Pressure sensor and preparation method thereof

Abstract

The invention discloses a pressure sensor and a pressure sensor preparation method, and the pressure sensor comprises a first flexible substrate layer; the wiring layer is arranged on one side of the first flexible substrate layer; the first insulating layer comprises a via hole; the electrode layer is arranged on the side, away from the first flexible substrate layer, of the first insulating layer, the electrode layer comprises a pressure-sensitive electrode, and the pressure-sensitive electrode is electrically connected with the wiring layer through a via hole; the pressure-sensitive layer is arranged on the side, away from the first flexible substrate layer, of the electrode layer, the orthographic projection of the pressure-sensitive layer on the first flexible substrate layer and the orthographic projection of the pressure-sensitive electrode on the first flexible substrate layer at least partially coincide, the pressure-sensitive layer and the first insulating layer are connected through a bonding part, and a cavity structure is defined by the pressure-sensitive layer, the electrode layer and the bonding part; the second flexible substrate layer is arranged on the side, away from the first flexible substrate layer, of the pressure-sensitive layer. The stability and the use performance of the pressure sensor are effectively improved, large-area preparation of the flexible pressure sensor is facilitated, and the mass production feasibility is improved.

Description

Technical Field

[0001] The present application belongs to the field of sensor technology, and in particular relates to a pressure sensor and a method for preparing the pressure sensor. Background Art

[0002] A pressure sensor is a device that senses pressure in the vertical direction. There are various types based on the principle of sensing pressure. Examples include piezoresistive pressure sensors, piezoelectric pressure sensors, capacitive pressure sensors, and fabric pressure sensors.

[0003] However, the performance of current pressure sensors needs to be improved.

[0004] Therefore, a new pressure sensor and a method for preparing the pressure sensor are urgently needed. Summary of the invention

[0005] The embodiments of the present application provide a pressure sensor and a method for preparing the pressure sensor. A first flexible substrate layer and a second flexible substrate layer are prepared using a flexible material to improve the bending performance of the pressure sensor and the degree of fit with other structures with large curvature. A first insulating layer including vias is provided between the electrode layer and the wiring layer. While realizing signal connection between the electrode layer and the wiring layer, electrical insulation between the two (non-via areas) is ensured, thereby effectively improving the stability and performance of the pressure sensor, facilitating large-area preparation of flexible pressure sensors, and improving the feasibility of mass production.

[0006] On the one hand, an embodiment of the present application provides a pressure sensor, including: a first flexible substrate layer; a routing layer, arranged on one side of the first flexible substrate layer; a first insulating layer, arranged on a side of the routing layer away from the first flexible substrate layer, the first insulating layer including a via; an electrode layer, arranged on a side of the first insulating layer away from the first flexible substrate layer, the electrode layer including a pressure-sensing electrode, the pressure-sensing electrode being electrically connected to the routing layer through the via; a pressure-sensitive layer, arranged on a side of the electrode layer away from the first flexible substrate layer, the orthographic projection of the pressure-sensitive layer on the first flexible substrate layer and the orthographic projection of the pressure-sensing electrode on the first flexible substrate layer at least partially overlapping, the pressure-sensitive layer and the first insulating layer are connected by an adhesive portion, the pressure-sensitive layer, the electrode layer, and the adhesive portion forming a cavity structure; a second flexible substrate layer, arranged on a side of the pressure-sensitive layer away from the first flexible substrate layer.

[0007] According to one aspect of the present application, it also includes an insulating part, which is arranged between the bonding part and the first insulating layer; preferably, the thickness of the insulating part is greater than or equal to the thickness of the electrode layer; preferably, the thickness of the insulating part is greater than or equal to 0.2μm, and less than or equal to 1.2μm; preferably, the thickness of the electrode layer is greater than or equal to 0.2μm, and less than or equal to 1.2μm; preferably, the thickness of the routing layer is greater than or equal to 0.2μm, and less than or equal to 1.2μm; preferably, the thickness of the first insulating layer is greater than or equal to 0.2μm, and less than or equal to 0.6μm.

[0008] According to one aspect of the present application, it also includes a second insulating layer, which is arranged between the first flexible substrate layer and the routing layer, and the thickness of the second insulating layer is greater than or equal to 0.1μm and less than or equal to 2μm; preferably, the first insulating layer and the second insulating layer are made of the same material; preferably, the first insulating layer and the second insulating layer both include inorganic materials; preferably, the first insulating layer and the second insulating layer both include at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0009] According to one aspect of the present application, the second flexible substrate layer and the first flexible substrate layer are made of the same material; preferably, the first flexible substrate layer and the second flexible substrate layer include insulating material; preferably, the first flexible substrate layer and the second flexible substrate layer both include polyimide and polyethylene terephthalate; preferably, the thickness of the first flexible substrate layer and the second flexible substrate layer are both greater than or equal to 5 μm and less than or equal to 20 μm.

[0010] According to one aspect of the present application, the electrode layer includes a first electrode structure and a second electrode structure insulated from each other, the first electrode structure includes a plurality of first electrode blocks arranged and electrically connected along a first direction, the plurality of first electrode structures are arranged at intervals along a second direction, the second electrode structure includes a plurality of second electrode blocks arranged and electrically connected along the second direction, the plurality of second electrode structures are arranged at intervals along the first direction, and the first direction and the second direction intersect.

[0011] On the other hand, the present invention also provides a method for preparing a pressure sensor, comprising the following steps: providing a first flexible substrate layer; forming a routing layer on one side of the first flexible substrate layer; forming a first insulating layer on the side of the routing layer away from the first flexible substrate layer, the first insulating layer comprising a via; forming an electrode layer on the side of the first insulating layer away from the first flexible substrate layer, the electrode layer comprising a pressure-sensing electrode, the pressure-sensing electrode being electrically connected to the routing layer through the via; providing a second flexible substrate layer, and sequentially forming a pressure-sensitive layer and an adhesive portion provided on one side of the pressure-sensitive layer on one side of the second flexible substrate layer; placing the pressure-sensitive layer on the side of the electrode layer away from the first flexible substrate layer, so that the pressure-sensitive layer and the first insulating layer are connected through the adhesive portion, the orthographic projection of the pressure-sensitive layer on the first flexible substrate layer and the orthographic projection of the pressure-sensing electrode on the first flexible substrate layer at least partially overlap, and the pressure-sensitive layer, the electrode layer, and the adhesive portion form a cavity structure.

[0012] According to another aspect of the present application, the step of providing a first flexible substrate layer includes: providing a first glass substrate; forming the first flexible substrate layer on one side of the first glass substrate through a coating process; forming an electrode layer on the side of the first insulating layer facing away from the first flexible substrate layer and the step of providing a pressure-sensitive layer and an adhesive portion provided on one side of the pressure-sensitive layer also includes: forming an insulating portion on the side of the first insulating layer facing away from the first flexible substrate layer; and separating the first glass substrate and the first flexible substrate layer through a laser lift-off process.

[0013] According to another aspect of the present application, the step of providing a pressure-sensitive layer and a bonding portion provided on one side of the pressure-sensitive layer includes: providing a second glass substrate, and sequentially forming the second flexible substrate layer, the pressure-sensitive layer and the bonding portion on one side of the second glass substrate; separating the second glass substrate and the second flexible substrate layer by a laser lift-off process; and placing the pressure-sensitive layer on the side of the electrode layer away from the first flexible substrate layer, so that the pressure-sensitive layer and the insulating portion are connected through the bonding portion.

[0014] According to another aspect of the present application, in the step of forming a first insulating layer on the side of the routing layer away from the first flexible substrate layer, the step includes forming a first insulating material layer on the side of the routing layer away from the first flexible substrate layer by chemical vapor deposition or coating process; patterning the first insulating material layer by photolithography process to form the first insulating layer including vias; preferably, the photolithography process includes the following steps: coating photoresist on one side of the first insulating material layer; exposing part of the photoresist using a patterned mask; removing the exposed part of the photoresist to form a patterned photoresist; etching the first insulating material layer not covered by the photoresist to form the vias; and stripping the photoresist.

[0015] According to another aspect of the present application, the step of forming a routing layer on one side of the first flexible substrate layer includes: forming a whole layer of a first metal material layer on one side of the first flexible substrate layer by physical vapor deposition; patterning the first metal material layer by a photolithography process to form the routing layer; and / or, the step of forming an electrode layer on the side of the first insulating layer away from the first flexible substrate layer includes: forming a whole layer of a second metal material layer on the side of the first insulating layer away from the first flexible substrate layer by physical vapor deposition; patterning the second metal material layer by a photolithography process to form the electrode layer.

[0016] Compared with the prior art, the pressure sensor provided in the embodiment of the present invention includes a first flexible substrate layer, a wiring layer, a first insulating layer, an electrode layer, a pressure-sensitive layer, an adhesive portion and a second flexible substrate layer. The pressure sensor causes the pressure-sensitive layer to deform under stress, thereby causing the pressure-sensitive layer to press down in the cavity structure and come into contact with the electrode layer, so that the resistance of a specific channel is reduced; the greater the pressure, the greater the contact area between the pressure-sensitive layer and the electrode layer, and the greater the resistance reduction, thereby sensing the magnitude of the pressure, and sensing the position of the pressure by scanning the row and column scanning to detect the position of the resistance change. In the embodiment of the present invention, the first flexible substrate layer and the second flexible substrate layer are prepared by using flexible materials to improve the bending performance of the pressure sensor and the degree of fit with other large curvature structures, and a first insulating layer including vias is provided between the electrode layer and the wiring layer, while realizing the signal connection between the electrode layer and the wiring layer, the electrical insulation of the two (non-via area) is ensured, which effectively improves the stability and performance of the pressure sensor, is conducive to the large-area preparation of flexible pressure sensors, and improves the feasibility of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a schematic diagram of the structure of a pressure sensor provided by an embodiment of the present invention;

[0019] Figure 2 An embodiment provides Figure 1 Schematic diagram of the cross-sectional structure at AA in the middle;

[0020] Figure 3 is a flow chart of a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0021] Figure 4 is a cross-sectional schematic diagram of a structure obtained in step S110 in a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0022] Figure 5 is a cross-sectional schematic diagram of a structure obtained in step S120 in a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0023] Figure 6 is a cross-sectional schematic diagram of a structure obtained in step S130 in a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0024] Figure 7 is a schematic cross-sectional view of a structure obtained in step S140 in a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0025] Figure 8 is a cross-sectional schematic diagram of a structure obtained in step S150 in a method for preparing a pressure sensor provided by an embodiment of the present invention;

[0026] Fig. 9 is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by an embodiment of the present invention;

[0027] Fig.10 is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by another embodiment of the present invention;

[0028] Fig.11 is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by another embodiment of the present invention;

[0029] Fig.12is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by another embodiment of the present invention;

[0030] Fig.13 is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by another embodiment of the present invention;

[0031] Fig.14 It is a cross-sectional schematic diagram of a structure obtained during the preparation process of a pressure sensor preparation method provided by another embodiment of the present invention.

[0032] In the attached figure:

[0033] 1-first flexible substrate layer; 2-wiring layer; 2'-first metal material layer; 3-first insulating layer; 4-electrode layer; 5-pressure-sensitive layer; 6-second flexible substrate layer; 7-adhesive part; 8-insulating part; 9-second insulating layer; K-cavity structure. DETAILED DESCRIPTION

[0034] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0036] It should be understood that when describing the structure of a component, when a layer or a region is referred to as being "on" or "over" another layer or another region, it may mean that it is directly on the other layer or another region, or that other layers or regions are included between it and the other layer or another region. Moreover, if the component is turned over, the layer or a region will be "below" or "beneath" another layer or another region.

[0037] It is obvious to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit or scope of the present application. Therefore, the present application is intended to cover modifications and changes of the present application that fall within the scope of the corresponding claims (technical solutions for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0038] The present application provides a pressure sensor and a method for preparing the pressure sensor. Figures 1 to 14 Various embodiments of a pressure sensor and a method for manufacturing the pressure sensor are described.

[0039] See also Figure 1 to Figure 2 A pressure sensor provided in an embodiment of the present application includes: a first flexible substrate layer 1; a wiring layer 2, which is arranged on one side of the first flexible substrate layer 1; a first insulating layer 3, which is arranged on the side of the wiring layer 2 away from the first flexible substrate layer 1, and the first insulating layer 3 includes a via hole; an electrode layer 4, which is arranged on the side of the first insulating layer 3 away from the first flexible substrate layer 1, and the electrode layer 4 includes a pressure sensing electrode, and the pressure sensing electrode is electrically connected to the wiring layer 2 through the via hole; a pressure-sensitive layer 5, which is arranged on the side of the electrode layer 4 away from the first flexible substrate layer 1, and the orthographic projection of the pressure-sensitive layer 5 on the first flexible substrate layer 1 and the orthographic projection of the pressure-sensitive electrode on the first flexible substrate layer 1 at least partially overlap, the pressure-sensitive layer 5 and the first insulating layer 3 are connected by an adhesive portion 7, and the pressure-sensitive layer 5, the electrode layer 4, and the adhesive portion 7 surround a cavity structure K; a second flexible substrate layer 6, which is arranged on the side of the pressure-sensitive layer 5 away from the first flexible substrate layer 1.

[0040] The pressure sensor provided by the embodiment of the present invention includes a first flexible substrate layer 1, a wiring layer 2, a first insulating layer 3, an electrode layer 4, a pressure-sensitive layer, an adhesive portion 7 and a second flexible substrate layer 6. The pressure sensor causes the pressure-sensitive layer 5 to deform under stress, thereby causing the pressure-sensitive layer 5 to press down in the cavity structure K and come into contact with the electrode layer 4, so that the resistance of a specific channel is reduced; the greater the pressure, the greater the contact area between the pressure-sensitive layer 5 and the electrode layer 4, and the greater the resistance reduction, thereby sensing the magnitude of the pressure, and sensing the position of the pressure by scanning the position where the resistance changes through row and column scanning. In the embodiment of the present invention, the first flexible substrate layer 1 and the second flexible substrate layer 6 are prepared by using flexible materials to improve the bending performance of the pressure sensor and the degree of fit with other large curvature structures, and a first insulating layer 3 including a via is provided between the electrode layer 4 and the wiring layer 2, while realizing the signal connection between the electrode layer 4 and the wiring layer 2, ensuring the electrical insulation of the two (non-via area), effectively improving the stability and performance of the pressure sensor, and being conducive to realizing the large-area preparation of flexible pressure sensors and improving the feasibility of mass production.

[0041] In this embodiment, the bonding portion 7 plays the role of bonding the pressure-sensitive layer 5 and the first insulating layer 3, and on the other hand, the thickness of the bonding portion 7 itself can also be used to increase the depth of the cavity structure K, so that the pressure-sensitive layer can maintain a certain distance from the electrode layer 4 when not under pressure, so as to ensure the accuracy of pressure detection.

[0042] Optionally, the material of the adhesive portion 7 may include OCA (Optically Clear Adhesive) glue, UV (Ultraviolet Rays) glue, pressure-sensitive adhesive, etc.

[0043] Optionally, the pressure-sensitive layer 5 is a functional layer that responds to pressure, and the material of the pressure-sensitive layer 5 may include carbon-based nanomaterials such as carbon tubes, graphene, carbon black, or other non-transparent / transparent pressure-sensitive materials.

[0044] Optionally, the first flexible substrate layer 1 and the second flexible substrate layer 6 are substrates for the electrode layer 4 and the pressure sensing layer, and the first flexible substrate layer 1 and the second flexible substrate layer 6 may include insulating materials.

[0045] For example, the materials of the first flexible substrate layer 1 and the second flexible substrate layer 6 can both include at least one of polyimide (PI), polyethylene terephthalate (PET), and polyurethane (PU). The first flexible substrate layer 1 and the second flexible substrate layer 6 can adopt a single-layer material structure, or can adopt a multi-layer laminated material structure. For example, the first flexible substrate layer 1 and the second flexible substrate layer 6 can be composed of multi-layer laminated insulating materials such as polyimide / silicon nitride / amorphous silicon.

[0046] The first flexible substrate layer 1 and the second flexible substrate layer 6 can be prepared by a coating process, or by a coating process + CVD (Chemical Vapor Deposition) process to produce a laminated structure of polyimide / silicon nitride / amorphous silicon, etc., to prevent impurities and water vapor from penetrating.

[0047] Optionally, the thickness of the first flexible substrate layer 1 and the second flexible substrate layer 6 is greater than or equal to 5 μm and less than or equal to 20 μm. For example, the thickness of the first flexible substrate layer 1 and the second flexible substrate layer 6 can be equal to any one of 5 μm, 10 μm, 15 μm, and 20 μm. Compared with the hard glass substrate in the prior art, the first flexible substrate layer 1 and the second flexible substrate layer 6 in the embodiment of the present invention have better bending performance and a small thickness, which can effectively reduce the overall thickness of the pressure sensor.

[0048] Optionally, the second flexible substrate layer 6 and the first flexible substrate layer 1 are made of the same material, so that the second flexible substrate layer 6 and the first flexible substrate layer 1 can be prepared by the same process, thereby reducing the process cost.

[0049] In some optional embodiments, the routing layer 2 may include patterned signal lines, which may be used as bridge connecting lines between electrode structures in the electrode layer 4 and leads between the electrode structures and the driving chip. The material of the routing layer 2 may include at least one of copper, silver, aluminum, and molybdenum, that is, the material of the routing layer 2 may be a metal element, an alloy, or a metal laminate structure. For example, the routing layer 2 may include titanium, aluminum, a titanium laminate structure, a copper-nickel alloy, or molybdenum, aluminum, and a molybdenum laminate structure.

[0050] When preparing the wiring layer 2, the entire surface of the metal material can be sputtered by a PVD (Physical Vapor Deposition) process, and then the entire surface of the metal material can be patterned by a photolithography process, which can specifically include the steps of photoresist coating → exposure → development → etching → stripping to form the desired wiring layer 2 pattern.

[0051] Optionally, the thickness of the routing layer 2 is greater than or equal to 0.2 μm and less than or equal to 1.2 μm. For example, the thickness of the routing layer 2 may be any one of 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, and 1.2 μm.

[0052] In some optional embodiments, the electrode layer 4 includes a first electrode structure and a second electrode structure insulated from each other, the first electrode structure includes a plurality of first electrode blocks arranged and electrically connected along a first direction, the plurality of first electrode structures are arranged at intervals along a second direction, the second electrode structure includes a plurality of second electrode blocks arranged and electrically connected along a second direction, the plurality of second electrode structures are arranged at intervals along the first direction, and the first direction and the second direction intersect.

[0053] It can be understood that in this embodiment, the first electrode structure and the second electrode structure are arranged along the first direction and the second direction respectively to respectively detect and determine the specific position of the pressed part along the first direction and the second direction. Optionally, the first electrode blocks arranged along the first direction can be connected by a bridge portion, and the bridge portion is provided in the routing layer 2.

[0054] Optionally, the material of the electrode layer 4 may include at least one of copper, silver, aluminum, and molybdenum, that is, the material of the electrode layer 4 may be a metal element, or an alloy or a metal stacked structure. For example, the electrode layer 4 may include titanium, aluminum, a titanium stacked structure, a copper-nickel alloy, or molybdenum, aluminum, and a molybdenum stacked structure.

[0055] Optionally, the electrode layer 4 can be prepared using the same process flow as the wiring layer 2 to reduce costs and facilitate preparation. When preparing the electrode layer 4, the entire surface of the metal material can be sputtered by a PVD (Physical Vapor Deposition) process, and then the entire surface of the metal material is patterned by a photolithography process, which can specifically include the steps of photoresist coating → exposure → development → etching → stripping to form the desired electrode layer 4 pattern, for example, the above-mentioned patterned first electrode structure and second electrode structure can be formed.

[0056] Optionally, the thickness of the electrode layer 4 is greater than or equal to 0.2 μm and less than or equal to 1.2 μm. For example, the thickness of the electrode layer 4 may be any one of 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, and 1.2 μm.

[0057] See also Figure 2 In some optional embodiments, the pressure sensor further includes an insulating portion 8 , which is disposed between the bonding portion 7 and the first insulating layer 3 .

[0058] It should be noted that the insulating part 8 is used to cover the non-metallic area at the edge of the electrode layer 4 to prevent short circuit between metals. The insulating part 8 may be made of insulating inorganic or organic materials. For example, the material of the insulating part 8 may include at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0059] Optionally, the thickness of the insulating portion 8 is greater than or equal to the thickness of the electrode layer 4 to ensure that the gap between the varistor layer 5 and the electrode layer 4 is large enough.

[0060] Optionally, the thickness of the insulating portion 8 is greater than or equal to 0.2 μm and less than or equal to 1.2 μm. For example, the thickness of the insulating portion 8 may be any one of 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, and 1.2 μm.

[0061] See also Figure 2 In some optional embodiments, the pressure sensor further includes a second insulating layer 9, which is disposed between the first flexible substrate layer 1 and the wiring layer 2, and a thickness of the second insulating layer 9 is greater than or equal to 0.1 μm and less than or equal to 2 μm.

[0062] In this embodiment, the second insulating layer 9 can cover the metal area of ​​the wiring layer 2 to prevent short circuits between wirings and isolate pollutants on the surface of the first flexible substrate layer 1 .

[0063] Optionally, the first insulating layer 3 and the second insulating layer 9 are made of the same material to reduce production costs and facilitate preparation. The first insulating layer 3 and the second insulating layer 9 both include insulating inorganic materials or organic materials, for example, the first insulating layer 3 and the second insulating layer 9 both include at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0064] Optionally, the thickness of the first insulating layer 3 is greater than or equal to 0.2 μm and less than or equal to 0.6 μm. For example, the thickness of the first insulating layer 3 may be any one of 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, and 0.6 μm.

[0065] Optionally, the thickness of the second insulating layer 9 is greater than or equal to 0.1 μm and less than or equal to 2 μm. For example, the thickness of the second insulating layer 9 may be any one of 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, and 2 μm.

[0066] The first insulating layer 3 and the second insulating layer 9 can be prepared using the following preparation process: silicon nitride, silicon oxide or a combination of the two materials can be deposited on the entire surface using a CVD process; then the insulating material is patterned using a photolithography process (including steps such as photoresist coating → exposure → development → etching → stripping) to form the first insulating layer 3 and the second insulating layer 9 of the desired pattern.

[0067] Alternatively, the first insulating layer 3 and the second insulating layer 9 may also be prepared by a coating process such as coating an organic film.

[0068] Since the electrode layer 4 and the insulating layer of the existing pressure sensor are usually prepared based on the FPC process; therefore, there are problems such as the thickness of each layer of the sensor is relatively thick, the bending performance is poor, the sensing accuracy and resolution are low, it is difficult to manufacture on a large area, and it is difficult to fit well with structures such as the human body surface / fingertips with large curvature.

[0069] See also Figure 3 In order to solve the above problems, an embodiment of the present invention further provides a method for preparing a pressure sensor, comprising the following steps:

[0070] S110: Provide a first flexible substrate layer 1, such as Figure 4 As shown;

[0071] S120: forming a wiring layer 2 on one side of the first flexible substrate layer 1, such as Figure 5 As shown;

[0072] S130: forming a first insulating layer 3 on the side of the wiring layer 2 away from the first flexible substrate layer 1, wherein the first insulating layer 3 includes vias, such as Figure 6 As shown;

[0073] S140: forming an electrode layer 4 on a side of the first insulating layer 3 away from the first flexible substrate layer 1, wherein the electrode layer 4 includes a pressure sensing electrode, and the pressure sensing electrode is electrically connected to the wiring layer 2 through a via hole, such as Figure 7 As shown;

[0074] S150: providing a second flexible substrate layer 6, and sequentially forming a pressure-sensitive layer 5 and an adhesive portion 7 disposed on one side of the pressure-sensitive layer 5 on one side of the second flexible substrate layer 6, such as Figure 8 As shown;

[0075] S160: placing the pressure-sensitive layer 5 on the side of the electrode layer 4 away from the first flexible substrate layer 1, so that the pressure-sensitive layer 5 and the first insulating layer 3 are connected via the bonding portion 7, the orthographic projection of the pressure-sensitive layer 5 on the first flexible substrate layer 1 and the orthographic projection of the pressure-sensitive electrode on the first flexible substrate layer 1 at least partially overlap, and the pressure-sensitive layer 5, the electrode layer 4, and the bonding portion 7 form a cavity structure K, such as Figure 2 shown.

[0076] The pressure sensor preparation method provided in the embodiment of the present invention prepares the first flexible substrate layer 1 and the second flexible substrate layer 6 respectively to form a laminated structure including the first flexible substrate layer 1, the wiring layer 2, the first insulating layer 3 and the electrode layer 4, and a laminated structure including the second flexible substrate layer 6, the pressure-sensitive layer 5, and the bonding portion 7, and the two are bonded by the bonding portion 7 to form the desired pressure sensor preparation method. The preparation process is simple and easy to implement, which is conducive to the large-area preparation of flexible pressure sensors and improves the feasibility of mass production.

[0077] In this embodiment, a first flexible substrate layer 1 and a second flexible substrate layer 6 are prepared by using a flexible material to improve the bending performance of the pressure sensor and the degree of fit with other structures with large curvature, and a first insulating layer 3 including vias is arranged between the electrode layer 4 and the wiring layer 2 to ensure electrical insulation between the electrode layer 4 and the wiring layer 2 (non-via area) while realizing signal connection between the electrode layer 4 and the wiring layer 2.

[0078] In step S110, a coating process may be used to prepare the first flexible substrate layer 1, or a coating process + CVD (Chemical Vapor Deposition) process may be used to prepare a laminated structure of polyimide / silicon nitride / amorphous silicon, etc., to prevent impurities and water vapor from penetrating.

[0079] The material of the first flexible substrate layer 1 may include at least one of polyimide (PI), polyethylene terephthalate (PET), and polyurethane (PU). The first flexible substrate layer 1 may adopt a single-layer material structure, or may adopt a multi-layer laminated material structure. For example, the first flexible substrate layer 1 and the second flexible substrate layer 6 may be composed of multi-layer laminated insulating materials such as polyimide / silicon nitride / amorphous silicon.

[0080] In step S120, when preparing the wiring layer 2, the entire surface of the metal material can be sputtered by a PVD (Physical Vapor Deposition) process, and then the entire surface of the metal material is patterned by a photolithography process, which can specifically include the steps of photoresist coating → exposure → development → etching → stripping to form the desired wiring layer 2 pattern.

[0081] The material of the routing layer 2 may include at least one of copper, silver, aluminum, and molybdenum, that is, the material of the routing layer 2 may be a single metal, or an alloy, or a metal laminate structure. For example, the routing layer 2 may include titanium, aluminum, a titanium laminate structure, a copper-nickel alloy, or molybdenum, aluminum, and a molybdenum laminate structure.

[0082] In step S130, the first insulating layer 3 can be prepared using the following preparation process: silicon nitride, silicon oxide or a combination of the two materials can be deposited on the entire surface using a CVD process; then the insulating material is patterned using a photolithography process (including steps such as photoresist coating → exposure → development → etching → stripping) to form a first insulating layer 3 with a desired pattern.

[0083] Alternatively, the first insulating layer 3 may also be prepared by a coating process such as coating an organic film.

[0084] In step S140, the electrode layer 4 can be prepared using the same process flow as the wiring layer 2 to reduce costs and facilitate preparation. When preparing the electrode layer 4, the entire surface of the metal material can be sputtered by a PVD (Physical Vapor Deposition) process, and then the entire surface of the metal material is patterned by a photolithography process, which can specifically include the steps of photoresist coating → exposure → development → etching → stripping to form the desired pattern of the electrode layer 4, for example, the above-mentioned patterned first electrode structure and second electrode structure can be formed.

[0085] Optionally, the material of the electrode layer 4 may include at least one of copper, silver, aluminum, and molybdenum, that is, the material of the electrode layer 4 may be a metal element, or an alloy or a metal stacked structure. For example, the electrode layer 4 may include titanium, aluminum, a titanium stacked structure, a copper-nickel alloy, or molybdenum, aluminum, and a molybdenum stacked structure.

[0086] In step S150, the pressure-sensitive layer 5 can be made of carbon-based nanomaterials such as carbon tubes, graphene, carbon black, or other non-transparent / transparent pressure-sensitive materials. The adhesive portion 7 is prepared by a dispensing process or a laminating process, and the material of the adhesive portion 7 can include OCA (Optically Clear Adhesive, optical glue) glue, UV (Ultraviolet Rays, ultraviolet light curing glue) glue, pressure-sensitive adhesive, etc.

[0087] In step S160, a laminated structure including a first flexible substrate layer 1, a wiring layer 2, a first insulating layer 3 and an electrode layer 4 and a laminated structure including a second flexible substrate layer 6, a pressure-sensitive layer 5 and an adhesive portion 7 can be bonded together through the adhesive portion 7, and the orthographic projection of the pressure-sensitive layer 5 on the first flexible substrate layer 1 and the orthographic projection of the pressure-sensing electrode on the first flexible substrate layer 1 at least partially overlap, that is, when under pressure, the pressure-sensitive layer 5 can be deformed due to external pressure and pressed against the electrode layer 4, thereby determining the pressure position.

[0088] In some optional embodiments, the step of providing the first flexible substrate layer 1 includes: providing a first glass substrate; forming the first flexible substrate layer 1 on one side of the first glass substrate by a coating process; between the steps of forming the electrode layer 4 on the side of the first insulating layer 3 away from the first flexible substrate layer 1 and providing the pressure-sensitive layer 5 and the bonding portion 7 provided on one side of the pressure-sensitive layer 5, the step also includes: forming an insulating portion 8 on the side of the first insulating layer 3 away from the first flexible substrate layer 1, such as Fig. 9 As shown; the first glass substrate and the first flexible substrate layer 1 are separated by a laser lift-off process, as shown Fig.10 shown.

[0089] In this embodiment, a laser lift-off process is adopted, that is, laser is irradiated on the back of the first glass substrate to carbonize the interface between the first glass substrate and the first flexible substrate layer 1, thereby realizing separation of the first glass substrate and the first flexible substrate layer 1. The first flexible substrate layer 1 is prepared by the coating process and laser lift-off, which can realize the preparation of an ultra-thin first flexible substrate layer 1, further reduce the thickness of the pressure sensor, and improve the bending performance and pressure sensitivity of the pressure sensor.

[0090] In some optional embodiments, the step of providing the pressure-sensitive layer 5 and the bonding portion 7 disposed on one side of the pressure-sensitive layer 5 includes: providing a second glass substrate, and sequentially forming a second flexible substrate layer 6, a pressure-sensitive layer 5, and a bonding portion 7 on one side of the second glass substrate, such as Figures 11 to 13 As shown; the second glass substrate and the second flexible substrate layer 6 are separated by a laser lift-off process; the pressure-sensitive layer 5 is placed on the side of the electrode layer 4 away from the first flexible substrate layer 1, so that the pressure-sensitive layer 5 and the insulating portion 8 are connected through the adhesive portion 7.

[0091] In this embodiment, the laser lift-off process can also be used to separate the second glass substrate and the second flexible substrate layer 6 to achieve separation of the second glass substrate and the second flexible substrate layer 6. The first flexible substrate layer 1 is prepared by coating process and laser lift-off, which can achieve the preparation of ultra-thin second flexible substrate layer 6 and pressure-sensitive layer 5, further reduce the thickness of the pressure sensor, and improve the bending performance and pressure sensitivity of the pressure sensor.

[0092] In some optional embodiments, the step of forming the first insulating layer 3 on the side of the wiring layer 2 away from the first flexible substrate layer 1 includes forming a first insulating material layer (not shown in the figure) on the side of the wiring layer 2 away from the first flexible substrate layer 1 by chemical vapor deposition or coating process; patterning the first insulating material layer by photolithography process to form the first insulating layer 3 including vias, such as Figure 6 shown.

[0093] The first insulating layer 3 is prepared by using film forming processes such as CVD and / or coating and yellow light photolithography, which can realize the preparation of an ultra-thin insulating layer, reduce the thickness of the pressure sensor, and improve the resolution, sensing accuracy and sensitivity of the pressure sensor.

[0094] Similarly, the second insulating layer 9 disposed between the first flexible substrate layer 1 and the wiring layer 2 and the insulating portion 8 disposed between the bonding portion 7 and the first insulating layer 3 can be prepared using the same preparation process as the first insulating layer 3 to further reduce the thickness of the pressure sensor.

[0095] Optionally, the photolithography process includes the following steps: coating photoresist on one side of the first insulating material layer; exposing part of the photoresist using a patterned mask; removing the exposed part of the photoresist to form a patterned photoresist; etching the first insulating material layer not covered by the photoresist to form a via; and stripping the photoresist.

[0096] In some optional embodiments, the step of forming the wiring layer 2 on one side of the first flexible substrate layer 1 includes: forming a first metal material layer 2' on one side of the first flexible substrate layer 1 by physical vapor deposition, such as Fig.14 As shown; the first metal material layer 2' is patterned by a photolithography process to form a wiring layer 2, such as Figure 5 As shown; and / or, the step of forming the electrode layer 4 on the side of the first insulating layer 3 away from the first flexible substrate layer 1 includes: forming a whole layer of second metal material layer (not shown in the figure) on the side of the first insulating layer 3 away from the first flexible substrate layer 1 by physical vapor deposition; patterning the second metal material layer by a photolithography process to form the electrode layer 4.

[0097] In this embodiment, a physical vapor deposition process can be used in conjunction with a photolithography process to form an ultra-thin, highly conductive and high-density patterned wiring layer 2 and electrode layer 4, thereby reducing the thickness of the pressure sensor and improving the resolution, sensing accuracy and sensitivity of the pressure sensor.

[0098] The above-mentioned PVD / CVD / coating and other film-forming processes, yellow light photolithography processes, and laser lift-off processes are all mature preparation processes in the display field. They can realize large-area preparation of pressure sensors, have extremely high mass production feasibility, and can improve the stability and reliability of pressure sensors.

[0099] The above are only specific implementation methods of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

[0100] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

Claims

1. A pressure sensor, characterized in that: include: a first flexible substrate layer; A wiring layer, provided on one side of the first flexible substrate layer; A first insulating layer, provided on a side of the routing layer away from the first flexible substrate layer, the first insulating layer comprising a via; An electrode layer, disposed on a side of the first insulating layer away from the first flexible substrate layer, the electrode layer comprising a pressure sensing electrode, and the pressure sensing electrode is electrically connected to the routing layer through the via hole; a pressure-sensitive layer, arranged on a side of the electrode layer away from the first flexible substrate layer, the orthographic projection of the pressure-sensitive layer on the first flexible substrate layer and the orthographic projection of the pressure-sensing electrode on the first flexible substrate layer at least partially overlap, the pressure-sensitive layer and the first insulating layer are connected via an adhesive portion, and the pressure-sensitive layer, the electrode layer, and the adhesive portion form a cavity structure; The second flexible substrate layer is arranged on a side of the pressure-sensitive layer away from the first flexible substrate layer.

2. The pressure sensor according to claim 1, characterized in that: It also includes an insulating portion, which is disposed between the bonding portion and the first insulating layer; Preferably, the thickness of the insulating portion is greater than or equal to the thickness of the electrode layer; Preferably, the thickness of the insulating portion is greater than or equal to 0.2 μm and less than or equal to 1.2 μm; Preferably, the thickness of the electrode layer is greater than or equal to 0.2 μm and less than or equal to 1.2 μm; Preferably, the thickness of the routing layer is greater than or equal to 0.2 μm and less than or equal to 1.2 μm; Preferably, the thickness of the first insulating layer is greater than or equal to 0.2 μm and less than or equal to 0.6 μm.

3. The pressure sensor according to claim 1, characterized in that: It also includes a second insulating layer, which is arranged between the first flexible substrate layer and the wiring layer, and the thickness of the second insulating layer is greater than or equal to 0.1 μm and less than or equal to 2 μm; Preferably, the first insulating layer and the second insulating layer are made of the same material; Preferably, the first insulating layer and the second insulating layer both comprise inorganic materials; Preferably, the first insulating layer and the second insulating layer both include at least one of silicon oxide, silicon nitride and silicon oxynitride.

4. The pressure sensor according to claim 1, characterized in that: The second flexible substrate layer and the first flexible substrate layer are made of the same material; Preferably, the first flexible substrate layer and the second flexible substrate layer comprise insulating material; Preferably, the first flexible substrate layer and the second flexible substrate layer both include polyimide and polyethylene terephthalate; Preferably, the thickness of the first flexible substrate layer and the second flexible substrate layer are both greater than or equal to 5 μm and less than or equal to 20 μm.

5. The pressure sensor according to claim 1, characterized in that: The electrode layer includes a first electrode structure and a second electrode structure insulated from each other, the first electrode structure includes a plurality of first electrode blocks arranged and electrically connected along a first direction, the plurality of first electrode structures are arranged at intervals along a second direction, the second electrode structure includes a plurality of second electrode blocks arranged and electrically connected along the second direction, the plurality of second electrode structures are arranged at intervals along the first direction, and the first direction and the second direction intersect.

6. A method for preparing a pressure sensor, characterized in that: The following steps are involved: providing a first flexible substrate layer; forming a wiring layer on one side of the first flexible substrate layer; Forming a first insulating layer on a side of the routing layer away from the first flexible substrate layer, wherein the first insulating layer includes a via hole; An electrode layer is formed on a side of the first insulating layer away from the first flexible substrate layer, wherein the electrode layer includes a pressure sensing electrode, and the pressure sensing electrode is electrically connected to the wiring layer through the via hole; Providing a second flexible substrate layer, and sequentially forming a pressure-sensitive layer and an adhesive portion provided on one side of the pressure-sensitive layer on one side of the second flexible substrate layer; The pressure-sensitive layer is placed on the side of the electrode layer away from the first flexible substrate layer, so that the pressure-sensitive layer and the first insulating layer are connected through the bonding portion, the orthographic projection of the pressure-sensitive layer on the first flexible substrate layer and the orthographic projection of the pressure-sensing electrode on the first flexible substrate layer at least partially overlap, and the pressure-sensitive layer, the electrode layer and the bonding portion form a cavity structure.

7. The method for preparing a pressure sensor according to claim 6, characterized in that: The step of providing the first flexible substrate layer includes: providing a first glass substrate; forming the first flexible substrate layer on one side of the first glass substrate by a coating process; Between the steps of forming an electrode layer on the side of the first insulating layer away from the first flexible substrate layer and providing a pressure-sensitive layer and an adhesive portion disposed on one side of the pressure-sensitive layer, the method further includes: forming an insulating portion on a side of the first insulating layer facing away from the first flexible substrate layer; The first glass substrate and the first flexible substrate layer are separated by a laser lift-off process.

8. The method for preparing a pressure sensor according to claim 7, characterized in that: The step of providing a pressure-sensitive layer and an adhesive portion disposed on one side of the pressure-sensitive layer includes: Providing a second glass substrate, and sequentially forming the second flexible substrate layer, the pressure-sensitive layer, and the bonding portion on one side of the second glass substrate; Separating the second glass substrate from the second flexible substrate layer by a laser lift-off process; The pressure-sensitive layer is placed on a side of the electrode layer away from the first flexible substrate layer, so that the pressure-sensitive layer and the insulating portion are connected via the adhesive portion.

9. The method for preparing a pressure sensor according to claim 6, characterized in that: The step of forming a first insulating layer on a side of the wiring layer away from the first flexible substrate layer includes: forming a first insulating material layer on a side of the wiring layer away from the first flexible substrate layer by chemical vapor deposition or coating process; Patterning the first insulating material layer by a photolithography process to form the first insulating layer including a via hole; Preferably, the photolithography process comprises the following steps: Applying photoresist on one side of the first insulating material layer; exposing a portion of the photoresist using a patterned mask; removing the exposed portion of the photoresist to form a patterned photoresist; Etching the first insulating material layer not covered by the photoresist to form the via hole; The photoresist is stripped.

10. The method for preparing a pressure sensor according to claim 6, characterized in that: The step of forming a wiring layer on one side of the first flexible substrate layer includes: forming a first metal material layer on one side of the first flexible substrate layer by physical vapor deposition; patterning the first metal material layer by photolithography to form the wiring layer; And / or, the step of forming an electrode layer on the side of the first insulating layer away from the first flexible substrate layer includes: forming a whole second metal material layer on the side of the first insulating layer away from the first flexible substrate layer by physical vapor deposition; and patterning the second metal material layer by a photolithography process to form the electrode layer.

Images