Devices in modern technologies have complex architectures, small feature sizes, and diverse materials. The close proximity of dissimilar materials leads to unusual fracture behaviors. A scientific understanding of these behaviors is significant for the development of the future technology. In particular, rate processes, such as creep, subscritical cracking, and ratcheting, limit the long term reliability of the interconnects. Drawing on recent experiments and models, this talk describes a channel crack in a brittle film on an underlayer. When the underlayer is compliant (e.g., a low k dielectric), the driving force on the channel crack is very large. When the underlayer creeps (e.g., a polymer), the crack velocity is set by the viscosity in the underlayer, as well as by subcritical cracking in the brittle film. When the underlayer is plastically deformable (e.g., a metal), on thermal cycling, the crack can grow in the brittle film by ratcheting deformation in the underlayer. I also discuss the use of these phenomena to measure mechanical properties at the small scale. PDF files of papers are available at http://www.princeton.edu/~suo/ Keywords: Interconnects, fracture, creep, plasticity.