The Scanning Confocal Electron Microscope: A New Tool for Defect Studies in Semiconductor Devices

Abstract

This work illustrates succinctly the ability of the SCEM to provide valuable information for metrological studies of thick non-optically transparent semiconductor devices. The utility of SCEM to failure analysis comes from its ability to provide relatively high-resolution images from extremely thick specimens. In this way, the instrument can bridge the gap between optical SCOM useful for observing features few microns in size, to TEM which can resolve atomic sized structures but requiring specimens less than 100 nm thick to reach this resolution. The main advantage of SCEM for failure analysis in semiconductor manufacturing is to investigate defects or devices without the need to significantly de-capsulate or cross-section to thickness typically employed by TEM/STEM observations. This allows un-disturbed observation of embedded defects. Depth of field and focus of the SCEM, like the SCOM are limited by the pre and post specimen convergence angles. With the advent of aberration correctors this aspect of the SCEM will become an even more useful tool