An in-situ resistance measurement to extract IMC resistivity and kinetic parameter of alternative metallurgies for 3D stacking

Abstract

In this work, an in-situ resistance measurement method is proposed to investigate the interfacial solid state reaction of alternative metallurgies, such as Ni and Cu/Ni as UBM materials, with Sn solders. The electrical properties of formed IMC phases for different metallurgies systems are extracted and discussed. Kinetic parameters, such as activation energy and power factor, of Ni/Sn and Cu/Ni/Sn solid-state reaction are extracted from in-situ resistance measurement. Power factor of Ni/Sn and Cu/Ni/Sn kinetic reaction indicate that the IMC evolution behaviors involve bulk diffusion-controlled (the time exponent n = 0.5) for Ni/Sn, while the growth evolution of (Cu,Ni)6Sn5 in Cu/Ni/Sn solid state reaction involves grain-boundary diffusion controlled (the time exponent n = 0.33) from in-situ resistance measurement. This proposed in-situ measurement methodology has the advantages of being quick and accurate to understand and characterize the reaction and phase formation between UBM and solder materials for 3D applications.