Effect of additional elements on growth rate of intermetallic compounds at copper/solder interface

摘要

The effect of several factors on the growth rate of intermetallic compounds formed at soldered copper was investigated by holding at 353-423K. The compounds were ε- Cu{sub}3Sn and η - Cu{sub}6Sn{sub}5 from copper side to solder. They grew in proportion to the square root of the holding time. The thickness ratio of these compounds formed on pure copper were almost constant irrespective of heat treatment and cold rolling conditions for copper. The addition of elements of about 1at% to copper greatly influenced on the growth rate and the thickness ratio of the thickness of compounds. There was no elements to suppress the compound formation effectively. The addition of the following elements gave little or a little suppression on the thickness of compounds; Mg, Cr, Mn, Ag and Sn. Ti and Ni could be also included in this group, however, they produced cracks at the soldered interface. All other elements enhanced the growth of compounds, especially, P and Pt showed large growth in thickness. The addition of the following elements formed cracks and/or voids at soldered interface; Al, Si, P, Fe, Co, Pd and Pt. The apparent activation energy for the growth of intermetallic compounds were from 40-120kJ/mol depending on the additional elements.