How much variability can designers tolerate?

Designers hate large variations in a gate's critical dimensions (CDs) because large variations imply large guardbanding in design. Lithographers hate small variations in CD numbers because they imply impossible process windows. With the publication of the 2003 International Technology Roadmap for Semiconductors (1TRS), gate CD control requirements for lithography and front-end (etching) processes will doubtless receive intense scrutiny.