With the miniaturization of semiconductor integrated circuits, fluctuation of leak current consequent to processing has increased. Leak current is current that flows through a place where the current is not supposed to flow. Leak current aggravates power consumption and heat emission of a circuit, lowering the performance of the circuit. Thus, it is important to correctly estimate leak current when the circuit is designed and to take measures against leak current.
One method for estimating leak current taking account of fluctuation of the leak current is statistical leak current analysis. Statistical leak current analysis creates a model for leak current fluctuation of devices in the circuit. A fluctuation distribution of leak current over the entire circuit is calculated as the sum of fluctuation of leak current from each device in the circuit. As a prior art reference, refer to Japanese Laid-Open Patent Publication No. 2009-164241.
However, according to the conventional technique, a huge number of devices (for example, tens of millions to hundreds of millions devices) are calculated to yield the sum of fluctuation of leak current as a fluctuation distribution of leak current over the entire circuit. Consequently, the processing time for the statistical leak current analysis has increased and the designing period has been lengthened.
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