A rapid chemical diagnostic method to detect silicon oxide and TiN residues on aluminum bondpads in wafer fabrication

Silicon oxide and TiN residues on Al bondpads will result in non-stick bondpad problem at assembly process. Currently, EDX and Auger analysis techniques are used to determine silicon oxide and TiN residues and monitor quality of bondpads. However, EDX and Auger analysis techniques are not very common tools. Auger analysis has a long cycle time and is also costly. Therefore, it is necessary to develop a rapid diagnostic method with low cost to detect silicon oxide and TiN residues on Al bondpads. In this paper, a chemical diagnostic method using KOH (Potassium Hydroxide) testing will be introduced. After characterization, a new KOH testing method is developed and applied in failure analysis of non-stick bondpad issues. The analytical results show that the KOH testing is a rapid and effective method to detect silicon oxide and TiN residues on Al bondpads.