The 0.13 mum technology uses Cu/low k materials for back-end-of-line (BEOL) process. In this paper, we studied and compared impact of etching and photoresist stripping (PRS) plasma on the physical and chemical properties of two CVD low k SiOCH films, Coral(TM) and Black Diamond(TM). They were treated with etching (C4F8/N-2/Ar) and O-2 or forming gas PRS plasma. The etching plasma did not cause Si-CH3/Si-O degradation when compared to the PRS treatments. Forming gas PRS caused substantial -CH3 loss and surface C depletion for both SiOCH films, especially for films treated with harsh processing conditions. O-2 PRS on low k films performed better than forming gas in terms of Deltak/k(0), C depletion and stability of Si-CH3/Si-O based on the k value comparison, surface and FTIR analyses. Moreover, soft O-2 PRS effectively removed C built-up on film surface after etching. The surface roughness and PRS etching rates of both films were also studied and compared. We had therefore successfully developed the soft O-2 plasma chemistry as a suitable PRS recipe for integration of Cu/CVD low k BEOL interconnects. (C) 2004 Elsevier B.V. All rights reserved.