Application of statistical metrology to reduce total uncertainty in the CD-SEM measurement of across-chip linewidth variation

Statistical metrology can be defined as a set of procedures to remove systematic and random gauge error from confounded measurement data for the purpose of reducing total uncertainty. We have applied these procedures to the determination of across-chip linewidth variation, a critical statistic in determining the speed binning and average selling price of advanced microprocessors, digital signal processors, and high-performance memory devices. The measurement data was obtained from tow sources: a high- throughput CD-SEM and an atomic force microscope. We found that the high-throughput of SEM permitted the additional measurements required for statistical metrology and heterogeneous gauge matching.