Surface acoustic wave device and method of manufacturing the same

Abstract

The present application relates to the technical field of semiconductor, in particular to a surface acoustic wave device and a preparation method thereof.The surface acoustic wave device comprises a substrate, a pad, an interdigital transducer, a heat-conducting metal structure and a heat-dissipating metal layer;the substrate has opposite first and second surfaces along the thickness direction of the substrate;the pad and the interdigital transducer are both arranged on the first surface;the pad is connected with the interdigital transducer through a metal wiring structure;the interdigital transducers are connected through the metal wiring structure;the heat-dissipating metal layer is arranged on the second surface;one end of the heat-conducting metal structure is arranged on the first surface, and the other end is connected with the heat-dissipating metal layer;the heat-conducting metal structure does not contact the interdigital transducer.In this way, the heat-conducting metal is connected with the heat-dissipating metal to lead the heat of the chip surface area to the back of the chip, increase the heat-dissipating area and enhance the heat-dissipating capacity of the product.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a surface acoustic wave device and its fabrication method. Background Technology

[0002] SAW filters, due to their superior performance, meet the requirements of modern communication systems and portable telephones for miniaturization, high performance, and high reliability. Furthermore, their design flexibility makes them well-suited for mid-to-low frequency bands, resulting in a promising market prospect. As product sizes trend towards smaller dimensions, higher demands are placed on product design. Especially with the reduction in device size and the centralization of circuit design, localized heat generation on the product surface during operation can be significant (the main operating circuitry of SAW filters is concentrated on the wafer surface). If heat dissipation is not timely, the electrodes may burn out, leading to product malfunction. Summary of the Invention

[0003] The present invention aims to provide, for example, a surface acoustic wave device and its fabrication method, which can connect a thermally conductive metal to a heat-dissipating metal to conduct heat from the surface area of ​​the chip to the back of the chip, thereby increasing the heat dissipation area and enhancing the heat dissipation capability of the product.

[0004] The embodiments of the present invention can be implemented as follows:

[0005] In a first aspect, the present invention provides a surface acoustic wave device, comprising:

[0006] Substrate, pads, interdigital transducers, thermally conductive metal structures, and heat-dissipating metal layers;

[0007] Along the thickness direction of the substrate, the substrate has opposing first and second surfaces;

[0008] The pads and the interdigital transducers are both disposed on the first surface; the pads and the interdigital transducers are connected by a metal wiring structure; the interdigital transducers are connected to each other by a metal wiring structure.

[0009] The heat dissipation metal layer is disposed on the second surface; one end of the heat-conducting metal structure is disposed on the first surface, and the other end is connected to the heat dissipation metal layer; the heat-conducting metal structure does not contact the interdigital transducer.

[0010] In an optional embodiment, the thermally conductive metal structure includes a horizontal section and a vertical section;

[0011] The horizontal segment is disposed on the first surface;

[0012] One end of the vertical segment is connected to the end of the horizontal segment, and the other end of the vertical segment extends along the thickness direction of the substrate to the heat dissipation metal layer.

[0013] In an optional embodiment, a through hole is formed on the substrate along the thickness direction; the vertical segment passes through the through hole and is connected to the heat dissipation metal layer.

[0014] In an optional embodiment, the thermally conductive metal structure is disposed in the through hole by means of a metal coating.

[0015] In an optional embodiment, the through hole extends from the first surface to the second surface;

[0016] Along the length of the substrate, the diameter of the via is 5 micrometers to 50 micrometers;

[0017] Along the width direction of the substrate, the aperture of the via is 3 micrometers to 30 micrometers.

[0018] In an optional embodiment, the horizontal segment is disposed at a preset position on the first surface; the preset position is configured as the area on the first surface with the highest temperature when the surface acoustic wave device is in operation.

[0019] In an optional implementation, the lateral dimension of the horizontal segment is 5 micrometers to 50 micrometers.

[0020] In an optional embodiment, the thickness of the heat-dissipating metal layer is 0.5 micrometers to 5 micrometers.

[0021] In an optional embodiment, the heat dissipation metal layer is made of copper or stainless steel.

[0022] In an optional implementation, a plurality of bumps are also included, all of which are disposed on the first surface; the pads are disposed on the first surface via the bumps.

[0023] In optional embodiments, a packaging substrate and a molding structure are also included;

[0024] The packaging substrate is located on the side facing the first surface of the substrate, and the packaging substrate maintains a distance from the first surface of the substrate;

[0025] Along the periphery of the substrate, the molding compound is enclosed around the periphery of the substrate; along the thickness of the substrate, one side of the molding compound is bonded to one side of the encapsulation substrate; the first surface of the substrate, the top surface of the encapsulation substrate, and the inner wall of the molding compound together enclose a sealed receiving cavity; the pads, the interdigital transducers, and the thermally conductive metal structure of the first surface are located in the receiving cavity.

[0026] In an optional embodiment, the thermally conductive metal structure includes an interconnected bottom layer and a top layer; the bottom layer is made of titanium, and the top layer is made of copper, an aluminum-copper alloy, or aluminum.

[0027] In an optional embodiment, the interdigital transducer is composed of two sets of interdigital electrodes arranged in an alternating pattern; the interdigital electrodes are made of aluminum or an aluminum-copper alloy.

[0028] In a second aspect, the present invention provides a preparation method for preparing the surface acoustic wave device described in any of the foregoing embodiments; the preparation method includes:

[0029] A thermally conductive metal structure extending from the first surface to the second surface is disposed on the substrate;

[0030] The heat dissipation metal layer is disposed on the second surface, and the thermally conductive metal structure is connected to the heat dissipation metal layer.

[0031] In an optional embodiment, a through-hole is formed on the substrate, the through-hole extending from the first surface to the second surface; a metal coating is applied in the through-hole to form a vertical segment of the thermally conductive metal structure.

[0032] In an optional embodiment, the heat-dissipating metal layer is deposited on the second surface using a sputtering process.

[0033] The beneficial effects of the embodiments of the present invention include, for example:

[0034] The surface acoustic wave (SAW) device in this solution includes a substrate, pads, interdigital transducers, a thermally conductive metal structure, and a heat-dissipating metal layer. The pads and interdigital transducers are located on the first surface of the substrate, which is the primary operating area and therefore the area generating the most heat during chip operation. One end of the thermally conductive metal structure is located on the first surface, and the other end extends to the second surface and connects to the heat-dissipating metal layer. This allows for efficient and timely heat transfer from the first surface to the heat-dissipating metal layer, facilitating timely heat dissipation. Furthermore, because the second surface only has the heat-dissipating metal layer and no other structures occupying it, the larger surface area provides better heat dissipation, thus improving the product's power handling capacity. Compared to existing technologies with smaller device sizes and more centralized circuit designs, where localized surface heat is high during operation and cannot be dissipated in time, potentially leading to electrode burnout and product failure, this solution combines the advantages of integration and miniaturization with improved heat dissipation capabilities, ensuring the stability and reliability of the device. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure on the substrate of the surface acoustic wave device according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the surface acoustic wave device from another perspective according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of process 1 of the fabrication method of the surface acoustic wave device according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of process 2 of the fabrication method of the surface acoustic wave device according to an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of process 3 of the fabrication method of the surface acoustic wave device according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of process 4 of the fabrication method of the surface acoustic wave device according to an embodiment of the present invention.

[0042] Icons: 11-Pad; 12-Heat dissipation metal layer; 13-Metal wiring structure; 14-Bump; 15-Packaging substrate; 16-Molding structure; 100-Substrate; 101-Through hole; 110-First surface; 120-Second surface; 300-Interdigital transducer; 310-Interdigital electrode; 400-Heat-conducting metal structure; 410-Horizontal segment; 420-Vertical segment; 500-Accommodation cavity; A-Thickness direction of substrate; B-Length direction of substrate; C-Width direction of substrate. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, 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 invention.

[0047] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0048] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0049] Please refer to Figure 1 and Figure 2 This embodiment provides a surface acoustic wave device, including a substrate 100, a pad 11, an interdigital transducer 300, a thermally conductive metal structure 400, and a heat dissipation metal layer 12;

[0050] Along the thickness direction A of the substrate, the substrate 100 has a first surface 110 and a second surface 120 opposite to each other;

[0051] The pads 11 and the interdigital transducers 300 are both disposed on the first surface 110; the pads 11 and the interdigital transducers 300 are connected by a metal wiring structure 13; the interdigital transducers 300 are connected to each other by a metal wiring structure 13.

[0052] The heat dissipation metal layer 12 is disposed on the second surface 120; one end of the heat-conducting metal structure 400 is disposed on the first surface 110, and the other end is connected to the heat dissipation metal layer 12; the heat-conducting metal structure 400 does not contact the interdigital transducer 300.

[0053] The surface acoustic wave (SAW) device of this solution includes a substrate 100, pads 11, interdigital transducers 300, a thermally conductive metal structure 400, and a heat-dissipating metal layer 12. The pads 11 and interdigital transducers 300 are both disposed on the first surface 110 of the substrate 100, which is the main operating area of ​​the component and therefore the area where the chip accumulates the most heat. One end of the thermally conductive metal structure 400 is disposed on the first surface 110, and the other end extends to the second surface 120 and connects to the heat-dissipating metal layer 12. This allows for timely and efficient heat transfer from the first surface 110 to the heat-dissipating metal layer 12, thus facilitating timely heat dissipation. Furthermore, because the second surface 120 only has the heat-dissipating metal layer 12 and no other structures occupying it, the larger surface area provides better heat dissipation, thereby facilitating the timely removal of internal heat and improving the product's power tolerance. Compared to existing technologies that feature smaller device sizes and more centralized circuit designs, which result in higher localized heat on the surface of the product during operation and cannot dissipate heat in time, potentially leading to electrode burnout and product malfunction, this solution combines the advantages of integration and miniaturization with improved heat dissipation capabilities, ensuring the stability and reliability of the device's operation.

[0054] It should be noted that the interdigital transducer 300 (IDT) has two sets of staggered interdigital electrodes 310, which are used to achieve acoustic-to-electrical energy conversion. The IDT is the most basic unit constituting a surface acoustic wave device. The substrate 100 is a piezoelectric substrate. The thermally conductive metal structure 400 is used to conduct heat from the chip to the heat dissipation metal layer 12.

[0055] In an optional embodiment, the interdigital transducer 300 is composed of two sets of staggered interdigital electrodes 310; the interdigital electrodes 310 are made of aluminum or an aluminum-copper alloy. That is, the interdigital electrodes 310 can be made of aluminum or an aluminum-copper alloy. This ensures the working performance of the interdigital transducer 300.

[0056] In optional embodiments, the thermally conductive metal structure 400 includes an interconnected bottom layer and a top layer; the bottom layer is made of titanium, and the top layer is made of copper, an aluminum-copper alloy, or aluminum. This structure ensures that the thermally conductive metal structure 400 has excellent structural performance while also having good thermal conductivity, thereby facilitating the timely conduction and dissipation of temperature in the working area of ​​the first surface 110.

[0057] In an optional embodiment, the thickness of the heat-dissipating metal layer 12 is 0.5 micrometers to 5 micrometers. The heat-dissipating metal layer 12 is made of copper or stainless steel. The copper or stainless steel heat-dissipating metal layer 12 has excellent heat dissipation performance.

[0058] As can be seen from the figure, the surface acoustic wave device also includes multiple bumps 14, all of which are disposed on the first surface 110; the pads 11 are disposed on the first surface 110 through the bumps 14.

[0059] Optionally, the bump 14 can be a gold ball or a solder ball, both of which are disposed on the first surface 110 and connected to the packaging substrate 15; one end of the thermally conductive metal structure 400 is disposed on the first surface 110.

[0060] The surface acoustic wave device also includes a packaging substrate 15 and a molding structure 16; the packaging substrate 15 is located on the side facing the first surface 110 of the substrate 100, and the packaging substrate 15 and the first surface 110 of the substrate 100 are kept at a distance.

[0061] Along the periphery of the substrate 100, the molding structure 16 surrounds the periphery of the substrate 100; along the thickness direction A of the substrate, one side of the molding structure 16 encapsulates one side of the substrate 15; the first surface 110 of the substrate 100, the top surface of the encapsulation substrate 15 and the inner wall of the molding structure 16 together enclose to form a sealed receiving cavity 500; the pad 11, the interdigital transducer 300 and the thermally conductive metal structure 400 of the first surface 110 are located in the receiving cavity 500.

[0062] The packaging substrate 15 is used to support the chip, ensuring the structural stability and reliability of the entire device. The molding structure 16 supports the heat dissipation metal layer 12 and the packaging substrate 15, and also provides a seal for the entire device, thereby improving the service life of the surface acoustic wave device.

[0063] from Figure 1 and Figure 2 It can also be seen that, in an optional embodiment, the thermally conductive metal structure 400 includes a horizontal segment 410 and a vertical segment 420; the horizontal segment 410 is disposed on the first surface 110; one end of the vertical segment 420 is connected to the end of the horizontal segment 410, and the other end of the vertical segment 420 extends along the thickness direction A of the substrate to the heat dissipation metal layer 12.

[0064] This thermally conductive metal structure 400 reduces its space occupation within the device and provides better thermal conductivity while avoiding interference with other components. Optionally, the horizontal segment 410 and the vertical segment 420 are perpendicular to each other. This further reduces the path length of the thermally conductive metal structure 400.

[0065] Furthermore, in an optional embodiment, a through-hole 101 is formed on the substrate 100 along the thickness direction A of the substrate; the vertical segment 420 passes through the through-hole 101 and is connected to the heat dissipation metal layer 12. This allows the chip to have a larger working area while shortening the size of the heat-conducting metal structure 400 to reduce the heat conduction path, thereby improving the efficiency of heat conduction and heat dissipation, and thus enabling the surface acoustic wave device to have excellent heat dissipation performance.

[0066] In an optional embodiment, the thermally conductive metal structure 400 is disposed in the through-hole 101 by means of metal plating. Optionally, the through-hole 101 is formed by laser drilling through the device, and then a film is applied to the back of the wafer to protect the thermally conductive metal plating in the pre-reserved area on the front drilling area and the surface of the pad 11, thereby forming the thermally conductive metal structure 400.

[0067] Please continue reading. Figure 1 and Figure 2 Optionally, in this embodiment, the through-hole 101 extends from the first surface 110 to the second surface 120; along the length direction B of the substrate, the aperture of the through-hole 101 is 5 micrometers to 50 micrometers; along the width direction C of the substrate, the aperture of the through-hole 101 is 3 micrometers to 30 micrometers. Optionally, the shape of the through-hole 101 can be circular, square, etc., and is not limited here.

[0068] It should be noted that, in an optional embodiment, the horizontal segment 410 is disposed at a preset position on the first surface 110; the preset position is configured as the area with the highest temperature on the first surface 110 when the surface acoustic wave device is in operation.

[0069] Furthermore, in an optional embodiment, the lateral dimension of the horizontal segment 410 is 5 micrometers to 50 micrometers. That is, the length of the horizontal segment 410 along the length direction B of the substrate is 5 micrometers to 50 micrometers.

[0070] The piezoelectric substrate 100 of such a surface acoustic wave device generates a piezoelectric effect; the pads 11 are connected to the metal wiring; the pads 11 are connected to the interdigital transducer 300 through the metal wiring; the interdigital transducer 300 realizes the acoustic-electric conversion; the thermally conductive metal structure 400 conducts heat on the chip; the bumps 14 lead out the circuit and are connected to the packaging substrate 15; the plastic encapsulation structure 16 wraps the chip to protect it from external environmental interference; the heat dissipation metal layer 12 dissipates heat and cools down; the packaging substrate 15 carries the chip, and by connecting the thermally conductive metal and the heat dissipation metal layer 12, the heat of the chip surface area is conducted to the back of the chip, increasing the heat dissipation area. On the one hand, this enhances the heat dissipation capacity of the chip product, and on the other hand, it can effectively reduce the size of the product.

[0071] In a second aspect, the present invention provides a preparation method for preparing a surface acoustic wave device according to any of the foregoing embodiments; the preparation method includes:

[0072] A thermally conductive metal structure 400 is provided on the substrate 100, extending from the first surface 110 to the second surface 120;

[0073] A heat dissipation metal layer 12 is provided on the second surface 120, and the heat-conducting metal structure 400 is connected to the heat dissipation metal layer 12.

[0074] In an optional embodiment, a through-hole 101 is formed on the substrate 100, extending from the first surface 110 to the second surface 120; a vertical segment 420 of the thermally conductive metal structure 400 is formed in the through-hole 101 by metal plating. Optionally, a heat-dissipating metal layer 12 is disposed on the second surface 120 by sputtering.

[0075] Please see Figures 3 to 6 The specific process of the preparation method can be as follows:

[0076] Process 1: Figure 3 As shown, firstly, photoresist is applied to the surface of substrate 100 for exposure and development. The areas where the interdigital transducer 300 is not needed are protected with photoresist. Then, photoresist coating, exposure, development, and film deposition processes are performed to form the interdigital transducer 300 (see process 1 for details). The interdigital electrodes 310 in the interdigital transducer 300 are made of pure aluminum or aluminum-copper alloy. This process is repeated to form a frequency modulation protection layer on the interdigital transducer 300.

[0077] Process 2: such as Figure 4 As shown, after process 1, photoresist is applied, exposed, and developed on the first surface 110 of the substrate 100. The pads 11 are then formed through photolithography, development, and film deposition. The materials used to construct the pads 11 include aluminum, aluminum-copper, or gold.

[0078] Process 3: such as Figure 5 As shown, after process 2, photoresist is applied, exposed, and developed on the first surface 110 of the substrate 100. The laser-drilled hole 101 area and the thermally conductive metal structure 400 area are reserved through photolithography, development, and laser drilling. Then, through holes 101 are pre-drilled on the substrate 100 by laser drilling. Then, a protective film is attached to the back of the wafer. The thermally conductive metal structure 400 is deposited in the area of ​​the through hole 101 on the first surface 110 and the reserved area on the surface of the pad 11 (the bottom material of the thermally conductive metal structure 400 is Ti and the surface material is Cu).

[0079] Process 4: Figure 6As shown, after process 3, balls are placed at the window position of pad 11 (i.e., bumps 14 are set), and then the wafer dicing, flip-chip bonding, molding, baking and other processes are completed by normal CSP (Chip Scale Package) process. After baking, the entire substrate molding surface is thinned to expose the second surface 120 of the piezoelectric substrate 100. A heat dissipation metal layer 12 is formed on the second surface 120 by sputtering process to finally form a complete heat dissipation path, ensuring that the heat on the chip surface can be guided to the back of the chip and dissipated in time (the material of the heat dissipation metal layer 12 is Cu or stainless steel).

[0080] In summary, the embodiments of the present invention provide a surface acoustic wave device and its fabrication method, which have at least the following advantages:

[0081] 1. By improving the product's heat dissipation capacity, the product's power tolerance can be increased, thereby improving the product's reliability.

[0082] 2. It can also reduce the overall thickness of the product, making it suitable for more miniaturized scenarios.

[0083] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A surface acoustic wave device, characterized by, The application relates to an acoustic surface wave device. The acoustic surface wave device comprises a substrate (100), a solder pad (11), an interdigital transducer (300), a heat-conducting metal structure (400) and a heat-dissipating metal layer (12). The substrate (100) has opposite first and second surfaces (110, 120) along the thickness direction (A) of the substrate. The solder pad (11) and the interdigital transducer (300) are arranged on the first surface (110) and connected by a metal wiring structure (13). The heat-dissipating metal layer (12) is arranged on the second surface (120), one end of the heat-conducting metal structure (400) is arranged on the first surface (110), and the other end is connected with the heat-dissipating metal layer (12). The heat-conducting metal structure (400) comprises a horizontal segment (410) and a vertical segment (420). The horizontal segment (410) is arranged on the first surface (110). One end of the vertical segment (420) is connected with the end of the horizontal segment (410), and the other end of the vertical segment (420) extends to the heat-dissipating metal layer (12) along the thickness direction (A) of the substrate.

2. The acoustic surface wave device according to claim 1, wherein: A through hole (101) is arranged on the substrate (100) along the thickness direction (A) of the substrate, and the vertical segment (420) is connected with the heat-dissipating metal layer (12) after penetrating through the through hole (101).

3. The acoustic surface wave device according to claim 2, wherein: The heat-conducting metal structure (400) is arranged in the through hole (101) in the form of a metal plating film.

4. The acoustic surface wave device according to claim 2, wherein: The through hole (101) penetrates through from the first surface (110) to the second surface (120). The caliber of the through hole (101) is 5-50 microns along the length direction (B) of the substrate. The caliber of the through hole (101) is 3-30 microns along the width direction (C) of the substrate.

5. The acoustic surface wave device according to claim 1, wherein: The horizontal segment (410) is arranged at a preset position on the first surface (110), and the preset position is configured as the region with the highest temperature on the first surface (110) when the acoustic surface wave device works.

6. The acoustic surface wave device according to claim 1, wherein: The horizontal segment (410) has a transverse dimension of 5-50 microns.

7. The acoustic surface wave device according to claim 1, wherein: The heat-dissipating metal layer (12) has a thickness of 0.5-5 microns.

8. The acoustic surface wave device according to claim 1, wherein: Further comprising a plurality of bumps (14), each of which is arranged on the first surface (110); the pad (11) is arranged on the first surface (110) through the bump (14).

9. The SAW device according to claim 8, characterized in that: Further comprising a packaging substrate (15) and a plastic package structure (16); The packaging substrate (15) is located on the side opposite to the first surface (110) of the substrate (100), and the packaging substrate (15) is spaced apart from the first surface (110) of the substrate (100); Along the peripheral direction of the substrate (100), the plastic package structure (16) is enclosed in the periphery of the substrate (100); along the thickness direction (A) of the substrate, one side of the plastic package structure (16) is bonded to one side of the packaging substrate (15); the first surface (110) of the substrate (100), the top surface of the packaging substrate (15) and the inner wall of the plastic package structure (16) together enclose a sealed containing cavity (500); the pad (11), the interdigital transducer (300) and the heat-conducting metal structure (400) of the first surface (110) are located in the containing cavity (500).

10. The SAW device according to claim 1, characterized in that: The heat-conducting metal structure (400) each comprises a bottom layer and a surface layer connected to each other; the material of the bottom layer is titanium, and the material of the surface layer is copper, aluminum copper alloy or aluminum.

11. The SAW device of claim 1, wherein: The interdigital transducer is composed of two groups of interdigital electrodes (310) staggered distributed; the constituent material of the interdigital electrode (310) includes aluminum or aluminum copper alloy.

12. A preparation method of a SAW device, characterized in that: The preparation method is used for preparing the SAW device according to any one of claims 1-10; the preparation method comprises: Arranging the heat-conducting metal structure (400) extending from the first surface (110) to the second surface (120) on the substrate (100); Arranging the heat-dissipating metal layer (12) on the second surface (120), and connecting the heat-conducting metal structure (400) with the heat-dissipating metal layer (12).

13. The preparation method of the SAW device according to claim 12, characterized in that: A through hole (101) is opened on the substrate (100), the through hole (101) extends from the first surface (110) to the second surface (120); a vertical section (420) of the heat-conducting metal structure (400) is formed by metal plating film in the through hole (101).

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