Electrode patterning method and bulk acoustic wave resonator

Abstract

The application provides an electrode patterning method and a bulk acoustic resonator. The method comprises the following steps: after obtaining a contour line of an electrode, a boundary line segment connected with an electrode lead-out part is determined, a preset position on the boundary line segment is taken as an incident point of a transverse acoustic wave, and the whole electrode contour line is taken as a reflection boundary. On this basis, based on multiple reflection propagation of the transverse acoustic wave incident at the incident point in the contour line, a transverse acoustic wave track distributed in the contour is obtained. The density distribution of the track is used to identify an energy concentration area of a transverse mode, and then a patterning processing position is accurately determined. Through targeted patterning processing of the electrode, a resonance condition of the transverse mode is destroyed or propagation loss thereof is increased, energy leakage at a boundary and a transition defect is suppressed, and therefore a resonator Q value is improved, and filter insertion loss and selectivity are improved.

Description

Technical Field

[0001] This application relates to the field of resonator technology, and more specifically, to an electrode patterning method and a bulk acoustic resonator. Background Technology

[0002] Microelectromechanical resonators (MEMS) are widely used in wireless communication to construct filters, with bulk acoustic resonators (FBARs) being the mainstream approach. Based on the piezoelectric effect, FBARs consist of a stacked top electrode, piezoelectric layer, bottom electrode, cavity, and substrate. Acoustic waves vibrate along the thickness direction, and the resonant frequency is determined by material parameters. They can operate in the GHz band and have dimensions only at the micrometer / nanometer level, making them more suitable for device miniaturization than quartz resonators. Ideally, FBARs excite only the thickness stretching (TE) mode, effectively confining energy within the thickness direction.

[0003] However, actual devices excite transverse modes that propagate along both length and width dimensions, with their propagation direction perpendicular to the TE mode. This not only introduces additional frequency response but also leads to a decrease in the quality factor (Q). Transverse mode energy dissipates at the boundary of the central resonant region, weakening the longitudinal mode energy. Simultaneously, defects are easily generated in the transition region between the central resonant region and the connecting part during manufacturing, causing acoustic energy leakage and scattering, further degrading the Q value. An excessively low Q value directly restricts the filter's insertion loss and selectivity, hindering its application in high-performance communication systems. Summary of the Invention

[0004] The purpose of this application is to provide an electrode patterning method and a bulk acoustic resonator to address the shortcomings of the prior art.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: One aspect of this application provides an electrode patterning method, the method comprising: Obtain the outline of the electrode; Determine the boundary line segment connecting the contour line and the electrode lead-out section; Using the preset position of the boundary line segment as the incident point of the transverse sound wave and the contour line as the reflection boundary, the trajectory of the transverse sound wave distributed within the contour line is obtained. The patterned location within the contour line is determined based on the density distribution of the transverse acoustic trajectory.

[0006] Optionally, determining the patterned location within the contour line based on the density distribution of the transverse acoustic trajectory includes: Based on the density distribution of the transverse acoustic wave trajectory within the contour line, regions with a density threshold greater than the density threshold are selected as patterning locations.

[0007] Optionally, based on the density distribution of the transverse acoustic wave trajectory within the contour line, selecting regions with a density threshold as patterning locations includes: Based on the transverse acoustic wave trajectory, several intersection points formed by the mutual intersection of the transverse acoustic wave trajectories are obtained; Density-based spatial clustering is performed on several intersection points to obtain at least one point cluster. The point cluster containing more than a preset threshold of intersection points is selected as the target point cluster; The region containing the target point cluster is used as the patterned location.

[0008] Optionally, using the region containing the target point cluster as the patterned location includes: The outer convex hull of the target point cluster or the enclosing region containing the target point cluster is used as the patterned location.

[0009] Optionally, the preset position is one-third of the length of the boundary line segment.

[0010] Optionally, the transverse acoustic trajectory includes at least two non-overlapping trajectories.

[0011] Optionally, at least two non-overlapping trajectories correspond to different incident angles of transverse sound waves.

[0012] Optionally, the method further includes: Patterned structures are formed on the electrodes at patterned locations, and these patterned structures are used to reflect transverse sound waves.

[0013] Optionally, the patterned structure can be a recessed structure and / or a raised structure.

[0014] Optionally, there are multiple patterned structures, some of which are recessed structures and others are raised structures, wherein the raised structures are set near the boundary line segments.

[0015] Another aspect of this application provides a bulk acoustic resonator, comprising: Base; The bottom electrode is disposed on the substrate; A piezoelectric layer is disposed on the bottom electrode; The top electrode is disposed on the piezoelectric layer; The bottom electrode and / or top electrode are patterned using any of the electrode patterning methods described above.

[0016] The beneficial effects of this application include: This application provides an electrode patterning method and a bulk acoustic resonator. The method includes: after obtaining the outline of the electrode, first determining the boundary segment connecting the outline and the electrode lead-out portion, using a preset position on this boundary segment as the incident point of the transverse acoustic wave, and using the entire electrode outline as the reflection boundary. Based on this, the transverse acoustic wave incident at the incident point propagates through multiple reflections within the outline, obtaining transverse acoustic wave trajectories distributed within the outline. The density distribution of these trajectories is used to identify the energy concentration region of the transverse mode, thereby accurately determining the patterning processing position. By performing targeted patterning processing on the electrode, the resonance conditions of the transverse mode are disrupted or its propagation loss is increased, suppressing energy leakage at the boundary and transition defects, thereby improving the Q value of the resonator and improving the filter insertion loss and selectivity. Attached Figure Description To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic flowchart illustrating an electrode patterning method provided in an embodiment of this application; Figure 2 One of the schematic diagrams of the outline of an electrode provided in an embodiment of this application; Figure 3 A second schematic diagram of the outline of an electrode provided in an embodiment of this application; Figure 4 A third schematic diagram of the outline of an electrode provided in an embodiment of this application; Figure 5 This is the fourth schematic diagram of the outline of an electrode provided in an embodiment of this application.

[0018] Icons: 100 - outline; 110 - boundary segment; 111 - preset position; 120 - patterned position; 121 - position with the highest density distribution; 122 - position with the second highest density distribution. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In one aspect of this application, an electrode patterning method is provided, the method comprising: obtaining an electrode contour line; determining a boundary line segment connecting the contour line and the electrode lead-out portion; using a preset position of the boundary line segment as the incident point of a transverse sound wave and the contour line as the reflection boundary to obtain a transverse sound wave trajectory distributed within the contour line; and determining a patterning position within the contour line based on the density distribution of the transverse sound wave trajectory.

[0021] After obtaining the electrode contour, the boundary segment connecting the contour and the electrode lead-out is first determined. A preset position on this boundary segment is used as the incident point of the transverse acoustic wave, and the entire electrode contour is used as the reflection boundary. Based on this, the transverse acoustic wave incident at the incident point propagates through multiple reflections within the contour, resulting in transverse acoustic wave trajectories distributed within the contour. The density distribution of these trajectories is used to identify the energy concentration region of the transverse mode, thereby accurately determining the patterning processing position. By performing targeted patterning processing on the electrode, the resonance conditions of the transverse mode are disrupted or its propagation loss is increased, suppressing energy leakage at the boundary and transition defects, thereby improving the resonator Q value and enhancing the filter insertion loss and selectivity.

[0022] Figure 1 This is a flowchart illustrating an electrode patterning method provided in an embodiment of this application. The method shown in the figure includes: S100: Obtain the outline of the electrode.

[0023] Reference Figure 2 , Figure 4 and Figure 5 The shape and size of the electrode affect the propagation of transverse acoustic waves, and the electrode contour 100 is the geometric boundary of a two-dimensional closed shape of the electrode's orthographic projection along its thickness direction. Therefore, the contour 100 can effectively represent the planar shape and size of the electrode. Thus, when patterning the electrode to suppress energy leakage of transverse acoustic waves, it is necessary to obtain the electrode contour 100. This can be achieved through methods such as designing a layout or image recognition. The contour 100 defines the shape and extent of the central resonant region in the plane, serving as the spatial domain basis for subsequent analysis of the transverse acoustic wave propagation path.

[0024] It should be understood that the "electrode" used in this application as the object of transverse acoustic wave trajectory analysis and subsequent patterning can specifically correspond to various configurations in the resonator. For example, if the electrode is the top electrode of the resonator, the obtained contour line 100 is the geometric boundary of the top electrode in the plane, and the boundary line segment 110 corresponds to the junction of the top electrode and its electrode lead-out portion. As another example, if the electrode is the bottom electrode of the resonator, correspondingly, the contour line 100 is the geometric boundary of the bottom electrode, and the boundary line segment 110 is the junction of the bottom electrode and its electrode lead-out portion. In this scheme, the patterning process can be completed before the piezoelectric layer deposition. Furthermore, both the top and bottom electrodes in the resonator can be electrodes. Moreover, the electrode contour line 100 can be either the physical geometric boundary of the electrode itself, or it can coincide with or approximate the boundary of the effective resonant region of the resonator. For example, the boundary of the overlapping region of the top electrode, piezoelectric layer, and bottom electrode in the thickness direction can coincide with the electrode contour line 100.

[0025] S200: Determine the boundary line segment connecting the contour line and the electrode lead-out portion.

[0026] Reference Figure 2 On the acquired contour line 100, the boundary line segment 110 connecting the electrode and the electrode lead-out is identified and defined. The purpose of the boundary line segment 110 is to determine the incident reference position of the transverse acoustic wave. The boundary line segment 110 of the contour line 100 can be determined using several methods: for example, based on the layout data of the electrode layer and the electrode lead-out, the adjacent boundary between them can be determined, and the line segment in the electrode contour line 100 corresponding to this adjacent boundary can be defined as the boundary line segment 110; another example is that the start and end points specified or marked on the electrode contour during the design phase can be obtained, and the line connecting the start and end points can be used as the boundary line segment 110.

[0027] S300: Using the preset position of the boundary line segment as the incident point of the transverse sound wave and the contour line as the reflection boundary, the transverse sound wave trajectory distributed within the contour line is obtained.

[0028] Reference Figure 2 After the boundary segment 110 is determined, a preset position 111 on the boundary segment 110 is then determined. The preset position 111 is one or more starting points selected on the segment for emitting simulated sound waves. The selection method includes, but is not limited to: selecting a point near one end of the boundary segment 110 as a single incident point; or selecting multiple discrete incident points at equal or non-equal intervals along the boundary segment 110.

[0029] Reference Figure 2The entire electrode profile 100 is considered as a reflection boundary during the transverse propagation of sound waves: the electrode profile 100 typically corresponds to the physical edge of the electrode material, or to the interface of abrupt change in acoustic impedance between the effective resonant region and the external non-resonant region. When a transverse sound wave propagates to this boundary, due to the difference in acoustic impedance, the sound wave is reflected rather than transmitted, and the energy is confined within the region enclosed by the profile 100.

[0030] Given an incident point and a reflection boundary, a trajectory tracing method can be used to generate sound wave trajectories. Specifically, transverse sound waves originate from an incident point at a preset position 111 at a preset angle. Each sound ray propagates in a straight line, and upon reaching the boundary of the contour line 100, it is reflected according to the law of reflection (the incident angle equals the reflection angle), continuing to propagate within the contour line 100. After multiple reflections, a zigzag propagation trajectory is formed. The geometric distribution of these trajectories directly reflects the possible energy propagation path and spatial coverage of the transverse sound waves incident from this boundary within the resonant region.

[0031] It should be understood that the trajectory of the transverse acoustic wave in this application is a trajectory of finite reflections. This is based on the fact that in a real resonator, each time the transverse acoustic wave is reflected by the electrode contour boundary, some energy is lost due to acoustic wave scattering, boundary roughness, intrinsic material damping, and leakage to the external structure. The more reflections, the weaker the energy becomes, and the contribution of the trajectory of higher-order reflections to the overall energy distribution is negligible. Therefore, the trajectory of the transverse acoustic wave is a trajectory of finite reflections, which can reduce the power consumption and difficulty of data processing. It also facilitates that the subsequent patterning position 120 is located on the path where the transverse mode energy is concentrated, thereby achieving a targeted suppression effect on the transverse mode with a smaller computational cost.

[0032] by Figure 2 For example, the figure shows the trajectory distribution of the first transverse wave after it is incident from the preset position 111 of the boundary line segment 110 and undergoes 6 reflections. At the same time, it also shows the trajectory distribution of the second transverse wave after it is incident from the preset position 111 of the boundary line segment 110 and undergoes 4 reflections.

[0033] The density distribution of the transverse acoustic wave trajectory within the contour line 100 can characterize the energy distribution of the transverse modes: by simulating the multiple reflections of the transverse acoustic wave after it enters the resonant region from the weak boundary region, it can clearly reveal where the energy gathers and where it frequently crosses within the contour, providing a precise spatial coordinate basis for determining the patterned position 120 based on the trajectory density in the next step.

[0034] S400: Determines the patterned position within the contour line based on the density distribution of the transverse acoustic trajectory.

[0035] After obtaining the transverse acoustic wave trajectories distributed within the contour line 100, the spatial distribution of the trajectory density can be obtained. Regions with higher density indicate a greater probability of being repeatedly traversed by transverse acoustic waves, and are key locations where transverse modal energy converges in the resonant region, forming standing wave antinodes or enhancing interference. This provides spatial coordinates for determining the subsequent patterning position 120.

[0036] The patterning position 120 is determined based on the trajectory density distribution. For example, the patterning position 120 can be defined as the path and region where the transverse mode energy is most concentrated, thereby disrupting its resonance condition or enhancing its propagation loss from the source. This prevents the transverse mode from forming an effective energy accumulation and leakage channel, thus confining the energy more effectively in the longitudinal (TE) mode. This not only suppresses the additional frequency response but also directly improves the Q value of the resonator, thereby improving key performance indicators of the filter such as insertion loss, selectivity, and in-band flatness.

[0037] Optionally, in S400, determining the patterned position 120 within the contour line 100 based on the density distribution of the transverse acoustic trajectory includes: S410: Based on the density distribution of the transverse acoustic wave trajectory within the contour line, select regions with a density threshold as patterning locations.

[0038] After obtaining the density distribution of the transverse acoustic wave trajectory, a density threshold is preset as a screening criterion. This density threshold can be set according to the desired suppression effect, such as taking a certain percentage of the maximum density, the average of all density values, or an absolute value calibrated based on experimental or simulation data. Regions with density higher than this threshold indicate that transverse acoustic wave energy is highly concentrated and repeatedly crosses through these areas, making them key nodes for the formation of standing wave antinodes or interference enhancement in transverse modes; while regions with density lower than the threshold mean that only a few trajectories pass through, and the energy is relatively sparse.

[0039] Reference Figures 2 to 5 By defining the region above the density threshold as the patterning location 120, the energy hotspots that dominate the transverse mode can be precisely patterned, thereby achieving a targeted transverse mode suppression effect with the minimum patterning area and the lowest effective electrode area loss.

[0040] Optionally, the number of patterned locations 120 defined within the outline 100 can be one or more. Specifically, for example... Figure 2 In the example, the position 121 with the highest density distribution is used as the patterning position 120; for another example... Figure 3 In the process, the position 121 with the largest density distribution and the position 122 with the second largest density distribution are used as patterning positions 120.

[0041] Optionally, in S410, selecting a region with a density greater than a density threshold as the patterning location 120 based on the density distribution of the transverse acoustic wave trajectory within the contour line 100 includes: S411: Based on the transverse acoustic wave trajectory, obtain several intersection points formed by the mutual intersection of transverse acoustic wave trajectories.

[0042] Reference Figures 2 to 5 After obtaining the transverse sound wave trajectories formed by multiple reflections within the contour line 100, it is possible to determine the intersection points formed by the spatial intersection of one, any two, or more trajectories. These intersection points can reflect the spatial locations where energy accumulates in the resonant region for transverse sound waves with different propagation paths. The intersection points can also more directly capture the locations where interference coupling easily occurs between multiple reflected sound waves.

[0043] S412: Perform density-based spatial clustering on several intersection points to obtain at least one point cluster.

[0044] Reference Figures 2 to 5 After obtaining a large number of spatially distributed discrete intersection points, a density-based clustering algorithm is used to group these intersection points. This algorithm, based on a preset spatial neighborhood radius and a minimum number of points within the neighborhood threshold, groups spatially adjacent and densely distributed intersection points into the same cluster, while excluding isolated and sparsely distributed outliers. In particular, energy hotspots in lateral modes are often defined by a group of spatially tightly clustered intersection points; density clustering can effectively identify the spatial boundaries of these regions, transforming discrete sets of intersection points into continuous regional targets.

[0045] S413: Select the point cluster containing more than a preset threshold as the target point cluster.

[0046] Each obtained point cluster is screened, and the number of intersections within each cluster is counted and compared with a preset threshold. Point clusters with more than the threshold indicate that the region is an intersection aggregation area, corresponding to the dominant region of transverse mode energy; while point clusters with fewer intersections may only correspond to local weak interference points or numerical noise. Through threshold screening, regions that play a key role in transverse modes are retained, while secondary or insignificant aggregation areas are filtered out, ensuring that subsequent patterning processing focuses on energy aggregation locations.

[0047] S414: Use the region where the target point cluster is located as the patterned location.

[0048] Reference Figures 2 to 5The spatial coverage of the target point clusters filtered by the threshold is directly determined as the patterning location on the electrode. This region corresponds to the part where the transverse acoustic wave energy is highly concentrated and the interference effect is strongest. Patterning processes such as slotting, opening, and forming protrusions in this region can precisely destroy the standing wave antinodes or energy circulation paths of the transverse modes, achieving the best transverse mode suppression effect with the smallest processing area, while preserving the effective working area of ​​the electrode as much as possible, taking into account both the electrical and acoustic performance of the resonator.

[0049] Optionally, using the region where the target point cluster is located as the patterned location 120 includes using the outer convex hull of the target point cluster or the enclosing region containing the target point cluster as the patterned location 120.

[0050] In practice, the convex hull of the target point cluster, the minimum circumscribed geometry (rectangle, circle, etc.), or the region formed by extending the boundary of the point cluster outward by a certain margin can be used as the geometric definition of the patterned position 120.

[0051] Optionally, the preset position 111 is located at 1 / 3 of the length of the boundary segment 110. (Refer to...) Figures 2 to 5 The boundary segment 110 has two endpoints, wherein one-third of the length of the boundary segment 110 includes two positions close to each of the two endpoints. Therefore, at least one of these positions can be used as a preset position 111.

[0052] Optionally, boundary segment 110 is a straight line segment.

[0053] Optionally, the transverse acoustic trajectory includes at least two non-overlapping trajectories.

[0054] Each trajectory corresponds to one transverse acoustic wave. Therefore, at least two non-overlapping trajectories can correspond to multiple transverse acoustic waves. This allows for the coverage of a wider area within the contour through multiple transverse acoustic wave trajectories, making the trajectory density distribution and intersection analysis highly representative and facilitating the accurate identification of the location where transverse modal energy converges.

[0055] Optionally, at least two non-overlapping trajectories correspond to different incident angles of transverse sound waves.

[0056] Different incident angles refer to the fact that at the incident point of the predetermined position 111 of the boundary line segment 110, each sound ray is incident at a different incident angle relative to the boundary normal direction of that point. Since the incident angle directly determines the initial propagation direction of the sound wave after entering the resonant region, different incident angles will cause the sound wave to undergo different reflections and spatial paths, thus forming non-overlapping trajectories.

[0057] Optionally, the method further includes forming a patterned structure on the electrode at a patterned position 120, the patterned structure being used to reflect transverse acoustic waves.

[0058] Reference Figures 2 to 5 After determining the patterning positions 120, the metal layer required for the electrode can be fabricated first. Then, the electrode is formed on the metal layer using semiconductor technology that includes a patterning process, and simultaneously, a patterned structure at each patterning position 120 is formed on the electrode. Alternatively, the electrode can be fabricated first, and then a patterned structure at each patterning position 120 can be formed on the electrode using semiconductor technology that includes a patterning process.

[0059] Patterned structures can actively construct reflective interfaces along the propagation path of transverse sound waves by utilizing the principle of acoustic impedance mismatch. When a transverse sound wave propagates to the patterned structure, the sound wave is reflected and its propagation direction is changed due to the geometrical abrupt change or material property difference introduced by the structure, thereby blocking its original resonant cycle path and suppressing the formation of standing waves or energy accumulation. The specific shape, size, and arrangement of the patterned structure can be specifically designed according to the wavelength and incident direction of the transverse sound wave to be reflected, such as forming a Bragg reflector grating or other phononic crystal structures to achieve efficient selective reflection of specific frequency transverse modes.

[0060] Optionally, the patterned structure can be a recessed structure and / or a raised structure.

[0061] A recessed structure refers to a structure formed by removing part of the material from the electrode surface or through the thickness of the electrode, including but not limited to blind grooves, through grooves, circular holes, rectangular windows or other pits of any shape.

[0062] Raised structures refer to additional structures formed on the original surface of the electrode through material deposition or growth, including but not limited to strip-shaped raised ridges, columnar raised points, annular raised platforms or other raised contours.

[0063] The recessed and raised structures can be used individually or in combination on the same electrode. For example, a recessed structure can be set at one patterned location 120, and a raised structure can be set at another patterned location 120, or a composite recessed and raised structure can be formed at the same location. Both structures can effectively introduce abrupt changes in acoustic impedance boundaries within the electrode plane, generating a reflection effect on transverse acoustic waves propagating along the electrode layer. Both are compatible with standard micro / nano fabrication processes such as thin film deposition, photolithography, etching, and lift-off, offering high process feasibility.

[0064] Optionally, the patterned structures can be multiple, with some patterned structures being recessed and others being raised, wherein the raised structures are positioned close to the boundary line segment 110. This is more conducive to the suppression of transverse sound waves.

[0065] For ease of understanding, the following description will use the outline 100 of a portion of the electrodes as an example: Example 1 Please refer to Figure 2 The diagram shows the outline 100 of the electrode, which is an asymmetrical quadrilateral. The straight line on the left side of the outline 100 serves as the boundary segment 110. A preset position 111 is defined as the point approximately one-third of the way down from the lower end of the boundary segment 110; this position is the incident point for two transverse sound waves with different incident angles (the first transverse wave and the second transverse wave, respectively). The first transverse wave forms its trajectory after six reflections, and the second transverse wave forms its trajectory after four reflections. Figure 2 The trajectory shown can be used to obtain the density distribution of the trajectory within the contour line 100. The densest region (i.e., the position 121 with the largest density distribution) is the area enclosed by the trajectory, which is used as the patterned position 120, and a patterned structure is formed here.

[0066] Example 2 Please refer to Figure 3 The difference from Example 1 is that not only is the densest region (position 121 with the highest density distribution) used as patterned position 120, but also the second densest region (position 122 with the second highest density distribution) is used as patterned position 120.

[0067] Example 3 Please refer to Figure 4 The diagram shows the outline 100 of the electrode, which is an asymmetrical teardrop shape. The straight line on the left side of the outline 100 serves as the boundary segment 110. A preset position 111 is defined as the point approximately one-third of the way down from the lower end of the boundary segment 110; this position is the incident point for two transverse sound waves with different incident angles (the first transverse wave and the second transverse wave, respectively). The first transverse wave forms its trajectory after three reflections, and the second transverse wave forms its trajectory after three reflections. Figure 4 The trajectory shown can be used to obtain the density distribution of the trajectory within the contour line 100. The densest region (i.e., the position 121 with the largest density distribution) is the area enclosed by the trajectory, which is used as the patterned position 120, and a patterned structure is formed here.

[0068] Example 4 Please refer to Figure 5 The diagram shows the outline 100 of the electrode, which is elliptical in shape. The straight edge approximately to the left of the outline 100 is designated as boundary segment 110. A preset position 111 is defined as the point approximately one-third of the way down from the lower end of boundary segment 110; this position is the incident point for two transverse sound waves with different incident angles (the first transverse wave and the second transverse wave, respectively). The first transverse wave forms its trajectory after seven reflections, and the second transverse wave forms its trajectory after four reflections. Figure 5The trajectory shown can be used to obtain the density distribution of the trajectory within the contour line 100. The densest region (i.e., the position 121 with the largest density distribution) is the area enclosed by the trajectory, which is used as the patterned position 120, and a patterned structure is formed here.

[0069] Another aspect of this application provides a bulk acoustic resonator, comprising: Base; The bottom electrode is disposed on the substrate; A piezoelectric layer is disposed on the bottom electrode; The top electrode is disposed on the piezoelectric layer; The bottom electrode and / or top electrode are patterned using any of the electrode patterning methods described above.

[0070] The resulting bulk acoustic resonator, due to the patterned position 120 and the structural design, prevents the transverse modes from forming effective energy accumulation and leakage channels, thus confining the energy more effectively within the longitudinal (TE) modes. This not only suppresses additional frequency responses but also directly improves the resonator's Q value, thereby enhancing key performance indicators such as insertion loss, selectivity, and in-band flatness of the filter.

[0071] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0072] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0073] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0074] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0075] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An electrode patterning method, characterized in that, The method includes: Obtain the outline of the electrode; Determine the boundary line segment connecting the contour line and the electrode lead-out portion; Using the preset position of the boundary line segment as the incident point of the transverse sound wave and the contour line as the reflection boundary, the transverse sound wave trajectory distributed within the contour line is obtained. The patterned position within the contour line is determined based on the density distribution of the transverse acoustic trajectory.

2. The electrode patterning method as described in claim 1, characterized in that, Determining the patterned position within the contour line based on the density distribution of the transverse acoustic trajectory includes: Based on the density distribution of the transverse acoustic wave trajectory within the contour line, a region greater than the density threshold is selected as the patterning position.

3. The electrode patterning method as described in claim 2, characterized in that, The step of selecting a region with a density threshold as the patterning location based on the density distribution of the transverse acoustic wave trajectory within the contour line includes: Based on the transverse acoustic wave trajectory, several intersection points are obtained where the transverse acoustic wave trajectories intersect each other. Density-based spatial clustering is performed on several of the intersection points to obtain at least one point cluster; The point cluster containing more than a preset threshold of intersection points is selected as the target point cluster; The region where the target point cluster is located is taken as the patterned location.

4. The electrode patterning method as described in claim 3, characterized in that, The step of using the region where the target point cluster is located as the patterned location includes: The outer convex hull of the target point cluster or the enclosing region containing the target point cluster is used as the patterned location.

5. The electrode patterning method according to any one of claims 1 to 4, characterized in that, The preset position is at 1 / 3 of the length of the boundary line segment.

6. The electrode patterning method according to any one of claims 1 to 4, characterized in that, The transverse acoustic trajectory includes at least two non-overlapping trajectories.

7. The electrode patterning method according to any one of claims 1 to 4, characterized in that, The method further includes: A patterned structure is formed on the electrode at the patterned location, the patterned structure being used to reflect transverse sound waves.

8. The electrode patterning method as described in claim 7, characterized in that, The patterned structure is a recessed structure and / or a raised structure.

9. The electrode patterning method as described in claim 8, characterized in that, The patterned structures are multiple in number, some of which are recessed structures and others are raised structures, wherein the raised structures are located close to the boundary line segments.

10. A bulk acoustic resonator, characterized in that, include: Base; The bottom electrode is disposed on the substrate; A piezoelectric layer is disposed on the bottom electrode; The top electrode is disposed on the piezoelectric layer; The bottom electrode and / or the top electrode are patterned using the electrode patterning method as described in any one of claims 1 to 9.

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