Method for producing a copper fine particle dispersion aqueous solution, and storing method of the copper fine particle dispersion solution

PROBLEM TO BE SOLVED: To provide a copper fine particle dispersion aqueous solution capable of obtaining a conductive member having excellent conductivity and a small amount of impurities even when being applied, dried and fired at a relatively low temperature and having high dispersibility. SOLUTION: The method of preparing the copper fine particle dispersion aqueous solution in which copper fine particles having 1-150 nm average particle diameter of primary particles and having the surface at least partially covered with a dispersing agent are dispersed in an aqueous solution, includes a step (step 1) of: (i) obtaining a water soluble copper ammine complex by the reaction of copper ion with ammonia in an ammonia aqueous solution adjusted to ≥pH9.2 with a pH adjuster in the presence of the dispersing agent; and a step (step 2) of: (ii) forming the copper fine particles having the surfaces at least partially covered with the dispersing agent by an electrolytic reduction reaction in a reduction reaction aqueous solution containing the copper ammine complex obtained in the step 1. In the reduction reaction system, a compound containing atoms except copper, carbon atom, hydrogen atom, oxygen atom and nitrogen atom is not contained. COPYRIGHT: (C)2010,JPO&INPIT