Surface acoustic wave resonator and manufacturing method thereof

Abstract

The invention provides a surface acoustic wave resonator and a manufacturing method thereof, and the method comprises the following steps: providing a piezoelectric substrate, and forming a first interdigital structure and a second interdigital structure on the upper surface of the piezoelectric substrate, the first interdigital structure and the second interdigital structure respectively comprise a first bus bar, a second bus bar, a plurality of first finger bar electrodes and a plurality of second finger bar electrodes, the first finger bar electrodes and the second finger bar electrodes are arranged on the first bus bar and the second bus bar at intervals in the Y direction and oppositely arranged in the X direction, and the first finger bar electrodes and the second finger bar electrodes are sequentially arranged at equal intervals in a staggered mode in the Y direction. The first and second bus bars are respectively arranged at intervals with the second and first ends; forming a low-sound-velocity filling groove which is adjacent to the first end and the second end and is opened from the upper surface of the piezoelectric substrate in the piezoelectric substrate; a filling layer for filling the low-sound-velocity filling groove is formed, and the X direction intersects with the Y direction. According to the manufacturing method of the surface acoustic wave resonator, the transverse wave mode is effectively inhibited, and the process is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of communication circuit components, and in particular to a surface acoustic wave resonator and a manufacturing method thereof. Background Art

[0002] Resonators have been widely used in today's 5G mobile communication era due to their advantages such as high frequency stability, low insertion loss and high selectivity.

[0003] However, the resonator devices currently used have serious transverse modes, that is, when the main mode of the surface acoustic wave resonator is excited, the interdigital transducer (IDT) will also generate a transverse acoustic wave mode propagating along the finger aperture direction. For example, the temperature compensated surface acoustic wave (TCSAW) resonator Figure 1-Figure 5 As shown in the figure, they are a top view cross-sectional schematic diagram of a surface acoustic wave resonator, Figure 1 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction, Figure 1 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction, Figure 1 Schematic diagram of the change of sound velocity of the surface acoustic wave resonator along the AA' direction and Figure 1 The admittance and real part of admittance of the surface acoustic wave resonator in the figure include piezoelectric substrate 01, first interdigital structure 02, first bus bar 021, first finger electrode 022, second interdigital structure 03, second bus bar 031, second finger electrode 032 and temperature compensation layer 04. The transverse acoustic wave mode will form a spurious response in the main mode bandgap region of the surface acoustic wave resonator device response, thereby causing a large insertion loss and in-band fluctuation and affecting the performance of the device.

[0004] At present, the commonly used technology for suppressing the lateral mode of the resonator is to increase the mass load at the end of the finger electrode. By adding a piston metal layer to this area, a velocity trap is formed in this area to suppress the leakage of sound waves and thus achieve the purpose of suppressing the lateral mode. However, this technology has extremely high requirements on the size and quality of the mass load, and thus puts forward higher requirements on the accuracy of the process. When the mass load is small, inaccurate alignment will lead to short circuit or even failure of the mass load process.

[0005] In view of this, there is an urgent need for a method for manufacturing a surface acoustic wave resonator that can effectively suppress the lateral mode of a surface acoustic wave filter and has a simple process. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a surface acoustic wave resonator and a method for manufacturing the same, so as to solve the problem that the surface acoustic wave resonator in the prior art has serious lateral modes and the process of suppressing the lateral modes is difficult.

[0007] To achieve the above object and other related objects, the present invention provides a method for manufacturing a surface acoustic wave resonator, comprising the following steps:

[0008] A piezoelectric substrate is provided, and a first interdigital structure and a second interdigital structure are formed on the upper surface of the piezoelectric substrate, wherein the first interdigital structure comprises a first bus bar and a plurality of first finger electrodes spaced along the Y direction on the first bus bar, and the second interdigital structure comprises a second bus bar and a plurality of second finger electrodes spaced along the Y direction on the second bus bar, the first bus bar and the second bus bar are disposed opposite to each other along the X direction, the first finger electrodes and the second finger electrodes are alternately and evenly spaced in sequence along the Y direction, an end of the second finger electrode away from the second bus bar is a second end, an end of the first finger electrode away from the first bus bar is a first end, the first bus bar is spaced from the second end, and the second bus bar is spaced from the first end;

[0009] forming low acoustic velocity filling grooves in the piezoelectric substrate, the low acoustic velocity filling grooves being adjacent to the first end and the second end, respectively, the low acoustic velocity filling grooves opening from the upper surface of the piezoelectric substrate and spaced apart from the bottom surface of the piezoelectric substrate;

[0010] A filling layer of a non-metallic material is formed to fill the low acoustic velocity filling groove, and the X direction intersects with the Y direction.

[0011] Optionally, the projection of the first end in the Z direction is embedded in the projection of the low-acoustic filling groove adjacent to the first end in the Z direction, and the side of the low-acoustic filling groove close to the first bus bar is spaced from the side wall of the first end away from the first bus bar by a first preset distance, and the side of the low-acoustic filling groove away from the first bus bar is spaced from the side wall of the first end away from the first bus bar by a second preset distance; the projection of the second end in the Z direction is embedded in the projection of the low-acoustic filling groove adjacent to the second end in the Z direction, and the side of the low-acoustic filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a first preset distance, and the side of the low-acoustic filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a second preset distance, and the Z direction is perpendicular to the plane formed by the X direction and the Y direction.

[0012] Optionally, the first bus bar is further provided with a plurality of first fake fingers which are arranged at intervals and correspond to the second finger electrodes in the X direction, and the projection of the first fake fingers in the Z direction is located between the first bus bar and the projection of the low acoustic velocity filling groove adjacent to the second end in the Z direction; the second bus bar is further provided with a plurality of second fake fingers which are arranged at intervals and correspond to the first finger electrodes in the X direction, and the projection of the second fake fingers in the Z direction is located between the second bus bar and the projection of the low acoustic velocity filling groove adjacent to the first end in the Z direction.

[0013] Optionally, a side of the low-acoustic velocity filling groove adjacent to the first end away from the first bus bar is flush with the side wall of the first end away from the first bus bar in the Y direction, and a side of the low-acoustic velocity filling groove close to the first bus bar is spaced a third preset distance from the side wall of the first end away from the first bus bar in the X direction; a side of the low-acoustic velocity filling groove adjacent to the second end away from the second bus bar is flush with the side wall of the second end away from the second bus bar in the Y direction, and a side of the low-acoustic velocity filling groove close to the second bus bar is spaced a third preset distance from the side wall of the second end away from the second bus bar in the X direction.

[0014] Optionally, a side of the low-acoustic velocity filling groove adjacent to the first end close to the first bus bar is flush with a side wall of the first end away from the first bus bar in the Y direction, and a side of the low-acoustic velocity filling groove away from the first bus bar is spaced apart from a side wall of the first end away from the first bus bar by a fourth preset distance in the X direction; a side of the low-acoustic velocity filling groove adjacent to the second end close to the second bus bar is flush with a side wall of the second end away from the second bus bar in the Y direction, and a side of the low-acoustic velocity filling groove away from the second bus bar is spaced apart from a side wall of the second end away from the second bus bar by a fourth preset distance in the X direction.

[0015] Optionally, the side of the low-acoustic velocity filling groove adjacent to the first end away from the first bus bar coincides with the projection of the edge of the second bus bar close to the first end in the Z direction, and the side of the low-acoustic velocity filling groove close to the first bus bar is spaced from the side wall of the first end away from the first bus bar by a fifth preset distance; the side of the low-acoustic velocity filling groove adjacent to the second end away from the second bus bar coincides with the projection of the edge of the first bus bar close to the second end in the Z direction, and the side of the low-acoustic velocity filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a fifth preset distance.

[0016] Optionally, the depth of the low acoustic velocity filling groove is less than λ, wherein λ is the wavelength of the surface acoustic wave.

[0017] Optionally, the material of the filling layer includes at least one of silicon dioxide, silicon nitride, glass, silicon oxynitride, and tantalum oxide.

[0018] Optionally, a temperature compensation layer is further provided in the surface acoustic wave resonator, and the temperature compensation layer at least covers the exposed surfaces of the first interdigital structure and the second interdigital structure.

[0019] Optionally, the material of the filling layer is the same as that of the temperature compensation layer.

[0020] Optionally, a passivation layer is further provided in the surface acoustic wave resonator, and the passivation layer covers the exposed surfaces of the first interdigital structure and the second interdigital structure.

[0021] The present invention also provides a surface acoustic wave resonator, which is manufactured by using any one of the above-mentioned methods for manufacturing a surface acoustic wave resonator.

[0022] As described above, the surface acoustic wave resonator and the manufacturing method thereof of the present invention have the following beneficial effects: by forming the low acoustic velocity filling grooves adjacent to the first end and the second end in the piezoelectric substrate respectively and opening from the upper surface of the piezoelectric substrate and with the bottom spaced apart from the bottom surface of the piezoelectric substrate, and forming the filling layer filling the low acoustic velocity filling grooves in the low acoustic velocity filling grooves, not only the acoustic wave energy is better confined within the aperture range, but also the transverse wave mode in the bandgap region of the device is effectively suppressed. Moreover, the low acoustic velocity filling grooves are formed in the piezoelectric substrate and the filling layer fills the low acoustic velocity filling grooves. The structure of the surface acoustic wave resonator can be optimized according to its application requirements, and the low acoustic velocity filling grooves with different sizes and shapes can be selected or the first dummy fingers and the second dummy fingers can be set in the first interdigitated structure and the second interdigitated structure, thereby improving the adaptability and flexibility of the design of the surface acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure shows a top cross-sectional schematic diagram of a surface acoustic wave resonator in the prior art.

[0024] Figure 2 Display as Figure 1 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0025] Figure 3 Display as Figure 1 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0026] Figure 4 Display as Figure 1Schematic diagram of the sound velocity change of the cross-sectional schematic diagram of the surface acoustic wave resonator along the AA' direction.

[0027] Figure 5 Display as Figure 1 Graph of the admittance and real part of the admittance of a surface acoustic wave resonator.

[0028] Figure 6 It is a schematic diagram showing the manufacturing process of the surface acoustic wave resonator of the present invention.

[0029] Figure 7 A schematic cross-sectional view of a piezoelectric substrate showing a method for manufacturing a surface acoustic wave resonator of the present invention.

[0030] Figure 8 It is a cross-sectional schematic diagram showing the method for manufacturing a surface acoustic wave resonator of the present invention after forming a first interdigital structure and a second interdigital structure.

[0031] Fig. 9 It is a schematic cross-sectional view showing the method for manufacturing a surface acoustic wave resonator of the present invention after forming a low acoustic velocity filling groove.

[0032] Fig.10 A schematic top cross-sectional view of a surface acoustic wave resonator is shown, showing a method for manufacturing a surface acoustic wave resonator of the present invention.

[0033] Fig.11 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.10 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0034] Fig.12 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.10 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0035] Fig.13 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.10 Schematic diagram of the change in sound velocity in the cross section along the AA' direction in the surface acoustic wave resonator.

[0036] Fig.14 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.10 Graph of the admittance and real part of the admittance of a surface acoustic wave resonator.

[0037] Fig.15 Another schematic top cross-sectional view of a surface acoustic wave resonator is shown in the method for manufacturing the surface acoustic wave resonator of the present invention.

[0038] Fig.16 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.15Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0039] Fig.17 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.15 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0040] Fig.18 A third schematic top cross-sectional view of a surface acoustic wave resonator is shown in the method for manufacturing the surface acoustic wave resonator of the present invention.

[0041] Fig.19 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.18 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0042] Fig. 20 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.18 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0043] Fig.21 A fourth schematic top cross-sectional view of a surface acoustic wave resonator is shown in the method for manufacturing the surface acoustic wave resonator of the present invention.

[0044] Fig. 22 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.21 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0045] Fig.23 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.21 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0046] Fig.24 A fifth schematic top cross-sectional view of a surface acoustic wave resonator is shown in the method for manufacturing the surface acoustic wave resonator of the present invention.

[0047] Fig.25 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.24 Schematic diagram of the cross section of the surface acoustic wave resonator along the AA' direction.

[0048] Fig.26 The method for manufacturing the surface acoustic wave resonator of the present invention is shown as follows Fig.24 Schematic diagram of the cross section of the surface acoustic wave resonator along the BB' direction.

[0049] Component number description

[0050] 01 Piezoelectric Substrate

[0051] 02 First interdigital structure

[0052] 021 First Bus

[0053] 022 First finger electrode

[0054] 03 Second interdigital structure

[0055] 031 Second bus bar

[0056] 032 Second finger electrode

[0057] 04 Temperature compensation layer

[0058] 1 Piezoelectric substrate

[0059] 2 First interdigital structure

[0060] 21 First Bus

[0061] 22 First finger electrode

[0062] 3 Second interdigital structure

[0063] 31 Second bus bar

[0064] 32 Second finger electrode

[0065] 4 Low-sonic filling tank

[0066] 5 Filling layer

[0067] 6 Temperature compensation layer

[0068] 7 First false finger

[0069] 8 Second false finger DETAILED DESCRIPTION

[0070] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0071] See also Figures 6 to 26. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0072] Embodiment 1

[0073] This embodiment provides a method for manufacturing a surface acoustic wave resonator. Figure 6 As shown, it is a schematic diagram of the manufacturing process of the surface acoustic wave resonator, which includes the following steps:

[0074] S1: providing a piezoelectric substrate, forming a first interdigital structure and a second interdigital structure on the upper surface of the piezoelectric substrate, wherein the first interdigital structure comprises a first bus bar and a plurality of first finger electrodes spaced along the Y direction on the first bus bar, and the second interdigital structure comprises a second bus bar and a plurality of second finger electrodes spaced along the Y direction on the second bus bar, the first bus bar and the second bus bar are disposed opposite to each other along the X direction, the first finger electrodes and the second finger electrodes are alternately and evenly spaced in sequence along the Y direction, the end of the second finger electrode away from the second bus bar is the second end, the end of the first finger electrode away from the first bus bar is the first end, the first bus bar is spaced from the second end, and the second bus bar is spaced from the first end;

[0075] S2: forming low acoustic velocity filling grooves adjacent to the first end and the second end respectively in the piezoelectric substrate, wherein the low acoustic velocity filling grooves open from the upper surface of the piezoelectric substrate and are spaced apart from the bottom surface of the piezoelectric substrate;

[0076] S3: A filling layer of a non-metallic material filling the low-sonic velocity filling groove is formed, and the X direction intersects with the Y direction.

[0077] For details, please refer to Figure 7-Figure 8, perform step S1, provide a piezoelectric substrate 1, form a first interdigitated structure 2 and a second interdigitated structure 3 on the upper surface of the piezoelectric substrate 1, the first interdigitated structure 2 includes a first bus bar 21 and a plurality of first finger electrodes 22 spaced along the Y direction on the first bus bar 21, the second interdigitated structure 3 includes a second bus bar 31 and a plurality of second finger electrodes 32 spaced along the Y direction on the second bus bar 31, the first bus bar 21 and the second bus bar 31 are arranged opposite to each other along the X direction, the first finger electrodes 22 and the second finger electrodes 32 are arranged alternately and evenly along the Y direction, the end of the second finger electrode 32 away from the second bus bar 31 is the second end 33, the end of the first finger electrode 22 away from the first bus bar 21 is the first end 23, the first bus bar 21 and the second end 33 are spaced, and the second bus bar 31 and the first end 23 are spaced.

[0078] Specifically, Figure 7 , which is a cross-sectional schematic diagram of a piezoelectric substrate 1. The material of the piezoelectric substrate 1 includes at least one of lithium tantalate, lithium niobate, quartz, lanthanum gallium silicate, or other suitable piezoelectric materials. In this embodiment, the material of the piezoelectric substrate 1 is 128°YX lithium niobate.

[0079] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the shape and size of the piezoelectric substrate 1 can be selected according to actual conditions, and are not limited here.

[0080] Specifically, the piezoelectric substrate 1 is used to provide a stable surface acoustic wave propagation medium for the surface acoustic wave resonator.

[0081] Specifically, Figure 8 As shown, it is a cross-sectional schematic diagram after forming the first interdigitated structure 2 and the second interdigitated structure 3. The formation of the first interdigitated structure 2 and the second interdigitated structure 3 includes the following steps: forming an interdigitated electrode material layer (not shown) above the piezoelectric substrate 1, forming a patterned shielding layer (not shown) above the interdigitated electrode material layer, and etching the interdigitated electrode material layer based on the patterned shielding layer to obtain the first interdigitated structure 2 and the second interdigitated structure 3.

[0082] Specifically, forming a patterned shielding layer is a conventional technical method and is not limited here.

[0083] Specifically, the method of forming the interdigital electrode material layer includes sputtering, electroplating or other suitable methods.

[0084] Specifically, the material of the first interdigitated structure 2 includes at least one of nickel, molybdenum, iron, copper, tungsten, gold, silver, aluminum, and platinum, or other suitable electrode materials; the material of the second interdigitated structure 3 includes at least one of nickel, molybdenum, iron, copper, tungsten, gold, silver, aluminum, and platinum, or other suitable electrode materials.

[0085] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the size of the first bus bar 21 can be selected according to the actual situation, and there is no restriction here; the size of the first finger electrode 22 can be selected according to the actual situation, and there is no restriction here; the size of the second bus bar 31 can be selected according to the actual situation, and there is no restriction here; the size of the second finger electrode 32 can be selected according to the actual situation, and there is no restriction here. It should be noted that the length of the first finger electrode 22 in the Y direction should be greater than half of the distance between the first bus bar 21 and the second bus bar 31, and the length of the second finger electrode 32 in the Y direction should be greater than half of the distance between the first bus bar 21 and the second bus bar 31.

[0086] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the spacing between the first finger electrode 22 and the second finger electrode 32 can be selected according to actual conditions, and is not limited here.

[0087] Specifically, the lengths of the plurality of first finger electrodes 22 in the Y direction may be the same or different, and may be selected according to actual conditions; the lengths of the plurality of second finger electrodes 32 in the Y direction may be the same or different, and may be selected according to actual conditions. In this embodiment, the lengths of the plurality of first finger electrodes 22 in the Y direction are the same; the lengths of the plurality of second finger electrodes 32 in the Y direction are the same.

[0088] Specifically, the first finger electrodes 22 and the second finger electrodes 32 are interlaced and periodically distributed, and surface acoustic waves are excited on the surface of the piezoelectric substrate 1 through the inverse piezoelectric effect, and the first interdigital structure 2 and the second interdigital structure 3 realize the conversion of electrical signals and acoustic signals.

[0089] For details, please refer to Figure 9-14 , execute steps S2-S3, form a low acoustic velocity filling groove 4 adjacent to the first end 23 and the second end 33 respectively in the piezoelectric substrate 1, the low acoustic velocity filling groove 4 is opened from the upper surface of the piezoelectric substrate 1 and is spaced from the bottom surface of the piezoelectric substrate 1; and form a filling layer 5 of a non-metallic material filling the low acoustic velocity filling groove 4.

[0090] Specifically, Fig. 9 , which is a schematic cross-sectional view after forming the low acoustic velocity filling groove 4, the method for forming the low acoustic velocity filling groove 4 includes plasma etching, wet etching or other suitable etching methods. In this embodiment, the method for forming the low acoustic velocity filling groove 4 is plasma etching.

[0091] Specifically, the shape of the low-sonic-velocity filling slot 4 includes a rectangle, a strip, a hole, a circle, a semicircle, a trapezoid, a triangle, a special shape or other suitable shapes.

[0092] Specifically, the method of forming the filling layer 5 includes electron beam evaporation, physical vapor deposition, chemical vapor deposition or other suitable methods.

[0093] Specifically, the material of the filling layer 5 includes at least one of silicon dioxide, silicon nitride, glass, silicon oxynitride, tantalum oxide, or other suitable hard non-metallic materials. In this embodiment, the material of the filling layer 5 is silicon dioxide.

[0094] As an example, a temperature compensation layer 6 is further provided in the surface acoustic wave resonator, and the temperature compensation layer 6 at least covers the exposed surfaces of the first interdigital structure 2 and the second interdigital structure 3 .

[0095] Specifically, the temperature compensation layer 6 also covers the exposed surface of the piezoelectric substrate 1 .

[0096] Specifically, Figure 10-12 As shown in the figure, they are a top view cross-sectional schematic diagram of a surface acoustic wave resonator, Fig.10 A schematic cross-sectional view of the surface acoustic wave resonator along the AA' direction and Fig.10 The schematic cross-sectional view of the surface acoustic wave resonator along the BB' direction is shown in FIG. 1 . The method for forming the temperature compensation layer 6 includes electron beam evaporation, physical vapor deposition, chemical vapor deposition or other suitable methods.

[0097] Specifically, the material of the temperature compensation layer 6 includes silicon dioxide, fluorine-containing silicon oxide, silicon nitride or other suitable silicon-containing dielectric films with a positive temperature coefficient. In this embodiment, the material of the temperature compensation layer 6 is silicon dioxide.

[0098] Specifically, after the temperature compensation layer 6 is formed, the method further includes removing the redundant temperature compensation layer 6 located above the first interdigital structure 2 and the second interdigital structure 3 .

[0099] Specifically, the method of removing the redundant temperature compensation layer 6 includes chemical mechanical polishing or other suitable methods.

[0100] Specifically, during the preparation of the temperature compensation layer 6, the temperature compensation layer 6 is controlled by a chemical mechanical polishing process, thereby achieving the preparation of a temperature compensation layer 6 with stable thickness, good surface uniformity and low surface roughness, thereby improving the performance and qualified rate of the resonator.

[0101] Specifically, when a temperature compensation layer 6 is formed on the exposed surfaces of the second interdigitated structure 2 and the third interdigitated structure 3, the temperature stability of the resonator is significantly improved, and the temperature compensation layer 6 is usually made of materials with a positive temperature coefficient such as silicon dioxide, which offsets the influence of the temperature change of the substrate material on the frequency, and the piezoelectric substrate 1 can be directly used as a substrate for making the first interdigitated structure 2 and the second interdigitated structure 3. In addition, the type of the surface acoustic wave resonator at this time is a temperature compensated surface acoustic wave resonator, and the second interdigitated structure 2 and the third interdigitated structure 3 are usually made of copper.

[0102] As an example, the material of the filling layer 5 is the same as the material of the temperature compensation layer 6 .

[0103] Specifically, by setting the material of the filling layer 5 to be consistent with the material of the temperature compensation layer 6 , the filling layer 5 and the temperature compensation layer 6 can be formed in an integrated manner, thereby further simplifying the process.

[0104] As an example, a passivation layer (not shown) is further provided in the surface acoustic wave resonator, and the passivation layer covers the exposed surfaces of the first interdigital structure 2 and the second interdigital structure 3 .

[0105] Specifically, when a passivation layer is provided in the surface acoustic wave resonator, that is, the piezoelectric substrate 1 can be a piezoelectric layer on the upper surface of a piezoelectric single crystal film on insulator (POI) substrate, that is, a high-resistance substrate (not shown) and an insulating layer (not shown) stacked in sequence are also provided under the piezoelectric substrate 1, and the piezoelectric substrate 1 is located on the insulating layer. At this time, the type of the surface acoustic wave resonator is a POI type surface acoustic wave resonator, and the second interdigitated structure 2 and the third interdigitated structure 3 usually adopt multi-layer electrode materials such as titanium-copper-aluminum, copper-aluminum, and titanium-aluminum.

[0106] Specifically, by setting the second interdigital structure 2 and the third interdigital structure 3 to be a multilayer electrode material such as titanium-copper-aluminum, copper-aluminum, titanium-aluminum, etc., the power tolerance can be improved.

[0107] Specifically, the material of the high-resistance substrate includes silicon or other suitable materials; the material of the insulating layer includes silicon dioxide or other suitable insulating materials.

[0108] As an example, the projection of the first end 23 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the first end 23 in the Z direction, and the side of the low-acoustic filling groove 4 close to the first bus bar 21 is spaced from the side wall of the first end 23 away from the first bus bar 21 by a first preset distance, and the side of the low-acoustic filling groove 4 away from the first bus bar 21 is spaced from the side wall of the first end 23 away from the first bus bar 21 by a second preset distance; the projection of the second end 33 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the second end 33 in the Z direction, and the side of the low-acoustic filling groove 4 close to the second bus bar 31 is spaced from the side wall of the second end 33 away from the second bus bar 31 by a first preset distance, and the side of the low-acoustic filling groove 4 away from the second bus bar 31 is spaced from the side wall of the second end 33 away from the second bus bar 31 by a second preset distance, and the Z direction is perpendicular to the plane formed by the X direction and the Y direction. The projection of the first end 23 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the first end 23 in the Z direction, which means that the projection boundary of the first end 23 in the Z direction coincides with the internal projection boundary of the low-acoustic filling groove 4 adjacent to the first end 23 in the Z direction, but the projections do not intersect; the projection of the second end 33 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the second end 33 in the Z direction, which means that the projection boundary of the second end 33 in the Z direction coincides with the internal projection boundary of the low-acoustic filling groove 4 adjacent to the second end 33 in the Z direction, but the projections do not intersect.

[0109] Specifically, the first preset distance is equal to the second preset distance. In this embodiment, the first preset distance and the second preset distance are both 0.35 μm.

[0110] Specifically, the depth h of the low acoustic velocity filling groove 4 is less than λ, where λ is the wavelength of the surface acoustic wave. The depth h here refers to the distance from the opening to the bottom of the low acoustic velocity filling groove 4. In this embodiment, the depth h of the low acoustic velocity filling groove 4 is 0.6λ.

[0111] Specifically, Fig.13 and Fig.14 As shown, they are Fig.10 Schematic diagram of the change of the sound velocity of the cross section along the AA' direction in the surface acoustic wave resonator and Fig.10 The admittance and real part of the surface acoustic wave resonator of the embodiment are shown in Fig. 1. Compared with the two surface acoustic wave resonators in the background technology, the surface acoustic wave resonator of the embodiment significantly suppresses the transverse wave mode in the device bandgap region, and the admittance and conductance characteristics in the frequency range near the anti-resonance point are also improved accordingly. Therefore, forming the low-acoustic-velocity filling groove 4 adjacent to the first end 23 and the second end 33 respectively and forming the filling layer 5 in the low-acoustic-velocity filling groove 4 can significantly suppress the transverse wave mode in the device bandgap region.

[0112] Specifically, by forming a low-acoustic filling groove 4 adjacent to the first end 23 and the second end 33 respectively, and the projection of the first end 23 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the first end 23 in the Z direction, and the side of the low-acoustic filling groove 4 close to the first bus bar 21 is spaced a first preset distance from the side wall of the first end 23 away from the first bus bar 21, and the side away from the first bus bar 21 is spaced a second preset distance from the side wall of the first end 23 away from the first bus bar 21; the projection of the second end 33 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the second end 33 in the Z direction, and the side of the low-acoustic filling groove 4 close to the second bus bar 31 is spaced a second preset distance from the side wall of the first end 23 away from the first bus bar 21 3 is spaced apart from the side wall of the second bus bar 31 by a first preset distance, and the side away from the second bus bar 31 and the second end 33 are spaced apart from the side wall of the second bus bar 31 by a second preset distance, that is, by forming a low-acoustic-velocity filling groove 4 adjacent to the first end 23 and the second end 33 respectively in the piezoelectric substrate 1, the low-acoustic-velocity filling groove 4 is opened from the upper surface of the piezoelectric substrate 1 and is spaced apart from the bottom surface of the piezoelectric substrate 1, and a filling layer 5 filling the low-acoustic-velocity filling groove 4 is formed, which not only better confines the acoustic wave energy within the aperture range, but also effectively suppresses the transverse wave mode in the bandgap region of the device, and compared with the method of forming the piston metal layer, the method of forming the low-acoustic-velocity filling groove 4 and the filling layer 5 is simple, has low process requirements, and is low in cost.

[0113] The manufacturing method of the surface acoustic wave resonator of this embodiment is by forming a low-acoustic filling groove 4 adjacent to the first end 23 and the second end 33 respectively, and the projection of the first end 23 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the first end 23 in the Z direction, and the side of the low-acoustic filling groove 4 close to the first bus bar 21 is spaced a first preset distance from the side wall of the first end 23 away from the first bus bar 21, and the side away from the first bus bar 21 is spaced a second preset distance from the side wall of the first end 23 away from the first bus bar 21; the projection of the second end 33 in the Z direction is embedded in the projection of the low-acoustic filling groove 4 adjacent to the second end 33 in the Z direction, and the side of the low-acoustic filling groove 4 close to the second bus bar 31 is spaced a first preset distance from the side wall of the second end 33 away from the second bus bar 31, and away from the second One side of the bus bar 31 is spaced a second preset distance from the second end 33 and the side wall of the second bus bar 31, that is, by forming a low-acoustic filling groove 4 adjacent to the first end 23 and the second end 33 respectively in the piezoelectric substrate 1, the low-acoustic filling groove 4 opens from the upper surface of the piezoelectric substrate 1 and is spaced from the bottom surface of the piezoelectric substrate 1, and a filling layer 5 is formed to fill the low-acoustic filling groove 4, which not only better constrains the acoustic wave energy within the aperture range, but also effectively suppresses the transverse wave mode in the bandgap region of the device, and the low-acoustic filling groove 4 is formed in the piezoelectric substrate 1, the filling layer 5 fills the low-acoustic filling groove 4, and in the temperature-compensated surface acoustic wave resonator, the temperature compensation layer 6 and the filling layer 5 can be formed in an integrated manner, that is, compared with the method of forming a piston metal layer, the method of forming the low-acoustic filling groove 4 and the filling layer 5 is simple, has low process requirements, and is low in cost.

[0114] Embodiment 2

[0115] This embodiment provides another method for manufacturing a surface acoustic wave resonator. Figure 19-21 As shown, they are another schematic diagram of a top view cross section of a surface acoustic wave resonator, Fig.19 A schematic cross-sectional view of the surface acoustic wave resonator along the AA' direction and Fig.19 A schematic cross-sectional view of a surface acoustic wave resonator along the BB' direction is provided. The difference between the method for manufacturing the surface acoustic wave resonator of this embodiment and the method for manufacturing the surface acoustic wave resonator described in Example 1 is that a plurality of first dummy fingers 7 which are arranged at intervals and correspond to the second finger electrode 32 in the X direction are further provided on the first bus bar 21, and the projection of the first dummy fingers 7 in the Z direction is located between the first bus bar 21 and the projection of the low acoustic velocity filling groove 4 adjacent to the second end 33 in the Z direction; a plurality of second dummy fingers 8 which are arranged at intervals and correspond to the first finger electrode 22 in the X direction are further provided on the second bus bar 31, and the projection of the second dummy fingers 8 in the Z direction is located between the second bus bar 31 and the projection of the low acoustic velocity filling groove 4 adjacent to the first end 23 in the Z direction.

[0116] Specifically, the length of the first dummy finger 7 in the X direction is smaller than the distance between the first bus bar 21 and the second bus bar 31 ; the length of the second dummy finger 8 in the X direction is smaller than the distance between the second bus bar 21 and the second bus bar 31 .

[0117] The manufacturing method of the surface acoustic wave resonator of this embodiment is to set a first dummy finger 7 between the low acoustic velocity filling groove 4 adjacent to the second end 33 and the first bus bar 21, and set a second dummy finger 8 between the low acoustic velocity filling groove 4 adjacent to the first end 23 and the second bus bar 31, thereby enhancing the electric field distribution at the first end 23 and the second end 33, making the electric field more concentrated, thereby improving the sensitivity of the filter, better confining the sound wave energy within the aperture range, and effectively suppressing the transverse wave mode in the bandgap region of the device.

[0118] Embodiment 3

[0119] This embodiment provides a third method for manufacturing a surface acoustic wave resonator. Figure 22-Figure 24 As shown, they are another schematic diagram of a top view cross section of a surface acoustic wave resonator, Fig. 22 A schematic cross-sectional view of the surface acoustic wave resonator along the AA' direction and Fig. 22 The schematic cross-sectional view of the surface acoustic wave resonator along the BB' direction of the present embodiment is different from the surface acoustic wave resonator manufacturing method described in the first embodiment in that the side of the low acoustic velocity filling groove 4 adjacent to the first end 23 away from the first bus bar 21 is flush with the side wall of the first end 23 away from the first bus bar 21 in the Y direction, and the side of the low acoustic velocity filling groove 4 close to the first bus bar 21 is spaced apart from the side wall of the first end 23 away from the first bus bar 21 by a third preset distance in the X direction; the side of the low acoustic velocity filling groove 4 adjacent to the second end 33 away from the second bus bar 31 is flush with the side wall of the second end 33 away from the second bus bar 31 in the Y direction, and the side of the low acoustic velocity filling groove 4 close to the second bus bar 31 is spaced apart from the side wall of the second end 33 away from the second bus bar 31 by a third preset distance in the X direction.

[0120] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the third preset distance can be selected according to actual conditions, and is not limited here.

[0121] Specifically, by setting the side of the low-acoustic filling groove 4 adjacent to the first end 23 away from the first bus bar 21 to be flush with the side wall of the first end 23 away from the first bus bar 21 in the Y direction, and the side close to the first bus bar 21 to be separated from the side wall of the first end 23 away from the first bus bar 21 by a third preset distance in the X direction; the side of the low-acoustic filling groove 4 adjacent to the second end 33 away from the second bus bar 31 is flush with the side wall of the second end 33 away from the second bus bar 31 in the Y direction, and the side close to the second bus bar 31 is separated from the side wall of the second end 33 away from the second bus bar 31 by a third preset distance in the X direction, while effectively suppressing the shear wave mode in the bandgap region of the device, the process of forming the low-acoustic filling groove is further simplified and the process requirements are reduced.

[0122] Embodiment 4

[0123] This embodiment provides a fourth method for manufacturing a surface acoustic wave resonator. Figure 21-23 As shown, they are another schematic diagram of a top view cross section of a surface acoustic wave resonator, Fig.21 A schematic cross-sectional view of the surface acoustic wave resonator along the AA' direction and Fig.21 0014] A schematic cross-sectional view of a surface acoustic wave resonator along the BB' direction is provided. The method for manufacturing the surface acoustic wave resonator of the present embodiment differs from the method for manufacturing the surface acoustic wave resonator described in the first embodiment in that a side of the low acoustic velocity filling groove 4 adjacent to the first end 23 close to the first bus bar 21 is flush with a side wall of the first end 23 away from the first bus bar 21 in the Y direction, and a side of the low acoustic velocity filling groove 4 away from the first bus bar 21 is spaced apart from a side wall of the first end 23 away from the first bus bar 21 by a fourth preset distance in the X direction; a side of the low acoustic velocity filling groove 4 adjacent to the second end 33 close to the second bus bar 31 is flush with a side wall of the second end 33 away from the second bus bar 31 in the Y direction, and a side of the low acoustic velocity filling groove 4 away from the second bus bar 31 is spaced apart from a side wall of the second end 33 away from the second bus bar 31 by a fourth preset distance in the X direction.

[0124] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the fourth preset distance can be selected according to actual conditions, and is not limited here.

[0125] Specifically, by setting the side of the low-acoustic-speed filling groove 4 adjacent to the first end 23 close to the first bus bar 21 to be flush with the side wall of the first end 23 away from the first bus bar 21 in the Y direction, and the side away from the first bus bar 21 to be separated from the side wall of the first end 23 away from the first bus bar 21 by a fourth preset distance in the X direction; the side of the low-acoustic-speed filling groove 4 adjacent to the second end 33 close to the second bus bar 31 to be flush with the side wall of the second end 33 away from the second bus bar 31 in the Y direction, and the side away from the second bus bar 31 to be separated from the side wall of the second end 33 away from the second bus bar 31 by a fourth preset distance in the X direction, while effectively suppressing the transverse wave mode in the bandgap region of the device, the process of forming the low-acoustic-speed filling groove is further simplified and the process requirements are reduced.

[0126] Embodiment 5

[0127] This embodiment provides a fifth method for manufacturing a surface acoustic wave resonator. Figure 24-26 As shown, they are another schematic diagram of a top view cross section of a surface acoustic wave resonator, Fig.24 A schematic cross-sectional view of the surface acoustic wave resonator along the AA' direction and Fig.24 The schematic cross-sectional view of the surface acoustic wave resonator along the BB' direction of the present embodiment is different from the method for manufacturing the surface acoustic wave resonator described in the first embodiment in that the side of the low acoustic velocity filling groove 4 adjacent to the first end 23 away from the first bus bar 21 coincides with the projection of the edge of the second bus bar 31 close to the first end 23 in the Z direction, and the side of the low acoustic velocity filling groove 4 close to the first bus bar 21 is spaced from the side wall of the first end 23 away from the first bus bar 21 by a fifth preset distance; the side of the low acoustic velocity filling groove 4 adjacent to the second end 33 away from the second bus bar 31 coincides with the projection of the edge of the first bus bar 21 close to the second end 33 in the Z direction, and the side of the low acoustic velocity filling groove 4 close to the second bus bar 31 is spaced from the side wall of the second end 33 away from the second bus bar 31 by a fifth preset distance.

[0128] Specifically, under the condition that the performance of the surface acoustic wave resonator is met, the fifth preset distance can be selected according to actual conditions, and is not limited here.

[0129] Specifically, by setting the side of the low-acoustic-velocity filling groove 4 adjacent to the first end 23 away from the first bus bar 21 to coincide with the projection of the edge of the second bus bar 31 close to the first end 23 in the Z direction, and the side close to the first bus bar 21 is spaced from the side wall of the first end 23 away from the first bus bar 21 by a fifth preset distance; the side of the low-acoustic-velocity filling groove 4 adjacent to the second end 33 away from the second bus bar 31 is spaced from the side wall of the second end 33 away from the second bus bar 31 by a fifth preset distance, thereby further suppressing the transverse wave mode in the bandgap region of the device and improving the device performance.

[0130] Embodiment 6

[0131] The present embodiment provides a surface acoustic wave resonator, which is manufactured by the surface acoustic wave resonator described in any one of the first to fifth embodiments. The surface acoustic wave resonator includes a piezoelectric substrate 1, a first interdigitated structure 2, a second interdigitated structure 3, a low acoustic velocity filling groove 4, a filling layer 5 and a temperature compensation layer 6, wherein the first interdigitated structure 2 and the second interdigitated structure 3 are located on the upper surface of the piezoelectric substrate 1, the first interdigitated structure 2 includes a first bus bar 21 and a plurality of first finger electrodes 22 arranged on the first bus bar 21 at intervals along the Y direction, the second interdigitated structure 3 includes a second bus bar 31 and a plurality of second finger electrodes 32 arranged on the second bus bar 31 at intervals along the Y direction, the first bus bar The first finger electrode 21 and the second bus bar 31 are arranged opposite to each other along the X direction, the first finger electrode 22 and the second finger electrode 32 are arranged in sequence along the Y direction in an alternating and equal interval manner, the end of the second finger electrode 32 away from the second bus bar 31 is the second end 33, the end of the first finger electrode 22 away from the first bus bar 21 is the first end 23, and the first bus bar 21 and the second end 33 are arranged at intervals, and the second bus bar 31 and the first end 23 are arranged at intervals; the low acoustic velocity filling groove 4 is located in the piezoelectric substrate 1 and is adjacent to the first end 23 and the second end 33 respectively, the low acoustic velocity filling groove 4 is opened from the upper surface of the piezoelectric substrate 1 and is arranged at intervals with the bottom surface of the piezoelectric substrate 1; the filling layer 5 is made of non-metallic material and fills the low acoustic velocity filling groove 4, and the X direction intersects with the Y direction.

[0132] Specifically, the specific structure of the surface acoustic wave resonator can be selected according to actual conditions. For example, in Example 1, the low-acoustic filling groove 4 adjacent to the first end 23 surrounds the projection of the first end 23 in the Z direction, and the side of the low-acoustic filling groove 4 close to the first bus bar 21 is spaced a first preset distance from the side wall of the first end 23 away from the first bus bar 21, and the side away from the first bus bar 21 is spaced a second preset distance from the side wall of the first end 23 away from the first bus bar 21; the low-acoustic filling groove 4 adjacent to the second end 23 surrounds the projection of the second end 33 in the Z direction, and the side of the low-acoustic filling groove 4 close to the second bus bar 31 is spaced a first preset distance from the side wall of the second end 33 away from the second bus bar 31, and the side away from the second bus bar 31 is spaced a second preset distance from the second end 33 is spaced a second preset distance away from the side wall of the second bus bar 31, and the first preset distance is equal to the second preset distance; as in the second embodiment, the first bus bar 21 is further provided with a plurality of first fake fingers 7 which are arranged at intervals and correspond to the second finger electrode 32 in the X direction, and the projection of the first fake finger 7 in the Z direction is located between the first bus bar 21 and the projection of the low acoustic velocity filling groove 4 adjacent to the second end 33 in the Z direction; the second bus bar 31 is further provided with a plurality of second fake fingers 8 which are arranged at intervals and correspond to the first finger electrode 22 in the X direction, and the projection of the second fake finger 8 in the Z direction is located between the second bus bar 31 and the projection of the low acoustic velocity filling groove 4 adjacent to the first end 23 in the Z direction; as in the third embodiment, the projection of the low acoustic velocity filling groove 4 adjacent to the first end 23 The side of the low-acoustic filling groove 4 adjacent to the second end 33 away from the second bus bar 31 is flush with the side wall of the first end 23 away from the first bus bar 21 in the Y direction, and the side close to the first bus bar 21 is spaced apart from the side wall of the first end 23 away from the first bus bar 21 by a third preset distance in the X direction; the side of the low-acoustic filling groove 4 adjacent to the second end 33 away from the second bus bar 31 is flush with the side wall of the second end 33 away from the second bus bar 31 in the Y direction, and the side close to the first bus bar 21 is spaced apart from the side wall of the second end 33 away from the second bus bar 31 by a third preset distance in the X direction; as in the fourth embodiment, the side of the low-acoustic filling groove 4 adjacent to the first end 23 close to the first bus bar 21 is flush with the side wall of the first end 23 away from the first bus bar 21 in the Y direction The side of the low-acoustic-velocity filling groove 4 adjacent to the second end 33, which is close to the second bus bar 31, is flush with the side wall of the second end 33 away from the second bus bar 31 in the Y direction, and the side away from the first bus bar 21 is spaced apart from the side wall of the second end 33 away from the second bus bar 31 by a fourth preset distance in the X direction; as in the fifth embodiment, the side of the low-acoustic-velocity filling groove 4 adjacent to the first end 23, which is away from the first bus bar 21, coincides with the projection of the edge of the second bus bar 31 close to the first end 23 in the Z direction, and the side close to the first bus bar 21 is spaced apart from the side wall of the first end 23 away from the first bus bar 21 by a fifth preset distance;The side of the low-sound-velocity filling slot 4 adjacent to the second end 33 away from the second bus bar 31 coincides with the projection of the edge of the first bus bar 21 close to the second end 33 in the Z direction, and the side close to the second bus bar 31 is spaced from the side wall of the second end 33 away from the second bus bar 31 by a fifth preset distance. ;

[0133] Specifically, a temperature compensation layer 6 is further provided in the surface acoustic wave resonator, and the temperature compensation layer 6 at least covers the first interdigital structure 2 , the second interdigital structure 3 and the exposed surface of the piezoelectric substrate 1 .

[0134] Specifically, the temperature compensation layer 6 also covers the exposed surface of the piezoelectric substrate.

[0135] Specifically, by forming a temperature compensation layer 6 on the exposed surfaces of the second interdigital structure 2 and the third interdigital structure 3 of the piezoelectric substrate 1, the piezoelectric substrate 1 can be directly used as a substrate for making the first interdigital structure 2 and the second interdigital structure 3. At this time, the surface acoustic wave resonator is a temperature compensated surface acoustic wave resonator.

[0136] As an example, a passivation layer (not shown) is further provided in the surface acoustic wave resonator, and the passivation layer covers the exposed surfaces of the first interdigital structure 2 and the second interdigital structure 3 .

[0137] Specifically, when a passivation layer is provided in the surface acoustic wave resonator, that is, the piezoelectric substrate 1 can be a piezoelectric layer on the upper surface of a POI substrate on an insulator, that is, a high-resistance substrate (not shown) and an insulating layer (not shown) stacked in sequence are also provided below the piezoelectric substrate 1, and the piezoelectric substrate 1 is located on the insulating layer. At this time, the type of the surface acoustic wave resonator is a POI type surface acoustic wave resonator.

[0138] The surface acoustic wave resonator of this embodiment can optimize its structure according to its application requirements, select low-acoustic filling grooves 4 of different sizes and shapes, or set first dummy fingers 7 and second dummy fingers 8 on the first interdigitated structure 2 and the second interdigitated structure 3, thereby improving the adaptability and flexibility of the design and effectively suppressing the transverse wave mode in the bandgap region of the device.

[0139] In summary, the surface acoustic wave resonator and its manufacturing method of the present invention, by forming low acoustic velocity filling grooves adjacent to the first end and the second end in the piezoelectric substrate respectively, and forming a filling layer filling the low acoustic velocity filling groove in the low acoustic velocity filling groove, not only better constrains the acoustic wave energy within the aperture range, effectively suppresses the transverse wave mode in the device bandgap region, and the low acoustic velocity filling groove is formed in the piezoelectric substrate, the filling layer fills the low acoustic velocity filling groove, and in the temperature compensation type surface acoustic wave resonator, the temperature compensation layer and the filling layer can be formed in an integrated manner, that is, compared with the method of forming the piston metal layer, the method of forming the low acoustic velocity filling groove and the filling layer is simple, has low process requirements, and is also low in cost, and the structure of the surface acoustic wave resonator can be optimized according to its application requirements, and low acoustic velocity filling grooves of different sizes and shapes are selected or the first dummy finger and the second dummy finger are set on the first interdigital structure and the second interdigital structure, thereby improving the adaptability and flexibility of the design. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0140] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a surface acoustic wave resonator, characterized in that: The following steps are involved: A piezoelectric substrate is provided, and a first interdigital structure and a second interdigital structure are formed on the upper surface of the piezoelectric substrate, wherein the first interdigital structure comprises a first bus bar and a plurality of first finger electrodes spaced along the Y direction on the first bus bar, and the second interdigital structure comprises a second bus bar and a plurality of second finger electrodes spaced along the Y direction on the second bus bar, the first bus bar and the second bus bar are disposed opposite to each other along the X direction, the first finger electrodes and the second finger electrodes are alternately and evenly spaced in sequence along the Y direction, an end of the second finger electrode away from the second bus bar is a second end, an end of the first finger electrode away from the first bus bar is a first end, the first bus bar is spaced from the second end, and the second bus bar is spaced from the first end; forming low acoustic velocity filling grooves in the piezoelectric substrate, the low acoustic velocity filling grooves being adjacent to the first end and the second end, respectively, the low acoustic velocity filling grooves opening from the upper surface of the piezoelectric substrate and spaced apart from the bottom surface of the piezoelectric substrate; A filling layer of a non-metallic material is formed to fill the low acoustic velocity filling groove, and the X direction intersects with the Y direction.

2. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The projection of the first end in the Z direction is embedded in the projection of the low-acoustic filling groove adjacent to the first end in the Z direction, and the side of the low-acoustic filling groove close to the first bus bar is spaced from the side wall of the first end away from the first bus bar by a first preset distance, and the side of the low-acoustic filling groove away from the first bus bar is spaced from the side wall of the first end away from the first bus bar by a second preset distance; the projection of the second end in the Z direction is embedded in the projection of the low-acoustic filling groove adjacent to the second end in the Z direction, and the side of the low-acoustic filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a first preset distance, and the side of the low-acoustic filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a second preset distance, and the Z direction is perpendicular to the plane formed by the X direction and the Y direction.

3. The method for manufacturing a surface acoustic wave resonator according to claim 2, characterized in that: The first bus bar is also provided with a plurality of first fake fingers which are arranged at intervals and correspond to the second finger electrodes in the X direction, and the projection of the first fake fingers in the Z direction is located between the first bus bar and the projection of the low acoustic velocity filling groove adjacent to the second end in the Z direction; the second bus bar is also provided with a plurality of second fake fingers which are arranged at intervals and correspond to the first finger electrodes in the X direction, and the projection of the second fake fingers in the Z direction is located between the second bus bar and the projection of the low acoustic velocity filling groove adjacent to the first end in the Z direction.

4. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The side of the low-acoustic velocity filling groove adjacent to the first end away from the first bus bar is flush with the side wall of the first end away from the first bus bar in the Y direction, and the side of the low-acoustic velocity filling groove close to the first bus bar is spaced a third preset distance from the side wall of the first end away from the first bus bar in the X direction; the side of the low-acoustic velocity filling groove adjacent to the second end away from the second bus bar is flush with the side wall of the second end away from the second bus bar in the Y direction, and the side of the low-acoustic velocity filling groove close to the second bus bar is spaced a third preset distance from the side wall of the second end away from the second bus bar in the X direction.

5. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: An edge of the low-acoustic-velocity filling groove adjacent to the first end close to the first bus bar is flush with a side wall of the first end away from the first bus bar in the Y direction, and an edge of the low-acoustic-velocity filling groove away from the first bus bar is spaced apart from a side wall of the first end away from the first bus bar by a fourth preset distance in the X direction; an edge of the low-acoustic-velocity filling groove adjacent to the second end close to the second bus bar is flush with a side wall of the second end away from the second bus bar in the Y direction, and an edge of the low-acoustic-velocity filling groove away from the second bus bar is spaced apart from a side wall of the second end away from the second bus bar by a fourth preset distance in the X direction.

6. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The side of the low-acoustic velocity filling groove adjacent to the first end away from the first bus bar coincides with the projection of the edge of the second bus bar close to the first end in the Z direction, and the side of the low-acoustic velocity filling groove close to the first bus bar is spaced from the side wall of the first end away from the first bus bar by a fifth preset distance; the side of the low-acoustic velocity filling groove adjacent to the second end away from the second bus bar coincides with the projection of the edge of the first bus bar close to the second end in the Z direction, and the side of the low-acoustic velocity filling groove close to the second bus bar is spaced from the side wall of the second end away from the second bus bar by a fifth preset distance.

7. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The depth of the low acoustic velocity filling groove is less than λ, wherein λ is the wavelength of the surface acoustic wave.

8. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The material of the filling layer includes at least one of silicon dioxide, silicon nitride, glass, silicon oxynitride, and tantalum oxide.

9. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: The surface acoustic wave resonator is further provided with a temperature compensation layer, and the temperature compensation layer at least covers the exposed surfaces of the first interdigital structure and the second interdigital structure.

10. The method for manufacturing a surface acoustic wave resonator according to claim 9, characterized in that: The material of the filling layer is the same as that of the temperature compensation layer.

11. The method for manufacturing a surface acoustic wave resonator according to claim 1, characterized in that: A passivation layer is also provided in the surface acoustic wave resonator, and the passivation layer covers the exposed surfaces of the first interdigital structure and the second interdigital structure.

12. A surface acoustic wave resonator, characterized in that: The surface acoustic wave resonator is manufactured by using the method for manufacturing a surface acoustic wave resonator according to any one of claims 1 to 11.

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