Printing method and manufacturing method of electronic device

Abstract

Provided is a printing method which involves: a member preparation step for preparing a porous member, the porous section of which is filled with ink; a target preparation step for preparing a printing target which has a pattern region formed on the surface thereof; and an adhesion step for causing the ink filling the porous section to adhere to the pattern region by scanning the porous member across the surface of the printing target.

Description

[Technical Field]

[0001] The present invention relates to a printing method, a method for manufacturing an electronic device, and a porous member. [Background technology]

[0002] Conventionally, techniques have been proposed for forming metal wiring for electronic components by applying a metal nanoparticle ink onto a substrate. For example, Patent Document 1 describes a technique for forming a metal layer by irradiating the surface of a polymer layer formed on a substrate with ultraviolet light to form a reactive surface, and then applying a metal nanoparticle ink to the reactive surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-44373 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 is a technology for applying ink to a flat surface using a blade, and does not take into consideration the application of ink to objects that are not flat, such as curved surfaces. Furthermore, the technology described in Patent Document 1 is significantly limited in the types of substrate surfaces and inks that can be used, leaving problems in terms of versatility.

[0005] The present invention has been made in view of these circumstances, and one of its exemplary purposes is to provide a printing method that enables a desired print pattern to be easily produced, a method for manufacturing an electronic device, and a porous member. [Means for solving the problem]

[0006] In order to solve the above problem, a printing method of one embodiment of the present invention includes a member preparation step of preparing a porous member having pores filled with ink, an object preparation step of preparing a printing object having a pattern area formed on its surface, and an attachment step of adhering the ink filled in the pores to the pattern area by sweeping the porous member over the surface of the printing object.

[0007] Another aspect of the present invention is a method for manufacturing an electronic device using the above printing method.

[0008] Another aspect of the present invention is a porous member comprising a porous body having pores and a molecular modification film formed so as to cover the inner surfaces of the pores, the pores having a plurality of openings and constituting voids of the porous body.

[0009] Any combination of the above components and any transformation of the present invention into a method, device, system, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0010] According to the present invention, it is possible to easily create a desired print pattern. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a schematic configuration of a printing member according to an embodiment of the present invention; [Figure 2] 1 is a flowchart illustrating the flow of a printing method according to an embodiment of the present invention. [Figure 3] 10A to 10C are diagrams illustrating an example of a film forming step according to the embodiment. [Figure 4] FIG. 1 is a diagram for explaining the contact angle of a water droplet. [Figure 5] FIG. 5(a) is a side view of a printing object according to one embodiment of the present invention, and FIG. 5(b) is a top view of a printing object according to one embodiment of the present invention. [Figure 6]FIG. 6(a) is a diagram showing the state when the sweeping of the printing member starts, and FIG. 6(b) is a diagram showing the state after the sweeping of the printing member. [Figure 7] FIG. 2 is a top view of an example of a print target after printing by the printing method according to the embodiment. [Figure 8] FIG. 10 is a diagram showing the printed result of electrode wiring according to Example 1. [Figure 9] FIG. 10 is a photograph showing the appearance of the surface of the printing object after printing in Example 2, observed with an optical microscope. [Figure 10] FIG. 10 is a photograph showing the appearance of a print object after printing in Example 3. [Figure 11] FIG. 10 is a diagram showing a printed result of wiring according to Example 4. [Figure 12] FIG. 10 is a diagram showing the printing result of an organic semiconductor according to Example 5. [Figure 13] FIG. 13(a) is a diagram showing the surface of a printing object on which a pattern area according to Example 6 has been formed, and FIG. 13(b) is a diagram showing the surface of the printing object after printing according to Example 6. [Figure 14] FIG. 13 is a diagram showing a print result according to Example 7. [Figure 15] FIG. 15 is a photograph of the surface of the printing object after printing in Example 8, observed with an optical microscope. DETAILED DESCRIPTION OF THE INVENTION

[0012] [background] Toward a future society in which humans and computers are more comfortably connected, there is a strong demand for various information input / output devices that are lighter, more flexible, and more free-form. However, current processes such as photolithography lack the means to form wiring and electronic circuits on complex three-dimensional shapes, such as free-form curved surfaces. Furthermore, significant limitations exist not only in terms of shape but also in terms of resolution, such as the width of the wiring (also simply referred to as "line width"). These are challenges facing the realization of free-form devices. A free-form shape here refers to a shape that cannot be realized by bending or folding a flat surface, such as the shape of a computer mouse.

[0013] Furthermore, with the development of printed electronics, a method has been developed in which wiring patterns are formed by forming patterns with different surface free energies on the surface of a substrate and then applying ink (the Supernap (registered trademark) method, hydrophilic-hydrophobic patterning method). However, the above-mentioned problems have not yet been resolved, and there is a need to develop a "method and printing method for applying ink evenly to curved surfaces."

[0014] [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted as appropriate. Furthermore, the configurations described below are examples and do not limit the scope of the present invention in any way.

[0015] FIG. 1 is a diagram showing a schematic configuration of a printing member 10 according to one embodiment of the present invention. The printing member 10 according to this embodiment is a member used for printing on various printing objects. As shown in FIG. 1, the printing member 10 includes a porous member 100 and a supply member 140, and the porous member 100 and the supply member 140 are bonded to each other by an adhesive layer 120.

[0016] The porous member 100 is a member having holes, and has a surface on which the openings of the holes are formed (hereinafter also referred to as the "opening surface"). For example, a plurality of openings may be formed on the bottom surface (opening surface 102) and the side surface 104 of the porous member 100.

[0017] In this embodiment, the pores are filled with various known inks. The ink may be filled into the pores by, for example, soaking in through the openings. The ink may include a conductive material, an organic semiconductor, or a ferroelectric. When a conductive pattern is to be produced, the ink may include various conductive materials. In this case, for example, the ink may be a dispersion of metal nanoparticles such as silver nanoparticles in a solvent, or may include various metals such as gold, copper, and nickel, or may include a conductive polymer. When an organic thin film pattern is to be produced, the ink may include various organic materials, such as organic semiconductors. Furthermore, various materials can be used as long as they can be made into ink, and in addition to the above inks, insulating inks and the like can also be used.

[0018] The solvent may be a highly polar or a low-polarity solvent. The solvent may be any of various organic solvents, such as hydrocarbon solvents such as octane and hexane, aromatic hydrocarbon solvents such as xylene and toluene, or halogenated solvents such as chlorobenzene and chloroform. The solvent may also be a water- and alcohol-based solvent used in water-soluble inks. Furthermore, the solvent may be a mixture of these solvents, and the prepared ink may contain additives such as a thickener and a surfactant.

[0019] The pore diameter of the pores is not particularly limited, but is preferably in the range of 50 nm to 3 mm. When the pore diameter is 50 nm or more, the pores can be easily filled with ink. Furthermore, when the pore diameter is 3 mm or less, the pores can retain ink well and ink leakage is suppressed. The pore diameter of the pores is more preferably in the range of 1 μm to 1000 μm, and even more preferably in the range of 10 μm to 200 μm. Note that the larger the pore diameter of the pores, the more uneven and rough the surface of the porous member 100 becomes, and this disruption of flatness may cause defects such as scratches on the printed object.

[0020] The porous member 100 according to this embodiment has a porous body with a plurality of pores. The pores have a plurality of openings and constitute the porous portion of the porous member 100. The size of the pores is not particularly limited, but the pores may be micropores with a pore diameter of less than 2 nm, mesopores with a pore diameter in the range of 2 to 50 nm, or macropores with a pore diameter of more than 50 nm. However, depending on the size of the molecules contained in the ink, penetration through micropores and mesopores may be difficult. Therefore, it is preferable that the pores be macropores.

[0021] The material of the porous body is not particularly limited, but may be, for example, an inorganic material or an organic material. The porous body is preferably elastic and flexible. This prevents the porous body from damaging the object to be printed during printing. Furthermore, when the surface of the object to be printed has a three-dimensional shape, such as a curved surface, a flexible porous body allows the porous body to deform along the surface of the object to be printed, making it easier to align the opening surface with the object to be printed, making printing easier. Examples of highly flexible substances include porous bodies formed from various organic polymer materials, and specifically, polyolefin-based or polyurethane-based polymer materials.

[0022] The porous body may be made of a fibrous material such as cloth or nonwoven fabric, and may be a sponge made of carbohydrates such as cellulose. When the porous body is made of a fibrous material, the gaps between the fibers form pores. The size of the air bubbles contained in the sponge may be, for example, an average diameter of 1500 to 3000 μm.

[0023] When an organic solvent is used as the solvent, it is preferable that the porous body is poorly soluble in the organic solvent. For example, it is preferable that the porous body is made of a polyolefin-based polymer material. Felts and sheets whose fibers are made of fluorine-based organic molecules have excellent solvent resistance and can be effectively used as porous bodies.

[0024] The porous member 100 according to this embodiment has a molecular modification film formed to cover the inner surfaces of the pores. The molecular modification film according to this embodiment is formed to cover the inner surfaces of the pores of the porous body, and may be, for example, an organic thin film such as a self-assembled monolayer (SAM). By forming a molecular modification film such as a SAM film in the pores, ink can be more easily adhered to the printing target and the porous body can be prevented from dissolving in the ink.

[0025] The supply member 140 is configured so that ink can be supplied to the pores of the porous member 100 as needed. For example, holes or meshes that communicate with the pores may be formed in the supply member 140 and the adhesive layer 120, and ink may be supplied to the pores from the supply member 140 through these holes or meshes. The supply member 140 may also be configured so that ink can be supplied to the pores from the supply member 140 as the ink filled in the pores decreases due to printing.

[0026] In this embodiment, an example is described in which ink is supplied using a supply member 140 adhered to the porous member 100 by an adhesive layer 120, but the method of supplying ink to the porous member 100 is not limited to this. For example, ink may be supplied to the porous member using a dispenser such as a syringe. In this case, it is also possible to directly pierce the porous member 100 with a syringe needle, integrate the porous member 100 and the dispenser, and use the dispenser to supply ink to the porous member while printing. In this case, the dispenser may be fixed directly to the porous member 100 without an adhesive layer or the like.

[0027] [Printing method] Fig. 2 is a flowchart illustrating the flow of a printing method according to one embodiment of the present invention. As shown in Fig. 2, the printing method according to this embodiment includes a member preparation step (S1), a target object preparation step (S2), and an attachment step (S3). Note that the steps in the printing method do not have to be performed in the order shown in Fig. 2. For example, the target object preparation step may be performed before the member preparation step, or the target object preparation step and the member preparation step may be performed in parallel.

[0028] The member preparation step is a step of preparing a porous member whose pores are filled with ink. For example, in the member preparation step, the pores of the porous member may be filled with ink to prepare a porous member whose pores are filled with ink. The amount of ink filled is preferably sufficient to approximately saturate the ink. The filling method may be various methods, such as dipping the porous member into an ink container or dispensing.

[0029] In the component preparation process, various surface treatments may be performed on the pores before filling them with ink. For example, the component preparation process may include a film formation process in which a molecularly modified film is formed to cover the inner surfaces of the pores. Examples of processes for forming a molecularly modified film include silane coupling treatments, such as alkoxysilanes, chlorosilanes, and alkylchlorosilanes. These silane coupling agents may contain amino groups and epoxy groups. Silane coupling treatments include liquid-phase and gas-phase treatments. Gas-phase treatments are preferred because they can be used to treat large areas and large volumes with a small amount of silane coupling agent, and are therefore highly productive and versatile. By performing such surface treatments on a porous material, a porous component can be prepared, with a molecularly modified film formed to cover the inner surfaces of the pores.

[0030] FIG. 3 is a diagram illustrating an example of a film formation process according to this embodiment. As shown in FIG. 3, in the film formation process according to this embodiment, a porous body 110 and a liquid film material 24 are placed inside a container 20, and the container 20 is sealed with a lid 22. A UV (Ultraviolet) ozone cleaner may be used to pretreat the porous body, shielding it from direct UV light irradiation. The ozone generated within the cleaner oxidizes the porous surface and interior, pretreating the porous body to make it more susceptible to reaction with a silane coupling agent. Here, an example is described in which the porous body 110 is made of a polyolefin-based organic material, and the film material 24 is FAS (1H,1H,2H,2H-Perfluorodecyltriethoxysilane), a fluorine-based material represented by the following chemical formula: [ka]

[0031] The film material 24 is heated, for example, at 65 to 120°C, and the gasified film material 24 is deposited inside the pores of the porous body 110, thereby forming a molecularly modified film that covers the inner surfaces of the pores. The treated porous body 110 may have unreacted silane coupling agent residue on its surface. Therefore, the treated porous body 110 may be immersed in IPA (isopropyl alcohol) for 20 minutes, for example, to clean it, and then dried in a vacuum oven. Forming a molecularly modified film on the inner surfaces of the pores in this manner improves the water repellency of the pores. The film formation process according to this embodiment uses a gas-phase treatment, which allows molecules to penetrate deep into the pores of the porous body 110, thereby more reliably molecularly modifying the pore surfaces.

[0032] An example of the results of a water-repellent treatment will be described with reference to FIG. 4. FIG. 4 shows a component 112 to be measured for water repellency and a water droplet 26 dropped on its surface. The inventors confirmed that by performing a surface treatment using FAS (heating temperature: 65°C, heating time: 24 hours) on a polyolefin-based organic material to form a molecularly modified film, the water contact angle θ increased from 110° to 130°, improving the water repellency of the organic material. Furthermore, when observing the change in the contact angle over time, it was confirmed that without molecular modification, the water contact angle changed from 110° to 108° 5 minutes after the water droplet 26 was dropped. On the other hand, with molecular modification, it was confirmed that the water contact angle remained at 130° 5 minutes after the water droplet 26 was dropped. This change in the contact angle over time indicates the ease with which the pores of the porous component absorb liquid, indicating that the material was molecularly modified with FAS.

[0033] The film material 24 is not limited to FAS, but may be, for example, APTES ((3-Aminopropyl)triethoxysilane) represented by the following chemical formula. [ka]

[0034] In this case, the porous body 110 and membrane material 24 are arranged as shown in Figure 3, and the membrane material 24 is heated, for example, at a temperature of 65°C for 24 hours. The gasified membrane material 24 is then deposited inside the pores of the porous body 110, forming a molecularly modified membrane that covers the inner surfaces of the pores. The inventors have confirmed that this type of surface treatment results in a contact angle (water) of 125°, improving water repellency. The cleaning and drying methods after treatment are the same as those used when using the FAS described above.

[0035] The object preparation step is a step of preparing a printing object having a pattern area formed on its surface. In the object preparation step, the printing object may be prepared by forming a pattern area having a desired shape on the surface of the substrate of the printing object. The pattern area according to this embodiment is configured to be more likely to adhere to or retain ink than other areas on the surface of the printing object.

[0036] Specifically, in the object preparation step, a pattern region having a different surface free energy from other regions may be formed on the surface of the substrate of the printing object. For example, a substrate having a surface made of a polymer material may be prepared, the surface of the substrate may be covered with a mask having a desired pattern, and ultraviolet light may be irradiated onto the surface of the substrate through the mask. The ultraviolet light may be, for example, vacuum ultraviolet light having a wavelength of 200 nm or less (ultraviolet light having a wavelength of 172 to 250 nm), specifically, vacuum ultraviolet light of 172 nm produced by xenon excimer. By irradiating the substrate with ultraviolet light, the surface of the substrate is modified to allow metal nanoparticles to be fused thereto, forming a pattern region. In addition to the above-mentioned ultraviolet light treatment method, various plasma treatments may also be used.

[0037] In addition, in the object preparation step, a pattern region may be realized by forming a hydrophilic surface and a hydrophobic surface on the surface of the printing object. In this case, the pattern region may be composed of a hydrophilic surface. By adjusting the surface wettability between hydrophilic and hydrophobic in this way, printing with aqueous ink becomes possible, and aqueous ink can be adhered to and retained in the pattern region.

[0038] The pattern region is not limited to one formed by differentiating the surface free energy from the surrounding area, but may be formed by providing a region with a different three-dimensional structure, such as a step or a groove (bank). Alternatively, the pattern region may be formed as a region with both a different surface free energy and a different three-dimensional structure from the surrounding area. Regions with different three-dimensional structures can be formed using, for example, photolithography, and various methods such as etching using light and chemicals are possible. Another method for forming the pattern region is heat pressing using a mold. The grooves are configured to hold ink more easily than other areas, and the pattern is formed by utilizing capillary action, which causes the liquid to spread along the steps and grooves. The depth of the grooves may be, for example, 10 nm to 10 μm.

[0039] The surface of the printing object on which the pattern area is formed may have various shapes, for example, may be flat, may be curved, may be other three-dimensional shapes, free-form shapes, etc. In this embodiment, an example will be described in which the surface of the printing object on which the pattern area is formed is configured as a curved surface.

[0040] An example of the configuration of a printing object according to this embodiment will be described with reference to Figures 5(a) and (b). Figure 5(a) is a side view of a printing object 30 according to one embodiment of the present invention, and Figure 5(b) is a top view of a printing object 30 according to one embodiment of the present invention.

[0041] As shown in Figures 5(a) and 5(b), the printing target 30 according to this embodiment has a flat portion 300 and a curved portion 302. As shown in Figure 5(b), a pattern region 304 (a region indicated by dotted hatching) is formed in the curved portion 302. Note that the shape of the pattern region 304 is not limited to the rectangular shape shown in Figure 5(b), and may include various shapes such as a linear shape, a circular shape, an elliptical shape, or a polygonal shape.

[0042] 6(a) and 6(b) are diagrams illustrating the adhesion process according to this embodiment, where Fig. 6(a) shows the state when the sweeping of the printing member 10 starts, and Fig. 6(b) shows the state after the sweeping of the printing member 10.

[0043] The adhering step is a step of sweeping the porous member 100 over the surface of the printing object 30, thereby adhering the ink filled in the pores of the porous member 100 to the pattern area. In the adhering step according to this embodiment, the printing member 10 is swept along the surface while pressing the open surface 102 of the porous member 100 of the printing member 10 against the surface of the curved portion 302 of the printing object 30. This causes the ink filled in the pores of the porous member 100 to adhere to the pattern area on the surface of the curved portion 302.

[0044] At this time, ink can be applied to the pattern area by utilizing the balance between the capillary phenomenon (moisture absorption) generated by the pores of the porous member 100 and the capillary phenomenon (coating liquid, coating) between the porous member 100 and the surface (curved surface portion 302) of the printing object 30. According to the printing method of this embodiment, by utilizing (or adjusting) the balance between the magnitudes of the two capillary phenomena, it becomes possible to more easily create the desired print pattern. Naturally, areas where a print pattern is not required must have a surface state that repels ink.

[0045] The sweep speed of the printing member 10 is not particularly limited, but may be adjusted depending on the surface tension of the ink, the drying speed of the solvent contained in the ink, and the resolution of the printed pattern. If the sweep speed is too fast, adjacent patterns will not separate, resulting in poor printing. If the sweep speed is too slow, solids may precipitate, causing defects such as scratches on the printed object. For example, the sweep speed may be 0.1 to 500 mm / s, preferably 1 mm / s or higher, and even more practical if it is 5 mm / s or higher.

[0046] It is preferable to sweep the printing member 10 while pressing it against the surface of the printing object 30. For example, sweeping may be performed while pressing the printing member 10 against the printing object 30 with a load approximately equal to the printing member 10's own weight. In this embodiment, the ink fills the pores of the porous member 100 to a saturated state (or a state close to saturation). Therefore, during sweeping, a small amount of ink has seeped out onto the surface of the porous member 100. Therefore, when the printing member 10 is pressed against the printing object 30, ink is always present between the porous member 100 and the printing object 30, and the porous member 100 (more specifically, the opening surface 102) is not in direct contact with the printing object 30.

[0047] In the adhesion step according to this embodiment, a pattern with a thickness of about 10 to 2000 nm can be formed on the surface of the printing object. If a greater thickness is required, the print pattern can be made thicker by repeating the adhesion step, such as by applying multiple coats.

[0048] 7 is a top view of an example of the printing object 32 after printing by the printing method according to this embodiment. As shown in Fig. 7, ink is applied to an area 306 (hatched area) corresponding to the pattern area 304 in Fig. 5(b), and a print pattern is printed on the printing object 32.

[0049] As described above, the printing method according to this embodiment can print a print pattern on a curved surface, and can uniformly deposit ink on a three-dimensional or free-form shape, achieving high-precision printing. Furthermore, by using the printing method according to this embodiment to form various wiring patterns, for example, a method for manufacturing electronic devices can be provided. Therefore, the printing method according to this embodiment makes it possible to manufacture electronic devices with complex shapes (e.g., curved free-form shapes) that cannot be realized using current processes. Furthermore, the printing method according to this embodiment can be applied to inks containing various materials, not just metals, such as organic semiconductors, and therefore provides a highly versatile method for manufacturing electronic devices.

[0050] The method for manufacturing an electronic device according to this embodiment can be employed as a method for manufacturing various products, such as products used in the automotive, medical, IoT (Internet of Things), and robotics fields. Specifically, the method for manufacturing an electronic device according to one embodiment of the present invention can be applied to a wide range of applications, including various display elements, sensors, and electronic circuits. The printing method according to this embodiment can be a highly useful technique industrially as a printing technology for objects with three-dimensional structures.

[0051] Conventional techniques for printing wiring on curved surfaces include the methods described in the following references. (References) [1] Y. Yoshida, H. Wada, K. Izumi, and S. Tokito, “Highly conductive metal interconnects on three dimensional objects fabricated with omnidirectional ink jet printing technology”, JJAP. 56, 05EA01 (2017). [2] K. Izumi, Y. Yoshida, and S. Tokito, “Novel soft blanket gravure printing technology with an improved ink transfer process”, Flex. Print. Electron. 2, 024003 (2017). [3] K. Izumi, Y. Yoshida, and S. Tokito, “Soft blanket gravure printing technology for finely patterned conductive layers on three-dimensional or curved surfaces”, JJAP. 56, 05EA03 (2017). [4] K. Nomura, Y. Kusaka, H. Ushijima, K. Nagase, and H. Ikedo, “Screen-pad printing for electrode patterning on curvy surfaces”, Microsyst Technol. 22, 635-638 (2016).

[0052] Conventional printing technologies are limited to limited shapes, and the resolution of printed objects (such as wiring) is poor, making it impossible to form wiring with a line width of 30 μm or less. Furthermore, photolithography has few applications to curved surfaces, and is unable to adapt to objects with steps of, for example, 1.5 cm or more in height, because it is unable to follow the height. The printing method of this embodiment enables high-resolution printing with a line width of 10 μm or less, which is advantageous not only for free-form device fabrication but also for miniaturizing devices.

[0053] Furthermore, the printing method according to this embodiment can lead to the creation of new applications, such as not only turning the fingertips of robotic hands into sensors, but also manufacturing sensors that completely cover the fingertips. For example, by combining these sensors with myoelectric elements, new prosthetic limbs and robotic hands can be proposed as service robots using AI (artificial intelligence). In recent years, attempts have been made to directly bond prosthetic limbs to curved bones, and the printing method according to this embodiment could be useful. Furthermore, because it is possible to construct not only electrode layers but also organic semiconductor layers, the printing method according to this embodiment can be applied to a variety of electronic circuit manufacturing technologies.

[0054] Furthermore, the printing method according to this embodiment allows the entire process to be carried out at a relatively low temperature. For example, the printing method according to this embodiment allows the entire process to be carried out at a temperature of 100°C or less, and by carefully selecting the components, the entire process can be carried out at a temperature of 60°C or less.

[0055] [Example] The present invention will be explained in more detail below using examples, but the following descriptions of printing members, printing objects, inks, etc. do not limit the embodiments of the present invention in any way.

[0056] Example 1 In Example 1, a substrate was prepared that was made of a polycarbonate (PC) film with Cytop (registered trademark) formed on the surface, which had a curved portion in the center, like the printing object 30 described with reference to Figure 5. The printing object was prepared by irradiating the surface of the substrate with ultraviolet light having a wavelength of 172 nm through a mask to form a pattern area.

[0057] In Example 1, a porous body made of a polyolefin-based organic material (MAPS, manufactured by Inoac Corporation) was prepared. Here, porous body A (thickness: 2.25 mm, cell diameter: 50 μm, porosity: 85%, density: 0.139 g / cm) was used. 3 , tensile strength 229 KPa, elongation: 220%, hardness: 8 (Asker C)), porous body B (thickness: 1.85 mm, cell diameter: 90 μm, porosity: 80%, density: 0.170 g / cm 3 , tensile strength 450 KPa, elongation: 170%, hardness: 11 (Asker C)), porous body C (thickness: 1.50 mm, cell diameter: 200 μm, porosity: 80%, density: 0.2 g / cm 3 The porous bodies were prepared in the following order: porous body A, tensile strength 670 KPa, elongation 150%, hardness 35 (Asker C). When the flexibility of these porous bodies was checked, porous bodies A were softest, followed by porous body B and C, and when the moisture absorption was checked, porous bodies A, B and C had the highest moisture absorption. In Example 1, porous body A was used.

[0058] This porous material was surface-treated using FAS (heating temperature: 65°C, heating time: 24 hours), forming a molecular modification film in the pores of the porous material to obtain a porous component. This porous component was then impregnated with an ink containing silver nanoparticles dispersed in an organic solvent (a mixture of octane, butanol, and methanol). The porous component was then bonded to a supply component to form a printing component. Printing was then performed by pressing the open surface of the porous component against the surface of the print target and sweeping the printing component to deposit the ink onto the patterned area of ​​the print target. Additional ink was added to the porous component as needed. To achieve good printing results, the porous component must be saturated or nearly saturated with ink during printing; therefore, a dispenser or other ink supply system is useful.

[0059] Fig. 8 is a diagram showing the printing result of electrode wiring according to Example 1. As shown in Fig. 8, the printing target 34 according to Example 1 has a flat portion 340 and a curved portion 342, and electrode wiring is printed on the surface of the curved portion 342. In this way, it was confirmed that the printing method according to one embodiment of the present invention makes it possible to print electrode wiring on a curved surface.

[0060] Example 2 In Example 2, a substrate made of a polycarbonate film with curved Cytop formed on its surface was prepared, similar to Example 1. The surface of the substrate was irradiated with ultraviolet light with a wavelength of 172 nm through a mask to form multiple 1 mm square pattern areas, thereby preparing a printing object.

[0061] In Example 2, an ink with a concentration of 0.6 wt % was prepared by dissolving the organic semiconductor P3HT (poly(3-hexylthiophene-2,5-diyl)) in o-xylene. In Example 2, a porous member was prepared in the same manner as in Example 1, except that the porous body was not subjected to a surface treatment. The porous member was then filled with the prepared ink to prepare a printing member. An array of printing patterns was formed by sweeping this printing member over the surface of the printing target.

[0062] In Example 2, the porous body was not subjected to a surface treatment such as SAMs, so there was concern that o-xylene would dissolve the polyolefin-based organic material that constituted the porous body. However, when this example was carried out, no particular abnormalities were observed in the porous body. However, if the porous body is to be used repeatedly, it is considered preferable to perform a surface treatment such as SAMs.

[0063] Fig. 9 is a photograph of the surface 350 of the printing object after printing in Example 2, observed with an optical microscope. As shown in Fig. 9, it can be seen that an array of 1 mm square printing patterns 352 has been formed on the surface 350 of the printing object.

[0064] Example 3 In Example 3, a printing object and a printing member were prepared in the same manner as in Example 2, except for the ink. In Example 3, a flexible ferroelectric ([MDABCO][PF6]) described in the following reference was dissolved in a mixed solvent of water and isopropyl alcohol to prepare an ink with a concentration of 5 wt%. A printing member was prepared by filling a porous body with this ink, and printing was performed using this printing member.

[0065] (References) [5] J. Harada, M. Takehisa, Y. Kawamura, H. Takahashi, and Y. Takahashi, “Plastic / Ferroelectric Crystals with Distorted Molecular Arrangement: Ferroelectricity in Bulk Polycrystalline Films through Lattice Reorientation”, Adv. Electron. Mater. 8, 2101415 (2022).

[0066] Fig. 10 is a photograph showing the appearance of a printing object 354 after printing in Example 3. As shown in Fig. 10, an array of 1 mm square printing patterns 358 can be formed on a curved surface 356 of the printing object 354. Furthermore, according to this example, the ink can be prepared using a solvent containing water and alcohol, and the compound that serves as the ink solute does not contain rare metals, making it possible to print under conditions with a low environmental impact.

[0067] Example 4 In Example 4, a flat substrate was prepared by attaching a PC film to a glass plate and forming a Cytop film on the PC film. The surface of this flat substrate was irradiated with 172 nm deep ultraviolet light through a mask to form a linear pattern area, preparing a printing object. Next, a printing member was prepared in the same manner as in Example 1, and wiring was printed on the printing object by sweeping the printing member while pressing the open surface of the porous member of the printing member against the surface of the printing object.

[0068] Fig. 11 is a diagram showing the printed results of wiring according to Example 4. As shown in Fig. 11, wirings 362, 364, 366, 368, 370, and 372 having a line width of 1 µm to 50 µm could be printed on the surface of the printing object 360. As shown in Fig. 11, in Example 4, fine wiring could be realized with high precision.

[0069] When the resistivity of these wirings was measured, the resistivity of the wiring with a line width of 7.5 μm was 4.09 × 10 -5 Ω·cm, the resistivity of a 10 μm line is 3.62 × 10 -5 Ω·cm, the resistivity of a 20 μm line is 1.95×10 -5 Ω·cm, the resistivity of a 50 μm line is 1.00×10 -5 Ω·cm. Thus, in Example 4, wiring with good electrical conductivity was achieved even when the line width was 10 μm or less. The thickness of these wirings was 50 nm in all cases.

[0070] Example 5 In Example 5, a flat substrate consisting of a glass plate with a PC film attached and a Cytop film formed on the PC film was irradiated with 172 nm deep ultraviolet light through a mask to form multiple rectangular pattern areas, preparing a printing object. Next, a printing member was prepared in the same manner as in Example 1, except that the ink was changed to an ink containing P3HT, and multiple rectangular organic semiconductors (organic semiconductor arrays) were printed by sweeping the printing member.

[0071] FIG. 12 is a diagram showing the printing results of an organic semiconductor array according to Example 5. As shown in FIG. 12, in Example 5, multiple rectangular printing patterns were formed on the surface of the printing object 380. As shown in FIG. 12, a high-resolution printing pattern was formed, which is a resolution equivalent to a 200-300 ppi TFT (Thin Film Transistor) array. In the printing pattern shown in FIG. 12, the horizontal length was 21.4-21.9 μm, and the vertical length was 34.0-35.2 μm.

[0072] Example 6 In Example 6, an epoxy resin-based photoresist (SU-8 3000, manufactured by Nippon Kayaku Co., Ltd.) was used as the substrate for the printing object. First, a film was formed by spin coating under the conditions of Slope / 2 seconds → 500 rpm / 5 seconds → 3000 rpm / 60 seconds, and the film was heated at 95°C for 2 minutes using a hot plate. Then, a 200 mJ / cm 2 The film was irradiated with ultraviolet light having a wavelength of 365 nm and an intensity of 1000 nm. As a result, grooves having a width of about 30 μm were formed in the film.

[0073] Next, in the PEB (post-exposure bake) step, the film was heated at 65°C for 1 minute and then 95°C for 2 minutes. Two PGEMA (propylene glycol monomethyl ether acetate PEG-1) baths were prepared. The film was immersed in the first bath for 30 seconds and then in the second bath for 30 seconds, for a total of 1 minute. The film was then immersed in an IPA (isopropyl alcohol) bath for 1 minute, rinsed with IPA, and spin-dried at 2000 rpm for 40 seconds. The film was then hard-baked at 150°C for 30 minutes to dry. Because the film is a material that easily wets, a water-repellent treatment was applied to adjust its wettability. This resulted in a water droplet contact angle of 75° to 101°, improving water repellency. This water-repellent treated film was used as the printing target.

[0074] Fig. 13(a) is a diagram showing the surface of a printing object 400 on which a pattern region according to Example 6 has been formed. As shown in Fig. 13(a), a printing object 400 was produced in which rectangular grooves 402 measuring 25 µm in the vertical direction, 40 µm in the horizontal direction, and 6 µm in depth were formed on the surface. Next, a printing member prepared in the same manner as in Example 1 was swept over the surface of the printing object 400, and printing was performed.

[0075] Fig. 13(b) is a diagram showing the surface of the printing object 400 after printing in Example 6. As shown in Fig. 13(b), it was confirmed that ink had filled many of the grooves 412 formed on the surface, and printing had been successful. In this way, it was confirmed that by using the printing method according to one embodiment of the present invention, printing can be achieved by filling the ink into the grooves formed on the surface of the printing object, without forming regions with different surface free energies.

[0076] Example 7 In Example 7, a printing object was prepared in the same manner as in Example 6, except that the grooves were linear with a depth of 6 μm and a width of 60 μm, and printing was performed on the surface.

[0077] Fig. 14 is a diagram showing a printing result according to Example 7. As shown in Fig. 14, grooves 422 are formed on the surface of a printing object 420, and it can be seen that ink 424 has entered some of the grooves.

[0078] Example 8 In Example 8, instead of the photoresist (SU-8) used in Examples 6 and 7, a printing object was prepared using polydimethylsiloxane (PDMS) (SIM260, manufactured by Shin-Etsu Chemical Co., Ltd.). Specifically, a mold with a 6 μm-high convex pattern was subjected to a release treatment, and an elastomer mixture of PDMS and a curing agent was poured into the mold. The mixture was baked at 150°C for 30 minutes to harden the silicone elastomer, which was then peeled off from the mold. This resulted in a molded image of the mold, yielding a flat printing object made of PDMS with grooves (concave patterns).

[0079] In Example 8, a printing member was prepared in the same manner as in Example 1, except for the ink. In Example 8, the above-mentioned [MDABCO][PF6] was dissolved in a mixed solvent of an aromatic solvent, alcohol, and water to prepare an ink with a concentration of 2.5 wt %. This ink was filled into a porous body to prepare a printing member, and printing was performed.

[0080] Fig. 15 is a photograph of the surface 440 of the printing object after printing in Example 8, observed with an optical microscope. As shown in Fig. 15, it can be seen that ink 442 is contained in the grooves formed on the surface 440. Although there are also grooves 444 that do not contain ink, it is believed that printing accuracy can be improved by optimizing conditions such as the coating speed, the surface tension of the ink, the height difference of the grooves, and the implementation environment.

[0081] [supplement] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the components and treatment processes, and that such modifications are also within the scope of the present invention. [Industrial Applicability]

[0082] The present invention can be used in a printing method, a method for manufacturing an electronic device, and a porous member. [Explanation of symbols]

[0083] 10 printing member, 30, 32, 34 printing object, 50 line width, 100 porous member, 102 open surface, 110 porous body, 120 adhesive layer, 140 supply member, 300, 340 flat portion, 302, 342, 356 curved portion, 304 pattern area, 352, 358 printing pattern, 360, 354, 380, 400 printing object, 362, 364, 366, 368, 370, 372 wiring, 424, 442 ink, 402, 412, 422, 444 groove

Claims

1. a member preparation step of preparing a porous member having holes filled with ink; an object preparation step of preparing a printing object having a pattern area formed on its surface; an application step of applying the ink filled in the pore portions to the pattern area by sweeping the pore member over the surface of the printing object, The member preparation step includes a film formation step of forming a molecular modification film on the inner surface of the pore portion of the porous member. Printing method.

2. the porous member has a porous body, The film forming step includes a vapor phase treatment for forming a molecular modified film on the inner surfaces of the pores of the porous body. The printing method according to claim 1 .

3. the ink contains metal nanoparticles; The pattern region includes a surface-modified region that is formed by irradiating a polymer material with ultraviolet light and that fuses with the metal nanoparticles. The printing method according to claim 1 or 2.

4. the ink comprises a conductive material, an organic semiconductor, or a ferroelectric material; The printing method according to claim 1 or 2.

5. The pore diameter of the pores is 50 nm to 3 mm. The printing method according to claim 1 or 2.

6. The pattern area is composed of grooves. The printing method according to claim 1 or 2.

7. The surface of the printing object is composed of a curved surface. The printing method according to claim 1 or 2.

8. A method for manufacturing an electronic device using the printing method according to claim 1 or 2.

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