Hybrid CD metrology concept compatible with high-volume manufacturing

Abstract

The measurement uncertainty is becoming one of the major components that have to be controlled in order to guarantee sufficient production yield. Already at the R&D level, we have to cope up with the accurate measurements of sub-40nm dense trenches and contact holes coming from 193 immersion lithography or E-Beam lithography. Current production CD metrology techniques such as CD-SEM and OCD are limited in relative accuracy for various reasons (i.e electron proximity effect, outputs parameters correlation, stack influence, electron interaction with materials...). Therefore, time for R&D is increasing, process windows degrade and finally production yield can decrease because you can not manufactured correctly if you are unable to measure correctly. A new high volume manufacturing (HVM) CD metrology solution has to be found in order to improve the relative accuracy of production environment otherwise current CD Metrology solution will very soon get out of steam. In this paper, we will present a potential Hybrid CD metrology solution that smartly tuned 3D-AFM and CD-SEM data in order to add accuracy both in R&D and production. The final goal for chip makers is to improve yield and save R&D and production costs through real-time feedback loop implement on CD metrology routines. Such solution can be implemented and extended to any kind of CD metrology solution. In a 2nd part we will discuss and present results regarding a new AFM3D probes breakthrough with the introduction of full carbon tips made will E-Beam Deposition process. The goal is to overcome the current limitations of conventional flared silicon tips which are definitely not suitable for sub-32nm nodes production.