Abstract: In a conductive film forming method using photo sintering, a conductive film having low electric resistance is easily formed. Disclosed is a conductive film forming method in which a conductive film is formed using a photo sintering, which includes the steps of: forming a liquid film made of a copper particulate dispersion on a substrate, drying the liquid film to form a copper particulate layer, subjecting the copper particulate layer to photo sintering to form a conductive film, attaching a sintering promoter to the conductive film, and further subjecting the conductive film having the sintering promoter attached to photo sintering. The sintering promoter is a compound which removes copper oxide from metallic copper. Thereby, the sintering promoter removes a surface oxide film of copper particulates in the conductive film.

Abstract: The copper particulate dispersion includes copper particulates, at least one kind of a dispersion vehicle containing the copper particulates, and at least one kind of dispersant which allows the copper particulates to disperse in the dispersion vehicle. The copper particulates have a center particle diameter of 1 nm or more and less than 100 nm. The dispersion vehicle is a polar dispersion vehicle. The dispersant is a compound having at least one acidic functional group, which has a molecular weight of 200 or more and 100,000 or less, or a salt thereof. Whereby, the dispersant has compatibility with dispersion vehicle and a surface of copper particulates is coated with dispersant molecules, and thus the copper particulates are dispersed in the dispersion vehicle.

Abstract: To provide copper particulate dispersion capable of forming a conductive film having favorable adhesiveness on an inorganic substrate by photo-sintering. The copper particulate dispersion includes a dispersion vehicle and copper particulates RUM The copper particulates are dispersed into the dispersion vehicle. The copper particulate dispersion includes an adhesion improvement agent for improving adhesiveness between a conductive film formed on a substrate by photo-sintering the copper particulate and the substrate. The substrate is an inorganic substrate. The adhesion improvement agent is a compound containing a phosphorus atom. Thus, the adhesion improvement agent improves adhesiveness between the conductive film and the inorganic substrate.

Abstract: Provided is a copper particulate dispersion that can facilitate the formation of a conductive film with low electric resistance by photo-sintering. A copper particulate dispersion includes a dispersion vehicle and copper particulates dispersed in the dispersion vehicle. The copper particulate dispersion contains a sintering promoter. The sintering promoter is a compound that removes copper oxide from copper at a temperature higher than ambient temperature. The sintering promoter thereby removes surface oxide coatings from the copper particulates during the photo-sintering of the copper particulates.

Abstract: An object is to provide a copper particulate dispersion which is suited to discharge in the form of droplets. The copper particulate dispersion includes copper particulates, at least one kind of a dispersion vehicle containing the copper particulates, and at least one kind of dispersant which allows the copper particulates to disperse in the dispersion vehicle. The copper particulates have a center particle diameter of 1 nm or more and less than 100 nm. The dispersion vehicle is a polar dispersion vehicle having a boiling point within a range from 150° C. to 250° C. Whereby, when the copper particulate dispersion is discharged in the form of droplets, clogging at the discharge portion caused by drying of the dispersion vehicle is prevented and the viscosity is low for its high boiling point, and thus the copper particulate dispersion is suited to discharge in the form of droplets.

Abstract: In a conductive film forming method using photo sintering, a conductive film having low electric resistance is easily formed. Disclosed is a conductive film forming method in which a conductive film is formed using a photo sintering, which includes the steps of: forming a liquid film made of a copper particulate dispersion on a substrate, drying the liquid film to form a copper particulate layer, subjecting the copper particulate layer to photo sintering to form a conductive film, attaching a sintering promoter to the conductive film, and further subjecting the conductive film having the sintering promoter attached to photo sintering. The sintering promoter is a compound which removes copper oxide from metallic copper. Thereby, the sintering promoter removes a surface oxide film of copper particulates in the conductive film.

Abstract: In a conductive film forming method using photo sintering, a conductive film having low electric resistance is easily formed. The conductive film forming method is a method in which a conductive film is formed using photo sintering. This method includes the steps of forming a layer made of a sintering promoter on a substrate, forming a liquid film made of a copper particulate dispersion on the layer of the sintering promoter, drying the liquid film to form a copper particulate layer, and subjecting the copper particulate layer to photo sintering. The sintering promoter is a compound which removes copper oxide from metallic copper. Thereby, the sintering promoter removes a surface oxide film of copper particulates in photo sintering.

Abstract: In a conductive film formed by photo sintering of a film composed of copper particulates, adhesiveness to a base material of the conductive film is improved. A circuit board includes a circuit including a conductive film, and a substrate. The circuit board further includes a resin layer between the substrate and the conductive film. The substrate is made of a non-thermoplastic base material. The resin layer contains a thermoplastic resin. The conductive film is formed by photo sintering of a film composed of copper particulates, and thus improving adhesiveness of the conductive film to the base material through the resin layer.

Abstract: An object is to provide the formulation of a copper particulate dispersion in which copper particulates are dispersed. The copper particulate dispersion includes copper particulates, at least one kind of a dispersion vehicle containing the copper particulates, and at least one kind of dispersant which allows the copper particulates to disperse in the dispersion vehicle. The copper particulates have a center particle diameter of 1 nm or more and less than 100 nm. The dispersion vehicle is a polar dispersion vehicle. The dispersant is a compound having at least one acidic functional group, which has a molecular weight of 200 or more and 100,000 or less, or a salt thereof. Whereby, the dispersant has compatibility with dispersion vehicle and a surface of copper particulates is coated with dispersant molecules, and thus the copper particulates are dispersed in the dispersion vehicle.

Abstract: An object is to provide a conductive film forming method which can form a conductive film having low electric resistance on a base material by utilizing photo sintering even when the base material has low heat resistance. A conductive film forming method is a method in which a conductive film is formed on a base material, and the method includes the steps of forming a film composed of copper particulates on a base material, subjecting the film to photo sintering, and applying plating to the photo-sintered film. Whereby, it is possible to form a conductive film on a base material by lowering irradiation energy of light in photo sintering even when the base material has low heat resistance. Since the conductive film includes a plated layer, electric resistance decreases.

Abstract: An object is to provide a copper particulate dispersion which is suited to discharge in the form of droplets. The copper particulate dispersion includes copper particulates, at least one kind of a dispersion vehicle containing the copper particulates, and at least one kind of dispersant which allows the copper particulates to disperse in the dispersion vehicle. The copper particulates have a center particle diameter of 1 nm or more and less than 100 nm. The dispersion vehicle is a polar dispersion vehicle having a boiling point within a range from 150° C. to 250° C. Whereby, when the copper particulate dispersion is discharged in the form of droplets, clogging at the discharge portion caused by drying of the dispersion vehicle is prevented and the viscosity is low for its high boiling point, and thus the copper particulate dispersion is suited to discharge in the form of droplets.