An elastic wave device, a manufacturing method thereof, and an electronic device

Abstract

This application discloses an elastic wave device, its manufacturing method, and an electronic device thereof. The elastic wave device includes a support substrate made of a conductive metal material, a piezoelectric layer disposed on its surface, and an electrode layer disposed away from the support substrate. The device also integrates a conductive connection structure penetrating the piezoelectric layer, through which the support substrate forms an electrical conduction path with at least one ground terminal of the electrode layer. This application achieves electrical interconnection between the metal support substrate and the electrode layer through the conductive connection structure, particularly clamping the substrate to a reference ground potential. This effectively solves the problem of parasitic capacitive coupling between the metal substrate and the electrode layer in a suspended state, significantly improving the out-of-band rejection and isolation performance of the device while retaining the advantages of high heat dissipation and high power tolerance of the metal substrate.

Description

Technical Field

[0001] This application relates to the field of communication devices, and mainly to an elastic wave device, its manufacturing method, and electronic devices. Background Technology

[0002] With the rapid development of mobile communication technologies (such as 4G, 5G and 6G), the performance requirements of radio frequency front-end modules for filters are becoming increasingly stringent, especially in terms of high frequency, miniaturization and high power tolerance.

[0003] Traditional surface acoustic wave (SAW) devices are typically based on piezoelectric single-crystal substrates such as lithium niobate or lithium tantalate. To further improve the quality factor (Q value) and temperature stability, the industry has developed composite substrate technologies based on "piezoelectric thin film / dielectric layer / supporting substrate" (such as POI and IHP SAW). In composite substrates, using metal materials with high thermal conductivity (such as molybdenum and tungsten) as the supporting substrate has become a highly promising technical approach to solve heat dissipation problems and improve power capacity.

[0004] However, existing technologies face a significant technical obstacle when using metallic materials as support substrates: as conductors, when the metallic substrate is electrically levitated, it forms non-negligible parasitic capacitances with the interdigitated electrodes (IDTs), pads, and traces on the device surface. These parasitic capacitances introduce additional signal coupling paths, severely degrading the out-of-band rejection performance of filters. Especially in duplexer applications, this can lead to a significant decrease in isolation between the transmit channel (Tx) and the receive channel (Rx), and may even cause the device to fail to meet communication standards and thus malfunction.

[0005] Therefore, how to eliminate the parasitic capacitance side effects while utilizing the high heat dissipation advantage of metal substrates is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the problems existing in the prior art, this application proposes an elastic wave device, its manufacturing method, and electronic components.

[0007] According to a first aspect of the present invention, an elastic wave device is provided, comprising: Support substrate, which is made of conductive metal material; A piezoelectric layer is disposed on the surface of the supporting substrate; An electrode layer is disposed on the side of the piezoelectric layer away from the supporting substrate, and a ground terminal is disposed on the electrode layer; The system also includes a conductive connection structure that penetrates the piezoelectric layer and connects to a supporting substrate. The supporting substrate forms an electrical conductive path with at least one ground terminal of the electrode layer through the conductive connection structure. This application constructs a novel physical architecture of "metal substrate + piezoelectric layer + conductive connection structure". Through the physically penetrating conductive connection structure, the metal substrate is forcibly clamped to the reference ground potential (zero potential), transforming it from a plate of parasitic capacitance into an electrostatic shielding layer. This eliminates floating charges on the substrate, cuts off the capacitive coupling path through the substrate, significantly suppresses stray signals, and solves the parasitic capacitance problem.

[0008] Preferably, the material of the support substrate includes one of molybdenum, tungsten, platinum, tantalum, gold, copper, or an alloy thereof. These materials not only possess excellent thermal conductivity (enhancing heat dissipation and power tolerance), but also have high acoustic impedance and a coefficient of thermal expansion that easily matches the piezoelectric layer, contributing to improved mechanical stability and acoustic quality factor (Q value) of the device.

[0009] More preferably, the number of conductive connection structures is one or more. Using one or more conductive connection structures can effectively eliminate parasitic capacitive coupling caused by the metal support substrate being in an electrically levitated state, cutting off stray signal paths and thus significantly improving the out-of-band suppression capability of the elastic wave device. Simultaneously, as the number of conductive connection structures increases (e.g., by using multiple apertures), a lower inductance parallel grounding loop can be constructed between the metal support substrate and the electrode layer, further suppressing signal crosstalk in specific frequency bands, resulting in a progressively significant improvement in the device's isolation performance.

[0010] Further preferably, the number of conductive connection structures is three. Using three conductive connection structures is the best implementation method to achieve optimal overall performance in this application. Through three etched holes for multi-point grounding, the electrical performance degradation caused by the suspension of the metal support substrate can be fully repaired, enabling its overall RF performance (such as out-of-band insertion loss, suppression, and isolation) to reach an excellent level comparable to that of traditional insulating substrates. More importantly, while maintaining this high level of electrical performance, the thermal conduction bottleneck of traditional insulating materials is completely broken, successfully finding the optimal balance between electrical shielding and thermal conduction, significantly improving the device's heat dissipation capacity and high-frequency, high-power tolerance.

[0011] Preferably, the device further includes a temperature compensation layer located between the supporting substrate and the piezoelectric layer; the conductive connection structure penetrates through the piezoelectric layer and the temperature compensation layer. Introducing the temperature compensation layer improves the frequency temperature coefficient of the device; simultaneously, by defining the conductive structure to penetrate through the piezoelectric layer and the temperature compensation layer, it ensures that even with the obstruction of the insulating temperature compensation layer, the metal substrate can be effectively brought out, solving the electrical interconnection problem in multilayer dielectric structures.

[0012] In a further preferred embodiment, the conductive connection structure includes a metal dielectric, the bottom surface of which is in direct contact with the supporting substrate, and the top surface of which is electrically connected to the grounding terminal.

[0013] Further preferably, the elastic wave device is a duplexer, and the electrode layer includes a transmit channel circuit area, a receive channel circuit area, and a common port area; the ground terminal is a common ground pad located in the common port area, which is situated between the transmit channel circuit area and the receive channel circuit area in the layout. In the duplexer, the common terminal is where the Tx and Rx signals intersect. Substrate shielding and grounding this point can most effectively prevent the transmitted signal from leaking to the receiver, greatly improving the cross-isolation of the duplexer.

[0014] According to a second aspect of the present invention, a method for manufacturing an elastic wave device is provided, comprising: S1: Provides a support substrate, which is made of conductive metal material and serves as the carrier for the elastic wave device; S2: Form a piezoelectric layer on the surface of the support substrate; S3: Etch at a predetermined position in the piezoelectric layer to form at least one through hole that penetrates the piezoelectric layer and exposes the surface of the supporting substrate, and form a conductive connection structure in the through hole; S4: An electrode layer is formed on the surface of the piezoelectric layer away from the support substrate; wherein the step of forming the electrode layer includes forming at least one ground terminal and physically connecting the ground terminal to a conductive connection structure, thereby establishing an electrical conduction path between the support substrate and the ground terminal through the conductive connection structure.

[0015] Preferably, S2 specifically includes: forming a temperature compensation layer on the surface of the support substrate; forming a piezoelectric layer on the surface of the temperature compensation layer; wherein, the etching process in S3 is configured to: continuously etch through the piezoelectric layer and the temperature compensation layer until the metal surface of the support substrate is exposed.

[0016] Preferably, the number of conductive connection structures in S3 is 3.

[0017] According to a third aspect of the present invention, an electronic device is provided, comprising the elastic wave device as described above.

[0018] This application proposes an elastic wave device, its manufacturing method, and an electronic device, which have the following significant advantages: This invention solves the technical bottleneck of parasitic capacitance in metal substrates. By using an innovative conductive connection structure to achieve equipotential connection between the metal substrate and the electrode layer (especially the grounding end), the parasitic capacitance effect caused by the suspension of the metal substrate is fundamentally eliminated, enabling the metal substrate to be truly used in high-performance RF filters.

[0019] While retaining the excellent thermal conductivity of the metal substrate (thus improving the device's power tolerance), a specific grounding topology design (connected to the ground terminal) significantly enhances the device's out-of-band rejection and isolation. Experiments show that this design can significantly improve the Tx-Rx isolation performance of the duplexer.

[0020] This application actually utilizes a metal support substrate to construct a built-in "Faraday cage" or "grounding plane", which not only eliminates its own negative impact, but also provides a better electromagnetic shielding environment for surface acoustic waves and improves the signal-to-noise ratio.

[0021] The structure proposed in this application is compatible with existing MEMS wafer-level packaging processes, and further improves the electrical stability and reliability of the device at high frequencies through a multi-point low-inductance interconnect design. Attached Figure Description

[0022] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of this application. Other embodiments and many anticipated advantages of these embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0023] Figures 1a-1b A schematic diagram of the structure of an elastic wave device in the prior art is shown; Figure 2 A schematic diagram of the structure of an elastic wave device according to an embodiment of this application is shown; Figure 3 A schematic diagram of the connection electrode layer to the duplex filter substrate is shown in a specific embodiment of this application; Figure 4 A schematic diagram of the electrode layer connected to the simplex filter substrate according to a specific embodiment of this application is shown; Figures 5a-5i A comparative graph of experimental performance curves for a specific embodiment of this application is shown; Figure 6 A flowchart illustrating a method for manufacturing an elastic wave device according to an embodiment of this application is shown.

[0024] Reference numerals: In prior art drawings, 110. Supporting substrate; 120. Temperature compensation layer; 130. Piezoelectric layer; 140. Electrode layer; In the drawings of embodiments of this application, 210. Supporting substrate; 220. Temperature compensation layer; 230. Piezoelectric layer; 240. Electrode layer; 250. Metal ball; 260. Conductive connection structure. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. It should also be noted that the drawings of this invention are not to scale.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Figures 1a-1b A schematic diagram of the structure of an elastic wave device in the prior art is shown. Figure 1a This is a simple elastic wave device consisting only of a piezoelectric layer 130 and an electrode layer 140. For example... Figure 1b As shown, the widely used elastic wave devices in the prior art have a stacked structure, which, from bottom to top, includes a support substrate 110, a temperature compensation layer 120, a piezoelectric layer 130, and an electrode layer 140. In this structure, the support substrate 110 serves as the mechanical support component of the device and is typically made of insulating dielectric materials such as silicon (Si), sapphire, or spinel. The temperature compensation layer 120 is disposed on the surface of the support substrate 110 and utilizes the material properties of a negative temperature coefficient to offset the influence of temperature changes on the device's performance. It is typically made of silicon dioxide (SiO2) to compensate for the frequency temperature coefficient of the piezoelectric layer 130. The piezoelectric layer 130 is bonded to the temperature compensation layer 120 and is typically a lithium niobate (LN) or lithium tantalate (LT) thin film. The electrode layer 140 is formed on the side of the piezoelectric layer 130 facing away from the support substrate 110 and typically includes an interdigital transducer (IDT) for exciting acoustic waves and a reflective grating. To improve the heat dissipation performance of the device, existing technologies propose replacing the support substrate 110 with a material of high thermal conductivity. In this structure, if the support substrate 110 is replaced with a metallic material (such as molybdenum or tungsten), the support substrate 110, made of metallic material, is electrically suspended and no effective electrical connection is established. Therefore, as a floating conductor, the support substrate 110 forms a parasitic capacitance with the top electrode layer 140 (especially the signal transmission electrode). This parasitic capacitance couples through the electrode layer 140 and the substrate 110, causing signal leakage or crosstalk, thereby deteriorating the out-of-band suppression and isolation performance of the elastic wave device.

[0028] To address the problems in the prior art, the present invention provides an improved elastic wave device. Figure 2 A schematic diagram of the structure of an elastic wave device according to an embodiment of this application is shown, as follows: Figure 2As shown, the elastic wave device provided in this embodiment adopts a multi-layer stacked structure, which includes, from bottom to top, a support substrate 210, a temperature compensation layer 220, a piezoelectric layer 230, and an electrode layer 240. In addition, the device also has a conductive connection structure 260 for interlayer interconnection and metal ball 250 for external packaging connection.

[0029] In a specific embodiment, the support substrate 210 is made of a conductive metal material with high thermal conductivity (e.g., one of molybdenum, tungsten, platinum, tantalum, gold, copper, or an alloy thereof). This support substrate 210 not only serves as the mechanical support for the entire device, but its excellent thermal conductivity also acts as a heat sink, effectively dissipating the Joule heat generated when the device operates at high power, thereby significantly improving the device's power tolerance. A temperature compensation layer 220 (e.g., a silicon dioxide layer) is disposed on the upper surface of the support substrate 210 to compensate for the frequency temperature coefficient of the piezoelectric layer 230, improving the device's temperature stability. The piezoelectric layer 230 (e.g., a lithium tantalate or lithium niobate film) is bonded to the temperature compensation layer 220 to achieve the mutual conversion of electrical energy and acoustic energy. An electrode layer 240 is disposed on the side of the piezoelectric layer 230 facing away from the support substrate 210, and includes interdigitated electrodes (IDTs) for exciting acoustic waves and electrode pads for signal transmission or grounding.

[0030] Furthermore, this application is not limited to the following: Figure 2 In some other embodiments of the stacked structure shown, different stacks such as a low-velocity layer, a high-velocity layer, and an insulating layer may be provided between the piezoelectric layer 230 and the support substrate 210, depending on specific needs.

[0031] In this embodiment, a through conductive connection structure 260 is provided at a predetermined position between the piezoelectric layer 230 and the temperature compensation layer 220. This conductive connection structure 260 continuously penetrates the piezoelectric layer 230 and the temperature compensation layer 220 until the metal surface of the bottom supporting substrate 210 is exposed. As mentioned above, this application can also provide different stacked layers, such as a low-velocity layer, a high-velocity layer, or an insulating layer, between the piezoelectric layer 230 and the supporting substrate 210, as long as the conductive connection structure 260 is continuously penetrating from the piezoelectric layer 230 to the metal surface of the supporting substrate 210.

[0032] The conductive connection structure 260 is a conductive metal medium filling the through-holes of the piezoelectric layer 230 and the temperature compensation layer 220. The bottom of this conductive metal medium is in direct physical contact with and electrically connected to the support substrate 210, while the top is connected to the ground terminal in the electrode layer 240. Through the vertical electrical path constructed by the conductive connection structure 260, the conductive support substrate 210 is forced to connect to the reference ground potential of the electrode layer 240, thus achieving an equipotential state. This connection method eliminates the parasitic capacitance effect generated when the support substrate 210 is suspended, constructing an electrostatic shielding layer for radio frequency signals, thereby significantly improving the out-of-band rejection performance of elastic wave devices; especially in duplexer applications, this structure effectively blocks signal crosstalk between the transmit and receive channels, greatly improving isolation.

[0033] Figure 3 A schematic diagram of the electrode layer connecting the substrate of a duplex filter according to a specific embodiment of this application is shown, as follows: Figure 3 As shown, this embodiment illustrates a complete electrode layout for an RF duplexer. This layout, located on the top electrode layer 240 of the device, mainly includes a transmitter port (TX), a receiver port (RX), a common antenna port (ANT), and multiple grounding pads (labeled GND1, GND2, GND3, and GND4) distributed at different locations in the circuit. Several conductive connection structures 260 are disposed near multiple metal balls 250, and these conductive connection structures 260 are connected to each grounding terminal.

[0034] In a specific embodiment, the circuit topology of the duplexer includes a transmit channel filter on the left (connected between the TX port and the ANT port) and a receive channel filter on the right (connected between the RX port and the ANT port). Ground pads GND2 and GND3 are arranged at and around the intersection of the transmit and receive channels. Ground pad GND2 is physically located at the boundary between the transmit channel circuit area and the common antenna port (ANT) area, playing a crucial interstage isolation role (corresponding to the aforementioned grounding terminal). In this embodiment, a conductive connection structure 260 is configured below or within the area of ​​ground pads GND2, GND3, and GND4. The conductive connection structure 260 electrically connects the bottom metal support substrate 210 (not shown in the figure, located at the bottom) to the ground pads GND2 and GND3 located in the core circuit area; this connection method allows the metal support substrate to construct a vertical electromagnetic shielding wall between the TX and ANT paths, cutting off parasitic coupling paths of the signals, thereby significantly improving the cross-isolation of the duplexer.

[0035] In a specific embodiment, the conductive connection structure 260 is also connected to the edge grounding pad GND4. This multi-point distributed connection method (i.e., simultaneously connecting GND2, GND3, and GND4) forms a low-inductance parallel grounding loop between the metal support substrate 210 and the electrode layer 240, ensuring the stability of the device under high-power operation.

[0036] It should be recognized that, in addition to the aforementioned application of duplexers, the technical solution proposed in this application for clamping the metal support substrate to the reference ground potential through a conductive connection structure can also be applied to simplexers and multiplexers, and can achieve the same technical effect of the present invention. Figure 4 A schematic diagram of the electrode layer connecting the simplex filter substrate according to a specific embodiment of this application is shown, as follows: Figure 4 As shown, this layout mainly includes a signal input terminal, a signal output terminal, and a ground terminal (GND). A conductive connection structure 260 is positioned within the ground terminal (GND) area, electrically connecting the bottom metal support substrate to the ground terminal (GND) of the electrode layer. This effectively cuts off the capacitive coupling path of stray signals while retaining the high heat dissipation advantage of the metal substrate, ensuring the out-of-band suppression capability and signal purity of various elastic wave devices such as simplex circuits.

[0037] Figures 5a-5i The following is a comparison graph of experimental performance curves for a specific embodiment of this application. Figure 5a The graph shows a comparison of the electrical performance of a filter using a metal substrate and a conventional filter using an insulating substrate when the conductive connection structure of this application is not employed. Figure 5aAs shown, the figure contains two coordinate systems, left and right, illustrating the filter's electrical performance characteristics (left) and isolation characteristics (right). The solid line represents the performance curve of the filter using a traditional spinel substrate (as a reference group), while the dashed line represents the performance curve using a molybdenum (Mo) metal substrate (as an experimental group). The left figure shows the passband transmission characteristics and out-of-band rejection capability. The comparison shows that compared to the spinel substrate device shown by the solid line, the Mo metal substrate device shown by the dashed line exhibits a slight deterioration in insertion loss within the passband, but the magnitude is not significant. However, in the out-of-band rejection regions on both sides of the passband, the dashed line is significantly higher than the solid line, indicating a substantial decrease in the filter's out-of-band rejection capability, making it unable to effectively filter out clutter. The right figure shows the isolation performance between the transmitter (TX) and receiver (RX). The solid line indicates that the spinel substrate has a deep isolation notch and good performance. In contrast, the isolation curve of the Mo metal substrate device, shown by the dashed line, shows a significant overall "rise" (the value increases, for example, deteriorating from -60dB to around -30dB), indicating a significant increase in interference between the transmitted signal and the received signal. Combining the two figures, it is clear that replacing insulating substrates such as spinel with only a Mo metal substrate leads to a decrease in out-of-band rejection and overall isolation performance. The main technical reason is that the Mo metal substrate is in a suspended state (due to the lack of grounding, it forms a potential float), acting as a large floating conductor. This creates parasitic capacitance between the substrate and the top electrode layer and the metal patterns on the packaging substrate. This parasitic capacitance couples to the radio frequency signal, disrupting the electromagnetic environment of the filter and thus degrading device performance. This experimental result confirms the necessity of introducing a grounding structure into the metal substrate architecture.

[0038] Figures 5b to 5e This illustration shows a comparison of the electrical performance of a filter when the metal substrate is grounded via an etched hole, compared to a filter with a metal substrate in a suspended state without etched holes, according to an embodiment of this application. Figures 5b to 5e As shown, the solid line represents the performance baseline when the metal substrate is electrically levitated without etched holes, and the dashed line represents the performance curve after the metal substrate is connected to the electrode layer through etched holes. Figures 5b-5eThe performance curves for the etched vias and GND1, GND2, GND3, and GND4 are shown respectively. Comparing the transmission characteristics on the left and the isolation characteristics on the right of the graph, it can be seen that compared to the substrate suspension state (solid line), after introducing etched vias to establish conductive connections (dashed line), the curves are significantly suppressed in the stopband regions on both sides of the passband, and the isolation curve shows a significant overall drop. This indicates that the conductive connection structure with etched vias can effectively eliminate parasitic capacitive coupling caused by the suspension of the metal substrate, resulting in a significant improvement in the out-of-band rejection capability and a significant increase in isolation. The overall electrical performance is significantly better than the suspended metal substrate architecture without etched vias. Furthermore, regardless of which ground terminal the etched via is located at, the performance is significantly improved compared to the metal substrate solution without etched vias.

[0039] Figure 5f The diagram shows a comparison of the filter's electrical performance in this embodiment, using two etched holes versus a single etched hole to ground the metal substrate. Figure 5f As shown, compared to the electrical performance (solid line) of connecting the electrode layer with a single etched via (GND4), the device maintains its excellent filtering characteristics with minimal change in out-of-band suppression in the left figure after simultaneously connecting the metal substrate and the electrode layer (GND2 and GND4 in this embodiment) through two etched vias (dashed line). However, in the critical frequency band region marked by the dotted line in the right figure, the dashed line representing the two etched vias shows a significant dip, further improving the isolation by approximately -55dB. This indicates that increasing the number of conductive connection structures on top of a single-via grounding can further suppress signal crosstalk in a specific frequency band. In other words, the isolation performance of the two-via structure is superior to that of a single-via structure, verifying the positive effect of increasing the number of grounding vias on improving the local electrical performance of the device.

[0040] Figure 5g The diagram shows the electrical performance curves of the filter according to the preferred embodiment of this application, further verifying the progressive improvement effect of the number of conductive connection structures on the overall performance of the device. Figure 5g As shown by the dashed lines, when three etched holes are used to electrically connect the metal substrate to the ground terminals (such as GND2, GND3, and GND4) of the electrode layer simultaneously, the overall out-of-band rejection and isolation of the device are improved to the greatest extent. Based on the test results of the aforementioned embodiments, it can be seen that the grounding shielding effect of the conductive connection structure significantly increases with the number of openings; that is, the overall electrical performance of the three-opening structure is better than that of the two-opening structure, and the two-opening structure is better than that of the single-opening structure. In summary, by removing part of the piezoelectric layer and temperature compensation layer through etching and filling the holes with conductive metal to connect the metal substrate and the electrode layer to form an equipotential, the electrical performance of the filter can be greatly improved. The conductive connection structure using three etched holes is the best implementation method for achieving optimal overall performance in this application.

[0041] Figure 5h The diagram shows a comparison of the electrical performance of a metal substrate filter with conductive connection structures (etched holes) and a conventional spinel insulating substrate filter, as illustrated in the embodiments of this application. Figure 5h As shown, the solid line represents the baseline performance of the filter using traditional spinel as the substrate, while the dashed line represents the filter performance curve of the present application with a metal substrate grounded via etched vias (e.g., GND4). Comparing the transmission and isolation characteristics in the figure reveals that the core electrical performance indicators, such as out-of-band rejection and isolation, of the metal substrate solution with etched vias in this application are not significantly different from those of the traditional spinel substrate. Although the electrical performance is slightly inferior to traditional insulating substrate technology in some frequency bands, the metal substrate used in this application overcomes the heat dissipation bottleneck of traditional insulating materials. By introducing the etched via grounding structure, this application not only successfully overcomes the problem of severe electrical performance degradation caused by the suspension of the metal substrate, restoring its RF performance to a level comparable to traditional technologies, but also greatly improves the device's heat dissipation performance and high power tolerance. In summary, this architecture achieves a good balance between heat dissipation and RF performance, with significant overall technical advantages, outweighing the disadvantages.

[0042] Figure 5i The diagram shows a comparison of the electrical performance of a filter using three etched holes to ground the metal substrate in an embodiment of this application, and a traditional spinel insulating substrate filter. (See diagram for reference.) Figure 5i As shown, the solid line represents the baseline performance of the filter using a traditional spinel substrate, while the dashed line represents the filter performance curve of the Mo metal substrate grounded through three etched vias (corresponding to GND2, GND3, and GND4) in this application. By comparing the transmission and isolation characteristics on both sides, it can be objectively seen that although the dashed line still shows slight differences compared to the traditional insulating substrate (solid line) at specific deep isolation notch locations and in some high-frequency out-of-band suppression, its trends in passband insertion loss and out-of-band suppression and isolation across most frequency bands are highly consistent with those of the traditional spinel substrate. This means that by grounding the metal substrate at multiple points through three etched vias, the electrical performance degradation caused by the suspension of the metal substrate has been fully repaired, and its overall RF performance has reached an excellent level comparable to traditional technologies. More importantly, while maintaining this similar high level of electrical performance, the metal substrate architecture of this application fundamentally breaks through the thermal conduction bottleneck of traditional insulating materials such as spinel. In summary, the metal substrate solution with multiple etched holes for grounding successfully found the optimal balance between electrical shielding and thermal conduction, achieving RF performance almost equivalent to traditional technologies while significantly improving the device's heat dissipation and high power tolerance.

[0043] Figure 6 A flowchart illustrating a method for manufacturing an elastic wave device according to an embodiment of this application is shown, as follows. Figure 6As shown, the manufacturing method includes the following steps: S1: Provide a support substrate, which is made of a conductive metal material and serves as the carrier of the elastic wave device. The conductive metal material of the support substrate is a metal with high thermal conductivity and high acoustic impedance, preferably one of molybdenum, tungsten, platinum, tantalum, gold, copper, or an alloy thereof.

[0044] S2: Forming a piezoelectric layer on the surface of the supporting substrate. This step may specifically include: Forming a temperature compensation layer: A dielectric material (such as silicon dioxide) is deposited on the surface of the metal support substrate to form a temperature compensation layer, which is used to improve the temperature characteristics of the device and isolate the metal substrate from the piezoelectric layer.

[0045] Forming a piezoelectric layer: Provide a piezoelectric single crystal wafer (such as lithium tantalate or lithium niobate) and bond it to the surface of the temperature compensation layer.

[0046] S3: Etching is performed at a predetermined location in the piezoelectric layer to form at least one through-hole penetrating the piezoelectric layer and exposing the surface of the supporting substrate, and a conductive connection structure is formed within the through-hole. Specific processes may include: Hole etching: Photolithography and etching are performed at predetermined locations on the piezoelectric layer (corresponding to the grounding pad locations in the subsequent design). The etching process is configured to continuously penetrate the piezoelectric layer and the thermal compensation layer until the etching stops at the metal surface of the supporting substrate, thereby forming a through-hole (blind via) that exposes the bottom metal supporting substrate.

[0047] Forming a conductive connection structure: A conductive connection structure is formed by filling the through-hole with metal material or depositing metal pillars through an electroplating process. The bottom of this conductive connection structure achieves direct physical contact and electrical conduction with the metal support substrate.

[0048] S4: An electrode layer is formed on the surface of the piezoelectric layer away from the support substrate; wherein the step of forming the electrode layer includes forming at least one ground terminal and physically connecting the ground terminal to a conductive connection structure, thereby establishing an electrical conduction path between the support substrate and the ground terminal through the conductive connection structure.

[0049] In a preferred embodiment, the number of conductive connection structures is three. By using three etched holes for multi-point grounding, the electrical performance degradation caused by the suspension of the metal support substrate can be fully repaired, enabling its overall RF performance (such as out-of-band insertion loss, suppression, and isolation) to reach an excellent level comparable to that of traditional insulating substrates. More importantly, while maintaining this high level of electrical performance, the thermal conductivity bottleneck of traditional insulating materials is completely overcome, successfully finding the optimal balance between electrical shielding and thermal conduction, significantly improving the device's heat dissipation capacity and high-frequency, high-power tolerance.

[0050] This application provides a high-power, high-performance elastic wave device and its manufacturing method, the core of which lies in solving the technical pain point of parasitic capacitance introduced by the metal support substrate due to electrical levitation. This solution innovatively introduces a conductive connection structure that penetrates the piezoelectric layer, forcibly clamping the metal substrate with high thermal conductivity to the reference ground potential, specifically connecting it to the inter-stage isolation grounding pad between the transmit and receive channels. This design not only retains the excellent heat dissipation and power tolerance of the metal substrate, but also effectively cuts off the signal coupling path by transforming it into a built-in three-dimensional electromagnetic shielding layer, significantly improving the out-of-band rejection capability of the filter, and raising the cross-isolation of the duplexer to an excellent level (e.g., -53dB), achieving a perfect balance between heat dissipation performance and RF performance in high-power scenarios.

[0051] The present invention also relates to an electronic device that may include the elastic wave device mentioned in any of the above embodiments.

[0052] The specific embodiments of this application have been described above, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0053] In the description of this application, it should be understood that the terms "upper," "lower," "inner," "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that combinations of these measures cannot be used for improvement. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An elastic wave device, characterized in that, include: A support substrate, wherein the support substrate is made of a conductive metal material; A piezoelectric layer is disposed on the surface of the supporting substrate; An electrode layer is disposed on the side of the piezoelectric layer away from the supporting substrate, and a ground terminal is provided on the electrode layer; It also includes a conductive connection structure that penetrates the piezoelectric layer and is connected to the support substrate. The support substrate forms an electrical conductive path with at least one ground terminal of the electrode layer through the conductive connection structure.

2. The elastic wave device according to claim 1, characterized in that, The material of the support substrate includes one of molybdenum, tungsten, platinum, tantalum, gold, copper, or an alloy thereof.

3. The elastic wave device according to claim 1, characterized in that, The number of conductive connection structures is one or more.

4. The elastic wave device according to claim 3, characterized in that, The number of conductive connection structures is three.

5. The elastic wave device according to claim 1, characterized in that, It also includes a temperature compensation layer, which is located between the supporting substrate and the piezoelectric layer; the conductive connection structure penetrates through the piezoelectric layer and the temperature compensation layer.

6. The elastic wave device according to claim 1, characterized in that, The conductive connection structure includes a metal dielectric, the bottom surface of which is in direct contact with the supporting substrate, and the top surface of which is electrically connected to the grounding terminal.

7. The elastic wave device according to claim 1, characterized in that, The elastic wave device is a duplexer, and the electrode layer includes a transmit channel circuit area, a receive channel circuit area, and a common port area; the ground terminal is a common ground pad located in the common port area, and the common ground pad is located between the transmit channel circuit area and the receive channel circuit area in the layout.

8. A method for manufacturing an elastic wave device, characterized in that, include: S1: Provide a support substrate, which is made of a conductive metal material and serves as the carrier of the elastic wave device; S2: A piezoelectric layer is formed on the surface of the supporting substrate; S3: Etching is performed at a predetermined position on the piezoelectric layer to form at least one through-hole penetrating the piezoelectric layer and exposing the surface of the supporting substrate, and a conductive connection structure is formed within the through-hole; and S4: An electrode layer is formed on the surface of the piezoelectric layer away from the supporting substrate; wherein the step of forming the electrode layer includes forming at least one ground terminal and physically connecting the ground terminal to the conductive connection structure, thereby establishing an electrical conduction path between the supporting substrate and the ground terminal through the conductive connection structure.

9. The manufacturing method according to claim 8, characterized in that, S2 specifically includes: forming a temperature compensation layer on the surface of the supporting substrate; forming a piezoelectric layer on the surface of the temperature compensation layer; wherein, the etching process in S3 is configured to: continuously etch through the piezoelectric layer and the temperature compensation layer until the metal surface of the supporting substrate is exposed.

10. The manufacturing method according to claim 8, characterized in that, The number of conductive connection structures in S3 is 3.

11. An electronic device, characterized in that, Includes the elastic wave device as described in any one of claims 1-7.

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