MEMS structure and manufacturing method thereof, sensor and electronic equipment

Abstract

The invention discloses an MEMS structure and a manufacturing method thereof, a sensor and electronic equipment. The MEMS structure comprises a substrate, a first movable electrode, a fixed electrode, a second movable electrode and a plurality of supporting columns, the fixed electrode is provided with a plurality of first through holes, two ends of each support column are respectively connected with the first movable electrode and the second movable electrode, so that the first movable electrode, the fixed electrode and the second movable electrode form a variable capacitor, and the plurality of support columns respectively penetrate through the fixed electrode and are arranged at intervals; a cavity between the first movable electrode and the second movable electrode is divided into at least two closed first cavities; second cavities are formed between the first movable electrode and the substrate, and the air pressure value in each first cavity is set to be different from the air pressure value of the second cavity. The MEMS structure provided by the invention is more accurate in detection of the external pressure.

Description

Technical Field

[0001] The present application belongs to the technical field of electronic equipment, and specifically relates to a MEMS structure and a manufacturing method thereof, a sensor and an electronic device. Background Art

[0002] Currently, the mainstream differential or gauge pressure MEMS sensors on the market are mainly piezoresistive pressure MEMS sensors, but these sensors have disadvantages such as low sensitivity and large temperature drift. Compared with piezoresistive pressure MEMS sensors, capacitive pressure MEMS sensors use capacitance changes to detect pressure. They have the advantages of high sensitivity, good temperature stability, and good long-term stability and reliability. However, capacitive pressure MEMS sensors can also cause zero-point drift in the chip output due to factors such as ambient temperature and packaging stress, which in turn affects output accuracy. Summary of the Invention

[0003] The present application aims to provide a MEMS structure and a manufacturing method thereof, a sensor and an electronic device, which at least solve one of the problems of the background technology.

[0004] In order to solve the above technical problems, this application is implemented as follows:

[0005] According to a first aspect of the present application, there is provided a MEMS structure, comprising:

[0006] A substrate, a first movable electrode, a fixed electrode, a second movable electrode, and a plurality of support pillars are sequentially stacked.

[0007] The fixed electrode is provided with a plurality of first through holes, and both ends of each of the support pillars are respectively connected to the first movable electrode and the second movable electrode, so that the first movable electrode, the fixed electrode and the second movable electrode form a variable capacitor;

[0008] The plurality of support pillars respectively pass through the fixed electrodes and are spaced apart so that the cavity between the first movable electrode and the second movable electrode is divided into at least two closed first cavities;

[0009] A second cavity is formed between the first movable electrode and the substrate, and the air pressure value in each of the first cavities is set to be different from the air pressure value in the second cavity.

[0010] Optionally, the air pressure values ​​in the first cavities are set to be different.

[0011] Optionally, the volumes of the first cavities are different.

[0012] Optionally, the first cavities are evenly distributed between the first movable electrode and the second movable electrode.

[0013] Optionally, the first movable electrode is provided with a second through hole, and the second cavity is connected to the second movable electrode along the cavity between two adjacent support pillars through the second through hole.

[0014] Optionally, a third through hole is provided on the base, and the second cavity is connected to the external air through the third through hole.

[0015] Optionally, an insulating layer is provided on the surface of the substrate, and the first movable electrode, the fixed electrode and the second movable electrode are respectively stacked on the substrate with intervals through the insulating layer;

[0016] The first movable electrode, the fixed electrode, and the second movable electrode are respectively connected to the surface of the insulating layer and can be connected to an external circuit.

[0017] According to a second aspect of the present application, there is provided a method for manufacturing the MEMS structure according to the first aspect, comprising:

[0018] A first sacrificial layer, the first movable electrode, a second sacrificial layer, the fixed electrode and a third sacrificial layer are sequentially provided on the surface of the substrate, and a plurality of the first through holes are provided on the fixed electrode;

[0019] In the stacking direction, at least one support column connected to the surface of the first movable electrode is provided through the second sacrificial layer and the third sacrificial layer;

[0020] Disposing a second movable electrode on the surfaces of the support pillar and the third sacrificial layer;

[0021] removing the second sacrificial layer and the third sacrificial layer to form at least two first cavities separated from each other, and making the first cavities have a first air pressure value;

[0022] The first sacrificial layer is removed to form the second cavity, and the second cavity is made to have a second pressure value different from the first pressure value.

[0023] Optionally, first release holes are respectively provided on the second movable electrode at positions corresponding to the first cavities, and the second sacrificial layer and the third sacrificial layer are removed through the first release holes to form the first cavities;

[0024] After gas with a first pressure value is set in each of the first cavities through each of the first release holes, each of the first release holes is blocked.

[0025] Optionally, a second through hole is provided at a position of the first movable electrode corresponding to a position between two adjacent support pillars, and a second release hole is provided at a position of the second movable electrode corresponding to a position between two adjacent support pillars;

[0026] removing the second sacrificial layer and the third sacrificial layer between two adjacent support pillars through each of the second release holes, and removing the first sacrificial layer through each of the second release holes and each of the second through holes to form the second cavity;

[0027] After gas with a second pressure value is provided in the second cavity through each of the second release holes, each of the second release holes is sealed.

[0028] Optionally, a third through hole communicating with external air is provided on the substrate, and the first sacrificial layer is removed through the third through hole to form the second cavity.

[0029] According to a third aspect of the present application, a sensor is provided, comprising:

[0030] The MEMS structure according to the first aspect; or comprising:

[0031] A MEMS structure manufactured using the manufacturing method described in the second aspect.

[0032] According to a fourth aspect of the present application, there is provided an electronic device, comprising:

[0033] The sensor described in the third aspect.

[0034] In this application, a differential pressure capacitance MEMS structure is formed by providing a first cavity and a second cavity with different air pressure values ​​within the MEMS structure. In practical applications, when the MEMS structure senses external pressure, the MEMS structure and two movable electrodes can move up and down according to the difference between the external pressure and the pressure in the first cavity, while the fixed electrode remains stationary. This in turn changes the capacitance between the two movable electrodes and the fixed electrode to achieve pressure measurement, effectively reducing interference errors caused by factors such as temperature and external loads, and improving the output accuracy of the MEMS structure.

[0035] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0037] Figure 1 This is one of the side view structural diagrams of the MEMS structure provided in this application;

[0038] Figure 2 yes Figure 1 Cross-sectional view along the AA axis;

[0039] Figure 3 yes Figure 1 Cross-sectional view along the BB direction;

[0040] Figure 4 This is the second side view structural diagram of the MEMS structure provided by this application;

[0041] Figure 5 This is one of the flow charts of the method for manufacturing a MEMS structure provided in this application;

[0042] Figure 6 This is the second flow chart of the method for manufacturing the MEMS structure provided by the present application;

[0043] Figure 7 This is the third flow chart of the method for manufacturing a MEMS structure provided by this application;

[0044] Figure 8 This is the fourth flow chart of the method for manufacturing a MEMS structure provided by this application;

[0045] Figure 9 This is the fifth flow chart of the method for manufacturing the MEMS structure provided in this application.

[0046] Reference numerals:

[0047] 1. Substrate; 11. Third through hole; 2. First movable electrode; 21. Second through hole; 3. Fixed electrode; 31. First through hole; 4. Second movable electrode; 41. First release hole; 42. Second release hole; 43. First blocking structure; 44. Second blocking structure; 5. Support column; 51. First support column; 52. Second support column; 6. Pad; 7. First cavity; 8. Second cavity; 9. Insulating layer; 91. First sacrificial layer; 92. Second sacrificial layer; 93. Third sacrificial layer. DETAILED DESCRIPTION

[0048] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application are within the scope of protection of the present application.

[0049] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly refer to one or more of the features. Throughout the description of this application, unless otherwise specified, "plurality" means two or more. Furthermore, "and / or" in the specification and claims refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0050] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0052] The following combination Figure 1-Figure 5 The present invention describes a MEMS structure, a manufacturing method thereof, a sensor, and an electronic device according to embodiments of the present application.

[0053] like Figures 1 to 4 As shown, according to some embodiments of the present application, a MEMS structure is provided, including: a substrate 1, a first movable electrode 2, a fixed electrode 3 and a second movable electrode 4 stacked in sequence at intervals, and a plurality of support columns 5; the fixed electrode 3 is provided with a plurality of first through holes 31, and the two ends of each support column 5 are respectively connected to the first movable electrode 2 and the second movable electrode 4, so that the first movable electrode 2, the fixed electrode 3 and the second movable electrode 4 form a variable capacitor; the plurality of support columns 5 respectively pass through the fixed electrode 3 and are arranged at intervals, so that the cavity between the first movable electrode 2 and the second movable electrode 4 is divided into at least two closed first cavities 7; a second cavity 8 is formed between the first movable electrode 2 and the substrate 1, and the air pressure value in each first cavity 7 is set to be different from the air pressure value of the second cavity 8.

[0054] Specifically, in the present application, the first movable electrode 2 and the second movable electrode 4 are interconnected by a plurality of support columns 5, and the first movable electrode 2 and the second movable electrode 4 have a first capacitance value and a second capacitance value respectively with the fixed electrode 3. When the MEMS structure is subjected to external pressure, the first movable electrode 2 and the second movable electrode 4 can be deformed upward or downward at the same time, so that the distance between the first movable electrode 2 and the second movable electrode 4 and the fixed electrode 3 changes, thereby changing the magnitude of the first capacitance value and the second capacitance value. Pressure measurement is then achieved by changing the capacitance value between the two movable electrodes and the fixed electrode 3, so that the MEMS structure can form a differential pressure differential capacitance or gauge pressure differential capacitance sensor, effectively reducing the interference error caused by factors such as temperature and external load on the MEMS structure, and improving the measurement output accuracy of the MEMS structure.

[0055] In the above structure, each first cavity 7 can be set to a vacuum state, and the second cavity 8 can be set to a second air pressure value (such as atmospheric pressure or negative atmospheric pressure) that is not a vacuum state, so that the MEMS structure can feel the effect of external pressure. The first movable electrode 2 and the second movable electrode 4 are rigidly connected by multiple support columns 5, and will deform upward or downward at the same time, and the fixed electrode 3 in the middle is stationary. At this time, the MEMS structure can constitute a gauge pressure sensor.

[0056] When each first cavity 7 is set to a vacuum state and the second cavity 8 is connected to the external air, since the first movable electrode 2 and the second movable electrode 4 are rigidly connected by multiple support columns 5, when they sense the difference in pressure between the upper and lower surfaces of the MEMS structure, they will deform upward or downward at the same time, and the fixed electrode 3 remains stationary. At this time, the MEMS structure can constitute a differential pressure sensor.

[0057] In this embodiment, the shape of the support column 5 can be designed according to actual needs and can be a long strip, annular, etc. The distribution position of the first cavity 7 is related to the actual shape and distribution of the support column 5. The number, position, size, etc. of the first cavity 7 can be adjusted by adjusting the parameters of the support column 5, and this application does not impose any restrictions on this. The air pressure value of the first cavity 7 is not limited to a vacuum state; it is sufficient that the pressure value of the first cavity 7 and the second cavity 8 are different.

[0058] It should be noted that the first cavity 7 in the present application needs to be set to a sealed state. It can be sealed directly through the support column 5 and the first movable electrode 2, or it can be sealed with the assistance of other structures, and this is not limited here. In addition, the first movable electrode 2, the second movable electrode 4 and the fixed electrode 3 can all be made of conductive materials, such as polysilicon, the substrate 1 can be made of Si, and the support column 5 can be made of silicon oxide or silicon nitride. Optionally, the air pressure value in each first cavity 7 is set to different.

[0059] Specifically, in practical applications, the first movable electrode 2 and the second movable electrode 4 corresponding to each first cavity 7 can be considered to form multiple small variable capacitors with the fixed electrode 3. When the air pressure values ​​within each first cavity 7 are set to the same, their detection sensitivity to external pressure values ​​is roughly the same; when the air pressure values ​​within each first cavity 7 are set to different, the deformation of each first cavity 7 can be made different, thereby allowing the MEMS structure to have multiple different detection sensitivities simultaneously to adapt to complex scenarios and improve the environmental adaptability of the MEMS structure. Among them, when the air pressure values ​​within each first cavity 7 are different, they are also different from the pressure values ​​of the second cavity 8, respectively, to ensure the sensitivity of the MEMS structure.

[0060] Furthermore, in actual applications, the connection relationship between the electrodes inside the MEMS structure can be set as follows: when the air pressure in each first cavity 7 is set to the same, the first movable electrodes 2 corresponding to each first cavity 7 are connected in parallel to each other, serving as the first electrode of the entire MEMS structure, and the second movable electrodes 4 corresponding to each first cavity 7 are also connected in parallel to each other, serving as the second electrode of the entire MEMS structure. By connecting the first electrode and the second electrode to an external detection circuit, a Wheatstone bridge is formed to achieve the purpose of detecting the capacitance value between the first movable electrode 2 and the fixed electrode 3, and detecting the capacitance value between the second movable electrode 4 and the fixed electrode 3.

[0061] When the air pressure values ​​within each first cavity 7 are set to be different, an external circuit can be used to connect the voltage value between the first movable electrode 2 and the fixed electrode 3 corresponding to each first cavity 7, and the voltage value between the second movable electrode 4 and the fixed electrode 3 corresponding to each first cavity 7, respectively, to achieve Wheatstone bridge connection and detection. The specific design is based on actual needs and is not limited in this application.

[0062] Alternatively, as Figures 1 to 4 As shown, the volumes of the first cavities 7 are different.

[0063] Specifically, in this embodiment, the volume of each first cavity 7 also affects the setting of the air pressure value therein. In some structures, the volume of each first cavity 7 divided by each support column 5 can be adjusted by adjusting the position, shape, size, etc. of each support column 5 to adjust the air pressure value in each first cavity 7. When the volume in each first cavity 7 is set to be the same, it can be applied to a structure in which the air pressure value in each first cavity 7 is set to be the same, so as to facilitate the setting of the air pressure value. When the air pressure value in each first cavity 7 is set to be different, the pressure value can be adjusted by adjusting the volume of each first cavity 7 or the amount of gas filled, etc., and this application does not impose any restrictions on this.

[0064] Alternatively, as Figures 1 to 4 As shown, the first cavities 7 are evenly distributed between the first movable electrode 2 and the second movable electrode 4 .

[0065] Specifically, in practical applications, the distribution of the first cavities 7 is also related to the overall detection sensitivity of the MEMS structure. Evenly distributing the first cavities 7 can further improve the detection sensitivity of the MEMS structure. The even distribution of the first cavities 7 can be achieved by evenly distributing the support pillars 5 between the first movable electrode 2 and the second movable electrode 4.

[0066] Alternatively, as Figure 3 As shown, the first movable electrode 2 is provided with a second through hole 21 , and the second cavity 8 is connected to the second movable electrode 4 along the cavity between two adjacent support pillars 5 through the second through hole 21 .

[0067] Specifically, in this embodiment, the plurality of support columns 5 can be configured into different shapes according to actual needs, for example Figure 3 The illustrated structure allows the inner side of each support column 5 to cooperate with the first movable electrode 2, the second movable electrode 4, and the insulating layer 9 to form a sealed first cavity 7. The multiple support columns 5 are spaced apart from each other, so that a cavity or gap can be formed between two support columns 5, allowing the second cavity 8 to communicate with the second movable electrode 4 through the second through hole 21. This facilitates etching the second cavity 8 from the location of the second movable electrode 4 in actual production, reducing production costs and improving production efficiency.

[0068] The second through hole 21 is typically positioned between two adjacent support pillars 5, and the gap between the two adjacent support pillars 5 can be larger than the size of the second through hole 21. Furthermore, the second through hole 21 can be designed as a plurality of evenly spaced small holes, each with a diameter of 5 μm or less, to avoid a significant difference in stiffness between the first movable electrode 2 and the second movable electrode 4, thereby improving the performance of the MEMS structure.

[0069] Alternatively, as Figure 4 As shown, a third through hole 11 is provided on the base 1 , and the second cavity 8 is communicated with the external air through the third through hole 11 .

[0070] Specifically, in practical applications, connecting the second cavity 8 to the outside air allows the MEMS structure to form a differential pressure capacitive MEMS sensor. By providing a third through-hole 11 in the substrate 1, the second cavity 8 can be directly connected to the outside air. During the deformation of the first and second movable electrodes, the distance between the first movable electrode 2 and the fixed electrode 3 changes, resulting in a corresponding change in capacitance. Similarly, the distance between the second movable electrode 4 and the fixed electrode changes, resulting in a corresponding change in capacitance, thereby enabling the sensor's pressure detection function.

[0071] Alternatively, as Figures 1 to 4 As shown, an insulating layer 9 is provided on the surface of the substrate 1, and the first movable electrode 2, the fixed electrode 3 and the second movable electrode 4 are respectively stacked on the substrate 1 with intervals through the insulating layer 9; the first movable electrode 2, the fixed electrode 3 and the second movable electrode 4 are respectively led to the surface of the insulating layer 9 and can be connected to the external circuit respectively.

[0072] Specifically, in this embodiment, the first movable electrode 2, the fixed electrode 3, and the second movable electrode 4 are insulated from each other to prevent short circuits and improve the reliability of the MEMS structure. The insulating layer 9 can be made of silicon oxide or silicon nitride, without limitation. Furthermore, the first movable electrode 2, the fixed electrode 3, and the second movable electrode 4 are each wired to the surface of the insulating layer 9 to form a plurality of pads 6. The MEMS structure is connected to an external capacitive differential Wheatstone bridge circuit via each pad 6, further effectively reducing interference errors caused by factors such as temperature and external loads.

[0073] According to the second aspect provided by this application, Figures 5 to 9 As shown, a method for manufacturing a MEMS structure according to the second aspect is provided, comprising:

[0074] like Figure 5 As shown, a first sacrificial layer 91 , a first movable electrode 2 , a second sacrificial layer 92 , a fixed electrode 3 and a third sacrificial layer 93 are sequentially provided on the surface of the substrate 1 , and a plurality of first through holes 31 are provided on the fixed electrode 3 .

[0075] First, a substrate 1 is provided, and then Figure 5 In steps S01, S02, and S03, a first sacrificial layer 91 is deposited on the surface of the substrate 1, a first movable electrode 2 is deposited on the first sacrificial layer 91, a second sacrificial layer 92 is deposited on the first movable electrode 2, a fixed electrode 3 is deposited on the second sacrificial layer 92, and a third sacrificial layer 93 is deposited on the fixed electrode 3. After depositing the fixed electrode 3, the fixed electrode 3 can be patterned to provide a plurality of first through holes 31 to reduce the damping of the variable capacitor. Some of the plurality of first through holes 31 are used to connect the upper and lower sides of the fixed electrode 3, while others are used to penetrate the support pillar 5. The size and position of each first through hole 31 are set according to actual needs.

[0076] like Figure 6 As shown, in the stacking direction, at least one support column 5 connected to the surface of the first movable electrode 2 is provided through the second sacrificial layer 92 and the third sacrificial layer 93 ; and the second movable electrode 4 is provided on the surface of the support column 5 and the third sacrificial layer 93 .

[0077] refer to Figure 6In step S04, in the stacking direction of the above structure, a portion of the second sacrificial layer 92 and a portion of the third sacrificial layer 93 are removed by etching until the surface of the first movable electrode 2 is exposed, thereby forming a space for arranging the support pillars 5. The positions where the second sacrificial layer 92 and the third sacrificial layer 93 are removed can be matched according to the number and shape of the support pillars 5, and are not limited here. Figure 6 In S05, the second sacrificial layer 92 and the third sacrificial layer 93 are removed and a plurality of support pillars 5 are deposited and patterned. Figure 6 In step S06, the second movable electrode 4 is deposited and, if necessary, patterned. The first sacrificial layer 91, the second sacrificial layer 92, and the third sacrificial layer 93 can all be made of silicon oxide or silicon nitride. Each sacrificial layer forms the entire insulating layer 9 in the final MEMS structure.

[0078] like Figure 7 As shown, the second sacrificial layer 92 and the third sacrificial layer 93 are removed to form at least two first cavities 7 separated from each other, and the first cavities 7 have a first gas pressure value.

[0079] refer to Figure 7 In steps S07 and S08, release is performed at the set positions of the second sacrificial layer 92 and the third sacrificial layer 93 according to actual needs to form each first cavity 7. During this process, the air pressure value of each first cavity 7 can be set simultaneously. The first cavity 7 can be released by patterning a first release hole 41 on the second movable electrode 4. The air pressure value can be set by inflation or degassing, etc., which is not limited here.

[0080] like Figure 8 As shown, the first sacrificial layer 91 is removed to form a second cavity 8 , and the second cavity 8 has a second pressure value different from the first pressure value.

[0081] refer to Figure 8 In S09 and S011, as needed, the first sacrificial layer 91 between the first movable electrode 2 and the substrate 1 is released to form the second cavities 8. During this process, the air pressure of each second cavity 8 can be set simultaneously. The second cavities 8 can be released by patterning second release holes 42 on the second movable electrode 4 or the substrate 1. The air pressure can be set by, for example, inflating or deflating the air, without limitation.

[0082] Finally, reference Figure 9(Step S12) Metal interconnects and passivation layer deposition can be continued to achieve wiring of the MEMS structure, thereby facilitating electrical connection to external circuits. Passivation layer deposition can be performed after the sacrificial layer is released from the first cavity 7 and after the sacrificial layer is released from the second cavity 8 to protect the electrodes.

[0083] Optionally, refer to Figure 6 In S06, first release holes 41 are respectively provided on the second movable electrode 4 at positions corresponding to the first cavities 7, referring to Figure 7 S07 in the embodiment of the present invention is to remove the second sacrificial layer 92 and the third sacrificial layer 93 through each first release hole 41 to form a first cavity 7; Figure 7 In step S08, after gas having a first pressure is introduced into each first cavity 7 through each first release hole 41, each first release hole 41 is sealed. This arrangement simplifies the formation of the first cavity 7 and facilitates adjustment of the pressure within each first cavity 7. Subsequently, the first release holes 41 are sealed by depositing a passivation layer and an oxide layer at the first release holes 41 and then depositing a conductive material on the second movable electrode 4, thereby forming a first sealing structure 43 at each first release hole 41.

[0084] Optionally, refer to Figure 3 , a second through hole 21 is respectively provided at a position between two adjacent support pillars 5 (ie, the first support pillar 51 and the second support pillar 52) of the first movable electrode 2, and a reference Figure 8 In S09, second release holes 42 are respectively provided at positions between two adjacent support pillars 5 in the second movable electrode 4. The second through hole 21 can be provided by patterning the first movable electrode 2 after the first movable electrode 2 is deposited. Figure 5 The provision of the second through hole 21 and the second release hole 42 facilitates the release of the second cavity 8.

[0085] refer to Figure 8 In S10, the second sacrificial layer 92 and the third sacrificial layer 93 between two adjacent support pillars 5 are removed through each second release hole 42, and the first sacrificial layer 91 is removed through each second release hole 42 and each second through hole 21, thereby forming a second cavity 8. The second cavity 8 can be configured to be sealed or to be in communication with the outside air, so that the MEMS structure can form a differential pressure or gauge pressure sensor.

[0086] refer to Figure 8In S11, after gas having a second pressure is provided in the second cavity 8 through each second release hole 42, each second release hole 42 is sealed. The second release holes 42 can be sealed by depositing a passivation layer and an oxide layer at the second release holes 42 and then depositing a conductive material on the second movable electrode 4, thereby forming a second sealing structure 44 at each second release hole 42.

[0087] Optionally, refer to Figure 4 A third through hole 11 communicating with the outside air is provided on the substrate 1 , and the first sacrificial layer 91 is removed through the third through hole 11 to form a second cavity 8 .

[0088] Specifically, in this embodiment, the second cavity 8 is configured to communicate with the external air, so that the first sacrificial layer 91 can be released directly through the third through hole 11 on the substrate 1 , simplifying the release of the second cavity 8 .

[0089] According to a third aspect provided by the present application, a sensor is provided, comprising: the MEMS structure of the first aspect; or comprising: the MEMS structure manufactured by the manufacturing method of the second aspect.

[0090] Specifically, in this embodiment, the MEMS structure provided based on the first aspect of this application can constitute a differential pressure or gauge pressure sensor, so that the output accuracy of the sensor is higher and is not affected by the environment and external stress, thereby improving the detection accuracy and applicability of the sensor.

[0091] According to a fourth aspect of the present application, an electronic device is provided, comprising: the sensor according to the third aspect. The electronic device manufactured using the sensor according to the third aspect has a relatively accurate pressure detection function, thereby increasing the scope of application of the electronic device.

[0092] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0093] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A MEMS structure, characterized in that: include: A substrate, a first movable electrode, a fixed electrode, a second movable electrode, and a plurality of support pillars are sequentially stacked. The fixed electrode is provided with a plurality of first through holes, and both ends of each of the support pillars are respectively connected to the first movable electrode and the second movable electrode, so that the first movable electrode, the fixed electrode and the second movable electrode form a variable capacitor; The plurality of support pillars respectively pass through the fixed electrodes and are spaced apart so that the cavity between the first movable electrode and the second movable electrode is divided into at least two closed first cavities; A second cavity is formed between the first movable electrode and the substrate, and the air pressure value in each of the first cavities is set to be different from the air pressure value in the second cavity.

2. The MEMS structure according to claim 1, wherein: The air pressure values ​​in the first cavities are set to be different.

3. The MEMS structure according to claim 1, wherein: The volumes of the first cavities are different.

4. The MEMS structure according to claim 1, wherein: The first cavities are evenly distributed between the first movable electrode and the second movable electrode.

5. The MEMS structure according to claim 1, wherein: The first movable electrode is provided with a second through hole, and the second cavity is connected to the second movable electrode along the cavity between two adjacent support pillars through the second through hole.

6. The MEMS structure according to claim 1, wherein: The base is provided with a third through hole, and the second cavity is communicated with the external air through the third through hole.

7. The MEMS structure according to claim 1, wherein: An insulating layer is provided on the surface of the substrate, and the first movable electrode, the fixed electrode and the second movable electrode are respectively stacked on the substrate with intervals of the insulating layer; The first movable electrode, the fixed electrode, and the second movable electrode are respectively connected to the surface of the insulating layer and can be connected to an external circuit.

8. A method for manufacturing a MEMS structure according to any one of claims 1 to 7, characterized in that: include: A first sacrificial layer, the first movable electrode, a second sacrificial layer, the fixed electrode and a third sacrificial layer are sequentially provided on the surface of the substrate, and a plurality of the first through holes are provided on the fixed electrode; In the stacking direction, at least one support column connected to the surface of the first movable electrode is provided through the second sacrificial layer and the third sacrificial layer; Disposing a second movable electrode on the surfaces of the support pillar and the third sacrificial layer; removing the second sacrificial layer and the third sacrificial layer to form at least two first cavities separated from each other, and making the first cavities have a first air pressure value; The first sacrificial layer is removed to form the second cavity, and the second cavity is made to have a second pressure value different from the first pressure value.

9. The method for manufacturing a MEMS structure according to claim 8, wherein: providing first release holes on the second movable electrode at positions corresponding to the first cavities, respectively, and removing the second sacrificial layer and the third sacrificial layer through the first release holes to form the first cavities; After gas with a first pressure value is set in each of the first cavities through each of the first release holes, each of the first release holes is blocked.

10. The method for manufacturing a MEMS structure according to claim 8, wherein: A second through hole is provided at a position of the first movable electrode corresponding to a position between two adjacent support pillars, and a second release hole is provided at a position of the second movable electrode corresponding to a position between two adjacent support pillars; removing the second sacrificial layer and the third sacrificial layer between two adjacent support pillars through each of the second release holes, and removing the first sacrificial layer through each of the second release holes and each of the second through holes to form the second cavity; After gas with a second pressure value is provided in the second cavity through each of the second release holes, each of the second release holes is sealed.

11. The method for manufacturing a MEMS structure according to claim 8, wherein: A third through hole communicating with external air is provided on the substrate, and the first sacrificial layer is removed through the third through hole to form the second cavity.

12. A sensor, characterized in that: include: The MEMS structure according to any one of claims 1 to 7; or comprising: A MEMS structure manufactured using the manufacturing method according to any one of claims 8 to 11.

13. An electronic device, characterized in that: include: The sensor of claim 12.

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