JP6885413B2 - Manufacturing method of conductive pattern substrate - Google Patents

Description

The present invention relates to a method for manufacturing a conductive pattern substrate capable of easily forming a high-definition conductive pattern.

As a method for manufacturing a conductive pattern substrate in which a patterned conductive layer is formed on a base material, for example, a method of forming a conductive layer on the base material and then forming the conductive layer into a pattern by a photolithography method is known. ing.

Further, as another method for manufacturing a conductive pattern substrate, a method of preparing a base material having a groove formed therein and filling the groove portion with a conductive paste is known.
For example, Patent Documents 1 to 5 describe a method of manufacturing a conductive pattern substrate by preparing a conductive paste containing a powder of a conductive material and a binder such as a thermoplastic resin and filling the groove with the conductive paste. Has been done. Further, as a method of filling the conductive paste, a method of filling the conductive paste only in the groove portion by using an inkjet method or the like, a method of applying the conductive paste to the entire surface of the base material, and then using a squeegee or various polishing devices. A method of scraping off the conductive paste on the flat surface portion is described.
Further, Patent Document 6 describes a method in which a release layer is formed on a flat surface portion, a conductive paste is applied to the entire surface of the base material, and the conductive paste on the flat surface portion is removed together with the release layer.
According to such a method, it is possible to obtain a conductive pattern substrate in which a patterned conductive layer is embedded in a groove of a base material.

Japanese Unexamined Patent Publication No. 10-93234 Japanese Unexamined Patent Publication No. 2003-204140 Japanese Unexamined Patent Publication No. 2003-264361 Japanese Unexamined Patent Publication No. 2004-152934 Japanese Unexamined Patent Publication No. 2006-24672 Japanese Unexamined Patent Publication No. 8-148805

However, in the method of filling the conductive paste only in the groove portion such as the inkjet method, it is difficult to fill the conductive paste only in the groove portion when the width of the groove portion in which the conductive paste is filled is narrow.
Further, in the method of scraping off the conductive paste on the flat surface portion, there is a possibility that the shape of the groove portion is deformed when the squeegee comes into contact with the groove portion, and that the conductive paste is left uncut, resulting in a short circuit or the like. There is a problem such as there is.
Further, the method of forming the release layer has a problem that the manufacturing process of the conductive pattern substrate becomes complicated due to the formation of the release layer.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a method for manufacturing a conductive pattern substrate capable of easily forming a high-definition conductive pattern.

As a result of repeated research to solve the above problems, the present inventors have formed a coating film on the entire surface of the base material including the groove for wiring by using a nanoparticle dispersion liquid in which nanoparticles are dispersed in a dispersion medium. , The coating film is broken at the boundary between the wiring groove and the surface of the base material other than the wiring groove of the base material (hereinafter, may be simply referred to as the boundary of the wiring groove), and further, the coating film By sintering the contained nanoparticles into a porous layer, the adhesion to the base material is reduced and the strength of the nanoparticles in the plane direction is improved, so that the nanoparticles can be easily peeled off from the base material. We found that and came to complete the present invention.

That is, in the present invention, a base material having a wiring groove portion, which is a groove portion on which wiring is formed, is prepared on one surface, and metal nanoparticles and a dispersion medium are formed on the surface of the base material on which the wiring groove portion is formed. A coating step of applying a nanoparticle dispersion liquid containing the above, a drying step of drying the nanoparticle dispersion liquid coated on the base material to form a coating film containing the metal nanoparticles, and a drying step included in the coating film. A sintering step of sintering the metal nanoparticles to form a porous conductive layer and a peeling step of peeling off the porous conductive layer formed on the surface of the base material other than the groove for wiring. Provided is a method for manufacturing a conductive pattern substrate, which is characterized by having.

According to the present invention, by using the nanoparticle dispersion liquid, the coating film formed by the drying step can be made to be broken at the boundary of the wiring groove portion. Therefore, it is possible to form a porous conductive layer that is broken at the boundary of the wiring groove portion by the above sintering step.
Therefore, in the peeling step, only the porous conductive layer formed on the surface of the base material (hereinafter, may be simply referred to as a flat surface portion) other than the wiring groove portion can be easily peeled off.
Further, by forming a porous conductive layer in which metal nanoparticles are sintered by the above sintering step, a porous conductive layer having low adhesion to a base material and excellent strength in the plane direction is formed on a flat surface portion. Can be formed. Therefore, the porous conductive layer formed on the flat surface can be easily peeled off in the peeling step.
Therefore, a high-definition conductive pattern can be easily formed.

In the present invention, the metal nanoparticles are preferably silver nanoparticles or copper nanoparticles. This is because a conductive pattern substrate having excellent conductivity and cost can be obtained.

In the present invention, it is preferable that the sintering step is to sinter the metal nanoparticles by firing the coating film by surface wave plasma treatment. This is because a porous conductive layer having excellent adhesion to the base material can be formed in the groove for wiring.

In the present invention, in the peeling step, the peeling base material having adhesiveness or adhesiveness is brought into contact with only the porous conductive layer formed on the surface of the base material other than the wiring groove portion, and then the peeling is performed. It is preferable that the porous conductive layer is peeled off together with the base material. This is because the porous conductive layer can be easily peeled off.

The present invention has the effect of providing a method for manufacturing a conductive pattern substrate capable of easily forming a high-definition conductive pattern substrate.

It is a process drawing which shows an example of the manufacturing method of the conductive pattern substrate of this invention. It is schematic cross-sectional view explaining the coating film in this invention. It is an optical microscope observation result of the conductive substrate and the conductive pattern substrate produced in Example 1. It is the SEM observation result around the wiring groove part of the conductive pattern substrate produced in Example 1.

The present invention relates to a method for manufacturing a conductive pattern substrate.
Hereinafter, the method for manufacturing the conductive pattern substrate of the present invention will be described in detail.

In the method for manufacturing a conductive pattern substrate of the present invention, a base material having a wiring groove portion, which is a groove portion on which wiring is formed, is prepared on one surface, and a metal is formed on the surface of the base material on which the wiring groove portion is formed. A coating step of applying a nanoparticle dispersion liquid containing nanoparticles and a dispersion medium, and a drying step of drying the nanoparticle dispersion liquid coated on the base material to form a coating film containing the metal nanoparticles. The sintering step of sintering the metal nanoparticles contained in the coating film to form a porous conductive layer, and peeling off the porous conductive layer formed on the surface of the base material other than the groove for wiring. It is a manufacturing method characterized by having a peeling step.

The method for manufacturing the conductive pattern substrate of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for manufacturing a conductive pattern substrate of the present invention. As illustrated in FIG. 1, in the method for manufacturing a conductive pattern substrate of the present invention, a base material 1 having a wiring groove portion 1a, which is a groove portion on which wiring is formed, is prepared on one surface, and the above-mentioned base material 1 is described above. A nanoparticle dispersion liquid 2 containing metal nanoparticles and a dispersion medium is applied to the surface on which the wiring groove 1a is formed (FIG. 1A).
Next, hot air h is blown onto the nanoparticle dispersion liquid 2 coated on the base material 1 to dry the dispersion medium in the nanoparticle dispersion liquid 2 to form a coating film containing the metal nanoparticles (Fig.). 1 (b)).
Next, the coating film 3 is subjected to surface wave plasma treatment p in a hydrogen gas atmosphere to sinter the metal nanoparticles contained in the coating film 3 to form a porous conductive layer (). FIG. 1 (c).
Next, the peeling base material 5 is brought into contact with only the porous conductive layer 4 formed on the flat surface portion 1b, which is the surface of the base material other than the wiring groove portion 1a, among the porous conductive layer 4 (FIG. 1 (d)) By peeling the porous conductive layer 4 together with the peeling base material 5, the porous conductive layer 4 formed on the flat surface portion 1b is peeled off, and only the wiring groove portion 1a is porous. A conductive pattern substrate 10 on which the conductive layer 4 is formed is obtained (FIG. 1 (e)).
Note that FIG. 1 (a) is a coating step, FIG. 1 (b) is a drying step, FIG. 1 (c) is a sintering step, and FIGS. 1 (d) to 1 (e) are peeling steps. ..
Further, in this example, in the peeling step, an adhesive tape having a supporting base material 5a and an adhesive layer 5b formed on the supporting base material 5a is used as the peeling base material 5.

According to the present invention, by using the nanoparticle dispersion liquid, the coating film formed by the drying step can be made to be broken at the boundary of the wiring groove portion. Therefore, it is possible to form a porous conductive layer that is broken at the boundary of the wiring groove portion by the above sintering step.
Therefore, in the peeling step, only the porous conductive layer formed on the flat surface can be easily peeled off.
Further, by forming a porous conductive layer in which metal nanoparticles are sintered by the above sintering step, a porous conductive layer having low adhesion to a base material and excellent strength in the plane direction is formed on a flat surface portion. Can be formed. Therefore, the porous conductive layer formed on the flat surface can be easily peeled off in the peeling step.
Therefore, a high-definition conductive pattern can be easily formed.

The reason why the coating film formed by the drying step can be broken at the boundary of the wiring groove portion by using the nanoparticle dispersion liquid is presumed as follows.
That is, in a general conductive paste in which conductive fine particles are used together with an organic or inorganic binder, the proportion of the binder is relatively large, and the conductive layer finally used as wiring also has a form in which the conductive fine particles are dispersed in the binder. Become. Such a conductive layer has a strong bond in the plane direction due to the presence of a binder, and also has a large adhesion to the base material.
On the other hand, a binder resin or the like is added to the nanoparticle dispersion liquid used for forming the porous conductive layer by sintering the metal nanoparticles from the viewpoint of dispersion stability in the dispersion medium of the metal nanoparticles. Sometimes. However, since such a binder resin or the like is decomposed and removed at the time of sintering, the amount of the binder resin added is small. Therefore, the coating film formed by applying the nanoparticle dispersion liquid and then drying has a lower bonding force in the plane direction than the coating film formed by a general conductive paste, and a groove for wiring is formed. The coating film is easily broken at the place where there is a step as described above.
Therefore, it is possible to form a coating film that is broken at the boundary of the wiring groove portion by the drying step.

Further, the reason why the adhesion of the coating film to the substrate is lowered by the sintering process is presumed as follows.
That is, the coating film formed by the drying step contains a binder resin or the like in a small amount. On the other hand, after the sintering step, the binder resin and the like are in a state of being decomposed and removed.
Therefore, the porous conductive layer has a lower content of the binder resin and the like as compared with the coating film, and has a low adhesion to the base material.
For this reason, the coating film is made into a porous conductive layer by the sintering process, so that the adhesion with the base material is reduced.

The method for producing a conductive pattern substrate of the present invention includes the above-mentioned coating step, drying step, sintering step, and peeling step.
Hereinafter, each step of the method for manufacturing the conductive pattern substrate of the present invention will be described in detail.

1. 1. Coating step In the coating process in the present invention, a base material having a wiring groove portion, which is a groove portion on which wiring is formed, is prepared on one surface, and metal nanoparticles are formed on the surface of the base material on which the wiring groove portion is formed. This is a step of applying a nanoparticle dispersion liquid containing a dispersion medium.

(1) Base material The base material used in this step has a wiring groove, which is a groove on which wiring is formed, on one surface.

The base material may be a transparent base material or a non-transparent base material, but is preferably a transparent base material. This is because the conductive pattern substrate can be suitably used for applications requiring transparency, for example, a display device with a touch panel.
The transmittance of the base material in the visible light region is preferably 80% or more, and more preferably 85% or more. Here, the transmittance of the base material can be measured by JIS K7361-1 (a test method for the total light transmittance of a plastic-transparent material).
The transmittance of the base material refers to the transmittance at the place where the flat surface portion of the base material is formed.

The base material may have a single-layer structure including only one layer or a multi-layer structure including two or more layers.
For example, the base material has a single-layer structure containing only one support base material, a multi-layer structure in which two or more support base materials are laminated, a support base material, and a wiring groove formed on the support base material and the support base material. It can be a multi-layer structure or the like having a surface layer.
In the present invention, when the method for forming the base material is the imprint method, it is preferable that the base material has a support base material and a surface layer formed on the support base material. This is because it is easy to form a groove for wiring.
The imprint method referred to here is a method of embossing, engraving, or molding unevenness.

The supporting base material constituting the supporting base material is not particularly limited as long as it has insulating properties and can form a wiring groove portion having a desired shape, and an inorganic material and a resin material are used. be able to.
Examples of the inorganic material include glass (for example, soda lime glass, non-alkali glass, borosilicate glass, quartz glass, etc.), alumina, and the like.
As the resin material, a general resin material can be used. Suitable specific examples of the resin material include polyimide, polyamide, polyamideimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide, polyetheretherketone, polyethersulfone, polycarbonate, polyetherimide, and epoxy resin. , Phenolic resin, glass-epoxy resin, polyphenylene ether, acrylic resin, polyolefin such as polyethylene and polypropylene, polycycloolefin such as polynorbornene, liquid crystal polymer compound and the like.
In the present invention, it is possible to use a thermoplastic resin as the resin material, that is, when the supporting base material is a thermoplastic resin base material, the pattern can be directly transferred by the thermal imprint method described later.

The surface layer material constituting the surface layer is not particularly limited as long as it can accurately form the wiring groove, but the imprint method is used to form the wiring groove on the surface layer. In the case of the above, for example, a curable material such as a thermoplastic resin, a curable resin, an inorganic curable material, an organic-inorganic hybrid curable material in which an organic structure is combined with an inorganic structure, and a combination thereof are used. Can be used.

When a thermoplastic resin is used as the surface layer material, as the imprint method, for example, the template is pressed while the thermoplastic resin is heated to the glass transition temperature or higher to transfer the pattern. The method can be used.
Examples of the thermoplastic resin include acrylic resin, polyester resin, polycarbonate resin, cycloolefin resin, polypropylene resin, polyethylene resin, amide resin, polyvinyl chloride resin, polyamide resin, polyurethane resin, acetal resin, and phenoxy resin. Resin is mentioned.

When a curable material is used as the surface layer material, as the imprint method, for example, a liquid or thermoplastic curable material is cured while being pressed by a template, and then the template is removed to obtain a pattern. An imprint method for transfer can be used.
Examples of the curable resin include thermosetting resins and photocurable resins.
Examples of the thermosetting resin include phenol resins, epoxy resins, melamine resins and the like.
Examples of the photocurable resin include a radical polymerization type resin using a photoradical curing reaction and a cationic polymerization type resin using a photocationic curing reaction.
Examples of the radical polymerization type resin include compounds having an ethylenically unsaturated double bond such as an acryloyl group, a metaacryloyl group, a vinyl group, and an allyl group, an oligomer, and a polymer.
Examples of the cationically polymerizable resin include compounds having a photocationically polymerizable group such as a vinyl group, an epoxy group, and an oxetanyl group, an oligomer, and a polymer.
When a photocurable resin is used, only one type may be used or two or more types may be used in combination. As the photocurable resin, for example, a radical polymerization type resin and a cationic polymerization type resin may be used in combination.
Examples of the inorganic curable material include materials obtained by curing precursors such as metal alkoxide, metal acetylacetonate, and metal carboxylate by polycondensation by hydrolysis, and examples of the metal include Si, Ti, and Al. , Zn and the like.
Examples of the organic-inorganic hybrid curable material in which the above-mentioned inorganic structure is combined with an organic structure include a material in which a photocurable organic functional group such as an ethylenically unsaturated double bond is bonded to an inorganic skeleton such as polysiloxane. Examples thereof include cissesquioxane copolymers.
When the above-mentioned photocurable resin is used, it is preferable to use a transparent one as the support base material because it can be cured by irradiating light through the support base material.

The thickness of the base material is not particularly limited as long as it can stably form the groove for wiring, but it can be in the range of 1.0 μm to 1000 μm. When the thickness of the base material is within the above range, deformation of the base material is suppressed when the porous conductive layer is formed, which is preferable in terms of shape stability of the formed porous conductive layer, and winding. It is suitable in terms of flexibility when the cutting process is continuously performed.
The thickness refers to the total thickness of all the layers constituting the base material when the layer structure of the base material is a multi-layer structure.

The width of the groove for wiring is not particularly limited as long as it can form a conductive pattern substrate having desired conductivity, but is preferably in the range of 0.05 μm to 100 μm, and above all. It is preferably in the range of 0.1 μm to 50 μm, and particularly preferably in the range of 0.5 μm to 10 μm. This is because the effect of the present invention that a high-definition conductive pattern can be obtained can be more effectively exhibited.
The width refers to the width of the widest portion of the distance orthogonal to the wiring direction of the wiring groove portion, and can usually be the distance between the boundaries of the wiring groove portion. Specifically, the width is shown by a in FIG. 1 (a).

The depth of the wiring groove is not particularly limited as long as a desired conductive porous conductive layer can be formed in the wiring groove.
The depth can be, for example, in the range of 0.05 μm to 50 μm, and more preferably in the range of 0.1 μm to 30 μm. The above-mentioned depth refers to the distance between the deepest portion of the wiring groove portion and the upper surface of the wiring groove portion. The upper surface of the wiring groove portion refers to a surface having the same height as the upper surface of the flat surface portion adjacent to the boundary of the wiring groove portion. Specifically, the depth is shown by b in FIG. 1 (a).

The pattern shape of the wiring groove portion in a plan view, that is, the pattern shape of the wiring formed by using the manufacturing method of the present invention in a plan view is appropriately set according to the application of the conductive pattern substrate. is there.
The cross-sectional shape of the wiring groove is not particularly limited as long as it can form a desired conductive porous conductive layer. The cross-sectional shape can be, for example, not only a rectangle but also a wedge shape, a trapezoidal shape, a hemispherical shape, or a combination thereof.

The base material has a groove for wiring, but has a flat surface portion that is the surface of the base material other than the groove for wiring.
The flat surface portion may have an uneven surface, but usually has a flat surface.

The method for forming the base material is not particularly limited as long as it can accurately form the wiring groove portion having a desired cross-sectional shape and a pattern shape in a plan view, but it is preferable to use the imprint method. This is because the imprint method enables the formation of wiring grooves having a predetermined width with high accuracy.
More specifically, the forming method using the imprint method of the base material prepares and supports a template (also referred to as a mold or stamper) in which a concave-convex pattern capable of forming a groove for wiring is formed on the surface. The surface on which the wiring groove is formed by pressing the template against the coating film of the surface layer material coated and formed on the surface of the base material, mechanically deforming the template, and precisely transferring the uneven pattern to the coating film. By forming the layer, it is possible to obtain a base material having a support base material and a surface layer formed on the support base material and having a groove for wiring formed.

As a method for forming the uneven pattern of the template, it can be formed by various commonly used processing techniques. For example, examples of the method for forming the uneven pattern include a wet etching method, a dry etching method, mechanical cutting, laser processing, blast processing, semiconductor lithography, electron beam processing, and the like.

The template material constituting the template may be any material that can accurately transfer the uneven pattern formed on the template to the surface layer material, for example, metals such as quartz, silicon, glass, copper and nickel, organic materials and the like. Can be used.
The surface layer obtained by transferring the uneven pattern of the template to the surface layer material can be further used as a template.
Further, it is preferable that the surface of the template is demolded.

(2) Nanoparticle dispersion liquid The nanoparticle dispersion liquid used in this step contains metal nanoparticles and a dispersion medium.

(A) Metal nanoparticles The metal nanoparticles used in this step may be any metal nanoparticles that can exhibit conductivity when a porous conductive layer is formed.
Such metal nanoparticles include, in addition to metal nanoparticles, alloy nanoparticles, metal compound nanoparticles, and the like.

The metals constituting the metal nanoparticles include precious metals such as gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium, as well as copper, nickel, tin, iron, chromium, molybdenum, aluminum, antimony, and indium. Base metals such as gallium, germanium, zinc, titanium and lead can be mentioned. The metal constituting the metal nanoparticles may be one kind or two or more kinds. Further, those in which two or more kinds of metals form a core-shell structure, those in which the surface of metal nanoparticles is oxidized or nitrided, or the like may be used.
Examples of the metal compound constituting the particles of the metal compound include metal oxides, metal nitrides, metal hydrides, metal hydroxides, and organic metal compounds. It is preferable that these metal compounds are decomposed into a metallic state at the time of firing. For example, particles of a metal compound that is reduced to exhibit conductivity, specifically, particles of a metal compound such as cuprous oxide, cupric oxide, silver oxide, copper nitride, and copper hydride can be mentioned. Examples of the metal oxide include indium tin oxide and antimony-doped tin oxide.
In the present invention, the material constituting the metal nanoparticles is preferably silver or copper, that is, the metal nanoparticles are preferably silver nanoparticles or copper nanoparticles, and particularly copper. That is, it is preferable that the metal nanoparticles are copper nanoparticles. This is because the conductive pattern substrate can be made excellent in conductivity and cost because the material constituting the metal nanoparticles is the above-mentioned material.

The shape of the metal nanoparticles can be a conventionally known shape. Examples of the shape include a substantially spherical shape, a spheroidal shape, a polyhedral shape, a scaly shape, a disc shape, a fibrous shape, a needle shape, and the like. In this step, it is preferable that the shape is substantially spherical. This is because it is easy to control the porosity of the porous conductive layer.
In this step, the substantially spherical shape includes not only a substantially spherical shape that can be approximated to a spherical shape but also a true sphere.

The average primary particle size of the metal nanoparticles is not particularly limited as long as it has a nanometer size.
The average primary particle size is preferably in the range of 1 nm to 200 nm, particularly preferably in the range of 2 nm to 150 nm, and particularly preferably in the range of 10 nm to 100 nm. This is because a porous conductive layer having excellent strength and conductivity can be formed by having the above particle size.
The average primary particle size of the metal nanoparticles can be determined by a method of directly measuring the size of the primary particles from an electron micrograph. Specifically, the particle image is measured by a transmission electron microscope photograph (TEM) (for example, H-7650 manufactured by Hitachi High-Tech), and the average value of the lengths of the longest parts of 100 randomly selected primary particles is calculated. It can be an average primary particle size. The same result can be obtained regardless of whether the electron microscope is a transmission type (TEM) or a scanning type (SEM).

The content of the metal nanoparticles in the nanoparticle dispersion liquid is not particularly limited as long as it can form a porous conductive layer having desired conductivity, but is 50% by mass or more in the solid content. It is preferably in the range of 99.99% by mass, particularly preferably in the range of 80% by mass to 99.9% by mass, and particularly preferably in the range of 85% by mass to 99% by mass. preferable. This is because when the content is within the above range, a coating film broken at the boundary of the wiring groove can be easily formed. Further, it is possible to form a porous conductive layer having excellent strength and conductivity.
The solid content includes all components other than the dispersion medium.

The method for producing the metal nanoparticles is not particularly limited as long as it can produce metal nanoparticles of a desired size, but is physically obtained by pulverizing the conductive material by a mechanochemical method or the like. Methods; chemical dry methods such as CVD method, vapor deposition method, sputtering method, thermal plasma method, laser method; thermal decomposition method, chemical reduction method, electrolysis method, ultrasonic method, laser ablation method, supercritical fluid Examples thereof include a method called a chemical wet method by a method, a microwave synthesis method, or the like.

(B) Dispersion medium The dispersion medium used in this step is not particularly limited as long as it can stably disperse the metal nanoparticles, and for example, water or an organic solvent can be used.
Specific examples of the organic solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin and propylene glycol monomethyl ether, acetone, methyl ethyl ketone and methyl isobutyl. Ketones such as ketones, esters such as methyl acetate, ethyl acetate and propyl acetate, ether alcohol acetates such as methoxyethyl acetate and propylene glycol monomethyl ether acetate, ethers such as ethylene glycol dimethyl ether, and aromatics such as toluene and xylene. Alicyclic hydrocarbons such as hydrocarbons and cyclohexane, hydrocarbons such as aliphatic hydrocarbons such as tetradecane, amides, lactones and the like can be used.

The content of the dispersion medium is not particularly limited as long as it can have a viscosity that allows the nanoparticle dispersion liquid to be stably filled in the groove for wiring.
The content of the dispersion medium is preferably in the range of 5% by mass to 95% by mass, and particularly preferably in the range of 10% by mass to 90% by mass in the nanoparticle dispersion liquid. In particular, it is preferably in the range of 15% by mass to 85% by mass. This is because when the content is within the above range, the nanoparticle dispersion liquid can be stably filled in the wiring groove portion.

(C) Nanoparticle dispersion liquid The nanoparticle dispersion liquid used in this step contains metal nanoparticles and a dispersion medium, but may also contain other components if necessary.
The other components are a dispersion protective agent that covers the surface of the metal nanoparticles for the purpose of stabilizing the metal nanoparticles in a dispersion medium, and a binder for the purpose of improving adhesion to a substrate, film forming property, and printability. It may contain an ingredient.
The other components may contain a viscosity modifier, a surface tension modifier, a stabilizer, and the like, if necessary.
Further, depending on the method for synthesizing metal nanoparticles, the thermal decomposition product or oxide of the raw material may protect the particle surface and contribute to dispersibility. In the case of a wet method such as a thermal decomposition method or a chemical reduction method, the reducing agent or the like may act as a protective agent for metal nanoparticles as it is.

The dispersion protective agent is, for example, a water-soluble polymer such as polyvinylpyrrolidone, a polymer material such as a graft copolymer polymer, a surfactant, a compound having a thiol group, an amino group, a hydroxyl group, or a carboxyl group that interacts with a metal. And the like, low molecular weight materials and the like can be mentioned.

Examples of the binder component include resins such as polyester resin, acrylic resin and urethane resin, and inorganic paints such as ethyl silicate and silicate oligomer.

(3) Coating Method As the coating method of the nanoparticle dispersion liquid in this step, a method capable of coating the nanoparticle dispersion liquid on the entire surface of the base material can be used.
The coating method can be appropriately selected from general coating methods such as a spin coating method, a die coating method, a bar coating method, a gravure coating method, and an inkjet method.

The amount of the nanoparticle dispersion liquid to be applied onto the substrate is appropriately set according to the content of the dispersion medium contained in the nanoparticle dispersion liquid, the thickness of the target coating film, and the like.

2. Drying Step The drying step in the present invention is a step of drying the nanoparticle dispersion liquid coated on the base material to form a coating film containing the metal nanoparticles.

The method for drying the nanoparticle dispersion liquid in this step is not particularly limited as long as it can dry and remove the dispersion medium contained in the nanoparticle dispersion liquid, and a known drying method is used. Can be done.
Specific examples of the drying method include vacuum drying, heat drying, and a combination thereof. When drying at normal pressure, it is preferable to dry in a temperature range in which the base material does not deteriorate.
More specifically, the drying method can be a method of heat-treating at a temperature in the range of 50 ° C. to 300 ° C. for about 1 minute to 120 minutes. Further, the atmosphere at the time of heat treatment can be an atmosphere under the atmosphere or an atmosphere containing oxygen.

The coating film formed by this step is preferably broken at the boundary of the wiring groove.
Here, the term “broken at the boundary” is not limited to the one that is broken at all of the above boundaries in plan view, but also includes the one that is broken at a part of the boundary.
In this step, it is particularly preferable that the coating film is broken at all of the above boundaries in a plan view. This is because the porous conductive layer formed on the surface of the base material other than the wiring groove portion can be easily peeled off in the peeling step.

The thickness of the coating film formed by this step is particularly limited as long as the porous conductive layer formed in the wiring groove portion by the sintering step can have desired conductivity. It's not a thing.
In this step, the upper surface of the coating film formed in the wiring groove is preferably the same as or lower than the upper surface of the wiring groove, and more preferably lower than the upper surface of the wiring groove. This is because it is easy for the coating film to be broken at the boundary of the wiring groove. Further, the upper surface of the porous conductive layer formed in the wiring groove in the firing step can be the same as or lower than the upper surface of the wiring groove, and the porous conductive layer in the wiring groove can be formed in the peeling step. This is because it can be left stable. For example, when the peeling step uses an adhesive tape as a peeling base material to peel off the porous conductive layer on the flat surface portion, it is possible to effectively prevent the adhesive tape from coming into contact with the porous conductive layer in the wiring groove portion. Because.
The upper surface of the coating film refers to the outermost surface side of the coating film in the wiring groove. FIG. 1C, which has already been described, is a schematic cross-sectional view showing an example in which the upper surface of the coating film is the same as the upper surface of the wiring groove portion. FIG. 2 is a schematic cross-sectional view showing an example in which the upper surface of the coating film is lower than the upper surface of the wiring groove portion.

The thickness of the coating film formed on the flat surface portion is not particularly limited as long as it can form a porous conductive layer that can be easily peeled off, but is within the range of 0.01 μm to 50 μm. It is preferably in the range of 0.1 μm to 30 μm, and particularly preferably in the range of 0.2 μm to 20 μm. This is because when the thickness is within the above range, it is easy for the coating film to be broken at the boundary of the wiring groove portion. Further, it is possible that the porous conductive layer formed on the flat surface portion is bonded with sufficient strength in the plane direction. Therefore, the porous conductive layer can be easily peeled off in the peeling step.
The thickness of the coating film on the flat surface portion refers to the thickness at the thickest portion of the coating film on the flat surface portion. The thickness is specifically the distance indicated by c in FIG. 1 (c) already described.

3. 3. Sintering step The sintering step in the present invention is a step of sintering the metal nanoparticles contained in the coating film to form a porous conductive layer.

Here, sintering means that metal nanoparticles are heated and melted and adjacent metal nanoparticles are bonded to each other so as to be integrated, thereby forming a film in which a part or the whole of the metal nanoparticles is continuously bonded. It means forming.

The sintering method in this step is not particularly limited as long as it can sinter the metal nanoparticles with each other to form a porous conductive layer, and examples thereof include a method of firing the coating film. it can.
Examples of the firing method include heat treatment, light treatment, plasma treatment, and the like.
Examples of the heat treatment include hot plate heating, hot air heating, and a hot press method using a hot plate or a hot roll.
Examples of the light treatment include laser treatment, ultraviolet lamp treatment, infrared lamp treatment, far infrared lamp treatment, flash light lamp treatment and the like.
The plasma treatment is a treatment in which gases such as hydrogen, carbon monoxide, ammonia, and alcohol, which exhibit reducing properties, are ionized into a plasma state to generate a highly reactive active species. For example, electron cyclotron resonance (ECR). Examples thereof include plasma, capacitively coupled plasma, inductively coupled plasma, atmospheric pressure plasma, microwave plasma, and surface wave plasma generated by application of microwave energy.
In the present invention, among them, the firing method is plasma treatment using surface wave plasma (hereinafter, may be referred to as surface wave plasma treatment), that is, the sintering step is surface wave plasma treatment. It is preferable that the metal nanoparticles are sintered with each other by firing the coating film. Surface wave plasma treatment tends to promote sintering of metal nanoparticles from the surface side of the coating film. Therefore, heat damage to the base material can be suppressed. Further, it is easy to sinter so that the bottom side is less sintered than the surface side, and the metal nanoparticles contained in the coating film in the wiring groove are sintered on the bottom side from the surface side. Can be sintered so that the amount of particles is reduced. This is because a porous conductive layer having excellent adhesion to the base material can be formed in the groove portion for wiring.
The above sintering method can be used in combination of two or more.

The method for generating the surface wave plasma may be any method as long as the metal nanoparticles can be sintered to a desired degree. For example, microwave energy is supplied from the irradiation window of the firing treatment chamber in a reduced pressure state to perform the firing treatment. An electrodeless plasma generating means for generating surface wave plasma along the irradiation window in the room can be used.

As the microwave energy, an electromagnetic wave having a frequency of 300 MHz to 3000 GHz can be used, and preferably an electromagnetic wave having a frequency of 2450 MHz can be used. At this time, it is possible to have a frequency range of 2450 MHz ± 50 MHz due to an accuracy error of the magnetron which is a microwave oscillator.
The micro surface wave plasma generated in the processing chamber can have an electron temperature of about 1 eV or less and an electron density of about 1 × 10 ¹¹ cm ^-3 to 1 × 10 ¹³ cm ^-3 .

The atmosphere at the time of firing is appropriately selected according to the type of the conductive material constituting the porous conductive layer.
When forming the porous conductive layer containing a metal, the atmosphere is preferably an inert gas or a reducing gas, and more preferably a reducing gas. In particular, when the metal is a base metal, it is preferable that the atmosphere is a reducing gas. In the case of a reducing gas atmosphere, the oxide existing on the surface of the metal nanoparticles is reduced and removed, and a porous conductive layer having good conductivity can be formed. Therefore, when forming a porous conductive layer containing a metal, metal nanoparticles whose surface is oxidized or metal nanoparticles whose surface is oxidized can be used as the metal nanoparticles.

Examples of the reducing gas include hydrogen, carbon monoxide, ammonia, and a mixed gas thereof. Of these, hydrogen gas is preferable as the reducing gas. Hydrogen gas is suitable for removing organic substances adhering to the surface of metal nanoparticles.
The reducing gas may be mixed with an inert gas such as nitrogen, helium, argon, neon, krypton, or xenon. In this case, there is an effect that plasma is easily generated.

On the other hand, when the porous conductive layer containing a metal oxide is formed, the atmosphere at the time of firing may be an atmosphere containing an inert gas such as nitrogen or argon and, if necessary, oxygen.

Further, when forming a porous conductive layer containing copper, the firing method is preferably a method using hydrogen plasma or nitrogen plasma. ^{This is because a specific resistance of about 3 × 10 -6} Ω · cm to 3 × 10 ^-5 Ω · cm can be obtained by using hydrogen plasma in particular.

The firing temperature may be any temperature at which the metal nanoparticles can be sintered, and is appropriately selected depending on the type and particle size of the metal nanoparticles, the firing method, and the like. Above all, the firing temperature is preferably equal to or lower than the heat resistant temperature of the base material, and in the case of silver particles as an example, it is preferably in the range of 100 ° C. to 150 ° C.
The firing time is appropriately selected according to the type of metal nanoparticles, the firing method, and the like. For example, when silver nanoparticles are fired by heat treatment, the firing time is preferably in the range of 10 minutes to 120 minutes, particularly preferably in the range of 15 minutes to 40 minutes. Further, for example, when copper nanoparticles are fired by hydrogen plasma, the firing time is preferably in the range of 1 minute to 10 minutes, particularly preferably in the range of 2 minutes to 5 minutes.

The porous conductive layer formed by this step refers to a conductive layer having a large number of pores, and has a larger surface area than a conductive layer having the same volume and no pores.
In such a porous conductive layer, the degree of sintering of metal nanoparticles may be uniform in the thickness direction, but in the porous conductive layer in the groove for wiring, the degree of sintering on the bottom side is higher than that on the surface side. It is preferably sintered so as to be low. This is because the degree of sintering of the metal nanoparticles on the bottom side is low, so that a porous conductive layer having excellent adhesion to the base material can be formed in the groove portion for wiring.
Here, regarding the degree of sintering, the lower the degree of sintering, the more the metal nanoparticles as the raw material retain the prototype. Therefore, when the degree of sintering is lower on the bottom side than on the surface side, it can be confirmed that the particle shape is maintained toward the bottom side.
As a method for confirming the extent to which the metal nanoparticles retain their original shape, for example, a method of observing a cross section of the porous conductive layer using a scanning electron microscope (SEM) can be used.
Further, the lower the degree of sintering, the larger the residue derived from organic substances such as resin added to the nanoparticle dispersion liquid. Therefore, when the degree of sintering is low, it can be confirmed that the residual amount of organic matter is large.

The porosity of the porous conductive layer formed by this step is not particularly limited as long as the porous conductive layer on the flat surface portion can be easily peeled off.
The porosity of the porous conductive layer on the flat surface portion is preferably in the range of 5% to 50%, particularly preferably in the range of 10% to 45%, and particularly 15%. It is preferably in the range of ~ 40%. This is because when the porosity is within the above range, the porous conductive layer can be bonded with sufficient strength in the plane direction. Therefore, the porous conductive layer can be easily peeled off in the peeling step.
The porosity can be measured by the following method. That is, a cross-sectional observation of the porous film is performed using a scanning electron microscope (SEM), the area of the pores and the area of the porous conductive layer are calculated from the obtained SEM image, and the area of the pores is determined by the porous conductivity. The porosity in the cross section can be obtained by dividing by the area of the layer. The porosity is calculated from the porous conductive layer excluding the base material, and the pores at the interface between the base material and the porous conductive layer are included in the porous conductive layer.
Then, the porosity is similarly obtained for a plurality of cross sections according to the size of the conductive pattern substrate, and the average value is taken as the porosity of the porous conductive layer.
The area for observing the cross section can be 50 nm × 50 nm or more at each location.
Further, the average value of the porosity can be more specifically the average value of the porosity obtained at 10 or more randomly selected locations.

Among the porous conductive layers, the adhesion of the porous conductive layer on the flat surface to the base material is as follows: the porous conductive layer in the wiring groove is left by the peeling step, and the porous conductive layer is porous on the flat surface. It suffices as long as only the conductive layer can be peeled off, and it can be appropriately set according to the peeling method and the like in the peeling step.

The thickness of the porous conductive layer can be the same as that of the coating film.

4. Peeling Step The peeling step in the present invention is a step of peeling the porous conductive layer formed on the surface of the base material other than the groove for wiring.

The method for peeling off the porous conductive layer in this step is particularly limited as long as it can peel off and remove the porous conductive layer formed on the flat surface portion and leave the porous conductive layer in the groove for wiring. It's not something.
In the present invention, in the peeling method, the peeling base material having adhesiveness or adhesiveness is brought into contact with only the porous conductive layer formed on the surface of the base material other than the wiring groove portion, and then the peeling is performed. A method of peeling the porous conductive layer together with the base material is preferable. This is because the porous conductive layer can be easily peeled off.

The peeling base material having the adhesiveness or the adhesiveness may be any one as long as it adheres to the porous conductive layer and can peel off the porous conductive layer from the flat surface portion.
Such a peeling base material may have a supporting base material and an adhesive layer formed on the supporting base material and containing an adhesive or an adhesive layer containing an adhesive.
The shape of the supporting base material may be a film shape or a roller shape. That is, the peeling base material shall be a peeling film having adhesiveness or adhesiveness such as an adhesive tape or a slightly adhesive tape, a peeling roller having adhesiveness or adhesiveness such as an adhesive roller or a slightly adhesive roller. Can be done.
As the adhesive contained in the adhesive layer and the adhesive contained in the adhesive layer, the adhesive force between each of the adhesive layer and the adhesive layer and the porous conductive layer is higher than the adhesive force between the base material and the porous conductive layer. It suffices as long as it becomes large, and can be appropriately selected from general adhesives and adhesives.
The supporting base material may be any material that can support the adhesive layer or the adhesive layer, and examples thereof include a glass base material and a resin base material.

The porous conductive layer left in the wiring groove portion by this step is used as wiring in the conductive pattern substrate.

5. Method for Manufacturing Conductive Pattern Substrate The method for manufacturing a conductive pattern substrate of the present invention includes the above-mentioned coating step, drying step, sintering step, and peeling step, but includes other steps as necessary. May be good.
Examples of the other steps include a protective layer forming step of forming a protective layer so as to cover the porous conductive layer formed in the wiring groove after the peeling step.
The material constituting the protective layer may be any material having an insulating property, and may be, for example, the same as the constituent material of the base material.

As an application of the method for manufacturing a conductive pattern substrate of the present invention, it is preferable to use it for manufacturing a conductive pattern substrate that requires a high-definition conductive pattern, and in particular, it is used as a transparent conductive substrate with a narrow wiring width. It is preferably used in the manufacture of conductive patterned substrates.
More specifically, the conductive pattern substrate can be used for a transparent conductive film, an electromagnetic wave shielding material, an antenna, a noise filter, a touch panel sensor, a light emitting element, a display electrode, a solar cell electrode, and the like.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

[Synthesis example: Synthesis of copper particles]
10.0 g of copper hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.), 34.5 g of decanoic acid (manufactured by Kao Lunac 10-98), and 18.5 g of propylene glycol monomethyl ether (PGME) were weighed in a 200 ml three-necked flask. .. The mixture was heated to 100 ° C. with stirring and maintained at that temperature for 20 minutes. Then, 41.3 g of 3-ethoxypropylamine (manufactured by Koei Chemical Industry Co., Ltd.) was added, and the mixture was heated at 100 ° C. for 10 minutes and stirred. This mixed solution was cooled to 10 ° C. using an ice bath, and then a solution prepared by dissolving 10.0 g of hydrazine monohydrate in 18.5 g of PGME (manufactured by Kanto Chemical Co., Inc.) was added in the ice bath for 10 minutes. Stirred. Then, the reaction solution was heated to 100 ° C. and the temperature was maintained for 10 minutes. After cooling to 30 ° C., 66 g of hexane was added. After centrifugation, the supernatant was removed. The precipitate was washed with hexane to give copper particles.
When the obtained copper particles were observed with a transmission electron microscope (TEM), the average primary particle size was 65 nm.

[Production example Preparation of copper nanoparticle dispersion liquid]
A copper nanoparticle dispersion was prepared by the following procedure. 3.0 parts by mass of copper particles obtained in the synthesis example, 0.3 parts by mass of Solsperse 41000 (manufactured by Nippon Lubrizol), and 4.2 parts by mass of PGME were mixed and used as a preliminary dispersion with a paint shaker (manufactured by Asada Iron Works). The mixture was dispersed with 2 mm zirconia beads for 1 hour and further with 0.1 mm zirconia beads for 2 hours as the main dispersion to obtain a copper nanoparticle dispersion liquid.

[Manufacturing example Production of a base material having a groove for wiring]
Two types of line-shaped groove patterns having different widths formed by an etching method were prepared on a silicon base material, and the one transferred to a dimethylpolysiloxane film was used as a master plate.
The two types of groove patterns on the line had a width of 1.0 μm and a width of 2.0 μm, a length of 10 mm, a depth of 5.0 μm, and a rectangular cross-sectional shape.
Next, an ultraviolet curable resin was applied to a 100 μm-thick PET film (Cosmoshine A4100) prepared as a support base material, and a master plate was superposed on the UV curable resin (Seika Beam PCD04, manufactured by Dainichiseika). On the other hand, the master plate was removed after exposure from the base material side with an integrated exposure amount of ^{200 mJ / cm 2} using an ultraviolet lamp (H valve manufactured by Fusion UV Systems). As a result, a base material was obtained in which the ultraviolet curable resin was cured and formed on the support base material and had a surface layer having a groove for wiring. It was confirmed by scanning electron microscope (SEM) that there are two types of wiring grooves, one with a width of 1.0 μm and the other with a width of 2.0 μm, each having a depth of 3.5 μm, and the cross-sectional shape being rectangular. did.

[Example 1]
The copper nanoparticle dispersion liquid prepared in the production example was applied to a substrate having a wiring groove prepared in the production example with a bar coater, and dried in an oven at 80 ° C. for 2 minutes to form a coating film. When the coating film was observed with a microscope, it was confirmed that the coating film was broken at the boundary of the wiring groove.
Then, while introducing hydrogen gas at an introduction pressure of 20 Pa, the coating film was fired at a microwave output of 450 W for 240 seconds using a microwave surface wave plasma processing device (MSP-1500, manufactured by Microelectronics Co., Ltd.) to obtain copper. A porous copper layer was formed in which the particles were sintered. As a result, a conductive substrate was obtained.
As a result of microscopic observation, it was confirmed that the obtained porous copper layer had fractures at the boundary of the wiring groove.
Subsequently, when the adhesive tape as the peeling base material was brought into contact with only the porous copper layer formed on the base material surface other than the wiring groove portion and then peeled off, it was formed on the base material surface other than the wiring groove portion. The porous copper layer was able to be peeled off. As a result, a conductive pattern substrate was obtained.
After that, as a result of observing the porous copper layer remaining in the wiring groove with a microscope, it was confirmed that a porous copper layer without disconnection was obtained in the wiring groove. In addition, no residue of the porous copper layer was observed other than the surface of the base material other than the groove for wiring.
The results of observing the conductive substrate and the conductive pattern substrate with a microscope are shown in FIG. FIG. 3 shows the observation results around the 2.0 μm wide wiring groove portion of the conductive substrate and the conductive pattern substrate, FIG. 3 (a) is observation of transmitted light, and FIG. 3 (b) is observation of reflected light. .. In FIG. 3A, light transmission was observed at the boundary of the wiring groove, and it was confirmed that breakage occurred at the boundary of the wiring groove. Further, in FIG. 3B, it was confirmed that only the portion of the wiring groove portion was colored in copper color, and the flat portion was observed through the color of the stage.

[Example 2]
Silver nanoparticle ink (trade name: MDot CF107, manufactured by Samsung Belt, average primary particle size of silver particles; 100 nm or less) is diluted with methanol so that the content of silver nanoparticles in the silver nanoparticle dispersion is 40% by mass. Then, a silver nanoparticle dispersion liquid was obtained.
A coating film was formed by applying a silver nanoparticle dispersion liquid with a bar coater to a base material having a groove for wiring prepared in the production example, and then drying the dispersion medium. When the coating film was observed with a microscope, it was confirmed that the coating film was broken at the boundary of the wiring groove.
Next, the base material was heated in a hot air furnace at 120 ° C. for 30 minutes to fire the coating film, and the silver nanoparticles contained in the coating film were sintered. As a result, a conductive substrate was obtained.
As a result of microscopic observation, it was confirmed that the obtained porous silver layer was broken at the boundary of the wiring groove.
Subsequently, when the adhesive tape as the peeling base material was brought into contact with only the porous silver layer formed on the base material surface other than the wiring groove portion and then peeled off, it was formed on the base material surface other than the wiring groove portion. The porous silver layer was able to be peeled off. As a result, a conductive pattern substrate was obtained.
After that, as a result of observing the porous silver layer remaining in the wiring groove with a microscope, it was confirmed that a porous silver layer without disconnection was obtained in the wiring groove. In addition, no residue of the porous silver layer was observed other than the surface of the base material other than the groove for wiring.

[Evaluation]
(Measurement of film thickness of porous conductive layer)
The film thickness of the conductive substrate and the conductive pattern substrate obtained in the above examples was evaluated. Regarding the conductive substrate and the conductive pattern substrate produced in each example, carbon was sequentially laminated on the upper part of the porous conductive layer as a protective layer by a vacuum deposition method and platinum by a sputtering method, and then FIB (focused ion beam, Hitachi High-Tech). After laminating tungsten using FB-2100), a cross section of a porous conductive layer was prepared.
Then, using SEM (S-4800 manufactured by Hitachi High-Tech), the cross section of the porous conductive layer was observed with the base material tilted by 45 °, and the film thickness was measured from the SEM image. The film thickness was measured at 10 points in the SEM image measured at a magnification of 30 k to 40 k, the inclination was corrected, and the average value was taken as the film thickness.
In the conductive substrate of Example 1, the film thickness of the porous copper layer formed on the surface of the base material other than the wiring groove was 250 nm.
As a result of observing the cross section of the conductive pattern substrate of Example 1, it was confirmed that both the 1.0 μm width and the 2.0 μm width wiring grooves were filled with the porous copper layer. The film thicknesses of the porous copper layers in the wiring grooves having a width of 1.0 μm and a width of 2.0 μm were 1.5 μm and 1.5 μm, respectively.
In the conductive substrate of Example 2, the film thickness of the porous silver layer formed on the surface of the substrate other than the wiring groove was 200 nm.
As a result of observing the cross section of the conductive pattern substrate of Example 2, it was confirmed that both the 1.0 μm width and the 2.0 μm width wiring grooves were filled with the porous silver layer. The film thicknesses of the porous silver layers in the wiring grooves having a width of 1.0 μm and a width of 2.0 μm were 0.7 μm and 3.0 μm, respectively.
FIG. 4 shows an SEM image around the 1.0 μm wide wiring groove portion of Example 1.

(Measurement of porosity)
The porosity of the porous conductive layer formed in the wiring groove of the conductive patterned substrate produced in the example was measured.
For the measurement, an SEM image taken at a magnification of 30 k to 40 k by the same method as the above-mentioned "Measurement of film thickness of the porous conductive layer" was used.
The porosity was determined by measuring at 10 different locations of the porous conductive layer and averaging (the total porosity at each location divided by 10).
The porosity was measured at each location within a 700 nm × 700 nm square cross section in the SEM image.
As a result, the porosity of the porous conductive layer of Example 1 was 35%, and the porosity of the porous conductive layer of Example 2 was 30%.

(Measurement of sheet resistance of porous conductive layer)
The conductivity of the porous conductive layer formed on the surface of the base material other than the wiring groove portion of the conductive substrate obtained in the examples was evaluated. To measure the sheet resistance value of the porous conductive layer, use a surface resistance meter (“Loresta GP” manufactured by Dia Instruments, PSP probe type) to bring the 4-probe into contact with the porous conductive layer and use the 4-probe method. This was done by measuring the sheet resistance value.
The sheet resistance value of the porous copper layer of Example 1 was 0.25 Ω / □, and the sheet resistance value of the porous silver layer of Example 2 was 0.19 Ω / □.

1 ... Base material 1a ... Wiring groove 1b ... Flat surface 2 ... Nanoparticle dispersion liquid 3 ... Coating film 4 ... Porous conductive layer 5 ... Peeling base material 10 ... Conductive pattern substrate

Claims (3)

A base material having a wiring groove on one surface, which is a groove on which wiring is formed, is prepared by using the imprint method.
A coating step of applying a nanoparticle dispersion liquid containing metal nanoparticles and a dispersion medium to the surface of the base material on which the wiring groove is formed.
A drying step of drying the nanoparticle dispersion liquid applied on the base material to form a coating film containing the metal nanoparticles, and a drying step.
A sintering step of sintering the metal nanoparticles contained in the coating film to form a porous conductive layer.
A peeling step of peeling the porous conductive layer formed on the surface of the base material other than the wiring groove portion, and
Have,
Wherein In the baking step, the porous conductive layer of the wiring groove portion, the conductive pattern producing method of the substrate bottom side the degree of sintering from the surface side, characterized in der Rukoto those sintered as lower. The method for manufacturing a conductive pattern substrate according to claim 1, wherein the metal nanoparticles are silver nanoparticles or copper nanoparticles. The conductive pattern substrate according to claim 1 or 2, wherein the sintering step is to sinter the metal nanoparticles with each other by firing the coating film by surface wave plasma treatment. Manufacturing method.

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