JP2009048959A - Method for forming conductive film and electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a method for forming a conductive film enabling enlargement of a selected region on a substrate; a method for forming the conductive film in which the deterioration of productivity can be suppressed when the drawing area is made greater; and an electrode formed by these methods. <P>SOLUTION: The conductive film is obtained by coating ink containing ultrafine metal particles on the substrate and then by sintering the ink at a temperature of ≤200°C while radiating charged particle beam thereto. The charged particle beam is to be an electronic beam. In addition, the conductive film is obtained by coating the ink containing the ultrafine metal particle on the substrate and then sintering at a temperature of ≤200°C while radiating ultra violet rays thereto using an ultra violet ray lamp. In either case, coating is preferably carried out by an ink-jet method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for forming a conductive film and an electrode formed by this method.

  In recent years, with the increase in the degree of integration of semiconductor devices, the dimensions of individual elements have been reduced, and the widths of wirings and gates constituting each element have also been reduced. For this reason, a technique for making the conductive film into a fine pattern is important.

  Examples of a method for forming a conductive film over a substrate include a vacuum evaporation method and a sputtering method. The film obtained by these methods is processed into a desired pattern by photolithography. However, the photolithography method has a problem that the process is complicated and the waste of the material to be used is large.

  On the other hand, a conductive film pattern is also formed by an ink jet method. According to this method, a fine pattern can be directly formed on the substrate. Therefore, as compared with the above-described method, not only the process can be shortened, but also waste of materials to be used can be reduced.

  In the ink jet method, ink containing metal fine particles is ejected to a predetermined portion on a substrate. By firing the discharged material, a desired conductive film pattern can be formed on the substrate. Here, in order to reduce the specific resistance of the obtained conductive film, it is usually necessary to fire at a temperature exceeding 200 ° C. This is because the specific resistance increases rapidly at a temperature of 200 ° C. or lower. Therefore, there is a problem that a substrate that can withstand a temperature higher than 200 ° C. must be used, and the selection range of the substrate becomes narrow.

  Patent Document 1 describes that a laser is used as a baking means for ink discharged onto a substrate by an ink jet method. According to this method, since the laser light is focused on the ink portion, only this portion can be baked with high energy. Therefore, it can be applied to a substrate having low heat resistance such as a plastic substrate.

JP 2004-55363 A

  As described above, in the method of Patent Document 1, the focus of the laser light is focused on the ink portion for irradiation. For this reason, when the drawing area of a conductive film pattern becomes large, processing takes time and there exists a possibility that productivity may fall. In particular, in recent years, flat panel displays such as liquid crystal displays, plasma displays, organic EL displays, and field emission displays have been increased in screen size, and the conductive film pattern drawing area tends to increase. Therefore, a decrease in productivity due to the above reasons is a problem.

  The present invention has been made in view of these points. That is, an object of the present invention is to provide a method for forming a conductive film capable of widening the selection range of a substrate and an electrode made of a conductive film formed by this method.

  Another object of the present invention is to provide a method for forming a conductive film that can suppress a decrease in productivity when the drawing area increases, and an electrode made of the conductive film formed by this method.

  Other objects and advantages of the present invention will become apparent from the following description.

The first aspect of the present invention is a step of applying an ink containing ultrafine metal particles on a substrate;
And a step of baking the ink at a temperature of 200 ° C. or lower while irradiating a charged particle beam to obtain a conductive film.

  In the first aspect of the present invention, the charged particle beam may be an electron beam.

The second aspect of the present invention is a step of applying an ink containing ultrafine metal particles on a substrate;
And a step of baking the ink at a temperature of 200 ° C. or lower while irradiating ultraviolet rays with an ultraviolet lamp to obtain a conductive film.

  In the first and second aspects of the present invention, the coating is preferably performed by an ink jet method.

  In the first aspect and the second aspect of the present invention, the substrate may be a resin substrate.

  In the first and second aspects of the present invention, the metal ultrafine particles preferably have an average particle diameter of 100 nm or less.

  In the first and second aspects of the present invention, the metal ultrafine particles are made of gold, silver, copper, palladium, tin, platinum, tungsten, nickel, tantalum, indium, zinc, titanium, chromium, iron, and cobalt. At least one metal selected from the group consisting of these, or an ultrafine particle of an alloy or oxide of these metals can be used.

  A third aspect of the present invention relates to an electrode comprising the conductive film formed according to the first aspect or the second aspect of the present invention.

  According to the first aspect of the present invention, since the ink is baked at a temperature of 200 ° C. or lower while irradiating the charged particle beam, the invention can be applied to a substrate having a heat resistant temperature of 200 ° C. or lower.

  According to the second aspect of the present invention, since the ink is baked at a temperature of 200 ° C. or lower while irradiating the ultraviolet ray with an ultraviolet lamp, the ink can be applied to a substrate having a heat resistant temperature of 200 ° C. or lower. It is also possible to suppress a decrease in productivity when the drawing area increases.

  According to the 3rd aspect of this invention, it can be set as the electrode which has favorable specific resistance.

  Below, the formation method of the electrically conductive film by this invention is demonstrated in detail.

  First, an ink containing ultrafine metal particles is prepared as a raw material for the conductive film.

  As the ultrafine metal particles, ultrafine metal particles having high conductivity are used. Specifically, at least one metal selected from the group consisting of gold, silver, copper, palladium, tin, platinum, tungsten, nickel, tantalum, indium, zinc, titanium, chromium, iron and cobalt, or these It can be an ultrafine particle of metal alloy or oxide. Of these, silver or copper is preferably used because of its high conductivity. The average particle diameter of the ultrafine metal particles is preferably 100 nm or less, and more preferably 10 nm or less.

  As a method for obtaining ultrafine metal particles, for example, an in-gas evaporation method in which a metal is evaporated in a reduced-pressure inert gas atmosphere and then recovered as ultrafine particles on a cooling unit can be cited. By mixing the ultrafine metal particles obtained by this method with an organic solvent, an ink can be obtained. In order to prevent the ultrafine particles from aggregating, for example, when the metal is evaporated, the vapor of the organic solvent is placed in the vacuum chamber. The surface of the ultrafine metal particles is preferably covered with an organic solvent. Thereby, aggregation of the metal ultrafine particles in the organic solvent can be prevented, and an ink in a state where the ultrafine particles are well dispersed can be obtained.

  The ink can also be obtained by the following method. According to this method, an ink suitable for inkjet can be obtained. That is, the ink-jet nozzle is not clogged, and the selection range of the solvent to be used is wide, so that the ink having characteristics (such as viscosity and surface tension) suitable for the ink-jet method can be obtained.

  First, after evaporating a metal in a gas atmosphere in which the vapor of the first solvent exists and bringing the vapor of the metal into contact with the vapor of the first solvent, the first vapor is collected on the cooling unit, A metal ultrafine particle dispersion in which metal fine particles are dispersed in a solvent is obtained (first step). Next, a second solvent, which is a low molecular weight polar solvent, is added to the dispersion to precipitate the ultrafine metal particles, and then the supernatant is discarded to remove the first solvent (second step). When a third solvent is added to the remaining sediment, an ink in which ultrafine metal particles having a particle diameter of 100 nm or less are dispersed in an independent state is obtained (third step).

  In the first step, first, the metal is evaporated in an atmosphere of a vacuum chamber and an inert gas such as He having a pressure of 10 Torr or less. The evaporated metal vapor is then cooled and collected. At this time, the vapor of the first solvent is introduced into the vacuum chamber, and the vapor of the first solvent is brought into contact with the surface of the metal at the stage of grain growth. Thereby, a dispersion liquid in which the ultrafine metal particles are dispersed independently and uniformly in the first solvent is obtained.

  In the second step, first, a second solvent is added to the dispersion obtained in the first step. Then, since the ultrafine metal particles contained in the dispersion liquid settle, the supernatant liquid is removed by a stationary method or a decantation method. By repeating this operation a plurality of times, the first solvent can be substantially removed. Thereby, when the metal vapor evaporated in the first step is condensed, a by-product generated by the modification of the coexisting first solvent can be removed. Depending on the application, it is necessary to use ink dispersed in a low-boiling solvent, water, or an alcohol solvent that is difficult to use in the first step. If the first solvent is removed in the second step and then solvent replacement is performed in the next third step, ink dispersed in such a solvent can be obtained.

  In the third step, a new third solvent is added to the sediment obtained in the second step to perform solvent replacement. Thereby, a dispersion liquid in which ultrafine metal particles having an average particle diameter of 100 nm or less are dispersed in an independent state, that is, the ink in the present embodiment can be obtained.

  In the above example, it is preferable to add a dispersant in the first step and / or the third step. In addition, when adding a dispersing agent at a 3rd process, you may be a dispersing agent which does not melt | dissolve in the solvent (1st solvent) used at a 1st process. Examples of the dispersant include at least one selected from the group consisting of alkylamines, carboxylic acid amides, and aminocarboxylates. As the alkylamine, those having a main skeleton having 4 to 20 carbon atoms are preferable, and those having a main skeleton having 8 to 18 carbon atoms are preferable from the viewpoint of stability and ease of handling. If the alkylamine has 3 or less carbon atoms, the basicity of the amine is too strong and the ultrafine metal particles may be corroded. On the other hand, if the number of carbon atoms exceeds 20, the viscosity of the ink increases, and the ease of handling may decrease. The alkylamine may be any of primary to tertiary, but primary alkylamine is preferably used from the viewpoint of stability and ease of handling.

  Content of the alkylamine as a dispersing agent can be 0.1-10 mass% with respect to a metal ultrafine particle, and it is preferable to set it as 0.2-7 mass%. If it is less than 0.1% by mass, the metal ultrafine particles may aggregate without being dispersed in an independent state. On the other hand, if it exceeds 10% by mass, the viscosity of the ink may be increased to form a gel substance.

  Specific examples of alkylamines include butylamine, octylamine, dodecylamine, hexadodecylamine, octadecylamine, cocoamine, tallowamine, hydrogenated tallowamine, primary amines such as oleylamine, laurylamine and stearylamine, dicocoamine, dihydrogenated tallowamine and Secondary amines such as distearylamine, tertiary amines such as dodecyldimethylamine, didodecylmonomethylamine, tetradecyldimethylamine, octadecyldimethylamine, cocodimethylamine, dodecyltetradecyldimethylamine and trioctylamine, naphthalenediamine, stearyl Examples include diamines such as propylene diamine, octamethylene diamine, and nonane diamine. Specific examples of carboxylic acid amides and aminocarboxylic acid salts include stearic acid amide, palmitic acid amide, lauric acid lauryl amide, oleic acid amide, oleic acid diethanolamide, oleic acid lauryl amide, stearanilide or oleylaminoethylglycine. Is mentioned.

  In the above example, the first solvent is a solvent for producing ultrafine metal particles used in the gas evaporation method, and has a relatively boiling point so that the ultrafine metal particles can be easily liquefied when cooled and collected. High solvent. As the first solvent, a solvent containing at least one selected from the group consisting of alcohols having 5 or more carbon atoms, for example, terpineol, citronol, geraniol, and phenethyl alcohol, or organic esters, for example, benzyl acetate And a solvent containing at least one selected from the group consisting of ethyl stearate, methyl oleate, ethyl phenylacetate and glyceride. In addition, it is preferable to select suitably according to the kind of ultrafine metal particle to be used.

  The second solvent may be any one that can precipitate the ultrafine metal particles in the dispersion and separate and remove the first solvent. Specifically, a low molecular weight polar solvent such as acetone can be used.

  Examples of the third solvent include liquids at room temperature such as nonpolar hydrocarbons having 6 to 20 carbon atoms in the main chain, water, or alcohols having 15 or less carbon atoms. In the case of nonpolar hydrocarbons, if the number of carbon atoms is less than 6, drying becomes too fast, and handling of the resulting ink becomes difficult. On the other hand, when the carbon number exceeds 20, problems such as increase in the viscosity of the ink or remaining of carbon after firing occur. In the case of alcohol, the same problem occurs when the number of carbon atoms exceeds 15. For example, long-chain alkanes such as hexane, heptane, octane, decane, undecane, dodecane, tridecane and trimethylpentane, cyclic alkanes such as cyclohexane, cycloheptane and cyclooctane, and fragrances such as benzene, toluene, xylene, trimethylbenzene and dodecylbenzene Alcohols such as group hydrocarbons, hexanol, heptanol, octanol, decanol, cyclohexanol and terpineol can be used. These solvents may be used alone or in combination. For example, it can be a mineral spirit that is a mixture of long-chain alkanes.

  When the ink is applied by an inkjet method, the viscosity is preferably 1 to 100 mPa · s, more preferably 1 to 10 mPa · s at a temperature of 0 to 50 ° C. The surface tension of the ink can be 25 to 80 mN / m, and preferably 30 to 60 mM / m. Such an ink should be suitable for maintaining ink supply stability and droplet formation flight stability at the time of application, and realizing high-speed responsiveness of the head of an inkjet device. Can do.

  Further, when the ink jet method is used, the concentration of ultrafine metal particles in the ink is preferably 10 to 70% by mass, and more preferably 10 to 50% by mass. If it is less than 10% by mass, values such as viscosity and surface tension are sufficiently satisfied, but the electric resistance of the conductive film obtained after firing is not sufficient for a conductive circuit. On the other hand, when it exceeds 70% by mass, values such as viscosity and surface tension are out of the above ranges, and it becomes impossible to obtain ink suitable for the ink jet method.

  The ultrafine metal particles can also be obtained by a chemical reduction method such as a liquid phase reduction method instead of the gas evaporation method. In this case, as a raw material for producing metal ultrafine particles, for example, metal-containing organic compounds such as bishexafluoroacetylacetonate copper, bisacetylacetonate nickel, and bisacetylacetonate cobalt can be used. Specifically, first, the above raw materials are dissolved in a suitable solvent and a dispersing agent is added, and then thermally decomposed at a predetermined temperature to generate ultrafine metal particles. Thereafter, when the solvent is replaced with the third solvent or the like in the above example, an ink in which ultrafine metal particles having an average particle diameter of about 100 nm or less are dispersed is obtained. In this case, the obtained ink can maintain a stable dispersion state even if it is concentrated to a concentration of 80% by mass by heating in vacuum.

  In the present embodiment, a metal-containing organic compound such as an organosilicon compound and an organomanganese compound can be added to the ink containing ultrafine metal particles in order to improve the adhesion to the substrate. As the organosilicon compound, those which are soluble in a nonpolar hydrocarbon solvent that is liquid at room temperature and have a decomposition temperature of about 150 to 250 ° C. are used. For example, diphenylsilane, tetraallylsilane, or decamethyltetrasiloxane can be used. Moreover, as an organic manganese compound, for example, manganese octoate, manganese naphthenate, manganese linoleate, or the like can be used. The addition amount is preferably about 0.5 to 10% by mass of silicon or manganese with respect to the mass of the ultrafine metal particles. An addition amount of less than 0.5% by mass does not contribute to the improvement of adhesion. On the other hand, when the addition amount exceeds 10% by mass, the specific resistance of the conductive film increases.

Examples of other metal-containing organic compounds having an effect on adhesion include at least one selected from the group consisting of silicon, manganese, chromium, nickel, titanium, magnesium, aluminum, germanium, tantalum, niobium and vanadium. Examples thereof include fatty acid salts containing metals. Among these, those having a decomposition temperature of 300 ° C. or less are preferable. _{Specifically,} and the like _{(C 17 H 35 COO) 2} Mg , or _{(C 17 H 35 COO) 3} Al.

  When an ink containing ultrafine metal particles is prepared, it is applied onto a substrate. An insulating film or the like may be formed on the substrate, and ink may be applied on the insulating film.

  Various substrates can be used depending on the application. In particular, in the present invention, since the temperature during ink firing is 200 ° C. or lower (as will be described later), a resin substrate can also be used. For example, for flat panel display applications, a transparent substrate made of a material having a high transmittance for visible light, specifically, an inorganic glass substrate such as alkali glass, alkali-free glass and quartz glass, or polyester, polycarbonate, Examples of the resin substrate include fluorine-containing polymers such as polyether, polysulfone, polyethersulfone, polyvinyl alcohol, and polyvinyl fluoride. Furthermore, depending on the application, acrylic resins such as polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, polyarylate, phenoxy resins, polyolefin resins, nylon, styrene resins, and A resin substrate made of ABS resin or the like can also be used.

  Examples of the ink application method include various methods such as a spin coating method, a spray method, a dipping method, a roll coating method, a screen printing method, a contact printing method, a slit coating method, and an ink jet method. In particular, the ink jet method is preferably used. In the ink jet method, a necessary amount of ink can be applied only to a necessary region of the substrate, so that a desired pattern can be directly formed on the substrate. Therefore, the number of steps can be reduced compared with a method in which an unnecessary portion of the conductive film is removed by photolithography after applying ink on the entire surface of the substrate and baking to form a conductive film. Waste can also be reduced. Furthermore, the problem of waste liquid generated in the etching process can be solved.

  As described above, the ink-jet method is a method in which ink droplets are directly ejected onto a substrate, and a desired pattern can be formed without producing a printing block such as offset printing. Inkjet apparatus methods are broadly classified into a continuous type (continuous discharge type) and an on-demand type, but any method may be used in the present embodiment.

  In the continuous type, ink is continuously ejected from a nozzle by a pump, and then becomes a fine droplet by an ultrasonic oscillator. Electric charges are applied to the generated ink droplets via the deflection electrode. As a result, the ink droplet is bent in the trajectory and reaches the substrate surface. On the other hand, ink droplets whose trajectory is not bent by the deflection electrode are sucked into a collection port called a gutter and then returned to the ink tank for reuse.

  In the continuous type, the ink is always ejected continuously even when the ink is not ejected onto the substrate. In contrast, the on-demand type is a method in which a necessary amount of ink is ejected when necessary. This method has an advantage that the apparatus can be downsized as compared with the continuous type. The on-demand type is divided into a piezo method and a thermal method depending on the method of applying pressure to the ink droplets. The piezo method is a method in which a piezo element (piezoelectric element) that deforms when a voltage is applied is attached to a fine tube filled with ink, and the ink is ejected out of the tube by applying a voltage to the deformed micro tube. The thermal method is a method in which bubbles are generated in the ink in the tube by heating to eject the ink.

  After the ink is applied on the substrate, the ink is dried by heating to remove the solvent contained in the ink. Next, the ink is baked to form a conductive film pattern. Specifically, the ink is baked at a temperature of 200 ° C. or lower while being irradiated with a charged particle beam or ultraviolet rays.

  When an energy beam such as a charged particle beam or ultraviolet light is irradiated onto ink containing ultrafine metal particles, the energy beam is efficiently absorbed by the ink and converted into fusion between the ultrafine particles or grain growth. Therefore, if the energy beam is irradiated together with the heating, the heating temperature can be lowered and the heating time can be shortened as compared with the case where only the heating is performed. In this invention, heating temperature shall be 200 degrees C or less. By irradiating the energy beam simultaneously with the heating, a conductive film having a specific resistance equivalent to that when firing at a temperature exceeding 200 ° C. is obtained. Further, it can be applied to a substrate having a heat resistant temperature of 200 ° C. or lower. Further, even when other members such as an insulating film are provided on the substrate, it is possible to perform the baking while minimizing damage given to these members by heat.

  Hereinafter, an example in which an energy beam is irradiated during heating and a case where only heating is performed will be described.

  First, an ink dispersed in toluene in a state in which octanoic acid having 8 carbon atoms and 2-ethylhexylamine having 8 carbon atoms were adhered around the ultrafine Ag particles obtained by the gas evaporation method was prepared. The concentration of Ag ultrafine particles in the ink was 40% by mass.

  Next, a glass substrate was set on a spin coater, and while rotating at a rotational speed of 2000 rpm, ink was dropped from above the glass substrate to apply the ink onto the glass substrate. Next, the ink was dried by heating to remove the solvent contained in the ink. The application conditions of the spin coater were set so that the film thickness of the ink obtained after drying was 0.2 μm.

  Next, the ink was baked under any of conditions A to D.

  In A, in an inert gas atmosphere, an electron beam was irradiated for 20 minutes at an acceleration voltage of 35 kV with a substrate temperature set at 120 ° C. under a pressure of 5 Pa. The specific resistance of the obtained conductive film was 3.5 μΩcm, and the specular reflectance at a wavelength of 550 nm was 90%.

In B, with the substrate temperature set at 120 ° C., ultraviolet rays with a wavelength of 172 nm were irradiated at 40 mW / cm ² for 20 minutes using an excimer lamp filled with Xe gas. The specific resistance of the obtained conductive film was 5 μΩcm, and the specular reflectance at a wavelength of 550 nm was 90%.

  In C, the substrate temperature was set to 120 ° C. and heated under a pressure of 5 Pa in an inert gas atmosphere. The specific resistance of the obtained conductive film was 420 μΩcm, and the specular reflectance at a wavelength of 550 nm was 89%.

  In D, heating was performed in a firing furnace set at 220 ° C. in the air. The specific resistance of the obtained conductive film was 3 μΩcm, and the specular reflectance at a wavelength of 550 nm was 91%.

  The results of A to D are summarized in Table 1. As can be seen from this table, even when the heating temperature is 120 ° C., the specific resistance and reflectance equivalent to those when heated at a temperature of 220 ° C. can be obtained by irradiation with an electron beam or ultraviolet rays. On the other hand, the specific resistance is remarkably higher than the others by simply heating at a temperature of 120 ° C.

  In this embodiment mode, the charged particle beam can be an electron beam, an ion beam, a plasma beam, or the like, and among these, an electron beam is preferably used.

  Curing of the ink by the electron beam is generally discussed by the depth of curing. This cure depth is calculated very accurately from the voltage and ink characteristics and is controlled by the voltage and current that can be set by the power supply. Therefore, if an electron beam is used for ink firing, it is easy to design an apparatus suitable for firing. In addition, with an electron beam, the peak of energy absorbed per unit volume (absorbed dose) is between the front and back surfaces of the object, so the surface absorbed dose and the back absorbed dose can be easily set to the same level. Can do. Therefore, the entire ink can be uniformly cured, or a conductive film having good adhesion to the substrate can be obtained. Further, in the case of curing with an electron beam, since the temperature rise of the object is small, it is effective to suppress the temperature rise of the substrate, and it is more easily applied to the substrate having a low heat resistant temperature.

In the present embodiment, when ultraviolet rays are used for curing the ink, an ultraviolet lamp is used instead of a laser. Thereby, compared with the case where a laser is used, the fall of productivity accompanying the increase in the drawing area of an electrically conductive film pattern can be suppressed. This is because, since the irradiation area of the ultraviolet lamp is large, an increase in processing time due to an increase in the drawing area can be suppressed. In addition, it is preferable that the irradiation amount of an ultraviolet-ray shall be about 5-200 mW / cm < ² >.

  Examples of the ultraviolet lamp include a xenon lamp, an ultra high pressure UV lamp, a high pressure UV lamp, a low pressure UV lamp, a deep UV lamp, and an excimer lamp. For example, in the case of an excimer lamp, a type in which Ar gas having a maximum intensity at a wavelength of 126 nm is enclosed, a type in which Kr gas having a maximum intensity at a wavelength of 146 nm is enclosed, and a type in which Xe gas having a maximum intensity at a wavelength of 172 nm is enclosed. A type in which KrCl gas having a maximum intensity at a wavelength of 222 nm is sealed, a type in which XeCl gas having a maximum intensity at a wavelength of 308 nm is sealed, or the like can be used.

  By baking the ink as described above, a conductive film pattern is formed on the substrate. This conductive film pattern has a specific resistance equivalent to that when fired at a temperature exceeding 200 ° C., and is preferably used, for example, as an electrode of a flat panel display.

  According to the present embodiment, since the ink is baked at a temperature of 200 ° C. or less while irradiating the energy beam, the conductive material having a good specific resistance even on the resin substrate having a lower heat resistant temperature than the substrate made of the inorganic material. A film pattern can be formed. Therefore, it is possible to expand the selection range of the substrate as compared with the case of curing only by heating. Further, even when other members such as an insulating film are provided on the substrate, it is possible to perform baking while minimizing the damage given to these members by heat.

  In this embodiment mode, an electron beam can be used when firing ink. Since the degree of curing of the electron beam can be controlled by voltage and ink characteristics, it is possible to easily design an apparatus suitable for curing of ink. In addition, curing with an electron beam is easy to achieve uniform curing of the ink, and it is easy to obtain good adhesion to the substrate.

  In the present embodiment, when the ink is baked, ultraviolet rays can be irradiated using an ultraviolet lamp. According to this method, it is possible to suppress a decrease in productivity when the drawing area becomes larger than in the case of irradiation with a laser.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Claims (8)

Applying an ink containing ultrafine metal particles on a substrate;
And a step of firing the ink at a temperature of 200 ° C. or lower while irradiating a charged particle beam to obtain a conductive film.   The method for forming a conductive film according to claim 1, wherein the charged particle beam is an electron beam. Applying an ink containing ultrafine metal particles on a substrate;
And a step of baking the ink at a temperature of 200 ° C. or lower while irradiating ultraviolet rays with an ultraviolet lamp to obtain a conductive film.   The method for forming a conductive film according to claim 1, wherein the coating is performed by an inkjet method.   The method for forming a conductive film according to claim 1, wherein the substrate is a resin substrate.   The method for forming a conductive film according to claim 1, wherein the ultrafine metal particles have an average particle size of 100 nm or less.   The metal ultrafine particles are at least one metal selected from the group consisting of gold, silver, copper, palladium, tin, platinum, tungsten, nickel, tantalum, indium, zinc, titanium, chromium, iron and cobalt, or these The method for forming a conductive film according to claim 1, wherein the metal alloy is an ultrafine particle of an alloy or oxide of the above.   An electrode comprising the conductive film formed by the method according to claim 1.