Failure Analysis and the Scanning Optical Microscope

The power of scanning optical microscopes (SOMs) lies in their ability to direct a small spot of light into an IC, producing photocarriers and heat in a localized area of the circuit. Photonic and thermal energy affect the I-V characteristics of the circuit in different ways, depending on the presence of defects and local material properties. This article explains how light beams interact with semiconductors and metals and how they influence the I-V characteristic of circuits and devices. It describes the basic physics of SOM measurements, provides examples of static and dynamic SOM techniques, and discusses emerging applications.