Imaging deep holes in structures with gaseous secondary electron detection in the environmental scanning electron microscope

Abstract

The gaseous secondary electron detector (GSED) in the environmental scanning electron microscope (ESEM) permits collection of electron signals from deep inside blind holes in both conducting and insulating materials. The placement of the GSED as the final pressure-limiting aperture of the ESEM creates a situation of apparent illumination along the line of sight of the observer. In principle, any point struck by the primary beam can be imaged. Image quality depends on the depth of the hole. In brass, features at the bottom of a 1.5 mm diameter hole that was 8 mm deep were successfully imaged. © FAMS, Inc.