Low temperature sintering of Ag nanoparticles for flexible electronics packaging

We achieve robust bonding of Cu wires to Cu pads on polyimide with silver nanopaste cured at 373 K. The paste is prepared by simply condensing Ag nanoparticle (NP) solution via centrifuging. The bonding is formed by solid state sintering of Ag NPs through neck growth and direct metallic bonding between clean Ag–Cu interfaces. Both experiment and Monte Carlo simulation confirm that the melting point of joint clusters increases during sintering. This creates improved bonds for use at an elevated operating temperature using Ag NPs.