Integration of ALD barrier and CVD Ru liner for void free PVD Cu reflow process on sub-10nm node technologies

Yu, Kuo-Hui; Oie, Tomonori; F, Amano; Consiglio, Steven; Wajda, Cory S.; Maekawa, Kaoru; Leusink, Gert J.

doi:10.1109/iitc.2014.6831857

Cited by 7 publications

(5 citation statements)

References 3 publications

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“…TaN was deposited using tert-butylimido tris(ethylmethylamido)tantalum (TBTEMT, Ta(NCMe 3 )(NEtMe) 3 ) and NH 3 at 350 °C with a steady-state growth per cycle (GPC) of ~ 0.7 Å as described previously. (2) This precursor contains a Ta=N double bond which is desirable for the growth of conductive TaN films. (8,9) Among the other available four-coordinate iminotris(amido)tantalum precursors (R 1 -N=Ta(NR 2 R 3 ) 3 shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…(1) In this regard, we have previously demonstrated extendability of Cu fill (with Ru seed layer) below 25 nm linewidth (200 nm height) when PVD TaN is replaced with ALD TaN. (2) In 40 nm Cu dual damascene structures with 3 nm barrier layers, ALD TaN has also been shown to reduce via resistance by ~28% compared to PVD TaN in spite of 20x lower blanket resistivity for PVD TaN. (3) In order to further improve ALD grown TaN and minimize Cu diffusion through these ultrathin barrier films, it is desirable to avoid forming polycrystalline films with inherent grain boundary diffusion pathways.…”

Section: Introductionmentioning

confidence: 98%

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Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects

Consiglio

Dey

et al. 2015

ECS Trans.

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Ultrathin TaN and Ta1-xAlxNy films were deposited by ALD using metallorganic precursors and were evaluated for their effectiveness in Cu diffusion barrier applications compared to a PVD TaN control. Ta1-xAlxNy films with x = 0.21-0.88 were deposited by varying Ta:Al cycle ratios. The effectiveness of the barrier layers against Cu diffusion was investigated using in-situ-ramp-anneal-synchrotron-XRD on stacks with 1.8 nm layers between 50 nm PVD Cu and Si. The kinetics of Cu3Si formation was assessed by performing a Kissinger-like analysis to determine the effective activation energy (Ea) for Cu silicidation. Compared to the stack with a PVD TaN barrier, the stacks with the ALD films exhibited a higher crystallization temperature for Cu silicidation. Based on the estimated Ea values, grain boundary and lattice diffusion of Cu were identified as the dominant failure mechanisms for the ALD and PVD films, respectively. For 3 nm films, GIIXRD showed evidence of nanocrystallites embedded in an amorphous matrix with broad peaks corresponding to cubic phase for the ALD films and hexagonal phase for the PVD film. The superior performance of the ALD barriers has been attributed to the formation of a higher density cubic phase in the ALD films as compared to the lower density hexagonal phase in the PVD film. The study further elucidates the difference in initial failure mechanisms due to differences in barrier crystallinity and associated phase. Additionally, incorporation of Al in ALD Ta1-xAlxNy (x=0.33) seems to aid the formation of a barrier film which is closer to amorphous than the case of ALD TaN.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects

Consiglio

Dey

et al. 2015

ECS Trans.

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“…However, ALD TaN films contain higher impurity content than PVD TaN films resulting in higher via R and poor interface quality. Moreover, ALD barriers have not delivered on their promise as PVD Ta flash and/or PVD Cu seed layers were still needed to provide a good barrier-Cu interface [ 253 ]. Some integration schemes of modified ALD TaN Barrier with Co/Ru liner are reported to reduce line/via resistance and improve interface quality and reliability as required in advanced technology nodes.…”

Section: Metal Materials Interconnectmentioning

confidence: 99%

State of the Art and Future Perspectives in Advanced CMOS Technology

et al. 2020

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The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today’s transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore’s law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.

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“…12,13 After loading in the cluster tool, a degas/pre-cleaning step was performed and the wafers were moved to another deposition chamber without any vacuum break for ALD of TiN and TaN layers using TiCl4 and Ta(NCMe3)(NEtMe)3 (Me=CH3 and Et=C2H5) precursors, respectively, with NH3 used as a co-reactant. The steady-state growth per cycle (GPC) of ALD TaN was ~ 0.7 Å/cycle at 350 °C as described previously 14,15 and the steady-state GPC of ALD TiN was ~0.35 Å/cycle at 430 °C. The deposition of the metal nitride layer was followed by CVD of ~ 3 nm ruthenium using a Ru3(CO)12 precursor 16 .…”

Section: A Film Depositionmentioning

confidence: 99%

Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications

Dey

Yu²,

Consiglio³

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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RC-time delay in Cu interconnects is becoming a significant factor requiring further performance improvements in future nanoelectronic devices. Choice of alternate interconnect materials, as for example, refractory metals, and subsequent integration with underlying barrier and liner layers are extremely challenging for the sub-10 nm nodes. The development of conformal deposition processes for alternate interconnects, liner, and barrier materials are crucial in order for implementation of a possible replacement for Cu interconnects for narrow line widths. In this study we report on ultra-thin (~ 3nm) chemical 2 vapor deposition (CVD) grown ruthenium films on 0.5 and 1 nm thick metal nitride (TiN, TaN) barrier layers deposited via atomic layer deposition (ALD). Using scanning electron microscopy, we determined the effect of the underlying barrier layer on the coverage of the ruthenium overlayer. We utilized synchrotron x-ray diffraction with in-situ rapid thermal annealing to investigate the thermal stability of the barrier layers and determine the effective activation energies of barrier failure leading to ruthenium monosilicide formation.For Ru films deposited directly on Si and on 0.5 nm MN (M=Ti, Ta) covered Si substrates, silicide formation proceeds via a two-step crystallization process involving lateral nucleation above ~ 440 °C followed by thickening of the ruthenium monosilicide layer above ~520 °C. This silicidation temperature of ~ 440 °C could be potentially problematic in back-end-of-the-line (BEOL) processing since it is close to the typical thermal budget used. However ~1 nm thick ALD MN (M=Ti, Ta) was found to be adequate to block silicide formation up to ~ 580 °C and ~ 620 °C for TiN and TaN, respectively, and also aided in superior coverage of the CVD ruthenium overlayer (>90%). The results reported here might be useful to ascertain annealing temperature and time for BEOL process and integration optimization without reaching a state where ruthenium silicides start forming.

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Integration of ALD barrier and CVD Ru liner for void free PVD Cu reflow process on sub-10nm node technologies

Cited by 7 publications

References 3 publications

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects

State of the Art and Future Perspectives in Advanced CMOS Technology

Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications

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Integration of ALD barrier and CVD Ru liner for void free PVD Cu reflow process on sub-10nm node technologies

Cited by 7 publications

References 3 publications

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta1-XAlXNy Films for Cu Diffusion Barrier Applications in Advanced Interconnects

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta1-XAlXNy Films for Cu Diffusion Barrier Applications in Advanced Interconnects

State of the Art and Future Perspectives in Advanced CMOS Technology

Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications

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Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects

Atomic Layer Deposition of Ultrathin TaN and Ternary Ta_1-XAl_XN_y Films for Cu Diffusion Barrier Applications in Advanced Interconnects