Cross-Sectional TEM Sample Preparation for Multilayer Electronic Materials

Abstract

ABSTRACTThe preparation of cross-sectional TEM samples from multilayer materials commonly encountered in electronic industry is difficult in general due to the large variation in chemical and physical etching rate. We have developed a technique consisting of a median incidence angle ion sputtering to perforation followed by a short time (<2 hours) low incidence angle sputtering with the glue line direction shielded from the ion beams. This technique takes advantage of the fast sputtering rate associated with the median incidence angle sputtering initially. The near normal (relative to the glue line direction) low angle sputtering in the second step smooths out any non-uniformity in thickness due to the strong dependence of sputtering rate on the sputtering angle. High quality TEM samples prepared from many different types of multilayer structures using this technique are demonstrated.