A method is disclosed including: generating, based on design information for an integrated circuit, a circuit design that includes an initial power delivery network (PDN) for the integrated circuit; performing a pre-layout simulation to the circuit design that includes the initial power delivery network, to determine whether the circuit design meets a predetermined specification; generating a circuit layout of the integrated circuit when the circuit design meets the predetermined specification; and adding at least one additional conductive pillar or at least one additional power rail in the initial power delivery network according to a relationship of a pillar density of the initial power delivery network and a maximum pillar density when the circuit design does not meet the predetermined specification.