A new Ag paste composed of nano- and micro-Ag particles prepared simultaneously and its application as dieattachment materials

摘要

Although nano-Ag was developed to attach a die to substrates, and high performance in joint strength and electronic conductivity were realized, the complicated synthesis process and low yield of nano-Ag, and high joint pressure and temperature largely limited the application of nano-Ag in the industry. Here, a simple two-step polyol process was used to simultaneously synthesize nano and micro-Ag particles in large-scale and high-yield. The size and size distribution of Ag particles depended on the reaction parameters. These Ag particles were used to make hybrid Ag pastes to joint Cu sheets. Shear strengths over 40 and 52 MPa were achieved by using an Ag paste composed of nano-Ag particles and micro-Ag particles under