Elastic wave device and method for manufacturing same

Abstract

This elastic wave device is provided with: a device chip provided with a circuit pattern including a plurality of resonators on a functional surface comprising a piezoelectric body; a support layer formed on the functional surface in a region other than the resonator formation region; the roof layer is formed on the supporting layer and interacts with the functional surface and the supporting layer to form a sealed space of the resonator; and a plurality of heat dissipation bumps formed on the roof layer, in which at least a region for supporting the heat dissipation bumps in the roof layer is provided as a concavo-convex portion in which a concavo-convex base having a plurality of fine concavities is covered with a seed metal layer. The invention provides a novel structure capable of properly improving the heat dissipation performance of a device chip of an elastic wave device with a WLP structure.

Description

Technical Field

[0001] This invention relates to an elastic wave device, and more particularly to an improved technique for an elastic wave device suitable for use as a frequency filter in mobile communication devices. Background Technology

[0002] Surface Acoustic Wave (SAW) devices with a WLP (Wafer Level Package) structure have the structure shown in Patent Document 1.

[0003] In the technology described in Patent Document 1, a cover is provided on one side of the device chip, and an IDT electrode formed on that side is provided in the internal space formed by the cover.

[0004] In this case, the device chip generates heat when a signal is input to the elastic wave device, and the piezoelectric material constituting the device chip has low thermal conductivity, resulting in poor heat dissipation. The thermal conductivity of lithium tantalate or lithium niobate used as piezoelectric materials is approximately 4–6 W / m•K.

[0005] Patent document 1: Japanese Patent Application Publication No. 2002-217673. Summary of the Invention

[0006] The main problem to be solved by this invention is to provide a novel structure in elastic wave devices of this type of WLP structure that can appropriately improve the heat dissipation performance of the device chip constituting the device.

[0007] To address the aforementioned issues, this invention, from a first perspective, provides an elastic wave device comprising: A device chip with a circuit pattern containing multiple resonators is located on a functional surface made of piezoelectric material. A support layer formed on the functional surface in a region other than the region where the resonator is formed; A roof layer formed on the support layer, which, together with the functional surface and the support layer, forms the sealed space of the resonator; And a plurality of protrusions for heat dissipation formed on the roof layer; In the roof layer, at least the area used to support the heat dissipation protrusions is set as a concave-convex portion, which is formed by covering a concave-convex base with multiple micro-concave portions with a seed metal layer.

[0008] One embodiment of the present invention is that the elastic wave device has a plurality of the sealed spaces and, when viewed from a direction perpendicular to the functional surface, is equipped with a plurality of the above-mentioned heat dissipation bumps, and these heat dissipation bumps satisfy the following condition: at least one portion of the heat dissipation bump is located directly above any one of the plurality of sealed spaces.

[0009] Furthermore, another embodiment of the present invention is that: the elastic wave device has a plurality of sealed spaces, and when viewed from a direction perpendicular to the functional surface, the plurality of sealed spaces each have a width and a length, and the plurality of heat dissipation bumps are arranged such that the spacing between adjacent heat dissipation bumps is less than the width of the sealed space.

[0010] Another embodiment of the present invention is that the depth of the recess in the protrusion does not penetrate the roof layer.

[0011] Another embodiment of the present invention is that the depth of the recess is 5 to 20 μm.

[0012] In another embodiment of the present invention, the spacing between adjacent recesses in the plurality of recesses and protrusions is 5 to 20 μm.

[0013] Another embodiment of the present invention is that the heat dissipation bump is formed in the direction of its protruding end with a gradually decreasing cross-sectional area, and the whole is dome-shaped.

[0014] Furthermore, in order to solve the above-mentioned problems, the present invention, from a second perspective, provides a method for manufacturing an elastic wave device as described in the first perspective above. The method includes the following steps: The step of forming the circuit pattern on each region of the wafer that serves as the chip of the device; The step of forming the support layer; The steps for forming the roof layer; The step of forming the base on the roof layer; The step of covering the base with the seed metal layer to form the uneven portion; The step of forming the heat dissipation bump on the concave and convex portions.

[0015] In one embodiment, in the above manufacturing method, the roof layer is composed of a photosensitive resin. The step of forming the base on the roof layer includes: By using a mask, the roof layer is exposed to form a predetermined soluble pattern consisting of multiple fine soluble portions that are soluble during development and non-soluble portions that are insoluble during development directly below them. And a development process that forms a base with an uneven structure by dissolving and removing the soluble portion to form multiple micro-recesses.

[0016] Furthermore, in the exposure process, the predetermined soluble pattern is formed by providing fine light-blocking or fine light-transmitting portions on the photomask.

[0017] According to the present invention, the base of the heat dissipation bump can be embedded in a plurality of recesses forming the protrusion and concave portion within its support region, and the shape of the base is complementary to the protrusion and concave portion, thereby enabling it to be integrated with the roof layer. Therefore, the contact area between the heat dissipation bump and the roof layer through the seed metal layer can be maximized, thereby effectively improving the bonding strength between the heat dissipation bump and the roof layer.

[0018] When the elastic wave device is mounted on the support substrate by fixing the connecting bumps to the mounting surface of the support substrate such as the module substrate, the heat generated by the input signal to the elastic wave device can be efficiently conducted to the support substrate side and released through multiple heat dissipation bumps in contact with the mounting surface.

[0019] Furthermore, when the elastic wave device is mounted on the support substrate and encapsulation resin or bottom filler material is filled between the two, although the roof layer will be subjected to a force in the direction that reduces the distance between it and the functional surface in the area forming the sealed space, the deformation of the roof layer under this force can be effectively suppressed because the heat dissipation bumps are firmly integrated with the roof layer and fixed to the support substrate. Attached Figure Description

[0020] Figure 1 This is a top view of an elastic wave device according to one embodiment of the present invention.

[0021] Figure 2 yes Figure 1 Enlarged top-down structural diagram of the upper right section.

[0022] Figure 3 yes Figure 2 A cross-sectional view of the location along line A-A in the middle.

[0023] Figure 4 This is a cross-sectional structural diagram showing the state of the elastic wave device mounted on the support substrate.

[0024] Figure 5 This is a cross-sectional structural diagram showing one step in the manufacturing process of the elastic wave device.

[0025] Figure 6 It is immediately following Figure 5 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0026] Figure 7 It is immediately following Figure 6 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0027] Figure 8 It is immediately following Figure 7 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0028] Figure 9 It means Figure 8 The cross-sectional structural diagram of the key part in the process shown.

[0029] Figure 10 It means in Figure 8 In the process shown, with Figure 9 Cross-sectional structural diagrams of key parts when different methods are used to form soluble patterns.

[0030] Figure 11 This is a top view of one embodiment of the soluble pattern.

[0031] Figure 12 This is a top view of another embodiment of the soluble pattern.

[0032] Figure 13 This is a top view of another embodiment of the soluble pattern.

[0033] Figure 14 It is immediately following Figure 8 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0034] Figure 15 It is immediately following Figure 14 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0035] Figure 16 It is immediately following Figure 15 A cross-sectional view of one of the steps in the manufacturing process of elastic wave devices after the shown step.

[0036] Figure 17 This is a top view of a key part of a resonator structure example formed on the functional surface of a device chip.

[0037] Figure 18 This is a structural diagram showing an example of a circuit formed on the functional surface of a device chip.

[0038] Figure label: x direction of propagation d Distance w width 1. Elastic wave device 2. Device Chips 2a Functional surface 2b Back 2c Side View 2D corner 2e Edge 3 Support layer 4. Roof layer 4a surface 5. Heat dissipation bumps 5a Base 6 Connecting bumps 7, 70, 71 resonators 7a IDT electrode 7b Reflector 7c electrode finger 7d busbar 7e electrode finger 7f busbar 8 pads 9. Ground terminal (GND) 10 Sealed Space 11 Through Holes 12 Wiring inside through-holes 13 Seed Metal Layer 14 bump columns 15 Vacant Areas 16 Supporting substrate 16a Mounting Surface 17. Uneven parts 17a Base 17b recess 18 wafers 19 Masks 19a Fine light-shielding section 19b Micro-transmitting part 20 Soluble Patterns 20a Soluble portion 20b Insoluble portion 21. Anti-corrosion layer. Detailed Implementation

[0039] The following will refer to Figures 1 to 18 Typical embodiments of the present invention will be described below. The elastic wave device 1 according to this embodiment is suitable for use as a frequency filter in mobile communication devices and the like.

[0040] like Figure 3As shown, the elastic wave device 1 includes: a device chip 2, a support layer 3, a roof layer 4, a heat dissipation bump 5, and a connection bump 6.

[0041] The device chip 2 has a circuit pattern containing multiple resonators 7 on the functional surface 2a made of piezoelectric material.

[0042] Specifically, the device chip 2 is in the shape of a flat hexahedron, having a functional surface 2a, a back surface 2b opposite to the functional surface 2a, and four side surfaces 2c connecting the functional surface 2a and the back surface 2b.

[0043] Lithium tantalate or lithium niobate can typically be used as the piezoelectric element.

[0044] The device chip 2 can also be constructed by stacking materials such as sapphire, silicon, alumina, spinel, quartz or glass on the piezoelectric body.

[0045] The circuit pattern includes multiple resonators 7, pads 8 for external connections, inter-resonator wiring (not shown in the figure) for connecting the resonators 7, and external connection wiring (not shown in the figure) for connecting the resonators 7 to the pads 8. The circuit pattern is typically formed on the functional surface 2a by a conductive metal film formed by photolithography.

[0046] Figure 17 An example of the configuration of a resonator 7 is shown. The resonator 7 has an IDT electrode 7a and reflectors 7b formed on both sides of the IDT electrode 7a. The IDT electrode 7a consists of a pair of electrodes, each pair consisting of multiple electrode fingers 7c. These electrode fingers are arranged parallel to each other with their length direction intersecting the propagation direction x of the main mode of the elastic wave, and are interconnected at one end by a busbar 7d. The reflector 7b consists of multiple electrode fingers 7e. These electrode fingers are also arranged parallel to each other with their length direction intersecting the propagation direction x of the elastic wave, and are interconnected at their ends by a busbar 7f.

[0047] Figure 18 An example of a circuit formed by the aforementioned circuit pattern and disposed on a device chip 2 is schematically illustrated. Reference numeral 70 indicates a resonator 7 connected in series between the signal input and output terminals, reference numeral 71 indicates a resonator 7 connected in parallel between the signal input and output terminals, and reference numeral 9 indicates ground. The number and configuration of the resonators 7 can be changed as needed. In other words, through... Figure 18 The circuit shown can be used to construct a trapezoidal filter.

[0048] The support layer 3 is typically made of insulating resin. The support layer 3 is formed on the functional surface 2a in the area excluding the region where the resonator 7 is formed. The support layer 3 surrounds the region where the resonator 7 is formed.

[0049] The roof layer 4 is typically made of insulating resin. The roof layer 4 is formed on the support layer 3 and works together with the functional surface 2a and the support layer 3 to form a sealed space 10 for encapsulating the resonator 7. In the illustrated example, multiple sealed spaces 10 are formed on the functional surface 2a. Multiple resonators 7 can also be accommodated within a single sealed space 10. The roof layer 4 is supported by the support layer 3, maintaining a distance between it and the functional surface 2a equal to the thickness of the support layer 3. A through-hole 11 is formed outside the sealed space 10, penetrating the roof layer 4 and the support layer 3, with the solder pad 8 located at the bottom of the through-hole.

[0050] A through-hole wiring 12 (columnar structure) is formed within the through-hole 11. One end of the through-hole wiring 12 is connected to the pad 8, and the other end is flush with the surface 4a of the roof layer 4.

[0051] A connecting bump 6 is formed on the other end of the wiring 12 within the through-hole through a seed metal layer 13. The connecting bump 6 is made of solder or conductive metal.

[0052] In the illustrated example, such as Figure 1 As shown, when the device chip 2 is viewed from a direction perpendicular to the functional surface 2a, the connecting bumps 6 are provided at the four corners 2d of the functional surface 2a, which has a rectangular outline; in addition, one bump is provided between adjacent corners 2d on one side of the two edge portions 2e along the long side of the functional surface 2a, and two bumps are provided at intervals between adjacent corners 2d on the other side, for a total of 7 connecting bumps 6.

[0053] Furthermore, in the illustrated example, such as Figure 1 As shown, these seven connecting bumps 6, together with the multiple heat dissipation bumps 5 described later, are regularly arranged in the elastic wave device 1: the multiple bumps are arranged along a direction parallel to one side of the functional surface 2a ( Figure 1 A row of bumps 14 is formed by arranging the bumps along the shorter side (with the middle side as the guide), and multiple rows of these bumps 14 are arranged along a direction perpendicular to this side (with the middle side as the guide). Figure 1 The four sides of the functional surface 2a are arranged side by side (with the longer side in the middle). Furthermore, a row of protrusions 14 extends between two corners of the four corners 2d of the functional surface 2a. Figure 1 In the right-end bump column 14, the number of bumps contained is reduced by one compared to other bump columns 14, thereby making one side of the end of the bump column 14 ( Figure 1 A blank area of ​​the size of a bump is formed next to the connecting bump 6 (located in the lower right corner). With this setting, in the illustrated example, the blank area 15 enables the automatic placement equipment (chip placement machine) to identify the direction of the elastic wave device 1.

[0054] A plurality of 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 materials such as solder, copper (Cu), and nickel (Ni).

[0055] In the illustrated example, the connecting bump 6 and the heat dissipation bump 5, at any position in their protruding direction, have a substantially circular cross-section along the functional surface 2a of the device chip 2. Furthermore, before being mounted to the support substrate 16 such as the module substrate (see...), Figure 4 In the state of (see) Figure 3 The connecting protrusion 6 and the heat dissipation protrusion 5 are formed in a shape with gradually decreasing cross-sectional area in the direction of their protruding ends, and the whole is dome-shaped.

[0056] In the illustrated example, the connection 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 on the device chip 2. Furthermore, multiple heat dissipation bumps 5 are also fixed to the mounting surface 16a of the support substrate 16 by known methods such as reflow soldering.

[0057] In this embodiment, at least the area in the roof layer 4 used to support the heat dissipation protrusion 5 is configured as a raised / lowered portion 17, which is formed by covering a raised / lowered base 17a composed of a large number of micro-recesses 17b with a seed metal layer 13. In the illustrated example, the raised / lowered portion 17 has a rough surface. Although not shown in the figure, the surface 4a (outer surface) on the side of the roof layer 4 opposite to the inner surface facing the sealed space 10 and forming the heat dissipation protrusion 5 can also be entirely regarded as the raised / lowered portion 17.

[0058] The protrusions and recesses 17 are formed by creating a plurality of recesses 17b at predetermined intervals.

[0059] The depth of recess 17b does not penetrate the roof layer 4, and the typical terrain has a depth of 5 to 20 μm.

[0060] In addition, the spacing between adjacent recesses 17b is also set to 5 to 20 μm.

[0061] Figure 11 and Figure 12 An example of the configuration is shown where the recesses 17b are distributed in a dotted pattern when viewed from a direction perpendicular to the surface 4a of the roof layer 4.

[0062] exist Figure 11 In the middle, the concave-convex portion 17, composed of multiple recesses 17b, presents an overall hexagonal outer contour shape; while... Figure 12In the middle, the concave and convex portion 17 is composed of multiple concave portions 17b and presents an approximately quadrilateral outer contour shape.

[0063] In these recesses 17b, the width along the direction parallel to the surface 4a of the roof layer 4 is set to 5 to 20 μm.

[0064] Figure 13 An example of recess 17b being formed in a linear shape is shown. Figure 13 In this design, multiple recesses 17b are arranged side by side, giving the overall concave-convex portion 17 an approximately hexagonal outer contour shape. The width of these recesses 17b is also set to 5 to 20 μm.

[0065] This type of concave-convex part 17 can be formed by alternating multiple micro-concave parts 17b and opposite convex parts in the direction parallel to the surface 4a of the roof layer 4. The specific shape of the concave part 17b can be set as needed.

[0066] The seed metal layer 13 is typically formed to have a thickness of 0.1 to 0.2 μm. Furthermore, the seed metal layer 13 is typically composed of a laminated structure of titanium and copper with a titanium underlayer.

[0067] like Figure 3 As shown, in the support area of ​​the heat dissipation protrusion 5, its base 5a is embedded in a plurality of recesses 17b, and the shape of the base 5a is complementary to the protrusions and recesses 17b, thereby achieving integration with the roof layer 4.

[0068] Therefore, the contact area between the heat dissipation bump 5 and the roof layer 4 through the seed metal layer 13 can be increased as much as possible, thereby effectively improving the bonding strength between the heat dissipation bump 5 and the roof layer 4.

[0069] When the elastic wave device 1 is fixed to the mounting surface 16a of the support substrate 16 by the connecting bump 6 and the heat generated by the signal input to the elastic wave device 1 can be efficiently conducted to the support substrate 16 side and released through the multiple heat dissipation bumps 5 that are in contact with the mounting surface 16a.

[0070] In addition, such as Figure 4 As shown, after the elastic wave device 1 is mounted to the support substrate 16, when the encapsulating resin or bottom filler material is filled between the two, the roof layer 4 will be subjected to a force in the formation area of ​​the sealed space 10 in the direction that reduces the distance between it and the functional surface 2a. Figure 4 The force (in the direction indicated by the symbol f) acts on the roof layer 4, but since the heat dissipation protrusion 5 is firmly integrated with the roof layer 4 and fixed to the support base plate 16, the deformation of the roof layer 4 caused by the force can be effectively suppressed.

[0071] like Figure 2As shown, when viewed from a direction perpendicular to the functional surface 2a, the multiple sealed spaces 10 each have a width and a length, and the multiple heat dissipation protrusions 5 are arranged such that the distance d between adjacent heat dissipation protrusions 5 is less than the width w of the sealed space 10.

[0072] Here, the distance d between adjacent heat dissipation bumps 5 refers to both the spacing between adjacent heat dissipation bumps 5 within the same bump column 14 and the spacing between adjacent bump columns 14.

[0073] With the above arrangement, when viewed from a direction perpendicular to the functional surface 2a, at least a portion of at least one heat dissipation protrusion 5 can be arranged directly above each of the plurality of sealed spaces 10.

[0074] This allows the elastic wave device 1 to efficiently conduct heat to the support substrate 16 via the heat dissipation bumps 5 when receiving signal input and the device chip 2 generates heat.

[0075] Typically, the device chip 2 is configured as a rectangular plate structure with one side of 0.5 to 1 mm and a thickness of 0.15 to 0.2 mm.

[0076] The thickness of the support layer 3 is typically 10 to 20 μm.

[0077] The thickness of roof layer 4 is typically 30 to 50 μm.

[0078] In addition, in each figure, the thickness of the constituent elements has been exaggerated to facilitate understanding of the structure of the elastic wave device 1.

[0079] The elastic wave device 1 described above can be manufactured appropriately and reasonably through the following manufacturing process.

[0080] First, in the wafer 18 that will become the device chip 2, the circuit pattern containing the resonator 7 is formed in each region where the device chip 2 will be formed (first step / Figure 5 ).

[0081] Next, the support layer 3 is formed (second step / Figure 6 The support layer 3 is typically formed by coating the material constituting the support layer 3 onto the wafer 18 and then using photolithography and etching processes.

[0082] Then, the roof layer 4 is formed (third step / Figure 7 The roof layer 4 is typically formed by laminating a photosensitive resin onto wafer 18.

[0083] Next, the base 17a is formed on the roof layer 4 (fourth step / Figure 8 , Figure 14 ).

[0084] Meanwhile, this fourth step includes the following process: using mask 19 (see...) Figure 9 , Figure 10 An exposure process is used to form a predetermined soluble pattern 20 on the roof layer 4. This pattern consists of multiple fine soluble portions 20a that are soluble during development, with non-soluble portions 20b that are insoluble during development located below it. Figure 9 , Figure 10 ); And a developing process that removes the soluble portion 20a by developing, forming a plurality of fine recesses 17b, thereby obtaining the base 17a with an uneven structure. Figure 14 ).

[0085] In other words, each soluble portion 20a is formed within a certain range extending from the surface 4a of the roof layer 4 into its thickness direction; and an insoluble portion 20b is provided between each soluble portion 20a and the inner surface of the roof layer 4. The collection of multiple fine soluble portions 20a formed in this way constitutes the predetermined soluble pattern 20.

[0086] In this way, without adding manufacturing process steps, the base 17a and the through hole 11 (see...) can be connected. Figure 14 The synchronous formation of ).

[0087] In the exposure process, the predetermined soluble pattern 20 is preferably formed by forming fine light-blocking portions 19a or fine light-transmitting portions 19b on the mask 19.

[0088] Specifically, a pattern can be formed on a light-transmitting substrate that serves as a mask 19, and a fine light-blocking portion 19a or a fine light-transmitting portion 19b can be provided on the pattern.

[0089] Figure 9 An example of forming fine light-blocking portions 19a on the mask 19 is shown. Figure 10 An example of forming the fine light-transmitting portion 19b is shown. Figure 9 and Figure 10 In this illustration, the mask 19 is simplified and, for ease of explanation, is shown directly above the roof layer 4. However, in reality, the mask 19 is usually located at an appropriate position between the light source and the roof layer 4, and the pattern on it will be projected onto the roof layer 4 in a reduced manner.

[0090] Specifically, Figure 9 The image shows the case where a negative resin is used for the photosensitive resin layer 14, and... Figure 10 The image shows the case when using a positive resin.

[0091] Figure 9 andFigure 10 The thick lines are used to emphasize the shadows produced during the exposure process.

[0092] When forming the dotted recesses 17b, the fine light-blocking portions 19a or the fine light-transmitting portions 19b are formed in a dotted pattern. Simultaneously, the image im projected onto the photosensitive resin layer 14 based on the fine light-blocking portions 19a or the fine light-transmitting portions 19b is smaller than the resolution limit of the resin constituting the photosensitive resin layer 14.

[0093] In other words, the size of the projected image im is made smaller than the minimum size (i.e., the resolution limit) required to make the entire area directly below the projected image im a soluble part 20a. In this way, the soluble pattern 20 can be successfully formed below the projected image im.

[0094] Furthermore, when forming the linear recess 17b, the fine light-blocking portion 19a or the fine light-transmitting portion 19b is formed in a linear shape. Simultaneously, the width of the projected image im formed on the photosensitive resin layer 14 based on the fine light-blocking portion 19a or the fine light-transmitting portion 19b is less than the resolution limit of the resin constituting the photosensitive resin layer 14.

[0095] In other words, the width of the projected image im is made smaller than the minimum size (i.e., the resolution limit) required to form the entire area directly below it as the soluble part 20a. Therefore, the soluble pattern 20 can be successfully formed below the projected image im.

[0096] When the resin constituting the photosensitive resin layer 14 is negative ( Figure 9 An unexposed-exposed layer structure can be formed directly below the projection image im forming area of ​​the fine light-shielding part 19a. In this case, the upper unexposed portion can function as the soluble portion 20a.

[0097] When the resin constituting the photosensitive resin layer 14 is positive ( Figure 10 This allows for the formation of an exposed-unexposed layer structure directly below the projected image im of the micro-transparent portion 19b. In this case, the exposed portion on the upper side can function as the soluble portion 20a.

[0098] Next, the uneven portion 17 is formed by covering the base 17a with the seed metal layer 13 (fifth step / ). Figure 15 ).

[0099] In the illustrated example, the entire surface 4a of the roof layer 4, including the area above the wiring 12 within the through-hole, is covered by the seed metal layer 13.

[0100] The seed metal layer 13 is typically formed by sputtering.

[0101] Next, the heat dissipation protrusion 5 is formed on the uneven portion 17 (sixth step / ) Figure 16 In the figure, symbol 21 represents the anti-corrosion layer covering the area outside the region formed by the base 17a and the wiring 12 within the through hole. With the anti-corrosion layer 21 formed, the material constituting the bump is filled into the area not covered by the anti-corrosion layer 21, and heat dissipation bump 5 and connection bump 6 are formed by processes such as reflow soldering. Regarding the heat dissipation bump 5, in the support area, its base 5a is embedded in a plurality of the recesses 17b, and the shape of the base 5a is complementary to the recesses and protrusions 17b, thereby integrating it with the roof layer 4.

[0102] Finally, the resist layer 21 and the seed metal layer 13 located outside the areas where the heat dissipation bumps 5 and the connection bumps 6 are formed are removed, and the wafer 18 is cut into sections for each region that will constitute an elastic wave device 1, thereby obtaining multiple elastic wave devices 1 from the wafer 18 (see [reference]). Figures 1 to 3 ).

[0103] Furthermore, it is natural that the present invention is not limited to the embodiments described above, but includes all embodiments that can achieve the objectives of the present invention.

Claims

1. An elastic wave device, characterized in that, It possesses: The device chip has a circuit pattern containing multiple resonators on a functional surface made of piezoelectric material; A support layer is formed on the functional surface in a region other than the resonator formation region; The roof layer is formed on the support layer and works together with the functional surface and the support layer to form the sealed space of the resonator. And multiple heat dissipation protrusions formed on the roof layer, In the roof layer, at least the area used to support the heat dissipation protrusions is set as a concave-convex portion, which is formed by a concave-convex base with multiple micro-concave portions covered by a seed metal layer.

2. The elastic wave device as described in claim 1, characterized in that, It has multiple sealed spaces and, when viewed from a direction perpendicular to the functional surface, is equipped with multiple heat dissipation protrusions, wherein at least a portion of each heat dissipation protrusion is located directly above any one of the multiple sealed spaces.

3. The elastic wave device as described in claim 1, characterized in that, It has multiple sealing spaces, and when viewed from a direction perpendicular to the functional surface, each of the multiple sealing spaces has a width and a length. The multiple heat dissipation protrusions are arranged such that the distance between adjacent heat dissipation protrusions is less than the width of the sealing space.

4. The elastic wave device as described in claim 1, characterized in that, The depth of the recess in the protrusion does not penetrate the roof layer.

5. The elastic wave device as described in claim 4, characterized in that, The depth of the recess is 5 to 20 μm.

6. The elastic wave device as described in claim 1, characterized in that, Among the plurality of concave and convex portions, the distance between adjacent concave portions is 5 to 20 μm.

7. The elastic wave device as described in claim 1, characterized in that, The heat dissipation bump is formed in a shape with a gradually decreasing cross-sectional area in the direction of its protruding end, and the whole is dome-shaped.

8. A method for manufacturing any of the elastic wave devices as described in claims 1 to 7, characterized in that, Includes the following steps: The step of forming the circuit pattern on each region of the wafer that serves as the chip of the device; The step of forming the support layer; The steps for forming the roof layer; The step of forming the base on the roof layer; The step of covering the base with the seed metal layer to form the uneven portion; The step of forming the heat dissipation bump on the concave and convex portion.

9. The method for manufacturing the elastic wave device as described in claim 8, characterized in that: The roof layer is made of photosensitive resin. The step of forming the base on the roof layer includes: Using a mask, the roof layer is exposed to form the dissolution pattern, which consists of multiple micro-dissolvable portions that are soluble during development and non-dissolvable portions that are insoluble during development directly below it. And a development process that forms a base having an uneven structure by dissolving and removing the soluble portion to form multiple micro-recesses.

10. The method for manufacturing the elastic wave device as described in claim 9, characterized in that: In the exposure process, the predetermined soluble pattern is formed through the micro-shading or micro-transmitting parts provided on the mask.

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