JP7340179B2 - Method for manufacturing a conductor, method for manufacturing a wiring board, and composition for forming a conductor - Google Patents

Description

The present invention relates to a method for manufacturing a conductor, a method for manufacturing a wiring board, and a composition for forming a conductor.

2. Description of the Related Art In recent years, a technology called printable electronics, in which elements and wiring for various electronic devices and electrical equipment are formed by a printing method, has been attracting attention. Conventional methods such as vacuum evaporation, sputtering, and CVD require large-scale equipment, which is a major factor in the high cost of products. In addition, these methods generally involve a step of leaving a portion that will serve as wiring and removing other portions by etching or the like, resulting in problems such as inefficient use of materials and disposal of waste. On the other hand, in printable electronics, a coating liquid containing a wiring material is printed on a substrate and then heat-treated to form wiring. For this reason, it has advantages such as not requiring expensive equipment and not producing waste materials associated with wiring formation.

On the other hand, as wiring materials, the use of metals such as copper and nickel, which are cheaper and do not cause migration, is being considered in place of precious metals such as gold and silver. However, since these metals have the property of being easily oxidized, it is necessary to take measures to prevent oxidation, such as forming wiring under an inert gas atmosphere, and this is one of the factors that hinders cost reduction. It has become.

As a method for suppressing metal oxidation, various methods of coating the surfaces of metal particles with organic or inorganic substances have been studied. For example, Patent Document 1 describes a method of forming a circuit using copper fine particles including a coating layer containing cuprous oxide and a coating layer containing a long-chain aliphatic amine.

Japanese Patent Application Publication No. 2014-1443

In the method described in Patent Document 1, it is necessary to produce copper fine particles having a coating, and there is room for improvement from the viewpoint of cost reduction. Therefore, there is a need to develop a technology that can form a conductor using a simpler method while suppressing oxidation of the metal.

In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a conductor, a method for manufacturing a wiring board, and a composition for forming a conductor, which can form a conductor while suppressing oxidation.

Means for solving the above problems include the following embodiments.
<1> A step of applying a composition containing a nickel complex and a solvent capable of dissolving the nickel complex to a substrate to form a composition layer, and a step of irradiating the composition layer with light to precipitate nickel. and a method for manufacturing a conductor.
<2> The method for manufacturing a conductor according to <1>, further comprising the step of applying metal plating on the precipitated nickel.
<3> The method for manufacturing a conductor according to <1> or <2>, wherein the light irradiation is performed using at least one selected from the group consisting of a CO ₂ laser, an Er laser, a xenon lamp, and an excimer lamp.
<4> The method for manufacturing a conductor according to any one of <1> to <3>, wherein the light irradiation is performed in a pattern.
<5> The method for manufacturing a conductor according to any one of <1> to <4>, which is performed in the atmosphere.
<6> The method for producing a conductor according to any one of <1> to <5>, wherein the nickel complex contains an amine compound as a ligand.
<7> The method for producing a conductor according to any one of <1> to <6>, wherein the nickel complex contains an amino alcohol as a ligand.
<8> The method for producing a conductor according to any one of <1> to <7>, wherein the nickel complex forms a salt soluble in an organic solvent with a counter anion.
<9> The method for manufacturing a conductor according to any one of <1> to <8>, wherein the solvent is an organic solvent.
<10> A method for manufacturing a wiring board comprising a substrate and nickel wiring disposed on the substrate, the method comprising applying to the substrate a composition containing a nickel complex and a solvent capable of dissolving the nickel complex. A method for manufacturing a wiring board, comprising the steps of forming a composition layer, and irradiating the composition layer with light to precipitate nickel.
<11> The method for manufacturing a wiring board according to <10>, further comprising the step of applying metal plating on the precipitated nickel.
<12> The method for manufacturing a wiring board according to <10> or <11>, wherein the light irradiation is performed using at least one selected from the group consisting of a CO ₂ laser, an Er laser, a xenon lamp, and an excimer lamp. .
<13> The method for manufacturing a wiring board according to any one of <10> to <12>, wherein the light irradiation is performed in a pattern.
<14> The method for manufacturing a wiring board according to any one of <10> to <13>, which is performed in the atmosphere.
<15> The method for manufacturing a wiring board according to any one of <10> to <14>, wherein the nickel complex contains an amine compound as a ligand.
<16> The method for manufacturing a wiring board according to any one of <10> to <15>, wherein the nickel complex contains an amino alcohol as a ligand.
<17> The method for manufacturing a wiring board according to any one of <10> to <16>, wherein the nickel complex forms a salt soluble in an organic solvent with a counter anion.
<18> The method for manufacturing a wiring board according to any one of <10> to <17>, wherein the solvent is an organic solvent.
<19> A conductor-forming composition comprising a nickel complex and a solvent capable of dissolving the nickel complex.
<20> The conductor-forming composition according to <19>, wherein the nickel complex contains an amine compound as a ligand.
<21> The conductor-forming composition according to <19> or <20>, wherein the nickel complex contains an amino alcohol as a ligand.
<22> The conductor-forming composition according to any one of <19> to <21>, wherein the nickel complex forms a salt soluble in an organic solvent with a counter anion.
<23> The conductor-forming composition according to any one of <19> to <22>, wherein the solvent is an organic solvent.

According to the present invention, there are provided a method for manufacturing a conductor, a method for manufacturing a wiring board, and a composition for forming a conductor, which can form a conductor while suppressing oxidation.

These are photographs showing the state of electroless copper plating on deposited nickel (left: taken with a digital microscope, right: taken with a laser microscope). These are photographs (left: taken with a digital microscope, right: taken with a laser microscope) showing the state when electroless nickel plating was performed on deposited nickel.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including elemental steps and the like) are not essential unless otherwise specified. The same applies to numerical values and their ranges, and they do not limit the present invention.
In this disclosure, the term "step" includes not only a step that is independent from other steps, but also a step that cannot be clearly distinguished from other steps, as long as the purpose of the step is achieved. .
In the present disclosure, numerical ranges indicated using "~" include the numerical values written before and after "~" as minimum and maximum values, respectively.
In the numerical ranges described step by step in this disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another numerical range described step by step. . Furthermore, in the numerical ranges described in this disclosure, the upper limit or lower limit of the numerical range may be replaced with the values shown in the Examples.
In the present disclosure, each component may contain multiple types of corresponding substances. If there are multiple types of substances corresponding to each component in the composition, the content rate or content of each component is the total content rate or content of the multiple types of substances present in the composition, unless otherwise specified. means quantity.

<Conductor manufacturing method>
The method for manufacturing a conductor of the present disclosure includes a step of applying a composition containing a nickel complex and a solvent capable of dissolving the nickel complex to a substrate to form a composition layer, and irradiating the composition layer with light. and a step of depositing nickel.

In the above method, nickel is precipitated by irradiating the composition layer formed on the substrate with light. Specifically, when light irradiation is performed, the irradiated part is instantaneously heated, and this heat breaks the bonds of the ligands of the nickel complex, reduces the nickel ions, and precipitates nickel. At this time, the ligands constituting the nickel complex are decomposed by heat into CO ₂ , H ₂ O, N _{2 ,} etc., and are removed in the form of a gas, so that a highly pure conductor can be obtained. The shape of the conductor is not particularly limited, and may be film-like, pattern-like, or other shapes.

In the above method, it is thought that the nickel nanoparticles produced by precipitation melt and grow to form a conductor in the light irradiated area. Furthermore, since this reaction proceeds in an extremely short period of time, it is thought that nickel is precipitated and a conductor is formed before it reacts with oxygen. Therefore, it becomes possible to carry out a series of steps in the atmosphere.

Furthermore, because the precipitated nickel nanoparticles melt at a temperature lower than the melting point of nickel due to the so-called size effect, a conductor can be formed with low energy. Furthermore, the composition layer outside the area irradiated with light can be easily removed using a solvent or the like that can dissolve the nickel complex, which is advantageous in terms of cost reduction. Furthermore, by using a solvent that can dissolve the nickel complex in the composition, problems such as aggregation and oxidation do not occur when metal particles are used, and the composition has excellent storage stability.

(nickel complex)
The nickel complex used in the above method is not particularly limited as long as it contains a ligand and a nickel atom, but from the viewpoint of stability, one containing a nitrogen atom-containing ligand is preferable. It is more preferable to use an amine compound. One type of nickel complex may be used alone or two or more types may be used in combination.

Examples of amine compounds as ligands constituting the nickel complex include monoalkylamine compounds such as methylamine and ethylamine, dialkylamine compounds such as diethylamine, trialkylamine compounds such as triethylamine, alkylenediamine compounds such as ethylenediamine, and amino alcohols. Examples include.

In some embodiments, the nickel complex may be two molecules of an alkylenediamine compound coordinated to a nickel atom, or two molecules of ethylenediamine coordinated to a nickel atom (bis(ethylenediamine)nickel(II)). It may be. Note that this nickel complex is soluble in water or alcohol solvent.

In some embodiments, the nickel complex may include an amino alcohol as a ligand. Nickel complexes containing amino alcohols as ligands are soluble in both water and organic solvents.

By making the nickel complex soluble in an organic solvent, it becomes possible to use the organic solvent as a solvent for a composition containing the nickel complex. As a result, a nickel conductor can be formed even on a substrate where it is difficult to form a uniform composition layer due to surface tension when using an aqueous solvent. Therefore, it is suitable for forming a conductor on a water-repellent substrate.

From the viewpoint of solubility in the solvent, the number of amino alcohol molecules coordinated to the nickel atom is preferably 4 to 6. The larger the number of amino alcohol molecules coordinated to the nickel atom, the higher the solubility in the solvent tends to be.

Amino alcohol is a compound in which an amino group and a hydroxy group are bonded to an alkane skeleton, and the positions of the amino group and hydroxy group in the alkane skeleton are not particularly limited. Specifically, amino alcohols include 2-aminoethanol, 2-amino-1-propanol, 2-amino-2-methyl-1-propanol, methanolamine, dimethylethanolamine, N-methylethanolamine, propanolamine, etc. Can be mentioned.

In some embodiments, the nickel complex may form a salt with a counteranion. By selecting the type of counter anion that forms a salt with the nickel complex, the nickel complex can be made soluble in an organic solvent. For example, the nickel complex of ethylenediamine, which is soluble in the water or alcohol solvents mentioned above, can be made soluble in a non-polar organic solvent.

The counter anion capable of forming a salt with a nickel complex has a larger molecular weight, from the viewpoint of increasing solubility in an organic solvent.

In one embodiment, the counter anion may be a compound having a hydrocarbon group in its molecule, or a compound having a hydrocarbon group and a halogen atom. Examples of the hydrocarbon group include an alkyl group and an aryl group. The number of carbon atoms in the hydrocarbon group is not particularly limited, but, for example, the number of carbon atoms in the counter anion (the total number when two molecules form a salt) may be 20 or more, or 40 or more. A specific example of the counter anion having a hydrocarbon group and a halogen atom in its molecule is tetraphenylborate ion.

In one embodiment, the salt containing a nickel complex and a counter anion may be a salt containing one molecule of the nickel complex and two molecules of the counter anion.

The content of the nickel complex in the composition is not particularly limited, but may be, for example, in the range of 5% to 90% by mass, preferably in the range of 10% to 80% by mass of the entire composition. .

(solvent)
The solvent contained in the composition is not particularly limited as long as it can dissolve the nickel complex or its salt. The solvent may be water or an organic solvent. Examples of the organic solvent include alcohol solvents such as methanol, ethanol, and aminoethanol, ketone solvents such as cyclohexanone, amide solvents such as dimethylformamide, terpene solvents such as terpineol, and ester solvents. From the viewpoint of less influence on the substrate, affinity for the environment, etc., polar organic solvents are preferred, and alcoholic solvents are more preferred. One type of solvent may be used alone or two or more types may be used in combination.

The boiling point of the solvent is not particularly limited, but the boiling point at atmospheric pressure may be less than 150°C, less than 130°C, or less than 100°C.

The composition may contain components other than the nickel complex and the solvent, if necessary. Such components include viscosity modifiers, colorants, and the like.

The board used in the above method is not particularly limited, and any common wiring board for electronic component devices can be used. Examples include semiconductor substrates, glass substrates, ceramic substrates, resin substrates, and composites thereof. Further examples include substrates used in paper devices using cellulose nanofibers. In the above method, since the conductor is formed by light irradiation, the conductor can be formed even on a substrate made of a material that is not suitable for heat treatment such as firing.

The method of forming the composition layer on the substrate is not particularly limited. Examples include spin coating, printing, and the like. The composition layer may be formed uniformly on the substrate or may be formed in a pattern. The composition layer when irradiated with light may contain a solvent or may be in a state in which it does not contain a solvent (the solvent is volatilized).

The light used for light irradiation in the above method is preferably selected from ultraviolet rays, visible light, infrared rays, and near infrared rays, and is not particularly limited as long as it causes decomposition of the nickel complex and precipitation of nickel. From the viewpoint of forming a good conductor in the atmosphere, the light source is preferably an infrared laser or a near-infrared laser, and more preferably a CO ₂ laser or an Er laser (more specifically, YAG and YVO ₄ ). Furthermore, a xenon lamp and an excimer lamp may be used. The composition layer may be irradiated with light uniformly or in a pattern.

The above method may include a step of removing the composition layer other than the portion where nickel has been precipitated by light irradiation. For example, the composition layer may be removed using a solvent that can dissolve the nickel complex contained in the composition layer.

The nickel conductor obtained by the above method may be further subjected to treatments such as metal plating. The thickness of the conductor can be increased by applying metal plating. The metal used for metal plating is not particularly limited, and examples include copper, nickel, tin, gold, silver, and alloys thereof. Further, nickel may be used as a material for metal plating. The method of metal plating is not particularly limited, and may be electroless plating or electrolytic plating. The plating method is not particularly limited. For example, the composition of the electrolytic plating bath includes a sulfuric acid-based plating bath, an organic acid-based plating bath, and the like.

The nickel conductor obtained by the above method may be used as a catalyst film (base) for depositing metal in metal plating, or nickel alone may be used as a conductor.

The thickness of the film formed on the nickel conductor by metal plating is not particularly limited, and may be selected from the range of 1 μm to 100 μm, for example. The thickness of the film formed by metal plating can be controlled by the conditions under which metal plating is performed.

The above method is suitable for forming a patterned conductor because it is possible to form a conductor with excellent uniformity in pattern width by light irradiation. The method described above makes it possible to form finer patterns than conventional methods, making it possible to provide elements (circuits) and wiring with higher performance.

As a method for forming a patterned conductor, there is also a method of directly irradiating the composition layer with a laser in a pattern to form a nickel conductor in the irradiated area (direct patterning). A method may also be used in which the entire surface is then irradiated with a laser to form a conductor on the nickel. These methods do not require an etching process to remove unnecessary conductors, and are environmentally friendly because they do not generate etching waste liquid. Methods for forming the composition layer in a pattern include printing methods commonly used for forming wiring, such as screen printing and offset printing, as well as microcontact printing, which can form even finer wiring.

As a method for forming a patterned conductor by microcontact printing, for example, a composition adhered to a stamper made of PDMS (polydimethylsiloxane) is transferred onto a substrate to form a patterned composition layer, and then light irradiation is performed. An example of this method is to precipitate nickel.

The conductor formed by the above method can be used for various purposes. For example, it can be suitably used as a method for forming elements or wiring of wiring boards used in electronic devices. Furthermore, since conductors can be formed with low energy, it can be suitably used for forming conductors on substrates, such as resin films, glass thin plates, paper devices, etc., on which it is difficult to form conductors using conventional methods.

One application example of the above method is the formation of through electrodes in an interposer made of glass (glass interposer). An interposer is a member placed between a substrate and a semiconductor element, and includes a through electrode that electrically connects the substrate and the semiconductor element. Resin, silicone, etc. are generally used as the material for the interposer. While glass interposers have advantages over interposers made of resin, silicon, etc. in terms of coefficient of thermal expansion, heat resistance, insulation, manufacturing cost, etc., the problem is that they are not strong enough to withstand the process of forming through electrodes. There is.

According to the above method, the through electrode can be formed without damaging the thin glass plate. Forming a through electrode in a glass interposer is performed, for example, by forming a through hole in a thin glass plate by laser processing, then applying a composition for forming a conductor inside the through hole, and depositing nickel by light irradiation. be able to.

Furthermore, one application example of the above method is the formation of external electrodes or internal electrodes of chip components.
For example, the external electrode of a chip component can be formed by preparing a ceramic laminate on which internal electrodes are formed, applying a conductor-forming composition to the portion of the ceramic laminate where the external electrode is to be formed, and precipitating nickel by irradiating it with light. After that, it can be formed by performing metal plating.
Internal electrodes of chip components can be formed, for example, by applying a conductor-forming composition to the portion of the ceramic green sheet where the internal electrodes are to be formed, precipitating nickel by irradiation with light, and then performing metal plating. Can be done. Note that a chip component can be manufactured by stacking ceramic green sheets on which internal electrodes are formed, firing them, and then forming external electrodes.

<Method for manufacturing wiring board>
A method for manufacturing a wiring board according to the present disclosure is a method for manufacturing a wiring board comprising a substrate and a nickel wiring arranged on the substrate, the method comprising: a nickel complex; and a solvent capable of dissolving the nickel complex. The method includes a step of applying a substance to a substrate to form a composition layer, and a step of irradiating the composition layer with light to precipitate nickel.

The materials used in the above method, the method for forming the composition layer, the light irradiation conditions, and other details and preferred embodiments are the same as those in the above-described method for manufacturing a conductor.

<Conductor forming composition>
The conductor-forming composition of the present disclosure includes a nickel complex and a solvent that can dissolve the nickel complex.

By using the above composition, a nickel conductor can be formed while suppressing nickel oxidation. Details and preferred embodiments of the above composition are the same as those of the composition used in the method for producing a conductor described above.

Hereinafter, the method for manufacturing the conductor described above will be described in more detail with reference to Examples, but the present disclosure is not limited to these Examples.

(1-1) Preparation of Composition 1 0.368 g (2 mmol) of nickel (II) formate dihydrate was added to 3.76 g of ethanol. Next, 0.24 g (6 mmol) of ethylenediamine (EDA) was added with stirring, and the mixture was further stirred for 30 minutes to obtain a purple nickel complex solution. The resulting solution was designated as Composition 1.

(1-2) Preparation of Composition 2 0.773 g (2.26 mmol) of sodium tetraphenylborate (TPB) was added as a counter anion precursor to the solution of the nickel complex obtained in (1-1) above. A white precipitate formed immediately upon addition of .0 g dissolved in water. This precipitate was collected by gravity filtration and then dried in a desiccator to obtain a salt of a nickel complex and tetraphenylborate ion. The obtained nickel complex, 0.04 g of a salt of tetraphenylborate ion, 0.5 g of 1-propanol and 0.5 g of 2-aminoethanol were mixed, and the mixture was stirred at room temperature (25°C) for 30 minutes to form a nickel complex. A solution (pale yellow) of a salt of tetraphenylborate ion was obtained. The resulting solution was designated as Composition 2.

(1-3) Preparation of Composition 3 0.827 g (445 mmol) of nickel (II) formate dihydrate was mixed with 2.40 g of 2-amino-1-methyl-1-propanol (AMP) and 4.50 g of methanol. It was added to the mixed solution and stirred for 24 hours to obtain a blue nickel complex solution. The resulting solution was designated as Composition 3.

(1-4) Formation of conductor on alumina substrate Using the prepared compositions 1 to 3, a composition layer was formed on an alumina substrate by spin coating (2000 rpm, 30 seconds). Next, the composition layer was irradiated with a CO ₂ laser in a pattern (focal length: 155 mm, output: 3.2 W, scan speed: 20 mm/sec, pattern width: 200 μm) to precipitate nickel. After light irradiation, portions of the composition layer where nickel was not precipitated were removed by etching with acetone. The above steps were performed in the atmosphere.

(1-5) X-ray diffraction measurement When performing X-ray diffraction (XRD) measurement of the area irradiated with light in (1-4) above, a peak derived from nickel was clearly observed, while a peak derived from nickel oxide was observed. No peak was observed. From this result, it was confirmed that the precipitate was high purity nickel.

(1-6) Electroless plating In (1-5) above, electroless plating (copper and nickel) was performed on the alumina substrate on which nickel was deposited in a pattern using Composition 2. As a result, it was confirmed that copper or nickel was deposited on the nickel as the plating time progressed, and the film thickness increased while the line width of the pattern was maintained constant.
The film thickness of the conductor 30 minutes after the start of electroless plating was measured using a laser microscope and found to be 1.83 μm (copper) and 5.81 μm (nickel).

(1-7) Electrolytic plating In (1-5) above, when electrolytic plating (copper and nickel) was performed on the alumina substrate on which nickel was deposited in a pattern using Composition 2, It was confirmed that copper or nickel was precipitated and the film thickness increased.
The film thickness of the conductor 10 minutes after the start of electrolytic plating was measured using a laser microscope and found to be 1.5 μm (copper) and 1.8 μm (nickel).
The electrolytic copper plating bath contains 10 g/L to 100 g/L of copper pyrophosphate, 80 g/L to 300 g/L of potassium pyrophosphate, and 0 ml/L to 10 ml/L of 28% ammonia water, and has a pH of 7. 5 to 10.0 was used. The bath temperature was 15° C. to 60° C., and the current density was 0.05 A/dm ² to 2.00 A/dm ² .
The electrolytic nickel plating bath contains 250 g/L to 450 g/L of nickel sulfate, 35 g/L to 55 g/L of boric acid, and 30 g/L to 60 g/L of nickel chloride, and has a pH of 3.5 to 5. 0 was used. The bath temperature was 40 to 75°C, and the current density was 0.05 A/dm ² to 2.00 A/dm ² .

(1-8) Formation of conductor on glass substrate A process was performed to develop adhesion between the surface of the glass substrate and the conductor. Specifically, a film of a colloidal silica dispersion having a particle size of about 100 nm diluted with ethanol (40% by mass) was formed on a glass substrate by a spin coating method, and dried at 100° C. for 10 minutes. Next, a film of a sol solution (10% by mass) of tetraethoxysilane (TEOS) was formed on the colloidal silica film by spin coating, and sintered at 500° C. for 30 minutes. A conductor was formed on the treated glass substrate in the same manner as on the alumina substrate. The formed body had excellent adhesion to the glass substrate.

From the above results, it was found that according to the method of the present disclosure, a nickel conductor can be formed while suppressing oxidation.

The disclosure of Japanese Patent Application No. 2018-099681 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference. Incorporated herein by reference.

Claims (23)

A step of applying a composition containing a nickel complex and a solvent capable of dissolving the nickel complex to a substrate to form a composition layer, and a step of irradiating the composition layer with light to precipitate nickel. A method for producing a conductor, wherein the nickel complex forms an organic solvent-soluble salt with a counter anion having 20 or more carbon atoms. The method for manufacturing a conductor according to claim 1, further comprising the step of applying metal plating on the deposited nickel. The method for manufacturing a conductor according to claim 1 or 2, wherein the light irradiation is performed using at least one selected from the group consisting of a CO ₂ laser, an Er laser, a xenon lamp, and an excimer lamp. The method for manufacturing a conductor according to any one of claims 1 to 3, wherein the light irradiation is performed in a pattern. The method for manufacturing a conductor according to any one of claims 1 to 4, which is carried out in the atmosphere. The method for producing a conductor according to any one of claims 1 to 5, wherein the nickel complex contains an amine compound as a ligand. The method for producing a conductor according to any one of claims 1 to 6, wherein the nickel complex contains an amino alcohol as a ligand. The method for producing a conductor according to any one of claims 1 to 7, wherein the counter anion is a tetraphenylborate ion. The method for manufacturing a conductor according to any one of claims 1 to 8, wherein the solvent is an organic solvent. A method for manufacturing a wiring board comprising a substrate and nickel wiring disposed on the substrate, the method comprising applying a composition containing a nickel complex and a solvent capable of dissolving the nickel complex to the substrate to form a composition layer. and a step of precipitating nickel by irradiating the composition layer with light, wherein the nickel complex contains a counter anion having 20 or more carbon atoms and a salt soluble in an organic solvent. A method of manufacturing a wiring board. The method for manufacturing a wiring board according to claim 10, further comprising the step of applying metal plating on the deposited nickel. The method for manufacturing a wiring board according to claim 10 or 11, wherein the light irradiation is performed using at least one selected from the group consisting of a CO ₂ laser, an Er laser, a xenon lamp, and an excimer lamp. The method for manufacturing a wiring board according to any one of claims 10 to 12, wherein the light irradiation is performed in a pattern. The method for manufacturing a wiring board according to any one of claims 10 to 13, which is performed in the atmosphere. The method for manufacturing a wiring board according to any one of claims 10 to 14, wherein the nickel complex contains an amine compound as a ligand. The method for manufacturing a wiring board according to any one of claims 10 to 15, wherein the nickel complex contains an amino alcohol as a ligand. The method for manufacturing a wiring board according to any one of claims 10 to 16 , wherein the counter anion is a tetraphenylborate ion . The method for manufacturing a wiring board according to any one of claims 10 to 17, wherein the solvent is an organic solvent. A conductor-forming composition comprising a nickel complex and a solvent capable of dissolving the nickel complex, wherein the nickel complex forms a salt soluble in an organic solvent with a counter anion having 20 or more carbon atoms. The composition for forming a conductor according to claim 19, wherein the nickel complex contains an amine compound as a ligand. The composition for forming a conductor according to claim 19 or 20, wherein the nickel complex contains an amino alcohol as a ligand. The conductor-forming composition according to any one of claims 19 to 21, wherein the counter anion is a tetraphenylborate ion. The conductor-forming composition according to any one of claims 19 to 22, wherein the solvent is an organic solvent.