A MEMS device and a method of manufacturing the same

Abstract

The application provides a MEMS device and a manufacturing method thereof. The method comprises the following steps: providing a first substrate and a second substrate, one of which is provided with a first bonding structure on a first surface, and the other of which is provided with a second bonding structure on a first surface; bonding the first bonding structure and the second bonding structure to obtain a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, a second diaphragm, a fourth sacrificial layer, a second backplate layer and a fifth sacrificial layer, a first cavity is formed between the first diaphragm and the second diaphragm, a plurality of first release holes are formed in the first backplate layer, a plurality of connecting columns are formed in the first cavity, the connecting columns are arranged in the first release holes and are connected with the first diaphragm and the second diaphragm respectively; removing the second substrate, removing a part of the first substrate corresponding to the first cavity to form a back cavity, and removing part of the sacrificial layer. The application scheme can simplify the process, reduce the cost, improve the signal-to-noise ratio, sensitivity, efficiency and yield.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a MEMS device and a method for manufacturing the same. Background Technology

[0002] With the continuous development of semiconductor technology, MEMS microphones, which are fabricated based on micro-electro-mechanical systems (MEMS) technology, are widely used in the sensor product market due to their advantages such as small size, low cost and stable performance compared with traditional microphones.

[0003] A typical condenser MEMS microphone consists of a single-layer diaphragm and a single-layer backplate. The single-layer diaphragm and the single-layer backplate constitute a capacitor structure. When an external sound signal acts on the diaphragm, the diaphragm vibrates, causing a change in capacitance. The change in capacitance is used for calculation and operation to complete the conversion between sound signals and electrical signals.

[0004] With the development of technology, the performance of single-diaphragm / single-backplane MEMS microphones can no longer meet the needs, and dual-diaphragm / dual-backplane MEMS microphones have emerged. Dual-diaphragm / dual-backplane MEMS microphones can further improve key performance, such as low noise and high sensitivity.

[0005] However, MEMS microphones with dual diaphragms / dual backplates in related technologies suffer from problems such as poor uniformity, easy warping, complicated processes, high costs, and low yield. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] To address the existing problems, this application provides a method for manufacturing a MEMS device, comprising:

[0008] A first substrate and a second substrate are provided, wherein a first bonding structure is formed on a first surface of one of the first substrate and a second bonding structure is formed on the first surface of the other substrate;

[0009] The first bonding structure and the second bonding structure are bonded together to obtain a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, a second diaphragm, a fourth sacrificial layer, a second backplate layer, and a fifth sacrificial layer stacked from the first bonding structure to the second bonding structure. A first cavity is formed between the first diaphragm and the second diaphragm. A plurality of first release holes are formed in the first backplate layer and a plurality of connecting posts are formed in the first cavity. The connecting posts pass through the first release holes and connect the first diaphragm and the second diaphragm respectively.

[0010] Remove the second substrate, remove the portion of the first substrate corresponding to the first cavity from the second surface of the first substrate to form a back cavity, and remove a portion of the sacrificial layer: when the first bonding structure is formed on the first surface of the first substrate, remove the fifth sacrificial layer and the first sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity; when the first bonding structure is formed on the first surface of the second substrate, remove the first sacrificial layer and the fifth sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity.

[0011] Exemplarily, the first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, and a third sacrificial layer stacked together. A first cavity is formed on the first diaphragm, and the connecting post is formed in the first cavity. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second diaphragm stacked together. In the bonding step, the third sacrificial layer and the connecting post are bonded to the second diaphragm; or

[0012] The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, and a first sub-diaphragm, all stacked together. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second sub-diaphragm, all stacked together. In the bonding step, the first sub-diaphragm and the second sub-diaphragm are bonded together, and the first sub-diaphragm and the second sub-diaphragm constitute the second diaphragm; or

[0013] The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, and a second diaphragm stacked together; the second bonding structure includes a fifth sacrificial layer, a second backplate layer, and a fourth sacrificial layer stacked together; and in the bonding step, the second diaphragm is bonded to the fourth sacrificial layer; or

[0014] The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, and a first sub-sacrificial layer stacked together. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, and a second sub-sacrificial layer stacked together. In the bonding step, the first sub-sacrificial layer and the second sub-sacrificial layer are bonded together, and the first sub-sacrificial layer and the second sub-sacrificial layer constitute the fourth sacrificial layer; or

[0015] The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, and a fourth sacrificial layer stacked together; the second bonding structure includes a fifth sacrificial layer and a second backplate layer stacked together; and in the bonding step, the fourth sacrificial layer is bonded to the second backplate layer; or

[0016] The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, a fourth sacrificial layer, and a first sub-backplate layer stacked together. The second bonding structure includes a fifth sacrificial layer and a second sub-backplate layer stacked together. In the bonding step, the first sub-backplate layer and the second sub-backplate layer are bonded together, and the first sub-backplate layer and the second sub-backplate layer constitute the second backplate layer.

[0017] For example, when the first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, and a third sacrificial layer stacked together, a first cavity is formed on the first diaphragm, and the connecting post is formed in the first cavity, and the second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second diaphragm stacked together, a connecting layer is also formed on the surface of the connecting post for bonding with the second diaphragm, and the width of the connecting layer is greater than the width of the connecting post.

[0018] For example, the first backsheet layer includes a first dielectric layer, a first conductive layer and a second dielectric layer stacked from the second sacrificial layer toward the third sacrificial layer;

[0019] The second backsheet layer includes a third dielectric layer, a second conductive layer, and a fourth dielectric layer stacked from the fourth sacrificial layer toward the fifth sacrificial layer;

[0020] The bonding step involves bonding the first sub-backplane layer to the second sub-backplane layer, including:

[0021] The first sub-backplane layer includes a first sub-dielectric layer, and the second sub-backplane layer includes a second sub-dielectric layer, a second conductive layer, and the fourth dielectric layer. In the bonding step, the first sub-dielectric layer and the second sub-dielectric layer are bonded together, and the first sub-dielectric layer and the second sub-dielectric layer constitute the third dielectric layer; or

[0022] The first sub-backplane layer includes the third dielectric layer, and the second sub-backplane layer includes the second conductive layer and the fourth dielectric layer. In the bonding step, the third dielectric layer and the second conductive layer are bonded; or

[0023] The first sub-backplane layer includes the third dielectric layer and the first sub-conductive layer, and the second sub-backplane layer includes the second sub-conductive layer and the fourth dielectric layer. In the bonding step, the first sub-conductive layer and the second sub-conductive layer are bonded together, and the first sub-conductive layer and the second sub-conductive layer constitute the second conductive layer; or

[0024] The first sub-backplane layer includes the third dielectric layer and the second conductive layer, and the second sub-backplane layer includes the fourth dielectric layer. In the bonding step, the second conductive layer is bonded to the fourth dielectric layer; or

[0025] The first sub-backplane layer includes the third dielectric layer, the second conductive layer, and the third sub-dielectric layer. The second sub-backplane layer includes the fourth sub-dielectric layer. In the bonding step, the third sub-dielectric layer and the fourth sub-dielectric layer are bonded together, and the third sub-dielectric layer and the fourth sub-dielectric layer constitute the fourth dielectric layer.

[0026] For example, in the bonding step, the material combination of the bonding surfaces of the first bonding structure and the second bonding structure is at least one of the following: amorphous silicon-amorphous silicon, silicon nitride-oxide, silicon nitride-amorphous silicon, silicon nitride-polycrystalline silicon, silicon nitride-silicon nitride, polycrystalline silicon-polycrystalline silicon, amorphous silicon-polycrystalline silicon, oxide-amorphous silicon, oxide-polycrystalline silicon, and oxide-oxide.

[0027] For example, the first diaphragm and the second diaphragm are electrically connected through a first conductive contact, and the first conductive layer and the second conductive layer are electrically connected through a second conductive contact.

[0028] For example, prior to performing the bonding step, the method further includes:

[0029] An anti-sputtering layer is formed on the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure; or

[0030] Activate the bonding surfaces of the first bonding structure and / or the bonding surfaces of the second bonding structure.

[0031] For example, after performing the bonding step, the method further includes etching the first diaphragm, the connecting post, and the second diaphragm to form an exhaust hole that penetrates the first diaphragm, the connecting post, and the second diaphragm, wherein the exhaust hole is not in communication with the first cavity.

[0032] For example, the first diaphragm has a textured structure formed on the portion corresponding to the cavity, and / or the second diaphragm has a textured structure formed on the portion corresponding to the cavity.

[0033] This application also provides a MEMS device, which is manufactured using the aforementioned method.

[0034] The MEMS devices and manufacturing methods of the embodiments of this application form MEMS devices with dual diaphragm / dual backplane layers through bonding processes. While improving performance, sensitivity and signal-to-noise ratio, they can simplify manufacturing processes, reduce costs, improve efficiency and yield, improve uniformity, avoid warping and other problems, and also adjust the vacuum level. Attached Figure Description

[0035] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions to explain the principles of the invention.

[0036] In the attached image:

[0037] Figure 1 A flowchart illustrating a method for manufacturing a MEMS device according to an exemplary embodiment of this application is shown;

[0038] Figure 2 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0039] Figure 3 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0040] Figure 4 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0041] Figure 5 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0042] Figure 6This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0043] Figure 7 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0044] Figure 8 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0045] Figure 9 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0046] Figure 10 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0047] Figure 11 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0048] Figure 12 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0049] Figure 13 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0050] Figure 14 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0051] Figure 15 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0052] Figure 16 This illustration shows a cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application.

[0053] Figure 17A schematic cross-sectional view of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application is shown.

[0054] Figure 18 A cross-sectional schematic diagram of a MEMS device obtained by sequentially implementing a method for manufacturing a MEMS device according to an exemplary embodiment of this application is shown. Detailed Implementation

[0055] The present application will now be described more fully with reference to the accompanying drawings, in which embodiments of the present application are illustrated. However, the present application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0056] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0057] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0058] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0059] Embodiments of the application are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures). Thus, variations from the shapes shown can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the application should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing processes. For example, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of the regions of the device and are not intended to limit the scope of the application.

[0060] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms as defined in commonly used dictionaries shall be interpreted as having a meaning consistent with their meaning in the relevant field and / or the context of this specification, and not as in an ideal or overly formal sense, unless expressly defined herein.

[0061] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solutions proposed in this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0062] MEMS microphones with dual diaphragms / dual backplanes in related technologies are generally manufactured using traditional thin-film growth processes that involve layer stacking. This manufacturing process is difficult and complicated, and requires sophisticated equipment, resulting in long processing times and high costs. In addition, problems such as excessive warping and poor uniformity can easily occur during the layer stacking growth process, leading to a decrease in yield.

[0063] In view of the aforementioned technical problems, this application proposes a method for manufacturing a MEMS device, comprising:

[0064] Step S1: Provide a first substrate and a second substrate, wherein a first bonding structure is formed on the first surface of one of the first substrate and a second bonding structure is formed on the first surface of the other substrate;

[0065] Step S2: The first bonding structure and the second bonding structure are bonded together to obtain a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, a second diaphragm, a fourth sacrificial layer, a second backplate layer, and a fifth sacrificial layer stacked from the first bonding structure to the second bonding structure. A first cavity is formed between the first diaphragm and the second diaphragm. A plurality of first release holes are formed in the first backplate layer and a plurality of connecting posts are formed in the first cavity. The connecting posts pass through the first release holes and connect the first diaphragm and the second diaphragm respectively.

[0066] Step S3: Remove the second substrate. Remove the portion of the first substrate corresponding to the first cavity from the second surface of the first substrate to form a back cavity, and remove a portion of the sacrificial layer: When a first bonding structure is formed on the first surface of the first substrate, remove the fifth sacrificial layer and the first sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity; When a first bonding structure is formed on the first surface of the second substrate, remove the first sacrificial layer and the fifth sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity.

[0067] The MEMS device manufacturing method of this application forms a MEMS device with dual diaphragm / dual backplane layers through a bonding process. While improving performance, sensitivity and signal-to-noise ratio, it can simplify the manufacturing process, reduce costs, improve efficiency and yield, improve uniformity, avoid warping and other problems, and also adjust the vacuum level.

[0068] Example 1

[0069] Below, for reference Figures 1 to 18 The manufacturing method of the MEMS device of this application is described in detail. Exemplarily, the manufacturing method of the MEMS device of this application includes the following steps:

[0070] First, step S1 is performed, providing a first substrate and a second substrate, wherein a first bonding structure is formed on the first surface of one of the first substrates and a second bonding structure is formed on the first surface of the other.

[0071] The MEMS device can be any suitable device known to those skilled in the art, such as a MEMS microphone or a MEMS pressure sensor. In this embodiment, the technical solution of the present invention is explained and illustrated mainly by taking the case of the MEMS device being a MEMS microphone.

[0072] In one example, such as Figures 2 to 12 As shown, the first substrate 210 and the second substrate 220 are bulk silicon substrates, which may include at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors. Alternatively, the first substrate 210 and the second substrate 220 may also include silicon-on-insulator (SOI), silicon-on-insulator stacked (SSOI), silicon-on-insulator stacked germanium (S-SiGeOI), silicon-on-insulator (SiGeOI), or germanium-on-insulator (GeOI), etc. Although several examples of materials that can form the first substrate 210 and the second substrate 220 have been described herein, any material that can serve as a semiconductor substrate falls within the spirit and scope of this application.

[0073] In one example, a first bonding structure is formed on the first surface of one of the first substrate 210 and the second substrate 220, and a second bonding structure is formed on the first surface of the other. The following description uses the example of the first bonding structure being formed on the first surface of the first substrate 210 and the second bonding structure being formed on the first surface of the second substrate 220.

[0074] Next, proceed to step S2, as follows: Figures 2 to 12 As shown, the first bonding structure and the second bonding structure are bonded together to obtain a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, a second diaphragm 216, a fourth sacrificial layer 217, a second backplate layer 218, and a fifth sacrificial layer 219 stacked from the first bonding structure to the second bonding structure. A first cavity 250 is formed between the first diaphragm 212 and the second diaphragm 216. A plurality of first release holes 240 located in the first cavity 250 are formed in the first backplate layer 214. A plurality of connecting posts 230 are formed in the first cavity 250. The connecting posts 230 pass through the first release holes 240 and connect the first diaphragm 212 and the second diaphragm 216 respectively.

[0075] In one example, such as Figure 2As shown, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, and a third sacrificial layer 215 stacked together. A first cavity 250 is formed on the first diaphragm 212, and a connecting post 230 is formed in the first cavity 250. The first sacrificial layer 211 is located on the first surface of the first substrate 210. The second bonding structure includes a fifth sacrificial layer 219, a second backplate layer 218, a fourth sacrificial layer 217, and a second diaphragm 216 stacked together. The fifth sacrificial layer 219 is located on the first surface of the second substrate 220. In the bonding step, the third sacrificial layer 215 and the connecting post 230 are bonded to the second diaphragm 216. Exemplarily, the top surface of the connecting post 230 is flush with the top surface of the third sacrificial layer 215.

[0076] In one example, it can be formed through the following steps: Figure 2 The first substrate 210 and the first bonding structure shown are as follows: a first substrate 210 is provided; a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213 and a first backplate layer 214 are sequentially formed on a first surface of the first substrate 210; the first backplate layer 214 is etched to form a plurality of first release holes 240 penetrating the first backplate layer 214; a dielectric layer filling the first release holes 240 and a third sacrificial layer 215 located on the first backplate layer 214 are formed; a portion of the third sacrificial layer 215, a portion of the dielectric layer and a portion of the second sacrificial layer 213 are etched away to form a plurality of connection holes exposing the first diaphragm 212, the plurality of connection holes being disposed in the first release holes 240; a connecting post 230 filling the connection holes is formed; a portion of the third sacrificial layer 215, the dielectric layer and a portion of the second sacrificial layer 213 are removed to form a cavity 250.

[0077] In one example, it can be formed through the following steps: Figure 2 The second substrate 220 and the second bonding structure shown: a second substrate 220 is provided; a fifth sacrificial layer 219, a second backplate layer 218, a fourth sacrificial layer 217 and a second diaphragm 216 are sequentially formed on the first surface of the second substrate 220.

[0078] In one example, various deposition processes commonly used in the art can be employed to form the aforementioned film layer, such as epitaxial growth, chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD), etc., and this application does not impose any limitations on this. Exemplarily, various etching processes commonly used in the art can be employed to perform the aforementioned etching steps, such as dry etching processes or wet etching processes, etc. For example, a buffer oxide etchant can be used, or gaseous hydrogen fluoride (VHF) can be used to remove part of the third sacrificial layer 215, the dielectric layer, and part of the second sacrificial layer 213 to form the cavity 250.

[0079] In one example, the materials of the first sacrificial layer 211, the second sacrificial layer 213, the third sacrificial layer 215, the fourth sacrificial layer 217 and the fifth sacrificial layer 219 may include, but are not limited to, one or more of silicon nitride and silicon oxide, or may be any other suitable insulating material, such as TiO2, TaO2, etc., which are not limited in this application.

[0080] In one example, the materials of the first diaphragm 212 and the second diaphragm 216 include, but are not limited to, materials such as polycrystalline silicon, amorphous silicon, metal, SOI porous materials, etc., and can also be any other suitable conductive material, which is not limited in this application. Exemplarily, the first diaphragm 212 and the second diaphragm 216 can also be composite materials, such as silicon nitride / polycrystalline silicon, oxide / polycrystalline silicon, polycrystalline silicon / amorphous silicon, or amorphous silicon / polycrystalline silicon / amorphous silicon composite materials.

[0081] In one example, such as Figures 2 to 12 As shown, the first backplane layer 214 includes a first dielectric layer 2141, a first conductive layer 2142, and a second dielectric layer 2143 stacked from the second sacrificial layer 213 to the third sacrificial layer 215; the second backplane layer 218 includes a third dielectric layer 2181, a second conductive layer 2182, and a fourth dielectric layer 2183 stacked from the fourth sacrificial layer 217 to the fifth sacrificial layer 219. Exemplarily, the materials of the first dielectric layer 2141, the second dielectric layer 2143, the third dielectric layer 2181, and the fourth dielectric layer 2183 include, but are not limited to, materials such as SiCN, SiN, SiC, and SiON. Exemplarily, the materials of the first conductive layer 2142 and the second conductive layer 2182 include, but are not limited to, materials such as polycrystalline silicon, amorphous silicon, and metal, and can also be any other suitable conductive material; this application does not impose any limitations on this. For example, the first backplane layer 214 may include only the first dielectric layer 2141 and the first conductive layer, or only the first conductive layer 2142 and the second dielectric layer 2143; the second backplane layer 218 may include only the third dielectric layer 2181 and the second conductive layer 2182, or only the second conductive layer 2182 and the fourth dielectric layer 2183.

[0082] In one example, the material of the connecting post 230 includes SiN, SiO2 wrapped by SiN, polycrystalline silicon wrapped by SiN, or amorphous silicon wrapped by SiN, or the material of the connecting post 230 may be other suitable materials, which are not limited in this application.

[0083] In one example, the connecting post 230 is in the form of a ring, a square, a king-shaped shape, or a honeycomb prism, or the connecting post 230 may be any other suitable shape.

[0084] In one example, the cross-section of the connecting post 230 is circular, rectangular, hexagonal, or octagonal, or the cross-section of the connecting post 230 may be any other suitable shape.

[0085] In one example, such as Figure 3 As shown, when the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, and a third sacrificial layer 215 stacked together, a first cavity 250 is formed on the first diaphragm 212, and a connecting post 230 is formed in the first cavity 250, and the second bonding structure includes a fifth sacrificial layer 219, a second backplate layer 218, a fourth sacrificial layer 217, and a second diaphragm 216 stacked together, a connecting layer 231 is also formed on the surface of the connecting post 230 used for bonding with the second diaphragm 216, and the width of the connecting layer 231 is greater than the width of the connecting post 230. Exemplarily, by forming a connecting layer 231 with a width greater than the width of the connecting post 230, the bonding area can be increased, and the bonding effect enhanced. Exemplarily, the connecting layer 231 has the same material as the connecting post 230. For example, the material of the connecting layer 231 may include SiN, SiO2 encapsulated by SiN, polycrystalline silicon encapsulated by SiN, or amorphous silicon encapsulated by SiN, or the material of the connecting layer 231 may be any suitable material. Exemplarily, the top surface of the connecting layer 231 is flush with the top surface of the third sacrificial layer 215. Exemplarily, the width of the connecting post 230 is generally small, and when the connecting post 230 is bonded to the second diaphragm 216, the bonding surface is a point-to-face bonding structure; however, by forming a connecting layer 231 with a larger width, when the connecting layer 231 is bonded to the second diaphragm 216, the bonding surface becomes a face-to-face bonding structure.

[0086] In one example, such as Figure 4 As shown, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, and a first sub-diaphragm 2161 stacked together. The second bonding structure includes a fifth sacrificial layer 219, a second backplate layer 218, a fourth sacrificial layer 217, and a second sub-diaphragm 2162 stacked together. In the bonding step, the first sub-diaphragm 2161 and the second sub-diaphragm 2162 are bonded together, and the first sub-diaphragm 2161 and the second sub-diaphragm 2162 constitute the second diaphragm 216.

[0087] In one example, a bonding process can be used to form such as Figure 4The first substrate 210 and the first bonding structure located on the first surface of the first substrate 210 are shown: a first substrate is provided, and a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213 and a first dielectric layer 2141 are formed on the first surface of the first substrate 210. The dielectric layer at the location where the first release hole 240 is to be formed and the second sacrificial layer 213 at the location where the first cavity 250 is to be formed are removed by an etching process, and a partial connecting post 230 is formed, the top surface of which is flush with the top surface of the first dielectric layer 2141; a first sub-sub- A diaphragm 2161 has a third sacrificial layer 215, a second dielectric layer 2143, and a first conductive layer 2142 sequentially formed on its surface. The dielectric layer at the predetermined location for forming the first release hole 240 and the third sacrificial layer 215 at the predetermined location for forming the first cavity 250 are removed by an etching process, and partial connecting posts 230 are formed, with the top surface of the partial connecting posts 230 flush with the top surface of the first conductive layer 2142. A bonding process is then performed, wherein the first dielectric layer 2141 and the first conductive layer 2142 are bonded together, and the connecting posts 230 are bonded together. In this step, other bonding interfaces can also be selected for bonding to obtain, for example... Figure 4 The structure shown can also allow the first conductive layer 2142 and the second dielectric layer 2143 to be bonded together, and the connecting posts 230 to be bonded together. During this bonding step, the vacuum level of the formed first cavity 250 can be adjusted by regulating the vacuum level during bonding.

[0088] In one example, such as Figure 5 As shown, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, and a second diaphragm 216 stacked together. The second bonding structure includes a fifth sacrificial layer 219, a second backplate layer 218, and a fourth sacrificial layer 217 stacked together. In the bonding step, the second diaphragm 216 and the fourth sacrificial layer 217 are bonded together.

[0089] In one example, such as Figure 6 As shown, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, a second diaphragm 216, and a first sub-sacrificial layer 2171 stacked together. The second bonding structure includes a fifth sacrificial layer 219, a second backplate layer 218, and a second sub-sacrificial layer 2172 stacked together. In the bonding step, the first sub-sacrificial layer 2171 and the second sub-sacrificial layer 2172 are bonded together, and the first sub-sacrificial layer 2171 and the second sub-sacrificial layer 2172 constitute the fourth sacrificial layer 217.

[0090] In one example, such as Figure 7As shown, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, a second diaphragm 216, and a fourth sacrificial layer 217 stacked together. The second bonding structure includes a fifth sacrificial layer 219 and a second backplate layer 218 stacked together. In the bonding step, the fourth sacrificial layer 217 and the second backplate layer 218 are bonded together.

[0091] In one example, the first bonding structure includes a first sacrificial layer 211, a first diaphragm 212, a second sacrificial layer 213, a first backplate layer 214, a third sacrificial layer 215, a second diaphragm 216, a fourth sacrificial layer 217, and a first sub-backplate layer stacked together. The second bonding structure includes a fifth sacrificial layer 219 and a second sub-backplate layer stacked together. In the bonding step, the first sub-backplate layer and the second sub-backplate layer are bonded together, and the first sub-backplate layer and the second sub-backplate layer constitute the second backplate layer 218.

[0092] In one example, such as Figure 8 As shown, the first sub-backplane layer includes a first sub-dielectric layer 21811, and the second sub-backplane layer includes a second sub-dielectric layer 21812, a second conductive layer 2182, and a fourth dielectric layer 2183. In the bonding step, the first sub-dielectric layer 21811 and the second sub-dielectric layer 21812 are bonded together, and the first sub-dielectric layer 21811 and the second sub-dielectric layer 21812 constitute the third dielectric layer 2181.

[0093] In one example, such as Figure 9 As shown, the first sub-backplane layer includes a third dielectric layer 2181, and the second sub-backplane layer includes a second conductive layer 2182 and a fourth dielectric layer 2183. In the bonding step, the third dielectric layer 2181 and the second conductive layer 2182 are bonded together.

[0094] In one example, such as Figure 10 As shown, the first sub-backsheet layer includes a third dielectric layer 2181 and a first sub-conductive layer 21821, and the second sub-backsheet layer includes a second sub-conductive layer 21822 and a fourth dielectric layer 2183. In the bonding step, the first sub-conductive layer 21821 and the second sub-conductive layer 21822 are bonded together, and the first sub-conductive layer 21821 and the second sub-conductive layer 21822 constitute the second conductive layer 2182.

[0095] In one example, such as Figure 11 As shown, the first sub-backplane layer includes a third dielectric layer 2181 and a second conductive layer 2182, and the second sub-backplane layer includes a fourth dielectric layer 2183. In the bonding step, the second conductive layer 2182 and the fourth dielectric layer 2183 are bonded together.

[0096] In one example, such as Figure 12As shown, the first sub-backplane layer includes a third dielectric layer 2181, a second conductive layer 2182, and a third sub-dielectric layer 21831. The second sub-backplane layer includes a fourth sub-dielectric layer 21832. In the bonding step, the third sub-dielectric layer 21831 and the fourth sub-dielectric layer 21832 are bonded together, and the third sub-dielectric layer 21831 and the fourth sub-dielectric layer 21832 constitute the fourth dielectric layer 2183.

[0097] In one example, when a first bonding structure is formed on the first surface of the second substrate 220 and a second bonding structure is formed on the first surface of the first substrate 210, the bonding method of the first bonding structure and the second bonding structure can refer to the various bonding methods described above, and will not be repeated here.

[0098] In one example, various bonding processes conventional in the art can be used to perform the above bonding steps, such as low-temperature bonding (followed by low-temperature annealing at a temperature below 450°C), high-temperature bonding (followed by high-temperature annealing at a temperature above 450°C), vacuum direct bonding, and hybrid bonding (e.g., in an embodiment where the first sub-sacrificial layer 2171 and the second sub-sacrificial layer 2172 are bonded, a conductive material with a slightly lower top surface, such as copper, can be formed in the first sub-sacrificial layer 2171 and the second sub-sacrificial layer 2172 first). This application does not impose any limitations on these comparisons. Exemplarily, compared to high-temperature annealing after bonding, low-temperature annealing or even no annealing after bonding can effectively avoid device damage or device failure caused by lattice mismatch.

[0099] In one example, prior to the bonding step, the method further includes: forming an anti-sputtering layer (not shown) on the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure; or activating the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure. Exemplarily, forming the anti-sputtering layer can improve the bond and interface, and enhance the bonding strength. Exemplarily, the material of the anti-sputtering layer includes, but is not limited to, alumina, silicon oxide, amorphous silicon, titanium, chromium, etc. Exemplarily, activating the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure (e.g., activating the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure using plasma) can enhance the bonding strength.

[0100] In one example, as described above, the bonding process in this application can select different bonding positions, bonding surface materials, and bonding processes according to actual needs, offering strong selectivity and adaptability to various processes and application scenarios. Specifically, in the bonding step, the material combination of the bonding surfaces of the first and second bonding structures can be at least one of the following: amorphous silicon-amorphous silicon, silicon nitride-oxide, silicon nitride-amorphous silicon, silicon nitride-polycrystalline silicon, silicon nitride-silicon nitride, polycrystalline silicon-polycrystalline silicon, amorphous silicon-polycrystalline silicon, oxide-amorphous silicon, oxide-polycrystalline silicon, and oxide-oxide.

[0101] Specifically, taking the second diaphragm 216 as a composite material of polycrystalline silicon / amorphous silicon as an example, in the bonding step, the first sub-diaphragm 2161 and the second sub-diaphragm 2162 are bonded. At this time, the material combination of the bonding surface can be amorphous silicon-amorphous silicon, polycrystalline silicon-polycrystalline silicon, or amorphous silicon-polycrystalline silicon. Meanwhile, the area outside the second diaphragm 216 is the bonding between sacrificial layers. The material combination of the bonding surface between the sacrificial layers is oxide-oxide. That is, at this time, the material combination of the bonding surface can be oxide-oxide and amorphous silicon-amorphous silicon at the same time, or oxide-oxide and polycrystalline silicon-polycrystalline silicon at the same time, or oxide-oxide and amorphous silicon-polycrystalline silicon at the same time.

[0102] Taking the connecting post 230 as silicon nitride, the second diaphragm 216 as polycrystalline silicon, amorphous silicon, or a composite material of polycrystalline silicon / amorphous silicon, and the third sacrificial layer as oxide as an example, in the bonding step, the third sacrificial layer 215 and the connecting post 230 are bonded to the second diaphragm 216. At this time, the material combination of the bonding surface is simultaneously silicon nitride-amorphous silicon and oxide-amorphous silicon, or simultaneously silicon nitride-polycrystalline silicon and oxide-polycrystalline silicon. Meanwhile, the area outside the second diaphragm 216 is the bonding between the sacrificial layers. At this time, it is the bonding between the bonding surfaces of two composite materials. The material combination of the bonding surface is simultaneously silicon nitride-amorphous silicon, oxide-amorphous silicon, and oxide-oxide, or simultaneously silicon nitride-polycrystalline silicon, oxide-polycrystalline silicon, and oxide-oxide.

[0103] Taking the third dielectric layer 2181 as silicon nitride and the fourth sacrificial layer 217 as oxide as an example, the third dielectric layer 2181 and the fourth sacrificial layer are bonded in the bonding step, and the material combination of the bonding surface is silicon nitride-oxide.

[0104] Taking silicon nitride as an example, the first sub-dielectric layer 21811 and the second sub-dielectric layer 21812 are bonded in the bonding step. At this time, the material combination of the bonding surface is silicon nitride-silicon nitride.

[0105] In one example, the material combination of at least one bonding surface can also be achieved by forming a backsplash layer or by an activation process. For example, by forming an oxide backsplash layer on both the bonding surfaces of the first and second bonding structures, an oxide-oxide bonding surface material combination can be achieved, which will not be elaborated further here. Exemplarily, in the bonding step, bonding can be performed between two bonding surfaces of a single material, or between a bonding surface of a single material and a bonding surface of a composite material, or between two bonding surfaces of a composite material.

[0106] In one example, this application uses a bonding process to fabricate a MEMS device with dual diaphragms / dual backplanes. This effectively solves the film warping problem caused by the release of multiple sacrificial layers and stress in traditional layer-by-layer thin film growth processes, and also solves the problem of insufficient film thickness due to stress. This simplifies the process, reduces costs, and improves efficiency and yield. Furthermore, the vacuum level of the device can be adjusted by regulating the vacuum level during the bonding step; for example, the vacuum level of the first cavity 250 can be adjusted from 10^-6 Pa to 0 Pa.

[0107] Finally, step S3 is executed to remove the second substrate, remove the portion of the first substrate corresponding to the first cavity from the second surface of the first substrate to form a back cavity, and remove a portion of the sacrificial layer: when a first bonding structure is formed on the first surface of the first substrate, remove the fifth sacrificial layer and the first sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity; when a first bonding structure is formed on the first surface of the second substrate, remove the first sacrificial layer and the fifth sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity.

[0108] In one example, the second substrate 220 and the portion of the first substrate 210 corresponding to the first cavity 250 can be removed by an etching process conventional in the art to form the back cavity 280.

[0109] In one example, such as Figure 13 As shown, when a first bonding structure is formed on the first surface of the first substrate 210, removing a portion of the sacrificial layer includes: removing the fifth sacrificial layer 219 and the first sacrificial layer 211 exposed in the back cavity, and removing a portion of the fourth sacrificial layer 217 to form a second cavity 270 corresponding to the first cavity 250. Exemplarily, a plurality of second release holes 260 are formed in the second backplate layer 218, and a portion of the fourth sacrificial layer 217 is removed through the second release holes 260 to form the second cavity 270 corresponding to the first cavity 250.

[0110] In one example, such as Figure 14As shown, when a first bonding structure is formed on the first surface of the second substrate 220, the removal of a portion of the sacrificial layer includes: removing the first sacrificial layer 211 and the fifth sacrificial layer 219 exposed in the back cavity, and removing a portion of the fourth sacrificial layer 217 to form a second cavity 270 corresponding to the first cavity 250.

[0111] In one example, the second cavity 270 can be formed first, and then bonding can be performed; or the back cavity 280 can be formed first, and then bonding can be performed.

[0112] In one example, the step also includes forming pads (not shown) to lead out each diaphragm and each backplate layer; or, as... Figure 15 and Figure 16 As shown, it also includes the step of forming a wiring layer 290 that leads out each diaphragm and each backplane layer. Exemplarily, as... Figure 15 and Figure 16 As shown, the sidewalls of the wiring layer 290 are all covered with an insulating material. Exemplarily, the wiring layer 290 can be formed by a through-silicon via (TSV) process or an etching process.

[0113] In one example, after performing the bonding step, the process further includes etching the first diaphragm 212, the connecting post 230, and the second diaphragm 216 to form an vent (not shown) penetrating the first diaphragm 212, the connecting post 230, and the second diaphragm 216. The vent is not connected to the first cavity 250. Exemplarily, the vent is connected to both the back cavity 280 and the second cavity 270, which can be used to balance air pressure, thereby improving the performance and reliability of the MEMS device. Exemplarily, the portions of the first diaphragm 212 and the second diaphragm 216 corresponding to the connecting post 230 and the connecting post 230 are etched to form the vent. Exemplarily, the size of the vent is smaller than the size of the connecting post 230, and the connecting post 230 with the vent is a hollow cylinder. Exemplarily, the connecting post 230 located at the center of the first cavity 250 and the portions of the first diaphragm 212 and the second diaphragm corresponding to the connecting post 230 can be etched to form the vent; the vent being located at the center can make the force more uniform. Exemplarily, one or more vents can be formed; this application is not limited in this respect. Exemplarily, when the interconnect layer 231 is formed, the vent hole also extends through the interconnect layer 231. Exemplarily, the vent hole can be formed by etching after removing the second substrate 220 and before removing a portion of the sacrificial layer; alternatively, the vent hole can be formed by etching after forming the back cavity 280 and before removing a portion of the sacrificial layer; alternatively, the vent hole can be formed by etching after removing a portion of the sacrificial layer. Exemplarily, the vent hole can be formed by photolithography and TSV processes.

[0114] In one example, the portion of the first diaphragm 212 corresponding to the cavity has a textured film structure, and / or, the portion of the second diaphragm 216 corresponding to the cavity has a textured film structure. Exemplarily, since the first cavity 250 and the second cavity 270 are correspondingly arranged, the portion of the first diaphragm 212 corresponding to the first cavity 250 is the same as the portion corresponding to the second cavity 270, and the portion of the second diaphragm 216 corresponding to the first cavity 250 is the same as the portion corresponding to the second cavity 270. Therefore, the portion corresponding to the cavity can refer to either the portion corresponding to the first cavity 250 or the portion corresponding to the second cavity 270. Figure 17 As shown, Figure 17 The illustration shows that both the portion of the first diaphragm 212 corresponding to the cavity and the portion of the second diaphragm 216 corresponding to the cavity have textured film structures. In other embodiments, only the portion of the first diaphragm 212 corresponding to the cavity may have a textured film structure, or only the portion of the second diaphragm 216 corresponding to the cavity may have a textured film structure. For example, as shown... Figure 17 As shown, the textured structure refers to the protrusions on the upper surface of the diaphragm (the surface away from the first substrate 210), such as annular protrusions. The textured structure can increase the effective area of ​​the diaphragm, reduce the air damping of the diaphragm, and improve the stiffness of the diaphragm, thereby improving the sensitivity of the MEMS device.

[0115] In one example, since the connecting post 230 connects the first diaphragm 212 and the second diaphragm 216 respectively, the first diaphragm 212 and the second diaphragm 216 will undergo the same deformation when receiving an external sound signal. The first diaphragm 212 and the first backplate layer 214 constitute a first variable capacitor structure, the second diaphragm 216 and the first backplate layer 214 constitute a second variable capacitor structure, and the second diaphragm 216 and the second backplate layer 218 constitute a third variable capacitor structure. Exemplarily, the first and second variable capacitor structures can constitute a differential output signal of a MEMS device, and the second and third variable capacitor structures can also constitute a differential output signal of a MEMS device. These two differential output signals can be output separately or combined, thereby improving sensitivity and signal-to-noise ratio. Exemplarily, a bias voltage can be applied to the first backplate layer 214 or the second diaphragm 216. In one example, such as... Figure 18As shown, the first diaphragm 212 and the second diaphragm 216 are electrically connected via the first conductive contact 291, and the first conductive layer 2142 and the second conductive layer 2182 are electrically connected via the second conductive contact 292. Exemplarily, the output signals of the first diaphragm 212 and the second diaphragm 216 can be combined with the output signals of the first conductive layer 2142 and the second conductive layer 2182 to form a differential signal for output in a MEMS device. Exemplarily, the sidewalls of both the first conductive contact 291 and the second conductive contact 292 are covered with insulating material. Exemplarily, the first conductive contact 291 and the second conductive contact 292 are also bonded together using the aforementioned bonding steps.

[0116] This concludes the description of the key steps in the manufacturing method of the MEMS device of this application. The manufacturing of a complete MEMS device may include other steps, which will not be elaborated here. It is worth mentioning that the order of the above steps can be adjusted without conflict.

[0117] In summary, the MEMS device manufacturing method of this application embodiment forms a MEMS device with dual diaphragm / dual backplane layers through bonding process. While improving performance, sensitivity and signal-to-noise ratio, it can simplify the manufacturing process, reduce costs, improve efficiency and yield, improve uniformity, avoid problems such as warping, and also adjust the vacuum level.

[0118] Example 2

[0119] This application also provides a MEMS device, which is manufactured by the method described in the first embodiment above.

[0120] The embodiments of this application form MEMS devices with dual diaphragm / dual backplane layers through bonding processes. This improves performance, sensitivity, and signal-to-noise ratio while simplifying the manufacturing process, reducing costs, increasing efficiency and yield, and improving uniformity and avoiding problems such as warping.

[0121] Although several embodiments have been described herein, it should be understood that many other modifications and embodiments will arise in the mind of those skilled in the art, all of which will fall within the spirit and scope of the concept disclosed herein. More specifically, various modifications and changes may be made in terms of the arrangement and / or components of the subject matter within the scope of this disclosure, the drawings, and the appended claims. In addition to modifications and changes in the components and / or arrangement, the use of alternative methods will also be obvious to those skilled in the art.

Claims

1. A method of manufacturing a MEMS device, characterized by, The method includes: A first substrate and a second substrate are provided, wherein a first bonding structure is formed on a first surface of one of the first substrate and a second bonding structure is formed on the first surface of the other substrate; The first bonding structure and the second bonding structure are bonded together to obtain a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, a second diaphragm, a fourth sacrificial layer, a second backplate layer, and a fifth sacrificial layer stacked from the first bonding structure to the second bonding structure. A first cavity is formed between the first diaphragm and the second diaphragm. A plurality of first release holes are formed in the first backplate layer and a plurality of connecting posts are formed in the first cavity. The connecting posts pass through the first release holes and connect the first diaphragm and the second diaphragm respectively. Remove the second substrate, remove the portion of the first substrate corresponding to the first cavity from the second surface of the first substrate to form a back cavity, and remove a portion of the sacrificial layer: when the first bonding structure is formed on the first surface of the first substrate, remove the fifth sacrificial layer and the first sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity; when the first bonding structure is formed on the first surface of the second substrate, remove the first sacrificial layer and the fifth sacrificial layer exposed in the back cavity, and remove a portion of the fourth sacrificial layer to form a second cavity corresponding to the first cavity.

2. The manufacturing method according to claim 1, characterized in that, The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, and a third sacrificial layer stacked together. A first cavity is formed on the first diaphragm, and the connecting post is formed within the first cavity. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second diaphragm stacked together. In the bonding step, the third sacrificial layer and the connecting post are bonded to the second diaphragm; or The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, and a first sub-diaphragm, all stacked together. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second sub-diaphragm, all stacked together. In the bonding step, the first sub-diaphragm and the second sub-diaphragm are bonded together, and the first sub-diaphragm and the second sub-diaphragm constitute the second diaphragm; or The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, and a second diaphragm stacked together; the second bonding structure includes a fifth sacrificial layer, a second backplate layer, and a fourth sacrificial layer stacked together; and in the bonding step, the second diaphragm is bonded to the fourth sacrificial layer; or The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, and a first sub-sacrificial layer stacked together. The second bonding structure includes a fifth sacrificial layer, a second backplate layer, and a second sub-sacrificial layer stacked together. In the bonding step, the first sub-sacrificial layer and the second sub-sacrificial layer are bonded together, and the first sub-sacrificial layer and the second sub-sacrificial layer constitute the fourth sacrificial layer; or The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, and a fourth sacrificial layer stacked together; the second bonding structure includes a fifth sacrificial layer and a second backplate layer stacked together; and in the bonding step, the fourth sacrificial layer is bonded to the second backplate layer; or The first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, a third sacrificial layer, the first diaphragm, a fourth sacrificial layer, and a first sub-backplate layer stacked together. The second bonding structure includes a fifth sacrificial layer and a second sub-backplate layer stacked together. In the bonding step, the first sub-backplate layer and the second sub-backplate layer are bonded together, and the first sub-backplate layer and the second sub-backplate layer constitute the second backplate layer.

3. The manufacturing method according to claim 1, characterized in that, When the first bonding structure includes a first sacrificial layer, a first diaphragm, a second sacrificial layer, a first backplate layer, and a third sacrificial layer stacked together, a first cavity is formed on the first diaphragm, and a connecting post is formed in the first cavity, and the second bonding structure includes a fifth sacrificial layer, a second backplate layer, a fourth sacrificial layer, and a second diaphragm stacked together, a connecting layer is also formed on the surface of the connecting post used for bonding with the second diaphragm, and the width of the connecting layer is greater than the width of the connecting post.

4. The manufacturing method according to claim 2, characterized in that, The first backsheet layer includes a first dielectric layer, a first conductive layer, and a second dielectric layer stacked from the second sacrificial layer toward the third sacrificial layer; The second backsheet layer includes a third dielectric layer, a second conductive layer, and a fourth dielectric layer stacked from the fourth sacrificial layer toward the fifth sacrificial layer; The bonding step involves bonding the first sub-backplane layer to the second sub-backplane layer, including: The first sub-backplane layer includes a first sub-dielectric layer, and the second sub-backplane layer includes a second sub-dielectric layer, a second conductive layer, and the fourth dielectric layer. In the bonding step, the first sub-dielectric layer and the second sub-dielectric layer are bonded together, and the first sub-dielectric layer and the second sub-dielectric layer constitute the third dielectric layer; or The first sub-backplane layer includes the third dielectric layer, and the second sub-backplane layer includes the second conductive layer and the fourth dielectric layer. In the bonding step, the third dielectric layer and the second conductive layer are bonded; or The first sub-backplane layer includes the third dielectric layer and the first sub-conductive layer, and the second sub-backplane layer includes the second sub-conductive layer and the fourth dielectric layer. In the bonding step, the first sub-conductive layer and the second sub-conductive layer are bonded together, and the first sub-conductive layer and the second sub-conductive layer constitute the second conductive layer; or The first sub-backplane layer includes the third dielectric layer and the second conductive layer, and the second sub-backplane layer includes the fourth dielectric layer. In the bonding step, the second conductive layer is bonded to the fourth dielectric layer; or The first sub-backplane layer includes the third dielectric layer, the second conductive layer, and the third sub-dielectric layer. The second sub-backplane layer includes the fourth sub-dielectric layer. In the bonding step, the third sub-dielectric layer and the fourth sub-dielectric layer are bonded together, and the third sub-dielectric layer and the fourth sub-dielectric layer constitute the fourth dielectric layer.

5. The manufacturing method according to claim 4, characterized in that, In the bonding step, the material combination of the bonding surfaces of the first bonding structure and the second bonding structure is at least one of the following: amorphous silicon-amorphous silicon, silicon nitride-oxide, silicon nitride-amorphous silicon, silicon nitride-polycrystalline silicon, silicon nitride-silicon nitride, polycrystalline silicon-polycrystalline silicon, amorphous silicon-polycrystalline silicon, oxide-amorphous silicon, oxide-polycrystalline silicon, and oxide-oxide.

6. The manufacturing method according to claim 4, characterized in that, The first diaphragm and the second diaphragm are electrically connected through a first conductive contact, and the first conductive layer and the second conductive layer are electrically connected through a second conductive contact.

7. The manufacturing method according to claim 1, characterized in that, Before performing the bonding step, the method further includes: An anti-sputtering layer is formed on the bonding surface of the first bonding structure and / or the bonding surface of the second bonding structure; or Activate the bonding surfaces of the first bonding structure and / or the bonding surfaces of the second bonding structure.

8. The manufacturing method according to claim 1, characterized in that, After performing the bonding step, the method further includes etching the first diaphragm, the connecting post, and the second diaphragm to form an exhaust hole penetrating the first diaphragm, the connecting post, and the second diaphragm, wherein the exhaust hole is not in communication with the first cavity.

9. The manufacturing method according to claim 1, characterized in that, The first diaphragm has a textured structure formed on the portion corresponding to the cavity, and / or the second diaphragm has a textured structure formed on the portion corresponding to the cavity.

10. A MEMS device, characterized in that, The MEMS device is manufactured using the method described in any one of claims 1-9.

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