Micro-electro-mechanical resonator device

Abstract

The invention discloses a micro-electro-mechanical resonance device which comprises a device layer and a sealing cover which are arranged in a stacked mode. The device layer comprises a resonance main body, an electrode assembly arranged corresponding to the resonance main body, and a fixed area arranged on the outer side of the resonance main body, and a gap is formed between the resonance main body and the fixed area; the sealing cover comprises a film, a side wall connected to the periphery of the film and a supporting part located on the inner side of the side wall, the side wall and the film enclose to form a sealing cavity, and the sealing cavity at least covers the resonance body; two ends of the side wall are respectively in sealed connection with the film and the fixed area, one end of the support part is connected with the film, and the other end is connected with the electrode assembly and / or the fixed area in the device layer to limit the maximum suspension size of the sealed cavity film. The supporting part can play a role in supporting the thin film, the pressure bearing capacity of the sealing cover can be enhanced, and the requirement for the thickness of the thin film is lowered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-electro-mechanical systems, and in particular to a micro-electro-mechanical resonator. BACKGROUND

[0002] MEMS (Micro-Electro-Mechanical Systems) resonators generally adopt semiconductor silicon processing or SOI (Silicon on Insulator) technology, form a resonant structure through etching, and support wafer-level batch production. This technology uses silicon-based microfabrication processes to achieve the integration of mechanical resonant structures and drive circuits, which not only greatly reduces the size of the device, but also improves production efficiency and environmental adaptability. In the fields of 5G communication, Internet of Things devices, automotive electronics, and high-precision timing control, MEMS oscillators are gradually replacing traditional solutions.

[0003] The core performance of the MEMS oscillator is mainly reflected in the three dimensions of frequency stability, phase noise and power consumption. As a key component of the oscillator, the Q value (Quality factor) of the resonator will directly affect these performance indicators: a high Q value means a narrower resonant peak width, resulting in better frequency selectivity and lower phase noise. However, air damping in the atmospheric environment can cause the Q value of the resonator to deteriorate sharply, and gas molecule collisions can also cause random fluctuations in frequency. Vacuum-sealed packaging can effectively reduce the gas damping effect by creating a low-pressure environment (usually below 1 Pa), effectively improving the Q value of the resonator.

[0004] However, in existing MEMS processes, bonding techniques such as anodic bonding and eutectic bonding are commonly used. However, bonding techniques require the additional introduction of a bonding ring, which significantly reduces the chip area utilization rate, and bonding techniques usually involve high-temperature processes that can introduce thermal stress and affect the performance of the resonator. In contrast, thin-film sealing processes that can achieve in-situ packaging can effectively solve this problem, but the thickness of the sealing cover formed by traditional thin-film processes is limited by the process, resulting in poor strength and difficulty in withstanding the pressure from subsequent processes such as plastic packaging. Therefore, under the conditions of existing technology, how to increase the pressure-bearing performance of the sealing cover with limited thickness has become a problem that needs to be solved by those skilled in the art. SUMMARY

[0005] Therefore, the present application provides a micro-electro-mechanical resonator that can effectively improve the pressure-bearing capacity.

[0006] The micro-electro-mechanical resonator provided by the present application comprises a device layer and a sealing cover which are arranged in layers.

[0007] The device layer comprises a resonance main body, an electrode assembly arranged correspondingly to the resonance main body, and a fixed region arranged outside the resonance main body (not necessarily on the outside), and a gap is formed between the resonance main body and the fixed region;

[0008] The sealing cover comprises a film, a side wall connected to the periphery of the film, and a support part located inside the side wall, the side wall and the film form a sealed cavity, and the sealed cavity covers at least the resonance main body;

[0009] The two ends of the side wall are sealedly connected to the film and the fixed region respectively, one end of the support part is connected to the film, the other end is connected to the electrode assembly and / or the fixed region in the device layer, so as to limit the maximum space size of the sealed cavity, and the support part is arranged in a spaced manner with the resonance main body.

[0010] In some embodiments, the support part comprises a plurality of support columns arranged in the sealed cavity and spaced from the side wall, and the area of one end of each support column connected to the film is greater than the area of the other end connected to the device layer.

[0011] In some embodiments, the support column comprises a top surface connected to the film, a bottom surface connected to the device layer, and a side surface connected between the top surface and the bottom surface, the side surface extends in a concave manner from the top surface towards the bottom surface.

[0012] In some embodiments, the top surface and the bottom surface have the same shape, and the projection of the bottom surface on the film is located in the top surface, and the centers of the top surface and the bottom surface coincide in the direction perpendicular to the top surface and the bottom surface.

[0013] In some embodiments, the included angle between the side surface and the surface of the device layer facing the film is 35°-50°.

[0014] In some embodiments, the minimum distance between any two adjacent support columns is less than or equal to 50μm.

[0015] In some embodiments, a release hole is provided on the film, and the distance between the release hole and the adjacent support column is 3-10μm.

[0016] In some embodiments, a through hole is provided on the sealing cover, the through hole penetrates the film and the support column in sequence, a conductive part is arranged in the through hole, and the conductive part is electrically connected to the electrode assembly and / or the resonance main body.

[0017] In some embodiments, the resonant body comprises two vibration arms arranged opposite to each other, and a beam structure and an anchor point between the two vibration arms, the anchor point being connected to the vibration arms through the beam structure;

[0018] Each of the vibration arms comprises two vibration arm units, the support part comprises two support blocks connected to the side walls, the support blocks extending from the side walls to between the adjacent two vibration arm units of different vibration arms, the two support blocks being located on opposite sides of the beam structure, the sealing cavity is shaped to match the shape of the resonant body, the sealing cavity covers the resonant body, and the electrode assembly is located outside the sealing cavity.

[0019] In some embodiments, the distance between the two inner walls on opposite sides of the vibration arm unit is less than or equal to 50 μm.

[0020] The micro-electro-mechanical resonator provided by the present application can increase the pressure bearing capacity of the thin film by arranging the support part between the thin film and the device layer, the support part can support the thin film, form a local rigid support at the part of the thin film suspended relative to the device layer, hinder the deformation of the area of the thin film supported by the rigid support and the surrounding area, reduce the maximum deformation of the thin film, thereby enhancing the pressure bearing capacity of the thin film and reducing the risk of damage to the thin film when subjected to pressure. By arranging the support part to increase the pressure bearing capacity of the thin film, the requirement for the thickness of the thin film can be reduced, and in the case of the same pressure bearing capacity, the thickness of the thin film can be greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A top view of the micro-electro-mechanical resonator provided by the first embodiment of the present application;

[0022] Figure 2 A structure diagram of the resonant body in the first embodiment of the present application; Figure 1

[0023] A cross-sectional view of the micro-electro-mechanical resonator along line A-A in the first embodiment of the present application; Figure 3 Figure 1 A simulation relationship diagram of support columns with different distances and maximum stress;

[0024] Figure 4 A simulation relationship diagram of support columns with different inclination angles and maximum stress;

[0025] Figure 5 A cross-sectional view of the micro-electro-mechanical resonator provided by the second embodiment of the present application;

[0026] Figure 6 A cross-sectional view of the micro-electro-mechanical resonator provided by the third embodiment of the present application;

[0027] Figure 7 A cross-sectional view of the micro-electro-mechanical resonator provided by the third embodiment of the present application;​

[0028] Figure 8 A top view of a micro-electromechanical resonator device according to a fourth embodiment of the application;

[0029] Figure 9 A top view of a micro-electromechanical resonator device according to a fifth embodiment of the application.

[0030] In the figure: 10, resonator; 12, device layer; 14, sealing cover; 16, resonator body; 18, electrode assembly; 20, fixed region; 22, sealed cavity; 24, vibration arm; 26, beam structure; 28, anchor point; 29, vibration arm monomer; 30, coupling beam; 32, connecting beam; 34, driving electrode; 36, sensing electrode; 38, thin film; 40, side wall; 42, substrate; 44, buried oxygen layer; 46, support column; 48, top surface; 50, bottom surface; 52, side surface; 54, conductive member; 56, first reinforcing layer; 58, second reinforcing layer; 60, release hole; 62, support block. DETAILED DESCRIPTION

[0031] The application will be further described below in conjunction with the drawings and specific embodiments. It should be noted that the following described embodiments or technical features can be combined in any manner to form new embodiments, without conflict.

[0032] It should be noted that all directional indications, such as upper, lower, left, right, front, back, inner, outer, top, bottom, etc., are only used to explain the relative position relationship between components, etc., in a certain posture (as shown in the drawings), and if the posture changes, the directional indications will also change accordingly.

[0033] It should also be noted that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or can have a mediating element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or can have a mediating element.

[0034] Please refer to Figures 1 to 3The first embodiment of the present application provides a micro-electro-mechanical resonant device 10, which comprises a device layer 12 and a sealing cover 14 arranged in a stack, the device layer 12 comprises a resonant main body 16, an electrode assembly 18 and a fixed region 20, the resonant main body 16 is used to generate resonance, the electrode assembly 18 is arranged correspondingly with the resonant main body 16 and is used to drive the resonant main body 16 to resonate and sense the resonance of the resonant main body 16, and the fixed region 20 is arranged with a spacing from the resonant main body 16 and is at least partially located at the periphery of the device layer 12 to be connected with the sealing cover 14. The sealing cover 14 is connected with the fixed region 20 and is arranged with a spacing from the resonant main body 16, and a sealing cavity 22 is formed on the side of the sealing cover 14 close to the device layer 12, which covers at least the resonant main body 16 to avoid affecting the resonance of the resonant main body 16.

[0035] The resonant main body 16 comprises two vibration arms 24 arranged with a spacing and a beam structure 26 and an anchor point 28 between the two vibration arms 24, the anchor point 28 is connected with the vibration arm 24 through the beam structure 26, and the anchor point 28 is fixed to a substrate 42 to support the vibration arm 24. The electrode assembly 18 is arranged correspondingly with the vibration arm 24 and drives the vibration arm 24 to resonate and senses the resonance of the vibration arm 24 through piezoelectric driving or electrostatic driving.

[0036] Each vibration arm 24 comprises two vibration arm units 29 connected with each other, and the two vibration arm units 29 of the same vibration arm 24 are arranged in a direction perpendicular to the arrangement direction of the two vibration arms 24, that is, the arrangement direction of the two vibration arm units 29 of the same vibration arm 24 is perpendicular to the arrangement direction of the two vibration arms 24.

[0037] The beam structure 26 comprises a coupling beam 30 and a connecting beam 32, the coupling beam 30 is fixedly connected with the connecting beam 32 and has a cross shape, the coupling beam 30 connects the two vibration arms 24, and the two ends of the connecting beam 32 are fixedly connected with the anchor point 28. The two vibration arms 24 are symmetrically arranged relative to the connecting beam 32, and the two vibration arm units 29 of the same vibration arm 24 are symmetrically arranged relative to the coupling beam 30.

[0038] In other embodiments, the resonant main body 16 can also be a double-ended tuning fork structure, a multi-ring structure, a cantilever beam structure 26, etc.

[0039] The electrode assembly 18 comprises a driving electrode 34 and a sensing electrode 36, the driving electrode 34 is used to drive the vibration arm 24 to resonate, and the sensing electrode 36 is used to sense the resonance of the vibration arm 24, one of the driving electrode 34 and the sensing electrode 36 is located between the two vibration arms 24, and the other is located outside the vibration arm 24.

[0040] In an optional example, the number of the driving electrodes 34 and the sensing electrodes 36 is two, two driving electrodes 34 are respectively located at the outer side of the two vibration arms 24, each driving electrode 34 drives two vibration arm units 29 of a corresponding vibration arm 24 to resonate. The two sensing electrodes 36 are both located between the two vibration arms 24, one sensing electrode 36 is located between two adjacent vibration arm units 29 (referring to two vibration arm units 29 of different vibration arms 24), and the other sensing electrode 36 is located between the other two vibration arm units 29, each sensing electrode 36 senses the resonance of the adjacent two vibration arm units 29. In use, the anchor points 28 can be used as bias electrodes, that is, a direct current bias voltage can be applied to the anchor points 28, so that the beam structure 26 and the vibration arms 24 maintain the same direct current bias voltage, and the driving electrodes 34 apply alternating voltage, so as to form alternating electrostatic force between the driving electrodes 34 and the vibration arms 24, so as to drive the vibration arms 24 to resonate.

[0041] In an embodiment, the sealing cover 14 includes a thin film 38, a side wall 40 connected to the periphery of the thin film 38, and a support portion located inside the side wall 40, the side wall 40 and the thin film 38 enclose the sealing cavity 22, which covers at least the resonance main body 16. In an optional example, the area of the sealing cavity 22 is larger than the area of the resonance main body 16, which not only covers the resonance main body 16, but also covers the electrode assembly 18.

[0042] The thin film 38 is spaced apart from the device layer 12, and the two ends of the side wall 40 are connected to the thin film 38 and the fixed area 20 of the device layer 12, respectively. This structure is formed by a MEMS thin film sealing process and achieves a sealing effect, so that the resonance main body 16 is in a sealed space, reducing the air damping loss of the resonance main body 16, thereby improving the Q value of the micro-electro-mechanical resonator 10. One end of the support portion is connected to the thin film 38, and the other end is connected to the electrode assembly 18 and / or the fixed area 20 in the device layer 12, so as to limit the suspended size of the thin film 38. The support portion is spaced apart from the resonance main body 16 to avoid affecting the resonance of the resonance main body 16.

[0043] By arranging the support portion between the thin film 38 and the device layer 12, the support portion can support the thin film 38, and form a local rigid support for the suspended part of the thin film 38, which can hinder the deformation of the area and the surrounding area of the thin film 38 that is rigidly supported, thereby reducing the maximum deformation of the thin film 38, enhancing the pressure bearing capacity of the thin film 38, and reducing the risk of deformation damage of the thin film 38 under pressure. Moreover, by arranging the support portion to increase the pressure bearing capacity of the thin film 38, the requirement for the thickness of the thin film 38 can be reduced, and in the case of the same pressure bearing capacity of the sealing cover 14, the thickness of the thin film 38 can be greatly reduced to bear greater pressure with relatively smaller thickness.

[0044] In the embodiment, the outer contour of the sealing cover 14 is an irregular hexagon, and part of the side of the hexagon is a straight line and part is a curve. The side wall 40 is connected to the periphery of the thin film 38. Therefore, the outer contour of the sealing cover 14, i.e. the outer contour of the side wall 40, is an irregular hexagon, and the inner contour of the side wall 40 is in the same shape as the outer contour, and the inner contour of the side wall 40 is arranged in parallel with the outer contour.

[0045] In an optional example, the micro-electro-mechanical resonator 10 is formed by deep reactive ion etching a deep groove on the device layer 12 through silicon on insulator, forming the resonant body 16 through the deep groove, filling silicon oxide as a sacrificial layer on the device layer 12 and in the deep groove, and patterning to define the shape and position of the sealed cavity 22. The material of the sealing cover 14 is deposited on the sacrificial layer, and after the deposition is completed, the sacrificial layer is released by etching to form the side wall 40, the sealed cavity 22, and the support part and other structures. The sealing cover 14 is formed on the device layer 12 by a deposition process. Compared with a bonding process, the sealing cover 14 does not need to be additionally introduced into a bonding ring, which can reduce the space occupied by the sealing cover 14 on the device layer 12, and at the same time, it does not involve high temperature, avoiding the introduction of thermal stress to affect the performance of the micro-electro-mechanical resonator 10.

[0046] The micro-electro-mechanical resonator 10 further comprises a substrate 42 and a buried oxygen layer 44. The device layer 12 is spaced apart from the substrate 42, and the buried oxygen layer 44 is located between the device layer 12 and the substrate 42, thereby separating the two. The fixed area 20, as well as the anchor point 28 of the resonant body 16 and the electrode assembly 18, are connected to the substrate 42 through the buried oxygen layer 44. The opposite sides of the buried oxygen layer 44 are in sealing cooperation with the fixed area 20 of the device layer 12 and the substrate 42, respectively, and the side wall 40 of the sealing cover 14 is in sealing cooperation with the side of the fixed area 20 away from the buried oxygen layer 44, thereby forming a sealed space between the thin film 38 and the substrate 42. The resonant body 16 is located in the sealed space to reduce the influence of the air in the external environment on the performance of the micro-electro-mechanical resonator 10.

[0047] In an embodiment, the support part comprises a plurality of support columns 46 located in the sealed cavity 22. The plurality of support columns 46 are spaced apart from each other, and the support columns 46 are spaced apart from the side wall 40 by a certain distance. Each support column 46 is connected to the thin film 38 and the device layer 12, respectively, thereby forming a plurality of rigidly supported areas on the thin film 38 to further improve the pressure bearing capacity of the thin film 38.

[0048] The specific number of support columns 46 is not limited, and can be arranged according to the overhanging area of the thin film 38, as long as the sealing cover 14 will not be damaged by pressure in the subsequent processing process. For example, if the overhanging area of the thin film 38 relative to the device layer 12 is large and the strength is relatively low, a plurality of support columns 46 can be arranged in the sealing cavity 22 to achieve better support effect. If the overhanging area of the thin film 38 relative to the device layer 12 is small and the strength is relatively high, a small number of support columns 46 can be arranged in the sealing cavity 22 to avoid occupying too much space.

[0049] When the thin film 38 is deformed by pressure such as plastic packaging pressure during processing, the support column 46 supports the thin film 38 to hinder its deformation. The edge of the support column 46 on the thin film 38 forms a maximum stress position, and the position farthest from the support column 46 (i.e. the position between the two adjacent support columns 46) forms a maximum deformation position. The greater the distance between the two adjacent support columns 46, the greater the deformation of the maximum deformation position, and the greater the stress of the maximum stress position.

[0050] The thickness of the thin film 38 is 5 μm, the diameter of the end of the support column 46 connected to the thin film 38 is 40 μm, and the influence of different distances between the support columns 46 on the maximum stress on the thin film 38 under a plastic packaging pressure of 8 MPa is simulated based on a finite element software. The results are shown in FIG. 8, which shows that when the distance between the two adjacent support columns 46 increases, the maximum stress on the thin film 38 also increases. Figure 4

[0051] Preferably, the minimum distance between any two adjacent support columns 46 is less than or equal to 50 μm. Controlling the distance within this range can achieve better support effect and prevent the maximum stress on the thin film 38 from being too large, while avoiding the support columns 46 being too densely distributed, and taking into account the overall strength and the space occupied. In an optional example, the minimum distance between any two adjacent support columns 46 is 20-50 μm.

[0052] In an embodiment, the area of the end of the support column 46 connected to the thin film 38 is greater than the area of the end of the support column 46 connected to the device layer 12, so that the support column 46 has an inverted table structure. The inverted table structure can form an inclined surface with an acute angle with the device layer 12 on the side surface 52 of the support column 46. When the thin film 38 is deformed, the stress at the junction of the thin film 38 and the top edge of the support column 46 is the largest, and the stress at this position can be transmitted downward along the inclined surface of the support column 46, thereby dispersing the stress and reducing the maximum stress on the thin film 38 and the risk of damage.

[0053] ​The specific shape of the support column 46 is not limited, for example, the horizontal cross section of the support column 46 can be circular or irregular shape matching the inactive part of the device layer 12. In the embodiment, the horizontal cross section of the support column 46 is circular, i.e. the support column 46 is an inverted circular truncated cone.

[0054] The support column 46 includes a top surface 48 connected to the thin film 38, a bottom surface 50 connected to the device layer 12, and a side surface 52 connected between the top surface 48 and the bottom surface 50, the side surface 52 extends inwardly from the top surface 48 towards the bottom surface 50, so that the side surface 52 forms an inclined surface extending downwardly to disperse the pressure on the top edge of the support column 46. The minimum distance between the adjacent two support columns 46, i.e. the minimum distance between the edges of the top surfaces 48 of the adjacent two support columns 46.

[0055] In an optional example, the top surface 48 and the bottom surface 50 have the same shape, and the projection of the bottom surface 50 on the thin film 38 is located in the top surface 48 in the direction perpendicular to the top surface 48 and the bottom surface 50, and the centers of the top surface 48 and the bottom surface 50 coincide. Optionally, the top surface 48 and the bottom surface 50 are both circular, and the centers of the top surface 48 and the bottom surface 50 are both located on the central axis of the support column 46.

[0056] Figure 5 The simulation diagram of the relationship between the support column 46 with different inclination angles and the maximum stress on the thin film 38, the inclination angle of the support column 46 is the angle between the support column 46 and the device layer 12, from the diagram, it can be seen that the angle between the support column 46 and the device layer 12 is too large or too small, which will cause the stress on the thin film 38 to be large, and the greater the stress on the thin film 38, the higher the risk of damage.

[0057] Preferably, the angle α between the side surface 52 of the support column 46 and the surface of the device layer 12 close to the thin film 38 is 35°-50°, from Figure 5 It can be seen that when the angle α is in the range, the stress on the thin film 38 is relatively small, and the effect of the support column 46 on dispersing the stress is good. In an optional example, the angle α is close to 40°.

[0058] In an embodiment, a through hole is provided on the sealing cover 14, the through hole can be formed by etching, the through hole penetrates the thin film 38 and the support column 46 in sequence. A conductive member 54 is provided in the through hole, the conductive member 54 can be formed in the through hole by deposition, the conductive member 54 is electrically connected to the electrode assembly 18 and / or the resonant main body 16, so that the support column 46 and the conductive member 54 etched and deposited in the support column 46 can be used as a contact electrode, which is connected to the bonding pad on the edge of the chip through the metal wire above the sealing cover 14. Optionally, one support column 46 is provided on each electrode of the electrode assembly 18, and the electrodes of the electrode assembly 18 are electrically connected to the conductive member 54 in the support column 46.

[0059] The second embodiment of the present application provides a micro-electro-mechanical resonator, which is mainly different from the micro-electro-mechanical resonator in the first embodiment in that:

[0060] Please refer to Figure 6 In the embodiment, the side of the sealing cover 14 away from the device layer 12 is provided with a reinforcing layer, which can further enhance the pressure bearing capacity of the area above the sealing cavity 22.

[0061] The reinforcing layer can be a multi-layer structure or a single-layer structure. In the embodiment, the reinforcing layer comprises a first reinforcing layer 56 deposited on the top of the sealing cover 14 and a second reinforcing layer 58 coated on the top of the first reinforcing layer 56, which can reduce the air leakage rate of the sealing cavity 22 while enhancing the pressure bearing capacity.

[0062] The first reinforcing layer 56 can be made of silicon, germanium, silicon nitride, silicon carbide or the like, and the thickness of the first reinforcing layer 56 is greater than or equal to 1 μm. The second reinforcing layer 58 can be made of a structural adhesive material such as low-temperature curing epoxy resin adhesive (such as LTC9000), high-aspect-ratio photoresist (such as HARE-SQ), negative epoxy-based photoresist (such as SU-8) or the like, and the thickness of the second reinforcing layer 58 is greater than or equal to 10 μm.

[0063] In other embodiments, the second reinforcing layer 58 can be coated on the top of the sealing cover 14 first, and then the first reinforcing layer 56 can be plated on the second reinforcing layer 58.

[0064] The third embodiment of the present application provides a micro-electro-mechanical resonator, which is mainly different from the micro-electro-mechanical resonator in the second embodiment in that:

[0065] Please refer to Figure 7 In the embodiment, the thin film 38 is provided with a release hole 60 penetrating therethrough, which is used for releasing the sacrificial layer to form the sealing cavity 22. Optionally, the release hole 60 is formed by etching.

[0066] The spacing between the release hole 60 and the adjacent support column 46 is 3-10 μm, and the edge of the support column 46 and the junction of the thin film 38 are the maximum stress positions. The minimum spacing between the adjacent two support columns 46 is less than or equal to 50 μm, the middle position between the two support columns 46 is the maximum deformation position, and the position close to the support column 46 has smaller deformation. Controlling the spacing between the release hole 60 and the support column 46 to be 3-10 μm can make the release hole 60 avoid the maximum stress position and be at a position with smaller deformation, thereby reducing the influence of the release hole 60 on the pressure bearing capacity of the thin film 38.

[0067] The fourth embodiment of the present application provides a micro-electro-mechanical resonator, which is mainly different from the micro-electro-mechanical resonator in the first embodiment in that:

[0068] Please refer to Figure 8 In the embodiment, the thin film 38 has a large size, and the distance between the support column 46 serving as the contact electrode and the side wall 40 is greater than 50 μm. When the pressure of the subsequent process is applied, the thin film 38 at the edge is at risk of being broken. In the embodiment, other support columns 46 are arranged between the support column 46 serving as the contact electrode and the side wall 40, and the support columns 46 only serve to support the thin film 38. The diameter of the support columns 46 is greater than or equal to 10 μm, and the distance between the support columns 46 and the side wall 40 is less than or equal to 50 μm. The limited area is used to increase the pressure resistance of the enlarged sealing cavity.

[0069] The fifth embodiment of the application provides a micro-electro-mechanical resonator. The main difference between the micro-electro-mechanical resonator and the micro-electro-mechanical resonator in the first embodiment is that:

[0070] Please refer to Figure 9 In the embodiment, the support part includes two support blocks 62 connected to the side wall 40. The thin film 38, the side wall 40, and the support part form the sealing cavity 22. The two support blocks 62 are connected to opposite sides of the side wall 40, respectively. Each support block 62 extends from the side wall 40 to between the adjacent two vibration arm units 29 of the different vibration arms 24. The two support blocks 62 are located on opposite sides of the beam structure 26. The shape of the sealing cavity 22 is adapted to the shape of the resonant body 16. The sealing cavity 22 covers the resonant body 16, and the electrode assembly 18 is located outside the sealing cavity 22. Optionally, the resonant body 16 is H-shaped, and the shape of the sealing cavity 22 is also H-shaped. By arranging the two support blocks 62 extending to the adjacent vibration arm units 29, the shape of the sealing cavity 22 is adapted to the shape of the resonant body 16. The size of the sealing cavity 22 is slightly larger than that of the resonant body 16. Therefore, the sealing cavity 22 can cover the resonant body 16, and the electrode assembly 18 and the fixed region 20 are located outside the sealing cavity 22. In the case of reducing the air damping loss of the micro-electro-mechanical resonator 10, the shape of the sealing cavity 22 is adapted to the shape of the resonant body 16 by arranging the support blocks 62. The volume of the sealing cavity 22 is reduced to improve the pressure bearing capacity of the thin film 38.

[0071] Optionally, the distance between the two inner walls of the sealing cavity 22 on opposite sides of the vibration arm unit 29 is less than or equal to 50 μm, so that the thin film 38 has a better pressure bearing effect.

[0072] It should be noted that each of the top views in the drawings of the present application shows the resonant body, the electrode assembly and other devices, and in actual products, the resonant body, the electrode assembly and other devices are located in the interior of the micro-electromechanical resonator, and the resonant body, the electrode assembly and other devices can not be directly observed through the sealing cover. The resonant body, the electrode assembly and other devices are shown in the top view to facilitate understanding of the technical solutions of the present application.

[0073] The above-described embodiments are merely preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and replacements made by those skilled in the art on the basis of the present application all belong to the scope of protection of the present application.

Claims

1. A micro-electromechanical resonant device, characterized in that: comprising a device layer and a sealing cover arranged in a stacked manner; The device layer includes a resonant body, an electrode assembly arranged corresponding to the resonant body, and a fixed area spaced apart from the resonant body; The sealing cover includes a film, a side wall connected to the periphery of the film, and a support portion located inside the side wall, wherein the side wall and the film together form a sealed cavity, or the side wall, the film, and the support portion together form a sealed cavity, and the sealed cavity at least covers the resonant body; The two ends of the side wall are sealed to the film and the fixed area respectively, one end of the support part is connected to the film, and the other end is connected to the electrode assembly and / or the fixed area in the device layer to limit the overhanging size of the film sealing cavity.

2. The micro-electromechanical resonant device according to claim 1, wherein: The support portion includes a plurality of support columns disposed in the sealed cavity and spaced apart from the sidewalls, wherein the area of ​​one end of each support column connected to the film is larger than the area of ​​one end of the support column connected to the device layer.

3. The micro-electromechanical resonant device according to claim 2, wherein: The support column includes a top surface connected to the film, a bottom surface connected to the device layer, and a side surface connected between the top surface and the bottom surface, and the side surface extends inwardly from the top surface toward the bottom surface.

4. The micro-electromechanical resonant device according to claim 3, wherein: The top surface and the bottom surface have the same shape, along a direction perpendicular to the top surface and the bottom surface, a projection of the bottom surface on the film is located inside the top surface, and the centers of the top surface and the bottom surface coincide with each other.

5. The micro-electromechanical resonant device according to claim 3, wherein: The angle between the side surface and the surface of the device layer facing the film is 35° to 50°.

6. The micro-electromechanical resonant device according to claim 2, wherein: The minimum distance between any two adjacent support pillars is less than or equal to 50 μm.

7. The micro-electromechanical resonant device according to claim 6, wherein: The film is penetrated by a release hole, and the distance between the release hole and the adjacent support column is 3 to 10 μm.

8. The micro-electromechanical resonant device according to claim 2, wherein: The sealing cover is provided with a through hole, which passes through the film and the support column in sequence. A conductive member is provided in the through hole, and the conductive member is electrically connected to the electrode assembly and / or the resonant body.

9. The micro-electromechanical resonant device according to claim 1, wherein: The resonant body includes two vibration arms arranged opposite to each other at an interval, a beam structure and an anchor point located between the two vibration arms, and the anchor point is connected to the vibration arms through the beam structure; Each of the vibration arms includes two vibration arm monomers, and the supporting part includes two support blocks connected to the side wall. The support block extends from the side wall to between two adjacent vibration arm monomers of different vibration arms. The two support blocks are respectively located on opposite sides of the beam structure. The shape of the sealed cavity is adapted to the shape of the resonant body. The sealed cavity covers the resonant body, and the electrode assembly is located outside the sealed cavity.

10. The micro-electromechanical resonant device according to claim 9, characterized in that: The distance between the two inner walls of the sealed cavity on opposite sides of the vibration arm unit is less than or equal to 50 μm.

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