MICRO-RAMAN SPECTROSCOPY TO STUDY LOCAL MECHANICAL-STRESS IN SILICON INTEGRATED-CIRCUITS

Local mechanical stress is currently an important topic of concern in microelectronics processing. A technique that has become increasingly popular for local mechanical stress measurements is micro-Raman spectr oscopy. In this paper, the theoretical background of Raman spectroscop y, with special attention to its sensitivity for mechanical stress, is discussed, and practical information is given for the application of this technique to stress measurements in silicon integrated circuits. An overview is given of some important applications of the technique, illustrated with examples from the literature: the first studies of th e influence of external stress on the Si Raman modes are reviewed; the application of this technique to measure stress in silicon-on-insulat or films is discussed; results of measurements of local stress in isol ation structures and trenches are reviewed; and the use of micro-Raman spectroscopy to obtain more information on stress in metals, by measu ring the stress in the surrounding Si substrate is explained.