Method and apparatus for selective in-situ etching of inter dielectric layers

摘要

A method and apparatus for selectively etching interlayer dielectrics (ILDs) using a focused ion beam and an etch-assisting gas are described. The method and apparatus can be used to distinguish ILDs in imaging or to etch ILDs without etching other layers. The etch-assisting gas molecule includes an etching portion that forms volatile compounds with the substrate upon when a reaction is initiated by the ion beam and a functional group that increases the stickiness of the molecule so that a sufficient number of molecules are adsorbed on the surface.