Method for manufacturing base material including conductive pattern, method for manufacturing electronic device, method for manufacturing electromagnetic wave shield film, method for manufacturing planar heating element, and base material including conductive pattern

Abstract

To form a fine circuit pattern and / or form a highly precise circuit pattern, in formation of a conductive pattern using a conductive composition containing conductive particles.SOLUTION: A method for manufacturing a base material including a conductive pattern includes: a filling step of filling a recess provided on the surface of a base material with a conductive composition containing conductive particles, and obtaining a filling pattern; and a pressing step of applying at least pressure to the filling pattern to obtain a conductive pattern.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a substrate having a conductive pattern, a method for manufacturing an electronic device, a method for manufacturing an electromagnetic wave shielding film, a method for manufacturing a sheet heating element, and a substrate having a conductive pattern. More specifically, the present invention relates to a method for manufacturing a substrate having a conductive pattern using a conductive composition containing conductive particles. [Background technology]

[0002] A known technique involves forming a pattern on a substrate using a conductive composition containing conductive particles and then heating the pattern to obtain a conductive pattern. This technique is thought to be applicable to printed electronics, which has been actively developed in recent years. Printed electronics is a technology that uses printing technology to form electronic circuits, sensors, elements, etc. on a substrate such as a film.

[0003] Patent Document 1 discloses a method for manufacturing a wiring board, which includes the steps of forming grooves for a circuit pattern in an insulating film using a laser processing machine, applying a conductive paste made by dispersing ultrafine particles of a conductive material in a solvent onto the insulating film, removing the solvent from the applied conductive paste by heat treatment and firing the ultrafine particles of the conductive material, and polishing the surface of the insulating film.

[0004] Patent Document 2 discloses a method for manufacturing a printed wiring board, which includes the steps of: forming an uncured resin layer of uniform thickness on a substrate; curing the uncured resin layer while pressing a relief plate against the surface of the uncured resin layer so that the relief plate is parallel to the substrate; peeling the relief plate from the cured resin layer on the substrate to form grooves on the surface of the resin layer; filling a conductive paste into the grooves in the resin layer to form conductor wiring; forming an extraction conductor portion that covers the conductor wiring and a predetermined portion on the surface of the resin layer; and forming a protective coat that covers the entire conductor wiring and a predetermined portion of the conductor portion.

[0005] Patent Document 3 discloses a method for manufacturing a wiring board, characterized by comprising the steps of: pressing a mold having a plate surface including convex portions formed according to a desired wiring pattern against a softened insulating sheet; releasing the mold from the hardened insulating sheet to form concave portions according to the wiring pattern; filling the concave portions with a conductive material to form wiring; performing a removal process on the upper surface of the wiring to remove a portion of the upper surface of the wiring and make the height of the upper surface of the wiring lower than the height of the main surface of the insulating sheet; and forming the insulating protective layer on the upper surface of the wiring so that it is at approximately the same height as the insulating sheet.

[0006] Patent Document 4 discloses a method for forming a conductor pattern of an electronic component, which comprises a step of preparing a resin intaglio plate having projections and depressions corresponding to the conductor pattern, and a step of forming a conductor pattern by filling the resin intaglio plate with a conductive paste and transferring the pattern of the conductive paste filled in the resin intaglio plate to a ceramic substrate, wherein the step of preparing the resin intaglio plate comprises a first step of preparing a master mold and a second step of filling the master mold with resin and curing it. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-200236 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-253432 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-161951 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-068555 Summary of the Invention [Problem to be solved by the invention]

[0008] In principle, the formation of a conductive pattern using a conductive composition containing conductive particles is disadvantageous in terms of forming a fine circuit pattern or a high-precision circuit pattern compared to pattern formation by photolithography or etching. However, due to the increasing expectations for cost reduction in circuit pattern formation and printed electronics suitable for mass production, there is a growing demand for the formation of a fine circuit pattern or a high-precision circuit pattern even in the formation of a conductive pattern using a conductive composition.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to form a fine circuit pattern and / or a high-precision circuit pattern when forming a conductive pattern using a conductive composition containing conductive particles. [Means for solving the problem]

[0010] The present inventors have completed the invention provided below and solved the above problems.

[0011] 1. a hole filling step of filling recesses provided on the surface of the substrate with a conductive composition containing conductive particles to obtain a hole-filled pattern; a pressing step of applying at least pressure to the hole filling pattern to obtain a conductive pattern; A method for manufacturing a substrate having a conductive pattern, comprising: 2. 1. A method for manufacturing a substrate having the conductive pattern according to claim 1, A method for manufacturing a substrate having a conductive pattern, comprising a removing step of removing at least a portion of the excess conductive composition that was not filled in the recesses in the filling step after the filling step and before the pressing step. 3. 2. A method for manufacturing a substrate having a conductive pattern according to the present invention, The method for manufacturing a substrate provided with a conductive pattern, wherein the removing step is carried out by scraping off the excess conductive composition. 4. A method for manufacturing a substrate provided with the conductive pattern according to any one of 1. to 3., In the hole filling step, the recesses are filled with the conductive composition by a printing method. 5. 4. A method for manufacturing a substrate having the conductive pattern according to claim 4, The method for producing a substrate provided with a conductive pattern, wherein the printing method is a screen printing method, an inkjet printing method or a dispenser printing method. 6. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 5., A method for manufacturing a substrate having a conductive pattern, wherein the substrate comprises at least a substrate layer and a pattern layer made of a material different from the substrate layer and provided on at least one side of the substrate layer, and a recess is formed in the pattern layer. 7. 6. A method for manufacturing a substrate having the conductive pattern according to claim 6, A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed from a curable resin material. 8. 7. A method for manufacturing a substrate having the conductive pattern according to claim 7, In the hole filling step, the curable resin material forming the pattern layer is in an uncured or semi-cured state. 9. 7. or 8. A method for manufacturing a substrate having a conductive pattern, comprising: A method for manufacturing a substrate provided with a conductive pattern, comprising, before the pressing step, a curing step of curing the curable resin material forming the pattern layer. 10. A method for manufacturing a substrate having a conductive pattern according to any one of 7. to 9., A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by forming a film made of a curable resin material on the surface of a support having convex portions and attaching the film to the substrate layer. 11. A method for manufacturing a substrate having a conductive pattern according to any one of 7. to 9., A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by pressing a stamper against a film formed on at least one side of the substrate layer using the curable resin material. 12. A method for manufacturing a substrate having a conductive pattern according to any one of 7. to 9., A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by irradiating a film formed on at least one side of the substrate layer using the curable resin material with laser light. 13. A method for manufacturing a substrate provided with the conductive pattern according to any one of 6. to 12., A method for manufacturing a substrate having a conductive pattern, wherein the thickness of the substrate layer is 30 μm or more. 14. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 5., The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses directly formed thereon. 15. A method for manufacturing a substrate provided with the conductive pattern according to any one of 1. to 6., The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses formed directly on the resin film by irradiating the resin film with laser light. 16. A method for manufacturing a substrate provided with the conductive pattern according to any one of 1. to 6., The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses formed directly thereon by a thermal imprinting method. 17. A method for manufacturing a substrate having a conductive pattern according to any one of items 14 to 16, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the thickness of the substrate is 30 μm or more. 18. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 17., a step of removing an oxide film, after the filling step and before or simultaneously with the pressing step, of penetrating a component X capable of removing an oxide film on the surface of the conductive particles into the filling pattern. 19. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 18., In the pressing step, the hole filling pattern is pressed while being heated. 20. 19. A method for manufacturing a substrate having a conductive pattern according to claim 19, A method for manufacturing a substrate provided with a conductive pattern, wherein in the pressing step, the filling pattern is pressed with a pressure of 1 to 500 MPa and heated at a temperature of 80 to 400°C. twenty one. A method for manufacturing a substrate provided with the conductive pattern according to any one of 1. to 20., The method for manufacturing a substrate having a conductive pattern, wherein the conductive composition is in a paste state at room temperature. twenty two. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 21., The method for producing a substrate having a conductive pattern, wherein the amount of the resin component in the conductive composition is 15 parts by mass or less per 100 parts by mass of the conductive particles. twenty three. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 22., A method for producing a substrate having a conductive pattern, wherein the conductive composition does not substantially contain a curable component as a component other than the conductive particles. twenty four. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 23., The particle diameter D at which the cumulative frequency reaches 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method.50 A method for producing a substrate provided with a conductive pattern, wherein the thickness is 0.5 to 100 μm. twenty five. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 24., In the pressing step, the exposed surface of the filling pattern is covered with a member, and then the filling pattern is at least pressed. 26. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 25., A method for manufacturing a substrate having a conductive pattern, wherein the cross-sectional shape of the recess is reverse tapered in a direction away from the substrate. 27. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 26., A method for producing a substrate provided with a conductive pattern, wherein the recesses have a depth of 3 to 100 μm. 28. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 27., The method for manufacturing a substrate having a conductive pattern, wherein the substrate is flexible. 29. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 28., A method for manufacturing a substrate having a conductive pattern, wherein the substrate includes at least one selected from the group consisting of polyester, polyolefin, polycarbonate, polyimide, and paper. 30. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 28., A method for manufacturing a substrate having a conductive pattern, wherein the substrate contains a foamed resin. 31. A method for manufacturing a substrate having a conductive pattern according to any one of 1. to 30., A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer contains a filler that changes the dielectric constant of the pattern layer or increases the electromagnetic wave absorption properties of the pattern layer. 32. A method for manufacturing an electronic device, comprising manufacturing an electronic device using a substrate having a conductive pattern obtained by the method for manufacturing a substrate having a conductive pattern according to any one of 1. to 31. 33. 32. A method for producing an electronic device according to claim 32, comprising the steps of: The method for manufacturing an electronic device, wherein the electronic device is an RF tag. 34. A method for producing an electromagnetic wave shielding film, comprising producing an electromagnetic wave shielding film using a substrate having a conductive pattern obtained by the method for producing a substrate having a conductive pattern according to any one of 1. to 31. 35. A method for producing a sheet heating element, comprising producing a sheet heating element using a substrate having a conductive pattern obtained by the method for producing a substrate having a conductive pattern described in any one of 1. to 31. 36. a substrate having a recessed portion on its surface; a conductive pattern formed by sintering conductive particles in the recess; A substrate provided with a conductive pattern. 37. A substrate provided with a conductive pattern according to claim 36, The substrate is a substrate with a conductive pattern, which comprises at least a substrate layer and a pattern layer made of a material different from the substrate layer and provided on at least one side of the substrate layer, and in which a recess is formed in the pattern layer. 38. 37. A substrate provided with a conductive pattern according to claim 37, A substrate provided with a conductive pattern, wherein the pattern layer is formed from a cured product of a curable resin material. 39. A substrate having a conductive pattern according to 37. or 38., A substrate provided with a conductive pattern, wherein the thickness of the substrate layer is 30 μm or more. 40. A substrate provided with the conductive pattern according to any one of 36 to 39, The particle diameter D at which the cumulative frequency reaches 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method. 50 A substrate having a conductive pattern, wherein the thickness is 0.5 to 100 μm. 41. A substrate provided with the conductive pattern according to any one of 36 to 40, A substrate provided with a conductive pattern, wherein the cross-sectional shape of the conductive pattern is reverse tapered in a direction away from the substrate. 42. A substrate provided with the conductive pattern according to any one of 36 to 41, A substrate provided with a conductive pattern, wherein the depth of the recesses in the pattern layer is 3 to 100 μm. 43. A substrate provided with the conductive pattern according to any one of 36. to 42., The substrate is flexible and has a conductive pattern. 44. A substrate provided with the conductive pattern according to any one of 36. to 43., The substrate is provided with a conductive pattern and includes at least one selected from the group consisting of polyester, polyolefin, polycarbonate, polyimide, and paper. 45. A substrate provided with the conductive pattern according to any one of 36. to 44., The substrate includes a foamed resin and is provided with a conductive pattern. 46. A substrate provided with the conductive pattern according to any one of items 35 to 44, A substrate provided with a conductive pattern, wherein the pattern layer contains a filler that changes the dielectric constant of the pattern layer or increases the electromagnetic wave absorption property of the pattern layer. [Effects of the Invention]

[0012] According to the present invention, when a conductive pattern is formed using a conductive composition containing conductive particles, a fine circuit pattern and / or a highly accurate circuit pattern can be formed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram for explaining a first embodiment. [Figure 2] FIG. 1 is a diagram for explaining a first embodiment. [Figure 3] FIG. 10 is a diagram for explaining a second embodiment. [Figure 4] FIG. 10 is a diagram for explaining a second embodiment. [Figure 5] FIG. 10 is a diagram for explaining a third embodiment. [Figure 6] FIG. 10 is a diagram for explaining a third embodiment. [Figure 7] FIG. 10 is a diagram for explaining a fourth embodiment. [Figure 8] FIG. 10 is a diagram for explaining a fourth embodiment. [Figure 9] FIG. 10 is a diagram illustrating a fifth embodiment. [Figure 10] FIG. 10 is a diagram illustrating a fifth embodiment. [Figure 11] 1 is an enlarged image of a conductive pattern portion of a substrate provided with a conductive pattern obtained in Example 1. [Figure 12] 1 is an enlarged image of a conductive pattern portion of a substrate provided with a conductive pattern obtained in Example 2. [Figure 13] 1 is an enlarged image of a cross section of a substrate provided with a conductive pattern obtained in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, similar components are denoted by similar reference numerals and descriptions thereof will be omitted where appropriate. To avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them is given a symbol, and not all of them, or (ii) particularly in Figure 2 and subsequent figures, components similar to those in Figure 1 are not given a symbol again. All drawings are for illustrative purposes only, and the shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0015] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0016] In this specification, the term "(meth)acrylic" represents a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." In this specification, the term "electronic device" is used to encompass elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

[0017] <Method for manufacturing a substrate with a conductive pattern: Overview> The method for manufacturing a substrate having a conductive pattern of this embodiment includes the steps of: a hole filling step of filling recesses provided on the surface of the substrate with a conductive composition containing conductive particles to obtain a hole-filled pattern; a pressing step of applying at least pressure to the hole-filling pattern to obtain a conductive pattern; Includes.

[0018] In this embodiment, at least pressure is applied to the pattern formed from the conductive composition in the pressing step to increase the conductivity of the pattern and obtain a conductive pattern. However, if the pattern formed from the conductive composition is simply pressed, there is a concern that the pattern may be deformed, making it impossible to obtain a thin conductive pattern or a high-precision conductive pattern (close to the intended dimensions and shape). In consideration of this concern, in this embodiment, (i) a recess provided on the surface of a substrate is filled with a conductive composition containing conductive particles to obtain a hole-filled pattern, and (ii) at least pressure is applied to the hole-filled pattern. In this manner, pressure is applied to the pattern formed by the conductive composition containing conductive particles while at least a portion of the pattern is present in the recess. In this case, deformation of the pattern when pressure is applied to the pattern is limited, making it easier to obtain a thin conductive pattern or a high-precision conductive pattern (close to the intended dimensions and shape). In other words, because the side surfaces of the recesses become "walls" for the hole-filled pattern, deformation of the hole-filled pattern is limited.

[0019] The above is an outline of the method for manufacturing a substrate provided with a conductive pattern according to this embodiment. As more specific embodiments, first to fifth embodiments will be described below.

[0020] <Method for manufacturing a substrate provided with a conductive pattern: First embodiment (FIGS. 1 and 2)> 1 and 2 are diagrams for explaining a method for manufacturing a substrate having a conductive pattern according to the first embodiment. Hereinafter, the method for manufacturing a substrate having a conductive pattern according to the first embodiment will be described with reference to FIGS. 1 and 2.

[0021] FIG. 1 illustrates a series of steps for obtaining a substrate having recesses on its surface. 1, a substrate (pattern layer 2B having a recess) can be obtained (FIG. 1A5) that includes at least a substrate layer 1 and a pattern layer 2B made of a material different from that of substrate layer 1 and provided on at least one side of substrate layer 1. The recess is located between two protrusions in pattern layer 2B.

[0022] Each step will be explained below.

[0023] (Figure 1A1: Preparation of support 30 (plate)) FIG. 1A1 schematically shows a support 30 having protrusions for providing recesses on the surface of a substrate. The support 30 is typically an intaglio plate. In Fig. 1A1, a convex portion exists between two concave portions. However, the support 30 may be a relief plate as long as it is possible to form the desired pattern layer 2. Specifically, the support 30 may be like the support 30 in Fig. 3A2. The support 30 can be produced by referring to the method of producing an intaglio plate in gravure printing or other intaglio printing techniques. Specific intaglio plate production methods include laser platemaking and electroforming. By appropriately designing the shape of the convex and / or concave portions of the support 30 (plate), it is possible to produce a substrate having a desired conductive pattern. Considering the ease of manufacturing the support 30 and the ease of peeling in FIG. 1A5, which will be described later, it is preferable that the cross-sectional shape of the recess in the support 30 be inverted tapered, that is, a shape in which the width of the recess increases from the bottom to the outside. In FIG. 1A1, an example of a recess having an inverted tapered cross-sectional shape is a recess having a semicircular or arc-shaped cross-sectional shape. Of course, the cross-sectional shape may also be composed of straight lines. It is also preferable that the cross-sectional shape of the protrusion in the support 30 be tapered.

[0024] (Figure 1A2: Film formation using pattern layer forming material) Fig. 1A2 shows that a film 2 made of a material for forming a pattern layer is formed on the surface of the support 30 shown in Fig. 1A1 where the protrusions are located. The material for forming a pattern layer is usually a material different from the base layer 1 shown in Fig. 1A3.

[0025] The method for forming the film is not particularly limited. Various coating methods and printing methods are applicable. From the viewpoint of thickness reproducibility and uniform film formation, it is preferable to form the film 2 using an applicator. Of course, the film 2 may also be formed by a method other than a method using an applicator. The film 2 may also be formed by attaching a film- or sheet-like material for forming a pattern layer. In consideration of the bonding of the film 2 to the base layer 1, which will be described later, it is preferable that the exposed surface of the film 2 is substantially flat.

[0026] The material for forming the pattern layer is preferably a curable resin material. The curable resin material is typically thermosetting and / or photocurable. The curable resin material may have both thermosetting and photocurable properties, or may have only one of thermosetting and photocurable properties. Specific examples of the curable resin material include epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials.

[0027] (FIG. 1A3: Attachment of film 2 to base layer 1) 1A3 shows that a base layer 1 is bonded to the film 2 formed in FIG. 1A2. Specifically, the film 2 made of a curable resin material formed on the surface of the support 30 is bonded to the base layer 1. At this time, pressing may or may not be performed with the intention of increasing adhesion. Specific pressing means include pressing using a roller or pressing using a flat press device.

[0028] The base layer 1 is usually in the form of a film, sheet or plate, and from the viewpoint of industrial productivity, the base layer 1 is preferably in any of these forms. The base material layer 1 is preferably flexible. By employing a flexible base material layer 1, a flexible printed circuit (FPC) can be manufactured. By using a flexible base material layer 1, pressing using a "roll" becomes easier in the pressing step described below. This is preferable from the viewpoint of mass productivity. Just to be clear, the base material layer 1 may be a rigid base material that does not have flexibility.

[0029] Considering cost and end use, the substrate layer 1 is preferably at least one selected from the group consisting of polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyolefins such as polyethylene and polypropylene, polycarbonate, polyimide, and paper. Here, the paper may be coated paper (paper whose surface is coated with a coating agent) or ordinary uncoated paper. Furthermore, the substrate layer 1 is not limited to PET and other materials, and any general resin film can be used. Furthermore, the substrate layer 1 may be transparent or opaque. Examples of opaque resin films include those containing foamed resins, specifically, foamed resin films such as foamed PET films or foamed resin sheets. In the first embodiment, a conductive pattern with sufficiently low resistivity can be obtained without heating or by heating at a relatively low temperature in the pressing step. Therefore, a low-heat-resistant substrate layer 1 made of polyester, polyolefin, polycarbonate, paper, or the like can also be suitably used as the substrate layer. Furthermore, when a highly heat-resistant substrate layer 1 such as polyimide is used, the resistivity of the resulting conductive pattern can be further reduced by performing high-temperature heating in the pressing step.

[0030] The thickness of the substrate layer 1 is not particularly limited and can be appropriately set depending on the final application (electronic device, RF tag, electromagnetic wave shielding film, planar heating element, etc.) described below and various other circumstances. The thickness of the substrate layer 1 is, for example, 10 μm or more, preferably 30 μm or more. More specifically, the thickness of the substrate layer 1 is typically 10 to 250 μm, preferably 30 to 100 μm. However, from the viewpoint of suppressing curling due to shrinkage of the pattern layer, it is preferable that the substrate layer 1 be somewhat thick. Specifically, the thickness of the substrate layer 1 is preferably 100 to 250 μm, more preferably 100 to 150 μm. The base layer 1 may have a single layer structure or a laminate structure of two or more layers.

[0031] (Figure 1A4: Hardening of Membrane 2) When the film 2 is made of a curable resin material, the curable resin material can be cured or semi-cured to form the pattern layer 2B by applying an appropriate external stimulus (typically heat or light, preferably ultraviolet light) to the film 2. This can improve the adhesion between the base layer 1 and the pattern layer 2B. Also, from the viewpoint of the effect of the side surfaces of the recesses becoming "walls" as mentioned above, it is preferable to cure or semi-cure the film 2. When curing or semi-curing the curable resin material by heating, the heating temperature and time are not particularly limited as long as the curable resin material is properly cured or semi-cured. However, taking into account the heat resistance of the base layer 1, care should be taken to avoid excessively high temperatures or long heating times. When curing or semi-curing the curable resin material with light (preferably ultraviolet light), the wavelength and irradiation amount of light are not particularly limited as long as the curable resin material is appropriately cured or semi-cured. If the base layer 1 is light-transmitting, light may be irradiated through the base layer 1. Similarly, if the support 30 is light-transmitting, light may be irradiated through the support 30.

[0032] In the case where the degree of curing of the film 2 is to be limited to a semi-cured state, it is preferable to completely cure the pattern layer 2B by additionally heating or irradiating with light before performing the pressing (FIG. 2B4) described later. The same applies to other embodiments described later.

[0033] (Figure 1A5: Separation) The laminate of the base material layer 1 and the pattern layer 2B obtained up to Fig. 1A4 is separated from the support 30. This makes it possible to obtain a base material having recesses on its surface. The separation method is not particularly limited as long as damage to the base material layer 1 and the pattern layer 2B is suppressed.

[0034] The thickness of the substrate thus obtained, i.e., the laminate of substrate layer 1 and pattern layer 2B, is preferably 30 μm or more, more preferably 30 to 300 μm, and even more preferably 30 to 200 μm, taking into consideration durability, final use, etc. Here, the "thickness" refers to the thickness of the portion of the substrate where no recesses are provided (the thickest portion of the substrate), i.e., the sum of the thickness of the protruding portions of pattern layer 2B and the thickness of substrate layer 1.

[0035] The cross-sectional shape of the recesses provided in the substrate, more specifically, the recesses provided in the pattern layer 2B of the substrate, is preferably inversely tapered in the direction away from the substrate. Such a cross-sectional shape of the recesses is preferable because it makes it easier to concentrate the conductive particles in the recesses without leaving any gaps in the hole filling step described below. In FIG. 1, two or more semicircular protrusions are provided in the pattern layer 2B, so that the recess between the two protrusions is inversely tapered in the direction away from the substrate. The depth of the recesses is not particularly limited and may be set appropriately taking into consideration the final use, etc. The depth of the recesses is preferably 3 to 100 μm, more preferably 10 to 50 μm, and even more preferably 10 to 30 μm.

[0036] The pattern layer 2B may contain a filler that changes the dielectric constant of the pattern layer 2B or increases the electromagnetic wave absorption of the pattern layer 2B. That is, the pattern layer 2B may be formed from a curable resin material that contains a filler that has characteristic electrical / magnetic properties. Inclusion of such a filler in the pattern layer 2B may improve the performance of the substrate having the final conductive pattern or may add new functions to the final conductive pattern.

[0037] An example of the filler is a low dielectric constant filler, which preferably has a low dielectric constant and a low dielectric loss tangent. The use of a low-dielectric filler can lower the dielectric constant of the substrate, which can reduce transmission delay and loss in high-speed transmission in high-frequency bands such as millimeter waves when the final substrate with a conductive pattern is used as an antenna. A specific example of the low dielectric constant filler is glass flakes, etc. Low dielectric glass flakes are available commercially from, for example, Nippon Sheet Glass Co., Ltd.

[0038] Another example of the filler is a high dielectric constant filler, which preferably has a high dielectric constant and a low dielectric loss tangent. When the final substrate with a conductive pattern is used as an antenna, the use of a high-dielectric filler can reduce the decrease in communication distance even if the antenna size is reduced. This is because the high-dielectric filler has a wavelength shortening effect, making it possible to resonate even if the antenna size (antenna length) is reduced. Specific examples of high dielectric constant fillers include calcium titanate, strontium titanate, etc. Calcium titanate and strontium titanate are commercially available from Kyoritsu Material Co., Ltd., for example.

[0039] Another example of the filler is an electromagnetic wave absorbing filler. When the final substrate with the conductive pattern is applied to an RF tag, it is believed that communication will be possible even if the substrate with the conductive pattern (RF tag) is directly attached to metal if the substrate (pattern layer 2B) contains an electromagnetic wave absorbing filler. Examples of electromagnetic wave absorbing fillers include soft magnetic powders, specifically soft magnetic flake powders. More specifically, Fe-Si-Al alloys are available. Such electromagnetic wave absorbing fillers are commercially available from, for example, Sanyo Special Steel Co., Ltd.

[0040] (Figure 2B1: Fill in the blank) In Fig. 2B1, at least the recesses of pattern layer 2B of the substrate obtained in Fig. 1 are filled with a conductive composition containing conductive particles. This allows for the formation of hole-filled pattern 3B. Here, "filling" the recesses with the conductive composition includes not only (i) filling the recesses up to or above the top with the conductive composition, but also (ii) using a relatively small amount of conductive composition to fill the lower part of the recesses with the conductive composition but not the upper part of the recesses with the conductive composition. 2B1 shows how a conductive composition is filled into at least the recesses of the pattern layer 2B of the substrate using a doctor blade 40 to form a hole-filling pattern 3B. Note that the specific hole-filling method is not limited to the method using the doctor blade 40 shown here, and various printing methods can also be applied. This will be described in detail in the third embodiment.

[0041] After the filling step described here and before the pressing step described later, a removal step may be performed to remove at least a portion of the excess conductive composition that was not filled in the recesses during the filling step. Here, the "excess" conductive composition refers to both (i) the conductive composition that has accumulated higher than the protrusions on the top of the recesses, and (ii) the conductive composition that is present in areas other than the recesses (such as the protrusions and flat areas). The removal can be performed by scraping off the excess conductive composition using, for example, a doctor blade. Incidentally, in consideration of the fact that the filling pattern 3B will be "pressed" by the pressure in the subsequent pressing step (FIG. 2B4), it may be possible to intentionally leave the conductive composition deposited higher than the protrusions on the top of the recesses. In this case, the removal step may not be necessary.

[0042] At this stage, it is preferable that the conductive particles in the filling pattern 3B are not substantially sintered. Incidentally, the conductive particles can usually be sintered in the pressing step described later. The conductive composition is preferably in a paste form at room temperature (for example, 25° C.) from the viewpoint of ease of pattern formation and shape retention. From the viewpoint of further increasing the conductivity of the finally obtained conductive pattern, the amount of the resin component in the conductive composition is preferably 15 parts by mass or less, i.e., 0 to 15 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 5 parts by mass, per 100 parts by mass of the conductive particles. The remaining component in the conductive composition is preferably conductive particles. If there is no problem with pattern formability, the conductive composition may not contain a resin component. From the viewpoint of improving conductivity, it is preferable that the conductive composition does not substantially contain a curable component other than the conductive particles. On the other hand, from the viewpoint of improving the printability and coatability of the conductive composition, the conductive composition may contain a resin component such as a resin or a binder. From the viewpoint of fully obtaining the effects of using the resin component, the amount of the resin component in the conductive composition is preferably 1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the conductive particles. The remaining component in the conductive composition is preferably the conductive particles. In particular, when the final conductive pattern is provided on a paper substrate, the amount of the resin component may be relatively large, taking into consideration that the resin component will penetrate into the paper substrate. In this case, the amount of the resin component in the conductive composition is preferably 5 to 30 parts by mass, and more preferably 10 to 20 parts by mass, per 100 parts by mass of the conductive particles. Specific examples of resin components that can be contained in the conductive composition include polyvinylpyrrolidone, polyester, epoxy resin, phenoxy resin, (meth)acrylic resin, polyvinyl acetal, cellulose resin (e.g., ethyl cellulose), and phenol resin.

[0043] The conductive composition may contain a solvent. When the conductive composition contains a solvent, the conductive composition can be easily applied or printed onto a substrate. The solvent typically contains an organic solvent. The solvent may contain water as long as the conductive particles can be appropriately dispersed in the solvent. The type of solvent is not particularly limited, as long as it does not substantially alter the components in the conductive composition. The amount of the solvent used may be adjusted as appropriate depending on the specific method for embedding the conductive composition, etc. The amount of the solvent used is, for example, 3 to 30 mass %, preferably 5 to 25 mass %, and more preferably 10 to 20 mass % of the total conductive composition.

[0044] The conductive particles contained in the conductive composition preferably contain at least one element selected from the group consisting of silver and copper, from the viewpoints of availability and good conductivity. Specifically, the conductive particles preferably include at least one selected from the group consisting of particles primarily composed of silver and particles primarily composed of copper. Here, the expression "primarily composed of silver" means that the ratio of silver element to all constituent elements in the particles is preferably 50 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. Similarly, the expression "primarily composed of copper" means that the ratio of copper element to all constituent elements in the particles is preferably 50 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. Just to be clear, the conductive particles may contain elements other than silver and copper as long as the desired conductivity is obtained. Examples of elements other than silver and copper include gold, aluminum, platinum, palladium, iridium, tungsten, nickel, tantalum, lead, and zinc. Of course, the conductive particles do not have to be substantially free of elements other than silver and copper. "Substantially free" means that the conductive particles may unavoidably contain elements other than silver and copper as impurities, but they do not intentionally or artificially contain elements other than silver and copper.

[0045] The conductive particles may contain only one element, or may contain two or more elements. For example, conductive particles in which the surface of copper particles is silver-plated (silver-coated copper particles) are preferably used in this embodiment. Silver-coated copper particles are particles whose main component is copper, and the surface of the copper particles is plated with silver in an amount of, for example, up to 35 mass% based on the total mass of the particles.

[0046] The particle diameter D at which the cumulative frequency reaches 50% in the volume-based cumulative particle diameter distribution curve obtained when the particle diameter of conductive particles is measured by the laser diffraction scattering method. 50 is preferably 0.5 to 100 μm, more preferably 0.6 to 50 μm, even more preferably 0.7 to 30 μm, and particularly preferably 0.7 to 20 μm. D 50 By making the ρ appropriately large, the number of grain boundaries between conductive particles per unit volume can be reduced, which is thought to lead to a smaller specific resistance of the resulting conductive pattern. D 50 It is believed that by not making the size too large, the "gaps" between the conductive particles are reduced, which leads to a smaller specific resistance of the resulting conductive pattern.

[0047] Conductive particles can be purchased from, for example, DOWA Electronics Co., Ltd., Fukuda Metal Foil and Powder Co., Ltd. Two or more different conductive particles may be mixed together for the purpose of adjusting or optimizing the particle size distribution or for other purposes.

[0048] From the viewpoint of further reducing the resistivity of the final conductive pattern, it is preferable that the proportion of conductive particles in the conductive composition is high. Specifically, the proportion of conductive particles in the total non-volatile components of the conductive composition is preferably 95% by mass or more, more preferably 97% by mass or more, even more preferably 98% by mass or more, and particularly preferably 99% by mass or more. In other words, from the viewpoint of further reducing the resistivity of the resulting conductive pattern, it is preferable that the conductive composition is substantially free of resin components such as resins and binders. Here, "substantially free of resin components" means that the composition does not contain any resin components at all, or that the amount of resin components contained is so small that the expected effect of using the resin components cannot be obtained (for example, 1% by mass or less, specifically 0.5% by mass or less, of the total non-volatile components of the conductive composition). The conductive composition does not need to contain resins or binders as long as the desired conductive pattern can be obtained.

[0049] The conductive composition may or may not contain various additive components found in conventional ink compositions and conductive pastes.

[0050] (Figure 2B2: Drying) If the conductive composition used in Fig. 2B1 contains a solvent, it is preferable to volatilize the solvent by heat treatment. The drying conditions are not particularly limited. The temperature and time may be set so as not to damage or deteriorate the substrate.

[0051] (Figure 2B3: Oxide film removal) In the first embodiment, it is preferable to infiltrate the filling pattern 3B with a component X capable of removing oxide films on the surfaces of the conductive particles in the filling pattern 3B before or simultaneously with the pressing step described below into the filling pattern 3B. By doing so, the sintering of the conductive particles tends to proceed more easily during the pressing step described below, and the conductivity of the finally obtained conductive pattern tends to be further increased.

[0052] It is preferable that component X penetrates into the embedded pattern (pattern 3B) through the gaps between the conductive particles that make up the embedded pattern (pattern 3B). This tends to further increase the conductivity of the finally obtained conductive pattern. For this reason, in the oxide film removal step, the embedded pattern (pattern 3B) in contact with component X may be pressed to promote penetration of component X into the embedded pattern (pattern 3B). In this case, the oxide film removal step and the pressing step described below may be performed simultaneously. Of course, the oxide film removing step may be performed as a separate step from the pressing step.

[0053] The oxide film removal step can be performed, for example, as shown in Fig. 2B3, by contacting and preferably penetrating the filling pattern 3B with a liquid 7 containing component X, which is capable of removing oxide films on the surfaces of conductive particles. Fig. 2B3 shows an embodiment in which the liquid 7 containing component X is dropped or sprayed onto the filling pattern 3B, but the filling pattern 3B may also be immersed in the liquid containing component X. Alternatively, the liquid 7 containing component X may be brought into contact with the filling pattern 3B using an inkjet method or a dispenser method. The liquid 7 containing component X is preferably water in which component X is dissolved or dispersed. The use of water is preferable from the viewpoints of reducing the environmental load and process safety (non-flammability). Of course, an organic solvent in which component X is dissolved or dispersed can also be used. Instead of using the liquid 7 containing the component X, the oxide film removing step may be carried out by bringing the component X in a gaseous state into contact with the filling pattern 3B. Alternatively, a sheet containing component X may be brought into contact with filling pattern 3B, preferably by applying pressure, to cause component X to penetrate into filling pattern 3B. Specific examples of the sheet include paper or nonwoven fabric containing component X, and resin sheets having component X coated or printed on their surfaces. Additionally, the method for bringing the component X into contact with the filling pattern 3B and allowing it to penetrate therein is not particularly limited.

[0054] Component X is not particularly limited as long as it is capable of removing the oxide film on the surface of the conductive particles. In this specification, "removal" of an oxide film includes not only the removal of the oxide itself present on the surface of a conductive particle, but also the case where the oxide undergoes a chemical change such as reduction, thereby returning the oxide to a non-oxide.

[0055] According to the findings of the present inventors, it is preferable to include at least one selected from the group consisting of organic acids, phosphorus oxoacids, and hydrazine or its derivatives, which are particularly suitable when the conductive particles include copper or silver.

[0056] Examples of organic acids include carboxylic acids such as citric acid, formic acid, acetic acid, malonic acid, malic acid, tartaric acid, ascorbic acid, succinic acid, fumaric acid, and propionic acid. Specific examples of phosphorus oxoacids include phosphinic acid, phosphonic acid, phosphorous acid, phosphoric acid, diphosphoric acid, triphosphoric acid, and metatriphosphoric acid. Of these, phosphinic acid is particularly preferred. Examples of hydrazine or its derivatives include hydrazine itself; hydrazine salts such as hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine monohydrobromide, and hydrazine sulfate; and other compounds having an -NH-NH2 structure.

[0057] Additionally, from the viewpoint of removing an oxide film, a compound having a small pKa in water can be used as component X. Specifically, a compound having a pKa in water of -5.0 to 5.0 is preferred as component X, and a compound having a pKa of -4.0 to 4.5 is more preferred as component X. Incidentally, when component X is a polybasic acid, it is preferred that the smallest pKa among the multiple pKas is within the above range. Considering only the small pKa and the resulting ability to remove oxide films, it is conceivable to use an inorganic acid such as hydrochloric acid, nitric acid, or sulfuric acid as component X. However, taking into consideration the inconvenience that may occur if the acid remains in pattern 3B, an organic acid is preferred as component X. The pKa value used here can be the value at room temperature (e.g., 25°C). However, from the viewpoint of the removability of the oxide film in the actual process, it can be said that it is preferable to use the pKa value at the temperature in the penetration step or conductive film formation step.

[0058] Additionally, any compound capable of returning an oxide film to a non-oxidized state by a reduction reaction can also be used as component X. For example, a compound having an aldehyde group can be used as component X because it may be able to reduce an oxide.

[0059] Furthermore, compounds that have a small pKa in water and can return an oxidized film to a non-oxidized state through a reduction reaction are also preferably used as component X. An example of such a compound is formic acid. Formic acid has the advantage that it is easily volatile and therefore does not easily remain in the pattern.

[0060] In addition to the above, examples of component X include pyrogallol, phenidone, hydroquinone, and orthoaminophenol, which are known to function as reducing agents in the field of silver halide photography. If a conductive pattern having a lower resistivity is obtained when a certain compound A is infiltrated into the hole filling pattern 3B compared to when it is not infiltrated, then the compound A can be adopted as component X.

[0061] When the liquid in which the component X is dissolved or dispersed is brought into contact with the filling pattern 3B, the concentration of the component X in the liquid may be adjusted appropriately from the viewpoints of allowing a sufficient amount of the component X to penetrate into the filling pattern 3B and reducing the amount of the remaining component X to suppress corrosion or deterioration of the conductive pattern. The concentration of component X in the liquid is, for example, 0.05 to 50 mol / L, preferably 0.1 to 40 mol / L, more preferably 0.1 to 30 mol / L, even more preferably 0.1 to 10 mol / L, and particularly preferably 0.15 to 5.0 mol / L. Of course, a liquid containing component X at a concentration lower than the concentrations shown here may be used, or a liquid containing component X at a concentration higher than the concentrations shown here (for example, saturation concentration) may be used.

[0062] When the oxide film removal step is performed, a process for reducing the amount of component X remaining in the filling pattern 3B may be performed. This process can further reduce the resistivity of the finally obtained conductive pattern. This process may be performed before or after the pressing step described below. For example, if the component X has the property of volatilizing when heated, it is conceivable to perform a process of volatilizing the component X remaining in the filling pattern 3B by heating the filling pattern 3B to an appropriate temperature. As another example, it is possible to carry out a process of bringing filling pattern 3B into contact with a liquid such as water to elute component X remaining in filling pattern 3B.

[0063] More specifically, examples of the treatment for reducing the amount of component X remaining in the filling pattern 3B include the following methods (i) to (v). (i) An air flow is applied to the hole filling pattern 3B. (ii) An inert gas such as nitrogen gas is sprayed toward the filling pattern 3B. (iii) A liquid-absorbing member such as a sponge is pressed against filling pattern 3B to absorb the solution or dispersion containing component X. In the continuous process shown in Figure 2, it is preferable to use a roll-shaped sponge as the liquid-absorbing member. After absorbing the solution or dispersion, filling pattern 3B may be brought into contact with a liquid such as water (washed), and then the liquid-absorbing member may be pressed against filling pattern 3B again. (iv) Pressure is applied to the filling pattern 3B using a roll to "squeeze" the solution or dispersion containing component X. The filling pattern 3B may then be brought into contact with a liquid such as water (washed), and the liquid may then be squeezed out again using a roll. By appropriately controlling the pressure and not applying heat when applying pressure, the solution or dispersion containing component X can be squeezed out without sintering the conductive particles in the filling pattern 3B. (v) A combination of two or more of the above (i) to (iv), such as a combination of (i) and (ii), or a combination of (iii) and (iv).

[0064] (Figure 2B4: Pressing) At least pressure is applied to the filling pattern 3B of Figure 2B2 or 2B3. This increases the conductivity of the filling pattern 3B, resulting in a conductive pattern 3C (Figure 2B5). Preferably, the pressure sinters at least a portion of the conductive particles in the filling pattern 3B.

[0065] As shown in FIG. 2B4, the pressure is preferably applied by covering the exposed surface of the filling pattern 3B with a member 9 and then at least pressurizing the filling pattern 3B. For example, the pressure can be applied by sandwiching a laminate of the base layer 1, the pattern layer 2B, the filling pattern 3B, and the member 9 between two opposing rolls 10A and 10B and transporting the laminate between the two rolls. The member 9 is preferably a film-like material. For ease of comparison with FIG. 2B3, the member 9 is not depicted as being in contact with the filling pattern 3B in FIG. 2B4; however, in practice, the pressure and the like are preferably adjusted so that the member 9 is in contact with the filling pattern 3B. (In FIGS. 2B1 and 2B2, the thickness of filling pattern 3B is reduced due to drying of the solvent. Taking this reduction into consideration, the recesses may be filled with a conductive composition to the extent that it slightly overflows at the stage of FIG. 2B1. This makes it easier to make the height of the protrusions and the height of filling pattern 3B approximately the same.)

[0066] 2B4, liquid 7 containing component X, which can remove the oxide film on the surface of the conductive particles as described in FIG. 2B3, is present above filling pattern 3B. In this case, it is thought that component X penetrates into filling pattern 3B by applying pressure, removing the oxide film from the conductive particles, while simultaneously sintering the conductive particles. In other words, FIG. 2B4 can be said to represent a mode in which oxide film removal and pressing are performed simultaneously.

[0067] There are several advantages to using the member 9 when applying pressure. Examples of the advantages include the following: Damage to the roll 10A can be suppressed. Also, it may be possible to suppress the filling pattern 3B from being partially or entirely peeled off and adhering to the roll 10A. Direct contact of the roll 10A with the filling pattern 3B is avoided, making it easier to prevent unintended deformation or collapse of the filling pattern 3B. The member 9 acts as a buffer, making it easier to apply pressure uniformly to the filling pattern 3B. This leads to, for example, an improvement in the yield of the substrate with the final conductive pattern. Furthermore, when oxide film removal and pressing are performed simultaneously, applying pressure uniformly to the filling pattern 3B is also preferable because it leads to the component X penetrating uniformly into the filling pattern 3B.

[0068] From one viewpoint, the material of the member 9 can be the same as that of the base layer 1. That is, the member 9 can be preferably a polyester film such as a PET film. From another viewpoint, in order to prevent peeling or damage to the hole filling pattern 3B, an easily peelable film or release paper can be preferably used as the member 9. A specific example of the easily peelable film or release paper is a resin film whose surface is coated with a silicone resin. From another perspective, the member 9 may be made of a non-resin material such as aluminum foil (metal foil, etc.).

[0069] On the other hand, in order to simplify the manufacturing process and reduce waste by reducing the amount of process materials, pressurization may be performed without using the member 9. Furthermore, when the member 9 is used, it may be used only once or may be used repeatedly.

[0070] While FIG. 2B4 shows an embodiment in which the filling pattern 3B is pressed by two opposing rolls 10A and 10B, it goes without saying that the filling pattern 3B may be pressed by other methods. As one example, the laminate of the base layer 1, pattern layer 2B, filling pattern 3B, and member 9 may be sandwiched between two flat plates and pressed (flat press). As another example, the laminate of the base layer 1, pattern layer 2B, filling pattern 3B, and member 9 may be placed on a flat plate, and a roll may be applied from above to pressurize the filling pattern 3B while rolling. As yet another example, a roll may be applied from below to pressurize the filling pattern 3B while rolling.

[0071] In the pressing step, it is preferable to apply pressure to the filling pattern 3B while heating it, which tends to improve the conductivity of the resulting conductive pattern 3C. Preferably, filling pattern 3B is pressed at a pressure of 1 to 500 MPa and heated at a temperature of 80 to 400° C. More preferably, filling pattern 3B is pressed at a pressure of 5 to 400 MPa and heated at a temperature of 80 to 300° C. Even more preferably, filling pattern 3B is pressed at a pressure of 10 to 300 MPa and heated at a temperature of 80 to 150° C. The lower limit of the pressure may be 30 MPa or 50 MPa. Incidentally, when oxide film removal and pressing are performed simultaneously, the heating temperature is preferably set to a temperature that takes into consideration the volatilization or evaporation of liquid 7 and component X. The lower limit of the temperature, "80°C," described above is a value that takes into consideration the evaporation at an appropriate rate when liquid 7 is a mixture of water and a low-boiling-point alcohol or the like. When pressing is performed using two opposing rolls 10A and 10B as shown in FIG. 2B4, it is preferable to use rolls with built-in heaters that can adjust the temperature.

[0072] The time for the pressing step is not particularly limited. The time can be adjusted and determined appropriately from the viewpoints of improving conductivity through sufficient sintering of the conductive particles and industrial productivity. The time for the pressing step (the time during which the filling pattern 3B is actually pressed) is preferably 1 millisecond to 10 seconds, more preferably 10 milliseconds to 3 seconds, and even more preferably 30 milliseconds to 1 second. This value is a preferable pressing time, particularly when the filling pattern 3B is pressed by two opposing rolls 10A and 10B.

[0073] (Figure 2B5) After the pressing is completed, if member 9 was used, it is removed. Then, a substrate with a conductive pattern can be obtained, which includes substrate layer 1 (substrate) having pattern layer 2B formed on one side thereof, and conductive pattern 3C formed by sintering conductive particles in the recesses of pattern layer 2B.

[0074] <Method for manufacturing a substrate provided with a conductive pattern: Second embodiment (FIGS. 3 and 4)> 3 and 4 are diagrams for explaining a method for manufacturing a substrate having a conductive pattern according to the second embodiment. Hereinafter, the method for manufacturing a substrate having a conductive pattern according to the second embodiment will be described with reference to FIGS. 3 and 4. The second embodiment differs from the first embodiment in terms of the method for producing a substrate having recesses. In the first embodiment, a film is first formed from a material for forming a pattern layer on a support 30 (intaglio) having protrusions, and the film is then bonded to a substrate layer 1. In the second embodiment, a film is first formed from a material for forming a pattern layer on one side of the substrate layer 1, and a support 30 (intaglio) having protrusions is pressed against the film to produce a substrate having recesses. A more specific explanation will be given below.

[0075] (FIG. 3A1: Film formation on base layer 1) FIG. 3A1 shows that a film 2 is formed from a material for forming a pattern layer on one side of a base layer 1. The material for forming a pattern layer is usually a different material from the base layer 1 in FIG. 3A1. From the viewpoint of thickness reproducibility and uniform film formation, it is preferable to form the film 2 using an applicator. Of course, the film 2 may also be formed by a method other than using an applicator. The film 2 may also be formed by attaching a film- or sheet-like material for forming a pattern layer to one side of the base layer 1.

[0076] The specific aspects of the base material layer 1 are as explained in the first embodiment, and therefore will not be explained again.

[0077] The material for forming the pattern layer is preferably a curable resin material. The curable resin material is typically thermosetting and / or photocurable. The curable resin material may have both thermosetting and photocurable properties, or may have only one of thermosetting and photocurable properties. Specific examples of the curable resin material include epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials. As described in the first embodiment, the curable resin material may contain a filler having characteristic electric / magnetic properties.

[0078] (FIG. 3A2: Pressing of the support 30 against the membrane 2) FIG. 3A2 shows a state in which the surface having the convex portions of the support 30 having the convex portions is pressed against the membrane 2. A roller or other suitable means may be used to apply the appropriate pressure. Incidentally, when or immediately before pressing the support 30 against the film 2, it is preferable to heat the film 2 appropriately to soften the film 2. The heating temperature here is, for example, 40 to 80°C.

[0079] (Figure 3A3: Hardening of Membrane 2) When the film 2 is made of a curable resin material, the curable resin material can be hardened or semi-hardened to form the pattern layer 2B by applying an appropriate external stimulus (typically heat or light, preferably ultraviolet light) to the film 2. This can improve the adhesion between the base layer 1 and the pattern layer 2B. Furthermore, from the viewpoint of the aforementioned effect of the side surfaces of the recesses serving as "walls," it is preferable to harden or semi-harden the film 2. Specific methods and conditions for hardening can be the same as those in the first embodiment (see the explanation for FIG. 1A4). If the film 2 is to be hardened only semi-hardened, it is preferable to completely harden the pattern layer 2B by additional heating or light irradiation before performing the pressing (FIG. 4B4) described below.

[0080] (Figure 3A4: Separation) The laminate of base material layer 1 and pattern layer 2B obtained up to Fig. 3A3 is separated from support 30. This makes it possible to obtain a base material having recesses on its surface. The separation method is not particularly limited as long as damage to base material layer 1 and pattern layer 2B is suppressed. The thickness and cross-sectional shape of the substrate thus obtained, i.e., the laminate of the substrate layer 1 and the pattern layer 2B, can be the same as those in Embodiment 1. The cross-sectional shape of the pattern layer 2B shown in the drawing differs between Fig. 1A5, which has semicircular portions, and Fig. 3A4, which is mainly composed of straight lines, but it is similar in that it is preferable that the recesses are reverse-tapered in the direction away from the substrate.

[0081] (Figure 4B1: Fill in the blank) In Fig. 4B1, at least the recesses of the pattern layer 2B of the base material obtained in Fig. 3 are filled with a conductive composition containing conductive particles, thereby obtaining a hole-filling pattern 3B. The specific method of filling the holes, the fact that at least a portion of the excess conductive composition may be removed after filling the holes, and the fact that it is preferable that the conductive particles in the hole filling pattern 3B are not substantially sintered at this stage are the same as in the first embodiment. The specific aspects of the conductive composition are also the same as those in the first embodiment.

[0082] (Figure 4B2: Drying) If the conductive composition used in Fig. 4B1 contains a solvent, it is preferable to volatilize the solvent by heat treatment. The drying conditions are not particularly limited. The temperature and time may be set so as not to damage or deteriorate the substrate.

[0083] (Figure 4B3: Oxide film removal) In the second embodiment, too, it is preferable to infiltrate the filling pattern 3B with a component X capable of removing the oxide film on the surface of the conductive particles in the filling pattern 3B before or simultaneously with the pressing step described below. Specific matters regarding removal of the oxide film can be the same as those in the first embodiment.

[0084] (Figure 4B4: Press) At least pressure is applied to the filling pattern 3B of FIG. 4B2 or 4B3. This increases the conductivity of the filling pattern 3B, resulting in a conductive pattern 3C (FIG. 4B5). Preferably, the pressing causes at least a portion of the conductive particles in the filling pattern 3B to be sintered. In the pressing step, it is preferable to apply pressure to the filling pattern 3B while heating it. This tends to improve the conductivity of the resulting conductive pattern 3C. The specific method and conditions (pressure, temperature, etc.) of applying pressure and heating, the possibility of taking into consideration in advance the reduction in thickness of the filling pattern 3B due to drying of the solvent, the possibility of removing the oxide film and applying pressure simultaneously, the possibility of using member 9, and the specific form of member 9 may be the same as in the first embodiment.

[0085] (Figure 4B5) After the pressing is completed, if member 9 was used, it is removed. Then, a substrate with a conductive pattern can be obtained, which includes substrate layer 1 (substrate) having pattern layer 2B formed on one side thereof, and conductive pattern 3C formed by sintering conductive particles in the recesses of pattern layer 2B.

[0086] <Method for manufacturing a substrate provided with a conductive pattern: Third embodiment (FIGS. 5 and 6)> 5 and 6 are diagrams for explaining a method for manufacturing a substrate having a conductive pattern according to the third embodiment. One of the features of the method for manufacturing a substrate having a conductive pattern according to the third embodiment is that recesses are formed in the surface of the substrate by using an imprint process. Hereinafter, a method for manufacturing a substrate provided with a conductive pattern according to the third embodiment will be described with reference to FIGS.

[0087] (FIG. 5A1: Film formation on base layer 1) 5A1 shows that a film 2 made of a material for forming a pattern layer is formed on one surface of a base layer 1. The material for forming a pattern layer is usually a material different from that of the base layer 1. The material for forming the pattern layer is preferably a curable resin material. The curable resin material is typically thermosetting and / or photocurable. The curable resin material may have both thermosetting and photocurable properties, or may have only one of thermosetting or photocurable properties. Specific examples of the curable resin material include epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials. As described in the first embodiment, the curable resin material may contain a filler having characteristic electric / magnetic properties.

[0088] Considering the formation of recesses using a stamper, which will be described later, it is preferable that the curable resin material be a commercially available imprinting material, a commercially available OCA (Optically Clear Adhesive) film, an ultraviolet-curable hard coating agent, or the like.

[0089] (Figure 5A2: Semi-hardened) An external stimulus (usually heat or light) is applied to the film 2 formed in Fig. 5A1. At this time, it is preferable to semi-cure the film 2 without completely curing it. In other words, it is preferable to semi-cure the film 2 by appropriately adjusting the conditions for heating and light irradiation.

[0090] Here, the reason why it is preferable to semi-cure the film 2 rather than completely cure it is mainly to improve the adhesion of the conductive composition, and therefore the adhesion of the conductive pattern. From another perspective, if the base layer 1 and a stamper described later are non-light-transmitting, it may be preferable to semi-cure the film 2 in a previous stage, since photo-curing cannot be performed while the stamper is pressed against the film 2.

[0091] When semi-curing the film 2 by heating, the heating temperature and time are not particularly limited as long as the film 2 is semi-cured, but care should be taken to avoid heating at excessively high temperatures or for long periods of time, taking into account the heat resistance of the base layer 1. When semi-curing the film 2 with light (preferably ultraviolet light), the wavelength and irradiation amount of the light are not particularly limited as long as the film 2 is appropriately semi-cured. If the base layer 1 is light-transmitting, light may be irradiated through the base layer 1. Similarly, if the stamper 31 is light-transmitting, light may be irradiated through the stamper 31.

[0092] (Figure 5A3: Pressing the stamper) A stamper 31 is pressed against the film 2 in a semi-cured state in FIG. 5A2 (represented as semi-cured film 2B' in FIG. 5A3). This allows recesses to be formed in the semi-cured film 2B'. By pressing the stamper 31 against the semi-cured film rather than the uncured film, for example, it is possible to prevent pattern sagging and form the desired recesses with higher precision. Furthermore, peeling between the base layer 1 and the semi-cured film 2B' is more likely to be suppressed.

[0093] (Figure 6B1: Fill in the blank) In Fig. 6B1, at least the recesses of the semi-cured film 2B' on the substrate obtained in Fig. 5 are filled with a conductive composition 3 containing conductive particles, thereby obtaining a hole-filling pattern 3B.

[0094] FIG. 6B1 shows a screen printing method as a specific method for filling holes. That is, the holes are filled by selectively "printing" the conductive composition 3 into at least the recessed portions of the semi-cured film 2B' using a screen mesh 5 and a squeegee 41. While FIG. 6B1 shows a screen printing method, other printing methods can also be applied. For example, inkjet printing and dispense printing are also applicable. In the third embodiment, since the semi-cured film 2B′ is in a semi-cured state and is easily deformed, it is preferable to selectively fill the recesses with the conductive composition by a printing method rather than a method using a doctor blade 40 as shown in FIG. 2B1. Furthermore, by employing a printing method, it is possible to "selectively" fill the recesses with the conductive composition. Therefore, the printing method is also preferable from the viewpoint of saving / effectively utilizing the conductive composition. In this respect, it is also preferable to employ a printing method for filling the holes in other embodiments.

[0095] Similar to the first embodiment, at least a portion of the excess conductive composition may be removed after filling the holes, and the conductive particles in the recesses are preferably not substantially sintered at this stage. Specific aspects of the conductive composition are also similar to the first embodiment.

[0096] (Figure 6B2: Complete curing of semi-cured film) The semi-cured film 2B', which was in a semi-cured state until the hole filling shown in Figure 6B1, is completely cured by applying an appropriate external stimulus (usually light or heat), which causes the semi-cured film 2B' to become the patterned layer 2B (Figure 6B3). The method of applying an external stimulus (usually light or heat) to the semi-cured film 2B' is almost the same as that described in Fig. 5A2. As long as the semi-cured film 2B' is completely cured, the specific method of applying the external stimulus and the degree of the stimulus are not particularly limited.

[0097] (Figure 6B3: Drying) If the conductive composition used contains a solvent and, as a result, a non-negligible amount of solvent remains in the hole-filling pattern 3B, it is preferable to volatilize the solvent by heat treatment. The drying conditions are not particularly limited. The temperature and time may be set so as not to damage or deteriorate the substrate.

[0098] (Figure 6B4: Oxide film removal) In the third embodiment, too, it is preferable to infiltrate the filling pattern 3B with a component X capable of removing the oxide film on the surface of the conductive particles in the filling pattern 3B before or simultaneously with the pressing step described below. Specific matters regarding removal of the oxide film are the same as those in the first embodiment.

[0099] (Figure 6B5: Press) At least pressure is applied to the filling pattern 3B of FIG. 6B3 or 6B4. This increases the conductivity of the filling pattern 3B, resulting in a conductive pattern 3C (FIG. 6B6). Preferably, the pressure sinters at least a portion of the conductive particles in the filling pattern 3B. In the pressing step, it is preferable to apply pressure while heating the filling pattern 3B. This tends to improve the conductivity of the resulting conductive pattern 3C. The specific method and conditions (pressure, temperature, etc.) of applying pressure and heating, the fact that the reduction in thickness of the filling pattern 3B due to drying of the solvent may be taken into consideration in advance, the fact that oxide film removal and pressing can be performed simultaneously, the fact that member 9 may be used, and the specific form of member 9, etc., can be the same as in the first embodiment.

[0100] (Figure 6B6) After the pressing is completed, if member 9 was used, it is removed. Then, a substrate with a conductive pattern can be obtained, which includes substrate layer 1 (substrate) having pattern layer 2B formed on one side thereof, and conductive pattern 3C formed by sintering conductive particles in the recesses of pattern layer 2B.

[0101] <Method for manufacturing a substrate provided with a conductive pattern: Fourth embodiment (FIGS. 7 and 8)> 7 and 8 are diagrams for explaining a method for manufacturing a substrate having a conductive pattern according to the fourth embodiment. One of the features of the method for manufacturing a substrate having a conductive pattern according to the fourth embodiment is that a laser is used to provide a pattern layer 2B having recesses. Since the fourth embodiment does not require a support (intaglio plate) or a stamper, it can be said that the fourth embodiment is suitable for small-lot, high-mix production. Hereinafter, a method for manufacturing a substrate provided with a conductive pattern according to the fourth embodiment will be described with reference to FIGS.

[0102] (FIG. 7A1: Film formation on base layer 1) 7A1 shows that a film 2 made of a material for forming a pattern layer is formed on one surface of a base layer 1. The material for forming a pattern layer is usually a material different from that of the base layer 1. The material for forming the pattern layer is preferably a curable resin material. The curable resin material is typically thermosetting and / or photocurable. The curable resin material may have both thermosetting and photocurable properties, or may have only one of thermosetting or photocurable properties. Specific examples of the curable resin material include epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials. As described in the first embodiment, the curable resin material may contain a filler having characteristic electric / magnetic properties. To efficiently form recesses using a laser, which will be described later, it is possible to select a material for forming the pattern layer based on, for example, its laser light absorption. It is also possible to include a component (such as a dye) in the film 2 to enhance its laser light absorption.

[0103] (Figure 7A2: Hardening of Membrane 2) When film 2 is made of a curable resin material, the curable resin material can be cured or semi-cured by applying an appropriate external stimulus (typically heat or light, preferably ultraviolet light) to film 2. This can improve the adhesion between base layer 1 and film 2. Furthermore, by curing or semi-curing film 2, recesses can be formed with higher accuracy in the next step of forming recesses using a laser. When curing or semi-curing the curable resin material by heating, the heating temperature and time are not particularly limited as long as the curable resin material is properly cured or semi-cured. However, taking into account the heat resistance of the base layer 1, care should be taken to avoid excessively high temperatures or long heating times. When the curable resin material is cured or semi-cured with light (preferably ultraviolet light), the wavelength and irradiation amount of the light are not particularly limited as long as the curable resin material is appropriately cured or semi-cured. When the base layer 1 is light-transmitting, light may be irradiated through the base layer 1.

[0104] (Figure 7A3: Laser recess formation) As shown in FIG. 7A3, a film 2 (preferably a cured product of a curable resin material) is selectively irradiated with laser light to form a pattern layer 2B having recesses. There are no particular limitations on the type of laser as long as it is capable of forming recesses, but preferred examples of lasers that can be used include UV lasers, CO2 lasers, near-infrared lasers, and green lasers.

[0105] (Figure 8B1: Fill in the blank) In Fig. 8B1, at least the recesses of the pattern layer 2B of the base material obtained in Fig. 7 are filled with a conductive composition 3 containing conductive particles, thereby obtaining a hole-filled pattern 3B.

[0106] 8B1 shows a screen printing method as a specific method for filling the holes. That is, the holes are filled by selectively "printing" the conductive composition 3 into at least the recessed portions of the pattern layer 2B using a screen mesh 5 and a squeegee 41. While FIG. 8B1 shows a screen printing method, other printing methods can also be applied. For example, inkjet printing and dispense printing can also be applied.

[0107] Similar to the first embodiment, at least a portion of the excess conductive composition may be removed after filling the holes, and the conductive particles in the recesses are preferably not substantially sintered at this stage. Specific aspects of the conductive composition are also similar to the first embodiment.

[0108] (Figure 8B2: Drying) If the conductive composition used contains a solvent and, as a result, a non-negligible amount of solvent remains in the hole-filling pattern 3B, it is preferable to volatilize the solvent by heat treatment. The drying conditions are not particularly limited. The temperature and time may be set so as not to damage or deteriorate the substrate.

[0109] (Figure 8B3: Oxide film removal) In the fourth embodiment, too, it is preferable to infiltrate the filling pattern 3B with a component X capable of removing the oxide film on the surface of the conductive particles in the filling pattern 3B before or simultaneously with the pressing step described below. Specific matters regarding removal of the oxide film are the same as those in the first embodiment.

[0110] (Figure 8B4: Press) At least pressure is applied to the filling pattern 3B of FIG. 8B2 or 8B3. This increases the conductivity of the filling pattern 3B, resulting in a conductive pattern 3C (FIG. 8B5). Preferably, the pressing causes at least a portion of the conductive particles in the filling pattern 3B to be sintered. In the pressing step, it is preferable to apply pressure to the filling pattern 3B while heating it. This tends to improve the conductivity of the resulting conductive pattern 3C. The specific method and conditions (pressure, temperature, etc.) of applying pressure and heating, the fact that the reduction in thickness of the filling pattern 3B due to drying of the solvent may be taken into consideration in advance, the fact that oxide film removal and pressing can be performed simultaneously, the fact that member 9 may be used, and the specific form of member 9, etc., can be the same as in the first embodiment.

[0111] (Figure 8B5) After the pressing is completed, if member 9 was used, it is removed. Then, a substrate with a conductive pattern can be obtained, which includes substrate layer 1 (substrate) having pattern layer 2B formed on one side thereof, and conductive pattern 3C formed by sintering conductive particles in the recesses of pattern layer 2B.

[0112] <Method for manufacturing a substrate provided with a conductive pattern: Fifth embodiment (FIGS. 9 and 10)> 9 and 10 are diagrams for explaining the method for manufacturing a substrate having a conductive pattern according to the fifth embodiment. One of the features of the method for manufacturing a substrate having a conductive pattern according to the fifth embodiment is that a film made of a material for forming a pattern layer is not provided on the substrate layer, but recesses are formed on the surface of the substrate by directly irradiating the substrate layer with a laser. The fifth embodiment does not require a support (intaglio plate) or a stamper, so it can be said to be suitable for small-lot, high-mix production. In addition, since no material for forming the pattern layer is required, lower costs can be expected compared to the first embodiment, etc. Hereinafter, a method for manufacturing a substrate provided with a conductive pattern according to the fifth embodiment will be described with reference to FIGS.

[0113] (Figure 9A1: Preparation of substrate) First, a substrate layer 1 in which recesses are to be formed is prepared. Specific aspects of the substrate layer 1 are the same as those of the substrate layer 1 described in the first embodiment. The substrate layer 1 is typically a resin film. However, according to the findings of the present inventors, from the viewpoint of ease of forming recesses using a laser, the substrate layer 1 preferably contains polycarbonate. Alternatively, the substrate layer 1 preferably contains a foamed resin, specifically a foamed resin film or foamed resin sheet such as a foamed PET film.

[0114] (Figure 9A2: Formation of recesses using a laser) As shown in FIG. 9A2, by selectively irradiating the base layer 1 with laser light, a base material 1B having recesses can be obtained. There are no particular limitations on the type of laser as long as it is capable of forming recesses, but preferred examples of lasers that can be used include UV lasers, CO2 lasers, near-infrared lasers, and green lasers.

[0115] When recesses are formed using a laser, "waste" is usually generated from the base layer 1. Therefore, it is preferable to perform some kind of treatment to remove the waste. For example, the waste can be removed or reduced by attaching an adhesive tape to the base layer 1 and then peeling it off once or multiple times.

[0116] (Figures 10B1 to 10B5) 10B1 to 10B5 are the same as those shown in FIGS. 8B1 to 8B5, except that the substrate does not have a substrate layer 1 and a pattern layer 2B, but is a substrate 1B having recesses, and therefore detailed description thereof will be omitted.

[0117] <Method for manufacturing a substrate provided with a conductive pattern: Modification of the fifth embodiment> The method of directly forming recesses in the base layer without providing a film of the pattern layer-forming material on the base layer as in the fifth embodiment is not limited to the method using laser irradiation, and any method that can directly form recesses in a base material such as a resin film can be used as appropriate. One example is a method of forming recesses directly in a substrate layer using thermal imprinting. Specifically, a thermoplastic substrate such as a resin film is prepared, and the substrate is heated to soften it appropriately. A stamper (convex mold) is pressed against the substrate, and then the stamper is released, resulting in a substrate with recesses directly formed in the substrate. A conductive composition is then embedded in the recesses, as shown in FIG. 10, to produce a substrate with a conductive pattern.

[0118] <Substrate with conductive pattern> Up to this point, we have explained the "manufacturing method" for the substrate having a conductive pattern. Here, we will describe the physical characteristics of the substrate having a conductive pattern that is finally obtained.

[0119] By the method for manufacturing a substrate having a conductive pattern described in the present specification, it is possible to obtain the substrate as shown in Figures 2B5, 4B5, 6B6, 8B5 and 10B5. a substrate having a recessed portion on its surface; a conductive pattern formed by sintering conductive particles in the recess; A substrate provided with a conductive pattern, is manufactured.

[0120] The following includes much of what has already been explained in the first to fifth embodiments, but specific aspects of the substrate provided with the above-mentioned conductive pattern will be described in summary. The substrate preferably comprises at least a substrate layer and a pattern layer made of a material different from the substrate layer and provided on at least one side of the substrate layer, with recesses formed in the pattern layer. The thickness of the substrate layer is preferably 30 μm or more. The depth of the recesses in the pattern layer is preferably 3 to 100 μm. Furthermore, the pattern layer may contain a filler that changes the dielectric constant of the pattern layer or increases the electromagnetic wave absorption of the pattern layer. The pattern layer is preferably formed from a cured product of a curable resin material. The substrate is preferably flexible. From another perspective, the substrate preferably includes at least one selected from the group consisting of polyester, polyolefin, polycarbonate, polyimide, and paper. From yet another perspective, the substrate preferably includes a foamed resin. The particle diameter D at which the cumulative frequency reaches 50% in the volume-based cumulative particle diameter distribution curve obtained when the particle diameter of conductive particles is measured by the laser diffraction scattering method. 50 It is preferable that the thickness is 0.5 to 100 μm. It is preferable that the cross-sectional shape of the conductive pattern is inversely tapered in the direction away from the substrate (in the first embodiment, etc., it was explained that it is preferable that the recess in the pattern layer is inversely tapered in the direction away from the substrate. Therefore, the cross-sectional shape of the conductive pattern formed by being embedded in that recess will be inversely tapered in the direction away from the substrate).

[0121] <Electronic device manufacturing method> An electronic device can be manufactured using a substrate having a conductive pattern obtained as described above. By appropriately designing the hole-filling pattern, a substrate having a conductive pattern (circuit pattern) that can function as a circuit can be manufactured. Then, by combining this substrate with other electronic elements, an electronic device can be manufactured.

[0122] Here, some examples of electronic devices will be described, but it should be noted that the electronic devices including a substrate with a conductive pattern obtained by the manufacturing method described herein are not limited to these. Sensors: For example, a substrate having a conductive pattern obtained by the manufacturing method described herein can be applied to conductive members / circuits in sensors such as pressure sensors and vital sensors. Solar cells: For example, a substrate having a conductive pattern obtained by the manufacturing method described in this specification can be applied to the current collecting wiring of a solar cell. Membrane switch: A membrane switch is a thin sheet-like switch made by printing circuits and contacts on a film and then laminating it. The manufacturing method of a substrate with a conductive pattern described in this specification can be applied to form the circuits and contacts. Touch sensor / touch panel: For example, the method for manufacturing a substrate having a conductive pattern described herein can be applied to form lead wiring in a touch sensor / touch panel. It is also conceivable that the method for manufacturing a substrate having a conductive pattern described herein can be applied to form transparent electrodes in a touch sensor / touch panel. Flexible substrate: Conventionally, circuits are formed by first coating the entire surface of a flexible film with a metal film and then using chemicals to remove unnecessary parts of the metal film. Instead of this conventional method, it is conceivable to form circuits using the method for manufacturing a substrate with a conductive pattern described in this specification.

[0123] In particular, in electronic devices where circuits have conventionally been formed using conductive paste, by using the manufacturing method described in this specification as a method for forming circuits, the resistivity of the circuits can be reduced, and improved performance of the electronic devices can be expected.

[0124] A particularly preferred example of the electronic device is an RF tag. That is, the method for producing a conductive substrate of this embodiment is preferably used to produce a conductive circuit such as an antenna portion of an RF tag. For the specific structure of the RF tag, reference can be made to, for example, Japanese Patent Application Laid-Open No. 2003-332714 and Japanese Patent Application Laid-Open No. 2020-46834.

[0125] <Method of manufacturing electromagnetic wave shielding film> As an application other than electronic devices, the method for manufacturing a substrate having a conductive pattern according to the present embodiment can be used to manufacture an electromagnetic wave shielding film. Specifically, in the lamination step, the conductive composition is printed in a pattern specific to the electromagnetic wave shielding film (such as a mesh pattern), thereby manufacturing the electromagnetic wave shielding film.

[0126] <Method of manufacturing a sheet heating element> As another application, the method for manufacturing a substrate having a conductive pattern according to this embodiment may be used to manufacture a sheet heating element. A sheet heating element is an element that generates heat by passing an electric current through electrical wiring provided on a substrate. A specific example of a sheet heating element is a sheet heating element for preventing fogging or cold weather, such as on the rear window of a passenger car.

[0127] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0128] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. However, it should be noted that the present invention is not limited to the Examples.

[0129] Example 1 (Preparation of Support 1 (Intaglio)) A plate manufacturer was commissioned to prepare a support 1 (intaglio plate) on a copper plate by laser engraving, where a pattern structure with lines (protruding portions) / spaces (recesses) = 90 μm / 110 μm and recesses 40 μm deep was formed on the copper plate, and the surface was chrome-plated. The cross-sectional shape of the recesses in support 1 was approximately arc-shaped.

[0130] (Preparation of Conductive Composition 1) First, 48 parts by mass of polyvinylpyrrolidone and 52 parts by mass of an organic solvent were weighed into a glass bottle, which was then placed in a hot air circulating atmospheric oven and heated at 100° C. for 2 hours, thereby obtaining a solution in which polyvinylpyrrolidone was completely dissolved. After that, copper powder (D 50 75 parts by mass of copper powder (=5 μm), 6 parts by mass of the above solution, and 19 parts by mass of organic solvent were weighed, kneaded with a spatula, and further stirred with a planetary centrifugal mixer. In this way, conductive composition 1 was obtained. In this conductive composition 1, the ratio of resin to copper powder was 3.8% by mass.

[0131] (Production of a substrate with a conductive pattern) A substrate provided with a conductive pattern was manufactured as shown in Figures 1 and 2. Details will be explained below.

[0132] First, a hard coating agent NSX-101T (a UV-curable resin material containing an acrylic monomer, a photopolymerization initiator, a urethane acrylate oligomer, etc.) manufactured by Kyoeisha Chemical Co., Ltd., which is a material for forming a pattern layer, was applied to a support 1 to a wet thickness of 50 μm to form a film. This film was then attached to a PET film (a highly adhesive polyester film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd., thickness 50 μm).

[0133] After lamination, ultraviolet light was irradiated from the PET film side. A UV-LED lamp manufactured by Matsuo Sangyo Co., Ltd. was used as the light source. The specific irradiation conditions were a cumulative light dose of 1500 mJ / cm in the UVA (320-390 nm) range. 2 The PET film was then irradiated four times with the light irradiating agent at 1000 W. This allowed the curing reaction to proceed substantially completely. The PET film was then peeled off from the support 1. The PET film was then used as the base material for filling holes, i.e., the PET film on which the pattern layer having recesses formed thereon was formed using the pattern layer-forming material.

[0134] Thereafter, conductive composition 1 was placed on the pattern of the hole-filling substrate. Then, a doctor blade was used to fill only the recesses with conductive composition 1, and excess conductive composition 1 was removed. Next, the substrate was heated at 100°C for 15 minutes using a hot air circulating atmospheric oven to volatilize the organic solvent contained in the conductive composition 1 in the recesses. In this way, a hole-filling pattern was obtained.

[0135] After that, the oxide film was removed and pressure and heat were applied by a roll press. Specifically, first, an oxide film removing solution (formic acid solution) was sprayed onto the hole filling pattern. The spray amount was approximately 600 mm 2 The amount of solution was approximately 20 μL for an area of ​​this size. Then, a silicone-treated, easily peelable PET film (a silicone PET film, corresponding to member 9 in FIG. 2B4) was placed on top of the hole-filling pattern, and processing was carried out under the following conditions. After processing was completed, the silicone PET film was peeled off. A substrate with a conductive pattern was thus obtained. Roll temperature: 110℃ Pressure: 40 MPa Conveying speed: 0.1 m / min Roll gap: The total thickness of the processed item minus 20 to 30 μm

[0136] [remarks] Roll temperature The roll press machine was equipped with a non-contact temperature sensor, but in order to measure the temperature more accurately, a contact thermometer was attached to the roll to measure the temperature. Pressure: Calculated using the following method. Roll width: 165 mm, contact width between rolls: 3 mm, pressure area: 495 mm 2 The pressure was 20kN. 495mm 2 Since a force of 20kN was applied to the area, 20kN ÷ 495mm 2 Based on the calculation, the pressure was calculated to be 40 MPa.

[0137] <Example 2> (Preparation of Support 2 (Intaglio)) A plate manufacturer was commissioned to prepare a support (intaglio plate) made of nickel by electroforming, on which a pattern structure with lines (protrusions) / spaces (recesses) = 40 μm / 60 μm and recesses 30 μm deep was formed. This support (intaglio plate) is referred to as support 2. The cross-sectional shape of the recesses in support 2 was approximately rectangular, and the recesses were reverse-tapered from the bottom of the recesses in the direction away from support 2, with an angle of approximately 2°.

[0138] (Preparation of Conductive Composition 2) First, 20.5 parts by mass of commercially available organic solvent-soluble polyester resin and 79.5 parts by mass of organic solvent were weighed into a glass bottle and heated at 120°C for 3 hours using a hot air circulating atmospheric oven, thereby obtaining a resin solution in which the polyester resin was completely dissolved. Next, copper powder (D 50 72 parts by mass of copper powder (=5 μm) and 28 parts by mass of the resin solution were weighed, kneaded with a spatula, and further stirred with a planetary centrifugal mixer. In this way, conductive composition 2 was obtained. In this conductive composition 2, the ratio of resin to copper powder was 7.5% by mass.

[0139] (Production of a substrate with a conductive pattern) A substrate provided with a conductive pattern was manufactured as shown in Figures 3 and 4. Details will be explained below.

[0140] First, using an applicator preheated to 60°C, a pattern layer forming material preheated to 60°C, specifically a UV-curable resin (containing urethane acrylate polymer, acrylic monomer, photopolymerization initiator, etc.) from Sanyo Chemical Industries, Ltd., was applied to the surface of a PET film (a 50 μm thick, highly adhesive polyester film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd.) to a wet thickness of 40 μm to form a film. (The applicator and the material for forming the pattern layer were preheated in order to ensure good coating properties and to allow the material to be pressed against the support 2 in the next step.)

[0141] The film formed on the PET film was pressed against a support 2 preheated to 60°C, and ultraviolet light was irradiated from the PET film side. A UV-LED lamp manufactured by Matsuo Sangyo Co., Ltd. was used as the light source. Specific irradiation conditions were an integrated light dose of 6000 mJ / cm2 in the UVA (320-390 nm) range. 2 The PET film was then irradiated with light of 1000 W at 1000 W. This allowed the curing reaction to proceed substantially completely. The PET film was then peeled off from the support 2 ...

[0142] Thereafter, filling of the holes with the conductive composition, removal of the oxide film, and application of pressure and heat by a roll press were carried out in the same manner as in Example 1, except that conductive composition 2 was used as the conductive composition instead of conductive composition 1. Then, a substrate provided with a conductive pattern was obtained.

[0143] <Evaluation> The conductive pattern portion of the substrate provided with the conductive pattern produced in Example 1 was observed under a microscope. As a result of the observation, it was confirmed that the conductive pattern was formed in the recesses almost as intended, as shown in Figure 11. In other words, it was confirmed that deformation of the pattern was suppressed even when pressure was applied.

[0144] The conductive pattern portion of the substrate provided with the conductive pattern produced in Example 2 was also observed under a microscope. As a result of the observation, it was confirmed that the conductive pattern was formed in the recesses almost as intended, as shown in Figure 12. In other words, it was confirmed that deformation of the pattern was suppressed even when pressure was applied.

[0145] Through the process of "filling recesses with a conductive compound" and "pressing," it was possible to create thin conductive patterns (circuit patterns) with a line width of less than 100 μm with high precision.

[0146] Example 3 9 and 10, a substrate having a conductive pattern was produced by forming recesses directly in a resin film by laser irradiation, filling the recesses with a conductive composition, and then pressing the film. Details are explained below.

[0147] First, a commercially available 100 μm thick polycarbonate film was irradiated with laser light using a Keyence 3-Axis UV laser marker under the following conditions: output power 80%, scan speed 500 mm / s, and two scans. Any generated debris was removed as much as possible using adhesive tape. In this way, a recess approximately 30 μm deep and 170 μm wide was formed in the polycarbonate film.

[0148] The recesses formed above were filled with the conductive composition of Example 2 (conductive composition 2) using a squeegee, and the excess conductive composition was scraped off. Thereafter, the solvent in the conductive composition filling the recesses was dried. In this way, a hole-filled pattern was obtained. An oxide film remover (formic acid solution) was sprayed onto the hole-filling pattern, and a silicone-treated, easily peelable PET film (silicone PET film) was placed on top of it. Then, using a flat press, pressure and heat were applied at 110°C, 67 MPa, and 60 seconds. In this way, a substrate with a conductive pattern was obtained.

[0149] An electron microscope image of the cross section of the resulting substrate with the conductive pattern is shown in Figure 13. Note that Figure 13 also shows the embedding resin layer used for cross section processing. FIG. 13 shows that a substrate having a conductive pattern can also be manufactured by a method of directly forming recesses in a resin film with a laser. [Explanation of symbols]

[0150] 1 Base material layer 1B Base material 2 membrane 2B' Semi-hardened layer 2B pattern layer 3 Conductive composition 3B Filling Pattern 3C Conductive Pattern 7. Liquid (liquid containing component X capable of removing oxide film on the surface of conductive particles) 9. Member (preferably film-like material) 10A roll 10B roll 30 Support (typically intaglio) 31 Stamper 40 Doctor Blade 41 Squeegee

Claims

1. a hole filling step of filling recesses provided on the surface of the substrate with a conductive composition containing conductive particles to obtain a hole-filled pattern; a pressing step of applying at least pressure to the hole filling pattern to obtain a conductive pattern; A method for manufacturing a substrate having a conductive pattern, comprising:

2. A method for manufacturing a substrate provided with the conductive pattern according to claim 1, comprising: A method for manufacturing a substrate having a conductive pattern, comprising a removing step of removing at least a portion of the excess conductive composition that was not filled in the recesses in the filling step after the filling step and before the pressing step.

3. A method for manufacturing a substrate provided with the conductive pattern according to claim 2, comprising: The method for manufacturing a substrate provided with a conductive pattern, wherein the removing step is carried out by scraping off the excess conductive composition.

4. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: In the hole filling step, the recesses are filled with the conductive composition by a printing method.

5. A method for manufacturing a substrate provided with the conductive pattern according to claim 4, comprising: The method for producing a substrate provided with a conductive pattern, wherein the printing method is a screen printing method, an inkjet printing method or a dispenser printing method.

6. A method for manufacturing a substrate provided with the conductive pattern according to claim 1 or 2, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the substrate comprises at least a substrate layer and a pattern layer made of a material different from the substrate layer and provided on at least one side of the substrate layer, and a recess is formed in the pattern layer.

7. A method for manufacturing a substrate provided with the conductive pattern according to claim 6, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed from a curable resin material.

8. A method for manufacturing a substrate provided with the conductive pattern according to claim 7, comprising: In the hole filling step, the curable resin material forming the pattern layer is in an uncured or semi-cured state.

9. A method for manufacturing a substrate provided with the conductive pattern according to claim 7, comprising: A method for manufacturing a substrate provided with a conductive pattern, comprising, before the pressing step, a curing step of curing the curable resin material forming the pattern layer.

10. A method for manufacturing a substrate provided with the conductive pattern according to claim 7, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by forming a film made of a curable resin material on the surface of a support having convex portions and attaching the film to the substrate layer.

11. A method for manufacturing a substrate provided with the conductive pattern according to claim 7, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by pressing a stamper against a film formed on at least one side of the substrate layer using the curable resin material.

12. A method for manufacturing a substrate provided with the conductive pattern according to claim 7, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer is formed by irradiating a film formed on at least one side of the substrate layer using the curable resin material with laser light.

13. A method for manufacturing a substrate provided with the conductive pattern according to claim 6, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the thickness of the substrate layer is 30 μm or more.

14. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses directly formed thereon.

15. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses formed directly on the resin film by irradiating the resin film with laser light.

16. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the substrate is a resin film having recesses formed directly thereon by a thermal imprinting method.

17. A method for manufacturing a substrate provided with the conductive pattern according to claim 14, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the substrate has a thickness of 30 μm or more.

18. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: a step of removing an oxide film, after the filling step and before or simultaneously with the pressing step, of penetrating a component X capable of removing an oxide film on the surface of the conductive particles into the filling pattern.

19. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: In the pressing step, the hole filling pattern is pressed while being heated.

20. A method for manufacturing a substrate provided with the conductive pattern according to claim 19, comprising: In the pressing step, the hole-filling pattern is pressed with a pressure of 1 to 500 MPa and heated at a temperature of 80 to 400°C.

21. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the conductive composition is in a paste state at room temperature.

22. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the amount of the resin component in the conductive composition is 15 parts by mass or less per 100 parts by mass of the conductive particles.

23. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: A method for producing a substrate having a conductive pattern, wherein the conductive composition does not substantially contain a curable component as a component other than the conductive particles.

24. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The particle diameter D at which the cumulative frequency reaches 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method. ５０ A method for manufacturing a substrate having a conductive pattern, wherein the thickness is 0.5 to 100 μm.

25. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: In the pressing step, the exposed surface of the filling pattern is covered with a member, and then the filling pattern is at least pressed.

26. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the cross-sectional shape of the recess is reverse tapered in a direction away from the substrate.

27. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate provided with a conductive pattern, wherein the recess has a depth of 3 to 100 μm.

28. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: The method for manufacturing a substrate having a conductive pattern, wherein the substrate is flexible.

29. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the substrate includes at least one selected from the group consisting of polyester, polyolefin, polycarbonate, polyimide, and paper.

30. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the substrate contains a foamed resin.

31. A method for manufacturing a substrate provided with the conductive pattern according to any one of claims 1 to 3, comprising: A method for manufacturing a substrate having a conductive pattern, wherein the pattern layer contains a filler that changes the dielectric constant of the pattern layer or increases the electromagnetic wave absorption properties of the pattern layer.

32. A method for producing an electronic device, comprising producing an electronic device using a substrate having a conductive pattern obtained by the method for producing a substrate having a conductive pattern according to any one of claims 1 to 3.

33. 33. The method of claim 32, further comprising the steps of: The method for manufacturing an electronic device, wherein the electronic device is an RF tag.

34. A method for producing an electromagnetic wave shielding film, comprising producing an electromagnetic wave shielding film using a substrate having a conductive pattern obtained by the method for producing a substrate having a conductive pattern according to any one of claims 1 to 3.

35. A method for manufacturing a sheet heating element, comprising manufacturing a sheet heating element using a substrate having a conductive pattern obtained by the method for manufacturing a substrate having a conductive pattern according to any one of claims 1 to 3.

36. a substrate having a recessed portion on its surface; a conductive pattern formed by sintering conductive particles in the recess; A substrate provided with a conductive pattern.

37. A substrate provided with the conductive pattern according to claim 36, The substrate is a substrate with a conductive pattern, which comprises at least a substrate layer and a pattern layer made of a material different from the substrate layer and provided on at least one side of the substrate layer, and in which a recess is formed in the pattern layer.

38. A substrate provided with the conductive pattern according to claim 37, A substrate provided with a conductive pattern, wherein the pattern layer is formed from a cured product of a curable resin material.

39. A substrate provided with the conductive pattern according to claim 37 or 38, A substrate provided with a conductive pattern, wherein the thickness of the substrate layer is 30 μm or more.

40. A substrate provided with the conductive pattern according to claim 36 or 37, The particle diameter D at which the cumulative frequency reaches 50% in a volume-based cumulative particle diameter distribution curve obtained when the particle diameter of the conductive particles is measured by a laser diffraction scattering method. ５０ A substrate provided with a conductive pattern, wherein the thickness is 0.5 to 100 μm.

41. A substrate provided with the conductive pattern according to claim 36 or 37, A substrate provided with a conductive pattern, wherein the cross-sectional shape of the conductive pattern is reverse tapered in a direction away from the substrate.

42. A substrate provided with the conductive pattern according to claim 36 or 37, A substrate provided with a conductive pattern, wherein the depth of the recesses in the pattern layer is 3 to 100 μm.

43. A substrate provided with the conductive pattern according to claim 36 or 37, The substrate is flexible and has a conductive pattern.

44. A substrate provided with the conductive pattern according to claim 36 or 37, The substrate is provided with a conductive pattern and includes at least one selected from the group consisting of polyester, polyolefin, polycarbonate, polyimide, and paper.

45. A substrate provided with the conductive pattern according to claim 36 or 37, The substrate includes a foamed resin and is provided with a conductive pattern.

46. A substrate provided with the conductive pattern according to claim 36 or 37, A substrate provided with a conductive pattern, wherein the pattern layer contains a filler that changes the dielectric constant of the pattern layer or increases the electromagnetic wave absorption property of the pattern layer.

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