April 18, 2007
With decreasing on-chip clock periods, the timing characteristics of on-chip signals need to be determined and controlled more precisely. Accurate interconnect models are therefore critical to the IC design process. In this dissertation, two global interconnect models are presented. Closed-form expressions of the signal waveform are developed, which achieve good agreement with Spectre simulations.
During the interconnect design process, multiple design criteria are considered, such as delay, power, bandwidth, and noise. Repeaters are widely used in digital ICs to reduce interconnect delay and signal transition time with the penalty of additional power and area. A repeater insertion methodology is presented for achieving a tradeoff among different design criteria. Closed-form expressions for the number and size of the power optimal repeaters are developed.
With the scaling of CMOS technology, the requirements of different design criteria have become more stringent. It is increasingly difficult for conventional copper interconnect to satisfy these requirements. On-chip optical interconnect is shown to be a promising substitute for electrical interconnect in future advanced architectures. Critical lengths at which optical interconnect becomes advantageous are shown to be approximately one tenth of the chip edge length at the 22 nm technology node.
The focus of the IC design process in the DSM regime has shifted from logic optimization to interconnect optimization. The research presented in this dissertation provides several interconnect design and modeling methods to support this interconnect-centric design strategy.