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NIST/SEMATECH Collaboration: Application of Nano-Tips to Production CD-SEMs

Published

Author(s)

Andras Vladar, Michael T. Postek

Abstract

This work documents the first part of a two-part study about the application of nano-tips to critical dimension (CD) scanning electron microscopes used in integrated circuit production.  Nano-tips, by comparison to all conventional cold, thermally assisted and Schottky field emitters, offer a substantial increase in brightness and large reduction in source size.  This could provide a significant improvement in current CD-SEM technology and help to extend it beyond the 180-nm technology.  In an optimized electron optical column, the substitution of conventional field emitter electron source by a nano-tip is also expected to produce higher beam currents into a spot of given size.  This improvement is a consequence both of the increase in electron source brightness and because the smaller source size allows the use of a lower demagnification, resulting in a higher fraction of the gun emission reaching the final beam spot.  The work in the first part of this study included the preparation of a CD-SEM, the theoretical assessment of the gun and the electron optical column, the modifications needed for the new nano-tips and the design and implementation of a measuring system that allows for adequate measurements.  The results of the first of this portion of the study indicated that using a sharp-tip as an intermediate to the nano-tip an improvement in the performance of a CD-SEM can be clearly demonstrated.  This and the results of the theoretical assessement give support for the installation of the nano-tips and points to even better performance.
Citation
NIST/SEMATECH Collaboration LITG 410I Project Final Report

Keywords

critical dimension, field emission, nano-tips, scanning electron microscope, SEM Sentinel, sharp-tips

Citation

Vladar, A. and Postek, M. (2000), NIST/SEMATECH Collaboration: Application of Nano-Tips to Production CD-SEMs, NIST/SEMATECH Collaboration LITG 410I Project Final Report (Accessed June 8, 2023)
Created November 15, 2000, Updated February 19, 2017