A microwave plasma dry etch technique for failure analysis of Cu and PdCu wire bonds strength

A dry etching de-capsulation method using pre-laser ablation, microwave plasma etching and diluted methane sulfonic acid cleaning to expose the Cu wire is introduced. Comparison study of wire bond strength shows that dry plasma etching is superior over wet chemical etching method. The experiment leads further to determine the characterization result of wire ball bonding strength for different bond pads and wire materials of samples produced by the two types of de-capsulation method.