Depth dependence of UV curing of organosilicate low-k thin films

Ultraviolet (UV) radiation curing has emerged as a promising post deposition curing treatment to remove the porogen and promote structural rearrangements in organosilicate thin-film dielectric glasses for the use as next generation interlayer dielectrics. This study demonstrates that UV curing can result in significant depth dependence of the cure. Oscillating elastic modulus through the film thickness was observed by force modulated atomic forced microscopy (FM-AFM). We present a new standing wave model that accurately predicts the resulting depth dependent stiffness variations and can further be used to account for film absorption and shrinkage.