A method for
anisotropic plasma etching of organic-containing insulating
layers is disclosed. According to this method at least one opening is created in an organic-containing insulating layer formed on a substrate. These openings are created substantially without depositing etch residues by
plasma etching said insulating layer in a
reaction chamber containing a gaseous mixture which is composed such that the
plasma etching is highly anisotropic. Examples of such gaseous mixtures are a gaseous mixture comprising a
fluorine-containing gas and an
inert gas, or a gaseous mixture comprising an
oxygen-containing gas and an
inert gas, or a gaseous mixture comprising HBr and an additive. The
plasma etching of the organic-containing insulating layer can be performed using a patterned
bilayer as an etch
mask, said
bilayer comprising a
hard mask layer, being formed on said organic-containing insulating layer, and a
resist layer being formed on said
hard mask layer. A method is disclosed for forming a layer, protecting exposed surfaces of low-k dielectrics. More particularly the method comprises the steps of sealing exposed surfaces of a, preferably porous, low-k
dielectric, by forming a protective layer on exposed surfaces during or after the step of patterning openings in the porous
dielectric layers. Preferably this protective layer is formed by a N2 / O2
plasma treatment of the exposed surfaces.