Published online by Cambridge University Press: 01 February 2011
In this paper, we investigated the role of ultra-violet light (UV) curing on the molecular structure and fracture properties of a porous organosilicate glass (OSG) dielectric with k∼2.5. A correlation between material properties, including fracture toughness, and molecular structure was found. Multiple analytical techniques including Fourier Transform IR (FTIR) Spectroscopy, x-ray photo-emission spectroscopy (XPS) and x-ray reflectivity were used to investigate changes in the molecular bonding and material properties with UV curing. Overall, UV seems to be highly penetrating leading to uniform composition and density changes in the low k film to improve its properties. The decrease of methyl and hydrogen content relative to the Si-O-Si bonding structures led to increasing density and dielectric constant with UV exposure. UV curing increases the critical fracture toughness, while the sub-critical fracture toughness is insensitive to UV cure. The correlation between critical fracture toughness and material properties is discussed.