JP7719711B2 - Method for manufacturing layered structure and method for manufacturing electronic device - Google Patents

Description

The present disclosure relates to methods for manufacturing layered structures and methods for manufacturing electronic devices.

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 the base material. A TFT (thin-film-transistor) circuit is then 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.

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

Patent Document 2 discloses a technology 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 serves as a carrier substrate, and a polyimide film, which serves as a plastic film. Patent Document 2 discloses a technology 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.

JP 2015-165491 A Japanese Patent Application Laid-Open No. 2019-144347

In laser-based peeling methods, for example, 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 causes severe damage to 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.

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

This disclosure provides a technology for highly productively manufacturing layered structures having layers containing carbon nanotubes.

A first aspect of the method for manufacturing a layered structure according to the present disclosure includes a first step of applying a first coating liquid to a main surface of a substrate, the first coating liquid having a dispersoid containing carbon nanotubes and a liquid that is a dispersion medium in which the dispersoid is dispersed; a second step of performing a drying process on 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 that contains the dispersoid; a fourth step of applying a second coating liquid to the first layer from the opposite side to the main surface, the second coating liquid containing a precursor of a polymer material; and a fifth step of polymerizing the precursor to form a second layer that contains the polymer material, wherein oxygen radicals are supplied to the liquid in the third step, and the oxygen radicals are generated using oxygen plasma in the third step .
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 to a main surface of a substrate, the first coating liquid having a dispersoid containing carbon nanotubes and a liquid that is a dispersion medium in which the dispersoid is dispersed; 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 that contains the dispersoid; a fourth step of applying a second coating liquid to the first layer from the side opposite the main surface that contains a precursor of a polymer material; and a fifth step of polymerizing the precursor to form a second layer that contains the polymer material, wherein in the third step, reactive plasma is generated on the side of the liquid opposite the main surface.

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 when forming the structure. After the structure is formed, it is easy to separate the substrate from the second layer.

1 is a flowchart illustrating a manufacturing process for an electronic device. FIG. FIG. 2 is a side view showing a state in which a release layer is formed on a substrate. FIG. 2 is a side view showing a state in which a polyimide layer is formed on a release layer. FIG. 2 is a plan view showing a state in which a polyimide layer is formed on a release layer. FIG. 10 is a cross-sectional view showing a state in which a barrier layer is formed on a polyimide layer. FIG. 2 is a plan view showing a state in which a barrier layer is formed on a polyimide layer. FIG. 10 is a cross-sectional view showing a state in which a circuit layer is formed on a barrier layer. 10A to 10C are cross-sectional views illustrating a step of peeling off the laminate from the substrate. 1 is a flowchart illustrating the formation of a release layer. FIG. 10 is a side view schematically showing an aspect in which ultraviolet light is irradiated while the substrate is being moved. FIG. 10 is a side view schematically showing an embodiment in which ultraviolet light is irradiated without moving the substrate. 10 is a flowchart showing another example of forming a release layer. FIG. 2 is a side view schematically showing the generation of reactive plasma.

<1. General Description of the Manufacturing Process of Electronic Devices>
1 is a flow chart illustrating a manufacturing process of an electronic device, such as a display device, and FIG. 2 is a side view of a substrate 10 viewed from a direction perpendicular to its thickness direction.

Step S10 is the process of preparing the 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 the direction perpendicular to the main surface 10a. In Figures 1 to 8, direction P is the direction from the main surface 10a toward the surface 10b in the thickness direction of the substrate 10.

When viewed from a plane along direction P, the shape and size of substrate 10 are not particularly limited. For example, when viewed from a plane, substrate 10 has a rectangular shape. The plan view corresponds to a view from a direction perpendicular to main surface 10a.

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

By using the substrate 10 as a carrier substrate, the flexible polyimide layer 30 is stably held, making it easier to form the circuit layer 50 on this polyimide layer 30. Using the substrate 10 as a carrier substrate makes it easier to manufacture electronic devices using existing manufacturing equipment (e.g., coating equipment, heat treatment equipment) that forms circuit layers on general substrates.

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.

In the slit coating method, for example, a slit coater is used. In a slit coater, for example, a slit nozzle that ejects the first coating liquid 102 as a coating liquid is scanned at a constant speed across the substrate 10, which 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 applied to the substrate 10.

A process for cleaning the principal surface 10a may be performed between steps S10 and S11. Examples of such processes include chemical cleaning, in which the principal surface 10a is cleaned with a chemical solution, brush cleaning, in which contaminants are mechanically removed from the principal surface 10a with a brush, and a process in which the principal surface 10a is irradiated with ultraviolet light to decompose and remove contaminants.

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. The dispersion medium may be either an aqueous liquid or an organic liquid, or both. The liquid to be dispersed may further include a dispersant. An example of a dispersant is a surfactant. The dispersant is not limited to a liquid, but may also be a solid.

Step S12 is a process for drying the first coating liquid 102 (hereinafter simply referred to as "drying process" in the drawings). Examples of this drying process include vacuum drying and heating. This drying process reduces at least a portion of the dispersion medium in the first coating liquid 102.

Step S13 is a process for forming a release layer 20 from the first coating liquid 102 after drying. For example, step S13 is a process for forming a release layer 20 containing dispersoids by removing the dispersed liquid while modifying it. Here, "modification" includes, as one form, decomposition of the dispersed liquid, and various forms are exemplified below.

By removing the dispersion liquid, the release layer 20 is obtained as a paper-like material in which the 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 the 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.

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 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.

In this embodiment, the second coating liquid 103 covers the release layer 20 in plan view and fits within the main surface 10a. 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.

Figure 4 is a side view showing the state in which the second coating liquid 103 has been applied to the release layer 20. Figure 4 shows the outer edge 20f of the release layer 20 in a plan view.

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

The second coating liquid 103 contains a precursor of a polymeric material, which in this embodiment is a polyimide precursor. Step S15 is a process of polymerizing the precursor to form a layer containing a polymeric material, which in this embodiment is a polyimide layer 30. For example, in step S15, the second coating liquid 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.

Figure 5 is a plan view showing the state in which the polyimide layer 30 has been 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 come into contact with the main surface 10a.

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.

If the adhesion between the release layer 20 and the substrate 10 decreases, there is a concern that the release layer 20 will 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 contacts the main surface 10a outside the outer edge 20f of the release layer 20 functions to prevent the release layer 20 from peeling off from the substrate 10 during the manufacturing process of the display device.

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

The barrier layer 40 is a layer that prevents moisture from penetrating into the circuit layer 50 (described below), and is composed of, for example, a silicon nitride (SiNx) film. The barrier layer 40 is formed by various well-known methods, such as CVD.

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

Step S16 is a process of forming a circuit layer 50 on the barrier layer 40. Figure 7 is a plan view showing the circuit layer 50 formed on the barrier layer 40. Figure 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.

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.

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

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

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 easily peels off. Therefore, the polyimide layer 30 is easily peeled off from the substrate 10 while minimizing damage to the polyimide layer 30.

After peeling, the laminate 60 has a structure in which an electronic circuit is formed on a thin polyimide substrate. Such a laminate 60 can be used as a flexible device, such as a main component of a display device.

Due to 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 thickness of 100 nm or less, and is unlikely to interfere with the flexibility of the laminate 60. The release layer 20 may also function as a barrier layer.

Step S17 may be omitted in some cases. For example, when the peripheral area 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.

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.

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. Because an expensive laser annealing device is not required, the polyimide layer 30 can be peeled off from the substrate 10 inexpensively.

In this embodiment, no laser is used to peel the polyimide layer 30, so damage to the polyimide layer 30 when peeling it from the substrate 10 is minimal. This makes it less likely that stress will be generated in the polyimide layer 30, causing deformation such as winding up of the polyimide layer 30, and also reduces mechanical damage to the circuit layer 50 on the polyimide layer 30. Suppressing such deformation and damage contributes to improving the manufacturing yield of devices that use the laminate 60.

The carbon nanotubes contained in the release layer 20 are electrically conductive. This conductivity helps to suppress the generation of static electricity when the polyimide layer 30 is peeled from the substrate 10. Suppressing the generation of static electricity helps to suppress electrical damage to the circuit layer 50.

2. Explanation of the method for producing 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.

Step S11 can be considered the first process of applying a first coating liquid 102 containing a dispersoid containing carbon nanotubes and a liquid to be dispersed in, onto the main surface 10a of the substrate 10.

Step S12 can be considered the second process in which the first coating liquid 102 applied to the main surface 10a is dried.

Step S13 can be considered the third process in which the dispersed liquid is transformed and removed to form a first layer containing dispersoids (release layer 20 in the above example).

Step S14 can be considered the fourth process in which a second coating liquid 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 the main surface 10a.

Step S15 can be considered the fifth step 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).

It is easy to form a structure (circuit layer 50 in the above example) on the side of the second layer opposite the main surface 10a because the substrate 10 serves as a support layer when forming the structure. After the structure is formed, it is easy to separate the substrate 10 from the second layer.

The following mainly describes various methods for steps S12 and S13.

<2-1. Modification 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, heat treatment is performed. After step S13b is performed, the process returns to the flowchart shown in FIG. 1 (specifically, the start of execution of step S14).

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

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 form of the transformation described above. Carbon monoxide and carbon dioxide are removed as gases, and water is removed as a liquid or gas from the first coating liquid 102, leaving a dispersion medium containing carbon nanotubes on the main surface 10a.

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 primarily emit light with a wavelength of 254 nm. Excimer lamps primarily emit light with a wavelength of 172 nm.

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

Modification of the dispersion liquid using oxygen radicals O* makes it easier to avoid high-temperature processing compared to removing the dispersion liquid simply by heating. For example, without using oxygen radicals O*, heating to approximately 500°C is required to remove the dispersion liquid. In contrast, using oxygen radicals O* allows for lower heating temperatures, improving the efficiency of forming the release layer 20.

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

For example, in step S12, a drying process is performed by heating, and then step S13a is performed without heating or with heating maintained. Then, step S13b is performed at a temperature higher than that used in step S12. For example, in steps S12 and S13a, heating at 100 to 150°C is used.

The fact that the heat treatment in step S13b does not exceed 700°C helps prevent deterioration of the characteristics of the carbon nanotubes in the release layer 20.

Two modes are proposed for performing step S13a. Figure 11 is a side view that schematically shows a mode in which ultraviolet light is irradiated while the substrate 10 is moved. Figure 12 is a side view that schematically shows a mode in which ultraviolet light is irradiated without moving the substrate 10.

The excimer lamp 8 comprises multiple lamp tubes 81. Each lamp tube 81 extends along direction M, which is drawn perpendicular to the paper surface. Multiple lamp tubes 81 are arranged side by side along direction Q. Direction Q is not parallel to direction M, and here, direction Q is shown as being perpendicular to direction M.

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

In the embodiment shown in Figure 11, the substrate 10 moves along direction Q. The substrate 10 is transported in direction Q while its surface 10b is supported by, for example, a plurality of rollers 9 extending along direction M. Rotation of the rollers 9 in the clockwise direction in the drawing contributes to the movement of the substrate 10 in direction Q.

The configuration shown in Figure 11 requires a transport mechanism, but requires fewer lamp tubes 81. The configuration shown in Figure 12 does not require a transport mechanism, but requires a larger number of lamp tubes 81.

<2-2. Transformation of the 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 start of step S14).

The temperature of the heat treatment performed in step S13d is, for example, 200°C or higher. The fact that the heat treatment in step S13d does not exceed 700°C helps prevent deterioration of the characteristics of the carbon nanotubes in the release layer 20.

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

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

When oxygen gas is used to generate the reactive plasma, the generated oxygen plasma supplies oxygen radicals O* to the first coating liquid 102. A chemical reaction similar to that caused by the ultraviolet light irradiation described above leaves a dispersion medium containing carbon nanotubes on the main surface 10a.

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 organic matter to produce water as described below. This decomposition is one form of the transformation described above. The water is removed from the first coating fluid 102 as a liquid or gas, and the dispersion medium containing the carbon nanotubes remains on the main surface 10a.

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

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 larger amount of plasma than reactive plasma using oxygen gas.

Figure 14 is a side view showing the generation of reactive plasma. The chamber 7 contains a pair of electrodes 83. A mixed gas 82 is supplied between the pair of electrodes 83. The mixed gas 82 is supplied from outside the chamber 7, and the example shown here shows a configuration in which the mixed gas is supplied between the pair of electrodes 83.

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.

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

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

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

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 processing 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.

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 modified and removed by, for example, heating the first coating liquid 102 at a temperature of 500°C for about 30 minutes. Such heat treatment can reduce the efficiency of forming the release layer 20. However, the modification exemplified in the embodiment requires a lower temperature for the heat treatment, improving the efficiency of forming the release layer 20.

3. Explanation of the manufacturing method of the electronic device
Steps S16, S17, and S18, in combination with steps S11-S15 for fabricating a layered structure, can be considered a method for fabricating an electronic device having electronic circuitry contained in circuit layer 50.

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

Step S17 can be considered a seventh step in which, in a plan view, the first layer, exemplified by the release layer 20, and the second layer, exemplified by the polyimide layer 30, are cut between the outer edge 20f and the predetermined region R. In this case, step S18 can be considered an eighth step in which the substrate 10 is peeled off from the first layer.

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

<Transformation>
Although the embodiments of the present disclosure have been described above, various modifications 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.

The technology described above can be used to manufacture display devices such as organic electroluminescence (EL) displays and liquid crystal displays, for example, flexible devices with circuits formed on polyimide substrates.

10 Substrate 10a Main surface 20 Release 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 Direction (perpendicular to the main surface) R Predetermined region S11 Step (first process)
S12 Step (Second Process)
S13 Step (Third Process)
S14 step (fourth process)
S15 step (fifth process)
S16 step (sixth process)
S17 step (7th process)
S18 step (8th step; 7th step)

Claims (7)

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;
and a fifth step of polymerizing the precursor to form a second layer comprising the polymeric material ;
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 . 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, reactive plasma is generated on the side of the liquid opposite to the main surface . 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. 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. 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. 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. 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.