Physical and chemical analysis of advanced interconnections using energy filtering transmission electron microscopy

Our newest method for interconnection analysis using focused ion beam (FIB) specimen thinning and energy filtering transmission electron microscopy (E FTEM) is presented. It is shown that using the site-specific capability and the controlled thinning effect of the FIB in addition with the high spatia l resolution of the EFTEM technique, fast chemical analysis of materials wi th nanometre spatial resolution can be obtained. This is the only method fo r the observation of very thin diffusion barriers and interfaces in the pre sence of drastic topography. Application examples are given concerning firs tly, the in-depth analysis of tungsten aluminum technology, barrier integri ty and interdiffusion of elements near interfaces and secondly, the surface contamination of copper in copper interconnection technology with high asp ect ratio contacts. In this case, photoresist spin-coating is carried out p rior to FIB thinning. This method is an alternative to surface analysis tec hniques and offers the best spatial resolution without topography Limitatio ns. (C) 2000 Elsevier Science B.V. All rights reserved.