The National Institute of Standards and Technology (NIST) is developing a specialized, metrology scanning electron microscope (SEM), having a metrology sample stage measured by a 38 picometer resolution, high-bandwidth laser interferometer system. The purpose of the NIST Reference Metrology SEM system is to carry out traceable calibrations of pitch and line width on standard reference samples using nanometer-level positioning of the sample under the electron beam in the SEM. Using the laser interferometer, with displacement measurements traceable to the International System of Units (SI), the X-Y sample-stage position is measured with a bandwidth of nearly 3 MHz while recording the secondary or backscattered electron output signal. This high-bandwidth measurement capability also becomes a tool to measure and compensate for the effects of environmental impacts on SEM measurements that evidence themselves as vibration and drift. This paper presents the metrology data acquisition and control system design, calibration methods. In addition this paper will show results obtained with the NIST Reference Metrology SEM.
Proceedings of euspen's 15th International Conference
June 1-5, 2015
euspen's 15th International Conference
SEM, X-Y stage, laser interferometer, nanometer measurement