Patent ID: 7007257

Claim:
An automatic placement and routing apparatus used for layout design of a semiconductor integrated circuit including a plurality of power supply systems with different potentials, said automatic placement and routing apparatus comprising: a cell library for storing cells; and a layout design section for carrying out the layout design of the semiconductor integrated circuit using the cells stored in said cell library, according to a netlist describing logic connection information about the semiconductor integrated circuit and timing constraint information about the semiconductor integrated circuit, wherein said layout design section comprises: a link section for linking the netlist to the cells stored in said cell library; an initial power supply setting section for setting initial power supply potentials of the cells linked with the netlist; a placement and routing section for carrying out placement, global routing and detail routing of the cells stored in said cell library according to the netlist and the timing constraint information; a timing verification section for carrying out timing verification of specified paths at a specified stage of the placement and routing by said placement and routing section according to layout information; and a power supply modification section for specifying, when the timing verification section detects a cell having a timing problem, change of the power supply potential of the cell, and wherein when the timing verification section detects the cell having a timing problem, according to the change of the power supply potential of the cell specified by said power supply modification section, said placement and routing section carries out replacement and rerouting of the cell in accordance with the change of power supply potential specified by said power supply modification section and optimizes the layout, and said timing verification section carries out the timing verification of the specified paths according to the optimized layout information.