A system includes a library, a processor and an output interface. The library contains at least one leakage lookup table related to leakage current values for different cell abutment cases of abutted cells in a semiconductor device. The cell abutment cases are associated with terminal types of cell edges of the abutted cells. The processor is configured to perform an analysis to detect boundaries between the abutted cells, identify attributes associated with the terminal types of the cell edges, identify the cell abutment cases based on the attributes, and calculate maximal boundary leakages between the abutted cells based on leakage current values associated with the cell abutment cases and leakage probabilities associated with the cell abutment cases. The output interface is for outputting boundary leakages corresponding to the maximal boundary leakages in the semiconductor device. A method is also disclosed herein.