Abstract
The challenging metrology application for scatterometry and CD-SEM is to accurately measure both CD and profile. To apply this metrology specifically to dual-damascene hole structures is critical for the back-end processing, in order to control both the CD and the process overall. This paper discusses applications of Optical Digital Profilometry-based scatterometry to the advanced 90nm node dual-damascene process. The application includes contact ADI, via AEI, via etch, and via fill. The results show that scatterometry can measure CD, as well as provide side wall angle and profile information that is unavailable by CD-SEM. Correlations to CD-SEM and cross-sectional SEM are also presented. For future applications, scatterometry is a viable solution for 3D structures, and provides higher precision, and more metrology information than current metrology methods for critical dual-damascene processes.