MEMS device and manufacturing method therefor

Abstract

A MEMS device and a manufacturing method therefor. The method comprises: forming a first MEMS structure (100), comprising: providing a first substrate (101), forming a first sensing layer (103) on the first substrate (101), and sequentially forming a first cavity (107) and a second sensing layer (105) on the first sensing layer (103); forming a second MEMS structure (200), comprising: providing a second substrate (201), forming a third sensing layer (203) on the second substrate (201), and sequentially forming a second cavity (207) and a fourth sensing layer (205) on the third sensing layer (203); bonding the second sensing layer (105) and the fourth sensing layer (205) to form a common sensing layer; and removing the portion of the first substrate (101) corresponding to the first cavity (107), the first sensing layer (103) forming a movable sensing layer.

Description

MEMS device and manufacturing method thereof

[0001] Related applications

[0002] The present application claims priority to the Chinese patent application No. 202410712950.0, filed on June 3, 2024, and entitled “A MEMS device and manufacturing method thereof”, the contents of which are hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of semiconductor technology, and in particular to a MEMS device and manufacturing method thereof. BACKGROUND

[0004] Micro-Electro-Mechanical System (MEMS) technology is a high-tech that has developed rapidly in recent years. It uses advanced semiconductor manufacturing processes to realize batch manufacturing of sensors, drivers and other devices. Compared with corresponding traditional devices, MEMS devices have obvious advantages in size, power consumption, weight and price. On the market, the main application examples of MEMS devices include pressure sensors, accelerometers and silicon microphones, etc.

[0005] The existing capacitive pressure sensor mainly uses silicon surface micromachining technology to prepare the sensor structure by using thin film deposition, photolithography and etching process. The process is mainly concentrated in the surface layer area of the front surface of the wafer. A certain number of release holes are etched in the middle area of the upper plate by etching process, and then the corresponding area of the sacrificial layer is etched through the release hole to form a movable cavity position of the upper plate. Then the release hole of the upper plate is plugged by the hole plugging structure to form a sealed absolute pressure cavity for pressure measurement. However, the hole plugging process will form a convex structure on the flat sensitive membrane structure surface, which introduces uncontrollable stress factors, causing the key sensitive membrane structure to increase the measurement error due to stress. In addition, there are also failure conditions such as air leakage due to reliability problems in the long-term use of the sealed cavity, which seriously affects the service life and yield of the device. SUMMARY

[0006] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to try to limit the key features and necessary technical features of the claimed technical solutions, nor does it mean to try to determine the protection scope of the claimed technical solutions.

[0007] The present application provides a manufacturing method of a MEMS device, comprising:

[0008] forming a first MEMS structure, comprising:

[0009] providing a first substrate, forming a first sensing layer on the first substrate;

[0010] forming a first cavity and a second sensing layer on the first sensing layer in sequence;

[0011] forming a second MEMS structure, comprising:

[0012] providing a second substrate, forming a third sensing layer on the second substrate;

[0013] forming a second cavity and a fourth sensing layer on the third sensing layer in sequence;

[0014] bonding the second sensing layer and the fourth sensing layer to form a common sensing layer; and

[0015] removing a portion of the first substrate corresponding to the first cavity, so that the first sensing layer forms a movable sensing layer.

[0016] In some embodiments, the movable sensing layer and the common sensing layer form a movable capacitor, and the common sensing layer and the third sensing layer form a reference capacitor.

[0017] In some embodiments, forming a first cavity on the first sensing layer comprises:

[0018] forming a first sacrificial layer and a second sensing layer on the first sensing layer in sequence;

[0019] forming a plurality of first through holes on the second sensing layer;

[0020] removing a portion of the first sacrificial layer through the plurality of first through holes to form the first cavity.

[0021] In some embodiments, a plurality of second through holes are formed on the fourth sensing layer, the plurality of first through holes and the plurality of second through holes are arranged one-to-one, and after the second sensing layer and the fourth sensing layer are bonded, the plurality of first through holes and the plurality of second through holes are respectively penetrated, so that the first cavity and the second cavity form a common cavity.

[0022] In some embodiments, the second substrate is further thinned, so that the thickness of the second substrate ranges from 40um to 50um.

[0023] In some embodiments, the thickness of the first sensing layer, the second sensing layer, the third sensing layer and the fourth sensing layer ranges from 1um to 5um, and the first sensing layer, the second sensing layer, the third sensing layer and the fourth sensing layer adopt a doped polysilicon layer.

[0024] In some embodiments, before removing the portion of the first substrate corresponding to the first cavity, the method further comprises etching the first substrate to form a quadrangular support structure at the bottom of the first substrate, the quadrangular support structure being configured to fixedly connect the MEMS device to a packaging substrate.

[0025] In some embodiments, the method further comprises forming a metal wiring layer on the second substrate, the metal wiring layer being respectively connected to the third sensing layer, the common sensing layer and the movable sensing layer.

[0026] In some embodiments, forming the plurality of first vias in the second sensing layer comprises:

[0027] forming a patterned mask layer on the second sensing layer by a photolithography process, and etching the second sensing layer to form the plurality of first vias.

[0028] In some embodiments, forming the second cavity in the third sensing layer comprises:

[0029] forming a second sacrificial layer and a fourth sensing layer on the third sensing layer in sequence, forming a plurality of second vias in the fourth sensing layer, and removing a portion of the second sacrificial layer through the plurality of second vias to form the second cavity.

[0030] The present application also provides a MEMS device manufactured according to any one of the above methods, comprising: a first substrate, the first substrate having a first sensing layer, a first cavity, a common sensing layer, a second cavity, a third sensing layer and a second substrate formed in sequence on the first substrate; wherein the first substrate comprises an opening corresponding to the first cavity, so that the first sensing layer forms a movable sensing layer.

[0031] In some embodiments, the MEMS device comprises a pressure sensor, and the sensing layer comprises a pressure sensing membrane.

[0032] In some embodiments, the bottom of the first substrate is formed with a quadrangular support structure, the quadrangular support structure being configured to fixedly connect the MEMS device to a packaging substrate.

[0033] In some embodiments, the second substrate is further formed with a metal wiring layer, the metal wiring layer comprising metal traces and being respectively connected to the third sensing layer, the common sensing layer and the movable sensing layer.

[0034] According to the MEMS device and the manufacturing method thereof provided in the application, the stacked double-layer capacitor structure is prepared by using the heterogeneous bonding mode, the process is simple, the implementability is high, the prepared device structure does not need to be plugged, the problem of uneven sensing layer caused by plugging is avoided, the reliability problem of air leakage of the upper pressure sensing film of the sealed cavity caused by repeated movement of the pressure sensing is avoided, and the service life and yield of the device are improved. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0036] FIG. 1 is a flowchart of a manufacturing method of a MEMS device according to an embodiment of the present application.

[0037] FIGS. 2A-2F are cross-sectional schematic diagrams of structures obtained by sequentially implementing a manufacturing method of a MEMS device according to an embodiment of the present application.

[0038] FIG. 3 is a top view schematic diagram of a MEMS device according to an embodiment of the present application.

[0039] FIG. 4 is a structural schematic diagram of an electronic device including a MEMS device according to an embodiment of the present application. DETAILED DESCRIPTION

[0040] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid obscuring the present application, some technical features known in the art are not described.

[0041] It should be understood that the present application can be implemented in different forms, and should not be interpreted as being limited to the embodiments presented herein. On the contrary, these embodiments are provided to make the disclosure complete and complete, and to fully convey the scope of the present application to those skilled in the art. In the drawings, the size and relative size of the layers and regions can be exaggerated for clarity. The same reference signs represent the same elements throughout.

[0042] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0043] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0045] For a thorough understanding of the present application, reference should be made to the following detailed description together with the accompanying drawings, in which:

[0046] The application provides a manufacturing method of a MEMS device, as shown in Fig. 1, which comprises the following steps S110-S140.

[0047] Step S110: forming a first MEMS structure, comprising: providing a first substrate, forming a first sensing layer on the first substrate, sequentially forming a first cavity and a second sensing layer on the first sensing layer.

[0048] Step S120: forming a second MEMS structure, comprising: providing a second substrate, forming a third sensing layer on the second substrate, sequentially forming a second cavity and a fourth sensing layer on the third sensing layer.

[0049] Step S130: bonding the second sensing layer and the fourth sensing layer to form a common sensing layer.

[0050] Step S140: removing a part of the first substrate corresponding to the first cavity, so that the first sensing layer forms a movable sensing layer.

[0051] The manufacturing method of the MEMS device of the application is described in detail below with reference to Figs. 2A-2F, which are cross-sectional schematic views of structures obtained in sequence in the manufacturing method of the MEMS device according to an embodiment of the application.

[0052] Firstly, step S110 is performed, as shown in Figs. 2A-2B, to form a first MEMS structure 100, which specifically comprises the following steps: providing a first substrate 101, forming a first sensing layer 103 on the first substrate 101, and sequentially forming a first cavity 107 and a second sensing layer 105 on the first sensing layer 103.

[0053] Exemplarily, the step of forming the first cavity 107 on the first sensing layer 103 comprises: sequentially forming a first sacrificial layer 104 and a second sensing layer 105 on the first sensing layer 103; forming a plurality of first through holes 106 on the second sensing layer 105; and removing part of the first sacrificial layer 104 through the plurality of first through holes 106 to form the first cavity 107.

[0054] In one embodiment, as shown in FIG. 2A, a first substrate 101 is provided, which can be any suitable semiconductor substrate, such as a silicon substrate, which can also be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP or other III / V compound semiconductor, including a multi-layer structure of these semiconductor materials, etc., or a silicon-on-insulator (SOI), a silicon-on-silicon-on-insulator (SSOI), a silicon-germanium-on-insulator (S-SiGeOI), a silicon-germanium-on-insulator (SiGeOI), and a germanium-on-insulator (GeOI), or can also be a double side polished wafer (DSP), or a ceramic substrate such as an aluminum oxide, a quartz or a glass substrate, etc.

[0055] In one embodiment, as shown in FIG. 2A, a first insulating layer 102, a first sensing layer 103, a first sacrificial layer 104 and a second sensing layer 105 are sequentially formed on the first substrate 101. The material of the first insulating layer 102 includes but is not limited to an oxide layer, and the method of forming the first insulating layer 102 can use any existing technology known to those skilled in the art, such as thermal oxidation, vapor deposition, etc. The material of the first sensing layer 103 and the second sensing layer 105 includes but is not limited to doped polysilicon, and the thickness of the first sensing layer 103 and the second sensing layer 105 ranges from 1 um to 5 um. The material of the first sacrificial layer 104 includes but is not limited to an oxide layer, and the thickness of the first sacrificial layer 104 can be set as needed, and the distance between the first sensing layer 103 and the second sensing layer 105 is controlled by controlling the thickness of the first sacrificial layer 104, thereby controlling the capacitance value between the first sensing layer 103 and the second sensing layer 105. The forming process of the first sensing layer 103, the first sacrificial layer 104 and the second sensing layer 105 can use any existing technology known to those skilled in the art, such as one of low pressure chemical vapor deposition (LPCVD), laser ablation deposition (LAD) and selective epitaxial growth (SEG) formed by chemical vapor deposition (CVD) method, physical vapor deposition (PVD) method or atomic layer deposition (ALD) method, or one of low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD) and plasma enhanced chemical vapor deposition (PECVD).

[0056] In one embodiment, as shown in FIG. 2B, a plurality of first vias 106 are formed on the second sensing layer 105. Specifically, a patterned mask layer (not shown) is formed on the second sensing layer 105 by a photolithography process, and then the second sensing layer 105 is etched to form the plurality of first vias 106. The method of etching the second sensing layer 105 can employ any prior art known to those skilled in the art, and in some embodiments, dry etching is employed. Dry etching includes, but is not limited to, reactive ion etching (RIE), ion beam etching, plasma etching, laser ablation, or any combination of these methods.

[0057] In one embodiment, the first sacrificial layer 104 is etched through the plurality of first vias 106 to form the first cavity 107 and a first support portion 104' surrounding the first cavity. The method of etching the first sacrificial layer 104 can employ any prior art known to those skilled in the art, and in some embodiments, wet etching is employed. The solution of wet etching is selective, and for the case that the first sacrificial layer 104 is silicon oxide, the first sensing layer 103 and the second sensing layer 105 are doped polysilicon, the solution of wet etching can be selected as a BOE solution, which is made of HF, NH4F and deionized water.

[0058] In step S120, a second MEMS structure 200 is formed, which specifically includes the following steps: providing a second substrate 201, and forming a third sensing layer 203 on the second substrate 201; sequentially forming a second cavity 207 and a fourth sensing layer 205 on the third sensing layer 203.

[0059] For example, the step of forming the second cavity 207 on the third sensing layer 203 includes: sequentially forming a second sacrificial layer 204 and a fourth sensing layer 205 on the third sensing layer 203; forming a plurality of second vias 206 on the fourth sensing layer 205; and removing part of the second sacrificial layer 204 through the plurality of second vias 206 to form the second cavity 207.

[0060] The method of forming the second MEMS structure 200 can refer to the method of forming the first MEMS structure 100 described above, which will not be repeated here.

[0061] In step S130, as shown in FIG. 2C, the second sensing layer 105 and the fourth sensing layer 205 are bonded to form a common sensing layer.

[0062] In one embodiment, before the second sensing layer 105 is bonded with the fourth sensing layer 205, the above method can further include chemical mechanical polishing the second sensing layer 105 and the fourth sensing layer 205 to make the surfaces of the second sensing layer 105 and the fourth sensing layer 205 meet the bonding requirements. Then the second sensing layer 105 and the fourth sensing layer 205 are bonded with each other, thereby realizing the bonding of the first MEMS structure 100 and the second MEMS structure 200.

[0063] In one embodiment, the plurality of first through holes 106 formed on the second sensing layer 105 and the plurality of second through holes 206 formed on the fourth sensing layer 205 are arranged one-to-one corresponding. After the second sensing layer 105 and the fourth sensing layer 205 are bonded, the plurality of first through holes 106 and the plurality of second through holes 206 are respectively penetrated, so that the first cavity 107 and the second cavity 207 form a common cavity. Since the second sensing layer 105 and the fourth sensing layer 205 are bonded by a vacuum bonding process, the common cavity formed by the first cavity 107 and the second cavity 207 maintains a vacuum state or a low pressure state close to vacuum, for example, the air pressure in the cavity is less than 10 Pa.

[0064] In one embodiment, the method can further include the step of thinning the second substrate 201. Specifically, the second substrate 201 is thinned by chemical mechanical polishing (CMP) to make the thickness of the second substrate 201 in the range of 40-50 um. By keeping the second substrate 201 with a larger thickness, the third sensing layer 203 is prevented from deforming, thereby ensuring the non-deformation state of the second cavity 207. The third sensing layer 203 and the common sensing layer form a fixed capacitor that does not change with pressure, thereby serving as a reference capacitor.

[0065] Step S140 is performed, as shown in FIGS. 2D-2E, the portion of the first substrate 101 corresponding to the first cavity 107 is removed, so that the first sensing layer 103 forms a movable sensing layer.

[0066] For example, before the portion of the first substrate 101 corresponding to the first cavity 107 is removed, the above method can further include etching the first substrate 101 to form a four-corner support structure 108 at the bottom of the first substrate 101, the four-corner support structure 108 includes four support columns (not shown) arranged at the four corners of the bottom of the first substrate 101, the four support columns are independent of each other, as shown in FIG. 3, the four-corner support structure 108 is used to fixedly connect the MEMS device to a packaging substrate.

[0067] In one embodiment, as shown in FIG. 2D, a four-corner support structure 108 is formed at the bottom of the first substrate 101. Specifically, a patterned mask layer (not shown) is formed on the first substrate 101 by a photolithography process, and then the first substrate 101 is etched to form the four-corner support structure 108. The method of etching the first substrate 101 can employ any prior art known to those skilled in the art, and in some embodiments, dry etching is employed. Dry etching includes, but is not limited to, reactive ion etching (RIE), ion beam etching, plasma etching, laser ablation, or any combination of these methods.

[0068] In one embodiment, as shown in FIG. 2E, the portion of the first substrate 101 corresponding to the first cavity 107 is etched to form an opening 109. The method of etching the first substrate 101 can employ any prior art known to those skilled in the art, and in some embodiments, deep reactive ion etching (DRIE) is employed. Specifically, a gas of silicon hexafluoride (SF6 / C4F8) is selected as the process gas, and a radio frequency power source is applied to cause the silicon hexafluoride to react to form a high ionization. In the etching step, the working pressure is controlled in the range of 20 mTorr to 80 mTorr, the radio frequency power is 600 W, the radio frequency frequency is 13.5 MHz, and the direct current bias can be continuously controlled within -500 V-1000 V to ensure the need for anisotropic etching. The deep reactive ion etching system can select a commonly used device in the art, and is not limited to a certain model.

[0069] The deep reactive ion etching (DRIE) described above stops at the first insulating layer 102 or the first sensing layer 103, so that the first sensing layer 103 forms a movable sensing layer, and the movable sensing layer and the common sensing layer form a movable capacitor. Taking the MEMS device as a pressure sensor as an example, the sensing layers described above are all pressure sensing films. When the MRMS pressure sensor is in operation, the movable sensing layer deforms, and the movable capacitor formed by the movable sensing layer and the common sensing layer is used to measure the pressure. The reference capacitor formed by the third sensing layer 203 and the common sensing layer serves as a reference, thereby improving the measurement accuracy of the MEMS device.

[0070] As shown in FIG. 2F, the method can further include a step of forming a metal wiring layer 208 on the second substrate 201, which is connected to the third sensing layer 203, the common sensing layer, and the movable sensing layer, respectively.

[0071] In one embodiment, the material of the metal wiring layer 208 is generally aluminum or gold. The metal wiring layer 208 includes metal traces and PAD structures, which are connected to the third sensing layer, the common sensing layer, and the movable sensing layer, respectively, to output a test signal.

[0072] The key steps of the method for manufacturing the MEMS device of the present application are introduced above. Other processes may be needed for the complete device preparation, which are not described here.

[0073] It is worth mentioning that the order of the above steps is only an example. The order of the above steps can be changed or alternated without conflict.

[0074] The present application also provides a MEMS device manufactured by the above method, as shown in FIGS. 2F and 3. The MEMS device comprises:

[0075] A first substrate 101, on which a first sensing layer 103, a first cavity 107, a common sensing layer, a second cavity 207, a third sensing layer 203 and a second substrate 201 are sequentially formed; wherein the first substrate 101 comprises an opening 109 arranged corresponding to the first cavity 107, so that the first sensing layer 103 forms a movable sensing layer.

[0076] In an embodiment, the first substrate 101 can be any suitable semiconductor substrate, such as a silicon substrate. The bottom of the first substrate 101 is formed with a four-corner support structure 108 for fixedly connecting the MEMS device to a packaging substrate. The first substrate 101 further comprises an opening 109 arranged corresponding to the first cavity 107, which exposes the first insulating layer 102 or the first sensing layer 103, so that the first sensing layer 103 forms a movable sensing layer, and the movable sensing layer and the common sensing layer form a movable capacitor.

[0077] In one embodiment, the first substrate 101 is sequentially formed with the first insulating layer 102, the first sensing layer 103, the first cavity 107, the common sensing layer, the second cavity 207, the third sensing layer 203, the second insulating layer 202 and the second substrate 201. The material of the first insulating layer 102 and the second insulating layer 202 includes but is not limited to an oxide layer, and the thickness of the first insulating layer 102 and the second insulating layer 202 is generally less than the thickness of the first sensing layer 103 and the third sensing layer 203. The material of the first sensing layer 103, the common sensing layer and the third sensing layer 203 includes but is not limited to doped polysilicon, the thickness of the first sensing layer 103 and the third sensing layer 203 ranges from 1 um to 5 um, and the thickness of the common sensing layer is greater than the thickness of the first sensing layer 103 and the third sensing layer 203. The periphery of the first cavity 107 and the second cavity 207 is respectively the first support part 104' supporting the first cavity and the second support part 204' supporting the second cavity, and the material of the first support part 104' and the second support part 204' includes but is not limited to silicon oxide. The thickness of the first support part 104' and the second support part 204' can be set as needed, and the thickness of the first support part 104' and the second support part 204' is controlled to control the distance between the first cavity 107 and the second cavity 207, and further control the capacitance value between the first sensing layer 103 and the common sensing layer and the capacitance value between the second sensing layer 203 and the common sensing layer.

[0078] In one embodiment, a plurality of first through holes 106 formed on the second sensing layer 105 are arranged one by one with a plurality of second through holes 206 formed on the fourth sensing layer 205, and after the second sensing layer 105 and the fourth sensing layer 205 are bonded to form a common sensing layer, the plurality of first through holes 106 and the plurality of second through holes 206 are respectively penetrated, and the first cavity 107 and the second cavity 207 form a common cavity. The common cavity formed by the first cavity 107 and the second cavity 207 maintains a vacuum state or a low pressure state close to vacuum, for example, the air pressure in the cavity is less than 10 Pa.

[0079] In one embodiment, the thickness of the second substrate 201 ranges from 40 um to 50 um. Since the second substrate 201 maintains a relatively large thickness, the third sensing layer 203 is prevented from deforming, and the second cavity 207 is ensured to be in a non-deformed state, and the third sensing layer 203 and the common sensing layer constitute a reference capacitor. By simultaneously arranging a movable capacitor and a reference capacitor in the MEMS device, the sensitivity and anti-interference ability of the MEMS device can be improved.

[0080] In one embodiment, the second substrate 201 is further formed with a metal wiring layer 208, the metal wiring layer 208 includes metal traces and PAD structures, and is respectively connected to the third sensing layer, the common sensing layer and the movable sensing layer to output a test signal.

[0081] The application also provides an electronic device, as shown in FIG. 4, comprising a packaging substrate 400, and a MEMS device as described above, which is fixed on the packaging substrate 400.

[0082] In one embodiment, the movable sensing layer film is packaged downward by fixing the MEMS device on the packaging substrate 400 through the four-corner support structure 108, as shown in FIG. 4, which avoids the problem of surface contamination caused by packaging the movable sensing layer film upward, improves the reliability of the MEMS device, and prolongs the service life of the MEMS device.

[0083] In one embodiment, the four-corner support structure 108 of the MEMS device is fixed on the packaging substrate 400 through the four-corner dispensing method. The conventional packaging method is usually to glue the bottom of the MEMS device as a whole or to glue the edge of the MEMS device as a whole, and then bond with the packaging substrate 400. Since the contact area of the MEMS device and the packaging substrate 400 is large, and the thermal expansion coefficients of the MEMS device and the packaging substrate 400 are different, the volume change caused by the change of the environmental temperature during the use of the MEMS device is also large, and the deformation stress will be transmitted to the inside of the MEMS device, resulting in errors. The application forms a structure with support columns only at the four corners of the bottom by performing two-step etching on the first substrate 101, as shown in FIG. 3, and only bonds at the four corner regions during packaging, which uniformly deforms and avoids introducing stress, and has good temperature stability. The elevated hollow structure between the four-corner support structures 108 can form a pressure transmission channel, and the pressure is transmitted to the surface of the movable sensing film at the center bottom of the MEMS device.

[0084] According to the MEMS device and the manufacturing method thereof provided by the application, the stacked double-layer capacitor structure is prepared by using the heterogeneous bonding mode, the process is simple, the implementability is high, the prepared device structure does not need to be plugged, the problem of uneven sensing layer caused by plugging is avoided, the reliability problem of air leakage of the plugging structure caused by repeated movement of the pressure sensing film on the sealed cavity is also avoided, and the service life and yield of the device are improved.

[0085] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0086] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific and detailed manner, but should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these are all within the scope of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A method for manufacturing a micro-electro-mechanical system (MEMS) device, comprising: forming a first MEMS structure, including: providing a first substrate, and forming a first sensing layer on the first substrate; forming a first cavity and a second sensing layer on the first sensing layer in sequence; forming a second MEMS structure, including: providing a second substrate, and forming a third sensing layer on the second substrate; forming a second cavity and a fourth sensing layer on the third sensing layer in sequence; bonding the second sensing layer and the fourth sensing layer to form a common sensing layer; and removing a portion of the first substrate corresponding to the first cavity to form the first sensing layer as a movable sensing layer. 2.The method of claim 1, wherein the movable sensing layer and the common sensing layer form a movable capacitor, and the common sensing layer and the third sensing layer form a reference capacitor. 3.The method of claim 1, wherein forming a first cavity on the first sensing layer includes: forming a first sacrificial layer and a second sensing layer on the first sensing layer in sequence; forming a plurality of first vias on the second sensing layer; removing a portion of the first sacrificial layer through the plurality of first vias to form the first cavity. 4.The method of claim 3, wherein the fourth sensing layer is formed with a plurality of second vias, the plurality of first vias and the plurality of second vias are arranged one-to-one, and after bonding the second sensing layer and the fourth sensing layer, the plurality of first vias and the plurality of second vias are respectively penetrated, so that the first cavity and the second cavity form a common cavity. 5.The method of claim 1, further comprising thinning the second substrate to have a thickness ranging from 40um to 50um. 6.The method of claim 1, wherein the first sensing layer, the second sensing layer, the third sensing layer, and the fourth sensing layer have a thickness ranging from 1um to 5um, and are made of a doped polysilicon layer. 7.The method of claim 1, before removing the portion of the first substrate corresponding to the first cavity, the method further comprises: etching the first substrate to form a quadrangular support structure at a bottom of the first substrate, the quadrangular support structure being used to fixedly connect the MEMS device to a packaging substrate. 8.The method of claim 5, further comprising forming a metal wiring layer on the second substrate, wherein the metal wiring layer is connected to the third sensing layer, the common sensing layer, and the movable sensing layer respectively. 9.The method of claim 3, wherein forming a plurality of first vias on the second sensing layer includes: forming a patterned mask layer on the second sensing layer by a photolithography process, and etching the second sensing layer to form the plurality of first vias.

10. The method of manufacturing a MEMS device according to claim 1, wherein forming a second cavity on the third sensing layer comprises: forming a second sacrificial layer and a fourth sensing layer on the third sensing layer in sequence, forming a plurality of second through holes on the fourth sensing layer, and removing part of the second sacrificial layer through the plurality of second through holes to form the second cavity.

11. A MEMS device manufactured according to any one of claims 1-10, comprising: a first substrate, on which a first sensing layer, a first cavity, a common sensing layer, a second cavity, a third sensing layer and a second substrate are formed in sequence; wherein the first substrate comprises an opening corresponding to the first cavity, so that the first sensing layer forms a movable sensing layer.

12. The MEMS device according to claim 11, wherein the MEMS device comprises a pressure sensor, and the sensing layer comprises a pressure sensing membrane.

13. The MEMS device according to claim 11, wherein a bottom of the first substrate is formed with a four-corner support structure for fixedly connecting the MEMS device to a packaging substrate.

14. The MEMS device according to claim 11, wherein the second substrate is further formed with a metal wiring layer comprising metal traces respectively connected to the third sensing layer, the common sensing layer and the movable sensing layer.

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