Density gradient minimization with coupling-constrained dummy fill for CMP control

In the nanometer IC design, dummy fill is often performed to improve layout pattern uniformity and the post-CMP quality. However, filling dummies might greatly increase interconnect coupling capacitance and thus circuit delay, and might also lead to explosion of mask data due to the extra layout patterns. Traditional dummy-fill algorithms try to make each tile (window) density satisfy foundry’s density upper and lower bounds under the coupling constraint. As technology advances, however, it is not sufficient to just keep the pattern density variation of each layer within density bounds. The density gradient, besides the density variation, plays a pivotal role in determining the post-CMP thickness of modern circuit designs. In this paper, we present the first gradient-driven dummy-fill algorithm to address the density gradient and other classical objectives (such as density variation, coupling constraints, dummy count) as well. Our dummy-fill algorithm has the two distinguished...

• Type: Conference
• Year: 2010
• Where: ISPD
• Authors: Huang-Yu Chen, Szu-Jui Chou, Yao-Wen Chang
• Keywords: Coupling Constraints, Density Gradient, Density Variation, Hardware, ISPD 2010