A modulus mapping technique is described which provides quantitative information about the elastic properties of the near-surface region of both unpatterned and patterned silica-based low dielectric constant (low-k) thin films. The extent of oxygen plasma-induced damage has been studied using this method. Compared with quasi-static nanoindentation, the modulus mapping technique is more surface sensitive. This is first demonstrated for thin Ta layers on top of low-k films, where the effective modulus systematically increases with the Ta film thickness. Correspondingly, the effective modulus of the near-surface region of a plasma-treated low-k film is significantly higher than that measured on the same type of low-k film without treatment. Modulus mapping performed on integrated Cu/low-k structures showed that a sub-micrometer spatial resolution is clearly achievable. Furthermore, the effective modulus of patterned low-k material between inlaid copper interconnects was found to be considerably higher than the modulus measured on a blanked low-k film of the same type.