Elastic wave device and method for manufacturing the same

Abstract

This invention provides a novel structure for a WLP (Whole Lap Paper) elastic wave device that can appropriately improve the heat dissipation of the device chip constituting it. [Solution] The device chip 2 comprises a support layer 3 formed in an area other than the resonator 7 formation area on the functional surface 2a of the device chip 2, a roof layer 4 formed on the support layer 3 and working together with the functional surface 2a and the support layer 3 to form a sealing space 10 for the resonator 7, and a number of heat dissipation bumps 5 formed on the roof layer 4. At least the support area of ​​the heat dissipation bumps 5 in the roof layer 4 is formed as an uneven portion 17 by covering a base portion 17a, which is made uneven by a number of fine recesses 17b, with a seed metal layer 13.

Description

Technical Field

[0001] This invention relates to an improvement of an elastic wave device suitable for use as a frequency filter or the like in mobile communication devices and the like.

Background Art

[0002] An elastic wave (Surface Acoustic Wave / SAW) device having a WLP (Wafer Level Package) structure has the structure shown in Patent Document 1. In this Patent Document 1, a cover is provided on one surface of a device chip, and an IDT electrode formed on the one surface is positioned in an internal space formed by this cover. Here, when a signal is input to the elastic wave device, heat is generated in the device chip. However, the piezoelectric body constituting the device chip has a low thermal conductivity and poor heat dissipation. The thermal conductivity of lithium tantalate or lithium niobate used as the piezoelectric body is about 4 to 6 W / mK.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The main problem to be solved by this invention is to provide a new structure capable of appropriately improving the heat dissipation of a device chip constituting this type of elastic wave device having a WLP structure.

Means for Solving the Problems

[0005] In order to achieve the above object, in this invention, from a first aspect, the elastic wave device is A device chip comprising a functional surface made of a piezoelectric material, with a circuit pattern including multiple resonators, A support layer formed in a region other than the resonator formation region on the functional surface, A roof layer formed on the support layer and working in cooperation with the functional surface and the support layer to form a sealing space for the resonator, It comprises a number of heat dissipation bumps formed on the roof layer, At least the support area for the heat dissipation bumps in the roof layer is made up of a base portion that is unevenly shaped by numerous fine recesses, and is covered with a seed metal layer to form an uneven surface.

[0006] One embodiment of the present invention is to have a plurality of the aforementioned sealing spaces, and to provide a plurality of heat dissipation bumps such that, when viewed from a direction perpendicular to the functional surface, at least a portion of at least one of the heat dissipation bumps is located directly above each of the plurality of sealing spaces.

[0007] Furthermore, the device has multiple sealing spaces, and when viewed from a direction perpendicular to the functional surface, each of the multiple sealing spaces is configured to have a width and a length. One embodiment of this invention is to provide a number of heat dissipation bumps such that the distance between adjacent heat dissipation bumps is smaller than the width of the sealing space.

[0008] Furthermore, in order to achieve the above objectives, in this invention, from a second perspective, the method for manufacturing an elastic wave device according to the first perspective is described as follows: The steps include forming the circuit pattern in each region of the wafer that will become one of the device chips, The step of forming the support layer, The step of forming the roof layer, The steps include forming the base portion on the roof layer, The steps include: covering the base portion with the seed metal layer to form the uneven portion; The method includes the step of forming the heat dissipation bumps on the aforementioned uneven surface.

[0009] In the above manufacturing method, the roof layer is made of a photosensitive resin, The step of forming the base portion on the roof layer is, An exposure step in which a mask is used to form a predetermined dissolvable pattern on the roof layer, consisting of a plurality of fine dissolvable areas that dissolve during development and an insoluble area directly beneath it that does not dissolve during development, One embodiment of this invention is to include a developing step that forms a base portion with an uneven surface by dissolving and removing the soluble portion to form a large number of fine recesses.

[0010] Furthermore, in the exposure process, one embodiment of this invention involves forming the predetermined dissolvable pattern using a fine light-shielding portion or a fine light-transmitting portion formed on the mask. [Effects of the Invention]

[0011] According to this invention, the heat dissipation bump can be integrated with the roof layer by inserting its base into each of the multiple recesses that constitute the uneven portion in its support area, thereby giving its base a shape complementary to the uneven portion. Therefore, the contact area between the heat dissipation bump and the roof layer via the seed metal layer is ensured to be as large as possible. This makes it possible to effectively increase the adhesion strength between the heat dissipation bump and the roof layer. When an elastic wave device is mounted on the mounting surface of a support substrate such as a module board, fixed to connecting bumps, the heat generated in the device chip due to the input of a signal to the elastic wave device can be efficiently transferred and dissipated to the support substrate side through the numerous heat dissipation bumps in contact with the mounting surface. In addition, when a sealing resin or an underfill material is filled between the support substrate and the elastic wave device in a state where the elastic wave device is mounted on the support substrate, a force acting in a direction to narrow the distance between the roof layer and the functional surface acts on the roof layer at the location where the sealing space is formed. However, the deformation of the roof layer due to the action of such a force is effectively suppressed by the heat dissipation bumps fixed to the support substrate in a state of being firmly integrated with the roof layer.

Brief Description of Drawings

[0012] [Figure 1] FIG. 1 is a plan configuration diagram of an elastic wave device according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged plan configuration diagram of the upper right part of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional configuration diagram taken along the line A-A in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional configuration diagram showing a state where an elastic wave device is mounted on a support substrate. [Figure 5] FIG. 5 is a cross-sectional configuration diagram showing one step of the manufacturing process of the elastic wave device. [Figure 6] FIG. 6 is a cross-sectional configuration diagram showing one step of the manufacturing process of the elastic wave device carried out following the step of FIG. 5. [Figure 7] FIG. 7 is a cross-sectional configuration diagram showing one step of the manufacturing process of the elastic wave device carried out following the step of FIG. 6. [Figure 8] FIG. 8 is a cross-sectional configuration diagram showing one step of the manufacturing process of the elastic wave device carried out following the step of FIG. 7. [Figure 9] FIG. 9 is a cross-sectional configuration diagram showing the main part of the step of FIG. 8. [Figure 10] FIG. 10 is a cross-sectional configuration diagram showing the main part when a dissolvable pattern is formed by a method different from that of FIG. 9 in the step of FIG. 8. [Figure 11] FIG. 11 is a plan configuration diagram showing an example of the dissolvable pattern. [Figure 12] FIG. 12 is a plan configuration diagram showing another example of the dissolvable pattern. [Figure 13] Figure 13 is a plan view showing yet another example of the dissolution pattern. [Figure 14] Figure 14 is a cross-sectional view showing one step in the manufacturing process of the elastic wave device, which is carried out following the process shown in Figure 8. [Figure 15] Figure 15 is a cross-sectional view showing one step in the manufacturing process of the elastic wave device, which is carried out following the process shown in Figure 14. [Figure 16] Figure 16 is a cross-sectional view showing one step in the manufacturing process of the elastic wave device, which is carried out following the process shown in Figure 15. [Figure 17] Figure 17 is a plan view of the main components showing an example of the configuration of a resonator formed on the functional surface of a device chip. [Figure 18] Figure 18 is a diagram showing an example of a circuit formed on the functional surface of a device chip. [Modes for carrying out the invention]

[0013] A typical embodiment of this invention will be described below with reference to Figures 1 to 18. The elastic wave device 1 according to this embodiment is suitable for use as a frequency filter in mobile communication equipment and the like.

[0014] As shown in Figure 3, such an elastic wave device 1 comprises a device chip 2, a support layer 3, a roof layer 4, heat dissipation bumps 5, and connection bumps 6.

[0015] The device chip 2 has a circuit pattern including multiple resonators 7 on a functional surface 2a made of piezoelectric material.

[0016] Specifically, the device chip 2 has a flattened hexahedron shape with a functional surface 2a, a back surface 2b opposite to the functional surface 2a, and four sides 2c extending between the functional surface 2a and the back surface 2b.

[0017] Typically, lithium tantalate or lithium niobate are used as the piezoelectric material. Device chip 2 may also be constructed by stacking materials such as sapphire, silicon, alumina, spinel, quartz, or glass on the piezoelectric material.

[0018] The circuit pattern includes a plurality of resonators 7, pads 8 for external connection, inter-resonator wiring (not shown) connecting the resonators 7 to each other, and external connection wiring (not shown) connecting the resonators 7 to the pads 8. Such a circuit pattern is typically formed on the functional surface 2a by a conductive metal film formed by photolithography.

[0019] Figure 17 shows an example of the configuration of one resonator 7. The resonator 7 has an IDT electrode 7a and a reflector 7b formed so as to sandwich the IDT electrode 7a. The IDT electrode 7a consists of electrode pairs, and each electrode pair is formed by connecting multiple electrode fingers 7c, which are arranged in parallel so that their length intersects the propagation direction x of the elastic wave that becomes the main mode, with a busbar 7d at one end of each pair. The reflector 7b is formed by connecting the ends of multiple electrode fingers 7e, which are arranged in parallel so that their length intersects the propagation direction x of the elastic wave, with a busbar 7f.

[0020] Figure 18 shows a conceptual example of a circuit that can be provided on a single device chip 2 using the circuit pattern described above. Reference numeral 70 indicates a resonator 7 connected in series between the signal input / output terminals, reference numeral 71 indicates a resonator 7 connected in parallel between the signal input / output terminals, and reference numeral 9 indicates ground. The number and arrangement of resonators 7 can be changed as needed. In other words, the circuit in Figure 18 constitutes a ladder-type filter.

[0021] The support layer 3 is typically made of an insulating resin. The support layer 3 is formed in an area of ​​the functional surface 2a other than the area where the resonator 7 is formed. The area where the resonator 7 is formed is surrounded by the support layer 3.

[0022] The roof layer 4 is typically made of an insulating resin. The roof layer 4 is formed on the support layer 3 and works in cooperation with the functional surface 2a and the support layer 3 to form the sealing space 10 of the resonator 7. In the illustrated example, multiple sealing spaces 10 are formed on the functional surface 2a. Multiple resonators 7 may be located within a single sealing space 10. The roof layer 4 is supported by the support layer 3, with a distance equal to the thickness of the support layer 3 between it and the functional surface 2a. Outside the sealing space 10, vias 11 are formed that penetrate the roof layer 4 and the support layer 3, with the pad 8 positioned at the bottom of the hole.

[0023] A via wiring 12 (pillar) is formed inside the via 11. One end of the via wiring 12 is connected to the pad 8. The other end of the via wiring 12 is flush with the surface 4a of the roof layer 4.

[0024] The connecting bumps 6 are formed on the other end of the via wiring 12 via a seed metal layer 13. The connecting bumps 6 are made of solder or conductive metal, and in the illustrated example, as shown in Figure 1, when the device chip 2 is viewed from a direction perpendicular to its functional surface 2a, they are provided at each of the four corners 2d of the functional surface 2a, which has a rectangular outline, as well as one provided between adjacent corners 2d at one of the two edges 2e along the long side direction of the functional surface 2a, and two provided with a gap between adjacent corners 2d at the other of the two edges 2e along the long side direction of the functional surface 2a, for a total of seven.

[0025] In the illustrated example, as shown in Figure 1, the seven connecting bumps 6 and the numerous heat dissipation bumps 5 described later are regularly provided on the elastic wave device 1 by arranging a bump row 14 in a direction parallel to one side of the functional surface 2a (the short side direction in Figure 1) and arranging multiple bump rows 14 in a direction parallel to the side perpendicular to the aforementioned side of the functional surface 2a (the long side direction in Figure 1). In addition, the bump row 14 extending between two of the four corners 2d of the functional surface 2a (the rightmost bump row 14 in Figure 1) has one fewer bump than the other bump rows 14, and a gap of one bump is formed to the side of the connecting bump 6 located at one end of the bump row 14 (the lower right corner in Figure 1). As a result, in the illustrated example, the empty area 15 allows the automatic mounting machine (chip mounter) to recognize the orientation of the elastic wave device 1.

[0026] Numerous heat dissipation bumps 5 are formed on the roof layer 4. The heat dissipation bumps 5 are made of a material with high thermal conductivity. Typically, the heat dissipation bumps 5 are made of solder, copper (Cu), nickel (Ni), etc.

[0027] In the illustrated example, the connecting bump 6 and the heat dissipation bump 5 have substantially circular cross-sections in orientation along the functional surface 2a of the device chip 2 at any position in their protruding direction. Furthermore, in the state before mounting onto a support substrate 16 such as a module substrate (see Figure 4) (see Figure 3), the connecting bump 6 and the heat dissipation bump 5 are formed such that the cross-sectional area gradually decreases towards their protruding ends, exhibiting a dome shape.

[0028] In the illustrated example, the connecting bump 6 is fixed to a pad (not shown) formed on the mounting surface 16a of the support substrate 16 by a known method such as reflow soldering, thereby connecting the circuit on the support substrate 16 side with the circuit pattern of the device chip 2. In addition, each of the numerous heat dissipation bumps 5 is fixed to the mounting surface 16a of the support substrate 16 by a known method such as reflow soldering.

[0029] In this embodiment, at least the support area for the heat dissipation bump 5 in the roof layer 4 is an uneven portion 17 formed by covering a base portion 17a, which is made uneven by accumulating a large number of fine recesses 17b, with a seed metal layer 13. In the illustrated example, the uneven portion 17 has a rough surface. Although not shown in the diagram, the entire surface 4a (outer surface) of the roof layer 4 on the side opposite to the inner surface facing the sealing space 10 and where the heat dissipation bump 5 is formed may be the uneven portion 17.

[0030] The uneven portion 17 is formed by creating the recesses 17b with a predetermined gap between adjacent recesses 17b. The recess 17b is formed to a depth that does not penetrate the roof layer 4, typically 5 to 20 μm deep. Furthermore, the recesses 17b are formed with a distance of 5 to 20 μm between them. Figures 11 and 12 show examples in which the recesses 17b are formed in a point-like manner when viewed from a direction perpendicular to the surface 4a of the roof layer 4. In Figure 11, the numerous recesses 17b give the uneven surface 17 a substantially hexagonal outer shape, while in Figure 12, the numerous recesses 17b give the uneven surface 17 a substantially rectangular outer shape. The area of ​​these recesses 17b in the direction parallel to the surface 4a of the roof layer 4 is formed to be 5 to 20 μm. Figure 13 shows an example in which the recesses 17b are formed in a linear shape. In Figure 13, by arranging a large number of recesses 17b side by side, the uneven portion 17 has a substantially hexagonal outer shape. The width of these recesses 17b is formed to be 5 to 20 μm. Such uneven surfaces 17 only need to be formed such that fine recesses 17b and portions that are considered to be relatively protruding between adjacent recesses 17b are repeated in an orientation parallel to the surface 4a of the roof layer 4, and the shape of the recesses 17b can be set as needed.

[0031] The seed metal layer 13 is typically formed to have a thickness of 0.1 to 0.2 μm. The seed metal layer 13 is also typically composed of a titanium and copper laminate with a titanium substrate.

[0032] As shown in Figure 3, the heat dissipation bump 5 is integrated with the roof layer 4 by having its base 5a fit into each of the multiple recesses 17b in its support region, and having its base 5a shaped to complement the uneven portion 17. Therefore, the contact area between the heat dissipation bump 5 and the roof layer 4 via the seed metal layer 13 is ensured to be as large as possible. This makes it possible to effectively increase the adhesion strength between the heat dissipation bump 5 and the roof layer 4. When the elastic wave device 1 is mounted on the mounting surface 16a of the support substrate 16 by fixing it to the connecting bumps 6, the heat generated in the device chip 2 due to the input of a signal to the elastic wave device 1 can be efficiently transferred and dissipated to the support substrate 16 side through the numerous heat dissipation bumps 5 that are in contact with the mounting surface 16a. Furthermore, as shown in Figure 4, when the elastic wave device 1 is mounted on the support substrate 16 and a sealing resin or underfill material is filled between them, a force (indicated by the sign f in Figure 4) acts on the roof layer 4 at the location where the sealing space 10 is formed, which reduces the distance between the roof layer 4 and the functional surface 2a. However, the heat dissipation bumps 5, which are firmly integrated with the roof layer 4 and fixed to the support substrate 16, effectively suppress deformation of the roof layer 4 due to the action of such forces.

[0033] As shown in Figure 2, when viewed from a direction perpendicular to the functional surface 2a, each of the multiple sealing spaces 10 is configured to have a width and a length, and the numerous heat dissipation bumps are provided such that the distance d between adjacent heat dissipation bumps 5 is smaller than the width w of the sealing space 10. The distance d between adjacent heat dissipation bumps 5 refers to the distance between adjacent heat dissipation bumps 5 in a single bump row 14, and the distance between adjacent bump rows 14. In this way, when viewed from a direction perpendicular to the functional surface 2a, it becomes possible to provide a number of heat dissipation bumps 5 such that at least a portion of one of the heat dissipation bumps 5 is located directly above each of the multiple sealing spaces 10. This allows the heat generated in the device chip 2 by the input of a signal to the elastic wave device 1 to be transferred to the support substrate 16 side via the shortest distance through the heat dissipation bumps 5.

[0034] Typically, the device chip 2 is configured to be a rectangular plate with sides of 0.5 to 1 mm and a thickness of 0.15 to 0.2 mm. Furthermore, the support layer 3 typically has a thickness of 10 to 20 μm. Furthermore, the roof layer 4 typically has a thickness of 30 to 50 μm. In each figure, the thickness of the components of the elastic wave device 1 is exaggerated to make it easier to understand the device's structure.

[0035] The elastic wave device 1 described above can be manufactured appropriately and efficiently by the following manufacturing process.

[0036] First, the circuit pattern including the resonator 7 is formed in each region of the wafer 18 that will become the device chip 2 (first step / Figure 5).

[0037] Next, the support layer 3 is formed (second step / Figure 6). Typically, the support layer 3 is formed by coating the wafer 18 with the materials constituting the support layer 3, followed by photolithography and etching.

[0038] Next, the roof layer 4 is formed (third step / Figure 7). The roof layer 4 is typically formed by laminating a photosensitive resin onto the wafer 18.

[0039] Next, the base portion 17a is formed on the roof layer 4 (fourth step / Figures 8 and 14). Along with this, the fourth step is an exposure process (Figures 9 and 10) in which a predetermined dissolvable pattern 20 is formed on the roof layer 4 using a mask 19 (see Figures 9 and 10), consisting of a plurality of fine dissolvable parts 20a that dissolve during development, with an insoluble part 20b directly beneath that does not dissolve during development. The process includes a developing step (Figure 14) in which a large number of fine recesses 17b are formed by dissolving and removing the soluble portion 20a, thereby forming the uneven base portion 17a. In other words, each soluble portion 20a is formed to extend from the surface 4a of the roof layer 4 to a certain range in the thickness direction. Furthermore, the space between each soluble portion 20a and the inner surface of the roof layer 4 is defined as a non-soluble portion 20b. A predetermined soluble pattern 20 is formed by the collection of multiple fine soluble portions 20a formed in this way. In this way, it becomes possible to form the via 11 (see Figure 14) simultaneously with the base portion 17a without increasing the number of manufacturing steps.

[0040] In the exposure step, it is preferable to form the predetermined dissolvable pattern 20 using the fine light-shielding portion 19a or the fine light-transmitting portion 19b formed on the mask 19. Specifically, a fine light-shielding portion 19a or a fine light-transmitting portion 19b is formed on a pattern formed on a light-transmitting substrate that will serve as a mask 19.

[0041] Figure 9 shows an example in which a fine light-shielding portion 19a is formed on the mask 19, and Figure 10 shows an example in which a fine light-transmitting portion 19b is formed. In Figures 9 and 10, the mask 19 is shown in a simplified form, and for the sake of explanation, the mask 19 is shown directly above the roof layer 4. However, normally the mask 19 is located at a required position between the light source and the roof layer 4, and the pattern on the mask 19 is reduced in size and projected onto the roof layer 4. Specifically, Figure 9 shows the case where the resin constituting the photosensitive resin layer 14 is negative type, and Figure 10 shows the case where the resin constituting the photosensitive resin layer 14 is positive type.

[0042] In Figures 9 and 10, the thick lines emphasize the shadows produced during the aforementioned exposure.

[0043] When forming the point-shaped recess 17b, the fine light-shielding portion 19a or the fine light-transmitting portion 19b is formed in a point shape. At the same time, the size of the projected image im on the photosensitive resin layer 14 based on the fine light-shielding portion 19a or the fine light-transmitting portion 19b is set to a dimension less than the resolution limit of the resin constituting the photosensitive resin layer 14. In other words, the size of the projected image im is made smaller than the minimum size (resolution limit) at which the area directly below the projected image im becomes a dissolvable portion 20a. This makes it possible to form the dissolvable pattern 20 below the projected image im.

[0044] Furthermore, when forming the linear recess 17b, the fine light-shielding portion 19a or the fine light-transmitting portion 19b is formed in a linear shape. At the same time, the width of the projected image im on the photosensitive resin layer 14 based on the fine light-shielding portion 19a or the fine light-transmitting portion 19b is set to a dimension less than the resolution limit of the resin constituting the photosensitive resin layer 14. In other words, the width of the projected image im is made smaller than the minimum dimension (resolution limit) at which the entire area directly below the projected image im becomes a dissolvable portion 20a. This makes it possible to form the dissolvable pattern 20 below the projected image im.

[0045] When the resin constituting the photosensitive resin layer 14 is negative type (Figure 9), a non-exposure-exposure layer can be formed directly below the location where the projected image im is formed in the fine light-shielding portion 19a. The upper non-exposure portion can then function as the dissolvable portion 20a.

[0046] When the resin constituting the photosensitive resin layer 14 is of the positive type (Figure 10), an exposed-unexposed layer can be formed directly beneath the projected image im of the fine light-transmitting portion 19b. This upper exposed portion can then function as the dissolvable portion 20a.

[0047] Next, the base portion 17a is covered with the seed metal layer 13 to form the uneven portion 17 (5th step / Figure 15). In the illustrated example, the surface 4a of the roof layer 4, including over the via wiring 12, is covered with the seed metal layer 13. The seed metal layer 13 is typically formed by sputtering.

[0048] Next, the heat dissipation bumps 5 are formed on the uneven portion 17 (step 6 / Figure 16). Reference numeral 21 in the figure indicates a resist layer that covers areas other than the base portion 17a and the area where the via internal wiring 12 is formed. With the resist layer 21 formed in this manner, the bump constituent material is filled into the areas not covered by the resist layer 21, and the heat dissipation bumps 5 and connecting bumps 6 are formed by performing a reflow process or the like. For the heat dissipation bumps 5, their base portions 5a are inserted into each of the multiple recesses 17b in their support area, and the base portions 5a are integrated with the roof layer 4 in a shape that is complementary to the uneven portion 17.

[0049] Finally, the seed metal layer 13 in areas other than the resist layer 21 and the heat dissipation bumps 5 and connecting bumps 6 is removed, and the wafer 18 is cut into regions that will form a single elastic wave device 1, thereby generating multiple elastic wave devices 1 from the wafer 18 (Figures 1 to 3).

[0050] Naturally, the present invention is not limited to the embodiments described above, but includes all embodiments that can achieve the objectives of the present invention. [Explanation of symbols]

[0051] x propagation direction d distance w width 1. Elastic wave device 2 device chips 2a Functional aspect 2b Back 2c side 2d corner 2e Edge 3 Support layer 4. Roof layer 4a surface 5. Heat dissipation bumps 5a base 6. Connecting bumps 7, 70, 71 resonator 7a IDT electrode 7b reflector 7c electrode finger 7d bus bar 7e electrode finger 7F Bus Bar 8 pads 9 Grand 10 Sealed space 11 Beer 12 via internal wiring 13 Seed Metal Layer 14 Bump Rows 15 Free space 16 Support substrate 16a Mounting surface 17 Uneven part 17a Base section 17b recess 18 wafers 19 masks 19a Fine light-shielding section 19b Fine transparent part 20 dissolvable patterns 20a Dissolvable part 20b Non-dissolvable part 21 Resist Layers

Claims

1. A device chip comprising a functional surface made of a piezoelectric material, with a circuit pattern including multiple resonators, A support layer formed in a region other than the resonator formation region on the functional surface, A roof layer formed on the support layer and working in cooperation with the functional surface and the support layer to form a sealing space for the resonator, It comprises a number of heat dissipation bumps formed on the roof layer, An elastic wave device in which at least the support area of ​​the heat dissipation bump in the roof layer is an uneven portion formed by covering a base portion, which is made uneven by a large number of fine recesses, with a seed metal layer.

2. The elastic wave device according to claim 1, further comprising a plurality of sealing spaces, and provided with a number of heat dissipation bumps such that, when viewed from a direction perpendicular to the functional surface, at least a portion of one of the heat dissipation bumps is located directly above each of the plurality of sealing spaces.

3. The device has multiple sealing spaces, and when viewed from a direction perpendicular to the functional surface, each of the multiple sealing spaces is configured to have a width and a length. The elastic wave device according to claim 1, wherein a number of heat dissipation bumps are provided such that the distance between adjacent heat dissipation bumps is smaller than the width of the sealing space.

4. A method for manufacturing an elastic wave device according to any one of claims 1 to 3, The steps include forming the circuit pattern in each region of the wafer that will become one of the device chips, The step of forming the support layer, The step of forming the roof layer, The steps include forming the base portion on the roof layer, The steps include: covering the base portion with the seed metal layer to form the uneven portion; A method for manufacturing an elastic wave device, comprising the step of forming the heat dissipation bumps on the uneven portion.

5. The roof layer is made of a photosensitive resin, The step of forming the base portion on the roof layer is, An exposure step in which a mask is used to form a predetermined dissolvable pattern on the roof layer, consisting of a plurality of fine dissolvable areas that dissolve during development and an insoluble area directly beneath it that does not dissolve during development, A method for manufacturing an elastic wave device according to claim 4, comprising a developing step of forming a base portion that is made uneven by dissolving and removing the soluble portion to form a large number of fine recesses.

6. The method for manufacturing an elastic wave device according to claim 5, wherein in the exposure step, the predetermined dissolvable pattern is formed by a fine light-shielding portion or a fine light-transmitting portion formed on the mask.

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