Impedance characteristics of power distribution grids in nanoscale integrated circuits
Impedance characteristics of power distribution grids in nanoscale integrated circuits
复制标题
纳米级集成电路中配电网的阻抗特性
DOI：
10.1109/tvlsi.2004.836304
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发表时间：
2004
影响因子：
2.8
通讯作者：
E. Friedman
中科院分区：
文献类型：
--
作者：
A. Mezhiba;E. Friedman
纳米级集成电路的基本设计特征是增加了互连复杂性。互连层级的不同层级处的导体具有高度不同的物理特性，并且因此具有高度不同的电气特性。这些互连线还表现出电感行为，由于纳米器件的增强的开关速度，使得互连设计和分析困难。因此，为高速集成电路设计鲁棒且面积有效的配电网络已成为一项具有挑战性的任务。多层配电网的阻抗特性和相关的设计含义是本文的主题。配电网络跨越具有不同电气特性的许多互连层。与单层栅极不同，多层栅极的电特性随频率显著变化。随着频率的增加，大部分电流从低电阻的上层转移到低电感的下层。因此，多层栅格的电感随频率减小，而电阻随频率增大。多层电网的下层提供低电感电流路径，显著降低高频下的电网阻抗。多层配电网延伸到下部互连层，与仅构建在上部低电阻金属层内的配电网相比，呈现出上级高频阻抗特性。因此，用于分配全球功率的金属资源的很大一部分应该分配给较低的金属层。还提出了一个分析模型，以确定从包括个别网格层的电感和电阻特性的多层网格的阻抗特性。
The essential design characteristic of nanoscale integrated circuits is increased interconnect complexity. Conductors at different levels of the interconnect hierarchy have highly different physical and, consequently, electrical characteristics. These interconnect lines also exhibit inductive behavior due to enhanced switching speed of nanoscale devices, making interconnect design and analysis difficult. The design of robust and area efficient power distribution networks for high-speed integrated circuits has therefore become a challenging task. The impedance characteristics of multilayer power distribution grids and the relevant design implications are the subject of this paper. The power distribution network spans many layers of interconnect with disparate electrical properties. Unlike single-layer grids, the electrical characteristics of multilayer grids vary significantly with frequency. As the frequency increases, a large share of the current flow is transfered from the low-resistance upper layers to the low-inductance lower layers. The inductance of a multilayer grid therefore decreases with frequency, while the resistance increases with frequency. The lower layers of multilayer power grids provide a low-inductance current path, significantly reducing the grid impedance at high frequencies. Multilayer power distribution grids extend to the lower interconnect layers, exhibiting superior high-frequency impedance characteristics as compared to power distribution grids built exclusively within the upper, low-resistance metal layers. A significant share of metal resources to distribute the global power should therefore be allocated to the lower metal layers. An analytic model is also presented to determine the impedance characteristics of a multilayer grid from the inductive and resistive properties of the comprising individual grid layers.