Anisotropic etching of organic-containing insulating layers

Abstract

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.