Mechanism Of The Fluoroscopic Measurement Of Sub-Surface Structure Using High Energy Scanning Electron Microscope

High energy scanning electron microscopy (SEM) has a potential to make a fluoroscopic measurement of the sub-surface structure of a specimen. When the energy is as high as 200keV, the three-dimensional structure of a hole of the order of lμm at a resist polymer surface can be measured quite accurately.[l] Because of this advantage, high energy SIEM is regarded as a powerful tool for inspection and measurement of the internal structure of LSIs without cleaving the chip for observing the cross-section. However, the phenomenon above mentioned has not been quantitatively explained. In order to know the suitable condition for this application, it is necessary to understand the mechanism how such phenomenon occurs. In the present work, we perform a Monte Carlo simulation of electron trajectory in the specimen, and discuss quantitatively the mechanism underlying the phenomenon.[2] The characteristic variation found in the experimental results are explained by the present simulation.