The interactions between magnetron-sputtered Cu and plasma-enhancedchemical-vapour-deposited a-SiCOF film have been investigated via x-rayphotoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) andscanning electron microscopy (SEM). High-resolution C 1s, Cu 2p, O 1s, Si 2pand F 1s XPS spectra for the samples before and after annealing are collected.The results show that the C-Cu bond is not observed at the interface ofCu/a-SiCOF before or after the annealing. Moreover, the annealing causes theobvious shifts of Cu 2p3/2, C 1s, O 1s and Si 2p photoelectronpeaks toward higher binding energy, and the underlying reasons are discussedin detail. The AES spectra of Cu L3M4,5M4,5 withthe etching time reveal that some chemical reactions take place at theinterface during the sputtering deposition of copper on the a-SiCOF film, andpossible reaction mechanisms are also presented. The Cu 2p3/2 XPSspectra and the SEM graphs demonstrate that the annealing enhances theinterdiffusion between Cu and a-SiCOF film.