<title>Investigation of stress/strain of silicon on insulator using optical second harmonic generation method</title>

Abstract

Optical second harmonic generation (SHG) method has been applied to the investigation of mechanical stress condition of BESOI (bonded and etched-back silicon on insulator) wafers. SHG scanning of SOI wafers show drastic variations, which are explained, in the case of thin film BESOI, by the mechanical stress arising from the bonding of rough surfaces, and, in the case of thick film BESOI wafer, by the presence of polish-induced strain that results from the thinning process of the wafer. SHG rotational dependence was observed for BESOI wafers, and its symmetry preservation indicates essentially sound silicon film quality despite a high level of mechanical stress. Mechanical stress effect on the SHG signal is also demonstrated through externally applied stress on the BESOI wafer. SHG method is shown to be able to characterize mechanical stress of BESOI wafers and may even identify the sources of the stress.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.