US Patent 7443224 Multi-threshold MIS integrated circuit device and circuit design method thereof

On a chip 50A, disposed are macro cell 20A not including a virtual power supply line and a leak-current-shielding MOS transistor of a high threshold voltage, and a leak-current-shielding MOS transistor cell 51 of the high threshold voltage. The transistor cell 51 has a gate line 51G which is coincident with the longitudinal direction of the cell, is disposed along a side of a rectangular cell frame of the macro cell 20A, and has a drain region 51D connected to VDD pads 60 and 61 for external connection, the gate line 51G connected to an I/O cell 73 and a source region 51S connected to a VDD terminal of the macro cell 20A. This VDD terminal functions as a terminal of a virtual power supply line V_VDD.