Patent ID: 7559041

Claim:
A method for designing a semiconductor integrated circuit using a cell library that stores standard cells used for designing the integrated circuit, wherein the standard cells include a flip flop function device having a data input terminal, a clock input terminal and first and second data output terminals, the flip flop function device including, a first latch having a data input connected to the data input terminal and a clock input connected to the clock input terminal by way of an inverter, and generating a first latch output signal, a second latch having a data input that receives the first latch output signal and a clock input connected to the clock input terminal, and generating a second latch output signal, and a third latch having a data input that receives the second latch output signal and a clock input connected to the clock input terminal by way of an inverter, and generating a third latch output signal, wherein the second latch output signal comprises the first data output terminal of the flip flop function device and the third latch output signal comprises the second data output terminal of the flip flop function device; the method comprising the steps of: designing a circuit by forming a data path with the standard cells, wherein interconnected flip flop function devices include a former device and a latter device wherein the first data output of the former device is connected to the data input terminal of the latter device and the second data output terminal of the former and latter devices are unconnected; inspecting the designed circuit for potential hold time violations in data paths of interconnected flip flop function devices therein; and correcting any detected potential hold time violations in said data paths by disconnecting the first data output terminal of the former device that is connected to the data input of the latter device, and connecting the second data output terminal of the former device to the data input terminal of the latter device.