MULTI-LAYER PIEZOELECTRIC SUBSTRATE

Abstract

High frequency filter, comprising: at least one acoustic wave device (10) comprising: a layered substrate having a piezoelectric material layer (12) comprising a multilayer piezoelectric substrate having three layers (12A, 12B, 12C) bonded to a second material layer (12'; 12") comprising a material having a higher thermal conductivity than the piezoelectric material layer (12), of which a central layer (12B) of the three layers (12A, 12B, 12C) has the largest electromechanical coupling coefficient; interdigital transducer electrodes (14) arranged on a surface of the piezoelectric material layer (12); Contact pads (32) arranged on the piezoelectric material layer (12) and in electrical contact with the interdigital transducer electrodes (14); external connection pads (34) arranged on the second material layer (12'; 12"); and conductive vias (30) passing through the layered substrate (12; 12'; 12'; 12") and establishing electrical contact between the contact pads (32) and external connection pads (34).

Description

BACKGROUNDTechnical field

[0001] The present invention relates to acoustic wave devices and heat dissipation structures therefor, a high frequency filter and an electronic module. Description of related technology

[0002] Acoustic wave devices, such as surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices, can be used as components of filters in high-frequency electronic systems. For example, filters in a mobile phone's high-frequency front end can incorporate acoustic wave filters. Two acoustic wave filters can be arranged as a duplexer.

[0003] DE 11 2016 002 825 T5 describes an elastic wave filter device. In the elastic wave filter device, IDT electrodes and first and second electrode terminal regions are provided on a first main surface of a piezoelectric substrate. The piezoelectric substrate, a support layer, and a cover member form a hollow portion. A signal terminal, a ground terminal, and a heat diffusion layer are arranged on a second main surface of the piezoelectric substrate. The first and second electrode terminal regions are electrically connected to the signal terminal and the ground terminal, respectively, by first and second connecting electrodes. The heat diffusion layer is arranged at a position where the heat diffusion layer overlaps at least a portion of the IDT electrodes and across the piezoelectric substrate.

[0004] US 2015 / 0028966 A1 describes an elastic wave filter device. It comprises an elastic wave filter chip for transmission and an elastic wave filter chip for reception. The elastic wave filter chip comprises an insulating support substrate, a piezoelectric layer supported directly or indirectly by the support substrate, and an IDT electrode in contact with the piezoelectric layer. The receiving elastic wave filter chip comprises a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate. The thermal conductivity of the support substrate is higher than the thermal conductivity of the piezoelectric layer and the piezoelectric substrate.

[0005] US 2017 / 0214386 A1 describes a filter component with a passive element. The filter component comprises a filter substrate, an elastic wave filter having an elastic wave resonator in a predetermined region of one main surface of the filter substrate, and a support substrate on another main surface of the filter substrate. A passive element is provided in or on the support substrate, the passive element has a wiring electrode, and is electrically connected to the elastic wave filter. SUMMARY

[0006] The invention is defined in the independent patent claims. Advantageous developments of the invention are defined in the dependent patent claims.

[0007] According to one aspect of the present disclosure, an acoustic wave device is provided.The acoustic wave device comprises a layered substrate having a piezoelectric material layer including a multilayer piezoelectric substrate having three layers bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, of which a central layer of the three layers has the largest electromechanical coupling coefficient, interdigital transducer electrodes arranged on a surface of the piezoelectric material layer, contact pads arranged on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes, external connection pads arranged on the second material layer, and conductive vias passing through the layered substrate and establishing electrical contact between the contact pads and external connection pads.

[0008] 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.

[0009] In some embodiments, the acoustic wave device further comprises a cavity defined by walls above the interdigital transducer electrodes and a cap comprising a dielectric material.

[0010] In some embodiments, the acoustic wave device further comprises a bonding layer that bonds the piezoelectric material layer to the second material layer. The bonding layer may comprise silicon dioxide.

[0011] In some embodiments, the second material layer has a thickness between about 50 µm and about 150 µm.

[0012] In some embodiments, the piezoelectric material layer has a thickness between about 0.3 µm and about 20 µm.

[0013] In some embodiments, the acoustic wave device is configured as a surface acoustic wave resonator.

[0014] In some embodiments, a high-frequency filter includes the surface acoustic wave resonator. An electronic module may include the high-frequency filter. An electronic device may include the electronic module.

[0015] According to another aspect, a high-frequency filter is provided. The high-frequency filter comprises at least one acoustic wave device. The at least one acoustic wave device includes a layered substrate comprising a multilayer piezoelectric substrate with three layers of piezoelectric material bonded to a second material layer comprising a material with a higher thermal conductivity than the piezoelectric material layer, a central layer of the three layers having the largest electromechanical coupling coefficient; 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 connection pads disposed on the second material layer;and conductive vias that pass through the layered substrate and establish electrical contact between the contact pads and external connection pads.

[0016] According to a further aspect, an electronic module is provided. The electronic module comprises at least one high-frequency filter with at least one acoustic wave device.The at least one acoustic wave device includes a layered substrate having a piezoelectric material layer including a multilayer piezoelectric substrate having three layers bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, of which a central layer of the three layers has the largest electromechanical coupling coefficient, interdigital transducer electrodes arranged on a surface of the piezoelectric material layer, contact pads arranged on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes, external connection pads arranged on the second material layer, and conductive vias passing through the layered substrate and establishing electrical contact between the contact pads and external connection pads.

[0017] According to another aspect, an acoustic wave device is provided. The acoustic wave device comprises a layered substrate with a piezoelectric material layer comprising a multilayer piezoelectric substrate with three layers bonded to a second material layer comprising a material with a higher thermal conductivity than the piezoelectric material layer, of which a central layer of the three layers has the largest electromechanical coupling coefficient; interdigital transducer electrodes arranged on a surface of the piezoelectric material layer; contact pads arranged on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes; a cavity defined above the interdigital transducer electrodes by walls and a cap with a dielectric contact; external connection pads;which are arranged on the cap on an opposite side of the cap from the cavity, and conductive vias which pass through the cap and establish electrical contact between the contact pads and external connection pads. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments of this disclosure will now be described by way of example with reference to the accompanying drawings. Fig. 1A is a simplified plan view of an example of a surface acoustic wave resonator; Fig. 1B is a simplified plan view of another example of a surface acoustic wave resonator; Fig. Figure 1C is a simplified plan view of another example of a surface acoustic wave resonator; Fig. 2 is a cross-sectional view of one embodiment of a packaged surface acoustic wave device; Fig. 3 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 4 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 5 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 6 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 7 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 8 is a cross-sectional view of another embodiment of a packaged surface acoustic wave device; Fig. 9 is a cross-sectional view of an example of a multilayer piezoelectric substrate; Fig. 10 is a block diagram of an example of a filter module that may include one or more surface acoustic wave elements according to aspects of the present disclosure; Fig. 11 is a block diagram of an example front-end module that may include one or more filter modules according to aspects of the present disclosure; Fig. 12 is a block diagram of an example of a wireless device with the front-end module of Fig. 11; Fig. Figure 13A illustrates details of a simulated surface acoustic wave device used to generate simulations of heat dissipation from the device; Fig. Figure 13B illustrates further details of the simulated surface acoustic wave device of Fig. 13A; Fig. Figure 13C illustrates further details of the simulated surface acoustic wave device of Fig. 13A; Fig. 14A illustrates details of another simulated surface acoustic wave device used to generate simulations of heat dissipation from the device; Fig. Figure 14B illustrates further details of the simulated packaged surface acoustic wave device of Fig. 14A; and Fig. Figure 14C illustrates further details of the simulated surface acoustic wave device of Fig. 14A. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0019] The following description of certain embodiments represents various descriptions of specific embodiments. However, the innovations described herein may be implemented in a variety of ways, for example, through the definition and coverage of the claims. Reference is made throughout this description to the drawings, where like reference numbers may indicate identical or functionally similar elements. It should be understood that elements shown in the figures are not necessarily drawn to scale. Furthermore, it is contemplated that certain embodiments may include more elements than shown in any one drawing and / or a subset of the elements shown in a drawing. Furthermore, some embodiments may include any suitable combination of features from two or more drawings.

[0020] Fig. 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.

[0021] The acoustic wave resonator 10 is formed on a piezoelectric substrate, for example, a lithium tantalate (LiTaO3) or lithium niobate (LiNbO3) substrate 12, and includes electrodes 14 for an interdigital transducer (IDT) and reflector electrodes 16. In use, the IDT electrodes 14 excite a main acoustic wave having a wavelength λ along a surface of the piezoelectric substrate 12. The reflector electrodes 16 surround the IDT electrodes 14 and reflect the main acoustic wave back and forth through the IDT electrodes 14. The main acoustic wave of the device travels perpendicular to the longitudinal direction of the IDT electrodes.

[0022] The IDT electrodes 14 include a first busbar electrode 18A and a second busbar electrode 18B opposite the first busbar electrode 18A. The busbar electrodes 18A, 18B may be referred to herein as busbar electrode 18 and are referred to as such in the figures. The IDT electrodes 14 further include first electrode fingers 20A extending from the first busbar electrode 18A toward the second busbar electrode 18B and second electrode fingers 20B extending from the second busbar electrode 18B toward the first busbar electrode 18A.

[0023] The reflector electrodes 16 (also referred to as reflector grids) each include a first reflector busbar electrode 24A and a second reflector busbar electrode 24B (collectively referred to herein as reflector busbar electrode 24) and reflector fingers 26 extending between and electrically coupling the first reflector busbar electrode 24A and the second reflector busbar electrode 24B.

[0024] In further embodiments disclosed herein, as in Fig. 1B, the reflector busbar electrodes 24A, 24B may be omitted and the reflector fingers 26 may not be electrically connected. Furthermore, as shown in Fig. 1C, acoustic wave resonators as disclosed herein include dummy electrode fingers 20C aligned with respective electrode fingers 20A, 20B. Each dummy electrode finger 20C extends from the opposite busbar electrode 18A, 18B as the respective electrode finger 20A, 20B with which it is aligned.

[0025] It should be noted that the Fig. 1A-1C, as well as the other circuit elements shown in other figures presented herein, are shown in highly simplified form. The relative dimensions of the various features are not drawn to scale. Furthermore, typical acoustic wave resonators would usually include a much larger number of electrode fingers and reflector fingers than shown. Typical acoustic wave resonators or filter elements may also include multiple IDT electrodes sandwiched between the reflector electrodes.

[0026] The operating parameters of SAW devices often vary with temperature. For example, in a high-frequency filter consisting of SAW resonators, the resonant and anti-resonant frequencies of the filter may decrease with temperature. The temperature dependence of SAW device parameters is undesirable, as a device that operates consistently under various operating conditions is typically desired. Accordingly, it may be desirable to dissipate the heat generated in an operating SAW device as quickly and efficiently as possible—i.e., to dissipate it to prevent the device from heating to a temperature at which the device's operating parameters shift by more than an acceptable amount.

[0027] A method for packaging a SAW device is described in Fig. 2. A cavity 26 is defined over the portion of the substrate 12 on which the IDT electrodes 14 (and reflector electrodes, not separately shown) are disposed by a cap layer and sidewalls of a dielectric material 28, for example, polyimide. Conductive vias 30 are formed through the cap layer of dielectric material and are electrically connected to contact pads 32 on the substrate 12, which are in electrical communication with the IDT electrodes 14. The conductive vias 30 provide an electrical connection between the contact pads 32 and external connection pads (also referred to as bonding pads or external connection or bonding pads) 34, which can be used to electrically connect the packaged SAW device to, for example, a printed circuit board.The conductive vias and external connection pads may be formed from a highly electrically and thermally conductive material, such as copper. The substrate 12, on which the IDT electrodes 14 are arranged, is arranged face down, so that the side of the substrate 12 containing the IDT electrodes 14 faces the external connection pads 34.

[0028] When mounted on a printed circuit board or other external substrate, a heat dissipation path for a packaged SAW device passes through the external connection pads, e.g., the Fig. 2, and into the circuit board or other external substrate. In order to be transferred out of the packaged device, the heat generated in parts of the device that are not in direct contact with the connection pads 34 would have to be transported through other parts of the device. Piezoelectric materials, such as LiTaO3, from which the substrate 12 can be formed, typically have low thermal conductivity compared to other materials, such as metals. A packaged SAW device, as shown in Fig. 2, heat may transfer from the device and through the bonding pads 34 and the substrate 12 less rapidly than would be desirable.

[0029] A method for increasing the rate and efficiency of heat transfer from a packaged SAW device as described in Fig. 2, consists in increasing the thermal conductivity of the substrate 12. The thermal conductivity of the substrate can be increased by removing part of the piezoelectric material of the substrate 12 and replacing it with a layer of dielectric material 12' with a higher thermal conductivity, e.g. spinel (MgAl2O4) as in Fig. 3 or silicon (Si) as shown in Fig. 4. Other materials, such as sapphire, aluminum nitride, silicon dioxide, or diamond, may be used additionally or alternatively for the layer of material 12'. The material layer 12' may be bonded or glued to the piezoelectric material of the substrate 12, for example, with a layer of silicon dioxide (SiO2) or another suitable bonding material. The bonding layer is shown as layer 22 in Fig. 8. The thickness of the piezoelectric material layer should be maintained at a thickness sufficient for the SAW device to operate properly, e.g., between about 0.3 µm and about 50 µm, or more than twice the wavelength λ of a main acoustic wave excited by the IDT electrodes of the SAW device. The material layer 12' may be between about 50 µm and about 300 µm thick. A layer connecting the piezoelectric material of the substrate 12 to the layer of material 12' may, for example, be between about 0.1 µm and about 50 µm thick.

[0030] A comparison of the thermal conductivity of various materials that can be used in embodiments of a packaged SAW device is given below in Table 1: Table 1: Comparison of thermal conductivity of selected materials Material Wärmeleitfähigkeit (W / mK) Lithium-Tantalat 2,93 Polyimid 3,1 Spinell (MgAl2O4) 16,2 Silizium 140 Kupfer 402

[0031] An alternative arrangement for a packaged SAW device is shown in Fig. 5. The packaged SAW device of Fig. 5 differs from that of Fig. 2 in that the surface of the substrate 12 on which the IDT electrodes 14 are formed faces away from the external connection pads 34 and the conductive vias 30 pass through the substrate 12 and not through the dielectric material 28, which forms a cap covering a cavity in which the IDT electrodes 14 are arranged. The embodiment of Fig. 5 has similar problems regarding heat dissipation as Fig. 3. Heat generated in parts of the packaged device that are not in direct contact with the conductive vias 30 would, for example, have to pass primarily through the low thermal conductivity substrate 12 to the conductive vias in order to be led out of the package. The conductive vias 30 of the embodiment of Fig. 5 may have a larger surface area in contact with the material of the substrate 12 and may thus enable more efficient heat transfer out of the substrate 12 and into a circuit board or other external substrate than the packaged SAW device of Fig. 2. However, this increase in heat transfer efficiency may be only slight and less than desirable.

[0032] In a similar way to the embodiments of the Fig. 3 and Fig. 4, a portion of the piezoelectric substrate 12 may be removed and replaced by a layer of dielectric material 12" having a higher thermal conductivity than the piezoelectric material. The material layer 12" may be spinel ( Fig. 6) or silicon ( Fig. 7) that is connected or bonded to the piezoelectric material, for example a layer of SiO2. Other materials, such as sapphire, aluminum nitride, silicon dioxide, or diamond, may additionally or alternatively be used for the layer of material 12". The conductive vias 30 pass through both the piezoelectric material portion 12 of the substrate and the layer of material 12". The external connection pads 34 may be arranged on the opposite side (the underside) of the material layer 12" as the piezoelectric material layer 12. The thickness of the piezoelectric material layer in the embodiments of the Fig. 6 and Fig. 7 and the thickness of the connecting layer may be the same or similar to the embodiments of Fig. 3 and Fig. 4. The thickness of the material layer 12" in the Fig. 6 and Fig. 7 may be smaller than the thickness of the material layer 12' in the Fig. 3 and Fig. 4. The thickness of the material layer 12" in the Fig. 6 and Fig. 7 can, for example, be between about 50 µm and about 300 µm.

[0033] The substrates 12 of the acoustic wave devices disclosed herein may include a single layer of a single piezoelectric material, for example, LiTaO3 or LiNbO3, as shown in the Fig. 2-8. However, it should be noted that in the claimed embodiments, the substrates 12 of one of the acoustic wave devices disclosed herein are multilayer piezoelectric substrates (MPS). As shown in Fig. As shown in Figure 9, an MPS includes a body with at least one, or two or more, for example, three or more piezoelectric thin-film material layers 12A, 12B, 12C. The different layers 12A, 12B, 12C can have at least two different electromechanical coupling coefficients. The central layer 12B has the largest electromechanical coupling coefficient of the layers 12A, 12B, 12B, 12C. This arrangement can concentrate energy of a surface acoustic wave on one surface of the MPS, so that the electromechanical coupling coefficient of the MPS as a whole is greater than that of each individual piezoelectric material layer. Suitable materials for the different piezoelectric material layers 12A, 12B, 12C can be, for example, ZnO, LiNbO3, LiTaO3, Pb[Zr x Ti 1-x]O3 (PZT), PbTiO3, BaTiO3, or Li2B4O7. In some implementations, only one of the layers 12A, 12B, 12C or two of the layers 12A, 12B, 12C may include or consist of piezoelectric material, and the remaining layers 12A, 12B, 12C may include or consist of a non-piezoelectric material, for example, a dielectric material.

[0034] The acoustic wave devices described here can be implemented in a variety of packaged modules. Below, some exemplary packaged modules are discussed in which all suitable principles and advantages of the packaged acoustic wave devices presented here can be implemented. Fig. 10, Fig. 11 and Fig. 12 are schematic block diagrams of illustrative packaged modules and devices according to certain embodiments.

[0035] As explained above, embodiments of the surface acoustic wave elements can be configured or used, for example, as filters. Conversely, a surface acoustic wave (SAW) filter with one or more surface acoustic wave elements can be integrated into a module and packaged as a module, which can ultimately be used in an electronic device, such as a wireless communication device. Fig. 10 is a block diagram illustrating an example of a module 300 including a SAW filter 310. The SAW filter 310 may be implemented on one or more dies 320 with one or more connection pads 322. For example, the SAW filter 310 may include a connection pad 322 corresponding to an input contact for the SAW filter and another pad 322 corresponding to an output contact for the SAW filter. The packaged module 300 includes a packaging substrate 330 configured to receive a plurality of components, including the die 320.A plurality of connection pads 332 may be disposed on the packaging substrate 330, and the various connection pads 322 of the SAW filter die 320 may be connected to the connection pads 332 on the packaging substrate 330 via electrical connectors 334, which may be, for example, solder bumps or wire bonds, to enable the routing of various signals to and from the SAW filter 310. The module 300 may optionally also include other circuit die 340, such as one or more additional filters, amplifiers, pre-filters, modulators, demodulators, buck converters, and the like, as would be known to one of ordinary skill in the semiconductor manufacturing art in view of the disclosure provided herein. In some embodiments, the module 300 may also include one or more packaging structures, for example, to provide protection and facilitate handling of the module 300.Such a packaging structure may include an overmold formed around the packaging substrate 330 and sized to substantially encapsulate the various circuits and components thereon.

[0036] Various examples and embodiments of the SAW filter 310 can be used in a variety of electronic devices. For example, the SAW filter 310 can be used in an antenna duplexer, which in turn can be integrated into a variety of electronic devices such as RF front-end modules and communication devices.

[0037] With reference to Fig. Figure 11 shows a block diagram of 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 with a common node 402, an input node 404, and an output node 406. An antenna 510 is connected to the common node 402.

[0038] 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 passband(s) of the transmit filter(s) differ from the passband(s) of the receive filters. Examples of the SAW filter 310 may be used to form the transmit filter(s) 412 and / or the receive filter(s) 414. An inductor or other matching component 420 may be connected to the common node 402.

[0039] 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 signals for transmission via the antenna 510, and the receiver circuit 434 may receive and process signals received via the antenna 510. In some embodiments, the receiver and transmitter circuits are implemented as separate components, as shown in Fig. 11, however, in other embodiments, these components may be integrated into a common transceiver circuit or module. As those of ordinary skill in the art will recognize, the front-end module 400 may include other components not shown in Fig. 11, including but not limited to switches, electromagnetic couplers, amplifiers, processors, and the like.

[0040] Fig. 12 is a block diagram of an example of a wireless device 500 having the Fig. 11. The wireless device 500 may be a mobile phone, smartphone, tablet, modem, communication network, or other portable or non-portable device configured for voice or data communication. The wireless device 500 may receive and transmit signals from the antenna 510. The wireless device includes an embodiment of a front-end module 400, similar to that discussed above with reference to Fig. 11. The front-end module 400 includes the duplexer 410, as explained above. In the Fig. 12, the front-end module 400 further includes an antenna switch 440 that can be configured to switch between different frequency bands or modes, such as transmit and receive modes. In the example shown in Fig. In the example illustrated in Figure 12, the antenna switch 440 is positioned between the duplexer 410 and the antenna 510; however, in other examples, the duplexer 410 may be positioned between the antenna switch 440 and the antenna 510. In further examples, the antenna switch 440 and the duplexer 410 may be integrated into a single component.

[0041] The front-end module 400 includes a transceiver 430 configured to generate signals for transmission or process received signals. The transceiver 430 may include the transmitter circuit 432, which may be connected to the input node 404 of the duplexer 410, and the receiver circuit 434, which may be connected to the output node 406 of the duplexer 410, as in the example of Fig. 10 shown, include.

[0042] Signals generated for transmission by transmitter circuitry 432 are received by a power amplifier (PA) module 450, which amplifies the signals generated by transceiver 430. Power amplifier module 450 may include one or more power amplifiers. Power amplifier module 450 may be used to amplify a variety of transmission signals related to RF or other frequency bands. For example, power amplifier module 450 may receive an enable signal that allows the output of the power amplifier to be pulsed to support the transmission of a wireless local area network (WLAN) signal or other suitable pulsed signal.The power amplifier module 450 can be configured to amplify any type of signal, including, for example, a Global System for Mobile (GSM) signal, a Code Division Multiple Access (CDMA) signal, a W-CDMA signal, a Long-Term Evolution (LTE) signal, or an EDGE signal. In certain embodiments, the power amplifier module 450 and associated components, including switches and the like, can be fabricated on gallium arsenide (GaAs) substrates, e.g., using high-electron mobility transistors (pHEMT) or insulated-gate bipolar transistors (BiFET), or on a silicon substrate using complementary metal-oxide semiconductor (CMOS) field-effect transistors.

[0043] The front-end module 400 may further include a low-noise amplifier module 460 that amplifies received signals from the antenna 510 and provides the amplified signals to the receiver circuit 434 of the transceiver 430.

[0044] The wireless device 500 of Fig. 12 further includes a power management system (also referred to as a power management system) 520 connected to the transceiver 430 and managing power for operation of the wireless device 500. The power management system 520 may also control the operation of a 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 further include one or more processors or controllers that may, for example, control the transmission of signals.In one embodiment, baseband subsystem 530 is connected to a user interface 540 to enable various inputs and outputs of voice and / or data provided to and received from the user. Baseband subsystem 530 may also be connected to memory 550, which is configured to store data and / or instructions to facilitate operation of the wireless device and / or to allow the user to store information. Any of the embodiments described above may be implemented in connection with mobile devices, such as cellular phones. The principles and advantages of the embodiments may be used for any systems or devices, such as any uplink wireless communication device, that could benefit from any of the embodiments described herein. The teachings contained herein apply to a variety of systems.Although this disclosure includes some exemplary embodiments, the teachings described herein may be applied to a variety of structures. Each of the principles and advantages described herein may be implemented in connection with RF circuits configured to process signals in a range of about 30 kHz to 5 GHz, for example, in a range of about 600 MHz to 2.7 GHz.

[0045] Aspects of this disclosure may be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronic products, parts of consumer electronic products such as packaged radio frequency modules, wireless uplink communication devices, wireless communication infrastructure, electronic test equipment, etc.Examples of electronic devices may include, but are not limited to, a mobile phone such as a smartphone, a portable computing device such as a smart watch or earpiece, a telephone, a television, a computer monitor, a computer, a modem, a wearable computer, a laptop, a tablet computer, a microwave, a refrigerator, a vehicle electronics system such as an automotive electronics system, a stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a washing machine, a dryer, a washer and dryer, a copier, a fax machine, a scanner, a multifunctional peripheral device, a wristwatch, a clock, etc. In addition, the electronic devices may also include unfinished products. Example:

[0046] Simulations were performed to determine the thermal contact resistance R from the IDT electrodes 14 to the external bonding pads 34 in each of the Fig. 2-7. The simulations for the embodiments of the Fig. 2-4 were carried out with a simulated device that simulated the Fig. 13A-13C. The simulations for the embodiments of the Fig. 5-7 were carried out with a simulated device that simulated the Fig. 14A-14C. The simulation results were as follows: Table 2: Results of thermal resistance simulations Ausführungsform ThermischerÜbergangswiderstand(Grad / W) Fig. 2 (Flip-Chip-Lithium-Tantalatsubstrat) 108 Fig. 3 (Flip-chip lithium tantalate and spinel-coated substrate) 34 Fig. 4 (Flip-chip lithium tantalate and silicon-coated substrate) 12,6 Fig. 5 (Lithium-tantalate substrate) 84 Fig. 6 (Lithium tantalate and spinel-coated substrate) 22,3 Fig. 7 (Lithium tantalate and silicon-coated substrate) 6,3

[0047] These results indicate that packaged SAW devices, as described in the Fig. 5-7, have a more desirable (lower) thermal contact resistance than the corresponding packaged SAW devices of the Fig. 2-4. The thermal contact resistance decreased with increasing thermal conductivity of the material or materials forming the substrates of the packaged devices.

[0048] It should be noted that the dimensions and characteristics of the simulated devices or equipment of the Fig. 13A-13C and 14A-14C apply to a device with an operating frequency between 600 MHz and 3.7 GHz. For devices operating at other frequencies, the dimensions and features, such as the number of contacts, the thickness of the silicon or spinel or piezoelectric material layers, the number or arrangement of electrode fingers, etc., may vary from those shown here.

[0049] Unless the context clearly indicates otherwise, the phrases "comprises," "includes," "includes," "including," and the like are to be interpreted in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is, in the sense of "including, but not limited to." The word "coupled," as used generally herein, refers to two or more elements that may be either directly connected to one another or connected via one or more intermediate elements. Likewise, the word "connected," as used generally herein, refers to two or more elements that may be either directly connected or connected via one or more intermediate elements. Furthermore, the words "here," "above," "below," and words of similar import, when used in this disclosure, refer to this disclosure as a whole and not to any particular portion of this disclosure.Where the context permits, words in the above detailed description containing the singular or plural number may also include the plural or singular. The word "or" in reference to a list of two or more items covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0050] In addition, the conditional language used herein, such as, but not limited to, “may,” “could,” “might,” “could possibly,” “e.g.,” “for example,” “such as,” and the like, unless expressly stated otherwise or otherwise understood within the context used, is generally intended to convey that certain embodiments include certain features, elements, and / or conditions, while other embodiments do not include certain features, elements, and / or conditions.Therefore, such conditional language is generally not intended to imply that features, elements, and / or conditions are in any way required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether to include or implement those features, elements, and / or conditions in a particular embodiment, with or without input or prompting from the author.

[0051] Although specific embodiments have been described, these embodiments have been presented only by way of example and are not intended to limit the scope of the disclosure. Indeed, the novel devices, methods, and systems described herein may be embodied in a variety of other forms; further, various omissions, substitutions, and changes in the design of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are shown in a particular arrangement, alternative embodiments may perform similar functionality with different components and / or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and / or altered. Each of these blocks may be implemented in a variety of ways.Any suitable combination of the elements and acts of the various embodiments described above may be combined to form further embodiments. The appended claims and their equivalents are intended to cover such embodiments or modifications that would fall within the scope and spirit of the disclosure.

Claims

[1] High frequency filter, comprising: at least one acoustic wave device (10) comprising: a layered substrate having a piezoelectric material layer (12) comprising a multilayer piezoelectric substrate having three layers (12A, 12B, 12C) bonded to a second material layer (12'; 12") comprising a material having a higher thermal conductivity than the piezoelectric material layer (12), of which a central layer (12B) of the three layers (12A, 12B, 12C) has the largest electromechanical coupling coefficient; interdigital transducer electrodes (14) arranged on a surface of the piezoelectric material layer (12); Contact pads (32) arranged on the piezoelectric material layer (12) and in electrical contact with the interdigital transducer electrodes (14); external connection pads (34) arranged on the second material layer (12'; 12"); and conductive vias (30) passing through the layered substrate (12; 12'; 12'; 12") and establishing electrical contact between the contact pads (32) and external connection pads (34). [2] Electronic module, comprising: at least one high-frequency filter with at least one acoustic wave device (10) comprising: a layered substrate having a piezoelectric material layer (12) comprising a multilayer piezoelectric substrate having three layers (12A, 12B, 12C) bonded to a second material layer (12'; 12") comprising a material having a higher thermal conductivity than the piezoelectric material layer (12), wherein the piezoelectric material layer (12) comprises a multilayer piezoelectric substrate having three layers (12A, 12B, 12C), of which a central layer (12B) of the three layers (12A, 12B, 12C) has the largest electromechanical coupling coefficient; interdigital transducer electrodes (14) arranged on a surface of the piezoelectric material layer (12); Contact pads (32) arranged on the piezoelectric material layer (12) and in electrical contact with the interdigital transducer electrodes (14); external connection pads (34) arranged on the second material layer (12'; 12"); and conductive vias (30) passing through the layered substrate (12; 12'; 12'; 12") and establishing electrical contact between the contact pads (32) and external connection pads (34). [3] Acoustic wave device (10) comprising: a layered substrate having a piezoelectric material layer (12) comprising a multilayer piezoelectric substrate having three layers (12A, 12B, 12C) bonded to a second material layer (12'; 12") comprising a material having a higher thermal conductivity than the piezoelectric material layer (12), of which a central layer (12B) of the three layers (12A, 12B, 12C) has the largest electromechanical coupling coefficient; interdigital transducer electrodes (14) arranged on a surface of the piezoelectric material layer (12); Contact pads (32) arranged on the piezoelectric material layer (12) and in electrical contact with the interdigital transducer electrodes (14); a cavity defined above the interdigital transducer electrodes (14) by walls and a cap (28) comprising a dielectric material; external connection pads (34) arranged on the cap (28) on an opposite side of the cap (28) from the cavity; and conductive vias (30) extending through the cap (28) and establishing electrical contact between the contact pads (32) and external connection pads (34). [4] Acoustic wave device (10) comprising: a layered substrate having a piezoelectric material layer (12) comprising a multilayer piezoelectric substrate having three layers (12A, 12B, 12C) bonded to a second material layer (12'; 12") comprising a material having a higher thermal conductivity than the piezoelectric material layer (12), of which a central layer (12B) of the three layers (12A, 12B, 12C) has the largest electromechanical coupling coefficient; interdigital transducer electrodes (14) arranged on a surface of the piezoelectric material layer (12); Contact pads (32) arranged on the piezoelectric material layer (12) and in electrical contact with the interdigital transducer electrodes (14); external connection pads (34) arranged on the second material layer (12'; 12"); and conductive vias (30) passing through the layered substrate (12; 12'; 12'; 12") and establishing electrical contact between the contact pads (32) and external connection pads (34), each of which extends in a straight line through the layered substrate (12; 12'; 12'; 12") between the contact pads (32) and the external connection pads (34). [5] The acoustic wave device (10) of claim 4, wherein the second material layer (12'; 12") includes a dielectric material. [6] The acoustic wave device (10) of claim 5, wherein the second material layer (12'; 12") comprises spinel. [7] The acoustic wave device (10) of claim 5, wherein the second material layer (12'; 12") comprises silicon. [8] Acoustic wave device (10) according to one of claims 4 to 7, further comprising a connecting layer (22) connecting the piezoelectric material layer (12) to the second material layer (12'; 12"). [9] The acoustic wave device (10) of claim 8, wherein the bonding layer (22) comprises silicon dioxide. [10] Acoustic wave device (10) according to one of claims 4 to 9, wherein the second material layer (12'; 12") has a thickness between 50 µm and 150 µm. [11] Acoustic wave device (10) according to one of claims 4 to 10, wherein the piezoelectric material layer (12) has a thickness between 0.3 µm and 20 µm. [12] An acoustic wave device (10) according to any one of claims 4 to 11, configured as a surface acoustic wave resonator.

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