Surface acoustic wave device and preparation method thereof

Abstract

The invention relates to the technical field of semiconductors, in particular to a surface acoustic wave device and a preparation method thereof. The surface acoustic wave device comprises a substrate, a bonding pad, an interdigital transducer, a heat conduction metal structure and a heat dissipation metal layer. The substrate is provided with a first surface and a second surface which are opposite to each other along the thickness direction of the substrate; the bonding pad and the interdigital transducer are arranged on the first surface; the bonding pad is connected with the interdigital transducer through a metal wiring structure; the interdigital transducers are connected through a metal wiring structure; the heat dissipation 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; and the heat conduction metal structure is not in contact with the interdigital transducer. Therefore, the heat conduction metal belongs to heat dissipation metal connection, heat of the surface area of the chip is led to the back surface of the chip, the heat dissipation area is increased, and the heat dissipation capability of the product is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a surface acoustic wave device and a preparation method thereof. Background Art

[0002] SAW filters, due to their excellent performance, meet the requirements of modern communication system equipment and portable phones for miniaturization, high performance, and high reliability. They are also flexible in design and can be well applied to medium and low frequency bands, so they have broad market prospects. As product sizes develop towards thinner and smaller shapes, higher requirements are placed on product design, especially when device sizes are reduced and circuit design is centralized. When the product is working, the local heat on the surface will be relatively high (the main working circuit of the SAW filter is concentrated on the wafer surface). If the heat cannot be dissipated in time, the device will face the risk of electrode burning and product failure. Summary of the invention

[0003] The purpose of the present invention includes, for example, providing a surface acoustic wave device and a preparation method thereof, which can connect the heat-conducting metal to the heat-dissipating metal to guide the heat of the chip surface area to the back of the chip, increase the heat dissipation area, and enhance the heat dissipation capacity 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, pad, interdigital transducer, thermal conductive metal structure and heat dissipation metal layer;

[0007] Along the thickness direction of the substrate, the substrate has a first surface and a second surface opposite to each other;

[0008] The pad and the IDT are both disposed on the first surface; the pad and the IDT are connected via a metal wiring structure; and the IDTs are connected via a metal wiring structure.

[0009] The heat dissipation metal layer is arranged on the second surface; one end of the heat conductive metal structure is arranged on the first surface, and the other end is connected to the heat dissipation metal layer; the heat conductive metal structure is not in contact with the interdigital transducer.

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

[0011] The horizontal section 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 to the heat dissipation metal layer along the thickness direction of the substrate.

[0013] In an optional embodiment, a through hole is opened on the substrate along the thickness direction of the substrate; and the vertical section is connected to the heat dissipation metal layer after passing through the through hole.

[0014] In an optional embodiment, the heat-conducting metal structure is disposed in the through hole by means of metal plating.

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

[0016] Along the length direction of the substrate, the diameter of the through hole is 5 microns to 50 microns;

[0017] Along the width direction of the substrate, the diameter of the through hole is 3 micrometers to 30 micrometers.

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

[0019] In an optional embodiment, the horizontal segment has a lateral dimension of 5 microns to 50 microns.

[0020] In an optional embodiment, the heat dissipation metal layer has a thickness of 0.5 micrometers to 5 micrometers.

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

[0022] In an optional implementation, it further includes a plurality of bumps, and the bumps are all disposed on the first surface; the pad is disposed on the first surface through the bumps.

[0023] In an optional embodiment, it also includes a packaging substrate and a plastic packaging structure;

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

[0025] Along the peripheral direction of the substrate, the plastic encapsulation structure is enclosed by the peripheral edge of the substrate; along the thickness direction of the substrate, one side of the plastic encapsulation structure is bonded to one side of the packaging substrate; the first surface of the substrate, the top surface of the packaging substrate and the inner wall of the plastic encapsulation structure are jointly enclosed to form a sealed accommodating cavity; the solder pad, the interdigital transducer and the thermally conductive metal structure of the first surface are located in the accommodating cavity.

[0026] In an optional embodiment, the heat-conducting metal structure includes a bottom layer and a surface layer that are 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.

[0027] In an optional embodiment, the interdigital transducer is composed of two groups of interdigital electrodes that are staggered; the constituent material of the interdigital electrodes includes aluminum or aluminum-copper alloy.

[0028] In a second aspect, the present invention provides a preparation method, which is used to prepare a surface acoustic wave device as described in any one of the aforementioned embodiments; the preparation method comprises:

[0029] Disposing the heat-conducting metal structure extending from the first surface to the second surface on the substrate;

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

[0031] In an optional embodiment, a through hole is opened on the substrate, and the through hole extends from the first surface to the second surface; and a metal coating is performed in the through hole to form a vertical section of the heat-conducting metal structure.

[0032] In an optional implementation, the heat dissipation metal layer is disposed on the second surface by a sputtering process.

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

[0034] The surface acoustic wave device of this scheme includes a substrate, a pad, an interdigital transducer, a heat-conducting metal structure and a heat-dissipating metal layer. The pad and the interdigital transducer are arranged on the first surface of the substrate, that is, the first surface is the main working area of ​​the components, and therefore is also the area where the chip generates the most heat. One end of the heat-conducting metal structure is arranged on the first surface, and the other end extends to the second surface and is connected to the heat-dissipating metal layer, so that the heat generated by the first surface can be timely and efficiently conducted to the heat-dissipating metal layer, which is conducive to timely heat dissipation. Further, because there is only a heat-dissipating metal layer on the second surface and no other structure occupies it, the larger surface area has a better heat dissipation effect, which is conducive to timely exporting the internal heat of the product and improving the product's withstand power. Compared with the prior art, the device size is reduced and the circuit design is centralized. When the product is working, the local surface heat will be relatively high, and it cannot be dissipated in time. The device will face the situation of electrode burning and causing product function failure. This scheme can have the advantages of integration and miniaturization, and can also improve the heat dissipation capacity and ensure the stability and reliability of the device operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

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

[0037] Figure 2 A schematic structural diagram of a surface acoustic wave device from another perspective of an embodiment of the present invention;

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

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

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

[0041] Figure 6 It is a schematic diagram of process 4 of the method for preparing a 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-package substrate; 16-plastic package structure; 100-substrate; 101-through hole; 110-first surface; 120-second surface; 300-interdigital transducer; 310-interdigital electrode; 400-thermal conductive metal structure; 410-horizontal section; 420-vertical section; 500-accommodating cavity; A-thickness direction of substrate; B-length direction of substrate; C-width direction of substrate. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0048] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may 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 pad 11 and the IDT 300 are both disposed on the first surface 110; the pad 11 and the IDT 300 are connected via a metal wiring structure 13; and the IDTs 300 are connected via the metal wiring structure 13;

[0052] The heat dissipation metal layer 12 is disposed on the second surface 120 . One end of the heat conductive 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 conductive metal structure 400 does not contact the IDT 300 .

[0053] The surface acoustic wave device of this scheme includes a substrate 100, a pad 11, an interdigital transducer 300, a heat-conducting metal structure 400 and a heat-dissipating metal layer 12. The pad 11 and the interdigital transducer 300 are both arranged on the first surface 110 of the substrate 100, that is, the first surface 110 is the main working area of ​​the components, and therefore is also the area where the chip working heat accumulates the most. One end of the heat-conducting metal structure 400 is arranged on the first surface 110, and the other end extends to the second surface 120 and is connected to the heat-dissipating metal layer 12, so that the heat generated by the first surface 110 can be timely and efficiently conducted to the heat-dissipating metal layer 12, which is conducive to timely heat dissipation. Furthermore, because the second surface 120 only has the heat-dissipating metal layer 12 and is not occupied by other structures, the larger surface area has a better heat dissipation effect, which is conducive to timely exporting the internal heat of the product and improving the product's withstand power. Compared with the prior art, the device size is reduced and the circuit design is centralized. When the product is working, the local surface heat will be relatively high and cannot be dissipated in time. The device will face the situation of electrode burning and product failure. This solution can have the advantages of integration and miniaturization, and can also improve the heat dissipation capacity to ensure the stability and reliability of the device operation.

[0054] It should be noted that the interdigital transducer 300 (IDT) has two sets of interdigital electrodes 310 arranged in an interlaced manner, and its function is to realize acoustic-electrical transduction. The IDT is the most basic unit of the surface acoustic wave device. The substrate 100 is a piezoelectric substrate 100. The heat-conducting metal structure 400 is used to conduct the heat on the chip to the heat dissipation metal layer 12.

[0055] In an optional embodiment, the interdigital transducer 300 is composed of two groups of interdigital electrodes 310 that are staggered; the constituent material of the interdigital electrodes 310 includes aluminum or aluminum-copper alloy. That is, the material of the interdigital electrodes 310 can be aluminum or aluminum-copper alloy. In this way, the working performance of the interdigital transducer 300 can be guaranteed.

[0056] In an optional embodiment, the heat-conducting metal structure 400 includes a bottom layer and a surface layer connected to each other; the bottom layer is made of titanium, and the surface layer is made of copper, aluminum-copper alloy or aluminum. Such a structure not only ensures that the heat-conducting metal structure 400 has outstanding structural performance, but also has good thermal conductivity, so that the temperature of the working area of ​​the first surface 110 can be timely conducted and heat dissipated.

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

[0058] As can be seen from the figure, the surface acoustic wave device further includes a plurality of bumps 14 , and the bumps 14 are all 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 may be a gold ball or a solder ball, which is 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 further includes a packaging substrate 15 and a plastic packaging structure 16; the packaging substrate 15 is located on a side facing the first surface 110 of the substrate 100, and a distance is maintained between the packaging substrate 15 and the first surface 110 of the substrate 100;

[0061] Along the peripheral direction of the substrate 100, the plastic encapsulation structure 16 is enclosed at the periphery of the substrate 100; along the thickness direction A of the substrate, one side of the plastic encapsulation structure 16 is bonded to one side of the encapsulation substrate 15; the first surface 110 of the substrate 100, the top surface of the encapsulation substrate 15 and the inner wall of the plastic encapsulation structure 16 are jointly enclosed to form a sealed accommodating 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 accommodating cavity 500.

[0062] The packaging substrate 15 is used to carry the chip to ensure the structural stability and reliability of the entire device. The plastic packaging structure 16 can support the heat dissipation metal layer 12 and the packaging substrate 15 on the one hand, and provide sealing for the entire device on the other hand, 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 heat-conducting metal structure 400 includes 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 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] Such a heat-conducting metal structure 400 can reduce the space occupied in the device and has a better heat-conducting effect while avoiding interference with other components. Optionally, the horizontal section 410 and the vertical section 420 are perpendicular to each other. This is conducive to further reducing the path length of the heat-conducting metal structure 400.

[0065] Furthermore, in an optional embodiment, a through hole 101 is provided on the substrate 100 along the thickness direction A of the substrate; the vertical section 420 penetrates the through hole 101 and is connected to the heat dissipation metal layer 12. In this way, the chip can 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 making the surface acoustic wave device have excellent heat dissipation performance.

[0066] In an optional embodiment, the heat-conducting metal structure 400 is disposed in the through hole 101 by metal plating. Optionally, the through hole 101 is formed through the device by laser drilling, and then the back of the wafer is protected by film and heat-conducting metal is plated in the front punching area and the reserved area on the surface of the pad 11, thereby forming the heat-conducting 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 diameter of the through hole 101 is 5 micrometers to 50 micrometers; along the width direction C of the substrate, the diameter of the through hole 101 is 3 micrometers to 30 micrometers. Optionally, the shape of the through hole 101 can be circular, square, etc., which is not limited here.

[0068] It should be noted that, in an optional embodiment, the horizontal section 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 working.

[0069] Further, 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 produces a piezoelectric effect; the pad 11 is connected to the metal wiring; the pad 11 is connected to the interdigital transducer 300 through the metal wiring; the sound-to-electric conversion is achieved through the interdigital transducer 300; the thermal conductive metal structure 400 conducts the heat on the chip; the bump 14 leads out the circuit and is connected to the packaging substrate 15; the plastic packaging structure 16 wraps the chip to protect it from interference from the external environment; the heat dissipation metal layer 12 dissipates heat and cools it down; the packaging substrate 15 carries the chip, and by connecting the thermal conductive metal to the heat dissipation metal layer 12, the heat from the surface area of ​​the chip is led to the back of the chip, thereby increasing the heat dissipation area, which on the one hand enhances the heat dissipation capacity of the chip product, and on the other hand can effectively reduce the size of the product.

[0071] In a second aspect, the present invention provides a preparation method, which is used to prepare the surface acoustic wave device of any one of the aforementioned embodiments; the preparation method comprises:

[0072] A heat-conducting metal structure 400 extending from the first surface 110 to the second surface 120 is disposed on the substrate 100;

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

[0074] In an optional embodiment, a through hole 101 is opened on the substrate 100, and the through hole 101 extends from the first surface 110 to the second surface 120; a metal film is plated in the through hole 101 to form a vertical section 420 of the heat-conducting metal structure 400. Optionally, the heat dissipation metal layer 12 is disposed on the second surface 120 by a sputtering process.

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

[0076] Process 1: Figure 3 As shown, firstly, the surface of the substrate 100 is coated with glue, exposed and developed, and the position where the IDT 300 is not needed is protected with photoresist, and then the IDT 300 is formed by processes such as coating, exposure, development and coating (see process 1 for details). The constituent material of the interdigital electrodes 310 in the IDT 300 includes pure aluminum or aluminum-copper alloy. Repeat this process to form a frequency modulation protective layer on the IDT 300.

[0077] Process 2: Figure 4 As shown, after process 1, the first surface 110 of the substrate 100 is coated with a resin, exposed and developed, and the pad 11 is formed by photolithography, development and coating. The material of the pad 11 includes aluminum, aluminum copper or gold.

[0078] Process 3: Figure 5 As shown, after process 2, the first surface 110 of the substrate 100 is coated with glue, exposed and developed, and the laser-punched hole 101 area and the thermal conductive metal structure 400 area are reserved through photolithography and development. Then, a through hole 101 is preset on the substrate 100 by laser drilling, and then a film is attached to the back of the wafer for protection. The thermal conductive metal structure 400 (the bottom material of the thermal conductive metal structure 400 is Ti and the surface material is Cu) is plated in the through hole 101 area of ​​the first surface 110 and the reserved area on the surface of the pad 11.

[0079] Process 4: Figure 6As shown, after process 3, a ball is planted at the window position of the pad 11 (i.e., a bump 14 is set), and then the normal CSP (Chip Scale Package) process is used to complete the processes of wafer cutting, flip-chip welding, plastic sealing, baking, etc. After baking, the plastic cover of the entire substrate is thinned to expose the second surface 120 of the piezoelectric substrate 100, and a heat dissipation metal layer 12 is formed on the second surface 120 through a sputtering process to finally form a complete heat dissipation path, ensuring that the heat from 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 a method for manufacturing the same, which have at least the following advantages:

[0081] 1. By improving the heat dissipation capacity of the product, the power tolerance of the product is improved, thereby improving the product reliability.

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

[0083] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A surface acoustic wave device, characterized in that: include: A substrate (100), a pad (11), an interdigital transducer (300), a heat-conducting metal structure (400) and a heat-dissipating metal layer (12); 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; The solder pad (11) and the interdigital transducer (300) are both arranged on the first surface (110); the solder pad (11) and the interdigital transducer (300) are connected via a metal wiring structure (13); and the interdigital transducers (300) are connected via the metal wiring structure (13); The heat dissipation metal layer (12) is arranged on the second surface (120); one end of the heat conductive metal structure (400) is arranged on the first surface (110), and the other end is connected to the heat dissipation metal layer (12); the heat conductive metal structure (400) is not in contact with the interdigital transducer (300).

2. The surface acoustic wave device according to claim 1, characterized in that: The heat-conducting metal structure (400) comprises a horizontal section (410) and a vertical section (420); The horizontal section (410) is disposed on the first surface (110); One end of the vertical section (420) is connected to the end of the horizontal section (410), and the other end of the vertical section (420) extends to the heat dissipation metal layer (12) along the thickness direction (A) of the substrate.

3. The surface acoustic wave device according to claim 2, characterized in that: A through hole (101) is provided on the substrate (100) along the thickness direction (A) of the substrate; and the vertical section (420) penetrates the through hole (101) and is connected to the heat dissipation metal layer (12).

4. The surface acoustic wave device according to claim 3, characterized in that: The heat-conducting metal structure (400) is arranged in the through hole (101) by means of metal plating.

5. The surface acoustic wave device according to claim 3, characterized in that: The through hole (101) penetrates from the first surface (110) to the second surface (120); Along the length direction (B) of the substrate, the diameter of the through hole (101) is 5 micrometers to 50 micrometers; Along the width direction (C) of the substrate, the diameter of the through hole (101) is 3 micrometers to 30 micrometers.

6. The surface acoustic wave device according to claim 2, characterized in that: The horizontal section (410) is arranged 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 working.

7. The surface acoustic wave device according to claim 2, characterized in that: The horizontal segment (410) has a lateral dimension of 5 micrometers to 50 micrometers.

8. The surface acoustic wave device according to claim 1, characterized in that: The thickness of the heat dissipation metal layer (12) is 0.5 micrometers to 5 micrometers.

9. The surface acoustic wave device according to claim 1, characterized in that: It also comprises a plurality of bumps (14), wherein the bumps (14) are all arranged on the first surface (110); and the pad (11) is arranged on the first surface (110) via the bumps (14).

10. The surface acoustic wave device according to claim 9, characterized in that: It also includes a packaging substrate (15) and a plastic packaging structure (16); The packaging substrate (15) is located on a side facing the first surface (110) of the substrate (100), and a distance is maintained between the packaging substrate (15) and the first surface (110) of the substrate (100); Along the peripheral direction of the substrate (100), the plastic encapsulation structure (16) is enclosed at the peripheral edge of the substrate (100); along the thickness direction (A) of the substrate, one side of the plastic encapsulation structure (16) is bonded to one side of the encapsulation substrate (15); the first surface (110) of the substrate (100), the top surface of the encapsulation substrate (15) and the inner wall of the plastic encapsulation structure (16) are jointly enclosed to form a sealed accommodating cavity (500); the solder pad (11), the interdigital transducer (300) and the heat-conducting metal structure (400) of the first surface (110) are located in the accommodating cavity (500).

11. The surface acoustic wave device according to claim 1, characterized in that: The heat-conducting metal structures (400) each comprise a bottom layer and a surface layer which are connected to each other; the bottom layer is made of titanium, and the surface layer is made of copper, aluminum-copper alloy or aluminum.

12. The surface acoustic wave device according to claim 1, characterized in that: The interdigital transducer is composed of two groups of interdigital electrodes (310) that are distributed in an interlaced manner; the constituent material of the interdigital electrodes (310) includes aluminum or an aluminum-copper alloy.

13. A method for preparing a surface acoustic wave device, characterized in that: The preparation method is used to prepare the surface acoustic wave device according to any one of claims 1 to 11; the preparation method comprises: The heat-conducting metal structure (400) extending from the first surface (110) to the second surface (120) is provided on the substrate (100); The heat dissipation metal layer (12) is arranged on the second surface (120), and the heat-conducting metal structure (400) is connected to the heat dissipation metal layer (12).

14. The method for preparing a surface acoustic wave device according to claim 13, characterized in that: A through hole (101) is opened on the substrate (100), and the through hole (101) extends from the first surface (110) to the second surface (120); a metal coating is performed in the through hole (101) to form a vertical section (420) of the heat-conducting metal structure (400).

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