A low-k dielectric barrier, based upon silicon oxycarbide, was developed for Cu damascene processes. Optimum process conditions were identified which permitted the deposition of silicon oxycarbide films with a dielectric constant of 3.74 and a Cu diffusion depth of 29nm after thermal stressing (400C, 3h). The Cu diffusion depth was defined to be the Cu and dielectric interfacial region with a 3 orders-of-magnitude reduction in Cu concentration. A multilayered structure (diamond/SiOC/Cu/TaN/Si) was fabricated. The composition of the films was studied by using Fourier-transform infra-red spectroscopy. Secondary ion mass spectrometry was used to investigate Cu diffusion in the films.

Low Dielectric Constant a-SiOC:H Films as Copper Diffusion Barrier. Y.W.Koh, K.P.Loh, L.Rong, A.T.S.Wee, L.Huang, J.Sudijono: Journal of Applied Physics 2003, 93[2], 1241-5