Bulk acoustic wave device preparation method and device and bulk acoustic wave device

Abstract

The invention provides a bulk acoustic wave device preparation method and device and a bulk acoustic wave device, which can be applied to the technical field of semiconductors. The method comprises the steps that a bulk acoustic wave filter is formed on a silicon-based substrate, and the surface of the bulk acoustic wave filter comprises a plurality of electrode connection areas; convex point structures are respectively formed in the plurality of electrode connection areas; based on the plurality of bump structures, packaging the bulk acoustic wave filter on the substrate to obtain a first bulk acoustic wave device; depositing a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and performing film coating treatment on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and more particularly, to a method and apparatus for manufacturing a bulk acoustic wave device and a bulk acoustic wave device. Background Art

[0002] During the manufacturing process of a bulk acoustic wave device (BAW), due to factors such as the uniformity of thin film or etching processes, the thickness of a single wafer obtained cannot be made exactly the same in different regions thereof, that is, the operating frequencies of bulk acoustic wave filters in different regions on a single wafer cannot be exactly the same. To solve this problem, in related technologies, materials with low acoustic loss, such as AlN (aluminum nitride), are usually used to form a passivation layer on the top of the bulk acoustic wave filter during the manufacturing process, and then surface etching treatment is performed on the passivation layer by means of ion beam etching or the like to correct the operating frequency of the bulk acoustic wave filter.

[0003] However, in practical applications, the AlN (aluminum nitride) material will undergo a slow hydrolysis reaction in a water vapor environment, resulting in a change in the operating frequency of the bulk acoustic wave device over time and affecting the reliability of the device. In related technologies, a wafer-level packaging method with extremely high sealing performance is usually used to form a sealing structure on the bulk acoustic wave filter. However, this wafer-level packaging method has a complex process and the required equipment is expensive, indirectly reducing the yield rate of manufacturing the acoustic wave filter module and increasing the manufacturing cost of the acoustic wave filter module. Summary of the Invention

[0004] In view of this, the present disclosure provides a method and apparatus for manufacturing a bulk acoustic wave device and a bulk acoustic wave device.

[0005] One aspect of the present disclosure provides a method for manufacturing a bulk acoustic wave device, including:

[0006] forming a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions;

[0007] forming bump structures in each of the plurality of electrode connection regions;

[0008] encapsulating the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device;

[0009] depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and

[0010] performing a film coating process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

[0011] According to an embodiment of the present disclosure, depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes:

[0012] Using an atomic layer deposition method to form the protective layer on the surface of the first bulk acoustic wave device to obtain the second bulk acoustic wave device, wherein the thickness of the protective layer is between 1 nm and 100 nm.

[0013] According to an embodiment of the present disclosure, the material of the protective layer is Al2O3, SiO2 or Si3N4.

[0014] According to an embodiment of the present disclosure, the substrate includes a bottom electrode;

[0015] The above method further includes:

[0016] Before depositing and forming a protective layer on the surface of the first bulk acoustic wave device, coating a protective film layer on the surface of the bottom electrode of the first bulk acoustic wave device based on the position of the bottom electrode; and

[0017] Before performing a film covering process on the second bulk acoustic wave device, performing an etching process on the second bulk acoustic wave device to remove the protective film layer and the protective layer in the area of the bottom electrode.

[0018] According to an embodiment of the present disclosure, the surface of the electrode connection layer includes the plurality of electrode connection regions.

[0019] According to an embodiment of the present disclosure, depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes:

[0020] Using an atomic layer deposition method to form the protective layer on the plurality of surfaces of the first bulk acoustic wave device and the inner surface of the cavity structure respectively to obtain the second bulk acoustic wave device, wherein the thickness of the protective layer is between 1 nm and 100 nm.

[0021] According to an embodiment of the present disclosure, encapsulating the bulk acoustic wave filter on the substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device includes:

[0022] Based on the position of the bulk acoustic wave filter, cutting the silicon-based substrate to obtain grains related to the bulk acoustic wave filter;

[0023] Based on the plurality of bump structures, mounting and soldering the grains on the substrate by surface mount technology to obtain the first bulk acoustic wave device.

[0024] Another aspect of the present disclosure provides a bulk acoustic wave device manufacturing apparatus, including:

[0025] The first preparation module is configured to form a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions;

[0026] The second preparation module is configured to form bump structures on each of the plurality of electrode connection regions;

[0027] The third preparation module is configured to package the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device;

[0028] The fourth preparation module is configured to deposit a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and

[0029] The fifth preparation module is configured to perform a film covering process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

[0030] Another aspect of the present disclosure provides a bulk acoustic wave device obtained by the method for preparing a bulk acoustic wave device according to any one of the above.

[0031] According to an embodiment of the present disclosure, when preparing a bulk acoustic wave device by the above method for preparing a bulk acoustic wave device, there is no need to perform WLP (Wafer Level Package) packaging. After forming a bulk acoustic wave filter on a silicon-based substrate, bump structures are directly formed on each of the plurality of electrode connection regions, and then the bulk acoustic wave filter is packaged on a substrate to obtain a first bulk acoustic wave device. When packaging the bulk acoustic wave filter on the substrate, since the bump structures formed on each of the plurality of electrode connection regions have a height, a cavity will be formed. Then, a protective layer is deposited on all exposed surfaces of the first bulk acoustic wave device by Atomic Layer Deposition (ALD) technology. A waterproof material layer or multiple layers is applied to the entire substrate with mounted chips, and then a film covering package is performed on the device to finally obtain a target bulk acoustic wave device. By adding a protective layer, it is possible to prevent the surface film layer of the bulk acoustic wave filter, such as the passivation layer ALN, from being hydrolyzed, improving the device reliability while reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0033] Figure 1 Schematically shows a flowchart of a method for preparing a bulk acoustic wave device according to an embodiment of the present disclosure;

[0034] Figure 2 Schematically shows a schematic diagram of a bulk acoustic wave filter according to an embodiment of the present disclosure;

[0035] Figure 3Schematically shows a schematic diagram of an SMR type bulk acoustic wave filter according to an embodiment of the present disclosure.

[0036] Figure 4 Schematically shows a schematic diagram of a bulk acoustic wave filter with a bump structure according to an embodiment of the present disclosure;

[0037] Figure 5 Schematically shows a schematic diagram of a first bulk acoustic wave device according to an embodiment of the present disclosure;

[0038] Figure 6 Schematically shows a schematic diagram of the first bulk acoustic wave device after coating a protective film layer according to an embodiment of the present disclosure;

[0039] Figure 7 Schematically shows a schematic diagram of a second bulk acoustic wave device according to an embodiment of the present disclosure;

[0040] Figure 8 Schematically shows a schematic diagram of the second bulk acoustic wave device after etching treatment according to an embodiment of the present disclosure;

[0041] Figure 9 Schematically shows a schematic diagram of a target bulk acoustic wave device according to an embodiment of the present disclosure; and

[0042] Figure 10 Schematically shows a block diagram of a bulk acoustic wave device manufacturing apparatus according to an embodiment of the present disclosure Detailed Description of the Invention

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

[0044] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0045] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0046] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0047] Bulk acoustic wave filters include two types: solid-state assembled bulk acoustic wave filters (SMR Bulk Acoustic Wave Filter) and air-gap bulk acoustic wave filters (Film Bulk Acoustic Resonator, FBAR). In the process of fabricating air-gap bulk acoustic wave devices, generally, AlN material is used as the passivation layer and also has the function of frequency modulation. In related technologies, a wafer-level packaging method with extremely high sealing performance is often used to form a sealing structure on the bulk acoustic wave filter to improve the reliability of the device. For example, a metal sealing ring is formed around the device, and a silicon wafer or a glass wafer is bonded as the cover of the bulk acoustic wave filter by using gold-gold bonding / gold-tin bonding / copper-tin bonding, etc. Then, the device I / O ports that need to be circuit-connected are led above the cover plate or to the bottom of the substrate through Through Silicon Via (TSV) to be connected to other circuits. Then, the bonded wafer is ball-implanted and cut into chips, which are mounted on a substrate, and then covered with a film to form a complete filter chip.

[0048] In the process of implementing the concept of the present disclosure, the inventors found that there are at least the following problems in the related technologies:

[0049] 1) The bonding of the wafer-level metal sealing ring requires ensuring that the entire bulk acoustic wave filter is sealed by a large number of sealing rings. At the same time, if good sealing performance during the bonding process is to be ensured, the process used is of high difficulty. Moreover, corresponding to the extremely high flatness and metal layer film formation uniformity requirements for bulk acoustic wave devices, expensive Chemical Mechanical Polishing (CMP) equipment and metal film formation equipment also need to be matched. In related technologies, it is difficult to achieve a high bonding yield, and the failure probability of bulk acoustic wave devices is relatively high.

[0050] 2) A sealing metal ring with a certain width needs to be set around the bulk acoustic wave device, which will cause an increase in the chip size, a decrease in the yield of bulk acoustic wave devices produced per single wafer, and an increase in production costs.

[0051] 3) The WLP packaging structure requires an additional wafer to be used as the cover. In order to make the bonding more stable, precious metals are generally used as the bonding material, such as gold. Moreover, the electrical connection needs to be led out through TSV holes, resulting in a significant increase in manufacturing costs.

[0052] In view of this, embodiments of the present disclosure provide a method and apparatus for manufacturing a bulk acoustic wave device and a bulk acoustic wave device. The method includes forming a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions; forming bump structures on each of the plurality of electrode connection regions; encapsulating the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device; depositing a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and performing a film coating process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

[0053] Figure 1 FIG. schematically shows a flowchart of a method for manufacturing a bulk acoustic wave device according to an embodiment of the present disclosure.

[0054] As Figure 1 shown, the method includes operations S110 to S150.

[0055] In operation S110, a bulk acoustic wave filter is formed on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions.

[0056] In operation S120, bump structures are formed on each of the plurality of electrode connection regions.

[0057] In operation S130, based on the plurality of bump structures, the bulk acoustic wave filter is encapsulated on a substrate to obtain a first bulk acoustic wave device.

[0058] In operation S140, a protective layer is deposited on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device.

[0059] In operation S150, a film coating process is performed on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

[0060] According to an embodiment of the present disclosure, a bulk acoustic wave filter can be formed through the following steps. First, a suitable silicon-based substrate is selected and surface treatment such as cleaning and removing surface impurities is performed. Using a suitable deposition technique, a bottom electrode layer is deposited on the silicon-based substrate. Using photolithography techniques and etching processes, the positions and shapes of the electrode connection regions are defined on the bottom electrode layer. An upper electrode layer is deposited on the piezoelectric layer. The upper electrode is generally similar to the bottom electrode and sandwiches the piezoelectric layer with the bottom electrode to generate a bulk acoustic wave filtering effect, thereby obtaining a bulk acoustic wave filter.

[0061] According to an embodiment of the present disclosure, the electrical connection layer of the bulk acoustic wave filter includes a plurality of electrical connection regions. Bump structures are formed on each of the electrode connection regions, and the material for forming the bump structures can be a conductive metal material such as tin or gold. Among them, the bump structures can be formed on the electrical connection regions by means of stencil printing or ball placement, and the bump structures of the electrical connection regions can be formed by means of wire bonding or thermocompression ultrasonic methods.

[0062] According to an embodiment of the present disclosure, a substrate suitable for packaging is designed according to the size and connection requirements of the bulk acoustic wave filter. When ensuring the correct connection between the bulk acoustic wave filter and the circuit on the substrate, the bump structure on the bulk acoustic wave filter is fixed at the corresponding substrate position by SMT or FCT methods, thereby obtaining a first bulk acoustic wave device.

[0063] According to an embodiment of the present disclosure, a protective layer is formed on the first bulk acoustic wave device by ALD to obtain a second bulk acoustic wave device. The purpose of depositing the protective layer on the surface of the first bulk acoustic wave device is to prevent the filter from being affected by the external environment, such as humidity, oxidation, corrosion, etc., thereby affecting the function and performance of the filter. Common protective layer materials include aluminum silicon oxide, silicon nitride, aluminum oxide, etc. ALD technology can be used for deposition. ALD can achieve atomic-level control of the film thickness and composition. The deposited film has a very uniform thickness and composition, and various types of materials can be deposited. Therefore, a uniform and dense protective layer can be obtained by using ALD technology.

[0064] According to an embodiment of the present disclosure, after forming the protective layer on the first bulk acoustic wave device, a film coating is performed. The second bulk acoustic wave device can be wrapped and sealed with an epoxy resin film material to obtain a target bulk acoustic wave device.

[0065] According to an embodiment of the present disclosure, when preparing a bulk acoustic wave device by the above-mentioned bulk acoustic wave device preparation method, no WLP packaging is required. After forming a bulk acoustic wave filter on a silicon-based substrate, bump structures are directly formed in each of the multiple electrode connection regions, and then the bulk acoustic wave filter is packaged on the substrate to obtain a first bulk acoustic wave device. When the bulk acoustic wave filter is packaged on the substrate, since the bump structures formed in each of the multiple electrode connection regions have a height, a cavity will be formed. Then, a protective layer is deposited on all the exposed surfaces of the first bulk acoustic wave device by ALD technology. A waterproof material is applied to the entire substrate with the mounted die for one or more layers, and then the device is packaged with a film coating. Finally, a target bulk acoustic wave device is obtained. By adding a protective layer, it is possible to avoid hydrolysis of the surface film layer of the bulk acoustic wave filter, such as the passivation layer ALN, improve the reliability of the device, and reduce the production cost at the same time.

[0066] Figure 2 A schematic diagram of a FBAR type bulk acoustic wave filter according to an embodiment of the present disclosure is schematically shown.

[0067] According to an embodiment of the present disclosure, forming a bulk acoustic wave filter on a silicon-based substrate includes: etching a cavity structure on the silicon-based substrate; filling a sacrificial layer material in the cavity structure to obtain a sacrificial layer; sequentially forming a seed layer, a lower electrode layer, a piezoelectric layer, an upper electrode layer, a passivation layer, and an electrode connection layer from the surface of the sacrificial layer upward; and releasing the sacrificial layer material through a release structure to obtain a bulk acoustic wave filter.

[0068] As shown Figure 2 in the figure, a pit, i.e., a cavity structure 21, is etched on a silicon-based substrate. A sacrificial layer material is filled in the pit, and the filled sacrificial layer material can be polished flat by CMP. Then, a seed layer 22, a lower electrode layer 23, a piezoelectric layer 24, an upper electrode layer 25, a passivation layer 26, and an electrode connection layer 27 are formed in sequence. Then, the sacrificial layer material is released to form a cavity, thereby forming a bulk acoustic wave filter. According to an embodiment of the present disclosure, a sacrificial layer material can be filled into the cavity structure on the substrate. The sacrificial layer material can be related to the sacrificial layer removal liquid selected when removing the sacrificial layer material by wet etching, that is, the sacrificial layer material can be selected as a material that is easy to react with the sacrificial layer removal liquid and has no solid residue after the reaction. For example, the sacrificial layer removal liquid can be selected as HF (hydrofluoric acid), BOE (Buffered Oxide etchant), etc. Correspondingly, the sacrificial layer material can be selected as a material that is easy to react with HF, BOE, etc., such as SiO2 (silicon dioxide), PSG (Phospho-Silicate Glass), BPSG (Boro-Phospho-Silicate Glass), etc.

[0069] According to an embodiment of the present disclosure, in the process of forming the lower electrode layer and the upper electrode layer, a metal material with a higher conductivity and a smaller acoustic loss can be used as the plating material, such as Mo (molybdenum), Al (aluminum), W (tungsten), etc. That is, the material of the lower electrode layer or the upper electrode layer is Mo, Al, or W. In the process of forming the piezoelectric layer, a material with a smaller acoustic loss can be used as the plating material, such as AlN, PZT (lead zirconate titanate), ZnO (zinc oxide), etc. That is, the piezoelectric layer material can be AlN, PZT, or ZnO. Optionally, the piezoelectric layer material can also be a material doped with other rare metals, which is not limited herein.

[0070] Figure 3 Schematically shows a schematic diagram of an SMR type bulk acoustic wave filter according to an embodiment of the present disclosure.

[0071] According to an embodiment of the present disclosure, forming a bulk acoustic wave filter on a silicon-based substrate includes: forming a reflection structure on the surface of the silicon-based substrate, where the reflection structure is composed of multiple reflective film layers; and sequentially forming a seed layer, a lower electrode layer, a piezoelectric layer, an upper electrode layer, a passivation layer, and an electrode connection layer upward from the surface of the reflection structure to obtain a bulk acoustic wave filter.

[0072] As Figure 3As shown, the method for manufacturing a bulk acoustic wave device according to the present disclosure is applicable not only to FBAR type bulk acoustic wave filters, but also to SMR type bulk acoustic wave filters. The SMR type bulk acoustic wave filter includes a reflective structure 11, wherein the impedance layer 11 is formed by alternately stacking a high-impedance layer and a low-impedance layer. Then, a seed layer 22, a lower electrode layer 23, a piezoelectric layer 24, an upper electrode layer 25, a passivation layer 26, and an electrode connection layer 27 are sequentially formed upward.

[0073] Figure 4 Schematically shows a schematic diagram of a bulk acoustic wave filter with a bump structure according to an embodiment of the present disclosure.

[0074] As Figure 4 shown, a bump structure 41 is provided on the electrode connection layer. The bump structure 41 can be a metal conductive ball made of tin material or gold material.

[0075] Figure 5 Schematically shows a schematic diagram of a first bulk acoustic wave device according to an embodiment of the present disclosure.

[0076] According to an embodiment of the present disclosure, based on a plurality of bump structures, the bulk acoustic wave filter is encapsulated on a substrate to obtain a first bulk acoustic wave device, including: cutting a silicon-based substrate based on the position of the bulk acoustic wave filter to obtain a die related to the bulk acoustic wave filter; as Figure 5 shown, based on a plurality of bump structures, the die is mounted and soldered on a substrate 51 through surface mount technology to obtain a first bulk acoustic wave device.

[0077] According to an embodiment of the present disclosure, the wafer on which the bump structure is formed is cut. Here, the wafer is the silicon-based substrate in the present disclosure. The wafer is cut into individual dies. Among them, the wafer can be cut by two methods: laser cutting and water jet cutting. After cutting, the individual dies are mounted on the substrate through surface mount technology (SMT) or flip chip technology (FCT), so that the electrode connection area of the filter device is combined with the electrode connection area of the substrate to obtain a first bulk acoustic wave device.

[0078] According to an embodiment of the present disclosure, the substrate includes a bottom electrode; the method for manufacturing a bulk acoustic wave device further includes: before depositing and forming a protective layer on the surface of the first bulk acoustic wave device, coating a protective film layer on the surface of the first bulk acoustic wave device based on the position of the bottom electrode.

[0079] According to an embodiment of the present disclosure, the method of coating the protective film layer preferably uses the method of applying a film. A material that is easily separable from the surface material of the first bulk acoustic wave device can be selected as the film material. According to the actual situation, the film material can be an ultraviolet (UV) film or a blue film to provide the required protection effect.

[0080] Figure 6 Schematically shows a schematic diagram of the first bulk acoustic wave device after coating the protective film layer according to an embodiment of the present disclosure.

[0081] As Figure 6 shown, the material of ALD is insulating. To avoid ALD forming on the electrodes at the bottom of the substrate, resulting in the inability to connect the chip, it is necessary to first apply a layer of film on the bottom of the substrate before performing ALD on the substrate. This film can be a UV film, and the UV film can be directly torn off after ALD is completed.

[0082] According to an embodiment of the present disclosure, coating the protective film layer on the surface of the first bulk acoustic wave device is performed before forming the protective layer. Such a method can provide additional protection for the bottom electrodes on the substrate, ensuring that they are not damaged during the preparation process. This helps to improve the stability and reliability of the first bulk acoustic wave device.

[0083] According to an embodiment of the present disclosure, depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes: using an atomic layer deposition method to form a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device, where the thickness of the protective layer is between 1 nm and 100 nm.

[0084] Figure 7 Schematically shows a schematic diagram of the second bulk acoustic wave device according to an embodiment of the present disclosure.

[0085] According to an embodiment of the present disclosure, depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes: using an atomic layer deposition method to form protective layers on multiple surfaces of the first bulk acoustic wave device and on the inner surfaces of the cavity structures respectively to obtain a second bulk acoustic wave device, where the thickness of the protective layer is between 1 nm and 100 nm. As Figure 7 shown, in the second bulk acoustic wave device compared with the first bulk acoustic wave device, protective layers are formed on the exposed parts of multiple surfaces and on the exposed cavity structure 71.

[0086] According to an embodiment of the present disclosure, Atomic Layer Deposition (ALD) is a thin film preparation technology that can deposit on the surface of a material with atomic layer precision. The ALD method is suitable for forming very thin and uniform thin films and allows precise control of the thickness and composition of the thin film. In this case, to form a protective layer, Al2O3 (aluminum oxide) or SiO2 (silicon dioxide) can be selected as the material for the protective layer. Both of these materials have good chemical stability and insulation properties and can effectively protect the surface of the first bulk acoustic wave device.

[0087] According to an embodiment of the present disclosure, the protective layer can be a single layer or multiple layers of materials. Materials such as AL2O3, SiO2, Si3N4 (silicon nitride), etc., which are insulating and have good waterproof properties, can be selected. During the ALD process, the protective layer with the desired thickness can be achieved by controlling the deposition cycle and the number of cycles of atomic layers.

[0088] According to an embodiment of the present disclosure, by using the ALD method to form an Al2O3 or SiO2 protective layer and controlling its thickness between 1 nm and 100 nm, the preparation of the second bulk acoustic wave device can be achieved. Such a protective layer can provide good surface protection and performance improvement.

[0089] Figure 8 A schematic diagram of the second bulk acoustic wave device after etching treatment according to an embodiment of the present disclosure is schematically shown.

[0090] According to an embodiment of the present disclosure, the method for preparing a bulk acoustic wave device further includes: performing an etching treatment on the second bulk acoustic wave device to remove the protective film layer and the protective layer in the area of the bottom electrode, and cleaning and drying the etched module. Or a film pasting method can be used to form the protective film layer, which can be directly peeled off without etching to expose the area of the bottom electrode.

[0091] As Figure 8 shown, after performing the etching step or the film peeling treatment on the second bulk acoustic wave device, the protective film layer and the protective layer in the area of the bottom electrode are removed, and the Figure 7 shown bulk acoustic wave device is obtained.

[0092] According to an embodiment of the present disclosure, in order to avoid damage to other areas, a local etching method can be used, that is, only the area of the bottom electrode where the protective layer needs to be removed is etched. In addition, after the etching treatment, subsequent steps such as cleaning and drying are required to ensure a clean surface and no residues, which helps the subsequent steps to process this area and ensures the stable performance and reliability of the module.

[0093] Figure 9 A schematic diagram of the target bulk acoustic wave device according to an embodiment of the present disclosure is schematically shown.

[0094] As Figure 9 shown, after forming a protective layer on the substrate, a film is applied. The side of the second bulk acoustic wave device can be wrapped and sealed by an epoxy resin film material, and the surface circuit of the second bulk acoustic wave device is exposed to obtain the packaging structure of the second bulk acoustic wave filter chip, that is, the target bulk acoustic wave device.

[0095] Figure 10 Schematically shows a block diagram of a bulk acoustic wave device manufacturing apparatus according to an embodiment of the present disclosure.

[0096] As Figure 10 shown, the bulk acoustic wave device manufacturing apparatus 1000 includes a first manufacturing module 1010, a second manufacturing module 1020, a third manufacturing module 1030, a fourth manufacturing module 1040, and a fifth manufacturing module 1050.

[0097] The first manufacturing module 1010 is configured to form a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions;

[0098] The second manufacturing module 1020 is configured to form bump structures on each of the plurality of electrode connection regions;

[0099] The third manufacturing module 1030 is configured to encapsulate the bulk acoustic wave filter on the substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device;

[0100] The fourth manufacturing module 1040 is configured to deposit and form a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and

[0101] The fifth manufacturing module 1050 is configured to perform a film coating process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

[0102] It should be noted that the part of the bulk acoustic wave device manufacturing apparatus in the embodiments of the present disclosure corresponds to the part of the bulk acoustic wave device manufacturing method in the embodiments of the present disclosure. For the description of the part of the bulk acoustic wave device manufacturing apparatus, please refer to the part of the bulk acoustic wave device manufacturing method specifically, and details will not be repeated here.

[0103] According to an embodiment of the present disclosure, there is also provided a bulk acoustic wave device manufactured by using the bulk acoustic wave device manufacturing method according to any one of the above embodiments.

[0104] Those skilled in the art will understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0105] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present disclosure.

Claims

1. A method for fabricating a bulk acoustic wave device, comprising: Forming a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions; Forming bump structures on each of the plurality of electrode connection regions; Encapsulating the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device; Depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and Performing a film coating process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

2. The method according to claim 1, wherein, The depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes: Using an atomic layer deposition method to respectively form the protective layer on a plurality of surfaces of the first bulk acoustic wave device to obtain the second bulk acoustic wave device, wherein the thickness of the protective layer is between 1 nm and 100 nm.

3. The method according to claim 1 or 2, wherein The material of the protective layer is Al2O3, SiO2 or Si3N4.

4. The method according to any one of claims 1 to 3, wherein The substrate includes a bottom electrode; The method further includes: Before depositing and forming a protective layer on the surface of the first bulk acoustic wave device, coating a protective film layer on the surface of the first bulk acoustic wave device based on the position of the bottom electrode; and Before performing a film coating process on the second bulk acoustic wave device, etching the second bulk acoustic wave device to remove the protective film layer and the protective layer in the area of the bottom electrode.

5. The method according to claim 1, wherein The forming a bulk acoustic wave filter on a silicon-based substrate includes: Etching to form a cavity structure in the silicon-based substrate; Filling a sacrificial layer material in the cavity structure to obtain a sacrificial layer; Successively forming a seed layer, a lower electrode layer, a piezoelectric layer, an upper electrode layer, a passivation layer and an electrode connection layer from the surface of the sacrificial layer upward; and Releasing the sacrificial layer material through a releasing structure to obtain the bulk acoustic wave filter.

6. The method according to claim 5, wherein, The surface of the electrode connection layer includes the plurality of electrode connection regions.

7. The method according to claim 5, wherein The depositing and forming a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device includes: Using an atomic layer deposition method to respectively form the protective layer on a plurality of surfaces of the first bulk acoustic wave device and the inner surface of the cavity structure to obtain the second bulk acoustic wave device, wherein the thickness of the protective layer is between 1 nm and 100 nm.

8. The method according to claim 1, wherein, The encapsulating the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device includes: Cutting the silicon-based substrate based on the position of the bulk acoustic wave filter to obtain a die related to the bulk acoustic wave filter; Mounting and soldering the die on the substrate through a surface mount technology based on the plurality of bump structures to obtain the first bulk acoustic wave device.

9. A device for fabricating a bulk acoustic wave device, comprising: A first fabrication module for forming a bulk acoustic wave filter on a silicon-based substrate, wherein the surface of the bulk acoustic wave filter includes a plurality of electrode connection regions; A second fabrication module for forming bump structures on each of the plurality of electrode connection regions; A third fabrication module for encapsulating the bulk acoustic wave filter on a substrate based on the plurality of bump structures to obtain a first bulk acoustic wave device; A fourth preparation module, configured to deposit a protective layer on the surface of the first bulk acoustic wave device to obtain a second bulk acoustic wave device; and A fifth preparation module, configured to perform a film coating process on the second bulk acoustic wave device to obtain a target bulk acoustic wave device.

10. A bulk acoustic wave device prepared by using the bulk acoustic wave device preparation method according to any one of claims 1 to 8.

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