Abstract

This research was successful in developing a metal protection mechanism for ammonium bifluoride clean agent that is used in wafer dicing processes, during which metals from IC trace (Al, Cu) and from bumping process (Ti, TiW, Cu, Sn, Ag, etc.) will be exposed. All metals must be protected from the cleaning agent used; any metal corrosion may cause IC to fail or lead to instability, especially when HF molecules are small and can easily dissociate in water. This research showed that the water ratio in the cleaning agent was the main factor that caused metal corrosion. 95% alcohol was then used to replace water in the cleaning agent, and we were able to get a good control of metal corrosion during the cleaning of Si contaminants. These results led to the development of a cleaning agent that could be directly used in the wafer dicing process. In this study, we used bump shear strength as an index of UBM corrosion and got a very quick and correct result.

Keywords:Metal protection; Wafer dicing; Cleaning; Silicon contamination; Ammonium bifluoride