Laser Scattering: a Fast, Sensitive, In-Line Technique for Advanced Process Development and Monitoring

Laser scattering on unpatterned wafers is a common technique, mainly used in semiconductor fabs for optical wafer inspection (i.e. defectivity). Previously, the low frequency part of the scattered light (called “haze”) was viewed mainly as a noise source that limits the particle detection sensitivity. However, the haze signal of KLA Tencor SP1 and SP2 tools contains enough information to improve in‐line surface characterization and to give, in less than one minute for a full‐wafer mapping, very encouraging results when running large metal contamination studies or when developing and monitoring, for example, SGOI, GeOI and silicides processes.