Pressure sensor and pressure-sensitive panel

Abstract

A pressure sensor and a pressure-sensitive panel, which belong to the technical field of electronic sensing. The pressure sensor comprises a substrate (300) and an induction transistor (100). The induction transistor (100) comprises a first active layer (110), a first induction gate (120) and a cavity structure (10), wherein the first active layer (110) is arranged on the substrate (300); the first induction gate (120) is arranged on the side of the first active layer (110) that faces away from the substrate (300); and the cavity structure (10) is arranged between the first active layer (110) and the first induction gate (120), and overlaps with the first induction gate (120). When different pressing forces are applied to the first induction gate (120), the output currents of a second electrode (160) are also different, thereby implementing the measurement of different pressing forces. A capacitance change directly acts on the first induction gate (120) of the induction transistor (100), and therefore voltage and current signals are converted and amplified, thereby improving the sensitivity of the pressure sensor.

Description

Pressure sensors, pressure sensing panels Technical Field

[0001] The present disclosure relates to the field of electronic sensing technology, and in particular to a pressure sensor and a pressure sensing panel. Background Art

[0002] A sensor is a detection device that can sense the information being measured and convert the sensed information into electrical signals or other required forms of information output according to certain rules to meet the requirements of information output, processing, storage, display, recording and control.

[0003] Existing sensors use silicon-based MEMS technology, enabling internal structures on the micron or even nanometer scale. However, silicon-based technology cannot meet large-area requirements and has relatively low sensitivity. Furthermore, sensors require specialized materials such as piezoresistive or piezoelectric materials to achieve pressure detection, but these specialized materials are relatively expensive.

[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 prior art known to ordinary technicians in the field.

[0005] Summary of the Invention

[0006] The present disclosure provides a pressure sensor and a pressure sensing panel with high detection sensitivity and low production cost.

[0007] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by practice of the present disclosure.

[0008] According to one aspect of the present disclosure, a pressure sensor is provided, comprising a substrate and a sensing transistor, wherein the sensing transistor comprises: a first active layer disposed on the substrate;

[0009] a first sensing gate, disposed on a side of the first active layer facing away from the substrate;

[0010] The cavity structure is arranged between the first active layer and the first sensing gate and overlaps with the first sensing gate.

[0011] In an exemplary embodiment of the present disclosure, the sensing transistor further includes:

[0012] A first insulating layer is provided between the first active layer and the first sensing gate and overlaps with the cavity structure;

[0013] a second insulating layer covering the first active layer and overlapping the cavity structure;

[0014] Wherein, at least a portion of the cavity structure is arranged inside at least one of the first insulating layer and the second insulating layer.

[0015] In an exemplary embodiment of the present disclosure, the first insulating layer includes:

[0016] a first separation layer, disposed between the first active layer and the first sensing gate;

[0017] The first separation layer is provided with a sacrificial etching hole, the sacrificial etching hole is connected to the cavity structure, and the cavity structure is provided in the first separation layer.

[0018] In an exemplary embodiment of the present disclosure, the first separation layer includes:

[0019] a main body portion, disposed between the first active layer and the first sensing gate;

[0020] The protrusion is protruding from a side of the main body away from the substrate. The sacrificial etching hole is provided in the protrusion. The protrusion and the second insulating layer form the cavity structure.

[0021] In an exemplary embodiment of the present disclosure, the orthographic projection of the sacrificial etching hole on the substrate is located outside the orthographic projection of the first active layer on the substrate.

[0022] In an exemplary embodiment of the present disclosure, the first insulating layer further includes:

[0023] The first planar layer is disposed between the first separation layer and the first sensing gate and can block the sacrificial etching hole.

[0024] In an exemplary embodiment of the present disclosure, the sensing transistor further includes:

[0025] The first insulating covering layer is arranged on a side of the first insulating layer away from the substrate, and the first insulating covering layer covers the first sensing gate.

[0026] In an exemplary embodiment of the present disclosure, the sensing transistor further includes:

[0027] The first electrode and the second electrode are provided on a surface of the second insulating layer facing the substrate and are electrically connected to the via holes of the first active layer.

[0028] In an exemplary embodiment of the present disclosure, the second insulating layer includes:

[0029] a first gate insulating layer, disposed on a side of the first active layer facing away from the substrate, the first electrode and the second electrode being electrically connected to the first active layer through the first gate insulating layer;

[0030] A first interlayer insulating layer is provided between the first gate insulating layer and the first insulating layer. The first interlayer insulating layer covers the first electrode and the second electrode. The first interlayer insulating layer and the first insulating layer are close to each other on one side to form the cavity structure.

[0031] In an exemplary embodiment of the present disclosure, the sensing transistor further includes:

[0032] a second sensing gate, disposed between the first active layer and the substrate, and overlapping the first active layer;

[0033] The first buffer layer covers the second sensing gate, and the first active layer is arranged on a surface of the first buffer layer away from the substrate.

[0034] In an exemplary embodiment of the present disclosure, the orthographic projection of the cavity structure on the substrate is located inside the orthographic projection of the first active layer on the substrate.

[0035] In an exemplary embodiment of the present disclosure, a boundary of an orthographic projection of the cavity structure on the substrate is located inside a boundary of an orthographic projection of the first sensing gate on the substrate.

[0036] In an exemplary embodiment of the present disclosure, a projection of the cavity structure relative to the substrate is a circular structure.

[0037] In an exemplary embodiment of the present disclosure, the cavity structure is filled with gas; or,

[0038] The cavity structure is a vacuum structure.

[0039] In an exemplary embodiment of the present disclosure, the sensing transistor further includes:

[0040] The pressing portion is arranged on a side of the first sensing grid away from the substrate and is corresponding to the cavity structure.

[0041] In an exemplary embodiment of the present disclosure, there are multiple cavity structures, and the multiple cavity structures are arranged in parallel and spaced apart between the first active layer and the first sensing gate, and the orthographic projections of the multiple cavity structures on the substrate are located inside the orthographic projection of the first sensing gate on the substrate.

[0042] According to another aspect of the present disclosure, a pressure sensing panel is provided, comprising the above-mentioned pressure sensor.

[0043] In an exemplary embodiment of the present disclosure, there are multiple pressure sensors, and the multiple pressure sensors are arranged in an array along row and column directions. The top gates of the sensing transistors in the same column are connected through a scan line, the first electrodes of the sensing transistors in the same row are connected through a data line, and the second electrodes of the sensing transistors in the same row are connected through an output line.

[0044] In an exemplary embodiment of the present disclosure, the pressure sensing panel further includes:

[0045] A switch transistor is provided on the substrate, and the second electrode of the sensing transistor is connected to the output line through the switch transistor.

[0046] In an exemplary embodiment of the present disclosure, the switching transistor includes:

[0047] a second active layer, disposed on the substrate, the second active layer being electrically connected to the first active layer and disposed on the same layer as the first active layer;

[0048] The first switch gate is arranged on a side of the second active layer away from the substrate and is arranged in the same layer as the first sensing gate.

[0049] According to another aspect of the present disclosure, a method for manufacturing a pressure sensor is provided, the method comprising the following steps:

[0050] forming a first active layer on a substrate;

[0051] forming a cavity structure on a side of the first active layer facing away from the substrate;

[0052] A first sensing gate is formed on a side of the cavity structure facing away from the substrate and overlapping with the cavity structure.

[0053] In an exemplary embodiment of the present disclosure, forming a cavity structure on a side of the first active layer facing away from the substrate includes the following steps:

[0054] forming a second insulating layer on a side of the first active layer facing away from the substrate;

[0055] forming a sacrificial layer on a side of the second insulating layer facing away from the substrate and overlapping with the first sensing gate and the second insulating layer;

[0056] forming a first insulating layer for covering the sacrificial layer on a side of the sacrificial layer facing away from the substrate;

[0057] The sacrificial layer is removed to form a cavity structure between the first insulating layer and the second insulating layer.

[0058] In an exemplary embodiment of the present disclosure, removing the sacrificial layer comprises the following steps:

[0059] forming a first separation layer on a side of the sacrificial layer facing away from the substrate;

[0060] forming a sacrificial etching hole in the first separation layer;

[0061] Passing an etching solution into the sacrificial etching hole, so that the etching solution corrodes the sacrificial layer to form a cavity structure between the first separation layer and the second insulating layer;

[0062] A first planar layer for blocking the sacrificial etching hole is formed on a side of the first separation layer facing away from the substrate.

[0063] The pressure sensor and pressure sensing panel provided by the embodiments of the present disclosure have a cavity structure between the first active layer and the first sensing gate. Under the action of external pressure, the cavity structure is deformed, causing the capacitance value between the first active layer and the first sensing gate to change, and the output current of the second electrode in the sensing transistor to change. According to the output current of the second electrode, the pressing force of the first sensing gate can be detected. The output current of the second electrode is different depending on the pressing force applied to the first sensing gate, thereby realizing the detection of different pressing forces. Since the capacitance change directly acts on the first sensing gate of the sensing transistor, the voltage and current signals are converted and amplified, thereby improving the sensitivity of the pressure sensor. In addition, the pressure sensor can detect the pressing force only through the cavity structure, without the need for complex special materials, saving production costs.

[0064] 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 disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings are incorporated into 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 drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0066] FIG1 is a schematic structural diagram of a pressure sensor according to a first embodiment of the present disclosure before being pressed;

[0067] FIG2 is a circuit diagram of a pressure sensor according to a first embodiment of the present disclosure;

[0068] FIG3 is a schematic structural diagram of the pressure sensor according to the first embodiment of the present disclosure when pressed;

[0069] FIG4 is a top view of the pressure sensor according to the first embodiment of the present disclosure;

[0070] FIG5 is a schematic structural diagram of the first sensing gate in FIG4 ;

[0071] FIG6 is a schematic structural diagram of the first separation layer in FIG4 ;

[0072] FIG7 is a schematic structural diagram of the first active layer in FIG4 ;

[0073] FIG8 is a schematic structural diagram of the first electrode in FIG4 ;

[0074] FIG9 is a schematic structural diagram of the second electrode in FIG4 ;

[0075] FIG10 is a schematic structural diagram of the second sensing gate in FIG4 ;

[0076] FIG11 is a circuit diagram of a pressure sensing panel according to a first embodiment of the present disclosure;

[0077] FIG12 is a flow chart of a method for manufacturing a pressure sensor according to a first embodiment of the present disclosure;

[0078] FIG13 is a schematic structural diagram of a pressure sensor according to a second embodiment of the present disclosure;

[0079] FIG14 is a schematic structural diagram of a pressure sensor according to a third embodiment of the present disclosure;

[0080] FIG15 is a circuit diagram of a pressure sensor according to a fourth embodiment of the present disclosure;

[0081] FIG16 is a schematic structural diagram of a pressure sensor according to a fourth embodiment of the present disclosure.

[0082] 100, sensing transistor; 200, switching transistor; 300, substrate;

[0083] 10. Cavity structure; 110. First active layer; 120. First sensing gate; 130. First insulating layer; 131. First separation layer; 1311. Sacrificial etching hole; 132. First planarization layer; 140. First insulating cover layer; 150. First electrode; 160. Second electrode; 170. Second insulating layer; 171. First gate insulating layer; 172. First interlayer insulating layer; 180. Second sensing gate; 190. First buffer layer; 20. Pressing portion;

[0084] 210, second active layer; 220, first switch gate; 231, second separation layer; 232, second planarization layer; 240, second insulating cover layer; 250, third electrode; 260, fourth electrode; 271, second gate insulating layer; 272, second interlayer insulating layer; 280, second switch gate; 290, second buffer layer. DETAILED DESCRIPTION

[0085] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0086] In addition, the accompanying drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0087] Example 1

[0088] The present disclosure provides a pressure sensor, as shown in FIG1 . The pressure sensor includes a substrate 300 and a sensing transistor 100, specifically a thin film transistor (TFT). The sensing transistor 100 includes a first active layer (Active) 110, a first sensing gate (Top Gate, TG) 120, and a cavity structure 10. The first active layer 110 is disposed on the substrate 300 and may also be referred to as a channel layer. The first sensing gate 120 is disposed on a side of the first active layer 110 facing away from the substrate 300. The cavity structure 10 is disposed between the first active layer 110 and the first sensing gate 120 and overlaps with the first sensing gate 120.

[0089] As shown in Figure 2, after a scanning voltage is applied to the first sensing gate 120, a capacitor-like structure is formed between the first sensing gate 120 and the first active layer 110, with the first sensing gate 120 and the first active layer 110 serving as the two plates of the capacitor structure. Since the capacitance of a parallel plate capacitor is C = εS / d, where ε is the relative dielectric constant, S is the area of ​​the plates facing each other, and d is the distance between the two plates, as shown in Figure 3, when a user presses the first sensing gate 120, the distance d between the two plates of the first sensing gate 120 and the first active layer 110 changes, causing the capacitance per unit area of ​​the first gate layer to also change.

[0090] According to the output current of the second electrode 160 Among them, μ n is the mobility of carriers in the sensing transistor 100, C oxis the capacitance per unit area of ​​the first sensing gate 120, V T is the threshold voltage of the sensing transistor 100, W is the channel width of the sensing transistor 100, L is the channel length of the sensing transistor 100, V GS is the voltage difference between the first sensing gate 120 and the second electrode 160. As the capacitance C per unit area of ​​the first sensing gate 120 increases, ox changes, the output current I of the second electrode 160 DS Also changes.

[0091] Therefore, the pressure sensor provided in this embodiment has a cavity structure 10 between the first active layer 110 and the first sensing gate 120. Under the action of external pressure, the cavity structure 10 deforms, causing the capacitance between the first active layer 110 and the first sensing gate 120 to change. This changes the output current of the second electrode 160 in the sensing transistor 100. Based on the output current of the second electrode 160, the pressure applied to the first sensing gate 120 can be detected. Different pressures applied to the first sensing gate 120 result in different output currents from the second electrode 160, thereby enabling detection of different pressures. Because the capacitance change directly acts on the first sensing gate 120 of the sensing transistor 100, the voltage and current signals are converted and amplified, thereby improving the sensitivity of the pressure sensor. In addition, the pressure sensor can detect pressure using only the cavity structure 10, eliminating the need for complex special materials and saving production costs.

[0092] For example, when the user presses the first sensing gate 120, the first sensing gate 120 moves closer to the first active layer 110, and the distance d between the two corresponding plates of the first sensing gate 120 and the first active layer 110 becomes smaller, and the capacitance value C per unit area of ​​the first gate layer is ox becomes larger, thereby making the output current I DS It also becomes larger, and the current sensed by the external detection circuit is also larger, which plays a role in increasing the strength of the detection signal and improving the sensitivity of the pressure sensor.

[0093] It should be noted that the pressure sensor provided in this embodiment can be applied to intelligent pressure-sensitive surfaces. Specifically, the pressure sensor can be applied to the intelligent skin of a robot, or the pressure sensor can be applied to biometric fields such as fingerprint recognition. For example, pressure detection can be performed on the surface of the device according to the position of valleys and ridges in the fingerprint, or the pressure sensor can be applied to intelligent medical fields related to human health. For example: for human activities such as breathing, heartbeat, blood flow, and expansion and contraction of the lungs, the pressure sensor effectively converts the mechanical energy generated by these human activities into electrical signals to realize the detection of various health indicators of the human body.

[0094] In one embodiment, as shown in FIG1 , the substrate 300 may be a flexible substrate, such as plastic, glass, etc. The plastic may be polyimide, and the use of glass-based technology may achieve large-area and array formation to meet the user's large-size requirements.

[0095] In one embodiment, the orthographic projection of the cavity structure 10 on the substrate 300 is located inside the orthographic projection of the first active layer 110 on the substrate 300 .

[0096] In this manner, the size of the first active layer 110 is larger than that of the cavity structure 10. The first active layer 110 can provide a relatively large and complete plane for the side of the cavity structure 10 facing the substrate 300. That is, the bottom of the cavity structure 10 has good foundation stability, facilitating the formation of the cavity structure 10 above the first active layer 110. At the same time, the height of the cavity structure 10 can also be ensured to have a certain degree of stability.

[0097] The first active layer 110 may be made of materials such as amorphous silicon, polycrystalline silicon, and oxide, for example, indium gallium zinc oxide.

[0098] In one embodiment, as shown in Figures 1 and 4 , the boundary of the orthographic projection of the cavity structure 10 on the substrate 300 is located inside the boundary of the orthographic projection of the first sensing gate 120 on the substrate 300. All pressure applied to the first sensing gate 120 causes deformation of the cavity structure 10, thereby improving the detection sensitivity of the pressure sensor.

[0099] Specifically, as shown in Figures 4-6, the first sensing gate 120 includes a base portion and a functional portion. The base portion is disposed on the side of the first active layer 110 facing away from the substrate 300, and the functional portion is connected to the base portion. The first top gate has two parts, the base portion and the functional portion, forming a basic planar capacitor between the base portion and the first active layer 110. The functional portion corresponds to the cavity structure 10. When the functional portion is pressed, the cavity structure 10 deforms, causing the capacitance between the first sensing gate 120 and the first active layer 110 to change.

[0100] The projection of the functional portion relative to the substrate 300 and the projection of the cavity structure 10 relative to the substrate 300 coincide. That is, the size of the functional portion and the size of the cavity structure 10 are the same. All pressure applied to the functional portion can cause deformation of the cavity structure 10, thereby improving the detection sensitivity of the pressure sensor.

[0101] In one embodiment, as shown in FIG1 , the sensing transistor 100 further includes a first insulating layer 130, which is disposed between the first active layer 110 and the first sensing gate 120. In this manner, the first insulating layer 130 serves to isolate and insulate the first active layer 110 and the first sensing gate 120, thereby preventing electrical contact between the first active layer 110 and the first sensing gate 120.

[0102] In one embodiment, the sensing transistor 100 further includes a second insulating layer 170, which covers the first active layer 110 and overlaps the cavity structure 10. In this manner, the second insulating layer 170 serves to isolate and insulate the first active layer 110 from the first insulating layer 130, further preventing electrical contact between the first active layer 110 and the first sensing gate 120.

[0103] At least a portion of the cavity structure 10 is disposed inside at least one of the first insulating layer 130 and the second insulating layer 170 .

[0104] Specifically, the cavity structure 10 may be entirely disposed in the first insulating layer 130 , or entirely disposed in the second insulating layer 170 , or the cavity structure 10 is a space enclosed by the first insulating layer 130 and the second insulating layer 170 .

[0105] In one embodiment, the first insulating layer 130 includes a first spacer layer 131, which is disposed between the first active layer 110 and the first sensing gate 120. The first spacer layer 131 can separate the first active layer 110 from the first sensing gate 120, thereby isolating and insulating the first active layer 110 from the first sensing gate 120, thereby preventing electrical contact between the first active layer 110 and the first sensing gate 120, and ensuring normal operation of the sensing transistor 100.

[0106] The first separation layer 131 is provided with a sacrificial etching hole 1311 . The sacrificial etching hole 1311 is connected to the cavity structure 10 . The cavity structure 10 is provided in the first separation layer 131 .

[0107] Specifically, the cavity structure 10 can be formed by etching a sacrificial layer. The sacrificial layer is first placed between the second insulating layer 170 and the first spacer layer 131. The second insulating layer 170, the sacrificial layer, and the first spacer layer 131 are sequentially stacked. The sacrificial layer can be made of a gold material such as copper or molybdenum, or an organic polymer material. The thickness of the sacrificial layer is approximately 100 nm to 1500 nm. A sacrificial etchant is then passed into the sacrificial etched hole 1311, allowing the sacrificial etchant to enter between the first spacer layer 131 and the second insulating layer 170 and etch the sacrificial layer. As an underlying thin film, the sacrificial layer serves only as a separation layer, thereby forming the cavity structure 10 between the first spacer layer 131 and the first active layer 110.

[0108] In some other embodiments, the cavity structure 10 can also be formed in various ways. For example, the second insulating layer 170 can be recessed in a direction toward the substrate 300 to form a receiving groove, which is used to accommodate and fill the sacrificial layer. The receiving groove is then covered with the first insulating layer 130 having the sacrificial etched hole 1311, and the sacrificial layer is then removed. At this time, the cavity structure 10 is disposed within the second insulating layer 170. Alternatively, the second insulating layer 170 can be recessed in a direction toward the substrate 300 to form the receiving groove, and the first insulating layer 130 can be recessed away from the substrate 300 to form the filling groove. The receiving groove and the filling groove are joined to form a receiving space, which is used to fill the sacrificial layer. After the sacrificial layer is removed, the cavity structure 10 is disposed between the first insulating layer 130 and the second insulating layer 170.

[0109] In one embodiment, as shown in Figures 4-7 , the orthographic projection of the sacrificial etched hole 1311 on the substrate 300 is located outside the orthographic projection of the first active layer 110 on the substrate 300. In this manner, the opening and blocking positions of the sacrificial etched hole 1311 are staggered with the position of the cavity structure 10, thereby improving the structural strength and stability of the cavity structure 10.

[0110] Of course, the orthographic projection of the sacrificial etched hole 1311 on the substrate 300 may also be located inside the orthographic projection of the first active layer 110 on the substrate 300. This embodiment does not limit the position of the sacrificial etched hole 1311 relative to the cavity structure 10 and may be adjusted according to actual production conditions. In addition, FIG1 and FIG4 present the structures of the various film layers in two different forms, and only some of the structures correspond to each other, not all of them.

[0111] If there is only one sacrificial etching hole 1311, the etching liquid can only be introduced through this one sacrificial etching hole 1311, resulting in a relatively long etching time for the sacrificial layer. To solve this problem, multiple sacrificial etching holes 1311 are provided, each corresponding to the cavity structure 10. In this way, the etching liquid can be introduced into multiple sacrificial etching holes 1311 simultaneously, increasing the amount of etching liquid introduced, shortening the etching time of the sacrificial layer, and thus improving manufacturing efficiency.

[0112] In one embodiment, the first spacer layer 131 includes a main portion and a protruding portion. The main portion is disposed between the first active layer 110 and the first sensing gate 120. The protruding portion is connected to the main portion and protrudes from the side of the main portion facing away from the substrate 300. A sacrificial etched hole 1311 is disposed in the protruding portion. The protruding portion and the second insulating layer 170 form a cavity structure 10.

[0113] The main body is a flat structure, and the protrusion protrudes from the main body. Thus, the first separator layer 131 has an overall uneven structure. This uneven structure is fully utilized, and the area between the protrusion and the second insulating layer 170 can accommodate a sacrificial layer. Sacrificial etching holes 1311 are provided in the protrusions so that they correspond to the sacrificial layer. When etching solution is injected through sacrificial etching holes 1311, the sacrificial layer can be directly etched, thereby forming a cavity structure 10 in the space previously occupied by the sacrificial layer.

[0114] In one embodiment, as shown in FIG. 1 , the first insulating layer 130 further includes a first planar layer 132 . The first planar layer 132 is disposed between the first separation layer 131 and the first sensing gate 120 and can block the sacrificial etching hole 1311 .

[0115] The first planar layer 132 can be made of an organic polymer material, such as photoresist. Since the sacrificial etched hole 1311 serves as a process hole, the side of the first planar layer 132 facing the substrate 300 can block the sacrificial etched hole 1311, thus forming a closed cavity structure 10. Furthermore, the side of the first planar layer 132 facing away from the substrate 300 is flat, facilitating the formation and placement of the first sensing gate 120.

[0116] It can be understood that the first flat layer 132 can also extend to the interior of the cavity structure 10, but will not fill the cavity structure 10. The part of the first flat layer 132 extending to the interior of the cavity structure 10 can contact the second insulating layer 170, and to a certain extent play a role in supporting the part of the first flat layer 132 located outside the cavity structure 10.

[0117] In one embodiment, the projection of the cavity structure 10 relative to the substrate 300 is a circular structure.

[0118] Compared to a rectangular parallelepiped structure, the cylindrical cavity structure 10 has no dead corners on its inner wall, which facilitates the flow of etching liquid and facilitates the rapid formation of the cavity structure 10. Furthermore, after the cavity structure 10 is formed, the circumferential force on the inner wall of the cavity structure 10 is uniform, thereby improving the structural stability of the cavity structure 10.

[0119] In one embodiment, the cavity structure 10 can be filled with gas, specifically air, which has a relatively low production cost, or the cavity structure 10 is a vacuum structure, and the cavity structure 10 is vacuumed through the sacrificial etching hole 1311, which can extend the service life of the cavity structure 10.

[0120] In one embodiment, as shown in FIG. 1 , the sensing transistor 100 further includes a first insulating cover layer 140 . The first insulating cover layer 140 is disposed on a side of the first insulating layer 130 facing away from the substrate 300 . The first insulating cover layer 140 covers the first sensing gate 120 .

[0121] Since the first sensing gate 120 needs to be pressed, the first insulating cover layer 140 covers the first sensing gate 120 to prevent the first sensing gate 120 from being directly exposed. The first insulating cover layer 140 serves to isolate and protect the first sensing gate 120 .

[0122] In one embodiment, as shown in FIG. 1 , FIG. 4 , and FIG. 7 - FIG. 9 , the sensing transistor 100 further includes a first electrode 150 and a second electrode 160 . The first electrode 150 and the second electrode 160 are disposed on a surface of the second insulating layer 170 facing the substrate 300 and are electrically connected to the first active layer 110 through via holes.

[0123] The first electrode 150 is specifically a source electrode (S), and the second electrode 160 is specifically a drain electrode (D). The first electrode 150 and the second electrode 160 can be made of one of molybdenum, copper, aluminum, titanium, and niobium, or a combination of two or more. They can also be transparent electrode materials such as indium tin oxide (ITO). The first electrode 150 can be connected to a data line for applying a driving voltage, and the second electrode 160 can be connected to an output line for outputting current.

[0124] In one embodiment, the second insulating layer 170 specifically includes a first gate insulating layer (Gate insulator, GI1) 171, which is arranged on the side of the first active layer 110 away from the substrate 300, and the first electrode 150 and the second electrode 160 are electrically connected to the first active layer 110 through the first gate insulating layer 171.

[0125] The first gate insulating layer 171 serves to isolate and insulate the first active layer 110. The first electrode 150 and the second electrode 160 only need to pass through a layer of the first gate insulating layer 171 to be electrically connected to the first active layer 110. That is, only one more insulating layer needs to be opened, which makes the process simple and the production efficiency relatively high.

[0126] Since the first electrode 150 and the second electrode 160 are conductive, the first electrode 150 and the second electrode 160 are generally made of metal materials. If the sacrificial layer is made of metal materials, when the etching solution corrodes the sacrificial layer, the etching solution is likely to corrode the first electrode 150 and the second electrode 160 as well, affecting the use of the first electrode 150 and the second electrode 160.

[0127] To address this issue, the sensing transistor 100 further includes a first interlayer dielectric (ILD) 172 . The first interlayer dielectric 172 is disposed between the first gate insulating layer 171 and the first insulating layer 130 . The first interlayer dielectric 172 covers the first electrode 150 and the second electrode 160 . The first interlayer dielectric 172 and the first insulating layer 130 are close to each other on one side to form a cavity structure 10 , thereby ensuring the insulation of the cavity structure 10 .

[0128] In this way, the first interlayer insulating layer 172 can isolate and protect the first electrode 150 and the second electrode 160, and the etching solution will only corrode the sacrificial layer without corroding the first electrode 150 and the second electrode 160, thereby ensuring that the first electrode 150 and the second electrode 160 will not be affected during the formation of the cavity structure 10, thereby ensuring the reliability of the first electrode 150 and the second electrode 160.

[0129] In one embodiment, as shown in Figures 1, 4, and 10, the sensing transistor 100 further includes a second sensing gate 180. The second sensing gate 180 is disposed between the first active layer 110 and the substrate 300 and overlaps with the first active layer 110. The overlapping of the second sensing gate 180 with the first active layer 110 specifically means that the orthographic projection of the second sensing gate 180 on the substrate 300 at least partially overlaps with the orthographic projection of the first active layer 110 on the substrate 300.

[0130] The second sensing gate 180 can be used to independently control the sensing transistor 100 to operate in a certain initial state. When external pressure is applied to the first sensing gate 120, the capacitance between the first sensing gate 120 and the first active layer 110 changes, thereby changing the output current of the second electrode 160 in the sensing transistor 100. The combined action of the second sensing gate 180 and the first sensing gate 120 ensures operational stability and control flexibility of the sensing transistor 100 even when the first sensing gate 120 is subjected to pressure.

[0131] The first sensing gate 120 and the second sensing gate 180 can apply different driving voltages to provide different electrical driving signals, so as to facilitate more flexible control of the state of the sensing transistor 100; of course, the first sensing gate 120 and the second sensing gate 180 can also be connected together to apply one electrical driving signal.

[0132] The first sensing gate 120 and the second sensing gate 180 can be made of one of molybdenum, copper, aluminum, titanium and niobium, or a combination of two or more of the above.

[0133] In one embodiment, the sensing transistor 100 further includes a first buffer layer 190 . The first buffer layer 190 covers the second sensing gate 180 . The first active layer 110 is disposed on a surface of the first buffer layer 190 away from the substrate 300 .

[0134] The first buffer layer 190 is used to protect the thin film transistors, ensuring that the first active layer 110 is separated from the substrate 300, preventing impurities in the substrate 300 from affecting the thin film transistors, and ensuring that the thin film transistors can function properly. For example, the first buffer layer 190 can be a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer to ensure the insulation effect of the first buffer layer 190 and to separate the first active layer 110 from the substrate 300.

[0135] Among them, the first buffer layer 190, the first separation layer 131, the first planarizing layer 132, the first insulating covering layer 140, the first gate insulating layer 171 and the first interlayer insulating layer 172 can all be made of materials such as silicon nitride and silicon oxide; the first planarizing layer 132 and the first insulating covering layer 140 can also be made of organic polymer materials, for example, photoresist, or epoxy resins such as SU-8.

[0136] This embodiment also provides a pressure sensing panel, including the above-mentioned pressure sensor.

[0137] The pressure sensor provided in this embodiment includes the aforementioned pressure sensor. Different pressures applied to the first sensing gate 120 result in different output currents from the second electrode 160, thereby enabling detection of varying pressures. Because the capacitance change directly acts on the first sensing gate 120 of the sensing transistor 100, the voltage and current signals are converted and amplified, thereby improving the sensitivity of the pressure sensor.

[0138] In one embodiment, as shown in FIG11 , there are multiple sensing transistors 100, and the multiple pressure sensors are arranged in an array along row and column directions. The top gates of the sensing transistors 100 in the same column are connected via a scan line, the first electrodes 150 of the sensing transistors 100 in the same row are connected via a data line, and the second electrodes 160 of the sensing transistors 100 in the same row are connected via an output line. The row and column directions are two mutually intersecting and perpendicular directions, not specifically referring to vertical and horizontal directions. The row direction is indicated by an X, and the column direction is indicated by a Y.

[0139] Since one sensing transistor 100 corresponds to one pixel, multiple sensing transistors 100 are arranged in an array to form an array pixel. A scan line applies a top gate scan voltage to the top gate of the same column, and a data line applies a data voltage to the first electrodes 150 of the same row. Ultimately, the second electrodes 160 of each row output current through the data line.

[0140] It is understood that if the sensing transistors 100 include a second sensing gate 180, the bottom gates of the sensing transistors 100 in the same column are connected via a scan line. That is, the scan line can apply a bottom-gate scan voltage to the bottom gates in the same column. Of course, different scan voltages can be applied to the first sensing gate 120 and the second sensing gate 180 to provide different electrical drive signals, thereby facilitating more flexible control of the state of the sensing transistors 100.

[0141] As shown in FIG12 , this embodiment further provides a method for manufacturing a pressure sensor, which includes the following steps:

[0142] S1, forming a first active layer 110 on a substrate 300;

[0143] S2, forming a cavity structure 10 on a side of the first active layer 110 facing away from the substrate 300;

[0144] S3 . Form a first sensing gate 120 on a side of the cavity structure 10 facing away from the substrate 300 and overlapping with the cavity structure 10 .

[0145] The pressure sensor manufacturing method provided in this embodiment does not require changing the existing process flow or using complex special materials. It only requires forming a cavity structure 10 on the side of the first active layer 110 away from the substrate 300. While realizing the pressure sensor, it can also realize the function of pressure detection, and the production cost is relatively low.

[0146] In one embodiment, forming the cavity structure 10 on the side of the first active layer 110 facing away from the substrate 300 includes the following steps:

[0147] forming a second insulating layer 170 on a side of the first active layer 110 facing away from the substrate 300;

[0148] A sacrificial layer is formed on a side of the second insulating layer 170 facing away from the substrate 300 and overlapping with the first sensing gate 120 and the second insulating layer 170 ;

[0149] A first insulating layer 130 is formed on a side of the sacrificial layer facing away from the substrate 300 to cover the sacrificial layer;

[0150] The sacrificial layer is removed to form a cavity structure 10 between the first insulating layer 130 and the second insulating layer 170 .

[0151] In this manner, it is only necessary to determine the position of the sacrificial layer relative to the first sensing gate 120 and the second insulating layer 170, as well as the contour and shape of the sacrificial layer. After removing the sacrificial layer, a cavity structure 10 corresponding to the sacrificial layer is obtained. In other words, the position of the sacrificial layer corresponds to the position of the cavity structure 10, and the outer contour and shape of the sacrificial layer correspond to the inner contour and shape of the cavity structure 10. Furthermore, the first insulating layer 130 covers the sacrificial layer, and after removing the sacrificial layer, a closed cavity structure 10 is formed between the first insulating layer 130 and the second insulating layer 170.

[0152] In one embodiment, removing the sacrificial layer comprises the following steps:

[0153] A first separation layer 131 is formed on a side of the sacrificial layer facing away from the substrate 300;

[0154] forming a sacrificial etching hole 1311 on the first separation layer 131;

[0155] Passing an etching solution into the sacrificial etching hole 1311 to allow the etching solution to corrode the sacrificial layer, thereby forming a cavity structure 10 between the first separation layer 131 and the second insulating layer 170;

[0156] A first planarization layer 132 is formed on a side of the first separation layer 131 facing away from the substrate 300 to block the sacrificial etching hole 1311 .

[0157] When the sacrificial etchant passes through sacrificial etch hole 1311 and into the space between first spacer layer 131 and second insulating layer 170, it corrodes the sacrificial layer. As an underlying thin film, the sacrificial layer merely serves as a separation layer, thereby forming a cavity structure 10 between first spacer layer 131 and second insulating layer 170. During this process, the sacrificial layer does not corrode first spacer layer 131, thereby preventing damage to the internal microstructure of sensing transistor 100, thereby ensuring the reliability of sensing transistor 100. Because sacrificial etch hole 1311 serves as a process hole, the side of first planarizing layer 132 facing substrate 300 blocks sacrificial etch hole 1311, resulting in a closed cavity structure 10. Furthermore, the side of first planarizing layer 132 facing away from substrate 300 is flat, facilitating the formation and placement of first sensing gate 120.

[0158] It should be noted that although the steps of the pressure sensor manufacturing method disclosed herein are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all steps must be performed to achieve the desired results. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into a single step, and / or a single step may be broken down into multiple steps.

[0159] Example 2

[0160] This embodiment is similar to the first embodiment, and the only difference is the specific structure of the first insulating cover layer 140 .

[0161] As shown in FIG13 , the sensing transistor 100 further includes a pressing portion 20, which is disposed on a side of the first sensing gate 120 facing away from the substrate 300 and corresponding to the cavity structure 10. The pressing portion 20 effectively transmits external pressing force to the cavity structure 10, thereby facilitating deformation of the cavity structure 10.

[0162] In one embodiment, the pressing portion 20 is a protruding structure having a size of micrometers. The pressing portion 20 is specifically provided protrudingly on the side of the cover insulating layer away from the first sensing gate 120 to facilitate application of external pressure and force transmission.

[0163] In one embodiment, the orthographic projection shape of the protrusion structure on the substrate 300 may be a triangle, a circle, etc. There are many options for the shape, which is not limited in this embodiment.

[0164] In one embodiment, the protruding structure may be made of silicon nitride, silicon oxide, or an organic polymer material, but the protruding structure cannot be made of the same material as the first insulating capping layer 140 to ensure compatibility during the etching process.

[0165] Example 3

[0166] This embodiment is similar to the first embodiment, and the only difference is the number of cavities.

[0167] As shown in Figure 14, the pressure sensor provided by this embodiment has multiple cavity structures 10, and the multiple cavity structures 10 are arranged in parallel and spaced apart between the first active layer 110 and the first sensing gate 120. The orthographic projections of the multiple cavity structures 10 on the substrate 300 are located inside the orthographic projections of the first sensing gate 120 on the substrate 300.

[0168] Specifically, the cavity structure 10 may have other deformed structures. When there are multiple cavity structures 10, it is equivalent to dividing the larger cavity structure 10 into multiple smaller sub-cavities. The multiple cavity structures 10 correspond to the first sensing gate 120, which can withstand the pressing force applied to the first sensing gate 120, thereby improving the sensitivity of the pressure sensor.

[0169] Example 4

[0170] This embodiment is similar to the first embodiment, and the only difference is the structure of the pressure sensing panel.

[0171] As shown in FIG. 15 , the pressure sensing panel provided in this embodiment further includes a switch transistor 200 . The switch transistor 200 is disposed on the substrate 300 . The second electrode 160 of the sensing transistor 100 is connected to the output line through the switch transistor 200 .

[0172] In the pressure sensing panel provided in this embodiment, each pixel has two thin film transistors. The sensing transistor 100 has a cavity structure 10 and serves as a pressure sensing portion. The switching transistor 200 does not have a cavity structure 10 and only functions as a switch control.

[0173] In one embodiment, the switching transistor 200 further includes a third electrode 250 and a fourth electrode 260 . The second electrode 160 of the sensing transistor 100 is connected to the third electrode 250 of the switching transistor 200 . The fourth electrode 260 of the switching transistor 200 is connected to the output line. The gate of the switching transistor 200 is connected to the scan line.

[0174] The switching transistor 200 acts as a control switch, turning on and off at regular time intervals. When the scan line provides a gate scan signal to the switching transistor 200, the switching transistor 200 is turned on, and the output current in the sensing transistor 100 can be read by an external detection circuit. The external detection circuit can accurately determine the trigger signal sensed by the pressure sensor based on the change in the read current value.

[0175] In one embodiment, as shown in FIG16 , the switch transistor 200 includes a second active layer 210 and a first switch gate 220. The second active layer 210 is disposed on a substrate 300 and electrically connected to the first active layer 110. The first switch gate 220 is disposed on a side of the second active layer 210 facing away from the substrate 300. By utilizing the electrical connection between the first active layer 110 and the second active layer 210, the switch transistor 200 can control the sensing transistor 100.

[0176] Specifically, the second active layer 210 is provided on the same layer as the first active layer 110, and the first switch gate 220 is provided on the same layer as the first sensing gate 120. The term "provided on the same layer" specifically refers to different regions of the same film layer being made of the same material and being formed simultaneously through the same patterning process, thereby simplifying the manufacturing process and improving production efficiency.

[0177] In one embodiment, as shown in FIG. 16 , the switch transistor 200 further includes a second switch gate 280 , a second buffer layer 290 , a second gate insulating layer 271 , a second interlayer insulating layer 272 , a second separation layer 231 , a second planarization layer 232 and a second insulating capping layer 240 .

[0178] The second switch gate 280, the second buffer layer 290, the second active layer 210, the second gate insulating layer 271, the third electrode 250, the fourth electrode 260, the second interlayer insulating layer 272, the second spacer layer 231, the second planarizing layer 232, the second gate insulating layer 271, and the second insulating cover layer 240 are stacked in sequence. Except for the cavity structure 10, the other layers between the sensing transistor 100 and the switching transistor 200 are correspondingly arranged. The other layers can be arranged in the same layer or in different layers.

[0179] It should be noted that the switch transistor 200 provided in this embodiment may also include only the first switch gate 220 without the second switch gate 280. Of course, the first switch gate 220 may also be located between the second gate insulating layer 271 and the second interlayer insulating layer 272, or between the second gate insulating layer 271 and the second spacer layer 231, or between the second spacer layer 231 and the second planarizing layer 232.

[0180] It should be noted that this embodiment does not limit the location of the first electrode 150, the second electrode 160, the third electrode 250 and the fourth electrode 260. Each electrode is not necessarily arranged between the corresponding gate insulation layer and the interlayer insulation layer, but can also be arranged between other adjacent insulation layers.

[0181] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A pressure sensor, characterized in that: The invention comprises a substrate and a sensing transistor, wherein the sensing transistor comprises: A first active layer is disposed on the substrate; A first sensing gate is arranged on a side of the first active layer away from the substrate; The cavity structure is disposed between the first active layer and the first sensing gate and overlaps with the first sensing gate.

2. The pressure sensor according to claim 1, characterized in that: The sensing transistor further comprises: A first insulating layer, disposed between the first active layer and the first sensing gate and overlapping with the cavity structure; A second insulating layer, covering the first active layer and overlapping the cavity structure; Wherein, at least part of the cavity structure is arranged inside at least one of the first insulating layer and the second insulating layer.

3. The pressure sensor according to claim 2, characterized in that: The first insulating layer comprises: A first separation layer, disposed between the first active layer and the first sensing gate; The first separation layer is provided with a sacrificial etching hole, the sacrificial etching hole is connected with the cavity structure, and the cavity structure is provided in the first separation layer.

4. The pressure sensor according to claim 3, characterized in that: The first separation layer comprises: A body portion, disposed between the first active layer and the first sensing gate; The protrusion is protrudingly arranged on a side of the main body away from the substrate, the sacrificial etching hole is arranged on the protrusion, and the protrusion and the second insulating layer surround the cavity structure.

5. The pressure sensor according to claim 3, characterized in that: The orthographic projection of the sacrificial etching hole on the substrate is located outside the orthographic projection of the first active layer on the substrate.

6. The pressure sensor according to claim 3, characterized in that: The first insulating layer further comprises: The first planar layer is disposed between the first separation layer and the first sensing gate and can block the sacrificial etching hole.

7. The pressure sensor according to claim 2, characterized in that: The sensing transistor further comprises: The first insulating covering layer is arranged on a side of the first insulating layer away from the substrate, and the first insulating covering layer covers the first sensing gate.

8. The pressure sensor according to claim 2, characterized in that: The sensing transistor further comprises: The first electrode and the second electrode are disposed on a surface of the second insulating layer facing the substrate and are electrically connected to the via hole of the first active layer.

9. The pressure sensor according to claim 8, characterized in that: The second insulating layer comprises: A first gate insulating layer is disposed on a side of the first active layer away from the substrate, and the first electrode and The second electrode is electrically connected to the first active layer through the first gate insulating layer; The first interlayer insulating layer is disposed between the first gate insulating layer and the first insulating layer, the first interlayer insulating layer covers the first electrode and the second electrode, and the first interlayer insulating layer and the first insulating layer are close to each other on one side to form the cavity structure.

10. The pressure sensor according to claim 1, characterized in that: The sensing transistor further comprises: A second sensing gate is disposed between the first active layer and the substrate and overlaps the first active layer; The first buffer layer covers the second sensing gate, and the first active layer is arranged on a surface of the first buffer layer away from the substrate.

11. The pressure sensor according to any one of claims 1 to 10, characterized in that: The orthographic projection of the cavity structure on the substrate is located inside the orthographic projection of the first active layer on the substrate.

12. The pressure sensor according to any one of claims 1 to 10, characterized in that: The boundary of the orthographic projection of the cavity structure on the substrate is located inside the boundary of the orthographic projection of the first sensing gate on the substrate.

13. The pressure sensor according to any one of claims 1 to 10, characterized in that: The projection of the cavity structure relative to the substrate is a circular structure.

14. The pressure sensor according to any one of claims 1 to 10, characterized in that: The cavity structure is filled with gas; or, The cavity structure is a vacuum structure.

15. The pressure sensor according to any one of claims 1 to 10, characterized in that: The sensing transistor further comprises: The pressing portion is arranged on a side of the first sensing grid away from the substrate and is arranged corresponding to the cavity structure.

16. The pressure sensor according to any one of claims 1 to 10, characterized in that: There are multiple cavity structures, and the multiple cavity structures are arranged in parallel and spaced apart between the first active layer and the first sensing gate. The orthographic projections of the multiple cavity structures on the substrate are located inside the orthographic projections of the first sensing gate on the substrate.

17. A pressure sensing panel, characterized in that: A pressure sensor comprising any one of claims 1-16.

18. The pressure sensing panel according to claim 17, characterized in that: There are multiple pressure sensors, which are arranged in an array along row and column directions. The top gates of the sensing transistors in the same column are connected through a scan line, the first electrodes of the sensing transistors in the same row are connected through a data line, and the second electrodes of the sensing transistors in the same row are connected through an output line.

19. The pressure sensing panel according to claim 18, characterized in that: The pressure sensing panel also includes: A switch transistor is disposed on the substrate, and the second electrode of the sensing transistor is connected to the switch transistor. connected to the output line.

20. The pressure sensing panel according to claim 19, characterized in that: The switching transistor comprises: a second active layer, disposed on the substrate, the second active layer being electrically connected to the first active layer and disposed on the same layer as the first active layer; The first switch gate is arranged on a side of the second active layer away from the substrate and is arranged in the same layer as the first sensing gate.

Images