Semiconductor structure

A semiconductor structure includes a semiconductor substrate and a macro cell. The macro cell includes a clock input terminal, a first and a second D flip-flop standard cells. The clock input terminal receives a clock signal. The first D flip-flop standard cell has a first clock terminal coupled to the clock input terminal, a data input terminal, and a data output terminal. The second D flip-flop standard cell has a first clock terminal coupled to clock input terminal, a data input terminal, and a data output terminal. The first and the second D flip-flop standard cells both have a rectangular layout with two long edges and two short edges. The first and the second D flip-flop standard cells are adjacent to each other by a long edge of the first D flip-flip standard cell and a long edge of the second D flip-flop standard cell.