The field of CD-related metrology for process control went through a decade of rapid change. New metrology applications for direct estimation, monitoring, and control of key process parameters, such as effective exposure dose and focus in lithography, have emerged. They have enabled optical microlithography extensions to the diffraction limit for the smallest resolvable pitch and even beyond (with pattern multiplication). The arguments for direct metrology of dose and focus for better CD control are now over. What used to be the “off the roadmap metrology” is now a part of ITRS.