Method of pattern etching a low k dielectric layer

Abstract

A first embodiment of the present invention pertains to a method of patterning a semiconductor device conductive feature while permitting easy removal of any residual masking layer which remains after completion of the etching process. A multi-layered masking structure is used which includes a layer of high-temperature organic-based masking material overlaid by either a patterned layer of inorganic masking material or by a layer of patterned high-temperature imageable organic masking material. The inorganic masking material is used to transfer a pattern to the high-temperature organic-based masking material and is then removed. The high-temperature organic-based masking material is used to transfer the pattern and then may be removed if desired. This method is also useful in the pattern etching of aluminum, even though aluminum can be etched at lower temperatures. A second embodiment of the present invention pertains to a specialized etch chemistry useful in the patterning of organic polymeric layers such as low k dielectrics, or other organic polymeric interfacial layers. This etch chemistry is useful for mask opening during the etch of a conductive layer or is useful in etching damascene structures where a metal fill layer is applied over the surface of a patterned organic-based dielectric layer. The etch chemistry provides for the use of etchant plasma species which minimize oxygen, fluorine, chlorine, and bromine content.