A back side failure analysis flow has been developed in order to enable failure analysis of flip-chip, leadon- chip dies and within multi-metal-level dies. A combination with frontside failure analysis methods is possible too. The back side flow consists of stepwise bulk silicon removal, electrical and physical failure analysis methods. Four different methods for bulk silicon thinning in order to localize electrical defects using PEM are compared. A method to remove the bulk silicon after PEM analysis to expose the gate oxide level of a die has been developed. Different back side applications like physical analysis of gate oxide defects, passive voltage contrast and microprobing with an AFM tip for detection of interrupts within conductive interconnects are described.