Research in Physical Design of VLSI Circuits

首席研究员将研究超大规模集成电路设计模型和方法。在建模的方向上，他会找到能够准确描述物理设计过程的约束和要求的模型。在方法论方向上，他将运用算法技术来设计自动化问题，这些问题是数学的和形式化的，以便在实验之前对它们进行评估和分析。刘教授将集中讨论以下主题：(1)二维布局问题的方法；(2)将平面规划技术扩展到非切片模块和L形结构；(3)研究可能受益于并行计算的算法，例如同步全局路由。本研究解决了快速生产高效运行的超大规模集成电路（VLSI/ULSI）布局的需求。随着此类设备变得越来越复杂，行业竞争日益激烈，这种需求已经变得至关重要。在VLSI/ULSI设计中有许多解决问题的方法；然而，他们面临着两个问题之一。要么是设计方法是启发式的，可能会因为分析方法不完善而意外失败；或者形式化算法，虽然很容易理解，但当涉及到非常大的电路时，会花费太多时间。基本需求是更现实和复杂的计算模型和新的分析方法，这将导致高效的VLSI/ULSI设计方法。刘教授建议解决VLSI理论中的研究问题（如平面规划、布线和并行设计技术），并将解决方案以软件形式进行进一步研究。在过去的几年里，首席研究员将注意力转向了VLSI，他在理论方面做出了重要贡献，同时也考虑到了实际问题。

The principal investigator will do research on VLSI design models and methodologies. In the direction of modeling, he will find models that describe accurately the constraints and requirements of the physical design process. In the direction of methodologies, he will apply algorithmic techniques to design automation problems, which are mathematical and formal, so that they can be evaluated and analyzed prior to experimentation. Professor Liu will concentrate on these topics: (1) two-dimensional approaches to the layout problem; (2) the extension of floorplanning techniques to non-slicing modules and L- shaped structures; and (3) the investigation of algorithms that might profit from parallel computation, e.g. simultaneous global routing. This research addresses the need to produce rapidly layouts of very and ultra large-scale integrated (VLSI/ULSI) circuits which operate efficiently. It is a need that has become of paramount importance as such devices become more complex and the industry increasingly competitive. There are many approaches to problems in VLSI/ULSI design; however they suffer from one of two problems. Either the design methods are heuristic and can fail unexpectedly because analysis methods are not well developed; or formal algorithms, which are well understood, take too much time when very large circuits are involved. The basic need is for more realistic and sophisticated models of computation and new analysis methods that will lead to efficient VLSI/ULSI design methods. Professor Liu proposes to solve research problems in VLSI theory (e.g. floorplanning, routing and parallel design techniques) and put the solutions in software form to further study them. The principal investigator has, in the past several years, turned his attention to VLSI, where he has made important contributions to theory while keeping practical problems in mind.