SIMS study of Cu trapping and migration in low-k dielectric films

A 545 nm thick low-k dielectric film was implanted at room temperature with 50 keV 63Cuþ to a dose of 1:0 1014 atoms/ cm2. The film is a SiOx-based material and doped with about 8 at.% of flourine. Analyses by secondary-ion mass spectrometry show that Cu is fast diffuser in the low-k film, and after the RTA anneals Cu has redistributed within the film and some Cu has migrated to the interface between the low-k film and Si substrate. At 800 8C RTA, the apparent ‘‘diffusion’’ coefficient in the implanted film, DA, is estimated as 1:5 10 9 cm2/s. The 1100 8C RTA sample was re-analysed after stripping the low-k film and the result showed that 4:0 1012 atoms/cm2 Cu had moved into the silicon substrate to a depth of about 170 nm. # 2004 Elsevier B.V. All rights reserved