Method of manufacturing a filter, filter and diplexer

Abstract

The embodiment of the present application discloses a filter preparation method, a filter and a duplexer. At least one resonator layer is formed on one side of a first protective substrate and / or one side of a second protective substrate, so that at least two resonator layers arranged along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate. The thicknesses of corresponding set film layers in the at least two resonator layers are different, and the set film layers are at least one of a lower electrode layer, an upper electrode layer and a piezoelectric layer. According to the technical scheme, the thickness of the mass load layer can be controlled by controlling the thickness of the set film layer deposited by different resonator layers, and the thickness of the mass load layer can be measured by calculating the thickness difference of the set film layer of different resonator layers, so that the thickness of the mass load layer can be accurately controlled and measured, the resonator layer can be accurately tuned, and the frequency of the filter can be accurately controlled.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and more particularly to a method for fabricating a filter, a filter, and a duplexer. Background Technology

[0002] With the development of communication technology, the requirements for the frequency accuracy of filters are becoming increasingly higher.

[0003] In filters, the thickness of the mass loading layer affects the filter's frequency. In existing technologies, filters typically include a substrate and a single-layer resonator layer disposed on one side of the substrate. The resonator layer includes a stacked lower electrode layer, a piezoelectric layer, and a top electrode layer. This single-layer resonator layer typically includes multiple resonators, among which are resonators with upper electrodes (located in the upper electrode layer) of different thicknesses. In the resonators with different upper electrode thicknesses, the portion of the upper electrode thicker than that of the resonator with the thinner upper electrode serves as the mass loading layer for the resonator with the thicker upper electrode. Because the thickness of the upper electrode may differ for different resonators, the fabrication of the upper electrode layer requires multiple depositions of the upper electrode material to achieve different thicknesses for the upper electrodes corresponding to different resonators; alternatively, a single deposition followed by multiple etching processes can be used to achieve the same result.

[0004] The above preparation methods are complex, and in the filter structure obtained by the above preparation methods, the mass load layer is connected to the upper electrode layer, making it difficult to accurately measure and control the actual thickness of the mass load layer, which causes difficulties in controlling the filter frequency. Summary of the Invention

[0005] This invention provides a method for fabricating a filter, a filter, and a duplexer to achieve accurate control and measurement of the thickness of the mass load layer, thereby improving the accuracy of the filter.

[0006] In a first aspect, embodiments of the present invention provide a method for fabricating a filter, comprising:

[0007] Provide a first protective substrate and a second protective substrate;

[0008] At least one resonator layer is formed on one side of the first protective substrate and / or on one side of the second protective substrate;

[0009] A first protective substrate and a second protective substrate are connected in the thickness direction of the filter, so that at least two resonator layers are formed between the first protective substrate and the second protective substrate along the thickness direction of the filter.

[0010] The resonator layer includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer stacked together. The thickness of corresponding set film layers in at least two resonator layers is different, and the set film layer is at least one of the lower electrode layer, the upper electrode layer, and the piezoelectric layer.

[0011] Optionally, before connecting the first protective substrate and the second protective substrate in the filter thickness direction to form at least two resonator layers disposed along the filter thickness direction between the first protective substrate and the second protective substrate, the method further includes:

[0012] An intermediate substrate is provided, and at least one resonator layer is formed on a first side and / or a second side of the intermediate substrate; wherein the first side and the second side of the intermediate substrate are opposite sides of the intermediate substrate;

[0013] A first protective substrate and a second protective substrate are connected in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, including:

[0014] The first protective substrate and the intermediate substrate are bonded together on the first side of the intermediate substrate using a bonding structure;

[0015] The second protective substrate is bonded to the intermediate substrate on the second side of the intermediate substrate using a bonding structure.

[0016] Optionally, the first protective substrate and the intermediate substrate are bonded on a first side of the intermediate substrate using a bonding structure, including:

[0017] At least one of the surface of the first protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first protective substrate, is bonded to at least one of the surface of the intermediate substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first side of the intermediate substrate.

[0018] The second protective substrate and the intermediate substrate are bonded together on the second side of the intermediate substrate using a bonding structure, including:

[0019] At least one of the surface of the second protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate, is bonded to at least one of the surface of the intermediate substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second side of the intermediate substrate.

[0020] Optionally, a resonator layer is formed on one side of the first protective substrate and / or one side of the second protective substrate, including:

[0021] At least one resonator layer is formed on one side of the second protective substrate;

[0022] At least two resonator layers are formed layer by layer on one side of the first protective substrate;

[0023] A first protective substrate and a second protective substrate are connected in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, including:

[0024] The side of the second protective substrate with the resonator layer and the side of the first protective substrate with the resonator layer are bonded together by a bonding structure.

[0025] Optionally, at least two resonator layers are formed layer by layer on one side of the first protective substrate, including: forming a first resonator layer on one side of the first protective substrate; and forming a second resonator layer adjacent to the first resonator layer on the side of the first resonator layer away from the first protective substrate.

[0026] After forming a first resonator layer on one side of the first protective substrate, a second resonator layer adjacent to the first resonator layer is formed on the side of the first resonator layer away from the first protective substrate, including: forming a capping layer on the side of the first resonator layer away from the first protective substrate, and forming a second resonator layer on the side of the capping layer away from the first protective substrate.

[0027] Optionally, the side of the second protective substrate with the resonator layer and the side of the first protective substrate with the resonator layer are bonded together using a bonding structure, including:

[0028] At least one of the surface of the second protective substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate, is bonded to at least one of the surface of the first protective substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the first protective substrate, or the capping layer on one side of the resonator layer.

[0029] Optionally, at least one resonator layer is formed on one side of the first protective substrate and / or one side of the second protective substrate, including:

[0030] An acoustic reflection structure is formed on one side of a substrate, wherein the substrate is a first protective substrate and / or a second protective substrate;

[0031] On the side of the substrate where an acoustic reflection structure is formed, a lower electrode layer, a piezoelectric layer, and an upper electrode layer are formed sequentially.

[0032] Optionally, a lower electrode layer, a piezoelectric layer, and an upper electrode layer are sequentially formed on the side of the substrate where the acoustic reflection structure is formed, including:

[0033] On the side of the substrate where an acoustic reflection structure is formed, a lower electrode layer is formed using a single deposition process and a single patterning process.

[0034] A piezoelectric layer is formed on the side of the lower electrode layer away from the substrate using a single deposition process and a single patterning process;

[0035] An upper electrode layer is formed on the side of the piezoelectric layer away from the designated substrate using a single deposition process and a single patterning process.

[0036] Optionally, before forming a capping layer on the side of the first resonator layer away from the first protective substrate, the method further includes:

[0037] A sacrificial material is formed on the side of the first resonator layer away from the first protective substrate;

[0038] After forming a capping layer on the side of the first resonator layer away from the first protective substrate, the method further includes:

[0039] Release the sacrificial materials.

[0040] Optionally, at least one resonator layer is formed on one side of the first protective substrate and / or one side of the second protective substrate, including:

[0041] At least one resonator layer and at least one capping layer are formed on one side of the first protective substrate;

[0042] At least one resonator layer and at least one capping layer are formed on one side of the second protective substrate;

[0043] A first protective substrate and a second protective substrate are connected in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, including:

[0044] The side of the first protective substrate with the resonator layer and the side of the second protective substrate with the resonator layer are bonded together by a bonding structure.

[0045] Optionally, the side of the first protective substrate with the resonator layer and the side of the second protective substrate with the resonator layer are bonded together using a bonding structure, including:

[0046] At least one of the surface of the first protective substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer, and the capping layer of the resonator layer disposed on the first protective substrate, is bonded to at least one of the surface of the second protective substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer, and the capping layer of the resonator layer disposed on the second protective substrate.

[0047] Secondly, embodiments of the present invention also provide a filter, characterized in that it includes:

[0048] A first protective substrate and a second protective substrate along the thickness direction of the filter, and at least two resonator layers disposed between the first protective substrate and the second protective substrate along the thickness direction of the filter.

[0049] The resonator layer includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer stacked together. The thickness of corresponding design films in at least two resonator layers is different, and the design film is at least one of the lower electrode layer, the upper electrode layer, and the piezoelectric layer.

[0050] Optionally, the resonator layer includes multiple resonators, each including a lower electrode in the lower electrode layer, a piezoelectric unit in the piezoelectric layer, and an upper electrode in the upper electrode layer. The thickness of the same film layer is the same for each resonator in the same resonator layer.

[0051] Optionally, at least some of the adjacent resonator layers are bonded together by a bonding structure.

[0052] Optionally, the filter further includes at least one intermediate substrate disposed between the first protective substrate and the second protective substrate; a resonator layer is disposed on the side of the intermediate substrate close to and / or away from the first protective substrate;

[0053] The first protective substrate is bonded to the adjacent intermediate substrate through a bonding structure, and the second protective substrate is bonded to the adjacent intermediate substrate through a bonding structure.

[0054] Optionally, a capping layer is provided between at least some of the adjacent resonator layers, and the resonator layers on both sides of the capping layer are connected by a connection structure that penetrates the capping layer.

[0055] Optionally, the connection structure is a conductive lead;

[0056] Optionally, the capping layer is formed by deposition.

[0057] Optionally, multiple cavities are formed between the cap layer and the upper electrode layer of the resonator layer on the first side, and an acoustic reflection structure is provided on the second side of the cap layer. The lower electrode layer of the resonator layer on the second side at least partially covers the acoustic reflection structure. The first side and the second side are opposite sides of the cap layer.

[0058] Optionally, the bonding structure is a first sealing ring, which is disposed between adjacent substrates. The substrate is any substrate or capping layer of the filter, and the first sealing ring between adjacent substrates forms a sealing structure.

[0059] Thirdly, embodiments of the present invention also provide a duplexer, including a transmit filter and a receive filter, wherein the transmit filter and / or the receive filter is the filter provided in the second aspect.

[0060] Optionally, the transmit filter and the receive filter are bonded together in the thickness direction of the duplexer.

[0061] Optionally, the duplexer also includes a second sealing ring located between the transmitting filter and the receiving filter, which are bonded together via the second sealing ring.

[0062] The filter fabrication method, filter, and duplexer of this embodiment involve forming at least one resonator layer on one side of a first protective substrate and / or one side of a second protective substrate, and connecting the first and second protective substrates in the filter thickness direction. This results in at least two resonator layers disposed along the filter thickness direction between the first and second protective substrates. The corresponding set film layers in the at least two resonator layers have different thicknesses, and the set film layers are at least one of a lower electrode layer, an upper electrode layer, and a piezoelectric layer. This invention allows for the control of the mass load layer thickness by controlling the thickness of the set film layers deposited in different resonator layers, and the measurement of the mass load layer thickness by calculating the thickness difference from the set film layers of different resonator layers. Therefore, the thickness of the mass load layer can be precisely controlled and measured, which is beneficial for precise frequency tuning of the resonator layer, and consequently, precise control of the filter frequency. Furthermore, the filter fabrication method of this embodiment controls the thickness of the mass load layer by controlling the thickness difference of the set film layers in different resonator layers. Therefore, for the same resonator layer, the thickness of the lower electrode layer can be uniform, the thickness of the piezoelectric layer can be uniform, and the thickness of the upper electrode layer can be uniform. Therefore, when fabricating the resonator layer, it is not necessary to use the existing technology of multiple deposition or multiple etching, thereby simplifying the filter fabrication process. Attached Figure Description

[0063] Figure 1 This is a flowchart of a filter fabrication method provided in an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of the structure after a resonator layer is formed on one side of the first protective substrate, as provided in an embodiment of the present invention.

[0065] Figure 3 This is a schematic diagram of the structure after a resonator layer is formed on one side of the second protective substrate, as provided in an embodiment of the present invention.

[0066] Figure 4 This is a schematic diagram of the filter structure obtained by connecting the first protective substrate and the second protective substrate according to an embodiment of the present invention;

[0067] Figure 5 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention;

[0068] Figure 6 This is a schematic diagram of the structure after the first protective substrate and the first side of the intermediate substrate are bonded together by a bonding structure;

[0069] Figure 7 This is a schematic diagram of the structure after a resonator layer is formed on the second side of the intermediate substrate, as provided in an embodiment of the present invention;

[0070] Figure 8 This is a schematic diagram of the filter structure obtained by bonding the second protective substrate to the second side of the intermediate substrate using a bonding structure.

[0071] Figure 9 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention;

[0072] Figure 10 This is a schematic diagram of the structure after two resonator layers are formed on one side of the first protective substrate;

[0073] Figure 11 This is a schematic diagram of the filter structure obtained by bonding the second protective substrate to the capping layer;

[0074] Figure 12 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention;

[0075] Figure 13 This is a schematic diagram of the filter structure obtained by bonding the film layer furthest from the first protective substrate on one side and the film layer furthest from the second protective substrate on one side using a bonding structure according to an embodiment of the present invention.

[0076] Figure 14 This is a flowchart of forming a resonator layer on one side of a defined substrate, provided by an embodiment of the present invention;

[0077] Figure 15 This is a top view of a filter provided in an embodiment of the present invention;

[0078] Figure 16 This is a schematic diagram of the structure of a duplexer provided in an embodiment of the present invention;

[0079] Figure 17 This is a schematic diagram of another duplexer provided in an embodiment of the present invention. Detailed Implementation

[0080] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0081] This invention provides a method for fabricating a filter. Figure 1 This is a flowchart of a filter fabrication method provided in an embodiment of the present invention, see reference. Figure 1 The method for fabricating this filter includes:

[0082] Step 110: Provide a first protective substrate and a second protective substrate;

[0083] In this embodiment, one of the first protective substrate and the second protective substrate is located at the bottom of the filter, and the other is located at the top of the filter, thereby protecting the resonator layer in the filter. The materials of the first protective substrate and the second protective substrate can be silicon, gallium arsenide, silicon carbide, gallium nitride, or a mixture of at least two of the above materials. This embodiment does not impose a specific limitation.

[0084] Step 120: Form at least one resonator layer on one side of the first protective substrate and / or one side of the second protective substrate;

[0085] In this step, a resonator layer can be formed only on one side of the first protective substrate, or only on one side of the second protective substrate, or both on one side of the first protective substrate and on one side of the second protective substrate. This ensures that after the first and second protective substrates are connected in the filter thickness direction, there are at least two resonator layers disposed in the filter thickness direction between them.

[0086] Figure 2 This is a schematic diagram of the structure after a resonator layer is formed on one side of the first protective substrate, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure after a resonator layer is formed on one side of the second protective substrate, according to an embodiment of the present invention. (Reference) Figure 2 and Figure 3 The resonator layer 220 includes a lower electrode layer 221, a piezoelectric layer 222, and an upper electrode layer 223 stacked together. In the same resonator layer 220 on the first protective substrate 210, the lower electrode layer 221 is located on the side closer to the first protective substrate 210 relative to the upper electrode layer 223; in the same resonator layer 220 on the second protective substrate 230, the lower electrode layer 221 is located on the side closer to the second protective substrate 230, equivalent to the upper electrode layer 223. In each resonator layer 220, the piezoelectric layer 222 is located between the lower electrode layer 221 and the upper electrode layer 223. Optionally, the material of the upper electrode layer 223 and the material of the lower electrode layer 221 can be at least one of metals such as molybdenum, aluminum, and tungsten, or other alloy materials, or non-metallic materials such as doped polycrystalline silicon. Optionally, the deposition material of the piezoelectric layer 222 can be at least one of aluminum nitride, silicon oxide, and piezoelectric ceramics.

[0087] Step 130: Connect the first protective substrate and the second protective substrate in the thickness direction of the filter so that at least two resonator layers are formed between the first protective substrate and the second protective substrate along the thickness direction of the filter.

[0088] Figure 4 This is a schematic diagram of the filter structure obtained by connecting the first protective substrate and the second protective substrate according to an embodiment of the present invention. (Reference) Figure 4 Optionally, the connection between the first protective substrate 210 and the second protective substrate 230 is made indirectly through the bonding structure 240. Figure 4 The example shown only includes one resonator layer on one side of the first protective substrate 210 and one resonator layer on one side of the second protective substrate 230. The first protective substrate 210 or the second protective substrate 230 may also include at least two resonator layers. When at least two resonator layers stacked along the filter thickness direction y1 are provided on the first protective substrate 210, the second protective substrate 230 may or may not have a resonator layer. When at least two resonator layers stacked along the filter thickness direction y1 are provided on the second protective substrate 230, the first protective substrate 210 may or may not have a resonator layer.

[0089] The filter fabricated by the method of this embodiment has each resonator layer 220 arranged along the thickness direction y1 of the filter. Each resonator layer 220 forms a vertical structure rather than a flat structure, which reduces the area of ​​the plane occupied by the filter, improves the integration of the filter, and thus helps to realize the miniaturization of the filter.

[0090] In this embodiment, the thicknesses of corresponding predetermined films in at least two resonator layers 220 are different, and the predetermined films are at least one of the lower electrode layer 221, the upper electrode layer 223, and the piezoelectric layer 222. That is, in this embodiment, the resonator satisfies at least one of the following conditions: 1) the thicknesses of the upper electrode layers 223 in at least two resonator layers 220 are different; 2) the thicknesses of the lower electrode layers 221 in at least two resonator layers 220 are different; 3) the thicknesses of the piezoelectric layers 222 in at least two resonator layers 220 are different. In the two resonator layers 220 with different upper electrode layer 223 thicknesses, the difference in the thickness of the upper electrode layer 223 allows the portion of the upper electrode layer 223 thicker than that of the resonator layer 220 with the thicker upper electrode layer 223 to serve as the mass load layer of the resonator layer 220 with the thicker upper electrode layer 223. Similarly, in the two resonator layers 220 with different lower electrode layer 221 thicknesses, the difference in the thickness of the lower electrode layer 221 allows the portion of the upper electrode layer 223 thicker than that of the resonator layer 220 with the thicker lower electrode layer 223 to serve as the mass load layer of the resonator layer 220 with the thicker lower electrode layer 223. The portion of the resonator layer 220 with a thicker lower electrode layer 221 than the resonator layer 220 with a thinner lower electrode layer 221 can serve as the mass load layer of the resonator layer 220 with a thicker lower electrode layer 221. In two resonator layers 220 with different piezoelectric layer 222 thicknesses, due to the difference in piezoelectric layer 222 thickness, the portion of the resonator layer 220 with a thicker piezoelectric layer 222 than the resonator layer 220 with a thinner piezoelectric layer 222 can serve as the mass load layer of the resonator layer 220 with a thicker piezoelectric layer 222. Wherein, Figure 4 The diagram schematically illustrates the case where the film layer is set as the upper electrode layer 223, i.e. Figure 4 The diagram illustrates a case where the upper electrode layer 223 of the two resonator layers 220 has different thicknesses.

[0091] Compared to the existing technology where only one resonator layer 220 is disposed on the same substrate, and the mass load layer is fabricated by controlling the different thicknesses of the upper electrode of the resonator in the same resonator layer 220, the technical solution of this embodiment can control the thickness of the mass load layer by controlling at least one of the thickness difference of the upper electrode layer 223 in different resonator layers 220, the thickness difference of the lower electrode layer 221 in different resonator layers 220, and the thickness difference of different resonator layers 220. Specifically, the thickness of the mass load layer can be controlled by controlling the thickness of at least one of the upper electrode layer 223, the lower electrode layer 221, and the piezoelectric layer 222 deposited in different resonator layers 220. In this embodiment, by setting different thicknesses of the set film layers (at least one of the upper electrode layer 223, lower electrode layer 221, and piezoelectric layer 222) in at least two resonator layers 220, the thickness of the mass load layer can be controlled by controlling the thickness of the set film layers deposited in different resonator layers 220. Furthermore, the thickness of the mass load layer can be measured by calculating the thickness difference through measuring the thickness of the set film layers in different resonator layers 220. Therefore, the thickness of the mass load layer can be precisely controlled and measured, which is beneficial for precise frequency tuning of the resonator layers 220, and thus for precise control of the filter frequency. Moreover, because the filter fabrication method of this embodiment forms a filter where each resonator layer 220 is arranged in the filter thickness direction y1, each resonator layer can be precisely tuned individually during the layer-by-layer formation process, avoiding mutual interference between different resonators during the tuning process.

[0092] As described above, the filter fabrication method of this embodiment controls the thickness of the mass load layer by controlling the thickness difference of the set film layers in different resonator layers 220. Therefore, for the same resonator layer 220, the thickness of the lower electrode layer 221 can be uniform, the thickness of the piezoelectric layer 222 can be uniform, and the thickness of the upper electrode layer 223 can be uniform. Therefore, when fabricating the resonator layer 220, it is not necessary to use the existing technology of multiple deposition or multiple etching, thereby simplifying the filter fabrication process.

[0093] The filter fabrication method of this embodiment involves forming at least one resonator layer on one side of a first protective substrate and / or one side of a second protective substrate, and connecting the first and second protective substrates in the filter thickness direction. This results in at least two resonator layers disposed along the filter thickness direction between the first and second protective substrates. The corresponding design films in the at least two resonator layers have different thicknesses, and the design film is at least one of a lower electrode layer, an upper electrode layer, and a piezoelectric layer. This embodiment allows for control of the mass load layer thickness by controlling the thickness of the design films deposited in different resonator layers, and the thickness of the mass load layer can be measured by calculating the thickness difference through measuring the thickness of the design films in different resonator layers. Therefore, the thickness of the mass load layer can be precisely controlled and measured, which is beneficial for precise frequency tuning of the resonator layer, and consequently, precise control of the filter frequency. Furthermore, the filter fabrication method of this embodiment controls the thickness of the mass load layer by controlling the thickness difference of the set film layers in different resonator layers. Therefore, for the same resonator layer, the thickness of the lower electrode layer can be uniform, the thickness of the piezoelectric layer can be uniform, and the thickness of the upper electrode layer can be uniform. Therefore, when fabricating the resonator layer, it is not necessary to use the existing technology of multiple deposition or multiple etching, thereby simplifying the filter fabrication process.

[0094] Figure 5 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention, see reference. Figure 5 Optionally, the filter can be fabricated using the following methods:

[0095] Step 310: Provide a first protective substrate and a second protective substrate; this step is the same as step 110 in the above embodiment, and will not be described again here.

[0096] Step 320: Form at least one resonator layer on one side of the first protective substrate and / or one side of the second protective substrate; this step is the same as step 120 in the above embodiment, and will not be described again here.

[0097] Step 330: Provide an intermediate substrate and form at least one resonator layer on a first side and / or a second side of the intermediate substrate. The first side and the second side of the intermediate substrate are opposite sides of the intermediate substrate.

[0098] Optionally, the material of the intermediate substrate is the same as that of the first protective substrate and / or the second protective substrate. In this step, at least one resonator layer can be formed on the first side and the second side of the intermediate substrate, or at least one resonator layer can be formed only on the first side or the second side. This embodiment does not make specific limitations here.

[0099] Step 340: Bond the first protective substrate and the intermediate substrate on the first side of the intermediate substrate using a bonding structure.

[0100] Specifically, the first protective substrate and the intermediate substrate are bonded on the first side of the intermediate substrate by a bonding structure. This can be achieved by bonding at least one of the surface of the first protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first protective substrate, to at least one of the surface of the intermediate substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first side of the intermediate substrate.

[0101] Step 350: Bond the second protective substrate to the intermediate substrate on the second side of the intermediate substrate using a bonding structure.

[0102] Specifically, the second protective substrate and the intermediate substrate are bonded on the second side of the intermediate substrate by a bonding structure. This can be achieved by bonding at least one of the surface of the second protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate, to at least one of the surface of the intermediate substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second side of the intermediate substrate.

[0103] It should be noted that, in this embodiment, if at least one resonator layer is formed on both the first and second sides of the intermediate substrate in step 330, then at least one resonator layer can be formed on the first side of the intermediate substrate first, and step 340 can be performed after forming at least one resonator layer on the first side of the intermediate substrate, and then at least one resonator layer can be formed on the second side of the intermediate substrate, and then step 350 can be performed; alternatively, at least one resonator layer can be formed on the second side of the intermediate substrate first, and then step 350 can be performed, and then at least one resonator layer can be formed on the first side of the intermediate substrate, and then step 340 can be performed after forming at least one resonator layer on the first side of the intermediate substrate.

[0104] The following description uses the example of forming a resonator layer on both the first and second sides of an intermediate substrate. First, a resonator layer is formed on the first side of the intermediate substrate. After forming the resonator layer on the first side of the intermediate substrate, step 340 is performed. Then, a resonator layer is formed on the second side of the intermediate substrate, and step 350 is performed.

[0105] Figure 6This is a schematic diagram of the structure after the first protective substrate and the first side of the intermediate substrate are bonded together using a bonding structure. During bonding, sub-bonding structures can be provided at least near the edge of the surface on the first side of the first protective substrate 210 where the resonator layer 220 is formed, and at least near the edge of the surface on the intermediate substrate 250 where the resonator layer 220 is formed. When a portion of the resonator layer 220's film structure exists at the location where the sub-bonding structure is to be provided on the first protective substrate 210 or the intermediate substrate 250, the sub-bonding structure can be provided on the resonator's film structure. Optionally, the orthographic projection of the sub-bonding structure onto the corresponding substrate is a closed shape, such as a ring or a frame, and the orthographic projection of each resonator included in the resonator layer 220 onto the corresponding substrate is surrounded by the sub-bonding structure. A complete bonding structure 240 is obtained by bonding the sub-bonding structure of the first protective substrate 210 with the sub-bonding structure of the intermediate substrate 250. The sub-bonding structures of the first protective substrate 210 and the intermediate substrate 250 correspond in the thickness direction of the filter to ensure that they can be bonded together.

[0106] Figure 7 This is a schematic diagram of the structure after forming a resonator layer on the second side of the intermediate substrate according to an embodiment of the present invention. The first and second sides of the intermediate substrate 250 are opposite sides of the intermediate substrate 250. In this embodiment, by forming resonator layers on both the first and second sides of the intermediate substrate 250, an additional intermediate substrate 250 can be added between the first protective substrate 210 and the second protective substrate 230. This allows for the addition of at least two resonator layers in the filter, thereby ensuring a relatively large number of resonator layers while requiring fewer substrates. This helps reduce the thickness of the filter itself and further improves the integration density of the filter.

[0107] Figure 8This is a schematic diagram of a filter obtained by bonding the second protective substrate to the second side of the intermediate substrate using a bonding structure. During bonding, sub-bonding structures can be provided at least near the edge of the surface of the second protective substrate 230, and at least near the edge of the surface of the resonator layer on the second side of the intermediate substrate 250. Optionally, when a portion of the resonator layer 220's film structure exists at the location where the sub-bonding structure is to be provided on the second protective substrate 230 or the intermediate substrate 250, the sub-bonding structure can be provided on the resonator's film structure. Optionally, the orthographic projection of the sub-bonding structure onto the corresponding substrate is a closed shape, such as a ring or frame, and the orthographic projections of each resonator included in the resonator layer 220 onto the corresponding substrate are surrounded by the sub-bonding structure. A complete bonding structure 240 is obtained by bonding the sub-bonding structure of the second protective substrate 230 with the sub-bonding structure of the intermediate substrate 250. The sub-bonding structures of the second protective substrate 230 and the intermediate substrate 250 correspond in the thickness direction of the filter to ensure that they can be bonded together.

[0108] It should be noted that, Figure 8 Taking an example where no resonator layer is formed on either the surface of the second protective substrate 230 near the first protective substrate 210 or the surface away from the first protective substrate 210, in other optional embodiments of the present invention, a resonator layer may be formed on the surface of the second protective substrate 230 near the first protective substrate 210 and / or the surface away from the first protective substrate 210. When a resonator layer is formed on the surface of the second protective substrate 230 near the first protective substrate 210, the connection between the second protective substrate 210 and the resonator layer on the second side of the intermediate substrate 250 via a bonding structure is achieved by connecting the resonator layer on the surface of the second protective substrate 210 near the first protective substrate 210 with the resonator layer on the second side of the intermediate substrate 250 via a bonding structure.

[0109] It should be noted that the above embodiments are only illustrated by the example of a filter including one intermediate substrate. In other optional embodiments of the present invention, the filter may include multiple intermediate substrates. At least one resonator layer may be formed on the first side and / or the second side of each intermediate substrate. After bonding each intermediate substrate, one of the two outermost intermediate substrates is bonded to the first protective substrate and the other is bonded to the second protective substrate.

[0110] Figure 9 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention, see reference. Figure 10 Optionally, the filter can be fabricated using the following methods:

[0111] Step 410: Provide a first protective substrate and a second protective substrate; this step is the same as step 110 in the above embodiment, and will not be described again here.

[0112] Step 420: Form at least one resonator layer on one side of the second protective substrate. The structure after forming a resonator layer on one side of the second protective substrate can still be referenced. Figure 3 .

[0113] Step 430: Form at least two resonator layers layer by layer on one side of the first protective substrate;

[0114] Optionally, step 430 includes:

[0115] A first resonator layer is formed on one side of the first protective substrate;

[0116] A second resonator layer adjacent to the first resonator layer is formed on the side of the first resonator layer away from the first protective substrate.

[0117] Figure 10 This is a schematic diagram of the structure after two resonator layers are formed on one side of the first protective substrate. In this step, at least two resonator layers 220 are formed on one side of the first protective substrate 210. To avoid unnecessary contact between adjacent resonator layers 220, after forming a first resonator layer 224 on one side of the first protective substrate 210, a second resonator layer 225 adjacent to the first resonator layer 224 is formed on the side of the first resonator layer 224 away from the first protective substrate, including:

[0118] A capping layer 203 is formed on the side of the first resonator layer 224 away from the first protective substrate 210, and a second resonator layer 225 is formed on the side of the capping layer 203 away from the first protective substrate 210.

[0119] Before forming the second resonator layer 225 on the side of the cap layer 203 away from the first protective substrate 210, a connection structure 204 is formed that connects the first resonator layer 224 and the second resonator layer 225 through the cap layer 203.

[0120] The first resonator layer 224 and the second resonator layer 225 are any two adjacent resonator layers formed on one side of the first protective substrate 210. By providing a capping layer 203 between adjacent resonator layers 220, unnecessary contact between them can be avoided, and electrical connection between the resonators in adjacent resonator layers 220 can be achieved through a connection structure 204 penetrating the capping layer 203. Optionally, the material of the capping layer 203 can be amorphous silicon, polycrystalline silicon, silicon nitride, aluminum oxide, etc.

[0121] Optionally, before forming the capping layer 203 on the side of the first resonator layer 224 away from the first protective substrate 210, the method may further include forming a sacrificial material on the side of the first resonator layer 224 away from the first protective substrate 210. After forming the capping layer 203 on the side of the first resonator layer 224 away from the first protective substrate 210, the method may further include releasing the sacrificial material. Through the above steps, a cavity can be formed between the capping layer 203 and the upper electrode layer 223 of the first resonator layer 224, with at least a portion of the upper electrode layer 223, at least a portion of the piezoelectric layer 222, and at least a portion of the lower electrode layer 221 located within the cavity, thereby protecting the upper electrode layer 223, the piezoelectric layer 222, and the lower electrode layer 221.

[0122] Step 440: Bond the side of the second protective substrate with the resonator layer and the side of the first protective substrate with the resonator layer together using a bonding structure.

[0123] Figure 11 This is a schematic diagram of the filter structure obtained after bonding the second protective substrate and the capping layer. Optionally, in this step, at least one of the surface of the second protective substrate 220 near the first protective substrate 210, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate 220, can be bonded to at least one of the surface of the first protective substrate 210 near the second protective substrate 220, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the first protective substrate 210, or the capping layer on one side of the resonator layer. The filter fabrication method of this embodiment, by providing a capping layer 203 between adjacent resonator layers 220, can reduce the number of substrates in the filter, which is beneficial to reducing the cost of the filter. At the same time, the thickness of the filter can be reduced by thinning the capping layer 203, which is more conducive to miniaturization of the filter.

[0124] Figure 12 This is a flowchart of another filter fabrication method provided in an embodiment of the present invention, see reference. Figure 12 The method for fabricating this filter includes:

[0125] Step 510: Provide a first protective substrate and a second protective substrate;

[0126] Step 520: Form at least one resonator layer and at least one capping layer on one side of the first protective substrate.

[0127] In one embodiment, when a resonator layer and a capping layer are formed on one side of the first protective substrate, the capping layer is located on the side of the resonator layer away from the first protective substrate. In another embodiment, when at least two resonator layers are formed on one side of the first protective substrate, the capping layer is formed between adjacent resonator layers. A structure with two resonator layers and a capping layer formed on one side of the first protective substrate can be referenced. Figure 10 .

[0128] Step 530: Form at least one resonator layer and at least one capping layer on one side of the second protective substrate.

[0129] In this configuration, when a resonator layer and a capping layer are formed on one side of the second protective substrate, the capping layer is located on the side of the resonator layer away from the second protective substrate. When at least two resonator layers are formed on one side of the second protective substrate, the capping layer is formed between adjacent resonator layers. The structure of forming two resonator layers and a capping layer on one side of the second protective substrate is similar to... Figure 10 The structures shown are the same, and will Figure 10 Simply replace the first protective substrate with the second protective substrate.

[0130] Step 540: Bond the side of the first protective substrate with the resonator layer and the side of the second protective substrate with the resonator layer together using a bonding structure.

[0131] The side of the first protective substrate with the resonator layer and the side of the second protective substrate with the resonator layer are bonded together by a bonding structure. This can be achieved by bonding at least one of the following: the surface of the second protective substrate 220 near the first protective substrate 210, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the second protective substrate 220, and the capping layer of the resonator layer on the side away from the second protective substrate 220 to the surface of the first protective substrate 210 near the second protective substrate 220, and the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the first protective substrate 210, and the capping layer of the resonator layer on the side away from the first protective substrate 220.

[0132] Figure 13 This is a schematic diagram of the filter structure obtained by bonding the film layer furthest from the first protective substrate on one side and the film layer furthest from the second protective substrate on one side using a bonding structure according to an embodiment of the present invention. Figure 13 An exemplary illustration shows a case where the film layer furthest from the first protective substrate 210 on one side is a resonator layer, and the film layer furthest from the second protective substrate 230 on one side is a resonator layer. In other optional embodiments of the present invention, the film layer furthest from the first protective substrate 210 on one side can be a capping layer 203, and the film layer furthest from the second protective substrate 230 on one side can also be a capping layer 203.

[0133] In the above embodiments of the present invention, the first protective substrate and / or the second protective substrate in the filter can be a set substrate.

[0134] Figure 14This is a flowchart of forming a resonator layer on one side of a defined substrate, provided in an embodiment of the present invention. (Refer to...) Figure 14 Among them, a resonator layer is formed on one side of the substrate, including:

[0135] Step 610: Form an acoustic reflection structure on one side of the substrate;

[0136] Among them, the acoustic reflection structure 201 can be Figure 4 , Figure 8 , Figure 11 and Figure 13 The cavity near the substrate side of the resonator layer 220 can also be a Bragg reflector layer, etc. Furthermore, the acoustic reflection structure 201 can be disposed inside the substrate or on the surface of the substrate; this embodiment does not impose specific limitations. During the subsequent formation of the resonator layer 220, each position of the acoustic reflection structure 201 can correspond to the formation of a resonator.

[0137] Step 620: On the side of the substrate where the acoustic reflection structure is formed, the lower electrode layer, the piezoelectric layer and the upper electrode layer are formed in sequence.

[0138] Optionally, step 620 above includes:

[0139] (1) A lower electrode layer is formed on the side of the substrate where an acoustic reflection structure is formed by a single deposition process and a single patterning process.

[0140] Specifically, a full layer of lower electrode material can be deposited on one side of the substrate where the acoustic reflection structure is formed. Within one resonator layer, the thickness of the deposited lower electrode material can be uniform. Then, the entire lower electrode material layer is patterned to obtain the lower electrode layer, which also has a uniform thickness.

[0141] (2) A piezoelectric layer is formed on the side of the lower electrode layer away from the set substrate using a single deposition process and a single patterning process.

[0142] Specifically, a full layer of piezoelectric material can be deposited on the side of the piezoelectric layer away from the substrate. In one of the resonator layers, the thickness of the deposited piezoelectric material can be uniform. Then, the entire piezoelectric material is patterned to obtain a piezoelectric layer, and the thickness of the piezoelectric layer is also uniform.

[0143] (3) An upper electrode layer is formed on the side of the piezoelectric layer away from the substrate by a single deposition process and a single patterning process.

[0144] Specifically, an entire layer of top electrode material can be deposited on the side of the piezoelectric layer away from the substrate. In one of the resonator layers, the thickness of the deposited top electrode material can be uniform. Then, the entire layer of top electrode material is patterned to obtain the top electrode layer, which also has a uniform thickness.

[0145] When forming the lower electrode layer, it is necessary to ensure that the lower electrode layer at least partially covers the acoustic reflection structure. Furthermore, when the acoustic reflection structure is a cavity structure, the sacrificial material in the cavity structure can be released after the upper electrode layer is formed.

[0146] When depositing different resonator layers in a filter, the deposition thickness of the upper electrode layer, piezoelectric layer, and lower electrode layer in the resonator layer can be controlled, so that the thickness of the upper electrode layer, piezoelectric layer, or lower electrode layer of at least two resonator layers in the filter is different. Thus, the thickness of the mass load layer can be controlled by controlling the thickness of the film structure in the resonator layer. Furthermore, the upper electrode layer, piezoelectric layer, and lower electrode layer can all be formed with only one deposition and one patterning process, making the fabrication process relatively simple.

[0147] It should be noted that, in other embodiments of the present invention, when forming a resonator layer on one side of the intermediate substrate or capping layer, the above-described method of forming a resonator layer on one side of the set substrate (i.e., first forming an acoustic reflection structure, and then sequentially forming a lower electrode layer, a piezoelectric layer, and an upper electrode layer on one side of the acoustic reflection structure) can also be adopted.

[0148] This invention also provides a filter, which is fabricated by the fabrication method of any of the above embodiments of this invention. (See reference) Figure 4 The filter includes:

[0149] A first protective substrate 210 and a second protective substrate 230 along the filter thickness direction y1, and at least two resonator layers 220 disposed between the first protective substrate 210 and the second protective substrate 230 along the filter thickness direction y1.

[0150] The resonator layer 220 includes a lower electrode layer 221, a piezoelectric layer 222, and an upper electrode layer 223 stacked together. The thickness of corresponding set film layers in at least two resonator layers 220 is different. The set film layer is at least one of the lower electrode layer 221, the upper electrode layer 223, and the piezoelectric layer 222.

[0151] The filter of this embodiment includes at least two resonator layers disposed between a first protective substrate and a second protective substrate along the filter thickness direction. The corresponding design films in the at least two resonator layers have different thicknesses, and the design films are at least one of a lower electrode layer, an upper electrode layer, and a piezoelectric layer. This embodiment allows control of the mass load layer thickness by controlling the thickness of the design films deposited in different resonator layers, and the mass load layer thickness can be measured by calculating the thickness difference between the design films of different resonator layers. Therefore, the thickness of the mass load layer can be precisely controlled and measured, which is beneficial for precise frequency tuning of the resonator layers, and thus for precise control of the filter frequency. Furthermore, the filter of this embodiment controls the mass load layer thickness by controlling the thickness difference of the design films in different resonator layers. Therefore, for the same resonator layer, the thickness of the lower electrode layer can be uniform, the thickness of the piezoelectric layer can be uniform, and the thickness of the upper electrode layer can be uniform. Therefore, when fabricating the resonator layer, it is not necessary to use the multiple deposition or etching methods of the prior art, thereby simplifying the filter fabrication process.

[0152] Continue to refer to Figure 4 Optionally, the resonator layer 220 includes a plurality of resonators 202. The resonator 202 includes a lower electrode 2211 located in the lower electrode layer 221, a piezoelectric unit located in the piezoelectric layer 222, and an upper electrode 2231 located in the upper electrode layer 223. The thickness of the same film layer of each resonator 202 in the same resonator layer 220 is the same.

[0153] Specifically, the upper electrode 2231 of each resonator 202 in the same resonator layer 220 has the same thickness, the lower electrode 2211 of each resonator 202 in the same resonator layer 220 has the same thickness, and the piezoelectric unit of each resonator 202 in the same resonator layer 220 has the same thickness. By ensuring that the thickness of the same film layer is the same for each resonator 202 in the same resonator layer 220, compared to the existing technology where multiple resonators 202 are laid flat on one side of the substrate and the thickness of the same film layer in multiple resonators 202 varies, the fabrication of a resonator layer 220 only requires one deposition for one film layer (which can be the upper electrode layer 223, the lower electrode layer 221, or the piezoelectric layer 222), eliminating the need for multiple depositions and / or etchings to form the same film layer structure of different thicknesses, thus simplifying the process.

[0154] In other alternative embodiments of the present invention, the thickness of the same film layer of at least two resonators 202 in the same resonator layer 220 may be different, and the present invention does not specifically limit this.

[0155] Continue to refer to Figure 4Optionally, at least some of the adjacent resonator layers 220 are bonded together by a bonding structure 240.

[0156] Specifically, the bonding structure 240 can be used to connect adjacent resonator layers 220.

[0157] This invention also provides another filter, see reference. Figure 8 Optionally, the filter further includes at least one intermediate substrate 250, which is disposed between the first protective substrate 210 and the second protective substrate 230; a resonator layer 220 is disposed on the side of the intermediate substrate 250 that is close to the first protective substrate 210 and / or away from the first protective substrate 210.

[0158] The first protective substrate 210 is bonded to the adjacent intermediate substrate 250 through a bonding structure 240, and the second protective substrate 230 is bonded to the adjacent intermediate substrate 250 through a bonding structure 240.

[0159] By setting the filter to include at least one intermediate substrate 250 between the first protective substrate 210 and the second protective substrate 230, and providing a resonator layer on the side of the intermediate substrate 250 close to and / or far from the first protective substrate 210, more resonator layers can be integrated between the first protective substrate 210 and the second protective substrate 230, which is more conducive to frequency tuning of the filter.

[0160] This invention also provides another filter, see reference. Figure 11 and Figure 13 A capping layer 203 is provided between at least some of the adjacent resonator layers 220, and the resonator layers 220 on both sides of the capping layer 203 are connected by a connecting structure 204 that penetrates the capping layer 203.

[0161] Specifically, by providing a capping layer 203 between adjacent resonator layers 220, it can replace Figure 8 The intermediate substrate 250 in the filter shown can reduce the number of substrates in the filter, which helps to reduce the cost of the filter.

[0162] Optionally, the connection structure 204 is a conductive lead.

[0163] Optionally, the capping layer 203 is formed by deposition. After the capping layer 203 is deposited on a resonator layer 220, adjacent resonator layers 220 can be deposited directly on the capping layer 203. Therefore, there is no need to set bonding structures 240 between adjacent resonator layers 220, which makes the filter structure simpler and reduces the process steps of bonding at least some of the adjacent resonator layers 220 in the filter, thus simplifying the fabrication process.

[0164] Continue to refer to Figure 11 and Figure 13 Optionally, multiple cavities are formed between the cap layer 203 and the upper electrode layer 223 of the resonator layer 220 on the first side. An acoustic reflection structure 201 is provided on the second side of the cap layer 203. The lower electrode layer 221 of the resonator layer 220 on the second side at least partially covers the acoustic reflection structure 201. The first side and the second side are opposite sides of the cap layer 203.

[0165] Continue to refer to Figure 4 , Figure 8 , Figure 11 and Figure 13 Optionally, the bonding structure 240 is a first sealing ring, which is disposed between adjacent substrates. The substrate is any substrate of the filter (which may be a first protective substrate, a second protective substrate, or an intermediate substrate) or a capping layer. The first sealing ring between adjacent substrates forms a sealing structure.

[0166] Specifically, the first sealing ring between adjacent substrates forms a sealing structure, and the resonator 202 in the resonator layer 220 between adjacent substrates is inside the sealing structure, that is, the sealing structure can provide sealing protection for the resonator 202 in the resonator layer 220.

[0167] Figure 15 This is a top view of a filter provided in an embodiment of the present invention, for reference. Figure 15 The resonator layer includes resonators 202 on the substrate ( Figure 14 (Taking the first protective substrate 210 and the second protective substrate 230 as examples for illustration) The orthogonal projection on the substrate is surrounded by the orthogonal projection of the bonding structure 240 on the substrate, thereby ensuring that after bonding, the bonding structure 240 between adjacent substrates forms a sealed structure, preventing the resonator from being corroded by water, oxygen, etc.

[0168] It should be noted that in other optional embodiments of the present invention, the bonding structure may be a different structure from the first sealing ring, as long as the bonding structure can serve a connecting function.

[0169] This embodiment also provides a duplexer. Figure 16 This is a schematic diagram of a duplexer provided in an embodiment of the present invention, for reference. Figure 16 The duplexer includes a transmit filter 601 and a receive filter 602, wherein the transmit filter 601 and / or the receive filter 602 are filters of any of the above embodiments of the present invention.

[0170] The duplexer in this embodiment includes the filter of any of the above embodiments of the present invention, and accordingly possesses the beneficial effects of the filter of any of the above embodiments of the present invention, which will not be repeated here.

[0171] Continue to refer to Figure 16Optionally, the transmit filter 601 and the receive filter 602 are bonded together in the thickness direction y2 of the duplexer.

[0172] In this design, the thickness direction y2 of the duplexer is the same as the thickness direction of the filter. Specifically, the transmitting filter 601 and the receiving filter 602 are bonded together in the thickness direction y2 of the duplexer. This results in a vertical structure for the resonator layer in the filter, and also a vertical structure for the transmitting filter 601 and the receiving filter 602 in the duplexer. This further reduces the planar area occupied by the duplexer, improves the integration of the duplexer, and is more conducive to the miniaturization of the communication system.

[0173] Continue to refer to Figure 16 Optionally, the duplexer also includes a second sealing ring 603, which is located between the transmitting filter 601 and the receiving filter 602, and the transmitting filter 601 and the receiving filter 602 are bonded together by the second sealing ring 603.

[0174] The second sealing ring 603 forms a sealed space with the transmitting filter 601 and the receiving filter 602, thereby sealing and protecting the structures of the transmitting filter 601 and the receiving filter 602 within this sealed space, ensuring the good working performance of the transmitting filter 601 and the receiving filter 602 in the duplexer. Furthermore, the second sealing ring 603 is a commonly used structure in duplexers. By bonding the transmitting filter 601 and the receiving filter 602 using the second sealing ring 603, no additional bonding structure is needed in the duplexer, which helps to further improve the integration density of the duplexer. When bonding the transmitting filter 601 and the receiving filter 602, a second sealing ring 603 can be respectively provided on one side of the transmitting filter 601 and the receiving filter 602, with the second sealing rings 603 corresponding in the substrate thickness direction, and then the two second sealing rings 603 are bonded together.

[0175] Figure 17 This is a schematic diagram of another duplexer provided in an embodiment of the present invention. The transmitting filter 601 and the receiving filter 602 in this duplexer are laid flat on the surface of the substrate 700, and the resonator layer is connected to the circuit 800 on the surface of the substrate 700 by a lead penetrating the substrate 700. The transmitting filter 601 and the receiving filter 602 included in the duplexer of this embodiment are the filters provided in any of the above embodiments of the present invention, and have the beneficial effects of the filters in any of the above embodiments of the present invention.

[0176] This invention also provides a multiplexer, which includes the duplexer provided in any of the above embodiments of this invention.

[0177] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for fabricating a filter, characterized in that, include: Provide a first protective substrate and a second protective substrate; At least one resonator layer is formed on one side of the first protective substrate and / or on one side of the second protective substrate; The first protective substrate and the second protective substrate are connected in the thickness direction of the filter, so that at least two resonator layers are formed between the first protective substrate and the second protective substrate along the thickness direction of the filter. The resonator layer includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer stacked together. At least two resonator layers have corresponding set film layers with different thicknesses. The set film layer is at least one of the lower electrode layer, the upper electrode layer, and the piezoelectric layer. The resonator layer includes multiple resonators, and the thickness of the same film layer of each resonator in the same resonator layer is the same; the thickness of one of the corresponding film layers of each resonator in different resonator layers is different; the thickness of the mass load layer can be controlled by controlling the thickness of at least one of the upper electrode layer, lower electrode layer, and piezoelectric layer of different resonator layers, so as to perform precise frequency correction for each resonator layer individually.

2. The method for fabricating the filter according to claim 1, characterized in that, Before connecting the first protective substrate and the second protective substrate in the filter thickness direction to form at least two resonator layers disposed along the filter thickness direction between the first protective substrate and the second protective substrate, the method further includes: An intermediate substrate is provided, and at least one resonator layer is formed on a first side and / or a second side of the intermediate substrate; wherein the first side and the second side of the intermediate substrate are opposite sides of the intermediate substrate; The step of connecting the first protective substrate and the second protective substrate in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, includes: The first protective substrate and the intermediate substrate are bonded together on the first side of the intermediate substrate by a bonding structure; The second protective substrate and the intermediate substrate are bonded to each other on the second side of the intermediate substrate by a bonding structure.

3. The method for fabricating the filter according to claim 2, characterized in that, The step of bonding the first protective substrate and the intermediate substrate to a first side of the intermediate substrate using a bonding structure includes: At least one of the surface of the first protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first protective substrate, is bonded to at least one of the surface of the intermediate substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the first side of the intermediate substrate. The step of bonding the second protective substrate and the intermediate substrate to the second side of the intermediate substrate using a bonding structure includes: At least one of the surface of the second protective substrate near the intermediate substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate, is bonded to at least one of the surface of the intermediate substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second side of the intermediate substrate.

4. The method for fabricating a filter according to claim 1, characterized in that, The formation of a resonator layer on one side of the first protective substrate and / or one side of the second protective substrate includes: At least one resonator layer is formed on one side of the second protective substrate; At least two resonator layers are formed layer by layer on one side of the first protective substrate; The step of connecting the first protective substrate and the second protective substrate in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, includes: The side of the second protective substrate with the resonator layer and the side of the first protective substrate with the resonator layer are bonded together by a bonding structure.

5. The method for fabricating a filter according to claim 4, characterized in that, The step of forming at least two resonator layers on one side of the first protective substrate includes: forming a first resonator layer on one side of the first protective substrate; and forming a second resonator layer adjacent to the first resonator layer on the side of the first resonator layer away from the first protective substrate. After forming a first resonator layer on one side of the first protective substrate, a second resonator layer adjacent to the first resonator layer is formed on the side of the first resonator layer away from the first protective substrate, including: A capping layer is formed on the side of the first resonator layer away from the first protective substrate, and a second resonator layer is formed on the side of the capping layer away from the first protective substrate.

6. The method for fabricating a filter according to claim 5, characterized in that, The step of bonding the side of the second protective substrate where the resonator layer is disposed and the side of the first protective substrate where the resonator layer is disposed through a bonding structure includes: The second protective substrate is bonded to at least one of the surface of the second protective substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, and the piezoelectric layer of the resonator layer disposed on the second protective substrate, and to at least one of the surface of the first protective substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the first protective substrate, or the capping layer on one side of the resonator layer.

7. The method for fabricating a filter according to claim 5, characterized in that, Before forming a capping layer on the side of the first resonator layer away from the first protective substrate, the method further includes: A sacrificial material is formed on the side of the first resonator layer away from the first protective substrate; After forming a capping layer on the side of the first resonator layer away from the first protective substrate, the method further includes: The sacrificial material is released.

8. The method for fabricating a filter according to claim 1, characterized in that, At least one resonator layer is formed on one side of the first protective substrate and / or one side of the second protective substrate, including: An acoustic reflection structure is formed on one side of a substrate, wherein the substrate is the first protective substrate and / or the second protective substrate; A lower electrode layer, a piezoelectric layer, and an upper electrode layer are sequentially formed on the side of the substrate where the acoustic reflection structure is formed. Preferably, a lower electrode layer, a piezoelectric layer, and an upper electrode layer are sequentially formed on the side of the substrate where the acoustic reflection structure is formed, including: The lower electrode layer is formed on the side of the substrate where the acoustic reflection structure is formed using a single deposition process and a single patterning process. The piezoelectric layer is formed on the side of the lower electrode layer away from the designated substrate using a single deposition process and a single patterning process; The upper electrode layer is formed on the side of the piezoelectric layer away from the designated substrate using a single deposition process and a single patterning process.

9. The method for fabricating a filter according to claim 1, characterized in that, Forming at least one resonator layer on one side of the first protective substrate and / or one side of the second protective substrate includes: forming at least one resonator layer and at least one capping layer on one side of the first protective substrate; At least one resonator layer and at least one capping layer are formed on one side of the second protective substrate; The step of connecting the first protective substrate and the second protective substrate in the thickness direction of the filter, so that at least two resonator layers disposed along the thickness direction of the filter are formed between the first protective substrate and the second protective substrate, includes: The side of the first protective substrate with the resonator layer and the side of the second protective substrate with the resonator layer are bonded together by a bonding structure.

10. The method for fabricating a filter according to claim 9, characterized in that, The step of bonding the side of the first protective substrate where the resonator layer is disposed and the side of the second protective substrate where the resonator layer is disposed through a bonding structure includes: At least one of the following: the surface of the first protective substrate near the second protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the first protective substrate, and the capping layer, is bonded to at least one of the following: the surface of the second protective substrate near the first protective substrate, the upper electrode layer, the lower electrode layer, the piezoelectric layer of the resonator layer disposed on the second protective substrate, and the capping layer.

11. A filter, characterized in that, include: A first protective substrate and a second protective substrate along the thickness direction of the filter, and at least two resonator layers disposed between the first protective substrate and the second protective substrate along the thickness direction of the filter; Wherein, at least some of the adjacent resonator layers are bonded together by a bonding structure; the filter further includes at least one intermediate substrate, the intermediate substrate being disposed between the first protective substrate and the second protective substrate; the resonator layers are disposed on the side of the intermediate substrate close to and / or away from the first protective substrate; The first protective substrate is bonded to the adjacent intermediate substrate through the bonding structure, and the second protective substrate is bonded to the adjacent intermediate substrate through the bonding structure. The resonator layer includes a lower electrode layer, a piezoelectric layer, and an upper electrode layer stacked together. The thickness of corresponding set film layers in at least two resonator layers is different. The set film layer is at least one of the lower electrode layer, the upper electrode layer, and the piezoelectric layer. The resonator layer includes multiple resonators, and the thickness of the same film layer of each resonator in the same resonator layer is the same; the thickness of one of the corresponding film layers of each resonator in different resonator layers is different; the thickness of the mass load layer can be controlled by controlling the thickness of at least one of the upper electrode layer, lower electrode layer, and piezoelectric layer of different resonator layers, so as to perform precise frequency correction for each resonator layer individually.

12. The filter according to claim 11, characterized in that, The resonator layer includes multiple resonators, each including a lower electrode in the lower electrode layer, a piezoelectric unit in the piezoelectric layer, and an upper electrode in the upper electrode layer. The thickness of the same film layer of each resonator in the same resonator layer is the same.

13. The filter according to claim 11, characterized in that, A capping layer is provided between at least some of the adjacent resonator layers, and the resonator layers on both sides of the capping layer are connected by a connection structure that penetrates the capping layer; Preferably, the connection structure is a conductive lead; Preferably, the capping layer is formed by deposition.

14. The filter according to claim 13, characterized in that, Multiple cavities are formed between the cap layer and the upper electrode layer of the resonator layer on the first side. An acoustic reflection structure is provided on the second side of the cap layer. The lower electrode layer of the resonator layer on the second side at least partially covers the acoustic reflection structure. The first side and the second side are opposite sides of the cap layer.

15. The filter according to claim 14, characterized in that, The bonding structure is a first sealing ring, which is disposed between adjacent substrates. The substrate is any substrate of the filter or the capping layer. The first sealing ring between adjacent substrates forms a sealing structure.

16. A duplexer, characterized in that, It includes a transmit filter and a receive filter, wherein the transmit filter and / or the receive filter is the filter according to any one of claims 9-15.

17. The duplexer according to claim 16, characterized in that, The transmitting filter and the receiving filter are bonded together in the thickness direction of the duplexer.

18. The duplexer according to claim 17, characterized in that, It also includes a second sealing ring, which is located between the transmitting filter and the receiving filter, and the transmitting filter and the receiving filter are bonded together through the second sealing ring.

Images