Abstract: An aspect of the present invention is a method for laying out a power wiring of a semiconductor device. The method includes: modeling the power wiring as an analysis model including a plurality of nodes and a plurality of element resistors provided between the plurality of nodes neighboring each other; obtaining voltage values of the plurality of nodes by a circuit simulation; searching a path of a current flowing into a node of the plurality of nodes when an IR drop violation exists in the voltage values, the node having a maximum value of the IR drop violation; selecting a bottleneck element resistor from among the plurality of element resistors included in the path; and changing a resistance value of the bottleneck element resistor.

Abstract: A method for laying out a power wiring of a semiconductor device including an analog circuit and a digital circuit includes: modeling the power wiring as an analysis model including a plurality of nodes and a plurality of element resistors provided between the plurality of nodes neighboring each other; obtaining voltage values of the plurality of nodes by a circuit simulation; searching a maximum current node from nodes of the digital circuit when a substrate noise violation exists in a voltage value of a node of the analog circuit, the maximum current node having a maximum amount of current flowing into the node of the analog circuit; searching a path of a current flowing into the maximum current node in the digital circuit; selecting a bottleneck element resistor from among the plurality of element resistors included in the path; and changing a resistance value of the bottleneck element resistor.

Abstract: A method for laying out a power wiring of a semiconductor device including an analog circuit and a digital circuit includes: modeling the power wiring as an analysis model including a plurality of nodes and a plurality of element resistors provided between the plurality of nodes neighboring each other; obtaining voltage values of the plurality of nodes by a circuit simulation; searching a maximum current node from nodes of the digital circuit when a substrate noise violation exists in a voltage value of a node of the analog circuit, the maximum current node having a maximum amount of current flowing into the node of the analog circuit; searching a path of a current flowing into the maximum current node in the digital circuit; selecting a bottleneck element resistor from among the plurality of element resistors included in the path; and changing a resistance value of the bottleneck element resistor.

Abstract: An aspect of the present invention is a method for laying out a power wiring of a semiconductor device.

Abstract: A flip flop circuit for a scan test comprises a first latch circuit for latching and outputting data signal D in synchronization with control signal CLK when control signal SC1 is set at one level and latching and outputting scan in data signal SIN in synchronization with control signal SC1 when control signal CLK is set at the other level, and a second latch circuit for latching and outputting an output of the first latch circuit in synchronization with control signal CLK when control signal SC2 is set at one level and latching and outputting an output of the first latch circuit in synchronization with control signal SC2 when control signal CLK is set at the other level. In this way, the area of the circuit is decreased by commonly using one latch circuit for a data signal and a scan in data signal. Also, the skew adjustment is not required during a scan test by operating with two-phase clocks during both scan shift operation and scan normal operation.