Patent ID: 8021580
Filing Date: 2011-09-20
Classification: C08K,H01B,Y10S,Y10T

Abstract:
1. A conductive metal paste available for forming a metalic thin film layer of a metal fine particle sintered product on a surface of a substrate, characterized in that: a silanol structure (Si—O—H) exists on the surface of the substrate, the conductive metal paste is free from any resin; the conductive metal paste comprises metal fine particles having a fine average particle size dispersed uniformly in a dispersion solvent, one or more metal compounds, and an amine-based solvent capable of solving the one or more metal compounds; the conductive metal paste is free from any metal particle other than the metal fine particles; the average particle size for the metal fine particles having a fine average particle size is selected within a range from 1 nm to 20 nm; a surface of the metal fine particles is coated with one or more compounds having a group that contains a nitrogen, oxygen, or sulfur atom and is capable of coordinate bonding via a lone pair held by the atom, as a group capable of coordinate bonding with a metal element contained in the metal fine particles; metal species (M) contained in the one or more metal compounds are selected from the group consisting of copper and bismuth which exhibit adhesion to a material constituting a surface of the substrate; the conductive metal paste comprises 10 to 60 parts by mass in total of the one or more compounds having a group that contains a nitrogen, oxygen, or sulfur atom with respect to 100 parts by mass of the metal fine particles; the conductive metal paste comprises the one or more metal compounds such that a ratio of metals contained in the one or more metal compounds to 100 parts by mass of the metal fine particles is 0.3 to 7 parts by mass in total; a blending ratio of the amine-based solvent capable of solving the one or more metal compounds is selected such that the amine-based solvent is within a range from 100 to 500 parts by mass per 10 parts by mass in total of the metals contained in the one or more metal compounds; and the conductive metal paste comprises, as the dispersion solvent, one or more organic solvents which can solve the one or more compounds having a group containing a nitrogen, oxygen, or sulfur atom and which can uniformly dilute a solution comprising the metal compound and the amine-based solvent capable of solving the metal compound as well, wherein the metal species constituting the metal fine particles whose average particle size is selected within a range from 1 nm to 20 nm is a metal species selected from the group consisting of gold, silver, copper, platinum, and palladium, or an alloy of two or more thereof, the one or more compounds having the group that contains a nitrogen, oxygen, or sulfur atom are selected from the group consisting of primary alkyl amines whose alkyl group has C8 to C18, the metal compound is a metal compound comprising an organic anion species and a metal cation species whose oxidation number is 2, the organic anion species is selected from the group consisting of 2,4-pentanedionate ([CH the metal species (M) used as the metal cation species whose oxidation number is 2 is a metal more base than the metal species constituting the metal fine particles, and is capable of being immobilized in the form of Si—O-M to the silanol structure (Si—O—H), in the conducive metal paste, the metal compound is comprised in the solution form, the amine-based solvent capable of solvating the one or more metal compounds is an amine-based solvent having a boiling point within a range from 150° C. to 300° C. which is selected from the group consisting of alkyl amines and polyamines, and the organic solvent used as the dispersion solvent is an organic solvent having a relatively high boiling point which is selected from the group consisting of non-polar solvents.