TEM Sample Preparation Using A Focused Ion Beam and A Probe Manipulator

Abstract

Cross-sectioning is a necessary technique for the failure analysis of integrated circuits. Historically, the majority of samples have been prepared for scanning electron microscope (SEM) analysis. Today's smaller geometry devices, however, increasingly require the improved spatial resolution afforded by the transmission electron microscope (TEM), both in imaging analysis and in elemental analysis. Specific-area cross-section TEM (SAXTEM) analysis allows the failure analyst to identify defects that may go undiscovered in the SEM. A procedure is described for a timely preparation of SAXTEM samples using a focused ion beam (FIB) instrument and a manipulator probe. This procedure extends the state-of-the-art in several key respects: A) no mechanical grinding is necessary, B) samples as large as the FIB chamber can be accommodated, e.g., whole wafers, C) multiple samples can be prepared from one die, D) the procedure is faster and more repeatable than previously reported procedures.