Design for manufacturing (DFM) refers to various “design rules” that are implemented during the design of integrated circuits (IC(s)) to improve the manufacturability of the ICs. More specifically, design rules are rules that are intended to ensure that ICs can be manufactured with economical yields and ensure that ICs possess sufficient reliability in operation. Design rules are often set by semiconductor manufacturers (i.e., “foundries”) based on manufacturing process constraints. In particular, the trend towards smaller and smaller nodes has challenged foundries to overcome the limitations of various photolithographic, chemical, and mechanical processes with respect to the accuracy and the precision of feature dimensions and positioning. For example, diffraction effects and variations in mask placement, depth of focus, and light intensity can affect the accuracy and precision with which shapes (i.e., IC components) can be patterned on wafers. IC designs that do not account for such effects can result in higher rates of manufacturing defects occurring due, for example, to pinched, broken, or shorted components. To improve yields and reliability, foundries often specify design rules that control various dimensional parameters of IC designs by mandating, among other things, minimum space checks, minimum width checks, minimum area overlap checks, and minimum area variability checks on IC designs prior to accepting an IC design for fabrication. As process nodes have become smaller and smaller, foundries have generally implemented design rules of increasing complexity.
USPTO Backgrounds
USPTO Backgrounds