Correlation between intermetallic thickness and roughness during solder reflow

Abstract

The evolution of Cu-Sn and Ni-Sn intermetallic compound (IM) morphologies during isochronal reflow of a PbSn solder with Cu and electroless-Ni was investigated. The root mean square roughness of the Cu-Sn and Ni-Sn IM layers exhibited a linear dependence on average thickness, with gradients () of 0.33 and 0.65, respectively. The difference in values was attributed to different thickness distributions resulting from morphological dissimilarity of the IM layers. The apparent activation energies for growth and roughness evolution of both IM were found to be similar and suggest that both IM thickness and roughness evolution are controlled by the same mechanism. © 2001 TMS-The Minerals, Metals and Materials Society.