Method for manufacturing layered structure and method for manufacturing electronic device

Abstract

To manufacture a layered structure equipped with a layer including a carbon nano-tube with good productivity.SOLUTION: A layered structure manufacturing comprises first to fifth steps. In the first step, a first coating liquid having a dispersoid containing a carbon nano-tube and a liquid as a dispersant in which the dispersoid is dispersed is applied to a principal surface of a base plate. In the second step, the first coating liquid applied to the principal surface is dried. In the third step, the liquid is removed being modified, and a first layer containing the dispersoid is formed. In the fourth step, a second coating liquid containing a precursor of a high polymeric material is applied to the first layer from a side opposite to the principal surface. In the fifth step, the precursor is polymerized, and a second layer containing the high polymeric material is formed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to methods of manufacturing layered structures and methods of manufacturing electronic devices. [Background technology]

[0002] Lightweight and flexible electronic devices, such as display devices typified by liquid crystal displays and organic electroluminescence (EL) displays, are desirable. For example, a plastic film (e.g., a polyimide film) is formed on a carrier substrate (e.g., a glass substrate) that serves as a base material, a thin-film-transistor (TFT) circuit is formed on this plastic film, and the carrier substrate is then peeled off from the plastic film. The electronic device obtained in this manner is lightweight and flexible.

[0003] Patent Document 1 exemplifies methods for peeling a carrier substrate from a plastic film, including a method of peeling by immersion treatment, a method of peeling using a laser, and a method of peeling by forming an adhesive layer between the carrier substrate and the plastic film.

[0004] Patent Document 2 discloses a technique for peeling a polyimide film from a glass substrate without using a laser. Patent Document 2 exemplifies a structure in which a peeling layer containing carbon nanotubes is provided between a glass substrate, which is a carrier substrate, and a polyimide film, which is a plastic film. Patent Document 2 discloses a technique for forming a peeling layer by applying a dispersion liquid containing carbon nanotubes as a dispersoid to a glass substrate and evaporating the dispersion medium of the dispersion liquid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-165491 [Patent Document 2] Japanese Patent Application Publication No. 2019-144347 Summary of the Invention [Problem to be solved by the invention]

[0006] In laser-based peeling, the surface of the plastic film facing the carrier substrate is burned with a laser, and then the plastic film is mechanically pulled and peeled off from the carrier substrate. This technique is called the EPLaR (Electronics on Plastic by Laser Release) method. In the EPLaR method, a high-power laser severely damages the plastic film, such as a polyimide film. This damage generates stress in the plastic film. This stress causes the plastic film to deform as if it were being rolled up after peeling. This deformation can damage the circuits formed on the plastic film. The EPLaR method requires expensive laser annealing equipment.

[0007] Patent Document 2 discloses the formation of a release layer, but does not disclose details about improving the efficiency when forming the release layer.

[0008] The present disclosure provides a technique for productively manufacturing a layered structure having a layer containing carbon nanotubes. [Means for solving the problem]

[0009] Method for manufacturing a layered structure according to the present disclosure The first aspect of The method includes a first step of applying a first coating liquid containing a dispersoid containing carbon nanotubes and a liquid that is a dispersion medium in which the dispersoid is dispersed onto a main surface of a substrate, and a second step of drying the first coating liquid applied onto the main surface. At least a portion of the dispersion medium is reduced. a second step, a third step of removing the liquid while modifying it to form a first layer containing the dispersoid, a fourth step of applying a second coating liquid containing a precursor of a polymer material to the first layer from the side opposite to the main surface, and a fifth step of polymerizing the precursor to form a second layer containing the polymer material. In the third step, oxygen radicals are supplied to the liquid, and in the third step, the oxygen radicals are generated using oxygen plasma. . A second aspect of the method for manufacturing a layered structure according to the present disclosure includes a first step of applying a first coating liquid containing a dispersoid including carbon nanotubes and a liquid that is a dispersion medium in which the dispersoid is dispersed to a main surface of a substrate; a second step of drying the first coating liquid applied to the main surface to reduce at least a portion of the dispersion medium; a third step of removing the liquid while modifying it to form a first layer containing the dispersoid; a fourth step of applying a second coating liquid containing a precursor of a polymer material to the first layer from the side opposite the main surface; and a fifth step of polymerizing the precursor to form a second layer containing the polymer material, wherein in the third step, reactive plasma is generated on the side of the liquid opposite the main surface. [Effects of the Invention]

[0010] It is easy to form a structure on the side opposite the main surface of the second layer because the substrate serves as a support layer during the formation of the structure, and after the structure is formed, it is easy to separate the substrate from the second layer. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a flowchart illustrating a manufacturing process for an electronic device. [Figure 2] FIG. [Figure 3] FIG. 2 is a side view showing a state in which a release layer is formed on a substrate. [Figure 4] FIG. 2 is a side view showing a state in which a polyimide layer is formed on a release layer. [Figure 5] FIG. 2 is a plan view showing a state in which a polyimide layer is formed on a release layer. [Figure 6] FIG. 10 is a cross-sectional view showing a state in which a barrier layer is formed on a polyimide layer. [Figure 7] FIG. 2 is a plan view showing a state in which a barrier layer is formed on a polyimide layer. [Figure 8] FIG. 10 is a cross-sectional view showing a state in which a circuit layer is formed on a barrier layer. [Figure 9] 10A to 10C are cross-sectional views illustrating a step of peeling off the laminate from the substrate. [Figure 10] 1 is a flowchart illustrating the formation of a release layer. [Figure 11] FIG. 10 is a side view schematically showing an aspect in which ultraviolet light is irradiated while the substrate is being moved. [Figure 12] FIG. 10 is a side view schematically showing an embodiment in which ultraviolet light is irradiated without moving the substrate. [Figure 13] 10 is a flowchart showing another example of forming a release layer. [Figure 14] FIG. 2 is a side view schematically showing the generation of reactive plasma. DETAILED DESCRIPTION OF THE INVENTION

[0012] <1. Overall explanation of the manufacturing process of electronic devices> Fig. 1 is a flow chart illustrating a manufacturing process of an electronic device, such as a display device. Fig. 2 is a side view of a substrate 10, viewed from a direction perpendicular to its thickness direction.

[0013] Step S10 is a process of preparing a substrate 10. The substrate 10 has a smooth main surface 10a. For example, plate-shaped glass is used for the substrate 10. The substrate 10 has a surface 10b that faces the main surface 10a in the thickness direction. The thickness direction can be said to be a direction perpendicular to the main surface 10a. In Figures 1 to 8, direction P is the direction from the main surface 10a to the surface 10b in the thickness direction of the substrate 10.

[0014] There are no particular limitations on the shape or size of the substrate 10 when viewed from a plane along the direction P. For example, the substrate 10 has a rectangular shape when viewed from a plane. The plan view corresponds to a view from a direction perpendicular to the main surface 10a.

[0015] The substrate 10 functions as a carrier substrate for holding and transporting the polyimide layer 30 and the circuit layer 50 (and / or the barrier layer 40) described below during the manufacturing process of the electronic device. The substrate 10 does not remain in the electronic device as a final product.

[0016] By using the substrate 10 as a carrier substrate, the flexible polyimide layer 30 is stably held, and the circuit layer 50 can be easily formed on this polyimide layer 30. Using the substrate 10 as a carrier substrate makes it easy to manufacture electronic devices using existing manufacturing equipment (e.g., coating equipment, heat treatment equipment) for forming circuit layers on general substrates.

[0017] Step S11 is a process of applying the first coating liquid 102 onto the substrate 10 prepared in step S10. Here, "on the substrate 10" is synonymous with "on the main surface 10a." The first coating liquid 102 is applied to the main surface 10a by a known method, for example, a slit coating method.

[0018] In the slit coating method, for example, a slit coater is used. The slit coater, for example, scans a slit nozzle that ejects a first coating liquid 102 as a coating liquid at a constant speed across a substrate 10 that is held stationary. By controlling the coating range of the coating liquid, the first coating liquid 102 is contained within the main surface 10a of the substrate 10 in a plan view. Figure 3 is a side view showing the state in which the first coating liquid 102 has been coated onto the substrate 10.

[0019] A process for cleaning the main surface 10a may be performed between steps S10 and S11. Examples of such a process include chemical cleaning, which cleans the main surface 10a with a chemical solution, brush cleaning, which mechanically removes contaminants from the main surface 10a with a brush, and a process of irradiating the main surface 10a with ultraviolet light to decompose and remove contaminants.

[0020] The first coating liquid 102 is a dispersion and includes a dispersoid and a liquid to be dispersed. In the manufacturing method according to the present disclosure, the dispersoid includes carbon nanotubes. The liquid to be dispersed includes a dispersion medium, in which the dispersoid is dispersed. As the dispersion medium, either or both of an aqueous liquid and an organic liquid are used. The liquid to be dispersed may further include a dispersant. Examples of dispersants include surfactants. The dispersant is not limited to a liquid, but may also be a solid.

[0021] Step S12 is a process for drying the first coating fluid 102 (hereinafter simply referred to as "drying process") in the drawings. Examples of this drying process include drying under reduced pressure and heating. This drying process reduces at least a portion of the dispersion medium in the first coating fluid 102.

[0022] Step S13 is a process for forming the release layer 20 from the first coating liquid 102 after the drying treatment. For example, step S13 is a process for removing the dispersion liquid while modifying it to form the release layer 20 containing dispersoids. Here, "modification" includes, as one aspect, decomposition of the dispersion liquid, and various aspects are exemplified below.

[0023] By removing the dispersion liquid, the release layer 20 is obtained as a paper-like material in which carbon nanotubes are entangled with each other. The paper-like material is a porous film formed from fibrous materials. Carbon nanotubes themselves are fibrous materials. By removing the dispersion liquid from the first coating liquid 102, a paper-like material in which fibrous carbon nanotubes are entangled with each other is formed. The film thickness of the release layer 20 is, for example, 100 nm or less.

[0024] Step S14 is a process of applying the second coating liquid 103 to the release layer 20. More specifically, the second coating liquid 103 is applied to the release layer 20 from the side opposite to the main surface 10a. The second coating liquid 103 is applied to the release layer 20 by a known method, for example, a slit coating method.

[0025] In this embodiment, in plan view, the second coating liquid 103 is contained within the main surface 10a while covering the release layer 20. The second coating liquid 103 is also applied to the main surface 10a around the release layer 20. In plan view, the second coating liquid 103 located outside the release layer 20 comes into contact with the main surface 10a.

[0026] Fig. 4 is a side view showing a state in which the second coating liquid 103 has been applied onto the release layer 20. In Fig. 4, an outer edge 20f of the release layer 20 in a plan view is shown.

[0027] Step S15 is a process for forming a polyimide layer 30 from the second coating fluid 103. For example, step S15 includes polymerization. The thickness of the polyimide layer 30 is approximately 10 μm.

[0028] The second coating fluid 103 contains a precursor of a polymer material, which in this embodiment is a polyimide precursor. Step S15 is a process of polymerizing the precursor to form a layer containing a polymer material, which in this embodiment is a polyimide layer 30. For example, in step S15, the second coating fluid 103 is heated together with the substrate 10 to 350°C or higher to be imidized. In step S15, for example, a heat treatment furnace is used. The heat treatment furnace heats the substrate 10 by blowing hot air.

[0029] 5 is a plan view showing a state in which the polyimide layer 30 is formed on the release layer 20. The peripheral portions of the four sides of the polyimide layer 30 that extend beyond the outer edge 20f of the release layer 20 are outside the outer edge 20f and contact the main surface 10a.

[0030] The release layer 20 is a porous film with a fibrous structure, and the second coating liquid 103 easily penetrates into the minute irregularities of the fibrous structure. The polyimide layer 30 obtained by polymerization has high adhesion to the release layer 20. The main surface 10a is smooth, and has low adhesion to the release layer 20. The peelability between the substrate 10 and the release layer 20 is higher than the peelability between the polyimide layer 30 and the release layer 20.

[0031] If the adhesion between the release layer 20 and the substrate 10 decreases, there is a concern that the release layer 20 may peel off from the substrate 10 during the manufacturing process of the display device. The polyimide layer 30 in the portion of the release layer 20 that is in contact with the main surface 10a outside the outer edge 20f of the release layer 20 has the function of preventing the release layer 20 from peeling off from the substrate 10 during the manufacturing process of the display device.

[0032] Step S40 is a process of forming a barrier layer 40 on the polyimide layer 30. Fig. 6 is a cross-sectional view showing a state in which the barrier layer 40 has been formed on the polyimide layer 30. Fig. 7 is a plan view showing a state in which the barrier layer 40 has been formed on the polyimide layer 30.

[0033] The barrier layer 40 is a layer for preventing moisture from penetrating into the circuit layer 50 described below, and is made of, for example, a silicon nitride (SiNx) film. The barrier layer 40 is formed by various known methods, such as a CVD method.

[0034] The barrier layer 40 is formed in a predetermined region R on the polyimide layer 30. The predetermined region R is surrounded by an outer edge 20f in plan view.

[0035] Step S16 is a process of forming a circuit layer 50 on the barrier layer 40. Fig. 7 is a plan view showing the circuit layer 50 formed on the barrier layer 40. Fig. 8 is a cross-sectional view showing the circuit layer 50 formed on the barrier layer 40. The barrier layer 40 is formed in a predetermined region R in a plan view, and the circuit layer 50 is also formed in the same manner.

[0036] For example, the circuit layer 50 has an electronic circuit including a thin film transistor. The circuit layer 50 is formed by a known array process that repeats steps such as film formation, photolithography, and etching. After the circuit layer 50 is formed, an organic EL layer and a sealing layer may be further formed.

[0037] Step S17 is performed after the circuit layer 50 is formed. Step S17 is a process of cutting the polyimide layer 30 and the release layer 20. Step S18 is performed after step S17 is performed. Step S18 is a process of peeling the substrate 10 from the release layer 20. Steps S17 and S18 can be collectively said to be a process of peeling the laminate 60 including the release layer 20, polyimide layer 30, barrier layer 40, and circuit layer 50 from the substrate 10.

[0038] 9 is a cross-sectional view illustrating steps S17 and S18, or the process of peeling laminate 60 from substrate 10. In step S17, polyimide layer 30 and release layer 20 are cut between outer edge 20f and predetermined region R. In step S18, laminate 60 is mechanically peeled off from substrate 10. The dashed lines in FIG. 9 indicate the positions where polyimide layer 30 and release layer 20 are cut, and show the positional relationship between peeled laminate 60 and polyimide layer 30 and release layer 20 remaining on substrate 10.

[0039] While the adhesion between the release layer 20 and the polyimide layer 30 is high, the adhesion between the release layer 20 and the substrate 10 is low. When the laminate 60 including the polyimide layer 30 is mechanically pulled, the interface between the release layer 20 and the substrate 10 is easily peeled off. Therefore, the polyimide layer 30 is easily peeled off from the substrate 10 while minimizing damage to the polyimide layer 30.

[0040] The laminate 60 after peeling has a structure in which an electronic circuit is formed on a thin polyimide substrate. Such a laminate 60 is used as a main component of a flexible device, such as a display device.

[0041] Because of the strong adhesion between the release layer 20 and the polyimide layer 30, the release layer 20 remains attached to the polyimide layer 30 in the laminate 60. The release layer 20 is, for example, a paper-like material with a film thickness of 100 nm or less, and does not interfere with the flexibility of the laminate 60. The release layer 20 may also function as a barrier layer.

[0042] Step S17 may be omitted in some cases. For example, when the area of the peripheral edge of the polyimide layer 30 that contacts the substrate 10 is small, the laminate 60 may simply be mechanically pulled to remove it from the substrate 10. This process is also applicable when the second coating liquid 103 is applied to the release layer 20 without exceeding the outer edge 20f, and the polyimide layer 30 does not contact the substrate 10.

[0043] In this embodiment, the release layer 20 is sandwiched between the substrate 10 and the polyimide layer 30. The release layer 20 has high adhesion to the polyimide layer 30 but low adhesion to the substrate 10. By mechanically pulling the polyimide layer 30, the polyimide layer 30 is easily peeled off from the substrate 10 together with the release layer 20. The release layer 20 functions as a debonding layer.

[0044] According to this embodiment, the polyimide layer 30 can be easily peeled off from the substrate 10 without using a laser or the like to burn off the polyimide layer 30. Since an expensive laser annealing device is not required, the polyimide layer 30 can be peeled off from the substrate 10 inexpensively.

[0045] According to the present embodiment, no laser is used to peel the polyimide layer 30, and therefore damage to the polyimide layer 30 when peeling the polyimide layer 30 from the substrate 10 is small. Therefore, stress is unlikely to be generated in the polyimide layer 30, causing deformation such as winding up of the polyimide layer 30, and mechanical damage to the circuit layer 50 on the polyimide layer 30 is also suppressed. Suppression of such deformation and damage contributes to an improvement in the manufacturing yield of devices using the laminate 60.

[0046] The carbon nanotubes contained in the release layer 20 are electrically conductive. This electrical conductivity contributes to suppressing static electricity generation when the polyimide layer 30 is peeled off from the substrate 10. The suppression of static electricity generation contributes to suppressing electrical damage to the circuit layer 50.

[0047] 2. Explanation of the manufacturing method of the layered structure Steps S11 to S15 can be considered as a method for manufacturing the following layered structure, in which the release layer 20 is exemplified as the first layer and the polyimide layer 30 is exemplified as the second layer.

[0048] Step S11 can be considered a first process of applying, onto the main surface 10a of the substrate 10, the first coating liquid 102, which contains dispersoids containing carbon nanotubes and a liquid into which the dispersoids will be dispersed.

[0049] Step S12 can be considered a second step in which the first coating fluid 102 applied to the main surface 10a is dried.

[0050] Step S13 can be said to be a third step in which the dispersion liquid is removed while being transformed to form a first layer containing dispersoids (release layer 20 in the above example).

[0051] Step S14 can be considered a fourth process in which the second coating fluid 103 containing a precursor of a polymer material (a polyimide precursor in the above example) is applied to the first layer from the side opposite to the main surface 10a.

[0052] Step S15 can be considered a fifth process in which the precursor is polymerized to form a second layer (polyimide layer 30 in the above example) containing a polymer material (polyimide in the above example).

[0053] It is easy to form a structure (circuit layer 50 in the above example) on the side of the second layer opposite to main surface 10a because substrate 10 serves as a support layer during the formation of the structure. After the structure is formed, substrate 10 can be easily separated from the second layer.

[0054] In the following, various methods will be mainly described in steps S12 and S13.

[0055] <2-1. Transformation of the dispersed liquid by light irradiation> 10 is a flowchart illustrating the content of step S13 (forming the release layer 20). In step S13a, light irradiation is performed, and in step S13b, a heat treatment is performed. After step S13b is performed, the process returns to the flowchart shown in FIG. 1 (specifically, the execution of step S14 begins).

[0056] Specifically, in step S13a, light having a wavelength of 300 nm or less (hereinafter referred to as "ultraviolet light") is irradiated onto the first coating liquid 102. Such light irradiation generates oxygen radicals in the vicinity of the first coating liquid 102. The first coating liquid 102 contains, for example, an organic substance in the dispersion medium contained in the dispersion liquid, or contains an organic substance in the dispersant that can be contained in the dispersion liquid, and the organic substance is a compound that mainly contains carbon, hydrogen, and oxygen.

[0057] Carbon atoms C, hydrogen atoms H, oxygen atoms O, and oxygen radicals O* are introduced, and the oxygen radicals O* decompose the organic matter as follows, producing carbon monoxide, carbon dioxide, and water. This decomposition is one aspect of the above-mentioned transformation. Carbon monoxide and carbon dioxide are removed as gases, and water is removed as a liquid or gas from the first coating fluid 102, leaving a dispersion medium containing carbon nanotubes on the main surface 10a.

[0058] [ka]

[0059] In this embodiment, examples of ultraviolet light sources include deep ultraviolet light emitting diodes, low-pressure mercury lamps, and excimer lamps. Low-pressure mercury lamps mainly emit light with a wavelength of 254 nm. Excimer lamps mainly emit light with a wavelength of 172 nm.

[0060] After the light irradiation in step S13a, step S13b is performed. In step S13b, heating is performed at, for example, 350° C. For example, after the first coating fluid 102 is irradiated with ultraviolet light of 1000 mJ per square centimeter using a low-pressure mercury lamp in step S13a, heating is performed at 350° C. for 30 minutes in step S13b.

[0061] Compared to removing the dispersion liquid by simply heating, modifying the dispersion liquid using oxygen radicals O* makes it easier to avoid high-temperature treatment. For example, without using oxygen radicals O*, removing the dispersion liquid requires heating to about 500°C. In contrast, using oxygen radicals O* requires a lower heating temperature, improving the efficiency of forming the release layer 20.

[0062] Step S13a may be accompanied by heating. For example, reduced pressure drying is employed in step S12, ultraviolet light irradiation is performed in step S13a accompanied by heating at a first temperature, and heat treatment is performed at a second temperature higher than the first temperature in step S13b.

[0063] For example, in step S12, a drying process is performed by heating, and then step S13a is performed without heating or while maintaining heating. Thereafter, step S13b is performed at a temperature higher than that of step S12. For example, in steps S12 and S13a, heating at 100 to 150°C is adopted.

[0064] The fact that the heat treatment in step S13b does not exceed 700° C. contributes to preventing the characteristics of the carbon nanotubes in the separation layer 20 from deteriorating.

[0065] Two modes are proposed for performing step S13a. Fig. 11 is a side view schematically showing a mode in which ultraviolet light is irradiated while the substrate 10 is moved. Fig. 12 is a side view schematically showing a mode in which ultraviolet light is irradiated without moving the substrate 10.

[0066] The excimer lamp 8 includes a plurality of lamp tubes 81. Each of the lamp tubes 81 extends along a direction M, which is drawn perpendicular to the paper surface. A plurality of the lamp tubes 81 are arranged side by side along a direction Q. The direction Q is not parallel to the direction M, and in this example, the direction Q is perpendicular to the direction M.

[0067] The substrate 10 coated with the first coating liquid 102 is placed so that its direction P is non-parallel to both directions M and Q. Here, the case where the direction P is perpendicular to the directions M and Q is illustrated. The substrate 10 is placed so that the first coating liquid 102 faces the excimer lamp 8.

[0068] 11, the substrate 10 moves along a direction Q. The substrate 10 is transported in the direction Q while its surface 10b is supported by a plurality of rollers 9 extending, for example, along a direction M. The rotation of the rollers 9 in the clockwise direction in the drawing contributes to the movement of the substrate 10 in the direction Q.

[0069] 11 requires a transport mechanism but requires a small number of lamp tubes 81. In the embodiment shown in Fig. 12, no transport mechanism is required but requires a large number of lamp tubes 81.

[0070] <2-2. Transformation of dispersed liquid by plasma> 13 is a flowchart illustrating another example of step S13. In step S13c, reactive plasma is generated, and in step S13d, a heating process is performed. After step S13d is performed, the process returns to the flowchart shown in FIG. 1 (specifically, the execution of step S14 begins).

[0071] The temperature of the heat treatment carried out in step S13d is, for example, 200° C. or higher. The fact that the heat treatment in step S13d is carried out at a temperature not exceeding 700° C. contributes to preventing the characteristics of the carbon nanotubes in the separation layer 20 from deteriorating.

[0072] In step S13c, reactive plasma is generated (hereinafter also expressed as "reactive plasma is generated") in the vicinity of the first coating fluid 102. Examples of reactive gases used to generate reactive plasma include an embodiment in which an oxidizing gas is used and an embodiment in which a reducing gas is used.

[0073] An example of an oxidizing gas is oxygen gas, and a mixed gas of oxygen gas and argon gas is used to generate reactive plasma. An example of a reducing gas is hydrogen gas, and a mixed gas of hydrogen gas and argon gas is used to generate reactive plasma. Since the generation of reactive plasma using these mixed gases is well known, details thereof will be omitted.

[0074] When oxygen gas is used to generate the reactive plasma, the generated oxygen plasma supplies oxygen radicals O* to the first coating fluid 102. Due to a chemical reaction similar to that caused by the above-described irradiation with ultraviolet light, the dispersion medium containing the carbon nanotubes is left on the main surface 10a.

[0075] When hydrogen gas is used to generate the reactive plasma, the generated hydrogen plasma supplies hydrogen radicals H* to the first coating fluid 102. The hydrogen radicals H* are introduced and decompose the organic matter to generate water as described below. This decomposition is one aspect of the above-mentioned transformation. The water is removed from the first coating fluid 102 as a liquid or gas, and the dispersion medium containing the carbon nanotubes is left on the main surface 10a.

[0076] [ka]

[0077] In organic matter, the bond energy of CH is 413 KJ / mol, the bond energy of OH is 463 KJ / mol, and the bond energy of C=O is 799 KJ / mol. The bond energy of C=O is greater than the bond energy of CH. Hydrogen radicals H* can also break bonds in organic matter, just like oxygen radicals O*.

[0078] Hydrogen has a lower interatomic dissociation energy than oxygen, making it easier to generate plasma discharge. Reactive plasma using hydrogen gas is more likely to generate a large amount of plasma than oxygen gas.

[0079] 14 is a side view schematically showing the generation of reactive plasma. Chamber 7 contains a pair of electrodes 83. A mixed gas 82 is supplied between the pair of electrodes 83. Mixed gas 82 is supplied from outside chamber 7, and here, an embodiment in which mixed gas 82 is supplied between the pair of electrodes 83 is illustrated.

[0080] In the above example, the mixed gas 82 is a mixed gas of argon gas and oxygen gas, or a mixed gas of argon gas and hydrogen gas. For example, atmospheric pressure plasma is used as the reactive plasma.

[0081] The substrate 10 coated with the first coating fluid 102 moves in the chamber 7 along the direction Q while directing the first coating fluid 102 toward the electrode 83. As in Figures 11 and 12, Figure 14 also illustrates a case where the direction Q is perpendicular to the direction P.

[0082] Substrate 10 is transported in direction Q while being supported by, for example, a plurality of rollers 9 at surface 10b. Each of rollers 9 extends along direction M, which is perpendicular to both directions P and Q. Rotation of roller 9 in the clockwise direction in the drawing contributes to movement of substrate 10 in direction Q.

[0083] The reactive plasma is generated in region J sandwiched between electrodes 83. Oxygen radicals O* or hydrogen radicals H* diffuse from region J toward substrate 10 and are supplied to first coating fluid 102. The reactive plasma is generated on the side of the dispersion liquid contained in first coating fluid 102 opposite main surface 10a.

[0084] As with irradiation with ultraviolet light, the modification of the dispersion liquid using oxygen radicals O* generated by reactive plasma using an oxidizing gas also makes it easier to omit high-temperature treatment compared to removing the dispersion liquid by simple heating. The same is true for the modification of the dispersion liquid using reactive plasma using a reducing gas. For example, when the dispersion liquid is modified and removed using reactive plasma, step S13d may be omitted.

[0085] Patent Document 2 discloses that a coating film formed by applying a dispersion liquid is dried to evaporate the dispersion medium, but does not specify a technique for removing the dispersant. When a dispersant is contained in the liquid to be dispersed, the dispersant can be removed while being modified by, for example, heating the first coating liquid 102 at a temperature of 500°C for about 30 minutes. Such a heat treatment can reduce the efficiency of forming the release layer 20. The modification exemplified in the embodiment requires a low temperature for the heat treatment, improving the efficiency of forming the release layer 20.

[0086] <3. Explanation of the manufacturing method of the electronic device> Steps S16, S17, and S18, in combination with steps S11 to S15 for fabricating a layered structure, can be considered to be a method for fabricating an electronic device having electronic circuits contained in the circuit layer 50.

[0087] The circuit layer 50 is formed on the second layer exemplified by the polyimide layer 30 and can be considered to be an example of a third layer having an electronic circuit. Step S16 can be considered to be a sixth step of forming the third layer exemplified by the circuit layer 50 on the second layer exemplified by the polyimide layer 30, for example, in a predetermined region R.

[0088] Step S17 can be considered to be a seventh step of cutting the first layer exemplified by the release layer 20 and the second layer exemplified by the polyimide layer 30 between the outer edge 20f and the predetermined region R in a plan view. In this case, step S18 can be considered to be an eighth step of peeling the substrate 10 from the first layer.

[0089] Alternatively, when step S17 is omitted, step S18 can be said to be the seventh step described above.

[0090] <Transformation> Although the embodiments of the present disclosure have been described above, various modifications other than those described above can be made to the present disclosure without departing from the spirit thereof. For example, the formation of the barrier layer 40 may be omitted, and the circuit layer 50 may be formed directly on the polyimide layer 30. [Industrial Applicability]

[0091] The above-described technique can be used to manufacture display devices such as organic EL displays and liquid crystal displays, for example, to manufacture flexible devices in which circuits are formed on a polyimide substrate. [Explanation of symbols]

[0092] 10 Substrate 10a Main surface 20 Peeling layer (first layer) 20f outer edge 30 Polyimide layer (second layer) 50 Circuit layer (3rd layer) 102 First coating liquid 103 Second coating liquid C carbon atom H hydrogen atom H* Hydrogen radical O oxygen atom O* oxygen radical P (perpendicular to the main surface) direction R Predetermined area S11 Step (1st process) S12 Step (2nd process) S13 Step (3rd process) S14 Step (4th process) S15 Step (5th process) S16 Step (6th process) S17 Step (7th process) S18 Step (8th step; 7th step)

Claims

1. a first step of applying a first coating liquid, which includes a dispersoid containing carbon nanotubes and a liquid serving as a dispersion medium in which the dispersoid is dispersed, onto a main surface of a substrate; a second step of drying the first coating liquid applied to the main surface to reduce at least a portion of the dispersion medium; a third step of removing the liquid while modifying it to form a first layer containing the dispersoids; a fourth step of applying a second coating liquid containing a precursor of a polymer material to the first layer from the side opposite to the main surface; a fifth step of polymerizing the precursor to form a second layer comprising the polymeric material; Equipped with In the third step, oxygen radicals are supplied to the liquid, The method for producing a layered structure, wherein in the third step, the oxygen radicals are generated using oxygen plasma.

2. A method for producing a substrate, comprising: a first step of applying a first coating liquid having a dispersoid containing carbon nanotubes and a liquid as a dispersion medium in which the dispersoid is dispersed onto a main surface of the substrate; a second step of drying the first coating liquid applied to the main surface to reduce at least a portion of the dispersion medium; a third step of removing the liquid while modifying it to form a first layer containing the dispersoids; a fourth step of applying a second coating liquid containing a precursor of a polymer material to the first layer from the side opposite to the main surface; a fifth step of polymerizing the precursor to form a second layer comprising the polymeric material; Equipped with In the third step, reactive plasma is generated on the side of the liquid opposite to the main surface.

3. The method for producing a layered structure according to claim 2 , wherein the reactive plasma is generated using an oxidizing gas as a reactive gas.

4. The method for producing a layered structure according to claim 2 , wherein the reactive plasma is generated using a reducing gas as a reactive gas.

5. The method for manufacturing a layered structure according to claim 1 , wherein in the fourth step, the second coating liquid is also applied to the main surface around the first layer.

6. 1. A method of manufacturing an electronic device having an electronic circuit, comprising: The method for manufacturing a layered structure according to any one of claims 1 to 4, comprising the first to fifth steps; a sixth step of forming a third layer having the electronic circuitry on the second layer; a seventh step of peeling the substrate from the first layer after the sixth step; A method for manufacturing an electronic device, comprising:

7. 1. A method of manufacturing an electronic device having an electronic circuit, comprising: The method for producing a layered structure according to claim 5 includes the first to fifth steps; a sixth step of forming a third layer having the electronic circuit on the second layer in a predetermined region surrounded by an outer edge of the first layer when viewed in a direction perpendicular to the main surface; a seventh step, after the sixth step, of cutting the first layer and the second layer along the direction at a position between an outer edge of the first layer and the predetermined region as viewed from the direction; an eighth step of peeling the substrate from the first layer after the seventh step; A method for manufacturing an electronic device, comprising:

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