A method of designing a circuit includes designing a first layout of the circuit based on a first plurality of corner variation values for an electrical characteristic of a corresponding plurality of back end of line (BEOL) features of the circuit. Based on the layout, a processor calculates a first delay attributable to the plurality of BEOL features and a second delay attributable to a plurality of front end of line (FEOL) devices of the circuit. If the first delay is greater than the second delay, a second layout of the circuit is designed based on a second plurality of corner variation values for the electrical characteristic of the corresponding plurality of BEOL features. Each corner variation value of the first plurality of corner variation values is obtained by multiplying a corresponding corner variation value of the second plurality of corner variation values by a corresponding scaling factor.