WO2016002881A1

WO2016002881A1 - Fine particle dispersion liquid, wiring pattern and method for forming wiring pattern

Info

Publication number: WO2016002881A1
Application number: PCT/JP2015/069133
Authority: WO
Inventors: 潤深井; 坂上　恵; 彰馬中川
Original assignee: 国立大学法人九州大学
Priority date: 2014-07-02
Filing date: 2015-07-02
Publication date: 2016-01-07
Also published as: JPWO2016002881A1

Abstract

This fine particle dispersion liquid contains fine particles and a surface conditioning agent which has a main chain having a repeating unit that contains a siloxane bond, and which has a hydrophilic group in a side chain and/or at an end of the main chain. A fine wiring pattern is able to be formed with a uniform line width if this fine particle dispersion liquid is used therefor.

Description

Fine particle dispersion, wiring pattern, and method of forming wiring pattern

The present invention relates to a fine particle dispersion, a wiring pattern, and a method for forming a wiring pattern.

In recent years, a new technology called printable electronics, in which conductive fine particle dispersions are directly drawn to form conductive circuit patterns using printing techniques such as the inkjet method, has attracted attention. Is expected to be possible.
Until now, in the manufacturing process of various electronic parts such as semiconductors, fine metal wiring is formed by forming a metal thin film by sputtering or vacuum vapor deposition using a vacuum device, and then removing unnecessary portions by etching or the like. The focus was on the vacuum / photolithographic process and the etching process to be formed. However, since this method requires a large-scale apparatus, the apparatus introduction cost and the manufacturing cost increase. Furthermore, there are problems such as a large environmental load because there are many emissions such as organic solvents, cleaning water, and etchant waste liquid. For this reason, since there are few manufacturing processes and only a small amount of waste is required, it is required to realize fine wiring patterns and electrode formation in the printable electronics technology that can save resources, save energy, and produce products at low cost.
In addition, the wiring pattern by this printable electronics technology is expected to be applied to various devices. Various printing methods such as ink jet method, gravure printing, nanoimprint method, etc. using ink in which metal or metal oxide nanoparticles are dispersed. And is expected to be applied to fine wiring, electrode formation, and transparent conductive films. As application products, use of auxiliary wiring and electrodes for touch panels, organic electroluminescence (organic EL) displays, lighting, and the like, and electrode formation of thin film transistors has been studied. For example, when used as an electrode of an organic transistor, if the film shape is not uniform, the resistance value cannot be made sufficiently small, or the resistance may vary, and an organic film formed on the upper part of the film may be formed. There is a problem that a uniform film cannot be formed and sufficient reproducibility of characteristics cannot be obtained. Therefore, in the formation of wiring and electrodes using these nanoparticles, development of a technique for flattening and thinning the wiring shape is strongly demanded.

By the way, the stain that occurs after the coffee spilled on the desk dries is called coffee stain. This is because the drying speed of the outer peripheral portion of the droplet is high, so that the solute concentration at the outer peripheral portion of the coffee droplet increases during the evaporation process, and the solute accumulates in a ring shape. Similarly, when the polymer solution droplet dropped on the substrate evaporates, a solute is deposited particularly near the contact line, and a ring-shaped thin film is formed. The formation of such a ring-shaped thin film is considered to occur when a wiring pattern is formed by a printable electronics technology, and this phenomenon hinders flattening and miniaturization of the wiring shape. There are some reports on the cause of this ring formation.

For example, Non-Patent Documents 1 to 3 report the results of observing the behavior of fine particles in the evaporation process of macro droplets having a droplet diameter of 1 mm or more using aqueous droplets in which fine particles are suspended. This document reports that the reason why the ring is formed is that the contact line is fixed during the evaporation process, and that the evaporation rate in the vicinity of the contact line is larger than the central part of the droplet. For this reason, it has been reported that a flow that compensates for the solvent lost near the contact line occurs inside the droplet, and the solute is carried in the direction of the contact line, so that the concentration of the solute near the contact line increases and a ring is formed. . In the same document, a one-dimensional mass transfer model in which solutes are deposited in a ring shape is proposed. In this model, it is necessary to give an evaporation rate distribution as a boundary value problem of the droplet free surface. Here, it is assumed that the boundary value problem of the droplet free surface is the same as the boundary value problem of electromagnetics in a capacitor composed of two wedge-shaped flat plates. It is given as an exponential function determined by the angle.

In Non-Patent Document 4, the evaporation rate distribution of the free surface estimated by the heat conduction analysis by the two-dimensional finite element method is added to the one-dimensional mass transfer model for the influence of the substrate temperature, solute concentration and droplet volume on the thin film formation. We conduct theoretical analysis of thin film formation and compare it with experiments. In this document, a rigorous theoretical analysis is performed using a two-dimensional mass transfer model that takes into account flow, heat transfer, and mass transfer, and is compared with experiments. According to this, the temperature gradient generated inside the droplet due to the substrate temperature and the latent heat of vaporization is different between the droplet center near the droplet height and the contact line at the low height. In order to produce a distribution, an evaporation rate distribution is produced on the droplet surface. As the substrate temperature increases, the advection speed toward the contact line generated inside the droplet increases, so that more solute is transported in the contact line direction, the width of the ring is reduced, and the height of the ring is increased. In addition, the possibility of film shape control is mentioned, and it is shown that changing the evaporation rate distribution results in thin films with different shapes. As described above, the process of forming a ring on a relatively wet substrate has been sufficiently studied, but the process of suppressing the ring formation and forming a thin film with a uniform thickness has been sufficiently studied. Absent.

Also, Marangoni convection is considered as one of the causes of the flow generated inside the droplet in the evaporation process. Research is also underway to use this convection for thin film formation.

For example, Non-Patent Document 5 reports the results of film formation experiments using a solution obtained by mixing a small amount of a non-volatile solvent (acetophenone) with a polymer solution containing ethyl acetate as a main solvent. As a result, when a small amount of acetophenone, which is a non-volatile solvent, was mixed, the contact line of the droplet was greatly retracted to form a dot-like thin film. On the other hand, when a non-volatile solvent was not mixed, it was a ring-shaped thin film. In the same document, the receding of the contact line is considered to be the effect of Marangoni convection due to the increase in the acetophenone concentration in the contact line part due to evaporation. If the solvent component on the surface is not uniform, a difference in surface tension is generated due to the concentration distribution of the solvent, and Marangoni convection is induced by the gradient. Due to the stirring effect by this convection, the timing of fixing the contact line is delayed. It concludes that a thin film is produced.

Further, in Non-Patent Document 6, on a lyophilic substrate, by using a droplet in which silica is mixed with a binary solvent of water and formamide, and utilizing Marangoni convection utilizing a difference in surface tension between the solvents, silica is used. It is reported that a single membrane can be obtained. Here, it is considered that Marangoni convection has two directions depending on the combination of two-component solvents. The ring formation is promoted in the circulation flow accompanied by the upward flow at the center of the droplet, and the ring formation is suppressed in the circulation flow accompanied by the downward flow. However, solid silica is used in this experiment, and the polymer solution droplet has not been sufficiently examined.

In Non-Patent Documents 7 and 8, Marangoni convection is examined by experiments and numerical analysis using a suspension method using water and octane droplets. In this document, since the top of the droplet is cooled most in the pure solvent droplet on the substrate, the Marangoni convection that rises along the gas-liquid interface occurs, and the octane pure solvent liquid that is not easily affected by the surfactant. In the case of a drop, the flow is the same between the experiment and the numerical analysis, and ring formation is suppressed. However, in the case of a water drop that is easily affected by the surfactant, the Marangoni convection in the experiment is weakened and the effect of suppressing ring formation is reduced. It is described that it became clear. From this result, it is concluded that Marangoni convection generated at a clean interface without a surfactant suppresses the formation of a ring.

In Non-Patent Document 9, a thin film formation process of a droplet accompanied by a receding contact line with a large contact angle is performed using a polystyrene-xylene solution droplet having a diameter of 20 to 300 μm using an inkjet apparatus. Here, we are investigating the effects of the time it takes to fix the contact line, the average solute concentration at the time of fixing the contact line, and the evaporation rate on the shape of the thin film. It is reported that not only convection but also diffusion is an important factor in the movement of solutes on the free surface of droplets.

Further, in Non-Patent Document 10, in order to examine the ring suppression effect of the two-component solvent in the ink-jet film forming method, a follow-up experiment of Non-Patent Document 5 is performed and detailed studies are added. According to this report, Marangoni convection caused by the solvent concentration distribution in the early stage of evaporation stirs the inside of the droplet, and moves backward while making the solute concentration uniform. After the evaporation of the low-boiling solvent is completed, the solute concentration distribution becomes high-viscosity droplets, and the droplet viscosity increases when the contact line is fixed, and it is concluded that a dot-like thin film is formed. Attached. In the same document, it is reported that even when the initial viscosity is high, a dot-like thin film is formed instead of a ring shape.

As described above, various studies have been found on the ring formation that occurs in the process of forming a thin film from droplets. However, all of these have only studied the factors that cause ring formation. For example, for conductive fine particle dispersions used in the formation of wiring patterns, the optimum composition that can effectively refine the wiring patterns has been found. It has not been. On the other hand, the fine particle dispersions conventionally used in the field of printable electronics have a problem that the line width of the formed wiring is inevitably wide and the line width is unstable, and there is a limit to the miniaturization of the wiring pattern. Is the actual situation.

Therefore, in order to solve such a problem of the prior art, the present inventors proceeded with a study for the purpose of providing a fine particle dispersion capable of forming a fine wiring pattern with a uniform line width. Further, by using such a fine particle dispersion, studies have been conducted for the purpose of providing a fine and uniform wiring pattern and a method for forming a wiring pattern capable of forming such a wiring pattern. It was.

As a result of intensive studies to solve the above problems, the present inventors have found that a thin film with a fine pattern can be formed with a uniform line width by adding a specific surface conditioner to the fine particle dispersion. I found it. Specifically, the present invention has the following configuration.

[1] A fine particle dispersion containing fine particles and a surface conditioner,
The surface conditioning agent has a polysiloxane chain having a repeating unit containing a siloxane bond, or at least one polymer chain of a (meth) acrylic polymer chain, and at least one of a side chain and a terminal of the polymer chain. A fine particle dispersion having a hydrophilic group.
[2] The fine particle dispersion according to [1], wherein the surface conditioner has a polysiloxane chain as the polymer chain.
[3] The fine particle dispersion according to [1], wherein the surface conditioner is a compound represented by the following general formula (1).

[In the general formula (1), R ¹ to R ⁶ each independently represents a substituent, and at least one of R ¹ to R ⁶ is a hydrophilic group. A plurality of R ¹ and a plurality of R ² present in the molecule may be the same as or different from each other. n is an integer of 3 to 50. ]
[4] The fine particle dispersion according to [3], wherein at least one of R ¹ to R ⁶ includes a (meth) acrylic polymer chain.
[5] The fine particle dispersion according to [3] or [4], wherein a part of the plurality of R ¹ or a part of the plurality of R ² present in the molecule is a hydrophilic group.
[6] The fine particle dispersion according to any one of [1] to [5], wherein the hydrophilic group is a group represented by the following general formula (2).
General formula (2)
-(O-R ⁷ ) _m-
[In the general formula (2), R ⁷ is an alkylene group having 1 to 3 carbon atoms, and m is an integer of 20 to 30. ]
[7] The fine particle dispersion according to [6], wherein R ^{7 in the} general formula (2) is an ethylene group.
[8] The fine particle dispersion according to any one of [1] to [7], further containing a thickener.
[9] The fine particle dispersion according to [8], wherein the thickener is diethylene glycol.
[10] The fine particle dispersion according to any one of [1] to [9], wherein the fine particles are metal fine particles.
[11] The fine particle dispersion liquid according to any one of [1] to [10], wherein the fine particles are conductive fine particles.
[12] The fine particle dispersion according to [11], which is used for forming a wiring pattern.
[13] A wiring pattern formed using the fine particle dispersion according to [11].
[14] A step of supplying the fine particle dispersion according to [11] to the wiring pattern forming surface to form a coating film, and a step of forming the conductive layer by drying the coating film. A method of forming a wiring pattern.
[15] The method for forming a wiring pattern according to [14], wherein the method for supplying the fine particle dispersion is an inkjet method.

According to the fine particle dispersion of the present invention, a thin film with a fine pattern can be formed with a uniform line width. For example, when conductive fine particles are used as the fine particles of the fine particle dispersion, a fine wiring pattern can be formed. The wiring pattern thus formed can be suitably used as wiring for various electronic devices.

It is a graph which shows the relationship between the density | concentration of the surface conditioning agent in a surface conditioning agent solution, and surface tension. It is a schematic diagram which shows the balance of the force in a young formula. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.05% by mass of Compound 4-1 in a stripe shape with a dropping interval of 30 μm and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.05% by mass of Compound 4-1 in a stripe shape with a dropping interval of 50 μm, and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.05% by mass of Compound 3-2 in a stripe shape with a dropping interval of 30 μm and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.05% by mass of Compound 3-2 in a stripe shape with a dropping interval of 50 μm and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.1% by mass of compound 4-1 in a stripe shape with a dropping interval of 30 μm, and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.1% by mass of compound 4-1 in a stripe shape with a drop interval of 50 μm, and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.1% by mass of Compound 3-2 in a stripe shape with a dropping interval of 30 μm, and a photograph showing a planar shape. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing 0.1% by mass of Compound 3-2 in a stripe shape with a dropping interval of 50 μm and a photograph showing a planar shape. It is the figure which shows the cross-sectional shape of the wiring formed by drawing the fine particle dispersion liquid which has not added the surface conditioning agent in the shape of a stripe with a dropping space | interval of 30 micrometers, and the photograph which shows a planar shape. It is the figure which shows the cross-sectional shape of the wiring formed by drawing the fine particle dispersion liquid which has not added the surface conditioning agent in the shape of a stripe with a dropping space | interval of 50 micrometers, and the photograph which shows a planar shape. FIG. 2 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing compound 4-1 and diethylene glycol in a stripe shape with a dropping interval of 30 μm, and a photograph showing a planar shape. FIG. 4 is a diagram showing a cross-sectional shape of a wiring formed by drawing a fine particle dispersion containing compound 4-1 and diethylene glycol in a stripe shape with a drop interval of 50 μm and a photograph showing a planar shape. It is the figure which shows the cross-sectional shape of the wiring formed by drawing the fine particle dispersion liquid which contains diethylene glycol and does not contain a surface conditioning agent in the shape of a stripe with a dropping space | interval of 30 micrometers, and a photograph which shows a planar shape. It is the figure which shows the cross-sectional shape of the wiring formed by drawing the fine particle dispersion liquid which does not contain diethylene glycol and does not contain a surface conditioning agent in the shape of a stripe with a drop interval of 50 micrometers, and a photograph which shows a planar shape. 6 is a photograph showing changes in wiring line width depending on whether or not left after baking in Example 3. 6 is a photograph showing changes in wiring line width depending on whether or not left after baking in Example 3. It is a photograph which shows the presence or absence of the wiring surface crack after baking in Example 6. FIG.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Fine particle dispersion)
The fine particle dispersion of the present invention contains fine particles and a surface conditioner. The surface conditioning agent has at least one of a polysiloxane chain having a repeating unit containing a siloxane bond or a (meth) acrylic polymer chain, and at least one of a side chain and a terminal of the polymer chain. Have a hydrophilic group. In the present invention, the “hydrophilic group” refers to a group capable of forming a hydrogen bond with water, and the “surface modifier” refers to physical properties (viscosity, surface tension, contact angle) of the metal fine particle dispersion. Etc.). Further, in this specification, the notation “(meth) acryl” is a concept including both acrylic and methacrylic.

The fine particle dispersion is supplied to the thin film forming surface and then dried to form a thin film. Here, when the fine particle dispersion of the present invention contains the above-mentioned surface conditioner, its wetting and spreading is effectively suppressed when it is dropped onto the thin film forming surface. Therefore, by using this fine particle dispersion, even when the target thin film pattern is fine, a thin film that accurately reflects the pattern can be formed with a uniform line width. Here, the reason why the droplets of the fine particle dispersant are difficult to spread out is that the hydrophilic groups of the surface conditioner contained in the droplets act to aggregate with each other to form a solid-liquid (film-formation surface and metal fine particle dispersion). It is presumed that the surface tension γ _{SL (} between the liquids) increased and the contact angle of the droplets increased.

The surface conditioner used in the fine particle dispersion of the present invention preferably has at least a polysiloxane chain. Especially, it is preferable that it is a compound represented by following General formula (1).

In the general formula (1), R ¹ to R ⁶ each independently represent a substituent, and at least one of R ¹ to R ⁶ is a hydrophilic group. A plurality of R ¹ and a plurality of R ² present in the molecule may be the same as or different from each other.
R ¹ to R ⁶ may all be a hydrophilic group or a part thereof may be a hydrophilic group, but at least one of R ¹ and R ² may be a hydrophilic group. preferable. In addition, each of the plurality of R ¹ and the plurality of R ² present in the molecule may be a hydrophilic group or a part thereof may be a hydrophilic group. Is preferably a hydrophilic group.
The hydrophilic group which R ¹ to R ⁶ can take is preferably a group having a polyoxyalkylene structure represented by the following general formula (2).

In the general formula (2), R ⁷ is an alkylene group having 2 to 3 carbon atoms, and m is an integer of 20 to 30.

The substituents that R ¹ to R ⁶ can take are not particularly limited. The substituent may be a group containing a polymer chain having a repeating unit or a group not having a repeating unit. Examples of the polymer chain having a repeating unit include a (meth) acrylic polymer chain. The (meth) acrylic polymer chain may have a hydrophilic group in at least one of its side chain and terminal. Moreover, a polysiloxane chain can also be mentioned as a polymer chain which has a repeating unit. Such a polysiloxane chain may also have a hydrophilic group in at least one of its side chain and terminal. Furthermore, the polymer chain having a repeating unit may be one in which a (meth) acrylic polymer chain and a polysiloxane chain are linked. Such a linking chain may also have a hydrophilic group in at least one of its side chain and terminal.
Examples of the substituent having no repeating unit include a substituted or unsubstituted alkyl group. The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. The alkyl group herein may be linear, branched or cyclic, but is preferably linear or branched, and more preferably linear. The alkyl group is more preferably an ethyl group or a methyl group.
n is an integer of 3 to 50, and more preferably 3 to 30.

Preferred examples of the surface conditioner include compounds represented by the following general formulas (3) and (4). These can be obtained as commercial products. For example, BYK307 and BYK348 (both manufactured by Big Chemie Japan) can be mentioned.

In the surface conditioning agent represented by the general formula (1), compounds represented by the following general formulas (3) and (4) are more preferably used.

In the general formula (3), the Alkylene oxide chain represents a group containing a repeating unit of the polyoxyalkylene structure shown in the general formula (2), and preferably represents an ethylene oxide chain. R ⁸ represents an alkyl group having 1 to 3 carbon atoms. n is an integer of 3 to 100, and more preferably 3 to 50.

In the general formula (4), the Alkylene oxide chain represents a group containing a repeating unit of the polyoxyalkylene structure shown in the general formula (2), and preferably represents an ethylene oxide chain. R ⁹ represents an alkyl group having 1 to 3 carbon atoms. x, y, and z each represents an integer, x represents 1 to 10, y represents 0 to 10, and z represents 0 to 10. x represents 1 to 3, y represents 0 to 3, and z represents 0 to 3. y and z are not 0 at the same time.

The surface conditioner preferably used in the present invention typically has the following structure.
Exemplary compound (3-1) represented by formula (3) R ⁸ = methyl group Alkylene oxide chain = ethylene oxide chain having about 40 ethylene oxide units n = about 20
(3-2) R ⁸ = methyl group Alkylene oxide chain = ethylene oxide chain having about 50 ethylene oxide units n = about 40
(3-3) R ⁸ = methyl group Alkylene oxide chain = ethylene oxide chain having about 10 ethylene oxide units n = about 20
(3-4) R ⁸ = ethyl group Alkylene oxide chain = ethylene oxide chain having about 20 ethylene oxide units n = about 20
(3-5) R ⁸ = propyl group Alkylene oxide chain = ethylene oxide chain having about 50 ethylene oxide units n = 50

Exemplary compound (4-1) represented by general formula (4) R ⁹ = methyl group Alkylene oxide chain = ethylene oxide chain having about 10 ethylene oxide units x = 1, y = 1, z = 1
(4-2) R ⁹ = methyl group Alkylene oxide chain = ethylene oxide chain having about 20 ethylene oxide units x = 1, y = 1, z = 0
(4-3) R ⁹ = methyl group Alkylene oxide chain = ethylene oxide chain having about 40 ethylene oxide units x = 1, y = 2, z = 2
(4-4) R ⁹ = propyl group Alkylene oxide chain = ethylene oxide chain having about 20 ethylene oxide units x = 1, y = 1, z = 1
(4-5) R ⁹ = methyl group Alkylene oxide chain = ethylene oxide chain having about 50 ethylene oxide units x = 2, y = 20, z = 20

The surface conditioner included in the present invention can be obtained as a commercial product from various manufacturers, and examples include products such as Big Chemie Japan, Toshiba Silicone, Shin-Etsu Chemical. For example, a polyether-modified dimethylsiloxane-modified surface conditioner manufactured by Big Chemie Japan may be used.

The content of the surface conditioner in the fine particle dispersion is preferably 0.001 to 5% by mass, and more preferably 0.01 to 1% by mass with respect to the fine particles as the solute. The content of the surface conditioner in the fine particle dispersion is preferably 0.01 to 5% by mass, more preferably 0.05 to 4% by mass, and more preferably 0.1 to 3% by mass with respect to the solvent. More preferably, it is still more preferably 0.3 to 2% by mass.

The fine particles contained in the fine particle dispersion of the present invention may be inorganic fine particles or organic fine particles, but are preferably inorganic fine particles. As the inorganic fine particles, fine particles (metal fine particles) made of a material containing metal atoms, such as various metals, alloys, or metal oxides, can be suitably used. In addition, for example, in the fine particle dispersion for forming a wiring pattern, any conductive fine particles that are usually used in the field of printable electronics can be used, among which gold, silver, palladium, copper, indium tin oxide, cuprous oxide (Cu It is preferable to use ₂ O) fine particles.
The particle size of the fine particles is not particularly limited, but is preferably in the order of nanometers (1 to several hundred nm). Here, the particle size of the fine particles in the present invention refers to an average particle size measured by a commercially available particle size distribution measuring device such as a light scattering method.

The content of the fine particles in the fine particle dispersion varies depending on the use of the fine particle dispersion and the coating process used, but is preferably 1 to 90% by mass, and more preferably 10 to 80% by mass.
The present invention is effective not only when these nanoparticles are used, but also when a dispersion of nanomaterials having no particulate shape such as silver nanowires is applied.

The dispersion medium of the metal fine particle dispersion is not particularly limited, and aromatics such as benzene, toluene, xylene, chlorobenzene, diethyl ether, dibutyl ether, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethylene glycol dimethyl ether and the like. Ethers, esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl propionate, γ-butyrolactone, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, carbonization such as hexane, heptane, octane, nonane, tetradecane, etc. Hydrogens, halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, organic acids such as formic acid, acetic acid, propionic acid, N, N-dimethylformamide, N, N-dimethylacetoa De, include polar solvents and water, such as N- methylpyrrolidone, also mixtures of these solvents can be used.

In addition to the components described above, additives may be added to the fine particle dispersion. Examples of the additive include a thickener. Examples of the thickener include glycol thickeners such as diethylene glycol. By adding a thickener to the fine particle dispersion, the viscosity increases, and the flatness of the formed thin film can be remarkably improved.

(Wiring pattern and formation method thereof)
The wiring pattern of the present invention is the fine particle dispersion of the present invention, which is formed using a fine particle dispersion containing conductive fine particles as fine particles. As described above, this wiring pattern is formed with a uniform line width that accurately reflects the pattern even when the set pattern is fine, because the fine particle dispersion of the present invention has the property that it is difficult to spread. Has been. For this reason, this wiring pattern can be used suitably as a wiring pattern of various electronic components.

Specifically, the wiring pattern can be formed by supplying the fine particle dispersion of the present invention to the wiring forming surface and drying it.
The method for supplying the fine particle dispersion is not particularly limited, but for example, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating. Examples thereof include a coating method such as a printing method, a screen printing method, a flexographic printing method, an offset printing method, an ink jet method, and a printing method such as a microcontact printing method. Among them, a printing method is preferably used, and an ink jet method is used. Is more preferable.

The wiring formation surface means a surface on which wiring is formed, and the type is not particularly limited as long as it is a surface on which wiring can be formed. A typical wiring forming surface is a substrate surface. The material of the substrate can be appropriately selected from the materials of the substrate that are usually used according to the application. For example, a substrate made of an inorganic material such as glass, ITO (indium tin oxide), silicon, polyimide, PET ( Examples thereof include a substrate made of a polymer typified by polyethylene terephthalate), but is not limited thereto, and is applicable to all polymer substrates supplied as a film.
The wiring pattern can be formed, for example, by supplying the fine particle dispersion of the present invention to a region where wiring on the substrate is to be formed by a supply method such as an ink jet method. If the fine particle dispersion of the present invention is used, the expansion of the line width can be remarkably suppressed as compared with the case where it is not used, so that the intended line width can be easily realized.
In the wiring pattern, a region having high wettability with respect to the fine particle dispersion of the present invention is formed in a pattern on a substrate in advance, and the fine particle dispersion of the present invention is accumulated on such a high wettability region. You can also When using a substrate having low wettability to the fine particle dispersion of the present invention, a region having high wettability to the fine particle dispersion of the present invention can be formed in a pattern on the substrate. Conversely, when using a substrate having high wettability to the fine particle dispersion of the present invention, a region having low wettability to the fine particle dispersion of the present invention can be formed on the substrate in a negative pattern. Forming in a negative pattern here means forming in a region excluding a region where the fine particle dispersion is desired to exist. The pattern can be formed, for example, by spin-coating a photo-curable resin solution on the substrate, exposing it in a pattern with ultraviolet rays, and then washing away the soluble region with a solvent. As an example, when a self-organized material substituted with fluorine is applied to a substrate and a substrate finely patterned with light is used, the droplets discharged by using the fine particle dispersion of the present invention are lyophilic and repellent. Even when applied over the liquid region, the liquid droplets gather from the liquid repellent region to the lyophilic region, and the wiring can be drawn according to the patterned region.

The drying temperature of the fine particle dispersion supplied to the thin film forming surface is preferably 20 to 300 ° C, more preferably 50 to 200 ° C. The drying time of the fine particle dispersion is preferably 1 to 60 minutes, more preferably 2 to 20 minutes.
Such drying is called baking, especially when performed at high temperatures. When baking is performed after forming a wiring pattern using a conventional fine particle dispersion, there is a problem that the wiring after baking becomes extremely thick as time elapses after the wiring pattern is formed. By using the fine particle dispersion of the present invention, it is possible to suppress the influence of thickened wiring after baking depending on the time from formation of the wiring pattern to baking. For this reason, if the fine particle dispersion of the present invention is used, a series of operations from wiring pattern formation to baking can be performed with ease, and the cost of manufacturing equipment can be suppressed and the yield can be increased.
Further, if the wiring is formed using the fine particle dispersion of the present invention, there is an advantage that cracks on the surface of the wiring after baking can be suppressed and the specific resistance of the wiring can be lowered. Conventionally, cracks are observed on the surface of the wiring after baking, and there is a problem that the conductive path is restricted by the influence and the specific resistance of the wiring becomes high. When the wiring is formed using the fine particle dispersion of the present invention, the occurrence of cracks after baking can be suppressed, and the conductive area can be increased, so that the specific resistance can be lowered. For this reason, when the fine particle dispersion of the present invention is used, there is an advantage that a high-quality wiring can be efficiently formed.

Hereinafter, the features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
<Material used for experiment>
In this example, γ-butyrolactone (GBL) is used as a solvent, cuprous oxide (Cu ₂ O) nanoparticles (particle size: 10 to 20 nm) are used as metal fine particles, and a siloxane-based surface conditioner is used as a surface conditioner. A certain compound 4-1 and compound 3-2 (both manufactured by Big Chemie Japan) were used. The physical properties of γ-butyrolactone are a vapor pressure of 200 Pa, a surface tension of 43.3 mN / m, a viscosity of 1.7 mPa · s, and a density of 1131 kg / m ³ . Compound 4-1 is a siloxane compound having a polyoxyethylene chain in the side chain, and compound 3-2 is a siloxane compound having a polyoxyethylene chain at the terminal, and is a surface conditioner that satisfies the requirements of the present invention. .

<Measurement of surface tension>
The surface tensions of the surface conditioner solutions having different concentrations were measured.
A surface conditioning agent was dissolved in γ-butyrolactone to prepare a surface conditioning solution. As the surface conditioner, Compound 3-2 and Compound 4-1 were used. For each compound, a solution was prepared in which the initial surface conditioner concentration was changed to 0, 0.05, 0.1, 0.5% by mass. An electronic balance (manufactured by A & D, trade name ER182A, minimum weight 0.00001 g) was used for measurement of mass for solution adjustment. For each solution of these surface conditioners, the surface tension was measured three times, and the average value was taken. The surface tension was measured after setting a thermostat (ASONE) connected to the sample cup of the surface tension meter to 25 ° C. and then leaving it for 30 minutes or more.
For measuring the surface tension, an automatic surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., trade name CBVP-Z) was used. There are platinum plate method and ring method as the measuring method in this apparatus, but platinum plate method was adopted in this experiment. The platinum plate method is a method of measuring the surface tension (force drawn into the test solution) generated when the plate is immersed in the test solution from the side and pulled out. As a feature of this apparatus, since the surface state of the test solution is not changed, it can be measured even with a high viscosity liquid or a surfactant aqueous solution, and the change with time can be measured. Similar to the viscometer, this apparatus can be connected to a sample cup and a thermostatic bath, and can control the temperature.
The measurement result of the surface tension is shown in FIG. As shown in FIG. 1, the surface tension decreased with the surface modifier concentration. When compound 3-2 was used as a surface conditioner, the surface tension hardly decreased as the concentration increased. However, when compound 4-1 was used as a surface conditioner, the surface tension increased as the concentration increased. Fell. This is presumably because the compound 4-1 has a lower molecular weight and higher solubility than the compound 3-2, and is difficult to orient at the gas-liquid interface.

<Measurement of contact angle>
The change in contact angle due to the addition of the surface conditioner in the metal fine particle dispersion was measured. As the metal fine particle dispersion, a dispersion in which cuprous oxide (Cu ₂ O) nanoparticles were dispersed in γ-butyrolactone was used. To this dispersion, a metal fine particle dispersion in which compound 4-1 or compound 3-2 is added as a surface conditioner at a concentration of 0.05% by mass with respect to the solvent, and a metal fine particle dispersion not added are prepared. And measured. Each metal fine particle dispersion was discharged drop by drop onto a glass substrate that had been UVO ₃ treated using an inkjet nozzle, and the change in contact angle due to the addition of a surface conditioner was examined from the wet diameter after dropping.
The measurement was performed using an inkjet head (product name: Pulse Viewer) manufactured by CLUSTER TECHNOLOGY, using an ink jet head (product name: Pulse Injector, manufactured by CLUSTER TECHNOLOGY) having a nozzle diameter of 25 μm. If this apparatus is used, the stage can be moved back and forth and right and left by placing the work on which the droplets are to be deposited on the work fixing table on the upper surface of the stage and controlling the stage controller. Observation of the flying state and landing state of the droplet was performed with a USB camera and confirmed on a personal computer screen.
As a result of the measurement, the wet diameter after dropping of the metal fine particle dispersion added with the surface conditioner was smaller than the wet diameter after dropping of the metal fine particle dispersion not added with the surface conditioner. This indicates that the contact angle is increased by the addition of the surface conditioner.
The contact angle of a droplet on a smooth substrate is explained by the balance of forces in the Young equation. FIG. 2 shows a balance diagram of forces in the Young equation. In general solutions, the smaller the surface tension of the liquid, the smaller the contact angle. From the measurement result of the above surface tension (FIG. 1), the surface tension decreased with the concentration of the surface conditioner when any surface conditioner was used. The difference in surface tension and contact angle depending on the type of surface modifier was considered from the molecular structure of the surface modifier as follows. Compound 4-1 has a polyethylene oxide chain in the structure and a small molecular weight. Compound 3-2 is terminated with a polyethylene oxide chain, and its molecular weight is larger than that of Compound 4-1. Siloxane groups and ethylene oxide units have hydrophilic properties, and aralkyl groups have hydrophobic properties. When compound 4-1 is added, the force of aggregating polyethylene oxide chains in the droplets acts, and the surface tension γ _SL between the solid and liquid increases, so the contact angle is thought to have increased significantly.

<Formation of metal wiring pattern>
Next, the effect of the type of surface conditioner, initial surface conditioner concentration, and viscosity on the external shape and cross-sectional shape of the wiring is formed by drawing the metal fine particle dispersion on the lyophilic glass substrate. investigated.

For drawing the metal fine particle dispersion, an ink jet apparatus (product name: Desk Viewer, manufactured by CLUSTER TECHNOLOGY) similar to that used in the measurement of the above physical property values was used. Here, an internal program that creates drawing patterns on the Desk Viewer dedicated software (product name Desk Designer, manufactured by CLUSTER TECHNOLOGY), transfers the data to the internal memory of the controller, and then executes the program data in response to a command from the PC The method of drawing was used.
An ultra-deep shape measuring microscope (manufactured by KEYENCE, product name VK-8510) and a stylus type surface shape measuring device (manufactured by ULVAC, product name DEKTAK 6M) were used for the measurement of the wiring cross-sectional shape and the photographing of the wiring outer shape. . This ultra-deep shape measuring microscope is a laser microscope capable of scanning the surface shape of an object in three dimensions. The wavelength of the semiconductor laser is 685 nm, and the optical system of the laser is a confocal system. The measurement principle is as follows. First, a laser beam is irradiated vertically on an object on an object through an objective lens. If there are interfaces with different refractive indexes, the laser will reflect. The intensity of the reflected light is measured by the light receiving element. If the objective lens is moved up and down at a minimum pitch of 0.01 μm and the intensity of the reflected light is measured at each objective lens position, a vertical distribution of the reflected light intensity can be obtained. The position where the reflected light intensity is maximum is the interface position. A three-dimensional surface shape can be obtained by two-dimensionally scanning the above interface position specifying method. The minimum vertical resolution at the time of measurement is 0.01 μm. The maximum measurement range is 295 μm × 221 μm. A series of measurements can be automatically performed by inputting measurement conditions such as angle of view, resolution, incident light quantity, and measurement mode. Moreover, it has a halogen light and can also be used as a normal stereomicroscope. When used as a stereomicroscope, the maximum measurement range is 1479 μm × 1109 μm. On the other hand, the stylus type surface shape measuring apparatus physically measures a two-dimensional sample surface shape by moving a sample stage linearly on a precise reference surface under a diamond stylus. . Changes in the sample surface are exchanged for the vertical movement of the stylus and are detected by a differential transformer. The detected signal is converted from analog to digital by an integrating AD converter. The digitized signal is stored in the memory of the computer, and after performing data processing such as horizontal adjustment and enlargement, the surface state is displayed on the monitor. The tip radius of the stylus is 12.5 μm and is thick at an angle of 60 °. The stylus pressure can be programmed in the range of 1 to 15 mg, and a measurement distance of 50 to 30000 μm can be measured at 300 points / s. The maximum number of sampling data is 60000 points.

As a mass meter, an electronic balance (manufactured by ER182A, trade name AND, minimum weight 0.00001 g) was used. A UV ozone cleaner (manufactured by Filgen, trade name UV253) was applied to the glass substrate. This device generates ozone from oxygen by light with an extremely short wavelength (185 nm), and removes organic pollutants attached to the substrate in combination with the chemical bond dissociation effect of light with a short wavelength (254 nm). It is structured. The generated ozone was decomposed by an ozone killer (manufactured by Filgen).

Before the experiment, the level on the stage was confirmed using a leveler. Dust was used to remove dust around the experimental apparatus and on the stage. The ambient temperature was set constant by leaving the ambient temperature at 25 ° C. and leaving it for about 60 minutes. The ink jet head was connected to an ink jet driver, inserted into the PIJ fixing bracket of the ink jet apparatus by sliding, and the fixing screw was fastened and fixed. The experiment was performed with the inkjet driver driving waveform fixed at B and the repetition frequency at 1000 Hz. Similarly, the stage moving speed was fixed at 1500 μm / s to perform drawing. In order to remove organic pollutants before the start of the experiment, the glass substrate to be used was put in a UV ozone cleaner, and an experiment was prepared so that drawing could be started within 30 minutes after the completion of the UVO ₃ treatment.

Using γ-butyrolactone (GBL) as a solvent, cuprous oxide (Cu ₂ O) nanoparticles (particle size 10 to 20 nm) as metal fine particles, and using compound 3-2 and compound 4-1 as surface conditioners A metal fine particle dispersion was prepared. Here, the concentration of the surface conditioner was 0% by mass, 0.05% by mass or 0.1% by mass with respect to the solvent. In addition, a metal fine particle dispersion in which diethylene glycol was blended as a thickener in a dispersion having the same composition as these was also prepared.
Using each of the prepared metal fine particle dispersions, three metal wirings were formed by an inkjet nozzle at a dropping interval of 30 μm or 50 μm according to the following procedure.
(1) The fine metal particle dispersion was sucked into the syringe through the filter.
(2) A syringe was connected to the cartridge and filled with the metal fine particle dispersion.
(3) A cartridge filled with the metal fine particle dispersion and connected with a syringe was connected to PIJ.
(4) It was confirmed again that there were no air bubbles in the tube of the cartridge, and the metal fine particle dispersion in the cartridge was extruded with a connected syringe and introduced into the PIJ. The extrusion speed was such that the metal fine particle dispersion proceeded at 1 mm / s in the cartridge tube.
(5) After confirming that the metal fine particle dispersion was discharged from the nozzle, the syringe was gently removed from the cartridge. The head was fixed so that the PIJ and the cartridge were horizontal. If the metal fine particle dispersion came out of the nozzle, the nozzle surface was lightly wiped with a Kim wipe moistened with a solvent.
(6) The metal fine particle dispersion was continuously discharged onto an untreated glass substrate, and the voltage was changed so as to obtain an appropriate discharge state while observing the discharge state.
(7) When an appropriate discharge state was maintained for 1 to 2 minutes, continuous discharge was stopped, and the landing distance was adjusted while checking the positions of the nozzle surface and the workpiece surface with a USB camera.
(8) The glass substrate after UVO ₃ treatment taken out from the UV ozone cleaner was replaced with an untreated glass substrate, and after preliminary ejection, a wiring pattern was drawn on the substrate with a droplet spacing of 30 μm and 50 μm.
(9) The glass substrate was baked at 130 ° C. for 10 minutes on a hot plate (manufactured by ASONE).
(10) The external shape and cross-sectional shape of the wiring were measured with VK-8510 or DEKTAK 6M.

3 to 16 show the measurement results of the cross-sectional shape and planar shape of each formed metal wiring. Here, in each figure, A and B each represent one of the three metal wirings, and the observation points are different.
From these measurement results, the effect of the surface modifier type, the effect of the initial concentration of the surface modifier, and the effect of the viscosity were evaluated.

From the comparison between the measurement results of the fine particle dispersion added with the compound 4-1 or the compound 3-2 shown in FIGS. 3 to 10 and the measurement results of the fine particle dispersion without addition of the surface modifier shown in FIGS. It was found that the wiring width can be reduced by adding a regulator. It was also found that there was a difference in the reduction of the wiring width depending on the type of the surface conditioner. This is thought to be due to the fact that the contact angle was increased by the addition of the surface conditioner, and accordingly the wiring width was reduced. The reason why the wiring width was reduced when 0.05% by mass of compound 4-1 was added compared to when 0.05% by mass of compound 3-2 was added was also explained in the measurement of the contact angle described above. Thus, the contact angle of compound 3-2 is increased as in the case of compound 4-1, but the contact angle is increased compared to compound 4-1, because the straight chain is long and the proportion of ethylene oxide in the structure is small. This is thought to be due to the small size.
In addition, in the cross-sectional shape, the ring shape could be suppressed by adding a surface conditioner. In film formation experiments on a smooth substrate according to conventional research, it is known that the ring shape is suppressed as the contact angle increases. However, ring-shaped wiring was formed even at 0.05% by mass of Compound 4-1 having the smallest wiring width. It is known from previous research that the ring shape is suppressed as the viscosity increases, as well as the contact angle. This is because the viscosity was small in the system to which no thickener was added, so it was greatly affected by the viscosity. Conceivable.
In addition, the addition of the surface conditioner was stable because the wiring width was reduced and the variation in the wiring width was reduced. This is considered that the surface conditioning agent worked as a leveling agent by orienting at the interface. It was also confirmed that the smoothness of the surface of the metal wiring formed at the same time was improved.

7 to 10 show the measurement results of the metal wiring in which the initial concentration of compound 3-2 and compound 4-1 was 0.1% by mass. Although the change in the liquid amount was observed due to the change in physical properties, the cross-sectional shape of the wiring was still a ring shape, and the tendency was not different from the case where the initial addition concentration was 0.05 mass%. In the case of using a surface conditioner for coating, when the surface conditioner concentration is increased, the solute and particles are aggregated by reaching the critical micelle concentration. From the enlarged image of the wiring formed by adding 0.1% by mass of the surface conditioner, particles that were not seen when 0.05% by mass were added were observed. When 0.1% by mass was added, the critical micelle concentration It is considered that the influence of the addition of the surface conditioner was not different from the addition of 0.05% by mass. From this result, the following metal wiring formation experiment was conducted using a metal fine particle dispersion liquid in which the concentration of the surface conditioner was fixed at 0.05 mass% and a thickener was blended.

As shown in FIGS. 13 to 14, even in a system to which a thickener was added, a wiring having a flat cross-sectional shape could be formed by adding 0.05 mass% of compound 4-1. . It is considered that the ring shape could be suppressed by increasing the contact angle and viscosity. Moreover, the smoothness of the wiring surface was also improved, and the leveling effect of the surface conditioner could be confirmed.
From this experiment, it is possible to make the metal wiring finer by adjusting the type and initial concentration of the surface modifier added to the metal fine particle dispersion, and by optimizing the viscosity, the metal wiring has a flat cross-sectional shape. It was shown that it is possible to form

As described above, when the surface conditioner was added to the fine particle dispersion, the contact angle changed depending on the concentration of the addition. Depending on the type of surface conditioner, the surface tension could be lowered and the contact angle could be increased. In addition, by adding a surface conditioner to the fine particle dispersion, the wiring width of the formed metal wiring is reduced and thinning is possible. In addition, the leveling effect of the surface conditioner stabilizes the wiring width and improves the smoothness of the wiring surface. From these results, it was shown that a wiring having a flat cross-sectional shape can be formed by optimizing the type, addition concentration and viscosity of the surface conditioner.

[Example 2]
In Example 2, the case where silver nanoparticles and a mixed solvent were used was examined.
<Procedure>
In Example 2, a solvent obtained by mixing water and an organic solvent was used as a solvent, and silver nanoparticles (DIC Corporation, JAGLT-01) were used as metal particles. To this particle dispersion, 0.05% by mass of the surface conditioning agent of the present invention (Compound 4-1) was added and applied onto the line in the same system as in Example 1 with droplet dropping intervals of 50 μm and 100 μm. Went. For comparison, a metal fine particle dispersion without addition of a surface conditioner was also prepared and applied in the same manner.
<Result>
As a result, under the condition of the drop interval of 50 μm, the sample without the surface conditioner had a line width of 120 μm, whereas the sample to which the surface conditioner of the present invention was added had a pattern with a thinner line width of 70 μm. Obtained. Under the condition where the drop interval is 100 μm, the sample without the surface conditioner was not connected to the liquid droplets, but the sample with the surface conditioner of the present invention was dotted with a line pattern. It was observed. In addition, when the resistance value of the line obtained at the dropping interval of 50 μm was measured with a tester, no difference was observed depending on whether or not the surface conditioner was added.
From the above results, it was proved that by adding the surface conditioner of the present invention, the line width is narrowed and fine drawing can be performed, the connection of droplets is improved, and a smoother line pattern can be obtained.
Also, in both silver nanoparticles and copper nanoparticles, the use of aralkyl-modified polymethylsiloxane (for example, BYK322, trade name BYK322) as a surface conditioner improves the connection of the droplets. It was confirmed that a smooth line pattern could be formed.

[Example 3]
In Example 3, the case where various surface conditioners were used together with silver nanoparticles was examined.
<Procedure>
In Example 3, tetradecane was used as the solvent, and silver nanoparticles (Harima Kasei Co., Ltd., trade name NPS-JL) were used as the metal particles. In a dispersion of silver nanoparticles dispersed in tetradecane (silver content 52.5 mass%), as a surface conditioner, compound 4-1, compound 3-2, compound 5 (dimethylsiloxane, molecular weight 100,000; Shin-Etsu Chemical) 2 mass% of a compound 6 (trade name KF96) or compound 6 (a compound having both a polyethylene oxide chain and an acrylic polymer chain in a siloxane skeleton; manufactured by BYK Japan Japan, trade name BYK3550) is added to the solvent. A metal fine particle dispersion was prepared. For comparison, a metal fine particle dispersion without a surface conditioner was also prepared. In the same manner as in Example 1, coating was performed on the line at a droplet dropping interval of 50 μm in a system using a nozzle having a diameter of 25 μm. Immediately after application or after standing at room temperature (20 ° C.) for 2 minutes, baking was performed at 150 ° C. for 60 minutes.
<Result>
The results are shown in FIG. 17 and FIG. When the sample without the surface conditioner was baked immediately after application, the line width of the wiring was 460 μm, and when baked 2 minutes after application, the line width was increased to 600 μm or more. On the other hand, the line width of the sample to which the surface conditioner was added was thinner than that of the non-added sample. Samples added with compound 4-1, compound 3-2 and compound 6 having a polyalkylene oxide chain have a line width of 150 μm or less when baked immediately after coating, and a line width of 200 μm when baked 2 minutes after coating. The effect of the time until baking after application was small. Among them, in the sample to which compound 3-2 and compound 6 were added, the line width when baked 2 minutes after the application was almost the same as the line width when baked immediately after application, and both were preferred to be 80 μm or less. It was. Compound 3-2 was particularly preferred with a line width of 60 μm or less in any case.
Being less affected by the time until baking after coating means that the metal fine particle dispersion added with the surface conditioner is easy to handle and has a wide range of applications and applications.

[Example 4]
In Example 4, the influence was examined by the concentration of the surface conditioner.
<Procedure>
In Example 4, tetradecane was used as a solvent, and silver nanoparticles (Harima Kasei Co., Ltd., trade name NPS-JL) were used as metal particles. In a dispersion obtained by dispersing silver nanoparticles in tetradecane (silver content: 52.5% by mass), compound 4-1 as a surface conditioning agent was 0.01% by mass, 0.10% by mass, and 1. 00% by mass and 2.00% by mass were added to obtain a metal fine particle dispersion. For comparison, a metal fine particle dispersion without a surface conditioner was also prepared. In the same manner as in Example 1, coating was performed on the line at a droplet dropping interval of 20 μm in a system using a nozzle having a diameter of 25 μm. Immediately after the application, baking was performed at 150 ° C. for 60 minutes.
<Result>
As a result, it was confirmed that the sample in which 0.01% by mass of the compound 4-1 was added with respect to the solvent had a somewhat smaller wiring line width than the sample to which no compound was added. The sample obtained by adding 0.10% by mass of the compound 4-1 to the solvent has a narrow line width, and the sample obtained by adding 1.00% by mass or 2.00% by mass of the compound 4-1 to the solvent. Both achieved extremely narrow line widths. Since the line width was almost the same at 1.00% by mass and 2.00% by mass, when compound 4-1 was used as the surface conditioner under the conditions of Example 4, it was 1.00% by mass with respect to the solvent. % Addition was shown to be sufficient.

[Example 5]
In Example 5, the specific resistance after baking was examined.
<Procedure>
In Example 5, tetradecane was used as the solvent, and silver nanoparticles (manufactured by Iox Corporation) were used as the metal particles. To a dispersion liquid in which silver nanoparticles are dispersed in tetradecane (silver content: 52.5 mass%), 0.50 mass% of compound 3-2 as a surface conditioner is added to the solvent, did. For comparison, a metal fine particle dispersion without a surface conditioner was also prepared. In the same manner as in Example 1, coating was performed using a system using a nozzle having a diameter of 25 μm. Immediately after the application, baking was performed at 150 ° C., 180 ° C., 210 ° C., and 240 ° C. for 60 minutes.
<Result>
The results of measuring the specific resistance of the wiring surface after baking are shown in the following table. As is apparent from the table, it was confirmed that the specific resistance was reduced by adding the surface conditioner. This is because, in the sample to which the surface conditioner is not added, cracks are generated on the surface after baking, the conductive path is limited, and the conductive area is reduced, while in the sample to which the surface conditioner is added, after baking. This is probably because cracks were hardly observed on the surface of the film, and the area of the conductive path was increased.

[Example 6]
In Example 6, the surface crack after baking was examined.
<Procedure>
In Example 6, tetradecane was used as the solvent, and silver nanoparticles (manufactured by Iox Corporation) were used as the metal particles. To a dispersion liquid in which silver nanoparticles are dispersed in tetradecane (silver content: 52.5% by mass), 2.00% by mass of compound 3-2 as a surface conditioning agent is added to the solvent, did. For comparison, a metal fine particle dispersion without a surface conditioner was also prepared. In the same manner as in Example 1, coating was performed using a system using a nozzle having a diameter of 25 μm. Immediately after the application, baking was performed at 150 ° C. for 60 minutes.
<Result>
The result of observing the wiring surface state after baking is shown in FIG. In the sample to which no surface conditioner was added, cracks were observed on the surface after baking, but in the sample to which the surface conditioner was added, no cracks were observed on the surface after baking.

According to the fine particle dispersion of the present invention, the flatness is high and a fine thin film can be formed. For this reason, if the fine particle dispersion of the present invention is used, it is possible to form a fine wiring pattern with high flatness without using high-cost vacuum / photolithography process and etching process. For this reason, this invention can be utilized effectively for wiring formation, such as an electronic component, and its industrial applicability is high.

Claims

A fine particle dispersion containing fine particles and a surface conditioner,
The surface conditioning agent has a polysiloxane chain having a repeating unit containing a siloxane bond, or at least one polymer chain of a (meth) acrylic polymer chain, and at least one of a side chain and a terminal of the polymer chain. A fine particle dispersion having a hydrophilic group.
The fine particle dispersion according to claim 1, wherein the surface conditioner has a polysiloxane chain as the polymer chain.
The fine particle dispersion according to claim 1, wherein the surface conditioner is a compound represented by the following general formula (1).

[In the general formula (1), R 1 to R 6 each independently represents a substituent, and at least one of R 1 to R 6 is a hydrophilic group. A plurality of R 1 and a plurality of R 2 present in the molecule may be the same as or different from each other. n is an integer of 3 to 50. ]
The fine particle dispersion according to claim 3, wherein at least one of R 1 to R 6 is a substituent containing a (meth) acrylic polymer chain.
The fine particle dispersion according to claim 3 or 4, wherein a part of the plurality of R 1 or a part of the plurality of R 2 present in the molecule is a hydrophilic group.
The fine particle dispersion according to any one of claims 1 to 5, wherein the hydrophilic group is a group represented by the following general formula (2).
General formula (2)
-(O-R 7 ) m-
[In the general formula (2), R 7 is an alkylene group having 1 to 3 carbon atoms, and m is an integer of 20 to 30. ]
The fine particle dispersion according to claim 6, wherein R 7 in the general formula (2) is an ethylene group.
The fine particle dispersion according to any one of claims 1 to 7, further comprising a thickener.
The fine particle dispersion according to claim 8, wherein the thickener is diethylene glycol.
The fine particle dispersion according to any one of claims 1 to 9, wherein the fine particles are metal fine particles.
The fine particle dispersion according to any one of Claims 1 to 10, wherein the fine particles are conductive fine particles.
The fine particle dispersion according to claim 11, which is used for forming a wiring pattern.
A wiring pattern formed using the fine particle dispersion according to claim 11.
A method for forming a wiring pattern, comprising: forming a coating film by supplying the fine particle dispersion according to claim 11 to a wiring pattern forming surface; and forming a conductive layer by drying the coating film.
The method for forming a wiring pattern according to claim 14, wherein a method of supplying the fine particle dispersion is an inkjet method.