Development of conductivity in low conversion temperature silver pastes via addition of nanoparticles

Silver nanoparticles were incorporated in a dispersion of micron-sized silver spheres for testing as a low-temperature reactive component to form conductive particle networks. The development of conductivity depended on the arrangement of the micron-sized particle network, the amount of material reacted to form necks at the points of contact of micron-sized particles, and sintering of the particle network. Nanoparticles reacted to bond the micron-sized particles, but the stress issues involved in nanoparticle sintering can cause macroscopic cracking. Critical processing variables include the state of particle dispersion, the heating rate, and the fraction of nano-sized material.