Process Variations and Layout Design in IC Design
Process modeling advances allow the designer to assess, analyze and predict manufacturing behavior of components under other-than-nominal conditions.
by J. A. Torres and C.N. Berglund
Traditionally, IC designers have relied on a hands-off approach in which geometric and connectivity design rules determine the manufacturability of a particular product. The necessity of capturing processing effects in geometric rules was, in part, based on the lack of adequate models (accurate and fast). However, there are a number of effects, ranging from optical to chemical to electrical, that can be only partially addressed by the existing geometry-centric design rules as proven by many studies that consistently demonstrate how random yield-loss mechanisms have been surpassed by systematic yield-loss contributions.1 Advances in process modeling have demonstrated the feasibility of compact process models to predict manufacturing behavior at conditions other-than-nominal. 2 Although there is no shortage of ideas about the objective of DFM, the industry lacks a wide consensus on the meaning of manufacturability.
Due to the equations in this article, we have made a PDF available for you to download.