Fourier transform feedback tool for scanning electron microscopes used in semiconductor metrology

The utility of the sharpness concept for use on metrology scanning electron microscopes (SEM) as implemented through the Fourier transform technique has been clearly demonstrated and documented. The original methods for sharpness analysis were labor-intensive and therefore not suited to industrial applications like semiconductor integrated circuit production. We have integrated these techniques into an easy to use and stand alone software package called SEM monitor which makes the analysis easy and moreover can serve as a prototype for integration into a production tool This paper will present the general philosophy of the system and analytical data taken form both laboratory and production instruments to prove both the relevance of the sharpness concept and the usefulness of this tool for SEM performance monitoring.