Nondestructive Internal Observation of MOS-LSI Designed by 0.8μm Rule as a Specimen Using Electron-Acoustic Microscopy

摘要

Nondestructive internal observation of a MOS (metal-oxide-semiconductor) LSI chip designed by 0.8μm rule was carried out by electron-acoustic microscopy (EAM). The LSI chip as a specimen was uncovered and the passivated film on the chip was etched off by a dry etching method, keeping the chip mounted on a ceramic package (50×50×5mm3). The EA signal generated by irradiation of a chopped electron beam was picked up by a PZT detector attached, interposed by the package, to the back of the LSI chip specimen and was amplified using a lock-in amplifier. Thus sample prerpared can be measured SEM mode images, EAM mode images and electrical properties of the device, nondestructively. The results were under: (A) The EBIC (electron beam induced current) images and the SEM images are not the same from images of one flame scan, (B) new findings of internal structure of the chip are obtained from the both images. (C) The observable depth (tx) was proportionally related to the electron range (Re).