This research combines experimental and modeling activities that are integrated by the use of scanning force microscopy to measure the effects of different processing parameters on dielectric properties and deformation in Cu-damascene interconnect structures with nanoscale resolution. We utilize electrostatic force microscopy to detect undesirable dielectric constant gradients that are caused by plasma processing during dielectric deposition, reactive ion etching of the circuit pattern, oxidizing plasma removal of photoresist, and adhesion enhancement with inert gas plasmas. This will help optimize plasma processing parameters to minimize or eliminate dielectric degradation during manufacturing. In our study of nanoscale deformation, scanning force microscopy (SFM) is used to measure the out-of-plane deformation resulting from thermal cycling with nanometer scale resolution. In parallel, finite element strategies to model interfacial sliding and diffusive deformation are being developed and used to predict deformation in interconnect structures. These predictions are validated using our SFM method so the models can be used as reliable design tools to predict deformation during thermal processing.
The broader technological impacts of this work include a significant collaboration between UNH and two major semiconductor manufacturers, IBM and Intel, technology transfer of a new dielectric imaging technique to industry and a development of an experimentally verified model of nanoscale deformation that will be useful to the interconnect industry and other nanomanufacturing areas such as MEMS and NEMS. The broader educational impacts include graduate education in a technologically important area, incorporation of a real world project in undergraduate engineering courses, and enhanced participation of women in science by the support of a female graduate student in an interdisciplinary setting.
