Interfacial Nano-Mechanical Properties of Copper Joints Bonded with Silver Nanopaste near Room Temperature

Sintering of nanomaterials at low temperatures has been demonstrated as an alternative for flexible electronic packaging. Silver nanowires were synthesized via polyol method and used as filler material for bonding copper to copper near room temperature. The experimental results indicated that both silver-to-silver and copper-to-silver formed metallurgical bonds. The elastic modulus and nano-hardness of copper joints at the copper-silver interface were characterized using nanoindentation. A transition layer at the interface was observed and its thickness was determined. Sintered silver filler material showed good elasticity both inside and out of the transition layer.