Using the correct definition of technology node, today’s 5-nanometer generation actually corresponds to the 18-nanometer node. This is one of the key messages conveyed by the 2020 edition of the IEEE International Roadmap for Devices and Systems (IRDS). Building on what until 2015 was called ITRS (International Technology Roadmap for Semiconductors), the IRDS is an authoritative IEEE initiative with a proven track record of reliably predicting future technology challenges and solutions: for example, the transformation of the planar silicon gate CMOS to strained silicon, high-κ/metal-gate and FinFET was predicted by the ITRS as early as in 1998. In hundreds of content-packed pages, the recently released 2020 IRDS edition obviously covers many more topics, but the energy devoted by the authors to the node nomenclature issue – and the amount of exclamation points they used – deserve some extra attention.

From metal half pitch to a marketing label

Recapping the evolution of the node definitions, the IRDS authors remind readers that from 1992 to present the IC feature considered by ITRS and IRDS to name technology nodes was half pitch of the tightest metal layer, which in the past essentially coincided with the gate length. However, in the 90’s, due to the marketing pressure for a more aggressive nomenclature, the industry started using a node definition based on the average of half-pitch and gate length. Later on, some companies decided to use only the gate dimension to define the name of the technology node; and finally – according to the IRDS authors – “the technology node definition became 70% of whatever the name of the node of the previous generation was!” Therefore, the current nomenclature “has led to a complete detachment between IC features and technology nodes’ names.” As a result, the IRDS authors insist, today’s industry labeling of nodes “clearly appears completely devoted of any connection to reality.”
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