Structural stability of tight-pitched damascene interconnects

Mukesh, Sagarika; Lanzillo, Nicholas A.; Motayama, Koichi; Spooner, T.

doi:10.1109/iitc47697.2020.9515651

Cited by 1 publication

(1 citation statement)

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“…This coupled with a cohesive force analysis which shows that Cu has lower cohesive energy than the alternate metals implies that the alternate metals have a lower tendency to diffuse into the surrounding dielectric material, so they do not need a thick diffusion barrier unlike Cu [17]. On the other hand, this also implies that these alternate metals have a higher tendency to form surfaces, which may lead to pattern collapse at small pitches, as shown using finite-element analysis in [18], [19]. So, a trade-off between the advantages of lower resistance and improved reliability over Cu and the structural stability of these alternate metal interconnects needs to be analyzed.…”

Section: Introductionmentioning

confidence: 95%

A Multiscale Simulation Study of the Structural Integrity of Damascene Interconnects in Advanced Technology Nodes

Mukesh¹,

Lanzillo²

2023

IEEE Trans. Electron Devices

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The structural stability of damascene interconnects for back-end-of-line (BEOL) technologies is analyzed using a combination of force-field based molecular dynamics simulations and finite-element modeling. The candidate metals analyzed are-ruthenium, cobalt, tungsten, and copper. Cohesive traction and normal bonding energy are calculated using force-field based molecular dynamics simulations and then fed as input to a finiteelement analysis (FEA) tool, where their dependence on physical dimensions of the interconnect lines is studied. The characteristics of these metals are compared against the characteristics of copper. The parameters studied for the BEOL structures are sidewall angle, aspect ratio, internal stress of the metal, and modulus of elasticity of the dielectric material around the metal at 18 nm pitch. Generally, lower aspect ratio and higher modulus of elasticity of the dielectric results in structures that show a lower tendency to collapse. Intrinsic stress of the metal and side wall angle have a minor impact on the overall stability. Based on this study, cobalt is most stable alternate metal amongst Ru, Co, and W.

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Section: Introductionmentioning

confidence: 95%