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A confocal Raman microscopy technique is presented that allows stressmeasurement at the nanoscale, which in turn enables measurement of stressintensityfactors (SIF) at crack tips and thus toughness to be estimated. Peakfittingand high-resolution spatial stepping techniques enable stress resolution ofapproximately 20 MPa at measurement separations of approximately 100 nm.Micro- and nano-indentation and crack field stress distributions are measured andcompared with analytical expressions. The SIF for indentation cracks in Si isshown to be in the range 0.2 MPa m1/2 to 0.4 MPa m1/2, consistent with chippinginducedindentation stress relief and the toughness of Si.