Modification and Characterization of Interfacial Bonding for Thermal Management of Ruthenium Interconnects in Next-Generation Very-Large-Scale Integration Circuits

Abstract

Ruthenium may replace copper interconnects in next-generation very-large-scale integration (VLSI) circuits. However, interfacial bonding between Ru interconnect wires and surrounding dielectrics must be optimized to reduce thermal boundary resistance (TBR) for thermal management. In this study, various adhesion layers are employed to modify bonding at the Ru/SiO2 interface. The TBRs of film stacks are measured using the frequency-domain thermoreflectance technique. TiN and TaN with high nitrogen contents significantly reduce the TBR of the Ru/SiO2 interface compared to common Ti and Ta adhesion layers. The adhesion layer thickness, on the other hand, has only minor effect on TBR when the thickness is within 2–10 nm. Hard X-ray photoelectron spectroscopy of deeply buried layers and interfaces quantitatively reveals that the decrease in TBR is attributed to the enhanced bonding of interfaces adjacent to the TaN adhesion layer, probably due to the electron transfer between the atoms at two sides of the interface. Simulations by a three-dimensional electrothermal finite element method demonstrate that decreasing the TBR leads to a significantly smaller temperature increase in the Ru interconnects. Our findings highlight the importance of TBR in the thermal management of VLSI circuits and pave the way for Ru interconnects to replace the current Cu-based ones.

A Comparative Study and Analysis of Various Interconnects for Very Large-Scale Integration

“…The experimental results showed that, compared with copper, performance increases added with technological advancement. A study by Tianzhuo Zhan et al 10 describes how different bonding layers are used to change bonding at the Ru/SiO2 interface. Ru interconnects could eventually take the place of the recent Cu-based ones credit to thermal boundary resistance (TBR), which is used in the thermal management of VLSI circuits.…”

N-heterocyclic carbene adsorption states on Pt(111) and Ru(0001)

“…Ru is one of the most interesting metals being considered as a replacement for copper interconnects in electronics devices. 45,46 The high catalytic activity of these two metals, their increased hardness and high cohesive energies suggest that directly comparing the behaviour of NHCs on them with surface chemical reactivity elucidated primarily on gold is unwise.…”

Training dependency of neural network interatomic potential for molecular dynamics simulation of Ru-Si-O mixed system

“…5) With these advantages, studies on the demonstration of Ru interconnects have been promoted. 6) Since integrating narrow Ru buried rails surrounded by SiO 2 dielectrics requires careful assessment of stress considerations 7) and of exhaust heat considerations, 8,9) large-scale atomistic modeling of Ru interconnect/SiO 2 interlayer dielectric (Ru/SiO 2 -ILD) interfaces is of great importance.…”