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Nondestructive Internal Observation in Electron-Acoustic Microscopy Using Metal-Oxide-Semiconductor LSI Chip

A metal-oxide-semiconductor (MOS)-LSI was observed by electron-acoustic microscopy (EAM) under various operating conditions of acceleration voltage (HV). The results are as follows. (1) When HV=20 kV, arrays of contact holes which were covered with both an Al (thickness: 0.5 µm) and an SiO2 ( 0.6 µm) layer could be observed. (2) However they could not be observed when HV=15 kV. (3) The observable depth of EAM is controllable using HV as a parameter. (4) The adjustment of the irradiation power of the electron beam should make it possible to achieve nondestructive internal observation of MOS-LSI specimens.