Radio frequency filter and method for manufacturing a surface acoustic wave device - Patents.com

Abstract

To provide a surface acoustic wave (SAW) device that provides resonance for a surface acoustic wave having a wavelength λ.SOLUTION: A SAW device 100 with a mass-loaded electrode has a wavelength λ and includes a quartz substrate 112 and a piezoelectric layer 104 formed of LiTaO3 or LiNbO3 disposed on the quartz substrate. The piezoelectric layer has a thickness greater than 2λ. The surface acoustic wave device further includes an interdigital transducer electrode 102 formed on a first surface 110 of the piezoelectric layer, the interdigital transducer electrode having a mass density ρ in the range of 1.50 g / cm3<ρ≤6.00 g / cm3, 6.00 g / cm3<ρ≤12.0 g / cm3, or 12.0 g / cm3<ρ≤23.0 g / cm3, and a thickness greater than 0.148λ, 0.079λ, or 0.036λ, respectively.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on the application filed on September 16, 2019 entitled "Surface Acoustic Wave Device Having Mass-Loaded Electrodes" This application claims priority to U.S. Provisional Application No. 62 / 901,202, entitled "Comparative Patent Application No. 11 / 133,431," the entire disclosure of which is incorporated herein by reference in its entirety. The body is expressly incorporated herein by reference.

[0002] The present disclosure relates to acoustic wave devices, such as surface acoustic wave (SAW) devices. [Background technology]

[0003] Surface acoustic wave (SAW) resonators are typically interdigitated structures mounted on the surface of a piezoelectric layer. The interdigitated transducer (IDT) electrodes are located on the two interdigitated sets of fingers. In such a configuration, the distance between two adjacent fingers of the same set is suppressed by the IDT electrodes. is approximately equal to the wavelength λ of the surface acoustic wave being propagated.

[0004] In many applications, the SAW resonator is used to generate radio frequency signals based on the wavelength λ. Such filters can be used as a filter that provides a certain number of desired characteristics. can be given. Summary of the Invention

[0005] According to some implementations, the present disclosure provides an acoustic resonance technique that provides a resonance of a surface acoustic wave having a wavelength λ. This is a surface acoustic wave device. The surface acoustic wave device is made of a quartz substrate and LiTaO3 or LiN and a piezoelectric plate formed of .beta.O3 and disposed on the quartz crystal substrate. The surface acoustic wave device further includes an interlayer formed on the piezoelectric plate. The interdigital transducer electrodes include: 1.50g / cm 3 <ρ≦6.00g / cm 3 , 6.00g / cm 3 <ρ≦12.0g / cm 3 , or 12.0 g / cm 3 <ρ≦23.0g / cm 3 With mass density ρ in the range and, respectively, larger than 0.148λ, larger than 0.079λ, or 0 Has a thickness greater than .036λ.

[0006] In some embodiments, the interdigital transducer electrodes are approximately It may have a metallization ratio (MR) of 0.5, where MR=F / (F+G). where F is the width of the electrode finger and G is the gap between the two electrode fingers. In an embodiment, the interdigital transducer electrodes have a mass density in the range of 1.5 0g / cm 3 <ρ≦23.0g / cm 3 Aluminum, titanium, magnesium, copper , nickel, silver, molybdenum, gold, platinum, tungsten, tantalum, hafnium, other gold metals, alloys formed from multiple metals, or multi-layer structures.

[0007] In some embodiments, the piezoelectric plate may be a LiTaO3 (LT) plate. ,(0±5°,80~155°,0±5°),(90±5°,90°±5°,0~180 3.°), or equivalent orientation angles of Euler angles.

[0008] In some embodiments, the piezoelectric plate may be a LiNbO3 (LN) plate. ,(0±5°,60~160°,0±5°),(90±5°,90°±5°,0~180 3.°), or equivalent orientation angles of Euler angles.

[0009] In some embodiments, the quartz substrate is (0±5°,θ,35°±8°), (10 °±5°,θ,42°±8°), (20°±5°,θ,50°±8°), (0°±5°, θ,0°±5°), (10°±5°,θ,0°±5°), (20°±5°,θ,0°±5 °), (0°±5°,θ,90°±5°), (10°±5°,θ,90°±5°),(2 0°±5°,θ,90°±5°),(90°±5°,90°±5°,ψ), or these and The Euler angles can be configured to be equivalent orientation angles, where θ and ψ are , has a value in the range of 0° to 180°.

[0010] In some implementations, the present disclosure provides an elastic surface acoustic wave resonator that provides resonance of a surface acoustic wave having a wavelength λ. The present invention relates to a method for manufacturing a surface wave device. The method includes forming or providing a quartz substrate. A piezoelectric plate made of LiTaO3 or LiNbO3 is placed on the quartz substrate. and mounting the piezoelectric plate on the quartz substrate, the piezoelectric plate being larger than 2λ. The method further comprises the steps of: providing an interdigital transducer electrode on the piezoelectric plate; forming a pole, the interdigital transducer electrode being 1.50 g / cm 3 <ρ≦6.00g / cm 3 , 6.00g / cm 3 <ρ≦12.0g / cm 3 ,also is 12.0g / cm 3 <ρ≦23.0g / cm 3 have mass densities ρ in the range Correspondingly, the values ​​are greater than 0.148λ, greater than 0.079λ, or greater than 0.036λ. has a thickness greater than

[0011] In some embodiments, mounting the piezoelectric plate comprises mounting a relatively thick piezoelectric plate and a quartz plate. The mounting of the piezoelectric plate may further include forming or providing an assembly with the piezoelectric plate. Then, a thinning process is performed on the relatively thick piezoelectric plate to obtain a piezoelectric plate having a thickness greater than 2λ. providing a piezoelectric plate having a first surface that engages the quartz plate; and an opposing second surface resulting from the thinning process.

[0012] In some embodiments, the thinning process may include a polishing process. In an embodiment, forming an interdigital transducer electrode on a piezoelectric plate. forming an interdigital transducer electrode on a second surface of the piezoelectric plate. In some embodiments, the quartz plate of the assembly is substantially the same as the quartz substrate. You may.

[0013] In some embodiments, mounting the piezoelectric plate involves using a relatively thick piezoelectric plate and a handheld The method may include forming or providing an assembly with a ring substrate. It is further known that a relatively thick piezoelectric plate can be thinned to a thickness greater than 2λ by a thinning process. providing a thinned piezoelectric plate having a thickness resulting from the thinning process; The handle substrate includes a first surface adapted to engage with the handle and a second surface opposite the first surface adapted to engage with the handle substrate. The thinning process may include, for example, a polishing process.

[0014] In some embodiments, mounting the piezoelectric plate further comprises: mounting the quartz crystal plate to a thinned piezoelectric plate. The step of mounting the piezoelectric plate may further include attaching the piezoelectric plate to a handling substrate. removing the plate to expose the second surface of the thinned piezoelectric plate. This may include, for example, an etching process.

[0015] In some embodiments, an interdigital transducer electrode is disposed on the piezoelectric plate. forming an interdigital transducer electrode on the exposed second surface of the piezoelectric plate; In some embodiments, the piezoelectric plate may include a first surface on which the first surface is attached. The quartz plate may be substantially the same as the quartz substrate.

[0016] In a number of implementations, the present disclosure provides a method for filtering signals by using an input node that receives a signal and a filtered signal. and an output node providing a rectified signal. further comprising an elastic surface mounted to be electrically present between the input node and the output node. The surface acoustic wave device is configured to provide resonance for a surface acoustic wave having a wavelength λ. A quartz substrate and a LiTaO3 or LiNbO3 film are arranged on the quartz substrate. and a piezoelectric plate placed on the surface of the piezoelectric substrate. The piezoelectric plate has a thickness greater than 2λ. The piezoelectric plate further includes an interdigital transducer electrode formed on the piezoelectric plate. The center digital transducer electrodes are 1.50 g / cm 3 <ρ≦6.00g / cm 3 , 6.00g / cm 3 <ρ≦12.0g / cm 3 , or 12.0 g / cm 3 <ρ≦23 .0g / cm 3and the mass density ρ is in the range of 0.148λ or more. The thickness may be greater than 0.079λ or greater than 0.036λ.

[0017] According to a number of implementations, the present disclosure relates to a radio-frequency module. A packaging substrate configured to receive a component; A radio frequency circuit configured to support one or both of the transmission and reception of signals. The radio frequency module further includes a filter for at least some of the signals. The radio frequency filter is configured to filter a wavelength λ. The surface acoustic wave device is configured to provide a resonance of a surface acoustic wave having a surface acoustic wave surface. The surface wave device is formed of a quartz substrate and LiTaO3 or LiNbO3. and a piezoelectric plate disposed on the plate. The piezoelectric plate has a thickness greater than 2λ. The wave device further includes an interdigital transducer electrode formed on the piezoelectric plate. The interdigital transducer electrodes are 1.50 g / cm 3 <ρ≦6.0 0g / cm 3 , 6.00g / cm 3 <ρ≦12.0g / cm 3 , or 12.0 g / cm 3 <ρ≦23.0g / cm 3 and 0.14 Having a thickness greater than 8λ, greater than 0.079λ, or greater than 0.036λ do.

[0018] In some teachings, the present disclosure provides a method for transmitting and receiving a signal from a transmitter and a receiver. The present invention relates to a wireless device including an antenna and a wireless system electrically mounted between the antenna and the wireless system. The system includes a filter configured to provide a filtering function for the wireless system. The filter includes a surface acoustic wave filter configured to provide resonance for a surface acoustic wave having a wavelength λ. The surface acoustic wave device includes a quartz substrate and a LiTaO3 or LiNbO 3 and a piezoelectric plate disposed on the quartz crystal substrate. The piezoelectric plate has a length greater than 2λ. The surface acoustic wave device further includes an interdigital transducer formed on the piezoelectric plate. The interdigital transducer electrodes include: 1. 50g / cm 3 <ρ≦6.00g / cm 3 , 6.00g / cm 3 <ρ≦12.0g / cm 3 , or 12.0 g / cm 3 <ρ≦23.0g / cm 3 and having a mass density ρ in the range The corresponding values ​​are greater than 0.148λ, greater than 0.079λ, or 0.0 It has a thickness greater than 36λ.

[0019] According to some implementations, the present disclosure provides an acoustic resonance technique that provides a resonance of a surface acoustic wave having a wavelength λ. This is a surface acoustic wave device. The surface acoustic wave device is made of a quartz substrate and LiTaO3 or LiN and a piezoelectric plate formed of .beta.O3 and disposed on the quartz crystal substrate. The surface acoustic wave device further includes an interlayer formed on the piezoelectric plate. The interdigital transducer electrodes include: mass density ρ, and

number

[0020] In some embodiments, the metallization of the interdigital transducer electrodes The rotation ratio (MR) can be estimated as F / (F+G), where the quantity F is is the width of the electrode finger, and quantity G is the gap dimension between two electrode fingers. In this case, the metallization ratio (MR) may have a value of approximately 0.5.

[0021] In some embodiments, the quantity δ a is (0.10)0.19091λ, (0.0 9)0.19091λ, (0.08)0.19091λ, (0.07)0.19091λ , (0.06)0.19091λ, (0.05)0.19091λ, (0.04)0.1 9091λ, (0.03)0.19091λ, (0.02)0.19091λ, (0.0 1) 0.19091λ, or a value approximately equal to zero. , quantity δ b are (0.10)0.17658λ, (0.09)0.17658λ, (0. 08)0.17658λ, (0.07)0.17658λ, (0.06)0.17658 λ, (0.05)0.17658λ, (0.04)0.17658λ, (0.03)0. 17658λ, (0.02)0.17658λ, (0.01)0.17658λ, or close In some embodiments, the quantity δ c is (0.10)9 .08282g / cm 3 , (0.09)9.08282g / cm 3 , (0.08) 9.0 8282g / cm 3 , (0.07)9.08282g / cm 3 , (0.06)9.082 82g / cm 3 , (0.05)9.08282g / cm 3 , (0.04)9.08282 g / cm 3 , (0.03)9.08282g / cm 3 , (0.02) 9.08282g / cm 3 , (0.01)9.08282g / cm 3 , or may have a value approximately equal to zero.

[0022] In some embodiments, the piezoelectric plate may be a LiTaO3 (LT) plate. In the embodiment, the LT plate is (0±5°, 80~155°, 0±5°), (90±5 90°±5°, 0 to 180°), or equivalent Euler angles It can be configured as follows.

[0023] In some embodiments, the piezoelectric plate may be a LiNbO3 (LN) plate. ,(0±5°,60~160°,0±5°),(90±5°,90°±5°,0~180 3.°), or equivalent orientation angles of Euler angles.

[0024] In some embodiments, the quartz substrate is (0±5°,θ,35°±8°), (10 °±5°,θ,42°±8°), (20°±5°,θ,50°±8°), (0°±5°, θ,0°±5°), (10°±5°,θ,0°±5°), (20°±5°,θ,0°±5 °), (0°±5°,θ,90°±5°), (10°±5°,θ,90°±5°),(2 0°±5°,θ,90°±5°),(90°±5°,90°±5°,ψ), or these and The Euler angles can be configured to be equivalent orientation angles, where θ and ψ are , has a value in the range of 0° to 180°.

[0025] In some teaching examples, the present disclosure provides an elastic surface acoustic wave resonator that provides resonance of a surface acoustic wave having a wavelength λ. The present invention relates to a method for manufacturing a surface wave device. The method includes forming or providing a quartz substrate. The method further includes: bonding a piezoelectric plate made of LiTaO3 or LiNbO3 to a quartz crystal. and mounting the piezoelectric plate on a substrate, the piezoelectric plate having a thickness greater than 2λ. The method further comprises forming an interdigital transducer electrode on the piezoelectric plate. the interdigital transducer electrodes having a mass density ρ, and

number

[0026] In some embodiments, mounting the piezoelectric plate comprises mounting a relatively thick piezoelectric plate and a quartz plate. The mounting of the piezoelectric plate may further include forming or providing an assembly with the piezoelectric plate. Then, a thinning process is performed on the relatively thick piezoelectric plate to obtain a piezoelectric plate having a thickness greater than 2λ. providing a piezoelectric plate having a first surface that engages the quartz plate; and an opposing second surface resulting from the thinning process. This may include a polishing process.

[0027] In some embodiments, the interdigital transducer electrodes are disposed on the piezoelectric plate. forming an interdigital transducer electrode on the second surface of the piezoelectric plate; In some embodiments, the quartz plate of the assembly may include a quartz substrate. It may be substantially the same.

[0028] In some embodiments, mounting the piezoelectric plate involves using a relatively thick piezoelectric plate and a handheld The method may include forming or providing an assembly with a ring substrate. It is further known that a relatively thick piezoelectric plate can be thinned to a thickness greater than 2λ by a thinning process. providing a thinned piezoelectric plate having a thickness resulting from the thinning process; The handle substrate includes a first surface adapted to engage with the handle and a second surface opposite the first surface adapted to engage with the handle substrate. The thinning process may include, for example, a polishing process.

[0029] In some embodiments, mounting the piezoelectric plate further comprises: mounting the quartz crystal plate to a thinned piezoelectric plate. The step of mounting the piezoelectric plate may further include attaching the piezoelectric plate to a handling substrate. Removing the handling substrate to expose the second surface of the thinned piezoelectric plate. , for example, etching processes.

[0030] In some embodiments, the interdigital transducer electrodes are disposed on the piezoelectric plate. forming an interdigital transducer electrode on the exposed second surface of the piezoelectric plate; In some embodiments, the piezoelectric plate may include a first surface on which the first surface is attached. The quartz plate may be substantially the same as the quartz substrate.

[0031] According to some implementations, the present disclosure provides a method for filtering a signal by using an input node that receives the signal; and an output node providing a rectified signal. The converter further includes an elastic substrate mounted to be electrically located between the input node and the output node. Surface acoustic wave devices include surface acoustic wave devices that provide resonance of a surface acoustic wave having a wavelength λ. The crystal substrate is made of LiTaO3 or LiNbO3. and a piezoelectric plate disposed on the plate. The piezoelectric plate has a thickness greater than 2λ. The wave device further includes an interdigital transducer electrode formed on the piezoelectric plate. The interdigital transducer electrodes have a mass density ρ, and

number

[0032] According to some implementations, the present disclosure may be configured to receive multiple components. and a packaging substrate for transmitting and receiving signals mounted on the packaging substrate. and a radio frequency module including a radio frequency circuit configured to support either or both of the The radio frequency module further comprises filtering at least some of the signals. The radio frequency filter includes a filter having a wavelength λ. The surface acoustic wave device includes a surface acoustic wave device configured to provide resonance of a surface acoustic wave corresponding to the surface acoustic wave. The device is made of a quartz substrate and LiTaO3 or LiNbO3. and a piezoelectric plate disposed on the surface of the piezoelectric substrate. The piezoelectric plate has a thickness greater than 2λ. The chair further includes an interdigital transducer electrode formed on the piezoelectric plate. The interdigital transducer electrodes have a mass density ρ, and

number

[0033] In some teachings, the present disclosure provides a method for transmitting and receiving a signal from a transmitter and a receiver. The present invention relates to a wireless device including an antenna and a wireless system electrically mounted between the antenna and the wireless system. The system includes a filter configured to provide a filtering function for the wireless system. The filter includes a surface acoustic wave filter configured to provide resonance for a surface acoustic wave having a wavelength λ. The surface acoustic wave device is made of a quartz substrate and LiTaO3 or LiNbO3. and a piezoelectric plate formed from the piezoelectric material and disposed on the quartz crystal substrate. The surface acoustic wave device further comprises an interdigital transducer formed on the piezoelectric plate. The interdigital transducer electrodes include mass density ρ, and

number

[0034] For purposes of summarizing this disclosure, certain aspects, advantages and novel features of the invention have been identified herein. Not all such advantages may be realized with any particular embodiment of the invention. It should be understood that the present invention is not accomplished according to the above-mentioned embodiment. One of the advantages taught herein may be achieved without necessarily achieving other advantages that may be taught or suggested herein. It may be embodied or carried out in a manner that achieves or optimizes an advantage or group of advantages. do. [Brief description of the drawings]

[0035] [Figure 1] Depicts a surface acoustic wave device that includes a transducer mounted on a piezoelectric material. When electromagnetic (EM) energy is applied to the piezoelectric material through the transducer, some or all of the EM energy is converted to acoustic energy that propagates from the transducer as surface acoustic waves. [Diagram 2]It is shown that the surface acoustic wave device of FIG. 1 can also function in reverse, such that some or all of the acoustic energy associated with a surface acoustic wave supported by a piezoelectric material is converted into EM energy via a transducer. [Diagram 3] It will be appreciated that in some embodiments, a surface acoustic wave device may include compliant electrodes configured to provide some or all of the transducer functionality of FIGS. [Figure 4] An example of a surface acoustic wave device is shown in which compliant electrodes are implemented as interdigital transducers (IDTs) on the surface of a piezoelectric layer having a thickness T. [Diagram 5] 1 illustrates an example of a surface acoustic wave (SAW) device implemented as a SAW resonator. [Figure 6] 6 shows an enlarged and isolated plan view of the IDT electrodes of the SAW resonator of FIG. 5. [Figure 7] The labeled cross-sectional views are shown in FIG. [Figure 8] 8A-8C show an example of a thinning process that can be used to obtain a thin piezoelectric plate, such as a thin LiTaO 3 (LT) plate. [Figure 9] 9A-9E show another example of a thinning process that can be used to obtain a thin piezoelectric plate, such as a thin LiTaO 3 (LT) plate. [Figure 10A] 8A-8C and 9A-9E. FIG. 8B is an example of a SAW resonator that can be formed by any of the processes of FIGS. [Figure 10B] 8A-8C and 9A-9E. FIG. 9B is a diagram showing another example of a SAW resonator that can be formed by any of the processes of FIGS. [Figure 11A] 11A-11D show several examples where a thicker LT plate may be preferable over a thinner LT plate. [Figure 11B] 11A-11D show several examples where a thicker LT plate may be preferable over a thinner LT plate. [Figure 11C] 11A-11D show several examples where a thicker LT plate may be preferable over a thinner LT plate. [Figure 11D]11A-11D show several examples where a thicker LT plate may be preferable over a thinner LT plate. [Figure 12] An example of a SAW resonator having an LT plate with a quartz plate attached to one side and an electrode formed on the other side is shown. [Figure 13] 13 shows a plot of the impedance characteristics of the SAW resonator of FIG. 12. [Figure 14] 1 shows another example of a SAW resonator having an LT plate with a quartz plate attached to one side and an electrode formed on the other side. [Figure 15] 15 shows a plot of the impedance characteristics of the SAW resonator of FIG. 14. [Figure 16] 1 shows yet another example of a SAW resonator having an LT plate with a quartz plate attached to one side and an electrode formed on the other side. [Figure 17] 17 shows a plot of the impedance characteristics of the SAW resonator of FIG. 16. [Figure 18] 1 shows yet another example of a SAW resonator having an LT plate with a quartz plate attached to one side and an electrode formed on the other side. [Figure 19] 19 shows a plot of the impedance characteristics of the SAW resonator of FIG. 18. [Figure 20] A plot of impedance ratio is shown as a function of LT plate thickness for different copper (Cu) electrode thicknesses. [Figure 21] A plot of impedance ratio is shown as a function of LT plate thickness for different aluminum (Al) electrode thicknesses. [Figure 22] 1 shows a plot of impedance ratio as a function of piezoelectric thickness for a SAW resonator with a generalized combination of a piezoelectric plate and electrodes mounted thereon. [Diagram 23] 1 illustrates an example of the relationship between electrode thickness threshold and density for electrode materials including aluminum, copper, and gold. [Figure 24] 1 illustrates another example of the relationship between electrode thickness threshold and electrode material density for a given number of materials. [Diagram 25] In some embodiments, we demonstrate that multiple units of SAW resonators can be fabricated while in an array format. [Figure 26] It will be appreciated that in some embodiments, a SAW resonator having one or more features described herein can be implemented as part of a packaged device. [Figure 27] It is shown that in some embodiments, the SAW resonator-based packaged device of FIG. 26 can be a packaged filter device. [Figure 28] It is noted that in some embodiments, a radio frequency (RF) module can include an assembly of one or more RF filters. [Figure 29] 1 illustrates an example of a wireless device having one or more advantageous features described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Headings provided herein, if any, are for convenience only and do not necessarily reflect the It does not affect the scope or meaning of the invention.

[0037] FIG. 1 shows a surface acoustic wave device including a transducer 12 mounted on a piezoelectric material 14. Electromagnetic (EM) energy is applied to a piezoelectric material 14 via a transducer 12. When used, some or all of the EM energy is converted into acoustic energy. At least a portion of the acoustic energy propagates from the transducer 12 as a surface acoustic wave 16. do.

[0038] FIG. 2 shows that the surface acoustic wave device 10 can also function in reverse. As a result, the piezoelectric material A portion or all of the acoustic energy associated with the surface acoustic wave 18 supported by 14 All of this is converted into EM energy via the transducer 12. The transducer 12 in FIG. 2 may be the same as the transducer 12 in FIG. The transducer 12 may be a separate transducer added to the first transducer 12. In the latter configuration, where a transducer is provided, the corresponding surface acoustic wave device is, for example, In such an application, the transducer may be used as a surface acoustic wave filter. The transducer 12 is configured so that the surface acoustic wave has a selected resonant frequency, so that E Incoming EM energy in the form of an M signal is converted into an outgoing EM signal that corresponds to the resonant frequency of the surface acoustic wave. Filtered to give energy.

[0039] FIG. 3 illustrates, in some embodiments, a surface acoustic wave device 100 in accordance with the topology of FIGS. It is shown that the device may include a conformal electrode 102 configured to provide a transducer function. In general, the compliant electrode 102 generates a surface acoustic wave 106 (electrode) supported by a piezoelectric material 104. 102 or towards the electrode 102) for a given volume of the piezoelectric material 104. The filter 108 may be configured to have desired performance characteristics for the filter 108. In the context of the application example, the desired performance characteristics of the surface acoustic wave 106 are A filtered EM signal may also result in desirable performance characteristics.

[0040] As can be seen, if the electrodes are not adapted to a volume (e.g., volume 108), then the volume 1 Acoustic energy driven into or received from volume 108. In such a situation, the resulting EM signal may be The signal may contain undesirable noise and / or other artifacts, and the corresponding This can degrade the performance of the surface acoustic wave device.

[0041] That is, in some embodiments, the compliant electrode 102 of FIG. When driven into or received from the volume 108 of the piezoelectric material 104, In some embodiments, such compliant electrodes may be configured to be electrically stable. The physically stable characteristics of the electrode 102 are provided by the appropriate mass increase of the electrode 102. , depending on one or more factors such as the material used for the piezoelectric 104 and the size of the volume 108. For purposes of this description, the appropriately mass-increasing feature of such a compliant electrode 102 will be referred to as mass loading. Examples of how electrodes can be mass loaded are detailed herein.

[0042] FIG. 4 shows a compliant electrode 102 interleaved with a surface 110 of a piezoelectric layer 104 having a thickness T. FIG. 1 shows an example of a surface acoustic wave device 100 implemented as an IDT (interdigital transducer). In such a configuration, one or more fingers of the first set interdigitate with one or more fingers of the second set. (frequency f RF Such as radio frequency (RF) signals When M signals are applied to each terminal of the first and second sets of fingers, a wavelength λ ACOUST IC A surface acoustic wave 108 having a wavelength λ ACOUST IC When a surface acoustic wave 108 having a frequency f RF As can be seen, in the above configuration, an RF signal having a wave Long λ ACOUSTIC is approximately equal to the distance between two adjacent fingers of the same set.

[0043] As shown in FIG. 4, the piezoelectric layer 104 can be a design element to which the electrodes 102 are fitted. Such a capacitance is based at least in part on the thickness (T) of the piezoelectric layer 104. Examples of pole 102 adaptations are detailed herein.

[0044] FIG. 5 illustrates an example of a surface acoustic wave (SAW) device 100 implemented as a SAW resonator. Such a SAW resonator may be made of, for example, LiTaO3 (herein, lithium tantalate or LiTaO3). T) or LiNbO3 (also referred to herein as lithium niobate or LN) The piezoelectric layer may include a piezoelectric layer 104 formed on a first surface 110 (e.g., a SAW The first surface, when the oscillator 100 is oriented as shown, may include a first surface, a second surface, and an opposing second surface. A second surface of the piezoelectric layer 104 is attached to a quartz substrate 112, for example.

[0045] The first surface 110 of the piezoelectric layer 104 includes an interdigital transducer (IDT). The electrode 102 may be implemented with one or more reflector assemblies (e.g., 114, 116). FIG. 6 is an enlarged and separated view of an example of the IDT electrode 102 of the SAW resonator 100 of FIG. It will be appreciated that the IDT electrodes 102 of FIGS. Or a reduced number of fingers may be included for two interlocking sets of fingers.

[0046] In the example of FIG. 6, the IDT electrodes 102 are arranged in a first set 120 in an interdigitated manner. The set of fingers 122a and the set of fingers 122b are shown to include a first set 120a and a second set 120b. As such, two adjacent fingers of the same set (e.g., adjacent fingers 122a of the first set 120a) ) is approximately equal to the wavelength λ of the surface acoustic wave associated with the IDT electrode 102. be.

[0047] In the example of FIG. 6, various dimensions associated with the fingers are shown. In particular, each finger (12 2a or 122b) are shown to have a lateral width F, and a gap distance G between two interlocking adjacent It is shown disposed between the contact fingers (122a and 122b).

[0048] FIG. 7 shows a cross-sectional view labeled in FIG. 6. Dimensions F and G are labeled with reference to FIG. As described above, each finger (122a or 122b) has a thickness T electrode Have FIG. 7 also shows that the piezoelectric layer 104 has a thickness T piezoelectric of It also indicates that it has

[0049] As can be seen, the SAW resonator 100 described with reference to FIGS. 5-7 can be used in a variety of applications, e.g. It can be configured to provide filtering functionality. As an example, it is understood that Mobile phones and smartphones use many frequency bands (e.g., almost 80 bands). However, some or all of these frequency bands are congested below 3.4 GHz, and adjacent The spacing between the frequency bands is very narrow, so interference between adjacent bands can be prevented. In order to prevent this, there is a strong demand or desire for an RF filter that has steep and good temperature characteristics. There are.

[0050] In some embodiments, desirable temperature characteristics, high Q, and / or high impedance ratios may be used. The filter that gives the value is made of LiTaO3 (here, LiTaO3) which has a negative temperature coefficient of frequency (TCF). The positive TCF of a LiNbO3 (also referred to here as LN) thin plate or a LiNbO3 (also referred to here as LN) thin plate This can include a combination with a quartz crystal having an orientation angle for improving T Desired performance characteristics such as CF and high impedance ratio can be obtained. Typically, LT or LN sheets are relatively thin (e.g., approximately less than 1 μm). Such thin LT or LN sheets can be obtained by a thinning process. Therefore, during a thinning process such as a polishing process, issues such as yield and / or cost may arise. may occur.

[0051] Various examples are described herein in the context of the piezoelectric layer or plate being a LT layer or plate. It will be appreciated that one or more features of the present disclosure may be used with other piezoelectric layers, including, for example, LN layers or LN plates. Or it can be mounted on a piezoelectric plate.

[0052] 8A-8C show the thinning process that can be used to obtain the thin LT plate described above. As will be appreciated, the thinning process example of FIGS. 8A-8C is not limited to the embodiments described herein. It may also be used to obtain a LT plate associated with a matching electrode having one or more characteristics. do.

[0053] 9A-9E show another example of a thinning process that can be used to obtain the thin LT plate described above. It will be understood that the example thinning process of FIGS. 9A-9E may be implemented using one or more of the methods described herein. It can also be used to obtain a LT plate associated with a compatible electrode having the following characteristics:

[0054] In a first example, FIG. 8A illustrates that in some embodiments, the thinning process includes: An assembly 132 of a relatively thick LT plate 130 and a quartz plate 112 is formed or provided. The process steps may include:

[0055] FIG. 8B shows the thickness of the relatively thick LT plate 130 being reduced to a thin 1 shows the process steps reduced to a thin LT plate 134. Such thinning process steps may include, for example, mechanical polishing processes, chemical mechanical processes, etc. In FIG. 8B, a thin LT plate is 134 is a first surface that engages the quartz plate 112 (either directly or through an intermediate layer) and a first surface and a second surface resulting from the thinning process step, opposite the face.

[0056] FIG. 8C shows the assembly 138 as a result of the formation of the electrode 102 on the second surface of the LT plate 134. As described herein, such electrodes are formed on the fingers 12. 2a, 122b interdigitating sequences.

[0057] In some embodiments, some of the process steps associated with FIGS. Or all for one individual unit to produce a single unit of assembly 138. 138, and can be assembled in multiple steps to produce multiple corresponding single units of assembly 138. 1, and the assembly 138 can be implemented with multiple individual units. A number of units to be manufactured and diced are taken in an array format (e.g., wafer format). It can be implemented while attached to the This can be done.

[0058] In a second example, FIG. 9A illustrates that in some embodiments, the thinning process includes: The assembly of a relatively thick LT plate 130 and a handling substrate (e.g., a silicon substrate) 140 is This may include process steps by which bridge 142 is formed or provided.

[0059] FIG. 9B shows the thickness of the relatively thick LT plate 130 being reduced to a thin 1 shows the process steps reduced to a thin LT plate 144. Such thinning process steps may include, for example, mechanical polishing processes, chemical mechanical processes, etc. In FIG. 9B, a thin LT plate is 144 is a first surface obtained by the thinning process step and a ha and a second surface that is attached to the bonding substrate 140.

[0060] FIG. 9C shows the first surface of the LT plate 144 attached to the quartz plate 112, resulting in an assembly. 148 is formed. In some embodiments, the LT plate 14 The first surface of the crystal substrate 112 is attached to the crystal plate 112 directly or via an intermediate layer (e.g., a solder joint). (to be combined).

[0061] FIG. 9D shows the partial or partial removal of the handling substrate (140 in FIG. 9C). 1 shows the process step where the LT plate 144 is completely exposed and the assembly 150 is formed. In some embodiments, such a handling substrate (e.g., a silicon substrate) Removal of the can be accomplished, for example, by an etching process. In this embodiment, the LT plate 144 in the assembly 150 of FIG. 9D is the same as the assembly 1 in FIG. 48. The LT plate 144 may or may not be substantially the same as the LT plate 144 in 48. As will be appreciated, the exposed surface resulting from removal of the handling substrate may be as shown in FIG. 9B. LT plate 144.

[0062] FIG. 9E shows the assembly 152 as a result of the formation of the electrode 102 on the second surface of the LT plate 144. As described herein, such electrodes are formed on the fingers 12. 2a, 122b interdigitating sequences.

[0063] In some embodiments, some of the process steps associated with FIGS. Or all for one individual unit to produce a single unit of assembly 152. 152 to produce a plurality of corresponding single units of the assembly 152. 1, and the assembly 152 may be implemented with multiple individual units. A number of units to be manufactured and diced are taken in an array format (e.g., wafer format). It can be implemented while attached to the This can be done.

[0064] FIG. 10A illustrates any of the processes described with reference to FIGS. 8A-8C and 9A-9E. 8A-8C are used to form a SAW resonator 100. In this case, the assembly 138 of FIG. 8C may be the SAW resonator 100 of FIG. 10A. When the process of FIG. 9E is utilized, the assembly 152 of FIG. 9E can be used to fabricate the SAW resonator of FIG. For purposes of description, the LT plate 104 having a thickness d1 may be considered a thin LT plate. Examples of thickness values ​​and / or ranges for such thin LT sheets are given below.

[0065] FIG. 10B illustrates any of the processes described with reference to FIGS. 8A-8C and 9A-9E. 8A-8C are used to form a SAW resonator 100. In this case, the assembly 138 of FIG. 8C may be the SAW resonator 100 of FIG. 10A. When the process of FIG. 9E is utilized, the assembly 152 of FIG. 9E can be used to fabricate the SAW resonator of FIG. For purposes of description, the LT plate 104 having a thickness d2 may be considered a thick LT plate. Examples of thickness values ​​and / or ranges for such thick LT plates are given below.

[0066] 11A to 11D show the thickness of the thick LT plate 104b (thickness d2) and the thickness of the thin LT plate 104a (thickness d This is a more preferable example than 1). In this example, even though the LT plate is drawn alone, Regardless of the type, the LT plate is attached to a corresponding substrate (e.g., a handling substrate and / or a quartz substrate). It is understood that some or all of the effects in the examples of Figures 11A-11D may be For a corresponding LT plate, regardless of whether such LT plate is attached to other parts or not , it is also understood to appear.

[0067] For example, referring to FIG. 11A, a thin LT plate 104a typically has a small resistance to the application of a given force. In another example, referring to FIG. 11B, the thin LT plate 104b is more likely to break than the thick LT plate 104b. A thin LT plate 104a typically has a lower warpage than a thick LT plate 104b for a given warpage condition. water.

[0068] As can be seen, in some applications, the performance of SAW resonators is It may depend on the uniformity of the plate thickness. That is, referring to FIG. 11C, the LT plate may have a tilted As a result of the oblique thinning process, the thickness may be non-uniform. For example, the thin LT plate 104a and the thick L Each of the T-plates 104b was similarly tilted and subjected to a thinning process, resulting in a wedge-shaped side profile. The thin LT plate 104a has an average thickness value d1, a high thickness value d1+Δd, and a low thickness value d Similarly, the thick LT plate 104b has an average thickness value d2, For each plate, the thickness is shown to have a higher thickness value d2+Δd and a lower thickness value d2-Δd. The relative error of can be estimated as Δd / (average thickness). That is, for the thick LT plate 104 b has a smaller relative error in thickness than the thin LT plate 104a for a given thickness error condition Δd. It becomes.

[0069] In the example of FIG. 11C, the thickness error term Δd is due to the error introduced by the thinning process. FIG. 11D shows that such a thinning process results in a uniform average thickness for the plate. However, the surface of the plate may be affected, for example, by the thinning process itself or by other factors related to the plate. The semiconductor device may have defects resulting from the manufacturing steps up to and including the steps described above.

[0070] In FIG. 11D, such defects are formed on each surface of the thin LT plate 104a (average thickness d1). and on each surface of the thick LT plate 104b (average thickness d2), in an exaggerated manner. Assuming that each surface has a defect error of δ, the relative error in thickness is 2δ / (average thickness That is, the thick LT plate 104b can be estimated as a given surface defect error. For the difference condition δ, it will have a lower relative error than the thin LT plate 104a.

[0071] The examples described with reference to Figures 11A to 11D show that thicker LT plates are preferable to thinner LT plates. However, simply increasing the thickness of the LT plate can result in a deterioration of performance.

[0072] Figures 12 to 19 show four examples of SAW resonators with different combinations of LT plates and electrodes. For example, FIG. 12 shows a crystal plate attached to one side and electrodes attached to the other side. 12 shows a SAW resonator with a LT plate. With reference to the dimensions shown in FIG. 7, the LT plate of FIG. is the thickness T piezoelectric = 0.15 λ and is formed from copper. The electrodes are of thickness T electrode = 0.06λ.

[0073] FIG. 13 shows a plot of the impedance characteristics of the SAW resonator of FIG. And the resonant frequency f r and anti-resonance frequency f a is shown, and the corresponding in The impedance values ​​are Z r and Z a For the examples in Figures 12 and 13, Dance ratio (20log(Z a / Z r )) is 78 dB, and the in-band ripple is essentially There is no spurious response at high frequencies and little or no spurious response is observed at high frequencies. .

[0074] In another example, FIG. 14 shows a crystal plate attached to one side and an electrode attached to the other side. 14 shows a SAW resonator with a LT plate. With reference to the dimensions shown in FIG. 7, the LT plate of FIG. is the thickness T piezoelectric = 3λ, and the current formed from copper The pole has a thickness of T electrode = 0.06λ.

[0075] FIG. 15 shows a plot of the impedance characteristics of the SAW resonator of FIG. And the resonant frequency f r and anti-resonance frequency f a is shown, and the corresponding in The impedance values ​​are Z r and Z a For the examples in Figures 14 and 15, Dance ratio (20log(Z a / Z r )) has a lower value than the examples of FIGS. 12 and 13, and There is significant in-band and out-of-band ripple. Therefore, the SAW resonator of FIG. 14 is not practical for many applications.

[0076] In yet another example, FIG. 16 shows a crystal plate attached to one side and electrodes attached to the other side. 16 shows a SAW resonator having a LT plate attached to it. With reference to the dimensions shown in FIG. The LT plate has a thickness of T piezoelectric = 5λ and formed from copper The electrodes are of thickness T electrode = 0.1λ.

[0077] FIG. 17 shows a plot of the impedance characteristics of the SAW resonator of FIG. And the resonant frequency f r and anti-resonance frequency f a is shown, and the corresponding in The impedance values ​​are Z r and Z a For the examples in Figures 16 and 17, -dance ratio (20log(Z a / Z r )) has a higher value than the examples of Figs. 14 and 15. Little or no in-band ripple, but large spurious at high frequencies That is, the SAW resonator in Figure 16 is suitable for many applications. Therefore, it may not be practical to

[0078] In yet another example, FIG. 18 shows a crystal plate attached to one side and electrodes attached to the other side. 18 shows a SAW resonator with a LT plate attached to it. With reference to the dimensions shown in FIG. The LT plate has a thickness of T piezoelectric = 50λ, and is made from copper. The electrodes are made of thickness T electrode = 0.12λ.

[0079] FIG. 19 shows a plot of the impedance characteristics of the SAW resonator of FIG. And the resonant frequency f r and anti-resonance frequency f a is shown, and the corresponding in The impedance values ​​are Z r and Z a For the examples in Figures 18 and 19, -dance ratio (20log(Z a / Z r )) has the same values ​​as in the examples of Figs. 12 and 13. There is virtually no in-band ripple, and the amplitude spurious responses observed at high frequencies are A little small.

[0080] A number of observations can be made from the examples in Figures 12 to 19. First, the SAW resonance in Figure 12 The vessel is made of thin LT board (T piezoelectric = 0.15λ) and the electrode is The appropriate thickness (T electrode = 0.06λ) For example, SAW resonators provide desirable performance, with no in-band ripple and high frequency response. There is little or no spurious response observed at any wave number. Then, the LT plate thickness is T piezoelectric = 3λ, but the electrode thickness increases significantly T electrode With reference to the SAW resonator of FIG. 14, where λ=0.06λ remains the same. The performance of the SAW resonator is severely impaired, resulting in in-band ripple and out-of-band ripple. From this comparison, it can be seen that simply increasing the thickness of the LT plate does not result in significant performance improvement. It is shown that degradation can occur.

[0081] Second, the SAW resonator (T piezoelectric = 3λ, T elect rode =0.06λ) and the SAW resonator in Fig. 16 (T piezoelectric =5λ , T electrode =0.1λ), the electrode thickness (0.06λ to 0.1 λ), even if the LT plate thickness (T piezoelectric = 3λ to T piezoelectric Even a further increase in From this comparison, it is shown that the increase in electrode thickness leads to a decrease in the performance for thick LT plates. These results suggest that this could be a factor that improves function.

[0082] Third, the SAW resonator (T piezoelectric = 5λ, T elect rode =0.1λ) and the SAW resonator in Fig. 18 (T piezoelectric =50λ , T electrode =0.12λ), the electrode thickness (0.1λ to 0.1 2λ), even if the LT plate thickness (T piezoelectric = 5λ to T piezoelectric Even if you increase it by just one order of magnitude (to 50λ), the performance will not improve. From this comparison, it is shown that the electrode thickness and / or the LT plate thickness are improved. It is shown that both can be factors that improve performance.

[0083] Figure 20 shows the impedance ratio plot for different copper (Cu) electrode thicknesses for the LT plate. In particular, curve 170 shows the thickness as a function of thickness T electrode is 0.06 λ to 0.079λ (thus including the examples of Figures 12 and 14). Curve 172 corresponds to a SAW resonator having a thickness T electrode Copper with a thickness of 0.08λ Curve 174 corresponds to a SAW resonator having copper electrodes. Thickness T electrode For a SAW resonator with a copper electrode of 0.25λ Respond.

[0084] For each of the three curves (170, 172, or 174) in FIG. SAW resonators that achieve this (as a function of frequency) are practical for many applications. Impedance ratio response with no (or sufficiently low amplitude) ripple or spurious responses The dashed lines correspond to the regions where the corresponding SAW resonators are impractical for many applications. have either or both of the ripple (as a function of frequency) and spurious responses that are of concern It corresponds to the impedance ratio response, i.e., the SAW resonator of FIG. Example data point 176 on curve 170 is deemed to provide acceptable performance and is consistent with the above description. The example data points 178 on curve 170 corresponding to the SAW resonator of FIG. is considered to give unacceptable performance for some applications.

[0085] A number of observations can be made from the impedance ratio plot of FIG. For copper electrode thicknesses up to a certain value (e.g., 0.079λ or nearby), the impedance ratio is highest for thin LT plates (e.g., 0.1λ) and decreases as the LT plate thickness increases. It can be seen that the impedance ratio gradually decreases monotonically. The range of lengths (e.g., 0.1 λ to about 2 λ) determines the acceptable performance of the corresponding SAW resonator. The thick range of the LT plate (e.g., more than 2λ) results in high ripple and / or spurious. This results in a sigma-like response, making the corresponding SAW resonators impractical for many applications. In the latter configuration, the LT plate is considered to be too thick for the corresponding copper electrode thickness. This can be done.

[0086] Second, for copper electrode thicknesses greater than the values ​​mentioned above (e.g., 0.079λ or thereabouts), However, the impedance ratio may be highest for a thin LT plate (e.g., 0.1 λ) or As the LT plate thickness increases, it may not be possible to achieve a nearly flat impedance. For purposes of description, such copper electrode thickness values ​​(e.g., 0.07 9λ or thereabouts) may be considered as the threshold thickness value.

[0087] The copper electrode thickness is greater than but close to the threshold value (e.g., In this case, the impedance ratio is similar to that for the copper electrode thicknesses described above below the threshold value: It has a maximum value for thin LT plates. However, for a certain LT thickness value (e.g., about 1λ), In general, the impedance ratio becomes approximately flat as the LT thickness increases. remains flat.

[0088] When the copper electrode thickness is significantly greater than this threshold, the impedance ratio is (e.g., 0.1λ) may or may not have a maximum value. For example, the impedance ratio curve 174, which corresponds to a significantly larger copper electrode thickness of 0.25λ, The impedance ratio value at the LT plate thickness of 0.1λ is small. This is because the impedance ratio at the high LT thickness It is almost the same as the impedance ratio value at which the plateau occurs. In such a configuration, the impedance ratio is It has an approximately flat response even beyond a certain thickness (e.g., about 1λ).

[0089] In the above-mentioned trend of the impedance ratio of the curves 172 and 174, the thick LT plate (e.g. For example, a range of about 2λ or greater may provide acceptable performance for a corresponding SAW resonator. The possible ripple and spurious responses are obtained by using thin LT plates (e.g. 0.1λ to 2λ ) range results in ripples and / or spurious responses, and the corresponding SAW resonators In the latter configuration, the LT plate has a corresponding The thickness of the copper electrode is too thin for this purpose.

[0090] Based on the above description of the example of FIG. 20, depending on the thickness of a given LT plate, the corresponding SAW It will be appreciated that the electrode thickness may be selected or tailored to provide the resonator with the desired performance. For example, if the LT plate is thinner than a certain thickness value, the corresponding SAW resonator will not have acceptable performance. It is possible to provide thin electrodes (e.g., having a thickness less than a threshold electrode thickness value) so as to have In the example, if the LT plate is thicker than a certain thickness value, the corresponding SAW resonator will have an acceptable It is possible to provide thick electrodes (e.g., thicknesses above the threshold electrode thickness value) to have performance. do.

[0091] Referring to FIG. 20, the copper electrode thickness range is 0.06λ to 0.079λ, whereas the LT plate thickness range is When the impedance is between 0.1 λ and 1.3 λ, a high impedance ratio of 70 to 78 dB is obtained. In the thickness range of 1.3λ to approximately 2λ, ripples or spurious responses were observed similar to the example in FIG. A slight or non-existent low impedance ratio of 68-70 dB is obtained. It can be seen that the copper electrode thickness ranges from 0.08λ to 0.25λ, whereas the LT plate thickness ranges from about 2λ. At about 200 λ, the spurious response is sufficiently small (as in the example of Figure 18). The impedance ratio is 71 to 73 dB (for example, 72 to 73 dB for a copper electrode thickness of 0.08 λ, 71 dB for a thickness of 0.25 λ, which allows many corresponding SAW resonators to be used. This is useful in applications such as:

[0092] In various examples described herein with reference to Figures 12-20, the electrodes are copper electrodes of various thicknesses. Assuming such electrodes have similar layout dimensions, the thick copper electrodes are thinner than the thin The LT plate has more mass than the electrodes. Therefore, the thickness of the LT plate is increased for the SAW resonator. Electrodes of increased mass can be utilized to provide the desired performance.

[0093] As can be seen, copper is one of the materials that can be used as electrodes for SAW resonators. This is just one example. Other conductive materials such as metals and / or alloys may also be used as SAW resonator electrodes. For example, FIG. 21 shows the relationship between L and different aluminum (Al) electrode thicknesses. 1 shows a plot of impedance ratio as a function of T-plate thickness. SaT electrode The aluminum electrodes have a wavelength of 0.081λ to 0.148λ. 182 corresponds to a SAW resonator having a thickness T electrode A of 0.15λ Curve 184 corresponds to a SAW resonator having aluminum electrodes, electrod e corresponds to a SAW resonator having aluminum electrodes of 0.35λ.

[0094] For each of the three curves (180, 182, or 184) in FIG. SAW resonators that achieve this (as a function of frequency) are practical for many applications. Impedance ratio response with no (or sufficiently low amplitude) ripple or spurious responses The dashed lines correspond to the regions where the corresponding SAW resonators are impractical for many applications. have either or both of the ripple (as a function of frequency) and spurious responses that are of concern Corresponds to the impedance ratio response.

[0095] A number of observations can be made from the impedance ratio plot of FIG. Impedance is measured for aluminum electrode thicknesses up to a certain value (e.g., 0.148λ or nearby). The impedance ratio is highest for thin LT plates (e.g., 0.1λ) and increases with increasing LT plate thickness. It can be seen that the impedance ratio gradually decreases monotonically as the impedance ratio increases. Depending on the range of the LT plate (e.g., 0.1λ to about 2λ), the allowable range of the corresponding SAW resonator performance, and the thick range of LT plates (e.g., over 2λ) reduces high ripple and / or sputtering. This results in premature responses, making the corresponding SAW resonators unsuitable for many applications. In the latter configuration, the LT plate is as thick as the corresponding aluminum electrode thickness. It can be considered too much.

[0096] Second, the aluminum current is greater than the value mentioned above (e.g., 0.148λ or its vicinity). The impedance ratio to thickness may be highest for thin LT plates (e.g., 0.1λ). This may or may not be the case, and eventually it will approximate the average as the LT plate thickness increases. For purposes of description, the aluminum electrode thickness is A thickness value (eg, 0.148λ or its vicinity) may be considered as a threshold thickness value.

[0097] For aluminum electrode thicknesses greater than but close to this threshold, the impedance ratio is Similar to the above-mentioned aluminum electrode thickness below the threshold, the maximum value is observed for thin LT plates. However, at a certain LT thickness value (e.g., about 1λ), the impedance ratio becomes approximately flat and generally remains approximately flat as the LT thickness increases. Impedance ratio curves 182, 184 each represent such an impedance ratio profile. Here is one example.

[0098] When the aluminum electrode thickness is significantly greater than this threshold, the impedance ratio is: It may or may not have the highest value for thin LT plates (e.g. 0.1λ). For example, if the aluminum electrode has a thickness significantly greater than 0.35λ (curve 184), Similarly, when the LT plate has a thickness of 0.1λ, the corresponding impedance ratio curves are also This is an impedance ratio that becomes flat at high LT thickness values. It is almost the same as the ratio value.

[0099] In the above example of the impedance ratio of curves 182 and 184, the thickness of the LT plate (e.g. For example, a range of about 2λ or greater may allow acceptable performance of a corresponding SAW resonator. The ripple and spurious response can be obtained with a thin LT plate (e.g., 0.1λ to 2λ). The range introduces ripples and / or spurious responses, and the corresponding SAW resonators are often In the latter configuration, the LT plate is The thickness of the aluminum electrode can be considered too thin.

[0100] Referring to FIG. 21, for the aluminum electrode thickness range of 0.081λ to 0.148λ, High impedance ratio of 70 to 78.5 dB when the LT plate thickness ranges from 0.1 λ to approximately 1.3 λ The ripple or spurious response was observed in the LT plate thickness range of 1.3λ to approximately 2λ. A slightly lower impedance ratio of 67.5 to 70 dB was obtained, with little or no impedance at all. It can be seen that the thickness of the aluminum electrode is in the range of 0.15λ to 0.35λ, whereas the thickness of the LT plate is Large out-of-band spurious responses are observed when the LT thickness is in the range of 0.1λ to approximately 2λ. For the wavelength range of 2λ to 200λ, the impedance ratio of 71 is sufficiently small for spurious responses. ~72 dB, making the corresponding SAW resonators suitable for many applications. As can be seen, this impedance ratio range (71-72 dB) is Impedance of about 65 dB obtained by a conventional SAW resonator with thin aluminum electrodes. It is about 6 to 8 dB higher than the dance ratio.

[0101] In another example, thickness T electrode Gold ( Au) is used as the electrode for the LT plate thickness range of 0.1λ to 2λ. It can provide an impedance ratio of 68 to 78 dB with little or no rear response. This makes the corresponding SAW resonators practical for many applications. For such an electrode thickness, if the LT plate is thick, either or both of the ripple and spurious response may occur. The presence of do.

[0102] On the other hand, thickness T electrode For gold electrodes with a wavelength in the range of 0.037λ to 0.12λ It also has over 70 dB of impedance with little or no ripple and low spurious response. This allows the impedance ratio to be obtained when the thickness is greater than 2λ (for example, 2λ to For a LT plate of 200 λ, the corresponding SAW resonator is practical for many applications. If the LT plate is thin compared to the electrode thickness, the ripple and spurious response are reduced. Since one or both exist, the corresponding SAW resonators are not suitable for many applications. Become practical.

[0103] Based on the examples of Figures 20 and 21 and the above description of the gold electrode configuration, for a given LT plate thickness Depending on the thickness of the electrode, the mass of the electrode may be selected to provide the desired performance for the corresponding SAW resonator. It will be appreciated that such mass may be adapted based on, for example, electrode density and / or size. In some embodiments, the electrode density can be selected based on the material of the electrodes. In some embodiments, the electrode dimensions can be selected based on the thickness of the electrode. The selection can be based on:

[0104] FIG. 22 shows a piezoelectric plate (for example, an LT plate or an LN plate) and an electrode (for example, a metal electrode) to be mounted. The impedance (as a function of piezoelectric thickness) for a SAW resonator with a general combination of 1 shows an impedance ratio plot of the thickness threshold T threshold The thickness T electrode and the impedance The impedance ratio curve 192 is threshold Thickness T greater than elect rode Such a thickness threshold T threshold Here is an example of is detailed in.

[0105] As in the examples of FIGS. 20 and 21, in the example of FIG. 22, the actual values ​​of the curves 191 and 192 are The line segments are the lips that make the corresponding SAW resonators practical for many applications. corresponding to an impedance ratio response that is free (or has sufficiently low amplitude) of loop or spurious responses, The dashed lines indicate the limits at which the corresponding SAW resonators become impractical for many applications. The impedance ratio response may include a single-ended and / or spurious response.

[0106] In the example of FIGS. 20 and 21 and the gold electrode configuration, and as can be seen with further reference to FIG. , thickness value T threshold (as in curve 191) thres hold With electrodes thinner than this, the corresponding SAW resonator can be made thinner than T1 piezo Thickness of less than For a thin piezoelectric plate (also referred to as a piezoelectric body here) having a gives solid line performance with no response (or low enough amplitude) and T1 piezo having a thickness of less than gives dashed-line performance (ripple and / or spurious response) for thick piezoelectrics Furthermore, (as in curve 192) T threshold Thicker than The electrodes cause the corresponding SAW resonators to piezo A thick pressure plate having a thickness greater than Real-line performance (no (or sufficiently low amplitude) ripple or spurious responses) for dielectrics Given T2piezo The dashed line performance (ripple and This results in either one or both of the following spurious responses:

[0107] As can be seen, the thickness value T1 piezo and T2 piezo may be the same, Although it is not necessary, for purposes of description of some specific examples, such values ​​are assumed to be approximately the same. Table 1 shows such piezoelectric thicknesses for examples associated with copper, aluminum, and gold electrodes. Value T piezo ≒T1 piezo ≒T2 piezo , but electrode T threshold value It is listed together with. [Table 1]

[0108] In the example of Table 1, the piezoelectric material is LT, and the value T corresponding to such LT material is piezo , and T of different metal electrodes threshold It is understood that T piezo and T threshold The values ​​are also taken for other piezoelectric materials, including LN materials. It is also understood that T piezo Even if it depends on the material, It doesn't have to be an arm, T threshold may or may not be material dependent. For example, for a SAW resonator using an LN plate, the thickness value T piezo Associated with LT board The thickness value may or may not be the same as that of the LN plate-based SA. For the W resonator, the T of different metal electrodes threshold The values ​​are for the LT plate-based SAW It may or may not be similar to that associated with the oscillator.

[0109] In some embodiments, for purposes of description, a piezoelectric layer (herein referred to as a piezoelectric plate, a piezoelectric film, or a single The thickness of the piezoelectric body is T piezo If it is less than this, it is thin Consider it as a piezoelectric layer, and its thickness is T piezo If it is larger than Also for purposes of description, the electrodes corresponding to the piezoelectric layers described above are referred to as having a thickness of T thresh old If the thickness is less than T, it is considered a thin electrode. threshold If it is greater than It can be considered as a thick electrode.

[0110] As described herein, the electrodes of the SAW resonator may be made of copper, aluminum, or other metals such as gold. It will be appreciated that other metals, alloys, etc. may be used. Other conductive materials, including, for example, SiO 2 , SiO 3 , and SiO 4 may also be used as electrodes for SAW resonators having one or more of the features described herein. Table 2 lists, but is not limited to, metals that can be used as such electrodes. Examples of this are given. [Table 2]

[0111] As described herein with reference to FIGS. 20-22 and Table 1, the electrode thickness threshold T th reshold decreases as the electrode material density increases. Figure 23 shows such a relationship. The relationship is plotted for the examples of aluminum, copper and gold. As can be seen, such data points is the electrode thickness threshold T threshold as a function of the mass density of the electrode material. Such curve and / or a set of data points representing such curve may be part of 194. The points can be obtained, for example, by empirical measurement, calculation, extrapolation, interpolation, modeling, etc. It will also be appreciated that such a curve, and / or a set of data representing such a curve, may be Data points can also be obtained for more than one piezoelectric material. For example, a set of T th reshold Values ​​may be obtained and are applicable to both LT and LN materials. In another example, the first set of T threshold values ​​may be used for LT materials, T in the second set threshold Values ​​may be used for LN materials.

[0112] FIG. 24 shows the electrode thickness threshold T threshold is shown as a circle. In some embodiments, such T threshold The value is given by Equation 1 This can be represented by a curve (194 in FIG. 23) that follows:

number

[0113] As can be seen, the metallization ratio MR of a given electrode is (associated with Figs. 12-21) (as in various examples given) is 0.5, and T in Eq. thresholdto Equation 2 It can be reduced as follows.

number

[0114] In some embodiments, T threshold According to Equation 1 or 2, the parameter Calculations may be made with one or more deviations from the specific example values ​​of data a, b and c above. For example, if the value of a in the above example is taken as a0 = 0.19091, the parameter Ta a is a = a0 ± 0.10a0, a = a0 ± 0.09a0, a = a0 ± 0.08a0, a=a0±0.07a0, a=a0±0.06a0, a=a0±0.05a0, a=a0 ±0.04a0, a=a0±0.03a0, a=a0±0.02a0, or a=a0±0 Similarly, the above example value for b would be considered as b0 = 0.17658. In this case, the parameter b is b=b0±0.10b0, b=b0±0.09b0, b=b0 ±0.08b0, b=b0±0.07b0, b=b0±0.06b0, b=b0±0.0 5b0, b=b0±0.04b0, b=b0±0.03b0, b=b0±0.02b0, Or b=b0±0.01b0. Similarly, the above example value of c can be c0=9.08 When the parameter c is considered as 282, c = c0 ± 0.10c0, c = c0 ± 0.0 9c0, c=c0±0.08c0, c=c0±0.07c0, c=c0±0.06c0, c=c0±0.05c0, c=c0±0.04c0, c=c0±0.03c0, c=c0 It may have a value of ±0.02c0, ​​or c=c0±0.01c0.

[0115] In some embodiments, specific example values ​​a0=0.19091, b0=0.1765 8, and c0 = 9.08282, T in Eq. 1 or 2 threshold song The line is T 0 threshold If it is considered that, T threshold The curve represents the thickness of the electrode. For example, T threshold The curve is T threshol d =T 0 threshold ±0.10T 0 threshold ,T threshold =T 0 threshold ±0.09T 0 threshold , T threshold = T 0 threshold ±0.08T 0 threshold , T threshold =T 0 threshold ±0.07T 0 threshold , T threshold =T 0 threshold ±0.06T 0 threshold , T threshold =T 0 t hreshold ±0.05T 0 threshold , T threshold =T 0 th reshold ±0.04T 0 threshold , T threshold =T 0 thr eshold ±0.03T 0 threshold , T threshold =T 0thre shold ±0.02T 0 threshold , or T threshold =T 0 thr eshold ±0.01T 0 threshold may vary within the range specified in

[0116] As described herein, T threshold By using electrodes thicker than the value Thus, for example, good or acceptable thickness for SAW resonators having piezoelectric plates thicker than 2λ Frequency response performance can be obtained. If the material is listed in Table 2, the corresponding T th reshold The value, for example, T threshold Electrodes having a thickness greater than . If a material is not listed in Table 2, the corresponding T th reshold The value can be calculated according to Equation 1 or Equation 2, for example T thresh old A threshold value can be used to design electrodes with thicknesses greater than .

[0117] In some embodiments, an electrode having one or more of the features described herein comprises a plurality of For such electrodes, T threshold The value is calculated by using the average density of the alloy as the mass density ρ, as given by Eq. or according to Equation 2. Such a threshold value can be, for example, T threshol d This can be utilized to design electrodes having a thickness greater than .

[0118] In some embodiments, an electrode having one or more of the features described herein comprises a plurality of Such electrodes can be formed to include layers (e.g., multiple different materials). T threshold The value is calculated by using the average density of the layers as the mass density ρ. The threshold value can be calculated according to Equation 1 or Equation 2. Such a threshold value can be calculated, for example, as T thresh old This can be utilized to design electrodes having a thickness greater than .

[0119] 23 and 24, in some embodiments, for a given electrode material: The electrode is then placed in a position whose thickness corresponds to T threshold If the value is less than this, it can be considered a thin electrode. The thickness corresponds to T threshold If the thickness is larger than the value, it can be considered as a thick electrode. For purposes of description, such T threshold Values ​​are measured or calculated values ​​or models. It may be a delta, extrapolated or interpolated value.

[0120] Thus, in the example of FIG. 23, curve 194 and the area under that curve 194 represent each quality The area above curve 194 can be considered to represent a thin electrode relative to the mass density material, Each mass density material can be considered as a thick electrode. Similarly, in the example of FIG. The curve represented by Equation 1 or Equation 2 and the area under the curve are given for each mass density material. The area above the curve represents the thickness of the material for each mass density. It can be considered as a thin electrode.

[0121] In some embodiments, the piezoelectric layer (herein referred to as a piezoelectric plate, a piezoelectric film, or simply a piezoelectric body) The thickness of the piezoelectric element (often called piezo) is T piezoGreater than 1.01T p iezo Greater than 1.02T piezo Greater than 1.03T piezo twist Also large, 1.04T piezo Greater than 1.05T piezo Greater than 1 .10T piezo Larger than 1.20T piezo Larger than 1.30T pi ezo Larger than 1.40T piezo Greater than 1.50T piezo than Large or 2T piezo If it is larger than , it can be considered a thick piezoelectric layer.

[0122] In some embodiments, the electrode has a thickness of T threshold Greater than 1.01T threshold Greater than 1.02T threshold than Large, 1.03T threshold Greater than 1.04T threshold Yo Larger than 1.05T threshold Larger than 1.10T threshol d Larger than 1.20T threshold Larger than 1.30T thresh old Larger than 1.40T threshold Greater than 1.50T thre shold Greater than or equal to 2T threshold If the thickness is larger than It can be done.

[0123] The various specific examples provided herein are described in the context of several specific configurations of each SAW resonator. For example, the various examples described with reference to FIGS. This is based on an electrode with a magnetic resonance (MR) of 0.5, where MR=F, as shown in FIG. / (F+G), where F is the width of the electrode finger and G is the gap size between two electrode fingers.

[0124] At least the dimension F affects the size of the electrode and therefore its mass, so In some embodiments, one or more features of the present disclosure are based on a metallization ratio (MR). For example, the electrodes can be implemented with (MR) × T electrode =(one The desired mass (also referred to herein as mass loading) is given based on the relationship between the mass and the load. In such a configuration, as the mass ratio of the electrodes increases, the A reduction in thickness may be utilized.

[0125] In other examples, various electrode examples formed from materials such as metals and alloys are described. It will be understood that an electrode having one or more features of the present disclosure may be formed using one or more materials. The electrodes may be formed of multiple layers of more than one material. When the material is subjected to the above mentioned process, the effective mass density (or equivalent mass related parameter) based on the individual mass densities of the material is used. The above information can be used.

[0126] In yet another embodiment, the various embodiments described with reference to FIGS. 12-21 may be formed by mixing LT and quartz. It will be appreciated that one or more features of the present disclosure are based on a combination of a piezoelectric material and a plate. Other combinations with the substrate can also be used for implementation, for example the LT / crystal combination. Similar to the combination of LN and quartz substrates, a mass-loading electrode function was used. It is possible.

[0127] As can be seen, in the example of Figures 12 to 20 (combination of LT / quartz crystal and copper electrodes), The electrodes are (0°, 110°, 0°)LT / (0°, 132°45', 90°) quartz structure base The plate is formed by combining plates. Here, (φ, θ, ψ) are the Euler angles. Figure 2 For example 1 (LT / quartz crystal and aluminum electrode combination), the electrodes are also (0°, 110°,0°)LT / (0°,132°45',90°) crystal structure substrate combination It will be appreciated that other structures on the LT and / or quartz substrates may also be utilized. For example, the orientation angle can be set to (0±5°, 80~155°, 0±5°), (90±5° , 90±5°, 0~180°) and equivalent orientation angles for LT are used to obtain the desired The desired electromechanical coupling characteristics can be achieved.

[0128] When LN is used instead of LT in combination with quartz, different orientation angles are available. For example, the orientation angle (0±5°, 60~160°, 0±5°), (90±5°, 90±5°, 0~180°) and equivalent orientation angles for LN to obtain the desired The electromechanical coupling characteristics can be provided.

[0129] It will also be appreciated that in some embodiments, the orientation angle of the quartz substrate is The direction of propagation of the oscillator is tilted so that the power flow angle is not allowed to approach zero. For example, the following orientations can be used for a quartz substrate: That is, (0±5°,θ,35°±8°), (10°±5°,θ,42°±8° ), (20°±5°,θ,50°±8°), (0°±5°,θ,0°±5°), (10° ±5°,θ,0°±5°), (20°±5°,θ,0°±5°), (0°±5°,θ,9 0°±5°), (10°±5°,θ,90°±5°), (20°±5°,θ,90°±5 °), and (90°±5°, 90°±5°, ψ), where θ and ψ are , has a value in the range of 0° to 180°.

[0130] In some embodiments, a SAW resonator having one or more of the features described herein may be , may be implemented as a product, and such product may be included in other products. Examples of different products that can be used are described with reference to Figures 25 to 29.

[0131] FIG. 25 illustrates, in some embodiments, multiple units of SAW resonators arranged in an array. For example, the wafer 200 may be fabricated while the unit 100 of one array is in the wafer state. ', such units being coupled together through a number of process steps For example, in some embodiments, the process steps of FIGS. All of these units of an array are made of different layers (e.g., quartz layer 112 and LT layer 13). 0, 134) while being bonded together as a wafer. In an example, all of the process steps of FIGS. 9A-9E are performed when one such array of units , having different layers (e.g., handle layer 140, LT layers 130, 144, and quartz layer 112). This can be accomplished while the wafers are bonded together.

[0132] Upon completion of the above-mentioned process steps in wafer form, the array of units 100' The SAW resonator 100 can be singulated to provide a large number of SAW resonators 100. One of the resonators 100 is illustrated. In the example of FIG. 25, the individual SAW resonators 100 are It is shown to include an electrode 102 formed on a piezoelectric layer 104, such as a LT layer. And the piezoelectric layer can be configured as described herein to provide desired characteristics. It will be appreciated that in some embodiments, one or more reflectors and Other electrodes may also be provided.

[0133] FIG. 26 illustrates, in some embodiments, an SA having one or more features described herein. It will be shown that the W resonator 100 can be implemented as part of a packaged device 300. The packaged device receives and accommodates one or more components, including the SAW resonator 100. The semiconductor device may include a packaging substrate 302 configured to support the semiconductor device.

[0134] FIG. 27 illustrates, in some embodiments, the SAW resonator-based package device of FIG. 3 shows that the device 300 can be a packaged filter device 300. The device may be configured to provide a filtering function, such as an RF filtering function. 3 includes a packaging substrate 302 suitable for receiving and supporting the SAW resonator 100. obtain.

[0135] FIG. 28 illustrates some embodiments in which a radio frequency (RF) module 400 The RF filter assembly 406 may include the above-mentioned filter. W resonator-based filter 100, packaged filter 300, or any combination thereof In some embodiments, the RF module 400 of FIG. For example, an RF integrated circuit (RFIC) 404 and an antenna switch module (ASM ) 408. Such modules may also include, for example, In some embodiments, the above-mentioned Some or all of the components are mounted by a packaging substrate 402. It may be supported.

[0136] In some implementations, a device having one or more of the features described herein and / or The circuitry may be included in an RF device, such as a wireless device. Such a device and / or The circuitry may be implemented directly in the wireless device, in a modular form as described herein, or in any other form as described herein. In some embodiments, such wireless devices may be implemented in any combination. Examples of such devices include mobile phones, smartphones, and handheld devices with or without telephony capabilities. This may include wireless devices, wireless tablets, and the like.

[0137] FIG. 29 illustrates an example of a wireless device 500 having one or more advantageous features described herein. In the context of a module having one or more features described herein, such module The module is generally depicted by a dashed box 400, e.g., a front-end module (FE In such an example, one or more of the SAWs described herein may be implemented as a The filter may be included in an assembly of filters, such as a duplexer 526. .

[0138] Referring to FIG. 29, a number of power amplifiers (PAs) 520 transmit and receive corresponding RF signals. The transceiver 510 may receive an RF signal to be amplified and transmitted. The transceiver may be constructed and operated in a known manner to transmit and process received signals. 510 is shown interacting with the baseband subsystem 408. The service system 408 communicates appropriate data and / or voice signals to the user and the transceiver 51. The transceiver 510 is also configured to provide conversion between an RF signal suitable for the 100 MHz to 100 MHz frequency band. A power management component configured to manage power for operation of the wireless device 500. Such power management may also be in communication with the baseband subsystem 506. 08 and can also control the operation of module 400.

[0139] The baseband subsystem 508 processes the voice and audio signals provided to and received from the user. and / or a user interface 502 to facilitate various inputs and outputs of data. The baseband subsystem 508 also facilitates the operation of the wireless device. Store data and / or instructions to perform the operations and / or store information for the user The processor 502 is also connected to a memory 504 configured to

[0140] In the example wireless device 500, the outputs of the multiple PAs 520 are connected to corresponding duplexers. 526. Such amplified and filtered signal is then routed to the For transmission purposes, the signal is routed through an antenna switch 514 to an antenna 516. In some embodiments, a duplexer 526 allows a common antenna (e.g., 516) to be In FIG. 29, the transmission and reception operations are performed simultaneously using the The signal is routed to an "Rx" path (not shown), which may include, for example, a low noise amplifier (LNA). It is shown to be so.

[0141] Unless the context clearly requires otherwise, In this regard, the words "including," "comprises," and the like are used in an inclusive sense as opposed to an exclusive or exhaustive sense. In general, the term "including but not limited to" should be interpreted as meaning "including but not limited to" The term "coupled" as used herein means that two or more elements are directly connected or connected via one or more interconnects. In addition, the present application also notes that the present invention may be either connected via an inter-connect element or a When used herein, the terms "herein," "upper," "lower," and words of similar import shall mean the same things as used herein. This application is hereby incorporated by reference in its entirety and not to any particular portions thereof. Where permitted, terms in the above Detailed Description using singular or plural numbers shall The terms "or" and "if" refer to a list of two or more items. The term "or" means any of the items in a list, Covers all of the items in the list, and any combination of the items in the list. .

[0142] The above description of embodiments of the present invention is not intended to be exhaustive or to be construed as limiting the scope of the present invention. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Although the embodiments and examples have been described above for illustrative purposes, those skilled in the art will recognize that the present invention Various equivalent modifications are possible within the scope. For example, the processes or blocks may be arranged in a given order. While presented herein, alternative embodiments may perform routines having steps in a different order. can use a system having blocks, some processes or blocks being These processes or blocks may be deleted, moved, added, subdivided, combined and / or modified. Each of the blocks may be implemented in a variety of different ways. While these processes or blocks may be shown as being executed in a sequence, Alternatively, they may be performed in parallel, or at different times.

[0143] The teachings of the present invention provided herein may be used in conjunction with other systems, not necessarily the systems mentioned above. The elements and operations of the various embodiments described above may be implemented in further embodiments. They may be combined to give form.

[0144] While certain embodiments of the present invention have been described, it will be understood that these embodiments are presented by way of example only. and are not intended to limit the scope of the present disclosure. Indeed, The novel methods and systems may be embodied in a variety of other forms and may be implemented in any manner that is consistent with the teachings set forth herein. Various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit and scope of the present disclosure. The appended claims and their equivalents are intended to be construed as falling within the scope and spirit of the present disclosure. It is intended to cover such forms or modifications as may come within the scope of the present invention.

Claims

1. 1. A radio frequency filter comprising: an input node for receiving a signal; an output node providing the filtered signal; a surface acoustic wave device mounted so as to be electrically present between the input node and the output node; Including, The surface acoustic wave device is configured to provide resonance of a surface acoustic wave having a wavelength λ, and includes a quartz substrate and a LiTaO ３ Or LiNbO ３ and a piezoelectric plate disposed on the quartz substrate, the piezoelectric plate has a thickness greater than 2λ; The surface acoustic wave device further includes an interdigital transducer electrode formed on the piezoelectric plate; The interdigital transducer electrodes have a combination of mass density ρ and thickness of 1.50 g / cm ３ <ρ≦6.00g / cm ３ and a mass density ρ in the range of 0.148λ and a thickness greater than 6.00 g / cm ３ <ρ≦12.0g / cm ３ and a mass density ρ in the range of 0.079 λ and a thickness greater than 12.0 g / cm ３ <ρ≦23.0g / cm ３ and a thickness greater than 0.036λ.

2. 1. A method for manufacturing a surface acoustic wave device that provides resonance of a surface acoustic wave having a wavelength λ, comprising the steps of: Providing or providing a quartz substrate; On the quartz substrate, LiTaO ３ Or LiNbO ３ mounting the piezoelectric plate formed from the above so that the quartz crystal substrate has a thickness greater than 2λ; forming an interdigital transducer electrode on said piezoelectric plate; Including, The interdigital transducer electrodes have a mass density ρ, and [0010] and has a thickness T greater than The quantity MR is the metallization ratio of the interdigital transducer electrodes, and the quantity a is 0.19091λ±δ ａ and the quantity b has a value of 0.17658λ±δ ｂ and the quantity c is 9.08282 g / cm ３ ±δ ｃ The method has a value of

3. mounting the piezoelectric plate includes forming or providing an assembly of a thick piezoelectric plate having a thickness greater than a thickness of the piezoelectric plate and a quartz plate; The method of claim 2 , wherein the quartz plate provides a quartz substrate for the piezoelectric plate.

4. mounting the piezoelectric plate further includes performing a thinning process on the thick piezoelectric plate to provide a piezoelectric plate having a thickness greater than 2λ; The method of claim 3 , wherein the piezoelectric plate includes a first surface that engages the quartz plate and a second surface opposite the first surface that results from the thinning process.

5. The method of claim 4 , wherein the thinning process comprises a polishing process.

6. The method of claim 4 , wherein forming the interdigital transducer electrodes on the piezoelectric plate includes forming the interdigital transducer electrodes on the second surface of the piezoelectric plate.

7. The method of claim 4 , wherein the quartz plate of the assembly is substantially the same as the quartz substrate.

8. The method of claim 2 , wherein mounting the piezoelectric plate comprises forming or providing an assembly of a thick piezoelectric plate having a thickness greater than a thickness of the piezoelectric plate and a handling substrate.

9. mounting the piezoelectric plate further includes performing a thinning process on the thick piezoelectric plate to provide a thinned piezoelectric plate having a thickness greater than 2λ; The method of claim 8 , wherein the thinned piezoelectric plate includes a first surface resulting from the thinning process and a second surface opposite the first surface that engages the handling substrate.

10. The method of claim 9 , wherein the thinning process comprises a polishing process.

11. 10. The method of claim 9, wherein mounting the piezoelectric plate further comprises attaching a quartz plate to the first surface of the thinned piezoelectric plate such that the quartz plate provides the quartz substrate.

12. Mounting the piezoelectric plate further includes removing the handling substrate to expose the second surface of the thinned piezoelectric plate; The method of claim 11 , wherein the thinned piezoelectric plate with the second surface exposed provides the piezoelectric plate.

13. The method of claim 12 , wherein removing the handle substrate comprises an etching process.

14. The method of claim 12 , wherein forming the interdigital transducer electrodes on the piezoelectric plate includes forming the interdigital transducer electrodes on the exposed second surface of the piezoelectric plate.

15. The method of claim 12 , wherein the quartz plate attached to the first surface of the piezoelectric plate is substantially the same as the quartz substrate.

16. 1. A radio frequency filter comprising: an input node for receiving a signal; an output node providing the filtered signal; a surface acoustic wave device mounted so as to be electrically present between the input node and the output node; Including, The surface acoustic wave device is configured to provide resonance of a surface acoustic wave having a wavelength λ, and includes a quartz substrate and a LiTaO ３ Or LiNbO ３ and a piezoelectric plate disposed on the quartz substrate, the piezoelectric plate has a thickness greater than 2λ; The surface acoustic wave device further includes an interdigital transducer electrode formed on the piezoelectric plate; The interdigital transducer electrodes have a mass density ρ, and [0025] and has a thickness T greater than The quantity MR is the metallization ratio of the interdigital transducer electrodes, and the quantity a is 0.19091λ±δ ａ and the quantity b has a value of 0.17658λ±δ ｂ and the quantity c is 9.08282 g / cm ３ ±δ ｃ A radio frequency filter having a value of

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