Focused ion beam in failure analysis of microelectronic devices

In this paper, two case studies will be presented to demonstrate the applications of FIB technique in in-line defect analyses of microelectronic devices. The in-line defects were first detected during wafer processing by automatic inspection equipment. The inspection data of detect type, size and coordinates were converted and loaded to the FIB control system so that the defects were able to be precisely located in the FIB for further analysis. Cross sectioning through the defects was performed in the FIB to obtain information about the defects. In the two cases presented here, the defects were found to be associated with the tunnels in the dielectric layers between the metal lines. Due to the small dimensions and irregular geometry of the defects, FIB has proved its important capability in defect analysis which enabled us to track down the root cause of defects.