Resonator and radio frequency module

Abstract

The invention provides a resonator and a radio frequency module, and the resonator comprises a piezoelectric substrate, an interdigital transducer and an optimization layer. The interdigital transducer comprises an electrode finger, the electrode finger at least comprises a first electrode layer and a second electrode layer, the first electrode layer is arranged on one side of the piezoelectric substrate, and the second electrode layer is arranged on the side, away from the piezoelectric substrate, of the first electrode layer. The optimization layer is arranged on the side, provided with the electrode fingers, of the piezoelectric substrate and covers the electrode fingers and the piezoelectric substrate. The electrode mass M of the unit length of the electrode fingers in the aperture direction is larger than 250 lambda < 2 >, the aperture direction is the extension direction of the electrode fingers, lambda is the cycle length of the interdigital transducer, the thickness of the optimization layer is larger than or equal to 50 nm, the electrode fingers are made of negative frequency temperature characteristic materials, and the optimization layer is made of positive frequency temperature characteristic materials. According to the resonator provided by the invention, miniaturization can be realized, and the problem that the temperature characteristic of the resonator is deteriorated due to the fact that the overall frequency temperature coefficient of the resonator is greatly reduced can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, and in particular to a resonator and a radio frequency module. BACKGROUND

[0002] A surface acoustic wave (SAW) resonator is a device that converts an electrical signal into an acoustic signal or converts an acoustic signal into an electrical signal. The surface acoustic wave resonator generally includes a substrate and an interdigital transducer (IDT) formed on the substrate, which can be used to convert an electrical signal into an acoustic signal or convert an acoustic signal into an electrical signal.

[0003] With the development of surface acoustic wave resonator technology, there is a higher requirement for the miniaturization of the resonator. In the related art, the technical means for realizing the miniaturization of the resonator can cause the deterioration of other performances of the resonator, for example, causing the deterioration of the temperature characteristics of the resonator. SUMMARY

[0004] Therefore, the present application provides a resonator and a radio frequency module.

[0005] The resonator provided by the first aspect of the present application comprises: a piezoelectric substrate; an interdigital transducer, the interdigital transducer comprising electrode fingers, the electrode fingers comprising at least a first electrode layer and a second electrode layer, the first electrode layer being disposed on one side of the piezoelectric substrate, and the second electrode layer being disposed on a side of the first electrode layer away from the piezoelectric substrate; an optimization layer, the optimization layer being disposed on a side of the piezoelectric substrate on which the electrode fingers are disposed, and covering the electrode fingers and the piezoelectric substrate, wherein a unit length electrode mass M of the electrode fingers in an aperture direction is greater than 250λ 2 , the aperture direction being an extension direction of the electrode fingers, λ being a period length of the interdigital transducer, a thickness of the optimization layer being greater than or equal to 50 nm, a material of the electrode fingers being a negative frequency temperature characteristic material, and a material of the optimization layer being a positive frequency temperature characteristic material.

[0006] As can be seen from the above technical solution, the resonator provided by the first aspect of the present application first sets the electrode fingers as a multi-layer thickened electrode structure comprising at least a first electrode layer and a second electrode layer, which can reduce the resistance of the electrode fingers, thereby reducing the insertion loss, improving the power tolerance and reliability, and optimizing the electrical performance of the electrode fingers by the combination of different materials without sacrificing the mechanical stability. Secondly, by setting the unit length electrode mass M of the electrode fingers in the aperture direction to be greater than 250λ 2The large-mass electrode finger formed in this way can reduce the acoustic velocity of the resonator, so that a resonator with the same function can be formed using a smaller pitch (the distance between two adjacent electrode fingers), thereby reducing the area of the resonator and achieving miniaturization of the resonator. Furthermore, by providing an optimization layer covering the electrode finger, the material of the optimization layer is a positive frequency temperature characteristic material opposite to the material property of the electrode finger, and the thickness of the optimization layer is greater than or equal to 50 nm, so that the optimization layer can compensate for the frequency temperature coefficient of the electrode finger, and can solve the problem that the overall frequency temperature coefficient (Temperature Coefficient of Frequency, TCF) of the resonator is greatly reduced due to the increase in the mass of the electrode finger, so that the frequency of the resonator changes greatly with the change in temperature, that is, the temperature characteristic deteriorates. In addition, the resonator provided in the embodiment combines the technical features of "the electrode finger includes a multi-layer thickened electrode structure of at least a first electrode layer and a second electrode layer", "the electrode mass M per unit length of the electrode finger in the aperture direction is set to be greater than 250λ 2 ", "the thickness of the optimization layer is set to be greater than or equal to 50 nm", "the material of the electrode finger is a negative frequency temperature characteristic material, and the material of the optimization layer is a positive frequency temperature characteristic material", and under the joint action of the technical features, the problems of large size of the resonator and deterioration of the temperature characteristic of the resonator are solved, so that the finished resonator has the advantages of small insertion loss, high power tolerance, high reliability, good electrical performance, small size, frequency stability, and high temperature adaptability, thereby greatly widening the application range of the resonator.

[0007] The resonator provided in the second aspect of the present application comprises: a piezoelectric substrate; an interdigital transducer, the interdigital transducer comprising an electrode finger, the electrode finger comprising at least a first electrode layer and a second electrode layer, the first electrode layer being disposed on one side of the piezoelectric substrate, and the second electrode layer being disposed on a side of the first electrode layer away from the piezoelectric substrate; an optimization layer, the optimization layer being disposed on a side of the piezoelectric substrate on which the electrode finger is disposed and covering the electrode finger and the piezoelectric substrate; wherein the thickness of the optimization layer is [50 nm, 150 nm] and is configured to compensate for the temperature coefficient of the electrode finger, so that the absolute value of the frequency temperature coefficient of the resonant frequency of the resonator and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency is less than a preset value.

[0008] From the above technical solutions, the resonator of the second aspect of the present application can reduce the resistance of the electrode finger, thereby reducing the insertion loss, improving the power tolerance and reliability, and optimizing the electrical performance of the electrode finger by combining different materials without sacrificing mechanical stability. Secondly, by setting the optimization layer to cover the electrode finger, the thickness of the optimization layer is set to [50nm, 150nm], and the optimization layer can compensate for the frequency temperature coefficient of the electrode finger, so that the absolute value of the frequency temperature coefficient of the resonant frequency of the resonator and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency is less than a predetermined value. In this way, the frequency of the resonator can be prevented from changing greatly with temperature, i.e. the problem of deteriorating temperature characteristics. In addition, the resonator of the present embodiment combines the technical features of "the electrode finger includes a multi-layer thickened electrode structure of at least a first electrode layer and a second electrode layer", "the thickness of the optimization layer is in the range of [50nm, 150nm]", and "the optimization layer is configured to compensate for the temperature coefficient of the electrode finger, so that the absolute value of the frequency temperature coefficient of the resonant frequency of the resonator and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency is less than a predetermined value". Under the joint action of the above technical features, the finished resonator has the advantages of small insertion loss, high power tolerance, high reliability, good electrical performance, frequency stability, and high temperature adaptability, thereby greatly widening the application range of the resonator.

[0009] The resonator of the third aspect of the present application comprises: a piezoelectric substrate; an interdigital transducer, the interdigital transducer comprising an electrode finger, the electrode finger comprising at least a first electrode layer and a second electrode layer, the first electrode layer being disposed on one side of the piezoelectric substrate, and the second electrode layer being disposed on a side of the first electrode layer away from the piezoelectric substrate; an optimization layer, the optimization layer being disposed on a side of the piezoelectric substrate where the electrode finger is disposed and covering the electrode finger and the piezoelectric substrate; the thickness of the optimization layer is W, the electrode mass per unit length of the electrode finger in the aperture direction is M, and the following relationship is satisfied: (m), , , wherein, is the density of the first electrode layer, is the density of the second electrode layer, is the height of the first electrode layer in the direction perpendicular to the piezoelectric substrate, L is the height of the second electrode layer along the direction perpendicular to the piezoelectric substrate, and L is the width of the bottom surface of the first electrode layer along the first direction. The first included angle is the angle formed by the bottom surface of the first electrode layer and any side surface of the first electrode layer along the aperture direction. The second included angle is the angle formed by the bottom surface of the second electrode layer and any side surface of the second electrode layer along the aperture direction, λ is the period length of the interdigital transducer, DF is the duty cycle of the electrode finger, the aperture direction is the extension direction of the electrode finger, and the first direction is the arrangement direction of the plurality of electrode fingers.

[0010] As can be seen from the above technical solutions, the resonator proposed in the third aspect of this application, firstly, by setting the electrode fingers as a multi-layered thickened electrode structure including at least a first electrode layer and a second electrode layer, can reduce the resistance of the electrode fingers, thereby reducing insertion loss and improving power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode fingers can be optimized through the combination of different materials. Secondly, by setting the thickness W of the optimized layer to satisfy a relationship with the electrode mass M per unit length along the aperture direction of the electrode fingers... (m), that is, the thickness of the optimization layer varies with the change of electrode mass M per unit length along the aperture direction of the electrode finger. In this embodiment, when the optimization layer is configured to compensate for the frequency temperature coefficient of the electrode finger, under the condition that the optimization layer compensates for the frequency temperature coefficient of the electrode finger, the excessive thickness of the optimization layer can be avoided from affecting the frequency and thickness of the resonator.

[0011] The resonator proposed in the fourth aspect of this application includes: A piezoelectric substrate, comprising a substrate layer, a piezoelectric layer, and a temperature compensation layer, wherein the piezoelectric layer and the temperature compensation layer are disposed on one side of the substrate layer, and the temperature compensation layer is disposed between the substrate layer and the piezoelectric layer; An interdigital transducer includes electrode fingers, each electrode finger comprising at least a first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the piezoelectric layer away from the temperature compensation layer, and the second electrode layer is disposed on the side of the first electrode layer away from the piezoelectric layer. An optimization layer is disposed on the side of the piezoelectric layer where the electrode fingers are disposed, and covers the electrode fingers and the piezoelectric layer; Wherein, the electrode refers to an electrode with a unit length mass M greater than 250λ along the aperture direction. 2 The aperture direction is the extension direction of the electrode fingers, λ is the period length of the interdigital transducer, and the thickness of the optimization layer is greater than or equal to 50 nm.

[0012] As can be seen from the above technical solutions, the resonator proposed in the fourth aspect of this application, firstly, by setting the electrode fingers as a multi-layered thickened electrode structure including at least a first electrode layer and a second electrode layer, can reduce the resistance of the electrode fingers, thereby reducing insertion loss and improving power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode fingers can be optimized through the combination of different materials. Secondly, by setting the electrode mass M per unit length along the aperture direction of the electrode fingers to be greater than 250λ... 2 The resulting large-mass electrode fingers can reduce the sound velocity of the resonator, allowing for the use of a smaller pitch (the distance between two adjacent electrode fingers) to construct a resonator with the same function, thereby reducing the resonator area and achieving miniaturization. Secondly, by setting the thickness of the optimization layer to be greater than or equal to 50 nm, when one of the electrode fingers and the optimization layer is made of a material with negative frequency temperature characteristics, and the other is made of a material with positive frequency temperature characteristics, this thickness of the optimization layer can compensate for the frequency temperature coefficient of the electrode fingers. This solves the problem that the increased mass of the electrode fingers leads to a significant decrease in the overall temperature coefficient of frequency (TCF) of the resonator, causing the resonator's frequency to change drastically with temperature, i.e., deterioration of temperature characteristics. Furthermore, the resonator proposed in this embodiment, by using a "multi-layer thickened electrode structure comprising at least a first electrode layer and a second electrode layer" and setting the electrode mass M per unit length along the aperture direction of the electrode fingers to be greater than 250λ, further enhances the resonator's performance. 2 By combining several technical features, such as "the thickness of the optimization layer is set to be greater than or equal to 50nm", the problem of large size of existing resonators and the derivative problem of temperature characteristic deterioration of resonators are solved. This makes the finished resonator have the advantages of low insertion loss, high power tolerance, high reliability, good electrical performance, small size, frequency stability and high temperature adaptability, thus greatly expanding the application range of resonators.

[0013] The radio frequency module proposed in the fifth aspect of this application includes the aforementioned resonator.

[0014] As can be seen from the above technical solutions, the radio frequency module proposed in the fifth aspect of this application has the following advantages because it includes the above-mentioned resonator: it can achieve miniaturization and can solve the problem that the overall temperature coefficient of frequency (TCF) of the resonator is greatly reduced due to the increased mass of the electrode fingers, which causes the temperature characteristics of the resonator to deteriorate. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a resonator proposed in one embodiment of this application; Figure 2 yes Figure 1 Schematic diagram of the cross section at the middle EE; Figure 3 yes Figure 2 A partial schematic diagram of the structure shown; Figure 4 This is a graph showing the relationship between the thickness of the optimized layer and the frequency temperature coefficient of the resonator according to an embodiment of this application. Figure 5 This is a graph showing the relationship between the thickness of the optimized layer and the frequency temperature coefficient of the resonator, as proposed in another embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0019] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] like Figure 1 and Figure 2 As shown, an embodiment of this application proposes a resonator including a piezoelectric substrate 10, an interdigital transducer 20, and an optimization layer 30. The interdigital transducer 20 includes electrode fingers 21, each electrode finger including at least a first electrode layer 211 and a second electrode layer 212. The first electrode layer 211 is disposed on one side of the piezoelectric substrate 10, and the second electrode layer 212 is disposed on the side of the first electrode layer 211 away from the piezoelectric substrate 10. The optimization layer 30 is disposed on the side of the piezoelectric substrate 10 where the electrode fingers 21 are disposed, and covers the electrode fingers 21 and the piezoelectric substrate 10. The electrode mass M per unit length of the electrode fingers 21 along the aperture direction Y is greater than 250λ. 2 The aperture direction Y is the extension direction of electrode finger 21, λ is the period length of interdigital transducer 20, the thickness of optimization layer 30 is greater than or equal to 50nm, the material of electrode finger 21 is a negative frequency temperature characteristic material, and the material of optimization layer 30 is a positive frequency temperature characteristic material.

[0023] It should be noted that the piezoelectric substrate 10 can be one of the following: a bulk crystalline substrate, a heteroepitaxial thin film substrate, or a bonded thin film substrate. A bulk crystalline substrate uses a diced single-crystal piezoelectric material film directly as the substrate; suitable single-crystal piezoelectric materials include quartz, lithium tantalate, and lithium niobate. A heteroepitaxial thin film substrate grows a piezoelectric thin film on a non-piezoelectric substrate using epitaxial growth techniques (such as magnetron sputtering or metal-organic chemical vapor deposition); representative structures include aluminum nitride / scandium-doped aluminum nitride-on-silicon and zinc oxide-on-sapphire. A bonded thin film substrate is formed by transferring a high-quality single-crystal piezoelectric thin layer onto another substrate (usually silicon) through ion implantation lift-off or smart dicing, combined with wafer bonding technology; for example, a common POI (Piezoelectric-on-Insulator) substrate.

[0024] The first electrode layer 211 and the second electrode layer 212 are both important components of the electrode finger 21. Among them, the first electrode layer 211 is the main electrode layer in the electrode finger 21, and it accounts for the largest proportion of the mass of the electrode finger 21. It has a significant impact on the sound velocity and coupling coefficient (KT-squared, KT). 2 This has a significant impact. The second electrode layer 212 is an auxiliary electrode layer in the electrode finger 21, which can optimize the conductivity of the electrode finger 21. The thickness of the first electrode layer 211 and the second electrode layer 212 can be the same or different, and the materials of the first electrode layer 211 and the second electrode layer 212 can be the same or different. The specific choice depends on the actual design requirements.

[0025] The optimization layer 30 is configured to compensate for the frequency temperature coefficient of the electrode finger 21. It should be noted that the electrode finger 21 proposed in this embodiment is, on the one hand, a multi-layered thickened electrode structure including at least a first electrode layer 211 and a second electrode layer 212; and on the other hand, the electrode mass M per unit length along the aperture direction Y is greater than 250λ. 2 The large mass of the electrodes increases the proportion of electrode fingers 21 in the total mass of the resonator. Since the material of electrode fingers 21 is a negative frequency temperature characteristic material, its frequency decreases with increasing temperature, leading to a significant reduction in the overall frequency temperature coefficient of the resonator. This results in a substantial change in the resonator's frequency with temperature variations, i.e., a deterioration in temperature characteristics. Simulation experiments show that by setting the thickness of the optimization layer 30 to 50 nm or more, the frequency temperature coefficient of electrode fingers 21 can be compensated, thereby solving the problem of deteriorated temperature characteristics of the resonator. It should be noted that the optimization layer 30 is not limited to compensating for the frequency temperature coefficient of electrode fingers 21; for example, in some other embodiments, the optimization layer 30 is also configured to protect and moisture-proof the surface of electrode fingers 21.

[0026] Specifically, the phrase "the optimization layer 30 is disposed on the side of the piezoelectric substrate 10 where the electrode fingers 21 are disposed, and covers the electrode fingers 21 and the piezoelectric substrate 10" means that the optimization layer 30 covers the upper surface of the electrode fingers 21 away from the piezoelectric substrate 10, the side surface connected to the upper surface, and the area of ​​the piezoelectric substrate 10 where the electrode fingers 21 are not disposed. It should be noted that "the optimization layer 30 covers the electrode fingers 21" can mean that the optimization layer 30 only covers the electrode fingers 21, or it can mean that the optimization layer 30 covers the entire interdigital transducer 20, since the electrode fingers 21 are part of the interdigital transducer 20 and are therefore also covered by the optimization layer 30.

[0027] The term "negative frequency temperature characteristic material" refers to a material whose frequency decreases as temperature increases and increases as temperature decreases. The term "positive frequency temperature characteristic material" refers to a material whose frequency increases as temperature increases and decreases as temperature decreases.

[0028] It should be noted that, in this embodiment, the material of the electrode finger 21 being a negative frequency temperature characteristic material means that the electrode finger 21 as a whole exhibits a negative frequency temperature characteristic; the frequency of the electrode finger 21 decreases as the temperature increases and increases as the temperature decreases. It is not required that all parts of the electrode finger be made of a negative frequency temperature characteristic material. For example, the materials of the first electrode layer 211 and the second electrode layer 212, which constitute the main parts of the electrode finger, are negative frequency temperature characteristic materials, but the material of the connecting part between the first electrode layer 211 and the second electrode layer 212 may include, but is not limited to, a negative frequency temperature characteristic material, or it may be a material that does not change with temperature.

[0029] The resonator proposed in this application firstly reduces the resistance of the electrode finger 21 by setting the electrode finger 21 as a multilayer thickened electrode structure including at least a first electrode layer 211 and a second electrode layer 212, thereby reducing insertion loss and improving power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode finger 21 can be optimized by combining different materials.

[0030] Secondly, by setting the electrode mass M per unit length of electrode finger 21 along the aperture direction Y to be greater than 250λ 2 The large mass electrode finger 21 formed in this way can reduce the sound velocity of the resonator. This allows a smaller pitch (the distance between two adjacent electrode fingers 21) to be used to construct a resonator with the same function, thereby reducing the area of ​​the resonator and realizing the miniaturization of the resonator.

[0031] Furthermore, by setting an optimization layer 30 to cover the electrode finger 21, the material of the optimization layer 30 is a positive frequency temperature characteristic material with the opposite properties to the material of the electrode finger 21, and the thickness of the optimization layer 30 is greater than or equal to 50nm. In this way, the optimization layer 30 can compensate for the frequency temperature coefficient of the electrode finger 21, which can solve the problem that the overall frequency temperature coefficient (TCF) of the resonator is greatly reduced due to the increased mass of the electrode finger 21, causing the frequency of the resonator to change significantly with temperature, that is, the temperature characteristics deteriorate.

[0032] It should be noted that the resonator proposed in this embodiment achieves this by defining a multi-layered thickened electrode structure in which the electrode finger 21 includes at least a first electrode layer 211 and a second electrode layer 212, and setting the electrode mass M per unit length of the electrode finger 21 along the aperture direction Y to be greater than 250λ. 2 By combining several technical features, such as "the thickness of the optimized layer 30 is set to be greater than or equal to 50nm" and "the material of the electrode finger 21 is a negative frequency temperature characteristic material, and the material of the optimized layer 30 is a positive frequency temperature characteristic material", the problem of large size of existing resonators and the derivative problem of deterioration of resonator temperature characteristics are solved. This makes the finished resonator have the advantages of low insertion loss, high power tolerance, high reliability, good electrical performance, small size, frequency stability and high temperature adaptability, thus greatly expanding the application range of resonators.

[0033] In some embodiments, when the resonator is configured to operate in the B1 frequency band, the spacing between two adjacent electrode fingers 21 of the interdigital transducer 20 corresponding to the B1 frequency band is [0.6µm, 0.9µm]. Optionally, the spacing between two adjacent electrode fingers 21 of the interdigital transducer 20 corresponding to the B1 frequency band is any one of 0.6µm, 0.7µm, 0.8µm, 0.9µm, or any value between two adjacent fingers.

[0034] Optionally, in one embodiment, the transmission frequency of the B1 band is 1920MHz~1980MHz, and the reception frequency of the B1 band is 2110MHz~2170MHz.

[0035] It should be noted that in conventional resonators, the spacing between two adjacent electrode fingers 21 of the interdigital transducer 20 corresponding to the B1 frequency band is [0.9um, 1um]. The resonator proposed in this application, by setting large-mass electrode fingers 21, allows the spacing between two adjacent electrode fingers 21 of the interdigital transducer 20 corresponding to the B1 frequency band to be set to [0.6um, 0.9um]. That is, the pitch value of the resonator in this application is reduced by 10% to 40% compared to the pitch value (spacing between two adjacent electrode fingers 21) of conventional resonators.

[0036] In some embodiments, the absolute values ​​of the frequency temperature coefficients of the resonant frequency (Fr) and / or the anti-resonant frequency (Fa) are less than 25 ppm / °C. That is, for every 1 degree Celsius change in temperature, the output frequency of the resonator changes by no more than 25%. In other words, the resonator proposed in this application embodiment, by setting the electrode mass M per unit length along the aperture direction Y of the electrode finger 21 to be greater than 250λ... 2"The thickness of the optimization layer 30 is greater than or equal to 50nm", "The material of the electrode finger 21 is a negative frequency temperature characteristic material, and the material of the optimization layer 30 is a positive frequency temperature characteristic material". In a specific embodiment, the absolute value of the frequency temperature coefficient of the resonant frequency (Fr) and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency (Fa) can be less than 25ppm / ℃. That is, the frequency of the resonator can be controlled to be less than 25% of the output frequency of the resonator for every 1 degree Celsius change in temperature. The frequency stability and temperature adaptability of the resonator are better.

[0037] It should be noted that the absolute values ​​of the frequency temperature coefficient of the resonant frequency (Fr) and / or the absolute values ​​of the frequency temperature coefficient of the anti-resonant frequency (Fa) are not limited to less than 25 ppm / ℃. For example, in some other embodiments, by adjusting the materials of the electrode fingers and the optimization layer, and the thickness of the optimization layer, the absolute values ​​of the frequency temperature coefficient of the resonant frequency (Fr) and / or the absolute values ​​of the frequency temperature coefficient of the anti-resonant frequency (Fa) may also be less than any one of 15 ppm / ℃, 16 ppm / ℃, 17 ppm / ℃, 18 ppm / ℃, 19 ppm / ℃, 20 ppm / ℃, 21 ppm / ℃, 22 ppm / ℃, 23 ppm / ℃, 24 ppm / ℃, or any value between two adjacent values, so that the resonator has better frequency stability and higher temperature adaptability. The specific value can be determined according to the actual design requirements.

[0038] In some embodiments, the thickness of the optimization layer 30 ranges from [50nm, 150nm]. Further, in some embodiments, the thickness of the optimization layer 30 ranges from [70nm, 110nm]. Optionally, the thickness of the optimization layer 30 can be any one of 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, 145nm, and 150nm, or any value between two adjacent values. In this embodiment, by controlling the thickness of the optimization layer 30 to the aforementioned range, while satisfying the temperature compensation requirement for the electrode finger 21, the excessive thickness of the optimization layer 30 can be avoided from negatively impacting the resonator's performance. For example, in some embodiments, the optimization layer 30 can also regulate the resonator's frequency; if the optimization layer 30 is too thick, it is detrimental to the resonator's frequency control. Furthermore, it should be noted that the compensation of the frequency temperature coefficient of the electrode finger 21 by the optimization layer 30 has an edge effect. That is, within a certain thickness range, the optimization layer 30 has a good compensation effect on the frequency temperature coefficient of the electrode finger 21. Beyond this range, the optimization layer 30 is far away from the electrode finger 21, and the compensation effect on the frequency temperature coefficient of the electrode finger 21 is poor. Simulation results show that by controlling the thickness of the optimization layer 30 to be less than 150nm, the aforementioned edge effect can be avoided.

[0039] like Figure 1 and Figure 3 As shown, in some embodiments, the thickness of the optimization layer 30 is W, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M, satisfying the following relationship: (m), , , in, It is the density of the first electrode layer 211. It is the density of the second electrode layer 212. The height of the first electrode layer 211 along the direction perpendicular to the piezoelectric substrate 10. L is the height of the second electrode layer 212 along the direction perpendicular to the piezoelectric substrate 10, and L is the width of the bottom surface of the first electrode layer 211 along the first direction X. The first included angle is the angle formed by the bottom surface of the first electrode layer 211 and any side surface of the first electrode layer 211 along the aperture direction Y. The second included angle is the angle formed by the bottom surface of the second electrode layer 212 and any side surface of the second electrode layer 212 along the aperture direction Y. λ is the period length of the interdigital transducer 20, DF is the duty cycle of the electrode finger 21, the aperture direction Y is the extension direction of the electrode finger 21, and the first direction X is the arrangement direction of the multiple electrode fingers 21.

[0040] In this embodiment, the thickness W of the optimization layer 30 is set to satisfy a relationship with the electrode mass M per unit length of the electrode finger 21 along the aperture direction Y. (m), that is, the thickness of the optimization layer 30 varies with the change of the electrode mass M per unit length along the aperture direction Y of the electrode finger 21. In this embodiment, under the condition that the optimization layer 30 compensates for the frequency temperature coefficient of the electrode finger 21, the thickness of the optimization layer 30 is adapted to the electrode mass M per unit length along the aperture direction Y of the electrode finger 21, which can avoid the excessive thickness of the optimization layer 30 from affecting the frequency and thickness of the resonator.

[0041] In some embodiments, the duty cycle DF of electrode finger 21 ranges from [0.3, 0.7]. Optionally, in some embodiments, the duty cycle DF of electrode finger 21 is any one of 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, or any value between two adjacent values. In this embodiment, by setting the duty cycle DF of electrode finger 21 to the range of [0.3, 0.7], it is possible to optimize the electromechanical coupling coefficient to achieve the best bandwidth, suppress heterogeneous modes, reduce sensitivity to manufacturing process errors, and improve product yield.

[0042] In some embodiments, the electrode mass M per unit length of electrode finger 21 along the aperture direction Y ranges from [250λ]. 2 ,1000λ 2 Optionally, the electrode mass M per unit length along the aperture direction Y of electrode finger 21 is 250λ. 2 300λ 2 400λ 2 500λ 2 600λ 2 700λ 2 800λ 2 900λ 2 1000λ 2 Any one of the values ​​or any value between two adjacent values. In this embodiment, the range of the electrode mass M per unit length along the aperture direction Y of the electrode finger 21 is set to [250λ]. 2 ,1000λ 2While satisfying the aforementioned requirement for a large-mass electrode finger 21, it avoids the problem of excessive mass in the electrode finger 21 leading to waveguide mode (spurious mode) enhancement and a decrease in the quality factor Q of the resonator. Simulation experiments show that when the electrode mass M per unit length along the aperture direction Y of the electrode finger 21 is greater than 1000λ... 2 When this happens, the energy leaked from electrode 21 into the piezoelectric substrate increases, waveguide modes (hybrid modes) are enhanced, the quality factor Q decreases, and the resonator's performance is affected.

[0043] In some embodiments, the material of the first electrode layer 211 is a negative frequency temperature characteristic material, and the material of the second electrode layer 212 is a negative frequency temperature characteristic material.

[0044] In some embodiments, the material of the optimized layer 30 includes at least one of silicon nitride, aluminum oxide, silicon oxide, and silicon dioxide.

[0045] In some embodiments, the material of the first electrode layer 211 includes copper, the material of the second electrode layer 212 includes aluminum, and the thickness of the optimized layer 30 ranges from [77 nm to 150 nm]. In this embodiment, by setting the material of the first electrode layer 211 to include copper, the material of the second electrode layer 212 to include aluminum, and the thickness of the optimized layer 30 to be 77 nm or more and 150 nm or less, combined with the aforementioned "electrode mass M per unit length along the aperture direction Y of the electrode finger 21 is greater than 250λ", 2 The large-mass electrode can better control the frequency temperature coefficient of the resonator, giving the resonator the advantages of better frequency stability and temperature adaptability.

[0046] Optionally, the thickness of the optimized layer 30 is any one of 77nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, and 150nm, or any value between two adjacent values.

[0047] For example, such as Figure 4 As shown, in a specific embodiment, the material of the first electrode layer 211 includes copper, and the material of the second electrode layer 212 includes aluminum. When the duty cycle DF of the electrode finger 21 is 0.5, the thickness of the first electrode layer 211 is 0.07 μm, the thickness of the second electrode layer 212 is 0.13 μm, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M = 366 x 1e-12 (kg / m), it is obtained through simulation experiments. At this time, if the thickness of the optimized layer 30 is greater than 77 nm, the absolute value of the frequency temperature coefficient of the resonant frequency and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency are both less than 25 ppm / ℃.

[0048] In some embodiments, the material of the first electrode layer 211 includes copper, the material of the second electrode layer 212 includes aluminum, and the thickness of the optimized layer 30 ranges from [100.8 nm to 150 nm]. Similarly, in this embodiment, by setting the material of the first electrode layer 211 to include copper, the material of the second electrode layer 212 to include aluminum, and the thickness of the optimized layer 30 to be greater than 100.8 nm and less than 150 nm, combined with the above-mentioned "electrode mass M per unit length along the aperture direction Y of the electrode finger 21 is greater than 250λ", 2 The large-mass electrode can better control the frequency temperature coefficient of the resonator, giving the resonator the advantages of better frequency stability and temperature adaptability.

[0049] Optionally, the thickness of the optimized layer 30 is any one of 100.8nm, 110nm, 120nm, 130nm, 140nm, and 150nm, or any value between two adjacent ones.

[0050] For example, such as Figure 5 As shown, in one specific embodiment, the material of the first electrode layer 211 includes copper, and the material of the second electrode layer 212 includes aluminum. When the duty cycle DF of the electrode finger 21 is 0.5, the thickness of the first electrode layer 211 is 0.08 μm, the thickness of the second electrode layer 212 is 0.13 μm, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M = 398 x 1e-12 (kg / m), it is obtained through simulation experiments. At this time, if the thickness of the optimized layer 30 is greater than 100.8 nm, the absolute value of the frequency temperature coefficient of the resonant frequency of the resonator and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency are both less than 25 ppm / ℃.

[0051] Optionally, the optimization layer 30 is also configured to protect and moisture-proof the surface of the electrode fingers 21.

[0052] In some embodiments, the material of the first electrode layer 211 includes any one or an alloy of at least two of aluminum, copper, platinum, silver, gold, molybdenum, and tungsten. Further, in one embodiment, the material of the first electrode layer 211 includes any one or an alloy of at least two of copper, platinum, silver, and gold. In this embodiment, copper, platinum, silver, and gold are all heavy metals with high density. By using these materials for the first electrode layer 211, the propagation speed of the acoustic signal in the first electrode layer 211 can be reduced, which is beneficial for reducing the propagation speed of the acoustic signal in the interdigital transducer 20. In other words, with a fixed signal frequency, the wavelength of the sound wave can be reduced, thereby reducing the size of the interdigital transducer 20. Furthermore, copper, platinum, silver, and gold have high electromechanical coupling coefficients and low resistance, which is beneficial for the interdigital transducer 20 to have good performance.

[0053] In some embodiments, the material of the second electrode layer 212 includes aluminum or an aluminum alloy. In this embodiment, the second electrode layer 212 has good conductivity, which optimizes the conductivity of the electrode fingers 21. Furthermore, aluminum or aluminum alloys are less expensive, which helps reduce the cost of the resonator.

[0054] For example, in one embodiment, the first electrode layer 211 is made of platinum, the second electrode layer 212 is made of aluminum, and the electrode fingers 21 form a platinum-aluminum composite multilayer electrode. In another embodiment, the first electrode layer 211 is made of copper, the second electrode layer 212 is made of aluminum, and the electrode fingers 21 form a copper-aluminum composite multilayer electrode.

[0055] In some embodiments, the density of the first electrode layer 211 is greater than the density of the second electrode layer 212. In this embodiment, by placing the denser first electrode layer 211 closer to the piezoelectric substrate 10 than the less dense second electrode layer 212, the centroid height of the electrode fingers 21 can be reduced. Reducing the centroid height of the electrode fingers 21 can reduce the mechanical disturbance of the electrode fingers 21 to the piezoelectric substrate 10, which helps to better confine the acoustic wave energy near the surface of the piezoelectric substrate 10, suppress the excitation of bulk acoustic waves, thereby reducing transmission loss and improving the resonator quality factor Q.

[0056] In some embodiments, the density of the first electrode layer 211 is greater than or equal to 8000 kg / m3, and the density of the second electrode layer 212 is less than or equal to 4000 kg / m3.

[0057] In some embodiments, the thickness of the first electrode layer 211 in the direction perpendicular to the piezoelectric substrate 10 is [70nm, 100nm]. Optionally, the thickness of the first electrode layer 211 in the direction perpendicular to the piezoelectric substrate 10 is any one of 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, and 100nm, or any value between two adjacent values.

[0058] In some embodiments, the thickness of the second electrode layer 212 in the direction perpendicular to the piezoelectric substrate 10 is [70nm, 100nm]. Optionally, the thickness of the second electrode layer 212 in the direction perpendicular to the piezoelectric substrate 10 is any one of 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, and 100nm, or any value between two adjacent values.

[0059] like Figure 3As shown, in some embodiments, the bottom surface of the first electrode layer 211 forms a first angle θ1 with any side surface of the first electrode layer 211 along the aperture direction Y, and the bottom surface of the second electrode layer 212 forms a second angle θ2 with any side surface of the second electrode layer 212 along the aperture direction Y. The range of the first angle θ1 and the second angle θ2 is [70°, 85°]. The aperture direction Y is the extension direction of the electrode finger 21. Any side surface includes a first side surface S1 and a second side surface S2, and the first side surface S1 and the second side surface S2 are opposite to each other.

[0060] Optionally, the first included angle θ1 is any one of 70°, 75°, 80°, and 85°, or any value between two adjacent angles. Optionally, the second included angle θ2 is any one of 70°, 75°, 80°, and 85°, or any value between two adjacent angles.

[0061] It should be noted that in this application, the electrode finger 21 is a thickened electrode comprising a first electrode layer 211 and a second electrode layer 212. Firstly, by setting the first included angle θ1 and the second included angle θ2 to the aforementioned range, the problem of significant mass changes in the electrode finger 21 when the first included angle θ1 and the second included angle θ2 are adjusted to smaller angles, making it difficult to compensate for these changes by adjusting the duty cycle and film thickness of the electrode finger 21, can be avoided. Secondly, from a manufacturing perspective, setting the first included angle θ1 and the second included angle θ2 to the aforementioned range makes the manufacturing process easier to implement. Furthermore, by setting the first included angle θ1 and the second included angle θ2 to the aforementioned range, when the electrode finger 21 is closer to 90° within this range, its shape is more regular, resulting in less sound wave scattering within this angle range and fewer stray modes. This reduces the adverse effects of stray modes on the resonator and prevents energy leakage.

[0062] like Figure 2 As shown, in some embodiments, the electrode finger 21 further includes a first transition layer 213, a second transition layer 214, and a third transition layer 215. The first transition layer 213 is disposed on the piezoelectric substrate 10, the first electrode layer 211 is disposed on the first transition layer 213, the second transition layer 214 is disposed on the first electrode layer 211, the second electrode layer 212 is disposed on the second transition layer 214, and the third transition layer 215 is disposed on the second electrode layer 212. The first transition layer 213 reliably connects the piezoelectric substrate 10 to the first electrode layer 211, the second transition layer 214 reliably connects the first electrode layer 211 to the second electrode layer 212, thereby improving the overall mechanical strength and power characteristics of the interdigital transducer 20. The third transition layer 215 makes the contact or connection between the second electrode layer 212 and its surroundings tighter and more reliable, further increasing the overall mechanical strength and power characteristics of the electrode finger 21.

[0063] In some embodiments, at least one of the first transition layer 213, the second transition layer 214, and the third transition layer 215 has a thickness of less than 30 nm in the direction perpendicular to the piezoelectric substrate 10. With this embodiment, material usage can be reduced, costs lowered, weight reduced, and the height of the interdigital transducer 20 in the direction perpendicular to the piezoelectric substrate 10 decreased while ensuring reliable connection between the two components contacted or connected by the transition layers.

[0064] In some embodiments, the materials of the first transition layer 213, the second transition layer 214, and the third transition layer 215 all include any one or an alloy of at least two of titanium, chromium, copper, magnesium, and nickel.

[0065] like Figure 1 As shown, in some embodiments, the interdigital transducer 20 includes a first busbar 22, a second busbar 23, a plurality of first electrode fingers 21a, and a plurality of second electrode fingers 21b. The first busbar 22 and the second busbar 23 extend along a first direction X and are spaced apart in a second direction Y, wherein the first direction X is perpendicular to the second direction Y. One end of the first electrode finger 21a is connected to the first busbar 22, and the other end of the first electrode finger 21a extends toward the second busbar 23 and is spaced apart from the second busbar 23. One end of the second electrode finger 21b is connected to the second busbar 23, and the other end of the second electrode finger 21b extends toward the first busbar 22 and is spaced apart from the first busbar 22. The plurality of first electrode fingers 21a and the plurality of second electrode fingers 21b are staggered in the first direction X.

[0066] like Figure 1 As shown, in some embodiments, the resonator further includes a first reflective grating 40 and a second reflective grating 50. The first reflective grating 40, the interdigital transducer 20, and the second reflective grating 50 are arranged along a first direction X, that is, the first reflective grating 40 is located on the side of the interdigital transducer 20 away from the second reflective grating 50. The second reflective grating 50 is located on the side of the interdigital transducer 20 away from the first reflective grating 40. The first reflective grating 40 and the second reflective grating 50 are used to constrain the propagation range of the sound waves generated when the interdigital transducer 20 is working, thereby improving the performance of the interdigital transducer 20, and thus improving the performance of the resonator.

[0067] like Figure 2 As shown, in some embodiments, the piezoelectric substrate 10 includes a substrate layer 11, a piezoelectric layer 12, and a temperature compensation layer 13. The piezoelectric layer 12 and the temperature compensation layer are disposed on one side of the substrate layer 11, and the temperature compensation layer 13 is disposed between the substrate layer 11 and the piezoelectric layer 12. The first electrode layer 211 is disposed on the side of the piezoelectric layer 12 away from the temperature compensation layer 13. The temperature compensation layer 13 can compensate for the frequency temperature coefficient of the piezoelectric layer 12, resulting in a lower frequency temperature coefficient of the shaped resonator and reducing the impact of temperature changes on the resonator's performance.

[0068] In some embodiments, the thickness of the piezoelectric layer 12 is in the range of [0.12λ, 0.2λ]. Optionally, the thickness of the piezoelectric layer 12 is any one of 0.12λ, 0.13λ, 0.14λ, 0.15λ, 0.16λ, 0.17λ, 0.18λ, 0.19λ, 0.20λ, or any value between two adjacent values.

[0069] It should be noted that, for conventional resonators, such as those operating in the B1 band, the thickness of the piezoelectric layer 12 ranges from [0.2λ, 0.35λ]. After the above-mentioned improvements, the thickness of the piezoelectric layer 12 in the resonator proposed in this application can be set to [0.12λ, 0.2λ], which means that the thickness of the piezoelectric layer 12 is reduced by about 40% to 50% compared to that of conventional resonators.

[0070] As described above, the resonator proposed in this application has a larger mass of electrode finger 21 compared to that of conventional resonators. This increased mass of electrode finger 21 leads to a higher coupling coefficient (KT-squared, KT...). 2 The coupling coefficient increases. In this embodiment, by reducing the thickness of the piezoelectric layer 12, compensation can be achieved.

[0071] In some embodiments, the thickness of the piezoelectric layer 12 is less than or equal to 2 μm.

[0072] like Figure 2 As shown, in some embodiments, the thickness of the piezoelectric layer 12 along the direction perpendicular to the piezoelectric substrate 10 is j, and the thickness of the temperature compensation layer 13 along the direction perpendicular to the piezoelectric substrate 10 is k, where 0.75j < k < 1.25j, for example, k is any one of 0.8j, 1j, 1.2j, or any value between two adjacent values. In this embodiment, setting the thickness of the temperature compensation layer 13 along the direction perpendicular to the piezoelectric substrate 10 to the above-mentioned range satisfies both the need to compensate for the frequency temperature coefficient of the piezoelectric layer 12, reducing the impact of temperature changes on the resonator's performance, and the need to control the thickness of the temperature compensation layer 13 within a reasonable range, thereby controlling the overall thickness of the resonator.

[0073] In some embodiments, the longitudinal wave velocity of the substrate 11 is [4000 m / s, 10000 m / s]. Optionally, the longitudinal wave velocity of the substrate 11 can be set to any one of 4000 m / s, 4500 m / s, 5000 m / s, 6000 m / s, 7000 m / s, 8000 m / s, 9000 m / s, and 10000 m / s, or any value between two adjacent values. Here, the longitudinal wave of the substrate 11 refers to a wave in which the vibration direction of the sound wave is parallel to the propagation direction of the sound wave when it propagates in the corresponding film layer; the longitudinal wave velocity of the substrate 11 is the velocity corresponding to this wave. In this embodiment, by controlling the magnitude of the longitudinal wave velocity in the substrate 11, the high-frequency waveguide mode can be reduced, and the impact of the high-frequency waveguide mode caused by the waveguide mode on the resonator performance can be reduced.

[0074] In some embodiments, the longitudinal wave velocity of the substrate 11 is greater than that of the piezoelectric layer 12. In this embodiment, sound waves of a specific frequency can be confined within the piezoelectric layer 12 and the substrate 11. For example, sound waves with frequencies lower than the resonant frequency are easily confined within the piezoelectric layer 12 and the substrate 11, such as sound waves with frequencies less than 1.1 times the resonant frequency, thereby improving the Q value of the master mode.

[0075] In some embodiments, the longitudinal wave velocity in the piezoelectric layer 12 ranges from [6000 m / s to 7000 m / s]. Optionally, the longitudinal wave velocity in the piezoelectric layer 12 is any one of 6000 m / s, 6500 m / s, and 7000 m / s, or any value between two adjacent values.

[0076] In some embodiments, the material of the substrate layer 11 includes any one or at least two of quartz, silicon, gallium arsenide, indium phosphide, germanium, zinc oxide, germanium-silicon alloy, zinc selenide, gallium ions, and lithium tetraborate.

[0077] In some embodiments, the piezoelectric layer 12 comprises any one of quartz, aluminum nitride, sapphire, lithium niobate, and lithium tantalate.

[0078] In some embodiments, the material of the temperature compensation layer 13 includes one or more of silicon dioxide, silicon oxide, and silicon nitride.

[0079] In some embodiments, the piezoelectric substrate 10 further includes a functional layer 14 disposed between the temperature compensation layer 13 and the substrate layer 11, wherein the speed at which sound waves propagate on the functional layer 14 is greater than the speed at which they propagate on the piezoelectric layer 12 and the temperature compensation layer 13. In this embodiment, by providing the functional layer 14, and ensuring that the speed at which sound waves propagate on the functional layer 14 is greater than the speed at which they propagate on the piezoelectric layer 12 and the temperature compensation layer 13, the propagation speed of sound waves on the resonator can be increased.

[0080] In some embodiments, the material of the functional layer 14 includes at least one of diamond, aluminum nitride, silicon carbide, aluminum oxide, silicon, and silicon nitride.

[0081] like Figures 1 to 3 As shown, embodiments of this application also propose a resonator comprising a piezoelectric substrate 10, an interdigital transducer 20, and an optimization layer 30. The interdigital transducer 20 includes electrode fingers 21, each electrode finger comprising at least a first electrode layer 211 and a second electrode layer 212. The first electrode layer 211 is disposed on one side of the piezoelectric substrate 10, and the second electrode layer 212 is disposed on the side of the first electrode layer 211 away from the piezoelectric substrate 10. The optimization layer 30 is disposed on the side of the piezoelectric substrate 10 where the electrode fingers 21 are disposed and covers both the electrode fingers 21 and the piezoelectric substrate 10. The optimization layer 30 has a thickness of [50 nm, 150 nm] and is configured to compensate for the temperature coefficient of the electrode fingers 21, such that the absolute value of the temperature coefficient of the resonant frequency and / or the absolute value of the temperature coefficient of the anti-resonant frequency of the resonator is less than a preset value.

[0082] The resonator proposed in this embodiment firstly reduces the resistance of the electrode fingers 21 by setting them as a multi-layered, thickened electrode structure comprising at least a first electrode layer 211 and a second electrode layer 212. This reduces insertion loss and improves power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode fingers 21 can be optimized through combinations of different materials. Secondly, by covering the electrode fingers 21 with an optimization layer 30, the thickness of which is set to [50nm, 150nm], and the optimization layer 30 is configured to compensate for the frequency temperature coefficient of the electrode fingers 21, ensuring that the absolute value of the frequency temperature coefficient of the resonant frequency and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency are less than a preset value. This avoids significant frequency changes with temperature, preventing the deterioration of temperature characteristics. It should be noted that the resonator proposed in this embodiment combines several technical features, including "the electrode finger 21 includes at least a multi-layer thickened electrode structure of a first electrode layer 211 and a second electrode layer 212", "the thickness range of the optimized layer 30 is [50nm, 150nm]", and "the optimized layer 30 is configured to compensate for the temperature coefficient of the electrode finger 21 so that the absolute value of the frequency temperature coefficient of the resonant frequency and / or the absolute value of the frequency temperature coefficient of the anti-resonant frequency is less than a preset value". Under the combined effect of these technical features, the finished resonator simultaneously possesses the advantages of low insertion loss, high power tolerance, high reliability, good electrical performance, frequency stability, and high temperature adaptability, thereby significantly expanding the application range of the resonator.

[0083] In some embodiments, the preset value is 25 ppm / ℃.

[0084] In some embodiments, the thickness of the optimization layer 30 is [70nm, 110nm].

[0085] In some embodiments, the thickness of the optimization layer 30 is W, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M, satisfying the following relationship: (m), , , in, It is the density of the first electrode layer 211. It is the density of the second electrode layer 212. The height of the first electrode layer 211 along the direction perpendicular to the piezoelectric substrate 10. L is the height of the second electrode layer 212 along the direction perpendicular to the piezoelectric substrate 10, and L is the width of the bottom surface of the first electrode layer 211 along the first direction X. Let θ1 be the first included angle, which is the angle formed by the bottom surface of the first electrode layer 211 and any side surface of the first electrode layer 211 along the aperture direction Y. The second included angle θ2 is the angle formed by the bottom surface of the second electrode layer 212 and any side surface of the second electrode layer 212 along the aperture direction Y. λ is the period length of the interdigital transducer 20. DF is the duty cycle of the electrode finger 21. The aperture direction Y is the extension direction of the electrode finger 21. The first direction X is the arrangement direction of the multiple electrode fingers 21.

[0086] In some embodiments, electrode fingers 21 are made of a material with a negative temperature coefficient, and optimization layer 30 is made of a material with a positive temperature coefficient.

[0087] In some embodiments, the material of the first electrode layer 211 includes copper, the material of the second electrode layer 212 includes aluminum, and the thickness of the optimized layer 30 ranges from [77nm, 150nm].

[0088] In some embodiments, the duty cycle DF of the electrode finger 21 is 0.5, the thickness of the first electrode layer 211 is 0.07 μm, the thickness of the second electrode layer 212 is 0.13 μm, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M = 366 x 1e-12 (kg / m).

[0089] In some embodiments, the first electrode layer 211 is made of copper, the second electrode layer 212 is made of aluminum, and the thickness of the optimized layer 30 is in the range of [100.8 nm, 150 nm].

[0090] In some embodiments, the duty cycle DF of the electrode finger 21 is 0.5, the thickness of the first electrode layer 211 is 0.08 μm, the thickness of the second electrode layer 212 is 0.13 μm, and the electrode mass per unit length of the electrode finger 21 along the aperture direction Y is M = 398 x 1e-12 (kg / m).

[0091] In some embodiments, the thickness of the first electrode layer 211 in the direction perpendicular to the piezoelectric substrate 10 is [70nm, 100nm].

[0092] In some embodiments, the thickness of the second electrode layer 212 in the direction perpendicular to the piezoelectric substrate 10 is [70nm, 100nm].

[0093] The structure, connection relationship, extended description, value range and beneficial effects of other components of the resonator proposed in this embodiment can be described above and will not be repeated here.

[0094] like Figures 1 to 3 As shown, embodiments of this application also propose a resonator, which includes a piezoelectric substrate 10, an interdigital transducer 20, and an optimization layer 30. The interdigital transducer 20 includes electrode fingers 21, each electrode finger including at least a first electrode layer 211 and a second electrode layer 212. The first electrode layer 211 is disposed on one side of the piezoelectric substrate 10, and the second electrode layer 212 is disposed on the side of the first electrode layer 211 away from the piezoelectric substrate 10. The optimization layer 30 is disposed on the side of the piezoelectric substrate 10 where the electrode fingers 21 are disposed and covers the electrode fingers 21 and the piezoelectric substrate 10. The thickness of the optimization layer 30 is W, and the electrode mass per unit length of the electrode fingers 21 along the aperture direction Y is M, satisfying the following relationship: (m), , , in, It is the density of the first electrode layer 211. It is the density of the second electrode layer 212. The height of the first electrode layer 211 along the direction perpendicular to the piezoelectric substrate 10. L is the height of the second electrode layer 212 along the direction perpendicular to the piezoelectric substrate 10, and L is the width of the bottom surface of the first electrode layer 211 along the first direction X. Let θ1 be the first included angle, which is the angle formed by the bottom surface of the first electrode layer 211 and any side surface of the first electrode layer 211 along the aperture direction Y. The second included angle θ2 is the angle formed by the bottom surface of the second electrode layer 212 and any side surface of the second electrode layer 212 along the aperture direction Y. λ is the period length of the interdigital transducer 20. DF is the duty cycle of the electrode finger 21. The aperture direction Y is the extension direction of the electrode finger 21. The first direction X is the arrangement direction of the multiple electrode fingers 21.

[0095] The resonator proposed in this embodiment firstly reduces the resistance of the electrode finger 21 by setting it as a multi-layered thickened electrode structure including at least a first electrode layer 211 and a second electrode layer 212, thereby reducing insertion loss and improving power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode finger 21 can be optimized through combinations of different materials. Secondly, the thickness W of the optimization layer 30 is set to satisfy a relationship with the electrode mass M per unit length along the aperture direction Y of the electrode finger 21. (m), that is, the thickness of the optimization layer 30 varies with the change of the electrode mass M per unit length along the aperture direction Y of the electrode finger 21. In this embodiment, when the optimization layer 30 is configured to compensate for the frequency temperature coefficient of the electrode finger 21, under the condition that the optimization layer 30 compensates for the frequency temperature coefficient of the electrode finger 21, the excessive thickness of the optimization layer 30 can be avoided from affecting the frequency and thickness of the resonator.

[0096] In some embodiments, the duty cycle DF of the electrode finger 21 ranges from [0.3, 0.7]; the electrode mass M per unit length of the electrode finger 21 along the aperture direction Y ranges from [250λ]. 2 ,1000λ 2 ].

[0097] In some embodiments, the thickness of the optimized layer 30 ranges from [50 nm to 150 nm].

[0098] In some embodiments, the thickness of the optimized layer 30 ranges from [70 nm to 110 nm].

[0099] In some embodiments, the material of electrode finger 21 is a negative frequency temperature characteristic material, and the material of optimization layer 30 is a positive frequency temperature characteristic material.

[0100] The structure, connection relationship, extended description, value range and beneficial effects of other components of the resonator proposed in this embodiment can be described above and will not be repeated here.

[0101] like Figures 1 to 3As shown, embodiments of this application also propose a resonator, which includes a piezoelectric substrate 10, an interdigital transducer 20, and an optimization layer 30. The piezoelectric substrate 10 includes a substrate layer 11, a piezoelectric layer 12, and a temperature compensation layer 13. The piezoelectric layer 12 and the temperature compensation layer 13 are disposed on one side of the substrate layer 11, and the temperature compensation layer 13 is disposed between the substrate layer 11 and the piezoelectric layer 12. The interdigital transducer 20 includes electrode fingers 21, each electrode finger including at least a first electrode layer 211 and a second electrode layer 212. The first electrode layer 211 is disposed on the side of the piezoelectric layer 12 away from the temperature compensation layer 13, and the second electrode layer 212 is disposed on the side of the first electrode layer 211 away from the piezoelectric layer 12. The optimization layer 30 is disposed on the side of the piezoelectric layer 12 where the electrode fingers 21 are disposed, and covers the electrode fingers 21 and the piezoelectric layer 12. The electrode mass M per unit length of the electrode fingers 21 along the aperture direction Y is greater than 250λ. 2 The aperture direction Y is the extension direction of the electrode finger 21, λ is the period length of the interdigital transducer 20, and the thickness of the optimization layer 30 is greater than or equal to 50 nm.

[0102] The resonator proposed in this embodiment firstly reduces the resistance of the electrode finger 21 by setting it as a multi-layered thickened electrode structure including at least a first electrode layer 211 and a second electrode layer 212, thereby reducing insertion loss and improving power tolerance and reliability. Without sacrificing mechanical stability, the electrical performance of the electrode finger 21 can be optimized through combinations of different materials. Secondly, by setting the electrode mass M per unit length of the electrode finger 21 along the aperture direction Y to be greater than 250λ, the resonator achieves this. 2 The resulting large-mass electrode finger 21 reduces the sound velocity of the resonator, allowing for the use of a smaller pitch (the distance between two adjacent electrode fingers 21) to construct a resonator with the same function, thereby reducing the resonator area and achieving miniaturization. Secondly, by setting the thickness of the optimization layer 30 to be greater than or equal to 50 nm, when one of the electrode fingers 21 and the optimization layer 30 is made of a material with negative frequency temperature characteristics, and the other is made of a material with positive frequency temperature characteristics, this thickness of the optimization layer 30 can compensate for the frequency temperature coefficient of the electrode finger 21. This solves the problem that the increased mass of the electrode finger 21 leads to a significant decrease in the overall temperature coefficient of frequency (TCF) of the resonator, causing the resonator's frequency to change drastically with temperature, i.e., a deterioration in temperature characteristics.

[0103] It should be noted that the resonator proposed in this embodiment achieves this by defining a multi-layered thickened electrode structure in which the electrode finger 21 includes at least a first electrode layer 211 and a second electrode layer 212, and setting the electrode mass M per unit length of the electrode finger 21 along the aperture direction Y to be greater than 250λ.2 By combining several technical features, such as "setting the thickness of the optimized layer 30 to be greater than or equal to 50nm", the problem of large size of existing resonators and the resulting problem of deterioration of temperature characteristics of resonators are solved. This allows the finished resonator to have the advantages of low insertion loss, high power tolerance, high reliability, good electrical performance, small size, frequency stability and high temperature adaptability, thereby greatly expanding the application range of resonators.

[0104] In some embodiments, the thickness of the optimized layer 30 ranges from [50 nm to 150 nm].

[0105] In some embodiments, the thickness of the optimized layer 30 ranges from [75nm, 110nm].

[0106] In some embodiments, the material of electrode finger 21 is a negative frequency temperature characteristic material, and the material of optimization layer 30 is a positive frequency temperature characteristic material.

[0107] In some embodiments, the piezoelectric substrate 10 further includes a functional layer 14 disposed between the temperature compensation layer 13 and the substrate layer 11, wherein the speed at which sound waves propagate on the functional layer 14 is greater than the speed at which sound waves propagate on the piezoelectric layer 12 and the temperature compensation layer 13.

[0108] The structure, connection relationship, extended description, value range and beneficial effects of other components of the resonator proposed in this embodiment can be described above and will not be repeated here.

[0109] Embodiments of this application also propose a radio frequency module that includes the resonator described above.

[0110] The radio frequency module proposed in this embodiment has the following advantages because it includes the above-mentioned resonator: it can achieve miniaturization and can solve the problem that the temperature coefficient of frequency (TCF) of the resonator is greatly reduced due to the increased mass of the electrode finger 21, which causes the temperature characteristics of the resonator to deteriorate.

[0111] The structure, connection relationship, extended description, value range and beneficial effects of other components of the radio frequency module proposed in this embodiment can be described above and will not be repeated here.

[0112] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "mechanical coupling," and "coupling" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and can refer to the internal communication of two components or the interaction between two components. Mechanical coupling or coupling of two components includes direct coupling and indirect coupling, such as a direct fixed connection or a connection through a transmission mechanism. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0113] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0114] The foregoing disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0115] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific method step, feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific method steps, features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0116] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A resonator, characterized in that, include: piezoelectric substrate; An interdigital transducer includes electrode fingers, each electrode finger comprising at least a first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on one side of the piezoelectric substrate, and the second electrode layer is disposed on the side of the first electrode layer away from the piezoelectric substrate. An optimization layer is disposed on the side of the piezoelectric substrate where the electrode fingers are located, and covers the electrode fingers and the piezoelectric substrate, wherein the electrode mass M per unit length of the electrode fingers along the aperture direction is greater than 250λ. 2 The aperture direction is the extension direction of the electrode fingers, λ is the period length of the interdigital transducer, the thickness of the optimization layer is greater than or equal to 50 nm, the material of the electrode fingers is a negative frequency temperature characteristic material, and the material of the optimization layer is a positive frequency temperature characteristic material.

2. The resonator as described in claim 1, characterized in that, When the resonator is configured to operate in the B1 frequency band, the spacing between two adjacent electrode fingers of the interdigital transducer corresponding to the B1 frequency band is [0.6um, 0.9um].

3. The resonator as described in claim 1, characterized in that, The absolute value of the temperature coefficient of the resonant frequency and / or the absolute value of the temperature coefficient of the anti-resonant frequency of the resonator is less than 25 ppm / ℃.

4. The resonator as described in claim 1, characterized in that, The thickness range of the optimized layer is [50nm, 150nm].

5. The resonator as described in claim 1, characterized in that, The thickness of the optimized layer ranges from [75nm to 110nm].

6. The resonator as claimed in claim 1, characterized in that, The thickness of the optimized layer is W, and the mass per unit length of the electrode finger along the aperture direction is M, satisfying the following relationship: （m）， ， ， in, It is the density of the first electrode layer. It is the density of the second electrode layer. The height of the first electrode layer along a direction perpendicular to the piezoelectric substrate. L is the height of the second electrode layer along the direction perpendicular to the piezoelectric substrate, and L is the width of the bottom surface of the first electrode layer along the first direction. The first included angle is the angle formed by the bottom surface of the first electrode layer and any side surface of the first electrode layer along the aperture direction. The second included angle is the angle formed by the bottom surface of the second electrode layer and any side surface of the second electrode layer along the aperture direction, λ is the period length of the interdigital transducer, DF is the duty cycle of the electrode finger, the aperture direction is the extension direction of the electrode finger, and the first direction is the arrangement direction of the plurality of electrode fingers.

7. The resonator as described in claim 6, characterized in that, The duty cycle DF of the electrode finger ranges from [0.3, 0.7]; the electrode mass M per unit length along the aperture direction ranges from [250λ]. 2 ,1000λ 2 ].

8. The resonator as claimed in claim 1, characterized in that, The material of the first electrode layer is a negative frequency temperature characteristic material, and the material of the second electrode layer is a negative frequency temperature characteristic material.

9. The resonator as claimed in claim 1, characterized in that, The material of the first electrode layer includes any one or an alloy of at least two of aluminum, copper, platinum, silver, gold, molybdenum, and tungsten, and the material of the second electrode layer includes aluminum or an aluminum alloy.

10. The resonator as claimed in claim 1, characterized in that, The material of the optimized layer includes at least one of silicon nitride, aluminum oxide, silicon oxide, and silicon dioxide.

11. The resonator as claimed in claim 1, characterized in that, The material of the first electrode layer includes copper, the material of the second electrode layer includes aluminum, and the thickness of the optimized layer ranges from [77nm, 150nm].

12. The resonator as claimed in claim 11, characterized in that, The duty cycle DF of the electrode finger is 0.5, the thickness of the first electrode layer is 0.07 μm, the thickness of the second electrode layer is 0.13 μm, and the electrode mass per unit length along the aperture direction of the electrode finger is M = 366 x 1e-12 (kg / m).

13. The resonator as claimed in claim 1, characterized in that, The material of the first electrode layer includes copper, the material of the second electrode layer includes aluminum, and the thickness of the optimized layer ranges from [100.8 nm to 150 nm].

14. The resonator as claimed in claim 13, characterized in that, The duty cycle DF of the electrode finger is 0.5, the thickness of the first electrode layer is 0.08 μm, the thickness of the second electrode layer is 0.13 μm, and the electrode mass per unit length along the aperture direction of the electrode finger is M = 398 x 1e-12 (kg / m).

15. The resonator as claimed in claim 1, characterized in that, The density of the first electrode layer is greater than the density of the second electrode layer.

16. The resonator as claimed in claim 1, characterized in that, The density of the first electrode layer is greater than or equal to 8000 kg / m3, and the density of the second electrode layer is less than or equal to 4000 kg / m3.

17. The resonator as claimed in claim 1, characterized in that, The thickness of the first electrode layer in the direction perpendicular to the piezoelectric substrate is [70nm, 100nm]; and / or, The thickness of the second electrode layer in the direction perpendicular to the piezoelectric substrate is [70nm, 100nm].

18. The resonator as claimed in claim 1, characterized in that, The bottom surface of the first electrode layer forms a first angle with any side surface of the first electrode layer along the aperture direction, and the bottom surface of the second electrode layer forms a second angle with any side surface of the second electrode layer along the aperture direction. The range of the first angle and the second angle is [70°, 85°]. The aperture direction is the extension direction of the electrode finger. The any side surface includes a first side surface and a second side surface, and the first side surface and the second side surface are opposite to each other.

19. The resonator as claimed in claim 1, characterized in that, The electrode further includes a first transition layer, a second transition layer, and a third transition layer. The first transition layer is disposed on the piezoelectric substrate, the first electrode layer is disposed on the first transition layer, the second transition layer is disposed on the first electrode layer, the second electrode layer is disposed on the second transition layer, and the third transition layer is disposed on the second electrode layer.

20. The resonator as claimed in claim 19, characterized in that, At least one of the first transition layer, the second transition layer, and the third transition layer has a thickness of less than 30 nm in the direction perpendicular to the piezoelectric substrate.

21. The resonator as claimed in claim 19, characterized in that, The materials of the first transition layer, the second transition layer and the third transition layer all include any one or an alloy of at least two of titanium, chromium, copper, magnesium and nickel.

22. The resonator as claimed in claim 1, characterized in that, The piezoelectric substrate includes a substrate layer, a piezoelectric layer, and a temperature compensation layer. The piezoelectric layer and the temperature compensation layer are disposed on one side of the substrate layer, and the temperature compensation layer is disposed between the substrate layer and the piezoelectric layer. The first electrode layer is disposed on the side of the piezoelectric layer away from the temperature compensation layer.

23. The resonator as claimed in claim 1, characterized in that, The thickness of the piezoelectric layer is in the range of [0.12λ, 0.2λ]; or the thickness of the piezoelectric layer is less than or equal to 2 μm.

24. The resonator as claimed in claim 22, characterized in that, The longitudinal wave velocity of the substrate is [4000m / s, 10000m / s].

25. The resonator as claimed in claim 22, characterized in that, The longitudinal wave velocity of the substrate is greater than that of the piezoelectric layer.

26. The resonator as claimed in claim 22, characterized in that, The longitudinal wave velocity in the piezoelectric layer ranges from 6000 m / s to 7000 m / s.

27. The resonator as claimed in claim 22, characterized in that, The substrate material includes any one or at least two of the following: quartz, silicon, gallium arsenide, indium phosphide, germanium, zinc oxide, germanium-silicon alloy, zinc selenide, gallium phosphate, and lithium tetraborate; and / or, The piezoelectric layer includes any one of quartz, aluminum nitride, sapphire, lithium niobate, and lithium tantalate.

28. The resonator as claimed in claim 22, characterized in that, The piezoelectric substrate further includes a functional layer disposed between the temperature compensation layer and the substrate layer, wherein the speed at which sound waves propagate on the functional layer is greater than the speed at which they propagate on the piezoelectric layer and the temperature compensation layer.

29. The resonator as claimed in claim 28, characterized in that, The material of the functional layer includes at least one of diamond, aluminum nitride, silicon carbide, aluminum oxide, silicon, and silicon nitride.

30. A resonator, characterized in that, include: piezoelectric substrate; An interdigital transducer includes electrode fingers, each electrode finger comprising at least a first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on one side of the piezoelectric substrate, and the second electrode layer is disposed on the side of the first electrode layer away from the piezoelectric substrate. An optimization layer is disposed on the side of the piezoelectric substrate where the electrode fingers are disposed and covers the electrode fingers and the piezoelectric substrate; The thickness of the optimization layer is [50nm, 150nm], and it is configured to compensate for the temperature coefficient of the electrode fingers so that the absolute value of the temperature coefficient of the resonant frequency and / or the absolute value of the temperature coefficient of the anti-resonant frequency of the resonator is less than a preset value.

31. The resonator as claimed in claim 30, characterized in that, The preset value is 25 ppm / ℃.

32. The resonator as claimed in claim 30, characterized in that, The thickness of the optimized layer is [70nm, 110nm].

33. The resonator as claimed in claim 30, characterized in that, The thickness of the optimized layer is W, and the mass per unit length of the electrode finger along the aperture direction is M, satisfying the following relationship: （m）， ， ， in, It is the density of the first electrode layer. It is the density of the second electrode layer. The height of the first electrode layer along a direction perpendicular to the piezoelectric substrate. L is the height of the second electrode layer along the direction perpendicular to the piezoelectric substrate, and L is the width of the bottom surface of the first electrode layer along the first direction. The first included angle is the angle formed by the bottom surface of the first electrode layer and any side surface of the first electrode layer along the aperture direction. The second included angle is the angle formed by the bottom surface of the second electrode layer and any side surface of the second electrode layer along the aperture direction, λ is the period length of the interdigital transducer, DF is the duty cycle of the electrode finger, the aperture direction is the extension direction of the electrode finger, and the first direction is the arrangement direction of the plurality of electrode fingers.

34. The resonator as claimed in claim 30, characterized in that, The electrode is made of a material with a negative temperature coefficient, and the optimization layer is made of a material with a positive temperature coefficient.

35. The resonator as claimed in claim 30, characterized in that, The material of the first electrode layer includes copper, the material of the second electrode layer includes aluminum, and the thickness of the optimized layer ranges from [77nm, 150nm].

36. The resonator as claimed in claim 35, characterized in that, The duty cycle DF of the electrode finger is 0.5, the thickness of the first electrode layer is 0.07 μm, the thickness of the second electrode layer is 0.13 μm, and the electrode mass per unit length along the aperture direction of the electrode finger is M = 366 x 1e-12 (kg / m).

37. The resonator as claimed in claim 30, characterized in that, The material of the first electrode layer includes copper, the material of the second electrode layer includes aluminum, and the thickness of the optimized layer ranges from [100.8 nm to 150 nm].

38. The resonator as claimed in claim 37, characterized in that, The duty cycle DF of the electrode finger is 0.5, the thickness of the first electrode layer is 0.08 μm, the thickness of the second electrode layer is 0.13 μm, and the electrode mass per unit length along the aperture direction of the electrode finger is M = 398 x 1e-12 (kg / m).

39. The resonator as claimed in claim 30, characterized in that, The thickness of the first electrode layer in the direction perpendicular to the piezoelectric substrate is [70nm, 100nm]; and / or, The thickness of the second electrode layer in the direction perpendicular to the piezoelectric substrate is [70nm, 100nm].

40. A resonator, characterized in that, include: piezoelectric substrate; An interdigital transducer includes electrode fingers, each electrode finger comprising at least a first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on one side of the piezoelectric substrate, and the second electrode layer is disposed on the side of the first electrode layer away from the piezoelectric substrate. An optimization layer is disposed on the side of the piezoelectric substrate where the electrode fingers are disposed and covers the electrode fingers and the piezoelectric substrate; The thickness of the optimized layer is W, and the mass per unit length of the electrode finger along the aperture direction is M, satisfying the following relationship: （m）， ， ， in, It is the density of the first electrode layer. It is the density of the second electrode layer. The height of the first electrode layer along a direction perpendicular to the piezoelectric substrate. L is the height of the second electrode layer along the direction perpendicular to the piezoelectric substrate, and L is the width of the bottom surface of the first electrode layer along the first direction. The first included angle is the angle formed by the bottom surface of the first electrode layer and any side surface of the first electrode layer along the aperture direction. The second included angle is the angle formed by the bottom surface of the second electrode layer and any side surface of the second electrode layer along the aperture direction, λ is the period length of the interdigital transducer, DF is the duty cycle of the electrode finger, the aperture direction is the extension direction of the electrode finger, and the first direction is the arrangement direction of the plurality of electrode fingers.

41. The resonator as claimed in claim 40, characterized in that, The duty cycle DF of the electrode finger ranges from [0.3, 0.7]; the electrode mass M per unit length along the aperture direction ranges from [250λ]. 2 ,1000λ 2 ].

42. The resonator as claimed in claim 40, characterized in that, The thickness range of the optimized layer is [50nm, 150nm].

43. The resonator as claimed in claim 40, characterized in that, The thickness range of the optimized layer is [70nm, 110nm].

44. The resonator as claimed in claim 40, characterized in that, The electrode is made of a material with negative frequency temperature characteristics, and the optimized layer is made of a material with positive frequency temperature characteristics.

45. A resonator, characterized in that, include: A piezoelectric substrate, comprising a substrate layer, a piezoelectric layer, and a temperature compensation layer, wherein the piezoelectric layer and the temperature compensation layer are disposed on one side of the substrate layer, and the temperature compensation layer is disposed between the substrate layer and the piezoelectric layer; An interdigital transducer includes electrode fingers, each electrode finger comprising at least a first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the piezoelectric layer away from the temperature compensation layer, and the second electrode layer is disposed on the side of the first electrode layer away from the piezoelectric layer. An optimization layer is disposed on the side of the piezoelectric layer where the electrode fingers are disposed, and covers the electrode fingers and the piezoelectric layer; Wherein, the electrode refers to an electrode with a unit length mass M greater than 250λ along the aperture direction. 2 The aperture direction is the extension direction of the electrode fingers, λ is the period length of the interdigital transducer, and the thickness of the optimization layer is greater than or equal to 50 nm.

46. ​​The resonator as claimed in claim 45, characterized in that, The thickness range of the optimized layer is [50nm, 150nm].

47. The resonator as claimed in claim 45, characterized in that, The thickness of the optimized layer ranges from [75nm to 110nm].

48. The resonator as claimed in claim 45, characterized in that, The electrode is made of a material with negative frequency temperature characteristics, and the optimized layer is made of a material with positive frequency temperature characteristics.

49. The resonator as claimed in claim 45, characterized in that, The piezoelectric substrate further includes a functional layer disposed between the temperature compensation layer and the substrate layer, wherein the speed at which sound waves propagate on the functional layer is greater than the speed at which they propagate on the piezoelectric layer and the temperature compensation layer.

50. A radio frequency module, characterized in that, Includes the resonator according to any one of claims 1 to 49.

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