The primary objectives of failure analysis on structurally complex semiconductor devices are often to determine a defect's location and composition. Determining exactly how these defects propagate through a sample in three dimensions, to confirm a failure mode, is often elusive. This paper discusses characterizations of two defect types to illustrate a technique of sequentially imaging whisker type defects from orthogonal orientations using TEM/STEM. The first type is a high resistance short between two metal lines that is best imaged using STEM in order to observe subtle differences in material composition. The second is a crystalline dislocation through an optoelectronic device that is best observed using TEM. Details of resistive short characterization and crystalline defect characterization performed are provided. TEM/STEM has shown to be a practical tool for locating defects prior to cross sectional analysis. This allows defects to be located and characterized in three dimensions.

Advances in semiconductor technology are driving the need for new metrology and failure analysis techniques. Failures due to missing, or misregistered implants are particularly difficult to resolve. Two-dimensional implant profiling techniques such as scanning capacitance microscopy (SCM) rely on polish preparation, which makes reliably targeting sub 0.25 um structures nearly impossible.[1] Focused ion beam (FIB) machining is routinely used to prepare site-specific cross-sections for electron microscopy inspection; however, FIB induced artifacts such as surface amorphization and Ga ion implantation render the surface incompatible with SCM (and selective etching techniques). This work describes a novel combination of FIB machining and polish preparation that allows for site-specific implant profiling using SCM.