Elastic wave device and method for manufacturing same

Abstract

The embodiment of the invention provides a manufacturing method of an elastic wave device and the elastic wave device. The manufacturing method of the elastic wave device comprises the following steps: a chip manufacturing process: forming at least one resonator and at least one bonding pad on a piezoelectric substrate; a half-cutting step of performing half-cutting on the piezoelectric substrate along a cutting line to form a groove in the piezoelectric substrate; a packaging process: a wall layer, a cover layer and a metal bump are sequentially formed on the piezoelectric substrate, at least one part of the wall layer and at least one part of the cover layer are in contact with the side wall of the groove, a sealed cavity is formed in the corresponding position of the resonator, and the metal bump is arranged on the cover layer and electrically connected with the bonding pad through a through hole; and a separation step of separating the piezoelectric substrate along the grooves to form a plurality of elastic wave devices. According to the elastic wave device manufacturing method provided by the embodiment of the invention, the sealing performance of the elastic wave device can be further improved, so that the moisture-proof performance of the elastic wave device is improved.

Description

Elastic wave devices and their manufacturing methods Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for manufacturing an elastic wave device and an elastic wave device. Background Technology

[0002] Elastic wave devices, characterized by low cost, small size, and multiple functions, have found widespread application in radar, communication, and navigation fields. The most commonly used elastic wave devices in mobile phone and base station communications include elastic wave resonators, elastic wave filters composed of multiple elastic wave resonators, and elastic wave duplexers and multiplexers composed of multiple elastic wave filters. Existing elastic wave devices typically have resonators and pads mounted on a piezoelectric substrate, with wall layers and capping layers on the upper surface of the substrate, forming a sealed space for the resonator. However, the sealing performance of existing elastic wave devices is not yet ideal, posing a risk of moisture ingress during use and affecting their lifespan.

[0003] Therefore, there is an urgent need to provide a manufacturing method for elastic wave devices and an elastic wave device in order to improve the moisture-proof performance of elastic wave devices. Summary of the Invention

[0004] Therefore, in order to overcome at least some of the defects and deficiencies in the prior art, embodiments of the present invention provide a method for manufacturing an elastic wave device and an elastic wave device.

[0005] Specifically, in one aspect, an embodiment of the present invention provides a method for manufacturing an elastic wave device, comprising: a chip fabrication step, forming at least one resonator and at least one pad on a piezoelectric substrate; a half-cutting step, half-cutting the piezoelectric substrate along a cutting line to form a groove on the piezoelectric substrate; an encapsulation step, sequentially forming a wall layer, a capping layer, and a metal bump on the piezoelectric substrate, wherein at least a portion of the wall layer and the capping layer contact the sidewall of the groove and form a sealed cavity at the corresponding position of the resonator, and the metal bump is disposed on the capping layer and electrically connected to the pad through a through hole; and a separation step, separating the piezoelectric substrate along the groove to form a plurality of elastic wave devices.

[0006] In one specific embodiment of the present invention, the packaging process includes: a first sub-process, forming a wall layer on the piezoelectric substrate, wherein the edge of the wall layer extends beyond the edge of the groove, and baking the wall layer so that the edge of the wall layer contacts the sidewall of the groove.

[0007] In one specific embodiment of the present invention, the encapsulation process further includes: a second sub-process, forming the cover layer on the wall layer, wherein the edge of the cover layer extends beyond the edge of the groove, and baking the cover layer so that the edge of the cover layer contacts the sidewall of the groove.

[0008] In one specific embodiment of the present invention, at least one of the resonators is at a distance of less than or equal to 50 μm from the sidewall of the groove.

[0009] In one specific embodiment of the present invention, the distance from the lower edge of the through hole to the sidewall of the groove is less than 100 μm.

[0010] In one specific embodiment of the present invention, during the encapsulation process, the wall layer contacts the sidewall of the groove, and the capping layer covers the sidewall of the wall layer.

[0011] On the other hand, embodiments of the present invention also provide an elastic wave device, comprising: an elastic wave chip including a piezoelectric substrate, at least one resonator, metal wiring, and at least one pad, wherein the piezoelectric substrate has opposing first and second surfaces, and sidewalls connecting the first and second surfaces, the resonator, the metal wiring, and the pads are located on the first surface of the piezoelectric substrate, and the distance from the resonator to the sidewall of the piezoelectric substrate is less than or equal to 50 μm; a capping layer formed on the first surface of the piezoelectric substrate and contacting the sidewall of the piezoelectric substrate, and the capping layer and the piezoelectric substrate forming a sealed cavity above the resonator; and a metal bump formed on the capping layer and connected to the pads through a through hole.

[0012] In one specific embodiment of the present invention, the elastic wave device further includes: a wall layer formed between the first surface of the piezoelectric substrate and the capping layer, and in contact with the sidewall of the piezoelectric substrate; the capping layer, the wall layer, and the piezoelectric substrate form a sealed cavity above the resonator; and the metal bump penetrates the capping layer and the wall layer and is connected to the pad.

[0013] In one specific embodiment of the present invention, the distance from the lower edge of the through hole to the sidewall of the piezoelectric substrate is less than 100 μm.

[0014] In one specific embodiment of the present invention, the edge of the cover layer has rounded corners.

[0015] In one specific embodiment of the present invention, the capping layer covers the sidewall of the wall layer and contacts the sidewall of the piezoelectric substrate.

[0016] In one specific embodiment of the present invention, the wall layer and / or the capping layer are selected from photosensitive materials.

[0017] In one specific embodiment of the present invention, the capping layer or the wall layer covers the metal wiring exposed on one side of the first surface of the piezoelectric substrate.

[0018] As can be seen from the above, the embodiments of the present invention manufacture elastic wave devices through chip fabrication, half-cutting, packaging, and separation processes. By sequentially forming a wall layer, a capping layer, and metal bumps on the piezoelectric substrate, and at least a portion of the wall layer and the capping layer contacting the sidewall of the groove, a sealed cavity is formed at the corresponding position of the resonator. Since at least a portion of the wall layer and the capping layer contact the sidewall of the groove, the sealing performance can be further improved, and the moisture resistance of the elastic wave device can also be improved. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a schematic flowchart of a method for manufacturing an elastic wave device according to an embodiment of the present invention.

[0021] Figure 2 is a schematic diagram of the structure of an elastic wave device provided in an embodiment of the present invention.

[0022] Figure 3A is a top view of the elastic wave device in Figure 2.

[0023] Figure 3B is a partial structural schematic diagram of the elastic wave device in Figure 3A.

[0024] Figure 3C is a schematic diagram of the resonator, pads, metal wiring, and through-hole in the elastic wave device of Figure 3A.

[0025] Figures 4A to 4F are schematic diagrams of the process structure of the manufacturing method of the elastic wave device provided in the embodiments of the present invention.

[0026] Figures 5A to 5D are schematic diagrams of the process structure for manufacturing the wall layer of elastic wave devices.

[0027] Figures 6A to 6D are schematic diagrams of another process structure for manufacturing the wall layer of elastic wave devices.

[0028] Figures 7A to 7F are schematic diagrams of the process structure for manufacturing the capping layer of elastic wave devices.

[0029] Main component designations

[0030] 10. Elastic wave device; 11. Sealed cavity; 12. Through hole; 13. Cutting line; 100. Piezoelectric substrate; 110. First surface; 120. Second surface; 130. Sidewall; 200. Resonator; 310. Pad; 320. Metal wiring; 330. UBM; 400. Wall layer; 500. Cap layer; 600. Metal bump; 700. Support tape. Detailed Implementation

[0031] 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. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0032] It should be noted that all directional indications (such as up, down, left, right, front, back, top, bottom) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. In the embodiments of the present invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0033] Referring to Figures 1 and 2, this embodiment of the invention provides a method for manufacturing an elastic wave device and an elastic wave device 10.

[0034] Specifically, the manufacturing method of an elastic wave device may include, for example, the following steps:

[0035] S10, chip fabrication process, forming at least one resonator and at least one pad on a piezoelectric substrate;

[0036] S20, a half-cutting process, in which the piezoelectric substrate is half-cut along the cutting line to form a groove on the piezoelectric substrate;

[0037] S30, Packaging process, a wall layer, a cap layer and a metal bump are formed sequentially on the piezoelectric substrate. At least a portion of the wall layer and the cap layer are in contact with the sidewall of the groove and form a sealed cavity at the corresponding position of the resonator. The metal bump is disposed on the cap layer and electrically connected to the pad through a through hole.

[0038] S40, Separation process, the piezoelectric substrate is separated along the groove to form multiple elastic wave devices.

[0039] Referring to Figures 2 and 3A to 3C, the elastic wave device 10 provided in this embodiment can be manufactured, for example, by the elastic wave device manufacturing method described above. Specifically, the elastic wave device 10 may include, for example, an elastic wave chip, a capping layer 500, and metal bumps 600. The elastic wave chip includes a piezoelectric substrate 100, at least one resonator 200, at least one pad 310, and metal wiring 320. The piezoelectric substrate 100 may, for example, have a first surface 110 and a second surface 120 disposed opposite to each other, and a sidewall 130 connecting the first surface 110 and the second surface 120. The first surface 110 may, for example, be an upper surface, and the second surface 120 may, for example, be a lower surface.

[0040] A resonator 200, metal wiring 320, and pads 310 are located on a first surface 110 of a piezoelectric substrate 100. The resonator 200 may include, for example, an interdigital transducer (IDT) and reflectors disposed at both ends of the IDT. A capping layer 500 is formed on the first surface 110 of the piezoelectric substrate 100 and contacts the sidewall 130 of the piezoelectric substrate 100. The capping layer 500 and the piezoelectric substrate 100 form a sealed cavity 11 above the resonator 200, sealing the resonator 200. Metal bumps 600 are formed on the capping layer 500 and penetrate the capping layer 500 through through-holes 12 to connect to the pads 310.

[0041] The elastic wave device 10 provided in this embodiment is provided with an elastic wave chip, a capping layer 500 and metal bumps 600. The elastic wave chip includes a piezoelectric substrate 100 and a resonator 200, metal wiring 320 and pads 310 disposed on the piezoelectric substrate 100. The capping layer 500 is disposed on the piezoelectric substrate 100 and contacts the sidewall 130 of the piezoelectric substrate 100. By setting the capping layer 500 to contact the sidewall 130 of the piezoelectric substrate 100, the capping layer 500 can cover the sidewall 130 of the piezoelectric substrate 100 along the first surface 110 of the piezoelectric substrate 100, which can further improve the sealing performance and the moisture-proof performance of the elastic wave device 10.

[0042] Referring to Figures 3B and 3C, in this embodiment, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 is less than or equal to 50 μm. The distance D2 can be, for example, 20 μm, 30 μm, 35 μm, 40 μm, or 50 μm. Preferably, the distance D2 can be, for example, greater than or equal to 10 μm and less than or equal to 30 μm. Here, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 mainly refers to the distance from the edge of the resonator 200 extending perpendicularly to the IDT electrode to the sidewall 130 of the piezoelectric substrate 100. With the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 less than or equal to 50 μm, the size of the elastic wave device 10 can be reduced, further miniaturizing the elastic wave device 10. Furthermore, by setting the distance D2 between the resonator 200 and the sidewall 130 of the piezoelectric substrate 100 to be less than or equal to 50 μm, and by setting the cover layer 500 to contact the sidewall 130 of the piezoelectric substrate 100, the cover layer 500 can cover the sidewall 130 of the piezoelectric substrate 100 along the first surface 110 of the piezoelectric substrate 100. This avoids the problem of reduced sealing caused by the resonator 200 being too close to the sidewall of the piezoelectric substrate 100, further improving the sealing performance and enhancing the moisture resistance of the elastic wave device 10. This allows the elastic wave device 10 to be miniaturized while maintaining good reliability.

[0043] The elastic wave device 10 may, for example, further include a wall layer 400 formed between the first surface 110 of the piezoelectric substrate 100 and the capping layer 500. The wall layer 400 may also, for example, contact the sidewall 130 of the piezoelectric substrate 100. The capping layer 500, the wall layer 400, and the piezoelectric substrate 100 form a sealed cavity 11 (hollow portion) above the resonator 200. The wall layer 400 may, for example, form a cavity enclosing the piezoelectric substrate 100, and the capping layer 500 covers the wall layer 400, thereby forming the sealed cavity 11. In this embodiment, the capping layer 500 may, for example, cover the sidewall of the wall layer 400 and contact the sidewall 130 of the piezoelectric substrate 100. By having both the wall layer 400 and the capping layer 500 contact the sidewall 130 of the piezoelectric substrate 100, the sealing performance can be further improved, and the moisture-proof performance of the elastic wave device 10 can also be improved.

[0044] In one embodiment of this example, referring again to Figures 3B and 3C, the distance from the lower edge of the through-hole 12 to the sidewall 130 of the piezoelectric substrate 100 is less than 100 μm. Specifically, the distance D1 from the pad 310 to the sidewall 130 of the piezoelectric substrate 100 can be, for example, 35 μm, 50 μm, 60 μm, 70 μm, or 100 μm. Preferably, the distance from the lower edge of the through-hole 12 to the sidewall 130 of the piezoelectric substrate 100 is greater than or equal to 10 μm and less than or equal to 35 μm. With this arrangement, the size of the elastic wave device 10 can be reduced, further miniaturizing the elastic wave device 10.

[0045] In this embodiment, the piezoelectric substrate 100 is used to support the piezoelectric material and provide electrical connection. The piezoelectric substrate 100 is typically made of a material with piezoelectric properties, such as lithium tantalate (LiTaO3), lithium niobate (LiNbO3), or piezoelectric ceramics. In other embodiments, the piezoelectric substrate 100 can be constructed by laminating lithium tantalate or lithium niobate with sapphire, silicon, alumina, spinel, quartz, or glass. In one embodiment of this embodiment, the sidewall 130 of the piezoelectric substrate 100 can be, for example, an inclined surface. The inclined surface is inclined away from the resonator 200 along the direction from the first surface 110 to the second surface 120 of the piezoelectric substrate 100. This can improve the coverage of the wall layer 400 or the capping layer 500 on the piezoelectric substrate 100 and prevent the wall layer 400 or the capping layer 500 covering the sidewall 130 of the piezoelectric substrate 100 from breaking, thereby improving the reliability of the elastic wave device 10. Metal wiring 320 is disposed on the first surface 110 of the piezoelectric substrate 100. The material of the metal wiring 320 can be, for example, TiCu (titanium copper alloy) or NiCu (nickel copper alloy), and the thickness of the metal wiring 320 can be, for example, 1-7 μm. The capping layer 500 or the wall layer 400 can, for example, also cover the metal wiring 320 exposed on one side of the first surface 110 of the piezoelectric substrate 100. The wall layer 400 can, for example, be made of a photosensitive material, specifically, for example, a photosensitive resin. The edges of the wall layer 400 and the edge of the capping layer 500 can also, for example, have rounded corners, which can prevent the wall layer 400 or the capping layer 500 covering the sidewall 130 of the piezoelectric substrate 100 from breaking, thereby improving the reliability of the elastic wave device 10. The material of the capping layer 500 can, for example, be polyimide (PI), epoxy resin, photoresist, silicon, or glass, and can also, for example, be a photosensitive material, specifically, for example, a photosensitive resin.

[0046] To facilitate a clearer understanding of the elastic wave device 10 and the manufacturing method of the elastic wave device provided in this embodiment, the specific process of the manufacturing method of the elastic wave device will be described in detail below.

[0047] Referring to Figure 4A, in the chip fabrication process, at least one resonator 200 and at least one pad 310 are formed on a piezoelectric substrate 100. The piezoelectric substrate 100 may include, for example, a support layer and a piezoelectric layer. The support layer supports the piezoelectric layer, and its material may be, for example, silicon, glass, sapphire, ceramic, or a mixture primarily composed of silicon, glass, sapphire, and ceramic. The piezoelectric layer may be, for example, lithium carbonate, lithium niobate, etc. Of course, the piezoelectric substrate 100 may also include only a piezoelectric layer; this embodiment is not limited to this. At least one resonator 200 and at least one pad 310 are formed on the piezoelectric substrate 100, thereby forming an elastic surface functional layer on the piezoelectric substrate 100. The number of resonators 200 and pads 310 can be set according to requirements. In this embodiment, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 is less than or equal to 50 μm. Preferably, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 can be, for example, greater than or equal to 10 μm and less than or equal to 30 μm. Here, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 mainly refers to the distance from the edge of the resonator 200 extending perpendicularly to the IDT electrode to the sidewall 130 of the piezoelectric substrate 100. The distance from the lower edge of the through-hole 12 to the sidewall 130 of the piezoelectric substrate 100 is less than 100 μm. Preferably, the distance from the lower edge of the through-hole 12 to the sidewall 130 of the piezoelectric substrate 100 is greater than or equal to 10 μm and less than or equal to 35 μm.

[0048] Referring to Figures 4B and 4C, in the half-cutting process, the piezoelectric substrate 100 is half-cut along the cutting line 13, forming a groove 101 as shown in Figure 4C on the piezoelectric substrate 100. The groove 101 can, for example, form the sidewall of the elastic wave device 10. In one embodiment of this example, the cross-section of the groove 101 can be, for example, an inverted trapezoidal shape. Half-cutting is a technique used in semiconductor manufacturing for wafer dicing. Instead of completely severing the piezoelectric substrate 100, the half-cutting process forms the groove 101 by cutting to a certain depth on the piezoelectric substrate 100. This half-cutting process creates a dicing path (i.e., the groove 101) on the piezoelectric substrate 100, preparing it for subsequent chip separation.

[0049] Referring to Figure 4D, in the encapsulation process, a wall layer 400, a capping layer 500, and a metal bump 600 are sequentially formed on the piezoelectric substrate 100. At least a portion of the wall layer 400 and the capping layer 500 contacts the sidewall of the groove 101 and forms a sealed cavity 11 at the corresponding position of the resonator 200. The metal bump 600 is disposed on the capping layer 500 and is electrically connected to the pad 310 through a through hole 12. In this embodiment, for example, a portion of the wall layer 400 may contact the sidewall of the groove 101, or a portion of the capping layer 500 may contact the sidewall of the groove 101, or both portions of the wall layer 400 and the capping layer 500 may contact the sidewall of the groove 101. The capping layer 500 may, for example, cover the sidewall of the wall layer 400.

[0050] Referring to Figures 4E and 4F, in the separation process, the piezoelectric substrate 100 is separated along the groove 101 to form a plurality of elastic wave devices 10. For example, referring to Figure 4D, a support tape 700 may be applied to the upper surface of the capping layer 500, and then the thickness of the piezoelectric substrate 100 may be gradually reduced by back-side grinding until the chip is separated. Referring to Figure 4E, the support tape 700 is then peeled off, ultimately forming a plurality of elastic wave devices 10.

[0051] Furthermore, the encapsulation process may include, for example, a first sub-process, forming a wall layer 400 on the piezoelectric substrate 100, the edge of the wall layer 400 extending beyond the edge of the groove 101, and baking the wall layer 400 so that the edge of the wall layer 400 contacts the sidewall of the groove 101.

[0052] In one embodiment of this example, specifically referring to FIG. 5A, a dry film is coated on the first surface 110 of the piezoelectric substrate 100. The dry film is a photosensitive material pre-coated on a plastic film and supplied in solid form. The dry film can be attached to the piezoelectric substrate 100, for example, by a lamination process. Referring to FIGS. 5B and 5C, the wall layer 400 can be formed, for example, by photolithography through exposure and development. For example, a pattern on a photomask is transferred to the dry film by ultraviolet exposure using a photolithography machine. The exposed photoresist areas are dissolved using a specific developer, thereby transferring the photolithographic pattern to the dry film. This removes the dry film at the corresponding positions of the groove 101, pad 310, and resonator 200, forming the wall layer 400 as shown in FIG. 5C, with the edge of the wall layer 400 extending beyond the edge of the groove 101. Referring to FIG. 5D, the wall layer 400 is baked so that the edge of the wall layer 400 contacts the sidewall of the groove 101. Through the baking process, the edge of the wall layer 400 can be made to contact the side wall of the groove 101, and the edge of the wall layer 400 is rounded.

[0053] In another embodiment of this invention, specifically referring to FIG. 6A, liquid photoresist is coated on the first surface 110 of the piezoelectric substrate 100. The liquid photoresist is supplied in liquid form and needs to be uniformly coated on the piezoelectric substrate 100 by spin coating, spraying, or other coating methods. The liquid photoresist can be coated, for example, on the first surface 110 of the piezoelectric substrate 100 and on the inner wall and bottom of the groove 101. Referring to FIGS. 6B and 6C, the wall layer 400 can be formed, for example, by exposure and development using a photolithography process. For example, a pattern on a photomask is transferred to the photoresist by ultraviolet exposure using a photolithography machine. The exposed photoresist area is dissolved using a specific developer, thereby transferring the photolithographic pattern to the liquid photoresist. This removes the liquid photoresist at the corresponding positions of the groove 101, the pad 310, and the resonator 200, forming the wall layer 400 as shown in FIG. 6C, and the edge of the wall layer 400 extends beyond the edge of the groove 101. Referring to Figure 6D, the wall layer 400 is baked so that the edge of the wall layer 400 contacts the sidewall of the groove 101. Through the baking process, the edge of the wall layer 400 can be made to contact the sidewall of the groove 101, and the edge of the wall layer 400 forms a rounded corner.

[0054] Furthermore, the encapsulation process may include, for example, a second sub-process: forming the capping layer 500 on the wall layer 400, with the edge of the capping layer 500 extending beyond the edge of the groove 101; and baking the capping layer 500 so that the edge of the capping layer 500 contacts the sidewall of the groove 101. Specifically, referring to FIG7A, the capping layer 500 is first attached to the wall layer 400. The material of the capping layer 500 may be, for example, polyimide (PI), epoxy resin, photoresist, silicon, or glass. Referring to FIG7B, the capping layer 500 may be formed, for example, using a photolithography process through exposure and development. For example, a photolithography machine is used to transfer the pattern on a photomask to photoresist (capping layer 500) through ultraviolet exposure. A specific developer is used to dissolve the exposed photoresist areas, thereby transferring the photolithographic pattern onto the photoresist layer. This removes the photoresist layer at the corresponding positions of the recess 101 and the pad 310, forming the capping layer 500 as shown in FIG7C. The edge of the capping layer 500 extends beyond the edge of the recess 101, and may also extend beyond the sidewall of the wall layer 400, for example. Referring to FIG7D, the capping layer 500 is baked so that the edge of the capping layer 500 contacts the sidewall of the recess 101. Through the baking process, the edge of the capping layer 500 contacts the sidewall of the recess 101, and the edge of the capping layer 500 covers the sidewall of the wall layer 400. Baking also rounds the edges of the capping layer 500.

[0055] Referring to Figure 7E, an under-bump metallization (UBM) 330 is formed on the pad 310. The UBM 330 can be formed, for example, by electroplating. The UBM 330 provides electrical connection between the piezoelectric substrate 100 and the metal bump 600, prevents the formation of intermetallic compounds, enhances mechanical strength, and protects the chip surface. The metal wiring 320 can be formed on the surface of the pad 310, for example, by vapor deposition or sputtering. Referring to Figure 7F, the wall layer 400 and the capping layer 500 form through-holes 12 at corresponding positions on the pad 310. Metal bumps 600 are formed on the UBM, disposed on the surface of the capping layer 500, and electrically connected to the pad 310 through the through-holes.

[0056] In summary, the manufacturing method and elastic wave device 10 provided in this embodiment of the invention include a piezoelectric substrate 100 and a resonator 200, metal wiring 320, and pads 310 disposed on the piezoelectric substrate 100. A capping layer 500 is disposed on the piezoelectric substrate 100 and contacts the sidewall 130 of the piezoelectric substrate 100. By setting the capping layer 500 to contact the sidewall 130 of the piezoelectric substrate 100, the capping layer 500 can cover the sidewall 130 of the piezoelectric substrate 100 along the first surface 110 of the piezoelectric substrate 100, thereby further improving the sealing performance and the moisture-proof performance of the elastic wave device 10. Furthermore, by having a wall layer 400 contact the sidewall 130 of the piezoelectric substrate 100, and the capping layer 500, for example, covering the sidewall of the wall layer 400 and contacting the sidewall 130 of the piezoelectric substrate 100, the sealing performance and the moisture-proof performance of the elastic wave device 10 can be further improved. Furthermore, the distance D2 from the resonator 200 to the sidewall 130 of the piezoelectric substrate 100 is less than or equal to 50 μm. This setting reduces the size of the elastic wave device 10, further miniaturizing it. By setting the distance D1 from the lower edge of the through hole 12 to the sidewall 130 of the piezoelectric substrate 100 to less than 100 μm, the size of the elastic wave device 10 can be further reduced, further miniaturizing it.

[0057] Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention. Provided that the technical features do not conflict, the structure is not contradictory, and the purpose of the invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing an elastic wave device, characterized in that, include: The chip fabrication process involves forming at least one resonator and at least one pad on a piezoelectric substrate; a half-cutting process involves half-cutting the piezoelectric substrate along a cutting line to form a groove on the piezoelectric substrate; a packaging process involves sequentially forming a wall layer, a cap layer, and a metal bump on the piezoelectric substrate, wherein at least a portion of the wall layer and the cap layer contact the sidewall of the groove and form a sealed cavity at the corresponding position of the resonator, and the metal bump is disposed on the cap layer and electrically connected to the pad through a through hole; and a separation process involves separating the piezoelectric substrate along the groove to form multiple elastic wave devices.

2. The method for manufacturing the elastic wave device according to claim 1, characterized in that, The encapsulation process includes: a first sub-process, forming a wall layer on the piezoelectric substrate, wherein the edge of the wall layer extends beyond the edge of the groove, and baking the wall layer so that the edge of the wall layer contacts the sidewall of the groove.

3. The method for manufacturing the elastic wave device according to claim 2, characterized in that, The encapsulation process further includes a second sub-process: forming the cover layer on the wall layer, wherein the edge of the cover layer extends beyond the edge of the groove, and baking the cover layer so that the edge of the cover layer contacts the sidewall of the groove.

4. The method for manufacturing the elastic wave device according to claim 1, characterized in that, At least one of the resonators is at a distance of less than or equal to 50 μm from the sidewall of the groove.

5. The method for manufacturing the elastic wave device according to claim 1, characterized in that, The distance from the lower edge of the through hole to the sidewall of the groove is less than 100 μm.

6. The method for manufacturing an elastic wave device according to claim 1, characterized in that, In the encapsulation process, the wall layer contacts the sidewall of the groove, and the cover layer covers the sidewall of the wall layer.

7. An elastic wave device, characterized in that, include: An elastic wave chip includes a piezoelectric substrate, at least one resonator, metal wiring, and at least one pad, wherein the piezoelectric substrate has opposing first and second surfaces and a sidewall connecting the first and second surfaces, the resonator, the metal wiring, and the pad are located on the first surface of the piezoelectric substrate, and the distance from the resonator to the sidewall of the piezoelectric substrate is less than or equal to 50 μm. A capping layer is formed on the first surface of the piezoelectric substrate and contacts the sidewall of the piezoelectric substrate, and the capping layer and the piezoelectric substrate form a sealed cavity above the resonator; Metal bumps are formed on the capping layer and connected to the pads through a through hole.

8. The elastic wave device according to claim 7, characterized in that, Also includes: A wall layer is formed between the first surface of the piezoelectric substrate and the capping layer, and contacts the sidewall of the piezoelectric substrate. The capping layer, the wall layer, and the piezoelectric substrate form a sealed cavity above the resonator. The metal bump penetrates the capping layer and the wall layer and is connected to the pad.

9. The elastic wave device according to claim 8, characterized in that, The distance from the lower edge of the through hole to the sidewall of the piezoelectric substrate is less than 100 μm.

10. The elastic wave device according to claim 8, characterized in that, The edges of the cover layer have rounded corners.

11. The elastic wave device according to claim 8, characterized in that, The capping layer covers the sidewall of the wall layer and contacts the sidewall of the piezoelectric substrate.

12. The elastic wave device according to claim 8, characterized in that, The wall layer and / or the capping layer are made of photosensitive materials.

13. The elastic wave device according to claim 8, characterized in that, The capping layer or the wall layer covers the metal wiring exposed on one side of the first surface of the piezoelectric substrate.

Images