US Patent 7253100 Reducing damage to ulk dielectric during cross-linked polymer removal

Methods are disclosed for reducing damage to an ultra-low dielectric constant (ULK) dielectric during removal of a planarizing layer such as a crosslinked polymer. The methods at least partially fill an opening with an at most lightly crosslinked polymer, followed by the planarizing layer. When the at most lightly crosslinked polymer and planarizing layer are removed, the at most lightly crosslinked polymer removal is easier than removal of the planarizing layer, i.e., crosslinked polymer, and does not damage the surrounding dielectric compared to removal chemistries used for the crosslinked polymer.