The thermodesorption from SiO2/SiLK resin dielectric assemblies at various stages of interconnect fabrication are studied by mass spectrometry. Species desorption from such an assembly is governed by the intrinsic material properties and the process step history, such as patterning chemistry and by environmental contamination. The thermodesorption of an as-cured SiLK resin film is compared to the desorption of species after different process steps. It is shown that as cured SiLK films contain very low amounts of moisture and volatile organic compounds. The plasma-enhanced chemical vapor deposition SiO2 hardmask is the main source of moisture in the SiO2/SiLK resin dielectric stack. Annealing at T greater than or equal to 350 degrees C in both vacuum and nitrogen ambient conditions drastically reduces the species desorption. The origin and the kinetics of the desorbed species are described.