Semiconductors

38 Semiconductors: Integrated Circuit Design for Manufacturability

stress are due to macroscopic, nonscalable geometries (e.g., pads, scribes,

seal rings, and package materials), which act as interfaces between the

IC circuits with submicrometer dimensions, with no air gaps or other

boundaries to divert the stress, and the large-scale outside world. Metals

and dielectrics on the semiconductor substrate are subject to stress prop-

agation, due not only to the internal die architecture, but also to the

external features required for die handling, bonding, packaging, and

applications. Mechanical failures manifest themselves a