JP2018041697A - Dispersion and substrate for the production of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion that can form a low-resistant wire on a low heat-resistant resin substrate, and a substrate for the production of a printed wiring board having a film formed using the same.SOLUTION: A dispersion has particles containing metal and/or metal oxide, and nonvolatile organic matter. The particles have a primary particle size of 5 nm or more and less than 100 nm, the nonvolatile organic matter contains nitrogen-containing organic matter, and the nonvolatile organic matter has a nitrogen content of 6 mass% or more and 55 mass% or less.SELECTED DRAWING: None

Description

  The present invention relates to a dispersion. The present invention also relates to a printed wiring board manufacturing substrate having a film formed using the dispersion of the present invention.

  The circuit board has a structure in which conductive wiring is provided on the board. Conventional methods for manufacturing such a circuit board generally apply a photoresist on a substrate on which a metal foil is bonded, and expose and develop it to obtain a negative shape of a desired circuit pattern. And removing a portion of the metal foil not covered with the photoresist by chemical etching to form a pattern. The conventional manufacturing method of a circuit board can manufacture a high-performance conductive substrate. However, the conventional method for manufacturing a circuit board has a number of steps, is complicated, and has the disadvantages of requiring a photoresist material.

  In contrast, a method including directly printing a desired wiring pattern on a substrate using a dispersion in which particles containing metal and metal oxide are dispersed (hereinafter also referred to as “conductive paste”) is noted. Has been. Such a method of directly printing a desired wiring pattern on a substrate has extremely high productivity because the number of steps is small and it is not necessary to use a photoresist material.

  However, generally used conductive paste uses silver fine particles as particles containing metal and metal oxide, and silver is very expensive, so there is a cost merit brought by productivity improvement by direct printing method. It will be offset. Also, silver is known to easily migrate, and wiring using silver paste has low reliability.

  Many electroconductive pastes using copper fine particles have been studied for these problems.

  For example, Patent Document 1 discloses a copper paste containing copper powder, non-lead glass frit, copper oxide, a resin binder, and a thixotropic agent.

  Patent Document 2 discloses a dispersion containing copper nanoparticles and ethyl cellulose. By using copper nanoparticles having a particle diameter of about 100 nm, firing can be performed at 500 ° C.

JP 2012-54113 A JP 2012-52240 A

  However, in the method described in Cited Document 1, since particles having a large particle size are used, a high temperature of 900 ° C. is necessary for firing. Moreover, although the baking temperature is 500 degreeC by the method of the cited reference 2, since a resin base material cannot be used at 500 degreeC, there exists room for further temperature reduction. Further, the copper nanoparticles were easily oxidized, and the dispersibility of the nanoparticles deteriorated due to the oxidation, and the aggregation proceeded. Therefore, the dispersion could not be stored for a long time.

  Therefore, the problem to be solved by the present invention is to provide a dispersion capable of forming a low resistance wiring on a low heat resistant resin substrate, and a printed wiring board manufacturing substrate having a film formed using the same. Is to provide.

  The present inventors diligently researched and conducted experiments in order to achieve the above-mentioned problems. As a result, it has been found that the above problems can be achieved by using a dispersion containing particles containing a metal or metal oxide and a nonvolatile organic substance containing a specific amount of nitrogen, and the present invention is based on this. Is completed.

That is, the present invention is as follows.
[1]
Particles comprising metal and / or metal oxide;
A dispersion containing non-volatile organic matter,
The primary particle diameter of the particles is 5 nm or more and less than 100 nm,
The non-volatile organic substance contains a nitrogen-containing organic substance, and the nitrogen content of the non-volatile organic substance is 6% by mass or more and 55% by mass or less.
[2]
The nitrogen-containing organic substance has at least one selected from a nitrate ester structure, a nitro group, a cyano group, and a heterocyclic structure containing nitrogen.
Item 4. The dispersion according to item 1.
[3]
The nitrogen-containing organic substance has an aldose structure,
Item 3. The dispersion according to item 1 or 2.
[4]
The particles include particles composed of copper oxide,
Item 4. The dispersion according to item 1.
[5]
A printed wiring board manufacturing substrate having a base material and a film formed on the base material, wherein the film is
Particles comprising metal and / or metal oxide;
Containing non-volatile organic matter,
The primary particle diameter of the particles is 5 nm or more and less than 100 nm,
The non-volatile organic substance contains a nitrogen-containing organic substance, and the nitrogen content of the non-volatile organic substance is 6% by mass or more and 55% by mass or less.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate for printed wiring board manufacture which has a dispersion | distribution which can form low resistance wiring on a low heat resistant resin substrate, and a film | membrane formed using this can be obtained.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described in detail, but the present invention is not limited to this embodiment. In the present specification, the upper limit value and the lower limit value of each numerical range can be arbitrarily combined.

<Dispersion>
The dispersion of the present embodiment contains particles containing a metal and / or metal oxide and a non-volatile organic substance, the primary particle diameter of the particle is 5 nm or more and less than 100 nm, and the nitrogen content of the non-volatile organic substance Is 6 mass% or more and 55 mass% or less.

[particle]
The particles in the dispersion according to the present embodiment are particles containing a metal and a metal oxide. The metal and metal oxide are at least one selected from the group consisting of gold, silver, copper, nickel, cobalt, tin, lead, indium, aluminum, zirconium, cerium, hafnium, and magnesium, and oxides of these metals. May be one. Copper and copper oxide are preferable because they are inexpensive and can form wiring with low resistance by firing. Specific examples of the particles containing copper and copper oxide may be, for example, particles composed of copper, cuprous oxide, cupric oxide, copper oxide having other oxidation numbers, and the like, and the core portion. May be a particle having a core / shell structure in which is a copper and the shell portion is copper oxide. As the copper oxide, cuprous oxide and cupric oxide are preferable because they tend to be excellent in dispersibility and are chemically stable, and cuprous oxide is particularly preferable because it tends to be sintered at low temperature. The particles containing a metal and a metal oxide may contain a metal salt or a metal complex or both as a small amount of impurities. As the particles containing a metal and a metal oxide, one kind may be used alone, or a plurality kinds may be mixed and used.

  The average secondary particle size of the particles contained in the dispersion of the present embodiment is not particularly limited, but is preferably 1,000 nm or less, more preferably 500 nm or less, still more preferably 200 nm or less, and particularly preferably 80 nm or less. The average secondary particle size of the particles is preferably 5 nm or more, more preferably 15 nm or more, and further preferably 20 nm or more. The average secondary particle size is the average particle size of aggregates (secondary particles) formed by collecting a plurality of primary particles. The average secondary particle size is preferably 1,000 nm or less because it tends to be fired at a low temperature. An average secondary particle size of 5 nm or more is preferable because long-term storage stability of the dispersion is improved. The average secondary particle size of the particles can be measured by a cumulant method using, for example, FPAR-1000 manufactured by Otsuka Electronics.

  The average primary particle size of the primary particles constituting the secondary particles is preferably less than 100 nm, more preferably less than 50 nm, and even more preferably less than 20 nm. The average primary particle size is preferably 1 nm or more, more preferably 2 nm or more, and further preferably 5 nm or more. When the average primary particle size is 100 nm or less, it tends to be possible to lower the firing temperature described later, and the smaller the average primary particle size, the lower the firing temperature, which is preferable. The reason why such low-temperature firing is possible is considered to be that the smaller the particle diameter, the greater the surface energy and the lower the melting point. Moreover, it is preferable if the average primary particle size is 1 nm or more because good dispersibility can be obtained. The average primary particle size can be measured with a transmission electron microscope or a scanning electron microscope.

  It is preferable that the content rate of the particle | grains in the dispersion of this embodiment is 0.50 mass% or more and 70 mass% or less with respect to the total mass of a dispersion, More preferably, it is 1.0-60 mass%, Furthermore, Preferably it is 5.0-50 mass%. If the content is 70% by mass or less, the aggregation of particles tends to be easily suppressed. When the content is 0.50% by mass or more, the conductive film obtained by firing is not excessively thin and the conductivity tends to be favorable, which is preferable.

  As the particles in the present embodiment, commercially available products may be used, or synthetic products may be used. As a commercial item, the cupric oxide particle with an average primary particle diameter of 50 nm made from CIK nanotech is mentioned, for example.

Examples of the particle synthesis method include the following methods.
(1) Add water and a copper acetylacetonate complex to a polyol solvent, once dissolve the organic copper compound by heating, add further water in an amount necessary for the reaction, and heat to the reduction temperature of the organic copper for reduction. Method.
(2) A method of heating an organic copper compound (copper-N-nitrosophenylhydroxylamine complex) at a high temperature of about 300 ° C. in an inert atmosphere in the presence of a protective agent such as hexadecylamine.
(3) A method of reducing a copper salt dissolved in an aqueous solution with hydrazine.

  The method (1) can be carried out under the conditions described in, for example, Angelevante Chemi International Edition, No. 40, Vol. 2, p. 359, 2001.

  The method of (2) is described, for example, in Journal of American Chemical Society 1999, 121, p. It can be carried out under the conditions described in 11595.

  In the method (3), a divalent copper salt can be suitably used as the copper salt. Examples thereof include copper (II) acetate, copper (II) nitrate, copper (II) carbonate, Examples thereof include copper (II) chloride and copper (II) sulfate. The amount of hydrazine used is preferably 0.2 mol to 2 mol, more preferably 0.25 mol to 1.5 mol, per 1 mol of copper salt.

  A water-soluble organic compound may be added to the aqueous solution in which the copper salt is dissolved. Since the melting point of the aqueous solution is lowered by adding a water-soluble organic compound to the aqueous solution, reduction at a lower temperature is possible. As the water-soluble organic compound, for example, alcohol, water-soluble polymer and the like can be used.

  As the alcohol, for example, methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, ethylene glycol, propylene glycol, glycerin and the like can be used. As the water-soluble polymer, for example, polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol copolymer and the like can be used.

  The temperature at the time of reduction in the method (3) can be, for example, −20 to 60 ° C., and preferably −10 to 30 ° C. This reduction temperature may be constant during the reaction, or may be raised or lowered during the reaction. In the initial stage of the reaction when the activity of hydrazine is high, the reduction is preferably 10 ° C. or less, and more preferably 0 ° C. or less. The reduction time is preferably 30 minutes to 300 minutes, and more preferably 90 minutes to 200 minutes. The atmosphere during the reduction is preferably an inert atmosphere such as nitrogen or argon.

  Among the methods (1) to (3), the method (3) is preferable because the operation is simple and particles having a small particle diameter are obtained.

[Non-volatile organic matter]
The dispersion of this embodiment contains a non-volatile organic material for the purpose of improving printability, long-term storage stability, and lowering the firing temperature.

  The nonvolatile organic substance in the present embodiment may be a single compound or a mixture of a plurality of compounds. Here, the non-volatile organic substance refers to an organic component that remains on the substrate after the dispersion is applied on the substrate and dried at 100 ° C. for 30 minutes.

  The nonvolatile organic substance in the present embodiment contains a nitrogen-containing organic substance, and the nitrogen content of the nonvolatile organic substance is 6% by mass or more and 55% by mass or less. The nitrogen content of the nonvolatile organic material is preferably 7.5% by mass or more, more preferably 10% by mass or more, preferably 21% by mass or less, more preferably 13% by mass or less. If the nitrogen content is 6% by mass or more, the dispersibility of the particles is improved, and if it is 7.5% by mass or more, the organic matter is decomposed at a lower temperature, so that the firing can be performed at a lower temperature. If it exists, since the residue after baking becomes difficult to remain, the conductive film obtained becomes lower resistance. If the nitrogen content is 55% by mass or less, it is excellent in chemical stability and excellent in long-term storage, and if it is 50% by mass or less, it is excellent in chemical stability and can be stored for a long time. In the present specification, the nitrogen content means mass% of nitrogen contained in the non-volatile organic substance. The nitrogen content can be measured by elemental analysis.

  The nonvolatile organic material in the present embodiment includes an organic material having a structure containing nitrogen (also referred to as “nitrogen-containing organic material” in the present specification). Examples of the structure containing nitrogen include a functional group containing nitrogen, a bond containing nitrogen, a heterocyclic structure containing nitrogen, and other structures containing nitrogen.

  Specific examples of the functional group containing nitrogen include an amino group, a nitro group, a nitroso group, a cyano group, an isocyanate group, an azide group, and an isocyano group. An organic substance having at least one group selected from a nitro group, a cyano group, and an amino group is preferable because the dispersibility of the particles is improved. In particular, an organic substance having a nitro group and / or a cyano group is preferable because it has a low decomposition temperature and can be baked at a low temperature.

  Specific examples of the bond containing nitrogen include an imide bond, an amide bond, a urethane bond, an ionic bond, a hydrogen bond, and a coordination bond. In particular, an organic substance having an amide bond and / or a urethane bond is preferable because it easily decomposes and can be fired at a low temperature.

  Specific examples of the heterocyclic structure containing nitrogen include ethyleneimine, azirine, azacyclobutane, azeto, 2-pyrrolidone, pyrrolidine, pyrrole, piperidine, pyridine, pyrimidine, pyridazine, pyrazine, triazine, hexamethyleneimine, azatropylidene, Imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, imidazoline, pyrazine, morpholine, thiazine, indole, isoindole, benzimidazole, purine, quinoline, isoquinoline, quinazoline, quinoxaline, phthalazine, cinnoline, pteridine, 1,4- Benzodiazepine, acridine, phenoxazine, phenothiazine, carbazole, phenanthroline, porphyrin, chlorin, choline, benzo-c-sinoli , Piperazine, quinuclidine, azetidin-2-one, and tropane the like.

  Specific examples of other structures containing nitrogen include enamines, imines, oximes, lactams, lactims, amidines, nitrones, and nitrate esters. An organic substance having a lactam structure is preferable because the dispersibility of the particles is improved, and a γ-lactam structure is particularly preferable. An organic substance having a nitrate ester structure is preferable because it is easily decomposed and the conductive film after firing tends to have a low resistance.

  The structure containing nitrogen can be identified by ultraviolet-visible absorption spectroscopy, infrared absorption spectroscopy, Raman spectroscopy, nuclear magnetic resonance, electron spin resonance, mass spectrometry, X-ray analysis, and the like. .

  In addition to the structure containing nitrogen, the nonvolatile organic material of the present embodiment may have the following structure, for example. That is, non-volatile organic substances are polyethylene glycol (PEG), polypropylene glycol (PPG), polyimide, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyester, polycarbonate (PC), polyvinyl. Alcohol (PVA), polyvinyl butyral (PVB), polyacetal, polyarylate (PAR), polyamide (PA), polyamideimide (PAI), polyetherimide (PEI), polyphenylene ether (PPE), polyphenylene sulfide (PPS), poly Ether ketone (PEK), polyphthalamide (PPA), polyether nitrile (PEN), polybenzimidazole (PBI), polycarbodiimide, polysiro Sun, polymethacrylamide, nitrile rubber, acrylic rubber, polyethylene tetrafluoride, epoxy resin, phenol resin, melamine resin, urea resin, polymethyl methacrylate resin (PMMA), polybutene, polypentene, ethylene-propylene copolymer, ethylene -Butene-diene copolymer, polybutadiene, polyisoprene, ethylene-propylene-diene copolymer, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymer, polyethylene (PE), polychlorinated Vinyl (PVC), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), phenol novolac, benzocyclobutene, polyvinylphenol, polychloropyrene, polyoxymethylene, poly Sulfone (PSF), it may have polysulfide, silicone resins, aldose, cellulose, amylose, pullulan, dextrin, glucan, fructans, and a structure such as chitin. The non-volatile organic substance may have a structure obtained by modifying the functional group of these structures, may have a structure obtained by modifying these structures, or may have a copolymer structure of these structures. An organic substance having a skeleton selected from the group consisting of a polyethylene glycol structure, a polypropylene glycol structure, a polyacetal structure, a polybutene structure, and a polysulfide structure is preferable because it easily decomposes and does not easily leave a residue in the conductive film obtained after firing. An organic substance having a structure selected from the group consisting of a cellulose structure, an amylose structure, a pullulan structure, a dextrin structure, a glucan structure, a fructan structure, and a chitin structure is preferable because it tends to be excellent in particle dispersibility. In particular, organic materials having a cellulose structure and a pullulan structure can be suitably used because they are easily available.

  The phosphorus content of the non-volatile organic material of the present embodiment is preferably 5% by mass or less, more preferably 1% by mass or less, further preferably 0.5% by mass or less, and 0.0001 It is preferably at least mass%, more preferably at least 0.001 mass%, and even more preferably at least 0.005 mass%. When the phosphorus content of the nonvolatile organic substance is 5% by mass or less, the metal is hardly corroded by phosphorus and the conductivity is not easily lowered. If phosphorus content is 0.0001 mass% or more, the affinity of a non-volatile organic substance and a metal will improve, and the dispersibility of particle | grains will improve.

  The weight average molecular weight of the non-volatile organic material is preferably selected appropriately depending on the application method of the dispersion to the substrate. When the dispersion is used for reversal printing, the weight average molecular weight of the non-volatile organic material is preferably 500 or more, more preferably 800 or more, still more preferably 1,000 or more; 40,000 or less Preferably, it is 20,000 or less, more preferably 5,000 or less. When the dispersion is used for screen printing, it is preferably 1,000 or more, more preferably 10,000 or more, further preferably 50,000 or more, and 1,000,000 or less. Is preferably 500,000 or less, and more preferably 100,000 or less. When the dispersion is used for offset printing, it is preferably 500 or more, more preferably 1,000 or more, further preferably 5,000 or more, and preferably 100,000 or less. 50,000 or less, more preferably 20,000 or less. When the dispersion is used for letterpress printing, it is preferably 500 or more, more preferably 800 or more, further preferably 3,000 or more, and preferably 1,000,000 or less, 100 Is more preferably 10,000 or less, and even more preferably 10,000 or less.

  The weight average molecular weight of the non-volatile organic substance can be measured for various low molecular weight compounds by various mass spectrometry (MS). On the other hand, high molecular weight compounds can be measured by gel permeation chromatography (GPC). The standard for low molecular weight is less than 200, and the standard for high molecular weight is 100 or more.

The GPC measurement conditions are, for example, as follows when the organic substance is hydrophilic.
Data processing: Tosoh Corporation EcoSEC-WS
Pump: Waters Acquity H
RI detector: Tosoh Corporation RI8020
Oven: Tosoh Corporation CO8020
Column: TSKgel G3000PWXI + G2500PWXI (7.8 mm ID × 30 cm)
Column temperature: 40 ° C
Eluent: pH = 3.5 phosphoric acid aqueous solution Flow rate: 1.0 ml / min
Injection volume: 50 μl
Standard sample: Polyethylene oxide (Aldrich, PRODUCT No. 02393)

When organic substance is hydrophobic, it is as follows, for example.
Data processing: Tosoh Corporation EcoSEC-WS
Equipment: Tosoh Corporation EcoSEC
Column: TSKgel SuperHZM-M (4.6 mmID × 15 cm) + TSKgel SuperHZ2000 (4.6 mmID × 15 cm)
Temperature: 40 ° C
Eluent: THF
Flow rate: 0.35 ml / min
Detector: RI
Standard document: Polystyrene (Agilent company easy cal)

  The addition amount of the non-volatile organic substance is preferably 0.1 parts by mass or more, more preferably 5 parts by mass or more, further preferably 10 parts by mass or more, and 50 parts by mass with respect to 100 parts by mass of the particles. The content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less. If the addition amount of the nonvolatile organic substance is 0.1 parts by mass or more, the film formability is excellent, and if it is 5 parts by mass or more, the dispersibility of the particles tends to be excellent. If it is 10 parts by mass or more, the printability is excellent. There is a tendency. If it is 50 mass parts or less, it is easy to obtain a conductive film by baking.

  In the present embodiment, the nonvolatile organic substance includes an organic substance having a structure containing nitrogen (also referred to as “nitrogen-containing organic substance” in the present specification).

  The nitrogen-containing organic substance preferably has at least one selected from a nitrate ester structure, a nitro group, a cyano group, and a heterocyclic structure containing nitrogen. The nitrogen-containing organic substance preferably has an aldose structure.

  In the present embodiment, specifically, as the nitrogen-containing organic substance, specifically, at least one compound selected from the group consisting of nitrocellulose, polyvinyl pyrrolidone, and cyanoethyl pullulan can be suitably used. Nitrocellulose is particularly preferable because of its excellent particle dispersibility and low resistance of the conductive film after firing. The chemical structure of nitrocellulose is shown below.

  The nitrogen content of the nitrocellulose is preferably 6% by mass or more, more preferably 9% by mass or more, further preferably 11% by mass or more, preferably 13% by mass or less, and preferably 12.5% by mass or less. More preferred. When the nitrogen content of the nitrocellulose is 6% by mass or more, the dispersibility of the particles is improved. When the nitrogen content is 9% by mass or more, the organic matter is decomposed at a low temperature so that low temperature firing is possible. Since the residue hardly remains, the resistance of the conductive film after firing is further reduced. If it is 13% by mass or less, it can be handled safely, and if it is 12.5% by mass or less, it is easily dissolved in a solvent.

  The weight average molecular weight of the nitrogen-containing organic substance is not particularly limited, but is preferably 500 or more, more preferably 1,000 or more, and further preferably 2,000 or more; 1,000,000 or less. It is preferable that it is 500,000 or less, and it is further more preferable that it is 20,000 or less. If the weight average molecular weight is 500 or more, the dispersibility of the particles is improved, if it is 1,000 or more, the long-term storage stability is improved, and if it is 2,000 or more, it tends to have thixotropy and printability is improved. To do. If the weight average molecular weight is 1,000,000 or less, sufficient solubility can be obtained, if it is 500,000 or less, printable fluidity can be obtained, and if it is 20,000 or less, particles and Kneading becomes easy.

  The ratio of the nitrogen-containing organic substance in the nonvolatile organic substance is preferably 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and even 100% by mass. Good. If the ratio of the nitrogen-containing organic substance in the non-volatile organic substance is 50% by mass or more, it is preferable because it tends to be fired at low temperature.

  The dispersion of this embodiment contains a nonvolatile organic material including a nitrogen-containing organic material as an essential component. However, the dispersion of the present embodiment may further contain other components besides these. Examples of such other components include a surface energy adjusting agent, a dispersant, a plasticizer, and a solvent.

[Surface energy regulator]
The dispersion of the present embodiment may contain a surface energy adjusting agent in order to improve coatability. Thereby, when the dispersion is applied, the smoothness of the obtained coating film is improved, and thus a more uniform conductive film can be obtained.

  Specific examples of the surface energy modifier include trade names such as Triton X-45, Triton X-100, Triton X, Triton A-20, Triton X-15, Triton X-114, Triton X-405, Tween. # 20, Tween # 40, Tween # 60, Tween # 80, Tween # 85, Pluronic F-68, Pluronic F-127, Span 20, Span 40, Span 60, Span 80, Span 83, Span 85, etc .; AGC Seimi "Surflon S-211", "Surflon S-221", "Surflon S-231", "Surflon S-232", "Surflon S-233", "Surflon S-242", "Surflon S-" “243”, “Surflon S-611”, etc .; “NovecFC-4430”, “NovecFC-4432”, etc. manufactured by 3M; “Megafuck F-444”, “Megafuck F-558” manufactured by DIC, and the like. Among the surface energy modifiers, fluorine-containing surfactants are particularly preferable. “Surflon S-211”, “Surflon S-221”, “Surflon S-231”, “Surflon S-232”, “Surflon” manufactured by AGC Seimi Chemical “S-233”, “Surflon S-242”, “Surflon S-243”, and “Surflon S-611”; “NovecFC-4430” and “NovecFC-4432” manufactured by 3M; -444 "and" Megafuck F-558 "are preferably used. These may be used alone or in combination.

  The content of the surface energy adjusting agent in the dispersion of the present embodiment is not particularly limited, but is preferably 0.010% by mass or more, more preferably 0.10% by mass with respect to the total mass of the dispersion. is there. The content of the surface energy adjusting agent is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, with respect to the total mass of the dispersion. When the dispersion pair contains 0.010% by mass or more of the surface energy adjusting agent, when the dispersion is applied, the thickness of the obtained coating film tends to be uniform, and coating unevenness tends not to occur. On the other hand, in the conductive film obtained by baking the coating film, from the viewpoint of reducing the residue derived from the surface energy adjusting agent and obtaining good conductivity, the addition amount of the surface energy adjusting agent is 2.0% by mass or less. It is preferable that

[Dispersant]
The dispersant has a function of improving the dispersibility of the particles and preventing the particles from aggregating and settling. Therefore, the dispersant improves the storage stability of the dispersion and the smoothness and film thickness uniformity of the coating film when the dispersion is applied.

  Various commercially available dispersants can be used as the dispersant. Specific examples of the dispersant in the case where the solvent is water and a highly polar solvent include DISPERBYK-102, DISPERBYK-187, DISPERBYK-190, DISPERBYK-191, DISPERBYK-193, DISPERBYK-194N, DISPERBYK-199 manufactured by BYK Chemie. , DISPERBYK-2010, DISPERBYK-2012, DISPERBYK-2013, DISPERBYK-2015, DISPERBYK-2055, DISPERBYK-2060, DISPERBYK-2061, and DISPERBYK-2096.

  Specifically, as the dispersant when the solvent is a solvent system, DISPERBYK-102, DISPERBYK-103, DISPERBYK-109, DISPERBYK-110, DISPERBYK-111, DISPERBYK-118, DISPERBYK-140, DISPERBYK-145, DISPERBYK- 168, DISPERBYK-180, DISPERBYK-182, DISPERBYK-2000, DISPERBYK-2001, DISPERBYK-2009, DISPERBYK-2022, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2055, DISPERBYK-2055, 150 DISPER YK-2200, BYK-405, BYK-607, BYK-9076, and BYK-9077, and Dai-ichi Kogyo Seiyaku Co. PLYSURF M208F, and can be exemplified PLYSURF DBS like.

  Specific examples of the dispersant when no solvent is used include DISPERBYK-102, DISPERBYK-106, DISPERBYK-109, DISPERBYK-111, DISPERBYK-145, DISPERBYK-180, DISPERBYK-2008, DISPERBYK-2013, DISPERBYK-20. , DISPERBYK-2096, DISPERBYK-2152, DISPERBYK-2155, DISPERBYK-2200, BYK-9076, BYK-9077, and BYK-P105.

The content of the dispersant in the dispersion is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 2% by mass or more, and 20% by mass or less, based on the total mass of the dispersion. Is preferable, 15 mass% or less is more preferable, and 10 mass% or less is further more preferable.
Further, the content of the dispersant is preferably 0.1% by mass or more, more preferably 2% by mass or more, further preferably 10% by mass or more, and preferably 50% by mass or less, based on the total mass of the particles. The mass% or less is more preferable, and 30 mass% or less is more preferable. If the content of the dispersant with respect to the total mass of the particles is 0.1% by mass or more, sedimentation of the particles can be effectively prevented, and if the content is 2% by mass or more, good dispersibility can be obtained. If it is 10 mass% or more, good long-term storage stability can be obtained. If the content of the dispersant with respect to the total mass of the particles is 50% by mass or less, it is easy to obtain a conductive film by baking the coating film.

[Plasticizer]
The plasticizer can be added for the purpose of adjusting the viscosity and drying speed of the dispersion. Therefore, the printability of the dispersion can be improved. Although it does not restrict | limit especially as a plasticizer, A thing excellent in compatibility with another organic substance is preferable. As the plasticizer, phthalic acid esters, phosphoric acid esters, trimellitic acid esters, adipic acid esters and other fatty acid esters, polyesters, epoxies, sulfonic acid amides, and the like can be used. Specific examples of the plasticizer include triethyl citrate, acetyl triethyl citrate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diaryl phthalate, octyl phthalate, di-2-methoxyethyl phthalate, and phthalic acid. Bis (2-ethylhexyl), diisononyl phthalate, diundecyl phthalate, diamyl phthalate, dimethyl tartrate, diethyl tartrate, dibutyl tartrate, dioctyl tartrate, dimethyl adipate, diethyl adipate, dioctyl adipate, dimethyl sebacate, diethyl sebacate , Dibutyl sebacate, di-2-methoxyethyl sebacate, dioctyl sebacate, dimethyl maleate, diethyl maleate, dibutyl maleate, dioctyl maleate, diethylene glycol dimethyl ether, die Lenglycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol dioctyl ether, ethyl O-benzoylbenzoate, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, N-ethyltoluenesulfonic acid amide, triacetin, p-toluenesulfonic acid O -Cresyl, triethyl phosphate, triphenyl phosphate, tripropionine, castor oil, hydrogenated castor oil, polyethylene glycol-modified castor oil, polyethylene glycol and the like.

  As content of the plasticizer in a dispersion, 1 mass% or more is preferable with respect to the mass of a non-volatile organic substance, 10 mass% or more is more preferable, 20 mass% or more is further more preferable, 60 mass% or less is preferable, and 40 mass% or less is preferable. % Or less is more preferable, and 30% by mass or less is more preferable.

[solvent]
The dispersion of this embodiment may contain a solvent from the viewpoints of viscosity adjustment, coating property improvement, and the like, in addition to the nonvolatile organic material.

  As a solvent in the dispersion of this embodiment, various solvents can be used depending on the use of the dispersion. For example, it is preferable to use a high-boiling solvent in applications that require high smoothness, and it is preferable to use a low-boiling solvent in applications that require quick drying.

  The vapor pressure at 20 ° C. of the low boiling point solvent is preferably 20 Pa or more and 150 hPa or less, more preferably 100 Pa or more and 100 hPa or less, and further preferably 300 Pa or more and 20 hPa or less. In order to ensure the dispersion stability of the particles in the dispersion while maintaining a high volatilization rate of the solvent, the vapor pressure is preferably 150 hPa or less. On the other hand, the vapor pressure is preferably 20 Pa or more in order to obtain a drying speed at which cracks do not occur in the dispersion coating film.

  Specific examples of the low boiling point solvent include water, ethyl acetate, normal propyl acetate, isopropyl acetate, pentane, hexane, cyclohexane, methylcyclohexane, toluene, methyl ethyl ketone, methyl isobutyl ketone, dimethyl carbonate, methanol, ethanol, n -Propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3- Methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol N-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol. . Since the printing resin plate or blanket can be extended without extending the life, the solvent is preferably a hydrophilic solvent. Among them, a mixed solvent composed of water and a monoalcohol having 10 or less carbon atoms is preferable. More preferred. Among monoalcohols having 10 or less carbon atoms, dispersibility, volatility, and viscosity are particularly suitable, so ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, and t -At least one selected from the group consisting of butanol is more preferred. These monoalcohols may be used alone or in combination. If the carbon number of the monoalcohol is 10 or less, the dispersibility of the particles becomes better.

  The vapor pressure at 20 ° C. of the high boiling point solvent is preferably 0.010 Pa or more and less than 20 Pa, more preferably 0.05 Pa or more and less than 16 Pa, and still more preferably 0.1 Pa or more and less than 14 Pa. In order to maintain the smoothness of the dispersion coating film by the leveling effect, the vapor pressure is preferably less than 20 Pa. On the other hand, the vapor can be easily removed by a baking treatment described later, and the vapor can be prevented from being mixed with a solvent residue that could not be removed in the resulting conductive film. The pressure is preferably 0.010 Pa or more.

  Specific examples of the high boiling point solvent include propylene glycol monomethyl ether acetate, 3 methoxy-3-methyl-butyl acetate, ethoxyethyl propionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl. Ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether, ethylene glycol methyl ether, xylene, mesitylene, ethylbenzene, octane, nonane, decane, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2-pentanediol, 2-methylpentane-2,4 Diol, 2,5-hexanediol, 2,4-heptanediol, 2-ethylhexane-1,3-diol, diethylene glycol, dipropylene glycol, hexanediol, octanediol, triethylene glycol, tri1,2-propylene glycol And glycerol. Since the printing resin plate and the blanket do not swell and can extend the life, the solvent is preferably a hydrophilic solvent, and more preferably a polyhydric alcohol having 10 or less carbon atoms. These polyhydric alcohols may be used alone or in combination. If the carbon number of the polyhydric alcohol is 10 or less, the dispersibility of the particles becomes better.

  A mixture of the low boiling point solvent and the high boiling point solvent may be used.

  The amount of the solvent used is preferably 1% by mass or more and 99% by mass or less, and more preferably 10% by mass or more and 95% by mass or less with respect to the total mass of the dispersion. More preferably, it selects according to the application | coating method.

  For example, when the dispersion of this embodiment is applied to inkjet printing, the content of the solvent is preferably 40% by mass or more, and more preferably 60% by mass or more with respect to the total mass of the dispersion. 80% by mass or more, more preferably 99% by mass or less, more preferably 95% by mass or less, and further preferably 90% by mass or less. When the content of the solvent is 99% by mass or less, the thickness of the coating film is sufficiently increased, and a highly conductive wiring can be formed by baking treatment. When the content of the solvent is 40% by mass or more, the viscosity of the dispersant can be adjusted to a range suitable for inkjet printing, and when the content is 80% by mass or more, the eyes of the print head of the inkjet printing machine. Clogging is effectively prevented.

  When the dispersion of this embodiment is applied to screen printing, the content of the solvent is preferably 1% by mass or more, more preferably 10% by mass or more, and more preferably 20% by mass with respect to the total mass of the dispersion. % Or more, more preferably 60% by mass or less, more preferably 50% by mass or less, and further preferably 30% by mass or less.

  When the dispersion according to this embodiment is applied to reverse printing, the content of the solvent is preferably 40% by mass or more, more preferably 50% by mass or more, and 70% by mass with respect to the total mass of the dispersion. % Or more, more preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 85% by mass or less.

<Method for producing dispersion>
The dispersion can be prepared by mixing the above-mentioned particles, the non-volatile organic substance, and other components optionally blended at a predetermined ratio, respectively, and dispersing the mixture. The dispersion treatment is performed using an appropriate apparatus such as an ultrasonic method, a mixer method, a three-roll method, a two-roll method, an attritor, a Banbury mixer, a paint shaker, a kneader, a homogenizer, a ball mill, and a sand mill. Can do.

  When preparing the dispersion of the present embodiment, the dispersion obtained by appropriately setting the concentration of the above-mentioned particles and nonvolatile organic substances, and optionally mixed solvent, surface energy adjusting agent, and other components Body viscosity and surface energy can be adjusted.

The viscosity at 25 ° C. of the dispersion of this embodiment is preferably selected appropriately depending on the application. When the dispersion is used for screen printing in a region where the shear rate measured using a cone-plate type rotational viscometer is 1 × 10 ⁻¹ s ⁻¹ to 1 × 10 ² s ⁻¹ , the dispersion is used at 25 ° C. The viscosity in is preferably 1 cp or more, more preferably 10 cp or more, still more preferably 100 cp or more, preferably 1,000,000 cp or less, more preferably 100,000 cp or less. Preferably, it is 1,000 cp or less. When the dispersion is used for gravure offset printing, the viscosity of the dispersion at 25 ° C. is preferably 1 cp or more, more preferably 10 cp or more, further preferably 100 cp or more, and 100,000 cp or less. Is preferably 10,000 cp or less, and more preferably 1,000 cp or less. When the dispersion is used for reversal printing, the viscosity of the dispersion at 25 ° C. is preferably 0.1 cp or more, more preferably 1 cp or more, further preferably 5 cp or more, and 1,000 cp or less. It is preferably 100 cp or less, more preferably 50 cp or less. When the dispersion is used for letterpress printing, the viscosity of the dispersion at 25 ° C. is preferably 1 cp or more, more preferably 10 cp or more, further preferably 100 cp or more, and 100,000 cp or less. Preferably, it is 10,000 cp or less, more preferably 1,000 cp or less. If it is the viscosity of the said range, printability will become more favorable.

  Although there is no restriction | limiting in particular in the surface free energy in 25 degreeC of the dispersion of this embodiment, Preferably it is 40 mN / m or less, More preferably, it is 35 mN / m or less, More preferably, it is 30 mN / m or less. In reverse printing, from the viewpoint of wettability of the dispersion to the blanket, the surface free energy at 25 ° C. of the dispersion is preferably 40 mN / m or less. The surface free energy can be measured using a contact angle meter.

<< Printed Wiring Board Manufacturing Substrate and Method for Manufacturing the Same >>
The printed wiring board manufacturing substrate of this embodiment includes a base material and a film (hereinafter also referred to as “coating film”) formed on the base material. The film contains particles containing a metal and / or metal oxide, and a non-volatile organic substance, and the primary particle diameter of the particle is 5 nm or more and less than 100 nm, the non-volatile organic substance contains a nitrogen-containing organic substance, The non-volatile organic substance has a nitrogen content of 6% by mass to 55% by mass. The printed wiring board manufacturing substrate of the present embodiment can be manufactured, for example, by applying (printing) the dispersion of the present embodiment on a substrate and drying it. By printing the dispersion of this embodiment in a desired pattern, a printed wiring board having a desired conductive pattern can be manufactured by a subsequent baking process.

[Base material]
Examples of the base material include a resin base material, a glass base material, a silicon wafer, and a paper base material in addition to a general printed circuit board. Typical printed boards include paper phenol boards, paper epoxy boards, glass composite boards, glass epoxy boards, Teflon boards, alumina boards, low temperature co-fired ceramics (LTCC) boards, and the like.

  Examples of the resin base material include polyimide, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyester, polycarbonate (PC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), Polyacetal, polyarylate (PAR), polyamide (PA), polyamideimide (PAI), polyetherimide (PEI), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyether ketone (PEK), polyphthalamide (PPA) ), Polyether nitrile (PEN), polybenzimidazole (PBI), polycarbodiimide, polysiloxane, polymethacrylamide, nitrile rubber, acrylic rubber, polyethylene Rafluoride, epoxy resin, phenol resin, melamine resin, urea resin, polymethyl methacrylate resin (PMMA), polybutene, polypentene, ethylene-propylene copolymer, ethylene-butene-diene copolymer, polybutadiene, polyisoprene, ethylene- Propylene-diene copolymer, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymer, polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyether ether Ketone (PEEK), phenol novolac, benzocyclobutene, polyvinylphenol, polychloropyrene, polyoxymethylene, polysulfone (PSF), cycloolefin polymer (COP), and silicone Can be used consists substrate from butter, and the like. In particular, PET and PEN are available at low cost and are significant and preferred from a business perspective.

  The deflection temperature under load of the substrate is preferably 300 ° C. or less, more preferably 275 ° C. or less, and further preferably 250 ° C. or less. A base material having a deflection temperature under load of 300 ° C. or lower is available at low cost, and is significant and preferable from the viewpoint of business.

  The thickness of a base material can be 1 micrometer-10 mm, for example, Preferably it is 25 micrometers-250 micrometers. If the thickness of the base material is 250 μm or less, it is preferable because an electronic device to be manufactured can be reduced in weight, space-saving, and flexible.

[Pretreatment of substrate]
The substrate may be washed before forming the coating film. As the substrate cleaning method, for example, wet processing using a chemical solution; dry processing using corona discharge, plasma, UV, ozone, or the like can be used.

  When the formed coating film contains a solvent, the solvent is preferably removed from the coating film. The removal of the solvent can be performed by a method of leaving the coated film, for example, at 20 to 150 ° C., for example, for 1 minute to 2 hours. As a heating method in this case, for example, techniques such as hot air drying, infrared drying, and vacuum drying can be used.

[Coating film forming method]
The method for forming the coating film on the substrate as described above using the dispersion of the present embodiment is not particularly limited. For example, screen printing, spray coating, spin coating, slit coating, die coating, bar coating, knife coating, offset printing, reversal printing, flexographic printing, ink jet printing, dispenser printing, gravure direct printing, gravure offset printing, etc. Can do. Of these methods, reverse printing is preferable from the viewpoint that higher-definition patterning can be performed.

(Reverse printing)
The dispersion according to the present embodiment can be particularly preferably used for forming a patterned coating film on a substrate by reversal printing.

In the reverse printing method, first, a coating film having a uniform thickness is formed on the surface of a blanket.
The surface of the blanket is usually composed of silicone rubber. In reverse printing, it is necessary that the dispersion adheres well to the silicone rubber and a uniform coating film is formed. Therefore, it is desirable that the dispersion at 25 ° C. of the dispersion of this embodiment is 1 cp to 10,000 cp and the surface free energy at 25 ° C. is 40 mN / m or less.

  The surface of the blanket with the uniform dispersion coating film formed on the surface as described above is then pressed in contact with the relief printing plate, and the coating film formed on the blanket surface on the surface of the projection of the relief printing plate. A part is attached and transferred. Thereby, a desired printing pattern is formed on the coating film remaining on the surface of the blanket.

  Then, the blanket in this state is pressed against the surface of the substrate to be printed, and the patterned coating film remaining on the blanket is transferred to form a patterned coating film on the substrate to be printed. it can.

[Thickness of coating film]
The film thickness of the coating film can be selected according to the coating method.
For example, the film thickness of the coating film when using inkjet printing is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, as a value after removal of the solvent.

  When screen printing is used, the coating film thickness value after removal of the solvent is preferably 1 to 100 μm, and more preferably 10 to 50 μm.

  When using reverse printing, the coating film thickness after removal of the solvent is preferably 0.01 to 5 μm, more preferably 0.1 to 1 μm.

  The surface roughness (Ra) of the coating film is preferably 12 nm or less, more preferably 7 nm or less, and still more preferably 4 nm or less. If Ra is 12 nm or less, the coating film is in close contact with the removal plate during reverse printing, and sufficient removability tends to be obtained. If Ra is 7 nm or less, a flat film surface tends to be maintained even in the obtained conductive film. If Ra is 4 nm or less, uneven firing is very small and uniform electrical characteristics tend to be obtained.

  When the coating film formed as described above contains a solvent, the solvent is preferably removed from the coating film. The removal of the solvent can be performed by a method of leaving the coated film, for example, at 20 to 150 ° C., for example, for 1 minute to 2 hours. As a heating method in this case, for example, techniques such as hot air drying, infrared drying, and vacuum drying can be used.

[Coating film]
The coating film formed by applying the dispersion of the present embodiment includes particles containing a metal or metal oxide and a nonvolatile organic substance, and the nonvolatile organic substance in the coating film contains a nitrogen-containing organic substance, The nitrogen content of the nonvolatile organic material is 6% by mass or more.

  This film contains components other than the solvent among the components contained in the dispersion used for coating, preferably while maintaining its chemical structure and composition ratio. Therefore, as the constituent components of the membrane, those described above as the constituent components of the dispersion are preferably applied as they are.

  The coating film of the present embodiment is preferably bendable, that is, flexible without impairing its function. The bendable radius of curvature is preferably 1,000 mm or less, more preferably 500 mm or less, and even more preferably 100 mm or less. If it is 1,000 mm or less, it can be worn on a human torso, if it is 500 mm or less, it can be worn on a human leg, and if it is 100 mm or less, it can be worn on a human upper limb. In addition, it becomes possible to apply a roll-to-roll manufacturing method. The lower limit value of the radius of curvature can be set to 0.1 mm or more, for example.

<< Printed wiring board and manufacturing method thereof >>
By firing a printed wiring board manufacturing substrate having a coating film formed from the dispersion of the present embodiment, a conductive wiring having a conductive film can be formed.

[Baking]
A conductive film can be formed on the base material by heating the coating film formed as described above, followed by baking treatment.

  The firing method is not particularly limited as long as the particles contained in the coating film can be fused to form a sintered film of metal particles.

  Firing may be performed, for example, by a method using a heat medium such as a firing furnace, or may be performed using plasma, ultraviolet light, vacuum ultraviolet light, electron beam, infrared lamp annealing, flash lamp annealing, laser, or the like. Among these, it is preferable to perform by plasma treatment, flash lamp annealing treatment, or contact treatment with a heat medium.

  In particular, the flash lamp annealing process and the plasma process are characterized in that inorganic substances are heated strongly but organic substances are not heated so much. Therefore, the heating by these methods heats only the particles and does not damage the substrate. Therefore, an inexpensive but poorly heat-resistant resin such as PET can be used for the substrate, which is preferable. In particular, plasma treatment is more preferable because only the inorganic surface tends to be heated and damage to the substrate due to heat transfer is small.

(Conductive film formation by heat treatment)
Specifically, the heat treatment in this embodiment is a treatment in which a sample is heated by being brought into contact with a high-temperature medium.

  Although there is no particular designation for the high-temperature medium, for example, air, inert gas, reducing gas, liquid, metal, ceramic, resin, or the like can be used.

  The heat source for heating the medium is not particularly specified, and for example, a far infrared heater, a near infrared heater, a resistance heater, a microwave heater, a combustion heater, or the like can be used. As the far infrared heater, for example, a halogen heater, a quartz tube heater, a carbon heater, a sheathed heater, a metal heater or the like can be used. As the near-infrared heater, for example, a halogen heater can be used. As the resistance heater, for example, a metal heater or a ceramic heater can be used. As the heating element of the metal heater, for example, an alloy such as an iron-chromium-aluminum alloy or a nickel-chromium alloy and a metal such as platinum, molybdenum, tantalum, or tungsten can be used. As the heating element of the ceramic heater, for example, silicon carbide, molybdenum-silicite, carbon or the like can be used. The microwave heater is a heater that heats an object with an electromagnetic wave of about 100 kHz to 10 GHz. The combustion heater is a heater that heats an object with combustion heat when combustible substances such as heavy oil and gas are burned.

  The heat treatment temperature is preferably 180 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 120 ° C. or lower. When the heat treatment temperature is 180 ° C. or lower, a low-heat-resistant general-purpose resin substrate such as PEN or PET can be used. The heat treatment temperature is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and further preferably 50 ° C. or higher. If it is 20 degree | times or more, particle | grains will move in a coating film by a thermal vibration, and volume resistivity can be lowered | hung by particle | grains contacting. If it is 30 ° C. or higher, the movement of the particles in the coating film is accelerated due to the softening of the organic substance in the coating film, and when the organic substance is further softened, the particles settle due to the specific gravity difference between the particles and the organic substance, and the particle layer and the organic substance The volume resistivity can be further reduced because the insulating organic substance is less likely to enter between the particles. If it is 50 degreeC or more, since sintering of particle | grains will advance, volume resistance can be lowered | hung further.

  The heat treatment time is preferably 10 seconds or longer, more preferably 1 minute or longer, and further preferably 10 minutes or longer. If the heat treatment time is 10 seconds or longer, the resistance of the fired film can be lowered by bringing the particles into contact with each other. If the heat treatment time is 1 minute or longer, the resistance of the fired film is further lowered because the resistance of the particles themselves is reduced. In the case of 10 minutes or more, the sintering of the particles proceeds and the resistance of the fired film can be further reduced. Moreover, it is preferable from a viewpoint of heat damage reduction to a base material that the heat-firing time is 4 hours or less.

  The atmosphere during the heat treatment is not particularly specified, but an inert atmosphere is preferable, and a reducing atmosphere is more preferable. The atmosphere can be controlled, for example, by flowing an appropriate gas in the firing furnace. The inert atmosphere can be formed by flowing an inert gas. As the inert gas, rare gas such as vacuum, nitrogen, argon, helium can be used. The reducing atmosphere can be formed by flowing a reducing gas. Specifically, hydrogen, carbon monoxide, hydrogen sulfide, formaldehyde, or the like can be used as the reducing gas. Hydrogen is particularly preferable because it is not toxic. A reducing atmosphere can also be formed by mixing an inert gas and a reducing gas. For example, when an inert gas and hydrogen are mixed, the hydrogen content is preferably 0.1% by mass or more and 4% by mass or less. If the amount is less than 0.1% by mass, sufficient reducibility cannot be obtained, and if it is 4% by mass or less, it does not show flammability and can be used safely.

(Heating by infrared lamp annealing)
Specifically, the infrared lamp annealing is a method in which a sample is directly heated by irradiating the sample with infrared rays.

  The infrared source is not particularly specified, but for example, a halogen heater, a quartz tube heater, a carbon heater, a seed heater, a metal heater, or the like can be used.

  The atmosphere during the infrared lamp annealing is not particularly specified, but is preferably an inert atmosphere, and more preferably a reducing atmosphere. The atmosphere can be controlled, for example, by flowing an appropriate gas in the firing furnace. The inert atmosphere can be formed by flowing an inert gas. As the inert gas, rare gas such as vacuum, nitrogen, argon, helium can be used. The reducing atmosphere can be formed by flowing a reducing gas. Specifically, hydrogen, carbon monoxide, hydrogen sulfide, formaldehyde, or the like can be used as the reducing gas. Hydrogen is particularly preferable because it is not toxic. A reducing atmosphere can also be formed by mixing an inert gas and a reducing gas. For example, when an inert gas and hydrogen are mixed, the hydrogen content is preferably 0.1% by mass or more and 4% by mass or less. If the amount is less than 0.1% by mass, sufficient reducibility cannot be obtained, and if it is 4% by mass or less, it does not show flammability and can be used safely.

(Heating by plasma treatment)
Specifically, the plasma treatment is a treatment in which the sample is exposed to plasma by generating plasma in a space where the sample is placed.

  A method for generating plasma is not particularly specified. For example, a method using a DC arc discharge, a high-frequency electromagnetic field, a microwave, or the like can be used. In particular, a method using a microwave is preferable because plasma can be generated at a low temperature, and thermal damage to the substrate is small. The microwave specifically refers to an electromagnetic wave having a frequency of 300 MHz to 3 THz. The center frequency of the microwave is preferably 2 GHz or more and 4 GHz or less, and more preferably 2.4 GHz or more and 2.5 GHz or less.

  An apparatus for generating microwave plasma includes, for example, a microwave oscillator, a transmission circuit, an antenna, and a discharge vessel. In addition to these, a magnetic field generator may be further used as necessary. In this apparatus, plasma is generated in the discharge vessel. As the microwave oscillator, for example, a klystron, a magnetron, a gyrotron, or the like can be used. As the transmission circuit, for example, a rectangular waveguide, a circular waveguide, a coaxial line, or the like can be used. A power monitor and a dummy load that absorbs reflected power may be attached in the middle of the transmission circuit. As the structure of the apparatus, for example, it has a transmission line in the upper part and a discharge container in the lower part, the transmission line and the discharge container are connected via a quartz window, and the sample stage is in the lower part of the discharge container. It is preferable that it is installed.

  There is no specific designation for the microwave output, but an output of 100 W or more and 10 kW or less is preferable. The output of the microwave may be constant during the process or may be changed during the process.

  The temperature of the sample stage is not particularly specified, but is preferably 30 ° C. or higher and 150 ° C. or lower. If this temperature is 150 ° C. or lower, a general-purpose resin substrate having low heat resistance such as PET can be used as the base material. If it is 30 ° C. or higher, a dense conductive film can be obtained.

  The ambient atmosphere during the plasma treatment is not particularly specified, but a reducing atmosphere is preferable. The ambient atmosphere can be controlled, for example, by flowing an appropriate gas through the discharge vessel. The gas flow rate is not particularly specified, but is preferably 10 SCCM or more and 1,000 SCCM or less, more preferably 50 SCCM or more and 5,600 SCCM or less, and further preferably 100 SCCM or more and 400 SCCM or less. In particular, it is preferable to form a reducing atmosphere by flowing a mixed gas obtained by mixing a small amount of hydrogen with an inert gas. As the inert gas in the mixed gas, for example, nitrogen; a rare gas such as helium or argon can be used. The hydrogen content in the mixed gas is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 2% by mass or more and 6% by mass or less.

  The pressure in the discharge vessel may be atmospheric pressure or reduced pressure.

  The plasma treatment time is not particularly specified, but is preferably 10 seconds or longer and 30 minutes or shorter, more preferably 30 seconds or longer and 10 minutes or shorter, and further preferably 1 minute or longer and 5 minutes or shorter.

(Heating by flash lamp annealing)
The flash lamp annealing process is a process for heating a sample by irradiating the sample with light having a high energy density.

  As a light source used for the flash lamp annealing treatment, for example, a xenon lamp, a krypton lamp, or the like can be used.

  The wavelength of the light source is preferably in the visible light region because the coating film can be baked without causing thermal damage to the transparent resin substrate. The wavelength of the light source can be easily controlled through a color filter.

  The energy per pulse is not particularly specified, but is preferably 50 J or more and 3,000 J or less, more preferably 100 J or more and 2,000 J or less, and further preferably 150 J or more and 1,500 J or less. .

  The pulse time is not particularly specified, but is preferably 10 μsec or more and 100 msec or less, more preferably 50 μsec or more and 10 msec or less, and further preferably 100 μsec or more and 5 msec or less. Here, the pulse time refers to the time from the time when power is supplied to the lamp for pulsed light irradiation to the time when power supply to the lamp is stopped for turning off the pulsed light.

  The sample may be irradiated with pulsed light multiple times. The pulse interval is not particularly specified, but is preferably 10 μs or more and 1 second or less. Here, the pulse interval refers to the time from the time when power is applied to the lamp for pulsed light irradiation to the time when power is applied to the lamp for the next pulsed light irradiation.

  The temperature of the sample stage is not particularly specified, but is preferably 30 ° C. or higher and 150 ° C. or lower. If this temperature is 150 ° C. or lower, a general-purpose resin substrate having low heat resistance such as PET can be used as the base material. If it is 30 ° C. or higher, a dense conductive film can be obtained.

  During the flash lamp annealing process, a gas may be flowed into the container. In this case, since the sample is cooled by the gas flow, thermal damage to the substrate can be reduced.

  The ambient atmosphere during the flash lamp annealing treatment is not particularly specified, but a reducing atmosphere is preferable. The specific example of the reducing atmosphere and the gas flow rate are the same as those described above for the reducing atmosphere during plasma processing.

  After the flash lamp annealing treatment, a pressure treatment may be further performed. By pressurizing the sample after the flash lamp annealing treatment, the formed conductive film can be made denser, which is preferable. As a pressing method, for example, a roller press, a flat plate press, or the like can be used. In particular, a roller press is preferable because it is suitable for a large area press.

[Advantages of Printed Wiring Board Manufacturing Method Using Dispersion of Present Embodiment]
The dispersion according to the present embodiment can be formed by directly drawing the dispersion according to the present embodiment in a desired pattern on a substrate to form a patterned coating film and a conductive film. Therefore, productivity can be remarkably improved as compared with a conventional method using a photoresist.

  Furthermore, by using the dispersion of this embodiment, a conductive film laminate having a diameter of 7 inches or more, which was difficult to produce by conventional photolithography, can be easily produced.

[Conductive film]
The surface roughness (Ra) of the conductive film obtained by the above method is preferably 20 nm or less, more preferably 10 nm or less, and still more preferably 5 nm or less. If Ra is 20 nm or less, there are few places where the film thickness is locally thin, and defects due to disconnection can be reduced. If Ra is 10 nm or less, defects tend not to occur when another film or element is further laminated on the conductive film. If Ra is 5 nm or less, the crystallinity of another material further laminated on the conductive film can be improved, and thus, for example, it can be suitably used for forming an electrode of a thin film transistor.

  The resistivity of the conductive film of the present embodiment is preferably 200 μΩcm or less, more preferably 100 μΩcm or less, and further preferably 30 μΩcm or less.

  The conductive film of this embodiment is preferably bendable, that is, flexible without impairing its function. The bendable radius of curvature is preferably 1,000 mm or less, more preferably 500 mm or less, and even more preferably 100 mm or less. If it is 1,000 mm or less, it can be worn on a human torso, if it is 500 mm or less, it can be worn on a human leg, and if it is 100 mm or less, it can be worn on a human upper limb. In addition, the roll-to-roll manufacturing method can be applied. The lower limit value of the radius of curvature can be set to 0.1 mm or more, for example.

<< Application Example of Dispersion of this Embodiment >>
According to the dispersion of the present embodiment, a highly smooth conductive film having a miniaturized pattern can be obtained. Such a conductive film can be suitably used for, for example, a printed board, a flexible printed board, an electromagnetic wave shielding sheet, a semiconductor device (thin film transistor, diode, ferroelectric memory, etc.), a metal mesh transparent conductive film, and the like.

  The case where the dispersion of this embodiment is applied to a metal mesh transparent conductive film will be described. The metal mesh transparent conductive film refers to a metal substrate having a width of 50 μm or less formed on a transparent substrate in a mesh shape. This metal mesh transparent conductive film has a feature that its surface is electrically low resistance while being apparently transparent. Since a structure having a width of 50 μm or less is difficult to visually recognize, it seems as if the metal wiring of the metal mesh transparent conductive film does not exist on the substrate. Further, the region where the metal wiring does not exist (opening) transmits light. Therefore, the metal mesh transparent conductive film is visually recognized as a transparent body.

  The dispersion according to this embodiment can be suitably used as a material for forming wiring in the metal mesh transparent conductive film.

  When the dispersion according to the present embodiment is applied to the wiring formation of the metal mesh transparent conductive film, the ratio of the area of the opening of the metal mesh transparent conductive film to the entire surface area of the conductive film is 50 area% or more. It is preferably 80% by area or more, and more preferably 90% by area or more. If this ratio is 50 area% or more, the metal mesh transparent conductive film is recognized as a transparent body; if it is 80 area% or more, reflection of ambient light when the metal mesh transparent conductive film is used for a display. When the amount is less than 90% by area and the metal mesh transparent conductive film is used for a display, glare can be reduced. The width of the wiring is preferably 50 μm or less, more preferably 10 μm or less, and even more preferably 2 μm or less. If this width is 50 μm or less, the metal mesh transparent conductive film is recognized as a transparent body; if it is 10 μm or less, sufficient light transmittance and mesh density to be used for the transparent conductive film for touch panel can be obtained. Yes; if it is 2 μm or less, a highly uniform electric field can be formed on the mesh.

  The dispersion of the present embodiment is suitably used for forming a wiring of a metal mesh transparent conductive film in, for example, a common electrode of a liquid crystal display, an organic EL display, and electronic paper; a light extraction electrode of organic EL lighting; it can.

  Next, the case where the dispersion of this embodiment is applied to a thin film transistor will be described. A thin film transistor is an electronic device in which a gate electrode, a gate insulating film, a semiconductor, a source electrode, and a drain electrode are stacked. The dispersion of this embodiment can be suitably used as a material for forming a gate electrode, a source electrode, or a drain electrode. The distance between the source electrode and the drain electrode (channel length) is preferably 50 μm or less, more preferably 10 μm or less, and further preferably 2 μm or less. The smaller the channel length, the higher the operating frequency of the thin film transistor.

[Comparative Example 1]
In a mixed solvent composed of 800 g of water and 400 g of 1,2-propylene glycol (manufactured by Wako Pure Chemical Industries), 80 g of copper (II) acetate monohydrate (manufactured by Wako Pure Chemical Industries) is dissolved, and hydrazine (manufactured by Wako Pure Chemical Industries) is dissolved. After adding 24 g and stirring, it was separated into a supernatant and a precipitate using centrifugation. To 2.8 g of the resulting precipitate (1), 0.4 g of PEG-SH800 (trade name, manufactured by Aldrich) and 6.6 g of n-ethanol (manufactured by Wako Pure Chemical Industries) as a solvent are added and dispersed using a homogenizer. As a result, a dispersion of Comparative Example 1 containing copper (I) oxide particles was obtained.

[Comparative Example 2 and Examples 1 to 10]
The copper (I) oxidation was carried out in the same manner as in the above Comparative Example except that the type and amount of the organic substance added to 2.8 g of the precipitate (1) and the type and amount of the solvent were changed as shown in Table 1, respectively. The dispersion of Comparative Example 2 and Examples 1 to 10 each containing product particles was obtained.

[Measurement and evaluation method]
(1) Formation of coating film Using the dispersion obtained above, an L / S = 5 μm / 5 μm pattern was formed on a PEN film (manufactured by Teijin DuPont Films) by reversal printing according to the following procedure.

  The dispersion was uniformly applied to a PDMS smooth surface as a release surface of the blanket by a bar coater so as to have a dry film thickness of about 400 nm, and naturally dried for about 1 minute to obtain a coating film. Thereafter, the removal plate was pressed against the dispersion coating film on the blanket and then released to remove the unnecessary portion of the coating film. Subsequently, by pressing the PEN film onto the blanket, the pattern formed on the blanket was transferred onto the PEN film, and a printed wiring board manufacturing substrate was manufactured.

(2) Evaluation of fine printability The shape of the pattern obtained in (1) above was observed using an optical microscope and evaluated according to the following criteria.
When a pattern of L / S = 5 μm / 5 μm was formed: ◎ (good fine printability)
When L / S = 5 μm / 5 μm pattern is generally formed, but the edge of the pattern is uneven: ○
When there is a removal failure or transfer failure in the L / S = 5 μm / 5 μm pattern: × (fine printability failure)

(3) Measurement of nitrogen content of non-volatile organic substance Elemental analysis of the organic component of the coating film on the printed wiring board manufacturing substrate obtained in (1) above results in the nitrogen content (% by mass) of the non-volatile organic substance. Was measured.

(4) Formation of conductive film Using a far-infrared firing furnace, a process gas (3 volume% hydrogen, 97 volume% nitrogen) is introduced into the firing furnace at a flow rate of 5 L / min. The pattern obtained in (1) was heated to 180 ° C. Heating was performed for 10 hours.

(5) Volume resistivity of conductive film The volume resistivity of the conductive film obtained in (3) above was measured using a low resistivity meter Lorester GP manufactured by Mitsubishi Chemical.

  Various evaluation results of the dispersions of Comparative Examples 1 and 2 and Examples 1 to 10 are shown in Table 1.

In addition, the name in a table | surface points out the following compounds, respectively.
PEG-SH800: poly (ethylene glycol) methyl ether thiol (manufactured by Aldrich) having a number average molecular weight of 800
BYK-145: Disperbyk-145, a phosphate ester salt of a high molecular weight copolymer having a pigment affinity group (trade name, manufactured by Big Chemie)
BYK-118: Disperbyk-118, high polarity, linear polymer having various pigment affinity groups (trade name, manufactured by Big Chemie)
PVP: Polyvinylpyrrolidone (manufactured by Aldrich, product number PVP10-100G)
CEP: Cyanoethyl pullulan (Shin-Etsu Chemical Co., Ltd., Cyano Resin CR-S)
NC1: Isopropanol swollen product of nitrocellulose having a solid content of 70% by mass (product number SL-1 manufactured by Inabata Sangyo Co., Ltd.)
NC2: Isopropanol swelling product of nitrocellulose having a solid content of 70% by mass (product number DLX8-13, manufactured by Inabata Sangyo Co., Ltd.)
Castor oil: Castor oil (manufactured by Wako Pure Chemical Industries, product number 034-01586)
Dibutyl tartrate: L-(+)-dibutyl tartrate (manufactured by Tokyo Chemical Industry Co., Ltd., product number T0005)
Diamyl phthalate: Diamyl phthalate (manufactured by Tokyo Chemical Industry Co., Ltd., product number P0291)
Dioctyl maleate: bis (2-ethylhexyl) maleate (manufactured by Tokyo Chemical Industry Co., Ltd., product number M0011)
Ethanol: Ethanol (manufactured by Wako Pure Chemical Industries, product number 057-00456)
2-ME: 2-methoxyethanol (manufactured by Wako Pure Chemical Industries, product number 058-01106)

  The dispersion according to the present invention can obtain fine wiring by coating and baking treatment. Therefore, the dispersion is suitably used for producing printed wiring boards, electronic devices and the like.

Claims (5)

Particles comprising metal and / or metal oxide;
A dispersion containing non-volatile organic matter,
The primary particle diameter of the particles is 5 nm or more and less than 100 nm,
The non-volatile organic substance contains a nitrogen-containing organic substance, and the nitrogen content of the non-volatile organic substance is 6% by mass or more and 55% by mass or less.   The dispersion according to claim 1, wherein the nitrogen-containing organic substance has at least one selected from a nitrate ester structure, a nitro group, a cyano group, and a heterocyclic structure containing nitrogen.   The dispersion according to claim 1 or 2, wherein the nitrogen-containing organic substance has an aldose structure.   The dispersion according to claim 1, wherein the particles include particles composed of copper oxide. A printed wiring board manufacturing substrate having a base material and a film formed on the base material, wherein the film is
Particles comprising metal and / or metal oxide;
Containing non-volatile organic matter,
The primary particle diameter of the particles is 5 nm or more and less than 100 nm,
The non-volatile organic substance contains a nitrogen-containing organic substance, and the nitrogen content of the non-volatile organic substance is 6% by mass or more and 55% by mass or less.