Abstract Soft defect localization (SDL) is a method of laser scanning microscopy that utilizes the changing pass/fail behavior of an integrated circuit under test and temperature influence. Historically the pass and fail states are evaluated by a tester that leads to long and impracticable measurement times for dynamic random access memories (DRAM). The new method using a high speed comparison device allows SDL image acquisition times of a few minutes and a localization of functional DRAM fails that are caused by defects in the DRAM periphery that has not been possible before. This new method speeds up significantly the turn-around time in the failure analysis (FA) process compared to knowledge based FA.