Physical failure analysis deprocessing and cross-section techniques for Cu/low-k technology

In this paper, physical failure analysis (FA) techniques including interconnect level and gate level deprocessing techniques and cross section analysis that have been developed will be discussed. Deprocessing techniques discussed include: wet chemical etching, reactive ion etching (RIE), parallel polishing, chemical mechanical polishing (CMP), and combinations of these techniques. Moreover. the detailed characterization of CMP process and gate level deprocessing will be presented. For the cross-section analysis of copper/low-k samples, focused ion beam (FIB) and mechanical polishing techniques will be discussed. FA challenges and new failure modes and reliability issues will also be addressed.