A selected area planar TEM (SAPTEM) sample preparation technique for failure analysis of integrated circuits using a transmission electron microscope has been developed. The technique employs a combination of mechanical grinding, selective wet/dry chemical etching (if required) and a two steps focused ion beam (FIB) milling. The mechanical grinding steps include: (a) a backside grind to achieve a die thickness less than 30μm, (b) the support half ring glue, and (c) a cross-section grind from one side to reach less than 35μm to the failing site. A selective wet or dry chemical etch is applied before, between, or after FIB thinning depending on the nature of problem and device components. The FIB milling steps involve: (a) a high ion current cross-sectional cut to reach as close as 5-8μm to the area of interest (b) a final planar thinning with the ion beam parallel to the surface of the die.
展开▼
