A Legalized Method for Mixed Height Standard Cell Circuit Design

Abstract

The invention relates to a legalized method used for mixed height standard cell circuit design. The technical scheme of the method comprises the following key points: (1) according to a cell position sequence obtained according to a global layout, carrying out relaxation on the right boundary constraint of a layout area, and converting a legalization problem of a mixed height standard cell into a corresponding LCP (Linear Complementary Problem), wherein the legalization problem can be effectively solved by an existing optimization method; (2) carrying out decomposition on a matrix in the converted LCP in a proper way, and using MMSIM (Matrix MultiSplitting Iterative Method) to solve the converted LCP, wherein the proper matrix decomposition meets MMSIM convergence requirements, and meanwhile, calculation time is greatly quickened; and (3) by use of the method, simultaneously optimizing all cells instead of optimizing cells one by one, and considering the legalization problem from a global perspective. An experiment result indicates that an efficient and practical legalization result (especially for a large-scale living example) can be provided, and the requirement of a mixed height standard cell legalization stage of existing VLSI (Very Large Scale Integration) can be met.

Description

technical field [0001] The invention relates to the technical field of VLSI physical design automation, in particular to a legalization method for mixed height standard unit circuit design. Background technique [0002] With the increasing complexity of modern circuit designs, standard cells often produce different cell heights based on characteristics such as area, power, and speed. For example, taller cells can give greater driving force and better routability, while requiring greater area and power costs. Conversely, shorter cells have poorer driving force and routability, but require less area and power costs. Therefore, in order to meet various circuit design requirements, circuits of mixed-height standard cells have become more and more popular. Simple standard cells are designed as a single-row-height structure, while complex standard cells are designed as multiple The row height structure. [0003] A modern layout process usually includes three main stages: (1) gl...

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Problems solved by technology

[0005] There are two problems in the existing legalization methods of mixed height standard units: (1) they all use heuristic method to legalize the units one by one, and the angle of dealing with the problem is too partial; (2) they lack theoretical basis and cannot be very Good Quality Guaranteed Legalization

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