Critical dimension measurement in the SEM: comparison of backscattered vs. secondary electron detection

摘要

Abstract: Critical dimension measurements for state of the art sub-micron semiconductor processes are typically accomplished using automated scanning electron microscopes. The measurements generated in these instruments are primarily based upon secondary electron imaging techniques. Several issues associated with this mode of SEM imaging that directly impact the precision and accuracy of the measurement system are reviewed. These issues have led to the current investigation of SEM metrology utilizing backscattered electron imaging techniques. The implications and differences between SE and BSE imaging techniques and their relation to CD measurements are discussed in this work. !17