| 摘要 |
PURPOSE:To enhance the reproducibility of measurement by readjusting the focus of laser beam or electron beam when the waveform of a reflected signal or that of a secondary electron signal is unsimilar to the waveform of a reference signal to perform re-detection. CONSTITUTION:Prior to measurement, the waveform SA of a reference signal corresponding to a pattern edge is stored in a reference signal waveform memory means 1. At the time of measurement, laser beam is generated by a laser beam generating/scanning means 3 to be projected on an objective pattern and a reflected beam signal is detected by a detector 5 to obtain a reflected beam signal waveform SB which is, in turn, corrected by an amplitude correction means 6 so that the difference between the base line and peak value of the reflected beam signal waveform SB coincides with that of the reference signal waveform SA to obtain a signal SB. Then, the difference between the reference signal waveform SA and the waveform of the signal SB' is calculated according to a convolution method by a signal waveform comparing means 7 and, when the difference is larger than a prescribed value, the focus of the laser beam generating/scanning means 3 is adjusted through a focus matching mechanism 4 and the difference is set to a prescribed value before measurement. |
