Enhancement of voltage contrast inspection signal using scan direction

In-line voltage contrast inspection has taken off in popularity in the last decade. While the impact of this technique has already been dramatic, the best known practices are still rapidly evolving. This paper shows that scan direction can have a very large influence on signal intensity for defects of interest and that flexibility to be able to scan in both the X and Y directions can prove very advantageous. Two examples are presented illustrating this point. The underlying physics behind this phenomenon are explained. A new best practice for voltage contrast inspection is then proposed.