Method of reworking structures incorporating low-k dielectric materials

Low-k dielectric films such as SiLK are desirably used in semiconductor structures, for example in back-end multilevel metal interconnect structures, as insulators. Low-k dielectric films, however, are prone to damage in the course of typical rework processes such as chemical-mechanical polishing, plasma/reactive ion etching, or wet chemistry processing/etching. The present invention uses an ion milling process with a variable-position endpoint detector to unlayer multiple layers including low-k dielectric films. The ion milling process can be controlled for each material type so as to maintain a planar surface with minimal or no damage to the exposed materials. A different methodology describes unlayering individual die involving in each case mechanical polish of removal of the metal layer and metal interconnection combined with RIE or Plasma deprocessing steps.