For sample preparation, e.g. cross-sectioning and thinning, SEM and TEM microscopists routinely use mechanical techniques (e.g., cleaving, slicing, lapping, polishing, and microtoming) and chemical or broad beam ion thinning. Two problems they run into are (1) locating the site of and crosssectioning or thinning at the site of extremely small features at specific locations (site specific samples) and (2) dealing with materials and material systems that are altered or destroyed by mechanical sample preparation (material-specific samples). These material systems may contain multiple components with dramatically different characteristics, such as hardness or chemical reactivity.

Many of these limitations can be overcome by using focused ion beam (FIB) micromachining, often referred to as “FIB microsurgery.” This technique can locate micron and submicron features and use precisely placed cuts to cross section and thin samples.