Effects of N doping in Ru-Ta alloy barrier on film property and reliability for Cu interconnects

Torazawa, Naoki; Hinomura, Toru; Mori, Kohsuke; Koyama, Yuki; Hirao, S.; Kobori, Etsuyoshi; Korogi, Hayato; Maekawa, Kazuyoshi; Tomita, Kazuo; Chibahara, Hiroyuki; Suzumura, N.; Asai, Koyu; Miyatake, Hiroshi; Matsumoto, Susumu

doi:10.1109/iitc.2009.5090356

Cited by 4 publications

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“…Fabrication of self-formed barrier metal using manganese (Mn) or titanium (Ti) deposited with physical vapor deposition (PVD) and tantalum (Ta) or ruthenium (Ru) deposited with atomic layer deposition has been reported recently. [15][16][17] Ru is a promising alternative owing to its high wettability with Cu. 18) PVD-Ru barrier is advantageous because it is available only by replacing the conventional Ta targets in standard sputtering apparatus.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of 70-nm-Pitch Two-Level Interconnects by using Extreme Ultraviolet Lithography

Nakamura¹,

Oda²,

Soda³

et al. 2011

Jpn. J. Appl. Phys.

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We investigate the emissions of atomic potassium excited by two photons near the 4S 1/2 -6S 1/2 transition. Radiation near the 6S 1/2 -4P 3/2,1/2 and 4P 3/2,1/2 -4S 1/2 transitions are studied for the unidirectional and the bidirectional cases, respectively. It is shown that the total output intensity increases considerably for the bidirectional propagation. This is attributed to the effective increase of the Doppler free excitation and the cancellation of the quantum interference effect that is associated with the multiple paths of excitation of certain states.

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Section: Introductionmentioning

confidence: 99%

Fabrication of 70-nm-Pitch Two-Level Interconnects by using Extreme Ultraviolet Lithography

Nakamura¹,

Oda²,

Soda³

et al. 2011

Jpn. J. Appl. Phys.

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“…Despite the fact that RuTa and/or Ru-TaN have been reported to improve the barrier performance for Cu metallization, Ru-TaN has also been demonstrated to have barrier properties inferior to RuTa because of nitrogen desorption at elevated temperatures. 12 The desorption of nitrogen in Ru-TaN films indicates that nitrogen forms a weak bond with RuTa, especially when Ru-TaN is prepared by sputtering. Although TaC is also a good diffusion barrier ͑the failure temperature of 7-nm-thick TaC is 600°C͒, 13,14 the resistivity of TaC ͑210-1700 ⍀ cm͒ ͑Ref.…”

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confidence: 99%

Ultrathin Ru–Ta–C Barriers for Cu Metallization

Fang

Lin

Chen

et al. 2011

J. Electrochem. Soc.

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The use of an ultrathin Ru-Ta-C film as a barrier for copper metallization in sub-32-nm ultra-large-scale integration ͑ULSI͒ has been evaluated. The films, fixed at 5 nm, were deposited by magnetron sputtering using Ru and TaC targets, and the film composition and structure were adjusted by tuning the respective deposition power. The structure of the Ru-Ta-C films gradually changed from Ru 4 Ta͑C͒ to nanocrystalline or nearly amorphous when optimizing TaC. For a sandwiched scheme of Cu/Ru 82 Ta 12 C 5 /Si or Cu/Ru 77 Ta 15 C 7 /Si, the failure temperature was at least 750°C. We also electroplated Cu directly onto a Ru-Ta-C film without Cu seeding. Because of their low resistivity ͑ Ͻ 100 ⍀ cm͒ and high thermal stability, Ru-Ta-C films are promising as a Cu barrier.

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“…Several recent studies demonstrated that nitrided Ru barriers prepared by PVD had satisfactory barrier characteristics. [11][12][13][14] However, RuN x has a relatively high electrical resistance, making direct Cu electrodeposition difficult on the RuN x surface. In this study, we deposited Ru/RuN x bilayer barriers on mesoporous SiO 2 (thereafter denoted by mp-SiO 2 ) dielectric layers by an in situ two-step plasma-enhanced ALD (PEALD) process, and copper could be directly electrodeposited on the as-deposited Ru/RuN x barrier.…”

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confidence: 99%

In Situ Two-Step Plasma Enhanced Atomic Layer Deposition of Ru/RuNx Barriers for Seedless Copper Electroplating

Chang¹,

Pan²

2011

J. Electrochem. Soc.

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The study prepared Ru/RuN x bilayer barriers on mesoporous SiO 2 (mp-SiO 2 ) dielectric layers for direct Cu electroplating applications using in situ two-step plasma-enhanced atomic chemical vapor deposition (PEALD). For the 5 nm thick Ru/RuN x bilayer deposited at 200 C, obvious thermal decomposition begins at temperatures lower than 400 C. Copper can be successfully electroplated on the as-deposited Ru/RuN x bilayer, and the Cu/Ru/RuN x /mp-SiO 2 film stack can withstand thermal treatment at temperatures up to 500 C without significant physical and chemical degradations according to TEM and SIMS analyses. The study shows that the electroplated Cu layer behaves like a passivation layer that improves the thermal stability of the Ru/RuN x barrier during the thermal annealing. Pull-off tensile test shows that interfaces in the Cu/Ru/RuN x /mp-SiO 2 film stack have good adhesion strength, but delamination occurs at the interface between the Ru/RuN x bilayer and the mp-SiO 2 layer at 600 C, resulting in Cu and Ru diffusion into the dielectric layer. The study has demonstrated that the PEALD Ru/RuN x bilayer structure prepared using the in situ two-step approach is suitable for the seedless Cu electroplating process in nanometer scale interconnect technology.

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Effects of N doping in Ru-Ta alloy barrier on film property and reliability for Cu interconnects

Cited by 4 publications

References 0 publications

Fabrication of 70-nm-Pitch Two-Level Interconnects by using Extreme Ultraviolet Lithography

Fabrication of 70-nm-Pitch Two-Level Interconnects by using Extreme Ultraviolet Lithography

Ultrathin Ru–Ta–C Barriers for Cu Metallization

In Situ Two-Step Plasma Enhanced Atomic Layer Deposition of Ru/RuNx Barriers for Seedless Copper Electroplating

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