MEMS microphone and its micro-electromechanical structure

Abstract

The present application discloses a MEMS microphone and its micro-electromechanical structure. The micro-electromechanical structure includes: a back plate; a vibrating membrane having at least one through hole and constituting a variable capacitor with the back plate; at least one connecting column, one end of each connecting column being fixedly connected to the back plate; and at least one movable structure, each of which is located in a corresponding through hole to be separated from the vibrating membrane, and each movable structure is fixedly connected to the other end of the corresponding connecting column, wherein the gap between the movable structure and the through hole is used for gas circulation. The micro-electromechanical structure is provided with a movable structure separated from the vibrating membrane in the through hole of the vibrating membrane, so that there is a gap between the movable structure and the through hole, so that the air leakage of the micro-electromechanical structure adapts to different external sound pressures, thereby improving the problem of large deformation of the vibrating membrane while ensuring the performance of the MEMS microphone.

Description

Technical Field

[0001] The present application relates to the field of semiconductor device manufacturing, and more specifically, to a MEMS microphone and a micro-electromechanical structure thereof. Background Art

[0002] Microphones manufactured based on micro-electromechanical systems (MEMS) are called MEMS microphones, which usually include a micro-electromechanical structure and a functional integrated circuit (Application Specific Integrated Circuit, ASIC) chip electrically connected to it.

[0003] In traditional MEMS microphones, in order to ensure the low-frequency response performance of the MEMS microphone, a small-sized through-hole structure is usually opened on the vibration membrane of the micro-electromechanical structure as a gas flow channel. When the external sound pressure (air pressure) is high, the gas acting on the vibration membrane does not have time to completely escape through the small-sized through-hole structure, causing a large deformation of the vibration membrane, and ultimately causing the MEMS microphone to fail.

[0004] In the prior art, the vibration membrane is thickened or the material of the vibration membrane is optimized to increase the stress that the vibration membrane can withstand, thereby reducing the deformation of the vibration membrane. However, changing the thickness or material of the vibration membrane will affect the sensitivity of the micro-electromechanical structure, thereby reducing the performance of the MEMS microphone.

[0005] Therefore, it is hoped to provide an improved MEMS microphone and a micro-electromechanical structure thereof, so as to improve the problem of large deformation of the diaphragm while ensuring the performance of the MEMS microphone. Summary of the invention

[0006] In view of this, the present invention provides an improved MEMS microphone and its micro-electromechanical structure, by disposing a movable structure separated from the vibration membrane in the through hole of the vibration membrane, so that there is a gap between the movable structure and the through hole, so that the air leakage of the micro-electromechanical structure can adapt to different external sound pressures, thereby ensuring the performance of the MEMS microphone while improving the problem of large deformation of the vibration membrane.

[0007] According to one aspect of an embodiment of the present invention, a micro-electromechanical structure is provided, comprising: a back plate; a vibration membrane having at least one through hole and constituting a variable capacitor with the back plate; at least one connecting column, one end of each of the connecting columns being fixedly connected to the back plate; and at least one movable structure, each of which is located in the corresponding through hole to be separated from the vibration membrane, and each of the movable structures is fixedly connected to the other end of the corresponding connecting column, wherein the gap between the movable structure and the through hole is used for gas circulation.

[0008] Preferably, the at least one movable structure includes the movable structure in the shape of a cylinder and / or the movable structure in the shape of a polygonal column, wherein the shape of the movable structure matches the through hole.

[0009] Preferably, the at least one movable structure includes the movable structure in the shape of a cylinder and / or the movable structure in the shape of a polygonal column, and the movable structure includes at least one groove and / or at least one air relief groove, the at least one groove extends radially inward from the cylindrical surface of the movable structure, and the at least one groove passes through the top and bottom surfaces of the movable structure; the at least one air relief groove passes through the top and bottom surfaces of the movable structure.

[0010] Preferably, there are a plurality of grooves, and the openings of the plurality of grooves are evenly distributed along the outer peripheral edge of the movable structure.

[0011] Preferably, there are a plurality of the air relief grooves, and the plurality of the air relief grooves surround the center of the movable structure and are separated from each other.

[0012] Preferably, the movable structure comprises a plurality of the air relief grooves and a plurality of the grooves, and the number of the air relief grooves is the same as the number of the grooves.

[0013] The openings of the plurality of grooves are evenly distributed along the outer peripheral edge of the movable structure, the plurality of air relief grooves surround the center of the movable structure, and each of the air relief grooves is located between two adjacent grooves and is separated from the grooves.

[0014] Preferably, the center of each movable structure is connected to the corresponding connecting column.

[0015] Preferably, the back plate has a plurality of air leakage holes, and the orthographic projection of at least one air leakage hole falls within the orthographic projection of the movable structure.

[0016] Preferably, the insulating layer is connected to the connecting column; and the conductive layer is located on the insulating layer, wherein at least one of the air leakage holes penetrates the insulating layer and the conductive layer.

[0017] Preferably, the back plate includes: a fixed part, which is fixedly connected to the vibration membrane via a supporting structure; at least one connecting part, which is separated from the fixed part and fixedly connected to the corresponding connecting column; and a beam structure, which connects the fixed part and the connecting part, wherein an air flow channel is provided between the fixed part, the connecting part and the beam structure.

[0018] Preferably, the beam structure comprises a bent beam and / or a cantilever beam.

[0019] Preferably, the connecting portion corresponds to the center of the movable structure, wherein two ends of the connecting column respectively connect the center of the connecting portion and the center of the movable structure.

[0020] Preferably, the orthographic projection of the connecting portion falls within the orthographic projection of the movable structure; or the orthographic projection of the movable structure falls within the orthographic projection of the connecting portion; or the orthographic projection of the movable structure coincides with the orthographic projection of the connecting portion.

[0021] Preferably, the connecting portion has at least one air leakage hole, and the at least one air leakage hole surrounds the center of the connecting portion.

[0022] According to another aspect of the embodiments of the present invention, a MEMS microphone is provided, comprising the micro-electromechanical structure as described above.

[0023] According to the MEMS microphone and its micro-electromechanical structure provided by the embodiments of the present invention, a movable structure separated from the vibrating membrane is arranged in the through hole of the vibrating membrane, so that there is a gap between the movable structure and the through hole, and the gap is used as a gas leakage channel. When the external sound pressure is low, the gas acting on the vibrating membrane can be directly discharged through the gap. When the external sound pressure is high, the movable structure is deformed, so that the gap between the movable structure and the through hole becomes larger, thereby accelerating the speed of gas discharge through the gap, so that the gas leakage amount of the micro-electromechanical structure adapts to different external sound pressures, thereby improving the problem of large deformation of the vibrating membrane while ensuring the low-frequency response characteristics and sensitivity of the MEMS microphone.

[0024] Furthermore, by setting the movable structure to be a cylinder or a polygonal prism and matching the shape of the movable structure with the through hole, the gap between the movable structure and the through hole is distributed more evenly, so that the gas is dispersed more evenly when passing through the gap, further improving the problem of large deformation of the vibration membrane.

[0025] Furthermore, by providing grooves and / or air release grooves in the movable structure, not only the length of the air release channel is increased, but also the rigidity of the movable structure is reduced, making the movable structure more susceptible to deformation when the external sound pressure is high.

[0026] Furthermore, by connecting the center of the movable structure with the connecting column, the edges of the movable structure are all free ends and are evenly stressed, which is more conducive to the movable structure expanding the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0027] Furthermore, by arranging a plurality of air leakage holes on the back plate and aligning the position of at least one air leakage hole with the movable structure, when the external sound pressure is high, the gas can directly reach the movable structure through the air leakage holes, which is more conducive to the movable structure to expand the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0028] Furthermore, by arranging a beam structure on the back plate, an air flow channel is provided between the fixed part, the connecting part and the beam structure of the back plate. The position of the air flow channel corresponds to the movable structure. When the external sound pressure is high, the gas can directly reach the movable structure through the air flow channel, which is more conducive to the movable structure to expand the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0029] Therefore, the MEMS microphone and its micro-electromechanical structure provided by the present invention can improve the air release capacity of the vibration membrane and the back plate under high external sound pressure conditions through a movable structure, thereby achieving the purpose of improving the reliability of the MEMS microphone, reducing costs, and thus being used for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, rather than limiting the present application.

[0031] Figure 1 A first stereoscopic view of a micro-electromechanical structure according to a first embodiment of the present invention is shown.

[0032] Figure 2 Shows Figure 1 An enlarged schematic diagram of the local structure.

[0033] Figure 3 A second perspective view of the micro-electromechanical structure according to the first embodiment of the present invention is shown.

[0034] Figure 4 Shows Figure 3 Schematic diagram of the structure of the vibration membrane.

[0035] Figures 5a to 8b The diagram shows the structure of movable structures of various shapes and the air leakage channels formed by the movable structures of various shapes and the through holes of the vibration membrane in the first embodiment of the present invention.

[0036] Fig. 9 A perspective view of a micro-electromechanical structure according to a second embodiment of the present invention is shown.

[0037] Fig.10 A perspective view of a micro-electromechanical structure according to a third embodiment of the present invention is shown.

[0038] Fig.11Shows Fig.10 Top view of the mid-back panel.

[0039] Fig.12 Shows Fig.11 An enlarged schematic diagram of the local structure.

[0040] Fig.13 A perspective view of a micro-electromechanical structure according to a fourth embodiment of the present invention is shown.

[0041] Fig.14 Shows Fig.13 Top view of the mid-back panel.

[0042] Fig.15 Shows Fig.14 An enlarged schematic diagram of the local structure.

[0043] Fig.16 A perspective view of a micro-electromechanical structure according to a fifth embodiment of the present invention is shown.

[0044] Fig.17 Shows Fig.16 Top view of the mid-back panel.

[0045] Fig.18 A perspective view of a micro-electromechanical structure according to a sixth embodiment of the present invention is shown.

[0046] Fig.19 Shows Fig.18 Top view of the mid-back panel.

[0047] Fig. 20 A schematic structural diagram of a MEMS microphone according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown. For the sake of simplicity, the semiconductor structure obtained after several steps can be described in one figure.

[0049] It should be understood that when describing the structure of a device, when a layer or a region is referred to as being "on" or "over" another layer or another region, it may mean that it is directly on the other layer or another region, or that other layers or regions are included between it and the other layer or another region. Furthermore, if the device is turned over, the layer or a region will be "below" or "beneath" another layer or another region.

[0050] If the purpose is to describe the situation of being directly on another layer or another area, this article will use expressions such as "directly on..." or "on... and adjacent to...".

[0051] Many specific details of the present invention are described below, such as device structure, materials, dimensions, processing technology and techniques, so as to more clearly understand the present invention. However, as those skilled in the art will appreciate, the present invention may be implemented without following these specific details.

[0052] The present invention may be embodied in various forms, some examples of which will be described below.

[0053] Figure 1 A first stereogram of a micro-electromechanical structure according to a first embodiment of the present invention is shown, Figure 2 Shows Figure 1 An enlarged schematic diagram of the local structure in Figure 3 A second stereoscopic view of the micro-electromechanical structure of the first embodiment of the present invention is shown, Figure 4 Shows Figure 3 Schematic diagram of the structure of the vibration membrane.

[0054] like Figures 1 to 4 As shown, the micro-electromechanical structure of the first embodiment of the present invention includes: a vibrating membrane 110, a back plate 120, a movable structure 130 and a connecting column 140. The vibrating membrane 110 has at least one through hole 1101, and the vibrating membrane 110 and the back plate 120 constitute a variable capacitor. The number of movable structures 130 is one or more, and each movable structure 130 is respectively located in a corresponding through hole 1101 to be separated from the vibrating membrane 110, wherein the gap between the movable structure 130 and the through hole 1101 is used for gas circulation. The number of connecting columns 140 is one or more, and one end of each connecting column 140 is fixedly connected to the back plate 120, and the other end is fixedly connected to the corresponding movable structure 130. Preferably, the center of each movable structure 130 is connected to the corresponding connecting column 140. Among them, the material of the vibrating membrane 110 includes polysilicon, the material of the connecting column 140 includes silicon nitride or silicon oxide, and the thickness range of the movable structure 130 includes 0.3 to 3μm. However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for the materials of the vibration membrane 110 and the connection column 140 and the thickness of the movable structure 130 as needed.

[0055] In this embodiment, the micro-electromechanical structure further includes: two pads 160, a substrate 101, a first support structure 102, and a second support structure 103. Each pad 160 is located on the back plate 120, one of which is electrically connected to the back plate 120, and the other is electrically connected to the vibration membrane 110. The first support structure 102 is the portion left on the substrate 101 after the sacrificial layer is released. The first support structure 102 is located on the peripheral edge of the substrate 101, and the vibration membrane 110 located above the first support structure 102 is supported on the substrate 101 by a fully fixed peripheral edge method. A microphone back cavity 1011 is formed between the substrate 101 and the vibration membrane 110. The second support structure 103 is the portion left on the vibration membrane 110 after the sacrificial layer is released. The position of the second support structure 103 corresponds to the first support structure 102. The second support structure 103 is located on the peripheral edge of the vibration membrane 110. The back plate 120 located above the second support structure 103 is supported on the substrate 101 and the vibration membrane 110 by a fully fixed peripheral edge method, so that the portion of the back plate 120 that is not in contact with the second support structure 103 is separated from the vibration membrane 110 by a preset distance. Among them, the materials of the first support structure 102 and the second support structure 103 include silicon oxide. However, the embodiment of the present invention is not limited to this, and those skilled in the art can make other settings for the materials of the first support structure 102 and the second support structure 103 and the support and fixing method between the substrate 101, the vibration membrane 110, and the back plate 120 as needed.

[0056] In this embodiment, the back plate 120 includes an insulating layer 121 and a conductive layer 122, the insulating layer 121 is fixed on the second support structure 103 and connected to the connecting column 140, and the conductive layer 122 is located on the insulating layer 121. The size of the conductive layer 122 is smaller than that of the insulating layer 121, and the conductive layer 122 corresponds to the portion of the back plate 120 that is not in contact with the second support structure 103. The material of the insulating layer 121 includes silicon nitride, and the material of the conductive layer 122 includes polycrystalline silicon. The back plate 120 has a plurality of sound inlet holes 1201, each of which passes through the insulating layer 121 and the conductive layer 122, and is used to allow the sound pressure signal to reach the vibrating membrane 110 through the plurality of sound inlet holes 1201. However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the structure and material of the back plate 120 as needed.

[0057] In some preferred embodiments, the micro-electromechanical structure further includes a plurality of protruding structures 150 , which are located on a side of the back plate 120 facing the vibration membrane 110 , and are used to prevent the vibration membrane 110 from adhering to the back plate 120 .

[0058] The movable structure 130 includes a cylindrical movable structure and / or a polygonal movable structure. In some preferred embodiments, the shape of the movable structure 130 matches the through hole 1101. Figures 5a to 8b The cylindrical movable structure 130 will be described in detail.

[0059] The movable structure 130 is a complete cylinder, and the radius of the cylinder ranges from 0 to 100 μm. Figure 5a The movable structure 130 is placed in the through hole 1101 of the vibration membrane 110, as shown. Figure 5b As shown, the gap between the movable structure 130 and the through hole 1101 is annular, and the gap can be used as an air leakage channel. The gap width d1 ranges from 0 to 5 μm, and the circumference of the annular air leakage channel ranges from 10 to 100 μm. In some other embodiments, when the movable structure 130 is a movable structure in the form of a polygonal prism, the side length of the polygonal prism ranges from 0 to 100 μm.

[0060] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for parameters such as the size of the movable structure 130 and the width of the gap as needed.

[0061] like Figure 6a As shown, the movable structure 130 may also be composed of a cylinder and one or more grooves 1301. The grooves 1301 extend radially inward from the cylindrical surface of the movable structure 130, and the grooves 1301 penetrate the top surface and the bottom surface of the movable structure 130.

[0062] In some preferred embodiments, there are multiple grooves 1301, and the openings of the multiple grooves 1301 are evenly distributed along the outer periphery of the movable structure 130. Figure 6a FIG. 1 shows a case where the number of grooves 1301 is 4. The 4 grooves 1301 change the cylinder into a cylinder composed of 4 sectors. The movable structure 130 is placed in the through hole 1101 of the vibration membrane 110. Figure 6b As shown, the gap between the movable structure 130 and the through hole 1101 is annular, and the gap is connected with the groove 1301 and can serve as a gas release channel. The width d2 of the groove 1301 can be consistent with the width d1 of the gap.

[0063] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for parameters such as the number, distribution, and width of the grooves 1301 as needed.

[0064] like Figure 7a As shown, the movable structure 130 may also be composed of a cylinder and one or more air relief grooves 1302. The air relief grooves 1302 surround the center of the movable structure 130 and penetrate the top surface and the bottom surface of the movable structure 130.

[0065] In some preferred embodiments, there are multiple air release grooves 1302, and the multiple air release grooves 1302 are evenly distributed around the center of the movable structure 130. Figure 7a FIG. 1 shows a case where there are four air release grooves 1302. The four air release grooves 1302 are all arc-shaped grooves, and each air release groove 1302 is separated from each other. The movable structure 130 is placed in the through hole 1101 of the vibration membrane 110. Figure 7b As shown, the gap between the movable structure 130 and the through hole 1101 is annular, and the gap and the air release groove 1302 can serve as an air release channel together. The width d3 of the air release groove 1302 can be consistent with the gap width d1, and the length range of each air release groove 1302 includes 1 to 50 microns.

[0066] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for the number, distribution, width and other parameters of the air release grooves 1302 as needed.

[0067] like Figure 8a As shown, the movable structure 130 can also be composed of a cylinder and one or more grooves 1301 and one or more air release grooves 1302. The structures of the grooves 1301 and the air release grooves 1302 can refer to Figures 6a to 7b The description is not repeated here. Figure 8a 1 shows a case where the number of the air release grooves 1302 is the same as the number of the grooves 1301 and both are 4. Each air release groove 1302 is located between two adjacent grooves 1301 and is separated from the adjacent grooves 1301. The movable structure 130 is placed in the through hole 1101 of the vibration membrane 110, as shown in FIG. Figure 8b As shown, the gap between the movable structure 130 and the through hole 1101 is in a circular ring shape, and the gap, the groove 1301 and the air release groove 1302 can serve as an air release channel together.

[0068] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for the number, distribution and other parameters of the grooves 1301 and the air release grooves 1302 as needed.

[0069] Fig. 9 A perspective view of a micro-electromechanical structure according to a second embodiment of the present invention is shown.

[0070] like Fig. 9 As shown, the micro-electromechanical structure of the second embodiment of the present invention includes: a vibration membrane 110, a back plate 120, a movable structure 130, a connecting column 140, a pad 160, a substrate 101, a first supporting structure 102 and a second supporting structure 103, preferably, it also includes a protruding structure (not shown). The micro-electromechanical structure of this embodiment is generally consistent with that of the first embodiment, and can be referred to Figures 1 to 8b The description is not repeated here.

[0071] The difference from the first embodiment is that the back plate 120 of this embodiment further includes one or more air leakage holes 1202 passing through the insulating layer 121 and the conductive layer 122. The position of the air leakage hole 1202 corresponds to the movable structure 130, that is, the orthographic projection of the air leakage hole 1202 falls within the orthographic projection of the movable structure 130. In some specific embodiments, each movable structure 130 corresponds to four air leakage holes 1202, and the four air leakage holes 1202 are evenly distributed around the connecting column 140.

[0072] In some other embodiments, the number of the air leakage holes 1202 may also include 8 or 12, and the air leakage holes have two sizes and are evenly distributed around the connecting column 140. When each movable structure 130 corresponds to 8 air leakage holes, the air leakage holes of two sizes are alternately distributed, and when each movable structure 130 corresponds to 12 air leakage holes, two air leakage holes of smaller sizes are arranged between two adjacent air leakage holes of larger sizes.

[0073] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the number, size, and distribution of the air leakage holes 1202 as needed.

[0074] Fig.10 A three-dimensional diagram of a micro-electromechanical structure according to a third embodiment of the present invention is shown. Fig.11 Shows Fig.10 Top view of the mid-back panel. Fig.12 Shows Fig.11 An enlarged schematic diagram of the local structure.

[0075] like Figures 10 to 12 As shown, the micro-electromechanical structure of the third embodiment of the present invention includes: a vibration membrane 110, a back plate 120, a movable structure 130, a connecting column 140, a pad 160, a substrate 101, a first supporting structure 102 and a second supporting structure 103, preferably, it also includes a protruding structure (not shown). The micro-electromechanical structure of this embodiment is generally consistent with the first embodiment, and can be referred to Figures 1 to 8b The description is not repeated here.

[0076] The difference from the first embodiment is that the back plate 120 of this embodiment is divided into a fixed portion 120a, one or more connecting portions 120b and a beam structure, and in this embodiment, the beam structure is a bending beam 120c. The fixed portion 120a is fixedly connected to the vibration membrane 110 via the second supporting structure 103. The connecting portion 120b is separated from the fixed portion 120a and fixedly connected to the corresponding connecting column 140. The bending beam 120c connects the fixed portion 120a and the connecting portion 120b, wherein an air flow channel 1204 is provided between the fixed portion 120a, the connecting portion 120b and the bending beam 120c.

[0077] In this embodiment, the connection portion 120b corresponds to the center of the movable structure 130, wherein the two ends of the connection column 140 respectively connect the center of the connection portion 120b and the center of the movable structure 130, and each movable structure corresponds to no less than two bending beams 120c. The orthographic projection of the connection portion 120b falls within the orthographic projection of the movable structure 130. In some other embodiments, the orthographic projection of the movable structure 130 falls within the orthographic projection of the connection portion 120b; or the orthographic projection of the movable structure 130 coincides with the orthographic projection of the connection portion 120b. In this embodiment, the length range of the bending beam 120c includes 5 to 100 μm, the width range of the bending beam 120c includes 1 to 50 μm, and the number of folds of the bending beam 120c includes 1 to 10 times.

[0078] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other settings for the number, size, and bending times of the bent beams 120c corresponding to each connecting portion 120b as needed.

[0079] Fig.13 A perspective view of a micro-electromechanical structure according to a fourth embodiment of the present invention is shown. Fig.14 Shows Fig.13 Top view of the mid-back panel. Fig.15 Shows Fig.14 An enlarged schematic diagram of the local structure.

[0080] like Figures 13 to 15 As shown, the micro-electromechanical structure of the fourth embodiment of the present invention includes: a vibration membrane 110, a back plate 120, a movable structure 130, a connecting column 140, a pad 160, a substrate 101, a first supporting structure 102 and a second supporting structure 103, preferably, also includes a protruding structure (not shown). The micro-electromechanical structure of this embodiment is generally consistent with the fourth embodiment, and will not be repeated here.

[0081] The difference from the third embodiment is that the back plate 120 of this embodiment is not only divided into a fixed portion 120a, one or more connecting portions 120b and a bending beam 120c, but each connecting portion 120b also has one or more air leakage holes 1205. In some specific embodiments, the number of the air leakage holes 1205 is multiple (for example, 6) and surrounds the center of the connecting portion 120b. In this embodiment, the gas can directly reach the movable structure 130 through the air flow channel 1204 and the air leakage holes 1205.

[0082] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the number and distribution of the air leakage holes 1205 as required.

[0083] Fig.16 A perspective view of a micro-electromechanical structure according to a fifth embodiment of the present invention is shown. Fig.17 Shows Fig.16 Top view of the mid-back panel.

[0084] like Figure 16 to Figure 17 As shown, the micro-electromechanical structure of the fifth embodiment of the present invention includes: a vibration membrane 110, a back plate 120, a movable structure 130, a connecting column 140, a pad 160, a substrate 101, a first supporting structure 102 and a second supporting structure 103, preferably, it also includes a protruding structure (not shown). The micro-electromechanical structure of this embodiment is generally consistent with the first embodiment, and can be referred to Figures 1 to 8b The description is not repeated here.

[0085] The difference from the first embodiment is that the back plate 120 of this embodiment is divided into a fixed portion 120a, one or more connecting portions 120b and a beam structure, and in this embodiment, the beam structure is a cantilever beam 120d. The fixed portion 120a is fixedly connected to the vibration membrane 110 via the second supporting structure 103. The connecting portion 120b is separated from the fixed portion 120a and fixedly connected to the corresponding connecting column 140. The cantilever beam 120d connects the fixed portion 120a and the connecting portion 120b, wherein an air flow channel 1206 is provided between the fixed portion 120a, the connecting portion 120b and the cantilever beam 120d.

[0086] In this embodiment, the connection portion 120b corresponds to the center of the movable structure 130, wherein the two ends of the connection column 140 respectively connect the center of the connection portion 120b and the center of the movable structure 130, and each movable structure corresponds to at least two cantilever beams 120d. The orthographic projection of the connection portion 120b falls within the orthographic projection of the movable structure 130. In some other embodiments, the orthographic projection of the movable structure 130 falls within the orthographic projection of the connection portion 120b; or the orthographic projection of the movable structure 130 coincides with the orthographic projection of the connection portion 120b. In this embodiment, the length range of the cantilever beam 120d includes 1 to 50 μm, and the width range includes 1 to 50 μm.

[0087] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the number and size of the cantilever beams 120d corresponding to each connecting portion 120b as required.

[0088] Fig.18 A perspective view of a micro-electromechanical structure according to a sixth embodiment of the present invention is shown. Fig.19 Shows Fig.18 Top view of the mid-back panel.

[0089] like Figure 18 to Figure 19As shown, the micro-electromechanical structure of the sixth embodiment of the present invention includes: a vibration membrane 110, a back plate 120, a movable structure 130, a connecting column 140, a pad 160, a substrate 101, a first supporting structure 102 and a second supporting structure 103, preferably, also includes a protruding structure (not shown). The micro-electromechanical structure of this embodiment is generally consistent with the fifth embodiment, and will not be repeated here.

[0090] The difference from the fifth embodiment is that the back plate 120 of this embodiment is not only divided into a fixed portion 120a, one or more connecting portions 120b and a cantilever beam 120d, but each connecting portion 120b also has one or more air leakage holes 1207. In some specific embodiments, the number of air leakage holes 1207 is multiple (for example, 4) and surrounds the center of the connecting portion 120b. In this embodiment, the gas can directly reach the movable structure 130 through the air flow channel 1206 and the air leakage holes 1207.

[0091] However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the number and distribution of the air leakage holes 1207 as required.

[0092] Fig. 20 A schematic structural diagram of a MEMS microphone according to an embodiment of the present invention is shown.

[0093] like Fig. 20 As shown, the MEMS microphone includes: a micro-electromechanical structure 100, a chip structure 200, a substrate 300, and a housing 400. The substrate 300 and the housing 400 serve as the packaging structure of the device. The micro-electromechanical structure 100 of the embodiment of the present invention can be selected from the six embodiments listed above, the chip structure 200 is, for example, an ASIC chip, and the substrate 300 is, for example, a lead frame or a PCB circuit board.

[0094] In this embodiment, the MEMS structure 100 and the chip structure 200 are electrically connected via the pad 160 , and the substrate 300 and the housing 400 of the package structure are used to form a receiving cavity of the package structure, and the MEMS structure 100 and the chip structure 200 are located in the receiving cavity.

[0095] According to the MEMS microphone and its micro-electromechanical structure provided by the embodiments of the present invention, a movable structure separated from the vibrating membrane is arranged in the through hole of the vibrating membrane, so that there is a gap between the movable structure and the through hole, and the gap is used as a gas leakage channel. When the external sound pressure is low, the gas acting on the vibrating membrane can be directly discharged through the gap. When the external sound pressure is high, the movable structure is deformed, so that the gap between the movable structure and the through hole becomes larger, thereby accelerating the speed of gas discharge through the gap, so that the gas leakage amount of the micro-electromechanical structure adapts to different external sound pressures, thereby improving the problem of large deformation of the vibrating membrane while ensuring the low-frequency response characteristics and sensitivity of the MEMS microphone.

[0096] Furthermore, by setting the movable structure to be a cylinder or a polygonal prism and matching the shape of the movable structure with the through hole, the gap between the movable structure and the through hole is distributed more evenly, so that the gas is dispersed more evenly when passing through the gap, further improving the problem of large deformation of the vibration membrane.

[0097] Furthermore, by providing grooves and / or air release grooves in the movable structure, not only the length of the air release channel is increased, but also the rigidity of the movable structure is reduced, making the movable structure more susceptible to deformation when the external sound pressure is high.

[0098] Furthermore, by connecting the center of the movable structure with the connecting column, the edges of the movable structure are all free ends and are evenly stressed, which is more conducive to the movable structure expanding the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0099] Furthermore, by arranging a plurality of air leakage holes on the back plate and aligning the position of at least one air leakage hole with the movable structure, when the external sound pressure is high, the gas can directly reach the movable structure through the air leakage holes, which is more conducive to the movable structure to expand the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0100] Furthermore, by arranging a beam structure on the back plate, an air flow channel is provided between the fixed part, the connecting part and the beam structure of the back plate. The position of the air flow channel corresponds to the movable structure. When the external sound pressure is high, the gas can directly reach the movable structure through the air flow channel, which is more conducive to the movable structure to expand the air leakage channel through deformation, thereby further improving the problem of large deformation of the vibration membrane.

[0101] Therefore, the MEMS microphone and its micro-electromechanical structure provided by the present invention can improve the air release capacity of the vibration membrane and the back plate under high external sound pressure conditions through a movable structure, thereby achieving the purpose of improving the reliability of the MEMS microphone, reducing costs, and thus being used for mass production.

[0102] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, it should be understood by those skilled in the art that various technical means can be used to form layers, regions, etc. of the desired shape. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0103] The embodiments of the present invention are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A micro-electromechanical structure, characterized in that: include: Back panel; A vibration membrane having at least one through hole and forming a variable capacitor with the back plate; At least one connecting post, one end of each connecting post being fixedly connected to the back plate; as well as At least one movable structure is respectively located in the corresponding through hole to be separated from the vibration membrane, and each movable structure is fixedly connected to the other end of the corresponding connecting column, The gap between the movable structure and the through hole is used for gas circulation. At least one of the movable knots comprises a groove and / or a venting groove, The groove and the air release groove penetrate the movable structure. The groove extends inward from the edge of the movable structure and communicates with the gap.

2. The micro-electromechanical structure according to claim 1, characterized in that: The at least one movable structure includes the movable structure in the form of a cylinder and / or the movable structure in the form of a polygonal column. Wherein, the shape of the movable structure matches the through hole.

3. The micro-electromechanical structure according to claim 1, characterized in that: The at least one movable structure includes the movable structure in the form of a cylinder and / or the movable structure in the form of a polygonal column. The at least one groove extends radially inward from the cylindrical surface of the movable structure.

4. The micro-electromechanical structure according to claim 3, characterized in that: There are multiple grooves, and the openings of the multiple grooves are evenly distributed along the outer peripheral edge of the movable structure.

5. The micro-electromechanical structure according to claim 3, characterized in that: There are multiple air release grooves, which surround the center of the movable structure and are separated from each other.

6. The micro-electromechanical structure according to claim 3, characterized in that: The movable structure includes a plurality of the air release grooves and a plurality of the grooves, and the number of the air release grooves is the same as the number of the grooves. The openings of the plurality of grooves are evenly distributed along the outer peripheral edge of the movable structure, the plurality of air relief grooves surround the center of the movable structure, and each of the air relief grooves is located between two adjacent grooves and is separated from the grooves.

7. The micro-electromechanical structure according to any one of claims 1 to 6, characterized in that: The center of each movable structure is connected to the corresponding connecting column.

8. The micro-electromechanical structure according to claim 7, characterized in that: The back plate has a plurality of air leakage holes, and the orthographic projection of at least one air leakage hole falls within the orthographic projection of the movable structure.

9. The micro-electromechanical structure according to claim 8, characterized in that: The back plate comprises: an insulating layer connected to the connecting pillar; and a conductive layer, located on the insulating layer, Wherein, at least one of the air leakage holes penetrates the insulating layer and the conductive layer.

10. The micro-electromechanical structure according to any one of claims 1 to 6, characterized in that: The back plate comprises: A fixing part, fixedly connected to the vibration membrane via a supporting structure; At least one connecting portion, separated from the fixing portion and fixedly connected to the corresponding connecting column; and a beam structure connecting the fixing portion and the connecting portion, Wherein, an air flow channel is provided between the fixing portion, the connecting portion and the beam structure.

11. The micro-electromechanical structure according to claim 10, characterized in that: The beam structure includes a bent beam and / or a cantilever beam.

12. The micro-electromechanical structure according to claim 11, characterized in that: The connecting portion corresponds to the center of the movable structure, Wherein, two ends of the connecting column are respectively connected to the center of the connecting portion and the center of the movable structure.

13. The micro-electromechanical structure according to claim 12, characterized in that: The orthographic projection of the connecting portion falls within the orthographic projection of the movable structure; or the orthographic projection of the movable structure falls within the orthographic projection of the connecting portion; Alternatively, the orthographic projection of the movable structure coincides with the orthographic projection of the connecting portion.

14. The micro-electromechanical structure according to claim 10, characterized in that: The connecting portion has at least one air leakage hole, and the at least one air leakage hole surrounds the center of the connecting portion.

15. A MEMS microphone, characterized in that: The micro-electromechanical structure comprises the micro-electromechanical structure as claimed in any one of claims 1 to 14.

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