Conductive composition for bonding, bonding structure using same, and manufacturing method thereof
A conductive composition for bonding includes a mix of copper powder carboxylic acid. The carboxylic acid has a branched carbon chain. The copper powder comprises first and second copper particles. The first copper particles have a volume-based cumulative particle size D 50 of 0.11 μm or more and less than 1 μm at a cumulative volume of 50 vol % in a region of particle sizes of less than 1 μm in a particle size distribution of the copper powder. The second copper particles have a volume-based cumulative particle size D 50 of 1 μm or more and 10 μm or less at a cumulative volume of 50 vol % in a region of particle sizes of 1 μm or more in the particle size distribution of the copper powder. The carboxylic acid is contained in an amount of 6 parts or more and 24 parts or less per 100 parts by mass.
1 . A conductive composition for bonding, comprising a copper powder and a carboxylic acid mixed therewith,
wherein
the carboxylic acid has a branched carbon chain in its structure,
the copper powder comprises first copper particles and second copper particles, a percentage of the first copper particles being 30 to 95 mass % relative to a total mass of the first and second copper particles, wherein,
the first copper particles have a volume-based cumulative particle size D 50 of 0.11 μm or more and less than 1 μm at a cumulative volume of 50 vol % in a region of particle sizes of less than 1 μm in a particle size distribution of the copper powder that is determined using a scanning electron microscope, and
the second copper particles have a volume-based cumulative particle size D 50 of 1 μm or more and 10 μm or less at a cumulative volume of 50 vol % in a region of particle sizes of 1 μm or more in the particle size distribution of the copper powder that is determined using the scanning electron microscope, and
the carboxylic acid is contained in an amount of 6 parts by mass or more and 24 parts by mass or less per 100 parts by mass of the copper powder.
2 . The conductive composition for bonding as set forth in claim 1 , wherein the carboxylic acid is an aliphatic monovalent carboxylic acid having 4 to 18 carbon atoms.
3 . The conductive composition for bonding as set forth in claim 1 , wherein the carboxylic acid is a tertiary carboxylic acid.
4 . The conductive composition for bonding as set forth in claim 1 , wherein the carboxylic acid is liquid at 1 atm and 20° C.
5 . The conductive composition for bonding as set forth in claim 1 , wherein the carboxylic acid is neodecanoic acid.
6 . A bonded structure comprising a first conductor, a second conductor, and a bonding portion with which the first conductor and the second conductor are bonded to each other,
wherein the bonding portion comprises a sintered body of the conductive composition for bonding as set forth in claim 1 .
7 . A method for producing a bonded structure, comprising
a step of interposing the conductive composition for bonding as set forth in claim 1 between two conductors, and
a step of sintering the conductive composition for bonding.