The interface behavior of the Cu-Al bond system in high humidity conditions

Copper (Cu) wire has been highlighted as a low cost material for use in thermosonic ball bonding for various package (PKG) groups. This wire has already been applied in high-end PKGs such as BGA, QFP and QFN in mass production, and the volume is feasible. Not only the advantage of a low cost material, but Cu wire has other merits which include higher electrical conductivity and a much slower inter-metallic compound (IMC) growth rate than Gold (Au) wire.