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. The surface acoustic wave resonator includes a piezoelectric substrate, interdigital transducers, a first load structure, a second load structure and an insulating structure; the interdigital transducers are disposed on one side surface of the piezoelectric substrate, and the interdigital transducers include a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode extend along a second direction and are cross-arranged and arranged along a first direction; the insulating structure is disposed on one side of the long finger electrodes; the first load structure is disposed on a side of the insulating structure away from the long finger electrodes; the second load structure is disposed on a side of the long finger electrodes with the insulating structure, and the orthographic projections of the first load structure and the second load structure on the piezoelectric substrate at least partially overlap with the orthographic projection of at least one long finger electrode on the piezoelectric substrate. The present invention can suppress the transverse mode and improve the Q value of the surface acoustic wave resonator.

Description

Technical Field

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

[0002] A surface acoustic wave resonator (SAWR) is a resonant device that utilizes the propagation of surface acoustic waves (SAW) in a crystal. SAW is a mechanical wave that propagates through surface vibrations generated on the crystal surface. SAWR makes use of the special structure and material properties of the crystal to enable the formation of resonance phenomena of surface acoustic waves in the crystal. SAWR has broad application prospects in the fields of communication, sensing, navigation, medical treatment, and the Internet of Things. Its high quality factor, low insertion loss, and stability make it an ideal choice in many applications.

[0003] The working principle of SAWR is to utilize the piezoelectric effect to generate mechanical vibrations, thereby generating surface acoustic waves on the crystal surface, and realizing specific frequency vibration modes through resonance phenomena. In some cases, due to the characteristics of the material or the design of the structure, SAWR may generate transverse mode vibrations. The transverse mode refers to the transverse vibration mode generated in the crystal, which is different from the longitudinal vibration mode of SAWR. The generation of the transverse mode may lead to performance changes or instability of SAWR. Therefore, attention needs to be paid to suppressing the generation of the transverse mode during the design and manufacture of SAWR to ensure its stability and performance. Summary of the Invention

[0004] The present application provides a temperature-compensated surface acoustic wave resonator, a filter and a manufacturing method thereof, so as to solve problems such as increased insertion loss, distorted frequency response, increased bandwidth, and cross-coupling caused by transverse parasitic modes.

[0005] In a first aspect, the present application provides a temperature-compensated surface acoustic wave resonator, including:

[0006] A piezoelectric substrate;

[0007] An interdigital transducer disposed on one side surface of the piezoelectric substrate. The interdigital transducer includes a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode extend along a second direction and are arranged along a first direction; the first long finger electrode and the second long finger electrode are cross-set along the second direction;

[0008] At least one insulating structure disposed on one side of the long finger electrode;

[0009] At least one first load structure is disposed on a side of the insulating structure away from the long finger electrode, and a positive projection of the first load structure on the piezoelectric substrate overlaps at least partially with a positive projection of at least one of the long finger electrodes on the piezoelectric substrate;

[0010] At least one second load structure is disposed on a side of the long finger electrode with the insulating structure, and a positive projection of the second load structure on the piezoelectric substrate overlaps at least partially with a positive projection of at least one of the long finger electrodes on the piezoelectric substrate;

[0011] The first direction intersects with the second direction.

[0012] Preferably, along the second direction, the first long finger electrode includes a first end portion on a side close to the second long finger electrode and a second end portion on a side away from the second long finger electrode;

[0013] At least a part of the positive projection of the second load structure on the piezoelectric substrate overlaps with the positive projection of the first end portion on the piezoelectric substrate; along the second direction, the second long finger electrode includes a third end portion on a side close to the first long finger electrode and a fourth end portion on a side away from the first long finger electrode;

[0014] At least a part of the positive projection of the first load structure on the piezoelectric substrate overlaps with the positive projection of the third end portion on the piezoelectric substrate.

[0015] Preferably, the interdigital transducer further includes bus bars, and the bus bars include a first bus bar and a second bus bar;

[0016] Both the first bus bar and the second bus bar extend along the second direction and are disposed opposite to each other along the first direction;

[0017] The second end portion of the first long finger electrode is connected to the first bus bar;

[0018] The fourth end portion of the second long finger electrode is connected to the second bus bar.

[0019] Preferably, the first long finger electrode and the second long finger electrode have equal lengths along the second direction.

[0020] Preferably, the first long finger electrode and the second long finger electrode have equal widths along the first direction.

[0021] Preferably, the temperature compensated surface acoustic wave resonator further includes a temperature compensation layer;

[0022] The temperature compensation layer is disposed on a side of the interdigital transducer away from the piezoelectric substrate.

[0023] Preferably, the temperature-compensated surface acoustic wave resonator further includes a metal connection thickening layer;

[0024] The metal connection thickening layer is disposed on a side of the bus bar away from the piezoelectric substrate.

[0025] In a second aspect, the present application further provides a temperature-compensated filter, including the temperature-compensated surface acoustic wave resonator according to any one of the first aspect.

[0026] In a third aspect, the present application further provides a method for manufacturing a temperature-compensated surface acoustic wave resonator, including:

[0027] Providing a piezoelectric substrate;

[0028] Fabricating an interdigital transducer on one surface of the piezoelectric substrate;

[0029] The interdigital transducer includes a bus bar and a plurality of long finger electrodes, the long finger electrodes include 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 cross-arranged along the first direction; the widths of the long finger electrodes along the first direction are equal;

[0030] Fabricating an insulating layer on a surface of the long finger electrode away from the piezoelectric substrate;

[0031] Fabricating a first load structure on a surface of the insulating layer away from the piezoelectric substrate;

[0032] Fabricating a second load structure on a surface of the long finger electrode away from the piezoelectric substrate;

[0033] Fabricating a temperature compensation layer on a surface of the interdigital transducer away from the piezoelectric substrate, the temperature compensation layer covering at least a part of the surfaces of the insulating layer, the first load structure, the second load structure, the interdigital transducer, and the piezoelectric substrate;

[0034] Fabricating a metal connection thickening layer on a surface of the bus bar away from the piezoelectric substrate;

[0035] The first direction intersects with the second direction.

[0036] In a fourth aspect, the present application further provides a method for manufacturing a temperature-compensated surface acoustic wave resonator, including:

[0037] Providing a piezoelectric substrate;

[0038] Etch the piezoelectric substrate to form a first groove structure and a second groove structure; the depth of the first groove structure is greater than the depth of the second groove structure;

[0039] Fabricate a first load structure and a second load structure in the first groove structure and the second groove structure respectively; the thickness of the second load structure is equal to the depth of the second groove structure;

[0040] Fabricate an insulating layer on the surface of the first load structure away from the piezoelectric substrate; the thickness of the insulating layer is equal to the difference in depth between the first groove structure and the second groove structure;

[0041] Fabricate an interdigital transducer on the surface of the piezoelectric substrate close to the first groove structure;

[0042] The interdigital transducer includes a bus bar and a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode 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 first direction; the widths of the long finger electrodes along the first direction are equal;

[0043] Fabricate a temperature compensation layer on the surface of the interdigital transducer away from the piezoelectric substrate, and the temperature compensation layer covers at least a part of the surfaces of the interdigital transducer and the piezoelectric substrate;

[0044] Fabricate a metal connection thickening layer on the surface of the bus bar away from the piezoelectric substrate;

[0045] The first direction intersects with the second direction.

[0046] In a fifth aspect, the present application also provides a method for fabricating a temperature-compensated surface acoustic wave resonator, including:

[0047] Provide a piezoelectric substrate;

[0048] Etch the piezoelectric substrate to form a first groove structure and a second groove structure; the depth of the first groove structure is equal to the depth of the second groove structure;

[0049] Fabricate a first load structure and a second load structure in the first groove structure and the second groove structure respectively; the thickness of the first load structure is equal to the depth of the first groove structure; the thickness of the second load structure is equal to the depth of the second groove structure;

[0050] Fabricate an insulating layer on the surface of the first load structure;

[0051] Fabricate an interdigital transducer on one surface of the piezoelectric substrate close to the first groove structure; the interdigital transducer covers at least a part of the surfaces of the first load structure and the insulating layer;

[0052] The interdigital transducer includes bus bars and a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode 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 to cross each other along the first direction; the widths of the long finger electrodes along the first direction are equal;

[0053] Fabricate a temperature compensation layer on one surface of the interdigital transducer away from the piezoelectric substrate, and the temperature compensation layer covers at least a part of the surfaces of the interdigital transducer, the insulating layer and the piezoelectric substrate;

[0054] Fabricate a metal connection thickening layer on one surface of the bus bar away from the piezoelectric substrate;

[0055] The first direction intersects with the second direction.

[0056] In a sixth aspect, the present application further provides a method for fabricating a temperature-compensated surface acoustic wave resonator, including:

[0057] Provide a piezoelectric substrate;

[0058] Fabricate a first load structure and a second load structure on one surface of the piezoelectric substrate;

[0059] Fabricate an insulating layer on one surface of the first load structure away from the piezoelectric substrate;

[0060] Fabricate an interdigital transducer on one surface of the piezoelectric substrate close to the first load structure; the interdigital transducer covers at least a part of the surfaces of the first load structure, the second load structure and the insulating layer;

[0061] The interdigital transducer includes bus bars and a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode 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 to cross each other along the first direction; the widths of the long finger electrodes along the first direction are equal;

[0062] Fabricate a temperature compensation layer on one surface of the interdigital transducer away from the piezoelectric substrate, and the temperature compensation layer covers at least a part of the surfaces of the interdigital transducer, the insulating layer, the first load structure and the piezoelectric substrate;

[0063] A metal connection thickening layer is fabricated on the side surface of the bus bar away from the piezoelectric substrate;

[0064] The first direction intersects with the second direction.

[0065] The temperature-compensated surface acoustic wave resonator, filter and manufacturing method thereof provided by the embodiments of the present invention, wherein the temperature-compensated surface acoustic wave resonator includes a piezoelectric substrate, interdigital transducers, a first load structure, a second load structure and an insulating structure; the interdigital transducers are arranged on one side surface of the piezoelectric substrate, and the interdigital transducers include a plurality of long finger electrodes, and the long finger electrodes include a first long finger electrode and a second long finger electrode; both the first long finger electrode and the second long finger electrode extend along the second direction and are cross-arranged and arranged along the first direction; the insulating structure is arranged on one side of the long finger electrodes; the first load structure is arranged on the side of the insulating structure away from the long finger electrodes; the second load structure is arranged on the side of the long finger electrodes with the insulating structure, and the orthographic projections of the first load structure and the second load structure on the piezoelectric substrate at least partially overlap with the orthographic projection of at least one long finger electrode on the piezoelectric substrate. By providing the first load structure and the second load structure, the present invention can increase the acting force of the long finger electrodes on the piezoelectric substrate, and further can change the propagation speed of the surface acoustic wave, so that the sound velocity in the area where the first load structure and the second load structure are provided is less than the sound velocity in the area where the first load structure and the second load structure are not provided, and further can suppress the transverse mode and improve the Q value of the temperature-compensated surface acoustic wave resonator. Description of the Drawings

[0066] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0067] Figure 1 is a sectional view of a temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0068] Figure 2 is a sectional view of another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0069] Figure 3 is a sectional view of yet another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0070] Figure 4 is a sectional view of yet another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0071] Figure 5It is a top view of a temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0072] Figure 6 It is a top view of another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0073] Figure 7 It is a top view of yet another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0074] Figure 8 It is a top view of yet another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0075] Figure 9 It is a top view of yet another temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application;

[0076] Figure 10 It is a test result diagram of the temperature-compensated surface acoustic wave resonator provided by an embodiment of the present invention and the temperature-compensated surface acoustic wave resonator in the prior art. Detailed implementation manners

[0077] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

[0078] Terms such as "first" and "second" in the specification, claims, and the above-mentioned drawings of the present application are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such used data may be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order different from that shown or described herein.

[0079] As Figures 1 to 9 shown, the temperature-compensated surface acoustic wave resonator provided by an embodiment of the present application includes: a piezoelectric substrate 1, an interdigital transducer 2, at least one first load structure 3, at least one second load structure 4, and at least one insulating structure 5.

[0080] Exemplarily, the material of the piezoelectric substrate 1 may be lithium niobate or lithium tantalate.

[0081] The interdigital transducer 2 is disposed on one side surface of the piezoelectric substrate 1. 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. Both the first long finger electrode 211 and the second long finger electrode 212 extend along the second direction Y and are arranged along the first direction X, respectively forming a comb-like structure. The first long finger electrode 211 and the second long finger electrode 212 are cross-arranged along the second direction Y. Exemplarily, the materials of the long finger electrodes 21 can all be copper, aluminum, titanium, tungsten or silver. The first direction X intersects with the second direction Y.

[0082] The insulating structure 5 is disposed on one side of the long finger electrode 21. It can be understood that, as Figure 1 shown, the insulating structure 5 can also be disposed on the side of the long finger electrode 21 away from the piezoelectric substrate 1. As Figures 2 to 4 shown, the insulating structure 5 can also be disposed on the side of the long finger electrode 21 close to the piezoelectric substrate 1. The setting of the insulating structure 5 can effectively isolate adjacent long finger electrodes 21 and prevent short circuits or interference phenomena between adjacent long finger electrodes 21.

[0083] As Figures 1 to 9 shown, the first load structure 3 is disposed on the side of the insulating structure 5 away from the long finger electrode 21, and the orthographic projection of the first load structure 3 on the piezoelectric substrate 1 overlaps at least partially with the orthographic projection of at least one of the long finger electrodes 21 on the piezoelectric substrate 1. It can be understood that, as Figures 2 to 4 shown, the first load structure 3 can be disposed on the side surface of the long finger electrode 21 close to the piezoelectric substrate 1. As Figure 1 shown, the first load structure 3 can also be disposed on the side surface of the long finger electrode 21 away from the piezoelectric substrate 1. Exemplarily, the material of the first load structure 3 can be different from the material of the long finger electrode 21, and the first load structure 3 can adopt a metal material or a metal oxide material.

[0084] As Figures 1 to 9As shown, the second load structure 4 is disposed on the side of the long finger electrode 21 with the insulating structure 5, and the orthographic projection of the second load structure 4 on the piezoelectric substrate 1 overlaps at least partially with the orthographic projection of at least one of the long finger electrodes 21 on the piezoelectric substrate 1; it can be understood that the second load structure 4 can be disposed on the surface of the long finger electrode 21 close to the piezoelectric substrate 1 or on the surface of the long finger electrode 21 away from the piezoelectric substrate 1. Exemplarily, the material of the second load structure 4 can be different from the material of the long finger electrode 21, and the second load structure 4 can be made of a metal material or a metal oxide material.

[0085] It should be noted that the number, area, and shape of the first load structure 3 and the second load structure 4 are not limited in the embodiments of the present invention. On the one hand, this can strengthen the suppression effect on the transverse mode, and on the other hand, it can diversify the temperature-compensated surface acoustic wave filter. For the convenience of illustration, in the embodiments of the present invention, the shapes of the first load structure 3 and the second load structure 4 are set to be rectangular. Exemplarily, the shapes of the first load structure 3 and the second load structure 4 can also be circular, trapezoidal, regular polygons, or irregular polygons, etc. The embodiments of the present invention do not specifically limit the shapes of the first load structure 3 and the second load structure 4.

[0086] By providing the first load structure 3 and the second load structure 4, the acting force of the long finger electrode 21 on the piezoelectric substrate 1 can be increased, thereby changing the propagation speed of the surface acoustic wave, so that the acoustic velocity in the area where the first load structure 3 and the second load structure 4 are provided is less than that in the area where the first load structure 3 and the second load structure 4 are not provided, and thus the transverse mode can be suppressed and the Q value of the temperature-compensated surface acoustic wave resonator can be improved.

[0087] Preferably, along the second direction Y, 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; along the second direction Y, 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;

[0088] Such as Figures 5 to 9As shown, at least a part of the positive projection of the second load structure 4 on the piezoelectric substrate 1 overlaps with the positive projection of the first end on the piezoelectric substrate 1; at least a part of the positive projection of the first load structure 3 on the piezoelectric substrate 1 overlaps with the positive projection of the third end on the piezoelectric substrate 1. It can be understood that the minimum overlapping area between the positive projection of the first load structure 3 on the piezoelectric substrate 1 and the positive projection of the first long finger electrode 211 on the piezoelectric substrate 1 is the area of the first end. Similarly, the minimum overlapping area between the positive projection of the second load structure 4 on the piezoelectric substrate 1 and the positive projection of the second long finger electrode 212 on the piezoelectric substrate 1 is the area of the third end. The setting methods of the first load structure 3 and the second load structure 4 are simple and have a large degree of freedom in setting, and the setting methods are flexible.

[0089] In the embodiment as Figure 5 shown, the positive projection of the first load structure 3 on the piezoelectric substrate 1 is equal to the positive projection of the first long finger electrode 211 on the piezoelectric substrate 1, and the positive projection of the second load structure 4 on the piezoelectric substrate 1 is equal to the positive projection of the second long finger electrode 212 on the piezoelectric substrate 1, that is, the areas and shapes of the first load structure 3, the second load structure 4, the first end, and the third end are all the same. In the embodiment as Figures 6 to 9 shown, the positive projection of the first load structure 3 on the piezoelectric substrate 1 is larger than the positive projection of the first long finger electrode 211 on the piezoelectric substrate 1, and the positive projection of the second load structure 4 on the piezoelectric substrate 1 is larger than the positive projection of the second long finger electrode 212 on the piezoelectric substrate 1. It can be understood that the embodiments as Figures 5 to 9 shown are only partial embodiments disclosed by the present invention, rather than limitations thereto.

[0090] Preferably, the interdigital transducer 2 further includes bus bars 22, and the bus bars 22 include a first bus bar 221 and a second bus bar 222; the bus bars 22 can receive an alternating current signal. When an alternating current signal of a certain frequency is applied to the bus bars 22, surface acoustic waves can be generated in the temperature-compensated surface acoustic wave resonator;

[0091] Both the first bus bar 221 and the second bus bar 222 extend along the second direction Y and are oppositely arranged along the first direction X;

[0092] The second end of the first long finger electrode 211 is connected to the first bus bar 221;

[0093] The fourth end of the second long finger electrode 212 is connected to the second bus bar 222.

[0094] Preferably, the first long finger electrode 211 and the second long finger electrode 212 have the same length extending along the second direction Y. In this way, on the one hand, the setting method is simple, and on the other hand, the suppression effect on the transverse mode can be enhanced.

[0095] Preferably, the first long finger electrode 211 and the second long finger electrode 212 have the same width along the first direction X. In this way, on the one hand, the setting method is simple, and on the other hand, the suppression effect on the transverse mode can be enhanced.

[0096] Preferably, the temperature-compensated surface acoustic wave resonator further includes a temperature compensation layer 6; the temperature compensation layer 6 is disposed on a side of the interdigital transducer 2 away from the piezoelectric substrate 1. Exemplarily, the material of the temperature compensation layer 6 can be silicon dioxide, silicon nitride, or a silicon-containing dielectric film such as silicon nitride. The setting of the temperature compensation layer 6 can avoid the influence of temperature change on the resonance frequency of the temperature-compensated surface acoustic wave resonator, and improve the temperature stability and reliability of the resonator. It should be noted that, in order to enable the resonator to have better temperature stability, a positive temperature coefficient material can be used to compensate for the adverse effects brought by the piezoelectric material. Such a temperature-compensated surface acoustic wave resonator can reduce the adverse effects brought by temperature drift.

[0097] Preferably, the temperature-compensated surface acoustic wave resonator further includes a metal connection thickening layer 7; the metal connection thickening layer 7 is disposed on a side of the bus bar 22 away from the piezoelectric substrate 1. Exemplarily, the material of the metal connection thickening layer 7 can be titanium, aluminum, copper, gold, or silver. The setting of the metal connection thickening layer 7 can play a role in heat dissipation, and at the same time can reduce the electrical loss and improve the quality factor of the resonator.

[0098] Based on the same inventive concept, an embodiment of the present invention further provides a temperature-compensated filter, including the temperature-compensated surface acoustic wave resonator in the above embodiment. Therefore, the filter provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be elaborated here.

[0099] As Figure 1 shown, based on the same inventive concept, an embodiment of the present invention further provides a manufacturing method of a temperature-compensated surface acoustic wave resonator, including:

[0100] Providing a piezoelectric substrate 1;

[0101] Fabricating an interdigital transducer 2 on one surface of the piezoelectric substrate 1;

[0102] The interdigital transducer 2 includes a bus bar 22 and 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 in a crosswise manner along the first direction X. The widths of the long finger electrodes 21 along the first direction X are equal.

[0103] An insulating layer 5 is fabricated on the surface of the long finger electrode 21 away from the piezoelectric substrate 1.

[0104] A first load structure 3 is fabricated on the surface of the insulating layer 5 away from the piezoelectric substrate 1.

[0105] A second load structure 4 is fabricated on the surface of the long finger electrode 21 away from the piezoelectric substrate 1.

[0106] A temperature compensation layer 6 is fabricated on the surface of the interdigital transducer 2 away from the piezoelectric substrate 1. The temperature compensation layer 6 covers at least a part of the surfaces of the insulating layer 5, the first load structure 3, the second load structure 4, the interdigital transducer 2, and the piezoelectric substrate 1.

[0107] A metal connection thickening layer 7 is fabricated on the surface of the bus bar 22 away from the piezoelectric substrate 1.

[0108] The first direction X intersects with the second direction Y.

[0109] By using the fabrication method described in this embodiment, the temperature-compensated surface acoustic wave resonator described in the above embodiment can be fabricated. By setting the first load structure 3 and the second load structure 4, the fabrication method can increase the acting force of the long finger electrode 21 on the piezoelectric substrate 1, and further can change the propagation speed of the surface acoustic wave, such that the acoustic velocity in the region where the first load structure 3 and the second load structure 4 are set is less than the acoustic velocity in the region where the first load structure 3 and the second load structure 4 are not set, thereby suppressing the transverse mode and improving the Q value of the temperature-compensated surface acoustic wave resonator.

[0110] As Figure 2 shown, based on the same inventive concept, an embodiment of the present invention further provides a fabrication method of a temperature-compensated surface acoustic wave resonator, including:

[0111] Providing a piezoelectric substrate 1;

[0112] Etching the piezoelectric substrate 1 to form a first groove structure 11 and a second groove structure 12. The depth of the first groove structure 11 is greater than the depth of the second groove structure 12.

[0113] Manufacture a first load structure 3 and a second load structure 4 in the first groove structure 11 and the second groove structure 12 respectively; the thickness of the second load structure 4 is equal to the depth of the second groove structure 12;

[0114] Manufacture an insulating layer 5 on the surface of the first load structure 3 away from the piezoelectric substrate 1; the thickness of the insulating layer 5 is equal to the difference between the depths of the first groove structure 11 and the second groove structure 12;

[0115] Manufacture an interdigital transducer 2 on the surface of the piezoelectric substrate 1 close to the first groove structure 11;

[0116] The interdigital transducer 2 includes a bus bar 22 and a plurality of long finger electrodes 21, and the long finger electrodes 21 include a first long finger electrode 211 and a second long finger electrode 212; both the first long finger electrode 211 and the second long finger electrode 212 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 first direction X; the widths of the long finger electrodes 21 along the first direction X are equal;

[0117] Manufacture a temperature compensation layer 6 on the surface of the interdigital transducer 2 away from the piezoelectric substrate 1, and the temperature compensation layer 6 covers at least a part of the surfaces of the interdigital transducer 2 and the piezoelectric substrate 1;

[0118] Manufacture a metal connection thickening layer 7 on the surface of the bus bar 22 away from the piezoelectric substrate 1;

[0119] The first direction X intersects with the second direction Y.

[0120] By using the manufacturing method described in this embodiment, the temperature-compensated surface acoustic wave resonator described in the above embodiment can be manufactured. By setting the first load structure 3 and the second load structure 4, the manufacturing method can increase the acting force of the long finger electrodes 21 on the piezoelectric substrate 1, and further can change the propagation speed of the surface acoustic wave, so that the acoustic velocity in the area where the first load structure 3 and the second load structure 4 are set is less than the acoustic velocity in the area where the first load structure 3 and the second load structure 4 are not set, and further can suppress the transverse mode and improve the Q value of the temperature-compensated surface acoustic wave resonator.

[0121] As Figure 3 shown, based on the same inventive concept, the embodiment of the present invention also provides a manufacturing method of a temperature-compensated surface acoustic wave resonator, including:

[0122] Provide a piezoelectric substrate 1;

[0123] Etch the piezoelectric substrate 1 to form a first groove structure 11 and a second groove structure 12; the depth of the first groove structure 11 is equal to the depth of the second groove structure 12;

[0124] Fabricate a first load structure 3 and a second load structure 4 in the first groove structure 11 and the second groove structure 12 respectively; the thickness of the first load structure 3 is equal to the depth of the first groove structure 11; the thickness of the second load structure 4 is equal to the depth of the second groove structure 12;

[0125] Fabricate an insulating layer 5 on the surface of the first load structure 3;

[0126] Fabricate an interdigital transducer 2 on one side surface of the piezoelectric substrate 1 close to the first groove structure 11; the interdigital transducer 2 covers at least a part of the surface of the first load structure 3 and the insulating layer 5;

[0127] The interdigital transducer 2 includes a bus bar 22 and a plurality of long finger electrodes 21, and the long finger electrodes 21 include a first long finger electrode 211 and a second long finger electrode 212; both the first long finger electrode 211 and the second long finger electrode 212 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 in a cross pattern along the first direction X; the widths of the long finger electrodes 21 along the first direction X are equal;

[0128] Fabricate a temperature compensation layer 6 on one side surface of the interdigital transducer 2 away from the piezoelectric substrate 1, and the temperature compensation layer 6 covers at least a part of the surface of the interdigital transducer 2, the insulating layer 5 and the piezoelectric substrate 1;

[0129] Fabricate a metal connection thickening layer 7 on one side surface of the bus bar 22 away from the piezoelectric substrate 1;

[0130] The first direction X intersects with the second direction Y.

[0131] By using the manufacturing method described in this embodiment, the temperature-compensated surface acoustic wave resonator described in the above embodiment can be manufactured. By setting the first load structure 3 and the second load structure 4, the manufacturing method can increase the acting force of the long finger electrode 21 on the piezoelectric substrate 1, and further change the propagation speed of the surface acoustic wave, so that the acoustic velocity in the area where the first load structure 3 and the second load structure 4 are set is less than that in the area where the first load structure 3 and the second load structure 4 are not set, thereby suppressing the transverse mode and improving the Q value of the temperature-compensated surface acoustic wave resonator.

[0132] As Figure 4As shown, based on the same inventive concept, an embodiment of the present invention further provides a method for manufacturing a temperature-compensated surface acoustic wave resonator, including:

[0133] Providing a piezoelectric substrate 1;

[0134] Fabricating a first load structure 3 and a second load structure 4 on one side surface of the piezoelectric substrate 1;

[0135] Fabricating an insulating layer 5 on the side surface of the first load structure 3 away from the piezoelectric substrate 1;

[0136] Fabricating an interdigital transducer 2 on the side surface of the piezoelectric substrate 1 close to the first load structure 3; the interdigital transducer 2 covers at least a part of the surfaces of the first load structure 3, the second load structure 4, and the insulating layer 5;

[0137] The interdigital transducer 2 includes a bus bar 22 and a plurality of long finger electrodes 21, and the long finger electrodes 21 include a first long finger electrode 211 and a second long finger electrode 212; both the first long finger electrode 211 and the second long finger electrode 212 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 cross-set along the first direction X; the widths of the long finger electrodes 21 along the first direction X are equal;

[0138] Fabricating a temperature compensation layer 6 on the side surface of the interdigital transducer 2 away from the piezoelectric substrate 1, and the temperature compensation layer 6 covers at least a part of the surfaces of the interdigital transducer 2, the insulating layer 5, the first load structure 3, and the piezoelectric substrate 1;

[0139] Fabricating a metal connection thickening layer 7 on the side surface of the bus bar 22 away from the piezoelectric substrate 1;

[0140] The first direction X intersects with the second direction Y.

[0141] By using the manufacturing method described in this embodiment, the temperature-compensated surface acoustic wave resonator described in the above embodiment can be manufactured. By setting the first load structure 3 and the second load structure 4, the manufacturing method can increase the acting force of the long finger electrodes 21 on the piezoelectric substrate 1, and further can change the propagation speed of the surface acoustic wave, so that the acoustic velocity in the area where the first load structure 3 and the second load structure 4 are set is less than that in the area where the first load structure 3 and the second load structure 4 are not set, and further can suppress the transverse mode and improve the Q value of the temperature-compensated surface acoustic wave resonator.

[0142] Figure 10The figure shows the test results of the temperature-compensated surface acoustic wave resonator provided by the embodiments of the present invention and the temperature-compensated surface acoustic wave resonator in the prior art. Refer to Figure 10 , Figure 10 in which the abscissa represents the frequency, Figure 10 and the ordinate represents the admittance. The red curve represents the admittance curve of the temperature-compensated surface acoustic wave resonator in the prior art, and the blue curve represents the admittance curve of the temperature-compensated surface acoustic wave resonator provided by this embodiment. The left peak in the red curve and the blue curve is the resonance point, and the right peak is the anti-resonance point. As can be seen from Figure 10 , there are obvious transverse mode clutter between the resonance point and the anti-resonance point in the admittance curve of the temperature-compensated surface acoustic wave resonator provided by the prior art, while the admittance curve obtained by using the temperature-compensated surface acoustic wave resonator provided by this embodiment is very smooth between the resonance point and the anti-resonance point, and the transverse mode suppression effect is obvious.

[0143] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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: Piezoelectric substrate (1); An interdigital transducer (2) is arranged on a side surface of the piezoelectric substrate (1), 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 (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 second direction (Y); at least one insulating structure (5) disposed on one side of the long finger electrode (21); At least one first load structure (3) is arranged on a side of the insulating structure (5) away from the long finger electrode (21), and an orthographic projection of the first load structure (3) on the piezoelectric substrate (1) at least partially overlaps with an orthographic projection of at least one of the long finger electrodes (21) on the piezoelectric substrate (1); at least one second load structure (4) is arranged on a side of the long finger electrode (21) having the insulating structure (5), and an orthographic projection of the second load structure (4) on the piezoelectric substrate (1) at least partially overlaps with an orthographic projection of at least one of the long finger electrodes (21) on the piezoelectric substrate (1); The first direction (X) intersects with the second direction (Y).

2. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: Along the second direction (Y), 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); The orthographic projection of at least part of the second load structure (4) on the piezoelectric substrate (1) overlaps with the orthographic projection of the first end on the piezoelectric substrate (1); along the second direction (Y), the second long finger electrode (212) comprises a third end close to the first long finger electrode (211) and a fourth end away from the first long finger electrode (211); An orthographic projection of at least part of the first load structure (3) on the piezoelectric substrate (1) overlaps with an orthographic projection of the third end on the piezoelectric substrate (1).

3. The temperature-compensated surface acoustic wave resonator according to claim 2, characterized in that: The interdigital transducer (2) further comprises a bus bar (22), wherein the bus bar (22) comprises a first bus bar (221) and a second bus bar (222); The first bus bar (221) and the second bus bar (222) 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 (221); The fourth end of the second long finger electrode (212) is connected to the second bus bar (222).

4. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The first long finger electrode (211) and the second long finger electrode (212) have the same length extending along the second direction (Y).

5. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: The widths of the first long finger electrode (211) and the second long finger electrode (212) along the first direction (X) are equal.

6. The temperature-compensated surface acoustic wave resonator according to claim 1, characterized in that: Also includes a temperature compensation layer (6); The temperature compensation layer (6) is arranged on a side of the interdigital transducer (2) away from the piezoelectric substrate (1).

7. The temperature-compensated surface acoustic wave resonator according to claim 3, characterized in that: It also includes a metal connection thickening layer (7); The metal connection thickening layer (7) is arranged on a side of the bus bar (22) away from the piezoelectric substrate (1).

8. A temperature compensation filter, characterized in that: The invention comprises the temperature-compensated surface acoustic wave resonator according to any one of claims 1 to 7.

9. A method for manufacturing a temperature-compensated surface acoustic wave resonator, characterized in that: include: Providing a piezoelectric substrate (1); An interdigital transducer (2) is fabricated on one side surface of the piezoelectric substrate (1); The interdigital transducer (2) comprises a bus bar (22) and a plurality of long finger electrodes (21), wherein 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 (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 widths of the long finger electrodes (21) along the first direction (X) are equal; An insulating layer (5) is formed on the surface of the long finger electrode (21) which is away from the piezoelectric substrate (1); A first load structure (3) is fabricated on a surface of the insulating layer (5) that is away from the piezoelectric substrate (1); A second load structure (4) is fabricated on a surface of the long finger electrode (21) that is away from the piezoelectric substrate (1); A temperature compensation layer (6) is formed on a surface of the interdigital transducer (2) away from the piezoelectric substrate (1), wherein the temperature compensation layer (6) covers at least a portion of the surface of the insulating layer (5), the first load structure (3), the second load structure (4), the interdigital transducer (2) and the piezoelectric substrate (1); A metal connection thickening layer (7) is formed on the surface of the bus bar (22) on the side away from the piezoelectric substrate (1); The first direction (X) intersects with the second direction (Y).

10. A method for manufacturing a temperature-compensated surface acoustic wave resonator, characterized in that: include: Providing a piezoelectric substrate (1); Etching the piezoelectric substrate (1) to form a first groove structure (11) and a second groove structure (12); the depth of the first groove structure (11) is greater than the depth of the second groove structure (12); A first load structure (3) and a second load structure (4) are respectively manufactured in the first groove structure (11) and the second groove structure (12); the thickness of the second load structure (4) is equal to the depth of the second groove structure (12); An insulating layer (5) is formed on a surface of the first load structure (3) that is away from the piezoelectric substrate (1); the thickness of the insulating layer (5) is equal to the difference between the depth of the first groove structure (11) and the depth of the second groove structure (12); An interdigital transducer (2) is fabricated on a surface of the piezoelectric substrate (1) on one side close to the first groove structure (11); The interdigital transducer (2) comprises a bus bar (22) and a plurality of long finger electrodes (21), wherein 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 (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 widths of the long finger electrodes (21) along the first direction (X) are equal; A temperature compensation layer (6) is formed on a surface of the interdigital transducer (2) that is away from the piezoelectric substrate (1), wherein the temperature compensation layer (6) covers at least a portion of the surface of the interdigital transducer (2) and the piezoelectric substrate (1); A metal connection thickening layer (7) is formed on the surface of the bus bar (22) on the side away from the piezoelectric substrate (1); The first direction (X) intersects with the second direction (Y).

11. A method for manufacturing a temperature-compensated surface acoustic wave resonator, characterized in that: include: Providing a piezoelectric substrate (1); Etching the piezoelectric substrate (1) to form a first groove structure (11) and a second groove structure (12); the depth of the first groove structure (11) is equal to the depth of the second groove structure (12); A first load structure (3) and a second load structure (4) are respectively manufactured in the first groove structure (11) and the second groove structure (12); the thickness of the first load structure (3) is equal to the depth of the first groove structure (11); and the thickness of the second load structure (4) is equal to the depth of the second groove structure (12); Producing an insulating layer (5) on the surface of the first load structure (3); An interdigital transducer (2) is fabricated on a surface of the piezoelectric substrate (1) close to the first groove structure (11); the interdigital transducer (2) covers at least a portion of the surface of the first load structure (3) and the insulating layer (5); The interdigital transducer (2) comprises a bus bar (22) and a plurality of long finger electrodes (21), wherein 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 (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 widths of the long finger electrodes (21) along the first direction (X) are equal; A temperature compensation layer (6) is formed on a surface of the interdigital transducer (2) that is away from the piezoelectric substrate (1), wherein the temperature compensation layer (6) covers at least a portion of the surface of the interdigital transducer (2), the insulating layer (5) and the piezoelectric substrate (1); A metal connection thickening layer (7) is formed on the surface of the bus bar (22) on the side away from the piezoelectric substrate (1); The first direction (X) intersects with the second direction (Y).

12. A method for manufacturing a temperature-compensated surface acoustic wave resonator, characterized in that: include: Providing a piezoelectric substrate (1); A first load structure (3) and a second load structure (4) are fabricated on one side surface of the piezoelectric substrate (1); An insulating layer (5) is formed on a surface of the first load structure (3) that is away from the piezoelectric substrate (1); An interdigital transducer (2) is fabricated on a surface of the piezoelectric substrate (1) close to the first load structure (3); the interdigital transducer (2) covers at least a portion of the surface of the first load structure (3), the second load structure (4) and the insulating layer (5); The interdigital transducer (2) comprises a bus bar (22) and a plurality of long finger electrodes (21), wherein 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 (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 widths of the long finger electrodes (21) along the first direction (X) are equal; A temperature compensation layer (6) is formed on a surface of the interdigital transducer (2) away from the piezoelectric substrate (1), wherein the temperature compensation layer (6) covers at least a portion of the surface of the interdigital transducer (2), the insulating layer (5), the first load structure (3) and the piezoelectric substrate (1); A metal connection thickening layer (7) is formed on the surface of the bus bar (22) on the side away from the piezoelectric substrate (1); The first direction (X) intersects with the second direction (Y).

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