NIST/SEMATECH Collaboration: Application of Nano-Tips to Production CD-SEMs
Andras Vladar, Michael T. Postek
This is the final report of a two-part study about the application of nano-tips to critical dimension (CD) scanning electron microscope (SEMs) used in integrated circuit production. Nano-tips are essentially very sharp electron emitter tips that offer an increase in brightness of the electron source and a reduction in its size thus resulting in the potential for higher resolution. This could provide a considerable advantage over the current CD-SEM electron gun technology and could help to extend the use of CD-SEMs way beyond the 100 n device generation. The following was accomplished: modeling and theoretical calculation of the electron gun performance for regular and nano-tips, preparation of the SEM including the design and assembly of a measuring system for critical instrument parameters design and modification of the electron gun control electronics, development of a procedure for tip exchange, and preliminary tests of regular emitter, sharp emitter and a nanotip emitter. Using a sharp-tip as an intermediate to the nano-tip clearly demonstrated a improvement in the performance of the test CD-SEM. This and the results of the theoretical assessment gave support for the installation of the nano-tips and pointed to even better potential performance. Until the closing date of the current project, only one nano-tip was delivered. This nano-tip was tested but unfortunately did not exhibit nano-tip behavior therefore, nano-tip performance assessment could not be done by the closing date of this report. Work is still being done to generate the appropriately structured nano-tip and once one is available it will be tested. This document summarizes the current state of the work and points to possibilities that will open in the future when correct nano-tip assemblies are available.
NIST/SEMATECH Collaboration LITG 410I Project Final Report
field emission gun, nano-tip, scanning electron microscope, SEM tip preparation