Joint structure
A bonded structure is a structure in which two bonding target members and a bonding portion formed between and adjacent to the bonding target members are bonded together. The bonding portion is made of a material mainly containing copper. In a cross section of the bonded structure taken along a thickness direction, a ratio of a bonded rate between the bonding target members and the bonding portion in a peripheral region of the bonded structure to a bonded rate between the bonding target members and the bonding portion in a central region of the bonded structure is from 0.6 to 0.9. The bonded rate is 0.3 or more.
1 . A bonded structure in which two bonding target members and a bonding portion formed between and adjacent to the bonding target members are bonded together,
wherein the bonding portion comprises a sintered body of copper particles containing spherical copper particles and flake-like copper particles,
a ratio (Rs/Rc) of a bonded rate Rs between the bonding target members and the bonding portion in a peripheral region of the bonded structure to a bonded rate Rc between the bonding target members and the bonding portion in a central region of the bonded structure is from 0.6 to 0.8, in a cross section of the bonded structure taken along a thickness direction thereof,
the bonded rate Rc is 0.3 or more, and
the bonded rate Rs is 0.35 or more and 0.55 or less,
wherein a temperature increase rate during sintering is 120 to 2000° C./min.
2 . The bonded structure according to claim 1 , wherein a surface of at least one of the bonding target members contains at least one metal selected from gold, silver, copper, nickel, and titanium.
3 . The bonded structure according to claim 1 , wherein the bonding portion comprises a compound with a structure represented by Formula (1) below:
in Formula (1), R 3 to R 5 each independently represent a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having a hydroxyl group, and
* represents a copper-binding site.
4 . The bonded structure according to claim 1 , wherein the copper particles are comprised of 70% of the spherical copper particles and 30% of the flake-like copper particles.
5 . The bonded structure according to claim 1 , wherein a particle size of the spherical copper particles lies in a range of 0.03 microns or more.
6 . The bonded structure according to claim 1 , wherein a particle size of the flake-like copper particles lies in a range of 0.3 microns or more.
7 . The bonded structure according to claim 1 , wherein the bonded rate Rc is 0.4 or more.
8 . The bonded structure according to claim 1 , wherein the bonded rate Rc is 0.5 or more.
9 . The bonded structure according to claim 1 , wherein the bonded rate Rs is 0.35 or more and 0.5 or less.