Dummy Metal Insertion Based on Density Gradient Minimization with Coupling Constraints
Date Issued
2007
Date
2007
Author(s)
Chou, Szu-Jui
DOI
en-US
Abstract
As IC process geometries shrink to 65nm and below, the post-CMP dielectric thickness variation control becomes a dominant technique for manufacturability. To improve CMP quality and enhance the yield, layout uniformity is necessary. Dummy metal insertion is a general method to achieve layout uniformity in the post-routing stage. The post-CMP thickness would be affected by the variation and the gradient of metal density, which can be both minimized during the dummy insertion. However, inserting dummy features would increase coupling capacitance and timing delay. Thus, the coupling constraints need to be considered. In this thesis, we propose a dummy metal insertion algorithm considering gradient minimization and coupling constraints simultaneously. The framework contains coupling constraints regulation, multilevel dummy density analysis, and ILP-based fill synthesis with dummy number minimization. Experiments show that our method can achieve more balanced metal density distribution while using fewer dummy features, with an acceptable timing overhead.
Subjects
虛擬填充
耦合電容
梯度
平坦化
密度分析
dummy insertion
coupling
gradient
smoothness
density analysis
Type
thesis
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