A bulk acoustic wave device with high power handling capability and a method of manufacturing the same

Abstract

The application relates to the technical field of radio frequency devices, and particularly discloses a bulk acoustic wave device with high power load capacity and a preparation method thereof. The heat diffusion channel is constructed by arranging the heat dissipation column, and the first micro hole and the second micro hole are arranged to optimize heat dissipation and stress release, so that the heat distribution is managed, the heat accumulation is reduced, and the stress concentration is relieved, thereby improving the power load capacity of the device.

Description

Technical Field

[0001] This application relates to the field of radio frequency device technology, and more specifically, to a bulk acoustic wave device with high power load capability and its fabrication method. Background Technology

[0002] Bulk acoustic wave (BAW) devices, as core filtering and resonant components in radio frequency (RF) front-end systems, play an indispensable role in high-frequency applications such as 5G communication, the Internet of Things (IoT), and satellite navigation. With their compact size, high operating frequency, and high compatibility with semiconductor manufacturing processes, they have become a key component of modern wireless communication equipment.

[0003] With the rapid development of wireless communication technology towards higher frequency bands, larger bandwidths, and higher speeds, the transmission channels of terminal devices, base stations, and radar systems are placing increasingly stringent demands on the power handling capabilities of radio frequency (RF) devices. Driven by high-power RF signals, the piezoelectric layer of traditional cavity-type bulk acoustic wave (BAW) devices experiences significant mechanical stress due to the high-intensity alternating electric field, leading to a sharp rise in localized temperature. Due to the thermal insulation effect of the internal air cavity, heat is difficult to effectively conduct to the external environment, resulting in heat accumulation and subsequently causing piezoelectric layer performance degradation, material fatigue, and even structural failure. Insufficient power capacity has become a core bottleneck restricting the widespread application of such devices in high-performance RF systems.

[0004] In existing technologies, structural optimization techniques such as increasing electrode area or adjusting piezoelectric layer thickness are often used to improve power handling capability. However, while increasing electrode area can distribute some heat load, it inevitably sacrifices the miniaturization advantage of the device and may introduce additional parasitic modes, interfering with frequency response characteristics and signal integrity. Adjusting the piezoelectric layer thickness can easily lead to resonant frequency shift and a decrease in quality factor, while increasing the complexity of process steps and manufacturing costs. These methods, while improving power handling capability, often come at the cost of sacrificing other key electrical performances, resulting in irreconcilable performance trade-offs. Especially in high-power scenarios, the combined effects of inefficient thermal management and stress concentration further exacerbate the reliability risks of the device.

[0005] Therefore, there is an urgent need for a new structural design that can effectively solve the problems of heat accumulation and local stress concentration through innovative heat diffusion channels and stress relief mechanisms while maintaining the compact size and excellent electrical performance of the device, so as to meet the high power load requirements of the next generation of RF systems. Summary of the Invention

[0006] This application provides a bulk acoustic wave device with high power load capability and its fabrication method, aiming to solve the technical problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the solution proposed in this application is as follows: As one aspect of this application, a bulk acoustic wave device with high power load capability is provided, comprising: A substrate in which grooves are formed; A support layer and a functional layer are sequentially stacked on top of the substrate, and an air cavity is formed between the groove and the support layer; A heat dissipation column is disposed within the air cavity and embedded within the substrate, and the heat dissipation column is used to construct a heat diffusion channel for conducting heat from the functional layer to the interior of the substrate; The functional layer includes a bottom electrode, a piezoelectric layer, and a top electrode, which are sequentially stacked on the support layer from bottom to top. The top electrode surface is provided with at least one first micro-opening corresponding to the position of the heat dissipation column, and the first micro-opening completely penetrates the top electrode having a set thickness. The top electrode surface is also provided with at least one second micro-aperture, the second micro-aperture does not completely penetrate the top electrode having a set thickness, and the opening position of the second micro-aperture is located in the device stress concentration area on the top electrode surface.

[0008] Furthermore, the shape of the first micro-aperture is one of the following: plum blossom shape, semi-circular shape, semi-elliptical shape, fan shape, or heart shape; Furthermore, any edge segment on the first micro-aperture is not parallel to any edge segment of the top electrode.

[0009] Furthermore, the number of the first micro-openings is the same as the number of the heat dissipation pillars, and the first micro-openings are configured in a one-to-one correspondence with the heat dissipation pillars; Furthermore, each of the first micro-openings completely covers the cross-section of the corresponding heat dissipation column below it.

[0010] Furthermore, the shape of the second micro-aperture is one of the following: teardrop shape, semi-circular shape, semi-elliptical shape, fan shape, or heart shape; Furthermore, any edge segment on the second micro-aperture is not parallel to any edge segment of the top electrode.

[0011] Furthermore, the bottom of the second micro-aperture has a top electrode material retained; Furthermore, the thickness of the top electrode material should not exceed 50 nm.

[0012] Furthermore, the number of the second micro-apertures is greater than or equal to 1.

[0013] Furthermore, the heat dissipation column is made of silicon nitride, graphene, or a mixture of silicon nitride and graphene.

[0014] Furthermore, the support layer and the heat dissipation column are made of the same material; Furthermore, the support layer and the heat dissipation column are integrally formed.

[0015] Furthermore, the cross-sectional shape of the heat dissipation column is one of the following: square, rectangle, regular polygon, circle, ellipse, semicircle, semi-ellipse, fan-shaped, or heart-shaped. The cross-sectional area of ​​the heat dissipation column does not exceed 20% of the surface area of ​​the top electrode.

[0016] As a second aspect of this application, a method for fabricating a bulk acoustic wave device with high power load capability as described above is provided, comprising: Step S1: Etch a groove on the substrate, deposit a sacrificial layer in the groove, and perform planarization. Step S2: Etch through holes on the sacrificial layer to form through holes for growing heat dissipation pillars, fill the through holes with material and simultaneously deposit material on the sacrificial layer and part of the substrate surface to form an integrated heat dissipation pillar and support layer, and perform planarization treatment. Step S3: Prepare a bottom electrode on the support layer, deposit a piezoelectric layer on the bottom electrode, and prepare a top electrode on the piezoelectric layer; Step S4: Prepare a first micro-aperture and a second micro-aperture on the surface of the top electrode, wherein the first micro-aperture completely penetrates the top electrode having a set thickness, and the second micro-aperture does not completely penetrate the top electrode having a set thickness. Step S5: Etch a release hole to form on the outer periphery of the first micro-aperture and the second micro-aperture, the release hole extending and connecting to the sacrificial layer; Step S6: Remove the sacrificial layer in the groove through the release hole to form an air cavity.

[0017] As can be seen from the above, the bulk acoustic wave device with high power load capacity and its fabrication method provided in this application improve the power load capacity of the device by setting heat dissipation pillars to construct heat diffusion channels and optimizing heat dissipation and stress release through the first micro-aperture and the second micro-aperture. Attached Figure Description

[0018] Figure 1 A schematic diagram of a bulk acoustic wave device with high power load capability provided in an embodiment of this application; Figure 2 A schematic diagram of the top electrode structure in a bulk acoustic wave device with high power load capability provided in an embodiment of this application; Figure 3A schematic flowchart illustrating the fabrication process of a bulk acoustic wave device with high power load capability, provided in an embodiment of this application; Figure 4 This is a flowchart illustrating a method for fabricating a bulk acoustic wave device with high power load capability, as provided in an embodiment of this application.

[0019] Reference numerals: 100, substrate; 101, groove; 102, air cavity; 200, support layer; 300, functional layer; 400, heat dissipation pillar; 310, bottom electrode; 320, piezoelectric layer; 330, top electrode; 331, first micro-aperture; 332, second micro-aperture. Detailed Implementation

[0020] To better illustrate the present invention, the invention will now be described in further detail with reference to the accompanying drawings.

[0021] It should be understood that, in order to make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The components of the embodiments of this disclosure described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this disclosure provided in the accompanying drawings is not intended to limit the scope of the claimed disclosure, but merely represents selected embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0022] The following description uses at least one specific embodiment as an example. In this embodiment: Firstly, such as Figure 1 as well as Figure 2 As shown, a bulk acoustic wave device with high power load capability is provided, comprising: Substrate 100, wherein a groove 101 is formed in the substrate 100; A support layer 200 and a functional layer 300 are sequentially stacked on top of the substrate 100, and an air cavity 102 is formed between the groove 101 and the support layer 200. Heat dissipation column 400 is disposed in the air cavity 102 and embedded in the substrate 100. The heat dissipation column 400 is used to construct a heat diffusion channel for conducting heat from the functional layer 300 to the interior of the substrate 100. The functional layer 300 includes a bottom electrode 310, a piezoelectric layer 320 and a top electrode 330, which are sequentially stacked on the support layer 200 from bottom to top. The surface of the top electrode 330 is provided with at least one first micro-opening 331 corresponding to the position of the heat sink 400, and the first micro-opening 331 completely penetrates the top electrode 330 having a set thickness. The top electrode 330 surface is also provided with at least one second micro-aperture 332, the second micro-aperture 332 does not completely penetrate the top electrode 330 having a set thickness, and the opening position of the second micro-aperture 332 is located in the device stress concentration area on the surface of the top electrode 330.

[0023] This embodiment provides a bulk acoustic wave device with high power load capability, whose structural design is aimed at optimizing thermal management and stress relief.

[0024] Specifically, the device includes a substrate 100, which serves as the fundamental support structure for the bulk acoustic wave (BAW) device. The substrate 100 is typically made of materials such as silicon, glass, or ceramic, providing stable support for subsequent layered structures. The bottom electrode 310 and top electrode 330 are key components for converting electrical signals into acoustic signals. They hold a piezoelectric layer 320, and by applying an electric field, the piezoelectric layer 320 undergoes mechanical deformation, thereby exciting acoustic waves. The piezoelectric layer 320 is the core of the resonator, and its thickness determines the resonant frequency of the BAW device. The air cavity 102 is designed to provide an acoustically isolated region, reducing sound wave leakage to the substrate 100 and thus improving the performance of the BAW device.

[0025] To enhance the device's heat dissipation capability, a heat dissipation pillar 400 is also provided. This heat dissipation pillar 400 is disposed within the air cavity 102 and embedded within the substrate 100, serving to create a heat diffusion channel for heat conduction from the functional layer 300 to the interior of the substrate 100. The functional layer 300 includes a bottom electrode 310, a piezoelectric layer 320, and a top electrode 330 sequentially stacked on the support layer 200. The bottom electrode 310 and top electrode 330 are typically formed from metallic materials (such as tungsten) through processes such as sputtering or evaporation, while the piezoelectric layer 320 is formed from piezoelectric materials (such as aluminum nitride, zinc oxide, etc.) through processes such as sputtering. For example, the electrode can employ a single-layer metal structure, and the piezoelectric layer 320 can be formed using a deposition process.

[0026] At least one first micro-aperture 331 corresponding to the position of the heat sink 400 is provided on the surface of the top electrode 330. The first micro-aperture 331 completely penetrates the thickness of the top electrode 330, and the cross-sectional area of ​​the first micro-aperture 331 is larger than the cross-sectional area of ​​the second micro-aperture 332. The first micro-aperture 331 can be formed by etching a circular or square through hole above the top electrode 330, the size of which is sufficient to cover the heat sink 400 below.

[0027] In addition, at least one second micro-aperture 332 is provided on the surface of the top electrode 330. The second micro-aperture 332 does not completely penetrate the thickness of the top electrode 330. The location of the second micro-aperture 332 is situated in a stress concentration region on the surface of the top electrode 330. This stress concentration region is determined based on the fixed production parameters of the bulk acoustic wave device, such as the structural parameters, material parameters, and processing parameters of the bulk acoustic wave device. The formation of the second micro-aperture 332 can also be achieved through photolithography and etching processes, but precise control of the etching depth is required. For example, shallow circular or rectangular grooves can be etched at the edge region or corner of the top electrode 330, retaining a certain thickness of top electrode 330 material at the bottom.

[0028] The above technical solution is illustrated below with a more specific example: In traditional designs, when bulk acoustic wave (BAW) devices operate at high power, the piezoelectric layer 320 generates significant heat and mechanical stress due to the high electric field, leading to performance degradation or even device failure. To address this issue, the BAW device in this embodiment is configured as follows.

[0029] Specifically, a series of first micro-apertures 331 are provided on the surface of the top electrode 330, precisely corresponding to the positions of the heat sink 400. These first micro-apertures 331 completely penetrate the thickness of the top electrode 330, allowing direct physical and thermal contact between the top electrode 330 and the heat sink 400 below. When the top electrode 330 generates heat due to current flow, the heat can be rapidly transferred to the heat sink 400 through these first micro-apertures 331, further improving heat dissipation efficiency.

[0030] Meanwhile, to cope with the mechanical stress generated during high-power operation, at least one second micro-aperture 332 is provided on the surface of the top electrode 330 in areas of device stress concentration, such as device edges or structural abrupt changes. These second micro-apertures 332 are unique in that they do not completely penetrate the thickness of the top electrode 330, but rather retain a thin layer of the top electrode 330 material at the bottom. When the device operates at high power and stress is generated in the piezoelectric layer 320 and the electrode layer, these second micro-apertures 332 can act as stress relief points, locally absorbing and dispersing stress, preventing excessive stress concentration that could lead to device structural damage or performance drift. Because the top electrode 330 material is retained at the bottom, these micro-apertures, while releasing stress, can maintain the electrical continuity and integrity of the top electrode 330, avoiding negative impacts on the device's electrical performance.

[0031] The heat sink 400 design in this embodiment, particularly its embedding structure within the substrate 100, creates a heat diffusion channel directly from the functional layer 300 to the interior of the substrate 100. Compared to traditional cavity-type devices that rely solely on the air cavity 102 or thin film layer for heat conduction, this significantly improves the efficiency of heat transfer from the core heat-generating area to the external environment. The placement of the first micro-aperture 331 further optimizes the thermal coupling between the top electrode 330 and the heat sink 400, ensuring that heat can be rapidly transferred from the top electrode 330, the primary heat source.

[0032] In summary, the bulk acoustic wave device of this embodiment solves the problems of insufficient heat dissipation and performance degradation caused by stress concentration in high-power scenarios through integrated thermal management and stress relief structure, without sacrificing the advantages of device miniaturization or introducing significant parasitic modes. This enables the bulk acoustic wave device of this embodiment to meet the high-power processing requirements of next-generation radio frequency systems.

[0033] In this embodiment, preferably, the shape of the first micro-aperture 331 is one of plum blossom shape, semi-circle, semi-ellipse, fan shape or heart shape.

[0034] Furthermore, any edge segment on the first micro-aperture 331 is non-parallel to any edge segment of the top electrode 330, indicating that there is an angle or curve relationship between the outline of the first micro-aperture 331 and the overall boundary line of the top electrode 330. This non-parallel design helps to break the path of thermal stress propagation along a specific direction, thereby avoiding excessive stress concentration in the edge region or corner of the top electrode 330. For example, if the top electrode 330 is rectangular, the edge of the first micro-aperture 331 should not be parallel to any side of the rectangle, but rather inclined or curved.

[0035] Preferably, the number of the first micro-openings 331 is the same as the number of the heat dissipation pillars 400, and the first micro-openings 331 and the heat dissipation pillars 400 are configured in a one-to-one correspondence. Furthermore, each of the first micro-openings 331 completely covers the cross-section of the heat dissipation column 400 disposed below it.

[0036] To illustrate this, let's take a specific example, such as... Figure 1 as well as Figure 2As shown, for example, in a bulk acoustic wave device, two first micro-apertures 331 are provided on the surface of the top electrode 330, and two heat sinks 400 are correspondingly provided in the air cavity 102. During the fabrication process, high-precision photolithography and etching techniques are used to ensure that the positions of the two first micro-apertures 331 on the top electrode 330 are precisely aligned with the center positions of the two heat sinks 400 below. For example, if the cross-section of the heat sink 400 is a square with a side length of X, the corresponding first micro-aperture 331 can be designed as a square with a side length of Y (Y>X), or a circle with a diameter of D (D>X), to ensure that the opening of the first micro-aperture 331 can completely cover the entire top cross-section of the heat sink 400, so that the heat generated by the functional layer 300 can be transferred directly to the heat sink 400 below through the first micro-apertures 331 without obstruction, thereby achieving efficient heat dissipation.

[0037] In this embodiment, preferably, the shape of the second micro-aperture 332 is one of the following: teardrop shape, semi-circular shape, semi-elliptical shape, fan shape, or heart shape; Furthermore, any edge segment on the second micro-aperture 332 is non-parallel to any edge segment of the top electrode 330. This is intended to break the resonance or superposition effect that stress waves may form between parallel boundaries. When a stress wave encounters a non-parallel boundary, its propagation direction is changed, thereby preventing stress from accumulating continuously in a specific direction. For example, if the edge of the top electrode 330 is a straight line, and the edge of the second micro-aperture 332 is also parallel to the edge of the top electrode 330, the stress wave may form a standing wave between them, leading to an abnormal increase in local stress. By ensuring a non-parallel relationship, stress waves can be effectively scattered and attenuated, further enhancing the fatigue resistance and fracture resistance of the top electrode 330.

[0038] Furthermore, the bottom of the second micro-aperture 332 has a top electrode 330 material retention; and the thickness of the top electrode 330 material retention does not exceed 50 nm.

[0039] The retention of the top electrode 330 material refers to the fact that during the formation of the second micro-aperture 332, the top electrode 330 material was not completely removed, but a layer of the original top electrode 330 material was retained at the bottom of the aperture. The main function of retaining this top electrode 330 material is to maintain the structural integrity of the top electrode 330, avoiding electrical short circuits or a decrease in mechanical strength caused by complete penetration. Simultaneously, by controlling its thickness, stress relief can be achieved to a certain extent, and it may affect the propagation characteristics of sound waves.

[0040] The thickness of the retaining layer of the top electrode 330 material does not exceed 50 nm, which is used to balance stress relief, electrical performance, and mechanical strength. If the retaining layer is too thick, it may not effectively relieve stress or excessively hinder sound wave propagation; if the retaining layer is too thin, it may lead to insufficient mechanical strength or make it prone to electrical short circuits. A thickness range of no more than 50 nm is generally considered to be the effective range for achieving good stress relief and maintaining electrical isolation.

[0041] Preferably, the number of the second micro-apertures 332 is greater than or equal to 1.

[0042] In this embodiment, preferably, the heat dissipation column 400 is made of silicon nitride, graphene, or a mixture of silicon nitride and graphene.

[0043] Furthermore, the support layer 200 and the heat dissipation column 400 are made of the same material; and the support layer 200 and the heat dissipation column 400 are integrally formed.

[0044] Specifically, the fact that the support layer 200 and the heat dissipation column 400 are made of the same material means that the support layer 200 and the heat dissipation column 400 maintain consistency in material selection. For example, if the heat dissipation column 400 is made of silicon nitride, then the support layer 200 is also made of silicon nitride; if the heat dissipation column 400 is made of graphene, then the support layer 200 is also made of graphene; or both are made of a mixture of silicon nitride and graphene.

[0045] As a means of achieving this, during the manufacturing process, co-deposition or co-growth can be used to ensure that the two structures are highly similar in chemical composition and physical properties, thereby achieving the effect of using the same material and forming a single piece.

[0046] Furthermore, by designing the support layer 200 and the heat sink 400 as a single integral piece of the same material, these two key structures achieve a high degree of uniformity in material properties, such as thermal expansion coefficient, mechanical strength, and chemical stability. This material uniformity effectively avoids thermal stress concentration or mechanical stress mismatch that may occur at the interfaces of different materials, thereby enhancing the reliability and stability of the device under high-temperature or high-power operating conditions. Simultaneously, the integral manufacturing method ensures a seamless, continuous structure between the support layer 200 and the heat sink 400, eliminating interface defects or weaknesses that may exist during step-by-step manufacturing and assembly. This provides a more efficient heat conduction path, as heat can be continuously transferred from the functional layer 300 through the support layer 200 and the integrated heat sink 400 to the substrate 100, reducing thermal resistance and enhancing the overall mechanical strength of the structure.

[0047] Preferably, the cross-sectional shape of the heat dissipation column 400 is one of the following: square, rectangle, regular polygon, circle, ellipse, semicircle, semi-ellipse, fan shape, or heart shape; the cross-sectional area of ​​the heat dissipation column 400 does not exceed 20% of the surface area of ​​the top electrode 330.

[0048] The cross-sectional shape of the heat sink 400 refers to the cross-sectional profile of the heat sink 400 in the direction perpendicular to its height. Choosing different cross-sectional shapes can affect the contact area between the heat sink 400 and the surrounding material, the heat conduction path, and the etching or deposition characteristics during the manufacturing process.

[0049] Limiting the cross-sectional area of ​​the heat sink 400 to less than 20% of the surface area of ​​the top electrode 330 aims to minimize the impact of the heat sink 400 on the acoustic resonant mode between the piezoelectric layer 320 and the top electrode 330 while ensuring effective heat dissipation. If the area is too large, it may significantly alter the propagation path and reflection characteristics of the acoustic waves, leading to a decrease in Q value or a shift in the resonant frequency; if the area is too small, it may not provide sufficient heat conduction paths, thus limiting high-power load capacity. This limitation ensures a balance between heat dissipation efficiency and acoustic performance.

[0050] Secondly, such as Figure 3 and Figure 4 As shown, a method for fabricating a bulk acoustic wave device with high power load capability as described above is provided, comprising: Step S1: A groove 101 is etched into the substrate 100, a sacrificial layer is deposited within the groove 101, and planarization is performed. The groove 101 can be formed by dry etching techniques, such as reactive ion etching (RIE) or deep reactive ion etching (DRIE), or by wet etching techniques, such as anisotropic etching of the silicon substrate 100 using potassium hydroxide (KOH) solution. The formation of the groove 101 aims to provide a predetermined space for the subsequent construction of the air cavity 102. The sacrificial layer is deposited within the groove 101. This sacrificial layer can be made of a material that is easily removed selectively, such as polysilicon. The deposition method can be plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), or spin coating. The sacrificial layer serves as a temporary support structure and is removed in a subsequent step to form the air cavity 102. The planarization process can employ techniques such as chemical mechanical polishing (CMP) to ensure a smooth surface of the sacrificial layer, providing a good foundation for the growth or deposition of subsequent layers.

[0051] Step S2: Through-holes for growing the heat sink 400 are etched on the sacrificial layer. Material is filled into the through-holes, and material is simultaneously deposited on the sacrificial layer and part of the substrate 100 surface to form an integrated heat sink 400 and support layer 200, followed by planarization. The etching of the through-holes on the sacrificial layer can be achieved through a combination of photolithography and dry etching (such as RIE). The shape and position of the through-holes precisely define the geometry of the heat sink 400. Filling the through-holes with material and simultaneously depositing material on the sacrificial layer and part of the substrate 100 surface to form the integrated heat sink 400 and support layer 200 can be achieved through a single deposition process, such as chemical vapor deposition (CVD), filling the through-holes with silicon nitride, graphene, or a mixture of silicon nitride and graphene (as described in the bulk acoustic wave device above), and simultaneously forming the support layer 200 above the sacrificial layer. This integrated molding method helps to enhance the bonding strength and thermal conductivity between the heat sink 400 and the support layer 200. The subsequent planarization process can also employ techniques such as chemical mechanical polishing (CMP) to ensure a smooth surface on the integrated structure.

[0052] Step S3: A bottom electrode 310 is fabricated on the support layer 200, a piezoelectric layer 320 is deposited on the bottom electrode 310, and a top electrode 330 is fabricated on the piezoelectric layer 320. The bottom electrode 310 and top electrode 330 can be fabricated using thin-film deposition techniques such as sputtering and evaporation, combined with photolithography and etching processes to form the desired electrode pattern. The electrode material is typically a metal, such as molybdenum (Mo). The piezoelectric layer 320 can be deposited using techniques such as metal-organic chemical vapor deposition (MOCVD). Commonly used piezoelectric materials include aluminum nitride (AlN) or lead zirconate titanate (PZT).

[0053] Step S4: A first micro-aperture 331 and a second micro-aperture 332 are fabricated on the surface of the top electrode 330; wherein, the first micro-aperture 331 completely penetrates the top electrode 330 having a predetermined thickness, and the second micro-aperture 332 does not completely penetrate the top electrode 330 having a predetermined thickness; the fabrication of the first micro-aperture 331 and the second micro-aperture 332 can be achieved through photolithography and etching techniques. For the completely penetrating first micro-aperture 331, precise control of the etching time or selective etching agent can be used to ensure its complete penetration of the top electrode 330. For the partially penetrating second micro-aperture 332, the etching depth can be controlled (e.g., by adjusting the etching time) to retain a certain thickness of top electrode 330 material at its bottom.

[0054] Step S5: Etch a release hole around the first micro-aperture 331 and the second micro-aperture 332 to form a release hole. The release hole extends and connects to the sacrificial layer. The etching of the release hole can also be done using photolithography and dry etching techniques. Its position and depth can be controlled to ensure that it can extend to the sacrificial layer below and provide a channel for the subsequent removal of the sacrificial layer.

[0055] Step S6: Remove the sacrificial layer in the groove 101 through the release hole to form an air cavity 102; wherein, the removal of the sacrificial layer can be carried out by selective etching technology, such as wet etching using hydrofluoric acid (HF) vapor, so as to completely form the air cavity 102.

[0056] In summary, the bulk acoustic wave device with high power load capacity and its fabrication method provided in this embodiment achieves heat management, reduces heat accumulation, and alleviates stress concentration by setting heat dissipation pillars 400 to construct heat diffusion channels and optimizing heat dissipation and stress release through first micro-apertures 331 and second micro-apertures 332, thereby improving the power load capacity of the device.

[0057] Finally, it should be noted that the above-described embodiments are merely specific implementations of this disclosure, used to illustrate the technical solutions of this disclosure, and not to limit them. The protection scope of this disclosure is not limited thereto. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features within the scope of the technology disclosed in this disclosure. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure, and should all be covered within the protection scope of this disclosure.

Claims

1. A bulk acoustic wave device with high power load capability, characterized in that, include: A substrate in which grooves are formed; A support layer and a functional layer are sequentially stacked on top of the substrate, and an air cavity is formed between the groove and the support layer; A heat dissipation column is disposed within the air cavity and embedded within the substrate, and the heat dissipation column is used to construct a heat diffusion channel for conducting heat from the functional layer to the interior of the substrate; The functional layer includes a bottom electrode, a piezoelectric layer, and a top electrode, which are sequentially stacked on the support layer from bottom to top. The surface of the top electrode is provided with at least one first micro-opening corresponding to the position of the heat dissipation column. The first micro-opening completely penetrates the top electrode with a set thickness. Any edge segment on the first micro-opening is not parallel to any edge segment of the top electrode. The top electrode surface is also provided with at least one second micro-aperture. The second micro-aperture does not completely penetrate the top electrode with a set thickness. The second micro-aperture is located in the device stress concentration area on the surface of the top electrode. Any edge segment on the second micro-aperture is non-parallel to any edge segment of the top electrode.

2. The bulk acoustic wave device according to claim 1, characterized in that: The shape of the first micro-aperture is one of the following: plum blossom shape, semi-circle, semi-ellipse, fan shape, or heart shape.

3. The bulk acoustic wave device according to claim 1, characterized in that: The number of the first micro-openings is the same as the number of the heat dissipation pillars, and the first micro-openings are configured in a one-to-one correspondence with the heat dissipation pillars. Furthermore, each of the first micro-openings completely covers the cross-section of the corresponding heat dissipation column below it.

4. The bulk acoustic wave device according to claim 1, characterized in that: The shape of the second micro-aperture is one of the following: teardrop shape, semi-circular shape, semi-elliptical shape, fan shape, or heart shape.

5. The bulk acoustic wave device according to claim 1, characterized in that: The bottom of the second micro-aperture has a top electrode material retained; Furthermore, the thickness of the top electrode material should not exceed 50 nm.

6. The bulk acoustic wave device according to claim 1, characterized in that: The number of the second micro-apertures is greater than or equal to 1.

7. The bulk acoustic wave device according to claim 1, characterized in that: The heat dissipation column is made of silicon nitride, graphene, or a mixture of silicon nitride and graphene.

8. The bulk acoustic wave device according to claim 7, characterized in that: The support layer and the heat dissipation column are made of the same material; Furthermore, the support layer and the heat dissipation column are integrally formed.

9. The bulk acoustic wave device according to claim 1, characterized in that: The cross-sectional shape of the heat dissipation column is one of the following: square, rectangle, regular polygon, circle, ellipse, semicircle, semi-ellipse, fan shape, or heart shape. The cross-sectional area of ​​the heat dissipation column does not exceed 20% of the surface area of ​​the top electrode.

10. A method for fabricating a bulk acoustic wave device with high power load capability as described in any one of claims 1-9, characterized in that, include: Step S1: Etch a groove on the substrate, deposit a sacrificial layer in the groove, and perform planarization. Step S2: Etch through holes on the sacrificial layer to form through holes for growing heat dissipation pillars, fill the through holes with material and simultaneously deposit material on the sacrificial layer and part of the substrate surface to form an integrated heat dissipation pillar and support layer, and perform planarization treatment. Step S3: Prepare a bottom electrode on the support layer, deposit a piezoelectric layer on the bottom electrode, and prepare a top electrode on the piezoelectric layer; Step S4: Prepare a first micro-aperture and a second micro-aperture on the surface of the top electrode, wherein the first micro-aperture completely penetrates the top electrode having a set thickness, and the second micro-aperture does not completely penetrate the top electrode having a set thickness. Step S5: Etch a release hole to form on the outer periphery of the first micro-aperture and the second micro-aperture, the release hole extending and connecting to the sacrificial layer; Step S6: Remove the sacrificial layer in the groove through the release hole to form an air cavity.

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