采用层次式方法,分而治之,减小了电路的设计规模,非常适用于大规模的混合模式布局,并且在布局阶段结合了垂直通孔的分配问题.布局阶段的通孔分配问题不仅使得三维布局问题得以简化,而且为布线做好了准备,减少了后面的调整,是布线阶段垂直通孔分配问题的良好指导.提出了2种垂直通孔分配算法:比较精确的匈牙利近似算法;比较快速的邻域搜索方法.将这2种算法与层次式三维混合模式布局流程紧密结合,有效地解决了三维混合模式布局问题.
Hierarchical conception reduces the scale of circuit design and decreases design complexity. Considering the vertical via assignment in the placement phase is another contribution. It helps simplify 3D problem to 2D problem, and make a good route planning for the router. Hungarian approximation method and neighborhood search method are used for vertical via assignment. Some test cases show that the integration of hierarchical 3D placement algorithm and vertical via assignment is efficient for 3D mixed-mode placement.