JP2007194175A - Ink for conductor pattern, conductor pattern, wiring board, electro-optical device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink for a conductor pattern capable of manufacturing the conductor pattern in which there is less occurrence of cracks. <P>SOLUTION: This is composed of a colloid solution containing colloid particles in which a dispersant composed of a compound having at least one each of an amino group and a carboxyl group, and a conductive metal are at least contained, at least one kind or two kinds or more of non-ionic compounds out of tetraethylene glycol, polyethylene glycol, and propylene oxide-ethylene oxide block copolymer are contained in the colloid solution, and the content of the non-ionic compound exceeds 5 wt.% to the conductive metal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductor pattern ink, a conductor pattern, a wiring board, an electro-optical device, and an electronic apparatus, and particularly relates to an improvement of a conductor pattern ink.

  For example, a photolithography method is used for manufacturing a wiring used for an electronic circuit or an integrated circuit. In this lithography method, a photosensitive material called a resist is applied on a substrate on which a conductive film has been previously applied, a circuit pattern is irradiated and developed, and a conductive pattern is etched in accordance with the resist pattern to form a wiring composed of a conductor pattern. To form. This lithography method requires large-scale equipment such as a vacuum apparatus and a complicated process, and the material use efficiency is about several percent, and most of it must be discarded, and the manufacturing cost is high.

On the other hand, a method of forming a conductor pattern (wiring) by using a droplet discharge method in which a liquid material is discharged from a liquid discharge head in the form of droplets, a so-called inkjet method has been proposed (for example, see Patent Document 1). ). In this method, conductive pattern ink in which conductive fine particles are dispersed is directly applied to a substrate, and then heat treatment or laser irradiation is performed to evaporate the solvent and convert it into a conductive pattern. According to this method, there is an advantage that photolithography is not required, the process is greatly simplified, and the amount of raw materials used is reduced.
US Pat. No. 5,132,248

However, the conductor pattern manufactured with the conventional wiring pattern ink has a crack in the conductor pattern itself during the evaporation process of the solvent, which may increase the specific resistance of the conductor pattern or break the conductor pattern. . In particular, the occurrence of cracks has become remarkable as the thickness of the conductor pattern increases.
The causes of cracks are the rapid shrinkage of the conductor pattern during evaporation of the solvent, the shrinkage of the conductor pattern due to the removal of the dispersant adhering to the conductive fine particles, and the growth of metal particles due to heating during evaporation of the solvent. This is thought to be due to an increase in the gap in the conductor pattern accompanying the above.
In addition, voids increase in the conductor pattern as the metal fine particles grow, and if these voids appear on the surface of the conductor pattern, the flatness of the surface of the conductor pattern decreases, and so-called skin effect is not expressed. In addition, there is a problem that the high frequency characteristics are deteriorated.

  Further, when a conductive pattern having a relatively large thickness is formed by an ink jet method, the conductive pattern ink may be applied in an overlapping manner on the substrate. In this case, in order to prevent disconnection of the pattern and collapse of the shape, the previously disposed ink is dried (preliminary drying step), and then the next ink is disposed.

  In the above-described conductor pattern forming method, the application of the ink for the conductor pattern and the preliminary drying process are alternately repeated, so that the completed conductor pattern may have a laminated structure. In the conductor pattern having such a laminated structure, the specific resistance between the layers may increase, and the specific resistance of the entire conductor pattern may increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a conductor pattern ink capable of producing a conductor pattern with few cracks.
Another object of the present invention is to provide a conductor pattern that has few cracks, low specific resistance, and excellent high-frequency characteristics.
Furthermore, an object of the present invention is to provide a wiring board, an electro-optical device, and an electronic apparatus provided with a conductor pattern that has few occurrences of cracks, low specific resistance, and excellent high-frequency characteristics.

In order to achieve the above object, the present invention employs the following configuration.
The conductive pattern ink of the present invention comprises a colloidal solution comprising colloidal particles containing at least a dispersant composed of a compound having at least one amino group and a carboxyl group, and a conductive metal. The colloidal solution contains one or two or more nonionic compounds of tetraethylene glycol, polyethylene glycol, propylene oxide-ethylene oxide block copolymer, and the content of the nonionic compound is It is more than 5% by mass with respect to the conductive metal.
The conductive pattern ink of the present invention is prepared by dropping a conductive metal salt aqueous solution into an aqueous solution in which a dispersant and a reducing agent, each composed of a compound having at least one amino group and carboxyl group, are dissolved. In the colloidal solution, one or more nonionic compounds of tetraethylene glycol, polyethylene glycol, propylene oxide-ethylene oxide block copolymer are contained in the conductive metal. It is contained at a ratio of more than 5% by mass.
In the conductive pattern ink of the present invention, the content of the nonionic compound is preferably 7% by mass or more based on the conductive metal.
Furthermore, in the conductor pattern ink of the present invention, the reducing agent is preferably tannic acid.

In the conductive pattern ink, a nonionic compound is added to the colloidal solution in an amount of more than 5% by mass, preferably 7% by mass or more based on the conductive metal. Since this nonionic compound has a relatively high boiling point, in the process of forming the conductor pattern from the conductor pattern ink, the nonionic compound is evaporated or thermally decomposed after the dispersion medium of the colloidal solution is evaporated. For this reason, the state in which the nonionic compound wraps the colloidal particles continues for a long time, and rapid volume shrinkage is avoided and the growth of conductive metal particles is hindered.
Thereby, there is little possibility that a crack will generate | occur | produce in a conductor pattern, generation | occurrence | production of a disconnection is prevented, and reduction of a specific resistance is achieved.

  Next, the conductor pattern of the present invention is formed by the conductor pattern ink described above.

  According to the above conductor pattern, the conductive pattern ink described above is formed, the state in which the nonionic compound envelops the colloidal particles lasts for a long time, and rapid volume shrinkage is avoided and the conductive metal particles Since growth is hindered, there is little risk of cracking, breakage is prevented, and specific resistance is reduced.

Moreover, the conductor pattern of the present invention is the conductor pattern described above, wherein particles made of conductive metal are bonded to each other, and the particles are bonded without gaps on the surface of the conductor pattern, The pattern surface is glossy and has a specific resistance of less than 12 μΩcm.
In the conductor pattern of the present invention, the specific resistance is preferably 10 μΩcm or less.

According to the conductor pattern, particles made of conductive metal are bonded at least on the surface of the conductor pattern without gaps, and the surface of the conductor pattern is glossy, so that a so-called skin effect is expressed and high frequency characteristics are improved. .
Moreover, since the specific resistance of the conductor pattern is less than 12 μΩcm, the loss of current flowing through the conductor pattern is reduced. Moreover, the adhesiveness with respect to a base material is also favorable.

Next, the wiring board of the present invention is characterized by being provided with any of the conductor patterns described above.
In addition, an electro-optical device according to the present invention includes any one of the conductor patterns described above.
Furthermore, an electronic apparatus according to the present invention includes the electro-optical device described above.

  According to these inventions, since the high-frequency characteristics are improved and the conductor pattern having a low specific resistance is provided, the high-frequency characteristics are improved and energy saving is achieved.

ADVANTAGE OF THE INVENTION According to this invention, there is little possibility of a crack generation, the low specific resistance, and the conductor pattern ink which can manufacture the conductor pattern which is excellent also in the high frequency characteristic can be provided.
Further, according to the present invention, it is possible to provide a conductor pattern with less cracking, low specific resistance, and excellent high frequency characteristics.
Furthermore, according to the present invention, it is possible to provide a wiring board, an electro-optical device, and an electronic apparatus that can realize improvement in high-frequency characteristics and energy saving.

Embodiments of the present invention will be described with reference to the drawings.
"Ink for conductor pattern"
The conductive pattern ink of the present embodiment (hereinafter referred to as ink) includes colloidal particles containing at least a dispersant composed of a compound having at least one amino group and a carboxyl group and a conductive metal. It is roughly composed of a colloidal solution. Further, the colloidal solution constituting the conductor pattern ink contains a nonionic compound.
In addition, this ink is a colloidal solution prepared by dropping a conductive metal salt aqueous solution into an aqueous solution in which a dispersing agent and a reducing agent, each composed of a compound having at least one amino group and carboxyl group, are dissolved. The colloidal solution contains a nonionic compound.

The colloidal solution is a solution in which conductive metal particles (conductive metal) having a dispersant adsorbed on the surface adsorbed on the surface thereof are stably dispersed in an aqueous solution or a water-soluble solvent. By using the above compound as a dispersant, a colloid solution having high dispersibility can be obtained by a simple production method without specially controlling the atmosphere, temperature and stirring speed.
Since the above compound has an amino group, and this amino group has excellent adsorptivity to the surface of the conductive metal particles, the above compound can be efficiently adsorbed on the surface of the conductive metal particles, and can be added in a small amount. Colloidal particles with higher dispersibility can be obtained. Along with this, the number of carboxyl groups necessary for dispersion of colloidal particles can be reduced as compared with conventional dispersants, and a compound having an amino group and a carboxyl group should have at least one carboxyl group in the molecule. Sufficient dispersibility can be expressed. For this reason, the amount of dispersing agent to be added is extremely reduced, and an ink for a conductor pattern with a low content of organic matter affecting conductivity can be obtained without performing centrifugation or ultrafiltration.

  The above-mentioned compound constituting the dispersant is not particularly limited, but those having a small molecular weight and those having a plurality of carboxyl groups are preferable, for example, alanine, glycine, asparagine, aminobutyric acid, cysteic acid, cysteine, serine, glutamic acid, sarcosine, etc. Is preferred. Moreover, it is preferable that the carboxyl group of the said compound is a salt form. By using a salt, the dispersion stability due to the repulsive force of the carboxylate ion can be increased. In addition, solubility in water increases. It does not specifically limit as said salt, For example, sodium salt, potassium salt, lithium salt, ammonium salt etc. can be mentioned.

  The amount of the compound added is preferably 0.05 to 5 g with respect to 1 g of the conductive metal. If it is less than 0.05 g, the effect as a dispersant cannot be exhibited, and if it exceeds 5 g, the saturation amount of the dispersant is exceeded, so even if the amount added is increased, no further effect is obtained.

Further, the colloidal particles according to the present embodiment can be regarded as a solid content mainly composed of a conductive metal component and an organic component. The colloidal solution constituting the conductor pattern ink of this embodiment is composed of this solid content and solvent. Examples of the conductive metal constituting the solid content include gold, silver, copper, platinum, palladium, rhodium, ruthenium, iridium and osmium. Of these, silver, copper, platinum, and palladium are more preferable. These metals may be used independently and 2 or more types may be used together.
In particular, the conductor pattern ink of this embodiment is preferably composed of a mixed metal colloidal solution of silver and other metals. By using silver, the specific resistance of the conductor pattern formed using the colloidal solution is reduced. However, when using silver as an electronic material for a wiring board, it is necessary to consider the problem of migration. By using a mixed metal colloid solution composed of silver and other metals, migration becomes difficult to occur. Said other metals are said gold | metal | money, copper, platinum, palladium, rhodium, ruthenium, iridium, and osmium. Of these, copper, platinum, and palladium are preferable.

In the case of the mixed metal colloid solution as described above, the mass ratio of silver to other metal is preferably 99: 1 to 30:70 as the ratio of silver to the other metal in the colloid solution. When the ratio of silver exceeds 99% by mass, it becomes difficult to solve the migration property. On the other hand, if the silver ratio is less than 30% by mass, the conductivity of the resulting colloidal solution may be lowered. More preferably, it is 95: 5 to 40:60, and still more preferably 90:10 to 60:40.
Further, the content of the conductive metal in the colloidal solution is preferably 1 to 500 g / L. If it is less than 1 g / L, it is too thin and the number of times of recoating is increased in order to obtain a desired film thickness. If it exceeds 500 g / L, the viscosity increases so that it becomes difficult to handle.

Examples of the organic component constituting the colloidal particles (solid content) include compounds constituting the dispersant. In the conductor pattern ink of the present embodiment, the above compound can function as a dispersant, but this does not exclude the addition of other dispersants. As long as the effect of the conductive pattern ink is not impaired, another dispersant may be added. When another dispersant is added, the other dispersant also constitutes the organic component.
Other dispersing agents are not particularly limited as long as they are dissolved in a suitable solvent and exhibit a dispersing effect. For example, trisodium citrate, tripotassium citrate, trilithium citrate, disodium malate, tartaric acid Ionic compounds such as disodium and sodium glycolate; surfactants such as sodium dodecylbenzenesulfonate, sodium oleate, polyoxyethylene alkyl ether, perfluoroalkylethylene oxide adduct; gelatin, gum arabic, albumin, polyethyleneimine, Examples thereof include polymers such as polyvinyl celluloses and alkanethiols. These dispersing agents may be used independently and 2 or more types may be used together.

In addition, the nonionic compound is added to the conductive pattern ink of the present embodiment at a ratio of more than 5 mass% with respect to the conductive metal. As the nonionic compound, one or more of tetraethylene glycol, polyethylene glycol, and propylene oxide-ethylene oxide block copolymers are preferable.
Polyethylene glycol is polyethylene glycol # 200 (average molecular weight 200), polyethylene glycol # 300 (average molecular weight 300), polyethylene glycol # 400 (average molecular weight 400), polyethylene glycol # 600 (average molecular weight 600), polyethylene glycol # 1000 (average) Molecular weight 1000), polyethylene glycol # 1500 (average molecular weight 1500), polyethylene glycol # 1540 (average molecular weight 1540), polyethylene glycol # 2000 (average molecular weight 2000), or a mixture of two or more of them is preferable.
In the case of a propylene oxide-ethylene oxide block copolymer, those having an average molecular weight of 3000 or less are preferred.

By adding the above nonionic compound, a polymer chain exists between the colloidal particles, so that the approaching and aggregation of the colloidal particles can be suppressed, and the colloidal particles with higher concentration can be suppressed. Can be stably dispersed.
Moreover, since the colloid solution containing the nonionic compound has an appropriate viscosity, it is excellent in film formability.
Furthermore, since the nonionic compound has a relatively high boiling point, the nonionic compound evaporates after the dispersion medium (water, etc.) of the colloidal solution evaporates in the process of forming the conductor pattern from the ink for the conductor pattern. Or it decomposes oxidatively. For this reason, the state in which the nonionic compound wraps the colloidal particles continues for a long time, and rapid volume shrinkage is avoided and the growth of conductive metal particles is hindered.

When the addition rate of the nonionic compound is 5% by mass or less with respect to the conductive metal, in the process of forming the conductive pattern from the conductive pattern ink, the time required for evaporation or thermal decomposition of the nonionic compound is shortened. This is not preferable because a rapid volume shrinkage occurs during the formation of the conductor pattern and it becomes difficult to prevent the occurrence of cracks.
When the droplet discharge method is used, it is preferable that the addition rate of the nonionic compound exceeds 100% by mass with respect to the conductive metal because the viscosity of the ink itself increases and it may be difficult to apply the ink. Absent.
A more preferable range of the addition amount of the nonionic polymer is a range of 7 to 70% by mass with respect to the conductive metal, and a most preferable range is 10 to 50% by mass with respect to the conductive metal. % Or less.

  In the conductive pattern ink of the present embodiment, the form of the colloidal particles is not particularly limited. For example, particles in which an organic component is attached to the surface of the particles made of the conductive metal component, particles made of a conductive metal component And a particle whose surface is coated with an organic component, a particle obtained by uniformly mixing a conductive metal component and an organic component, and the like. Among these, particles having a conductive metal component as a core and a surface whose surface is coated with an organic component, and particles in which a metal component and an organic component are uniformly mixed are preferable.

  The amount of the organic component in the colloidal particles is preferably 1 to 30% by mass. If the amount is less than 1% by mass, the storage stability of the obtained conductor pattern ink tends to deteriorate, and if it exceeds 30% by mass, the specific resistance of the conductor pattern formed using the obtained conductor pattern ink increases. Tend. More preferably, it is 2-20 mass%.

  As a solvent used for the conductor pattern ink of the present embodiment, water and / or a water-soluble solvent is preferable. By using water and / or a water-soluble solvent as the solvent, the solvent odor does not become strong when the conductor pattern ink is dried or fired, and there is little adverse effect on the environment.

  Since the conductor pattern ink of this embodiment is composed of colloidal particles (solid content) and a solvent, the electrical conductivity can be 10 mS / cm or less. A conventional ink made of a metal colloid liquid reacts sensitively to the concentration of the electrolyte component present and aggregates and settles, and storage stability may be impaired. However, if the conductivity is 10 mS / cm or less, The influence can be sufficiently eliminated, and the deterioration of storage stability due to the increase in electrolyte concentration over time due to the dissolution of alkali in storage in glass containers and the dissolution of carbon dioxide in the air can be prevented. . Further, when the conductivity of the conductor pattern ink is 10 mS / cm or less, the dispersion stability of the colloidal solution is increased, so that it is easy to produce the conductor pattern ink having a high solid content concentration, and the volume can be reduced. Therefore, handling during distribution and transportation is easy. The high-concentration conductor pattern ink may be adjusted to an optimum concentration for use later by using an appropriate solvent.

In the conductive pattern ink of the present embodiment, the concentration of colloidal particles (solid content) is preferably 1 to 70% by mass. Here, the solid content can also be defined as the solid content remaining when most of the water is removed from the colloidal solution with silica gel or the like and then dried at a temperature of 70 ° C. or lower. Usually, this solid content consists of conductive metal particles, a residual dispersant, a residual reducing agent, and the like.
When the solid content is less than 1% by mass, the content of the conductive metal is too small, so when forming the conductor pattern using the obtained conductor pattern ink, many times in order to obtain the necessary thickness. This is industrially disadvantageous because it requires recoating. On the other hand, if the concentration of the solid content exceeds 70% by mass, the viscosity increases and it becomes difficult to handle, which is also industrially disadvantageous. More preferably, it is 3-50 mass%.

In the conductive pattern ink of the present embodiment, the loss on heating up to 100 to 500 ° C. by thermogravimetric analysis of the solid content is preferably 1 to 25% by mass. When the solid content is heated to 500 ° C., the organic components, the residual dispersant, the residual reducing agent and the like are oxidatively decomposed, and most of them are gasified and disappear. Since the amount of the residual dispersant and the residual reducing agent is considered to be small, it can be considered that the weight loss by heating up to 500 ° C. substantially corresponds to the amount of the organic component in the solid content.
The conductor pattern ink whose heat loss to 100 to 500 ° C. by thermogravimetric analysis of the solid content is 1 to 25% by mass is excellent in dispersion stability and deteriorates the conductivity of organic components and the like. Since the amount of the causative component is also appropriate, a conductor pattern having excellent conductivity can be formed.
When the solid weight loss by heating is less than 1% by mass, the amount of the organic component relative to the conductive metal component is small, so that sufficient dispersibility of the colloidal particles may not be obtained. Since the amount of the organic component relative to the conductive metal component is too large, the specific resistance of the obtained conductor pattern may be considerably deteriorated. When the amount of the organic component is large, the specific resistance can be improved to some extent by heating and baking after film formation to decompose and disappear the organic component, but this is not preferable because cracks and the like easily occur in the conductor pattern. More preferably, it is 1-10 mass%.

  In the conductive pattern ink of the present embodiment, the average particle size of the colloidal particles is preferably 1 to 400 nm. When the thickness is less than 1 nm, a good conductor pattern ink can be obtained, but in general, the production of such fine particles is expensive and impractical. On the other hand, if it exceeds 400 nm, the dispersion stability of the colloidal particles tends to change over time. More preferably, it is 1-70 nm.

  In addition to the nonionic compound, a film-forming aid may be added to the conductive pattern ink of this embodiment. Since the film-forming aid is compatible with the colloidal particles in the same manner as the nonionic compound, the film-forming aid is present uniformly between the colloidal particles and uniformly disperses the colloidal particles. Therefore, the conductive pattern ink in a solution state has an effect of improving storage stability. When a conductive pattern ink is applied to form a conductive pattern, the film-forming aid and the colloidal particles are familiar, so there is an effect of increasing the strength by forming a strong film, and the colloidal particles are uniformly conductive. Since it is dispersed in the pattern, it is possible to produce a uniform conductor pattern with little variation in specific resistance, and it is also possible to improve the adhesion to the substrate. That is, the film-forming aid can produce an effective film strength in a small amount and is less likely to impair good specific resistance.

The film-forming aid is not particularly limited as long as it dissolves in an appropriate solvent and forms an excellent thin film (conductor pattern) with colloidal particles. For example, polyurethane-based polyester resins, blocked isocyanates, and the like Examples thereof include resins, polyacrylate resins, polyacrylamide resins, polyether resins, and melamine resins.
When the solvent of the conductor pattern ink is water and / or a water-soluble agent, the film-forming aid is preferably an aqueous resin. The aqueous resin is not particularly limited. For example, forced emulsion resins such as aqueous polyurethane resins and aqueous polyester resins, cellulose resins, acrylate resins, polyvinyl alcohol resins, cellulose resins, aqueous polyaniline resins, blocks And polyurethane resins such as deisocyanate, and melamine resins. These aqueous resins may be used alone or in combination of two or more.

  Especially, as said aqueous resin, a polyurethane-type resin, a melamine-type resin, and a forced emulsion resin are preferable. When the polyurethane resin or melamine resin is used, it is preferable to use a blocked isocyanate or melamine resin and a polymer having an active hydrogen group in combination.

Among the aqueous resins, a blocked isocyanate using a polymer having an active hydrogen group in combination, a melamine resin using a polymer having an active hydrogen group, and a forced emulsion resin are more preferable. The aqueous resin composed of the resin as described above is extremely stable in a solution state, and a film having good water resistance can be easily obtained by heating, drying and curing.
The blocked isocyanate is not particularly limited, for example, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc., for example, blocked with oximes, alcohols, phenols, lactams, etc. Can be mentioned.
The melamine-based resin is not particularly limited, and examples thereof include alkyl group-type melamine, methylol group-type melamine, and imino group-type melamine. The forced emulsion resin is not particularly limited, and examples thereof include an aqueous polyurethane resin and an aqueous polyester resin.

The polymer having an active hydrogen group is not particularly limited, and examples thereof include polymers such as polyoxytetramethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, and polyvinyl alcohol having a hydroxyl group; polyethyleneimine, polyacrylamide, and the like. Examples thereof include a polymer having an amino group.
The amount of the film-forming aid added is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the solid content. If it exceeds 100 parts by mass, the conductivity may be deteriorated, and if it is less than 1 part by mass, the effect of adding a film-forming aid is not seen. More preferably, it is 1-50 mass parts.
The method for adding the film-forming aid to the conductive pattern ink is not particularly limited, and it may be added directly to the colloidal solution, or the film-forming aid is dissolved in a water-soluble solvent to prepare the film-forming aid solution. And may be added to the colloidal solution.

  A method for producing the conductor pattern ink of the present embodiment is not particularly limited, and examples thereof include a method of first preparing a solution containing colloidal particles and then cleaning the solution. The method for preparing the solution containing the colloidal particles is not particularly limited as long as it is a chemical reduction method. For example, a metal salt (metal ion) dispersed in a solution using a dispersant is used by any method. What is necessary is just to reduce.

  The metal salt is not particularly limited as long as it can be dissolved in an appropriate solvent and can be reduced by any means. For example, silver nitrate, silver sulfate, silver chloride, silver oxide, silver acetate, silver nitrite, silver chlorate Silver salts such as silver sulfide; gold salts such as chloroauric acid, potassium gold chloride and sodium chloride; platinum salts such as chloroplatinic acid, platinum chloride, platinum oxide and potassium chloroplatinate; palladium nitrate, palladium acetate, chloride Palladium salts such as palladium, palladium oxide and palladium sulfate, and other white metal salts can be used. These metal salts may be used independently and 2 or more types may be used together.

  The method for reducing the metal salt is not particularly limited, and may be reduced using a reducing agent, or may be reduced using light such as UV, electron beam, or thermal energy. The reducing agent is not particularly limited as long as it can be dissolved in a suitable solvent and reduce the metal salt. For example, amine compounds such as dimethylaminoethanol, methyldiethanolamine, triethanolamine, phenidone, and hydrazine. Hydrogen compounds such as sodium borohydride, hydrogen iodide and hydrogen gas; oxides such as carbon monoxide and sulfurous acid; ferrous sulfate, iron chloride, iron fumarate, iron lactate, iron oxalate, iron sulfide, acetic acid Low-valent metal salts such as tin, tin chloride, tin diphosphate, tin oxalate, tin oxide and tin sulfate; organic compounds such as sugars such as formaldehyde, hydroquinone, pyrogallol, tannin, tannic acid, salicylic acid and D-glucose Etc. Of these, tannic acid is preferred. When tannic acid is used as the reducing agent, the obtained colloid solution exhibits good dispersibility. For this reason, when tannic acid is used, the amount of the dispersant added can be further reduced, and a colloidal solution with a low organic matter content can be obtained. When using the above various reducing agents, the reduction reaction may be further promoted by applying light or heat.

  As a method for producing a solution containing colloidal particles using the metal salt, the dispersant and the reducing agent, for example, the metal salt is dissolved in pure water to prepare a metal salt solution, and the metal salt solution is gradually added. The method etc. which are dripped in the aqueous solution which the dispersing agent and the reducing agent melt | dissolved can be mentioned.

  In the solution containing the colloidal particles obtained as described above, in addition to the colloidal particles, a reducing agent residue and a residual dispersant are present, and the electrolyte concentration of the entire liquid is high. Since the liquid in such a state has high conductivity, the colloidal particles are agglomerated and easily settled. By washing the solution containing the colloidal particles to remove excess electrolyte, a colloidal solution having an electric conductivity of 10 mS / cm or less can be obtained.

  As a method for the above washing, for example, the liquid containing the obtained colloidal particles is allowed to stand for a certain period, and after removing the resulting supernatant liquid, pure water is added and stirred again, and the liquid is further allowed to stand for a certain period. A method of repeating the process of removing the produced supernatant several times, a method of performing centrifugation instead of the above-mentioned standing, a method of desalting with an ultrafiltration device, an ion exchange device or the like can be mentioned. Of these, the desalting method is preferred. Moreover, you may concentrate suitably the liquid which made the electrical conductivity 10 mS / cm or less by desalting etc.

  The method for preparing a mixed metal colloid solution composed of a plurality of conductive metals is not particularly limited. For example, in the case of preparing a mixed metal colloid solution composed of silver and other metals, the above method is used. Colloid liquid and metal colloid liquid of other metals are prepared separately and then mixed to form a mixed metal colloid solution, or a silver ion solution and other metal ion solution may be mixed and then reduced. .

  The nonionic compound may be added at any time after the formation of the colloidal particles. For example, in the washing step after the reduction reaction, an aqueous solution containing a nonionic compound adjusted to a predetermined concentration may be used instead of pure water to be added. Also, when cleaning several times, using an aqueous solution containing a nonionic compound only at the beginning, and then cleaning with pure water removes excess polymer other than adsorbed on the conductive metal particles, making it more effective. It is.

"Conductor pattern"
Next, the conductor pattern of this embodiment will be described. This conductor pattern is a thin-film conductor pattern formed by applying the ink onto a substrate and then heating, and is formed by bonding particles made of the conductive metal to each other. At least the conductor pattern The particles are bonded to each other without a gap on the surface, the surface of the conductor pattern is glossy, and the specific resistance is less than 12 μΩcm.

The conductor pattern of this embodiment is formed by applying the above ink on a substrate and then heating. The heating condition may be, for example, heating at 160 ° C. or higher for 20 minutes or longer. Under these conditions, the nonionic compound can be evaporated or thermally decomposed. Moreover, you may perform preheating in the range of 40 degreeC or more and 100 degrees C or less in order to evaporate a water | moisture content before a heating.
Although it does not specifically limit as said base material, For example, the board | substrate which consists of an alumina sintered compact, a green sheet, a phenol resin, a glass epoxy resin, glass etc .; Electronic equipment etc. in which the surface was formed with resin, ceramic, etc. are mentioned. it can. In addition, examples of the shape include a plate shape and a film shape.

  The method for applying ink onto the substrate is not particularly limited, and examples thereof include a droplet discharge method, a screen printing method, a bar coating method, a spin coating method, and a brush method.

The conductor pattern of the present embodiment is formed using an ink to which a nonionic compound is added. Since this nonionic compound has a relatively high boiling point, in the process of forming a conductor pattern from ink, a colloid solution After the dispersion medium evaporates, the nonionic compound evaporates or decomposes by heating. For this reason, the state in which the nonionic compound wraps the colloidal particles continues for a long time, and rapid volume shrinkage is avoided and the growth of conductive metal particles is hindered. By preventing the growth of the conductive metal particles in the process of forming the conductor pattern, the conductive metal particles in the conductor pattern are in a state of being closely bonded to each other. In particular, on the surface of the conductor pattern, the conductive metal particles are bonded together without a gap, and the surface of the conductor pattern is glossy. Thereby, the unevenness | corrugation in the conductor pattern surface decreases, and the flatness of the conductor pattern surface improves. As a result, a so-called skin effect is exhibited, and the high-frequency characteristics of the conductor pattern are improved.
In addition, since the conductive metal particles are in a state of being densely bonded to each other, there is little risk of cracks occurring in the conductor pattern, the occurrence of disconnection is prevented, and the specific resistance is reduced.

  The specific resistance of the conductor pattern is preferably less than 12 μΩcm, and more preferably 10 μΩcm or less. The specific resistance at this time refers to the specific resistance when heated and dried at 160 ° C. after applying the ink. When the specific resistance is 12 μΩcm or more, it is difficult to use for applications that require electrical conductivity, that is, electrodes formed on a circuit board.

Also, when forming the conductor pattern of this embodiment, after applying the ink by the above application method, preheating is performed to evaporate the dispersion medium such as water, and the ink is again applied on the preheated coating film. By repeatedly performing a process such as coating, a thick-film conductor pattern can be formed.
In the ink after evaporation of the dispersion medium such as water, nonionic compounds and colloidal particles remain, and since this nonionic compound has a relatively high viscosity, the coating film is not completely dried. There is no risk that the coating will be washed away. Accordingly, it is possible to apply the ink once, dry it, leave it for a long time, and then apply the ink again.
In addition, since the nonionic compound has a relatively high boiling point, there is no possibility that the ink will be deteriorated even if the ink is applied and dried and then left for a long time, so that the ink can be applied again and is homogeneous. A coating film can be formed. Thereby, there is no possibility that the conductor pattern itself has a multilayer structure, and there is no possibility that the specific resistance between the layers increases and the specific resistance of the entire conductor pattern increases.

By passing through the above steps, the conductor pattern of the present embodiment can be formed thicker than a conductor pattern formed by a conventional ink. More specifically, a film having a thickness of 5 μm or more can be formed. Since the conductor pattern of this embodiment is formed by the above ink, even if it is formed in a thick film of 5 μm or more, the occurrence of cracks is small, and a conductor pattern having a low specific resistance can be configured. The upper limit of the thickness is not particularly required, but if it is excessively thick, it may be difficult to remove the dispersion medium and the nonionic compound and the specific resistance may be increased. .
Furthermore, the conductor pattern of this embodiment has good adhesion to the substrate.

"Manufacturing example of wiring board"
Next, an example in which the above conductor pattern is applied to a wiring board will be described.
The wiring board of the present embodiment is configured to include a conductor pattern formed by applying the above ink. Hereafter, the manufacturing process of the wiring board of this embodiment is demonstrated sequentially.

FIG. 1 shows a substrate used when manufacturing the wiring substrate of the present embodiment. FIG. 1A is a schematic cross-sectional view of the substrate 10, and FIG. 1B is a schematic plan view of the substrate 10.
As shown in FIG. 1A, the substrate 10 has conductor patterns 12, 12... Made of Cu formed on both surfaces of a resin substrate such as polyimide, and the conductor patterns 12, 12. Through-hole vias 14 are formed to be connected to each other. As shown in FIG. 1B, which is a partial front view of the substrate 10 shown in FIG. 1A, each end of the conductor patterns 12, 12... On the substrate 10 side extends to the vicinity of the edge of the substrate 10. Has been issued.

  The conductor patterns 12, 12... Shown in FIGS. 1A and 1B are formed by applying the above-described conductor pattern ink by the droplet discharge method and drying and baking. When forming the conductor patterns 12..., The conductor pattern 12 formed by subjecting the conductor pattern forming surface of the substrate 10 to a roughening process except for a portion for forming a conductive pattern for electrolytic plating described later. , 12 and the substrate 10 can be improved in adhesion.

  Next, as shown in FIG. 2A, a portion not subjected to electrolytic plating is covered with a solder resist layer 18 so that a predetermined portion where electrolytic plating of the formed conductor pattern 12 is applied is exposed, and one surface of the substrate 10 is covered. An electroplating conductive pattern 16 is formed in the vicinity of the side edge by a droplet discharge method. As the ink ejected by the droplet ejection method, the above-described conductor pattern ink can be used in the same manner as the formation of the conductor pattern 12.

  As shown in FIG. 3A, which is a partial plan view of the substrate 10 shown in FIG. 2A, the formed electroplating conductive pattern 16 is formed by applying the electroplating conductive pattern 16 along the edge of the substrate 10. A bus line 16 a is formed, and a branch pattern 16 b extends from the bus line 16 a to each conductor pattern 12. The tip of the branch pattern 16b is connected to the end of the conductor pattern 12 as shown in FIG.

As shown in FIG. 2B, a metal film 26 is formed on the exposed portions of the conductor patterns 12 by electrolytic plating using the electroplating conductive pattern 16 formed in this way.
As the metal film 26 formed by such electrolytic plating, a metal film 26 made of a desired metal can be formed, but it is preferable to form a metal film 26 made of gold or nickel.
As shown in FIG. 2B, this electrolytic plating may be performed with the electroplating conductive pattern 16 exposed. This is because the metal film 26 formed on the electroplating conductive pattern 16 can be recovered and reused together with the electroplating conductive pattern 16 as described later.

By the way, the surface of the electroplating conductive pattern 16 formed by direct drawing on the one surface side of the substrate 10 by the droplet discharge method is an uneven surface with respect to the smooth surface of the substrate 10. It is estimated that Therefore, as shown in FIG. 2C, the electroplating conductive pattern 16 can be easily peeled off from the substrate surface together with the metal film 26 formed on the upper surface thereof.
As a means for peeling the electroplating conductive pattern 16, a means for peeling the adhesive tape attached to the electroplating conductive pattern 16 can be suitably used. When the adhesive tape is peeled off, the electroplating conductive pattern 16 having the metal film 22 formed on the upper surface and attached to the adhesive tape is peeled off.
Since the electroplating conductive pattern 16 having the peeled metal film 26 formed on the upper surface is attached to the adhesive tape, it can be recovered and reused.

The peeling of the electroplating conductive pattern 16 can be easily performed by making the substrate surface of the substrate 10 on which the electroplating conductive pattern 16 is formed a smooth surface. For this reason, when the substrate surface of the substrate 10 is roughened so as to improve the adhesion with the conductor patterns 12..., The portion of the substrate surface on which the electroplating conductive pattern 16 is formed is protected with a protective film or the like. Thus, it is preferable to prevent roughening and maintain the smooth surface state.
FIG. 3B shows a partial front view of the substrate surface from which the electroplating conductive pattern 16 has been peeled off. Although a part of the electroplating conductive pattern 16 remains at the end of the conductor pattern 12, it does not cause a problem as a conductor pattern of the wiring board.

The wiring board obtained in this way can be further processed as necessary to obtain a final product.
In such a wiring board manufacturing process, the conductor patterns 12 and the electroplating conductive pattern 16 are formed by a droplet discharge method, so that the formation and removal thereof can be easily performed, which is more than the conventional wiring board manufacturing process. The number of processes can be reduced.

Moreover, since it is not necessary to form the conductor pattern 12 and the electroplating conductive pattern 16 at the same time, the degree of freedom in designing the conductor pattern 12 can be improved.
1 to 3 described above, the resin substrate has been described as the substrate 10, but a silicon substrate or a ceramic substrate can be used as the substrate 10.
1 to 3, the substrate 10 having the conductor patterns 12 formed on both sides is used. However, the substrate 10 having the conductor patterns 12 formed only on one side can also be used.

"Manufacturing example of multilayer wiring board (wiring board)"
Next, another example in which the above conductor pattern is applied to a wiring board will be described.
The multilayer wiring board (wiring board) of this embodiment is provided with a conductor pattern formed by applying the above-described conductor pattern ink. Hereafter, the manufacturing process of the multilayer wiring board of this embodiment is demonstrated sequentially.

  First, a base body 30A as shown in FIG. The base body 30 </ b> A includes a substrate 31 and a conductive pattern 32 positioned on the substrate 31. Here, the substrate 31 is a flexible substrate made of polyimide. The substrate 31 has a tape-like shape, and for this reason, the substrate 31 is also called a tape substrate. In the present specification, the “base 30A” is a general term for the substrate 31 and one or more patterns or layers provided on the substrate 31.

Next, as shown in FIG. 4B, a conductive post (conductor pattern) 33 is provided by applying a conductive pattern ink to a part of the conductive pattern 32 by a droplet discharge method and drying by heating.
After forming the conductive post 33, as shown in FIGS. 4C and 4D, an insulating pattern 34 is provided by a droplet discharge method. The provided insulating pattern 34 surrounds the lower part of the side surface of the conductive post 33 and covers the conductive pattern 32. Here, as will be described below, the insulating pattern 34 includes two insulating sub-patterns 41 and 42 stacked on each other. The formation method of the insulating pattern 34 is as follows.

  First, by applying ink containing an insulating resin such as an acrylic resin by a droplet discharge method and drying, an insulating sub-pattern 41 is provided in a portion on the surface of the substrate 31 where the conductive pattern 32 is not present. (FIG. 4 (c)). Here, the thickness of the insulating sub-pattern 41 is set to substantially match the thickness of the conductive pattern 32. For this reason, after the insulating subpattern 41 is provided, the surface of the insulating subpattern 41 and the surface of the conductive pattern 32 are positioned at substantially the same level. The insulating sub pattern 41 includes an acrylic resin.

  Next, as in the case of the insulating subpattern 41, the insulating subpattern 42 is provided on the surface formed by the conductive pattern 32 and the insulating subpattern 41 by the droplet discharge method (FIG. 4D). Here, the insulating subpattern 42 is provided so as to cover the underlying conductive pattern 32 and the insulating subpattern 41 and to surround the lower portion of the side surface of the conductive post 33. The insulating subpattern 42 includes an acrylic resin.

Next, as shown in FIG. 4E, a plurality of dummy posts (conductor patterns) 35 are formed by applying the above-described conductor pattern ink onto the insulating pattern 44 by a droplet discharge method, followed by drying and baking. Is provided. Here, the plurality of dummy posts 35 are provided such that the upper portions of the plurality of dummy posts 35 and the upper portions of the conductive posts 33 are located at substantially the same level.
Since each dummy post 35 is formed by a droplet discharge method, the cross-sectional shape of each dummy post 35 is tapered. Specifically, the width of the bottom portion of the dummy post 35 is larger than the width of the upper portion of the dummy post 35.

  Next, as shown in FIG. 5A, each side surface of the dummy post 35 is surrounded on the insulating pattern 34 by a droplet discharge method, and the side surface of the conductive post 33 protruding on the insulating pattern 34 is surrounded. An insulating pattern 36 is provided. Here, the thickness of the insulating pattern 36 is set so that the upper portions of the plurality of dummy posts 35 and the upper portions of the conductive posts 33 are exposed from the insulating pattern 36.

  If the insulating pattern 36 is provided in this way, even if an attempt is made to extract the plurality of dummy posts 35 from the insulating pattern 36 by applying an external force in the vertical direction in the drawing to the plurality of dummy posts 35, the plurality of dummy posts 35 are insulated. The pattern 36 is not escaped. That is, each of the plurality of dummy posts 35 is fixed to the insulating pattern 36.

  Furthermore, as will be described later, the insulating pattern 36 is configured to contain an insulating material having good adhesion to the insulating pattern 34. Specifically, since the insulating pattern 34 is configured to contain acrylic resin, the insulating pattern 36 is similarly configured to contain acrylic resin. From this, the insulating pattern 36 and the insulating pattern 345 are in close contact with each other and fixed to each other.

Next, as shown in FIG. 5B, the conductive pattern ink is applied onto the insulating pattern 36 by a droplet discharge method, and then dried and baked, whereby each of the plurality of dummy posts 35 is obtained. A conductive pattern (conductor pattern) 37 connected to the upper portion and connected to the upper portion of the conductive post 33 is provided. In the present embodiment, the multilayer wiring board 30 is obtained from the base body 30A through such processes.
Here, the conductive pattern 37 contains a conductive metal. Since each of the plurality of dummy posts 35 contains the same type of conductive metal, the conductive pattern 37 and the plurality of dummy posts 35 are fixed in close contact with each other.

  As described above, since each of the plurality of dummy posts 35 is fixed to the insulating pattern 36, the conductive pattern 37 is also fixed to the insulating pattern 36. In addition, since the insulating pattern 36 is fixed to the insulating pattern 34, as a result, the conductive pattern 37 is also fixed to the underlying insulating pattern 34.

"Electro-optical device"
Next, a plasma display device will be described as an example of an electro-optical device.
FIG. 6 is an exploded perspective view of the plasma display device 500 of this embodiment.
The plasma display device 500 includes substrates 501 and 502 disposed opposite to each other, and a discharge display unit 510 formed therebetween.
The discharge display unit 510 is a collection of a plurality of discharge chambers 516. Among the plurality of discharge chambers 516, the three discharge chambers 516 of the red discharge chamber 516 (R), the green discharge chamber 516 (G), and the blue discharge chamber 516 (B) are arranged so as to form one pixel. Has been.

Address electrodes 511 are formed in stripes at predetermined intervals on the upper surface of the substrate 501, and a dielectric layer 519 is formed so as to cover the address electrodes 511 and the upper surface of the substrate 501. A partition wall 515 is formed on the dielectric layer 519 so as to be positioned between the address electrodes 511 and 511 and along the address electrodes 511. The barrier ribs 515 include barrier ribs adjacent to the left and right sides of the address electrode 511 in the width direction, and barrier ribs extending in a direction orthogonal to the address electrodes 511. A discharge chamber 516 is formed corresponding to a rectangular region partitioned by the partition 515.
In addition, a phosphor 517 is disposed inside a rectangular region defined by the partition 515. The phosphor 517 emits red, green, or blue fluorescence. The red phosphor 517 (R) is located at the bottom of the red discharge chamber 516 (R), and the bottom of the green discharge chamber 516 (G). Are arranged with a green phosphor 517 (G) and a blue phosphor 517 (B) at the bottom of the blue discharge chamber 516 (B).

On the other hand, a plurality of display electrodes 512 are formed in stripes at predetermined intervals on the substrate 502 in a direction orthogonal to the previous address electrodes 511. Further, a dielectric layer 513 and a protective film 514 made of MgO or the like are formed so as to cover them.
The substrate 501 and the substrate 502 are bonded to each other with the address electrodes 511... And the display electrodes 512.
The address electrode 511 and the display electrode 512 are connected to an AC power supply (not shown). By energizing each electrode, the phosphor 517 emits light in the discharge display portion 510, and color display is possible.

  In the present embodiment, the address electrode 511 and the display electrode 512 are each formed by the conductor pattern described above. Therefore, improvement of high frequency characteristics and energy saving based on the low specific resistance of the conductor pattern can be achieved.

Next, a liquid crystal device will be described as another example of the electro-optical device.
FIG. 7 shows a planar layout of signal electrodes and the like on the first substrate of the liquid crystal device according to this embodiment. The liquid crystal device according to this embodiment includes the first substrate, a second substrate (not shown) provided with scanning electrodes and the like, and a liquid crystal (not shown) sealed between the first substrate and the second substrate. )).

As shown in FIG. 7, a plurality of signal electrodes 310 are provided in a multiple matrix form in the pixel region 303 on the first substrate 300. In particular, each signal electrode 310 is composed of a plurality of pixel electrode portions 310a provided corresponding to each pixel and signal wiring portions 310b that connect them in a multiplex matrix, and extends in the Y direction. ing.
Reference numeral 350 denotes a liquid crystal driving circuit having a one-chip structure, and the liquid crystal driving circuit 350 and one end side (lower side in the figure) of the signal wiring portions 310b... Are connected via first routing wirings 331.
Further, reference numeral 340... Is a vertical conduction terminal, and the vertical conduction terminals 340... Are connected to terminals provided on a second substrate (not shown) by vertical conduction members 341. Further, the vertical conduction terminals 340... And the liquid crystal driving circuit 350 are connected via the second routing wirings 332.

In the present embodiment, the signal wiring portions 310b,..., The first routing wiring 331, and the second routing wiring 332, which are provided on the first substrate 300, are each formed of the above-described conductor pattern. Therefore, improvement of high frequency characteristics and energy saving based on the low specific resistance of the conductor pattern can be achieved.
The devices to which the present invention can be applied are not limited to these electro-optical devices, but can be applied to other device manufacturing such as semiconductor mounting wiring.

"Electronics"
Next, specific examples of electronic devices will be described.
FIG. 8A is a perspective view showing an example of a mobile phone. 8A, reference numeral 600 denotes a mobile phone main body, and reference numeral 601 denotes a liquid crystal display unit including the liquid crystal device shown in FIG.
FIG. 8B is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer. 8B, reference numeral 700 denotes an information processing apparatus, reference numeral 701 denotes an input unit such as a keyboard, reference numeral 703 denotes an information processing body, and reference numeral 702 denotes a liquid crystal display unit including the liquid crystal device shown in FIG.
FIG. 8C is a perspective view showing an example of a wristwatch type electronic device. In FIG. 8C, reference numeral 800 denotes a watch body, and reference numeral 801 denotes a liquid crystal display unit including the liquid crystal device shown in FIG.
Since the electronic apparatus shown in FIGS. 8A to 8C includes the liquid crystal device according to the above-described embodiment, the quality can be improved and the cost can be reduced.
In addition, although the electronic device of this embodiment shall be provided with a liquid crystal device, it can also be set as the electronic device provided with other electro-optical devices, such as an organic electroluminescent display apparatus and a plasma type display apparatus.

Hereinafter, the present invention will be described specifically by way of examples.
"Experiment 1"
(Manufacture of ink for conductor pattern of Example)
Synthetic glycine of silver colloidal liquid (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) 0.44 g and tannic acid (manufactured by Wako Pure Chemical Industries, Ltd., chemical) 0.5 g are dissolved in 90 mL of ion-exchanged water and hydroxylated. After adjusting the pH to 7 with an aqueous sodium solution (manufactured by Wako Pure Chemical Industries, Ltd., a reagent special grade adjusted to an appropriate concentration with ion-exchanged water), ion-exchanged water was added to make the total volume 128 mL. Next, while stirring with a magnetic stirrer at room temperature, 2 mL of an aqueous solution containing 1 g of silver nitrate (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade) was added dropwise to prepare a colloidal aqueous solution having a metal content of about 5 g / L. At this time, the amount of glycine with respect to 1 g of silver is 0.69 g.
Then, by adding polyethylene glycol # 300 (hereinafter referred to as PEG) to the colloidal solution at a ratio of 7 to 100% by mass with respect to the mass of silver, the conductor pattern ink of this example was obtained. Manufactured.

(Manufacture of conductive pattern ink of comparative example)
A conductor pattern ink of a comparative example was manufactured in the same manner as in the above example except that the amount of PEG added was 0 to 5% by mass with respect to the mass of silver.

(Formation and evaluation of conductor pattern)
The conductive pattern inks of the obtained examples and comparative examples were applied on a glass substrate by a droplet discharge method, heated at 180 ° C. for 30 minutes and dried to have a length of 30 mm, a width of 50 μm, and a thickness of 5 μm. A conductor pattern was formed. In forming the conductor pattern, the ink application and drying steps were repeated many times until the thickness of the conductor pattern reached 5 μm.
Regarding the formed conductor pattern, the state of occurrence of cracks was confirmed and the specific resistance was measured. Table 1 shows the occurrence of cracks and the measurement results of specific resistance. FIG. 9 shows the relationship between specific resistance and the amount of PEG added. In addition, about the comparative example, since generation | occurrence | production of a crack was estimated | forecasted and it was estimated that the measurement of specific resistance became difficult, the 0.5-micrometer-thick conductor pattern was manufactured and the specific resistance was measured.

As shown in Table 1, the conductor pattern manufactured with the conductor pattern ink of the comparative example was in a situation where many cracks were generated and the conductor pattern itself was liable to collapse despite the thin thickness of 0.5 μm. . On the other hand, although the conductor pattern manufactured with the ink for the conductor pattern of the example has a thickness of 5 μm, which is 10 times the thickness of the comparative example, although some cracks are observed, it is clearly compared. It was less than in the case of the example, and the conductor pattern did not collapse. Furthermore, in the case where PEG was added in an amount of 10% by mass or more with respect to silver, almost no cracks were observed, and an extremely good conductor pattern was obtained.
Moreover, the conductor pattern manufactured with the ink for conductor patterns of an Example had the smooth surface, and the metal luster was seen. On the other hand, in the comparative example, the conductor pattern surface was rough and no metallic luster was observed.

  Next, as shown in Table 1 and FIG. 9, as the amount of PEG added increases, the specific resistance of the conductor pattern decreases, and the tendency of the decrease in specific resistance is between the occurrence of cracks. Correlation was seen. In particular, when the addition amount of PEG is 0% by mass or 5% by mass and the addition amount is 10% by mass or more, it can be seen that the specific resistance is halved from 12 μΩcm to about 6 μΩcm.

FIG. 10 shows a cross-sectional SEM image of a conductor pattern of a comparative example manufactured with an ink having an addition amount of PEG of 0 mass%. Further, FIG. 11 shows a cross-sectional SEM image of the conductor pattern of the example manufactured with the ink having the addition amount of PEG of 20% by mass.
As shown in FIG. 10, it can be seen that in the conductor pattern of the comparative example, silver particles are grown and the particle size is relatively large, and there are many gaps between the silver particles. In the comparative example, it is considered that the specific resistance has increased because there are many gaps between silver particles.

  On the other hand, it can be seen that the conductor pattern of the example shown in FIG. 11 has a grain size that is about one-third smaller than that of the comparative example without the silver particles growing. In addition, although there is a gap between the silver particles, the volume of the gap is small compared to the comparative example, and the density of the conductor pattern itself is considered to be higher than that of the comparative example, thereby reducing the specific resistance. It is thought that. Furthermore, the surface of the conductor pattern of an Example does not see the clearance gap between silver particles, but the surface is substantially flat. It is considered that the metallic luster was observed on the surface of the conductor pattern of the example due to the shape of this surface. When the surface of the conductor pattern is such a flat surface, it is predicted that the skin effect is developed and the high-frequency characteristics are improved particularly when used in high-frequency applications.

"Experimental example 2"
The conductor pattern inks of Examples and Comparative Examples manufactured in Experimental Example 1 were applied onto a glass substrate by a droplet discharge method, dried by heating at 180 ° C. for 30 minutes, and 30 mm in length and 50 μm in width. A conductor pattern having a thickness of 0.5 to 50 μm was formed.
In forming the conductor pattern, the ink application and drying steps were repeated many times until a crack occurred in the conductor pattern, thereby forming conductor patterns having different thicknesses for each ink. If a crack occurred in one place in the conductor pattern, the ink application and drying steps were finished, and the thickness of the conductor pattern before the crack was generated was measured. However, the formation thickness of the conductor pattern was set to 50 μm at the maximum.
FIG. 12 and Table 2 show the relationship between the amount of PEG added and the thickness of the conductor pattern at the time before cracks occur.

  As shown in FIG. 12 and Table 2, it can be seen that the thickness of the crack-free conductor pattern increases as the amount of PEG added increases. In addition, when the addition amount of PEG is 20% by mass or more, the thickness of the crack-free conductor pattern seems to be saturated at 50 μm, but this is because the formation thickness of the conductor pattern is 50 μm at the maximum. Further, if the ink application is further continued, it is considered that a film having a thickness of 50 μm or more can be formed.

It is a figure for demonstrating the first stage process of the manufacturing process of the wiring board which is embodiment of this invention, Comprising: (a) is a cross-sectional schematic diagram of a board | substrate, (b) is a partial top view of a board | substrate. It is a cross-sectional schematic diagram for demonstrating the latter process of the manufacturing process of the wiring board which is embodiment of this invention. It is a figure for demonstrating the latter process of the manufacturing process of the wiring board which is embodiment of this invention, Comprising: (a) is a partial top view corresponding to the wiring board shown to Fig.2 (a), (b) FIG. 3 is a partial front view corresponding to the wiring board shown in FIG. It is process drawing explaining the manufacturing process of the multilayer wiring board which is embodiment of this invention. It is process drawing explaining the manufacturing process of the multilayer wiring board which is embodiment of this invention. FIG. 4 is an exploded perspective view showing an example in which the electro-optical device of the invention is applied to a plasma display device. FIG. 6 is a plan view showing an example in which the electro-optical device of the invention is applied to a liquid crystal device. (A) is a figure which shows the example which applied the electronic device of this invention to the mobile telephone, (b) is a figure which shows the example applied to the portable information processing apparatus, (c) is applied to a wristwatch type electronic device FIG. It is a graph which shows the relationship between the addition amount of PEG, and the specific resistance of a conductor pattern. It is a cross-sectional SEM image of the conductor pattern of a comparative example. It is a cross-sectional SEM image of the conductor pattern of an Example. It is a graph which shows the relationship between the addition amount of PEG, and the thickness of the conductor pattern in the time before a crack generate | occur | produces.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Conductor pattern, 30 ... Wiring board, 33 ... Conductive post (conductor pattern), 35 ... Dummy post (conductor pattern), 500 ... Plasma type display apparatus (electro-optical apparatus), 600 ... Mobile phone main body (electronic device), 700: Information processing device (electronic device), 800: Watch body (electronic device)

Claims (10)

  It comprises a colloidal solution comprising colloidal particles comprising at least a dispersing agent comprising a compound having at least one amino group and a carboxyl group and a conductive metal, and the colloidal solution includes tetraethylene glycol, Any one or two or more kinds of nonionic compounds among polyethylene glycol and propylene oxide-ethylene oxide block copolymers are included, and the content of the nonionic compounds is 5 mass relative to the conductive metal. Conductor pattern ink, characterized in that it is over%. A colloidal solution prepared by dropping a conductive metal salt aqueous solution into an aqueous solution in which a dispersant and a reducing agent, each of which has at least one amino group and a carboxyl group, are dissolved;
In the colloidal solution, one or two or more nonionic compounds of tetraethylene glycol, polyethylene glycol, propylene oxide-ethylene oxide block copolymer are contained in a proportion of more than 5% by mass with respect to the conductive metal. Conductor pattern ink, characterized in that it is contained.   3. The conductive pattern ink according to claim 1, wherein the content of the nonionic compound is 7% by mass or more based on the conductive metal.   The conductive pattern ink according to claim 2, wherein the reducing agent is tannic acid.   A conductor pattern formed with the conductor pattern ink according to claim 1.   Particles made of conductive metal are bonded to each other, the particles are bonded to each other on the surface of the conductor pattern without gaps, the surface of the conductor pattern is glossy, and the specific resistance is less than 12 μΩcm. The conductor pattern according to claim 5.   7. The conductor pattern according to claim 5, wherein the specific resistance is 10 [mu] [Omega] cm or less.   A wiring board comprising the conductor pattern according to claim 5.   An electro-optical device comprising the conductor pattern according to claim 5. An electronic apparatus comprising the electro-optical device according to claim 9.

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