Abstract :
Due to significantly reduced material properties relative to Si02, low-k dielectric materials present considerable thermal, mechanical, and electrical reliability concerns when integrated as the interlayer dielectric in Cu interconnect structures. The complex chemical structure and presenceofnanoporosityinlow-kmaterialsalsopresentsignificantchallenges in the fabrication and characterization of nano-patterned metal interconnects. In this address, these challenges and their origin will be briefly reviewed and recent progress in understanding the structure-property relationships in lowk dielectric materials will be presented along with new advances in materials metrologies that enable the characterization and failure analysis of low-k materials and Cu interconnects at the nanometer scale. Specific topics likely to be covered will include: photoelectron and electron energy loss spectroscopy measurements to map the band alignment (i.e. "band diagram) and presence of defect states in low-k/Cu interconnects, nano-scale AFM based FTIR measurements to elucidate the chemical structure of nano-patterned low-k materials; and optical and AFM based measurements to deduce the mechanical properties of nanometer scale thin films and metal interconnect structures. It will be demonstrated that these techniques, when combined with constraint and bond rigidity percolations theories, can enable a greater understanding of the structure-property relationships in low-k materials that should enable a more rational design of future ultra low-k materials for metal interconnects with improved reliability.
