Investigation of Pattern Effects in Rapid Thermal Processing Technology: Modeling and Experimental Results

During rapid thermal processing, nonuniformity of local radiative properties in the wafer front side is now obviously identified to results in thermal dispersion at die scale. This leads to changes in annealing temperature and thus variabilities of electrical behavior and device performances. However, these detrimental contributors remain a hard job to manage. Indeed, both optical and thermal physics are involved, a wide range of scales plays role, and many modeling challenges must be faced to understand and solve such issues. In this study, absorptivity and emissivity of various periodic patterned structures are investigated by optical modeling. It is clearly demonstrated that diffraction plays an important role when gate width dimension or space between gates become small. Then, the radiative properties can be mapped at die scale and hence a thermal simulation can be performed. Our intra-die simulated thermal gradient is in good agreement with experimental results.