Patent ID: 8448125
Filing Date: 2013-05-21
Classification: G06F

Abstract:
1. A method of checking a current density limitation comprising: calculating a first allowable current value that becomes an allowable current value of a power supply wiring; extracting a number of vias connected to the power supply wiring; calculating a second allowable current value that becomes the allowable current value on a connected field side between the power supply wiring and the vias connected to the power supply wiring, the second allowable current value depending on the number of vias and a width of the power supply wiring; selecting a minimum allowable current value of the first allowable current value and the second allowable current value; checking by using a computer, the current density limitation based on a result of the selection; extracting the number of vias connected to the power supply wiring in an upper layer of the power supply wiring layer and the number of vias connected to the power supply wiring in a lower layer of the power supply wiring layer as the number of vias in the extracting; calculating a third allowable current value that becomes the allowable current value of the connected field side between the power supply wiring and the vias in the upper layer, and a fourth allowable current value that becomes the allowable current value of the connected field side between the power supply wiring and the vias in the lower layer as the second allowable current value in the calculating, the third allowable current value depending on the number of vias in the upper layer and the width of the power supply wiring, the fourth allowable current value depending on the number of vias in the lower layer and the width of the power supply wiring; and comparing the first allowable current value, the third allowable current value and the fourth allowable current value.