SEM-Based Characterization Techniques

Abstract

The scanning electron microscope is now a common instrument in materials characterization laboratories. The basic role of the SEM as a topographic imaging system has steadily been expanding to include a wide variety of SEM-based analytical techniques. These techniques cover the range of basic semiconductor materials characterization to live-time device characterization of operating LSI or VLSI devices. This paper will introduce many of the more commonly used techniques, describe the modifications or additions to a conventional SEM required to utilize the techniques, and give examples of the use of such techniques. First, the types of signals available from a sample being irradiated by an electron beam will be reviewed. Then, where applicable, the type of spectroscopy or microscopy which has evolved to utilize the various signal types will be described. This will be followed by specific examples of the use of such techniques to solve problems related to semiconductor technology. Techniques to be emphasized will include: x-ray fluorescence spectroscopy, electron beam induced current (EBIC), stroboscopic voltage analysis, cathodoluminescence and electron beam IC metrology. Current and future trends of some of these techniques, as related to the semiconductor industry, will be discussed.