Turing-patterned Ta<sub>2</sub>S<sub>3</sub> enables sub-2 nm diffusion barrier for advanced Cu interconnects.

Tian, Xu; Yang, Songjie; Liu, Xiaoyu; Tang, Yupu; Ju, Shanshan; Lei, Renbo; Li, Jinxiong; Ding, Yuancan et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

As semiconductor technology advances towards the 15-Å node and beyond, the back-end-of-line (BEOL) metal interconnect technology encounters severe scaling challenge, because the conventional barrier/liner TaN/Ta(Co) bilayer cannot be proportionally thinned down as the pitch size shrinks. This challenge arouses significant resistance-capacitance (RC) delay that is currently the bottleneck for advanced integrated circuits. Herein, we propose a Turing-patterned Ta<sub>2</sub>S<sub>3</sub> (Tp-Ta<sub>2</sub>S<sub>3</sub>) thin barrier to address the above interconnect scaling challenge. The Tp-Ta<sub>2</sub>S<sub>3</sub>, synthesized by a particularly designed energy-enhanced atomic layer deposition (ALD) process, features a labyrinthine stripe morphology with an intertwined layer structure, which can significantly enhance its Cu diffusion barrier performance by forcing the Cu atoms to migrate a significantly longer path through the 2D interlayer space. The synthesized Tp-Ta<sub>2</sub>S<sub>3</sub> barrier with only 1.2 nm thickness exhibits excellent Cu wettability, remarkably strong adhesion, and much better barrier performance than the state-of-the-art TaN barrier.