Surface acoustic wave filter device, forming method thereof and duplexer

Abstract

The surface acoustic wave filtering device provided by the embodiment of the invention comprises a substrate comprising a first part and a second part, the first part is located on the second part, and the heat conductivity coefficient of the second part is greater than that of the first part; a plurality of interdigital electrodes located on the substrate; wherein the first part comprises a piezoelectric material, and the second part comprises a mixing part which at least corresponds to a plurality of interdigital electrodes; wherein the mixing part comprises a plurality of first sub-parts and a plurality of second sub-parts which are arranged at intervals, the heat conductivity coefficient of the first sub-parts at the room temperature is smaller than 140 W / (m.K), and the heat conductivity coefficient of the second sub-parts at the room temperature is larger than 140 W / (m.K). By introducing the second part with a higher heat conductivity coefficient into the second part to form the mixed part, the overall heat conductivity coefficient of the second part is improved, so that heat is more efficiently led out from the first part, and the power tolerance and reliability of the device are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to surface acoustic wave (SAW) filtering devices, their formation methods, and duplexers. Background Technology

[0002] Radio frequency (RF) front-end chips in wireless communication devices include RF power amplifiers, RF switches, RF filters, RF multiplexers (e.g., duplexers, quadplexers, etc.), and low-noise amplifiers. Among these, RF filters include surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, and integrated passive device (IPD) filters.

[0003] SAW filters use interdigital transducers to excite the electromechanical coupling effect of piezoelectric materials. Heat is generated during the acoustic-electric energy conversion. If the heat cannot be effectively dissipated, the device temperature will rise, leading to device reliability issues. Summary of the Invention

[0004] This invention provides a surface acoustic wave filter device and its formation method, which can improve power tolerance and device reliability.

[0005] This invention provides a surface acoustic wave (SAW) filtering device, comprising: A substrate includes a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion being located on the second portion, the thermal conductivity of the second portion being greater than that of the first portion, the first portion including the first surface, and the second portion including the second surface; Multiple interdigitated electrodes are located on the first surface; The first part includes a piezoelectric material; The second part includes a mixing section corresponding to at least a plurality of interdigitated electrodes; wherein the mixing section includes a plurality of first sub-sections and a plurality of second sub-sections spaced apart; wherein the thermal conductivity of the first sub-section at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-section; wherein the thermal conductivity of the second sub-section at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-section.

[0006] Optionally, the thermal conductivity of the first sub-part at room temperature is less than 50 W / (m·K).

[0007] Optionally, the material of the first sub-part includes one of the following: lithium tantalate, lithium niobate, zinc oxide, glass, sapphire, quartz, spinel.

[0008] Optionally, the thermal conductivity of the second sub-part at room temperature is greater than 200 W / (m·K).

[0009] Optionally, the material of the second sub-part includes a metallic material; wherein the metallic material includes one of the following: aluminum, copper, nickel, gold, and titanium.

[0010] Optionally, the material of the second sub-part includes a non-metallic material; wherein the non-metallic material includes one of the following: diamond, cubic boron nitride, boron arsenide, aluminum nitride, gallium nitride, and beryllium oxide.

[0011] Optionally, the second part further includes a non-mixing portion, which is offset from the plurality of interdigitated electrodes; wherein the non-mixing portion has a thermal conductivity of less than 140 W / (m·K) at room temperature, and the second surface exposes the non-mixing portion.

[0012] Optionally, the thermal conductivity of the unmixed portion at room temperature is less than 50 W / (m·K).

[0013] Optionally, the material of the non-mixed portion includes one of the following: lithium tantalate, lithium niobate, zinc oxide, glass, sapphire, quartz, spinel.

[0014] Optionally, the plurality of the second sub-parts may be distributed in a dot matrix, a linear matrix, or a grid.

[0015] Optionally, the second sub-part has a rectangular or trapezoidal short cross-section along the direction perpendicular to the substrate.

[0016] Optionally, the second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid.

[0017] Optionally, the second portion includes the piezoelectric material; wherein the first sub-part includes the piezoelectric material, and the thermal conductivity of the intermediate layer is less than that of the first portion; wherein the piezoelectric material includes one of the following: lithium tantalate, lithium niobate, and zinc oxide; wherein the second sub-part penetrates the second portion and contacts the first portion.

[0018] Optionally, the thickness of the first portion ranges from 0.05λ to λ, where λ is the wavelength of the acoustic wave generated by the excitation.

[0019] Optionally, the first portion includes an intermediate layer and a piezoelectric layer located on the intermediate layer, the intermediate layer being located between the second portion and the piezoelectric layer; wherein the material of the piezoelectric layer includes one of the following: lithium tantalate, lithium niobate, and zinc oxide; wherein the thermal conductivity of the intermediate layer is greater than that of the piezoelectric layer, and the thermal conductivity of the intermediate layer is less than that of the second portion; wherein a plurality of second sub-parts penetrate the second portion and contact the intermediate layer.

[0020] Optionally, the material of the intermediate layer includes: aluminum nitride, silicon nitride, and aluminum oxide; the material of the first sub-part includes one of the following: glass, sapphire, quartz, and spinel.

[0021] Optionally, the second portion includes a substrate and an intermediate layer located on the substrate, the intermediate layer being located between the substrate and the first portion; wherein the material of the first portion includes one of the following: lithium tantalate, lithium niobate, and zinc oxide; wherein a plurality of second sub-parts penetrate the second portion and contact the first portion.

[0022] Optionally, the material of the intermediate layer includes: silicon dioxide, silicon oxynitride; the material of the substrate includes one of the following: glass, sapphire, quartz, spinel.

[0023] Optionally, the second part has a thermal conductivity greater than 140 W / (m·K) at room temperature.

[0024] A duplexer includes: the first filtering device described above, for transmitting electrical signals.

[0025] Optionally, it also includes: the second filtering device described above, used to receive electrical signals.

[0026] A method for forming a surface acoustic wave filter includes: A substrate is formed, including a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion is located on the second portion, the thermal conductivity of the second portion is greater than that of the first portion, the first portion includes the first surface, and the second portion includes the second surface; Multiple interdigitated electrodes are formed on the first surface; The first part includes a piezoelectric material; The second part includes a mixing section corresponding to at least a plurality of interdigitated electrodes; wherein the mixing section includes a plurality of first sub-sections and a plurality of second sub-sections spaced apart; wherein the thermal conductivity of the first sub-section at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-section; wherein the thermal conductivity of the second sub-section at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-section.

[0027] Optionally, the second part further includes a non-mixing portion, which is offset from the plurality of interdigitated electrodes; wherein the non-mixing portion has a thermal conductivity of less than 140 W / (m·K) at room temperature, and the second surface exposes the non-mixing portion.

[0028] Optionally, the plurality of the second sub-parts may be distributed in a dot matrix, a linear matrix, or a grid.

[0029] Optionally, forming the substrate further includes: forming a through-hole that penetrates the substrate; forming a connecting line located in the through-hole for electrically connecting the interdigitated electrodes; wherein the connecting line is formed synchronously with the second sub-part.

[0030] The beneficial effects of the present invention are as follows: The surface acoustic wave filter device provided in the embodiments of the present invention introduces a second part with a higher thermal conductivity to form the hybrid part in the second part, thereby improving the overall thermal conductivity of the second part, so as to more efficiently remove heat from the first part and improve the power tolerance and reliability of the device.

[0031] Furthermore, the material of the second sub-part includes non-metallic materials, thereby avoiding parasitic capacitance, parasitic inductance, and electrostatic discharge, and preventing the introduction of additional electrical losses.

[0032] Furthermore, the material of the second sub-part includes metallic material, and multiple second sub-parts are distributed in a high-order lattice, a high-order linear array, or a grid, thereby increasing the distribution density of the second sub-parts and reducing the size of each individual second sub-part, thereby reducing the introduced electrical losses.

[0033] Furthermore, the second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid, thereby making the heat flow path divergent and expanding, and the thermal resistance gradually decreases during the heat conduction process, which is conducive to the smooth diffusion of heat.

[0034] Furthermore, when the material of the first sub-part includes one of the following: glass, sapphire, quartz, spinel, and the overall thermal conductivity of the second part at room temperature is greater than 140 W / (m·K), the thermal conductivity of the second part can reach the thermal conductivity of silicon (140 W / m·K), or even the thermal conductivity of silicon carbide (300 W / m·K).

[0035] The surface acoustic wave filter device forming method provided in this embodiment of the invention introduces a second part with a higher thermal conductivity to form the hybrid part in the second part, thereby improving the overall thermal conductivity of the second part, so as to more efficiently remove heat from the first part and improve the power tolerance and reliability of the device.

[0036] Furthermore, multiple second sub-parts can be formed simultaneously with through-hole wires, thereby avoiding additional process steps. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] Figure 1 This is a schematic diagram of the heat dissipation path of a surface acoustic wave filter; Figure 2 This is a simulation diagram of the temperature distribution of a surface acoustic wave filter under operating conditions; Figure 3 This is a schematic diagram of the structure of a surface acoustic wave filter device in one embodiment of the present invention; Figures 4 to 5 This is a schematic diagram of the structure of a surface acoustic wave filter device in another embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a surface acoustic wave filter according to an embodiment of the present invention; Figures 7 to 8 This is a schematic diagram of the structure of a surface acoustic wave filter according to another embodiment of the present invention; Figure 9 This is a schematic diagram of a surface acoustic wave filter structure according to another embodiment of the present invention; Figures 10 to 11 This is a schematic diagram of a surface acoustic wave filter structure according to another embodiment of the present invention; Figure 12 This is a schematic diagram of a surface acoustic wave filter structure according to another embodiment of the present invention; Figure 13 This is a schematic flowchart of a surface acoustic wave filter fabrication method according to an embodiment of the present invention; Figure 14 yes Figure 13 The diagram shows a schematic of the surface acoustic wave filter fabricated using the method described. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein, and therefore the invention is not limited to the specific embodiments disclosed below.

[0041] During the operation of a SAW filter, an electrical signal is applied to the interdigital transducer, causing it to vibrate. This vibration excites the electromechanical coupling effect of the piezoelectric material, generating heat during the acoustic-electric energy conversion. This heat typically diffuses to the outside through the substrate portion corresponding to the interdigital transducer. For example... Figure 1 As shown, the heat dissipation path (indicated by the red arrow) must pass through the substrate and molding layer sequentially. If the substrate has a low thermal conductivity (e.g., less than 10 W / m·K), it creates significant resistance in the heat flow path. Inefficient heat dissipation prevents heat from being quickly dissipated, ultimately leading to severe heat accumulation in the region corresponding to the interdigital transducer. This concentrated heat distribution in the region can easily cause device damage or even failure. See details... Figure 2 During the operation of the SAW filter, the temperature distribution is not uniform. In the region corresponding to the interdigital transducer (the yellow and orange areas in the figure), the temperature is significantly higher than that of other regions, forming a distinct "heat island".

[0042] This invention provides a surface acoustic wave (SAW) filtering device, comprising: a substrate including a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion being located on the second portion, the thermal conductivity of the second portion being greater than that of the first portion, the first portion including the first surface, and the second portion including the second surface; a plurality of interdigitated electrodes located on the first surface; wherein the first portion includes a piezoelectric material; wherein the second portion includes a mixing portion corresponding to at least the plurality of interdigitated electrodes; wherein the mixing portion includes a plurality of first sub-parts and a plurality of second sub-parts spaced apart; wherein the thermal conductivity of the first sub-parts at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-parts; wherein the thermal conductivity of the second sub-parts at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-parts.

[0043] The present invention improves the overall thermal conductivity of the second part by introducing a second sub-part with a higher thermal conductivity into the second part to form the hybrid part, thereby enabling more efficient heat dissipation from the first part (the area below the interdigitated electrodes) and thus improving the power tolerance and reliability of the device.

[0044] Figure 3 This is a schematic diagram of the structure of a surface acoustic wave filter device according to an embodiment of the present invention. Figure 4 and Figure 5 This is a schematic diagram of the structure of a surface acoustic wave filter device in another embodiment of the present invention.

[0045] See Figure 3 The surface acoustic wave (SAW) filter device includes: a substrate 11, comprising a first surface 111 and a second surface 112 opposite to the first surface 111; wherein the substrate 11 includes a first portion 113 and a second portion 114, the first portion 113 being located on the second portion 114, the thermal conductivity of the second portion 114 being greater than that of the first portion 113, the first portion 113 including the first surface 111, and the second portion 114 including the second surface 112; a plurality of interdigitated electrodes 12 located on the first surface 111; wherein the first portion 113 comprises a piezoelectric material; wherein the second portion 114 includes a mixing portion 1141, corresponding to at least the plurality of interdigitated electrodes 12; wherein the mixing portion 1141 includes a plurality of first sub-parts 11411 and a plurality of second sub-parts 11412 spaced apart; wherein the thermal conductivity of the first sub-parts 11411 at room temperature is less than 140. W / (m·K), the second surface 112 exposes the first sub-part 11411; wherein, the second sub-part 11412 has a thermal conductivity greater than 140 W / (m·K) at room temperature, and the second surface 112 also exposes the second sub-part 11412.

[0046] In this embodiment, the first part 113 includes an intermediate layer 1131 and a piezoelectric layer 1132 located on the intermediate layer 1131, and the intermediate layer 1131 is located between the second part 114 and the piezoelectric layer 1132.

[0047] In another embodiment, see Figure 4 and Figure 5 The intermediate layer 1131 and the piezoelectric layer 1132 further include several interlayers, and the thermal conductivity of the several interlayers is similar to that of the piezoelectric layer 1132.

[0048] In this embodiment, the thermal conductivity of the intermediate layer 1131 is greater than that of the piezoelectric layer 1132, and the thermal conductivity of the intermediate layer 1131 is less than that of the second portion 114.

[0049] In this embodiment, a plurality of second sub-parts 11412 penetrate the second portion 114 and contact the intermediate layer 1131.

[0050] In this embodiment, the piezoelectric layer 1132 is made of lithium tantalate. In another embodiment, the piezoelectric layer is made of lithium niobate or zinc oxide.

[0051] In this embodiment, the thermal conductivity of the first sub-part 11411 at room temperature is less than 50 W / (m·K).

[0052] In this embodiment, the material of the first sub-part 11411 is glass. In another embodiment, the material of the first sub-part includes one of the following: sapphire, quartz, and spinel.

[0053] In this embodiment, the thermal conductivity of the second sub-part 11412 at room temperature is greater than 200 W / (m·K).

[0054] In this embodiment, the material of the second sub-part 11412 includes a metallic material; specifically, the material of the second sub-part 11412 is copper. In another embodiment, the metallic material includes one of the following: aluminum, nickel, gold, and titanium.

[0055] In another embodiment, the material of the second sub-part includes a non-metallic material, which includes one of the following: diamond, cubic boron nitride, boron arsenide, aluminum nitride, gallium nitride, and beryllium oxide. It should be noted that selecting a non-metallic material with a high thermal conductivity can improve the thermal conductivity of the second part and effectively avoid introducing parasitic capacitance, parasitic inductance, or electrostatic discharge, thereby preventing additional electrical losses.

[0056] In this embodiment, the second part 114 further includes a non-mixing portion 1142, which is offset from the plurality of interdigitated electrodes 12. The non-mixing portion 1142 has a thermal conductivity of less than 140 W / (m·K) at room temperature, and the second surface 112 exposes the non-mixing portion 1142. It should be noted that the non-mixing portion 1142 may be located in a non-heat-concentrated area such as a connecting line or solder pad.

[0057] In another embodiment, the non-mixing portion may also be located below a plurality of interdigitated electrodes.

[0058] In this embodiment, the thermal conductivity of the non-mixed portion 1142 at room temperature is less than 50 W / (m·K), and the material of the non-mixed portion 1142 is glass. In another embodiment, the material of the non-mixed portion includes one of the following: sapphire, quartz, and spinel.

[0059] In this embodiment, the intermediate layer 1131 is made of silicon nitride. In another embodiment, the intermediate layer is made of aluminum nitride or aluminum oxide.

[0060] Figure 6This is a schematic diagram of the structure of a surface acoustic wave filter according to an embodiment of the present invention. Figure 7 and Figure 8 This is a schematic diagram of the structure of a surface acoustic wave filter according to another embodiment of the present invention.

[0061] In this embodiment, see Figure 6 The multiple second sub-parts 11412 are distributed in a grid pattern.

[0062] In another embodiment, see Figure 7 The multiple second sub-parts 11412 are distributed in a high-order lattice, specifically including uniform lattice distribution or non-uniform lattice distribution.

[0063] In another embodiment, see Figure 8 The multiple second sub-parts 11412 are distributed in a high-order linear array. Specifically, the linear array distribution includes at least one of the following: horizontal lines, vertical lines, diagonal lines, arcs, curves, and broken line linear array distribution.

[0064] It should be noted that when the second sub-component is made of metal, by designing it to be distributed in a grid, high-order lattice, or high-order linear array, the distribution density of the second sub-component can be increased, the size of each individual second sub-component can be reduced, and the electrical losses introduced by parasitic capacitance, parasitic inductance, or electrostatic discharge can be reduced.

[0065] In this embodiment, the second sub-part 11412 has a rectangular short cross-section along a direction perpendicular to the substrate 11. It should be noted that the short cross-section is a section taken along the short side of the second sub-part 11412.

[0066] In another embodiment, the second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid. It should be noted that this trapezoidal cross-section design makes the heat flow path from the first part downwards divergent and expanding. The thermal resistance gradually decreases during heat conduction, which facilitates the smooth diffusion of heat to the wider second surface, further optimizing heat dissipation efficiency.

[0067] In this embodiment, the thermal conductivity of the second part 114 at room temperature is greater than 140 W / (m·K). It should be noted that when the material of the first sub-part 11411 is glass, and the overall thermal conductivity of the second part 114 at room temperature is greater than 140 W / (m·K), the thermal conductivity of the second part 114 can reach the thermal conductivity of silicon (140 W / m·K), and can even reach the thermal conductivity of silicon carbide (300 W / m·K).

[0068] In summary, by introducing a second sub-part 11412 with a higher thermal conductivity into the second part 114 to form the hybrid part 1141, the overall thermal conductivity of the second part 114 is effectively improved, enabling more efficient heat dissipation from the first part 113, thereby improving the power tolerance and reliability of the device.

[0069] Figure 9 This is a schematic diagram of the structure of a surface acoustic wave filter device in another embodiment of the present invention; Figure 10 and Figure 11 This is a schematic diagram of the structure of a surface acoustic wave filter device in another embodiment of the present invention.

[0070] See Figure 9 The surface acoustic wave (SAW) filter device includes: a substrate 21, comprising a first surface 211 and a second surface 212 opposite to the first surface 211; wherein the substrate 21 includes a first portion 213 and a second portion 214, the first portion 213 being located on the second portion 214, the thermal conductivity of the second portion 214 being greater than that of the first portion 213, the first portion 213 including the first surface 211, and the second portion 214 including the second surface 212; a plurality of interdigitated electrodes 22 located on the first surface 211; wherein the first portion 213 comprises a piezoelectric material; wherein the second portion 214 includes a mixing portion 2141 corresponding to at least a plurality of the interdigitated electrodes 22; wherein the mixing portion 2141 includes a plurality of first sub-parts 21411 and a plurality of second sub-parts 21412 spaced apart; wherein the thermal conductivity of the first sub-parts 21411 at room temperature is less than 140. W / (m·K), the second surface 212 exposes the first sub-part 21411; wherein, the second sub-part 21412 has a thermal conductivity greater than 140 W / (m·K) at room temperature, and the second surface 212 also exposes the second sub-part 21412.

[0071] In this embodiment, the second part 214 includes a substrate 2143 and an intermediate layer 2144 located on the substrate 2143, wherein the intermediate layer 2144 is located between the substrate 2143 and the first part 213.

[0072] In other embodiments, see Figure 10 and Figure 11 There may be a sandwich layer between the substrate 2143 and the intermediate layer 2144, and the thermal conductivity of the sandwich layer is similar to that of the intermediate layer 2144.

[0073] In this embodiment, the thermal conductivity of the intermediate layer 2144 is less than that of the first portion 213.

[0074] In this embodiment, the material of the first portion 213 is lithium tantalate. In another embodiment, the material of the first portion includes lithium niobate or zinc oxide.

[0075] In this embodiment, the intermediate layer 2144 is made of silicon dioxide. In another embodiment, the intermediate layer is made of silicon oxynitride.

[0076] In this embodiment, the substrate 2143 is made of glass. In another embodiment, the substrate is made of one of the following materials: sapphire, quartz, or spinel.

[0077] In this embodiment, a plurality of second sub-parts 21412 penetrate the second portion 214 and contact the first portion 213.

[0078] In this embodiment, the thermal conductivity of the first sub-part 21411 at room temperature is less than 50 W / (m·K).

[0079] In this embodiment, the material of the first sub-part 21411 includes glass. In another embodiment, the material of the first sub-part includes one of the following: sapphire, quartz, and spinel.

[0080] In this embodiment, the thermal conductivity of the second sub-part 21412 at room temperature is greater than 200 W / (m·K).

[0081] In this embodiment, the material of the second sub-part 21412 includes a metallic material; specifically, the metallic material is copper. In another embodiment, the metallic material includes one of the following: aluminum, nickel, gold, and titanium.

[0082] In another embodiment, the material of the second sub-part includes a non-metallic material, which includes one of the following: diamond, cubic boron nitride, boron arsenide, aluminum nitride, gallium nitride, and beryllium oxide. It should be noted that selecting a non-metallic material with a high thermal conductivity can improve the thermal conductivity of the second part and effectively avoid introducing parasitic capacitance, parasitic inductance, or electrostatic discharge, thereby preventing additional electrical losses.

[0083] In this embodiment, the second part 214 further includes a non-mixing portion 2142, which is offset from the plurality of interdigitated electrodes 22; wherein, the thermal conductivity of the non-mixing portion 2142 at room temperature is less than 140 W / (m·K), and the second surface 212 exposes the non-mixing portion 2142. It should be noted that the non-mixing portion 2142 may be located in a non-heat-concentrated area such as a connecting line or pad.

[0084] In another embodiment, the non-mixing portion may also be located below a plurality of interdigitated electrodes.

[0085] In this embodiment, the thermal conductivity of the non-mixing part 2142 at room temperature is less than 50 W / (m·K).

[0086] In this embodiment, the material of the non-mixed portion 2142 includes glass. In another embodiment, the material of the non-mixed portion 2142 includes one of the following: sapphire, quartz, or spinel.

[0087] In this embodiment, the plurality of second sub-parts 21412 are arranged in a grid.

[0088] In another embodiment, the plurality of second sub-parts are distributed in a high-order lattice or a high-order linear array.

[0089] In this embodiment, the second sub-part 21412 has a rectangular short cross-section along a direction perpendicular to the substrate 21. It should be noted that the short cross-section is a section taken along the short side of the second sub-part 21412.

[0090] In another embodiment, the second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid. It should be noted that this trapezoidal cross-section design makes the heat flow path from the first part downwards divergent and expanding. The thermal resistance gradually decreases during heat conduction, which facilitates the smooth diffusion of heat to the wider second surface, further optimizing heat dissipation efficiency.

[0091] In this embodiment, the thermal conductivity of the second portion 214 at room temperature is greater than 140 W / (m·K). It should be noted that when the material of the first sub-part 21411 includes glass, and the overall thermal conductivity of the second portion 214 at room temperature is greater than 140 W / (m·K), the thermal conductivity of the second portion 214 can reach that of silicon (140 W / m·K), and may even reach that of silicon carbide (300 W / m·K).

[0092] In summary, by introducing a second sub-part 21412 with a higher thermal conductivity into the second part 214 to form the hybrid part 2141, the overall thermal conductivity of the second part 214 is effectively improved, enabling more efficient heat dissipation from the first part 213, thereby improving the power tolerance and reliability of the device.

[0093] Figure 12 This is a schematic diagram of the structure of a surface acoustic wave filter device in another embodiment of the present invention.

[0094] See Figure 12The surface acoustic wave (SAW) filter includes: a substrate 31, comprising a first surface 311 and a second surface 312 opposite to the first surface 311; wherein the substrate 31 includes a first portion 313 and a second portion 314, the first portion 313 being located on the second portion 314, the thermal conductivity of the second portion 314 being greater than that of the first portion 313, the first portion 313 including the first surface 311, and the second portion 314 including the second surface 312; a plurality of interdigitated electrodes 32 located on the first surface 311; wherein the first portion 313 comprises a piezoelectric material; wherein the second portion 314 includes a mixing portion 3141 corresponding to at least a plurality of the interdigitated electrodes 32; wherein the mixing portion 3141 includes a plurality of first sub-parts 31411 and a plurality of second sub-parts 31412 spaced apart; wherein the thermal conductivity of the first sub-parts 31411 at room temperature is less than 140. W / (m·K), the second surface 312 exposes the first sub-part 31411; wherein, the second sub-part 31412 has a thermal conductivity greater than 140 W / (m·K) at room temperature, and the second surface 312 also exposes the second sub-part 31412.

[0095] In this embodiment, the second part 314 includes the piezoelectric material; wherein, the first sub-part 31411 includes the piezoelectric material.

[0096] In this embodiment, the piezoelectric material is lithium tantalate. In another embodiment, the piezoelectric material includes lithium niobate or zinc oxide.

[0097] In this embodiment, a plurality of second sub-parts 31412 penetrate the second portion 314 and contact the first portion 313.

[0098] In this embodiment, the thickness of the first portion 313 ranges from 0.05λ to λ; where λ is the wavelength of the acoustic wave generated by the excitation.

[0099] In this embodiment, the thermal conductivity of the first sub-part 31411 at room temperature is less than 50 W / (m·K).

[0100] In this embodiment, the material of the first sub-part 31411 is lithium tantalate. In another embodiment, the material of the first sub-part includes lithium niobate or zinc oxide.

[0101] In this embodiment, the thermal conductivity of the second sub-part 31412 at room temperature is greater than 200 W / (m·K).

[0102] In this embodiment, the material of the second sub-part 31412 includes a metallic material; specifically, the material of the second sub-part 31412 is copper. In another embodiment, the metallic material includes one of the following: aluminum, nickel, gold, and titanium.

[0103] In another embodiment, the material of the second sub-part includes a non-metallic material, which includes one of the following: diamond, cubic boron nitride, boron arsenide, aluminum nitride, gallium nitride, and beryllium oxide. It should be noted that selecting a non-metallic material with a high thermal conductivity can improve the thermal conductivity of the second part and effectively avoid introducing parasitic capacitance, parasitic inductance, or electrostatic discharge, thereby preventing additional electrical losses.

[0104] In this embodiment, the second part 314 further includes a non-mixing portion 3142, which is offset from the plurality of interdigitated electrodes 32; wherein, the thermal conductivity of the non-mixing portion 3142 at room temperature is less than 140 W / (m·K), and the second surface 312 exposes the non-mixing portion 3142. It should be noted that the non-mixing portion 3142 may be located in a non-heat-concentrated area such as a connecting line or pad.

[0105] In another embodiment, the non-mixing portion may also be located below a plurality of interdigitated electrodes.

[0106] In this embodiment, the thermal conductivity of the non-mixing part 3142 at room temperature is less than 50 W / (m·K).

[0107] In this embodiment, the material of the non-mixed portion 3142 is lithium tantalate. In another embodiment, the material of the non-mixed portion includes one of the following: lithium niobate, zinc oxide.

[0108] In this embodiment, the plurality of second sub-parts 31412 are arranged in a grid.

[0109] In another embodiment, the plurality of second sub-parts are distributed in a high-order lattice or a high-order linear array.

[0110] It should be noted that when the second sub-component is made of metal, by designing it to be distributed in a grid, high-order lattice, or high-order linear array, the distribution density of the second sub-component can be increased, the size of each individual second sub-component can be reduced, and the electrical losses introduced by parasitic capacitance, parasitic inductance, or electrostatic discharge can be reduced.

[0111] In this embodiment, the second sub-part 31412 has a rectangular short cross-section along a direction perpendicular to the substrate 31. It should be noted that the short cross-section is a cross-section taken along the short side of the second sub-part 31412.

[0112] In another embodiment, the second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid. It should be noted that this trapezoidal cross-section design makes the heat flow path from the first part downwards divergent and expanding. The thermal resistance gradually decreases during heat conduction, which facilitates the smooth diffusion of heat to the wider second surface, further optimizing heat dissipation efficiency.

[0113] In this embodiment, the thermal conductivity of the second part 314 at room temperature is greater than 140 W / (m·K). It should be noted that when the material of the first sub-part 31411 is lithium tantalate, and the overall thermal conductivity of the second part 314 at room temperature is greater than 140 W / (m·K), the thermal conductivity of the second part 314 can reach the thermal conductivity of silicon (140 W / m·K), and can even reach the thermal conductivity of silicon carbide (300 W / m·K).

[0114] In summary, by introducing a second sub-part 31412 with a higher thermal conductivity into the second part 314 to form the hybrid part 3141, the overall thermal conductivity of the second part 314 is effectively improved, enabling more efficient heat dissipation from the first part 313, thereby improving the power tolerance and reliability of the device.

[0115] This invention provides a duplexer, including a first filtering device for transmitting electrical signals, wherein the first filtering device is a surface acoustic wave (SAW) filtering device as described in any of the above embodiments. In this embodiment, the duplexer further includes a second filtering device for receiving electrical signals, wherein the second filtering device is also a SAW filtering device as described in any of the above embodiments.

[0116] Figure 13 This is a flowchart of a method for forming a surface acoustic wave filter according to an embodiment of the present invention.

[0117] This invention provides a method 400 for forming a surface acoustic wave (SAW) filter device, comprising: Step 401: Forming a substrate, including a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion being located on the second portion, the thermal conductivity of the second portion being greater than that of the first portion, the first portion including the first surface, and the second portion including the second surface; wherein the first portion includes a piezoelectric material; wherein the second portion includes a mixing portion, the mixing portion including a plurality of first sub-parts and a plurality of second sub-parts spaced apart; wherein the thermal conductivity of the first sub-parts at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-parts; wherein the thermal conductivity of the second sub-parts at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-parts; Step 403: Form a plurality of interdigitated electrodes located on the first surface, wherein the mixing portion corresponds to at least a plurality of the interdigitated electrodes; Step 401 includes: Step 4011: Provide a substrate; based on the substrate, form a substrate by semiconductor processing; wherein the semiconductor processing includes at least one of the following: cleaning, planarization, bonding, and thinning; Step 4013: Form a through-hole that penetrates the substrate; form a connecting line in the through-hole for electrically connecting the interdigitated electrodes; wherein the connecting line is formed synchronously with the second sub-part.

[0118] In this embodiment, the second part further includes a non-mixing portion, which is staggered from the plurality of interdigitated electrodes; wherein the thermal conductivity of the non-mixing portion at room temperature is less than 140 W / (m·K), and the second surface exposes the non-mixing portion.

[0119] In this embodiment, the plurality of second sub-parts are arranged in a grid pattern. In another embodiment, the plurality of second sub-parts are arranged in a high-order lattice pattern or a high-order linear array pattern.

[0120] In this embodiment, forming a substrate based on the substrate using semiconductor processing includes: forming a piezoelectric layer; forming an intermediate layer located on the piezoelectric layer or the substrate; and correspondingly bonding the intermediate layer to the substrate or the piezoelectric layer, wherein the intermediate layer is located between the substrate and the piezoelectric layer. In another embodiment, forming a substrate based on the substrate using semiconductor processing includes: planarizing and cleaning the surface of the substrate.

[0121] The surface acoustic wave filter device forming method provided in this embodiment of the invention introduces a second part with a higher thermal conductivity to form the hybrid part in the second part, thereby improving the overall thermal conductivity of the second part, so as to more efficiently remove heat from the first part and improve the power tolerance and reliability of the device.

[0122] Furthermore, multiple second sub-parts can be formed simultaneously with through-hole wires, thereby avoiding additional process steps.

[0123] Figure 14 This is a schematic diagram of the structure of a surface acoustic wave filter prepared by the formation method of this invention.

[0124] See Figure 14 The blue dashed box B indicates the location of the connecting lines, whose main function is to achieve electrical interconnection between the interdigital electrodes and external circuits. These connecting lines are typically filled in through-holes penetrating the substrate and are made of highly conductive metal to ensure low-loss signal transmission. Their fabrication process is synchronized with the second sub-section in the hybrid section, avoiding additional process steps. The red dashed box A indicates the location of the hybrid section, situated between the two sets of blue dashed box B areas. Its core function is efficient heat dissipation. This area introduces the second sub-section with a higher thermal conductivity to form the hybrid section, thereby effectively improving the overall thermal conductivity of the second part. This allows for more efficient heat dissipation from the first part, thus improving the device's power tolerance and reliability.

[0125] The above description is illustrative only and not restrictive of the present invention. Those skilled in the art will understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined by the appended claims, and all such modifications, variations or equivalents will fall within the protection scope of the present invention.

Claims

1. A surface acoustic wave (SAW) filtering device, characterized in that, include: A substrate includes a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion being located on the second portion, the thermal conductivity of the second portion being greater than that of the first portion, the first portion including the first surface, and the second portion including the second surface; Multiple interdigitated electrodes are located on the first surface; The first part includes a piezoelectric material; The second part includes a mixing section corresponding to at least a plurality of interdigitated electrodes; wherein the mixing section includes a plurality of first sub-sections and a plurality of second sub-sections spaced apart; wherein the thermal conductivity of the first sub-section at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-section; wherein the thermal conductivity of the second sub-section at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-section.

2. The surface acoustic wave filter according to claim 1, characterized in that, The thermal conductivity of the first sub-component at room temperature is less than 50 W / (m·K).

3. The surface acoustic wave filter according to claim 2, characterized in that, The material of the first sub-component includes one of the following: lithium tantalate, lithium niobate, zinc oxide, glass, sapphire, quartz, spinel.

4. The surface acoustic wave filter according to claim 1, characterized in that, The thermal conductivity of the second sub-component at room temperature is greater than 200 W / (m·K).

5. The surface acoustic wave filter according to claim 4, characterized in that, The material of the second sub-part includes a metallic material; wherein the metallic material includes one of the following: aluminum, copper, nickel, gold, and titanium.

6. The surface acoustic wave filter according to claim 4, characterized in that, The material of the second sub-part includes non-metallic materials; wherein the non-metallic materials include one of the following: diamond, cubic boron nitride, boron arsenide, aluminum nitride, gallium nitride, and beryllium oxide.

7. The surface acoustic wave filter according to claim 1, characterized in that, The second part further includes a non-mixing portion, which is offset from the plurality of interdigitated electrodes; wherein the thermal conductivity of the non-mixing portion at room temperature is less than 140 W / (m·K), and the second surface exposes the non-mixing portion.

8. The surface acoustic wave filter according to claim 7, characterized in that, The thermal conductivity of the unmixed part at room temperature is less than 50 W / (m·K).

9. The surface acoustic wave filter according to claim 8, characterized in that, The material of the non-mixed part includes one of the following: lithium tantalate, lithium niobate, zinc oxide, glass, sapphire, quartz, spinel.

10. The surface acoustic wave filtering device according to claim 1, characterized in that, Multiple second sub-parts are distributed in a lattice, a linear array, or a grid.

11. The surface acoustic wave filter according to claim 1, characterized in that, The second sub-part has a rectangular or trapezoidal short cross-section perpendicular to the substrate.

12. The surface acoustic wave filter according to claim 11, characterized in that, The second sub-part has a trapezoidal short cross-section perpendicular to the substrate, and the second surface exposes the bottom surface of the second sub-part corresponding to the long base of the trapezoid.

13. The surface acoustic wave filter according to claim 1, characterized in that, The second portion includes the piezoelectric material; wherein the first sub-portion includes the piezoelectric material; wherein the piezoelectric material includes one of the following: lithium tantalate, lithium niobate, and zinc oxide; wherein the second sub-portion penetrates the second portion and contacts the first portion.

14. The surface acoustic wave filter according to claim 13, characterized in that, The thickness of the first portion ranges from 0.05λ to λ, where λ is the wavelength of the acoustic wave generated by the excitation.

15. The surface acoustic wave filter according to claim 1, characterized in that, The first portion includes an intermediate layer and a piezoelectric layer located on the intermediate layer, the intermediate layer being located between the second portion and the piezoelectric layer; wherein the material of the piezoelectric layer includes one of the following: lithium tantalate, lithium niobate, and zinc oxide; wherein the thermal conductivity of the intermediate layer is greater than that of the piezoelectric layer, and the thermal conductivity of the intermediate layer is less than that of the second portion; wherein a plurality of second sub-parts penetrate the second portion and contact the intermediate layer.

16. The surface acoustic wave filter according to claim 15, characterized in that, The intermediate layer is made of aluminum nitride, silicon nitride, or aluminum oxide; the first sub-part is made of one of the following: glass, sapphire, quartz, or spinel.

17. The surface acoustic wave filter according to claim 1, characterized in that, The second part includes a substrate and an intermediate layer located on the substrate, the intermediate layer being located between the substrate and the first part, the thermal conductivity of the intermediate layer being less than that of the first part; wherein the material of the first part includes one of the following: lithium tantalate, lithium niobate, zinc oxide; wherein a plurality of second sub-parts penetrate the second part and contact the first part.

18. The surface acoustic wave filter according to claim 17, characterized in that, The intermediate layer is made of silicon dioxide or silicon oxynitride; the substrate is made of one of the following: glass, sapphire, quartz, or spinel.

19. The surface acoustic wave filter according to claim 1, characterized in that, The thermal conductivity of the second part at room temperature is greater than 140 W / (m·K).

20. A duplexer, characterized in that, include: A first filtering device is used to transmit electrical signals, wherein the first filtering device is a surface acoustic wave filtering device according to any one of claims 1 to 19.

21. The duplexer according to claim 20, characterized in that, Also includes: The second filtering device is used to receive electrical signals, and the second filtering device is a surface acoustic wave filtering device according to any one of claims 1 to 19.

22. A method for forming a surface acoustic wave filter, characterized in that, include: A substrate is formed, including a first surface and a second surface opposite to the first surface; wherein the substrate includes a first portion and a second portion, the first portion is located on the second portion, the thermal conductivity of the second portion is greater than that of the first portion, the first portion includes the first surface, and the second portion includes the second surface; Multiple interdigitated electrodes are formed on the first surface; The first part includes a piezoelectric material; The second part includes a mixing section corresponding to at least a plurality of interdigitated electrodes; wherein the mixing section includes a plurality of first sub-sections and a plurality of second sub-sections spaced apart; wherein the thermal conductivity of the first sub-section at room temperature is less than 140 W / (m·K), and the second surface exposes the first sub-section; wherein the thermal conductivity of the second sub-section at room temperature is greater than 140 W / (m·K), and the second surface also exposes the second sub-section.

23. The method according to claim 22, characterized in that, The second part further includes a non-mixing portion, which is offset from the plurality of interdigitated electrodes; wherein the thermal conductivity of the non-mixing portion at room temperature is less than 140 W / (m·K), and the second surface exposes the non-mixing portion.

24. The method according to claim 22, characterized in that, Multiple second sub-parts are distributed in a lattice, a linear array, or a grid.

25. The method according to claim 22, characterized in that, The substrate formation further includes: forming a through-hole that penetrates the substrate; forming a connecting line located in the through-hole for electrically connecting the interdigitated electrodes; wherein the connecting line is formed synchronously with the second sub-part.

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