Scalability of RuTiN barriers deposited by plasma-enhanced atomic layer deposition for advanced interconnects

Swerts, Johan; Siew, Yong-Kong; Besien, Els Van; Barbarin, Y.; Opsomer, Karl; Bömmels, J.; Tőkei, Zsolt; Elshocht, Sven Van

doi:10.1016/j.mee.2013.08.008

Cited by 4 publications

(3 citation statements)

References 16 publications

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“…Based on many studies of Ru ALD, it is clear that both the precursors and reaction conditions, in particular the reaction temperature, can strongly affect the nucleation and thin film growth. Our recent results on PEALD of Ru also illustrate this − (see Figure ). We observed a markedly different reactivity of the bis(ethylcyclopentadienyl)ruthenium (Ru(EtCp) 2 ) and (methylcyclopentadienylpyrrolyl)ruthenium (Ru(MeCp)Py) precursor.…”

Section: Introductionsupporting

confidence: 56%

“…The first and most widely studied and applied group of precursors consists of ruthenocenes and their derivatives, including RuCp 2 , Ru(EtCp) 2 , (MeCp)Ru(EtCp), (EtCp)Ru(DMPD), and Ru(DMPD) 2 , with Me = methyl, Cp = cyclopentadienyl, Et = ethyl, and DMPD = dimethylpentadienyl. By replacing one or both cyclopentadienyl rings with pyrrolyl (Py), pyrrolyl-based precursors are obtained, e.g., (MeCp)Ru(Py) − and Ru(Me 2 Py) 2 . The second group of precursors consists of β-diketonate precursors, e.g., Ru(thd) 3 and Ru(od) 3 .…”

Section: Introductionmentioning

confidence: 99%

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Atomic Layer Deposition of Ruthenium on Ruthenium Surfaces: A Theoretical Study

et al. 2015

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Atomic layer deposition (ALD) of ruthenium using two ruthenium precursors, i.e., Ru(C 5 H 5 ) 2 (RuCp 2 ) and Ru(C 5 H 5 )(C 4 H 4 N) (RuCpPy), is studied using density functional theory. By investigating the reaction mechanisms on bare ruthenium surfaces, i.e., (001), (101), and (100), and H-terminated surfaces, an atomistic insight in the Ru ALD is provided. The calculated results show that on the Ru surfaces both RuCp 2 and RuCpPy can undergo dehydrogenation and ligand dissociation reactions. RuCpPy is more reactive than RuCp 2 . By forming a strong bond between N of Py and Ru of the surface, RuCpPy can easily chemisorb on the surfaces. The reactions of RuCp 2 on the surfaces are less favorable as the adsorption is not strong enough. This could be a factor contributing to the higher growth-per-cycle of Ru using RuCpPy, as observed experimentally. By studying the adsorption on H-terminated Ru surfaces, we showed that H can prevent the adsorption of the precursors, thus inhibiting the growth of Ru. Our calculations indicate that the H content on the surface can have an impact on the growth-percycle. Finally, our simulations also demonstrate large impacts of the surface structure on the reaction mechanisms. Of the three surfaces, the (100) surface, which is the less stable and has a zigzag surface structure, is also the most reactive one.

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Section: Introductionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Ruthenium on Ruthenium Surfaces: A Theoretical Study

et al. 2015

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“…Recently, Amanapu et al 15 showed that Ru films deposited on TiN, another commonly used barrier layer 16,17 with a lower resistivity of ∼130 μ cm, have higher removal rates (RRs) compared to those deposited on TaN due to the difference in the crystalline orientation of the Ru films deposited on these two materials. Hence, a thin Ru liner (∼2 nm) over a thin TiN barrier layer (∼2 nm), both deposited by ALD, has been proposed as a promising barrier liner for future Cu interconnects.…”

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confidence: 99%

Potassium Permanganate-Based Slurry to Reduce the Galvanic Corrosion of the Cu/Ru/TiN Barrier Liner Stack during CMP in the BEOL Interconnects

Sagi

Amanapu

Alety

et al. 2016

ECS J. Solid State Sci. Technol.

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Chemical mechanical polishing (CMP) behavior of Cu/Ru/TiN barrier liner stack was investigated with a slurry comprising of silica abrasives, potassium permanganate (KMnO 4 ) , guanidine carbonate (GC) and benzotriazole (BTA) in the alkaline region. The corrosion and polishing behavior of the Cu, Ru and TiN films in the solution consisting of the above additives were characterized by open circuit potential and potentiodynamic measurements, polishing rates, dissolution rates and contact angle measurements. A slurry comprising of 10 mM KMnO 4 , 1 wt% GC and 5 wt% Silica at pH 10 has shown adequate polish rates as well as low individual film corrosion. However, 1 mM BTA was needed to maintain the E CORR of both the Cu/Ru and Ru/TiN couples at <20 mV essential to inhibit any galvanic corrosion while still maintaining low corrosion rates for Cu, Ru and TiN films. The removal rate ratio of Ru:Cu with the optimized slurry was ∼0.8, minimizing the possibility of dishing. As the scaling of trenches and vias continue, making high volume manufacturing of 14 nm devices feasible, deposition of defect free Cu seed layer upon the TaN/Ta barrier liner 1,2 used in earlier generation Cu interconnects has become a challenge. At the reduced trench widths of ∼50 nm or less associated with these devices, it is not possible to deposit a conformal Cu seed layer without voids.3-6 Also, as the TaN/Ta barrier liner is scaled to ∼5 nm or less in thickness, its increased electrical resistance causes the resistance-capacitance delay to increase. Hence, the advantages of replacing it with several other barrier and barrier liner candidate materials and have been investigated by various authors.7-9 These include Ru, Co and Mn and their alloys.Among these, Ru has good barrier properties with a high melting point of 2310• C. 7 Due to its low resistivity (∼7 μ cm) and excellent wettability characteristics with Cu, direct electroplating of Cu is possible eliminating the need for a seed layer.7 However, it was found that atomic layer deposited (ALD) Ru alone is not a good diffusion barrier due to its columnar growth structure that provides diffusion paths for Cu at the grain boundaries 10,11 and poor adherence to underlying dielectric.12 Hence, it was proposed that a thin TaN barrier layer (∼2-3 nm) be first deposited followed by a ∼1-2 nm thick Ru liner, alleviating the need for a Cu seed layer. 13,14 However, the higher resistivity of TaN (∼200 μ cm) is still a concern.Recently, Amanapu et al. 15 showed that Ru films deposited on TiN, another commonly used barrier layer 16,17 with a lower resistivity of ∼130 μ cm, have higher removal rates (RRs) compared to those deposited on TaN due to the difference in the crystalline orientation of the Ru films deposited on these two materials. Hence, a thin Ru liner (∼2 nm) over a thin TiN barrier layer (∼2 nm), both deposited by ALD, has been proposed as a promising barrier liner for future Cu interconnects.In these structures, since Ru is in contact with both TiN and Cu (Figure 1), there is a possibility of g...

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Advanced characterizations of fluorine-free tungsten film and its application as low resistance liner for PCRAM

Rodriguez

Famulok

Friec

et al. 2017

Materials Science in Semiconductor Processing

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International audienceUsing a metal-organic tungsten based precursor, a fluorine-free tungsten thin film has been obtained. The process deposition recipe includes a plasma-enhanced CVD (PECVD) step and atomic layer deposition (ALD) cycles. A set of physicochemical characterizations including X-ray reflectivity (XRR), in-plane X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), plasma profiling time of flight mass spectrometry (PPTOFMS) and microscope observations has been realized in order to study the W thin film structure and properties. The film is perfectly conformal whatever the structure size investigated (from tens of nanometers to micrometers wide). It was also highlighted that the F-free W film exhibits the lowest electrical resistivity phase (α-W) but is not pure. Indeed, in addition to a top surface oxidation, a layer located at the W film / substrate interface is present. This interface layer (IL) contains impurities, including carbon and oxygen, due to ligand decomposition. This IL might be deposited during the soak step or during the PECVD step. The W liner with thicknesses ranging from 3 to 4 nm has been implemented on PCRAM structures in order to evaluate its impact on contact plug resistivity. First electrical results are promising and demonstrate the interest of using a F-free low resistance W liner. At the aspect ratio studied, the gain in terms of contact plug resistivity is about 20% compared to the process of reference using a TiN liner. Modeling shows that this benefit is mainly due to the reduction of interface resistances

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Scalability of RuTiN barriers deposited by plasma-enhanced atomic layer deposition for advanced interconnects

Cited by 4 publications

References 16 publications

Atomic Layer Deposition of Ruthenium on Ruthenium Surfaces: A Theoretical Study

Atomic Layer Deposition of Ruthenium on Ruthenium Surfaces: A Theoretical Study

Potassium Permanganate-Based Slurry to Reduce the Galvanic Corrosion of the Cu/Ru/TiN Barrier Liner Stack during CMP in the BEOL Interconnects

Advanced characterizations of fluorine-free tungsten film and its application as low resistance liner for PCRAM

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