Precision and accuracy of CD-SEM profile reconstruction for the 110 technology node

Abstract

We use CD-SEM side-wall imaging on the Applied Materials NanoSEM 3D system as a destruction free and quick method to determine side-wall profiles. From two different tilt angles up to 15 degrees the reconstruction of side-wall profiles is possible in a quick and non destructive way even for negatively sloped profiles. We demonstrate precision and accuracy of height and side-wall angle determination on selected examples. Additionally we demonstrate the fully automatic determination of the spatial frequency of LER on samples containing artificial LER of different amplitudes and spatial frequencies. Finally, we use the beam tilt capability SEM to investigate 193 nm resist line edge roughness (LER) and the transfer of this LER into etch. We show how top and bottom LER can be separated from each other by measuring the same sample at different beam tilt angles. The demonstrated methods reduce cycle time significantly and saves wafers for time consuming X-SEM investigations.