Improving the speed of scanning electron microscope deflection systems
K W Lee; J T L Thong; K W Lee; Centre for Integrated Circuit Failure Analysis and Reliability, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore; J T L Thong; Centre for Integrated Circuit Failure Analysis and Reliability, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
Журнал:
Measurement Science and Technology
Дата:
1999-11-01
Аннотация:
A simple technique to characterize the response of a SEM deflection system is described. By measuring the delay in the SEM video signal as the primary beam is deflected and swept over a knife-edge, the transient deflection response can be mapped out. The transfer function of the beam deflection is then approximated by exponential functions and appropriate analogue filters are designed to pre-emphasise the deflection coil drive signal in order to increase the deflection speed. This technique is used to decrease the deflection response time from typically ~6 µs to ~0.5 µs, thereby allowing the implementation of non-raster scanning schemes that require fast point-to-point deflection.
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