Characterizing cross-sectional profile variations by using multiple parameters extracted from top-down SEM images

This paper describes a new approach towards monitoring the semiconductor lithography process using critical dimension scanning electron microscopy (CD-SEM). In the lithography process, there are two important process parameters, exposure dose E and focus F. To monitor both the E and F variation, a new method for characterizing the cross-sectional profile of the photoresist pattern from the secondary electron (SE) waveform has been developed. An innovative feature of this method is that it can quantify the degree of top rounding (TR) and bottom rounding (BR) of the cross-sectional profile separately.