Program procedures executed to rout a bus, via a processing unit, include a bus information extractor configured to extract bus information including physical requirements for the bus, from input data, a buffer array generator configured to generate a buffer array in which buffers included in the bus are regularly arranged based on the bus information, a buffer array placer configured to place at least one buffer array in the layout of the integrated circuit based on the bus information, and a wiring procedure configured to generate interconnections connected to buffers included in the at least one buffer array based on the bus information.