Metrology Tools' Viability at 32 nm and Beyond (Part Ⅰ)

摘要

At 32 nm and beyond, efficient CD metrology technology must be selected by process equipment suppliers and de-vice makers. Over the course of three years, Intel (Santa Clara, Calif.) fabricated a variety of test structures to do technology evaluations to determine the limits of CD metrology. The purpose was to determine whether CD-SEM, scat-terometry, AFM, dual-beam, and high-voltage SEM could measure structures representative of the 45, 32 and 22 nm nodes. The research focused on 32 node features, and was partly prompted by the possibility that CD-SEM would, at some point, become limited. CD-SEM OEMs' initial results using the test structures were unsatisfactory — nobody presented acceptable results. Twelve months later, the OEMs had developed advanced processing algorithms and techniques that involved alterations to either the beam or column.