INSPECTION OF HIGH SPEED MEMORY ELEMENT IN WHICH CLOCK USE LIMIT CONDITIONS ARE SET

摘要

PROBLEM TO BE SOLVED: To inspect high speed memory element by using a low speed inspection device by adjusting a shift signal for controlling a driver switch and a comparator switch within a fixed limit condition, widening a usable region of a strobe signal making a comparator unable to be used, and setting a new limit condition for a clock signal used at each inspection cycle. SOLUTION: A data input/output pin DQ of an inspection objective element DUT is coupled to I/O of an inspection device and drivers 10, VOH, VOL and comparators 20, 22 on a circuit substrate 100 for driver. A comparison time of comparators 20, 22 is decided by a strobe signal inputted through the second skew adjusting circuit 26, but there is a non-use region being a timing period in which a strobe signal cannot be used. A shift signal widens a usable range of a strobe signal by moving such a non-use region. Thereby, the inspection objective element 40 having high speed can be inspected by a low speed inspection device, and facility investment can be largely reduced.