Harima Chemicals, Incorporated

National Institute of Advanced Industrial Science and Technology

Sijtechnology, Inc.

Akihito Izumitani

Daisuke Itoh

Yorishige Matsuba

Noriaki Hata

Hiroshi Yokoyama

Kazuhiro Murata

According to the present invention, a metal nanoparticle dispersion suitable to multiple layered coating by jetting in the form of fine droplets is prepared by dispersing metal nanoparticles having an average particle size of 1 to 100 nm in a dispersion solvent having a boiling point of 80&#xb0; C. or higher in such a manner that the volume percentage of the dispersion solvent is selected in the range of 55 to 80% by volume and the fluid viscosity (20&#xb0; C.) of the dispersion is chosen in the range of 2 mPa&#xb7;s to 30 mPa&#xb7;s, and then when the dispersion is discharged in the form of fine droplets by inkjet method or the like, the dispersion is concentrated by evaporation of the dispersion solvent in the droplets in the course of flight, coming to be a viscous dispersion which can be applicable to multi-layered coating.

Metal nanoparticle dispersion usable for ejection in the form of fine droplets to be applied in the layered shape

The present invention provides a process for forming a copper fine particle sintered product type of a fine-shaped electric conductor showing superior electroconductivity, which comprises steps of drawing a fine pattern with the use of a dispersion containing the copper fine particles having a surface oxide film layer, conducting a treatment for reducing the copper fine particles with the surface oxide film layer or copper oxide fine particles included in the pattern at a comparatively low temperature, and baking the resultant copper fine particles. Specifically, the process carries out the processes of; applying a dispersion containing the copper fine particles having the surface oxide film layer thereon or the copper oxide fine particles with an average particle diameter of 10 &#x3bc;m or smaller onto a substrate; and then performing a series of the heat treatment steps of heating the particles in the coated layer at temperature of 350&#xb0; C. or lower under an atmosphere containing a vapor and a gas of a compound having reducibility to reduce the oxide film by a reduction reaction which used the compound having reducibility as a reducing agent, subsequently repeating a heat treatment combining an oxidizing treatment of a short time with a re-reducing treatment, and sintering the resultant copper fine particles with each other to form a layer of the sintered product.

Method for forming fine copper particle sintered product type of electric conductor having fine shape, and process for forming copper fine wiring and thin copper film by applying said method

Growing community of inventors

Ibaraki, Japan

Akihito Izumitani