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Promising interconnect materials continue to emerge and are considered as potential replacements for Cu interconnects. In this article, an interconnect technology/system codesign methodology is presented to efficiently optimize generic interconnects using ballistic materials. The key requirements of material-level characteristics to replace conventional Cu counterparts are quantified, such as the channel density, mean free path (MFP), and contact resistance. Furthermore, to achieve maximal chip-level throughput, two interconnect design schemes are proposed and optimized under a given number of metal layers, die area, and power density constraints. Results demonstrate that the optimal design scheme strongly depends on the power constraint, driving devices as well as material parameters, including the contact resistance. It is shown that up to 45% of the throughput improvement can be achieved by replacing both local and intermediate Cu interconnects at an ultralow-power budget. [ABSTRACT FROM AUTHOR]

The advent of multigate transistor technology for 20-nm technology node and beyond, has increased the importance of wire parasitics, in particular, wire resistance in determining the circuit delay computation. Variability in wire dimensions directly impacts the wire parasitics, hence, the overall system performance. For the first time, in this paper, we study circuit variability for 11- and 7-nm technology nodes based on GDSII-level layouts. We propose novel hybrid multipatterning flows, which combine the litho-etch-litho-etch and self-aligned-spacer technologies, to reduce circuit variability induced by the lithography process. We engineer the hybrid solutions to have reduced variability in wire resistance, and circuit performance, and develop variability models for each patterning proposal. We also find the increasing need of these hybrid solutions at the 7-nm technology node. For Extreme Ultraviolet (EUV) lithography to enable higher circuit performance than the proposed patterning regimes, it requires a high precision in core variation of less than 1 nm. [ABSTRACT FROM AUTHOR]

Based on realistic circuit- and system-level simulations, graphene interconnects are analyzed in terms of multiple material properties, such as the mean free path (MFP), the contact resistance, and the edge roughness. The benchmarking results indicate that the advantage of using graphene interconnects occurs only under certain circumstances. The device-level parameters, including the supply and threshold voltages, and the circuit-level parameters, including the wire length and width, have large impacts on both the delay and energy-delay product (EDP). At the circuit level, one representative circuit, a 32-bit adder, is investigated, where up to 40% and 70% improvements in delay and EDP are observed. At the system-level analysis, an ARM Cortex-M0 processor is synthesized, and placement and routing are performed. After replacing copper interconnects with multilayer graphene interconnects, up to 15% and 22% performance improvements in clock frequency and EDP have been observed. It is also demonstrated that the benefits of using graphene for the ARM core processor are strongly dependent on the quality of the graphene, such as the MFP and the edge roughness. [ABSTRACT FROM AUTHOR]

To suppress the impact of size effects on sub-20 nm wide wires, a novel aluminum-copper hybrid interconnect architecture is proposed and its potential performance has been quantified. Al wires offer lower resistivities at nanoscale dimensions because they do not need diffusion barriers, and size effects are less prominent in them due to their smaller bulk mean free path. However, their current conduction capacity is substantially lower than that of Cu wires. To get around this limitation, this letter proposes a hybrid interconnect technology to replace only short narrow local signal wires by Al wires. This scheme takes advantage of the fact that signal wires conduct bi-directional currents and are therefore virtually immune to electromigration. The improvement in chip clock frequency is predicted to be between 50% and 100% for the 7 nm technology node. [ABSTRACT FROM PUBLISHER]