Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects

Hsu, Kuo Chung; Perng, Dung Ching; Yeh, Jia Bin; Wang, Yi Chun

doi:10.1016/j.apsusc.2012.04.046

Cited by 24 publications

(7 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Amorphisation is likely to be promoted by the addition of W. The reduction in the number of grain boundaries of a change towards an amorphous structure is a beneficial key aspect in the performance of diffusion barrier layers/films. A similar effect was observed with the addition of Cr in Ru-Cr films [15]. It is noteworthy that the flat substrate experimental approach herein used does not replicate the high aspect ratio shape characteristic of narrow interconnects; filling narrow vias/lines with Cu is a challenge itself.…”

Section: Resultssupporting

confidence: 63%

“…Ru is chemically inert and stable, contrasting with its counterparts, such as Co, which is prone to dissolution during conventional acidic electroplating, requiring electrolyte modification to be used in seedless diffusion barrier systems [11,12]. However, similar to other candidates, Ru alone is not effective as a diffusion barrier [13], thus, driving the research on coupling Ru with other species to improve the barrier properties against Cu diffusion, including Ru-Co [14], Ru-Cr [15], Ru-Mn [16][17][18], Ru-N [19], Ru-P [20,21], Ru-Ta(-N) [16,22,23], and Ru-W(-N) [16,24,25] compositions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seedless Cu Electroplating on Ru-W Thin Films for Metallisation of Advanced Interconnects

Santos

Oliveira

Savaris

et al. 2022

IJMS

View full text Add to dashboard Cite

For decades, Ta/TaN has been the industry standard for a diffusion barrier against Cu in interconnect metallisation. The continuous miniaturisation of transistors and interconnects into the nanoscale are pushing conventional materials to their physical limits and creating the need to replace them. Binary metallic systems, such as Ru-W, have attracted considerable attention as possible replacements due to a combination of electrical and diffusion barrier properties and the capability of direct Cu electroplating. The process of Cu electrodeposition on Ru-W is of fundamental importance in order to create thin, continuous, and adherent films for advanced interconnect metallisation. This work investigates the effects of the current density and application method on the electro-crystallisation behaviour of Cu. The film structure, morphology, and chemical composition were assessed by digital microscopy, atomic force microscopy, scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results show that it was possible to form a thin Cu film on Ru-W with interfacial continuity for current densities higher than 5 mA·cm−2; however, the substrate regions around large Cu particles remained uncovered. Pulse-reverse current application appears to be more beneficial than direct current as it decreased the average Cu particle size.

show abstract

Section: Resultssupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Seedless Cu Electroplating on Ru-W Thin Films for Metallisation of Advanced Interconnects

Santos

Oliveira

Savaris

et al. 2022

IJMS

View full text Add to dashboard Cite

show abstract

“…[ 176 ] The amorphous 5‐nm Ru x Cr 1− x film did not show significant interdiffusion in the Cu/Ru x Cr 1− x /Si structure for 30 min at 650 °C because of its high thermal stability. [ 178 ] The 5‐nm Ru x Mo 1− x film exhibited a 100‐fold improvement in current leakage compared to the pure Ru film. The thermal stability increased by 175 °C, resulting in a better barrier effect at the annealing temperature of 725 °C.…”

Section: Next‐generation Interconnect Materialsmentioning

confidence: 99%

Materials Quest for Advanced Interconnect Metallization in Integrated Circuits

et al. 2023

View full text Add to dashboard Cite

Integrated circuits (ICs) are challenged to deliver historically anticipated performance improvements while increasing the cost and complexity of the technology with each generation. Front‐end‐of‐line (FEOL) processes have provided various solutions to this predicament, whereas the back‐end‐of‐line (BEOL) processes have taken a step back. With continuous IC scaling, the speed of the entire chip has reached a point where its performance is determined by the performance of the interconnect that bridges billions of transistors and other devices. Consequently, the demand for advanced interconnect metallization rises again, and various aspects must be considered. This review explores the quest for new materials for successfully routing nanoscale interconnects. The challenges in the interconnect structures as physical dimensions shrink are first explored. Then, various problem‐solving options are considered based on the properties of materials. New materials are also introduced for barriers, such as 2D materials, self‐assembled molecular layers, high‐entropy alloys, and conductors, such as Co and Ru, intermetallic compounds, and MAX phases. The comprehensive discussion of each material includes state‐of‐the‐art studies ranging from the characteristics of materials by theoretical calculation to process applications to the current interconnect structures. This review intends to provide a materials‐based implementation strategy to bridge the gap between academia and industry.

show abstract

“…Additionally, there is overwhelmingly more literature on the topic of diffusion barriers than there is for liner materials, and there are few studies that examine a barrier and a liner material together, or test a material for both barrier and liner properties. Some of the materials studied as combined barrier/liner materials include NiP alloy [10], Cr [11], RuMo alloy [12], CoWB [13], Ru [14], MoC doped Ru [15], Ru(P) [16], RuCo [17], Co [18,19], Co(W) [20][21][22][23], MnN [24] and Ti [25]. There is also some precedence for building upon existing knowledge by combining known diffusion barrier and liner materials.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of tungsten or cobalt into TaN barrier layers controls morphology of deposited copper

Nies¹,

Nolan²

2023

J. Phys. Mater.

View full text Add to dashboard Cite

Progress in semiconductor devices, which has enabled the information and communications technology explosion of the 21st century, has been driven by Moore’s Law and the accompanying aggressive scaling of transistors. However, it is now acknowledged that the currently used copper interconnects are becoming a bottleneck in sub-nm scaling. Semiconductor devices require a diffusion barrier and a seed layer in the volume available to the interconnect metal. This then limits the minimum size of the interconnect and copper suffers from a preference to form 3D islands which are non-conducting rather than conducting films. Therefore there is a pressing need to either replace copper, which has its own difficulties, or to reduce the volume taken up by the diffusion barrier and liner; ideally finding a single material displaying both properties is needed. We have previously shown that incorporation of Ru into the surface layer of TaN is a strong alternative to the usual TaN/Ta or TaN/Ru stacks. In this work we study other possible metals that can be incorporated into TaN, namely Co and W, which are less expensive and critical than Ru and can potentially outperform it. Our first principles density functional theory (DFT) results from static relaxations and ab initio Molecular Dynamics (aiMD) show that there are several compositions of both Co- and W-doped TaN which should promote growth of 2D copper interconnects without compromising the barrier properties of TaN. With this selection of materials it should be possible to design new experimental processes that promote downscaled copper interconnects for the next generation of electronic devices. Additionally, our work presents an improved method towards prediction of thin film morphology on a given substrate, which can be of use for a variety of materials science applications.

show abstract

Ultrathin Cr added Ru film as a seedless Cu diffusion barrier for advanced Cu interconnects

Cited by 24 publications

References 26 publications

Seedless Cu Electroplating on Ru-W Thin Films for Metallisation of Advanced Interconnects

Seedless Cu Electroplating on Ru-W Thin Films for Metallisation of Advanced Interconnects

Materials Quest for Advanced Interconnect Metallization in Integrated Circuits

Incorporation of tungsten or cobalt into TaN barrier layers controls morphology of deposited copper

Contact Info

Product

Resources

About