JP2013196881A - Method for forming electrical conduction pattern, and composition for electrical conduction pattern formation by light irradiation or microwave heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition favorably used for effectively making electrically conductive a composition pattern printed on a substrate by selective heating using internal heating such as light irradiation and microwave heating, and a method for electrical conductivity.SOLUTION: A method for manufacturing an electrical conduction pattern, includes: applying, drying and depositing a flat composition including oxidized metal particles, a reductant agent, and a binder resin on a substrate; and irradiating the composition deposited on the substrate with light or heating it with a microwave to reduce the oxidized metal particles.

Description

  The present invention relates to a method for forming a conductive pattern and improvement of a composition for forming a conductive pattern by light irradiation or microwave heating.

  As a technique for producing a fine wiring pattern, a method of forming a wiring pattern by a lithography method using a combination of a copper foil and a photoresist is generally used, but this method has a long process number, drainage, The burden of waste liquid treatment is large, and environmental improvement is desired. Also known is a method of patterning a metal thin film produced by a heat deposition method or a sputtering method by a photolithography method. However, the heating vapor deposition method and the sputtering method are indispensable for a vacuum environment, and the price is very expensive. When applied to a wiring pattern, it is difficult to reduce the manufacturing cost.

  In view of this, there has been proposed a technique for producing a wiring by printing using a metal ink (including a metal oxide obtained by reducing an oxide with a reducing agent). Since the wiring technology by printing is capable of producing a large quantity of products at low cost and at high speed, the production of practical electronic devices has already been studied in part.

  However, in the method of heating and baking metal ink using a heating furnace, the heating process takes time, and if the plastic substrate cannot withstand the heating temperature required for baking the metal ink, the plastic substrate is used. There was a problem that the material had to be fired at a temperature that the material could withstand, and that it did not reach a satisfactory electrical conductivity.

  Therefore, as described in Patent Documents 1 to 3, there has been an attempt to convert the metal wiring by light irradiation using a composition (ink) containing nanoparticles.

  The method using light energy or microwave for heating may be able to heat only the ink part and is a very good method. However, when metal particles themselves are used, the conductivity of the resulting conductive film is satisfactory. When copper oxide is used, there is a problem that the porosity of the obtained conductive film is large, or copper oxide particles remain without being partially reduced.

  In addition, it is necessary to use metal or metal oxide particles having a diameter of 1 μm or less for the sintering, and there is a problem that the preparation of these nanoparticles is very expensive, and the energy during irradiation is also high. However, since the fine particles are fine particles, they have a drawback of being easily scattered before sintering.

Special table 2008-522369 International Publication 2010/110969 Pamphlet Special table 2010-528428 gazette

  In general, it can be said that a conductive film formed on a substrate has higher performance as the electrical conductivity is higher (volume resistivity is lower). Therefore, it is desirable to further improve the conductivity of the conductive pattern formed by the conventional technique.

  An object of the present invention is to provide a composition suitably used for efficiently conducting a composition pattern printed on a substrate by selective heating by internal heat generation such as light irradiation or microwave heating, and for conducting the composition. It is to provide a method.

  In order to achieve the above object, one embodiment of the present invention is a composition for forming a conductive pattern by light irradiation or microwave heating, and includes metal oxide particles having a flat shape, a reducing agent, and a binder resin. It is characterized by that.

  The metal oxide particles have a thickness of 10 to 800 nm. The aspect ratio of the metal oxide particles is 5 to 200.

  The metal oxide particles are copper oxide or cobalt oxide. Further, the metal oxide particles are any one of oxides having various oxidation states or a mixed particle thereof.

  Further, the reducing agent is a polyhydric alcohol or a carboxylic acid. Further, the binder resin is any one of polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol, and polyurethane.

  Moreover, it is characterized by including 20-200 mass parts of reducing agents and 1-50 mass parts of binder resin with respect to 100 mass parts of said metal oxide particles.

  One embodiment of the present invention is a method for forming a conductive pattern, wherein the conductive pattern forming composition is prepared, and the conductive pattern forming composition is irradiated with light or subjected to microwave heating.

  In addition, the light applied to the composition is continuous light having a wavelength of 200 to 3000 nm or pulsed light having a single light irradiation period (on) of 5 microseconds to 1 second.

  Further, the microwave for heating the composition has a wavelength of 1 m to 1 mm.

  According to the composition for forming a conductive pattern of the present invention, a pattern printed on a substrate can be efficiently made conductive by selective heating by internal heat generation such as light irradiation or microwave heating.

It is a figure for demonstrating the definition of pulsed light. 1 is a view showing an SEM photograph of flat copper oxide particles 1 produced for Example 1. FIG. It is a figure which shows the measurement result of TGA of the flat copper oxide particle 1 manufactured for Example 1. FIG. It is a figure which shows the measurement result of XRD of the flat copper oxide particle 1 manufactured for Example 1. FIG. 4 is a view showing an SEM photograph of flat copper oxide particles 2 produced for Example 2. FIG. It is a figure which shows the measurement result of XRD of the flat copper oxide particle 2 manufactured for Example 2. FIG. 4 is a view showing an SEM photograph of flat copper oxide particles 3 produced for Example 3. FIG. 6 is a view showing an SEM photograph of flat copper oxide particles 4 produced for Example 4. FIG. 2 is a diagram showing SEM photographs of the printed pattern manufactured in Example 1 before and after irradiation with pulsed light. FIG. It is a figure which shows the SEM photograph before and behind the pulsed light irradiation of the printing pattern manufactured in the comparative example 2. FIG.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described.

  In the conductive pattern forming method according to the present embodiment, a composition containing a metal oxide particle having a flat shape (hereinafter referred to as flat metal oxide particle) and a reducing agent is prepared, and the composition is irradiated with light or microscopically. A feature is that a metal sintered body is generated by wave heating to form a conductive pattern. Here, preparation refers to, for example, screen printing, gravure printing, or the like, or using a printing apparatus such as an ink jet printer, and forming a predetermined printing pattern with the above composition on an appropriate substrate, or on the entire surface of the substrate. It means forming the composition layer.

  The thickness of the flat metal oxide particles is preferably 10 to 800 nm, preferably 20 nm to 500 nm, more preferably 20 nm to 300 nm. If it is thinner than 10 nm, it is difficult to prepare, and if it is thicker than 800 nm, it becomes difficult to sinter. Further, the aspect ratio (particle width / thickness) must be large to some extent, and the effect of increasing the contact area cannot be obtained. On the other hand, if it is too large, the printing accuracy is lowered, and further, the particles cannot be dispersed well. Therefore, the preferred aspect ratio is in the range of 5 to 200, more preferably in the range of 5 to 100. The shape of the flat metal oxide particles is obtained by changing the observation location at a magnification of 30,000 times, observing the thickness and width by 10-point SEM observation, and obtaining the thickness as a number average value thereof.

  Examples of the flat metal oxide particles include copper oxide, cobalt oxide, nickel oxide, iron oxide, zinc oxide, indium oxide, and tin oxide. Among these, copper oxide is more preferable because the reduced metal has high conductivity. Further, cobalt oxide is more preferable in terms of other physical properties such as magnetism.

  Further, the flat metal oxide particles include oxides having various oxidation states, for example, those having different oxidation states such as cuprous oxide and cupric oxide.

  The composition for forming a conductive film according to the present invention must contain the flat metal oxide particles, but the metal oxide particles may have other shapes, for example, a spherical shape or a rod shape, or copper, cobalt, nickel, iron, or zinc. Indium, tin, or metal particles of these alloys can be used in combination. In that case, the flat metal oxide particles are preferably 70% by mass or more, more preferably 80% by mass or more based on the total particles.

  When a conductive film is formed by light irradiation or microwave heating using only spherical metal oxide particles without using flat metal oxide particles, especially when metal oxide particles with a small particle size are used. By chemical reduction sintering, a metal film in which particles are continuously connected can be provided. However, in order to reduce all the metal oxide particles to the center, it is necessary to increase the energy of the light or microwave to be irradiated and use metal oxide particles having a small particle diameter. For this reason, there is a problem that it is difficult to increase the thickness of the conductive film because part of the metal oxide particles blows off during light irradiation or microwave heating. In addition, when metal oxide particles having a large particle size are used so that they do not blow off during firing, there is a problem that the metal oxide inside the particles cannot be reduced and the resistance does not decrease.

  On the other hand, in the present embodiment, the metal sintered body is efficiently formed by performing light irradiation or microwave heating on a composition in which flat metal oxide particles having a flat shape and a reducing agent are mixed. It is characterized in that a conductive film is formed and the resistance is sufficiently lowered.

  Since the composition for forming a conductive pattern of the present embodiment is mainly composed of flat metal oxide particles, it contains a reducing agent for forming a conductive pattern by light irradiation or microwave heating. Reducing agents include alcohol compounds such as methanol, ethanol, isopropyl alcohol, butanol, cyclohexanol, and terpeniol, polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, and carboxylic acids such as formic acid, acetic acid, succinic acid, and succinic acid. , Carbonyl compounds like acetone, methyl ethyl ketone, cyclohexane, benzaldehyde, octyl aldehyde, ester compounds like ethyl acetate, butyl acetate, phenyl acetate, hydrocarbon compounds like hexane, octane, toluene, naphthalene, decalin I can do it. Of these, considering the efficiency of the reducing agent, polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin, and carboxylic acids such as formic acid, acetic acid and oxalic acid are preferred. The amount of the reducing agent blended is not limited as long as it is an amount necessary for the reduction of the flat metal oxide particles, but since it also serves as a solvent for a composition containing a binder resin, which will be described later, the flat metal oxide particles 20-200 mass parts is mix | blended with respect to 100 mass parts.

  In order to print the composition mainly composed of the flat metal oxide particles, a binder resin is required. Examples of the polymer compound that can be used as the binder resin include poly-N-vinyl compounds such as polyvinyl pyrrolidone and polyvinyl caprolactone, polyalkylene glycol compounds such as polyethylene glycol, polypropylene glycol, and polyTHF, polyurethanes, cellulose compounds and derivatives thereof, Thermoplastic resins and thermosetting resins such as epoxy compounds, polyester compounds, chlorinated polyolefins, and polyacryl compounds can be used. These binder resins have a difference in the degree of effect, but all have a function as a reducing agent. Among these, polyvinyl pyrrolidone is preferable when considering the binder effect, polyalkylene glycol such as polyethylene glycol and polypropylene glycol is preferable when considering the reducing effect, and a polyurethane compound is preferable from the viewpoint of adhesive strength as a binder. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol fall into the category of polyhydric alcohols, and have characteristics that are particularly suitable as reducing agents.

  As described above, the presence of a binder resin is indispensable for printing a composition for forming a conductive pattern mainly composed of flat metal oxide particles, but there is a problem that if it is used too much, it is difficult to develop conductivity. If the amount is too small, the ability to hold the particles together is lowered. Therefore, the usage-amount of 1-50 mass parts with respect to 100 mass parts of flat metal oxide particles, More preferably, 3-20 mass parts is preferable. Since the binder resin has a function as a reducing agent as described above, the reducing agent that does not serve as the binder resin is not an essential component in the conductive pattern forming composition of the present invention. However, when the amount of the binder resin alone is small, it is insufficient as a reducing agent. Therefore, it is preferable to use a reducing agent that also serves as a solvent for the binder resin in a range that satisfies the above-described mixing ratio.

  For the conductive pattern forming composition containing the flat metal oxide particles as a main component, a known organic solvent, water solvent, or the like is used as necessary for the purpose of adjusting the viscosity of the composition according to the printing method. be able to.

  The conductive pattern forming composition according to this embodiment may contain known ink additives (such as an antifoaming agent, a surface conditioner, and a thixotropic agent) as necessary.

  In order to make the composition for forming a conductive pattern conductive, the composition for forming a conductive pattern is subjected to light irradiation or microwave heating. Moreover, in order to form a conductive pattern on a substrate, the composition for forming a conductive pattern is printed on the substrate, and the light irradiation or microwave heating is performed. The material of the substrate is not particularly limited, and for example, a plastic substrate, a glass substrate, a ceramic substrate, or the like can be employed.

  As light irradiated to the composition for forming a conductive pattern, continuous light or pulsed light having a wavelength of 200 nm to 3000 nm is preferable, and pulsed light that is less likely to store heat during firing is more preferable. In this specification, “pulse light” means light having a short light irradiation period (irradiation time). When light irradiation is repeated a plurality of times, as shown in FIG. 1, the first light irradiation period (on ) And the second light irradiation period (on) means light irradiation having a period (irradiation interval (off)) in which light is not irradiated. Although FIG. 1 shows that the light intensity of the pulsed light is constant, the light intensity may change within one light irradiation period (on). The pulsed light is emitted from a light source including a flash lamp such as a xenon flash lamp. Using such a light source, the layer of the composition is irradiated with pulsed light. When irradiation is repeated n times, one cycle (on + off) in FIG. 1 is repeated n times. In addition, when irradiating repeatedly, when performing the next pulse light irradiation, it is preferable to cool from the base-material side so that a base material can be cooled to room temperature vicinity.

  The irradiation period (on) of the pulsed light is preferably in the range of 5 microseconds to 1 second, more preferably 20 microseconds to 10 milliseconds. If it is shorter than 5 microseconds, sintering does not proceed, and the effect of improving the performance of the conductive pattern is reduced. On the other hand, if the time is longer than 1 second, the adverse effects due to light deterioration and heat deterioration become larger. Irradiation with pulsed light is effective even if performed in a single shot, but can also be performed repeatedly as described above. In the case of repeated execution, the irradiation interval (off) is preferably in the range of 20 microseconds to 5 seconds, more preferably 2000 microseconds to 2 seconds. If it is shorter than 20 microseconds, it becomes close to continuous light and is irradiated without being allowed to cool after one irradiation, so that the substrate is heated and the temperature becomes considerably high. Also, if it is longer than 5 seconds, the cooling is progressed, so there is no reason for no effect at all, but the effect of repeated execution is reduced.

  Further, the conductive pattern forming composition can be heated by microwaves. The microwave used when heating the composition for forming a conductive pattern is an electromagnetic wave having a wavelength range of 1 m to 1 mm (frequency is 300 MHz to 300 GHz).

  Examples of the present invention will be specifically described below. In addition, the following examples are for facilitating understanding of the present invention, and the present invention is not limited to these examples.

  Moreover, in the following Examples and Comparative Examples, the volume resistivity is measured by Loresta GP manufactured by Mitsubishi Analytech Co., Ltd., and the shape of the flat particles is 10 points by FE-SEM S-5200 manufactured by Hitachi High-Tech Co., Ltd. Images were taken, and the thickness was obtained as a number average value of actually measured values. The spherical particles used in Comparative Example 1 were measured with a microtrack particle size distribution measuring apparatus MT3000II series USVR (laser diffraction / scattering method) manufactured by Nikkiso Co., Ltd., and the particle size was determined by spherical approximation and the median diameter was D50. D50 was similarly calculated | required also about the shape of the flat metal oxide particle used for the Example for reference.

<Preparation of flat copper oxide particles 1>
Polyvinylpyrrolidone (0.245 g), Cu (NO ₃ ) ₂ (0.374 g), and water (48 ml) were dissolved at room temperature, respectively, and NaOH (1.6 g) was added and mixed for 2 to 3 minutes. This solution was heated and reacted at 180 ° C. for 20 hours in an autoclave. The obtained precipitate was isolated by centrifugation and dried to obtain flat copper oxide particles 1 as flat metal oxide particles according to this example.

  2 (a) and 2 (b) show SEM photographs of the flat copper oxide particles 1 obtained by the above steps. As shown in FIGS. 2 (a) and 2 (b), the flat copper oxide particles 1 are plate-shaped (flat), the thickness of the particles is in the range of 80 to 120 nm, and the average value is 100 nm. The aspect ratio was 20. Further, D50 measured for reference was 1.28 μm.

Further, after drying the flat copper oxide particles 1, TGA (manufactured by Rigaku, Thermo
plus Evo II differential type differential thermobalance TG8120 (high temperature infrared heating TG-DTA)) (measuring condition: temperature rising from room temperature to 500 ° C. at a temperature rising rate of 5 ° C./min in a nitrogen atmosphere) 2 A thermal weight loss of .5% by mass was observed. Also, XRD (X-ray diffraction manufactured by Rigaku, curved IPX-ray diffractometer RINT RAPIDII, measurement condition: continuous scan measurement using a standard holder, X-ray tube: Cu (40 kV / 30 mA), collimator: f0.8 mm, (ω: 20 °, f: 1 / sec, scan time: 360 sec, receiving slit (RS): 0.15 mm) were also measured. The measurement result of TGA is shown in FIG. 3, and the measurement result of XRD is shown in FIG. From TGA, it can be seen that the polymer remains, and from XRD, what was almost cupric oxide at the time of synthesis is partially changed to cuprous oxide (cuprous oxide) at the time of TGA measurement. I understand.

<Preparation of flat copper oxide particles 2>
Polyvinylpyrrolidone (0.245 g), Cu (NO ₃ ) ₂ (0.374 g), and water (48 ml) were dissolved at room temperature, respectively, and NaOH (1.6 g) was added and mixed for 2 to 3 minutes. This solution was heated and reacted at 120 ° C. for 20 hours in an autoclave. The obtained precipitate was isolated by centrifugation and dried to obtain flat copper oxide particles 2 as flat metal oxide particles according to this example.

  5A and 5B show SEM photographs of the flat copper oxide particles 2 obtained by the above process. As shown in FIGS. 5A and 5B, the flat copper oxide particles 2 were plate-like (flat), the particle thickness was 50 nm, and the aspect ratio was 40. Moreover, D50 measured for reference was 0.808 μm.

  Further, after the flat copper oxide particles 2 were dried, XRD (X-ray diffraction) was also measured under the same measurement conditions as the flat copper oxide particles 1. The measurement result of XRD is shown in FIG. From the results of XRD, it can be seen that, unlike the flat copper oxide particles 1, since the flakes became thinner, they are easily reduced and become almost copper.

<Preparation of flat copper oxide particles 3>
Polyvinylpyrrolidone (0.245 g), Cu (NO ₃ ) ₂ (0.374 g), and water (48 ml) were dissolved at room temperature, respectively, and NaOH (1.6 g) was added and mixed for 2 to 3 minutes. This solution was heated and reacted at 80 ° C. for 20 hours in an autoclave. The obtained precipitate was isolated by centrifugation and dried to obtain flat copper oxide particles 3 as flat metal oxide particles according to this example.

  FIGS. 7A and 7B show SEM photographs of the flat copper oxide particles 3 obtained by the above steps. As shown in FIGS. 7A and 7B, the flat copper oxide particles 3 were plate-shaped (flat), the particle thickness was 30 nm, and the aspect ratio was 68. The D50 measured for reference was 3.69 μm.

<Preparation of flat copper oxide particles 4>
Polyvinylpyrrolidone (0.245 g), Cu (NO ₃ ) ₂ (0.374 g), and water (48 ml) were dissolved at room temperature, respectively, and NaOH (1.6 g) was added and mixed for 2 to 3 minutes. This solution was heated and reacted at 80 ° C. for 2 hours in a glass container. The obtained precipitate was isolated by centrifugation and dried to obtain flat copper oxide particles 4 as flat metal oxide particles according to this example.

  8 (a) and 8 (b) show SEM photographs of the flat copper oxide particles 4 obtained by the above process. As shown in FIGS. 8A and 8B, the flat copper oxide particles 4 were plate-shaped (flat), the particle thickness was 35 nm, and the aspect ratio was 30. Moreover, D50 measured for reference was 1.62 μm.

Example 1
A mixed aqueous solution (mass ratio ethylene glycol: glycerin: water = 70: 15: 15) of ethylene glycol and glycerin (reagent manufactured by Kanto Chemical Co., Ltd.) was prepared as a reducing agent, and polyvinylpyrrolidone ( Nippon Catalyst Co., Ltd.) was dissolved to prepare a 40% by mass binder resin solution. 1.5 g of this binder resin solution and 0.5 g of the above mixed aqueous solution are mixed, 6.0 g of the prepared flat copper oxide particles 1 are added, and a rotating / revolving vacuum mixer Awatori Netaro ARV-310 (Sinky Corporation) Were mixed well to produce a paste for printing.

The obtained paste was screen printed to print a 2 cm × 2 cm square pattern on a polyimide film (thickness 25 μm) (Kapton 100N, manufactured by Toray DuPont Co., Ltd.), and the solvent was removed by drying in a room temperature air atmosphere. . The sample print pattern thus obtained was irradiated with pulsed light using PulseForge 3300 manufactured by Novacentrix to convert the pattern into a conductive pattern. The irradiation conditions were a single irradiation with a voltage of 250 V and a pulse width of 1600 microseconds. The pulse energy at that time was 3.47 J / cm ² . The thickness of the conductive pattern formed as described above was 25 μm, and the volume resistivity was 2.05 × 10 ⁻⁵ Ω · cm. Table 1 shows the measurement results. In addition, the printed pattern after drying removal before light irradiation was insulative, and volume resistivity could not be measured with Mitsubishi Analitech's Loresta GP.

  FIGS. 9A and 9B show SEM photographs of the pattern before and after pulse light irradiation. It can be seen that there are fewer vacancies in FIG. 9B after the pulse light irradiation than in FIG. 9A before the pulse light irradiation.

Examples 2-4
In the same manner as in Example 1, the other flat copper oxide particles 2 to 4 were used to make ink (paste preparation), and light irradiation after printing was performed. The results are shown in Table 1.

Comparative Example 1
As spherical copper oxide particles, 6 g of 1-550 (D50 = 720 nm) manufactured by Furukawa Chemicals Co., Ltd. was used, and a paste for printing was produced in the same manner as in Example 1. The obtained paste was pattern-printed in the same manner as in Example 1 and irradiated with light. The thickness of the formed conductive pattern was 23 μm, but the volume resistivity was high and could not be measured with a Loresta GP manufactured by Mitsubishi Analitech Co. The measurement results are shown in Table 1.

Comparative Example 2
As a spherical metal oxide particle, 6.0 g of NanoTek CuO (D50 = 270 nm) manufactured by C-I Kasei Co., Ltd. was used, and a paste for printing was produced in the same manner as in Example 1. The obtained paste was pattern-printed in the same manner as in Example 1 and irradiated with light. The formed conductive pattern had a thickness of 22 μm and a volume resistivity of 7.68 × 10 ⁻⁴ Ω · cm. The measurement results are shown in Table 1.

  10A and 10B show SEM photographs of the pattern before and after the pulsed light irradiation of Comparative Example 2. FIG. It can be seen that there are very many holes in FIG. 10B after the pulse light irradiation, compared to FIG. 10A before the pulse light irradiation. Since spherical particles having a small particle diameter are used, it is considered that air is easily blown out when intense light irradiation is performed in a short time, and voids are easily generated inside the converted conductor.

  As shown in Table 1, it can be seen that the volume resistivity of the conductive patterns according to Examples 1 to 4 is one digit lower than that of the conductive patterns according to Comparative Examples 1 and 2.

Claims (11)

  A composition for forming a conductive pattern by light irradiation or microwave heating, comprising a metal oxide particle having a flat shape, a reducing agent, and a binder resin.   The conductive pattern forming composition according to claim 1, wherein the metal oxide particles have a thickness of 10 to 800 nm.   The conductive pattern forming composition according to claim 1 or 2, wherein the metal oxide particles have an aspect ratio of 5 to 200.   The said metal oxide particle is a copper oxide or a cobalt oxide, The composition for conductive pattern formation as described in any one of Claims 1-3 characterized by the above-mentioned.   The conductive pattern forming composition according to any one of claims 1 to 4, wherein the metal oxide particles are any of oxides having various oxidation states or a mixed particle thereof. .   The conductive pattern forming composition according to claim 1, wherein the reducing agent is a polyhydric alcohol or a carboxylic acid.   The composition for forming a conductive pattern according to any one of claims 1 to 6, wherein the binder resin is any one of polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol, and polyurethane.   The composition for conductive pattern formation as described in any one of Claims 1-7 containing 20-200 mass parts of reducing agents and 1-50 mass parts of binder resin with respect to 100 mass parts of said metal oxide particles. A conductive pattern forming composition according to any one of claims 1 to 8 is prepared,
Performing light irradiation or microwave heating on the composition for forming a conductive pattern;
A method of forming a conductive pattern.   10. The conductive pattern according to claim 9, wherein the light applied to the composition is continuous light having a wavelength of 200 to 3000 nm or pulsed light having a single light irradiation period of 5 microseconds to 1 second. Forming method.   The method for forming a conductive pattern according to claim 9, wherein the microwave for heating the composition has a wavelength of 1 to 1 mm.

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