Tuning the electrical resistivity of conductive silver paste prepared by blending multi-morphologies and micro-nanometers silver powder

As an important interconnection material in electronics, conductive silver paste has attracted much research interest in chip packaging and printed circuit board due to its predominant properties like high conductivity and flexible interconnection. In this paper, the silver nanoparticles, the silver sphere particles, and flake silver powders are fabricated by various methods. Different proportions of silver powder are selected to prepare micro-silver paste and micro-nano (mn) silver paste (fabricated by silver nanoparticles:sphere particles:flake silver powder = 1:1:1). Compared to traditional silver paste with high silver content (containing 80 wt% silver), paste in this work contains only 66.67 wt% silver. When the ratio of sphere particle to flake silver powder is 1:1, the electrical resistivity of micro-silver paste cured at 200 °C for 45 min in air is about (3.31 ± 0.73) × 10 −5  Ω cm, the resistance of silver paste rises a little bit after being folded by ten times. The addition of nano-silver particles can reduce the resistivity in lower temperature curing. The folding endurance of mn silver paste is comparable to that of micro-silver paste with sphere:flake = 1:1.