Multi-layer piezoelectric substrate

Abstract

An acoustic wave device, comprising: a stacked substrate having a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; external bonding pads disposed on the second material layer; and conductive vias passing through the stacked substrate and providing electrical contact between the contact pads and the external bonding pads.

Description

Technical Field

[0001] Embodiments of the present application relate to acoustic wave devices and heat dissipation structures for such acoustic wave devices. Background Art

[0002] Acoustic wave devices such as surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices can be used as components of filters in radio frequency electronic systems. For example, filters in the radio frequency front end of a mobile phone can include acoustic wave filters. Two acoustic wave filters can be arranged as a duplexer. Summary of the Invention

[0003] According to one aspect of the present application, an acoustic wave device is provided. The acoustic wave device includes: a stacked substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; external bonding pads disposed on the second material layer; and conductive vias passing through the stacked substrate and providing electrical contact between the contact pads and the external bonding pads.

[0004] In some embodiments, the second material layer includes a dielectric material. The second material layer may include spinel. The second material layer may include silicon.

[0005] In some embodiments, the acoustic wave device further includes a cavity defined above the interdigital transducer electrodes by a wall and a cap including a dielectric material.

[0006] In some embodiments, the acoustic wave device further includes a bonding layer bonding the piezoelectric material layer to the second material layer. The bonding layer may include silicon dioxide.

[0007] In some embodiments, the second material layer has a thickness between about 50 μm and about 150 μm.

[0008] In some embodiments, the piezoelectric material layer has a thickness between about 0.3 μm and about 20 μm.

[0009] In some embodiments, the acoustic wave device is configured as a surface acoustic wave resonator.

[0010] In some embodiments, the radio frequency filter includes a surface acoustic wave resonator. The electronic module may include the radio frequency filter. The electronic device may include the electronic module.

[0011] According to another aspect, a radio frequency filter is provided. The radio frequency filter includes at least one acoustic wave device. The at least one acoustic wave device includes: a laminated substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; external bonding pads disposed on the second material layer; and conductive vias passing through the laminated substrate and providing electrical contact between the contact pads and the external bonding pads.

[0012] According to another aspect, an electronic module is provided. The electronic module includes at least one radio frequency filter including at least one acoustic wave device. The at least one acoustic wave device includes: a laminated substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; external bonding pads disposed on the second material layer; and conductive vias passing through the laminated substrate and providing electrical contact between the contact pads and the external bonding pads.

[0013] According to another aspect, an acoustic wave device is provided. The acoustic wave device includes: a laminated substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; a cavity defined above the interdigital transducer electrodes by a wall and a cap including a dielectric material; external bonding pads disposed on the cap, away from the cavity on an opposite side of the cap; and conductive vias passing through the cap and providing electrical contact between the contact pads and the external bonding pads. Description of the Drawings

[0014] Embodiments of the present application will now be described by way of non-limiting examples with reference to the accompanying drawings.

[0015] Figure 1A is a simplified plan view of an example of a surface acoustic wave resonator;

[0016] Figure 1B is a simplified plan view of another example of a surface acoustic wave resonator;

[0017] Figure 1C is a simplified plan view of another example of a surface acoustic wave resonator;

[0018] Figure 2is a cross-sectional view of an embodiment of an encapsulated surface acoustic wave device;

[0019] Figure 3 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0020] Figure 4 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0021] Figure 5 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0022] Figure 6 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0023] Figure 7 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0024] Figure 8 is a cross-sectional view of another embodiment of an encapsulated surface acoustic wave device;

[0025] Figure 9 is a cross-sectional view of an example of a multilayer piezoelectric substrate;

[0026] Figure 10 is a block diagram of an example of a filter module that includes one or more surface acoustic wave elements according to various aspects of the present application;

[0027] Figure 11 is a block diagram of an example of a front-end module that may include one or more surface acoustic wave filter modules according to various aspects of the present application;

[0028] Figure 12 is a block diagram of an example of a wireless device that includes Figure 11 the front-end module;

[0029] Figure 13A illustrates details of an analog-encapsulated surface acoustic wave device for generating an analog of heat dissipation from the device;

[0030] Figure 13B illustrates Figure 13A other details of the analog-encapsulated surface acoustic wave device;

[0031] Figure 13C illustrates Figure 13A other details of the analog-encapsulated surface acoustic wave device;

[0032] Figure 14A illustrates details of another analog-encapsulated surface acoustic wave device for generating an analog of heat dissipation from the device;

[0033] Figure 14B illustrates Figure 14A other details of the surface acoustic wave device in the simulated package; and

[0034] Figure 14C illustrates Figure 14A other details of the surface acoustic wave device in the simulated package. DETAILED DESCRIPTION

[0035] The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be implemented in many different ways, e.g., as defined and covered by the claims. In this specification, reference is made to the accompanying drawings, in which like reference numerals may represent like or functionally similar elements. It should be understood that the elements shown in the figures are not necessarily drawn to scale. Further, it should be understood that some embodiments may include more elements than those shown in the figures and / or a subset of the elements shown in the figures. Additionally, some embodiments may incorporate any suitable combination of features from two or more of the figures.

[0036] Figure 1A is a plan view of a surface acoustic wave (SAW) resonator 10 such as may be used in a SAW filter, duplexer, balun, etc.

[0037] The acoustic resonator 10 is formed on a piezoelectric substrate such as a lithium tantalate (LiTaO3) or lithium niobate (LiNbO3) substrate 12 and includes interdigital transducer (IDT) electrodes 14 and reflector electrodes 16. In use, the IDT electrodes 14 excite a primary acoustic wave having a wavelength λ along the surface of the piezoelectric substrate 12. The reflector electrodes 16 sandwich the IDT electrodes 14 therebetween and reflect the primary acoustic wave back and forth through the IDT electrodes 14. The primary acoustic wave of the device propagates perpendicular to the length direction of the IDT electrodes.

[0038] The IDT electrodes 14 include a first bus bar electrode 18A and a second bus bar electrode 18B facing the first bus bar electrode 18A. The bus bar electrodes 18A, 18B may herein be referred to as and are labeled in the figures as bus bar electrodes 18. The IDT electrodes 14 further include first electrode fingers 20A extending from the first bus bar electrode 18A towards the second bus bar electrode 18B and second electrode fingers 20B extending from the second bus bar electrode 18B towards the first bus bar electrode 18A.

[0039] Each of the reflector electrodes 16 (also referred to as reflector gratings) includes a first reflector bus bar electrode 24A and a second reflector bus bar electrode 24B (collectively referred to herein as reflector bus bar electrodes 24) and reflector fingers 26 extending therebetween and electrically coupling the first bus bar electrode 24A and the second bus bar electrode 24B.

[0040] In other embodiments disclosed herein, such as Figure 1B illustrated, the reflector bus bars electrodes 24A, 24B may be omitted, and the reflector fingers 26 may be electrically unconnected. Further, as Figure 1C illustrated, the acoustic wave resonators disclosed herein may include dummy electrode fingers 20C aligned with respective electrode fingers 20A, 20B. Each dummy electrode finger 20C extends from the opposite bus bar electrodes 18A, 18B as compared to its respective aligned electrode finger 20A, 20B.

[0041] It should be understood that Figure 1A - Figure 1C the acoustic wave resonator 10 illustrated therein and other circuit elements illustrated in other figures presented herein are illustrated in a highly simplified form. The relative dimensions of the different features are not shown to scale. Further, a typical acoustic wave resonator generally includes a much greater number of electrode fingers and reflector fingers than illustrated. A typical acoustic wave resonator or filter element may also include a plurality of IDT electrodes sandwiched between the reflector electrodes.

[0042] The operating parameters of SAW devices typically vary with temperature. For example, in a radio frequency filter formed by a SAW resonator, both the resonant and anti-resonant frequencies of the filter may decrease with temperature. The temperature dependence of the parameters of SAW devices is undesirable because one generally desires a device that operates consistently under different operating conditions. Thus, it may be desirable to remove heat generated in a working SAW device as quickly and efficiently as possible so that the device does not heat up to a temperature at which the operating parameters of the device shift by more than an acceptable amount.

[0043] Figure 2 One method of encapsulating a SAW device is illustrated therein. A cavity 26 is defined in a portion of a substrate 12, and the IDT electrode 14 (and reflector electrodes not shown separately) is disposed on the portion through a cap layer of a dielectric material 28 and a plurality of sidewalls (such as polyimide). Conductive vias 30 are formed through the cap layer of the dielectric material and are electrically connected to contact pads 32 on the substrate 12 that are in electrical communication with the IDT electrode 14. The conductive vias 30 provide electrical communication between the contact pads 32 and external bond pads 34, which may be used to electrically connect the encapsulated SAW device to, for example, a circuit board. The conductive vias and the external bond pads may be formed of a highly conductive and thermally conductive material such as copper. The side of the substrate 12 on which the IDT electrode 14 is disposed is arranged face down such that the side of the substrate 12 including the IDT electrode 14 faces the external bond pads 34.

[0044] When mounted to a circuit board or other external substrate, one path for heat to leave the encapsulated SAW device is through the external bond pads, such as Figure 3The bonding pad 34 illustrated therein and enters a circuit board or other external substrate. In order for heat to conduct out of the packaged device, the heat generated in the portion of the device that is not in direct contact with the bonding pad 34 must propagate through other parts of the device. Compared with other materials (such as metals), the piezoelectric material (such as LiTaO3) that can form the substrate 12 generally has a lower thermal conductivity. As Figure 2 The illustrated packaged SAW device can conduct heat out of the device, and conducting heat through the bonding pad 34 and the substrate 12 may not be as fast as desired.

[0045] A method for increasing the heat conduction rate and efficiency of a packaged SAW device as illustrated in Figure 2 involves increasing the thermal conductivity of the substrate 12. The thermal conductivity of the substrate can be increased by removing a portion of the piezoelectric material of the substrate 12 and replacing it with a layer of dielectric material 12' having a higher thermal conductivity, such as Figure 3 spinel (MgAl2O4) illustrated in or silicon (Si) as illustrated in Figure 4 shown. Other materials, such as sapphire, aluminum nitride, silicon dioxide, or diamond can be used additionally or alternatively for the material layer 12'. The material layer 12' can be bonded to the piezoelectric material of the substrate 12 using, for example, a silicon dioxide (SiO2) layer or other suitable bonding material. The bonding layer is illustrated as layer 22 in Figure 8 The thickness of the piezoelectric material layer should be maintained at a thickness sufficient for the SAW device to function properly, for example, between about 0.3 μm and about 50 μm or greater than twice the wavelength λ of the main acoustic wave excited by the IDT electrodes of the SAW device. The thickness of the material layer 12' can be between about 50 μm and about 300 μm. The layer bonding the piezoelectric material of the substrate 12 to the material layer 12' can be, for example, a thickness between about 0.1 μm and about 50 μm.

[0046] A comparison of the thermal conductivities of various materials that can be used in embodiments of a packaged SAW device is provided in Table 1 below:

[0047] Table 1: Comparison of Thermal Conductivities of Selected Materials

[0048] Material Thermal Conductivity (W / mK) Lithium Tantalate 2.93 Polyimide 3.1 <![CDATA[Spinel (MgAl2O4)]]> 16.2 Silicon 140 Copper 402

[0049] In Figure 5 an alternative arrangement for a packaged SAW device is illustrated. Figure 5 The packaged SAW device of Figure 2 differs in that the surface of the substrate 12 on which the IDT electrodes 14 are formed faces away from the external bonding pad 34 and is formed, and the conductive vias 30 pass through the substrate 12 rather than through the dielectric material 28 forming the cap covering the cavity in which the IDT electrodes 14 are disposed. Figure 5The embodiments show problems related to heat dissipation similar to those of Figure 3 . Heat generated in portions of the packaged device that do not directly contact the conductive vias 30 must be propagated, for example, mainly through the low thermal conductivity substrate 12 to the conductive vias for export from the package. Compared with the SAW device packages of Figure 2 , the conductive vias 30 of the embodiments of Figure 5 can have a larger surface area in contact with the material of the substrate 12 and can thus conduct heat out of the substrate 12 and into the circuit board or other external substrate more efficiently. However, this increase in heat transfer efficiency may only be slight and smaller than desired.

[0050] In a manner similar to the embodiments of Figure 3 and Figure 4 , a portion of the piezoelectric substrate 12 can be removed and replaced with a dielectric material layer 12” having a higher thermal conductivity than the piezoelectric material. The material layer 12” can include spinel ( Figure 6 ) or silicon ( Figure 7 ), such as a SiO2 layer, bonded to the piezoelectric material. Other materials, such as sapphire, aluminum nitride, silicon dioxide, or diamond, can be additionally or alternatively used for the material layer 12”. The conductive vias 30 pass through both the piezoelectric material portion 12 of the substrate and the material layer 12”. External bonding pads 34 can be provided on the opposite (bottom) side of the material layer 12” that is the piezoelectric material layer 12. Figure 6 and Figure 7 . The thickness of the piezoelectric material layer and the thickness of the bonding layer in the embodiments of Figure 3 and Figure 4 can be the same or similar to this thickness in the embodiments of Figure 3 and Figure 4 . Figure 6 and Figure 7 . The thickness of the material layer 12” in can be less than the thickness of the material layer 12' in Figure 3 and Figure 4 . For example, the thickness of the material layer 12” in the embodiments of Figure 6 and Figure 7 can be between about 50 μm and about 300 μm.

[0051] As shown in Figure 2 - Figure 8 , the substrate 12 of the acoustic wave device disclosed herein can include a single layer of a single piezoelectric material such as LiTaO3 or LiNbO3. However, it should be understood that in some embodiments, the substrate 12 of any acoustic wave device disclosed herein can be a multilayer piezoelectric substrate (MPS). As shown in Figure 9In the above, the MPS substrate may include a body having at least one or two or more (e.g., three or more) thin film piezoelectric material layers 12A, 12B, 12C. Different layers 12A, 12B, 12C may exhibit at least two different electromechanical coupling coefficients. The intermediate layer 12B may have the largest electromechanical coupling coefficient among the layers 12A, 12B, 12C. Such an arrangement may concentrate the energy of surface acoustic waves on the surface of the MPS, such that the overall electromechanical coupling coefficient of the MPS is greater than the electromechanical coupling coefficient of each individual piezoelectric material layer. Materials suitable for the different piezoelectric material layers 12A, 12B, 12C may include, for example, ZnO, LiNbO3, LiTaO3, Pb[Zr x Ti 1-x O3 (PZT), PbTiO3, BaTiO3, or Li2B4O7. In some embodiments, a single layer of the layers 12A, 12B, 12C or two layers of the layers 12A, 12B, 12C may include or be composed of a piezoelectric material, and the remaining layers of the layers 12A, 12B, 12C may include or be composed of a non-piezoelectric material such as a dielectric material.

[0052] The acoustic wave devices discussed herein may be implemented in various packaged modules. Some example packaged modules will now be discussed, in which any suitable principles and advantages of the packaged acoustic wave devices discussed herein may be realized. Figure 10 、 Figure 11 and Figure 12 are schematic block diagrams of illustrative packaged modules and devices according to certain embodiments.

[0053] As described above, embodiments of surface acoustic wave elements may be configured as, for example, filters or for use in filters. In turn, surface acoustic wave (SAW) filters using one or more surface acoustic wave elements may be incorporated and packaged into modules that can ultimately be used in, for example, electronic devices such as wireless communication devices. Figure 10FIG. 0 is a block diagram illustrating an example of a module 300 that includes a SAW filter 310. The SAW filter 310 may be implemented on one or more wafers 320 that include one or more connection pads 322. For example, the SAW filter 310 may include a connection pad 322 corresponding to an input contact of the SAW filter and another connection pad 322 corresponding to an output contact of the SAW filter. The packaged module 300 includes a package substrate 330 that is configured to receive a plurality of components including the wafer 320. A plurality of connection pads 332 may be provided on the package substrate 330, and various connection pads 322 of the SAW filter wafer 320 may be connected to the connection pads 332 on the package substrate 330 via an electrical connector 334, which may be, for example, a solder bump or a wirebond, to allow various signals to be transmitted to and from the SAW filter 310. The module 300 may optionally further include other circuit wafers 340, such as one or more additional filters, amplifiers, pre-filters, modulators, demodulators, down-converters, etc. as would be known to those skilled in the art of semiconductor manufacturing in view of the present disclosure. In some embodiments, the module 300 may further include one or more packaging structures to, for example, provide protection and facilitate handling of the module 300. Such a packaging structure may include a molded encapsulation formed on the package substrate 330 and sized to substantially enclose the various circuits and components thereon.

[0054] Various examples and embodiments of the SAW filter 310 may be used in a wide variety of electronic devices. For example, the SAW filter 310 may be used in an antenna duplexer, which itself may be incorporated into various electronic devices such as RF front-end modules and communication devices.

[0055] Reference Figure 11 FIG. 8 is a block diagram illustrating an example of a front-end module 400 that may be used in an electronic device such as a wireless communication device (e.g., a mobile phone). The front-end module 400 includes an antenna duplexer 410 having a common node 402, an input node 404, and an output node 406. An antenna 510 is connected to the common node 402.

[0056] The antenna duplexer 410 may include one or more transmit filters 412 connected between the input node 404 and the common node 402, and one or more receive filters 414 connected between the common node 402 and the output node 406. The (one or more) passbands of the (one or more) transmit filters are different from the (one or more) passbands of the receive filters. Examples of SAW filters 310 may be used to form the (one or more) transmit filters 412 and / or the (one or more) receive filters 414. An inductor or other matching component 420 may be connected at the common node 402.

[0057] The front-end module 400 further includes a transmitter circuit 432 connected to the input node 404 of the duplexer 410 and a receiver circuit 434 connected to the output node 406 of the duplexer 410. The transmitter circuit 432 may generate a signal for transmission via the antenna, and the receiver circuit 434 may receive and process the signal received via the antenna 510. In some embodiments, as Figure 11 shown, the receiver and transmitter circuits are implemented as separate components. However, in other embodiments, these components may be integrated into a common transceiver circuit or module. As will be understood by those skilled in the art, the front-end module 400 may include Figure 11 other components not shown, including but not limited to switches, electromagnetic couplers, amplifiers, processors, etc.

[0058] Figure 12 is a block diagram of an example of a wireless device 500, which includes Figure 11 the antenna duplexer 410 shown therein. The wireless device 500 may be a cellular phone, a smart phone, a tablet computer, a modem, a communication network, or any other portable or non-portable device configured for voice or data communication. The wireless device 500 may receive and transmit signals from and to the antenna 510. The wireless device includes an embodiment similar to the front-end module 400 discussed above with reference to Figure 11 . As described above, the front-end module 400 includes the duplexer 410. In the Figure 12 example shown, the front-end module 400 further includes an antenna switch 440, which may be configured to switch between different frequency bands or modes such as transmit and receive modes. In the Figure 12 example shown, the antenna switch 440 is located between the duplexer 410 and the antenna 510; however, in other examples, the duplexer 410 may be located between the antenna switch 440 and the antenna 510. In other examples, the antenna switch 440 and the duplexer 410 may be integrated into a single component.

[0059] The front-end module 400 includes a transceiver 430, which is configured to generate a signal for transmission or process the received signal. As Figure 10As shown in the example of, the transceiver 430 may include a transmitter circuit 432 connectable to the input node 404 of the duplexer 410 and a receiver circuit 434 connectable to the output node 406 of the duplexer 410.

[0060] The signal generated for transmission by the transmitter circuit 432 is received by a power amplifier (PA) module 450, which amplifies the generated signal from the transceiver 430. The power amplifier module 450 may include one or more power amplifiers. The power amplifier module 450 can be used to amplify transmission signals in various RF or other frequency bands. For example, the power amplifier module 450 may receive an enable signal that can be used to pulse the output of the power amplifier to assist in transmitting a wireless local area network (WLAN) signal or any other suitable pulsed signal. The power amplifier module 450 may be configured to amplify any one of various types of signals, including, for example, Global System for Mobile (GSM) signals, code division multiple access (CDMA) signals, W-CDMA signals, Long-Term Evolution (LTE) signals, or EDGE signals. In certain embodiments, the power amplifier module 450 and associated components including switches, etc., may be fabricated using, for example, high-electron-mobility transistors (pHEMTs) or insulated-gate bipolar transistors (BiFETs) on a gallium arsenide (GaAs) substrate, or using complementary metal-oxide semiconductor (CMOS) field-effect transistors on a silicon substrate.

[0061] Still referring to Figure 12 , the front-end module 400 may further include a low-noise amplifier module 460 that amplifies the received signal from the antenna 510 and provides the amplified signal to the receiver circuit 434 of the transceiver 430.

[0062] Figure 12The wireless device 500 includes a power management subsystem 520 that is connected to the transceiver 430 and manages the power for the operation of the wireless device 500. The power management system 520 may also control the operation of the baseband subsystem 530 and various other components of the wireless device 500. The power management system 520 may include or be connected to a battery (not shown) that powers the various components of the wireless device 500. The power management system 520 may also include, for example, one or more processors or controllers that can control signal transmission. In one embodiment, the baseband subsystem 530 is connected to the user interface 540 to facilitate various inputs and outputs of voice and / or data provided to and received from the user. The baseband subsystem 530 may also be connected to the memory 550, which is configured to store data and / or instructions to facilitate the operation of the wireless device and / or to provide storage of information for the user. Any of the above embodiments may be implemented in association with a mobile device such as a cellular phone. The principles and advantages of the embodiments may be used in any system or device that can benefit from any of the embodiments described herein, such as any uplink wireless communication device. The teachings herein are applicable to various systems. Although this application includes some example embodiments, the teachings described herein may be applied to various architectures. Any of the principles and advantages discussed herein may be implemented in association with an RF circuit that is configured to process signals in the range from approximately 30 kHz to 5 GHz, such as signals in the range from approximately 600 MHz to 2.7 GHz.

[0063] Aspects of the present application may be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronic products, such as components of consumer electronic products such as packaged RF modules, uplink wireless communication devices, wireless communication infrastructure, electronic test equipment, etc. Examples of electronic devices may include, but are not limited to, mobile phones such as smart phones, wearable computing devices such as smart watches or earphones, telephones, televisions, computer monitors, computers, modems, laptops, notebooks, tablets, microwaves, refrigerators, in-vehicle electronic systems such as automotive electronic systems, stereo systems, digital music players, radios, cameras such as digital cameras, portable memory chips, washing machines, dryers, washer / dryers, copiers, fax machines, scanners, multifunction peripherals, wristwatches, clocks, etc. Additionally, the electronic device may include unfinished products.

[0064] Example:

[0065] Simulations were conducted to determine the junction thermal resistance R from the IDT electrode 14 to the external bond pad 34 in each of the embodiments illustrated in Figure 2 - Figure 7 . The simulations were performed using a simulated device including the materials and dimensions shown in Figure 13A - Figure 13C for the embodiments of Figure 2 - Figure 4 . The simulations were performed using a simulated device including the materials and dimensions shown in Figure 14A - Figure 14CThe simulation device with the materials and dimensions shown performs Figure 5 - Figure 7 the simulation of the embodiment. The results of the simulation are as follows:

[0066] Table 2: Results of Thermal Resistance Simulation

[0067] Example Junction Thermal Resistance (°C / W) Figure 2 (Flip-chip lithium tantalate substrate) 108 Figure 3 (Flip Chip Lithium Tantalate and Spinel Stacked Substrate) 34 Figure 4 (Flip-chip lithium tantalate and silicon stacked substrate) 12.6 Figure 5 (Lithium tantalate substrate) 84 Figure 6 (Lithium tantalate and spinel laminated substrate) 22.3 Figure 7 (Lithium tantalate and silicon laminated substrate) 6.3

[0068] These results show that, compared with the corresponding packaged SAW device of Figure 2 - Figure 4 , the packaged SAW device as shown in Figure 5 - Figure 7 has a more desirable (lower) junction thermal resistance. The junction thermal resistance decreases as the thermal conductivity of the material or materials of the substrate on which the packaged device is formed increases.

[0069] It should be understood that Figure 13A - 13C and Figure 14A - 14C the size and characteristics of the simulation device can be used for devices having an operating frequency between 600 MHz and 3.7 GHz. For the size and characteristics of devices operating at other frequencies, for example, the number of contacts, the thickness of the silicon or spinel or piezoelectric material layer, the number or arrangement of electrode fingers, etc. may be different from those shown herein.

[0070] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise", "comprises", "include", "includes", etc. shall be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to". As commonly used herein, the word "coupled" means two or more elements that can be directly connected or connected through one or more connections. Similarly, as commonly used herein, the word "connected" means two or more elements that can be directly connected or connected by means of one or more intermediate elements. Additionally, when used in this application, the words "herein", "above", "below" and words of similar import shall mean this application as a whole and not any particular part of this application. Where the context permits, the words in the above detailed description using the singular or plural may also respectively include the plural or singular. The word "or" refers to a list of two or more items, and the word encompasses all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0071] Moreover, unless otherwise expressly stated or otherwise understood within the context in which it is used, conditional language, such as "can", "could", "may", "might", "such as", "for example", "e.g.", "such that", and the like, used herein is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or states. Thus, such conditional language is generally not intended to imply that one or more embodiments require, in any way, any features, elements, and / or states, or that one or more embodiments must include logic for deciding, with or without author input or prompting, whether these features, elements, and / or states are included in or are to be performed in any particular embodiment.

[0072] Although certain embodiments have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the present application. Indeed, the novel devices, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the present application. For example, while blocks may be presented in a given arrangement, alternative embodiments may perform similar functions with different components and / or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above may be combined to provide further embodiments. The appended claims and their equivalents are intended to cover such forms or modifications that fall within the scope and spirit of the present application.

Claims

1. An acoustic wave device, comprising: A stacked substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; Interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; Contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; External bonding pads disposed on the second material layer and configured to electrically connect the acoustic wave device to a circuit board; And Conductive vias passing through the stacked substrate and providing electrical contact between the contact pads and the external bonding pads, each of the conductive vias passing straight through the stacked substrate from the contact pad to the external bonding pad, Wherein the piezoelectric material layer includes a multi-layer piezoelectric substrate, the multi-layer piezoelectric substrate includes three layers, and a central layer of the three layers has the largest electromechanical coupling coefficient among the three layers.

2. The acoustic wave device according to claim 1, wherein, The second material layer includes a dielectric material.

3. The acoustic wave device according to claim 2, wherein The second material layer includes spinel.

4. The acoustic wave device according to claim 2, wherein, The second material layer includes silicon.

5. The acoustic wave device according to claim 1, further comprising a bonding layer bonding the piezoelectric material layer to the second material layer.

6. The acoustic wave device according to claim 5, wherein, The bonding layer includes silicon dioxide.

7. The acoustic wave device according to claim 1, wherein, The second material layer has a thickness between about 50 μm and about 150 μm.

8. The acoustic wave device according to claim 1, wherein, Each of the conductive vias passes straight through the stacked substrate from the contact pad to the external bonding pad.

9. The acoustic wave device according to claim 1, wherein, The piezoelectric material layer has a thickness between about 0.3 μm and about 20 μm.

10. The acoustic wave device according to claim 1, configured as a surface acoustic wave resonator.

11. A radio frequency filter, comprising the surface acoustic wave resonator according to claim 10.

12. An electronic module, comprising the radio frequency filter according to claim 11.

13. An electronic device, comprising the electronic module according to claim 12.

14. A radio frequency filter, comprising: At least one acoustic wave device, the at least one acoustic wave device including: A stacked substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, the piezoelectric material layer including a multi-layer piezoelectric substrate, the multi-layer piezoelectric substrate includes three layers, and a central layer of the three layers has the largest electromechanical coupling coefficient among the three layers; Interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; Contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; External bonding pads disposed on the second material layer and configured to electrically connect the acoustic wave device to a circuit board; And Conductive vias passing through the stacked substrate and providing electrical contact between the contact pads and the external bonding pads.

15. An electronic module, comprising: At least one radio frequency filter, the at least one radio frequency filter including at least one acoustic wave device, the at least one acoustic wave device including: A stacked substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, the piezoelectric material layer including a multi-layer piezoelectric substrate, the multi-layer piezoelectric substrate including three layers, and a central layer of the three layers having the largest electromechanical coupling coefficient among the three layers; Interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; Contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; External bonding pads disposed on the second material layer and configured to electrically connect the acoustic wave device to a circuit board; And Conductive vias passing through the stacked substrate and providing electrical contact between the contact pads and the external bonding pads.

16. An acoustic wave device, comprising: A stacked substrate including a piezoelectric material layer bonded to a second material layer, the second material layer including a material having a higher thermal conductivity than the piezoelectric material layer; Interdigital transducer electrodes disposed on a surface of the piezoelectric material layer; A cavity defined above the interdigital transducer electrodes by a wall and a cap including a dielectric material; Contact pads disposed on the piezoelectric material layer within the cavity and in electrical contact with the interdigital transducer electrodes; External bonding pads disposed on the cap and spaced from the cavity on an opposite side of the cap; And Conductive vias passing through the cap and providing electrical contact between the contact pads and the external bonding pads, wherein the piezoelectric material layer includes a multi-layer piezoelectric substrate, the multi-layer piezoelectric substrate including three layers, and a central layer of the three layers having the largest electromechanical coupling coefficient among the three layers.

17. The acoustic wave device according to claim 16, wherein, Each of the conductive vias passes through the stacked substrate in a straight line from the contact pads to the external bonding pads.

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