ABSTRACT
Mechanical stress was an important concern in microelectronics between 1970, with the invention of the LOCal Oxidation of Silicon (LOCOS) isolation process [1], and the end of the 1990s. Local isolation processes were found to introduce stress in the surrounding silicon, which often lead to dislocations. This effect was initially mainly studied using finite element simulations. After the first publication by Kobayashi et al. [2] reporting the use of microRaman spectroscopy (mRS) to measure this stress, the amount of mRS papers on stress in microelectronics structures increased rapidly (Fig. 22.1). At that time, mRS was the only technique offering spatial resolution at the micron scale, which explains its popularity for this application. Toward the end of the 1990s, however, isolation structures and transistor devices became smaller than the resolution limits of the mRS technique and its application in this domain decreased. These limitations were only later partially overcome by the invention of surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS), etc. (see Chapter 6). Nevertheless, after 2000, the yearly number of publications on the use of mRS for stress measurements in microelectronics increased again drastically, as can be seen in Fig. 22.1. The reason for this is the birth of 3D technology.
