A method and apparatus for removing residue, such as etch reside, from a substrate with substantially reduced damage to the substrate in a plasma processing system is described. A plasma ashing process comprising carbon dioxide (CO.sub.2) and optionally a passivation gas, such as a hydrocarbon gas, i.e., C.sub.xH.sub.y, wherein x, y represent integers greater than or equal to unity, is used to remove residue while reducing damage to underlying dielectric layers. Additionally, the process chemistry can further comprise the addition of an inert gas, such as a Noble gas (i.e., He, Ne, Ar, Kr, Xe, Rn).