Low-temperature low-pressure bonding by nanocomposites

Abstract

It has been proposed that Cu-Ag alloys exhibit longer eletromigration life time than Cu as well as superior electrochemical migration resistance than Ag. Our group developed a new kind of Cu-Ag composite paste which is capable of achieving bonding at low processing temperatures under low bonding pressure. It comprises carboxylate-coated Ag nanoparticles, spary-pyrolyz ed Ag submicron particles and copper formate, which can be applied to interconnection and bonding as well. After being bonded at 160°C under loading of 1.6 MPa for 30 min, the joints with Cu substrates possess bonding strength of 15.9MPa and those with Ag surface finish showing shear strength of 19.4 MPa. The electrical resistivity of the sintered structure thus obtained is 50.8 μΩ-cm.