Resonator and assembly, filter, electronic device, and manufacturing method, sealing structure

Abstract

This application discloses a resonator and assembly, filter, electronic device, and fabrication method, sealing structure, the bulk acoustic resonator includes a substrate, a first electrode with an acoustic reflection structure between the substrate, and a second electrode with a piezoelectric layer between the first electrode, in a direction perpendicular to the substrate, the overlapping area of ​​the acoustic reflection structure, the first electrode, the piezoelectric layer, and the second electrode constitutes an effective area, the resonator has a ring-shaped effective area, an arbitrary point on the inner edge of the effective area is point A, the distance from point A to the center point of the resonator is D, the shortest distance from point A to the outer edge of the effective area is W, and 0.1≦W / D≦10. Adjusting the distance W in the resonator improves the heat dissipation efficiency of the resonator.

Description

[Technical field]

[0001] The present invention relates to the field of semiconductors, and more particularly to a resonator and assembly, a filter, an electronic device, and a manufacturing method and a sealing structure. This application claims priority to a Chinese patent application filed with the China Patent Office on April 6, 2023, bearing application number 202310402705.5 and entitled "Resonator and assembly, a filter, an electronic device, and a manufacturing method and a sealing structure", the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Currently, the thickness of the main functional layers of the resonator, i.e., the piezoelectric layer and the electrodes, is only at the micron or nanometer level, which makes it easy for heat to accumulate in the functional layers, resulting in negative effects such as frequency drift of the resonator, or causing and accelerating the aging and damage of the main functional layers, affecting the reliability and lifespan of the resonator, while at the same time limiting the further increase of the power capacity of the resonator. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, how to improve the heat dissipation capability of the resonator is a technical problem that needs to be solved. [Means for solving the problem]

[0004] In view of this, according to one aspect of the present application, there is provided a bulk acoustic resonator, the resonator comprising: A substrate; a first electrode having an acoustic reflection structure between the first electrode and a substrate; a second electrode with a piezoelectric layer between the first electrode and the second electrode; In a direction perpendicular to the substrate, an overlapping area of ​​the acoustic reflection structure, the first electrode, the piezoelectric layer, and the second electrode constitutes an effective area, and the resonator has a ring-shaped effective area; An arbitrary point on the inner edge of the effective area is defined as point A, the distance from point A to the center point of the resonator is defined as D, and the shortest distance from point A to the outer edge of the effective area is defined as W, where 0.1≦W / D≦10.

[0005] Preferably, in the above bulk acoustic resonator, a non-effective area is provided inside an inner edge of the effective area, the area of ​​the effective area is S1, the area of ​​the non-effective area is S2, and the relationship between S1 and S2 satisfies the following formula (1). 0.2≦S1 / S2≦12 (1)

[0006] Preferably, in the above-mentioned bulk acoustic resonator, the shortest distances from the plurality of points A to the outer edges of the effective area correspond to a plurality of Ws, the plurality of Ws have maximum and minimum values, and the ratio of the maximum value to the minimum value is 1.5:1.

[0007] Preferably, in the above bulk acoustic resonator, the arbitrary value of W can range from 10 μm to 50 μm.

[0008] Preferably, in the bulk acoustic resonator, at least one of the acoustic reflection structure, the piezoelectric layer, the first electrode and the second electrode is of an annular structure so as to form a ring-shaped effective area in a direction perpendicular to the substrate.

[0009] Preferably, in the above bulk acoustic resonator, the acoustic wave reflecting structure is located on the upper surface of the substrate or is fitted inside the substrate.

[0010] Preferably, in the above bulk acoustic resonator, the height of the acoustic wave reflecting structure is in the range of 0.1 μm to 0.5 μm.

[0011] Preferably, in the above bulk acoustic resonator, there is a dielectric block in a central region of the sound wave reflecting structure, the dielectric block being located in the non-effective region, and the sound wave reflecting structure forms a ring-shaped structure with the dielectric block.

[0012] Preferably, in the above-mentioned bulk acoustic resonator, the dielectric block includes a hollow structure, a first release passage is installed at the bottom of the hollow structure, and the first release passage penetrates the bottom of the hollow structure in a direction parallel to the substrate.

[0013] Preferably, in the above bulk acoustic resonator, the dielectric block includes a solid structure, a second release passage is provided on a sidewall of the solid structure, and the second release passage penetrates the solid structure in a direction perpendicular to the substrate.

[0014] Preferably, in the above bulk acoustic resonator, there is a gap between the piezoelectric layer and the second electrode and / or between the substrate and the first electrode in a direction perpendicular to the substrate, the gap being located in the non-effective region.

[0015] Preferably, in the above bulk acoustic resonator, an upper surface of the first electrode and / or an upper surface of the piezoelectric layer has a first recess, and a first gap is formed between at least one of the first recesses and the second electrode.

[0016] Preferably, in the above bulk acoustic resonator, the first electrode, or the first electrode and the piezoelectric layer, are recessed downward to form a second recess, and a second gap is formed between at least one of the second recesses and the second electrode.

[0017] According to a second aspect of the present application, there is provided a resonator assembly, comprising a bulk acoustic resonator as defined in any of the above, the bulk acoustic resonator being electrically connected to at least one electrical structure, the electrical structure being located in a non-active region.

[0018] According to a third aspect of the present application, there is provided a sealing structure based on any one of the bulk acoustic resonators described above, wherein a sealing film is disposed above the resonator, the sealing film seals the effective area, and a gap between the effective area and the sealing film is sound-insulated.

[0019] Preferably, in the above sealing structure, the sealing film and the non-effective area are directly connected to each other, or a support is provided between the sealing film and the non-effective area.

[0020] Preferably, in the above sealing structure, the support portion includes a metal pillar, the bottom of the metal pillar is electrically connected to the first electrode or the second electrode, and the top of the metal pillar is exposed to the outside of the sealing film and electrically connected to the outside world.

[0021] According to a fourth aspect of the present application, there is provided a filter, comprising a resonator as defined in any one of the above.

[0022] According to a fifth aspect of the present application, there is provided an electronic device, comprising any of the resonators described above.

[0023] According to a sixth aspect of the present application, there is provided a method of fabricating a bulk acoustic resonator, the method comprising the steps of: Providing a substrate; forming an acoustic reflection structure on the substrate; sequentially forming a first electrode, a piezoelectric layer, and a second electrode on the substrate and the acoustic reflection structure; In a direction perpendicular to the substrate, an overlapping area of ​​the acoustic reflection structure, the first electrode, the piezoelectric layer, and the second electrode constitutes an effective area, and the resonator has a ring-shaped effective area; An arbitrary point on the inner edge of the effective area is point A, the distance from point A to the center point of the resonator is D, and the shortest distance from point A to the outer edge of the effective area is W, where 0.1≦W / D≦10.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The bulk acoustic resonator has a ring-shaped effective area, which improves the heat dissipation efficiency of the resonator and makes the temperature of the resonator basically constant when the resonator is in operation. In addition, an arbitrary point on the inner edge of the effective area is defined as point A, the distance from point A to the center of the resonator is defined as D, and the shortest distance from point A to the outer edge of the effective area is defined as W. According to the needs of the frequency and power tolerance of the resonator, the distance W is adjusted so that W and D satisfy the relationship of 0.1≦W / D≦10, which ensures that the resonator still has good heat dissipation efficiency and more stable performance under the condition of high frequency and high power tolerance. [Brief description of the drawings]

[0025] In order to more clearly explain the technical solutions in the embodiments of the present application or the related art, the following briefly introduces drawings necessary for the description of the embodiments or the prior art. Obviously, the drawings in the following description are the embodiments of the present application, and those skilled in the art may obtain other drawings according to the drawings provided under the premise of not making any effort that amounts to inventive step. The structures, proportions, sizes, etc. shown in the drawings of this specification are all intended to facilitate understanding and reading by those skilled in the art in accordance with the contents disclosed in the specification, and are not intended to limit the conditions under which this application is implemented, and therefore have no substantial technical meaning. Any modification of the structure, change in proportionality, or adjustment of size is within the scope of the technical content disclosed in this application as long as it does not affect the effects produced by and the purpose achieved by this application. [Figure 1] FIG. 2 is a schematic diagram showing the structure of an air-gap resonator. [Diagram 2] 1 is a cross-sectional view of a bulk acoustic resonator provided by an embodiment of the present application. [Diagram 3] FIG. 3 is a plan view of the bulk acoustic resonator shown in FIG. [Figure 4] FIG. 13 is a diagram showing the results of thermodynamic emulation of a conventional sandwich-structure resonator. [Diagram 5] FIG. 13 is a diagram showing the thermodynamic emulation results of a resonator provided by another embodiment of the present application. [Figure 6]FIG. 13 shows the thermodynamic emulation results of another conventional sandwich-structure resonator. [Figure 7] FIG. 13 is a diagram showing the thermodynamic emulation results of a resonator provided by another embodiment of the present application. [Figure 8] FIG. 2 is a plan view of an acoustic reflection structure of a resonator provided by another embodiment of the present application. [Figure 9] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 10] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 11] FIG. 2 is a plan view of an acoustic reflection structure of a resonator provided by another embodiment of the present application. [Figure 12] 12 is a cross-sectional view of the sound wave reflecting structure shown in FIG. 11 in the VV′ direction. [Figure 13] FIG. 2 is a plan view of an acoustic reflection structure of a resonator provided by another embodiment of the present application. [Figure 14] 14 is a cross-sectional view of the resonator shown in FIG. 13 in the BB' direction. [Figure 15] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 16] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 17] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 18] 2 is a cross-sectional view of a resonator provided by another embodiment of the present application; [Figure 19] FIG. 2 is a plan view of a resonator assembly provided by another embodiment of the present application. [Figure 20] 20 is a cross-sectional view of the resonator assembly shown in FIG. 19 taken along the CC′ direction. [Figure 21] FIG. 2 is a cross-sectional view of a sealing structure for a resonator provided by another embodiment of the present application. [Figure 22] FIG. 2 is a cross-sectional view of a sealing structure for a resonator provided by another embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are all within the scope of protection of the present application.

[0027] 2. Description of the Related Art Film bulk acoustic resonators (Fbars) play an important role in the field of communications due to their excellent properties such as small size, high resonant frequency, high quality factor, and large power capacity.

[0028] Fig. 1 is a structural schematic diagram of an air-gap resonator, and the resonator as shown in Fig. 1 includes a substrate 101', an acoustic reflection structure 102', a first electrode 103', a second electrode 105', and a piezoelectric layer 104' located between the two electrodes. The two electrodes are also called excitation electrodes, and their function is to induce mechanical vibration of the piezoelectric layer 104', and the acoustic reflection structure 102' forms acoustic insulation between the first electrode 103' and the substrate 101' to prevent the acoustic wave from being conducted out of the resonator and causing energy loss.

[0029] Referring to FIG. 1, in an ideal state, the resonator converts only between mechanical energy and electrical energy, but in a practical situation, a part of the electrical energy and bulk acoustic waves in the device will inevitably be converted into thermal energy, and the higher the power of the resonator, the more significant the heat generation effect. In FIG. 1, the heat transfer path is indicated by the dashed arrow, and since air is a poor thermal conductor, the resonator mainly transfers heat to a part of the substrate 101' near the device through the electrodes and the piezoelectric layer 104', and the part of the substrate 101' further transfers heat to the entire substrate 101' for heat dissipation. Since the central region I of the resonator is far from the substrate 101', heat is likely to accumulate in the central region I, which affects the performance of the resonator. Therefore, how to improve the heat dissipation ability of the resonator is a technical problem that needs to be solved.

[0030] Based on the above problems, this application provides a resonator and assembly, a filter, an electronic device, a manufacturing method, and a sealing structure, in which the resonator has a ring-shaped effective area, so that the temperature can be kept basically constant in the working state and the heat dissipation efficiency can be high. If an arbitrary point on the inner edge of the effective area is point A, the distance from point A to the center point of the resonator is D, and the shortest distance from point A to the outer edge of the effective area is W, and on the premise that 0.1≦W / D≦10 is satisfied, the distance W can be adjusted according to the frequency and power allowance needs of the resonator to ensure the heat dissipation efficiency.

[0031] In order to make the above objectives, features and advantages of the present application clearer and easier to understand, the present application will be further described in detail below in combination with drawings and specific embodiments.

[0032] FIG. 2 is a cross-sectional view of a bulk acoustic resonator provided by an embodiment of the present application, and FIG. 3 is a plan view of the bulk acoustic resonator shown in FIG. 2. Referring to FIGS. 2 and 3, the resonator provided by this embodiment includes a substrate 101, a first electrode 103, a piezoelectric layer 104, a second electrode 105, and an acoustic reflection structure 102, and has an effective area A1 in a direction perpendicular to the substrate 101, and the effective area A1 is an overlapping area of ​​the acoustic reflection structure 102, the first electrode 103, the piezoelectric layer 104, and the second electrode 105, an arbitrary point on the inner edge of the effective area A1 is point A, the distance from point A to the center point O of the resonator is D, and the shortest distance from point A to the outer edge (edge ​​far from the center point) of the effective area A1 is W, and 0.1≦W / D≦10. The sound wave reflecting structure 102 is a cavity 1021 or a Bragg reflecting layer, and in this embodiment, the sound wave reflecting structure 102 is a cavity 1021. In some embodiments, a cross section can be made in any direction parallel to the substrate 101, and a point A and a center point O are identified from the cross section, and the shapes of the inner edge and the outer edge of the effective area A1 are the same or different, and the shapes include, but are not limited to, a circle, an ellipse, a regular polygon with each angle exceeding 90°, an irregular polygon with each angle exceeding 90°, and an irregular shape, and in some embodiments, the ring-shaped effective area is preferably an irregular polygon with each angle exceeding 90°, and the shapes of the inner edge and the outer edge are the same, which can effectively reduce the leakage of sound waves and improve the parallel resonance frequency (Rp). In this embodiment, the effective area A1 is approximately a pentagonal ring-shaped as an example, and the inner edge and the outer edge of the effective area A1 are in the area of ​​the parallel parts facing each other, and W is the same. The center point O is specified by the shape of the inner edge of the effective area A1. For a shape that has a geometric center, the geometric center is the center point O. For a shape whose geometric center is difficult to identify, the calculation can be assisted by computer software, such as some ordinary drawing software AUTO CAD, or the coordinates can be established and found by calculus. If the electrode shape of the resonator is an irregular pentagon formed by cutting the corners, the geometric center can be specified after restoring the cut corners.

[0033] In actual production and design, it is also possible to calculate W by adopting an arbitrary point in the central region within the region surrounded by the effective region A1, in which case the central region is a region with a relatively small area.

[0034] The resonator has a ring-shaped effective area A1, so that the temperature can be kept basically constant during operation and the heat dissipation efficiency can be high. Similar to the heat dissipation route of a traditional resonator, the resonator also transfers heat from the inside of the effective resonance area to the edge to achieve the heat dissipation effect. In the embodiment of the present application, the distance W between the inner edge and the outer edge of the effective area A1 is reduced, so that the path length of the heat transfer from the position of 1 / 2W (heat storage area) to the area outside the inner edge or the outer edge is shorter, thus avoiding the situation where a large amount of heat is concentrated in the effective resonance area and cannot be dissipated, which affects the performance of the resonator.

[0035] In the resonator of the embodiment of the present application, a ring-shaped effective area A1 is formed, which can improve the heat dissipation efficiency, and the heat dissipation effect is more obvious for the low and mid-frequency resonators and the high-frequency resonators.

[0036] 4 and 5, FIG. 4 is a thermodynamic emulation result diagram of a resonator with a normal sandwich structure, and FIG. 5 is a thermodynamic emulation result diagram of a resonator provided by another embodiment of the present application, where the resonator with a normal sandwich structure has the same effective area as the resonator in another embodiment of the present application, and the resonator frequency is the same (medium-low frequency 2.5GHZ). As can be seen from the thermal arrangement of the normal sandwich structure in FIG. 4, the thermal arrangement of the normal sandwich structure is non-uniform, the temperature is higher closer to the central region of the resonator, and heat is accumulated in the central region, with the maximum temperature reaching 40.3°C. Compared with the normal sandwich structure, the thermal arrangement of the resonator in another embodiment of the present application in FIG. 5 is more uniform, and the maximum temperature is only 26.9°C, a difference of 13.4°C, which is more efficient at dissipating heat than the normal sandwich structure.

[0037] 6 and 7, FIG. 6 is a thermodynamic emulation result diagram of another ordinary sandwich structure resonator, and FIG. 7 is a thermodynamic emulation result diagram of a resonator provided by another embodiment of the present application, in which the effective area of ​​the other ordinary sandwich structure resonator is equal to that of the resonator of another embodiment of the present application, and the frequency of the resonator is equal (high frequency 6GHZ). The maximum temperature of the center point of the ordinary sandwich structure in FIG. 6 reaches 163°C. The maximum temperature of the resonator of another embodiment of the present application shown in FIG. 7 is only 53.5°C, and in the high frequency state, its temperature distribution is still relatively uniform, and there is no obvious heat accumulation. When the resonator works in the high frequency state, the thickness of the functional layer is thinner, so the heat dissipation efficiency is lower, and the heat change is more obvious, decreasing from 163°C to 53.5°C, the difference reaches 109.5°C, and the functional layer includes a piezoelectric layer 104, a first electrode 103, and a second electrode 105.

[0038] In each embodiment of the present application, the heat dissipation effect of the resonator is good, and in particular, the high frequency resonator manufactured with this structure can ensure that the operating temperature is constant at room temperature or a slightly higher temperature for a long period of time, thereby increasing its operating lifetime. In addition, the shape of the effective area of ​​the resonator is designed to be ring-shaped, which makes it easier to flexibly adjust the effective area. This is because, when the area of ​​a single resonator is large in a traditional high frequency structure, the first electrode 103, the second electrode 105, and the piezoelectric layer 104 are thin, so that the film layer is easily distorted due to stress, which causes reliability problems in both high and low temperature operating environments and leads to device failure. When the resonator is designed to be ring-shaped, the distance W from the inner edge to the outer edge of the resonator is small, which ensures better mechanical support and heat dissipation performance, thereby making it possible to flexibly adjust the effective area of ​​the resonator.

[0039] As can be seen based on the resonator of the above embodiment, in the direction parallel to the substrate 101, the distance from the inner edge to the outer edge of the effective area A1 is W, the distance from the center point O of the resonator to the inner edge of the effective area A1 is D, and W and D satisfy the relationship of 0.1≦W / D≦10. By setting the value of W / D of the resonator to be within the range of 0.1 to 10, a better heat dissipation effect can be obtained, and the value of W / D is negatively correlated with the heat dissipation efficiency required for the resonator, and the smaller the value of W / D, the smaller the distance from the heat concentration area of ​​the effective area A1 to the edge of the effective area A1, and the higher the heat dissipation efficiency. The frequency of the resonator is positively correlated with the required heat dissipation efficiency, that is, the higher the frequency, the higher the generated heat and the higher the required heat dissipation efficiency, in this case, the smaller the value of W / D. For low-medium frequency and high-frequency resonators, the magnitude of the value of W / D can be adjusted to obtain a better heat dissipation effect, that is, the value of W / D decreases as the frequency of the resonator increases. For example, in the case of low and medium frequencies, i.e., 0 to 3 GHz, a better heat dissipation effect is achieved when the W / D value is set to 1 to 10, whereas in the case of high and ultra-high frequencies, i.e., frequencies of 3 to 7 GHz and higher, a better heat dissipation effect is achieved when the W / D value is set to 0.1 to 1. In the normal frequency overlapping range of surface acoustic wave resonators and bulk acoustic resonators, i.e., frequencies between 2.5 GHz and 3 GHz, the W / D ratio is preferably 0.8 to 2.

[0040] In addition, when the frequency is constant, the heat dissipation efficiency required for the resonator is positively correlated with the power allowance, that is, the higher the power allowance, the higher the heat generated by the resonator and the higher the required heat dissipation efficiency. In this case, the value of the W / D ratio can be set smaller to promote heat dissipation. For example, when the normal power allowance of 1.8GHz is 30dBm, adopting W / D=5 will provide better heat dissipation effect. However, if it is necessary to design a product with a power allowance of 32dBm at 1.8GHz, it can be adjusted to W / D=3. When designing a product with a frequency of 5GHz, the ring resonator can be designed with a ratio of W / D=0.5, and if the product in the 5GHz band has a higher power allowance requirement, it is appropriate to adjust W / D=0.3.

[0041] In some embodiments, the inside of the inner edge of the effective area A1 has a non-effective area A2, i.e., the ring-shaped effective area A1 surrounds the non-effective area A2, the area of ​​the effective area A1 is defined as S1 and the area of ​​the non-effective area A2 is defined as S2, and the relationship between S1 and S2 satisfies the following formula (1). 0.2≦S1 / S2≦12 (1)

[0042] In this case, the heat dissipation efficiency of the resonator can be optimized based on the area S1 of the effective area A1 and the area S2 of the non-effective area A2, and the value of S1 / S2 is negatively correlated with the heat dissipation efficiency. The smaller the value of S1 / S2, the smaller the distance from the heat concentration area of ​​the effective area A1 to the edge of the effective area A1, and the higher the heat dissipation efficiency.

[0043] In some embodiments, at least one of the sound reflecting structure 102, the piezoelectric layer 104, the first electrode 103, and the second electrode 105 is a ring-shaped structure surrounding the non-active area A2, so as to form a ring-shaped active area in the direction perpendicular to the substrate 101. The overlapping area of ​​the sound reflecting structure 102, the piezoelectric layer 104, the first electrode 103, and the second electrode 105 is the active area A1, so in this case, the active area A1 is a ring-shaped active area. In addition, it is preferred that the active area A1 surrounds the non-active area A2, the sound reflecting structure 102 is ring-shaped, the piezoelectric layer 104 is a film layer, and the first electrode 103 and the second electrode 105 are ring-shaped, but other configurations are also possible, and this embodiment is not limited thereto. In addition, when a radio frequency signal is transmitted, the more the first electrode 103 contacts with the surrounding medium, for example, with the substrate 101, the greater its dielectric loss becomes; if the area of ​​the first electrode 103 in the non-effective area A2 is large, the dielectric loss of the signal becomes large, or the requirement for the substrate 101 with high impedance increases, which leads to an increase in cost; therefore, the first electrode 103 in the inner edge of the effective area A1 (non-effective area A2) is etched and removed to form a ring-shaped first electrode 103, and the contact area between the first electrode 103 and the substrate 101 is reduced, thereby reducing the dielectric loss and improving the Q value of the resonator. In addition, in the above resonator, if the sound reflection structure 102 is a ring-shaped structure, the first electrode 103 covers the ring-shaped structure, and the second electrode 105 is located in the area surrounded by the outer edge of the sound reflection structure 102. The ring-shaped structures of the first electrode 103 and the second electrode 105 correspond to the ring-shaped structure of the sound reflecting structure 102 in the direction perpendicular to the substrate 101. The substrate 101 and the first electrode 103 also have a supporting function, and when the sound reflecting structure 102 is a cavity 1021, the first electrode 103 needs to cover the entire cavity 1021, and the second electrode 105 needs to be inside the orthogonal projection of the sound reflecting structure 102, so as to reduce the parasitic capacitance.

[0044] In some embodiments, the ratio value between the shortest distance W from the inner edge to the outer edge of the effective area A1 and the distance D from the center point O of the resonator to the inner edge is negatively correlated with the heat dissipation efficiency required for the resonator, and the smaller the value of the W / D ratio, the smaller the distance from the heat concentration area of ​​the resonator to the edge of the resonator, and the higher the heat dissipation efficiency. In some embodiments, the W of the effective area A1 can be the same or different at different positions, and the shortest distances from multiple A points to the outer edge of the effective area A1 respectively correspond to multiple Ws, and the multiple Ws have maximum and minimum values, and the ratio between the maximum and minimum values ​​is 1.5:1. The maximum and minimum values ​​are the maximum W values ​​of the same effective area A1, and the ratio between the maximum and minimum values ​​is set to 1.5:1 to ensure that the width of the ring-shaped effective area A1 is uniform, thereby ensuring the heat dissipation efficiency of the resonator.

[0045] In some embodiments, the range of possible values ​​for any W of the effective area A1 is 10 to 50 μm, with the best possible range being 20 to 30 μm. The range of possible values ​​for the distance D from the center point O of the resonator to the inner edge is wide, with the best possible range being 10 to 50 μm.

[0046] The sound wave reflecting structure 102 is located on the top surface of the substrate 101 or is embedded within the substrate 101 .

[0047] FIG. 8 is a plan view of a sound reflection structure of a resonator provided by another embodiment of the present application. Referring to FIG. 8, another embodiment of the present application takes the sound reflection structure 102 embedded in the substrate 101, that is, an underground cavity, as an example. In the resonator of this embodiment, the cavity 1021 in the resonator is a groove located in the surface of the substrate 101, and the cavity 1021 is a single polygonal cavity. The plan view shape of the cavity 1021 includes, but is not limited to, a circle, an ellipse, a regular polygon with each angle exceeding 90°, or an irregular polygon or irregular shape with each angle exceeding 90°, and may even be a ring-shaped cavity, in which case the resonator mainly contacts the substrate 101 through the edge of the first electrode 103 to support the resonator and dissipate heat.

[0048] 9 is a cross-sectional view of a resonator provided in another embodiment of the present application. Referring to FIG. 9, another embodiment of the present application takes an example in which the sound wave reflection structure 102 is located on the upper surface of the substrate 101, that is, a ground-type cavity. The first electrode 103 of the resonator has a protruding structure, and a ground-type cavity is formed between the protruding structure and the surface of the substrate 101. When forming a ground cavity, it is not necessary to etch the substrate 101, but only by protruding the first electrode 103 upward to assemble the substrate 101 and the cavity 1021.

[0049] In some embodiments, the height of the sound reflecting structures 102 ranges from 0.1 to 0.5 μm.

[0050] When the sound wave reflection structure 102 is a cavity 1021, in a normal situation, the height of the cavity 1021 is between 0.5-2 μm, and when the resonator resonates, the film layer such as the upper first electrode 103 can be prevented from connecting to the substrate 101. In this embodiment, when the effective area A1 is designed to achieve the required design area of ​​the resonator, W can be designed as small as 20 μm, and compared with the normal sandwich structure, the distortion amount of the film layer is greatly reduced under the same acting force, that is, the force that the resonator can withstand is increased, and thus the reliability of the film layer is greatly enhanced; and when the height of the cavity 1021 is reduced to between 0.1-0.5 μm, the heat dissipation path is further shortened, and thus the heat dissipation efficiency of the resonator is further enhanced.

[0051] Regarding the cavity 1021 fitted inside the substrate 101, if the height of the cavity 1021 is increased, for example, if it is made larger than 0.5 μm, the height of the substrate 101 increases accordingly, and the distance over which the heat of the resonator is transferred from the upper surface of the substrate 101 to the lower surface of the substrate 101 becomes large, and the heat tends to accumulate in the vertical direction of the substrate 101, which is disadvantageous for heat dissipation. If the height of the cavity 1021 is made smaller than 0.1 μm, the film layer of the resonator may be continuous with the substrate 101. In this embodiment, the height of the cavity 1021 is set to be 0.1-0.5 μm, which is smaller than the traditional cavity 1021, and the height of the substrate 101 is accordingly reduced, reducing the distance that heat propagates in the vertical direction of the substrate 101, and the heat is transferred to the bottom of the cavity 1021, i.e., along the horizontal direction of the substrate 101. By reducing the height of the cavity 1021, the resonator is converted from heat dissipation on both sides of the substrate 101 to surface heat dissipation on the bottom surface of the substrate 101, and the heat dissipation efficiency is greatly improved. Furthermore, the height of the cavity 1021 is reduced, which reduces the deposition cost of the sacrificial layer and shortens the release time.

[0052] In the above embodiment, when the acoustic reflection structure 102 is a Bragg reflection layer, there is direct contact between the Bragg reflection layer and the resonant functional layer, so the thinner Bragg reflection layer can reduce the thermal resistance from the resonant functional layer to the underside of the substrate. Therefore, reducing the height to 0.1-0.5 μm can shorten the heat dissipation path, improve the heat dissipation efficiency, and reduce the manufacturing cost of the Bragg reflection layer.

[0053] FIG. 10 is a cross-sectional view of a resonator provided in another embodiment of the present application. Referring to FIG. 10, in another embodiment of the present application, there is a dielectric block 106 in the central region of the sound wave reflecting structure 102, the dielectric block 106 is located in the non-effective region A2, and the sound wave reflecting structure 102 forms a ring-shaped structure by the dielectric block 106.

[0054] In this embodiment, the sound wave reflecting structure 102 of the resonator is described as a cavity 1021 by way of example, the cavity 1021 is located above the substrate 101, and the dielectric block 106 is located in the central region of the cavity 1021, so that the cavity 1021 forms a ring-shaped structure around the dielectric block 106. The first electrode 103 and the piezoelectric layer 104 are both in the form of film layers, and the second electrode 105 forms a ring-shaped structure around the dielectric block 106. The dielectric block 106 is located below the first electrode 103 and in contact with the first electrode 103, supports the first electrode 103 and the resonant function layer thereon, and prevents the resonant function layer from being deformed or collapsed. Possible materials for the dielectric block 106 include silica (SiO2), silicon nitride (Si3N4), amorphous silicon (a-Si), polycrystalline silicon (p-Si), aluminum nitride (AlN), aluminum oxide (Al2O3), magnesium oxide (MgO), zirconium oxide (ZrO2), lead zirconate titanate (PZT), gallium arsenide (GaAs), hafnium oxide (HfO2), titanium oxide (TiO2), or zinc oxide (ZnO).

[0055] Fig. 11 is a plan view of a resonator acoustic reflection structure provided by another embodiment of the present application. Referring to Fig. 11, the dielectric block 106 includes a hollow structure, and a first open passage 1071 is installed at the bottom of the hollow structure, and in a direction parallel to the substrate 101, the first open passage 1071 penetrates the bottom of the hollow structure.

[0056] The material of the dielectric block 106 may be the same as or different from that of the substrate 101. When the material of the dielectric block 106 is the same as that of the substrate 101, the dielectric block 106 may be molded integrally with the substrate 101, or may be presented as a non-integral part. Specifically, when forming the ring-shaped cavity 1021, the dielectric block 106 may be formed integrally with the substrate 101, leaving the substrate 101 in the region of the dielectric block 106. Alternatively, the cavity 1021 is formed first, and then the dielectric block 106 made of the same material as the substrate 101 is formed in the central region of the cavity 1021.

[0057] In another embodiment, the cavity 1021 is located on the surface of the substrate 101, also applying the dielectric block 106 described above.

[0058] 11 and 12, Fig. 12 is a cross-sectional view in the VV' direction of the sound wave reflecting structure shown in Fig. 11, in this embodiment, the sound wave reflecting structure 102 is described by taking the cavity 1021 as an example, and the cavity 1021 is fitted inside the substrate 101. The dielectric block 106 has a hollow structure, and as can be seen by combining the cross-sectional view 12, the dielectric block 106 is a hollow cylinder, in this case, the dielectric block 106 is located in the cavity 1021, and both the inside and outside of the dielectric block 106 are spaces filled with air, that is, in this case, the cavity 1021 is formed by nesting one circular cavity and one ring-shaped cavity. In order to simplify the manufacturing process of the inner and outer spaces of the dielectric block 106, for example, to manufacture the dielectric block 106 in a one-step process, it is preferable to form a first release passage 1071 by removing a part of the material of the dielectric block 106 inside the dielectric block 106 in the direction parallel to the substrate 101, and to place the first release passage 1071 at the bottom of the dielectric block 106, and the first release passage 1071 penetrates the dielectric block 106 in the horizontal direction in the direction parallel to the substrate 101, thereby communicating the inner and outer spaces of the dielectric block 106. Furthermore, in the direction perpendicular to the substrate 101, release holes 108 are placed in the inner and outer spaces of the dielectric block 106 and in the resonant function layer above the dielectric block 106 to release the sacrificial layer in the space. The manufacturing process of the above-mentioned space (including the cavity 1021 and the space inside the dielectric block 106) includes the steps of filling a sacrificial layer material at the location where the space is to be formed, and then allowing an etching solution that reacts with the sacrificial layer material to enter the location of the sacrificial layer material through the release hole 108 and the first release passage 1071 and react with the sacrificial layer material, thereby removing the sacrificial layer and forming the space.

[0059] In addition, the first release passage 1071 can not only pass horizontally through the bottom of the dielectric block 106, but also pass vertically through the dielectric block 106 at the same time, so that the dielectric block 106 has a structure consisting of a plurality of sub-dielectric blocks arranged at intervals. In this case, the spaces between the sub-dielectric blocks can be used as release holes 108. The release holes 108 provided in the inner and outer spaces of the dielectric block 106 and above the spaces between the sub-dielectric blocks can speed up the release of the sacrificial layer.

[0060] Fig. 13 is a plan view of a sound-reflecting structure of a resonator provided in another embodiment of the present application, and Fig. 14 is a cross-sectional view of the resonator in the direction BB' shown in Fig. 13. Referring to Fig. 13 and Fig. 14, the dielectric block 106 includes a solid structure, and a second release passage 1072 is installed on the side wall of the solid structure, and the second release passage 1072 penetrates the solid structure in a direction perpendicular to the substrate 101.

[0061] 13 and 14, in this embodiment, the sound wave reflection structure 102 is a cavity 1021, the cavity 1021 is an underground cavity, the dielectric block 106 in the central region of the cavity 1021 is a solid structure, the cavity 1021 forms a single ring-shaped cavity with the dielectric block 106, and a second open passage 1072 is provided on the side wall of the dielectric block 106, which extends toward the center of the dielectric block 106, and above the second open passage 1072 A release hole 108 is provided in the resonant functional layer, and in a direction perpendicular to the substrate 101, the second release passage 1072 penetrates the sidewall of the dielectric block 106, and the entire sidewall of the dielectric block 106 is recessed inward, so that the release hole 108 communicates with the second release passage 1072 through the resonant functional layer, and the solution or gas for releasing the sacrificial layer passes through the release hole 108 and enters the second release passage 1072, and comes into contact with and reacts with the sacrificial layer in the cavity 1021, thereby removing the sacrificial layer and forming the cavity 1021. An example will be described in which the cavity 1021 is a single ring-shaped cavity, the piezoelectric layer 104 is a film layer, and the first electrode 103 and the second electrode 105 are both ring-shaped. The cavity 1021 and the second electrode 105 correspond to each other in the vertical direction, and the cavity 1021 is larger than the second electrode 105, that is, the shape of the cavity 1021 is an equal-proportion expansion of the shape of the effective area A1. In the direction perpendicular to the substrate 101, the shape of the dielectric block 106 may be the same as or different from the shape of the cavity 1021. The second release passage 1072 and the release hole 108 installed inside the resonator improve heat dissipation, and at the same time, greatly facilitate the design layout when connecting between the resonators, minimize the chip area, and improve the integration degree.

[0062] 15-17, in another embodiment of the present application, there is a gap between the piezoelectric layer 104 and the second electrode 105 and / or between the first electrode 103 and the piezoelectric layer 104 in a direction perpendicular to the substrate 101, and the gap is located in the non-effective area A2. In this case, the effective area A1 forms a ring-shaped effective area A1 around the gap in the non-effective area A2. At the same time, in the area corresponding to the gap, the upper and lower film layers in the area where the gap is located cannot contact each other in a direction perpendicular to the substrate 101 and are separated from each other, thereby weakening or suppressing the generation of extra parasitic vibration. Note that providing a gap in the resonator includes, but is not limited to, providing one or two gaps between both layers among the substrate 101, the first electrode 103, the piezoelectric layer 104, and the second electrode 105 in the non-effective area A2.

[0063] 15 is a cross-sectional view of a resonator provided by another embodiment of the present application. Referring to FIG. 15, the upper surface of the first electrode 103 and / or the upper surface of the piezoelectric layer 104 has a first recess 1091, and a first gap 1101 is formed between at least one of the first recess 1091 and the second electrode 105.

[0064] 15, the sound wave reflecting structure 102 is ring-shaped and embedded in the substrate 101. The upper surface of the first electrode 103 has a first recess 1091, the piezoelectric layer 104 deposited in the first recess 1091 forms a third recess 1092 as the shape of the first recess 1091 changes, and the second electrode 105 is deposited on the piezoelectric layer 104 across the third recess 1092, in this case, a first gap 1101 is formed between the third recess 1092 and the second electrode 105. In another modified embodiment, the first electrode 103 is a film layer having no recess on its upper surface, and a first recess 1091 is directly formed in the piezoelectric layer 104 by a method such as etching, and the second electrode 105 is evaporated onto the piezoelectric layer 104 across the first recess 1091, thereby forming a first gap 1101 between the first recess 1091 and the second electrode 105.

[0065] 16 is a cross-sectional view of a resonator provided in another embodiment of the present application. Referring to FIG. 16, in this embodiment, the sound wave reflecting structure 102 is ring-shaped and embedded inside the substrate 101. In a direction perpendicular to the substrate 101, there is a first gap 1101 between the piezoelectric layer 104 and the second electrode 105. The step of forming the first gap 1101 includes first completely etching the central region of the first electrode 103 to form a first recess 1091, and exposing the substrate 101 from the surface of the substrate 101. In this case, the first electrode 103 is ring-shaped. Next, the piezoelectric layer 104 is grown on the first electrode 103 and the upper surface of the exposed substrate 101 to form a third recess 1092 corresponding to the position and shape of the exposed substrate 101 on the upper surface of the piezoelectric layer 104. Finally, the second electrode 105 is grown on the piezoelectric layer 104, and the second electrode 105 straddles the third recess 1092 above the third recess 1092, thereby forming the first gap 1101 between the piezoelectric layer 104 and the second electrode 105. The reason for providing a gap between the piezoelectric layer 104 and the second electrode 105 in the direction perpendicular to the substrate 101 is that the second electrode 105 and the piezoelectric layer 104 cannot contact each other in the direction perpendicular to the substrate 101 due to the separation of the first gap 1101, and therefore no extra parasitic vibration is generated. In other embodiments, a gap may be formed between the first electrode 103 and the piezoelectric layer 104. In this case, the central region of the first electrode 103 may be partially or entirely etched to form a gap between the piezoelectric layer 104 grown flat thereon, or the first electrode 103 may be etched to expose the surface of the substrate 101, and a gap is formed between the piezoelectric layer 104 grown flat and the exposed surface of the substrate 101.

[0066] In the embodiment of FIG. 15 and FIG. 16, the sound wave reflecting structure 102 is embedded in the substrate 101. In other embodiments, the sound wave reflecting structure 102 may be located on the surface of the substrate 101. In this case, the middle region of the first electrode 103 may be partially or entirely etched, or the middle region of the piezoelectric layer 104 may be etched to form a first gap 1101 between the piezoelectric layer 104 and the second electrode 105. The sound wave reflecting structure 102 may be a cavity 1021 or a Bragg reflecting layer. Etching the first electrode 103 and the piezoelectric layer 104 both affect the piezoelectricity of the piezoelectric layer 104, and the first electrode 103 and the piezoelectric layer 104 may not be etched or otherwise processed, so as to improve the performance of the resonator.

[0067] Fig. 17 is a cross-sectional view of a resonator provided by another embodiment of the present application. Referring to Fig. 17, in this embodiment, neither the first electrode 103 nor the piezoelectric layer 104 is subjected to processing such as etching. The sound wave reflection structure 102 is located on the surface of the substrate 101 and is sandwiched between the first electrode 103 and the substrate 101. The first electrode 103, or the first electrode 103 and the piezoelectric layer 104, are recessed downward to form a second recess 1093, and a second gap 1102 is formed between at least one second recess 1093 and the second electrode 105, and the second gap 1102 is located in the non-effective area A2. That is, the first electrode 103 protrudes at the position of the effective area A1 and is recessed downward in the non-effective area A2 to form the second recessed portion 1093, and the piezoelectric layer 104 and the second electrode 105 are grown flatly upward to form the second recessed portion 1093, so that a second gap 1102 is formed between the second recessed portion 1093 of the first electrode 103 and the piezoelectric layer 104. Alternatively, the first electrode 103 protrudes at the position of the effective area A1 and is recessed downward in the non-effective area A2, and the piezoelectric layer 104 is grown directly on the first electrode 103 and is recessed along with the recess of the first electrode 103 to form the second recessed portion 1093 on the piezoelectric layer 104. In this case, the second gap 1102 is formed between the second recessed portion 1093 of the piezoelectric layer 104 and the second electrode 105 that is grown flat. The sound wave reflecting structure 102 is a cavity 1021. In this embodiment, the second gap 1102 separates the piezoelectric layer 104 and the second electrode 105 in the direction perpendicular to the substrate 101, so that the resonator at that location does not generate extra parasitic vibrations. The above gap may be filled with air or a medium material as long as the gap does not generate extra parasitic vibrations in that region.

[0068] FIG. 18 is a cross-sectional view of a resonator provided by another embodiment of the present application. Referring to FIG. 18, another embodiment of the present application is described as an example in which the sound wave reflection structure 102 is a Bragg reflection layer 1022. In the resonator of this embodiment, the resonator includes a Bragg reflection layer 1022 located between the first electrode 103 and the substrate 101. The Bragg reflection layer 1022 may be located on the surface of the substrate 101, or the substrate 101 is etched into the shape of a cavity, and the Bragg reflection layer 1022 is formed inside the cavity. In a direction perpendicular to the substrate 101, the Bragg reflection layer 1022 includes a high acoustic impedance film layer and a low acoustic impedance film layer arranged alternately. Preferably, the Bragg reflection layer 1022 is directly formed on the surface of the substrate 101, in which case there is no need to perform processing such as etching on the substrate 101, simplifying the production process.

[0069] Fig. 19 is a plan view of a resonator assembly provided by another embodiment of the present application. Referring to Fig. 19, based on the above resonator, another embodiment of the present application provides a resonator assembly, in which a bulk acoustic resonator is electrically connected to at least one electric structure 1200, the electric connection includes parallel connection or series connection, and the electric structure 1200 can be located in the non-active area A2, in this case, the area of ​​the non-active area A2 inside the ring resonator can be fully utilized, and the size of the resonator assembly can be reduced overall.

[0070] In some embodiments, at least one electrical structure 1200 is electrically connected to the non-active area A2, and the electrical structure 1200 includes an electronic device or circuit. The electronic device includes a capacitance or an inductance, and the circuit includes an LC circuit. The electrical structure 1200 is electrically connected to the active area A1, and the series resonant frequency Fs or the parallel resonant frequency Fp can be adjusted, greatly enhancing the tunability of the performance of the active area A1. For example, if the electrical structure 1200 is an inductance, the Fp of the active area A1 can be shifted to the right, and the bandwidth of the filter is increased.

[0071] Fig. 20 is a cross-sectional view in the CC' direction of the resonator assembly shown in Fig. 19. Referring to Fig. 20, the first electrode 103 of the effective area A1 is connected to one end of the electric structure 1200 via a first connection part E, and the second electrode 105 of the effective area A1 is connected to the other end of the electric structure 1200 via a second connection part F, the material of the first connection part E may be the same as the material of the first electrode 103 or may be different, and the material of the second connection part F may be the same as the material of the second electrode 105 or may be different.

[0072] Therefore, based on the above resonator, the present application further puts forward a resonator sealing structure for sealing the above resonator.

[0073] For devices such as filters, duplexers, and multiplexers that are single resonators or cascades of single resonators, they need to be subsequently encapsulated to reduce electromagnetic signal interference, reduce environmental influences, and increase service life. The traditional encapsulation process often uses encapsulation film technology, which can be simply described as completely covering a device with a layer of film. Another encapsulation method is to bond a main wafer and a sub-wafer, that is, to cover the sub-wafer on the top of the main wafer (the wafer containing the circuit structure), to draw out the circuit with conductors, and to fabricate copper pillars for the conductors.

[0074] 21-22 are cross-sectional views of a sealing structure of a resonator provided by another embodiment of the present application. Based on the above resonator, another embodiment of the present application provides a sealing structure of a resonator, in which a sealing film 1300 is installed above any of the above bulk acoustic resonators, the sealing film 1300 seals the effective area A1, and provides sound insulation between the effective area A1 and the sealing film 1300. That is, the sealing film 1300 is installed on the side of the second electrode 105 away from the substrate 101, and is fixedly connected to the periphery of the piezoelectric layer 104 exposed around the second electrode 105, thereby sealing the resonator. This embodiment provides sealing of a single device, and the same applies to sealing of a filter and a duplexer.

[0075] In order to increase the stability of the sealing film 1300 and prevent the sealing film 1300 from collapsing, the sealing film 1300 is directly connected to the non-effective area A2, or a support is provided between the sealing film and the non-effective area A2. That is, the sealing film 1300 extends to the non-effective area A2 and is directly connected to the non-effective area A2, or a support is provided between the sealing film and the non-effective area.

[0076] Referring to FIG. 21, in the sealing structure of this embodiment, the sealing film 1300 and the non-effective area A2 are directly connected, or a support is provided between the sealing film 1300 and the non-effective area A2. The sealing film 1300 extends from the periphery of the resonator to above the non-effective area A2 of the resonator, and further extends from the non-effective area A2 to the periphery of the resonator to cover the entire resonator. The direct connection may be a method in which the sealing film 1300 and the non-effective area A2 are bonded via a bonding agent, or other fixed connection methods. The sealing of the filter formed for the resonator is to extend the sealing film 1300 from the periphery of multiple resonators to the non-effective areas A2 of multiple resonators to completely cover the filter. In addition to the peripheral support attachment points, the resonator increases the non-effective area A2 as a new attachment point to support the sealing film 1300, effectively improving the problem of the sealing film falling, and improving the reliability of the wafer-packaged (WLP) structure.

[0077] Referring to FIG. 22, in the encapsulation structure, the support includes a metal pillar 1400, the bottom of which is electrically connected to the first electrode 103 or the second electrode 105, the top of which is exposed to the outside of the encapsulation film 1300 and electrically connected to the outside, and the metal pillar 1400 is located in the non-effective area A2. Meanwhile, the installation of the metal pillar 1400 in the non-effective area A2 can enhance heat dissipation. In the encapsulation structure without the metal pillar 1400, the heat is dissipated by being transferred to the lower surface of the substrate 101, and when the heat generated by the device is large, the heat in the substrate 101 is likely to accumulate. The metal pillar 1400 in this embodiment can simultaneously dissipate the heat generated by the resonator in two directions, the substrate 101 and the metal pillar 1400, and the metal pillar 1400 itself has a good heat dissipation effect, and the metal pillar 1400 of the substrate 101 greatly increases the heat dissipation efficiency of the device. On the other hand, the volume of the device can be reduced, and in the encapsulation structure without the normal metal pillar 1400, it is necessary to install metal structures electrically connected to the outside on both sides of the encapsulation film 1300 to provide electrical connection for the device. In this embodiment, the bottom of the metal pillar 1400 is electrically connected to the first electrode 103 or the second electrode 105, and the top of the metal pillar 1400 is exposed to the outside of the encapsulation film 1300 and electrically connected to the power source of the outside, so that there is no need to install a metal structure electrically connected to the outside again on the outside, and the volume of the device is effectively reduced. At the same time, the process difficulty and cost are also reduced, and the yield rate of the device is improved.

[0078] Based on the above embodiment, another embodiment of the present application further provides a filter, which includes a resonator of any of the types of the above embodiments.

[0079] Based on the above embodiment, another embodiment of the present application further provides an electronic device, including a resonator of any of the types of the above embodiments.

[0080] Based on the above embodiment, another embodiment of the present application further provides a method for fabricating a resonator.

[0081] Another embodiment of the present application provides a method for fabricating a bulk acoustic resonator, the method includes the steps of: providing a substrate 101; forming an acoustic reflection structure 102 on the substrate 101; and sequentially forming a first electrode 103, a piezoelectric layer 104 and a second electrode 105 on the substrate 101 and the acoustic reflection structure 102, wherein in a direction perpendicular to the substrate, an overlapping area of ​​the acoustic reflection structure 102, the first electrode 103, the piezoelectric layer 104 and the second electrode 105 constitutes an effective area A1, the resonator has a ring-shaped effective area A1, an arbitrary point on an inner edge of the effective area A1 is point A, a distance from point A to a center point of the resonator is D, and a shortest distance from point A to an outer edge of the effective area A1 is W, and 0.1≦W / D≦10. The preferred material of the substrate 101 is Si / sapphire / spinel, the acoustic reflection structure 102 includes a cavity 1021 or a Bragg reflection layer 1022, the preferred material of the first electrode 103 is molybdenum (Mo), other possible materials are metal or alloy materials such as gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co) or aluminum (Al), etc. The preferred material of the piezoelectric layer 104 is aluminum nitride (AlN), and further possible materials include zinc oxide (ZnO), zinc sulfide (ZnS), lithium tantalate (LiTaO3), cadmium sulfide (CdS), lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), etc. The preferred material of the second electrode 105 is molybdenum (Mo), and other selectable materials are metal materials or alloy materials such as gold (Au), tungsten (W), copper (Cu), nickel (Ni), titanium (Ti), niobium (Nb), silver (Ag), tantalum (Ta), cobalt (Co) or aluminum (Al). The materials of the substrate 101, the first electrode 103, the second electrode 105 and the piezoelectric layer 104 include, but are not limited to, the above-mentioned materials. In the direction perpendicular to the substrate 101, the inside of the ring-shaped effective area A1 has a non-effective area A2, and the ring-shaped effective area A1 surrounds the non-effective area A2.

[0082] Based on the above, it can be seen that the present application provides a resonator and assembly, a filter, an electronic device, as well as a manufacturing method and a sealing structure, and the resonator has a ring-shaped effective area A1, so that the temperature can be kept basically constant in the working state, and the heat dissipation efficiency can be high; and on the premise that the distance W from the inner edge to the outer edge of the effective area A1 and the distance D from the center point of the effective area A1 to the inner edge satisfy the relationship of 0.1≦W / D≦10, the distance W can be adjusted according to the needs of the frequency and power allowance of the resonator, so as to ensure the heat dissipation efficiency of the resonator and improve the power allowance. At the same time, the central area of ​​the substrate of the resonator is provided with an open passage and an open hole, so as to rationally utilize the space and reduce the size of the resonator; the height of the cavity is reduced, the heat dissipation efficiency is improved, and the deposition cost of the sacrificial layer is reduced. The first electrode 103 is etched to reduce the contact area between the first electrode 103 and the substrate 101, thereby reducing dielectric loss, and the central region of the first electrode 103 is etched to form a gap between the first electrode 103 and the piezoelectric layer 104, so that no resonance occurs in the central region of the non-effective region A2. In sealing the resonator, the newly added force point is placed in the non-effective region A2, which significantly improves the reliability of the sealing structure, reduces the process difficulty, and improves the yield.

[0083] Each embodiment in this specification is described in a gradual or parallel or gradual and parallel combination, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between each embodiment can be referred to each other. The method, resonator assembly, filter, and electronic device disclosed in the embodiment correspond to the device disclosed in the embodiment, so the description is relatively simple, and the relevant parts can be referred to the description of the device parts.

[0084] In the description of the present application, the drawings and the examples are illustrative rather than restrictive. Similar symbols throughout the specification and examples label similar structures. For ease of understanding and description, the drawings may exaggerate the thickness of a layer, film, panel, region, etc. In addition, when an element such as a layer, film, region, or base plate is referred to as being "on" or "in" another element, the element may be directly on the other element, or there may be an intermediate element. In addition, "on" means that an element is positioned on or below another element, but does not essentially mean that the element is positioned on the top side of another element according to the direction of gravity.

[0085] The orientations or positional relationships indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. are orientations or positional relationships shown based on the drawings, and are merely for convenience of explanation and simplicity of the present application, and are not intended to indicate or imply that the devices or elements referred to have a particular orientation and must be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application. When an assembly is identified as "connected" to another assembly, it may be directly connected to the other assembly, or there may be a centrally located assembly at the same time.

[0086] It should be further noted that, in this specification, terms such as "first" and "second" are used merely to distinguish an entity or operation from other entities or operations, and do not necessarily require or imply that such an existential relationship or ranking exists between the entities or operations. Furthermore, terms such as "comprises," "contains," or other variations thereof, imply non-exclusive inclusion. A product or device that includes a set of elements includes not only those elements, but also other elements not expressly listed, or further includes elements that were already present in such product or device. Unless further limited, an element defined by the phrase "comprises a..." does not exclude the presence of additional identical elements in a product or device that includes the above elements.

[0087] The above description of the disclosed embodiments enables one skilled in the art to make or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Thus, the present application is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A bulk acoustic resonator comprising: A substrate; a first electrode having an acoustic reflection structure disposed between the first electrode and a substrate; a second electrode with a piezoelectric layer between the first electrode and the second electrode; In a direction perpendicular to the substrate, an overlapping area of ​​the acoustic reflection structure, the first electrode, the piezoelectric layer, and the second electrode constitutes an effective area, and the resonator has a ring-shaped effective area; An arbitrary point on the inner edge of the effective area is defined as point A, a distance from point A to the center point of the resonator is defined as D, and a shortest distance from point A to the outer edge of the effective area is defined as W, and 0.1≦W / D≦10. A bulk acoustic resonator comprising:

2. 2. The bulk acoustic resonator according to claim 1, wherein a non-effective region is provided inside an inner edge of the effective region, an area of ​​the effective region is S1, an area of ​​the non-effective region is S2, and a relationship between S1 and S2 satisfies the following formula (1): 0.2≦S1 / S2≦12 (1)

3. the shortest distances from the plurality of A points to the outer edge of the effective area correspond to a plurality of Ws, the plurality of Ws have maximum and minimum values, and the ratio of the maximum value to the minimum value is 1.5:1; 2. The bulk acoustic resonator of claim 1 .

4. The range of possible values ​​for any of the W's is 10 μm to 50 μm.

2. The bulk acoustic resonator of claim 1 .

5. At least one of the acoustic reflection structure, the piezoelectric layer, the first electrode, and the second electrode is annular in structure so as to form an annular effective area in a direction perpendicular to the substrate.

2. The bulk acoustic resonator of claim 1 .

6. The acoustic reflection structure is located on the top surface of the substrate or is embedded within the substrate.

2. The bulk acoustic resonator of claim 1 .

7. The height range of the sound wave reflection structure is 0.1 μm to 0.5 μm; 2. The bulk acoustic resonator of claim 1 .

8. a dielectric block is provided in a central region of the sound wave reflection structure, the dielectric block is located in the non-effective region, and the sound wave reflection structure forms a ring-shaped structure with the dielectric block; 3. The bulk acoustic resonator of claim 2.

9. the dielectric block includes a hollow structure, a first release passage is provided at a bottom of the hollow structure, and the first release passage penetrates the bottom of the hollow structure in a direction parallel to the substrate; 9. The bulk acoustic resonator of claim 8.

10. The dielectric block includes a solid structure, and a second release passage is provided on a sidewall of the solid structure, and the second release passage penetrates the solid structure in a direction perpendicular to the substrate.

9. The bulk acoustic resonator of claim 8.

11. a gap is present between the piezoelectric layer and the second electrode and / or between the first electrode and the piezoelectric layer in a direction perpendicular to the substrate, the gap being located in the non-effective region; 3. The bulk acoustic resonator of claim 2.

12. an upper surface of the first electrode and / or an upper surface of the piezoelectric layer has a first recessed portion, and a first gap is formed between at least one of the first recessed portion and the second electrode; 12. The bulk acoustic resonator of claim 11.

13. the first electrode, or the first electrode and the piezoelectric layer, are recessed downward to form a second recess, and a second gap is formed between at least one of the second recesses and the second electrode; 12. The bulk acoustic resonator of claim 11.

14. A resonator assembly comprising the bulk acoustic resonator of any one of claims 1 to 13, wherein the bulk acoustic resonator is electrically connected to at least one electrical structure, the electrical structure being located in the non-active region.

13. A resonator assembly comprising:

15. A sealing structure for a resonator based on the bulk acoustic resonator according to any one of claims 1 to 13, wherein a sealing film is provided above the resonator, the sealing film seals the effective area, and a gap between the effective area and the sealing film is sound-insulated. A sealing structure for a resonator.

16. The sealing film and the non-effective area are directly connected to each other, or a support is provided between the sealing film and the non-effective area. The sealing structure according to claim 15 .

17. the support includes a metal pillar, a bottom of the metal pillar is electrically connected to the first electrode or the second electrode, and a top of the metal pillar is exposed to the outside of the sealing film and electrically connected to the outside. The sealing structure according to claim 16 .

18. A filter comprising a resonator according to any one of claims 1 to 17. A filter characterized by:

19. An electronic device comprising the resonator according to any one of claims 1 to 17.

1. An electronic device comprising:

20. 1. A method for fabricating a bulk acoustic resonator, comprising the steps of: Providing a substrate; forming an acoustic reflection structure on the substrate; sequentially forming a first electrode, a piezoelectric layer, and a second electrode on the substrate and the acoustic reflection structure; In a direction perpendicular to the substrate, an overlapping area of ​​the acoustic reflection structure, the first electrode, the piezoelectric layer, and the second electrode constitutes an effective area, and the resonator has a ring-shaped effective area; An arbitrary point on the inner edge of the effective area is defined as point A, a distance from point A to the center point of the resonator is defined as D, and a shortest distance from point A to the outer edge of the effective area is defined as W, and 0.1≦W / D≦10. A method for fabricating a bulk acoustic resonator comprising the steps of:

Images