challenges in 45nm cmos process
Many techniques were applied in the 45nm generation to mitigate the impact of process variation. These techniques can be characterized as pure process techniques (i.e., techniques transparent to design), combination process-design techniques (i.e., techniques that exercise tight cooperation between process and design), and pure design techniques (i.e., techniques transparent to process). Examples of pure process mitigation techniques include targeting key transistor properties to reduce random dopant fluctuation, reducing traps at the HiK+MG interface to reduce random charge variation, improving patterning techniques to reduce LER and endcap variation, and improving polishing technologies to reduce systematic cross-wafer variation. Examples of combination design-process techniques include optimizing topology, using optical proximity correction to reduce random and systematic variation, and adding dummy features to reduce systematic variation. Pure design techniques include chopping and autozeroing to compensate for random variation and common-centroid layout to compensate for systematic variation.
visit Intel technology at
http://www.intel.com/technology/itj/2008/v12i2/3-managing/4-techniques.htm