PURPOSE: To diagnose a fixed failure such as a short circuit, a disconnection or the like and a transient failure such as a delay without a need for a failure dictionary and a special test circuit by a method wherein an operating waveform of an integrated circuit is observed by using an electron beam tester and this observed waveform is compared with an expected waveform formed by a simulation.
CONSTITUTION: A test pattern is input to an input terminal of an integrated circuit to be diagnosed; this observed waveform is compared with an expected waveform by a logical simulation; when they do not coincide, a flip-flop(FF) to which this signal is coupled by using this disagreement as a malfunction output terminal is found from a logical connection file; this output signal is observed by using a noncontact tester 4; this observation is compared with an expected waveform; the FF of the disagreement is regarded as a malfunction FF; in addition, its input source FF is checked; the malfunction FF is found. Then, a malfunction about an input signal of a gate circuit connected directly to this input signal is found; a failure part is detected.
SATO TSUKASA
HAGIWARA YOSHIMUNE
