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Title: The annealing effects on the micro-structure and properties of RuMoC films as seedless barrier for advanced Cu metallization

Abstract

100 nm thick RuMoC films and 5 nm thick RuMoC films with Cu capping have been deposited on Si(111) by magnetron co-sputtering with Ru and MoC confocal targets. The samples were subsequently annealed at temperatures ranging from 450 to 650 °C in vacuum at a pressure of 3 × 10{sup −4} Pa to study the annealing effects on the microstructures and properties of RuMoC films for advanced seedless Cu metallization applications. The sheet resistances, residual oxygen contents, and microstructures of the RuMoC films have close correlation with the doping contents of Mo and C, which can be easily controlled by the deposition power ratio of MoC versus Ru targets (DPR). When DPR was 0.5, amorphous RuMoC film (marked as RuMoC II) with low sheet resistances and residual oxygen contents was obtained. The fundamental relationship between the annealing temperatures with the microstructures and properties of the RuMoC films was investigated, and a critical temperature point was revealed at about 550 °C where the components and microstructures of the RuMoC II films changed obviously. Results indicated that below 550 °C, the RuMoC II films remained amorphous due to the well-preserved C-Ru and C-Mo bonds. However, above 550 °C, the microstructures of RuMoC II films transformed from amorphous to nano-composite structuremore » due to the breakage of Ru-C bonds, while the supersaturated solid solution MoC segregated out along the grain boundaries of Ru, thus hindering the diffusion of Cu and O atoms. This is the main mechanism of the excellent thermal stability of the RuMoC films after annealing at high temperatures. The results indicated great prospects of amorphous RuMoC films in advanced seedless Cu metallization applications.« less

Authors:
;  [1]; ; ;  [2];  [3];  [4]
  1. Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China)
  2. Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences, Shenzhen 518055 (China)
  3. (China)
  4. Institut d'Electronique Fondamentale, CNRS-Université Paris Sud UMR 8622, 91405 Orsay (France)
Publication Date:
OSTI Identifier:
22598817
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 9; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; ATOMS; CARBON; COPPER; CRITICAL TEMPERATURE; FILMS; GRAIN BOUNDARIES; MAGNETRONS; MOLYBDENUM; MOLYBDENUM CARBIDES; OXYGEN; RUTHENIUM; SHEETS; SOLID SOLUTIONS; SPUTTERING; TEMPERATURE RANGE 0400-1000 K

Citation Formats

Zou, Jianxiong, Liu, Bo, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Jiao, Guohua, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Lu, Yuanfu, Dong, Yuming, The Chinese University of Hong Kong, Hong Kong, and Li, Qiran. The annealing effects on the micro-structure and properties of RuMoC films as seedless barrier for advanced Cu metallization. United States: N. p., 2016. Web. doi:10.1063/1.4962011.
Zou, Jianxiong, Liu, Bo, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Jiao, Guohua, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Lu, Yuanfu, Dong, Yuming, The Chinese University of Hong Kong, Hong Kong, & Li, Qiran. The annealing effects on the micro-structure and properties of RuMoC films as seedless barrier for advanced Cu metallization. United States. doi:10.1063/1.4962011.
Zou, Jianxiong, Liu, Bo, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Jiao, Guohua, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn, Lu, Yuanfu, Dong, Yuming, The Chinese University of Hong Kong, Hong Kong, and Li, Qiran. 2016. "The annealing effects on the micro-structure and properties of RuMoC films as seedless barrier for advanced Cu metallization". United States. doi:10.1063/1.4962011.
@article{osti_22598817,
title = {The annealing effects on the micro-structure and properties of RuMoC films as seedless barrier for advanced Cu metallization},
author = {Zou, Jianxiong and Liu, Bo, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn and Jiao, Guohua, E-mail: liubo2009@scu.edu.cn, E-mail: gh.jiao@siat.ac.cn and Lu, Yuanfu and Dong, Yuming and The Chinese University of Hong Kong, Hong Kong and Li, Qiran},
abstractNote = {100 nm thick RuMoC films and 5 nm thick RuMoC films with Cu capping have been deposited on Si(111) by magnetron co-sputtering with Ru and MoC confocal targets. The samples were subsequently annealed at temperatures ranging from 450 to 650 °C in vacuum at a pressure of 3 × 10{sup −4} Pa to study the annealing effects on the microstructures and properties of RuMoC films for advanced seedless Cu metallization applications. The sheet resistances, residual oxygen contents, and microstructures of the RuMoC films have close correlation with the doping contents of Mo and C, which can be easily controlled by the deposition power ratio of MoC versus Ru targets (DPR). When DPR was 0.5, amorphous RuMoC film (marked as RuMoC II) with low sheet resistances and residual oxygen contents was obtained. The fundamental relationship between the annealing temperatures with the microstructures and properties of the RuMoC films was investigated, and a critical temperature point was revealed at about 550 °C where the components and microstructures of the RuMoC II films changed obviously. Results indicated that below 550 °C, the RuMoC II films remained amorphous due to the well-preserved C-Ru and C-Mo bonds. However, above 550 °C, the microstructures of RuMoC II films transformed from amorphous to nano-composite structure due to the breakage of Ru-C bonds, while the supersaturated solid solution MoC segregated out along the grain boundaries of Ru, thus hindering the diffusion of Cu and O atoms. This is the main mechanism of the excellent thermal stability of the RuMoC films after annealing at high temperatures. The results indicated great prospects of amorphous RuMoC films in advanced seedless Cu metallization applications.},
doi = {10.1063/1.4962011},
journal = {Journal of Applied Physics},
number = 9,
volume = 120,
place = {United States},
year = 2016,
month = 9
}
  • A novel plasma-enhanced atomic layer deposition-grown mixed-phase/nanolaminate Ru-TaN barrier has been investigated, and it was confirmed that the copper diffusion barrier and direct-plate characteristics of the mixed-phase barrier can be modulated by varying the metal ratio in the film. This liner was subsequently optimized to yield a composition that combines the robust barrier properties of TaN with direct-plate characteristics of Ru. It was found that the deposited multicomponent system consists of individual crystalline and amorphous phase regions distributed across the barrier. The resulting optimized mixed-phase barrier was found to exhibit excellent copper diffusion barrier characteristics in layers as thin asmore » 2 nm. A high degree of (111) texture (>84%) was observed for the direct-plated copper on this Ru-TaN barrier, which was very similar to the electroplated Cu deposited on a physical vapor deposition copper-seed control sample. Additionally, the filling characteristics in sub-50-nm features were found to be equivalent to those of conventionally copper-seeded interconnect structures.« less
  • The nucleation and growth of WN{sub x}C{sub y} films deposited by atomic layer deposition (ALD) on plasma enhanced chemical vapor deposited (PECVD) SiO{sub 2} is characterized as a function of the number of ALD cycles using transmission electron microscopy analysis. The island growth of isolated WN{sub x}C{sub y} nanocrystals is directly observed at the early stages of film growth. The nucleation of the WN{sub x}C{sub y} film can be significantly enhanced by NH{sub 3} plasma treatment before the deposition of WN{sub x}C{sub y}. The capacitance-voltage measurements conducted after bias-temperature stressing reveals that an ALD-WN{sub x}C{sub y} film deposited with amore » thickness of approximately 5.2 nm on the NH{sub 3} plasma-treated PECVD SiO{sub 2} shows good diffusion barrier performance against Cu migration.« less
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  • Tungsten carbides (WC{sub x}) thin films were deposited on thermally grown SiO{sub 2} substrates by atomic layer deposition (ALD) using a fluorine- and nitrogen-free W metallorganic precursor, tungsten tris(3-hexyne) carbonyl [W(CO)(CH{sub 3}CH{sub 2}C ≡ CCH{sub 2}CH{sub 3}){sub 3}], and N{sub 2} + H{sub 2} plasma as the reactant at deposition temperatures between 150 and 350 °C. The present ALD-WC{sub x} system showed an ALD temperature window between 200 and 250 °C, where the growth rate was independent of the deposition temperature. Typical ALD characteristics, such as self-limited film growth and a linear dependency of the film grown on the number of ALD cycles, were observed, withmore » a growth rate of 0.052 nm/cycle at a deposition temperature of 250 °C. The ALD-WC{sub x} films formed a nanocrystalline structure with grains, ∼2 nm in size, which consisted of hexagonal W{sub 2}C, WC, and nonstoichiometric cubic β-WC{sub 1−x} phase. Under typical deposition conditions at 250 °C, an ALD-WC{sub x} film with a resistivity of ∼510 μΩ cm was deposited and the resistivity of the ALD-WC{sub x} film could be reduced even further to ∼285 μΩ cm by further optimizing the reactant pulsing conditions, such as the plasma power. The step coverage of ALD-WC{sub x} film was ∼80% on very small sized and dual trenched structures (bottom width of 15 nm and aspect ratio of ∼6.3). From ultraviolet photoelectron spectroscopy, the work function of the ALD-WC{sub x} film was determined to be 4.63 eV. Finally, the ultrathin (∼5 nm) ALD-WC{sub x} film blocked the diffusion of Cu, even up to 600 °C, which makes it a promising a diffusion barrier material for Cu interconnects.« less
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