Preparation method of flexible film and flexible electronic device

Abstract

The invention provides a preparation method of a flexible thin film and a flexible electronic device, and the method comprises the steps: depositing a metal thin film on the surface of a preset flexible substrate, and depositing an oxide layer on the metal thin film, so as to form a coated metal layer; uniformly coating the reverse photoresist on the surface of the coated metal layer in a rotary gluing manner so as to form a gluing layer on the surface of the coated metal layer; photoetching and developing the gluing layer to form a developing part, wherein the gluing layer of the developing part is distributed in a preset pattern; performing etching treatment on the developing part to form an etching part, wherein the etching part comprises a flexible substrate, and a coating metal layer and a gluing layer which are positioned on the flexible substrate and are distributed in a preset pattern; and sequentially carrying out dry-method photoresist removal and wet-method photoresist removal on the etched part, and removing the glue coating layer on the coated metal layer to form the flexible thin film. The preparation process of the flexible thin film can be improved, and application and characterization of the flexible thin film are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible electronic preparation processes, and more specifically, to a flexible film and a flexible electronic device. Background Art

[0002] In recent years, with the continuous development of wearable smart technology, flexible electronic devices have entered the public eye more and more. The degumming process of traditional electronic devices is usually carried out on a rigid substrate, whose surface is relatively flat, and a stronger degumming process can be used, such as direct ultrasound, plasma degumming or N-methylpyrrolidone solution (NMP) immersion degumming.

[0003] However, compared to rigid electronic devices, flexible electronic devices must be fabricated on flexible substrates, and photolithography processes on flexible substrates are more challenging. For example, the mismatch in thermal expansion coefficients between the flexible substrate and the photoresist can lead to an uneven interface, which in turn reduces the processing accuracy of the material. In addition, the organic solutions involved in the process can also damage the flexible substrate to a certain extent, thereby affecting the deformation ability of the flexible film. At the same time, for special substrate materials, such as organic flexible substrates, the accumulation of high temperatures after etching can easily cause the photoresist to denature and carbonize. The carbonized photoresist cannot be removed by conventional chemical solutions, thus affecting the subsequent preparation and characterization of the film.

[0004] Therefore, there is an urgent need to provide a flexible film that can optimize its preparation process and improve the debonding efficiency and debonding quality during the process. Summary of the Invention

[0005] In view of the above problems, the present invention provides a method for preparing a flexible film and a flexible electronic device to solve the problems of difficulty in removing glue during the preparation of existing flexible films, which leads to complicated film preparation process, high cost and poor quality.

[0006] The method for preparing a flexible film provided by the present invention includes: depositing a metal film on the surface of a preset flexible substrate, and depositing an oxide layer on the metal film to form a coated metal layer; uniformly coating the surface of the coated metal layer with a reverse photoresist by spin coating to form a coating layer on the surface of the coated metal layer; performing photolithography and development on the coating layer to form a developing part, wherein the coating layer of the developing part is distributed in a preset pattern; performing etching on the developing part to form an etched part, wherein the etched part includes the flexible substrate and the coated metal layer and the coating layer located on the flexible substrate and distributed in the preset pattern; and sequentially performing dry stripping and wet stripping on the etched part to remove the coating layer on the coated metal layer to form the flexible film.

[0007] In addition, an optional technical solution is that the material of the flexible substrate is polyimide; the metal film is deposited on the flexible substrate by a PVD or PLD process, and the material of the metal film includes Ni, Co and Fe.

[0008] In addition, an optional technical solution is to perform a pre-baking treatment on the adhesive layer before performing photolithography and development treatment on the adhesive layer; wherein the pre-baking treatment includes: placing the adhesive layer on a heating table at a temperature of 90-95°C for a heating time of 100-120s.

[0009] In addition, an optional technical solution is that when the metal film is deposited by PVD, the PVD method is magnetron sputtering; the parameters of the magnetron sputtering are: sputtering vacuum is 2.5×10 -3 -3.5×10 -3 Torr, gas flow rate is 25-30sccm, sputtering power is 60-70w, sputtering rate is 3-3.2nm / min, and sputtering thickness is 120-130nm.

[0010] In addition, an optional technical solution is that the flexible substrate is vacuum adsorbed on a glue spreader; the glue spreader rotates at a speed of 3500-4000 r / min, and the glue spreading duration is 30-35 s; or, the glue spreading speed is 10000-12000 r / min, and the glue spreading duration is 1-2 s.

[0011] In addition, an optional technical solution is to perform photolithography and development on the coating layer, after the coating layer is photolithographically exposed, immerse it in a developing solution for development treatment, the exposure time of the photolithographic exposure is 5-5.5s, and the development treatment time is 45-55s; then, the structural parts after the development treatment are immersed in deionized water for cleaning, and finally blown dry with nitrogen.

[0012] In addition, an optional technical solution is that the process of etching the developing part includes: placing the developing part in an ion beam etcher with nitrogen and argon, and the working pressure of the ion etcher is 2.1×10 -2 -2.2×10 - 2 Pa, the sputtering beam current is 68-75mA, and the etching time is 8-10min.

[0013] In addition, an optional technical solution is that the dry degumming process includes: using a plasma cleaning machine to process the etched part, the power of the plasma cleaning machine is 200W, the cleaning liquid is 100% O2, and the cleaning time is 10 minutes; after the etched part is cleaned, wait for 2-3 minutes, and then put the etched part into the plasma cleaning machine for the second operation, and the total cleaning time is 20 minutes.

[0014] In addition, an optional technical solution is that the wet degumming process includes: placing the structural parts after dry degumming treatment in an acetone solution for ultrasonic treatment, and the ultrasonic time is 30-45s; soaking the structural parts after ultrasonic treatment in isopropyl alcohol or ethanol for cleaning, and finally blowing them dry with nitrogen to form the flexible film.

[0015] On the other hand, the present invention further provides a flexible electronic device, comprising a flexible film prepared by the above-mentioned method for preparing a flexible film.

[0016] By utilizing the above-mentioned method for preparing a flexible film and a flexible electronic device, a metal film can be deposited on the surface of a flexible substrate and subjected to photolithography; a reverse photoresist is uniformly coated on the surface of the coated metal layer by spin coating to form a coating layer on the surface of the coated metal layer; the coating layer is subjected to photolithography and development to form a developer, the coating layer of the developer being distributed in a preset pattern; the developer is etched to form an etched part, the etched part including a flexible substrate and a coated metal layer and a coating layer located on the flexible substrate and distributed in a preset pattern; the etched part is sequentially subjected to dry and wet stripping to remove the coating layer on the coated metal layer to form a flexible film.

[0017] In order to achieve the above and related purposes, one or more aspects of the present invention include the features that will be described in detail later. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all of these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By referring to the following description in conjunction with the accompanying drawings, and with a more complete understanding of the present invention, other objects and results of the present invention will become more clear and easy to understand. In the accompanying drawings:

[0019] Figure 1 is a flow chart of a method for preparing a flexible film according to an embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of a flexible substrate according to an embodiment of the present invention;

[0021] Figure 3A schematic diagram of a structure formed by a metal film according to an embodiment of the present invention;

[0022] Figure 4 A schematic structural diagram of a photoresist according to an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of a structure after photolithography development according to an embodiment of the present invention;

[0024] Figure 6 is a schematic diagram of the structure after etching according to an embodiment of the present invention;

[0025] Figure 7 Schematic diagram of the structure after smooth dry and wet degumming according to the present invention;

[0026] The symbols in the drawings include: flexible substrate 1 , metal film 2 , and photoresist 3 .

[0027] The same reference numerals throughout the drawings indicate similar or corresponding features or functions. DETAILED DESCRIPTION

[0028] In the following description, for illustrative purposes, numerous specific details are set forth to provide a comprehensive understanding of one or more embodiments. However, it will be apparent that the embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate description of one or more embodiments.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0030] In order to solve the problem that carbonized photoresist caused by high temperature accumulation during etching of a flexible film cannot be removed, and at the same time, different from the traditional rigid substrate stripping process, simple dry stripping may cause reactant contamination and residual photoresist impurities, while simple wet etching cannot remove the carbonized photoresist, the present invention provides a method for preparing a flexible film and a flexible electronic device, combining the advantages of dry stripping and wet stripping. The method first uses an oxygen plasma stripper to treat the surface, utilizes oxygen plasma to ionize oxygen to form oxygen atoms, which react chemically with the carbonized layer of the photoresist to produce carbon monoxide, carbon dioxide and water, which are then removed by vacuum to complete the dry stripping process. Subsequently, ultrasonic cleaning is performed at room temperature with an acetone solvent to accelerate the dissolution of remaining impurities and photoresist, completing the wet stripping process. The method can effectively remove the photoresist on the surface of the flexible film, optimize the preparation process of the flexible film, improve the stripping efficiency and quality, and is more conducive to the subsequent preparation and characterization of flexible electronic devices.

[0031] To describe in detail the method for preparing the flexible film and the flexible electronic device of the present invention, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Figure 1 A flow chart of a method for preparing a flexible film according to an embodiment of the present invention is shown.

[0033] like Figure 1 As shown, the method for preparing the flexible film according to an embodiment of the present invention includes:

[0034] S100: depositing a metal film on a surface of a preset flexible substrate, and depositing an oxide layer on the metal film to form a coated metal layer.

[0035] Specifically, the material of the flexible substrate can be polyimide, and when depositing a metal film thereon, a PVD or PLD process can be used. The material of the metal film can be Ni, Co, Fe, etc., and can be flexibly selected according to product requirements; in addition, in order to prevent the metal film from undergoing an oxidation reaction before the next process, which affects the quality and characterization of subsequent processes, an oxide layer can be further deposited on the side of the metal film away from the flexible substrate, and the metal film is preliminarily protected by the oxide layer, thereby completing the coating process on the flexible substrate. The above-mentioned coated metal layer can also be referred to as a metal film.

[0036] In a specific embodiment of the present invention, when the metal film is deposited by PVD, the PVD method can be magnetron sputtering. The parameters of magnetron sputtering include: sputtering vacuum of 2.5×10 -3 -3.5×10 -3Torr, gas flow rate is 25-30sccm, sputtering power is 60-70w, sputtering rate is 3-3.2nm / min, sputtering thickness is 120-130nm. This deposition method can improve the deposition process of metal films and achieve a deposition effect with controllable thickness.

[0037] S200: uniformly coating the reverse photoresist on the surface of the plated metal layer by spin coating to form a coating layer on the surface of the plated metal layer.

[0038] Specifically, in this step, AZ-5214 can be used to flip the photoresist, and only the positive photoresist process can be used to evenly coat the photoresist on the metal film by spin coating. As an example, the vacuum adsorption function of the glue spreader can be used to adsorb and fix the flexible substrate on the glue spreader, and then the glue coating parameters of the glue spreader can be controlled to achieve uniform coating of the photoresist, wherein the glue coating parameters include: the glue spreader rotation speed is 3500-4000r / min, and the glue coating duration is: 30-35s; or, the glue coating speed is 10000-12000r / min, and the glue coating duration is 1-2s.

[0039] S300: performing photolithography and development processing on the adhesive layer to form a development piece, wherein the adhesive layer of the development piece is distributed in a preset pattern.

[0040] Specifically, a contact photolithography machine is used for exposure, and then the sample (i.e., the structural component formed after the previous process) is immersed in a developing solution for development, and then immersed in deionized water for cleaning, and finally, after cleaning is completed, it is blown dry with nitrogen.

[0041] In a specific embodiment of the present invention, the photolithography exposure time of the photolithography machine can be set to 5-5.5s, and the development processing time can be set to 45-55s.

[0042] It should be noted that before executing step S300, a pre-baking treatment of the coating layer may also be included, wherein the pre-baking treatment includes: placing the coating layer on a heating table at a temperature of 90-95°C and a heating time of 100-120s. Through this pre-baking treatment, the adhesion effect between the photoresist and the metal film can be better. At the same time, controlling the pre-baking temperature within the range of 90-95°C can prevent the flexible substrate from expanding and warping due to high temperature, thereby ensuring the quality of photolithography and development processing.

[0043] S400: etching the developing member to form an etched member, wherein the etched member includes a flexible substrate and a plated metal layer and a glue layer located on the flexible substrate and distributed in a preset pattern.

[0044] Specifically, the structure after photolithography and development (also called developed part) is placed in an ion beam etcher with nitrogen and argon gas. The working pressure of the ion etcher is 2.1×10 -2 -2.2×10 -2 Pa, the sputtering beam current is 68-75 mA, and the etching time is 8-10 min, thereby forming a metal film distributed in a preset pattern on the flexible substrate, that is, a coated metal layer and a corresponding adhesive layer.

[0045] S500: performing dry and wet stripping on the etched part in sequence to remove the adhesive layer on the coated metal layer to form a flexible film.

[0046] Among them, the dry degumming process in this step includes: using a plasma cleaning machine to treat the etched parts, the power of the plasma cleaning machine is 200W, the cleaning liquid is 100% O2, and the cleaning time is 10 minutes; after the etched parts are cleaned, wait for 2-3 minutes, and then put the etched parts into the plasma cleaning machine for the second operation. The total cleaning time is 20 minutes.

[0047] The wet degumming process includes: placing the structural parts after dry degumming in an acetone solution for ultrasonic treatment for 30-45 seconds; soaking the ultrasonically treated structural parts in isopropyl alcohol or ethanol for cleaning, and finally blowing them dry with nitrogen to form a flexible film.

[0048] The flexible film preparation method of the present invention overcomes the limitations of existing processes such as photolithography and stripping on rigid silicon wafers, as well as the defect that dry etching can only be performed after coating a flexible substrate, but residues are not completely removed, affecting subsequent characterization. By combining dry and wet stripping, the cumulative stripping time is controlled within 30-40 minutes, significantly improving the stripping efficiency and quality, greatly reducing the preparation cost of the flexible film, and being applicable to various types of flexible film preparation scenarios with different requirements.

[0049] As a specific example, Figure 7 A schematic diagram showing the principle of a method for preparing a flexible film according to an embodiment of the present invention is shown.

[0050] like Figures 2 to 7 As shown together, the method for preparing the flexible film according to the embodiment of the present invention includes:

[0051] 1. Select polyimide film as flexible substrate 1 and complete substrate preparation, such as Figure 2 As shown;

[0052] 2. Based on the heat resistance of polyimide material (280-380℃), a metal film 2 is deposited on the surface of the flexible substrate 1 using PVD or PLD process to complete the coating. The formed metal film 2 is as follows: Figure 3 As shown;

[0053] 3. Use AZ-5214 reverse photoresist (only positive photoresist process) to evenly coat the photoresist 3 on the surface of the metal film 2 by spin coating. Figure 4 As shown;

[0054] 4. Place the flexible substrate 1 with the photoresist 3 on a heating table at 90-95 degrees and bake for 100-120 seconds. This pre-baking step allows the photoresist 3 to better adhere to the metal film 2 and prevents the flexible substrate 1 from warping due to thermal expansion.

[0055] 5. Photolithography and development: Use a contact photolithography machine to expose, then immerse the sample formed in the previous step in a developer solution for development, then soak it in deionized water for cleaning, and finally blow it dry with nitrogen. Figure 5 As shown;

[0056] 6. Etching: The structure after photoresist stripping is further placed in the AD-IBE150 ion beam etcher for physical etching in dry etching. The etching rate is controlled by adjusting the argon ion energy and beam current to form Figure 6 The etched structure shown.

[0057] It should be noted that, during the above-mentioned photolithography and development process, a preset pattern shape can be formed according to a set program, and the specific distribution or shape of the metal film 2 can be flexibly set according to demand and is not limited to the structure shown in the drawings.

[0058] 7. Dry degumming: Use a plasma cleaning machine to process the sample from the previous step, set the power to 200W, and the cleaning time to 10 minutes. After cleaning, wait for 2-3 minutes before placing the sample into the plasma cleaning machine for the second operation. The total time is 20 minutes.

[0059] 8. Wet degumming: Place the plasma-cleaned sample in an acetone solution for ultrasonic treatment for 30-45 seconds, then soak it in isopropyl alcohol or ethanol for cleaning, and finally blow it dry with nitrogen to complete the preparation process of the flexible film.

[0060] Corresponding to the above-mentioned method for preparing a flexible film, the present invention further provides a flexible electronic device, comprising a flexible film prepared by the above-mentioned method for preparing a flexible film.

[0061] It should be noted that the embodiments of the flexible electronic device can refer to the description in the embodiment of the method for preparing the flexible film, which will not be described in detail here.

[0062] According to the above-mentioned flexible film preparation method and flexible electronic device of the present invention, the advantages of dry stripping and wet stripping can be effectively combined. The surface is treated with an oxygen plasma stripper, so that the oxygen plasma ionizes oxygen to form oxygen atoms, which react chemically with the carbonized layer of the photoresist to produce carbon monoxide, carbon dioxide, and water, etc., which are then removed by vacuum to complete the dry stripping process. Thereafter, ultrasonic cleaning is performed at room temperature with acetone solvent to accelerate the dissolution of remaining residual impurities and photoresist, completing the wet stripping process. The photoresist on the surface of the flexible film can be effectively removed, thereby optimizing the preparation process of the flexible film, improving the stripping efficiency and quality, and at the same time being beneficial to the subsequent preparation and characterization of flexible electronic devices, thereby improving the processing accuracy and quality of flexible electronic devices.

[0063] The flexible film preparation method and flexible electronic device according to the present invention are described above by way of example with reference to the accompanying drawings. However, those skilled in the art will appreciate that various modifications may be made to the flexible film preparation method and flexible electronic device described above without departing from the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a flexible film, characterized in that: include: Depositing a metal film on a surface of a predetermined flexible substrate, and depositing an oxide layer on the metal film to form a coated metal layer; Uniformly coating the reverse photoresist on the surface of the plated metal layer by spin coating to form a coating layer on the surface of the plated metal layer; Performing photolithography and development processing on the adhesive layer to form a developing piece, wherein the adhesive layer of the developing piece is distributed in a preset pattern; Etching the developing member to form an etched member, wherein the etched member includes the flexible substrate and a plated metal layer and a glue layer located on the flexible substrate and distributed in the preset pattern; The etched part is sequentially subjected to dry and wet degumming to remove the adhesive layer on the plated metal layer, so as to form the flexible film.

2. The method for preparing a flexible film according to claim 1, wherein: The material of the flexible substrate is polyimide; The metal film is deposited on the flexible substrate by a PVD or PLD process, and the material of the metal film includes Ni, Co and Fe.

3. The method for preparing a flexible film according to claim 1, wherein: Before the coating layer is subjected to photolithography and development, the coating layer is subjected to pre-baking treatment; wherein, The pre-baking treatment includes: placing the adhesive layer on a heating table at a temperature of 90-95° C. for a heating time of 100-120 seconds.

4. The method for preparing a flexible film according to claim 2, wherein: When the metal film is deposited by PVD, the PVD method is magnetron sputtering; The parameters of the magnetron sputtering are: sputtering vacuum is 2.5×10 -3 -3.5×10 -3 Torr, gas flow rate is 25-30sccm, sputtering power is 60-70w, sputtering rate is 3-3.2nm / min, and sputtering thickness is 120-130nm.

5. The method for preparing a flexible film according to claim 1, wherein: The flexible substrate is vacuum-adsorbed on a coating machine; The speed of the glue spreading machine is 3500-4000 r / min, and the glue spreading duration is 30-35 s; or the speed of the glue spreading machine is 10000-12000 r / min, and the glue spreading duration is 1-2 s.

6. The method for preparing a flexible film according to claim 1, wherein: During the process of photolithography and development of the coating layer, After the coating layer is subjected to photolithographic exposure, it is immersed in a developing solution for development treatment, wherein the exposure time of the photolithographic exposure is 5-5.5 seconds, and the development treatment time is 45-55 seconds; Then, the developed structural component is immersed in deionized water for cleaning, and finally blown dry with nitrogen.

7. The method for preparing a flexible film according to claim 1, wherein: The process of etching the developing member includes: The developing part is placed in an ion beam etcher with nitrogen and argon gas. The working pressure of the ion etcher is 2.1×10 -2 -2.2×10 -2 Pa, the sputtering beam current is 68-75mA, and the etching time is 8-10min.

8. The method for preparing a flexible film according to claim 1, wherein: The dry degumming process includes: The etched part is treated with a plasma cleaning machine, wherein the power of the plasma cleaning machine is 200W, the cleaning liquid is 100% O2, and the cleaning time is 10 minutes; After the etched part is cleaned, wait for 2-3 minutes, then put the etched part into the plasma cleaning machine for the second operation. The total cleaning time is 20 minutes.

9. The method for preparing a flexible film according to claim 1, wherein: The wet stripping process includes: The structural parts after dry degumming treatment are placed in acetone solution for ultrasonic treatment, and the ultrasonic time is 30-45s; The ultrasonically treated structural component is soaked in isopropyl alcohol or ethanol for cleaning, and finally dried with nitrogen gas to form the flexible film.

10. A flexible electronic device, characterized in that: The invention comprises a flexible film prepared by the method for preparing a flexible film according to any one of claims 1 to 9.

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