Sensor, electronic device, and method of manufacturing

Abstract

The application provides a sensor, an electronic device and a preparation method. The sensor comprises: a first substrate, a first electrode layer, a medium layer, a second electrode layer and a second substrate which are stacked, and the second substrate is provided with a stepped hole; a pressure sensing layer is embedded in the stepped hole, and a thinning portion for reducing the local thickness of the pressure sensing layer is provided on the side of the pressure sensing layer close to the first substrate; one side of the second electrode layer is protruded to form a protruding portion in the direction away from the first substrate, and the protruding portion is attached to the inner surface of the thinning portion; the other side of the second electrode layer is recessed to form a recessed portion in the direction away from the first substrate, and the recessed portion corresponds to the protruding portion. The stepped hole of the second substrate can form the pressure sensing layer inside, and the preparation difficulty of the pressure sensing layer is reduced. The thinning portion is provided on the side of the pressure sensing layer close to the first substrate, so that the thickness of the pressure sensing layer is reduced, the deformation effect is enhanced, and the sensitivity to external pressure and the measurement accuracy of the sensor are improved.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a sensor, electronic device, and method of fabrication. Background Technology

[0002] Capacitive pressure sensors are a common type of thin-film sensor. With the rapid development of integrated circuit technology and the increasing integration of electronic devices, these sensors can be integrated into silicon substrates such as glass for application. When fabricating the pressure-sensing layer of the sensor, an etching process can be used to form an integrated sensing film within the silicon substrate. However, because the pressure-sensing layer is integrally formed within the silicon substrate, its fabrication process is challenging, and the fabrication precision is difficult to control precisely, thus affecting the sensor's ability to sense external pressure. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a sensor, electronic device and manufacturing method to solve some or all of the technical problems mentioned above.

[0004] For the purposes described above, this application provides a sensor, comprising:

[0005] A first substrate, a first electrode layer, a dielectric layer, a second electrode layer, and a second substrate are stacked, wherein the second substrate has stepped holes; and

[0006] A pressure-sensitive layer is embedded in the stepped hole, and a thinning portion is recessed on the side of the pressure-sensitive layer near the first substrate to reduce the local thickness of the pressure-sensitive layer.

[0007] One side of the second electrode layer protrudes in a direction away from the first substrate to form a protrusion, and the protrusion is in contact with the inner surface of the thinned portion; the other side of the second electrode layer is recessed in a direction away from the first substrate to form a recess, and the recess corresponds to the protrusion.

[0008] Based on the same inventive concept, a second aspect of this application also provides an electronic device including the sensor described in the first aspect.

[0009] Based on the same inventive concept, a third aspect of this application also provides a method for manufacturing a sensor, comprising:

[0010] A first substrate is provided, on one side of the first substrate a first electrode layer and a dielectric layer are sequentially formed, and a first through-hole is formed in the dielectric layer;

[0011] A second substrate is provided, a first receiving portion is formed on a first side of the second substrate, and a boss structure protruding toward the first side is formed in the first receiving portion;

[0012] A first conductive layer and a pressure-sensitive layer are sequentially formed in the first accommodating portion, such that the first conductive layer covers the boss structure and the pressure-sensitive layer covers the first conductive layer.

[0013] A second receiving portion is formed on the second side of the second substrate to communicate with the first receiving portion. The boss structure is etched away to form a thinning portion on the surface of the pressure-sensitive layer away from the first side, so that the first conductive layer is located in the thinning portion and relatively exposed.

[0014] A second conductive layer is formed on the second side of the second substrate, so that the second conductive layer is integrally connected with the edge of the first conductive layer to form a second electrode layer; wherein, corresponding protrusions and recesses are formed on opposite sides of the second electrode layer, and the surfaces of the protrusions are respectively attached to the second receiving portion and the thinning portion;

[0015] The dielectric layer is bonded to the second side of the second substrate from the side away from the first substrate, so that the recess corresponds to the first through hole.

[0016] As can be seen from the above, the sensor, electronic device, and fabrication method provided in this application allow the sensor to form a pressure-sensitive layer within a stepped hole in the second substrate, reducing the difficulty of forming the pressure-sensitive layer. Furthermore, a thinning portion is provided on the side of the pressure-sensitive layer near the first substrate, and the second electrode layer protrudes in a direction away from the first substrate to form a protrusion and adheres to the thinning portion. This can improve the fabrication precision of the pressure-sensitive layer, increase the distance between the second electrode layer and the first electrode layer located within the thinning portion, and improve the sensitivity and accuracy of the sensor in measuring external pressure, thereby improving the overall performance of the sensor. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the first type of sensor in the embodiments of this application;

[0019] Figure 2 This is a top view of the first type of sensor in the embodiments of this application;

[0020] Figure 3 This is a schematic diagram of the second type of sensor in the embodiments of this application;

[0021] Figure 4This is a schematic diagram of the third type of sensor in the embodiments of this application;

[0022] Figure 5 This is a schematic diagram of the fourth type of sensor in the embodiments of this application;

[0023] Figure 6 This is a schematic diagram of the fifth type of sensor in the embodiments of this application;

[0024] Figure 7 This is a schematic diagram of the sixth type of sensor in the embodiments of this application;

[0025] Figure 8 This is a schematic diagram of the seventh type of sensor in the embodiments of this application;

[0026] Figure 9 This is a schematic diagram of the eighth type of sensor in the embodiments of this application;

[0027] Figure 10 This is a schematic diagram of the ninth type of sensor in the embodiments of this application;

[0028] Figures 11A-11H This is a flowchart illustrating the fabrication process of the sensor in this application embodiment;

[0029] Figure 12 This is a flowchart of the sensor fabrication method in an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. First substrate; 101. Second through-hole;

[0032] 2. First electrode layer;

[0033] 3. Dielectric layer; 301. First through-hole;

[0034] 4. Second electrode layer; 410. Protrusion; 420. Recess;

[0035] 5. Second substrate; 501. Hollowed-out structure; 510. Stepped hole; 511. First receiving portion; 512. Second receiving portion;

[0036] 6. Pressure-sensitive layer; 601. Thinned section; 602. Fourth through hole;

[0037] 7. Protective layer; 701. Third through hole;

[0038] 801. Via; 802. Contact; 803. Electrical connection;

[0039] 9. Boss structure. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0041] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] In some embodiments, thin-film sensors, such as capacitive pressure sensors, can be integrated into silicon substrates such as glass for application, such as display panels, barometers, and hydraulic presses. Specifically, a capacitive pressure sensor may include an upper substrate and a lower substrate. During sensor fabrication, a monolithic pressure-sensing layer can be fabricated on the upper substrate (blind-glass via) using BGV technology, and a capacitor structure is built on the surface of the pressure-sensing layer. When external pressure is applied to the pressure-sensing layer, it deforms, and the deformation changes the spacing between the two electrode layers in the capacitor structure, thereby changing the capacitance of the capacitor structure to convert the pressure signal into an electrical signal to measure the external pressure data. Simultaneously, the upper and lower substrates can form corresponding vias using TGV technology (through-glass via). The capacitor structure can be electrically connected to the chip through the vias, and the converted electrical signal is sent to the chip, thereby realizing signal transmission between the chip and the capacitor structure.

[0043] When integrating the capacitive pressure sensor described above into a silicon substrate such as glass, a pressure-sensitive layer can be formed on the upper substrate using the following process: For example, for capacitive pressure sensors with high thickness requirements, the first side of the upper substrate can be modified using laser technology, and then the modified area can be further processed using etching to form blind holes. Subsequently, a thinning process is used to thin the second side of the upper substrate opposite to the first side, gradually thinning the bottom of the blind holes to serve as the pressure-sensitive layer. Alternatively, for capacitive pressure sensors with lower thickness requirements, two opposing blind holes can be etched on opposite sides of the upper substrate using etching technology, thereby forming a corresponding pressure-sensitive layer between the two blind holes.

[0044] However, the applicant discovered that, due to the integral molding process of the pressure-sensitive layer and the silicon substrate, limitations imposed by the manufacturing process and the position of the pressure-sensitive layer within the upper substrate make it difficult to form a thin and uniform pressure-sensitive layer within the silicon substrate during sensor fabrication. Furthermore, since the pressure-sensitive layer and the upper substrate are integrally molded, when using silicon substrates such as glass as the upper substrate, minute impurities or defects may exist within it. This results in a relatively poor quality pressure-sensitive layer formed from such an upper substrate. Because the capacitor's electrode layer is tightly bonded to the pressure-sensitive layer, these impurities or defects can cause leakage current within the silicon substrate near the pressure-sensitive layer. This leakage rate increases significantly, especially under high temperature or high pressure conditions, reducing the accuracy and sensitivity of the pressure sensor in measuring external pressure and affecting the overall quality of the product.

[0045] A first aspect of this application provides a sensor, combined with an attached... Figures 1-10 The content shown provides a detailed description of the sensor.

[0046] A sensor includes a first substrate 1, a first electrode layer 2, a dielectric layer 3, a second electrode layer 4, and a second substrate 5 stacked together. The second substrate 5 has a stepped hole 510. It also includes a pressure-sensitive layer 6 embedded in the stepped hole 510. The pressure-sensitive layer 6 has a thinning portion 601 recessed on the side near the first substrate 1 to reduce the local thickness of the pressure-sensitive layer 6. One side of the second electrode layer 4 protrudes in a direction away from the first substrate 1 to form a protrusion 410, and the protrusion 410 is in contact with the inner surface of the thinning portion 601. The other side of the second electrode layer 4 is recessed in a direction away from the first substrate 1 to form a recess 420, and the recess 420 corresponds to the protrusion 410.

[0047] Specifically, such as Figures 1-10As shown, the pressure sensor includes a first substrate 1, a first electrode layer 2, a dielectric layer 3, a second electrode layer 4, and a second substrate 5. The first electrode layer 2, the dielectric layer 3, and the second electrode layer 4 are stacked sequentially between the first substrate 1 and the second substrate 5. The first substrate 1 supports and protects the first electrode layer 2, and the second substrate 5 supports and protects the second electrode layer 4. More specifically, the pressure sensor measures external pressure by changing its capacitance. Therefore, for the sensor, the first electrode layer 2, the dielectric layer 3, and the second electrode layer 4 constitute a capacitor structure, with the first electrode layer 2 and the second electrode layer 4 serving as the two plates of the capacitor. The dielectric layer 3 is located between the first electrode layer 2 and the second electrode layer 4 to isolate and electrically insulate the two electrode layers.

[0048] For example, the first substrate 1 and the second substrate 5 may be formed of a silicon-based material, such as glass, to control production costs.

[0049] For example, the first electrode layer 2 and the second electrode layer 4 can be formed using non-transparent metal materials such as aluminum, copper, titanium, silver, molybdenum, and nickel-chromium alloys, or transparent metal materials such as indium tin oxide. In addition, the first electrode layer 2 and the second electrode layer 4 can be formed by sputtering on the surfaces of the first substrate 1 and the second substrate 5 using PVD (Physical vapor deposition) process, which will not be described in detail here.

[0050] For example, the dielectric layer 3 can be formed of insulating materials such as polyamide or polyimide, which is low in cost and has good insulation performance.

[0051] Specifically, such as Figures 1-10As shown, the pressure sensor provided in this application also includes a pressure-sensing layer 6. The second substrate 5 has a stepped hole 510, and the pressure-sensing layer 6 is embedded in the stepped hole 510 of the second substrate 5, so as to provide a preparation position for the pressure-sensing layer 6 through the stepped hole 510. When preparing the pressure-sensing layer 6, at least a portion of the stepped hole 510 can be formed in the second substrate 5 first, and a first conductive layer can be formed in the stepped hole 510 using a PVD process. This portion of the conductive layer is used as part of the second electrode layer 4. Then, the pressure-sensing layer 6 is formed using a PECVD (Plasma enhanced chemical vapor deposition) process. Subsequently, the surface of the first conductive layer is exposed using an etching process. In this way, a thin and high-quality pressure-sensing layer 6 can be formed in the stepped hole 510. Compared to the integrated pressure-sensing layer 6 in related technologies, the pressure-sensing layer 6 formed in the stepped hole 510 can reduce the manufacturing difficulty and cost. At the same time, materials with excellent deformation ability and low leakage rate can be selected to form the pressure-sensing layer 6 inside the stepped hole 510, which is beneficial to improve the sensing performance of the pressure-sensing layer 6, enhance its measurement accuracy and sensitivity to external pressure, and thus improve the product quality of the sensor.

[0052] Furthermore, such as Figures 1-10 As shown, a thinning portion 601 is recessed on the side of the pressure-sensitive layer 6 near the first substrate 1. By adding the thinning portion 601, the firmness of the pressure-sensitive layer 6 embedded in the stepped hole 510 can be ensured. At the same time, the thickness of the pressure-sensing area of ​​the pressure-sensitive layer 6 can be further reduced, thereby enhancing its deformation capability and improving the sensing effect of external pressure. Furthermore, since the thinning portion 601 is formed simultaneously during the preparation of the stepped hole 510, that is, the thinning portion 601 is formed simultaneously during the formation of the stepped hole 510, not only is the thinning of the pressure-sensitive layer 6 achieved, but the formation process of the thinning portion 601 is also simplified, which helps to reduce production costs and improve the economic efficiency of the product.

[0053] Specifically, the pressure sensor provided in this application mainly changes the spacing between the two plates in the capacitor structure by deforming the pressure-sensing layer 6, thereby changing the voltage and converting the pressure signal into an electrical signal; such as Figure 1 , Figures 3-7 , Figure 9 as well as Figure 10As shown, for the sensor, the first electrode layer 2 and the second electrode layer 4 are equivalent to the two plates of a capacitor structure. The first electrode layer 2 and the second electrode layer 4 are separated by a dielectric layer 3 to create a gap between them. One side of the second electrode layer 4 protrudes away from the first substrate 1 to form a protrusion 410, and the other side is recessed away from the first substrate 1 to form a recess 420, so that part of the second electrode layer 4 is in close contact with the inner surface of the thinned portion 601 of the pressure-sensing layer 6. When the pressure-sensing layer 6 deforms under external pressure, the second electrode layer 4 will also deform synchronously, changing the gap between the first electrode layer 2 and the second electrode layer 4 and changing the voltage difference between them, thereby converting the pressure signal into an electrical signal. This design not only increases the gap between the two plates in the capacitor structure and reduces the electric field strength between the plates, but also effectively reduces the leakage current and the risk of dielectric breakdown, thereby improving the stability and reliability of the sensor.

[0054] In some embodiments, the pressure-sensitive layer 6 is formed of silicon nitride, and the thickness of the pressure-sensitive layer 6 is within the range of 0.02-2 μm.

[0055] Specifically, when the sensor is formed using a silicon substrate such as glass, the pressure-sensitive layer 6 can be made of a different material than the second substrate 5, thereby reducing the leakage rate of the sensor. More specifically, the pressure-sensitive layer 6 can be made of silicon nitride. From a fabrication perspective, when using silicon nitride to fabricate the pressure-sensitive layer 6, it can be formed by PECVD deposition or by coating, both of which reduce the fabrication difficulty of the pressure-sensitive layer 6 and ensure that the formed pressure-sensitive layer 6 has good accuracy. Compared with other silicon-based materials, when using silicon nitride to form the pressure-sensitive layer 6 using the PECVD process, the pressure-sensitive layer 6 can be flexibly adjusted, which is beneficial for obtaining pressure-sensitive layers 6 with different tensile and tensile stresses. In addition, during the material selection process, by selecting silicon nitride materials with different ratios of silicon and nitrogen, pressure-sensitive layers 6 with different mechanical strengths can be obtained. This allows for the flexible fabrication of various pressure-sensitive layers 6 according to actual application requirements, improving the adaptability of the sensor and enriching its diversity.

[0056] More specifically, the thickness of the pressure-sensitive layer 6 is typically controlled within the range of 0.02-2 μm. Setting the thickness of the pressure-sensitive layer 6 above 0.02 μm ensures that it has sufficient mechanical strength, preventing cracking or damage due to the measurement of large external pressures, and also helps to reduce its manufacturing difficulty. Limiting the thickness to below 2 μm ensures that the pressure-sensitive layer 6 has good deformation capacity, thereby ensuring its sensing effect on external pressure. This thickness range takes into account both the mechanical properties of the pressure-sensitive layer 6 and the sensitivity and reliability of the sensor.

[0057] In some embodiments, the stepped hole 510 includes a first receiving portion 511 and a second receiving portion 512; the first receiving portion 511 is formed on a first side of the second substrate 5; the pressure-sensitive layer 6 is embedded in the first receiving portion 511; the second receiving portion 512 is formed on a second side of the second substrate 5 and communicates with the first receiving portion 511; the protrusion 410 penetrates the second receiving portion 512 and is in contact with the inner surface of the second receiving portion 512; wherein, the second side is closer to the first substrate 1 than the first side.

[0058] Specifically, the stepped hole 510 formed in the second substrate 5 not only provides a fabrication location for the pressure-sensitive layer 6, but also increases the spacing between certain parts of the first electrode layer 2 and the second electrode layer 4, thereby improving the sensor's ability to measure external pressure. For example... Figure 1 , Figures 3-7 , Figure 9 as well as Figure 10 As shown, the two opposite sides of the second substrate 5 are the first side and the second side, respectively. The first receiving portion 511 is located on the first side of the second substrate 5 and is used as the preparation position of the pressure-sensitive layer 6 to ensure the firmness of the connection between the pressure-sensitive layer 6 and the second substrate 5. The second receiving portion 512 is opened on the second side of the second substrate 5 and communicates with the first receiving portion 511, thereby increasing the spacing between the first electrode layer 2 and the second electrode layer 4 located in the thinning portion 601.

[0059] More specifically, when the protrusion 410 of the second electrode layer 4 penetrates the second receiving portion 512 and adheres to the inner surface, the connection between the second electrode layer 4 and the second substrate 5 can be strengthened. In this way, when the pressure-sensitive layer 6 deforms, the part of the second electrode layer 4 that is adhered to the thinning portion 601 can deform. Even if the part subjected to external pressure deforms, unnecessary deformation of the part not subjected to external pressure is avoided, thereby improving the sensitivity and accuracy of the pressure sensor in measuring external pressure.

[0060] For example, the first accommodating portion 511 can be set to 500×500×350μm, and the second accommodating portion 512 can be set to 400×400×150μm. In this way, a corresponding stepped structure is formed between the first accommodating portion 511 and the second accommodating portion 512. Furthermore, when the pressure-sensitive layer 6 is prepared in the first accommodating portion 511 with a larger space, the preparation difficulty can be reduced. This will not be elaborated further here.

[0061] In some embodiments, the orthographic projection of the second receiving portion 512 on the first substrate 1 is located within the orthographic projection of the first receiving portion 511 on the first substrate 1. When the orthographic projection of the second receiving portion 512 on the first substrate 1 is located within the orthographic projection of the first receiving portion 511, and the orthographic projection area of ​​the second receiving portion 512 is smaller than the orthographic projection area of ​​the first receiving portion 511, the first receiving portion 511 and the second receiving portion 512 can form a stepped structure. At this time, the stepped structure formed by the first receiving portion 511 and the second receiving portion 512 can not only support and limit the pressure-sensitive layer 6, but also reduce the difficulty of manufacturing the pressure-sensitive layer 6, and ensure the firmness and stability of the pressure-sensitive layer 6 installed on the second substrate 5.

[0062] In some embodiments, the orthographic projection of the thinned portion 601 on the first substrate 1 is located within the orthographic projection range of the second receiving portion 512. Thus, when the second electrode layer 4 is formed on the second side of the second substrate 5, the surface of the protrusion 410 of the second electrode layer 4 can be attached to the inner wall surface of the thinned portion 601 and the second receiving portion 512, so that the protrusion 410 of the second electrode layer 4 has good connection strength with the second substrate 5 and the thinned portion 601. In this way, when measuring external pressure, deformation can be prevented in the portion attached to the inner surface of the thinned portion 601, which helps to improve the measurement accuracy and reliability of the sensor.

[0063] For example, such as Figure 1 As shown, when the orthographic projection of the thinned portion 601 on the first substrate 1 coincides with the orthographic projection of the second receiving portion 512, the second receiving portion 512 and the thinned portion 601 have the same shape. This not only reduces the difficulty of forming the second receiving portion 512 and the thinned portion 601, but also ensures that the protrusion 410 of the second electrode layer 4 has good continuity in the thinned portion 601, which helps to improve the structural stability and measurement accuracy of the sensor.

[0064] For example, such as Figure 3 As shown, when the orthographic projection of the thinning portion 601 on the first substrate 1 is located within the orthographic projection range of the second receiving portion 512, and the orthographic projection area of ​​the thinning portion 601 is smaller than that of the second receiving portion 512, a stepped structure can be formed between the pressure-sensitive layer 6 and the first substrate 1. When the second electrode layer 4 is formed on the surface of the second substrate 5, the wrinkling effect of the second electrode layer 4 can be increased, and its connection area outside the inner surface of the thinning portion 601 can be expanded, thereby improving the connection strength between the second electrode layer 4 and the second substrate 5, which helps to improve the structural stability and measurement accuracy of the sensor.

[0065] In some embodiments, the dielectric layer 3 has a first through hole 301 corresponding to the second receiving portion 512, and the first through hole 301 covers the orthographic projection of the second receiving portion 512 on the first substrate 1.

[0066] Specifically, such as Figure 1 , Figures 3-7 , Figure 9 as well as Figure 10 As shown, the dielectric layer 3 located between the first electrode layer 2 and the second electrode layer 4 can block them. By opening a first through hole 301 in the dielectric layer 3 and making the orthographic projection of the first through hole 301 on the first substrate 1 cover the orthographic projection of the second receiving portion 512 on the first substrate 1, the dielectric constant of the dielectric layer 3 between the second electrode layer 4 inside the thinned portion 601, i.e., the recessed portion 420 of the second electrode layer 4 and the first electrode layer 2, can be reduced, thereby reducing the generation of parasitic capacitance and improving the sensitivity and response speed of the sensor.

[0067] In some embodiments, a second through hole 101 is provided through the first substrate 1 and the first electrode, and the second through hole 101 communicates with the first through hole 301.

[0068] Specifically, the second electrode layer 4 has a recessed portion 420 on the side near the first substrate 1. Thus, the first electrode layer 2, the through-hole, and the recessed portion 420 of the second electrode layer 4 can form a cavity structure. Since the first substrate 1, the first electrode layer 2, the dielectric layer 3, the second electrode layer 4, and the second substrate 5 are stacked and connected, the formed cavity structure is a sealed cavity. When external pressure acts on the side of the pressure-sensing layer 6 away from the first substrate 1, the presence of air pressure inside the cavity structure will hinder the deformation of the pressure-sensing layer 6, thereby affecting the sensor's measurement accuracy of the external pressure. Figure 4 As shown, by opening a through second via 101 in the first substrate 1 and the first electrode layer 2, the cavity structure can be connected to the external environment through the second via 101, and the pressure balance between the cavity structure and the external environment can be maintained, reducing the influence of the internal air pressure of the cavity on the measurement process and improving the accuracy of the pressure sensing layer 6 in measuring the external pressure.

[0069] Furthermore, for the sensor, since the second through hole 101 can be used to connect the cavity structure and the external environment, when fluids such as gas or liquid enter the cavity structure through the second through hole 101, they can act on the surface of the second electrode layer 4 in the thinned portion 601, thereby directly driving the second electrode layer 4 to deform and change the voltage between the first electrode layer 2 and the second electrode layer 4, and the measurement of external pressure can also be realized.

[0070] For example, when external pressure is applied to the side of the pressure-sensitive layer 6 away from the first substrate 1, the pressure-sensitive layer 6 deforms towards the first substrate 1. Since the protrusion 410 of the second electrode layer 4 is attached to the inner surface of the thinned portion 601, the distance between the second electrode layer 4 and the first electrode layer 2 within the thinned portion 601 decreases accordingly. This causes a change in the voltage of the capacitor structure formed by the first electrode layer 2 and the second electrode layer 4, converting the pressure signal into a voltage signal, thus achieving the measurement of external pressure. Because the side of the pressure-sensitive layer 6 away from the first substrate 1 has an open design, this sensor can measure not only solid pressure but also gas or liquid pressure.

[0071] For example, when external pressure enters the cavity structure through the second through-hole 101, the external pressure can directly act on the portion of the second electrode layer 4 located within the thinning portion 601, causing the second electrode layer 4 and the pressure-sensing layer 6 to deform simultaneously in a direction away from the first substrate 1. The distance between the second electrode layer 4 and the first electrode layer 2 within the thinning portion 601 will also increase accordingly. Therefore, the voltage of the capacitor structure formed by the first electrode layer 2 and the second electrode layer 4 changes, converting the pressure signal into a voltage signal, thus achieving the measurement of the external pressure. It should be noted that, since the external pressure acts directly on the surface of the second electrode layer 4, this sensor is more suitable for measuring fluids with good insulation properties (such as gases or liquids), for example, detecting air pressure or hydraulic pressure.

[0072] In some embodiments, the sensor further includes a protective layer 7, which is disposed on the side of the second substrate 5 away from the first substrate 1 and has a gap with the pressure-sensitive layer 6.

[0073] Specifically, such as Figure 5 and Figure 6 As shown, the protective layer 7 disposed on the side of the second substrate 5 away from the first substrate 1 can cover the first receiving portion 511, effectively protecting the pressure-sensing layer 6. This reduces the interference of environmental pressure on the pressure-sensing layer 6 and improves the measurement accuracy of the sensor. Specifically, since the side of the pressure-sensing layer 6 away from the first substrate 1 is covered by the protective layer 7, the sensor can measure external pressure through the second electrode layer 4 located inside the thinned portion 601. This also makes the sensor suitable for measuring the pressure of insulating fluids, expanding its application range.

[0074] More specifically, when measuring external pressure using the side of the second electrode layer 4 close to the first substrate 1, the second electrode layer 4 and the pressure-sensing layer 6 deform in the direction away from the first substrate 1 under the action of external pressure; therefore, by setting a gap between the protective layer 7 and the pressure-sensing layer 6, it is possible to prevent the pressure-sensing layer 6 from contacting the protective layer 7 after deformation, so as to prevent the protective layer 7 from affecting the measurement effect of the pressure-sensing layer 6 and thus improve the measurement accuracy of the sensor.

[0075] Furthermore, the protective layer 7, in its orthographic projection onto the first substrate 1, covers the orthographic projection of the first receiving portion 511 onto the first substrate 1, specifically as follows: Figure 5 and Figure 6 As shown, this can improve the covering and protective effect of the pressure-sensitive layer 6 in the first receiving portion 511 of the protective layer 7.

[0076] In some embodiments, the protective layer 7 has a plurality of third through holes 701, which communicate with the gap.

[0077] Specifically, when the protective layer 7 is disposed on the side of the second substrate 5 away from the first substrate 1, there is a relatively sealed gap between the pressure-sensitive layer 6 and the protective layer 7. When external pressure acts on the surface of the second electrode layer 4 located in the thinning portion 601, causing it and the pressure-sensitive layer 6 to deform in a direction away from the first substrate 1, the air pressure in the gap may hinder the deformation of the second electrode layer 4 and the pressure-sensitive layer 6, thereby affecting their measurement accuracy of external pressure. Figure 6 As shown, by opening multiple third through holes 701 in the protective layer 7, the external environment can be connected to the gap through the third through holes 701 to ensure dynamic balance between the air pressure in the gap and the external air pressure, thereby improving the measurement accuracy of the external pressure.

[0078] In some embodiments, the second electrode layer 4 and the pressure-sensitive layer 6 are provided with a fourth through hole 602, which communicates with the recess 420.

[0079] Specifically, for the sensor, the first electrode layer 2, the first through hole 301, and the recess 420 located in the second electrode layer 4 together form a cavity structure. Because this cavity structure is airtight, when external pressure acts on the surface of the pressure-sensing layer 6, the internal air pressure of the cavity structure will hinder the deformation of the pressure-sensing layer 6, affecting the sensor's accuracy in measuring external pressure. Figure 7 As shown, by opening a fourth through hole 602 in the second electrode layer 4 and the pressure sensing layer 6, the cavity structure can be connected to the external environment, so as to maintain the air pressure balance between the cavity structure and the external environment, reduce the resistance of the internal air pressure of the cavity structure to the deformation of the pressure sensing layer 6, and improve the sensing accuracy of the pressure sensing layer 6 to external pressure.

[0080] More specifically, since the fourth through hole 602 penetrates the pressure-sensing layer 6 and the second electrode layer 4 located within the thinned portion 601, it is not suitable for measuring the pressure of fluids; therefore, the sensor provided in the above embodiment is more suitable for measuring solid pressure.

[0081] In some embodiments, at least one of the second substrate 5 and the pressure-sensitive portion is provided with a cutout structure 501. At least a portion of the cutout structure 501 in the orthographic projection of the first substrate 1 surrounds the thinning portion 601 in the orthographic projection of the first substrate 1 and is located within the orthographic projection of the pressure-sensitive layer 6 in the first substrate 1.

[0082] Specifically, such as Figure 8 As shown, by providing a hollow structure 501 in at least one of the second substrate 5 and the pressure-sensitive portion, the weight of the sensor module can be reduced without affecting the sensor's measurement performance. More specifically, by having at least a portion of the hollow structure 501 surrounding the orthographic projection of the thinned portion 601 around the orthographic projection of the first substrate 1 and located within the orthographic projection of the pressure-sensitive layer 6 on the first substrate 1, the stress distribution on the surface of the pressure-sensitive layer 6 can be optimized, enhancing its overall flexibility and further improving the sensitivity of the pressure-sensitive layer 6.

[0083] In some embodiments, both the first substrate 1 and the second substrate 5 have through holes 801. The through holes 801 are provided with electrical connection portions 803 in the same direction as the through holes 801. One end of the electrical connection portion 803 in the through holes 801 of the first substrate 1 is connected to the first electrode layer 2, and the other end is exposed relative to the first substrate 1. One end of the electrical connection portion 803 in the through holes 801 of the second substrate 5 is connected to the second electrode layer 4, and the other end is exposed relative to the second substrate 5.

[0084] Specifically, such as Figures 1-10 As shown, by opening vias 801 on the first substrate 1 and the second substrate 5, and providing electrical connection portions 803 in the vias 801 with the same extension direction, the first electrode layer 2 and the second electrode layer 4 can establish electrical connection relationships with external chips and other circuit structures, thereby achieving stable transmission of electrical signals.

[0085] Furthermore, for the electrical connection portion 803 connected to the first electrode layer 2, a galvanized contact 802 can be provided at the end of the electrical connection portion 803 away from the first electrode layer 2 using wire printing or electroplating processes to provide a corresponding electrical connection position; similarly, for the electrical connection portion 803 connected to the second electrode layer 4, a galvanized contact 802 can be provided at the end of the electrical connection portion 803 away from the second electrode layer 4 using the same process to provide a corresponding electrical connection position, so as to ensure stable transmission of electrical signals.

[0086] For example, the vias 801 on the first substrate 1 and the second substrate 5 can be formed by an etching process. For example, when glass is used as the first substrate 1 and the second substrate 5, the substrate is modified by laser and blind holes are formed. Then, an etching solution (such as an etching solution based on hydrofluoric acid, sodium hydroxide or potassium hydroxide) is used to etch through the blind holes and form through holes, thereby forming the vias 801 on the first substrate 1 and the second substrate 5.

[0087] In some embodiments, the thinned portion 601 has a pressure-sensitive surface on the side facing the first substrate 1, and the pressure-sensitive surface is one of a plane, a curved surface, and a non-flat surface; specifically, as shown in... Figure 1 , Figure 9 as well as Figure 10 As shown, since the pressure-sensitive surface is located on the side of the thinning portion 601 close to the first substrate 1, the protrusion 410 of the second electrode layer 4 is in contact with the pressure-sensitive surface. When the pressure-sensitive surface deforms, the deformation state of the second electrode layer 4 is the same as that of the pressure-sensitive surface. Therefore, the pressure-sensitive surface can be selected from one of the following: a plane, a curved surface, or a non-platform surface, to meet different user needs.

[0088] For example, such as Figure 1 As shown, setting the pressure-sensitive surface as a plane not only reduces the processing difficulty of the pressure-sensitive surface, but also ensures that the first conductive layer of the second electrode layer 4 prepared on the surface of the pressure-sensitive surface has better uniformity, thereby improving the performance and reliability of the sensor.

[0089] For example, such as Figure 9 As shown, when the pressure-sensitive surface is set as a curved structure, the contact area between the first conductive layer of the second electrode layer 4 and the pressure-sensitive surface can be increased, thereby improving the connection between the first conductive layer and the pressure-sensitive layer 6. In addition, compared with the planar pressure-sensitive surface, the curved pressure-sensitive surface is more sensitive to stress and has a more significant degree of deformation. Therefore, it can more effectively sense external stress and improve the measurement accuracy and performance of the sensor.

[0090] For example, such as Figure 10 As shown, when the pressure-sensing surface is set as a non-flat surface, for example, protruding particles are provided on the surface of the pressure-sensing surface, or it is set as a continuous surface with multiple curved surfaces connected, so that there is a larger connection area between the pressure-sensing surface and the first conductive layer of the second conductive layer, and the first conductive layer can also have better deformation capability, thereby improving the measurement accuracy and sensitivity of the sensor.

[0091] In some embodiments, the thickness of the first substrate 1 is less than the thickness of the second substrate 5; the thickness of the first substrate 1 is within the range of 200-1000 μm, and the thickness of the second substrate 5 is within the range of 400-1500 μm.

[0092] Specifically, since the pressure-sensitive layer 6 is disposed in the first substrate 1, the thickness of the first substrate 1 can be set to be less than the thickness of the second substrate 5, thereby reducing the overall thickness of the sensor and achieving a thinner and lighter sensor design.

[0093] More specifically, the thickness of the first substrate 1 can be set within the range of 200-1000μm. By setting the thickness of the first substrate 1 above 200μm, the mechanical strength of the first substrate 1 can be guaranteed, so that the sensor has good compressive strength. On the other hand, setting the thickness of the first substrate 1 below 1000μm can control the overall thickness of the first substrate 1, which is conducive to realizing the thin and light design of the sensor.

[0094] More specifically, the second substrate 5 is within the range of 400-1500μm. By setting the thickness of the first substrate 1 to above 400μm, the mechanical strength of the second substrate can be improved, and relatively complete stepped holes 510 can be opened inside it to meet the preparation requirements of the pressure-sensitive layer 6. Setting the thickness of the second substrate 5 to within 1500μm can control the overall thickness of the second substrate 5, reduce material costs, and facilitate the realization of a thinner and lighter sensor design.

[0095] In a second aspect, an electronic device is also provided, including a sensor as described in any embodiment of the first aspect; specifically, since the electronic device has the sensor described above, it possesses all the advantages and beneficial effects of the sensor described above, which will not be repeated here.

[0096] More specifically, this electronic device can be widely used in consumer electronics, automotive, medical, industrial automation, aerospace, environmental monitoring, and home appliances. For example, in consumer electronics, it can be used as a pressure sensor for touchscreens in smartphones and tablets, as well as activity monitoring modules in smartwatches and fitness trackers; in the automotive sector, it is suitable for tire pressure monitoring systems, and oil and gas pressure sensors for engines and transmissions; in medical devices, it can be used as an airway pressure monitoring device in blood pressure monitors and ventilators; in industrial automation, it is suitable for control sensors for liquid and gas pressure monitoring, and liquid level monitoring devices in storage tanks and pipelines; in aerospace, it can be used for barometric altimeters and cabin pressure monitoring systems in aircraft; in environmental monitoring, it is suitable for atmospheric pressure measurement devices in meteorological stations and hydrological monitoring equipment; and in home appliances, it can be used for water level and pressure monitoring in washing machines and refrigerant pressure monitoring in refrigerators and air conditioners. This diverse range of applications demonstrates the device's high precision, reliability, and wide applicability.

[0097] A third aspect of this application also provides a method for fabricating a sensor, such as... Figures 11A-12 As shown, the preparation method includes:

[0098] S100: A first substrate 1 is provided, and a first electrode layer 2 and a dielectric layer 3 are sequentially formed on one side of the first substrate 1, and a first through hole 301 is formed in the dielectric layer 3;

[0099] In this step, such as Figures 11A-11CAs shown, the first substrate 1 can be a pre-fabricated glass substrate. In specific implementation, a first electrode layer 2 is first formed by sputtering on the surface of the first substrate 1 using a PVD process. Then, a dielectric layer 3 is coated on the electrode layer using a coating and developing process, and a first through-hole 301 is processed on the surface of the dielectric layer 3 using an exposure and developing process. This not only ensures the precise formation of the first electrode layer 2 and the dielectric layer 3, but also provides a reliable foundation for the fabrication of subsequent structures.

[0100] Furthermore, after providing the first substrate 1, an acidic or alkaline etching solution can be used to etch corresponding vias 801 on the first substrate 1, so that when the first electrode layer 2 is subsequently formed, corresponding electrical connection portions 803 can be formed simultaneously within the vias 801.

[0101] S200: A second substrate 5 is provided, a first receiving portion 511 is formed on a first side of the second substrate 5, and a boss structure 9 protruding toward the first side is formed in the first receiving portion 511.

[0102] In this step, such as Figure 11D As shown, the second substrate 5 can be a pre-fabricated glass substrate. In a specific implementation, a first receiving portion 511 is formed on the first side of the second substrate 5 through laser modification and / or etching processes, and a boss structure 9 protruding towards the first side is processed in the first receiving portion 511, while a recessed area is formed around the boss structure 9. The boss structure 9 can provide a precise fabrication position for the first conductive layer of the second electrode layer 4 and the pressure-sensitive layer 6, while the recessed area can enhance the connection strength and reliability between the pressure-sensitive layer 6 and the second substrate 5, thereby improving the overall performance and stability of the sensor.

[0103] Furthermore, after providing the second substrate 5, an acidic or alkaline etching solution can be used to etch corresponding vias 801 on the second substrate 5, so that when the second electrode layer 4 is subsequently formed, corresponding electrical connection portions 803 can be formed simultaneously within the vias 801.

[0104] S300: A first conductive layer and a pressure-sensitive layer 6 are sequentially formed in the first receiving portion 511, such that the first conductive layer covers the boss structure 9 and the pressure-sensitive layer 6 covers the first conductive layer.

[0105] In this step, such as Figure 11EAs shown, the first conductive layer is sputtered on the surface of the boss structure 9 using PVD process, which reduces the difficulty of fabricating the subsequent second electrode layer 4 and can block the etching solution in the subsequent etching process, thereby promoting the formation of the thinned portion 601 and ensuring that the pressure-sensitive layer 6 has good uniformity. Subsequently, the pressure-sensitive layer 6 is deposited in the first receiving portion 511 by PECVD process, covering the first conductive layer and embedding its edge into the recessed area. This not only enhances the connection between the pressure-sensitive layer 6 and the second substrate 5, but also forms a high-density and highly uniform pressure-sensitive layer 6, which helps to improve the performance and reliability of the sensor.

[0106] Furthermore, in order to reduce the leakage rate of the sensor and improve the pressure sensing sensitivity and application flexibility of the pressure sensing layer 6, the pressure sensing layer 6 can be made of silicon nitride material with different silicon-nitrogen ratios according to actual needs. Using silicon nitride can not only optimize the mechanical and electrical properties of the pressure sensing layer 6, but also significantly improve the measurement accuracy and applicability of the sensor, which will not be elaborated here.

[0107] For example, the thickness of the first conductive layer can be 0.02μm-2μm, which will not be elaborated here.

[0108] S400: A second receiving portion 512 is formed on the second side of the second substrate 5 so that the second receiving portion 512 communicates with the first receiving portion 511. The boss structure 9 is etched away so that a thinning portion 601 is formed on the surface of the pressure-sensitive layer 6 away from the first side, so that the first conductive layer is located in the thinning portion 601 and is relatively exposed.

[0109] In this step, such as Figure 11F As shown, the second side of the second substrate 5 is disposed opposite to the first side. In a specific implementation, a second receiving portion 512 can be formed on the second side of the second substrate 5 by etching, so that it is connected to the first receiving portion 511. Subsequently, as the etching process continues, the pre-prepared boss structure 9 in the first receiving portion 511 can be removed, thereby forming a thinning portion 601 on the side of the pressure-sensitive layer 6 close to the first substrate 1. When the first conductive layer in the thinning portion 601 is completely exposed, the etching process stops. At this time, the first conductive layer can effectively block the residual etching liquid from further etching the surface of the pressure-sensitive film, thereby ensuring the thinning effect and surface uniformity of the pressure-sensitive film, and improving the performance and reliability of the sensor.

[0110] S500: A second conductive layer is formed on the second side of the second substrate 5 so that the second conductive layer is integrally connected with the edge of the first conductive layer to form a second electrode layer 4; wherein, corresponding protrusions 410 and recesses 420 are formed on opposite sides of the second electrode layer 4, and the surfaces of the protrusions 410 are respectively attached to the second receiving portion 512 and the thinning portion 601.

[0111] In this step, such as Figure 11G A second conductive layer can be sputtered on the second side of the second substrate 5 using a PVD process. Subsequently, in order to make the second conductive layer electrically connected to the edge of the first conductive layer and form a complete second electrode layer 4, an electroplating process can be applied to electroplat the inner surfaces of the thinned portion 601 and the second receiving portion 512 with conductors of the same material as the first and second conductive layers, thereby forming opposing protrusions 410 and recesses 420. This not only ensures good connection strength between the surface of the protrusion 410 and the second receiving portion 512 and the thinned portion 601, but also significantly improves the measurement effect of the second electrode layer 4 on external pressure.

[0112] Furthermore, when forming the second conductive layer on the second side of the second substrate 5, a corresponding electrical connection portion 803 can be simultaneously formed in the via 801 of the second substrate 5 so as to establish a good electrical connection relationship with the subsequent circuit structure such as the chip.

[0113] S600: Bond the side of the dielectric layer 3 away from the first substrate 1 to the second side of the second substrate 5, so that the recess 420 corresponds to the first through hole 301.

[0114] In this step, such as Figure 11H As shown, the side of the dielectric layer 3 furthest from the first substrate 1 is bonded to the second side of the second substrate 5 using a bonding process, ensuring good connection strength between the dielectric layer 3 and the second electrode layer 4. During the bonding process, the recessed portion 420 of the second electrode layer 4 must correspond to the first through-hole 301, thereby maintaining a large gap between the first conductive portion of the second electrode layer 4 located within the thinned portion 601 and the first electrode layer 2. This not only helps to improve the sensitivity of the capacitive structure in the sensor, but also significantly enhances the accuracy of the sensor in measuring external pressure.

[0115] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0116] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0117] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0118] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0119] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0120] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A sensor, characterized in that, include: A first substrate, a first electrode layer, a dielectric layer, a second electrode layer, and a second substrate are stacked, wherein the second substrate has stepped holes. as well as A pressure-sensitive layer is embedded in the stepped hole, and a thinning portion is recessed on the side of the pressure-sensitive layer near the first substrate to reduce the local thickness of the pressure-sensitive layer. One side of the second electrode layer protrudes in a direction away from the first substrate to form a protrusion, and the protrusion is in contact with the inner surface of the thinned portion; the other side of the second electrode layer is recessed in a direction away from the first substrate to form a recess, and the recess corresponds to the protrusion.

2. The sensor according to claim 1, characterized in that, The pressure-sensitive layer is made of silicon nitride, and the thickness of the pressure-sensitive layer is within the range of 0.02-2μm.

3. The sensor according to claim 1, characterized in that, The stepped hole includes: A first receiving portion is formed on a first side of the second substrate; the pressure-sensitive layer is embedded within the first receiving portion; and The second receiving portion is formed on the second side of the second substrate and communicates with the first receiving portion; the protrusion penetrates the second receiving portion and is in contact with the inner surface of the second receiving portion; The second side is closer to the first substrate than the first side.

4. The sensor according to claim 3, characterized in that, The second receiving portion is projected onto the first substrate in the same direction as the first receiving portion in the same direction as the first substrate. The projection of the thinned portion onto the first substrate is located within the projection of the second receiving portion onto the first substrate.

5. The sensor according to claim 4, characterized in that, The dielectric layer has a first through hole corresponding to the second receiving portion, and the orthographic projection of the first through hole onto the first substrate covers the orthographic projection of the second receiving portion onto the first substrate.

6. The sensor according to claim 5, characterized in that, The first substrate and the first electrode have a second through hole through which the second through hole communicates with the first through hole.

7. The sensor according to claim 6, characterized in that, Also includes: A protective layer is disposed on the side of the second substrate away from the first substrate, and there is a gap between it and the pressure-sensitive layer; The protective layer's orthographic projection on the first substrate covers the orthographic projection of the first receiving portion on the first substrate.

8. The sensor according to claim 7, characterized in that, The protective layer has multiple third through holes, which are connected to the gap.

9. The sensor according to any one of claims 1-6, characterized in that, The second electrode layer and the pressure-sensitive layer are connected by a fourth through hole, which communicates with the recessed portion.

10. The sensor according to claim 1, characterized in that, At least one of the second substrate and the pressure-sensitive part has a hollow structure. At least a portion of the hollow structure in the orthographic projection of the first substrate surrounds the thinned portion in the orthographic projection of the first substrate and is located within the orthographic projection of the pressure-sensitive layer in the first substrate.

11. The sensor according to claim 1, characterized in that, Both the first substrate and the second substrate have vias, and each via has an electrical connection portion extending in the same direction as its extension. One end of the electrical connection portion in the via of the first substrate is connected to the first electrode layer, and the other end is exposed relative to the first substrate. One end of the electrical connection portion within the via of the second substrate is connected to the second electrode layer, while the other end is exposed relative to the second substrate.

12. The sensor according to claim 1, characterized in that, The thinned portion has a pressure-sensitive surface on the side facing the first substrate, and the pressure-sensitive surface is one of a plane, a curved surface, or a non-flat surface.

13. The sensor according to claim 1, characterized in that, The thickness of the first substrate is less than the thickness of the first substrate; The thickness of the first substrate is within the range of 200-1000 μm, and the thickness of the second substrate is within the range of 400-1500 μm.

14. An electronic device, characterized in that, Includes the sensor as described in any one of claims 1-13.

15. A method for manufacturing a sensor, characterized in that, include: A first substrate is provided, on one side of the first substrate a first electrode layer and a dielectric layer are sequentially formed, and a first through-hole is formed in the dielectric layer; A second substrate is provided, a first receiving portion is formed on a first side of the second substrate, and a boss structure protruding toward the first side is formed in the first receiving portion; A first conductive layer and a pressure-sensitive layer are sequentially formed in the first accommodating portion, such that the first conductive layer covers the boss structure and the pressure-sensitive layer covers the first conductive layer. A second receiving portion is formed on the second side of the second substrate to communicate with the first receiving portion. The boss structure is etched away to form a thinning portion on the surface of the pressure-sensitive layer away from the first side, so that the first conductive layer is located in the thinning portion and relatively exposed. A second conductive layer is formed on the second side of the second substrate, so that the second conductive layer is integrally connected with the edge of the first conductive layer to form a second electrode layer; wherein, corresponding protrusions and recesses are formed on opposite sides of the second electrode layer, and the surfaces of the protrusions are respectively attached to the second receiving portion and the thinning portion; The dielectric layer is bonded to the second side of the second substrate from the side away from the first substrate, so that the recess corresponds to the first through hole.

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