Specimen Preparation for Semiconductor Analysis
Specimen preparation is absolutely the key for quantitative transmission electron microscopy (TEM) analysis; modern transmission electron microscopes are very powerful and stable and, generally speaking, the accuracy of the analysis is now mainly limited by the quality of the specimen. It is a lot easier to learn how to make a good sample, than to perform the complicated analysis that is required for non-perfect TEM lamella.
One of the key differences between specimen preparation for semiconductor research and other fields is that in nearly all cases, nanometer-scale site specificity is required. In addition, such specimens can be made up of many different types of materials in this nanoscaled volume. As a result, the focused ion beam (FIB) milling tool is now indispensible. The FIB is an extremely versatile tool that uses an ion beam, metal deposition, micromanipulators and secondary electron detectors for cutting, sticking, modifying, connecting and imaging materials with nm-scale accuracy and resolution. There already exist many excellent books that present the FIB in detail. Here, we will only discuss the background of how specimens can be made. The FIB uses a beam of ions to remove material and then thin an electron transparent region of interest directly from a wafer to allow characterization in the TEM. In this chapter, we will briefly discuss the operation of the FIB, then ion beam–sample interactions and specimen ...