Hard masking method for forming oxygen containing plasma etchable layer

Abstract

A method for forming a patterned layer within a microelectronics fabrication. There is first provided a substrate employed within a microelectronics fabrication. There is then formed over the substrate an oxygen containing plasma etchable layer, where the oxygen containing plasma etchable layer is formed of a material which is also susceptible to etching within a fluorine containing plasma. There is then formed upon the oxygen containing plasma etchable layer a hard mask layer. There is then formed upon the hard mask layer a patterned photoresist layer. There is then etched through use of a first anisotropic plasma etch method the hard mask layer to form a patterned hard mask layer while simultaneously reaching the oxygen containing plasma etchable layer and while employing the patterned photoresist layer as a first etch mask layer. The first anisotropic plasma etch method employs an etchant gas composition appropriate for etching the hard mask material. There is then stripped from the patterned hard mask layer the patterned photoresist layer, where the patterned photoresist layer is stripped employing a stripping method which does not attack the oxygen containing plasma etchable layer. Finally, there is then etched through use of a second plasma etch method the oxygen containing plasma etchable layer to form a patterned oxygen containing plasma etchable layer while employing the patterned hard mask layer as a second etch mask layer, where the second plasma etch method is the fluorine containing plasma etch method. The method is particularly useful for forming patterned low dielectric constant dielectric layers within microelectronics fabrications.