US Patent 7199472 Semiconductor device

In a semiconductor device having the upmost wiring layer comprised of aluminum and the wiring layer immediately below it comprised of copper, the upmost wiring layer is made thicker than the wiring layer immediately below it so that the upmost wiring layer is lower in sheet resistance than the wiring layer immediately below it. Multiple ring power lines VR and pads PD are formed of the upmost wiring layer, and the ring power lines VR and the pads PD are connected respectively through power lines VLB1 of the upmost wiring layer. Consequently, the voltage drop on the power feed path from the pads PD to the ring power lines VR can be reduced and the power conduction from the pads PD to the ring power lines VR can be stabilized.