| 摘要 |
PROBLEM TO BE SOLVED: To improve the failure detecting ratio of a part having poor observability by probing it twice by one rate of a test pattern. SOLUTION: An optional signal line in a circuit to be inspected is taken as a failure observing position for observing the influence of a failure propagated to the signal line, and an EXOR tree circuit 106 for inputting signal lines 102-104 as the failure observing position is formed. A selector 108 for inputting the output of the EXOR tree circuit 106 and selectively inputting an external input pin 110 is interposed between the circuit to be inspected and the external output pin. For a degeneracy failure assumed in an order circuit which is the circuit to be inspected, the influence of this failure can be easily observed by an external output pin 107. |
