Provided is copper paste for joining including metal particles, and a dispersion medium. The metal particles include sub-micro copper particles having a volume-average particle size of 0.12 m to 0.8 m, and micro copper particles having a volume-average particle size of 2 m to 50 m, a sum of the amount of the sub-micro copper particles contained and the amount of the micro copper particles contained is 80% by mass or greater on the basis of a total mass of the metal particles, and the amount of the sub-micro copper particles contained is 30% by mass to 90% by mass on the basis of a sum of a mass of the sub-micro copper particles and a mass of the micro copper particles.

A semiconductor device includes an insulating substrate, a first and a second obverse-surface metal layers disposed on an obverse surface of the insulating substrate, a first and a second reverse-surface metal layers disposed on a reverse surface of the insulating substrate, a first conductive layer and a first semiconductor element disposed on the first obverse-surface metal layer, and a second conductive layer and a second semiconductor element disposed on the second obverse-surface metal layer. Each of the first conductive layer and the second conductive layer has an anisotropic coefficient of linear expansion and is arranged such that the direction in which the coefficient of linear expansion is relatively large is along a predetermined direction perpendicular to the thickness direction of the insulating substrate. The first and second reverse-surface metal layers are smaller than the first and second obverse-surface metal layers in dimension in the predetermined direction.

Provided is copper paste for joining including metal particles, and a dispersion medium. The metal particles include sub-micro copper particles having a volume-average particle size of 0.12 m to 0.8 m, and micro copper particles having a volume-average particle size of 2 m to 50 m, a sum of the amount of the sub-micro copper particles contained and the amount of the micro copper particles contained is 80% by mass or greater on the basis of a total mass of the metal particles, and the amount of the sub-micro copper particles contained is 30% by mass to 90% by mass on the basis of a sum of a mass of the sub-micro copper particles and a mass of the micro copper particles.

Provided is copper paste for joining including metal particles, and a dispersion medium. The metal particles include sub-micro copper particles having a volume-average particle size of 0.12 m to 0.8 m, and micro copper particles having a volume-average particle size of 2 m to 50 m, a sum of the amount of the sub-micro copper particles contained and the amount of the micro copper particles contained is 80% by mass or greater on the basis of a total mass of the metal particles, and the amount of the sub-micro copper particles contained is 30% by mass to 90% by mass on the basis of a sum of a mass of the sub-micro copper particles and a mass of the micro copper particles.