Pyrometry for laser annealing

Laser annealing is one of the process solutions to enable ultra shallow junction (USJ) formation for the 45 nm technology node. However, variations in the front-side optical properties of device wafers cause large temperature variations on the wafer surface which, in turn, cause large variations in activation of the dopants that form the junction. As a result, pyrometry and closed loop temperature control are critical to establish process uniformity and repeatability for laser annealing. Pyrometry results are presented along with the correlation between the process results (dopant activation) and the pyrometer signal. Closed loop control and future technical challenges are discussed