Redundant via Insertion: Removing Design Rule Conflicts and Balancing via Density

Song CHEN  Jianwei SHEN  Wei GUO  Mei-Fang CHIANG  Takeshi YOSHIMURA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E93-A   No.12   pp.2372-2379
Publication Date: 2010/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E93.A.2372
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Physical Level Design
Keyword: 
redundant via,  double via,  design for manufacturability,  via density,  

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Summary: 
The occurrence of via defects increases due to the shrinking size in integrated circuit manufacturing. Redundant via insertion is an effective and recommended method to reduce the yield loss caused by via failures. In this paper, we introduce the redundant via allocation problem for layer partition-based redundant via insertion methods [1] and solve it using the genetic algorithm. At the same time, we use a convex-cost flow model to equilibrate the via density, which is good for the via density rules. The results of layer partition-based model depend on the partition and processing order of metal layers. Furthermore, even we try all of partitions and processing orders, we might miss the optimal solutions. By introducing the redundant via allocation problem on partitioning boundaries, we can avoid the sub-optimality of the original layer-partition based method. The experimental results show that the proposed method got 12 more redundant vias inserted on average and the via density balance can be greatly improved.