Filtering device and method for forming a filtering device

Abstract

A filter device and a method for forming a filter device, the filter device comprising: a substrate, the substrate comprising a first region and a second region surrounding the first region; a plurality of device structures on the first region; a plurality of connection pads on the first region, the connection pads electrically connected to the device structures; a first bump on each of the plurality of connection pads; a first metal layer on the substrate, the first metal layer on the second region, the first metal layer surrounding the first region, the first metal layer for sealing the plurality of device structures; a carrier substrate, the carrier substrate comprising a first electrical interconnect structure, the first bump engaged with the first electrical interconnect structure to form an electrical connection. The reliability of the filter device is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a filter device and a forming method of the filter device. BACKGROUND

[0002] A radio frequency (RF) front-end chip of a wireless communication device includes a power amplifier, an antenna switch, a radio frequency filter, a multiplexer, and a low noise amplifier, etc. Among them, the radio frequency filter includes a surface acoustic wave (SAW) filter, a bulk acoustic wave (BAW) filter, a micro-electro-mechanical system (MEMS) filter, an integrated passive device (IPD) filter, etc.

[0003] As the wireless communication technology gradually evolves, the use range of the wireless communication device is wider and wider, and the reliability requirement of the filter is higher and higher. As the filter widely used in the current wireless communication device, the SAW and BAW filter with high reliability can prolong the service life of the device and expand the use range. The packaging process of the filter will affect the reliability of the SAW and BAW filter. SUMMARY

[0004] The technical problem solved by the present application is to provide a filter device and a forming method of the filter device to improve the reliability of the filter device.

[0005] To solve the above technical problem, the technical scheme of the present application provides a filter device, comprising: a substrate, the substrate comprising a first area and a second area surrounding the first area; a plurality of device structures located on the first area; a plurality of connection pads located on the first area, the connection pads being electrically connected with the device structures; a first bump located on each of the connection pads; a first metal layer located on the substrate, the first metal layer being located on the second area, the first metal layer surrounding the first area, and the first metal layer being used for sealing the plurality of device structures; a carrier plate, the carrier plate comprising a first electrical interconnection structure, and the first bump and the first electrical interconnection structure being engaged to form an electrical connection.

[0006] Optionally, the filter device further comprises a second bump located on the first area, and the second bump is used for heat dissipation.

[0007] Optionally, the top surfaces of the first bump, the first metal layer, and the second bump are flush.

[0008] Optionally, the material of the first bump comprises tin or gold; the material of the first metal layer comprises copper or gold; the material of the second bump comprises copper or gold.

[0009] Optionally, the carrier substrate further comprises a first bonding structure and a first thermal conductive structure, the first bonding structure is bonded with the first metal layer, and the first thermal conductive structure is bonded with the second bump.

[0010] Optionally, the carrier substrate comprises opposite first and second surfaces, the first surface exposes the surface of the first electrical interconnection structure, the surface of the first bonding structure and the surface of the first thermal conductive structure, and the first electrical interconnection structure penetrates through the carrier substrate; the first bump, the first metal layer and the second bump are towards the first surface.

[0011] Optionally, further comprising: a first bonding layer on the surface of the first bump, a second bonding layer on the surface of the first metal layer and a third bonding layer on the surface of the second bump; the first bonding layer is connected with the first electrical interconnection structure, and the first bump is bonded with the first electrical interconnection structure through the first bonding layer; the second bonding layer is connected with the first bonding structure, and the first metal layer is bonded with the first bonding structure through the second bonding layer; the third bonding layer is connected with the first thermal conductive structure, and the second bump is bonded with the first thermal conductive structure through the third bonding layer.

[0012] Optionally, the material of the first bonding layer, the second bonding layer and the third bonding layer comprises solder tin, tin-lead alloy solder tin, solder tin with antimony, solder tin with cadmium, solder tin with silver or solder tin with copper; the material of the first electrical interconnection structure, the first bonding structure and the first thermal conductive structure comprises metal, and the metal comprises gold.

[0013] Optionally, the percentage of the number of atoms of gold element in the total number of atoms of gold and tin ranges from 78% to 82%, and the percentage of the number of atoms of tin element in the total number of atoms of gold and tin ranges from 18% to 22%.

[0014] Optionally, the difference between the thermal expansion coefficients of the material of the substrate and the material of the carrier substrate is less than 20ppm / ℃.

[0015] Optionally, the device structure comprises an active structure of a surface acoustic wave resonator or an active structure of a bulk acoustic wave resonator.

[0016] Optionally, the device structure comprises an interdigital transducer.

[0017] Optionally, the material of the substrate comprises piezoelectric material, and the piezoelectric material comprises lithium tantalate, lithium niobate, quartz, zinc oxide or aluminum nitride; the substrate and the device structure constitute a surface acoustic wave resonator structure.

[0018] Optionally, further comprising: a plurality of cavities embedded in the substrate, openings of the cavities being located on a surface of the substrate, and the plurality of device structures respectively corresponding to the plurality of cavities.

[0019] Optionally, the device structure comprises a first electrode layer located above or inside the cavity, a piezoelectric layer located on the first electrode layer, and a second electrode layer located on the piezoelectric layer; and the substrate and the device structure form a bulk acoustic wave resonator structure.

[0020] Optionally, the material of the carrier board comprises organic resin, epoxy resin, glass fiber, polyimide, cyanate ester, polytetrafluoroethylene, or ceramic.

[0021] Correspondingly, the present application also provides a forming method of the filter device, comprising: providing a substrate, the substrate comprising a first area and a second area surrounding the first area; forming a plurality of device structures on the first area; forming a plurality of connection pads on the first area, the connection pads being electrically connected with the device structures; forming a plurality of first bumps on the connection pads respectively; forming a first metal layer on the substrate, the first metal layer being located on the second area, the first metal layer surrounding the first area and being used for sealing the device structures; providing a carrier board, the carrier board comprising a first electrical interconnection structure; and bonding the substrate and the carrier board, comprising: bonding the first bumps and the first electrical interconnection structure, the first bumps being electrically connected with the first electrical interconnection structure.

[0022] Optionally, before the bonding of the substrate and the carrier board, the method further comprises: forming second bumps on the first area, the second bumps being used for heat dissipation.

[0023] Optionally, top surfaces of the first bumps, the first metal layer, and the second bumps are flush.

[0024] Optionally, the method of forming the first bumps, the first metal layer, and the second bumps comprises: forming initial first bumps on the connection pads; forming an initial first metal layer on the second area; forming initial second bumps on the first area; and planarizing the initial first bumps, the initial first metal layer, and the initial second bumps to form the first bumps, the first metal layer, and the second bumps.

[0025] Optionally, the carrier board further comprises a first bonding structure; and the bonding of the substrate and the carrier board further comprises: bonding the first bonding structure and the first metal layer.

[0026] Optionally, the carrier board further comprises a first heat conduction structure; and the bonding of the substrate and the carrier board further comprises: bonding the first heat conduction structure and the second bumps.

[0027] Optionally, the carrier plate includes opposite first and second surfaces, the first surface exposes the first electrically interconnecting structure surface, the first bonding structure surface and the first thermally conductive structure surface, and the first electrically interconnecting structure penetrates the carrier plate.

[0028] Optionally, the method of bonding the substrate and the carrier plate includes: forming a first bonding layer on the first bump surface, a second bonding layer on the first metal layer surface and a third bonding layer on the second bump surface; moving the first bump, the first metal layer and the second bump towards the first surface, bonding the first bonding layer and the first electrically interconnecting structure, the first bump and the first electrically interconnecting structure are electrically connected through the first bonding layer, bonding the second bonding layer and the first bonding structure, the first metal layer and the first bonding structure are bonded through the second bonding layer, bonding the third bonding layer and the first thermally conductive structure, the second bump and the first thermally conductive structure are bonded through the third bonding layer.

[0029] Optionally, the substrate includes a device region and a dicing lane region, the device region includes the first region and the second region; before bonding the substrate and the carrier plate, the method further includes: cutting the substrate along the dicing lane region.

[0030] Optionally, the substrate includes a device region and a dicing lane region, the device region includes the first region and the second region; after bonding the substrate and the carrier plate, the method further includes: cutting the bonded substrate and carrier plate along the dicing lane region.

[0031] Optionally, forming the plurality of device structures on the first region includes: forming a plurality of active structures of surface acoustic wave resonators on the first region or forming a plurality of active structures of bulk acoustic wave resonators on the first region.

[0032] Optionally, forming the plurality of device structures on the first region includes: forming a plurality of interdigital transducers on the first region.

[0033] Optionally, the material of the substrate includes piezoelectric material, the piezoelectric material includes: lithium tantalate, lithium niobate, quartz, zinc oxide or aluminum nitride; the substrate and the device structures constitute a surface acoustic wave resonator structure.

[0034] Optionally, the method further includes: forming a plurality of cavities embedded in the substrate, the openings of the cavities are located on the surface of the substrate, and the plurality of device structures correspond to the plurality of cavities respectively.

[0035] Optionally, forming the plurality of device structures on the first region comprises: forming a plurality of first electrode layers on the first region, respectively above or in the plurality of cavities; forming a piezoelectric layer on the plurality of first electrode layers; and forming a plurality of second electrode layers on the piezoelectric layer, respectively corresponding to the plurality of first electrode layers; and the substrate and the device structures form a bulk acoustic resonator structure.

[0036] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0037] In the technical scheme of the present application, the plurality of first bumps are respectively on the plurality of connecting pads in the first region, the first metal layer surrounds the first region, the first metal layer is tightly bonded to the carrier plate, so that the first metal layer and the carrier plate form a sealed space, which can protect the plurality of device structures on the first region from water vapor and impurities.

[0038] Further, the top surfaces of the first bumps, the first metal layer and the second bumps are flush, so that when the substrate and the carrier plate are bonded, the first bumps, the first bonding structure and the first metal layer, and the first heat-conducting structure and the second bumps can be bonded at the same time, which can simplify the process flow.

[0039] Further, by directly bonding the substrate carrying the plurality of device structures and the carrier plate without introducing a packaging substrate to package the device structures, the overall thickness of the filter device after bonding is reduced; at the same time, the substrate can be cut along the cutting path region before bonding the substrate and the carrier plate; or the substrate and the carrier plate can be cut along the cutting path region after bonding the substrate and the carrier plate, which simplifies the process and is more flexible, and is conducive to improving production efficiency.

[0040] Further, the difference between the coefficients of thermal expansion of the material of the substrate and the material of the carrier plate is less than 20ppm / ℃, so that thermal mismatch between the substrate and the carrier plate does not cause warping, which in turn affects the packaging yield. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figures 1 to 7 is a structural schematic diagram of a filter device forming process in an embodiment of the present application;

[0042] Figure 8 and Figure 9 is a structural schematic diagram of a filter device forming process in another embodiment of the present application. DETAILED DESCRIPTION

[0043] As described in the background section, the packaging process of a filter device can affect its reliability.

[0044] The packaging process for the filter device is as follows: Solder joints are electroplated onto the filter device to form a bonding layer. Then, the filter device is flip-chip bonded to the packaging substrate, and an organic film is used to cover the filter device, forming a cavity. This organic film blocks moisture and impurities. Finally, the packaged filter device is placed on a carrier board and electrically connected to other RF devices. The packaged filter device is relatively thick, and due to the poor water resistance of the organic film, the reliability of the packaged filter device needs to be improved.

[0045] This invention provides a filtering device and a method for forming the filtering device. A plurality of first bumps are respectively located on a plurality of connecting pads in a first region, and a first metal layer surrounds the first region. The first metal layer is tightly bonded to the carrier plate, thereby protecting the plurality of device structures in the first region from corrosion by moisture and impurities.

[0046] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] Figures 1 to 7 This is a schematic diagram of the formation process of the filter device in one embodiment of the present invention.

[0048] Please refer to Figure 1 and Figure 2 , Figure 1 for Figure 2 Top view, Figure 2 for Figure 1 A cross-sectional view along the AA1 direction, the cross-sectional structure having both interdigitated transducers and connecting disks, providing a substrate 200, the substrate 200 including a device region and a dicing region, the device region including a first region I and a second region II surrounding the first region I.

[0049] Please continue to refer to this. Figure 1 and Figure 2 Several device structures are formed on the first region I.

[0050] The device structure includes: an active structure of a surface acoustic wave resonator or an active structure of a bulk acoustic wave resonator.

[0051] In this embodiment, the device structure includes an interdigital transducer 201.

[0052] The substrate 200 and the device structure constitute a piezoelectric surface acoustic wave (SAW) resonator.

[0053] The material of the interdigital transducer 201 comprises a metal or a metal alloy; the metal comprises a combination of one or more of copper, aluminum, magnesium, molybdenum, gold, platinum, titanium, tungsten, cobalt, nickel, and tantalum.

[0054] In this embodiment, the material of the interdigital transducer 201 comprises titanium aluminum.

[0055] In this embodiment, the substrate 200 comprises a piezoelectric material, which comprises lithium tantalate (LiTaO3, abbreviated as LT), lithium niobate (LiNbO3, abbreviated as LN), quartz, zinc oxide (ZnO), or aluminum nitride (AlN), etc.

[0056] Please continue to refer to Figure 1 and Figure 2 A plurality of connection pads 202 are formed on the first region I, and the connection pads 202 are electrically connected to the interdigital transducer 201.

[0057] The material of the connection pad 202 comprises aluminum, gold, platinum, titanium, or copper.

[0058] Please refer to Figure 3 and Figure 4 , Figure 4 is a schematic view based on Figure 2 , Figure 3 is a schematic view based on Figure 1 A plurality of first bumps 203 are formed on the substrate 200, and the plurality of first bumps 203 are respectively located on the plurality of connection pads 202; a first metal layer 204 is formed on the substrate 200, the first metal layer 204 is located on the second region II, and the first metal layer 204 surrounds the first region I.

[0059] The first metal layer 204 surrounds the first region I, so that the first metal layer 204 can protect the plurality of device structures on the first region I, avoiding the erosion of water vapor or impurities on the plurality of device structures in the subsequent working process.

[0060] It should be noted that the first bump 203 and the first metal layer 204 can play a role in heat dissipation, but the heat dissipation capacity needs to be further enhanced under high power. In this embodiment, a plurality of second bumps 205 are formed on the first region I for enhancing the heat dissipation capacity.

[0061] In this embodiment, the top surfaces of the first bump 203, the first metal layer 204, and the second bump 205 are flush.

[0062] The method of forming the first bump 203, the first metal layer 204 and the second bump 205 includes: forming an initial first bump (not shown) on the connecting disk 202; forming an initial first metal layer (not shown) on the second region II; forming an initial second bump (not shown) on the first region I; planarizing the initial first bump, the initial first metal layer and the initial second bump to form the first bump 203, the first metal layer 204 and the second bump 205.

[0063] The top surfaces of the first bump 203, the first metal layer 204, and the second bump 205 are flush. The first bump 203, the first metal layer 204, and the second bump 205 can be formed simultaneously in one planarization process, thereby saving process steps.

[0064] The material of the first bump 203 includes tin or gold; the material of the first metal layer 204 includes copper or gold; and the material of the second bump 205 includes copper or gold.

[0065] Please refer to Figure 5 , Figure 5 In order to be in Figure 3 Based on the schematic diagram, a first bonding layer 206 is formed on the top surface of the first bump 203, a second bonding layer 207 is formed on the top surface of the first metal layer 204, and a third bonding layer 208 is formed on the top surface of the second bump 205.

[0066] The materials of the first bonding layer 206, the second bonding layer 207 and the third bonding layer 208 include solder, tin-lead alloy solder, antimony-added solder, cadmium-added solder, silver-added solder or copper-added solder.

[0067] Please refer to Figure 6 A carrier board 300 is provided, the carrier board 300 including a first electrical interconnect structure 302.

[0068] In this embodiment, the carrier plate 300 further includes a first bonding structure 301 and a first heat-conducting structure 303.

[0069] In this embodiment, the carrier plate 300 includes a first surface and a second surface opposite to each other. The first surface exposes the first surface of the first electrical interconnect structure 302, the surface of the first bonding structure 301 and the surface of the first thermally conductive structure 303, and the first electrical interconnect structure 302 penetrates the carrier plate 300.

[0070] The first electrical interconnect structure 302 extends through the carrier plate 300, and the second surface exposes the second surface of the first electrical interconnect structure 302 for electrical connection with external circuitry.

[0071] In the embodiment, the difference between the thermal expansion coefficients of the material of the substrate 200 and the material of the carrier 300 is less than 20ppm / ℃. Thus, the thermal mismatch between the substrate 200 and the carrier 300 is avoided to generate warping, which further affects the packaging yield.

[0072] In the embodiment, the material of the carrier 300 includes organic resin, epoxy resin, glass fiber, polyimide, cyanate ester, polytetrafluoroethylene or ceramic.

[0073] Please refer to Figure 7 The substrate 200 is bonded with the carrier 300, and the first bump 203 is bonded with the first electrical interconnection structure 302. It should be noted that the first electrical interconnection structure 302 is electrically connected with the first bump 203, and the first electrical interconnection structure 302 is also electrically connected with external circuit.

[0074] In the embodiment, the first bump 203 is bonded with the first electrical interconnection structure 302, the first bonding structure 301 is bonded with the first metal layer 204, and the first heat conduction structure 303 is bonded with the second bump 205.

[0075] The first bonding structure 301 is bonded with the first metal layer 204, so that the first metal layer 204 is closely bonded with the carrier 300, thereby forming a sealed space between the first metal layer 204 and the carrier 300, which can protect the device structures on the first region I from water vapor and impurities.

[0076] The top surfaces of the first bump 203, the first metal layer 204 and the second bump 205 are flush, so that when the substrate 200 is bonded with the carrier 300, the first bump 203 is bonded with the first electrical interconnection structure 302, the first bonding structure 301 is bonded with the first metal layer 204, and the first heat conduction structure 303 is bonded with the second bump 205, which can simplify the process flow.

[0077] The first heat conduction structure 303 is bonded with the second bump 205, so that the first heat conduction structure 303 can conduct the heat generated by the filtering device away through the second bump 205. It should be noted that the first electrical interconnection structure 302 and the first bonding structure 301 can also play a role in heat dissipation, but the heat dissipation capacity needs to be further improved under high power.

[0078] The bonding of the substrate 200 and the carrier plate 300 comprises: moving the first bump 203, the first metal layer 204 and the second bump 205 towards the first surface; connecting the first bonding layer 206 and the first electrical interconnection structure 302, the first bump 203 and the first electrical interconnection structure 302 being bonded by the first bonding layer 206; connecting the second bonding layer 207 and the first bonding structure 301, the first metal layer 204 and the first bonding structure 301 being bonded by the second bonding layer 207; connecting the third bonding layer 208 and the first thermal conduction structure 303, the second bump 205 and the first thermal conduction structure 303 being bonded by the third bonding layer 208.

[0079] The material of the first electrical interconnection structure 302, the first bonding structure 301 and the first thermal conduction structure 303 comprises metal, and the metal comprises gold or copper.

[0080] The material of the first bonding layer 206, the second bonding layer 207 and the third bonding layer 208 comprises tin.

[0081] In the embodiment, the percentage of the number of atoms of gold in the total number of atoms of gold and tin ranges from 78% to 82%, and the percentage of the number of atoms of tin in the total number of atoms of gold and tin ranges from 18% to 22%.

[0082] In the embodiment, after the bonding of the substrate 200 and the carrier plate 300, the method further comprises: cutting the bonded substrate 200 and carrier plate 300 along the cutting path to form a separate filter device.

[0083] In other embodiments, before the bonding of the substrate and the carrier plate, the method further comprises: cutting the substrate along the cutting path to form a separate wafer carrying a plurality of device structures.

[0084] By directly bonding the substrate 200 carrying a plurality of device structures and the carrier plate 300, the device structures are not encapsulated by an encapsulation substrate, so that the overall thickness of the bonded filter device is reduced; at the same time, the substrate 200 can be cut along the cutting path before the bonding of the substrate and the carrier plate; or the bonded substrate 200 and the carrier plate 300 can be cut along the cutting path after the bonding of the substrate 200 and the carrier plate 300, so that the process is more simplified and flexible, and the production efficiency is improved.

[0085] Correspondingly, the embodiment of the application also provides a filter device, please continue to refer to Figure 7 , comprising:

[0086] a substrate 200, the substrate 200 comprising a first region I and a second region II surrounding the first region I;

[0087] a plurality of device structures on the first region I;

[0088] a plurality of connection pads 202 on the first region I, the connection pads 202 electrically connected with the device structures;

[0089] a plurality of first bumps 203 on the connection pads 202 respectively;

[0090] a first metal layer 204 on the substrate 200, the first metal layer 204 on the second region II, the first metal layer 204 surrounding the first region I, the first metal layer for protecting the device structures;

[0091] a carrier 300 bonded with the substrate 200, the carrier 300 comprising a first electrical interconnection structure 302, the first bumps 203 bonded with the first electrical interconnection structure 302 to form electrical connections.

[0092] In the embodiment, the carrier 300 further comprises a plurality of second bumps 205 on the first region I.

[0093] In the embodiment, top surfaces of the first bumps 203, the first metal layer 204 and the second bumps 205 are flush.

[0094] In the embodiment, the material of the first bumps 203 comprises tin or gold; the material of the first metal layer 204 comprises copper or gold; and the material of the second bumps 205 comprises copper or gold.

[0095] In the embodiment, the carrier 300 further comprises a first bonding structure 301 and a first thermal conductive structure 303, the first bonding structure 301 bonded with the first metal layer 204, and the first thermal conductive structure 303 bonded with the second bumps 205.

[0096] In the embodiment, the carrier 300 comprises opposite first and second faces, the first face exposing first surfaces of the first electrical interconnection structure 302, the first bonding structure 301 and the first thermal conductive structure 303, and the first electrical interconnection structure 302 penetrating through the carrier 300; the first bumps 203, the first metal layer 204 and the second bumps 205 facing the first face of the carrier 300.

[0097] In the embodiment, the first bonding layer 206 is located on the top surface of the first bump 203, the second bonding layer 207 is located on the top surface of the first metal layer 204, and the third bonding layer 208 is located on the top surface of the second bump 205; the first bonding layer 206 is connected with the first electric interconnection structure 302, and the first bump 203 is bonded with the first electric interconnection structure 302 through the first bonding layer 206; the second bonding layer 207 is connected with the first bonding structure 301, and the first metal layer 204 is bonded with the first bonding structure 301 through the second bonding layer 207; the third bonding layer 208 is connected with the first thermal conduction structure 303, and the second bump 205 is bonded with the first thermal conduction structure 303 through the third bonding layer 208.

[0098] In the embodiment, the materials of the first bonding layer 206, the second bonding layer 207 and the third bonding layer 208 include solder, tin-lead alloy solder, solder with antimony, solder with cadmium, solder with silver or solder with copper; the materials of the first electric interconnection structure 302, the first bonding structure 301 and the first thermal conduction structure 303 include metal, and the metal includes gold.

[0099] In the embodiment, the percentage of the atomic number of gold element in the total atomic number of gold and tin ranges from 78% to 82%, and the percentage of the atomic number of tin element in the total atomic number of gold and tin ranges from 18% to 22%.

[0100] In the embodiment, the difference between the thermal expansion coefficients of the material of the substrate 200 and the material of the carrier plate 300 is less than 20ppm / ℃.

[0101] The device structure includes an active structure of a surface acoustic wave resonator or an active structure of a bulk acoustic wave resonator.

[0102] In the embodiment, the device structure includes the interdigital transducer 201.

[0103] In the embodiment, the material of the substrate 200 includes piezoelectric material, and the piezoelectric material includes lithium tantalate, lithium niobate, quartz, zinc oxide or aluminum nitride; the substrate 200 and the device structure constitute a surface acoustic wave resonator.

[0104] In the embodiment, the material of the carrier plate 300 includes organic resin, epoxy resin, glass fiber, polyimide, cyanate ester, polytetrafluoroethylene or ceramic.

[0105] Figure 8 and Figure 9 The structure diagram of the process of forming the filtering device is shown in another embodiment of the application.

[0106] Please refer to Figure 8 andFigure 9 , Figure 8 is a top view of the structure in Figure 9 , Figure 9 is a schematic structural view of the structure in the direction of section line BB1 in Figure 8 , Figure 9 The difference between the structure in Figure 2 and the structure in is that the filter device further comprises a plurality of cavities 401 embedded in the substrate 400, the openings of the cavities 401 are located on the surface of the substrate 400, and the plurality of device structures correspond to the plurality of cavities 401 respectively; and a plurality of connecting pads 405 located on the first region I.

[0107] In the embodiment, the material of the substrate 400 comprises silicon.

[0108] In the embodiment, the device structure comprises a first electrode layer 402 located above or inside the cavity 401, a piezoelectric layer 403 located on the first electrode layer 402, and a second electrode layer 404 located on the piezoelectric layer 403.

[0109] In the embodiment, the material of the piezoelectric layer 403 comprises lithium tantalate, lithium niobate, quartz, zinc oxide or aluminum nitride.

[0110] The substrate 400 and the device structure constitute a bulk acoustic wave (BAW) resonator.

[0111] Next, the process of forming the connecting pad, the first bump, the first metal layer, the second bump, the first electrical interconnection structure, the first bonding structure, the first heat conduction structure and the bonding of the substrate and the carrier plate on the substrate can refer to the content of Figures 1 to 7 , which will not be described here.

[0112] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art, without departing from the spirit and scope of the present application, can make various changes and modifications, therefore the protection scope of the present application should be limited by the scope defined by the claims.

Claims

1. A filtering device, characterized in that, The substrate comprises a first region and a second region surrounding the first region; a plurality of device structures on the first region; a plurality of connection pads on the first region, the connection pads being electrically connected with the device structures; a plurality of first bumps respectively on the connection pads; a first metal layer on the substrate, the first metal layer being on the second region, the first metal layer surrounding the first region, and the first metal layer being used for sealing the device structures; a carrier plate comprising a first electrical interconnection structure, the first bumps being engaged with the first electrical interconnection structure to form an electrical connection; the carrier plate further comprises a first engagement structure, the first engagement structure being engaged with the first metal layer. Further comprising:

2. The filtering device of claim 1, wherein, a second bump on the first region, the second bump being used for heat dissipation. The top surfaces of the first bumps, the first metal layer and the second bump are flush.

3. The filter device of claim 2, wherein, The material of the first bumps comprises tin or gold; the material of the first metal layer comprises copper or gold; and the material of the second bump comprises copper or gold.

4. The filter device of claim 2, wherein, The carrier plate further comprises a first heat conduction structure, the first heat conduction structure being engaged with the second bump.

5. The filtering device of claim 2, wherein, The carrier plate comprises opposite first and second faces, the first face exposing surfaces of the first electrical interconnection structure, the first engagement structure and the first heat conduction structure, and the first electrical interconnection structure penetrating through the carrier plate; 6. The filtering device of claim 5, wherein, The first bumps, the first metal layer and the second bump are towards the first face. Further comprising:

7. The filtering device of claim 5, wherein, a first engagement layer on the surface of the first bump, a second engagement layer on the surface of the first metal layer and a third engagement layer on the surface of the second bump; The first engagement layer is connected with the first electrical interconnection structure, and the first bump is engaged with the first electrical interconnection structure through the first engagement layer; The second engagement layer is connected with the first engagement structure, and the first metal layer is engaged with the first engagement structure through the second engagement layer; The third engagement layer is connected with the first heat conduction structure, and the second bump is engaged with the first heat conduction structure through the third engagement layer. The material of the first, second and third engagement layers comprises solder, tin-lead alloy solder, solder with antimony, solder with cadmium, solder with silver or solder with copper; and the material of the first electrical interconnection structure, the first engagement structure and the first heat conduction structure comprises metal, and the metal comprises gold.

8. The filtering device of claim 7, wherein, The percentage of the number of atoms of gold element in the total number of atoms of gold and tin ranges from 78% to 82%, and the percentage of the number of atoms of tin element in the total number of atoms of gold and tin ranges from 18% to 22%.

9. The filtering device of claim 8, wherein, The difference between the coefficients of thermal expansion of the material of the substrate and the material of the carrier plate is less than 20ppm / ℃.

10. The filtering device of claim 1, wherein, The device structure comprises an active structure of a surface acoustic wave resonator or an active structure of a bulk acoustic wave resonator.

11. The filtering device of claim 1, wherein, The device structure comprises an interdigital transducer.

12. The filtering device of claim 1, wherein, The material of the substrate comprises piezoelectric material, and the piezoelectric material comprises lithium tantalate, lithium niobate, quartz, zinc oxide or aluminum nitride; the substrate and the device structure constitute a surface acoustic wave resonator.

13. The filtering device of claim 12, wherein, Further comprising:

14. The filtering device of claim 1, wherein, ​ A plurality of cavities embedded in the substrate, openings of the cavities being located on a surface of the substrate, a plurality of the device structures respectively corresponding to a plurality of the cavities.

15. The filtering device of claim 14, wherein, The device structure comprises a first electrode layer located above or inside the cavity, a piezoelectric layer located on the first electrode layer, and a second electrode layer located on the piezoelectric layer; the substrate and the device structure constitute a bulk acoustic wave resonator.

16. The filtering device of claim 10, wherein, The material of the carrier board comprises organic resin, epoxy resin, glass fiber, polyimide, cyanate ester, polytetrafluoroethylene or ceramic.

17. A method of forming a filter device, characterized by Comprise: A substrate is provided, the substrate comprising a first region and a second region surrounding the first region; A plurality of device structures are formed on the first region; A plurality of connecting pads are formed on the first region, the connecting pads being electrically connected with the device structures; A plurality of first bumps are respectively formed on a plurality of the connecting pads; A first metal layer is formed on the substrate, located on the second region, the first metal layer surrounding the first region, for sealing a plurality of the device structures; A carrier board is provided, the carrier board comprising a first electrical interconnection structure; Bonding the substrate and the carrier board comprises: bonding the first bumps and the first electrical interconnection structure, the first bumps being electrically connected with the first electrical interconnection structure; The carrier board further comprises a first bonding structure; bonding the substrate and the carrier board further comprises: bonding the first bonding structure and the first metal layer.

18. The method of forming a filter device of claim 17, wherein, Before bonding the substrate and the carrier board, further comprising: forming second bumps on the first region, the second bumps being used for heat dissipation.

19. The method of forming a filter device of claim 18, wherein, The top surfaces of the first bumps, the first metal layer and the second bumps are flush.

20. The method of forming a filter device of claim 19, wherein, Forming the first bumps, the first metal layer and the second bumps comprises: forming initial first bumps on the connecting pads; forming an initial first metal layer on the second region; forming initial second bumps on the first region; planarizing the initial first bumps, the initial first metal layer and the initial second bumps to form the first bumps, the first metal layer and the second bumps.

21. The method of forming a filter device of claim 18, wherein, The carrier board further comprises a first heat conduction structure; bonding the substrate and the carrier board further comprises: bonding the first heat conduction structure and the second bumps.

22. The method of forming a filter device of claim 21, wherein, The carrier board comprises opposite first and second faces, the first face exposing surfaces of the first electrical interconnection structure, the first bonding structure and the first heat conduction structure, and the first electrical interconnection structure penetrating through the carrier board.

23. The method of forming a filter device of claim 22, wherein, The method of bonding the substrate and the carrier includes: forming a first bonding layer on the first bump surface, forming a second bonding layer on the first metal layer surface, and forming a third bonding layer on the second bump surface; moving the first bump, the first metal layer, and the second bump towards the first surface; connecting the first bonding layer and the first electrical interconnection structure, the first bump and the first electrical interconnection structure being bonded by the first bonding layer; connecting the second bonding layer and the first bonding structure, the first metal layer and the first bonding structure being bonded by the second bonding layer; connecting the third bonding layer and the first thermal conduction structure, the second bump and the first thermal conduction structure being bonded by the third bonding layer.

24. The method of forming a filter device of claim 17, wherein, The substrate includes a device region and a scribe lane region, the device region including the first region and the second region; before bonding the substrate and the carrier, the method further includes: cutting the substrate along the scribe lane region.

25. The method for forming the filtering device as described in claim 17, characterized in that, The substrate includes a device region and a scribe lane region, the device region including the first region and the second region; after bonding the substrate and the carrier, the method further includes: cutting the bonded substrate and the carrier along the scribe lane region.

26. The method for forming the filtering device as described in claim 17, characterized in that, Forming a plurality of device structures on the first region includes: forming a plurality of active structures of surface acoustic wave resonators on the first region or forming a plurality of active structures of bulk acoustic wave resonators on the first region.

27. The method of forming a filter device of claim 17, wherein, Forming a plurality of device structures on the first region includes: forming a plurality of interdigital transducers on the first region.

28. The method of forming a filter device of claim 27, wherein, The material of the substrate includes a piezoelectric material, the piezoelectric material including: lithium tantalate, lithium niobate, quartz, zinc oxide, or aluminum nitride; the substrate and the device structures constitute a surface acoustic wave resonator.

29. The method of forming a filter device of claim 17, wherein, Further comprising: A plurality of cavities are formed embedded in the substrate, openings of the cavities are located on the surface of the substrate, and a plurality of the device structures correspond to a plurality of the cavities respectively.

30. The method of forming a filter device of claim 29, wherein, Forming a plurality of device structures on the first region includes: forming a plurality of first electrode layers on the first region, respectively located above or inside a plurality of the cavities; forming a piezoelectric layer on a plurality of the first electrode layers; and forming a plurality of second electrode layers on the piezoelectric layer, respectively corresponding to a plurality of the first electrode layers; the substrate and the device structures constitute a bulk acoustic wave resonator structure.

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