TW201503163A - Composition for electroconductive film formation and method of forming electroconductive film by using the same - Google Patents

Abstract

The invention provides a composition for electroconductive film formation, which can form an electroconductive film exhibiting excellent conductivity, and a change of a line width is suppressed. The composition for electroconductive film formation is characterized by including copper particles, copper oxide particles, and an organic compound having two or more functional groups selected from a group consisted of an amino group and a hydroxyl group in one molecule, and at least one of the functional groups is an amino group.

Description

Conductive film forming composition and method of producing conductive film using the same

The present invention relates to a composition for forming a conductive film. More specifically, the present invention relates to a conductive film-forming composition containing copper particles, copper oxide particles, and an organic compound having a specific two or more functional groups.

A method of forming a metal film on a substrate is known in which a dispersion of metal particles or metal oxide particles is applied onto a substrate by a printing method, followed by heat treatment to be sintered, thereby forming a metal film or a circuit. An electrical conduction portion such as a wiring in the substrate.

With the existing use of high heat. Compared with the wiring process of vacuum process (sputtering) or plating process, the method is simple. Energy saving. Saving resources, so in the next generation of electronics (electronics) development is expected.

For example, Patent Document 1 discloses a conductive metal paste for filling holes, which is a conductive metal paste containing a metal filler and metal oxide ultrafine particles dispersed in a dispersion medium, wherein the paste contains carbon atoms. The polyol and the polyether compound of 10 or less, the content ratio of the metal filler to the metal oxide ultrafine particles is 10 parts by mass to 1000 parts by mass per 100 parts by mass of the metal oxide ultrafine particles, and the average particle diameter of the metal filler is 0.5 μm to 20 μm, the average particle diameter of the metal oxide ultrafine particles is 200 nm or less, and the metal oxide is reduced to a metal component by heating, and the shear rate measured by a Cone plate type rotational viscometer is 10 s. ^{At -1} , the viscosity at 25 ° C is 50 Pa. s above.

Further, for example, Patent Document 2 discloses a metal ink including There is at least one oxide of 100 nm or less selected from the group consisting of metal oxide nanoparticles and a metal partial polycondensation oxide, and metal nanoparticles of 100 nm or less, and the oxide and the metal nanoparticle are completely isolated and dispersed in a solvent. Also disclosed is that copper (Cu) oxide can be used as the metal oxide nanoparticle; copper (Cu) can be used as the metal nanoparticle; and further, an alkylamine can be contained as a dispersing agent.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent No. 4804083

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-515023

On the other hand, in recent years, in order to cope with the demand for miniaturization and high functionality of electronic devices, wiring has been further refined and integrated in a printed wiring board or the like. Further, it is required to form a conductive film which exhibits excellent conductivity on a substrate.

The inventors of the present invention have attempted to form a conductive film by using the polyether compound described in Patent Document 1 to prepare a conductive film, and as a result, it has been found that there is a problem that the viscosity of the film is lowered at a high temperature required for film formation, and laterally Flow, so the line Wide expansion. Moreover, the inventors of the present invention attempted to form a conductive film by using the alkylamine described in Patent Document 2 to prepare a conductive film-forming composition, and as a result, the required conductivity was not achieved. Therefore, in the prior art, it is impossible to form a conductive film which exhibits excellent conductivity and suppresses variations in line width at the time of film formation.

Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a form which can be formed A composition for forming a conductive film of a conductive film which exhibits excellent conductivity and suppresses a change in line width at the time of film formation.

Moreover, an object of the present invention is to provide a method for producing a conductive film using the conductive film-forming composition.

The present inventors have conducted active research on the problems of the prior art, and have found that the composition for forming a conductive film contains copper particles, copper oxide particles, and a group selected from the group consisting of an amine group and a hydroxyl group in one molecule. The above problem can be solved by an organic compound having two or more functional groups and at least one of which is an amine group.

That is, it was found that the object can be achieved by the following constitution.

(1) A composition for forming a conductive film, comprising copper particles, copper oxide particles, and two or more functional groups selected from the group consisting of an amine group and a hydroxyl group in one molecule, and At least one or more of them are organic compounds of an amine group.

(2) The composition for forming a conductive film according to (1), wherein a mass ratio of the copper particles to the copper oxide particles (total mass of the copper particles/total mass of the copper oxide particles) is 0.3 or more.

(3) The composition for forming a conductive film according to (1) or (2), wherein the copper oxide particles have an average particle diameter of from 1 nm to 100 nm.

The composition for forming a conductive film according to any one of the above aspects, wherein the copper particles have an average particle diameter of 0.5 μm to 9 μm.

(5) The composition for forming a conductive film according to any one of (1) to (4) wherein the organic compound contains an amine group and a hydroxyl group.

(6) The composition for forming a conductive film according to any one of (1) to (5) wherein the organic compound contains a primary amine group.

(7) The composition for forming a conductive film according to any one of (1) to (6), wherein a mass ratio of the organic compound to the copper oxide particles (total mass of the organic compound / total mass of the copper oxide particles) It is 2.0 or less.

The composition for forming a conductive film according to any one of (1) to (7), further comprising a solvent.

(9) A method of producing a conductive film, comprising: a coating film forming step of forming a conductive film forming composition according to any one of (1) to (8) onto a substrate to form a coating film; And a conductive film forming step of forming a conductive film containing metal copper by subjecting the coating film to heat treatment and/or light irradiation treatment.

According to the present invention, it is possible to provide a conductive film-forming composition which can form a conductive film which exhibits excellent conductivity and which suppresses variations in line width at the time of film formation.

Further, according to the present invention, it is also possible to provide a guide using the composition for forming a conductive film. A method of manufacturing an electric film.

Hereinafter, preferred embodiments of the conductive film-forming composition and the method for producing a conductive film of the present invention will be described in detail.

First, the feature points of the present invention which are compared with the prior art will be described in detail.

As described above, the conductive film-forming composition contains two or more functional groups selected from the group consisting of an amine group and a hydroxyl group in one molecule, and at least one of them is contained in one molecule. An organic compound which is an amine group (hereinafter sometimes referred to as "specific organic compound"). Since the specific organic compound contains an amine group and promotes aggregation of the copper oxide particles, it is possible to suppress a change in line width when the composition is heated to a high temperature during sintering. Further, both the amine group and the hydroxyl group promote the reduction of copper oxide during sintering, and therefore, by containing these groups, the conductivity of the formed conductive film can be improved.

In the following, various components (such as copper particles, copper oxide particles, and specific organic compounds) of the conductive film-forming composition will be described in detail, and then a method for producing the conductive film will be described in detail.

<copper particles>

Copper particles are contained in the composition for forming a conductive film. The copper particles and the copper oxide of the copper oxide particles described below form the metallic copper in the conductive film together with the metal copper produced by the heat treatment at the time of film formation or the light irradiation treatment.

The average particle diameter of the copper particles is not particularly limited, and is preferably a particle size, and more It is preferably in the range of 0.5 μm to 9 μm, more preferably in the range of 0.5 μm to 5.0 μm, still more preferably in the range of 0.5 μm to 1.5 μm.

When the average particle diameter is 0.5 μm or more, the conductive film obtained is further excellent in conductivity, which is preferable. Moreover, when the average particle diameter is 9 μm or less, the fine wiring is further facilitated, which is preferable.

As the copper particles, a public used in the composition for forming a conductive film can be used. Known metal copper particles. For example, as the copper particles, wet copper powder 1020Y, wet copper powder 1030Y, wet copper powder 1050Y, wet copper powder 1100Y, and the like manufactured by Mitsui Metals Mining Co., Ltd. can be used.

Further, the average particle diameter in the present invention means an average primary particle diameter. Average grain The diameter is measured by a transmission electron microscope (TEM) or a scanning electron microscope (SEM), and the particle diameter (diameter) of at least 50 or more copper particles is measured, and the particle diameters are measured. Calculated by arithmetic averaging. In the observation chart, when the shape of the copper particles is not a perfect circular shape, the long diameter is measured as the diameter.

<Copper oxide particles>

The composition for forming a conductive film contains copper oxide particles. The copper oxide of the copper oxide particles is reduced to metallic copper by heat treatment or light irradiation treatment at the time of film formation, and together with the copper particles, metal copper in the conductive film is formed.

The average particle diameter of the copper oxide particles is not particularly limited, and is preferably a nano particle. The size is more preferably in the range of 1 nm to 100 nm, and further preferably 1 nm to 80 nm. In the range of 1 nm to 50 nm, it is more preferably in the range of 1 nm to 50 nm.

When the average particle diameter is 1 nm or more, the activity on the surface of the particles does not become excessively high, and dispersion in the composition is easy, and workability and storage stability are excellent, which is preferable. In addition, when the average particle diameter is 100 nm or less, when the composition is conductively film-formed (conductorized), since the active surface is enlarged, it is easily reduced to metallic copper, and the sintering time is shortened, and copper particles are likely to be fused together. Therefore, the conductivity of the obtained conductive film becomes good, which is preferable.

The so-called "copper oxide" in the present invention is substantially free of unoxidized The compound of copper specifically refers to a compound which detects a peak derived from copper oxide in crystal analysis by X-ray diffraction and does not detect a peak derived from a metal. The term "containing substantially no copper" means that the content of copper is 1% by mass or less based on the total mass of the copper oxide particles.

Further, the copper oxide is preferably copper (I) oxide or copper (II) oxide, which is inexpensive. Further, in terms of availability and high stability, copper (II) oxide is further preferred.

As the copper oxide particles, those used in the composition for forming a conductive film can be used. Known copper oxide particles. For example, as the copper oxide particles, CuO nano particles manufactured by Kanto Chemical Co., Ltd., CuO nano particles manufactured by Sigma-Aldrich Co., Ltd., or the like can be used.

Further, the average particle diameter in the present invention means an average primary particle diameter. Average grain The diameter is measured by transmission electron microscope (TEM) observation or scanning electron microscope (SEM), and the particle diameter (diameter) of at least 50 or more copper oxide particles or copper particles is measured, and the particle diameters are arithmetically averaged. Find out. Furthermore, in the observation chart, When the shape of the copper oxide particles is not a perfect circular shape, the long diameter is measured as the diameter.

<specific organic compounds>

The conductive film-forming composition contains an organic compound (specific organic compound) having two or more functional groups selected from the group consisting of an amine group and a hydroxyl group in one molecule, and at least one of which is an amine group. . The specific organic compound is a reducing agent, and the copper oxide is reduced by heat treatment or light irradiation treatment at the time of film formation. The metal copper formed by reduction of copper oxide promotes fusion between copper particles.

In order to further improve the reduction ability of copper oxide, specific organic compounds It preferably contains an amine group and a hydroxyl group. By further increasing the reducing ability of the copper oxide particles, the conductivity of the obtained conductive film becomes more excellent.

The amine group may be any of a primary amine group, a secondary amine group, and a tertiary amine group. Preferably, it is a primary amine group. By further improving the reducing ability to copper oxide, the conductivity of the obtained conductive film becomes more excellent. Moreover, the effect of agglomerating the copper oxide particles is further enhanced, and the effect of suppressing the change in the line width at the time of film formation is more excellent.

The specific organic compound preferably contains one or more molecules per molecule. The amine group and one or more hydroxyl groups are more preferably one or more amine groups and two or more hydroxyl groups in one molecule, and more preferably one or more primary amine groups and two or more molecules in one molecule. The hydroxy group.

As a preferable example of the specific organic compound, the following formula (I) can be cited. Represented.

In the formula (I): R ¹ and R ² are each independently a substituent selected from the group consisting of a hydrogen atom and an alkyl group, and one or more hydrogen atoms of the alkyl group may be optionally substituted by a hydroxyl group or an amine group. One or more -CH ₂ - groups which are not adjacent to N may be subjected to an -O- group or a -NR- group under the condition that the adjacent -CH ₂ - groups are not simultaneously substituted (wherein R is a hydrogen atom) Or an alkyl group optionally substituted; L is a n+1 valent linking group; B is independently a hydroxyl group or an amine group in the presence of a plurality of cases; and n is a natural number.

R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and the hydrogen atom of the alkyl group may be via a hydroxyl group, a —NH ₂ group, an —NHCH ₃ group or a —N(CH ₃ ) group. ₂ bases are optionally substituted.

L is preferably an n+1-valent linking group obtained by removing n+1 hydrogen atoms from a linear or branched alkane having a carbon number of m.

Where m and n are natural numbers satisfying m≧(n-1)/2.

Further, the -CH ₂ - group in L may be optionally substituted with an -O- group or a -NR- group (wherein R is a hydrogen atom or an alkyl group).

Preferable examples of the specific organic compound include those represented by the following formula (II).

In the formula (II): R ¹ and R ² are each independently a substituent selected from the group consisting of a hydrogen atom and an alkyl group, and one or more hydrogen atoms of the alkyl group may be optionally substituted with a hydroxyl group or an amine group. One or more -CH ₂ - groups which are not adjacent to N may be subjected to an -O- group or a -NR- group under the condition that the adjacent -CH ₂ - groups are not simultaneously substituted (wherein R is a hydrogen atom) Or an alkyl group optionally substituted; and R ³ , R ⁴ and R ⁵ are each independently a substituent selected from the group consisting of a hydrogen atom, an alkyl group, a hydroxyl group and an amine group, and one or more hydrogen atoms of the alkyl group; Any one or more of the -CH ₂ - groups of the alkyl group may be subjected to a -O- group or a -NR- group under the condition that the adjacent -CH ₂ - group is not simultaneously substituted. , R is a hydrogen atom or an alkyl group) is optionally substituted.

R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and the hydrogen atom of the alkyl group may be via a hydroxyl group, a —NH ₂ group, an —NHCH ₃ group or a —N(CH ₃ ) group. ₂ bases are optionally substituted.

R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, a —NH ₂ group, an —NHCH ₃ group or a —N(CH ₃ ) ₂ group, and an alkane. The hydrogen atom of the group may be optionally substituted with a hydroxyl group, a -NH ₂ group, an -NHCH ₃ group or a -N(CH ₃ ) ₂ group.

Specific examples of the specific organic compound include, for example, those disclosed below.

Preferred examples of the specific organic compound include 3-amino-1,2-propanediol, 3-methylamino-1,2-propanediol, and 2,2'-oxybis(ethylamine). Of these, 3-amino-1,2-propanediol is particularly preferred.

<solvent>

The composition for forming a conductive film may further contain a solvent. The solvent is, for example, one selected from the group consisting of water, alcohols, ethers, esters, hydrocarbons, and aromatic hydrocarbons, or a mixture of two or more kinds having compatibility.

As a solvent, it is excellent in compatibility with a specific organic compound. In particular, water, a water-soluble alcohol, an alkyl ether derived from the water-soluble alcohol, an alkyl ester derived from the water-soluble alcohol, or a mixture thereof may be preferably used.

As the water, it is preferred to have a purity of at least ion-exchanged water. The water-soluble alcohol is preferably an aliphatic alcohol containing a monovalent to trivalent hydroxy group, and specific examples thereof include methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol. , cyclohexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-nonanol, glycidol, methylcyclohexanol, 2-methyl-1-butanol, 3-methyl-2 -butanol, 4-methyl-2-pentanol, isopropanol, 2-ethylbutanol, 2-ethylhexanol, 2-octanol, terpineol, dihydroterpineol, 2-methyl Oxyethanol, 2-ethoxyethanol, 2-n-butoxyethanol, carbitol, ethyl carbitol, n-butyl carbitol, diacetone alcohol, ethylene glycol, diethylene glycol, three Ethylene glycol, tetraethylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 - pentanediol, hexanediol, glycerol, and the like.

In particular, the aliphatic alcohol having a carbon number of 1 to 6 carbon atoms having a hydroxyl group of 1 to 3 valences is not excessively high in boiling point and is not likely to remain after formation of the conductive film, and is more preferably, more preferably, methanol. Ethylene glycol, glycerin, 2-methoxyethanol, diethylene glycol, isopropanol.

Examples of the ethers include alkyl ethers derived from the alcohols, and examples thereof include diethyl ethers. Ether, diisobutyl ether, dibutyl ether, methyl-tert-butyl ether, methylcyclohexyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, three Ethylene glycol diethyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, and the like. Among them, it is preferably a carbon number of from 1 to 4 carbon atoms derived from a hydroxyl group having a valence to a valence of 3 to 3, and a carbon number of 8 to 8 The alkyl ether, specifically, more preferably diethyl ether, diethylene glycol dimethyl ether or tetrahydrofuran.

Examples of the esters include alkyl esters derived from the alcohols, and formic acid can be exemplified. Ester, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, γ-butyrolactone, and the like. Among them, an alkyl ester having 2 to 8 carbon atoms derived from an aliphatic alcohol having 1 to 3 valent hydroxyl groups and having a carbon number of 1 to 4 carbon atoms is preferable. More specifically, it is preferably methyl formate. , ethyl formate, methyl acetate.

In the solvent, it is particularly preferable to use the aspect that the boiling point is not too high. Water or a water-soluble alcohol is used as a main solvent. The main solvent is a solvent having the highest content in a solvent.

<Other ingredients>

The conductive film-forming composition may contain other components in addition to copper particles, copper oxide particles, specific organic compounds, and a solvent.

For example, a surfactant, a thixotropic agent, a thermoplastic resin (polymer binder), or the like may be contained in the conductive film-forming composition.

The surfactant acts to increase the dispersibility of the copper oxide particles. The type of the surfactant is not particularly limited, and examples thereof include an anionic surfactant, a cationic surfactant, a nonionic surfactant, a fluorine-based surfactant, and an amphoteric surfactant. These surfactants may be used alone or in combination of two or more.

The thixotropic agent imparts thixotropy to the composition for forming a conductive film, and prevents dripping before drying of the composition for forming a conductive film coated or printed on the substrate. By this, it can be avoided The fine patterns are in contact with each other. The thixotropic agent is a known thixotropic agent (thixotropy imparting agent) for a conductive film-forming composition containing a solvent, and does not adversely affect the adhesion and conductivity of the obtained conductive film. There is no particular limitation, and an organic thixotropic agent is preferred.

Examples of the thermoplastic resin (polymer binder) include an acrylic resin, a polyester resin, a polyolefin resin, a polyurethane resin, a polyamide resin, a rosin compound, and a vinyl polymer. These may be used alone or in combination of two or more.

[Conductive film forming composition]

The conductive film-forming composition contains copper particles, copper oxide particles, a specific organic compound, a solvent required, and other components as required.

The ratio (W _A /W _B ) of the total mass (W _A ) of the copper particles in the conductive film-forming composition to the total mass (W _B ) of the copper oxide particles is not particularly limited, but is preferably 0.3 or more. It is preferably in the range of 0.3 to 10, more preferably in the range of 1.0 to 10, and still more preferably in the range of 2.0 to 5.0. When it is in this range, the conductivity of the obtained conductive film is more excellent, and the change in line width is also small.

The ratio (W _C /W _B ) of the total mass (W _C ) of the specific organic compound in the composition for forming a conductive film to the total mass (W _B ) of the copper oxide particles is not particularly limited, but is preferably 2.0 or less. More preferably, it is in the range of 0.1 to 2.0, further preferably in the range of 0.1 to 1.5, and still more preferably in the range of 0.1 to 1.0.

The specific organic compound functions as a reducing agent for reducing copper oxide to metallic copper, and promotes melting of copper particles derived from copper oxide particles and/or copper particles. The organic compound accelerates the aggregation of the copper oxide particles in the composition for forming a conductive film to densify the metal copper formed by the reduction of the copper oxide, thereby improving the compactness of the entire conductive film containing the copper particles.

When W _C /W _B is 2.0 or less, the effect is excellent, and the effect of suppressing the change in the line width at the time of film formation is further excellent.

In addition, when W _C /W _B is 0.1 or more, the conductivity of the conductive film which is excellent in the effect and formed into a film is further excellent.

When the composition for forming a conductive film contains a solvent, the content of the solvent The total mass of the conductive film-forming composition is preferably from 10% by mass to 60% by mass, and more preferably 20% by mass, from the viewpoint of suppressing the increase in the viscosity and the operability. 50% by mass.

The viscosity of the composition for forming a conductive film is preferably adjusted to be suitable for inkjet or mesh Viscosity for printing applications such as printing. In the case of performing ink ejection, it is preferably 1 cP to 50 cP, more preferably 1 cP to 40 cP. In the case of screen printing, it is preferably from 1000 cP to 100,000 cP, more preferably from 10,000 cP to 80,000 cP.

The method for preparing the conductive film-forming composition is not particularly limited and may be employed. A well-known method. For example, after adding copper particles, copper oxide particles, and specific organic compounds to a solvent, a known method such as an ultrasonic method (for example, treatment using an ultrasonic homogenizer), a mixer method, a three-roll method, or a ball mill method is known. Means disperse the ingredients, whereby a composition can be obtained.

[Method of Manufacturing Conductive Film]

The method for producing a conductive film of the present invention includes at least a coating film forming step and a conductive film Forming steps. Hereinafter, each step will be described in detail.

(coating film forming step)

This step is a step of applying the composition for forming a conductive film to a substrate to form a coating film. By this step, the precursor film before the calcination treatment can be obtained.

The composition for forming a conductive film to be used is as described above.

As the substrate used in this step, a known substrate can be used. As a base Examples of the material used in the material include resin, paper, glass, quartz, lanthanide semiconductor, compound semiconductor, metal oxide, metal nitride, wood, or a composite thereof.

More specifically, low density polyethylene resin, high density polyethylene resin, acrylonitrile butadiene styrene (ABS) resin, acrylic resin, styrene resin, vinyl chloride resin, polyester resin Resin substrate such as (polyethylene terephthalate), polyacetal resin, polyfluorene resin, polyether oxime resin, polyether ketone resin, cellulose derivative; non-coated printing paper, micro coating Printing paper, coated printing paper (art paper, coated paper), special printing paper, photocopying paper (plain paper copier (PPC) paper), unbleached wrapping paper ( Unbleached wrapping paper) (unglazed shipping sacks kraft paper, kraft paper), bleached wrapping paper (bleached kraft paper), pure white reel Paper substrate such as paper (pure white roll paper), coated board, chipboard, cardboard, soda glass, borosilicate glass, cerium oxide glass, Glass substrate such as quartz glass; lanthanide semiconductor substrate such as amorphous silicon or polysilicon; compound semiconductor substrate such as CdS, CdTe, GaAs; metal substrate such as copper plate, iron plate or aluminum plate; , sapphire, zirconia, titania, yttria, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), Nesse (NESA) (tin oxide), doped Anthony-doped tin oxide (ATO), fluorine-doped tin oxide, zinc oxide, aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide, aluminum nitride substrate, Other inorganic substrates such as niobium carbide; paper-resin composites such as paper-phenol resin, paper-epoxy resin, paper-polyester resin, glass cloth-epoxy resin, glass cloth-polyimine resin, glass cloth - A composite substrate such as a glass-resin composite such as a fluororesin. Among these substrates, a polyester resin substrate, a polyether phthalimide resin substrate, a paper substrate, and a glass substrate are preferably used.

There is no special method for imparting a composition for forming a conductive film to a substrate. For the limitation, a known method can be employed. For example, a coating method such as a bar coating method, a screen printing method, a dip coating method, a spray coating method, a spin coating method, or an inkjet method can be mentioned.

The shape to be applied is not particularly limited, and may be a planar shape covering the entire surface of the substrate, or may be a pattern (for example, a wiring shape or a dot shape).

The coating amount of the conductive film-forming composition on the substrate may be appropriately adjusted depending on the film thickness of the conductive film to be used. Usually, the film thickness of the coating film is preferably from 0.01 μm to 5000 μm, more preferably 0.1 μm. 1000 μm.

In this step, if necessary, a composition for forming a conductive film can be applied onto a substrate, followed by drying treatment to remove the solvent. By removing the remaining solvent, after In the conductive film forming step, it is preferable to suppress occurrence of minute cracks or voids caused by vaporization expansion of the solvent, and it is preferable in terms of conductivity of the conductive film and adhesion between the conductive film and the substrate.

The drying treatment method may use a warm air dryer or the like as a temperature, preferably In order to prevent the reduction of the copper oxide particles from occurring, it is preferably heat-treated at 40 ° C to 200 ° C, more preferably at 50 ° C or higher and less than 150 ° C, and more preferably at 70 ° C. Heat treatment was carried out at 120 °C.

(Conductive film forming step)

In this step, the coating film formed in the coating film forming step is subjected to heat treatment and/or light irradiation treatment to reduce copper oxide and/or copper oxide on the surface of the copper particles in the copper oxide particles to form a conductive metal containing copper. The step of the membrane.

Specific organic compounds are prepared by heat treatment and/or light irradiation treatment The copper oxide and/or the reducing agent of copper oxide on the surface of the copper particles acts to reduce the copper oxide and further sinter to obtain metallic copper. More specifically, by performing the treatment, the metallic copper particles in the coating film are fused to each other to form a grain, and the particles are bonded to each other. Melting to form a copper film.

The conditions of the heat treatment depend on the type of copper complex or solvent used. And choose the best conditions. In particular, in the case where a conductive film having more excellent conductivity can be formed in a short time, the heating temperature is preferably from 100 ° C to 300 ° C, more preferably from 120 ° C to 250 ° C, and further, the heating time is preferably one minute. ~120 minutes, more preferably 5 minutes to 60 minutes.

Further, the heating device is not particularly limited, and an oven, a heating plate, or the like can be used. Heating device.

In the present invention, the conductive film can be formed by a relatively low-temperature heat treatment, and therefore, there is an advantage that the process cost is low.

The light irradiation treatment is different from the heat treatment by being able to be treated at room temperature The portion to which the coating film is applied is irradiated with light for a short period of time to reduce and sinter the copper oxide, and deterioration of the substrate due to heating for a long period of time does not occur, and the adhesion between the conductive film and the substrate is further improved. Further, when light irradiation is performed, the copper oxide particles absorb light and are converted into heat, and the heat promotes reduction of copper oxide by a specific organic compound as a reducing agent, and fusion of the formed metal copper is performed. .

The light source used in the light irradiation treatment is not particularly limited, and for example, there is: mercury Lamps, metal halide lamps, xenon lamps, chemical lamps, carbon arc lamps, etc. Radiation: electron beam, X-ray, ion beam, far infrared, etc. Further, g-rays, i-rays, deep ultraviolet light (Deep-UV light), and high-density energy beams (laser beams) are also used. Specific examples thereof include high-intensity flash exposure by infrared laser scanning exposure, xenon discharge lamp, and the like, and infrared lamp exposure.

Light illumination is preferably illuminated by flash light, preferably by flash Pulsed light illumination. Since the irradiation of the high-energy pulsed light is concentrated and heated in a very short time on the surface of the portion to which the coating film is applied, the influence of heat on the substrate can be minimized.

The irradiation energy of the pulse light is preferably ^{1J / cm 2 ~ 100J / cm} 2, more preferably ^{1 J / cm 2 ~ 30J /} cm 2, the pulse width is preferably 1μs ~ 100ms, more preferably 10μs ~ 10ms. The irradiation time of the pulsed light is preferably from 1 ms to 100 ms, more preferably from 1 ms to 50 ms, and further preferably from 1 ms to 20 ms.

The heat treatment and the light irradiation treatment may be performed separately, or two Implemented at the same time. Further, after performing one of the processes, another process may be performed. In the case of separate implementation, it is preferred to carry out the heat treatment separately.

The gas environment in which the heat treatment and the light irradiation treatment are carried out is not particularly The restrictions include, for example, an atmospheric environment, an inert gas atmosphere, or a reducing gas atmosphere. In addition, the inert gas atmosphere is, for example, a gas atmosphere filled with an inert gas such as argon gas, helium gas, neon gas or nitrogen gas, and the so-called reducing gas atmosphere means a gas atmosphere in which a reducing gas such as hydrogen or carbon monoxide is present. .

(conductive film)

By carrying out the above steps, a conductive film (metal copper film) containing metallic copper is obtained.

The film thickness of the conductive film is not particularly limited, and an optimum film thickness is appropriately adjusted depending on the use used. Among them, from the viewpoint of the use of the printed wiring board, it is preferably from 0.01 μm to 1000 μm, more preferably from 0.1 μm to 100 μm. In addition, the film thickness is a value (average value) obtained by measuring the thickness of any point of the conductive film at three or more places and arithmetically averaging the values.

The volume resistance value can be calculated by measuring the surface resistance value of the conductive film by the four-probe method and multiplying the obtained surface resistance value by the film thickness.

The conductive film may be provided on the entire surface of the substrate or in a pattern. The patterned conductive film is useful as a conductor wiring (wiring) such as a printed wiring board.

In the method of obtaining the patterned conductive film, the conductive film forming composition is applied to the substrate as a pattern, and the heat treatment and/or the heat treatment is performed. A method of light irradiation treatment; or a method of etching a conductive film provided on the entire surface of a substrate into a pattern. The etching method is not particularly limited, and a known subtractive method, semi-adhesive method, or the like can be employed.

When the patterned conductive film is configured as a multilayer wiring substrate, Further, an insulating layer (an insulating resin layer, an interlayer insulating film, and a solder resist layer) is laminated on the surface of the patterned conductive film, and further wiring (metal pattern) is formed on the surface.

The material of the insulating film is not particularly limited, and examples thereof include epoxy resins. Polyarylamine resin, crystalline polyolefin resin, amorphous polyolefin resin, fluorine-containing resin (polytetrafluoroethylene, perfluoropolyimine, perfluorinated amorphous resin, etc.), polyimine resin , polyether oxime resin, polyphenylene sulfide resin, polyether ether ketone resin, liquid crystal resin, and the like. Among these, from the viewpoints of adhesion, dimensional stability, heat resistance, electrical insulation, and the like, it is preferably an epoxy resin, a polyimide resin, or a liquid crystal resin, and more preferably an epoxy resin. Specifically, ABF GX-13 manufactured by Ajinomoto Fine-Techno Co., Ltd., and the like can be mentioned.

Moreover, the solder resist as one of the materials for protecting the insulating layer of the wiring The agent can be applied to the present invention as needed, for example, in Japanese Patent Application Laid-Open No. Hei 10-204150, or JP-A-2003-222993. A commercially available product can be used as the solder resist. Specific examples thereof include PFR800, PSR4000 (trade name) manufactured by Taiyo Ink Co., Ltd., and SR7200G manufactured by Hitachi Chemical Co., Ltd.

A substrate having the obtained conductive film (a substrate with a conductive film) is available For a variety of uses. For example, a printed wiring board and a thin film transistor (Thin Film) Transistor (TFT), Flexible Print Circuit (FPC), Radio Frequency Identification (RFID), and the like.

[Examples]

<Example 1>

(Preparation of conductive ink composition)

Copper particles (manufactured by Mitsui Metals, Inc., 1100Y; average particle diameter: 1.1 μm) (50 parts by mass), copper oxide particles (manufactured by Kanto Chemical Co., Ltd., CuO nanoparticles; average particle diameter: 50 nm) (50 parts by mass), 3- Amino propylene glycol (the following formula) (12 parts by mass) and pure water (82 parts by mass) were mixed, and dispersed in a ritual (2200 rpm, 3 minutes) to prepare a composition for forming a conductive film.

(Manufacture of conductive film)

The prepared conductive film forming composition was applied to a glass substrate by screen printing with a film of 10 mm × 10 mm and a thin line having a width of 200 μm, a length of 30 mm, and a film thickness of 40 μm. After heating and drying at 50 ° C for 10 minutes, it was calcined at 300 ° C for 10 minutes under an argon atmosphere to obtain a conductive film.

<Example 2>

The amount of 3-aminopropanediol was changed from 12 parts by mass to 24 parts by mass, except In the same manner as in Example 1, a conductive film-forming composition was prepared to form a conductive film.

<Example 3>

In the same manner as in Example 1, except that the amount of the copper particles was changed from 50 parts by mass to 200 parts by mass, a conductive film was formed in the same manner as in Example 1.

<Example 4>

In the same manner as in Example 1, except that the amount of the copper particles was changed from 50 parts by mass to 10 parts by mass, a conductive film was formed in the same manner as in Example 1.

<Example 5>

Copper particles (manufactured by Mitsui Metals, Inc., 1020Y; average particle diameter: 0.37 μm) were used instead of copper particles (manufactured by Mitsui Metals, Inc., 1100Y; average particle diameter: 1.1 μm), except that this was prepared in the same manner as in Example 1. A conductive film is formed by a composition for forming a conductive film.

<Example 6>

In place of copper particles (manufactured by Mitsui Metals Co., Ltd., 1100Y; average particle diameter: 1.1 μm), copper particles (manufactured by Nippon Atomized Processing Corporation, AFS Cu; average particle diameter: 7 μm) were used, in addition to this, In the same manner as in Example 1, a conductive film forming composition was prepared to form a conductive film.

<Example 7>

Use of copper particles (made by ALDRICH, 326453; flat In the same manner as in Example 1, except that the copper particles (average particle diameter: 10 μm) were used instead of the copper particles (manufactured by Mitsui Metals Co., Ltd., 1100Y; average particle diameter: 1.1 μm), a conductive film was formed in the same manner as in Example 1.

<Example 8>

A conductive film was formed in the same manner as in Example 1 except that 3-methylamino-1,2-propanediol (the following formula) was used instead of 3-aminopropanediol.

<Example 9>

A conductive film was formed in the same manner as in Example 1 except that 2,2'-oxybis(ethylamine) (the following formula) was used instead of 3-aminopropanediol.

<Example 10>

The amount of 2,2'-oxybis(ethylamine) was changed from 12 parts by mass to 24 parts by mass, except In the same manner as in Example 9, a conductive film forming composition was prepared to form a conductive film.

<Example 11>

A conductive film was formed in the same manner as in Example 1 except that the amount of the 3-aminopropanediol was changed from 12 parts by mass to 120 parts by mass.

<Comparative Example 1>

A conductive film was formed in the same manner as in Example 1 except that 1-octylamine (the following formula) was used instead of 3-aminopropanediol.

<Comparative Example 2>

A conductive ink composition was prepared in the same manner as in Example 1 except that the copper oxide particles were not used, and a conductive film was formed.

<Comparative Example 3>

A conductive ink composition was prepared in the same manner as in Example 1 except that copper particles were not used, and a conductive film was formed.

<Comparative Example 4>

A lead was prepared in the same manner as in Example 1 except that poly(ethylene oxide) (PEO 600, number average molecular weight 600) was used instead of 3-aminopropylene glycol. The electroless ink composition forms a conductive film.

<Electrical conductivity>

The electrical conductivity of the conductive films of Examples 1 to 11 and Comparative Examples 1 to 4 was evaluated by the following methods.

Regarding the obtained conductive film (entire film portion), the volume resistance value was measured using a four-probe method resistivity meter. The measured volume resistance values are shown in the corresponding columns of Table 1. Furthermore, OVLD indicates outside the range of the measurement range.

<change in line width>

The change in line width before and after firing of the conductive films of Examples 1 to 11 and Comparative Examples 1 to 4 was evaluated by the following method.

The line width of the obtained conductive film (thin line portion) was measured with an optical microscope, and the change in line width before and after the calcination was evaluated. The evaluation criteria are as follows according to the rate of change (absolute value) of the line width. Practically, it is ideally A.

A...The rate of change of the line width (absolute value) is 5% or less

B... The rate of change of the line width (absolute value) exceeds 5% and is 10% or less.

C... line rate of change (absolute value) exceeds 10%

The evaluation of the measured line width and line width change is shown in the corresponding column of Table 1.

Comparative Example 1 is a comparative example in which 1-octylamine was used instead of 3-aminopropanediol. 1-octylamine is a compound containing one amine group in one molecule, and has a lower ability to reduce copper oxide than 3-aminopropylene glycol having one amine group and two hydroxyl groups in one molecule. Therefore, it is considered that Comparative Example 1 is inferior to Example 1 in terms of electrical conductivity.

Comparative Example 2 is a comparative example containing no copper oxide particles. In the case where the copper oxide particles are not contained, the copper particles are not promoted to each other as compared with the case where the copper oxide particles are contained. Therefore, it is considered that Comparative Example 2 is inferior to Example 1 in terms of electrical conductivity. Also, since a specific organic compound suppresses line width by promoting aggregation of copper oxide particles In the case where the copper oxide particles are not contained, it is considered that the change in the line width at the time of film formation is larger than in the case of containing the copper oxide particles.

Comparative Example 3 is a comparative example containing no copper particles. In the case of copper-free particles At the time, the conductive film could not be sufficiently formed as compared with the case of containing copper particles. Therefore, it is considered that Comparative Example 3 is inferior to Example 1 in terms of conductivity.

Comparative Example 4 is a comparative example in which PEO600 was used instead of 3-aminopropanediol. Since PEO600 contains a hydroxyl group in one molecule, the ability to reduce copper oxide is high, but since it does not contain an amine group, it is considered that the effect of promoting aggregation of copper oxide particles is low. Therefore, it is considered that although the conductivity is excellent, the change in the line width at the time of film formation is large.

Example 11 is a specific organic compound (3-amino group) as compared with Example 1. Examples of a high content of propylene glycol).

In Example 11 containing 120 parts by mass of 3-aminopropanediol with respect to 50 parts by mass of the copper oxide particles, the change in line width was not suppressed as compared with Example 1, and the conductivity was also compared with Example 1. reduce.

This indicates that if the ratio (W _C / W _B) of the total mass of the composition with a specific organic compound (W _C) with respect to the total mass (W _B) copper oxide particles formed in the conductive film is 2.0 or less, the The change in line width at the time of film formation is suppressed.

Example 4 is an example in which the mass ratio of copper particles to copper oxide particles is smaller than that of Example 1.

In Example 4 containing 10 parts by mass of copper particles with respect to 50 parts by mass of the copper oxide particles, the change in line width was not suppressed as compared with Example 1, and the conductivity was also lowered as compared with Example 1.

From this, it is understood that the conductivity (W _A /W _B ) of the total mass (W _A ) of the copper particles in the conductive film-forming composition relative to the total mass (W _B ) of the copper oxide particles is 0.3 or more. Excellent, it can suppress the change of the line width at the time of film formation.

In Example 5 and Example 7, the average particle diameter of the copper particles was 0.5. Examples outside the range of μm~9 μm. Further, the copper particles of Example 6 had an average particle diameter of 7 μm, which was larger than that of Example 1, but was in the range of 0.5 μm to 9 μm.

In Example 5 in which the average particle diameter of the copper particles was 0.37 μm, the change in line width was suppressed in the same manner as in Example 1 and Example 6, but the conductivity was lowered as compared with Example 1 and Example 6.

In Example 7 in which the average particle diameter of the copper particles was 10 μm, the change in line width was suppressed in the same manner as in Example 1 and Example 6, but the conductivity was lowered as compared with Example 1 and Example 6.

From these, it is understood that when the average particle diameter of the copper particles is from 0.5 μm to 9 μm, the conductivity is more excellent.

Example 8 is a compound containing a secondary amine group (3-methylamino group) -1,2-propanediol) An example of the compound of the first embodiment having a primary amine group (3-aminopropanediol).

In Example 8, the change in line width was not suppressed as compared with Example 1, and the conductivity was also lowered as compared with Example 1.

Therefore, when a specific organic compound contains a primary amine group, it is excellent in electroconductivity, and the change of the line width at the time of film formation is also suppressed.

Claims (9)

A composition for forming a conductive film, comprising copper particles, copper oxide particles, and at least one functional group selected from the group consisting of an amine group and a hydroxyl group in one molecule, and at least one of them More than one organic compound which is an amine group. The composition for forming a conductive film according to the first aspect of the invention, wherein the copper oxide particles have an average particle diameter of from 1 nm to 100 nm. The composition for forming a conductive film according to the first aspect of the invention, wherein the copper particles have an average particle diameter of 0.5 μm to 9 μm. The composition for forming a conductive film according to the first aspect of the invention, wherein the mass ratio of the copper particles to the copper oxide particles (total mass of copper particles/total mass of copper oxide particles) is 0.3 or more. The composition for forming a conductive film according to the first aspect of the invention, wherein the mass ratio of the organic compound to the copper oxide particles (total mass of the organic compound / total mass of the copper oxide particles) is 2.0 or less. The composition for forming a conductive film according to the above aspect of the invention, wherein the organic compound contains an amine group and a hydroxyl group. The composition for forming a conductive film according to claim 1, wherein the organic compound contains a primary amine group. The composition for forming a conductive film according to any one of the first to seventh aspects of the present invention, further comprising a solvent. A method of producing a conductive film, comprising: a conductive film shape according to any one of claims 1 to 8 A coating film forming step of forming a coating composition on a substrate to form a coating film; and a conductive film forming step of forming a conductive film containing metal copper by subjecting the coating film to heat treatment and/or light irradiation treatment.