Packaging structure and method of bulk acoustic wave resonator, bulk acoustic wave resonator device, filter and electronic equipment
By introducing a support layer and sealing ring design into the packaging structure of the FBAR device, and utilizing the connection between the release hole and the acoustic mirror cavity, the problems of large area and performance degradation of the FBAR device in the release process are solved, thereby achieving miniaturization and stable performance of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROFS MICROSYST TIANJIN CO LTD
- Filing Date
- 2020-09-04
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional RF filters are limited by structure and performance in high-frequency communication. FBAR devices have a large area in the release process and are easily affected by the release liquid, which leads to performance degradation and is not conducive to miniaturization.
The packaging structure incorporates a support layer and a sealing ring design. A release hole passes through the support layer and communicates with the acoustic mirror cavity to prevent the release fluid from contacting the resonator diaphragm. A through hole is provided at the gap of the sealing ring to reduce the device area.
This approach enables miniaturization and performance stability of FBAR devices, avoids the impact of release fluid on the film layer, and improves the sealing and reliability of the packaging structure.
Smart Images
Figure CN114142822B_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present invention relate to the semiconductor field, and more particularly to a packaging structure and packaging method for a bulk acoustic wave resonator, a bulk acoustic wave resonator device, a filter, and an electronic device. Background Technology
[0002] With the rapid development of 5G communication technology, the requirements for communication frequency bands are becoming increasingly stringent. Traditional radio frequency filters, limited by their structure and performance, cannot meet the requirements of high-frequency communication. Thin-film bulk acoustic resonators (FBARs), as a novel type of bulk acoustic resonator, have advantages such as small size, light weight, low insertion loss, wide bandwidth, and high quality factor, making them well-suited for the upgrading of wireless communication systems and making FBAR technology one of the research hotspots in the field of communication.
[0003] FBARs require a good seal to prevent corrosion from external environmental factors such as moisture; otherwise, frequency shift and performance degradation may occur. FBARs include a sealing ring structure, which, together with the packaging substrate and the functional substrate (on which the FBAR is mounted), forms a housing space to accommodate the FBAR.
[0004] Furthermore, when the packaging substrate and the functional substrate are facing each other, a metal bonding layer is generally used. The metal bonding layer is located inside the sealing ring in the horizontal direction.
[0005] Figure 1 The diagram shows the existing FBAR packaging structure, in which 101 is the functional substrate, 102 is the sealing ring, 103 is the packaging substrate, 104 is the conductive via, 105 is the metal bonding layer, 106 is the passivation layer, 107 is the top electrode, 108 is the piezoelectric layer, 109 is the acoustic mirror cavity, 110 is the bottom electrode, 111 is the etch barrier layer, and 112 is the release hole.
[0006] To form the acoustic mirror cavity 109 of the FBAR, the sacrificial layer within the cavity needs to be released. Figure 1 In the structure shown, the release process needs to be performed before the bonding process that forms the metal bonding layer. Therefore, to prevent the passivation layer 106 and other exposed film layers from reacting with the release solution, the passivation layer 106 and other exposed film layers need to be made of materials that cannot react with the release solution. This affects both the selection of the release solution and the selection of the materials for the FBAR film layers.
[0007] In addition, such as Figure 1 As shown, with the release hole 112 provided, the horizontal distance between the non-electrode connection end of the top electrode 107 and the sealing ring 102 is I. Because of the release hole 112, this results in a relatively large distance I, leading to a larger area of the FBAR device, which is detrimental to the miniaturization of the FBAR. Summary of the Invention
[0008] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.
[0009] According to one aspect of an embodiment of the present invention, a packaging structure for a bulk acoustic resonator is provided, comprising:
[0010] The encapsulation substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate;
[0011] A functional substrate has a second defining surface, with the first defining surface and the second defining surface facing each other, and a bulk acoustic resonator disposed on the second defining surface;
[0012] A support layer is disposed between and in contact with both the first and second defining surfaces, and the support layer is horizontally disposed outside the effective region of the resonator.
[0013] in:
[0014] The functional substrate has an acoustic mirror cavity for a bulk acoustic resonator on its second defining surface.
[0015] The encapsulation structure includes a release hole that passes through the encapsulation substrate and the support layer and communicates with the acoustic mirror cavity, and the portion of the release hole that passes through the support layer is completely within the support layer.
[0016] Embodiments of the present invention also relate to a packaging structure for a bulk acoustic resonator, comprising:
[0017] The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate;
[0018] A functional substrate having a second defining surface, the surface of the first defining surface and the second defining surface being opposite each other, and the second defining surface being provided with a first bulk acoustic resonator and a second bulk acoustic resonator spaced apart in the horizontal direction.
[0019] A first sealing ring is disposed between a first limiting surface and a second limiting surface and is in contact with both the first and second limiting surfaces. The first sealing ring is disposed around the effective area of the first bulk acoustic resonator. The first limiting surface, the second limiting surface, and the first sealing ring define a first accommodating space. The first bulk acoustic resonator is located within the first accommodating space.
[0020] A second sealing ring is disposed between and in contact with both the first and second limiting surfaces. The second sealing ring surrounds the effective area of the second bulk acoustic resonator. The first limiting surface, the second limiting surface, and the second sealing ring define a second receiving space, within which the second bulk acoustic resonator is located.
[0021] in:
[0022] The first and second body acoustic resonators share an acoustic mirror cavity located on the second defining surface of the functional substrate.
[0023] A gap is provided between the horizontally opposite surfaces of the first sealing ring and the second sealing ring;
[0024] The encapsulation substrate has a through hole in the area corresponding to the gap. The through hole communicates with the gap on the upper side of the gap, and the gap communicates with the acoustic mirror cavity on the lower side of the gap.
[0025] Embodiments of the present invention also relate to a sealing method for a bulk acoustic resonator, comprising the steps of:
[0026] A packaging substrate, a functional substrate, and a support layer are provided. The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate. The functional substrate has a second defining surface. A bulk acoustic wave resonator is adapted to be disposed on the second defining surface of the second substrate. The surface of the first defining surface and the second defining surface are opposite to each other. The support layer is disposed between the first defining surface and the second defining surface and is in contact with both the first defining surface and the second defining surface. The support layer is disposed in the horizontal direction outside the effective region of the resonator. The acoustic mirror of the bulk acoustic wave resonator is an acoustic mirror cavity disposed on the second defining surface, and a sacrificial layer is disposed inside the acoustic mirror cavity.
[0027] A release hole is formed in the thickness direction of the packaging substrate, penetrating the packaging substrate and the support layer; and
[0028] The sacrificial layer within the acoustic mirror cavity is released via the release port to form the acoustic mirror cavity.
[0029] Embodiments of the present invention also relate to a bulk acoustic resonator device, including the above-described packaging structure.
[0030] Embodiments of the present invention also relate to a filter, including the above-described packaging structure or bulk acoustic resonator device.
[0031] Embodiments of the present invention also relate to an electronic device, including the filter described above or the packaging structure described above or a bulk acoustic resonator device. Attached Figure Description
[0032] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:
[0033] Figure 1 This is a schematic diagram of the FBAR packaging structure in the prior art;
[0034] Figure 2A and 2B A cross-sectional schematic diagram of the FBAR packaging structure according to an exemplary embodiment of the present invention;
[0035] Figure 3A and 3B This is a cross-sectional schematic diagram of the FBAR packaging structure according to another exemplary embodiment of the present invention;
[0036] Figure 4A This is a cross-sectional schematic diagram of the FBAR packaging structure according to another exemplary embodiment of the present invention. Figure 4B This is a top view of the FBAR packaging structure according to another exemplary embodiment of the present invention, wherein... Figure 4A for Figure 4B Cross-sectional view of line AA;
[0037] Figure 5A-5M An illustration of an exemplary embodiment of the present invention Figure 3B A schematic diagram illustrating the fabrication process of the packaging structure shown. Detailed Implementation
[0038] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.
[0039] First, the reference numerals in the accompanying drawings of this invention are explained as follows:
[0040] 101: Functional substrate, the optional material being single-crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc. In this embodiment, a bulk acoustic resonator is provided.
[0041] 102: Sealing ring or sealing ring, with optional materials such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, and copper.
[0042] 103: Packaging substrate, with optional materials including single-crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
[0043] 104: Conductive via, filled with metal. The filling metal can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite or alloy of the above metals.
[0044] 105: Bonding metal layer, the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.
[0045] 106: Passivation layer, generally a dielectric material, such as silicon dioxide, aluminum nitride, silicon nitride, etc.
[0046] 107: Top electrode. Materials can include molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or composites or alloys of these metals. The top and bottom electrodes are generally made of the same material, but they can also be different.
[0047] 108: The piezoelectric layer can be a single-crystal piezoelectric material, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate (PZT), single-crystal potassium niobate, single-crystal quartz film, or single-crystal lithium tantalate, etc. It can also be a polycrystalline piezoelectric material (as opposed to single-crystal, a non-single-crystal material), such as polycrystalline aluminum nitride, zinc oxide, PZT, etc. It can also be a rare earth element doped with a certain atomic ratio of the above materials. Mixed materials, such as doped aluminum nitride, contain at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.
[0048] 109: Acoustic mirror cavity, located inside the functional substrate.
[0049] 110: Etching barrier layer, which can be aluminum nitride, silicon nitride, etc.
[0050] 111: Bottom electrode, materials can be selected from: molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or their alloys, etc.
[0051] 112: Release hole, used for etching the sacrificial layer to form the acoustic mirror cavity, in Figure 2B In the middle, the release hole passes through the sealing ring, in Figure 3B In the middle, the release hole passes through the metal bonding layer.
[0052] 113: Pads or electrode leads, the material includes but is not limited to the metal filler, and the material may also be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or their alloys, etc.
[0053] 114: Photoresist.
[0054] 115: Isolation layer, which can be resin, etc.
[0055] 116: Sacrificial layer. The material forming the sacrificial layer can be silicon dioxide, doped silicon dioxide, etc.
[0056] Figure 2A and 2B This is a cross-sectional schematic diagram of the FBAR packaging structure according to an exemplary embodiment of the present invention. Figure 2A and 2B In the embodiment, a receiving space is provided between the packaging substrate 103 and the functional substrate 101, and the FBAR is disposed in the receiving space.
[0057] like Figure 2A and 2B As shown, the release hole 112 passes through the encapsulation substrate 103 and the sealing ring 102, and communicates with the acoustic mirror cavity 109. It can be used in... Figure 2A Perform the process step of releasing the sacrificial layer in cavity 109 in the state shown, and then as follows: Figure 2B As shown, an isolation layer 115 is provided to cover the upper surface of the encapsulation substrate 103 and the opening of the release hole 112 to prevent moisture and other substances from entering the containment space.
[0058] If understood, the bonding metal layer 105 can be electrically connected to the top or bottom electrode of the resonator. If understood, the etch barrier layer 110 may be omitted. If understood, the passivation layer 106 may be omitted.
[0059] exist Figure 2A and 2B In the structure shown, the sealing ring 102 is connected between the lower surface of the encapsulation substrate 103 and the upper surface of the functional substrate 101 and passes through the piezoelectric layer 108. The portion of the release hole 112 that passes through the sealing ring 102 is disposed in the sealing ring 102. The sealing ring 102 can be directly connected to the substrates 101 and 103 or indirectly connected.
[0060] exist Figure 2B In this invention, the release hole 112 does not have a conductive metal layer like the conductive through hole 104. However, the invention is not limited to this. The release hole 112 may also have a conductive metal layer, which may be formed together with the conductive metal in the conductive through hole 104.
[0061] based on Figure 2A-2BThe structure shown in the figure has a release hole 112 that passes through the sealing ring 102 and is located in the sealing ring 102. When the release agent is introduced through the release hole 112, the release agent will not enter the containment space. Therefore, the selection of the materials of the FBAR film layer, such as the passivation layer and the top electrode, can be unaffected by the release agent.
[0062] In addition, based on Figure 2A and 2B The structure can be implemented after the packaging substrate and the functional substrate are bonded together.
[0063] In addition, Figure 2A In China, due to Figure 1 The release hole 112 shown is removed, and the horizontal distance II between the sealing ring 102 and the non-electrode connection end of the top electrode 107 will be less than [a certain value]. Figure 1 The distance I shown is used. Therefore, the area of the entire FBAR device is relative to... Figure 1 The structure shown can be reduced in size.
[0064] exist Figure 2A-2B In this invention, the release hole passes through the sealing ring, but the invention is not limited thereto; the release hole may also pass through the bonded metal layer. Figure 3A and 3B This is a cross-sectional schematic diagram of the FBAR packaging structure according to another exemplary embodiment of the present invention.
[0065] exist Figure 3A and 3B In this process, the metal bonding layer 105 is connected to the substrates 101 and 103. This connection can be direct or indirect.
[0066] like Figure 3A and 3B As shown, the release hole 112 passes through the encapsulation substrate 103, the bonding metal layer 105, and the piezoelectric layer 108 to communicate with the acoustic mirror cavity 109. Other structures are similar to... Figure 2A and 2B The structures shown are basically the same. Based on Figure 2A and 2B The descriptions and explanations provided can also be applied to Figure 3A and 3B The structure shown.
[0067] exist Figure 3A and 3B In the structure shown, the release hole 112 is also a conductive through hole 104.
[0068] exist Figure 3A In China, due to Figure 1 The release hole 112 shown is removed, and the horizontal distance II between the sealing ring 102 and the non-electrode connection end of the top electrode 107 will be less than [a certain value]. Figure 1 The distance I shown is used. Therefore, the area of the entire FBAR device is relative to... Figure 1 The structure shown can be reduced in size.
[0069] The following is a reference to the appendix. Figure 5A-5M Exemplary Description Figure 3B The fabrication process of the structure shown.
[0070] like Figure 5A As shown, the resonator's film structure is fabricated on substrate 101 using conventional FBAR fabrication techniques. Figure 5A In this structure, an acoustic mirror cavity is provided on the upper surface of the substrate 101, which is filled with a sacrificial layer 116. Figure 5A In the middle, an etching barrier layer 110 is also provided below the bottom electrode 111. For example... Figure 5A As shown, the piezoelectric layer 108 has a notch 108A for a sealing ring and a notch 108B for a metal bonding layer 105, and the etching barrier layer 110 has a notch 110A. Figure 5A As shown, notches 108B and 110A are both located within the acoustic mirror cavity. However, as those skilled in the art will understand, if the substrate 101 has a dedicated channel communicating with the acoustic mirror cavity, notches 108B and 110A can also be located at that dedicated channel.
[0071] like Figure 5B-5E As shown, a portion of a metal bonding layer with through-holes (corresponding to a portion of the release hole 112) is formed on the substrate 101 using a lift-off process, and a portion of a sealing ring 102 is also formed on the substrate 101. In this embodiment, the sealing ring is also a metal ring, and like the metal bonding layer, it is bonded together when the substrates 101 and 103 are facing each other. Specifically:
[0072] like Figure 5B As shown, in Figure 5A Photoresist 114 is deposited on the structure shown.
[0073] like Figure 5C As shown, the photoresist 114 is patterned using a photolithography process to form a pattern (i.e., a recess to be filled) corresponding to the sealing ring 102 and the bonding layer 105.
[0074] like Figure 5D As shown, sputtering process is used in Figure 5C A sealing ring and bonding metal are grown within the formed filling recess.
[0075] After that, remove Figure 5D The photoresist 114 in the middle is used to form Figure 5E The structure shown. In Figure 5EIn the middle, a release hole 112 is provided in the bonding metal layer 105 on the substrate 101 side, and the release hole is aligned with the notch 110A. Figure 5E In this process, a sealing ring 102 is formed on the side of the base 101.
[0076] Next, a substrate 103 is provided, on one side of which a bonding metal layer and a sealing ring are formed. A hole is formed in the bonding metal layer, extending from one side of the substrate 103 into the substrate 103. Then, the substrate 103 is thinned from the other side to make the hole a through-hole. Figure 5F As shown, the via is indicated by 104, which passes through the substrate 103 and the metal bonding layer disposed on the substrate 103.
[0077] like Figure 5F As shown, substrate 103 and substrate 101 are bonded together opposite to each other, thereby bonding the metal bonding layers on substrate 103 to the metal bonding layers on substrate 101. The sealing rings on substrate 103 and substrate 101 are also bonded together. In this bonding connection, the through-hole 304 and the release hole 112 are aligned with each other, as shown. Figure 5F As shown.
[0078] like Figure 5G-5K As shown, electrode leads or pads 113 are grown using processes such as sputtering and electroplating. Specifically:
[0079] like Figure 5G As shown, a metal layer (corresponding to the metal layer of 113) is covered on the upper surface of the substrate 103 by sputtering and electroplating processes, and the inner walls of the through hole 104 and the release hole 112 are covered with a metal layer. Finally, the through hole 104 and the release hole 112 are holes defined by, for example, electroplated metal layers, with the upper end of the hole opening on the upper surface of the substrate 103 and the lower end opening on the sacrificial layer 116.
[0080] like Figure 5H As shown, in Figure 5G Photoresist 114 is coated on the structure.
[0081] Next, the photoresist 114 is patterned to form Figure 5I The structure is then formed by removing the metal layer outside the photoresist 114 to create a structure like... Figure 5J The structure shown.
[0082] like Figure 5K As shown, photoresist 114 is removed to form pads or electrode leads 113.
[0083] like Figure 5L As shown, via Figure 5KA release agent is introduced into the release hole formed by the conductive through hole 104 and the release hole 112 to release the sacrificial layer 116 in the acoustic mirror cavity and form the acoustic mirror cavity 109.
[0084] like Figure 5M As shown, in Figure 5L In the structure shown, an isolation layer 315 is provided to prevent moisture and other substances from entering the release hole. The isolation layer may only cover the opening of the release hole or it may cover the entire upper surface of the substrate 103, both of which are within the protection scope of this invention.
[0085] The above examples illustrate Figure 3B The manufacturing process of the aforementioned structure, for Figure 2B The structure shown is manufactured in a similar process to that described above. However, adjustments are required. Figures 5A-5E The process shown allows for the formation of a structure similar to the one shown within the notch 108A. Figure 5E The structure in the notch 108B of the substrate 103 has a through hole provided in the sealing ring when providing the sealing ring of the substrate 103.
[0086] In this invention, a release hole is used in the support layer (which may be a sealing ring or a metal bonding layer) between the packaging substrate and the functional substrate and communicates with the acoustic mirror cavity to perform the release process. This eliminates the need for a separate release hole that is specially provided in the prior art, thereby reducing the area of the bulk acoustic wave resonator device and avoiding contact between the release agent and some film layers of the resonator during the release process.
[0087] Figure 4A This is a cross-sectional schematic diagram of the FBAR packaging structure according to another exemplary embodiment of the present invention. Figure 4B This is a top view of the FBAR packaging structure according to another exemplary embodiment of the present invention, wherein... Figure 4A for Figure 4B Cross-sectional view of line AA in the middle.
[0088] like Figure 4A and 4B As shown, two bulk acoustic wave resonators are arranged adjacent to each other and share an acoustic mirror cavity 109. A gap S exists between the sealing rings 102 of the two adjacent resonators. The upper end of the gap S has a through-hole 103A penetrating the substrate 103, and the lower end of the gap has a through-hole 112 (i.e., a release hole 112) penetrating the piezoelectric layer 108. Thus, the release agent can enter the acoustic mirror cavity 109 through the through-hole 103A, the gap S, and the through-hole 112 to release the sacrificial layer within it. This method also eliminates the need for a dedicated release hole within the receiving space found in conventional bulk acoustic wave resonators and avoids contact between the release agent and the corresponding film layer of the bulk acoustic wave resonator.
[0089] exist Figures 4A-4BIn the illustrated embodiment, a through-hole 112 penetrating the piezoelectric layer 108 is provided at the lower end of the gap, but the present invention is not limited thereto. In the absence of a piezoelectric layer at the gap, the gap may also communicate with the acoustic mirror cavity via a dedicated channel or through-hole. These are all within the scope of protection of the present invention.
[0090] In the present invention Figures 2A-3B In the illustrated embodiment, the support layer or sealing ring penetrates the piezoelectric layer to connect with the functional substrate, but the invention is not limited thereto. In cases where no piezoelectric layer is provided outside the effective region of the resonator, or only a piezoelectric layer with a small extension width is provided, the support layer or sealing ring can also be directly connected to the functional substrate. Whether or not the support layer or sealing ring penetrates the piezoelectric layer, both are within the scope of protection of this invention.
[0091] In this invention, "upper" and "lower" refer to the bottom surface of the functional base of the packaging structure. For a component, the side closer to the bottom surface is the lower side, and the side farther from the bottom surface is the upper side.
[0092] In this invention, "inner" and "outer" are relative to the bulk acoustic wave resonator located within the accommodating space in the lateral or radial direction. The side or end of a component closer to the bulk acoustic wave resonator is called the inner side or inner end, while the side or end of the component farther from the bulk acoustic wave resonator is called the outer side or outer end. For a reference position, being inside the position indicates being between that position and the bulk acoustic wave resonator in the lateral or radial direction, while being outside the position indicates being farther from the bulk acoustic wave resonator in the lateral or radial direction than that position.
[0093] As will be understood by those skilled in the art, bulk acoustic resonators can be used to form filters or other semiconductor devices.
[0094] Based on the above, the present invention proposes the following technical solution:
[0095] 1. A packaging structure for a bulk acoustic wave resonator, comprising:
[0096] The encapsulation substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate;
[0097] A functional substrate has a second defining surface, with the first defining surface and the second defining surface facing each other, and a bulk acoustic resonator disposed on the second defining surface;
[0098] A support layer is disposed between and in contact with both the first and second defining surfaces, and the support layer is horizontally disposed outside the effective region of the resonator.
[0099] in:
[0100] The functional substrate has an acoustic mirror cavity for a bulk acoustic resonator on its second defining surface.
[0101] The encapsulation structure includes a release hole that passes through the encapsulation substrate and the support layer and communicates with the acoustic mirror cavity, and the portion of the release hole that passes through the support layer is completely within the support layer.
[0102] 2. The packaging structure according to claim 1, wherein:
[0103] The support layer is a metal bonding layer, and the metal bonding layer is electrically connected to the top electrode or bottom electrode of the resonator.
[0104] 3. The packaging structure according to claim 2, wherein:
[0105] The release hole is a conductive release hole, which includes a channel passing through it and communicating with the cavity of the acoustic mirror.
[0106] 4. The packaging structure according to claim 1, wherein:
[0107] The support layer is a sealing ring, and the first limiting surface, the second limiting surface and the sealing ring define an accommodating space, in which the bulk acoustic resonator is located.
[0108] 5. The packaging structure according to claim 4, wherein:
[0109] The packaging structure includes a bonding metal layer disposed between the first defining surface and the second defining surface;
[0110] The sealing ring is located on the outside of the bonded metal layer in the horizontal direction.
[0111] 6. The packaging structure according to claim 4, wherein:
[0112] The release hole is a conductive release hole, and the conductive release hole defines a channel communicating with the cavity of the acoustic mirror.
[0113] 7. The packaging structure according to any one of claims 1-6, wherein:
[0114] The encapsulation structure further includes an isolation layer that covers the first non-limited surface and the opening of the release hole on the first non-limited surface.
[0115] 8. A packaging structure for a bulk acoustic wave resonator, comprising:
[0116] The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate;
[0117] A functional substrate having a second defining surface, the surface of the first defining surface and the second defining surface being opposite each other, and the second defining surface being provided with a first bulk acoustic resonator and a second bulk acoustic resonator spaced apart in the horizontal direction.
[0118] A first sealing ring is disposed between a first limiting surface and a second limiting surface and is in contact with both the first and second limiting surfaces. The first sealing ring is disposed around the effective area of the first bulk acoustic resonator. The first limiting surface, the second limiting surface, and the first sealing ring define a first accommodating space. The first bulk acoustic resonator is located within the first accommodating space.
[0119] A second sealing ring is disposed between and in contact with both the first and second limiting surfaces. The second sealing ring surrounds the effective area of the second bulk acoustic resonator. The first limiting surface, the second limiting surface, and the second sealing ring define a second receiving space, within which the second bulk acoustic resonator is located.
[0120] in:
[0121] The first and second body acoustic resonators share an acoustic mirror cavity located on the second defining surface of the functional substrate.
[0122] A gap is provided between the horizontally opposite surfaces of the first sealing ring and the second sealing ring;
[0123] The encapsulation substrate has a through hole in the area corresponding to the gap. The through hole communicates with the gap on the encapsulation substrate side of the gap, and the gap communicates with the acoustic mirror cavity on the functional substrate side of the gap.
[0124] 9. The packaging structure according to claim 8, wherein:
[0125] The packaging structure further includes an isolation layer that covers the first non-limited surface and the opening of the first through-hole on the first non-limited surface.
[0126] 10. A method for packaging a bulk acoustic resonator, comprising the following steps:
[0127] A packaging substrate, a functional substrate, and a support layer are provided. The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate. The functional substrate has a second defining surface. A bulk acoustic wave resonator is adapted to be disposed on the second defining surface of the second substrate. The surface of the first defining surface and the second defining surface are opposite to each other. The support layer is disposed between the first defining surface and the second defining surface and is in contact with both the first defining surface and the second defining surface. The support layer is disposed in the horizontal direction outside the effective region of the resonator. The acoustic mirror of the bulk acoustic wave resonator is an acoustic mirror cavity disposed on the second defining surface, and a sacrificial layer is disposed inside the acoustic mirror cavity.
[0128] A release hole is formed in the thickness direction of the packaging substrate, penetrating the packaging substrate and the support layer; and
[0129] The sacrificial layer within the acoustic mirror cavity is released via the release port to form the acoustic mirror cavity.
[0130] 11. The method according to claim 10, wherein:
[0131] The support layer is a bonded metal layer or a sealing ring.
[0132] 12. The method according to claim 11, wherein:
[0133] The step of forming a release hole penetrating the package substrate and the support layer in the thickness direction of the package substrate includes: forming a through hole penetrating the package substrate and the support layer in the thickness direction of the package substrate; and forming a metal wall on the inner wall of the through hole using an electroplating process, the metal wall defining the release hole.
[0134] 13. The method according to any one of claims 10-12, wherein:
[0135] The release hole opens onto the first non-limited surface; and
[0136] The method further includes the step of: providing an isolation layer on a first non-limited surface, the isolation layer covering the first non-limited surface and covering the opening of the release hole on the first non-limited surface.
[0137] 13. A bulk acoustic resonator device, comprising the packaging structure according to any one of claims 1-9.
[0138] 14. A filter comprising the packaging structure according to any one of claims 1-9 or the bulk acoustic resonator device according to claim 13.
[0139] 15. An electronic device comprising a packaging structure according to any one of claims 1-9, a bulk acoustic resonator device according to claim 13, or a filter according to claim 14.
[0140] The electronic devices mentioned here include, but are not limited to, intermediate products such as radio frequency front-ends and filtering and amplification modules, as well as terminal products such as mobile phones, WIFI, and drones.
[0141] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A packaging structure for a bulk acoustic wave resonator, comprising: The encapsulation substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate; A functional substrate has a second defining surface, with the first defining surface and the second defining surface facing each other, and a bulk acoustic resonator disposed on the second defining surface; A support layer is disposed between the first limiting surface and the second limiting surface and is in contact with both the first limiting surface and the second limiting surface. The support layer is positioned horizontally outside the effective region of the resonator. in: The functional substrate has an acoustic mirror cavity for a bulk acoustic resonator on its second defining surface. At least a portion of the support layer is located within the boundary of the acoustic mirror cavity, and the encapsulation structure includes a release hole that passes through the encapsulation substrate and the support layer and communicates with the acoustic mirror cavity, with the portion of the release hole passing through the support layer completely within the support layer.
2. The packaging structure according to claim 1, wherein: The support layer is a metal bonding layer, and the metal bonding layer is electrically connected to the top electrode or bottom electrode of the resonator.
3. The packaging structure according to claim 2, wherein: The release hole is a conductive release hole, which includes a channel passing through it and communicating with the cavity of the acoustic mirror.
4. The packaging structure according to claim 1, wherein: The support layer is a sealing ring, and the first limiting surface, the second limiting surface and the sealing ring define an accommodating space, in which the bulk acoustic resonator is located.
5. The packaging structure according to claim 4, wherein: The packaging structure includes a bonding metal layer disposed between the first defining surface and the second defining surface; The sealing ring is located on the outside of the bonded metal layer in the horizontal direction.
6. The packaging structure according to claim 4, wherein: The release hole is a conductive release hole, and the conductive release hole defines a channel communicating with the cavity of the acoustic mirror.
7. The packaging structure according to any one of claims 1-6, wherein: The encapsulation structure further includes an isolation layer that covers the first non-limited surface and the opening of the release hole on the first non-limited surface.
8. A packaging structure for a bulk acoustic resonator, comprising: The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate; A functional substrate having a second defining surface, the surface of the first defining surface and the second defining surface being opposite each other, and the second defining surface being provided with a first bulk acoustic resonator and a second bulk acoustic resonator spaced apart in the horizontal direction. A first sealing ring is disposed between a first limiting surface and a second limiting surface and is in contact with both the first and second limiting surfaces. The first sealing ring is disposed around the effective area of the first bulk acoustic resonator. The first limiting surface, the second limiting surface, and the first sealing ring define a first accommodating space. The first bulk acoustic resonator is located within the first accommodating space. A second sealing ring is disposed between and in contact with both the first and second limiting surfaces. The second sealing ring surrounds the effective area of the second bulk acoustic resonator. The first limiting surface, the second limiting surface, and the second sealing ring define a second receiving space, within which the second bulk acoustic resonator is located. in: The first and second body acoustic resonators share an acoustic mirror cavity located on the second defining surface of the functional substrate. A gap is provided between the horizontally opposite surfaces of the first sealing ring and the second sealing ring; The encapsulation substrate has a through hole in the area corresponding to the gap. The through hole communicates with the gap on the encapsulation substrate side of the gap and with the acoustic mirror cavity on the functional substrate side of the gap.
9. The packaging structure according to claim 8, wherein: The packaging structure further includes an isolation layer that covers the first non-limited surface and the opening of the first through-hole on the first non-limited surface.
10. A method for packaging a bulk acoustic resonator, comprising the following steps: A packaging substrate, a functional substrate, and a support layer are provided. The packaging substrate has a first defining surface and a first non-defining surface opposite to the first defining surface in the thickness direction of the substrate. The functional substrate has a second defining surface. A bulk acoustic wave resonator is adapted to be disposed on the second defining surface of the second substrate. The surfaces of the first defining surface and the second defining surface are opposite to each other. The support layer is disposed between the first defining surface and the second defining surface and is in contact with both the first defining surface and the second defining surface. The support layer is disposed horizontally outside the effective region of the resonator. The acoustic mirror of the bulk acoustic resonator is an acoustic mirror cavity disposed on the second defining surface, at least part of the support layer is located within the boundary range of the acoustic mirror cavity, and a sacrificial layer is disposed inside the acoustic mirror cavity; A release hole is formed that penetrates the packaging substrate and the support layer in the thickness direction of the packaging substrate; as well as The sacrificial layer within the acoustic mirror cavity is released via the release port to form the acoustic mirror cavity.
11. The method of claim 10, wherein: The support layer is a bonded metal layer or a sealing ring.
12. The method according to claim 11, wherein: The step of forming a release hole penetrating the package substrate and the support layer in the thickness direction of the package substrate includes: forming a through hole penetrating the package substrate and the support layer in the thickness direction of the package substrate; and forming a metal wall on the inner wall of the through hole using an electroplating process, the metal wall defining the release hole.
13. The method according to any one of claims 10-12, wherein: The release hole opens onto the first non-limited surface; and The method further includes the step of: providing an isolation layer on a first non-limited surface, the isolation layer covering the first non-limited surface and covering the opening of the release hole on the first non-limited surface.
14. A bulk acoustic resonator device, comprising the packaging structure according to any one of claims 1-9.
15. A filter comprising the packaging structure according to any one of claims 1-9 or the bulk acoustic resonator device according to claim 13.
16. An electronic device comprising a packaging structure according to any one of claims 1-9, a bulk acoustic resonator device according to claim 13, or a filter according to claim 14.