A new technique for the determination of secondary electron (SE) spectra of
insulators in a scanning electron microscope environment is presented. It
is based on a capacitatively coupled charge measurement by subjecting the i
nsulating film to a controlled pulsed electron beam. With the use of a plan
ar grid analyzer configuration, an algorithm is used to estimate the SE spe
ctrum based on normalized values of the S-curve obtained. Secondary electro
n spectra from several insulating materials employed in integrated circuit
manufacturing, including silicon nitride (Si3N4), AZ 1350J photoresist, and
pyralin polyimide, have been measured.