S410 , an electrode material layer may be deposited entirely on the insulating dielectric layer 122 .

[0115] In step S420, the second patterned photoresist layer may expose the middle of the electrode material layer and cover both sides of the electrode material layer.

[0116] In step S430 , after steps such as exposure and development, the electrode material layer is etched to form a first electrode 1231 and a second electrode 1232 .

[0117] See also Figure 8a , Figure 8b and Fig.10, the first electrode 1231 covers the first end of each first finger 1211a to achieve electrical connection of the first end of each first finger 1211a. The first electrode 1231 may also cover the top surface of the first dielectric portion 1221 and the side wall of the first dielectric portion 1221 away from the second electrode 1232. In this case, the first electrode 1231 may partially cover the first dielectric portion 1221 to form a planar capacitor structure.

[0118] The second electrode 1232 covers the second end of each second finger 1212a to achieve electrical connection of the second end of each second finger 1212a. The second electrode 1232 may also cover the top surface of the second dielectric portion 1222 and the side wall of the second dielectric portion 1222 away from the first electrode 1231. Similarly, the second electrode 1232 may partially cover the second dielectric portion 1222 to form a planar capacitor structure.

[0119] In this embodiment, the first electrode 1231 may completely cover the top surface of the first dielectric portion 1221, or may cover a portion of the top surface of the first dielectric portion 1221, exposing the top surface of the first dielectric portion 1221 close to the second dielectric portion 1222. Similarly, the second electrode 1232 may completely cover the top surface of the second dielectric portion 1222, or may cover a portion of the top surface of the second dielectric portion 1222, exposing the top surface of the second dielectric portion 1222 close to the first dielectric portion 1221.

[0120] In another embodiment, see Figure 8b The first electrode 1231 may be connected only to the first finger 1211a, and may be spaced apart from the second finger 1212a. Meanwhile, the second electrode 1232 may be connected only to the second finger 1212a, and may be spaced apart from the first finger 1211a.

[0121] After step S400 , if there is a gap between the electrode layer 123 and the insulating dielectric layer 122 , the gap may be filled with the same material as the insulating dielectric layer 122 , or may not be processed.

[0122] In one embodiment, see Fig.11 and Fig.12 The electrode layer 123 may include a patterned electrode layer. For example, the electrode layer 123 further includes a hole 124 , a first bump 125 and / or a second bump 126 .

[0123] See also Fig.11 The hole 124 may extend from the surface of the electrode layer 123 to the insulating dielectric layer 122. The shape of the hole 124 includes but is not limited to a "convex" shape, a semicircle, a strip, etc. The hole 124 may achieve shear wave mode suppression.

[0124] See also Fig.12, the first bump 125 may protrude relative to the first electrode 1231 toward a side away from the second electrode 1232, and the first bump 125 is connected to the first electrode 1231. Similarly, the second bump 126 may protrude relative to the second electrode 1232 toward a side away from the first electrode 1231, and the second bump 126 is connected to the second electrode 1232. The first bump 125 and / or the second bump 126 may also achieve shear wave mode suppression.

[0125] The following description is made by taking the electrode layer 123 including the first bump 125 and / or the second bump 126 as an example. In this case, step S400 includes:

[0126] Step S430 : forming an electrode material layer on the insulating dielectric layer 122 .

[0127] Step S431: forming a patterned photoresist layer on the electrode material layer.

[0128] Step S432: Based on the patterned photoresist layer, the electrode material layer is etched to form the first electrode 1231 and the second electrode 1232, and at the same time, the first bump 125 and / or the second bump 126 are formed, the first bump 125 protrudes relative to the first electrode 1231 to a side away from the second electrode 1232, and the first bump 125 is connected to the first electrode 1231. Alternatively, the second bump 126 protrudes relative to the second electrode 1232 to a side away from the first electrode 1231, and the second bump 126 is connected to the second electrode 1232.

[0129] In step S430 , an electrode material layer may be formed entirely on the insulating dielectric layer 122 .

[0130] In step S431 , a patterned photoresist layer is formed on the electrode material layer, and the patterned photoresist layer not only displays the patterns of the first electrode 1231 and the second electrode 1232 , but also displays the patterns of the first bump 125 and / or the second bump 126 .

[0131] In step S432 , based on the patterned photoresist layer, a part of the electrode material layer is removed by dry or wet etching, and the remaining electrode material layer forms the first electrode 1231 and the second electrode 1232 , and also forms the first bump 125 and / or the second bump 126 .

[0132] For example, the dry etching may use any one of reactive ion etching, inductively coupled plasma etching, or high concentration plasma etching.

[0133] When the electrode layer 123 further includes the hole 124, while forming the first electrode 1231 and the second electrode 1232, the hole 124 is also formed in the first electrode 1231 and the second electrode 1232. The formation of the hole 124 is similar to the formation process of the first bump 125 and / or the second bump 126. No further details will be given here.

[0134] In this embodiment, by providing the hole 124 , the first bump 125 and / or the second bump 126 in the electrode layer 123 , shear wave mode suppression is achieved, thereby improving the performance of the IDT structure 12 .

[0135] In addition, the hole 124 , the first bump 125 and / or the second bump 126 may be formed simultaneously with the first electrode 1231 and the second electrode 1232 , thereby improving the preparation efficiency of the electrode layer 123 .

[0136] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0137] Please continue reading Figure 8a and Figure 8b Based on the same inventive concept, in one embodiment, a surface acoustic wave transducer structure 10 is provided. A surface acoustic wave transducer structure 10 includes a substrate 11 and an interdigital transducer structure 12. The interdigital transducer structure 12 includes an interdigital layer 121, an insulating dielectric layer 122 and an electrode layer 123.

[0138] The interdigital layer includes a first finger portion 1211 and a second finger portion 1212. The first finger portion 1211 includes a plurality of first fingers 1211a arranged and spaced apart along a first direction, and the second finger portion 1212 includes a plurality of second fingers 1212a arranged and spaced apart along the first direction. As an example, the first direction may be an X direction.

[0139] The first finger 1211a and the second finger 1212a each include a first end and a second end disposed opposite to each other in a second direction, the second direction intersecting the first direction. As an example, the second direction may be a Y direction, and the first direction and the second direction may be perpendicular.

[0140] In the second direction, the first end of the first finger 1211a protrudes toward the positive direction of the second direction relative to the first end of the second finger 1212a, and the second end of the second finger 1212a protrudes toward the negative direction of the second direction relative to the second end of the first finger 1211a. As an example, the Y1 direction may be directed in the positive direction, and the Y2 direction may be directed in the negative direction.

[0141] For details, please refer to Figure 6b , multiple first finger strips 1211a and multiple second finger strips 1212a are spaced apart from each other and arranged alternately; the interdigitated finger layer 121 has an overlapping area, a first extension area and a second extension area, the first extension area and the second extension area are respectively arranged on both sides of the overlapping area along the second direction, the first finger strip portion 1211 and the second finger strip portion 1212 overlap in the overlapping area, the first extension area includes a portion of the first finger strip portion 1211a extending out of the overlapping area in the second direction, the second extension area includes a portion of the second finger strip portion 1212a extending out of the overlapping area in the second direction, and the second direction is perpendicular to the first direction.

[0142] The insulating dielectric layer 122 includes a first dielectric portion 1221 and a second dielectric portion 1222 arranged along the second direction.

[0143] The first dielectric portion 1221 covers a portion of the first finger strip 1211 a in the first extension region close to the overlapping region, and the second dielectric portion 1222 covers a portion of the second finger strip 1212 a in the second extension region close to the overlapping region.

[0144] The electrode layer 123 includes a first electrode 1231 and a second electrode 1232 arranged along the second direction. The first electrode 1231 at least covers a portion of the first finger 1211a in the first extension region and a portion of the first dielectric portion 1221, and the second electrode 1232 at least covers a portion of the second finger 1212a in the second extension region and a portion of the second dielectric portion 1222.

[0145] In this embodiment, the alternately protruding first fingers 1211a and second fingers 1212a can contact the first electrode 1231 and the second electrode 1232 respectively, so as to achieve the purpose of electrically connecting the first electrode 1231 and the second electrode 1232 to the corresponding fingers. This can reduce the volume occupied by the dummy finger area of ​​the interdigital transducer structure 12.

[0146] Furthermore, an insulating dielectric layer 122 is provided between the interdigital layer 121 and the electrode layer 123 to form a planar capacitor structure that not only reduces the volume occupied by the gap region of the interdigital transducer structure 12 , but also enhances the capacitance of the surface acoustic wave transducer structure 10 .

[0147] Finally, the first electrode 1231 can cover the first end of the first finger 1211a, and the second electrode 1232 can cover the second end of the second finger 1212a. Compared with the related art, the contact area between the electrode layer 123 and the corresponding finger is increased, which enhances the control ability of the electrode layer 123 on the corresponding finger.

[0148] In one embodiment, see Fig.10 , the first dielectric portion 1221 also covers the first end of the second finger 1212a, and the first electrode 1231 covers the top region of the first dielectric portion 1221 and exposes the side wall of the first dielectric portion 1221 facing the second dielectric portion 1222. Similarly, the second dielectric portion 1222 covers the second end of the first finger 1211a, and the second electrode 1232 covers the top region of the second dielectric portion 1222 and exposes the side wall of the second dielectric portion 1222 facing the first dielectric portion 1221.

[0149] In one embodiment, see Figure 8a Those skilled in the art should know that the first finger strip 1211a includes a first true finger, and the second finger strip 1212a includes a second true finger. The first true finger and the second true finger are alternately arranged in the first direction.

[0150] The IDT structure 12 can be divided into a first electrode region, a second finger end region, a true finger region, a first finger end region and a second electrode region in sequence in the second direction.

[0151] The first electrode region is a region formed by a portion of the first end of the first finger 1211a protruding from the second finger 1212a. In this region, the first end of the first finger 1211a contacts the first electrode 1231 to form an electrical connection.

[0152] The second finger end region is a region formed by the portion of the second finger 1212a close to the first end. In this region, the second finger 1212a may be covered with the first dielectric portion 1221, and together with the first electrode 1231, form a planar capacitor structure.

[0153] The true finger area is the area where the first finger strip 1211a and the second finger strip 1212a are exposed. In this area, the conversion of electrical energy and acoustic energy is mainly realized. The first true finger and the second true finger are staggered along the first direction in this area.

[0154] The first finger end region is a region formed by the portion of the first finger 1211a close to the second end. In this region, the first finger 1211a may be covered with the second dielectric portion 1222, and together with the second electrode 1232, form a planar capacitor structure.

[0155] The second electrode region is a region formed by the portion where the second end of the second finger 1212a protrudes from the first finger 1211a. In this region, the second end of the second finger 1212a contacts the second electrode 1232 to form an electrical connection.

[0156] In this embodiment, by providing the first dielectric portion 1221 and the second dielectric portion 1222, the first electrode 1231 and the second electrode 1232 can cover the first finger 1211a and the second finger 1212a to form a three-dimensional IDT structure 12. Compared with the related art, the present embodiment eliminates the dummy finger area and the gap area, thereby reducing the volume of the IDT structure in the related art.

[0157] Of course, in this embodiment, the IDT structure 12 may also include a dummy finger region and a gap region. At this time, the insulating dielectric layer 122 and the electrode layer 123 may sequentially cover the top surface of the dummy finger region.

[0158] In one embodiment, see Figure 7c The first dielectric portion 1221 exposes the gap between two adjacent fingers, and the second dielectric portion 1222 exposes the gap between two adjacent fingers. The gap between the fingers can be filled with electrode material or insulating material in subsequent steps.

[0159] In another embodiment, see Figure 7d The first dielectric portion 1221 may only cover a portion of each first finger 1211a near the overlapping region, and the second dielectric portion 1222 may only cover a portion of each second finger 1212a near the overlapping region.

[0160] In one embodiment, see Fig.11 and Fig.12 The electrode layer 123 further includes a hole 124 , a first bump 125 and / or a second bump 126 .

[0161] The hole 124 may extend from the surface of the electrode layer 123 to the insulating dielectric layer 122. The shape of the hole 124 includes but is not limited to a "convex" shape, a semicircle, a strip, etc. The hole 124 may achieve shear wave mode suppression.

[0162] The first bump 125 may protrude relative to the first electrode 1231 toward a side away from the second electrode 1232, and the first bump 125 is connected to the first electrode 1231. Similarly, the second bump 126 may protrude relative to the second electrode 1232 toward a side away from the first electrode 1231, and the second bump 126 is connected to the second electrode 1232. The first bump 125 and / or the second bump 126 may also achieve shear wave mode suppression.

[0163] The interdigital transducer structure 12 in the above embodiment can be applied not only to conventional surface acoustic wave filters, but also to POI wafers and TC-SAW. Of course, it can also be applied to other structures with thick film covering layers, including but not limited to XBAR structures.

[0164] As an example, when the interdigital transducer structure 12 in the above embodiment is applied to the POI substrate material, the shear wave mode suppression effect can be achieved. For the admittance response curve of the conventional surface acoustic wave transducer structure, please refer to Fig.13 For the admittance response curve of the surface acoustic wave transducer structure 10 in the above embodiment, please refer to Fig.14 Obviously, Fig.13 The curve in is steeper. Fig.14 The middle curve is relatively smooth. The surface acoustic wave transducer structure 10 proposed in this embodiment can better suppress the shear wave mode.

[0165] In another example, the equivalent circuit of a surface acoustic wave transducer can be seen in Fig.15 Among them, C0 represents the capacitance between the transducer electrodes, Lm represents the dynamic inductance, Cm represents the dynamic capacitance, Rm represents the dynamic resistance, R0 represents the loss of the substrate material, and Rs represents the electrode loss.

[0166] Compared with the related art, the surface acoustic wave transducer structure 10 in the above embodiment adds an insulating dielectric layer 122, a finger layer 121, an insulating dielectric layer 122 and an electrode layer 123 to form a planar capacitor structure. Equivalent to the equivalent circuit of the surface acoustic wave transducer, that is, the transducer inter-electrode capacitance C0 becomes larger.

[0167] The increase of the capacitance C0 between the transducer electrodes can move the anti-resonance point of the resonator to the left, thereby improving the rectangularity of the surface acoustic wave transducer structure 10. Fig.16 , the frequency is between 870MHz-880MHz, the anti-resonance point in this embodiment is biased to the left, and the anti-resonance point of the conventional surface acoustic wave transducer structure is biased to the right.

[0168] In the above embodiment, multiple insulating dielectric layers 122 and electrode layers 123 may be stacked to form a multi-layer IDT structure 12 .

[0169] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An interdigital transducer structure, characterized in that: include: The interdigital layer comprises a first finger portion and a second finger portion, wherein the first finger portion comprises a plurality of first fingers arranged and spaced apart along a first direction, and the second finger portion comprises a plurality of second fingers arranged and spaced apart along the first direction, wherein the plurality of first fingers and the plurality of second fingers are spaced apart from each other and staggered; the interdigital layer comprises an overlapping region, a first extension region and a second extension region, wherein the first extension region and the second extension region are respectively arranged on both sides of the overlapping region along a second direction, wherein the first finger portion and the second finger portion overlap in the overlapping region, wherein the first extension region comprises a portion of the first finger portion extending out of the overlapping region in the second direction, and the second extension region comprises a portion of the second finger portion extending out of the overlapping region in the second direction, and wherein the second direction is perpendicular to the first direction; an insulating dielectric layer, comprising a first dielectric portion and a second dielectric portion arranged along the second direction, the first dielectric portion covering a portion of the first fingers in the first extension region close to the overlapping region, and the second dielectric portion covering a portion of the second fingers in the second extension region close to the overlapping region; The electrode layer includes a first electrode and a second electrode arranged along the second direction, the first electrode at least covers a portion of the first fingers located in the first extension area and a portion of the first dielectric portion, and the second electrode at least covers a portion of the second fingers located in the second extension area and a portion of the second dielectric portion.

2. The interdigital transducer structure according to claim 1, characterized in that: The first dielectric portion exposes the gap between two adjacent fingers, and / or the second dielectric portion exposes the gap between two adjacent fingers.

3. The interdigital transducer structure according to claim 1, characterized in that: The first dielectric portion further covers an end portion of the second finger near the first extension region, and / or the second dielectric portion further covers an end portion of the first finger near the second extension region.

4. The IDT structure according to claim 1, characterized in that: The first electrode covers a top region of the first dielectric portion and exposes a side wall of the first dielectric portion facing the second dielectric portion, and / or the second electrode covers a top region of the second dielectric portion and exposes a side wall of the second dielectric portion facing the first dielectric portion.

5. The IDT structure according to claim 1, characterized in that: In the second direction, the first electrode further exposes a portion of the top surface of the first dielectric portion close to the second dielectric portion, and the second electrode further exposes a portion of the top surface of the second dielectric portion close to the first dielectric portion.

6. The interdigital transducer structure according to claim 1, characterized in that: The electrode layer further includes a first bump, the first bump is connected to the first electrode, and the first bump protrudes relative to the first electrode toward a side away from the second electrode; and / or, The electrode layer further includes a second bump, the second bump is connected to the second electrode, and the second bump protrudes relative to the second electrode toward a side away from the first electrode; Alternatively, holes are provided in the first electrode and / or the second electrode.

7. A surface acoustic wave transducer structure, characterized in that: The surface acoustic wave transducer structure comprises a substrate and an interdigital transducer structure as claimed in any one of claims 1 to 6.

8. A method for preparing a surface acoustic wave transducer structure, characterized in that: The steps include: providing a substrate; An interdigital layer is formed on the substrate, the interdigital layer comprising a first finger portion and a second finger portion, the first finger portion comprising a plurality of first fingers arranged and spaced apart along a first direction, the second finger portion comprising a plurality of second fingers arranged and spaced apart along the first direction, the plurality of first fingers and the plurality of second fingers being spaced apart and staggered from each other; the interdigital layer comprises an overlapping region, a first extension region and a second extension region, the first extension region and the second extension region being respectively arranged on both sides of the overlapping region along a second direction, the first finger portion and the second finger portion overlapping in the overlapping region, the first extension region comprising a portion of the first finger portion extending out of the overlapping region in the second direction, the second extension region comprising a portion of the second finger portion extending out of the overlapping region in the second direction, and the second direction is perpendicular to the first direction; forming an insulating dielectric layer on the interdigital layer, the insulating dielectric layer comprising a first dielectric portion and a second dielectric portion arranged along the second direction, the first dielectric portion covering a portion of the first fingers in the first extension region close to the overlapping region, and the second dielectric portion covering a portion of the second fingers in the second extension region close to the overlapping region; An electrode layer is formed on the insulating dielectric layer, the electrode layer comprising a first electrode and a second electrode arranged along the second direction, the first electrode at least covers a portion of the first fingers located in the first extension area and a portion of the first dielectric portion, and the second electrode at least covers a portion of the second fingers located in the second extension area and a portion of the second dielectric portion.

9. The method for preparing a surface acoustic wave transducer structure according to claim 8, characterized in that: The step of forming an insulating dielectric layer on the interdigital layer comprises: forming an insulating material layer on the interdigital layer; forming a first patterned photoresist layer on the insulating material layer; Based on the first patterned photoresist layer, the insulating material layer is etched to form the first dielectric portion and the second dielectric portion arranged along the second direction, wherein the first dielectric portion also covers the first end of the second finger, and the second dielectric portion also covers the second end of the first finger; The step of forming an electrode layer on the insulating dielectric layer comprises: forming an electrode material layer on the insulating dielectric layer; forming a second patterned photoresist layer on the electrode material layer; Based on the second patterned photoresist layer, the electrode material layer is etched to form the first electrode and the second electrode, wherein the first electrode further exposes the side wall of the first dielectric portion facing the second dielectric portion, and the second electrode further exposes the side wall of the second dielectric portion facing the first dielectric portion.

10. The method for preparing a surface acoustic wave transducer structure according to claim 9, characterized in that: The electrode layer further includes a first bump and / or a second bump, the first bump is connected to the first electrode, the second bump is connected to the second electrode, and the first bump and / or the second bump are formed while etching the electrode material layer based on the second patterned photoresist layer to form the first electrode and the second electrode, the first bump protrudes relative to the first electrode to a side away from the second electrode, or the second bump protrudes relative to the second electrode to a side away from the first electrode; Alternatively, the electrode layer further includes holes, and the electrode material layer is etched based on the second patterned photoresist layer to form the first electrode and the second electrode, and holes are formed in the first electrode and the second electrode at the same time.

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