| 摘要 |
PURPOSE:To detect the SN ratio of a mask flaw signal after improving the same without increasing an electron beam detecting time, by scanning a mask by electron beam and simultaneously detecting a plurality of secondary electron signals and one transmitted electron signal to apply operational processing to the detected signals. CONSTITUTION:The X-ray mask on a specimen stage 5 is irradiated with electron beam from an electron beam irradiator 1. The pattern part of the X-ray mask 4 comprises a membrane with a thickness of about 1-2mum and electron beam is reflected by the pattern edge or transmitted therethrough. Two left and right secondary electron detectors 2 are provided on the specimen stage 5 to detect secondary electron signals which are, in turn, sent to secondary electron signal processing parts 6 to be subjected to amplification and wave-form shaping at every left and right edges. Further, simultaneously with the detection of the secondary electron signals, the electron beam transmitting through the pattern edge is detected by a transmitted electron detector 3 to be sent to a transmitted electron signal processing part 7 and subjected to amplification and wave-form shaping. The secondary electron signals and the transmitted electron signal are added by an operational processing part 8 to detect a pattern flaw signal. Therefore, the flaw of the mask can be certainly detected because the secondary electron signals and the transmitted electron signal are subjected to operational processing. |
