Device pattern transfer method, flexible electronic device and application

Abstract

The invention belongs to the technical field of flexible sensors, and particularly relates to a device pattern transfer method, a flexible electronic device and application. According to the method, a three-layer composite flexible structure with low deformation quantity is designed, and the rigid substrate is stripped by adopting alkali liquor, so that the deformation of the device pattern can be reduced in the transfer process of the device pattern, the device pattern can be efficiently transferred from the rigid substrate to the flexible substrate, the aggregation and damage of the pattern are avoided, and the yield of the device pattern is improved. The preparation method has the advantages of being simple, efficient, safe, low in cost and the like, and is expected to be widely applied to transfer of device patterns. And the three-layer composite flexible structure is easy to store and easy to strip, so that a flexible electronic device with relatively thin thickness can be prepared.

Description

Technical Field

[0001] This application belongs to the technical field of flexible sensors, and particularly relates to a method for transferring device patterns, a flexible electronic device, and an application thereof. Background Art

[0002] Flexible electronics technology is an emerging field, and its main feature is that electronic devices are fabricated on flexible substrates, thereby achieving characteristics such as flexibility, thinness, and transparency. Flexible electronics technology has broad application prospects in the fields of wearable devices, intelligent healthcare, smart homes, etc. Electrodes and various devices are the basic components of flexible electronics, including common electrode materials, thin-film devices, etc. Common silicon process electrode pattern preparation methods, such as lithography and etching, can prepare high-precision metal patterns. Although these methods have achieved great success on rigid substrates (such as silicon substrates), their applications on flexible substrates are significantly limited by their heat resistance temperature, bendability, etc. This is mainly because these process methods will damage the physical and chemical stability of flexible substrates.

[0003] In recent years, with the rapid development of flexible materials and printing technologies, flexible electronic device fabrication technologies such as flexible stamp transfer have emerged. These technologies involve transferring electrodes or devices prepared by mature silicon processes to flexible substrates, thus attracting people's attention. However, these methods still face challenges in realizing the transfer and preparation of metal patterns, such as relying on a single flexible substrate material, limitations in the selection of printing materials, insufficient pattern resolution, and problems such as easy deformation, agglomeration, and pattern peeling and damage during the transfer process, and difficulties in storing and transporting flexible electrodes / devices after transfer.

[0004] Therefore, there is an urgent need to develop a method for transferring and preparing device patterns with complete device patterns, high resolution, easy storage and transportation, and high production efficiency. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this application is to overcome the defects in the prior art that the fabrication process of flexible electronic devices is immature, there are problems such as insufficient pattern resolution, easy deformation, agglomeration, peeling and damage during the transfer process, low production efficiency, and difficulty in storage and transportation, thereby providing a method for transferring device patterns, a flexible electronic device, and an application thereof.

[0006] To this end, this application provides the following technical solutions:

[0007] According to one aspect of this application, there is provided a method for transferring device patterns, including the following steps:

[0008] S1, prepare a rigid substrate, and fabricate a device pattern on the surface of the rigid substrate;

[0009] S2. Spin-coat a flexible substrate material layer on one side surface of the rigid substrate with the device pattern, leaving it in an uncured state;

[0010] S3. Prepare a polyethylene terephthalate film and fabricate a water-soluble organic binder layer on one side surface thereof, wherein the size of the water-soluble organic binder layer is smaller than that of the flexible substrate material layer;

[0011] S4. Cover the water-soluble organic binder layer onto the flexible substrate material in S2 and cure it;

[0012] S5. Assist in peeling the rigid substrate with alkali solution to obtain a composite structure film, realizing the transfer of the device pattern.

[0013] According to another aspect of the present application, there is provided a method for manufacturing a flexible electronic device, including the following steps:

[0014] S11. Obtain a composite structure film according to the above method for transferring the device pattern;

[0015] S12. Separate the polyethylene terephthalate film from the flexible substrate to obtain a flexible electronic device.

[0016] According to another aspect of the present application, there is provided a flexible electronic device manufactured by the above manufacturing method.

[0017] According to another aspect of the present application, there is provided an application of the above flexible electronic device in the fields of wearable devices, intelligent healthcare or smart home.

[0018] The technical solution of the present application has the following advantages:

[0019] The method for transferring a device pattern provided by this application includes the following steps: S1, prepare a rigid substrate and fabricate a device pattern on the surface of the rigid substrate; S2, spin-coat a flexible substrate material on one surface of the rigid substrate with the device pattern, making it in an uncured state; S3, prepare a polyethylene terephthalate film and fabricate a water-soluble organic binder layer on one surface thereof, the size of the binder layer being smaller than that of the flexible substrate material layer; S4, cover the water-soluble organic binder layer onto the flexible substrate material layer in S2 and cure it; S5, assist in peeling off the rigid substrate with an alkaline solution to obtain a composite structure film, thereby realizing the transfer of the device pattern. By designing a three-layer composite flexible structure with low deformation, and cooperating with the use of an alkaline solution to peel off the rigid substrate, this method can reduce the deformation generated by the device pattern during the transfer process of the device pattern, can efficiently transfer the device pattern from the rigid substrate to the flexible substrate, avoid the agglomeration and damage of the pattern, maintain the integrity of the pattern and high pattern resolution, and improve the transfer yield. At the same time, this transfer method has the advantages of simple operation, high efficiency, safety and low cost, and is expected to be widely used in the transfer of device patterns. In addition, the composite structure film obtained by using the transfer method of this application is easy to store and also easy to peel off, and can be used to fabricate flexible electronic devices with a relatively thin thickness.

[0020] Additional aspects and advantages of the embodiments of this application will be described and shown in part in the subsequent description, or will be explained through the implementation of the embodiments of this application. Brief Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is the process flow chart of the preparation of the flexible electronic device in Embodiment 1 of this application;

[0023] Figure 2 is the schematic structural diagram of the preparation process of the flexible electronic device in Embodiment 1 of this application;

[0024] Figure 3 is the physical diagram formed in step S5 of Embodiment 1 of this application;

[0025] Figure 4 is the physical diagram formed in step S4 of Embodiment 2 of this application;

[0026] Figure 5 is the physical diagram of the flexible electronic device separated in step S5 of Embodiment 2 of this application;

[0027] Figure 6 It is a schematic diagram of the lamination of a composite structure film with two different device patterns in Embodiment 3 of the present application.

[0028] Reference numerals:

[0029] 1. Rigid substrate; 2. Device pattern; 3. Polydimethylsiloxane film layer; 4. Polyvinyl alcohol film layer; 5. Polyethylene terephthalate film layer; 6. First composite structure film; 7. Second composite structure film; 8. Third composite structure film. Detailed implementation manners

[0030] The following embodiments are provided to better further understand the present application. They are not limited to the described optimal implementation manners, and do not limit the content and protection scope of the present application. Any product that is the same as or similar to the present application obtained by anyone under the inspiration of the present application or by combining the features of the present application with other prior art features falls within the protection scope of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof herein are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of the present application, technical terms such as "first", "second", "third", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0033] Referring to "embodiment" herein means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0035] In the description of the embodiments of the present application, the term "at least one" means one or more than two (including two).

[0036] For those embodiments where specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0037] As described in the background art, the transfer preparation process of flexible electronic devices in the prior art is not mature, with problems such as insufficient pattern resolution, easy deformation, agglomeration, peeling and damage, as well as low production efficiency and difficulty in storing and transporting the devices after transfer. To solve these problems, the present application provides the following technical solutions:

[0038] According to one aspect of the present application, there is provided a method for transferring a device pattern, including the following steps:

[0039] S1, prepare a rigid substrate and fabricate a device pattern on the surface of the rigid substrate;

[0040] In the present application, the rigid substrate serves as the carrier of the pre-transfer electrode or circuit pattern, and an appropriate size can be selected according to the pattern.

[0041] In some alternative embodiments, the rigid substrate includes but is not limited to at least one of a silicon oxide substrate, a sapphire substrate, a titanium oxide substrate, etc.

[0042] In some alternative embodiments, a device pattern can be formed on the surface of the above-mentioned clean rigid substrate through semiconductor process lithography technology, thin film process technology, template method, etc.

[0043] In some alternative embodiments, the electrode material used for fabricating the device pattern is a conductive material, such as metals like gold, cadmium, silver, copper, etc., or low-conductivity materials such as two-dimensional materials (Mxene), graphene, organic conductive polymers, etc. can be used.

[0044] S2, spin-coat a flexible substrate material layer on the surface of the rigid substrate with the device pattern, so that it is in an uncured state;

[0045] In some alternative embodiments, S2 specifically includes: mixing the organic polymer solution for preparing the flexible substrate and the curing agent in a certain proportion, stirring evenly, standing in a vacuum environment at a low temperature (for example, -5°C to 5°C), forming a transparent and uniform solution, dropping the above solution on the surface of the rigid substrate with the fabricated device pattern, and using a spin coater to spin-coat to form a flexible substrate material thin film with a certain thickness.

[0046] In some optional embodiments, the curing agent is conventional in the art and includes at least one of, but is not limited to, platinum catalysts, silane coupling agents such as methyltrichlorosilane, propylsilane, phenyltrichlorosilane, or curing agents such as dithiodiketones, polyols, or amine compounds.

[0047] In the present application, when the flexible substrate material is spin-coated on the surface of the device pattern, it should remain in a semi-fluid or uncured state.

[0048] S3. Prepare a polyethylene terephthalate film, and prepare a water-soluble organic binder layer on one side surface thereof. The size of the water-soluble organic binder layer is smaller than the size of the flexible substrate material layer.

[0049] In the present application, there are no special requirements for the size difference between the water-soluble organic binder layer and the flexible substrate material layer, as long as the flexible substrate material layer can wrap the edge of the water-soluble organic binder layer, so as to protect the water-soluble organic binder layer in the step of alkali-assisted peeling of the rigid substrate, and avoid the dissolution of the water-soluble organic binder layer in this step, resulting in the failure of device pattern transfer.

[0050] In some optional embodiments, the surface of the polyethylene terephthalate film (PET film) is pre-cleaned with liquid and plasma.

[0051] Specifically, preparing the water-soluble organic binder layer includes: dissolving the water-soluble organic binder powder in deionized water at 60°C to 90°C to prepare a binder solution with a mass concentration of 5% to 10%.

[0052] Take the above-mentioned cleaned polyethylene terephthalate (PET) film, drop an appropriate amount of the water-soluble organic binder solution, use the spin-coating method at a rotation speed of 2000 rpm / min to 4000 rpm / min, and heat on a flat heater for 15 min to 60 min to form a PET / binder composite flexible film.

[0053] S4. Cover the water-soluble organic binder layer onto the flexible substrate material layer in S2 and cure it.

[0054] In some optional embodiments, the curing is carried out in a vacuum drying oven. After the flexible substrate material layer is cured, a three-layer flexible composite structure film is formed above the rigid substrate and the device pattern.

[0055] S5. Alkali-assisted peeling of the rigid substrate to obtain a composite structure film, realizing the transfer of the device pattern.

[0056] In some optional embodiments, in S2, the flexible substrate material includes an organic polymer solution and a curing agent with a mass ratio of 8:1 to 11:1. Among them, the organic polymer in the organic polymer solution includes one of polydimethylsiloxane, polyimide, and polyurethane. As an example, the mass ratio of the organic polymer solution to the curing agent can be 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, or within the range composed of any of the above values. In the present application, by adjusting the organic polymer solution and the curing agent, the flexibility of the flexible substrate can be adjusted. The lower the mass ratio of the two, the better the flexibility, and the larger the ratio, the harder it is. Those skilled in the art can select according to actual application requirements.

[0057] In some optional embodiments, the organic polymer solution can be obtained through commercial channels.

[0058] And / or, the spin coating thickness of the flexible substrate material layer is 20 microns to 200 microns. As an example, the spin coating thickness of the flexible substrate material layer can be 20 microns, 40 microns, 50 microns, 60 microns, 80 microns, 100 microns, 120 microns, 140 microns, 150 microns, 160 microns, 180 microns, 200 microns, or within the range composed of any of the above values.

[0059] In some optional embodiments, in S3, the thickness of the polyethylene terephthalate film (PET film) is 100 microns to 300 microns. As an example, the thickness of the polyethylene terephthalate film can be 100 microns, 120 microns, 140 microns, 150 microns, 160 microns, 180 microns, 200 microns, 220 microns, 240 microns, 250 microns, 260 microns, 280 microns, 300 microns, or within the range composed of any of the above values. In the present application, by limiting the thickness of the polyethylene terephthalate film, the support characteristics of the PET film can be ensured, and at the same time, it has a certain flexibility, which is beneficial to the attachment and transfer of the flexible substrate.

[0060] In some optional embodiments, in S3, the steps of preparing the water-soluble organic binder layer include: preparing an aqueous solution of the water-soluble organic binder with a mass concentration of 5% to 10%, coating it on the surface of the polyethylene terephthalate film, and heating to obtain the water-soluble organic binder layer. As an example, the mass concentration of the water-soluble organic binder solution can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or within the range composed of any of the above values.

[0061] In some optional embodiments, the heating temperature is 40°C to 60°C, and the heating time is 15 min to 60 min; as an example, the heating temperature can be 40°C, 45°C, 50°C, 55°C, 60°C, or within the range composed of any of the above values; the heating time can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, or within the range composed of any of the above values.

[0062] In this application, the function of the water-soluble organic binder layer is to bond the flexible substrate and the PET film, thereby realizing the transfer of the device pattern. The thickness of the water-soluble organic binder layer is 10 μm to 100 μm; as an example, the thickness of the water-soluble organic binder layer can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or within the range composed of any of the above values.

[0063] And / or, the water-soluble organic binder includes at least one of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), starch and its derivatives, sodium alginate or polyethylene oxide (PEO).

[0064] In some optional embodiments, in S4, the curing temperature is 60°C to 120°C, and the curing time is 8 hours to 24 hours. As an example, the curing temperature can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, or within the range composed of any of the above values; the curing time can be 8 hours, 10 hours, 12 hours, 14 hours, 15 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, or within the range composed of any of the above values. By limiting the curing temperature and curing time, this application can better achieve the curing of the flexible substrate and avoid the material decomposition or curing agent inactivation that may occur on its surface at too high a temperature.

[0065] In some optional embodiments, in S5, the method of alkali solution-assisted peeling of the rigid substrate includes mechanical peeling or alkali solution-assisted peeling;

[0066] In this application, the three-layer flexible composite structure film can be separated from the rigid substrate by an alkali solution-assisted peeling method, and at the same time, the device pattern is transferred to the surface of the flexible substrate under the flexible composite structure film. Since the polyethylene terephthalate (PET) film is limited by flexibility and strength and has a limited bending radius of curvature, it is more stable and can better support the flexible substrate, making it easier to store the flexible composite structure film and avoiding curling and agglomeration of the flexible substrate and damage to the device pattern.

[0067] In some alternative embodiments, the alkali solution-assisted peeling includes: placing the composite structure of the rigid substrate and the composite structure film obtained in S4 in an alkali solution and heating it at 40°C to 80°C for 5 hours to 12 hours; wherein, the concentration of the alkali solution is below 2000 mmol / L. For example, the concentration of the alkali solution can be 500 mmol / L to 2000 mmol / L. As an example, the concentration of the alkali solution can be 500 mmol / L, 800 mmol / L, 1000 mmol / L, 1200 mmol / L, 1400 mmol / L, 1500 mmol / L, 1600 mmol / L, 1800 mmol / L, 2000 mmol / L, or within the range composed of any of the above values. In the step of alkali solution-assisted peeling of the rigid substrate, the heating temperature can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or within the range composed of any of the above values; the heating time can be 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or within the range composed of any of the above values.

[0068] In this application, the alkali solution can be a potassium hydroxide solution or other alkaline solutions prepared in the laboratory. During the alkali solution-assisted peeling process, after heating for several hours, when bubbles are seen on the surface, it can assist in the self-separation of the flexible composite structure and the rigid substrate, and complete the transfer of the device pattern from the rigid substrate to the surface of the flexible substrate. During the alkali solution-assisted peeling process, by combining hydroxide ions with the rigid substrate to generate silicate, it is used for assisted peeling, which is convenient for obtaining a composite flexible material structure with lower deformation, can more quickly and completely peel the rigid substrate, and at the same time keep the flexible substrate and the devices on its surface from deforming or being damaged.

[0069] According to another aspect of the present application, a method for preparing a flexible electronic device is provided, including the following steps:

[0070] S11, obtaining a composite structure film according to the above device pattern transfer method;

[0071] S12, separating the polyethylene terephthalate film from the flexible substrate to obtain a flexible electronic device.

[0072] In some optional embodiments, the step of separating the polyethylene terephthalate film from the flexible substrate includes: immersing the composite structure film in water or an aqueous ethanol solution and heating it at 70°C to 90°C for 8 to 12 hours. As an example, the heating temperature can be 70°C, 75°C, 80°C, 85°C, 90°C, or within the range composed of any of the above values; the heating time can be 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or within the range composed of any of the above values.

[0073] In some optional embodiments, when the flexible electronic device includes a packaging structure, before separating the polyethylene terephthalate film from the flexible substrate in S12, it further includes: a step of vacuum bonding two composite structure films with the device pattern sides adjacent to each other. In this way, the flexible substrates in the two composite structure films can be used to package the device. When the device patterns on the two composite structure films are different, bonding them can also realize the preparation of an electronic device with a complex device pattern. Using two composite structure films with different device patterns to bond and prepare a device with a complex pattern can avoid the decrease in yield due to overly complex patterns compared to directly preparing a complex pattern device. By composite preparation, not only the complexity of preparing a single device pattern is reduced, but also preliminary packaging can be achieved, which cannot be realized by direct preparation.

[0074] In this application, the method of separating the polyethylene terephthalate film from the flexible substrate not only reduces the surface damage to the flexible substrate during peeling, but also has a cleaning effect, resulting in less residue on the surface of the flexible substrate and achieving a better flexible attachment effect with other surfaces. The dissolution rate of the water-soluble organic binder can be set and changed according to the molecular weight of the binder and the experimental environment. Since the above method of separating the polyethylene terephthalate film from the flexible substrate is simple to operate, it can be stored and transported in the form of a composite structure film, and the polyethylene terephthalate film and the flexible substrate are separated when in use to obtain a flexible electronic device.

[0075] It should be noted that in the step of separating the polyethylene terephthalate film from the flexible substrate, the redundant flexible substrate at the edge needs to be lifted or cut off first to expose the water-soluble organic binder layer, so that the water-soluble binder layer dissolves and the separation of the two is realized.

[0076] According to another aspect of the present application, there is provided a flexible electronic device prepared by the above preparation method.

[0077] According to another aspect of the present application, there is provided an application of the above flexible electronic device in the fields of wearable devices, intelligent healthcare, or smart home. Specifically, it may be used in technologies such as flexible circuit boards, curved sensors, wearable electronic devices, etc.

[0078] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0079] Embodiment 1

[0080] This embodiment provides a preparation method for a flexible electronic device, and its process flow chart is as Figure 1 shown, and the schematic structural diagram of the flexible electronic device preparation process is as Figure 2 shown. The method includes the following steps:

[0081] Step S1: Use a silicon oxide substrate as the rigid carrier of the initial device pattern. Select a rigid substrate 1 with a size of about 5 cm × 5 cm according to the pattern, and its surface color is yellowish-brown.

[0082] Clean the above-mentioned rigid substrate 1, and then lithograph the pattern through lithography technology. Evaporate the electrode material to form a device pattern 2 on the surface of the silicon oxide substrate. The electrode material used in this embodiment is gold, with a thickness of 50 nm. The vacuum thin film evaporation process is used for evaporating the electrode material. Clean with isopropyl alcohol solution, ethanol solution, deionized water, etc. in sequence to remove surface reaction residues. Dry the surface liquid with nitrogen.

[0083] Step S2: Prepare a polydimethylsiloxane (PDMS) basic component solution and a curing agent (Dow Corning DC184, the same below). The basic component solution and the curing agent are mixed in a ratio of 10:1, and after stirring evenly, they are left to stand at a low temperature of 5 °C in a vacuum environment to form a transparent, uniform, and bubble-free mixed solution. Drop the obtained mixed solution on the surfaces of the above-mentioned rigid substrate 1 and the device pattern 2, and use a spin coater at 3000 rpm for the spin coating process to form a polydimethylsiloxane (PDMS) material layer with a thickness in the range of 20 μm to 200 μm. The thickness in this embodiment is 150 μm. This material layer should be kept in an uncured state and placed in a freezer for standby.

[0084] Step S3: Prepare a clean polyethylene terephthalate (PET, with a molecular weight of about 30,000, the same below) film with a thickness of about 150 microns and a smooth surface. First, clean it successively with acetone, ethanol, and deionized water in an ultrasonic environment, and after drying, place it in a plasma cleaner for 5 minutes. Dissolve polyvinyl alcohol (PVA, with a molecular weight of about 100,000, the same below) powder in deionized water at 80 °C to prepare a polyvinyl alcohol (PVA) solution with a mass concentration of 8%. Take the above PET film, use the spin coating method at a rotation speed of 2000 rpm / min, and heat it on a flat heater at 60 °C for 30 min to form a PET / PVA composite flexible film, where the size of the PVA layer is slightly smaller than that of the PDMS material layer, so that the uncured PDMS material can wrap the edge of the PVA layer.

[0085] Step S4: Cover the PET / PVA double-layer composite film on the uncured polydimethylsiloxane (PDMS) film layer, place it in a vacuum drying oven and heat it at 80 °C for 20 hours to cure and obtain the polydimethylsiloxane film layer 3, forming a three-layer flexible composite structure with a polyethylene terephthalate film layer 5, a polyvinyl alcohol film layer 4, and a polydimethylsiloxane film layer 3 from top to bottom.

[0086] Step S5: In a laboratory environment, after heating in a potassium hydroxide solution (concentration of 1500 mmol / L) at 80 °C for 5 hours, peel off the rigid substrate, transfer the device pattern from the rigid substrate (silicon oxide substrate) to the three-layer flexible composite structure (PET / PVA / PDMS) substrate. The three-layer flexible composite structure is separated from the rigid substrate to achieve the transfer of the device pattern from the rigid substrate to the flexible substrate. Wash the device with deionized water and store it for standby.

[0087] Step S6: When in use, first lift the excess flexible substrate at the edge of the three-layer flexible composite structure so that the edge of the water-soluble organic binder layer can contact water or an ethanol solution. In this embodiment, transfer the three-layer flexible composite structure to deionized water, use a flat heater to heat the solution to 80 °C and keep it warm for 8 hours, and the PVA film layer can be dissolved to separate the PET film layer, thereby obtaining an ultra-thin and highly flexible polydimethylsiloxane (PDMS) film flexible electronic device. The physical diagram formed in this embodiment is as shown in the appendix Figure 3 shown.

[0088] Example 2

[0089] This embodiment provides a preparation method of a flexible electronic device, and its process flow chart is as shown in Figure 1 shown, and the method includes the following steps:

[0090] Step S1: The silicon oxide substrate serves as the carrier for the initial device pattern. Select a silicon oxide substrate sized approximately 5 cm × 5 cm according to the circuit pattern, and its surface color is yellowish-brown.

[0091] Clean the above-mentioned silicon oxide substrate. Through photolithography technology, perform multiple overlapped lithographies to fabricate a device pattern of a cross array on the surface of the silicon oxide substrate. The electrode material used for the device pattern is gold, with a thickness of 50 nm. During the multiple overlapped lithography processes, at the overlapping areas of the cross array, use aluminum oxide thin film material as the insulating material, and the thickness of the aluminum oxide thin film is approximately 30 nm. The device pattern and the aluminum oxide thin film layer are both prepared by vacuum evaporation process. Clean with isopropyl alcohol solution, ethanol solution, deionized water, etc. successively to remove surface reaction residues. Dry the surface liquid with nitrogen.

[0092] Step S2: Prepare the basic component solution of polydimethylsiloxane (PDMS) and the curing agent (Dow Corning DC184, the same below). The basic component solution and the curing agent are mixed in a ratio of 9:1, stirred evenly, and then left to stand at a low temperature of 0 °C in a vacuum environment to form a transparent, uniform, and bubble-free solution. Drop the prepared polydimethylsiloxane (PDMS) solution onto the above-mentioned silicon oxide substrate and the surface of the device pattern, and use a spin coater at 3000 rpm to perform a spin coating process to form a polydimethylsiloxane (PDMS) thin film layer with a thickness of about 150 microns. This thin film layer needs to remain uncured and be placed in the freezer for standby.

[0093] Step S3: Prepare a clean polyethylene terephthalate (PET) film with a thickness of about 200 microns and a smooth surface. First, clean it with acetone, ethanol, and deionized water in an ultrasonic environment, and after drying, place it in a plasma cleaner for 5 minutes. Dissolve polyvinyl alcohol (PVA) powder in deionized water at 80 °C to prepare a polyvinyl alcohol (PVA) solution with a mass concentration of 8%. Take the above-mentioned PET film, use the spin coating method at a speed of 2000 rpm / min, and heat it on a flat heater at 60 °C for 30 min to form a PET / PVA composite flexible film.

[0094] Step S4: Cover the PET / PVA double-layer composite film on the uncured polydimethylsiloxane (PDMS) thin film, and place it in a vacuum drying oven and heat it at 80 °C for 24 hours to cure the polydimethylsiloxane (PDMS) thin film layer, forming a three-layer flexible composite structure on the silicon oxide substrate and the device pattern, which from top to bottom are polyethylene terephthalate (PET) thin film layer, polyvinyl alcohol (PVA) thin film layer, and polydimethylsiloxane (PDMS) thin film layer. The physical diagram formed in this step is as shown in the appendix Figure 4 as follows.

[0095] Step S5, in a laboratory environment, after heating at 70°C for 5 hours in an auxiliary potassium hydroxide solution (concentration of 1200mmol / L), the rigid substrate is peeled off, the device pattern is transferred from the rigid substrate (silicon substrate) to the three-layer flexible composite structure (PET / PVA / PDMS) substrate, and the flexible device is transferred to deionized water, and the solution is heated to 80 degrees using a flat heater. After heating for 8 hours in the solution environment, the three-layer flexible composite structure is separated, and finally a flexible polydimethylsiloxane (PDMS) film with a device pattern is obtained in the solution, and the transfer of the device pattern is completed. The actual picture of the obtained flexible electronic device is as follows: Figure 5 shown.

[0096] Example 3

[0097] This embodiment provides a method for preparing a flexible electronic device with a packaging structure, and the specific steps and operating parameters are as follows:

[0098] In this embodiment, two devices with different device patterns (such as Figure 6 The preparation of the composite structure film (i.e., the PET / PVA / PDMS composite structure including the device pattern) of the first composite structure film 6 and the second composite structure film 7 on the left side, and further vacuum bonding the device pattern side of the first composite structure film 6 and the second composite structure film 7. Figure 6 As shown, the two figures on the left show two composite structure films that have completed the transfer, both of which use a flexible composite structure substrate, whose specifications and sizes are consistent, and a first composite structure film 6 and a second composite structure film 7 with two different device patterns designed. An insulating layer is set at the square block in the pattern array of the first composite structure film 6 (used for insulation at the intersection of device patterns in two different directions in the cross array to prevent short circuit), and the material is the same as the material used in the overlapping part of the above embodiment 2. The square block in the pattern array of the second composite structure film 7 represents a two-terminal device, which can be selected as a resistor device, a pressure-sensitive material, a photosensitive material, a memristor device, etc. Two-terminal devices. After aligning the above two flexible devices according to the cross array design and laminating the device patterns in a low vacuum environment, a third composite structure film 8 is formed. At this time, the composite flexible structure substrate can still maintain the shape of the device, and optionally, the device can be stored and transported in the form of the third composite structure film. When using flexible devices based on ultra-thin and highly flexible polydimethylsiloxane (PDMS) film substrates, only the composite structure film is transferred to deionized water or ethanol solution and heated to 80 degrees for reaction for 8 hours. The polyvinyl alcohol (PVA) film layer in the flexible composite structure can be dissolved and separated, and finally a flexible polydimethylsiloxane (PDMS) film with a device pattern is obtained in the solution, forming a flexible array electronic device with good sealing and packaging.

[0099] Example 4

[0100] Compared with Example 3, the only difference is that the complex device pattern is directly prepared according to the method of Example 1. During the experiment, it is found that the resolution of the device pattern is not as good as that of Example 3, and the yield rate decreases.

[0101] Comparative Example 1

[0102] Compared with Example 1, the only difference is that in step S5, the device pattern is transferred from a rigid substrate (silicon substrate) to a three-layer flexible composite structure (PET / PVA / PDMS) substrate by a direct mechanical peeling method. During the experiment, it is found that the device pattern will undergo large deformation during the peeling process and cannot be effectively transferred.

[0103] Obviously, the above embodiments are only examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for transferring a device pattern, characterized in that: The steps include: S1, preparing a rigid substrate, and preparing a device pattern on the surface of the rigid substrate; S2, spin coating a flexible substrate material layer on the surface of the rigid substrate having the device pattern so that the flexible substrate material layer is in an uncured state; S3, preparing a polyethylene terephthalate film, and preparing a water-soluble organic binder layer on one surface of the polyethylene terephthalate film, wherein the size of the water-soluble organic binder layer is smaller than the size of the flexible substrate material layer; S4, covering the water-soluble organic binder layer on the flexible substrate material layer in S2, and curing; S5, peeling off the rigid substrate with the aid of alkali solution to obtain a composite structure film, thereby achieving the transfer of the device pattern.

2. The device pattern transfer method according to claim 1, characterized in that: In S2, the flexible substrate material layer comprises an organic polymer solution and a curing agent in a mass ratio of 8:1 to 11:1, wherein the organic polymer in the organic polymer solution comprises one of polydimethylsiloxane, polyimide and polyurethane; And / or, the spin coating thickness of the flexible substrate material layer is 20 micrometers to 200 micrometers.

3. The device pattern transfer method according to claim 1, characterized in that: In S3, the step of preparing the water-soluble organic binder layer includes: preparing a water-soluble organic binder aqueous solution with a mass concentration of 5% to 10%, coating it on the surface of the polyethylene terephthalate film, and heating it to obtain the water-soluble organic binder layer; And / or, in S3, the polyethylene terephthalate film has a thickness of 100 μm to 300 μm.

4. The device pattern transfer method according to claim 3, characterized in that: In S3, the heating temperature is 40°C to 60°C, and the heating time is 15min to 60min; and / or, the thickness of the water-soluble organic binder layer is 10 microns to 100 microns; And / or, the water-soluble organic binder includes at least one of polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, starch and its derivatives, sodium alginate or polyethylene oxide.

5. The device pattern transfer method according to claim 1, characterized in that: In S4, the curing temperature is 60° C. to 120° C., and the curing time is 8 hours to 24 hours.

6. The device pattern transfer method according to claim 1, characterized in that: In S5, the parameters of the alkali solution assisted stripping include: a heating temperature of 40°C to 80°C and a heating time of 4 hours to 12 hours; And / or, the concentration of the alkali solution is below 2000mmol / L.

7. A method for preparing a flexible electronic device, characterized in that: The steps include: S11, obtaining a composite structure film according to the device pattern transfer method according to any one of claims 1 to 6; S12, separating the polyethylene terephthalate film from the flexible substrate to obtain a flexible electronic device.

8. The method for preparing a flexible electronic device according to claim 7, characterized in that: The step of separating the polyethylene terephthalate film from the flexible substrate comprises: immersing the composite structure film in water or ethanol aqueous solution and heating at 70° C. to 90° C. for 8 to 12 hours.

9. A flexible electronic device prepared by the preparation method according to any one of claims 7 to 8.

10. Application of the flexible electronic device according to claim 9 in the fields of wearable devices, smart medical treatment or smart home.

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