Nano-Raman: Monitoring Nanoscale Stress.

Due to the new challenges accompanying every new shrink node in semiconductor industry new materials have to be implemented or device design has to be adapted—both to realize the intended device that still obeys physical laws. Visualization of these problems is a task of metrologists facing themselves physical borders. Monitoring stress becomes a major challenge arising from new processes applied as well as from worse surface to bulk volume-ratio or intended implied stress in new concepts of devices. High k-materials might induce macroscopic stress, which can be monitored on the wafer scale in wafer bow experiments. This unintended stress is even higher in patterned areas but not known in a micrometer scale. The knowledge of microscopic stress—or even nanoscopic stress—is even more important on intended stress implemented in devices and thus target of interest. This paper offers two ways of monitoring sub-micrometer stress. One is the well established scanning Micro-Raman technique. The second is a relatively new method called Tip-Enhanced-Raman-Spectroscopy (TERS). Both methods have their advantages but also challenges. The results of the easy to use scanning Micro-Raman technique need to be interpreted and information needs to be unfolded. Whereas the challenge of Tip-Enhanced-Raman-Spectroscopy lies in the experimental skills: handling a scanning-probe-microscope-tip in a Micro-Raman beam with the perspective of having a resolution restricted only by the SPM-diameter or even smaller. [ABSTRACT FROM AUTHOR]