Silicon Precipitates Counts and Size Study in Aluminium Bond Pads

(Al) based metallization has been widely used in semiconductor due to the process ability and the material behavior. However, pure Al based material cannot be used due to the hillock issue, void formation and also Al spiking caused by interaction with silicon. Thus, small amount of Copper (Cu) and Silicon (Si) precipitates were introduced into the Al layer to resolve these issues. Nowadays the bond pads metallization has becoming thinner owing to the recent semiconductor needs thus the presence of big Si precipitates will have risk leading to cratering issue in wire-bonding process. Here in, we report for the first time on how to quantify the Si precipitates counts and Si precipitates size in Al based metallization through failure analysis methods.