Low voltage SEM, Auger, and XPS of surface contaminants

Abstract

Scanning electron microscopy has been successfully applied in nearly all fields of scientific endeavor. In most cases, the desired information was obtained operating the SEM with beam energies ranging from 10-30 KeV. Recently, with the advent of SEMs specially designed for operation at low beam energies, it became practical to perform analysis with low beam energies. In the field of semiconductors, to avoid charging the surface by the incident beam, the use of selected low beam energies became mandatory for circuit testing and photoresist line width measurements. In the field of materials analysis, occasional use of low electron beam energies was made, in which surface details were highlighted. With lower beam energies, the penetration of the electron beam is reduced and the interaction of the beam with surface features becomes more pronounced. In the past, widespread utilization of this mode of scanning electron microscopy was not practical because most SEMs had a severely reduced spatial resolution at beam energies of less than 5 KeV.