Laser spike anneal macro & micro non-uniformity investigation using modulated optical reflectance and four-point-probe

Laser spike anneal (LSA) is one of major millisecond anneal techniques for forming ultra-shallow and highly activated junctions. With its ultra-fast heating capability, LSA has found a range of applications in ultra-shallow junction (USJ) applications. However, there are some challenges associated with the technique that need to be effectively addressed to ensure the quality of LSA processes. One of such challenges is macro and micro non-uniformity resulted from LSA process. In this work, the non-uniformity was studied using modulated optical reflectance (MOR) and sheet resistance measurement by four point probe. Significant macro and micro non-uniformity was observed through these metrologies. The impact of LSA process knobs, such as scanning method, overlap percentage and rotation on non-uniformity was investigated.