Numerous applications are known in which it is desired to selectively etch one material relative to another. For instance, it is frequently desired to selectively etch silicon nitride relative to metal nitride (with exemplary metal nitride being titanium nitride, tantalum nitride, hafnium nitride, aluminum nitride, etc.). For purposes of interpreting this disclosure and the claims that follow, an etch is considered to be selective for a first material relative to a second material if the etch removes the first material at a faster rate than the second material, which can include, but is not limited to, etches which are 100% selective for the first material relative to the second material.
Among the applications in which it can be desired to selectively etch silicon nitride relative to metal nitride are applications in which silicon nitride lattices are patterned to support metal nitride-comprising capacitor containers, such as, for example, processing analogous to that described in United States Patent Application Publication number 2005/0054159.
It is desired to develop new methods for utilizing lattices to support capacitor storage nodes. It is further desired to develop new methods for selectively etching silicon nitride relative to conductive material, and it would be particularly desirable for such methods to be applicable to processes in which silicon nitride lattices are patterned to support capacitor containers. It is further desirable to develop new methods for selectively etching one material relative to another.