Characterising circuit cell performance variability in response to pertibations in manufacturing process parameters

A computer readable library of circuit cells comprising:

• one or more designs files specifying circuit cell designs;
• one or more performance parameter variation files specifying for each circuit cell a variation in a performance parameter associated with a joint amount of perturbation in manufacturing process parameters of said circuit cell;
• and
• a correlation file specifying a correlation value between manufacturing process parameters of different families of circuit cells, each family sharing a substantially common set of perturbations in manufacturing process parameters that produce corresponding predetermined amounts of change in said performance parameter of a circuit cell away from an unperturbed value of said performance parameter.

A computer program product for controlling a computer to perform computer aided integrated circuit library design operations using a library of circuit cells comprising:

• one or more designs files specifying circuit cell designs;
• one or more performance parameter variation files specifying for each circuit cell a variation in a performance parameter associated with a joint amount of perturbation in manufacturing process parameters of said circuit cell;
• and
• a correlation file specifying a correlation value between manufacturing process parameters of different families of circuit cells, each family sharing a substantially common set of perturbations in manufacturing process parameters that produce corresponding predetermined amounts of change in said performance parameter of a circuit cell away from an unperturbed value of said performance parameter.