Raman micro-spectroscopy as a non-destructive key analysis tool in current power semiconductor manufacturing
There is a strong commercial incentive for characterizing power semiconductor devices during manufacture non-destructively. One area of concern are the stresses in the material introduced during manufacture by processes such as wafer thinning and chip separation. Raman spectroscopy can be used to measure stress in different semiconductor materials directly, non-destructively and quantitatively. Here, we describe Raman measurements on two semiconductor materials: silicon and silicon carbide. Measurements of silicon carbide are made on silicon carbide wafers; stress and material analyses of silicon are performed on: (i.) silicon wafers that had undergone different wafer thinning methods and (ii) along die sidewalls formed by mechanical and laser dicing. Our measurements demonstrate that micro-Raman spectroscopy is a feasible method for both measuring stress in thin wafers and for optimizing the thin wafer processes.