| 摘要 |
PURPOSE:To make a rapid trouble diagnosis feasible by a method wherein the titled device is constituted to resume impression of an input wave form pattern from the top thereof whenever an output wave form pattern with differ ent value from the expected value thereof is detected. CONSTITUTION:A wave form generator 6 generates a timing trigger 4 when a specific input wave form pattern 3 is impressed on an IC2 while resuming impressing from the top of input wave form pattern when said generator 6 receives a discrepancy detecting trigger 5. A comparator 8 compares an output wave form pattern 7 with the expected value thereof to generate the discrepancy detecting trigger 5 whenever any discrepancy is detected. The surface of IC chip 2 is irradiated with scanning pulse electron beams 9 synchronized with the timing trigger 4 to detect any secondary electrons generated by a detector 12 making a storage 15 store the secondary electron signals and the location data on irradiation points of electron beams on the surface of IC chip 2. Through these procedures, any potential distribution on the surface of IC chip 2 in case of a specific input wave form pattern 3 may be detected by the data stored in the storage 15. |
