A method of modifying a cell includes determining a number of pins in a maximum overlapped pin group region. The method further includes determining a number of routing tracks within a span region of the maximum overlapped pin group region. The method further includes comparing the number of pins and the number of routing tracks within the span region to determine a global tolerance of the cell. The method further includes increasing a length of at least one pin of the maximum overlapped pin group in response to the global tolerance failing to satisfy a predetermined threshold.