基于28nm工艺的芯片时钟树研究

Research of Clock Tree Based on 28 nm Technology

随着工艺的不断发展,芯片集成规模增大,工作频率不断增加,给传统的IC设计带来巨大的挑战。基于UMC 28 nm工艺,采用Innovus工具布局布线,重点描述了时钟树绕线方法、early clock方法以及useful skew的应用。研究表明,采用early clock方法可以有效地解决绕线拥塞问题,最终short数量从219减少到5,并且当时钟绕线采用双倍宽度、双倍间距,应用useful skew可以将setup最差违例从-0.088 ns优化为0 ns,减少eco迭代过程。

With the development of the IC process,the scale of chip integration enlarges and the operating frequency continues to increase,which bring great challenges to the traditional IC design.Herein,Cadence Innovus,based on UMC 28 nm process library,is used to achieve a physical design in place and route flow.The early clock flow,route method for clock tree and useful skew are described in detail.It results that early clock flow can solve congestion effectively,the number of short is reduced from 219 to 5.Worst negative slack changes from-0.088 ns to 0 ns with double width and double spacing when useful skew is applied.The number of eco is reduced.