Diffusion barrier performance of novel Ti/TaN double layers for Cu metallization

Zhou, Yan; He, Meng-Dong; Xie, Zhong

doi:10.1016/j.apsusc.2014.07.146

Cited by 17 publications

(7 citation statements)

References 23 publications

(31 reference statements)

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“…After annealing the Cu/TiN bilayer at 700 °C, additional diffraction peaks appear at 2θ = 28.0, 35.2, 42.4, 44.6, 45.0, 58.0, and 65.2° arising from the appearance of the orthorhombic η ″-Cu 3 Si phase 26 . This compound is often reported as a reaction product due to Cu and Si interdiffusion through barrier layers in Cu/barrier/Si(001) stacks 27 , and therefore serves as a qualitative benchmark in evaluating barrier performance 1 , 3 , 4 , 27 . Formation of Cu 3 Si occurs locally at the barrier/Si interface 1 , 28 , 29 , and the 150% volume expansion 30 compared to Si results in the formation of hillocks as observed in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Diffusion barriers are vital components in integrated circuits (ICs), designed to impede interdiffusion between Cu metallization and doped Si layers 1 , 2 . Barrier failure leading to in-diffusion of Cu results in the formation of Cu silicides, which severely impair device performance and lifetime 1 , 3 , 4 . Since diffusion is a thermally-activated process, efficient diffusion barrier layers require a thermally-stable microstructure, with an electrical conductivity similar to that of Cu (1.74 µΩ-cm for bulk Cu, 2.0 µΩ-cm for a 1.5-µm-thick polycrystalline Cu film) 5 , 6 in order to optimize device functionality 7 .…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Ti0.84Ta0.16N diffusion barriers, grown by a hybrid sputtering technique with no substrate heating, between Si(001) wafers and Cu overlayers

Mühlbacher

Greczyński

Sartory

et al. 2018

Sci Rep

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We compare the performance of conventional DC magnetron sputter-deposited (DCMS) TiN diffusion barriers between Cu overlayers and Si(001) substrates with Ti0.84Ta0.16N barriers grown by hybrid DCMS/high-power impulse magnetron sputtering (HiPIMS) with substrate bias synchronized to the metal-rich portion of each pulse. DCMS power is applied to a Ti target, and HiPIMS applied to Ta. No external substrate heating is used in either the DCMS or hybrid DCMS/HiPIMS process in order to meet future industrial thermal-budget requirements. Barrier efficiency in inhibiting Cu diffusion into Si(001) while annealing for 1 hour at temperatures between 700 and 900 °C is investigated using scanning electron microscopy, X-ray diffraction, four-point-probe sheet resistance measurements, transmission electron microscopy, and energy-dispersive X-ray spectroscopy profiling. Ti0.84Ta0.16N barriers are shown to prevent large-scale Cu diffusion at temperatures up to 900 °C, while conventional TiN barriers fail at ≤700 °C. The improved performance of the Ti0.84Ta0.16N barrier is due to film densification resulting from HiPIMS pulsed irradiation of the growing film with synchronized Ta ions. The heavy ion bombardment dynamically enhances near-surface atomic mixing during barrier-layer deposition.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced Ti0.84Ta0.16N diffusion barriers, grown by a hybrid sputtering technique with no substrate heating, between Si(001) wafers and Cu overlayers

Mühlbacher

Greczyński

Sartory

et al. 2018

Sci Rep

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“…1,2 The nitrogen content in TaN thin films affects the diffusion barrier performance and the sheet resistance of the thin film, which has a noticeable impact on the RC delay. 3,4 Furthermore, it influences the crystallinity of the Ta layer deposited on top of it. Several publications describe a change from high resistive tetragonal β-Ta to low resistive body-centered cubic α-Ta with increasing nitrogen content in the TaN interlayer.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the composition of tantalum nitride in CMOS metallization trenches using parallel angle‐resolved XPS

Wehring

Gerlich

Kia

et al. 2020

Surface & Interface Analysis

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We demonstrate the utilization of parallel angle-resolved X-ray photoelectron spectroscopy (pAR-XPS) as a useful tool to analyze ultrathin sputtered tantalum nitride (TaN) thin films in complementary metal-oxide-semiconductor (CMOS) trenches. The chemical composition of TaN was estimated by pAR-XPS using a Theta 300i from Thermo Fischer. An improved lateral resolution was achieved by analyzing periodic structures. The XPS data was correlated with transmission electron microscopy (TEM) in combination with energy-dispersive X-ray spectroscopy (EDX) and time-offlight secondary ion mass spectrometry (ToF-SIMS) data. The results show that the nitrogen content in the TaN thin films was about 6% higher at the sidewall compared with the top and bottom of the trench.

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“…The barriers therefore are needed to confine Cu wires. Traditionally, the used metal barriers are Ti(N), Ta(N), or Ru(N) with a relatively high resistivity compared to Cu, thereby increasing line resistance for Cu metallization [16,17]. This situation is getting worse with scaling of BEOL interconnects because a large fraction of the line-width is occupied by the metal barrier.…”

Section: Introductionmentioning

confidence: 99%

Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment

et al. 2019

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Highly porous low-dielectric-constant (low-k) dielectric materials with a dielectric constant (k) less than 2.50 are needed for 32 nm and beyond technological nodes. In this study, a highly porous low-k dielectric film with a k value of 2.25, open porosity of 32.0%, and pore diameter of 1.15 nm were treated by 3-Aminopropyltrimethoxysilane (APTMS) in wet solution in order to form self-assembled monolayers (SAMs) onto it. The effects of the formation SAMs on the electrical characteristics and reliability of highly porous low-k dielectric films were characterized. As SAMs were formed onto the highly porous low-k dielectric film by APTMS treatment, the dielectric breakdown field and the failure time were significantly improved, but at the expense of the increases in the dielectric constant and leakage current. Moreover, the formation SAMs enhanced the Cu barrier performance for highly porous low-k dielectric films. Therefore, the SAMs derived from APTMS treatment are promising for highly porous low-k dielectric films to ensure better integrity.

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Diffusion barrier performance of novel Ti/TaN double layers for Cu metallization

Cited by 17 publications

References 23 publications

Enhanced Ti0.84Ta0.16N diffusion barriers, grown by a hybrid sputtering technique with no substrate heating, between Si(001) wafers and Cu overlayers

Enhanced Ti0.84Ta0.16N diffusion barriers, grown by a hybrid sputtering technique with no substrate heating, between Si(001) wafers and Cu overlayers

Analysis of the composition of tantalum nitride in CMOS metallization trenches using parallel angle‐resolved XPS

Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment

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