Fault diagnosis apparatus and recording medium with a fault diagnosis program recorded thereon

A fault diagnosis apparatus which estimates a fault site in a fault diagnosis object LSI based on a result of an LSI test performed using a test pattern for the LSI, comprising:

• suspected fault gate setting means for setting candidates for a suspected fault gate to a suspected fault gate set;
• and
• branch destination fault simulation narrowing down means for defining a 1/0 stuck-at fault to each of output branch destinations of the suspected fault gates included in the suspected fault gate set and performing a fault simulation for each one test pattern, removing, for each fault simulation, the fault definitions of output branch destinations detected with normal outputs, and removing those of the suspected fault gates from which the fault definitions of all of the respective output branch destinations have been removed and those of the suspected fault gates with which, in any of the error test patterns, none of the fault definitions of the respective output branch destinations have not been detected with outputs which are determined to be errors with the error test pattern from the suspected fault gate set.

A recording medium having recorded thereon a fault diagnosis program for estimating a fault site in a fault diagnosis object LSI based on a result of an LSI test performed using a test pattern for the LSI, the fault diagnosis program causing a computer to execute:

• a first step of setting candidates of a suspected fault gate to a suspected fault gate set;
• and
• a second step of checking, for each of the suspected fault gates included in the suspected fault gate set, whether or not a condition is satisfied that an output value of the suspected fault gate at least in an error test pattern is different from that of the suspected fault gate in the other error test patterns, and removing those of the suspected fault gates with which the condition is satisfied from the suspected fault gate set.

A recording medium having recorded thereon a fault diagnosis program for estimating a fault site in a fault diagnosis object LSI based on a result of an LSI test performed using a test pattern for the LSI, the fault diagnosis program causing a computer to execute:

• a first step of setting candidates of a suspected fault gate to a suspected fault gate set;
• and
• a third step of defining a 1/0 stuck-at fault to each of output branch destinations of the suspected fault gates included in the suspected fault gate set and performing a fault simulation for each one test pattern, removing, for each fault simulation, the fault definitions of output branch destinations detected with normal outputs, and removing those of the suspected fault gates from which the fault definitions of all of the respective output branch destinations have been removed and those of the suspected fault gates with which, in any of the error test patterns, none of the fault definitions of the respective output branch destinations have not been detected with outputs which are determined to be errors with the error test pattern from the suspected fault gate set.