| With the continuous development of semiconductor technology,chip feature size is becoming smaller and smaller,the integration degree is becoming higher and higher,coupled with the requirements of timing power consumption manufacturability,it brings great challenges to the Electronic Design Automation.The placement and routing determines the location of cells and the selection of wiring,which directly determines the performance of the circuit,and placement and routing is the most time-consuming process in physical design.Therefore,solving the VLSI placement and routing problem more efficiently and effectively is of great significance to the design of digital integrated circuits.This work is to study the legalization in placement and the layer assignment in routing:(1)Legalization is a necessary part of the analytical placement,which aims to remove all of the overlaps among cells.In this paper,a robust negotiation-based legalizer is proposed to reduce average displacement and maximum displacement for mixed-cell-height circuits with considering the fence region and technology constraints.By dissecting the main components of the negotiation-based method,this work divides the placement grid in terms of placement sites and reformulate the legalization problem as a resource allocation task,then allow all movable cells to gradually remove overlaps in a surrounding window with two individual techniques: isolation point and adaptive penalty function.This work also adopts a deterministic multithreading technique to accelerate the convergence of the algorithm.Experimental results show that the proposed legalizer achieved the minimal average displacement and maximum displacement in a reasonable runtime compared with state-of-the-art methods.(2)Layer assignment is part of global routing,and its basic purpose is to restore planar wiring to a true three-dimensional distribution and reduce the number of vias without violating edge capacity constraints or via rules.In this paper,a net partition technology is used to first decompose the multi-pin net into two-pin sub-nets that do not intersect with each other,and based on the existing dynamic programming assignment scheme,an enhanced heuristic layer shifting method is proposed,which can control the number of vias without requiring multiple iterations.The experimental results show that the proposed method has a certain improvement effect on the minimization of the number of vias. |
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