Wire bonding, bumping & assembly related failures & improvements

In this paper, investigation of wire bonding, bumping and assembly related failures are performed using optical microscopy, secondary electron microscopy and transmission electron microscopy. Also, the understandings of the failures and root causes are presented. For example, corrosions caused by contaminant such as Fluorine and Cu precipitates on Al-Cu alloyed bond pads that lead to discolored or non-stick on pads problem are discussed. In addition, the formation of small bumps when oxide/silicon nitride passivation is employed and chipping at die edges caused during assembly that leads to open-circuit are studied. In conclusion, possible solutions of these failures are recommended to achieve robust assembly and packaging.