CN112798163B

CN112798163B - Preparation method of nanowire pressure sensor

Info

Publication number: CN112798163B
Application number: CN201911109178.9A
Authority: CN
Inventors: 解婧; 李超波; 邢建鹏; 林琳; 刘金虎; 刘瑞琪; 郜晨希
Original assignee: Institute of Microelectronics of CAS
Current assignee: Institute of Microelectronics of CAS
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2022-10-21
Anticipated expiration: 2039-11-13
Also published as: CN112798163A

Abstract

The embodiment of the invention provides a preparation method of a nanowire pressure sensor, which comprises the following steps: obtaining an organic material substrate; preparing a groove array on the substrate according to a nanowire array structure required to be obtained; filling a conductive material in the groove array to form a nanowire array; wherein the nanowire array comprises a plurality of nanowire units; attaching a metal electrode connected with the nanowire array on the substrate to obtain a nanowire pressure sensor; wherein each nanowire unit is connected with at least one metal electrode. The method provided by the invention can be used for preparing the pressure sensor with high perceptibility and is suitable for preparing the pressure sensor in a large range.

Description

Preparation method of nanowire pressure sensor

Technical Field

The invention relates to the technical field of microelectronics and semiconductors, in particular to a preparation method of a nanowire pressure sensor.

Background

At present, the basic principle of strain-type pressure sensors is to effectively convert the deformation of a foreign object into a detectable electric signal, and the sensing modes of the strain-type pressure sensors include piezoresistive, piezoelectric, capacitive, photoelectric effect and other electromechanical sensing mechanisms. Among them, the piezoresistive pressure sensor is the most widely type in research and application fields, and the pressure change can be conveniently sensed by an electrical real-time detection system through detecting the resistance change of a material by a mechanical variable. In addition, the pressure sensitive unit of the capacitive pressure sensor is usually a capacitance structure with variable parameters, and the capacitance value is changed by changing parameters such as the capacitance distance d, the capacitance area s, the dielectric constant epsilon and the like, so as to reflect different pressure states.

However, the existing pressure sensor preparation method can only prepare a pressure sensor with a small area, and the prepared sensor has low sensing precision and is difficult to be mutually matched for use in a large area range.

Disclosure of Invention

In view of the above, an object of the embodiments of the present invention is to provide a method for manufacturing a nanowire pressure sensor, which can manufacture a pressure sensor with high sensitivity and is suitable for manufacturing a pressure sensor with a large area.

In a first aspect, the present application provides the following technical solutions through an embodiment:

a method of making a nanowire pressure sensor, the method comprising:

obtaining an organic material substrate;

preparing a groove array on the substrate according to a nanowire array structure required to be obtained;

filling a conductive material in the groove array to form a nanowire array; wherein the nanowire array comprises a plurality of nanowire units;

attaching a metal electrode connected with the nanowire array on the substrate to obtain a nanowire pressure sensor; wherein each nanowire unit is connected with at least one metal electrode.

Preferably, before the filling of the conductive material in the groove array to form the nanowire array, the method further includes:

carrying out surface treatment on the surface with the groove array on the substrate; the surface treatment is one or more of plasma treatment, oxidant soaking, high-temperature treatment and laser irradiation.

covering a mask in a non-groove area on the substrate;

wherein, after the groove array is filled with the conductive material to form the nanowire array, the method comprises the following steps:

the mask is removed.

Preferably, after the attaching the metal electrode connected to the nanowire array on the substrate, the method includes:

and carrying out high-temperature setting treatment on the substrate.

Preferably, the substrate is a flexible film substrate, and the metal electrode connected to the nanowire array is attached to the substrate to obtain the nanowire pressure sensor, including:

attaching a metal electrode connected with the nanowire array on the substrate;

attaching the flexible film substrate to a surface layer of a target structure; wherein, the target structure is a structure needing pressure detection;

and carrying out high-temperature treatment on the nanowire array, the metal electrode and the substrate to obtain the nanowire pressure sensor.

Preferably, before the attaching the metal electrode connected to the nanowire array on the substrate, the method further comprises:

attaching a metal adhesion layer at the position where the metal electrode is attached;

and attaching a metal electrode connected with the nanowire array on the metal adhesion layer.

Preferably, the planar structure formed by the groove array is honeycomb-shaped.

Preferably, the metal electrode has a width ranging from 1 μm to 1mm and a thickness ranging from 100nm to 1 μm.

Preferably, the width of the groove is 500nm-100 μm.

Preferably, the groove array comprises a first groove array and a second groove array, each of the first groove array and the second groove array comprises a plurality of groove units, and a groove unit of the second groove array is arranged between every two adjacent groove units of the first groove array. .

According to the preparation method of the nanowire pressure sensor, an organic material substrate is obtained; the organic material substrate can facilitate high-temperature processing and shaping. Then, preparing a groove array on the substrate according to the nanowire array structure required to be obtained; conductive materials are filled in the groove array to form a nanowire array, and the filled nanowire array can be more uniform and reliable through the guiding of the grooves; the nanowire array comprises a plurality of nanowire units; attaching a metal electrode connected with the nanowire array on the substrate to obtain a nanowire pressure sensor; because the plasticity is ensured by selecting the organic material substrate, and meanwhile, the conductive material attached to the substrate forms the nanowire array through the limitation of the groove, the nanowire array has high uniformity and high sensitivity, and can sense the fine deformation of any area on the substrate, and the finally prepared pressure sensor has a high-sensing degree; meanwhile, the method is also suitable for preparing large-area pressure sensors in an array mode.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic cross-sectional structure diagram of a first implementation of a nanowire pressure sensor according to a first embodiment of the present invention;

FIG. 2 is a schematic plan view of a first implementation of a nanowire pressure sensor according to a first embodiment of the present invention;

FIG. 3 is a schematic cross-sectional structure diagram of a second implementation of a nanowire pressure sensor provided in the first embodiment of the present invention;

FIG. 4 is a schematic diagram of a planar structure of a second implementation of the nanowire pressure sensor provided in the first embodiment of the invention;

fig. 5 is a schematic plan view illustrating a nanowire unit of a nanowire pressure sensor according to a first embodiment of the present invention;

FIG. 6 is a schematic plan view of a first implementation of a sensor array according to a first embodiment of the present invention;

FIG. 7 is a schematic plan view of a second implementation of a sensor array according to the first embodiment of the invention;

FIG. 8 is a schematic plan view of a first implementation of a nanowire array provided in accordance with a first embodiment of the present invention;

FIG. 9 is a schematic plan view of a second implementation of the nanowire array provided in the first embodiment of the invention;

FIG. 10 is a process flow diagram of the implementation steps of a method of fabricating a nanowire pressure sensor according to a second embodiment of the present invention;

FIG. 11 is a process flow diagram of a first implementation of a method for fabricating a nanowire pressure sensor according to a second embodiment of the invention;

FIG. 12 is a process flow diagram of a second implementation of a method for fabricating a nanowire pressure sensor according to a second embodiment of the invention;

fig. 13 is a process flow diagram of a third implementation of a method for fabricating a nanowire pressure sensor according to the second embodiment of the invention;

fig. 14 is a process flow diagram of a fourth implementation of a method for fabricating a nanowire pressure sensor according to the second embodiment of the invention.

Icon: 100-nanowire pressure sensors; 200-a sensor array; 10-a substrate; 20-nanowire arrays; 21-a groove; 22-nanowire unit; 30-a metal electrode; 31-a backbone structure; 32-branched structure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "upper", "lower", and the like refer to orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships conventionally placed when the products of the present invention are used, and are used only for convenience of description and simplification of the description, but do not indicate or imply that the devices or elements referred to must have specific orientations, be constructed and operated in specific orientations, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

First embodiment

Referring to fig. 1 and 2, the present embodiment provides a nanowire pressure sensor 100, which includes: a substrate 10, a nanowire array disposed on the substrate 10, and a metal electrode 30 disposed at an edge of the substrate 10.

Specifically, the above-described configuration includes the following embodiments in the present embodiment:

a substrate 10 for supporting the nanowire array.

In this embodiment, most of the structural components that need to be subjected to pressure detection or monitoring are uneven, for example, have a certain radian, corner, angle of inflection, and the like; therefore, the material of the substrate 10 can be a flexible material, which is used as a compliant material for the pressure location to be measured, so as to comprehensively test the surface stress condition of the structural member. Specifically, the flexible material includes, but is not limited to, dimethyl siloxane (PDMS), polyimide (PI), polyethylene terephthalate (PET), and Polyurethane (PU), polyethylene (PE), polyethylene naphthalate (PEN), cellulose compound (Cellulose), and the like. Transparent substrates can be used in cabin or window structures of large-area transparent stealth equipment, for example, a substrate 10 with good light transmittance can be used in windshields (e.g., airplanes, automobiles, ships, naval vessels, etc.) with requirements on light transmittance, preferably dimethyl siloxane (PDMS), polyimide (PI), polyethylene terephthalate (PET), and Polyurethane (PU), polyethylene (PE), and polyethylene naphthalene (PEN).

Further, in order to ensure good light transmittance and deformation degree, the thickness of the substrate 10 may be set to 5um to 1mm.

In addition, the material of the substrate 10 can also be hard material, i.e. the substrate 10 directly measuring the pressure. Specifically, the engineering plastic may be rigid engineering plastic, including but not limited to Polycarbonate (PC), polystyrene Plastic (PS), polymethyl methacrylate (PMMA), polyurethane (PU), cyclic Olefin Polymer (COP), cyclic Olefin Copolymer (COC), and the like.

The substrate 10 may be a large-area substrate, and multiple sets of metal electrodes 30 and arrays of nanowire arrays may be performed on the substrate 10 (i.e., the nanowire sensor array 200 is formed directly on the entire substrate, see the description of the sensor array 200 below).

The substrate 10 may be provided with a groove 21 for arranging the nanowire array, which is also beneficial to improving the stability of the nanowire array and improving the preparation efficiency. The grooves 21 on the substrate 10 are also arranged in an array corresponding to the nanowire array 20. The width of the nanowires in this and subsequent embodiments is not meant to be limiting, but rather is to be understood broadly, as the width is determined by the width of the grooves 21. The orientation and distribution of the grooves 21 may determine the shape of the nanowire array.

It is noted that in some embodiments, the nanowire array 20 may be directly attached to the surface of the substrate 10 without the groove 21.

Specifically, the width of the groove 21 can be controlled within a range of 500nm to 100 μm, and the depth of the groove 21 can be controlled within a range of 50nm to 10 μm. The cross-sectional shape of the groove 21 is not limited, and may be: the structure comprises a rectangular structure, an inclined side wall trapezoidal structure, a semicircular structure or a cambered side wall of a steep side wall, wherein the inclined direction of the inclined side wall can be that the openings are close to each other or that the openings are far away from each other; two cambered surfaces of the cambered surface side wall can be close to each other to form an arc shape, and can also be far away from each other to form an arc shape.

And a metal electrode 30 for applying a voltage or current to the nanowire array 20.

Specifically, the metal electrodes 30 may be disposed on two sides of the grooves 21 of the nanowire array 20, or may be disposed on two sides of one or more grooves 21, and the metal electrodes 30 and the grooves 21 are located on the same side of the substrate 10, as shown in fig. 1 or 3. The metal electrodes 30 may form a wire array, as shown in fig. 3. The metal electrode 30 can be a low resistivity material such as gold Au, copper Cu, aluminum Al, silver Ag, platinum Pt, molybdenum Mo, tungsten W, magnesium Mg, etc., and different metal electrodes 30 can be selected for use as required, which is convenient for adjustment. In order to obtain better bottom adhesion, adhesion and finished product structure reliability, adhesion layer materials including chromium Cr, nickel Ni, titanium Ti and the like can be added between the metal material and the substrate. The line width of the metal electrode 30 is 1 μm to 1mm, the thickness is 100nm to 1 μm, and the line width, thickness and structure of the metal electrode 30 can be adjusted according to the requirements of light transmittance, electromagnetic shielding and the like. Further, the metal electrode 30 may be directly disposed on the surface of the substrate 10, or a corresponding mounting groove may be formed on the substrate 10 for disposing the metal electrode 30.

Referring to fig. 4, in a further embodiment, the metal electrodes 30 in one direction (e.g., in a transverse arrangement or a longitudinal arrangement) can be introduced into another direction. Specifically, the metal electrodes 30 (including the first electrode and the second electrode) on each sensor in the sensor array 200 are diagonally disposed, and specifically, if the upper surface of the substrate 10 is square (e.g., rectangular, square), the first electrode may be disposed on two adjacent edges of the upper surface of the square substrate, and the second electrode is disposed on the other two adjacent edges of the upper surface of the square substrate, and the first electrode and the second electrode form a diagonal structure, as shown in fig. 4. Therefore, the uniformity of the nanowire pressure sensor 100 can be further improved, and the testing accuracy is ensured; and such a design structure can significantly improve the uniformity and electromagnetic shielding performance of the sensor array 200 after the nanowire pressure sensors 100 are arrayed.

When the sensor array 200 covers a large area of the equipment surface, each nanowire pressure sensor 100 correspondingly detects the pressure change at one position, so as to finely sense the stress condition of each area of the equipment surface.

And a nanowire array 20 disposed in the groove 21 for sensing a pressure state change. The nanowire array 20 comprises more than two nanowire units 22, and each nanowire unit 22 is connected to at least one metal electrode 30. Two specific implementations are provided in this example:

1. capacitive type

A capacitance structure is formed by the nanowire array 20, the nanowire array 20 of the capacitance structure forms a pressure sensitive unit, the capacitance value is changed by changing parameters such as the capacitance distance d, the capacitance area s and the dielectric constant epsilon, and the capacitance value is influenced by the change of the parameters when external pressure is applied, so that pressure measurement is indirectly realized. In the process of directly applying the electrical parameter change to test the pressure by the capacitive nanowire array 20, the pressure stress sensitivity is very high, and the high sensitivity can enable the sensor to obtain lower energy consumption and wider application potential.

Specifically, the nanowire array 20 may include a first nano-array connected to the first metal electrode and a second nano-array connected to the second metal electrode, such that the first nano-array and the second nano-array may include a plurality of branch structures 32 thereon, and the branch structures 32 between the first nano-array and the second nano-array are not in contact with each other, forming a space, preferably a uniform space. The first nano array and the second nano array form a capacitor structure. Further, the nanowire units 22 of the first nano-array and the nanowire units 22 of the second nano-array have one or more trunk structures 31, the trunk structures 31 and the metal electrodes 30 are vertically distributed, the branch structures 32 are connected to the trunk structures 31, and the branch structures 32 are arranged in an array when connected to the trunk structures 31, as shown in fig. 5. The branch structures 32 of the first nano-array and the branch structures 32 of the second nano-array are arranged in a staggered manner. That is, the trunk structures 31 of the first nano array and the trunk structures 31 of the second nano array are arranged at intervals, wherein a trunk structure 31 of the second nano array exists between every two adjacent trunk structures 31 of the first nano array; the branch structures 32 of the first nano array and the branch structures 32 of the second nano array are arranged at intervals, wherein a branch structure 32 of the second nano array exists between every two adjacent branch structures 32 of the first nano array. The finally formed nanowire array 20 has a uniform branch structure 32, can sense a weak pressure change in a certain area, and has the characteristic of accurately positioning a pressure point with high precision.

It should be noted that, in the present embodiment, the nanowire array 20 may also include only the trunk structure 31.

Referring to fig. 6 and 7, the single sensor structure formed by the substrate 10, the metal electrode 30, the nanowire array 20, and the like can be used as an integral unit to form an array, and the sensor array 200 with a large area can be formed as required, so that the arrangement direction of each integral unit can be consistent when the array is performed, as shown in fig. 6. Preferably, the arrangement directions of the nanowire arrays 20 in each two adjacent integral units are perpendicular to each other at 90 degrees (which can be understood as being approximately 90 degrees to allow error generation, and the higher the precision, the better the effect), in this case, the nanowire sensor shown in fig. 4 may be preferably arrayed, and the array is shown in fig. 7. Such a distribution structure can ensure that the sensor array has higher consistency, and can also avoid that cumulative errors are generated after a plurality of integral units form the array, so that the test result is not accurate enough, that is, the sensor array 200 includes a first sensing array and a second sensing array, and the main structure 31 of the nanowire of the first sensing array is perpendicular to the main structure 31 of the nanowire of the second sensing array.

2. Resistance type resistor

The resistance sensor formed by the nanowire array 20 senses pressure change conveniently by an electrical real-time detection system by detecting the resistance change of a material according to mechanical variables. Specifically, the nanowire array 20 formed on the substrate 10 is a conductive unit array structure, specifically, a mesh structure is formed after the array, the metal electrode 30 is connected to the edge of the nanowire array 20, and the connection positions may be two opposite side edges of the nanowire array 20. The mesh shape of the network structure of the nanowire array 20 formed therein may have various embodiments, and the mesh shape may be as follows: square (square or rectangular, as shown in fig. 8), regular hexagon (as shown in fig. 9), and triangle, etc., without limitation. In this embodiment, the preferred mesh shape may be a regular hexagon, the mesh shape of the regular hexagon may form a honeycomb-shaped (a honeycomb-shaped groove array needs to be formed when preparing) nanowire array 20, the honeycomb-shaped nanowire array has the characteristic of good light transmittance, and when being applied to a structural member having a light transmission requirement, light has better passing ability, and when being applied to a large-area transparent stealth equipment cabin or window structure, the light has a greater advantage.

In the embodiment, when the nanowire pressure sensor 100 and the sensor array 200 are used for detecting, a constant voltage (corresponding to a capacitance type) or a current (corresponding to a resistance type) may be applied to the metal electrode 30, and the magnitude of the pressure value borne by the structural region may be detected by detecting a change of the corresponding current or voltage.

In the nanowire pressure sensor 100 and the sensor array 200 of the present embodiment, the nanowire pressure sensor 100 is composed of a substrate made of a material and an electrical sensing material mainly composed of nanowires with excellent electrical and mechanical properties and fixedly distributed in the groove 21. The nanowire array 20 is used as a signal sensing and conducting structure, material strain is sensed through electrical signal changes such as resistivity or capacitance parameters, pressure data are obtained, and the nanowire pressure sensor 100 is strong in expansibility and can be applied and expanded in a large area; and the pressure sensor based on the nano wire can acquire pressure signals with large range, high sensitivity and high stability at low voltage and with low energy consumption and high response speed. The nano-scale nanowire line width ensures high transparency and flexibility, and when a flexible organic material is used as a substrate material carried by the nanowire array 20, the nanowire pressure sensor 100 and the sensor array 200 can be widely applied to flexible touch displays, electronic skins, soft robots, dynamic energy collectors and the like. Meanwhile, the pressure sensor has excellent light transmittance and an electromagnetic shielding function, and can be used in a large-area transparent stealthy equipment cabin or window structure.

Second embodiment

Referring to fig. 10 and 11, a method for fabricating a nanowire pressure sensor is provided in the present embodiment, and the fabrication method can be used to fabricate the nanowire pressure sensor and the sensor array in the first embodiment. The method comprises the following steps:

step S10: obtaining an organic material substrate;

step S20: preparing a groove array on the substrate according to a nanowire array structure required to be obtained;

step S30: filling a conductive material in the groove array to form a nanowire array; wherein the nanowire array comprises a plurality of nanowires;

step S40: attaching a metal electrode connected with the nanowire array on the substrate to obtain a nanowire pressure sensor; wherein each nanowire unit is connected with at least one metal electrode.

In step S10, the substrate may be a transparent substrate or an opaque substrate; suitable organic solid materials may be selected as the substrate for support. If the pressure sensor is used as a bonding material of a pressure position to be measured, the pressure sensor can be a flexible organic material, the types of the flexible organic material comprise dimethyl siloxane (PDMS), polyimide (PI), polyethylene terephthalate (PET), polyurethane (PU), polyethylene (PE), polyethylene naphthalene (PEN), cellulose compound (Cellulose) and the like, and the thickness of the flexible organic material ranges from 5 micrometers to 1mm. If the material is used as the substrate material for directly measuring the pressure, the material can be hard engineering plastics including PC, PS, PMMA, PU, COP, COC and the like.

Further, the shape of the substrate is not limited, and may be flat, hard, flexible, film-like, or hard arc-shaped.

In step S20, the process for forming the groove may be selected according to the structure and size range of the nanowire array, including but not limited to a semiconductor process, a laser processing process, a multi-axis numerical control process, and the like. After the determination process, the nanowire array structure of the array may be processed or etched as required, and the array shape may be, for example, a honeycomb shape, a square grid shape, or a strip shape distributed in a staggered manner, which is described in the first embodiment. For example, for a groove array pattern with the nanowire line width larger than 10 μm, the groove array structure can be prepared by adopting a multi-axis numerical control machine tool machining mode and the like; for the groove array pattern with the nanowire line width larger than 500nm, the preparation of the groove array structure can be realized by adopting the modes of photoetching, plasma dry etching and the like; for the groove array pattern with the nanowire line width larger than 5um, a laser processing technology of 5um can be adopted; for the groove array pattern with the nanowire line width larger than 1nm and smaller than 1um, electron beam etching can be adopted.

For example, in the case of a capacitive pressure sensor, the groove array should be prepared to include: the first groove array and the second groove array respectively comprise a plurality of groove units (single bodies in the arrays), and a groove unit of the second groove array is arranged between every two adjacent groove units of the first groove array, so that the capacitor structure can be formed after the conductive nanowires are filled in the grooves.

In step S30, the specific method for filling the conductive nanowires into the grooves may be to perform liquid region selection covering after surface treatment, perform region selection covering under the guidance of an electric field, blade-coat the liquid nanowires, coat a silica gel dip stick, and the like. For example, when the substrate is in a hard arc shape, selective coverage can be performed under the guidance of an electric field, or coating can be performed under the condition of applying the electric field, so that the grooves of the arc-shaped substrate are filled with the nanowire arrays.

Referring to fig. 12, before performing step S30, step S301 may be further included: the substrate is subjected to surface treatment, and both surfaces of the substrate can be specifically treated or only the surface with the groove array on the substrate can be treated. The surface treatment operation includes one or more of plasma treatment, oxidant soaking, high temperature and/or laser irradiation to improve the affinity of the substrate surface for the adhesion of the nanowires.

Further, before step S30, step S302 may be further included: and covering a mask on the non-groove area of the substrate. The mask can be used for gluing, photoetching and pattern preparation by a semiconductor processing method; the mask can also be directly formed by laser processing technology and multi-axis numerical control processing and other schemes to prepare the shadow mask which can be conveniently removed after the nanowire is coated. The area which is not covered with the conductive nanowire material can be subjected to insulation protection through the mask, and the nanowire array is only filled in the groove, so that the sensing pressure-sensitive capacitor structure and the sensing piezoresistance structure are not interfered and damaged in the later detection process.

In step S40, the prepared metal electrodes may be a pair of metal electrodes on the substrate, or a metal electrode array distributed between every two grooves, and the nanowire units in the nanowire array are connected to at least one metal electrode. Specifically, the metal electrode can be low-resistivity material such as Au, cu, al, ag, pt, mo, W, mg and the like. In order to obtain better bottom adhesion, adhesion and finished product structure reliability, adhesion layer materials including Cr, ni, ti and the like can be added between the metal material and the substrate.

The specific preparation process of the metal electrode can adopt the following processes:

metal stripping process, dry etching process, wet etching process and shadow mask metal patterning process. Taking a metal stripping process as an example, for example, the metal electrode is Al, a photoresist coating (spin coating, spray coating, suspension coating, etc.), an exposure (various exposure methods such as contact, step, maskless laser direct writing, etc.), a development, and other photolithography processes may be performed on the substrate, so that the photoresist is patterned according to design requirements; then, depositing an Al metal film (evaporation, sputtering, electroplating and the like) on the substrate covered with the patterned photoresist; then, the sample is subjected to a photoresist removal process (e.g., acetone soak and ultrasonic removal) to remove the photoresist and the metal attached to the surface thereof, the metal without the photoresist barrier portion is directly attached to the substrate, and finally the metal electrode is formed. Processes not explained in the present application can be carried out with reference to the prior art publications.

The addition of the adhesion layer material can be performed in the same manner as in the preparation of the metal electrode, specifically, the preparation of the adhesion layer is performed first and then the preparation of the metal electrode is performed in the same process in the preparation of the metal electrode, which can be specifically referred to the description of the specific preparation process of the metal electrode.

Further, referring to fig. 13, if the flexible film substrate is adopted in the present embodiment, step S40 or step S40 may further include step S50: the substrate is adhered to a surface layer of a target structure. The target structure is a structure which needs to be subjected to pressure detection, and specifically includes a planar structure, a curved surface structure or other irregular structures, for example, the target structure may be large-area cambered glass, a cambered surface or a curved surface display screen, and the like. If the target structure is transparent, the substrate, the nanowire array and the metal electrode can be subjected to high-temperature treatment after the adhesion is finished so as to improve the adhesion of the nanowire array and the metal electrode with the substrate and the adhesion of the substrate with the target structure, and the adhesion improvement effect on the nanowire array and the metal electrode with the substrate is more remarkable; for example, when the base material is PMMA and the target structure to be attached is a PET material, high temperature treatment at a temperature of 120 degrees or less may be performed. And an antireflection film can be coated to enhance the light transmission and electromagnetic shielding performance.

It should be noted that, after step S40, the sensor intermediate product obtained in step S30 may also be directly subjected to a high temperature treatment, and finally the nanowire pressure sensor is obtained, so that the adhesion between the nanowire array and the metal electrode and the substrate is improved, and the stability of the nanowire array is improved.

Further, referring to fig. 14, step S60 may be further included after step S40, in which the substrate is shaped at a high temperature to obtain a final required shape, so as to facilitate the preparation of a large-area pressure sensor.

In the method for manufacturing a nanowire pressure sensor provided in the embodiment, an organic material substrate is obtained; the organic material substrate can facilitate high-temperature processing and shaping. Then, preparing a groove array on the substrate according to the nanowire array structure required to be obtained; conductive materials are filled in the groove array to form a nanowire array, and the filled nanowire array can be more uniform and reliable through the guiding of the grooves; wherein the nanowire array comprises a plurality of nanowire units; attaching a metal electrode connected with the nanowire array on the substrate to obtain a nanowire pressure sensor; because the plasticity is ensured by selecting the organic material substrate, and meanwhile, the conductive material attached to the substrate forms the nanowire array through the limitation of the groove, the nanowire array has high uniformity and high sensitivity, and can sense the fine deformation of any area on the substrate, and the finally prepared pressure sensor has a high-sensing degree; meanwhile, the method can also be suitable for preparing large-area pressure sensors in an array mode.

In addition, according to the manufacturing method of the nanowire pressure sensor provided in this embodiment, the whole manufacturing process is matched with each other through multiple processes (including a semiconductor process, a laser processing process, multi-axis numerical control processing and the like), so that the precise graphical processing of the nanowire array network of the organic material substrate is completed, specific selection can be performed according to the structure and the size range of the nanowire array through specific processes, and finally, the whole manufacturing process can be completed by attaching the metal electrode to the substrate. In the preparation process, a flexible organic film material and a macro-deformable material can be used as a substrate material borne by the nanowire array, so that large-area expansibility pressure detection of the surface of the curved surface structure can be easily realized. The pressure detection of the nanowire pressure sensor prepared by the method is sensed by the deformation of the nanowire array, so that the detection with low energy consumption and high response speed can be realized, and the large-area substrate can be selected for etching the groove, so that the pressure signal acquisition with large range, high sensitivity and high stability can be carried out. Therefore, the pressure sensor can be widely applied to flexible touch-sensitive displays, electronic skins, soft robots, dynamic energy collectors and the like. Meanwhile, when the transparent substrate is selected for preparation, the nanowire pressure sensor has excellent light transmission performance and an electromagnetic shielding function, and can be used for preparation, optimization and other applications of a large-area plane or curved surface transparent stealth equipment cabin or window structure.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method of making a nanowire pressure sensor, the method comprising:

obtaining an organic material substrate;

preparing a plurality of groove arrays on the substrate according to the nanowire array structure required to be obtained; on the substrate, the arrangement directions between every two adjacent groove arrays are mutually vertical; each groove array comprises a first groove array and a second groove array, each of the first groove array and the second groove array comprises a plurality of groove units, and a groove unit of the second groove array is arranged between every two adjacent groove units of the first groove array;

filling a conductive material in the groove array to form a plurality of nanowire arrays; the arrangement directions of every two adjacent nanowire arrays are mutually vertical, and each nanowire array comprises a plurality of nanowire units;

2. The method of claim 1, wherein before filling the array of recesses with a conductive material to form the array of nanowires, further comprising:

carrying out surface treatment on the surface with the groove array on the substrate; the surface treatment is one or more of plasma treatment, oxidant soaking, high temperature treatment and laser irradiation.

3. The method of claim 1, wherein before filling the array of grooves with a conductive material to form the array of nanowires, further comprising:

covering a mask in a non-groove area on the substrate;

the mask is removed.

4. The method of claim 1, wherein after attaching the metal electrode connected to the nanowire array on the substrate, the method comprises:

and carrying out high-temperature setting treatment on the substrate.

5. The method of claim 1, wherein the substrate is a flexible film substrate, and the attaching of the metal electrodes connected to the nanowire array on the substrate to obtain the nanowire pressure sensor comprises:

attaching a metal electrode connected with the nanowire array on the substrate;

attaching the flexible film substrate to a surface layer of a target structure; the target structure is a structure needing pressure detection;

6. The method of claim 1, wherein prior to attaching the metal electrode connected to the nanowire array on the substrate, further comprising:

7. The method of claim 1 wherein the planar structure formed by the array of grooves is honeycomb-shaped.

8. The method of claim 1, wherein the metal electrode has a width in the range of 1 μm to 1mm and a thickness in the range of 100nm to 1 μm.

9. The method of claim 1, wherein the grooves have a width of 500nm to 100 μm.