Milling Process Control with Dimensional Feedback on a Focused Ion Beam - Scanning Electron Microscope System (FIB-SEM)

摘要

In nanofabrication and nanoanalysis, focused ion beam - scanning electron microscope (FIB-SEM) systems are used for patterning tasks which demand accurate dimensional control. Verifying and correcting for patterning accuracy during the FIB milling process in an automated fashion has previously not been possible. Here, a dedicated lithography platform on a commercially available FIB-SEM system controls the critical dimension during a FIB milling process. This is achieved by controlling FIB-SEM system's stage, the ion optics, and the electron optics through a single software interface. The pattern generator and software suite provides for independent alignments for each column, beam drift and stage offset corrections, dimensional metrology, and feedback. SEM-based metrology provides closed-loop feedback during the FIB milling process. In an automated fashion, SEM-based metrology feedback to the FIB milling process achieves a final size accuracy of better than 0.2%.