Physical Characterization of PECVD and PEALD Ru(-C) Films and Comparison with PVD Ruthenium Film Properties

Wojcik, H.; Junige, Marcel; Bartha, W.; Albert, Matthias; Neumann, Volker; Merkel, U.; Peeva, A.; Gluch, Jürgen; Menzel, S.; Munnik, F.; Liske, R.; Utess, D.; Richter, Inka; Klein, Christoph; Engelmann, Hans‐Jürgen; Ho, Paul S.; Hoßbach, Christoph; Wenzel, Christian

doi:10.1149/2.066202jes

Cited by 21 publications

(14 citation statements)

References 47 publications

(51 reference statements)

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“…Compared with other ALD processes using Ru(EtCp) 2 as a precursor, the determined GPCs are of the same magnitude. Wojcik et al reported a growth rate of 0.037 nm/cycle with a Ru(EtCp) 2 PEALD process [39] and Park et al 0.075 nm/cycle with a thermal process [34]. A higher growth rate of 0.12 nm/cycle was achieved with O 3 as co-reactant [10].…”

Section: Structural Propertiesmentioning

confidence: 99%

Growth of Atomic Layer Deposited Ruthenium and Its Optical Properties at Short Wavelengths Using Ru(EtCp)2 and Oxygen

et al. 2018

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High-density ruthenium (Ru) thin films were deposited using Ru(EtCp)2 (bis(ethylcyclopentadienyl)ruthenium) and oxygen by thermal atomic layer deposition (ALD) and compared to magnetron sputtered (MS) Ru coatings. The ALD Ru film growth and surface roughness show a significant temperature dependence. At temperatures below 200 °C, no deposition was observed on silicon and fused silica substrates. With increasing deposition temperature, the nucleation of Ru starts and leads eventually to fully closed, polycrystalline coatings. The formation of blisters starts at temperatures above 275 °C because of poor adhesion properties, which results in a high surface roughness. The optimum deposition temperature is 250 °C in our tool and leads to rather smooth film surfaces, with roughness values of approximately 3 nm. The ALD Ru thin films have similar morphology compared with MS coatings, e.g., hexagonal polycrystalline structure and high density. Discrepancies of the optical properties can be explained by the higher roughness of ALD films compared to MS coatings. To use ALD Ru for optical applications at short wavelengths (λ = 2–50 nm), further improvement of their film quality is required.

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Section: Structural Propertiesmentioning

confidence: 99%

Growth of Atomic Layer Deposited Ruthenium and Its Optical Properties at Short Wavelengths Using Ru(EtCp)2 and Oxygen

et al. 2018

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“…Ru-Ta alloy has been investigated and the evaluation results of film property such as wettability and barrier property have been reported. [27][28][29][30] However, the filling property of Cu electroplating and the reliability performance z E-mail: torazawa.naoki@jp.panasonic.com with Ru-Ta alloy and RuTa(N) film which is doped with N in RuTa using fine Cu damascene structure have not been reported.In this paper, Ru-Ta alloy was applied as the diffusion barrier layer in fine Cu dual damascene interconnects, and the film property, filling property of Cu electroplating and reliability performances were investigated. The film which Nitrogen (N) was incorporated into Ru-Ta film was also evaluated, and the barrier structure for Ru-Ta alloy was considered on the basis of the film properties.…”

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confidence: 99%

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confidence: 99%

The Development of Cu Filling and Reliability Performance with Ru-Ta Alloy Barrier for Cu Interconnects

Torazawa

Hirao

Kanayama

et al. 2016

J. Electrochem. Soc.

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Ru-Ta alloy was investigated as the diffusion barrier layer in Cu dual damascene interconnects, and Cu filling property and reliability performances with RuTa/RuTa(N) stacked barrier structure were mainly evaluated. RuTa strongly orientated to Ru(002) and the lattice misfit between Ru(002) and Cu(111) was lower than that between Ta(110) and Cu(111). The wettability of Cu seed on RuTa was much better than that on Ta. The barrier property against Cu diffusion of RuTa/RuTa(N) stacked barrier structure kept the equivalent barrier property of conventional Ta/TaN one. Filling property of Cu electroplating was improved by using Ru-Ta alloy barrier, and trenches of 45 nm in width could be filled successfully due to the suppression of the agglomeration of Cu seed on the sidewall of trench. Via resistance with RuTa/RuTa(N) barrier was much lower than that with Ta/TaN one due to its low resistivity. The estimated life time of via electromigration with RuTa/RuTa(N) barrier was longer than that with Ta/TaN one because of the good wettability and filling property inside via. Consequently, Cu filling property and reliability performance can be improved with RuTa/RuTa(N) stacked barrier structure in Cu interconnects. Copper (Cu) interconnects have been applied to ultra large scale integrated circuits (ULSIs) to reduce the resistance of wiring and resistive-capacitive (RC) delay since the introduction of 130 nm complementary metal oxide semiconductors (CMOSs). As the feature size of trench and via continues to shrink, filling the gaps with Cu electroplating becomes more difficult. For perfectly gap filling, the opening of trench and via after the deposition of barrier and Cu seed have to be kept enough by thinning barrier and/or Cu seed. However, thinning Cu seed leads to Cu being agglomerated on the sidewall of both trench and via where Cu seed is too thin due to its poor coverage, resulting in the formation of voids inside trench and via. Therefore, one challenging issue for Cu interconnects is to fill trench and via completely without the agglomeration of Cu seed on the diffusion barrier layer.New barrier metals that have better wettability with Cu than conventional Tantalum (Ta) have been studied to achieve continuous and smooth Cu film on them.1-26 Among them, Cobalt (Co) and Ruthenium (Ru) have been most frequently suggested for suppressing the agglomeration of Cu seed. Co is known to have the good film properties such as the low resistivity, the high melting point and the good adhesion with Cu. However, Co has the serious problems with chemical mechanical polishing (CMP) process and wet etching process. Co is corroded readily during CMP process and wet etching process, and the slits are occurred between Cu wiring and the interlayer dielectric. It results in the degradation of the device yield and reliability performance. As for Ru, the barrier property against Cu diffusion is not enough, and CMP process for Ru is a difficult technology and the scratch occurred during CMP process leads to the degradation of the device yie...

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“…Ru has drawn much attention lately as adhesion layer and possible diffusion barrier for Cu interconnects in VLSI circuits. While the diffusion barrier properties of sputtered Ru layers are less attractive, wetting and adhesion experiments have shown promising results [5][6][7][8]. In all cases presented here, except if noted elsewise, a thin Ti layer is deposited prior to the diffusion barrier to imitate the Ti or Ti-Si contacts to the active device areas.…”

Section: Introductionmentioning

confidence: 90%

The influence of liners with Ti, Ta or Ru finish on thin Cu films

Gross

Haag

Schuster

et al. 2014

Microelectronics Reliability

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Physical Characterization of PECVD and PEALD Ru(-C) Films and Comparison with PVD Ruthenium Film Properties

Cited by 21 publications

References 47 publications

Growth of Atomic Layer Deposited Ruthenium and Its Optical Properties at Short Wavelengths Using Ru(EtCp)2 and Oxygen

Growth of Atomic Layer Deposited Ruthenium and Its Optical Properties at Short Wavelengths Using Ru(EtCp)2 and Oxygen

The Development of Cu Filling and Reliability Performance with Ru-Ta Alloy Barrier for Cu Interconnects

The influence of liners with Ti, Ta or Ru finish on thin Cu films

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