Micro differential pressure sensor and manufacturing method thereof

Abstract

The invention relates to a micro differential pressure sensor and a manufacturing method thereof. The micro differential pressure sensor comprises a sensing film; the substrate is located on one side of the sensing film, the substrate is provided with a cavity, and the sensing film is exposed out of the cavity; the cover plate electrode is arranged on the side, away from the substrate, of the sensing film, and the cover plate electrode comprises a cover plate layer and an electrode layer; the cover plate layer comprises a first cover plate part and a second cover plate part surrounding the first cover plate part, the electrode layer is arranged on the side, close to the sensing film, of the first cover plate part, and at least the electrode layer, the sensing film and the second cover plate part define a containing cavity; wherein the sensing film is configured to form capacitance between the sensing film and the electrode layer. The micro differential pressure sensor is low in manufacturing difficulty and simple and convenient in manufacturing process.

Description

Technical Field

[0001] The present disclosure relates to the technical field of sensor manufacturing, and in particular to a micro differential pressure sensor and a manufacturing method thereof. Background Art

[0002] Micro differential pressure sensors can be used to detect pressure difference changes in media such as gas / liquid, and provide functions such as detection and testing of medium pressure / flow rate.

[0003] Currently, in this field, the existing micro differential pressure sensors are difficult to manufacture and the manufacturing process is relatively complicated, which is not conducive to large-scale production.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The present disclosure aims to provide a micro differential pressure sensor and a manufacturing method thereof, wherein the micro differential pressure sensor has low manufacturing difficulty and simple manufacturing process.

[0006] The present disclosure provides a micro differential pressure sensor, comprising:

[0007] Sensing membrane;

[0008] A substrate is located on one side of the sensing film, and the substrate has a cavity, wherein the cavity exposes the sensing film;

[0009] A cover plate electrode is arranged on a side of the sensing film away from the substrate, and the cover plate electrode comprises: a cover plate layer and an electrode layer; the cover plate layer comprises a first cover plate portion and a second cover plate portion surrounding the first cover plate portion, the electrode layer is arranged on a side of the first cover plate portion close to the sensing film, and at least the electrode layer, the sensing film and the second cover plate portion form a receiving cavity;

[0010] Wherein, the sensing film is configured to form a capacitor with the electrode layer.

[0011] In an exemplary embodiment of the present disclosure, the material of the first cover plate portion and the material of the second cover plate portion are both glass.

[0012] In an exemplary embodiment of the present disclosure, the cover electrode further includes:

[0013] The second cover plate portion is provided with an electrical connection line, and the electrical connection line is electrically connected to the sensing film and the electrode layer through the connection through hole.

[0014] In an exemplary embodiment of the present disclosure, the cover electrode further includes:

[0015] A vent hole, the vent hole penetrates the first cover plate portion and the electrode layer along a first direction and is connected to the accommodating cavity, so as to connect the accommodating cavity with the medium to be measured;

[0016] Wherein, the first direction is the direction in which the first cover portion points to the sensing film.

[0017] In an exemplary embodiment of the present disclosure, there are a plurality of the air holes, and the plurality of the air holes are arranged in an array.

[0018] In an exemplary embodiment of the present disclosure, the electrical connection line includes a first connection line and a second connection line, and the connection through hole includes:

[0019] a first connecting through hole, wherein at least a portion of the first connecting wire is disposed in the first connecting through hole and is electrically connected to the sensing film;

[0020] A second connecting through hole, wherein at least a portion of the second connecting line is disposed in the second connecting through hole and is electrically connected to the electrode layer.

[0021] In an exemplary embodiment of the present disclosure, the first connecting line includes: a first body portion and a first extension portion, the first body portion is disposed in the first connecting through hole and is electrically connected to the sensing film, the first extension portion is located on a side of the second cover portion away from the sensing film and is connected to the first body portion;

[0022] The second connecting line includes: a second body portion and a second extension portion, the second body portion is disposed in the second connecting through hole and electrically connected to the electrode layer, and the second extension portion is located on a side of the second cover portion away from the sensing film and connected to the second body portion.

[0023] In an exemplary embodiment of the present disclosure, the first cover portion has a central area and an edge area, the edge area is arranged around the central area, and the distance between a portion of the first cover portion located in the central area and the sensing film is greater than the distance between a portion of the first cover portion located in the edge area and the sensing film.

[0024] In an exemplary embodiment of the present disclosure, the distance between a portion of the first cover portion located in the edge area and the sensing film decreases along the second direction;

[0025] The second direction is the direction from the central area to the edge area.

[0026] In an exemplary embodiment of the present disclosure, the cover electrode further includes:

[0027] The protective layer is arranged on a side of the cover layer away from the sensing film and at least covers the air holes.

[0028] In an exemplary embodiment of the present disclosure, the micro differential pressure sensor further includes:

[0029] The insulating layer is located between the substrate and the cover electrode and is arranged around the sensing film.

[0030] On one hand, the present disclosure provides a method for manufacturing a micro differential pressure sensor, comprising:

[0031] Providing a cover plate layer, the cover plate layer comprising a first cover plate portion and a second cover plate portion surrounding the first cover plate portion, forming a receiving cavity for communicating with a medium to be measured on one side of the first cover plate portion, forming a connecting through hole on the second cover plate portion, and forming an electrode layer on a side of the first cover plate portion close to the receiving cavity, so as to form a first assembly;

[0032] Providing a substrate, and forming a sensing film on one side of the substrate;

[0033] The first assembly is arranged on a side of the sensing film away from the substrate, and the accommodation cavity is located between the first cover plate portion and the sensing film;

[0034] The substrate is etched to form a cavity exposing the sensing film, and a connecting wire is formed in the connecting through hole to connect the sensing film and the electrode layer.

[0035] The technical solution provided by the present disclosure can achieve the following beneficial effects:

[0036] The present disclosure provides a micro differential pressure sensor, which includes a sensing film, a substrate and a cover electrode. The cover electrode may include a cover layer and an electrode layer. Therefore, the present disclosure uses the cover layer to form the cover electrode, and can directly form a receiving cavity on the cover layer by etching. Compared with the prior art, it is no longer necessary to form the cover electrode by depositing a film layer, thereby simplifying the manufacturing steps of the cover electrode and reducing the difficulty of manufacturing the cover electrode, thereby achieving large-scale production.

[0037] At the same time, the accuracy of etching the accommodating cavity directly on the cover layer is higher than the accuracy of etching the accommodating cavity on the deposited film layer. Therefore, using the cover layer to form the cover electrode can also improve the manufacturing accuracy of the micro-differential pressure sensor and improve the performance of the micro-differential pressure sensor.

[0038] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0040] Figure 1 A schematic structural diagram of a micro differential pressure sensor from a first perspective according to an exemplary embodiment of the present disclosure is shown;

[0041] Figure 2 A schematic structural diagram of a micro differential pressure sensor from a first perspective is shown according to another exemplary embodiment of the present disclosure;

[0042] Figure 3 A structural schematic diagram of a micro differential pressure sensor from a second viewing angle according to an exemplary embodiment of the present disclosure is shown;

[0043] Figure 4 A schematic cross-sectional structure diagram of a micro differential pressure sensor according to an exemplary embodiment of the present disclosure is shown;

[0044] Figure 5 A schematic cross-sectional structure diagram of a micro differential pressure sensor in a first state according to another exemplary embodiment of the present disclosure is shown;

[0045] Figure 6 A schematic cross-sectional structure diagram of a micro differential pressure sensor in a second state according to another exemplary embodiment of the present disclosure is shown;

[0046] Figure 7 A schematic flow chart of a method for manufacturing a micro differential pressure sensor according to an exemplary embodiment of the present disclosure is shown;

[0047] Figures 8 to 21 A schematic diagram of the structure of the process of a method for manufacturing a micro differential pressure sensor according to an exemplary embodiment of the present disclosure is shown.

[0048] Description of reference numerals:

[0049] 1. Sensing film; 2. Substrate; 21. Cavity; 3. Cover electrode; 31. Cover layer; 311. First cover portion; 3111. Central area; 3112. Edge area; 312. Second cover portion; 313. Accommodating cavity; 314. Connecting through hole; 3141. First connecting through hole; 3142. Second connecting through hole; 315. Connecting blind hole; 32. Electrical connecting wire; 321. First connecting wire; 3211. First main body; 3212. First extension; 322. Second connecting wire; 3221. Second main body; 3222. Second extension; 33. Electrode layer; 34. Air vent; 35. Protective layer; 36. Insulating layer; 37. Solder ball; 371. First solder ball; 372. Second solder ball; 38. Barrier layer; 381. Via hole;

[0050] X, first direction; Y, second direction. DETAILED DESCRIPTION

[0051] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0052] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0053] The terms "a", "an", "the", and "said" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusion and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first" and "second", etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0054] The present disclosure first provides a micro differential pressure sensor, which can be applied to electronic cigarettes, air conditioners, clean rooms, industrial equipment, medical equipment and other fields. It can be used to detect the pressure difference change in the gas or liquid to be measured medium, and can also be used to detect the pressure or flow rate of the medium to be measured.

[0055] like Figures 1 to 21 As shown, the micro differential pressure sensor provided by the present disclosure may include: a sensing film 1, a substrate 2 and a cover electrode 3. The substrate 2 may be located on one side of the sensing film 1, and the substrate 2 may have a cavity 21, and the cavity 21 may expose the sensing film 1, so that the side of the sensing film 1 close to the substrate 2 may contact the external environment.

[0056] The cover plate electrode 3 may be arranged on a side of the sensing film 1 away from the substrate 2. The cover plate electrode 3 may include: a cover plate layer 31 and an electrode layer 33. The cover plate layer 31 may include a first cover plate portion 311 and a second cover plate portion 312 surrounding the first cover plate portion 311. The electrode layer 33 may be arranged on a side of the first cover plate portion 311 close to the sensing film 1. At least the electrode layer 33, the sensing film 1 and the second cover plate portion 312 form a receiving cavity. The sensing film 1 may be configured to form a capacitor with the electrode layer 33.

[0057] Since the side of the sensing film 1 close to the substrate 2 is in contact with the external environment, the pressure on the side of the sensing film 1 close to the substrate 2 is constant. When the pressure of the medium to be measured in the accommodating cavity 313 changes, the pressure on the side of the sensing film 1 close to the accommodating cavity 313 will change. At this time, the pressure on the side of the sensing film 1 close to the substrate 2 and the side close to the accommodating cavity 313 will be different, causing the sensing film 1 to deform, so that the distance between the sensing film 1 and the electrode layer 33 changes, thereby causing the capacitance value between the sensing film 1 and the electrode layer 33 to change, so that the pressure or flow rate of the medium to be measured can be detected by detecting the change in the capacitance value.

[0058] The micro-differential pressure sensor provided by the present invention utilizes a cover layer 31 to form a cover electrode 3, and can directly form a receiving cavity 313 on the cover layer 31 by etching. Compared with the prior art, it is no longer necessary to form the cover electrode 3 by depositing a film layer, thereby simplifying the manufacturing steps of the cover electrode 3 and reducing the difficulty of manufacturing the cover electrode 3, thereby realizing large-scale production.

[0059] At the same time, the accuracy of directly etching the accommodating cavity 313 on the cover layer 31 is higher than the accuracy of etching the accommodating cavity 313 on the deposited film layer. Therefore, using the cover layer 31 to form the cover electrode 3 can also improve the manufacturing accuracy of the micro-differential pressure sensor and improve the performance of the micro-differential pressure sensor.

[0060] In one embodiment, the material of the substrate 2 may be silicon, the material of the sensing film 1 may be polysilicon, and the material of the cover layer 31 may be glass, that is, the material of the first cover portion 311 and the second cover portion 312 may both be glass, but is not limited thereto.

[0061] In one embodiment, the thickness of the sensing film 1 can be 300nm to 1000nm, for example: 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750μm, 800nm, 850nm, 900nm, 950nm, 1000nm, etc. Such a configuration can avoid the problem of the sensing film 1 being easily damaged during the deformation process due to the thickness being too small, and can improve the service life of the micro differential pressure sensor. At the same time, it can also avoid the problem of the sensing film 1 being too difficult to deform due to the thickness being too large, and can also ensure the sensitivity of the micro differential pressure sensor.

[0062] like Figure 3 As shown, the projection of the substrate 2 in the first direction X may be in a rectangular shape, and the first direction X may be the direction in which the first cover portion 311 points to the sensing film 1. However, the projection of the substrate 2 in the first direction X may also be in a circular shape, a triangular shape, etc. The projection of the first cover portion 311 in the first direction X may be in a rectangular shape, a circular shape, or other shapes, and the shape of the second cover portion 312 may be in a rectangular ring, a circular ring, or other ring shapes.

[0063] In one embodiment, Figure 3 As shown, the shape of the cavity 21 in the first direction X can be circular, rectangular, etc. When the shape of the cavity 21 in the first direction X is circular, its diameter can range from 50 μm to 1000 μm, for example: 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 100 μm, etc. When the shape of the cavity 21 in the first direction X is rectangular, its side length can range from 50 μm to 1000 μm, for example: 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 100 μm, etc.

[0064] In one embodiment, the thickness of the cover layer 31 may be 0.1 mm to 0.7 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, etc. In this way, the problem of the entire micro-differential pressure sensor being too thick due to the cover layer 31 being too thick can be avoided, and the problem of the entire cover electrode 3 having poor structural strength due to the cover layer 31 being too thin can also be avoided.

[0065] In one embodiment, the thickness of the electrode layer 33 may be 100 nm to 1000 nm, for example, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc. This configuration can avoid the problem of the electrode layer 33 occupying too much space in the accommodating cavity 313 due to its excessive thickness, and can also leave enough deformation space for the sensing film 1 to avoid the sensing film 1 from contacting the electrode layer 33.

[0066] The cover plate electrode 3 may further include an electrical connection line 32 . The second cover plate portion 312 may be provided with a connection through hole 314 . The electrical connection line 32 may be electrically connected to the sensing film 1 and the electrode layer 33 through the connection through hole 314 .

[0067] The present disclosure can directly form the connecting through hole 314 on the second cover plate portion 312 by etching, thereby further simplifying the manufacturing steps of the cover plate electrode 3 and further reducing the manufacturing difficulty of the cover plate electrode 3, thereby realizing large-scale production.

[0068] At the same time, the accuracy of etching the connecting through hole 314 directly on the second cover plate portion 312 is higher than the accuracy of etching the connecting through hole 314 on the deposited film layer. Therefore, such a setting can further improve the manufacturing accuracy of the micro-differential pressure sensor and further improve the performance of the micro-differential pressure sensor.

[0069] The diameter of the connecting through hole 314 may be 15 μm to 70 μm, for example, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, etc. The depth of the connecting through hole 314 may be 100 μm to 400 μm, for example, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, etc.

[0070] like Figures 1 to 6 As shown, the cover electrode 3 may further include: a vent hole 34, which may penetrate the first cover portion 311 and the electrode layer 33 along the first direction X, and the vent hole 34 may be connected to the accommodating cavity 313, so as to connect the accommodating cavity 313 with the medium to be measured.

[0071] In one embodiment, there may be a plurality of air holes 34, and the plurality of air holes 34 may be arranged in an array. Such an arrangement may facilitate the medium to be tested to enter the accommodating chamber 313 through the air holes 34. The spacing between any two adjacent air holes 34 may be the same to ensure that the pressure of the medium to be tested is the same when entering the accommodating chamber 313 through the plurality of air holes 34, so as to avoid the problem of large detection errors caused by excessive pressure in some areas or too low pressure in some areas.

[0072] The shape of the air holes 34 in the first direction X may be circular, but is not limited thereto. The shape of the air holes 34 in the first direction X may also be rectangular, triangular, etc., which may be selected and set according to actual conditions.

[0073] The air holes 34 can be formed directly on the cover layer 31 by etching. Compared with the prior art, it is no longer necessary to form the air holes 34 by using a deposited film layer or etching a multi-layer film layer, thereby further simplifying the manufacturing steps of the cover electrode 3 and further reducing the manufacturing difficulty of the cover electrode 3. At the same time, the accuracy of etching the air holes 34 directly on the cover layer 31 is higher than the accuracy of etching the air holes 34 on the deposited film layer, thereby further improving the manufacturing accuracy of the micro-differential pressure sensor and further improving the performance of the micro-differential pressure sensor. In addition, the degree of freedom of directly etching the air holes 34 on the cover layer 31 is relatively high, and the number, formation position and distribution of the air holes 34 formed can be flexibly selected and set, thereby improving the design flexibility of the micro-differential pressure sensor.

[0074] In one embodiment of the present disclosure, the electrical connection line 32 may include: a first connection line 321 and a second connection line 322. The connection through hole 314 may include: a first connection through hole 3141 and a second connection through hole 3142; at least part of the first connection line 321 may be disposed in the first connection through hole 3141 and electrically connected to the sensing film 1 to conduct the electrical signal emitted by the sensing film 1; at least part of the second connection line 322 may be disposed in the second connection through hole 3142 and electrically connected to the electrode layer 33 to conduct the electrical signal emitted by the electrode layer 33.

[0075] It should be noted that in Figure 1 and Figure 2 Four connecting through holes 314 are provided on the second cover plate portion 312 , wherein two connecting through holes 314 with reference numerals are the first connecting through hole 3141 and the second connecting through hole 3142 , and the remaining two connecting through holes 314 are used for connecting components such as chips in subsequent processes or for grounding.

[0076] In one embodiment, the first connecting line 321 may include: a first main body portion 3211 and a first extension portion 3212. The first main body portion 3211 may be disposed in the first connecting through hole 3141 and electrically connected to the sensing film 1. The first extension portion 3212 may be located at least on a side of the second cover portion 312 away from the sensing film 1 and connected to the first main body portion 3211. With such a configuration, the first connecting line 321 may be conveniently connected to an external circuit through the first extension portion 3212, thereby facilitating the transmission of an electrical signal emitted by the sensing film 1 to the external circuit.

[0077] The second connection line 322 may include: a second body portion 3221 and a second extension portion 3222, the second body portion 3221 is disposed in the second connection through hole 3142 and is electrically connected to the electrode layer 33, and the second extension portion 3222 may be located at least on a side of the second cover portion 312 away from the sensing film 1 and connected to the second body portion 3221. With such a configuration, the second connection line 322 may be conveniently connected to an external circuit through the second extension portion 3222, thereby facilitating the transmission of an electrical signal emitted by the electrode layer 33 to the external circuit.

[0078] In one embodiment, the first extension portion 3212 and / or the second extension portion 3222 may further extend to a side of the first cover portion 311 away from the sensing film.

[0079] The material of the first connection line 321 and the second connection line 322 can be copper, but is not limited thereto. The material of the first connection line 321 and the second connection line 322 can also be other materials with conductive properties. The present disclosure does not limit this and can be selected and set according to actual conditions.

[0080] In one embodiment, the cover electrode 3 may further include a solder ball 37, which may be connected to the electrical connection line 32 for welding with an external circuit to connect the electrical connection line 32 to the external circuit. For example, the external circuit may include a circuit board, and the solder ball 37 may be welded on the circuit board to connect the electrical connection line 32 to the external circuit.

[0081] The solder ball 37 may include: a first solder ball 371 and a second solder ball 372. The first solder ball 371 may be disposed on a side of the first extension portion 3212 away from the second cover portion 312 to connect the first connection line 321 to an external circuit. The second solder ball 372 may be disposed on a side of the second extension portion 3222 away from the second cover portion 312 to connect the second connection line 322 to an external circuit.

[0082] In one embodiment of the present disclosure, Figure 1 , Figure 2 , Figure 5 and Figure 6As shown, the first cover plate portion 311 may have a central area 3111 and an edge area 3112, the edge area 3112 may be arranged around the central area 3111, and the distance between the portion of the first cover plate portion 311 located in the central area 3111 and the sensing film 1 may be greater than the distance between the portion of the first cover plate portion 311 located in the edge area 3112 and the sensing film 1. When the sensing film 1 is deformed in the direction close to the first cover plate portion 311, the deformation amount of the central position of the sensing film 1 is greater than the deformation amount of the edge position of the sensing film 1. Therefore, through the above arrangement, a larger deformation space can be reserved for the central position of the sensing film 1, which can effectively prevent the central position of the sensing film 1 from contacting the electrode layer 33 when deforming.

[0083] In one embodiment, the distance between the portion of the first cover plate portion 311 located in the edge region 3112 and the sensing film 1 can be reduced along the second direction Y. The second direction Y can be a direction from the central region 3111 to the edge region 3112. Since the sensing film 1 is deformed in the direction close to the first cover plate portion 311, the deformation of the sensing film 1 will gradually decrease along the second direction Y. Therefore, through the above arrangement, the distance between the portion of the first cover plate portion 311 located in the edge region 3112 and the sensing film 1 can match the deformation of the sensing film 1, thereby leaving enough deformation space for the edge position of the sensing film 1, and effectively preventing the sensing film 1 from contacting the electrode layer 33 when deforming.

[0084] At the same time, since the first cover portion 311 provided in the present disclosure is a part of the cover layer 31, and the cover layer 31 is easier to process than the deposited multi-layer film layer structure, the present disclosure utilizes the cover layer 31 to achieve the structure of the first cover portion 311 mentioned in this embodiment, while the prior art cannot achieve the above-mentioned structure of the first cover portion 311 using a multi-layer film layer structure.

[0085] In one embodiment of the present disclosure, Figures 1 to 6 As shown, the cover plate electrode 3 may further include: a protective layer 35. The protective layer 35 may be disposed on a side of the cover plate layer 31 away from the sensing film 1, and may at least cover the vent hole 34. In this way, the protective layer 35 may be used to block oil stains in the external environment, so as to prevent oil stains, water vapor and other impurities in the external environment from entering the accommodating cavity 313 through the vent hole 34 and causing damage to the micro differential pressure sensor.

[0086] In one embodiment, the protective layer 35 may be a mesh structure, and such a configuration can ensure that the medium to be measured can pass through the protective layer 35 and enter the accommodating chamber 313. The present disclosure does not impose any specific restrictions on the mesh size of the protective layer 35. When the mesh of the protective layer 35 is larger, the speed at which the medium to be measured enters the accommodating chamber 313 and the pressure relief speed of the accommodating chamber 313 can be increased, thereby improving the sensitivity of the micro-differential pressure sensor. However, when the mesh of the protective layer 35 is larger, its protective effect against impurities such as oil, water vapor, etc. will be weakened. When the mesh of the protective layer 35 is smaller, the speed at which the medium to be measured enters the accommodating chamber 313 and the pressure relief speed of the accommodating chamber 313 can be reduced, thereby reducing the sensitivity of the micro-differential pressure sensor. When the mesh of the protective layer 35 is smaller, its protective effect against impurities such as oil, water vapor, etc. can be greatly improved.

[0087] It should be noted that Figure 1 and Figure 2 The specific structure of the protective layer 35 is not shown, only the position of the protective layer 35 is shown.

[0088] The material of the protective layer 35 can be polytetrafluoroethylene, polyethylene film, perfluoroalkyl, polyfluoroalkyl substances, etc. In one embodiment of the present disclosure, the micro differential pressure sensor may further include: an insulating layer 36. The insulating layer 36 may be located between the substrate 2 and the cover electrode 3, and may be arranged around the sensing film 1. By providing the insulating layer 36, the leakage of electrical signals of the sensing film 1 can be avoided, and the detection accuracy of the micro differential pressure sensor can be improved. The material of the insulating layer 36 may be high-resistance silicon, silicon nitride, silicon dioxide, etc.

[0089] In one embodiment of the present disclosure, the micro differential pressure sensor may further include: a barrier layer 38. The barrier layer 38 may be disposed between the sensing film 1 and the substrate 2, and the barrier layer 38 may have a via 381, and the projection of the via 381 in the first direction X may at least overlap with the projection of the back cavity in the first direction X, so as to expose the sensing film 1. The present disclosure can avoid damaging the sensing film 1 in the process of etching the substrate 2 to form the back cavity by providing the barrier layer 38, thereby improving the product yield.

[0090] The thickness of the barrier layer 38 may be 20 nm to 50 nm, for example, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc. This arrangement can avoid increasing the thickness of the entire micro differential pressure sensor due to the barrier layer 38 being too thick, and can also avoid failing to provide good protection for the sensing film 1 due to the barrier layer 38 being too thin.

[0091] The material of the barrier layer 38 may be silicon dioxide, but is not limited thereto. The material of the barrier layer 38 may also be other materials and may be configured according to actual conditions, all of which are within the scope of protection of the present disclosure.

[0092] Another aspect of the present disclosure provides a method for manufacturing a micro differential pressure sensor. The method for manufacturing a micro differential pressure sensor can be used to manufacture the micro differential pressure sensor described above.

[0093] like Figures 7 to 21 As shown, the method for manufacturing the micro differential pressure sensor provided by the present disclosure may include:

[0094] Step S10 , providing a cover layer 31 , the cover layer 31 comprising a first cover portion 311 and a second cover portion 312 surrounding the first cover portion 311 , forming an electrode layer 33 on one side of the first cover portion 311 to form a cover electrode 3 .

[0095] Step S20 , providing a substrate 2 , and forming a sensing film 1 on one side of the substrate 2 .

[0096] Step S30 , disposing the cover electrode 3 on the side of the sensing film 1 away from the substrate 2 , wherein at least the electrode layer 33 , the sensing film 1 and the second cover portion 312 form a receiving cavity 313 .

[0097] Step S40 , etching the substrate 2 to form a cavity 21 exposing the sensing film 1 .

[0098] The sensing film 1 may be configured to form a capacitor with the electrode layer 33 .

[0099] The manufacturing method of the micro-differential pressure sensor provided in the present disclosure utilizes the cover layer 31 to form the cover electrode 3, and can directly form the accommodating cavity 313 on the cover layer 31 by etching. Compared with the prior art, it is no longer necessary to form the cover electrode 3 by depositing a film layer, thereby simplifying the manufacturing steps of the cover electrode 3 and reducing the difficulty of manufacturing the cover electrode 3, thereby realizing large-scale production.

[0100] At the same time, the accuracy of directly etching the accommodating cavity 313 on the cover layer 31 is higher than the accuracy of etching the accommodating cavity 313 on the deposited film layer. Therefore, using the cover layer 31 to form the cover electrode 3 can also improve the manufacturing accuracy of the micro-differential pressure sensor and improve the performance of the micro-differential pressure sensor.

[0101] It should be noted that since the specific structure and beneficial effects of the micro differential pressure sensor have been described in detail in the previous topic of the present disclosure, the specific structure and beneficial effects of the micro differential pressure sensor will not be repeated in this topic, and the above description can be referred to, which is also within the scope of protection of the present disclosure.

[0102] The above steps are described in detail below:

[0103] In step S10, Figures 8 to 12As shown, a cover layer 31 may be provided, and the thickness of the cover layer 31 may be 0.1 mm to 0.7 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, etc. The material of the cover layer 31 may be glass, but is not limited thereto.

[0104] The cover layer 31 may be cleaned with a cleaning liquid to remove particles and impurities on the surface of the cover layer 31 , so as to prevent particles and impurities on the surface of the cover layer 31 from entering the accommodating cavity 313 and causing damage to the entire micro-differential pressure sensor.

[0105] The cover layer 31 may be modified so that the material of the area corresponding to the accommodating cavity 313 is easier to etch. The cover layer 31 may be etched to form the accommodating cavity 313. When the cover electrode 3 also includes a connecting through hole 314, the material of the area corresponding to the connecting through hole 314 may also be modified, and the cover layer 31 may be etched to form the connecting through hole 314. When the cover electrode 3 also includes a vent 34, the material of the area corresponding to the vent 34 may also be modified, and the cover layer 31 may be etched to form the vent 34. For example: the cover layer 31 may be modified using a laser modification process, and the connecting through hole 314, the accommodating cavity 313, and the vent 34 may be etched using wet etching, but is not limited thereto.

[0106] In one embodiment, the material of the area corresponding to the connecting through hole 314 and the accommodating cavity 313 and the material of the area corresponding to the vent hole 34 can be modified by a single modification process, and the connecting through hole 314, the accommodating cavity 313 and the vent hole 34 can be simultaneously formed by a single etching. In this way, the manufacturing steps of the cover electrode 3 can be reduced.

[0107] When etching to form the connecting through hole 314, the cover layer 31 may be etched first to form the connecting blind hole 315, and then the cover layer 31 may be thinned using a thinning process to remove a portion of the cover layer 31 at the bottom of the connecting blind hole 315, thereby converting the connecting blind hole 315 into a connecting through hole 314. For example, the thinning process described herein may be a chemical mechanical polishing process, but is not limited thereto. The thickness of the thinned cover layer 31 may be 0.05 mm to 0.5 mm, for example: 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0108] In one embodiment, when the connection through-hole 314 includes the first connection through-hole 3141 and the second connection through-hole 3142 , the first connection through-hole 3141 and the second connection through-hole 3142 may be formed simultaneously in the above manner.

[0109] In one embodiment, when it is necessary to make the distance between the portion of the first cover portion 311 located in the central area 3111 and the sensing film 1 greater than the distance between the portion of the first cover portion 311 located in the edge area 3112 and the sensing film 1, the first cover portion 311 can be modified through a modification process so that the unmodified material can present the above-mentioned structural shape, thereby forming the above-mentioned structural shape after etching.

[0110] Similarly, when it is necessary to reduce the distance between the portion of the first cover portion 311 located in the edge area 3112 and the sensing film 1 along the second direction Y, the first cover portion 311 can also be modified through a modification process so that the unmodified material can present the structural shape, thereby forming this structural shape after etching.

[0111] Further, a material for forming an electrode layer 33 may be deposited on one side of the first cover plate portion 311 close to the accommodating cavity 313 to form the electrode layer 33. The material for forming the electrode layer 33 may be aluminum, but is not limited thereto, and the material for forming the electrode layer 33 may also be doped polysilicon, copper, gold, and the like. The electrode layer 33 may be deposited by physical vapor deposition, but is not limited thereto.

[0112] In step S20, Figures 13 to 15 As shown, a substrate 2 may be provided, and a barrier layer 38 may be formed on one side surface of the substrate 2. Specifically, the substrate 2 may be subjected to a thermal oxidation process to form the barrier layer 38 on the surface of the substrate 2, but is not limited thereto, and the barrier layer 38 may also be formed using other processes.

[0113] The material for forming the sensing film 1 may be deposited on the surface of the barrier layer 38 and patterned to form the sensing film 1. The material for forming the sensing film 1 may be doped polysilicon, but is not limited thereto. Furthermore, the sensing film 1 may be deposited by chemical vapor deposition, but is not limited thereto.

[0114] A material for forming the insulating layer 36 may be deposited around the sensing film 1 to form the insulating layer 36 disposed around the sensing film 1. When forming the insulating layer 36, a chemical vapor deposition method may be used, but is not limited thereto.

[0115] In step S30, Fig.16 As shown, the first assembly can be arranged on the side of the sensing film 1 away from the substrate 2, and the accommodating cavity 313 is located between the first cover portion 311 and the sensing film 1. Specifically, the first assembly can be arranged on the side of the sensing film 1 away from the substrate 2 by using anodic bonding.

[0116] In step S40, Figures 17 to 21As shown, the substrate 2 may be etched to form a cavity 21 exposing the sensing film 1. Specifically, the substrate 2 may be etched by a deep reactive ion etching process to form the cavity 21 on a side of the substrate 2 facing away from the sensing film 1. The barrier layer 38 may be etched by a wet etching process to form a via 381, and the projection of the via 381 in the first direction X at least overlaps with the projection of the cavity 21 in the first direction X, thereby exposing the sensing film 1.

[0117] A connection line may be formed in the connection through hole 314 to connect the sensing film 1 and the electrode layer 33. Specifically, the connection line may be formed by depositing a material for forming the connection line on the sidewall of the connection through hole 314. For example, the connection line may be formed by depositing a seed layer by magnetron sputtering and a chemical plating process, but is not limited thereto.

[0118] In one embodiment, when the connecting wire includes a first connecting wire and a second connecting wire, the first connecting wire and the second connecting wire can be formed simultaneously by using the above method.

[0119] When the first connecting wire includes the first extension part 3212 and the second connecting wire includes the second extension part 3222, the material for forming the first extension part 3212 and the second extension part 3222 can be deposited at least on one side of the second cover plate 312 away from the sensing film 1 in the above manner to form the first extension part 3212 and the second extension part 3222. In step S40, a protective layer 35 can also be formed on one side of the cover plate layer 31 away from the sensing film 1, and the protective layer 35 at least covers the vent hole 34.

[0120] A solder ball 37 may be provided on the electrical connection line 32 to connect the electrical connection line 32 to an external circuit. When the connection line includes a first connection line and a second connection line, a first solder ball 371 may be provided on the first extension portion 3212 of the first connection line, and a second solder ball 372 may be provided on the second extension portion 3222 of the second connection line.

[0121] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The description and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A micro differential pressure sensor, characterized in that: include: Sensing membrane; A substrate is located on one side of the sensing film, and the substrate has a cavity, wherein the cavity exposes the sensing film; A cover plate electrode is arranged on a side of the sensing film away from the substrate, and the cover plate electrode comprises: a cover plate layer and an electrode layer; the cover plate layer comprises a first cover plate portion and a second cover plate portion surrounding the first cover plate portion, the electrode layer is arranged on a side of the first cover plate portion close to the sensing film, and at least the electrode layer, the sensing film and the second cover plate portion form a receiving cavity; Wherein, the sensing film is configured to form a capacitor with the electrode layer.

2. The micro differential pressure sensor according to claim 1, characterized in that: The first cover plate portion and the second cover plate portion are both made of glass.

3. The micro differential pressure sensor according to claim 1, characterized in that: The cover electrode further comprises: The second cover plate portion is provided with an electrical connection line, and the electrical connection line is electrically connected to the sensing film and the electrode layer through the connection through hole.

4. The micro differential pressure sensor according to claim 1, characterized in that: The cover electrode further comprises: A vent hole, the vent hole penetrates the first cover plate portion and the electrode layer along a first direction and is connected to the accommodating cavity, so as to connect the accommodating cavity with the medium to be measured; Wherein, the first direction is the direction in which the first cover portion points to the sensing film.

5. The micro differential pressure sensor according to claim 4, characterized in that: There are a plurality of the ventilation holes, and the plurality of the ventilation holes are arranged in an array.

6. The micro differential pressure sensor according to claim 3, characterized in that: The electrical connection line includes a first connection line and a second connection line, and the connection through hole includes: a first connecting through hole, wherein at least a portion of the first connecting wire is disposed in the first connecting through hole and is electrically connected to the sensing film; A second connecting through hole, wherein at least a portion of the second connecting line is disposed in the second connecting through hole and is electrically connected to the electrode layer.

7. The micro differential pressure sensor according to claim 6, characterized in that: The first connecting line comprises: a first main body and a first extension, wherein the first main body is disposed in the first connecting through hole and is electrically connected to the sensing film, and the first extension is at least located on a side of the second cover plate away from the sensing film and is connected to the first main body; The second connecting line includes: a second main body and a second extension part, the second main body is arranged in the second connecting through hole and electrically connected to the electrode layer, and the second extension part is at least located on a side of the second cover part away from the sensing film and connected to the second main body.

8. The micro differential pressure sensor according to any one of claims 1 to 7, characterized in that: The first cover plate portion has a central area and an edge area, the edge area is arranged around the central area, and the distance between the portion of the first cover plate portion located in the central area and the sensing film is greater than the distance between the portion of the first cover plate portion located in the edge area and the sensing film.

9. The micro differential pressure sensor according to claim 8, characterized in that: The distance between the first cover portion located in the edge area and the sensing film decreases along the second direction; The second direction is the direction from the central area to the edge area.

10. The micro differential pressure sensor according to any one of claims 4 or 5, characterized in that: The cover electrode further comprises: The protective layer is arranged on a side of the cover layer away from the sensing film and at least covers the air holes.

11. The micro differential pressure sensor according to any one of claims 1 to 7, characterized in that: The micro differential pressure sensor also includes: The insulating layer is located between the substrate and the cover electrode and is arranged around the sensing film.

12. A method for manufacturing a micro differential pressure sensor, characterized in that: include: Providing a cover plate layer, the cover plate layer comprising a first cover plate portion and a second cover plate portion surrounding the first cover plate portion, and forming an electrode layer on one side of the first cover plate portion to form a cover plate electrode; Providing a substrate, and forming a sensing film on one side of the substrate; The cover plate electrode is arranged on a side of the sensing film away from the substrate, and at least the electrode layer, the sensing film and the second cover plate portion form a receiving cavity; Etching the substrate to form a cavity exposing the sensing film; Wherein, the sensing film is configured to form a capacitor with the electrode layer.

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