Etch and strip induced material modification of porous low-k (k=2.2) dielectric

XPS analysis on the sidewall surface of Orion2.2, a CVD SiOC type low-k dielectric (k approximate to 2.2), has been performed to study the modification of low-k material during etching and strip. The sidewall surface etched in Ar/CF4/CH2F2/O-2 consists of two layers, a CFx polymer and behind that a SiOC(F) layer. No carbon depletion was observed on the sidewall surface due to protection by the CFx polymer layer against plasma damage. All plasma strip using CF4/O-2, N-2/O-2, N-2/H-2 or H-2/He chemistry remove CFx polymer layer and PR efficiently, however it gives C-depletion of low-k material. The strip using H-2/He has minimum damage of low-k material and no N contamination although it cannot eliminate fluorine contamination, which may cause voids in low-k material. (C) 2004 Elsevier B.V. All rights reserved.