Determination of stress in silicon wafers using Raman spectroscopy

With a strong industrial trend towards using thin silicon in semiconductor devices, process legacy-induced stresses are matter of increasing practical importance. A key problem here is a lack of suitable metrology equipment for measuring inherent substrate material stresses in the manufacturing line. To overcome this, the use of Raman microspectrometry as a tool for measuring stress levels and distributions quantitatively on entire productive wafers was researched. Combining model cases, theoretical considerations and real-world samples, it could be shown that Raman can provide the necessary analytical accuracy and reliability, allowing to relate ensuing stress states e.g. to different wafer thinning process parameters.