Review Of CD Measurement And Scatterometry

Scanning Electronic Microscopes (SEM) are widely used either for cross‐section measurement (process development) or for top‐down CD measurement (production). ITRS roadmap for CD and overlay metrology points out some difficult challenges for next technology nodes. Up to now, we remained confident respectively in SEM capability and in bright field microscopy for next node requirements. Today, the limit of 0.1 micron is crossed and new requirements are stated for new 300 mm fabs. Demands arise for tighter precision, complex profile metrology and fully non‐destructive control for in‐line and integrated tools. Scatterometry is an alternative solution for CD and overlay metrology, recently introduced in fabs. We propose to review the capability of scatterometry actually demonstrated in fab and potential extensions targeting 65nm technology node. The use of optical CD tools in a production environment has also been assessed for various applications. Finally, an overview of capability extension will be given.