A temperature-compensated surface acoustic wave resonator, filter and manufacturing method thereof

Abstract

The present application provides a temperature-compensated surface acoustic wave resonator, a filter and a manufacturing method thereof, wherein the resonator comprises a substrate, an interdigital transducer, a reflection grating region, a first load structure, a second load structure and a temperature compensation layer; the interdigital transducer comprises a plurality of long finger electrodes; the reflection grating region comprises a plurality of reflection gratings; the first load structure is arranged on a side of the long finger electrode away from the substrate along the thickness direction, and the orthographic projection of the first load structure on the substrate overlaps with the orthographic projection of the long finger electrode on the substrate at least in part; the second load structure is arranged on a side of the reflection grating away from the substrate along the thickness direction, and the orthographic projection of the second load structure on the substrate overlaps with the orthographic projection of the reflection grating on the substrate at least in part. By arranging the first load structure and the second load structure, the present application can increase the force of the long finger electrode and the reflection grating on the substrate, change the propagation speed of the surface acoustic wave, thereby suppressing the lateral mode clutter and improving the Q value of the temperature-compensated surface acoustic wave resonator.

Description

Technical Field

[0001] The present application relates to the technical field of filters, and in particular to a temperature-compensated surface acoustic wave resonator, a filter and a manufacturing method thereof. Background Art

[0002] Surface acoustic wave (SAW) technology is a technology that uses mechanical vibrations of piezoelectric materials to propagate waves on the surface to transmit signals. Surface acoustic wave filters (SAW filters) are devices that use the characteristics of surface acoustic waves to filter signals. They have the advantages of small size, light weight, low cost, high reliability, and easy integration. They are widely used in microwave frequency band electronic devices such as mobile communications, satellite communications, and radar systems. The field of filter design is a complex field involving circuit design, signal processing, and material science. In the microwave frequency band, filter design needs to consider many factors, such as insertion loss, out-of-band suppression, reliability, stability, and manufacturing process. The field of microelectronics manufacturing technology involves technologies such as semiconductor manufacturing processes, component assembly, and welding.

[0003] Existing surface acoustic wave filters usually use a periodic reflection grating structure, which can produce a phase difference during the propagation of the surface acoustic wave, thereby achieving a filtering function. However, this structure has some problems, such as large insertion loss, unsatisfactory out-of-band suppression, and poor reliability and stability.

[0004] Therefore, there is an urgent need for a surface acoustic wave resonator and a filter that can solve the above problems. Summary of the invention

[0005] The present application provides a temperature-compensated surface acoustic wave resonator, a filter and a manufacturing method thereof, which are used to solve the problems of large insertion loss and unsatisfactory out-of-band suppression of the surface acoustic wave filter.

[0006] In a first aspect, the present application provides a temperature compensated surface acoustic wave resonator, comprising:

[0007] substrate;

[0008] An interdigital transducer is arranged on a side surface of the substrate along the thickness direction, the interdigital transducer comprises a plurality of long finger electrodes, the long finger electrodes comprise a first long finger electrode and a second long finger electrode; the first long finger electrode and the second long finger electrode both extend along the second direction and are arranged along the first direction; the first long finger electrode and the second long finger electrode are arranged crosswise along the second direction;

[0009] A reflection grating region is arranged on a surface of one side of the substrate along the thickness direction and is in the same plane as the IDT; along the first direction, the reflection grating region is at least arranged on one side of the IDT; the reflection grating region includes a plurality of reflection gratings extending along the second direction; the reflection gratings are arranged at predetermined intervals in the first direction, and at least one of the reflection gratings is a short-circuit grating;

[0010] at least one first load structure, disposed on a side of the long finger electrode away from the substrate along the thickness direction, and an orthographic projection of the first load structure on the substrate at least partially overlaps with an orthographic projection of the long finger electrode on the substrate;

[0011] at least one second load structure, disposed on a side of the reflective grating away from the substrate along the thickness direction, and an orthographic projection of the second load structure on the substrate at least partially overlaps with an orthographic projection of the reflective grating on the substrate;

[0012] A temperature compensation layer is provided on a side of the substrate where the interdigital transducer is provided along the thickness direction;

[0013] The first direction intersects the second direction.

[0014] Preferably, the first long finger electrode comprises a first end portion close to a side of the second long finger electrode and a second end portion away from a side of the second long finger electrode;

[0015] An orthographic projection of at least a portion of the first load structure on the substrate overlaps with an orthographic projection of the first end on the substrate;

[0016] The second long finger electrode comprises a third end portion close to a side of the first long finger electrode and a fourth end portion away from a side of the first long finger electrode;

[0017] An orthographic projection of at least a portion of the first load structure on the substrate overlaps with an orthographic projection of the third end on the substrate.

[0018] Preferably, the IDT further comprises a first bus bar and a second bus bar;

[0019] The first bus bar and the second bus bar both extend along the second direction and are arranged opposite to each other along the first direction;

[0020] The second end of the first long finger electrode is connected to the first bus bar;

[0021] The fourth end of the second long finger electrode is connected to the second bus bar.

[0022] Preferably, the reflective grid area further includes a third bus bar and a fourth bus bar;

[0023] The third bus bar and the fourth bus bar both extend along the second direction and are arranged opposite to each other along the first direction;

[0024] The reflector comprises a fifth end portion close to one side of the third bus bar and a sixth end portion close to the fourth bus bar;

[0025] At least a portion of the orthographic projection of the second load structure on the substrate overlaps with the orthographic projection of the fifth end on the substrate;

[0026] At least a portion of an orthographic projection of the second load structure on the substrate overlaps with an orthographic projection of the sixth end on the substrate.

[0027] Preferably, a dimension of the first load structure along the thickness direction is a first dimension L, and a value range of the first dimension L is: 0.01λ≤L≤0.02λ, wherein λ is the wavelength of the surface acoustic wave.

[0028] Preferably, a dimension of the second load structure along the second direction is a second dimension J, and a value range of the second dimension J is: 0.3λ≤J≤0.9λ.

[0029] Preferably, a dimension of the first load structure along the second direction is a third dimension M, and a value range of the third dimension M is: 0.3λ≤M≤0.7λ.

[0030] Preferably, the second size J and the third size M satisfy the following relationship: M≤J≤1.2M.

[0031] Preferably, along the second direction, an edge of the second load structure on a side away from the center of the aperture is aligned with an edge of the first load structure on a side away from the center of the aperture.

[0032] Preferably, the reflection grating further comprises a polarity alternating finger stripe portion, and along the first direction, the polarity alternating finger stripe portion is arranged on a side of the reflection grating region close to the interdigital transducer.

[0033] Preferably, the first load structure and the second load structure are arranged on a surface of the temperature compensation layer away from the substrate along the thickness direction, or the first load structure and the second load structure are arranged inside the temperature compensation layer along the thickness direction.

[0034] In a second aspect, the present application further provides a temperature-compensated surface acoustic wave filter, comprising the temperature-compensated surface acoustic wave resonator described in any one of the first aspects.

[0035] In a third aspect, the present application also provides a method for manufacturing a temperature-compensated surface acoustic wave resonator, comprising:

[0036] Providing a substrate; the substrate is a piezoelectric substrate, and the material used includes lithium niobate or lithium tantalate;

[0037] Fabricating an interdigital transducer and a reflective grating region on one side surface of the substrate along the thickness direction;

[0038] The interdigital transducer comprises a first bus bar, a second bus bar and a plurality of long finger electrodes, wherein the long finger electrodes comprise a first long finger electrode and a second long finger electrode; the first long finger electrode and the second long finger electrode both extend along a second direction and are arranged along a first direction; the first long finger electrode and the second long finger electrode are arranged crosswise along the first direction; the material used for the long finger electrodes comprises any one of titanium, chromium, silver, copper, molybdenum, platinum, tungsten and aluminum and a combination thereof;

[0039] The reflection grid area includes a plurality of reflection grids, the reflection grids extend along the second direction and are arranged along the first direction; at least one of the reflection grids is a short-circuit grid;

[0040] A first load structure is fabricated on a side of the long finger electrode away from the substrate in the thickness direction; the orthographic projection of the first load structure on the substrate at least partially overlaps with the orthographic projection of the long finger electrode on the substrate; the material used for the first load structure includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and a combination thereof;

[0041] A second load structure is fabricated on a side of the reflective grating away from the substrate in the thickness direction; the orthographic projection of the second load structure on the substrate at least partially overlaps with the orthographic projection of the reflective grating on the substrate; the material used for the second load structure includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and any combination thereof;

[0042] A temperature compensation layer is formed on one side of the substrate where the IDT is provided in the thickness direction, and the temperature compensation layer covers the first load structure, the second load structure, the IDT and at least a portion of the surface of the substrate; the material used for the temperature compensation layer includes a dielectric material with a positive temperature coefficient such as silicon dioxide or silicon nitride;

[0043] The first direction intersects the second direction.

[0044] Preferably, the first load structure and the second load structure are arranged on a surface of the temperature compensation layer away from the substrate along the thickness direction, or the first load structure and the second load structure are arranged inside the temperature compensation layer.

[0045] Preferably, the reflection grating further comprises a polarity alternating finger portion, and along the first direction, the polarity alternating finger portion is arranged on a side of the short-circuit grating close to the IDT.

[0046] The temperature-compensated surface acoustic wave resonator provided by the present application includes a substrate, an interdigital transducer, a reflection grid area, a first load structure, a second load structure and a temperature compensation layer; the interdigital transducer includes a plurality of long finger electrodes; the reflection grid area includes a plurality of reflection grids, at least one of which is a short-circuit grid; the first load structure is arranged on a side of the long finger electrode away from the substrate along the thickness direction, and the positive projection of the first load structure on the substrate overlaps with the positive projection of the long finger electrode on the substrate at least in part; the second load structure is arranged on a side of the reflection grid away from the substrate along the thickness direction, and the positive projection of the second load structure on the substrate overlaps with the positive projection of the reflection grid on the substrate at least in part. By arranging the first load structure and the second load structure, the present application can increase the force of the long finger electrode and the reflection grid on the substrate, thereby changing the propagation speed of the surface acoustic wave, so that the sound speed of the surface acoustic wave in the area where the first load structure and the second load structure are arranged is less than the sound speed of the area where the first load structure and the second load structure are not arranged, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature-compensated surface acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0048] Figure 1 is a top view of the temperature-compensated surface acoustic wave resonator provided in Example 1 of the present application;

[0049] Figure 2 is a top view of a temperature-compensated surface acoustic wave resonator provided in Example 2 of the present application;

[0050] Figure 3 is a top view of a temperature-compensated surface acoustic wave resonator provided in Embodiment 3 of the present application;

[0051] Figure 4 is a top view of a temperature-compensated surface acoustic wave resonator provided in Embodiment 4 of the present application;

[0052] Figure 5 is a cross-section of a temperature-compensated surface acoustic wave resonator provided in an embodiment of the present application Figure 1 ;

[0053] Figure 6 is a cross-section of a temperature-compensated surface acoustic wave resonator provided in an embodiment of the present application Figure 2 ;

[0054] Figure 7 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 1 ;

[0055] Figure 8 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 2 ;

[0056] Fig. 9 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 3 ;

[0057] Fig.10 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 4 .

[0058] Explanation of symbols:

[0059] 1. Substrate; 2. IDT; 21. Long finger electrode; 211. First long finger electrode; 212. Second long finger electrode; 22. First bus bar; 23. Second bus bar; 3. Reflection grid area; 31. Reflection grid; 311. Short-circuit grid; 312. Polarity alternating finger section; 32. Third bus bar; 33. Fourth bus bar; 4. First load structure; 5. Second load structure; 6. Temperature compensation layer; L, first size; J, second size; M, third size; X, first direction; Y, second direction. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0062] First, as Figures 1 to 6 As shown, the present application provides a temperature compensated surface acoustic wave resonator, comprising:

[0063] Substrate 1; the substrate 1 is a piezoelectric substrate, and the material used includes lithium niobate or lithium tantalate;

[0064] An interdigital transducer 2 is arranged on a side surface of the substrate 1 along the thickness direction, the interdigital transducer 2 includes a plurality of long finger electrodes 21, the long finger electrodes 21 include a first long finger electrode 211 and a second long finger electrode 212; the first long finger electrode 211 and the second long finger electrode 212 both extend along the second direction Y and are arranged along the first direction X; the first long finger electrode 211 and the second long finger electrode 212 are arranged crosswise along the second direction Y; the material used for the long finger electrode 21 includes any one of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, aluminum and a combination thereof;

[0065] A reflection grating region 3 is arranged on a side surface of the substrate 1 along the thickness direction and is in the same plane as the interdigital transducer 2; along the first direction X, the reflection grating region 3 is at least arranged on one side of the interdigital transducer 2; the reflection grating region 3 includes a plurality of reflection gratings 31 extending along the second direction Y; the reflection gratings 31 are arranged at predetermined intervals in the first direction X, and at least one of the reflection gratings 31 is a short-circuit grating 311; the reflection gratings 31 can be used to reflect surface acoustic waves to prevent surface acoustic waves from leaking, and adding the reflection gratings 31 can enhance the selectivity of the filter, expand the bandwidth of the filter, reduce the size of the filter, and improve the stability of the filter;

[0066] at least one first load structure 4, arranged on a side of the long finger electrode 21 away from the substrate 1 along the thickness direction, and the orthographic projection of the first load structure 4 on the substrate 1 at least partially overlaps with the orthographic projection of the long finger electrode 21 on the substrate 1; the material used for the first load structure 4 includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and any combination thereof;

[0067] at least one second load structure 5, arranged on a side of the reflective grating 31 away from the substrate 1 along the thickness direction, and the orthographic projection of the second load structure 5 on the substrate 1 at least partially overlaps with the orthographic projection of the reflective grating 31 on the substrate 1; the material used for the second load structure 5 includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and any combination thereof;

[0068] The temperature compensation layer 6 is arranged on the side of the substrate 1 along the thickness direction where the interdigital transducer 2 is arranged; the material used for the temperature compensation layer 6 includes a dielectric material with a positive temperature coefficient such as silicon dioxide or silicon nitride; the setting of the temperature compensation layer 6 can prevent temperature changes from affecting the resonant frequency of the temperature compensated surface acoustic wave resonator, thereby improving the temperature stability and reliability of the resonator.

[0069] The first direction X and the second direction Y intersect.

[0070] By setting the first load structure 4 and the second load structure 5, the present application can increase the force of the long finger electrode 21 and the reflection grid 31 on the substrate 1, thereby changing the propagation speed of the surface acoustic wave, so that the sound speed of the surface acoustic wave in the area where the first load structure 4 and the second load structure 5 are set is smaller than the sound speed of the area where the first load structure 4 and the second load structure 5 are not set, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature compensated surface acoustic wave resonator.

[0071] Preferably, the first long finger electrode 211 includes a first end close to the second long finger electrode 212 and a second end away from the second long finger electrode 212; at least part of the orthographic projection of the first load structure 4 on the substrate 1 overlaps with the orthographic projection of the first end on the substrate 1; the second long finger electrode 212 includes a third end close to the first long finger electrode 211 and a fourth end away from the first long finger electrode 211; at least part of the orthographic projection of the first load structure 4 on the substrate 1 overlaps with the orthographic projection of the third end on the substrate 1. By setting the first load structure 4, the propagation speed of the surface acoustic wave can be changed, so that the sound speed of the surface acoustic wave in the area where the first load structure 4 is set is less than the sound speed of the area where the first load structure 4 is not set, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature compensated surface acoustic wave resonator.

[0072] Preferably, the IDT 2 further includes a first bus bar 22 and a second bus bar 23; the first bus bar 22 and the second bus bar 23 both extend along the second direction Y and are arranged opposite to each other along the first direction X; the second end of the first long finger electrode 211 is connected to the first bus bar 22; and the fourth end of the second long finger electrode 212 is connected to the second bus bar 23. The first bus bar 22 can receive an AC signal, and when an AC signal of a certain frequency is applied to the first bus bar 22, a surface acoustic wave can be generated in the temperature compensated surface acoustic wave resonator.

[0073] Preferably, the reflection grating area 3 further includes a third bus bar 32 and a fourth bus bar 33; the third bus bar 32 and the fourth bus bar 33 both extend along the second direction Y and are arranged opposite to each other along the first direction X; the reflection grating 31 includes a fifth end close to the third bus bar 32 and a sixth end close to the fourth bus bar 33; at least a part of the orthographic projection of the second load structure 5 on the substrate 1 overlaps with the orthographic projection of the fifth end on the substrate 1; at least a part of the orthographic projection of the second load structure 5 on the substrate 1 overlaps with the orthographic projection of the sixth end on the substrate 1. By setting the second load structure 5, the force of the reflection grating 31 on the substrate 1 can be increased, thereby changing the propagation speed of the surface acoustic wave, so that the sound speed of the surface acoustic wave in the area where the second load structure 5 is set is less than the sound speed of the area where the second load structure 5 is not set, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature compensated surface acoustic wave resonator.

[0074] Preferably, the dimension of the first load structure 4 along the thickness direction is a first dimension L, and the value range of the first dimension L is: 0.01λ≤L≤0.02λ, where λ is the wavelength of the surface acoustic wave. Such a design can further enhance the suppression effect of the temperature compensated surface acoustic wave resonator on the lateral mode.

[0075] Preferably, the dimension of the second load structure 5 along the second direction Y is a second dimension J, and the value range of the second dimension J is: 0.3λ≤J≤0.9λ. Such a design can further enhance the suppression effect of the temperature compensated surface acoustic wave resonator on the lateral mode.

[0076] Preferably, the dimension of the first load structure 4 along the second direction Y is a third dimension M, and the value range of the third dimension M is: 0.3λ≤M≤0.7λ. Such a design can further enhance the suppression effect of the temperature compensated surface acoustic wave resonator on the lateral mode.

[0077] Preferably, the second dimension J and the third dimension M satisfy the following relationship: M≤J≤1.2 M. Such a design can further enhance the suppression effect of the temperature compensated surface acoustic wave resonator on the lateral mode.

[0078] Preferably, along the second direction Y, the edge of the second load structure 5 on the side away from the aperture center is aligned with the edge of the first load structure 4 on the side away from the aperture center. In this way, on the one hand, the setting method is simple, easy to design and maintain, and on the other hand, the suppression effect of transverse mode clutter can be further enhanced.

[0079] Preferably, the reflection grating 31 further includes a polarity alternating finger portion 312, and along the first direction X, the polarity alternating finger portion 312 is arranged on a side of the reflection grating area 3 close to the IDT 2. By arranging the polarity alternating finger portion 312 on a side of the reflection grating area 3 close to the IDT 2, the selective filtering effect of the signal can be improved, the distortion and interference of the signal can be reduced, and the reliability of the surface acoustic wave filter can be improved.

[0080] Preferably, if Figure 5 As shown, the first load structure 4 and the second load structure 5 are arranged on a side surface of the temperature compensation layer 6 away from the substrate 1 along the thickness direction, or, as shown Figure 6 As shown, the first load structure 4 and the second load structure 5 are arranged inside the temperature compensation layer 6 along the thickness direction. Figures 1 to 4 The cross-sectional views of the embodiments shown are as follows Figure 5 Such a design can further enhance the suppression effect of the temperature-compensated surface acoustic wave resonator on the lateral mode.

[0081] In the second aspect, based on the same inventive concept, the present application also provides a temperature-compensated surface acoustic wave filter, including the temperature-compensated surface acoustic wave resonator described in any embodiment of the first aspect. By setting the first load structure 4 and the second load structure 5, the force of the long finger electrode 21 and the reflective grating 31 on the substrate 1 can be increased, thereby changing the propagation speed of the surface acoustic wave, so that the sound speed of the surface acoustic wave in the area where the first load structure 4 and the second load structure 5 are set is less than the sound speed of the area where the first load structure 4 and the second load structure 5 are not set, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature-compensated surface acoustic wave resonator.

[0082] In a third aspect, based on the same inventive concept, the present application also provides a method for manufacturing a temperature-compensated surface acoustic wave resonator, comprising:

[0083] Providing a substrate 1; the substrate 1 is a piezoelectric substrate, and the material used includes lithium niobate or lithium tantalate;

[0084] An interdigital transducer 2 and a reflective grating region 3 are fabricated on one side surface of the substrate 1 along the thickness direction;

[0085] The interdigital transducer 2 includes a first bus bar 22, a second bus bar 23 and a plurality of long finger electrodes 21, wherein the long finger electrodes 21 include a first long finger electrode 211 and a second long finger electrode 212; the first long finger electrode 211 and the second long finger electrode 212 both extend along a second direction Y and are arranged along a first direction X; the first long finger electrode 211 and the second long finger electrode 212 are arranged crosswise along the first direction X; the material used for the long finger electrode 21 includes any one of titanium, chromium, silver, copper, molybdenum, platinum, tungsten, and aluminum, and a combination thereof;

[0086] The reflection grid area 3 includes a plurality of reflection grids 31 , and the reflection grids 31 extend along the second direction Y and are arranged along the first direction X; at least one of the reflection grids 31 is a short-circuit grid 311 ;

[0087] A first load structure 4 is fabricated on a side of the long finger electrode 21 away from the substrate 1 in the thickness direction; the orthographic projection of the first load structure 4 on the substrate 1 at least partially overlaps with the orthographic projection of the long finger electrode 21 on the substrate 1; the material of the first load structure 4 includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and a combination thereof;

[0088] A second load structure 5 is fabricated on a side of the reflective grating 31 away from the substrate 1 in the thickness direction; the orthographic projection of the second load structure 5 on the substrate 1 at least partially overlaps with the orthographic projection of the reflective grating 31 on the substrate 1; the material of the second load structure 5 includes any one of titanium, copper, aluminum, chromium, silver, molybdenum and a combination thereof;

[0089] A temperature compensation layer 6 is formed on one side of the substrate 1 along the thickness direction where the IDT 2 is provided, and the temperature compensation layer 6 covers the first load structure 4, the second load structure 5, the IDT 2 and at least a portion of the surface of the substrate 1; the material used for the temperature compensation layer 6 includes a dielectric material with a positive temperature coefficient such as silicon dioxide or silicon nitride;

[0090] The first direction X and the second direction Y intersect.

[0091] By adopting the manufacturing method described in this embodiment, the temperature-compensated surface acoustic wave resonator described in the first aspect can be manufactured. The method can increase the force of the long finger electrode 21 and the reflective grating 31 on the substrate 1 by setting the first load structure 4 and the second load structure 5, thereby changing the propagation speed of the surface acoustic wave, so that the sound speed of the surface acoustic wave in the area where the first load structure 4 and the second load structure 5 are set is less than the sound speed of the area where the first load structure 4 and the second load structure 5 are not set, thereby suppressing the transverse mode clutter, reducing the surface acoustic wave leakage and energy loss, and improving the Q value of the temperature-compensated surface acoustic wave resonator.

[0092] Preferably, if Figure 5 As shown, the first load structure 4 and the second load structure 5 are arranged on the surface of the temperature compensation layer 6 away from the substrate 1 along the thickness direction, or, as shown Figure 6 As shown, the first load structure 4 and the second load structure 5 are arranged inside the temperature compensation layer 6. Figures 1 to 4 The cross-sectional views of the embodiments shown are as follows Figure 5 Such a design can further enhance the suppression effect of the temperature-compensated surface acoustic wave resonator on the lateral mode.

[0093] Preferably, the reflection grating 31 further includes a polarity alternating finger portion 312, and along the first direction X, the polarity alternating finger portion 312 is arranged on a side of the short-circuit grating 311 close to the IDT 2. By arranging the polarity alternating finger portion 312 on a side of the reflection grating region 3 close to the IDT 2, the selective filtering effect of the signal can be improved, the distortion and interference of the signal can be reduced, and the reliability of the surface acoustic wave filter can be improved.

[0094] Figure 7 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 1 ,refer to Figure 7 , Figure 7 The horizontal axis represents frequency, and the vertical axis represents admittance. The blue curve represents the admittance curve of the surface acoustic wave resonator in the prior art, and dB(Y(3,3)) refers to the input admittance parameter of the resonator port 1 in the prior art; the black curve represents the admittance curve of the surface acoustic wave resonator provided in the second embodiment of the present invention, and dB(Y(1,1)) refers to the input admittance parameter of the resonator port 1 in the second embodiment of the present invention; the red curve represents the admittance curve of the surface acoustic wave resonator provided in the third embodiment of the present invention, and dB(Y(2,2)) refers to the input admittance parameter of the resonator port 1 in the third embodiment of the present invention. The left peak of the three curves is the resonance point, and the right peak is the anti-resonance point. Figure 7 It can be seen that the admittance curve of the surface acoustic wave resonator provided by the prior art has obvious lateral mode noise between the resonance point and the anti-resonance point, while the admittance curve obtained by the surface acoustic wave resonator provided by Examples 2 and 3 of the present application is very smooth between the resonance point and the anti-resonance point, and the lateral mode suppression effect is obvious.

[0095] Figure 8 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 2 ,refer to Figure 8 , Figure 8The horizontal axis represents the frequency, and the vertical axis represents the real part of the admittance. The blue curve represents the real part of the admittance curve of the surface acoustic wave resonator in the prior art, and dB(real(Y(3,3))) refers to the real part of the logarithm of the input admittance parameter of the resonator port 1 in the prior art; the black curve represents the real part of the admittance curve of the surface acoustic wave resonator provided in the second embodiment, and dB(real(Y(1,1))) refers to the real part of the logarithm of the input admittance parameter of the resonator port 1 in the second embodiment of the present invention; the red curve represents the real part of the admittance curve of the surface acoustic wave resonator provided in the third embodiment, and dB(real(Y(2,2))) refers to the real part of the logarithm of the input admittance parameter of the resonator port 1 in the third embodiment of the present invention. The peak on the left side of the three curves is the resonance point, from Figure 8 It can be seen that the admittance curve of the surface acoustic wave resonator provided by the prior art has obvious transverse mode noise on the right side of the resonance point, while the real part of the admittance curve obtained by using the surface acoustic wave resonator provided by Examples 2 and 3 of the present application is very smooth on the right side of the resonance point, and the transverse mode suppression effect is obvious.

[0096] Fig. 9 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 3 ,refer to Fig. 9 , Fig. 9 The horizontal axis represents frequency, and the vertical axis represents quality factor. The blue curve represents the admittance curve of the surface acoustic wave resonator in the prior art, and Qbode3 refers to the input quality factor of the resonator port 1 in the prior art; the black curve represents the admittance curve of the surface acoustic wave resonator provided in the second embodiment of the present invention, and Qbode1 refers to the input quality factor of the resonator port 1 in the second embodiment of the present invention; the red curve represents the admittance curve of the surface acoustic wave resonator provided in the third embodiment of the present invention, and Qbode2 refers to the input quality factor of the resonator port 1 in the third embodiment of the present invention. The peaks in the three curves are the peak values ​​of the resonator quality factors, from Fig. 9 It can be seen that the peak values ​​of the quality factors of the surface acoustic wave resonators provided in the second and third embodiments of the present application are substantially equivalent to the peak values ​​of the quality factors of the surface acoustic wave resonators provided in the prior art.

[0097] Fig.10 The test results of the temperature compensation surface acoustic wave resonator provided by the embodiment of the present application are compared with those of the prior art. Figure 4 ,refer to Fig.10 , Fig.10The horizontal axis represents frequency, and the vertical axis represents return loss. The blue curve represents the return loss curve of the surface acoustic wave resonator in the prior art, and dB(abs(S(3,3))) refers to the logarithm of the absolute value of the return loss of the resonator port 1 in the prior art; the black curve represents the return loss curve of the surface acoustic wave resonator provided in the second embodiment of the present invention, and dB(abs(S(1,1))) refers to the logarithm of the absolute value of the return loss of the resonator port 1 in the second embodiment of the present invention; the red curve represents the return loss curve of the surface acoustic wave resonator provided in the third embodiment of the present invention, and dB(abs(S(2,2))) refers to the logarithm of the absolute value of the return loss of the resonator port 1 in the third embodiment of the present invention. The smoothness of the return loss in the frequency band from the resonant frequency to the anti-resonant frequency represents the effect of suppressing the lateral mode, from Fig.10 It can be seen that the return loss curve of the surface acoustic wave resonator provided by the prior art has obvious lateral mode noise between the resonance point and the anti-resonance point, while the return loss curve obtained by the surface acoustic wave resonator provided by Examples 2 and 3 of the present application is very smooth between the resonance point and the anti-resonance point, and the lateral mode suppression effect is obvious.

[0098] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A temperature-compensated surface acoustic wave resonator, characterized in that: include: Substrate (1); An interdigital transducer (2) is arranged on a side surface of the substrate (1) along the thickness direction, the interdigital transducer (2) comprising a plurality of long finger electrodes (21), the long finger electrodes (21) comprising a first long finger electrode (211) and a second long finger electrode (212); the first long finger electrode (211) and the second long finger electrode (212) both extend along a second direction and are arranged along the first direction; the first long finger electrode (211) and the second long finger electrode (212) are arranged crosswise along the second direction; A reflection grating region (3) is arranged on a surface of one side of the substrate (1) along the thickness direction and is in the same plane as the interdigital transducer (2); along the first direction, the reflection grating region (3) is at least arranged on one side of the interdigital transducer (2); the reflection grating region (3) comprises a plurality of reflection gratings (31) extending along the second direction; in the first direction, the reflection gratings (31) are arranged at predetermined intervals, and at least one of the reflection gratings (31) is a short-circuit grating (311); at least one first load structure (4), arranged on a side of the long finger electrode (21) away from the substrate (1) in the thickness direction, and an orthographic projection of the first load structure (4) on the substrate (1) at least partially overlaps with an orthographic projection of the long finger electrode (21) on the substrate (1); at least one second load structure (5) arranged on a side of the reflective grating (31) away from the substrate (1) in the thickness direction, and an orthographic projection of the second load structure (5) on the substrate (1) at least partially overlaps with an orthographic projection of the reflective grating (31) on the substrate (1); A temperature compensation layer (6) is arranged on a side of the substrate (1) along the thickness direction where the interdigital transducer (2) is arranged; The first direction intersects the second direction.

2. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: Along the second direction, the first long finger electrode (211) comprises a first end portion close to a side of the second long finger electrode (212) and a second end portion away from a side of the second long finger electrode (212); An orthographic projection of at least part of the first load structure (4) on the substrate (1) overlaps with an orthographic projection of the first end on the substrate (1); The second long finger electrode (212) comprises a third end portion close to a side of the first long finger electrode (211) and a fourth end portion far from a side of the first long finger electrode (211); An orthographic projection of at least part of the first load structure (4) on the substrate (1) overlaps with an orthographic projection of the third end on the substrate (1).

3. The temperature-compensated surface acoustic wave resonator according to claim 2, characterized in that: The interdigital transducer (2) further comprises a first bus bar (22) and a second bus bar (23); The first bus bar (22) and the second bus bar (23) both extend along the second direction and are arranged opposite to each other along the first direction; The second end of the first long finger electrode (211) is connected to the first bus bar (22); The fourth end of the second long finger electrode (212) is connected to the second bus bar (23).

4. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The reflective grid area (3) further comprises a third bus bar (32) and a fourth bus bar (33); The third bus bar (32) and the fourth bus bar (33) both extend along the second direction and are arranged opposite to each other along the first direction; The reflective grid (31) comprises a fifth end portion close to one side of the third bus bar (32) and a sixth end portion close to the fourth bus bar (33); The orthographic projection of at least part of the second load structure (5) on the substrate (1) overlaps with the orthographic projection of the fifth end on the substrate (1); An orthographic projection of at least part of the second load structure (5) on the substrate (1) overlaps with an orthographic projection of the sixth end on the substrate (1).

5. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The dimension of the first load structure (4) along the thickness direction is a first dimension L, and the value range of the first dimension L is: 0.01λ≤L≤0.02λ, wherein λ is the wavelength of the surface acoustic wave.

6. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The dimension of the second load structure (5) along the second direction is a second dimension J, and the value range of the second dimension J is: 0.3λ≤J≤0.9λ, wherein λ is the wavelength of the surface acoustic wave.

7. The temperature-compensated surface acoustic wave resonator according to claim 6, characterized in that: The dimension of the first load structure (4) along the second direction is a third dimension M, and the value range of the third dimension M is: 0.3λ≤M≤0.7λ, wherein λ is the wavelength of the surface acoustic wave.

8. The temperature-compensated surface acoustic wave resonator according to claim 7, characterized in that: The second size J and the third size M satisfy the following relationship: M≤J≤1.2M.

9. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: Along the second direction, the edge of the second load structure (5) on a side away from the center of the aperture is aligned with the edge of the first load structure (4) on a side away from the center of the aperture.

10. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The reflection grating (31) further comprises a polarity alternating finger strip portion (312), and along the first direction, the polarity alternating finger strip portion (312) is arranged on a side of the reflection grating region (3) close to the interdigital transducer (2).

11. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The first load structure (4) and the second load structure (5) are arranged on a surface of the temperature compensation layer (6) along the thickness direction away from the substrate (1), or the first load structure (4) and the second load structure (5) are arranged inside the temperature compensation layer (6) along the thickness direction.

12. A temperature-compensated surface acoustic wave filter, characterized in that: The invention comprises the temperature-compensated surface acoustic wave resonator according to any one of claims 1 to 11.

13. A method for manufacturing a temperature-compensated surface acoustic wave resonator, characterized in that: include: Providing a substrate (1); An interdigital transducer (2) and a reflective grating region (3) are fabricated on one side surface of the substrate (1) along the thickness direction; The interdigital transducer (2) comprises a first bus bar (22), a second bus bar (23) and a plurality of long finger electrodes (21); the long finger electrodes (21) comprise a first long finger electrode (211) and a second long finger electrode (212); the first long finger electrode (211) and the second long finger electrode (212) both extend along a second direction and are arranged along a first direction; the first long finger electrode (211) and the second long finger electrode (212) are arranged crosswise along the first direction; The reflective grid area (3) comprises a plurality of reflective grids (31), wherein the reflective grids (31) extend along the second direction and are arranged along the first direction; at least one of the reflective grids (31) is a short-circuit grid (311); A first load structure (4) is fabricated on a side of the long finger electrode (21) away from the substrate (1) in the thickness direction; the orthographic projection of the first load structure (4) on the substrate (1) at least partially overlaps with the orthographic projection of the long finger electrode (21) on the substrate (1); A second load structure (5) is fabricated on a side of the reflective grating (31) away from the substrate (1) in the thickness direction; the orthographic projection of the second load structure (5) on the substrate (1) at least partially overlaps with the orthographic projection of the reflective grating (31) on the substrate (1); A temperature compensation layer (6) is formed on one side of the substrate (1) along the thickness direction where the interdigital transducer (2) is provided, wherein the temperature compensation layer (6) covers at least a portion of the surface of the first load structure (4), the second load structure (5), the interdigital transducer (2) and the substrate (1); The first direction intersects the second direction.

14. The method for manufacturing a temperature-compensated surface acoustic wave resonator according to claim 13, characterized in that: The first load structure (4) and the second load structure (5) are arranged on a surface of the temperature compensation layer (6) away from the substrate (1) along the thickness direction, or the first load structure (4) and the second load structure (5) are arranged inside the temperature compensation layer (6).

15. According to the method for manufacturing a temperature-compensated surface acoustic wave resonator according to claim 13, the reflection grating (31) further comprises a polarity-alternating finger portion (312), and along the first direction, the polarity-alternating finger portion (312) is arranged on a side of the short-circuit grating (311) close to the interdigital transducer (2).

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