Evaluation of Ta and TaN-based Cu diffusion barriers deposited by Advanced Hi-Fill (AHF) sputtering onto blanket wafers and high aspect ratio structures

Burgess, Steve; Donohue, H.; Buchanan, Keith; Rimmer, N.; Rich, Phoebe

doi:10.1016/s0167-9317(02)00803-1

Cited by 13 publications

(6 citation statements)

References 4 publications

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“…Investigations concerning the influence of the N content on the diffusion barrier properties of TaN x films between copper and silicon show that the thermal stability increases with an increasing x N /x Ta ratio [31,92,118,119]. Based on X-ray diffraction experiments, Wang et al [92] detected the formation of Ta silicide and Cu silicide for 25 nm thick Ta and TaN barriers after annealing at T = 650 °C and 800 °C, respectively.…”

Section: Tan X Diffusion Barriersmentioning

confidence: 99%

Diffusion Barriers

Hecker¹,

Hübner²

2012

Advanced Interconnects for ULSI Technology

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Section: Tan X Diffusion Barriersmentioning

confidence: 99%

Diffusion Barriers

Hecker¹,

Hübner²

2012

Advanced Interconnects for ULSI Technology

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“…The layer is typically deposited by physical vapor deposition (PVD), which can result in a poor sidewall coverage and elemental composition differences over the trench. 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.…”

Section: Introductionmentioning

confidence: 99%

“…Current industry standard uses a tantalum nitride (TaN)/tantalum (Ta) bilayer as barrier layer. The layer is typically deposited by physical vapor deposition (PVD), which can result in a poor sidewall coverage and elemental composition differences over the trench 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 .…”

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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“…1 To fulfill a high thermal stability, sputtered refractory metals and their metallic compounds, such as Ta/TaN, 2,3 Ta-Si(N), 4 Ta-C, 5 W, Cr, Ti, and Mo intermetallic compounds, [6][7][8][9][10] are frequently adopted as Cu diffusion barriers, although refractory metal polycrystalline thin films are usually used as a barrier layer to prevent Cu diffusion. Sputtered thin films frequently have a columnar grain structure; however, their grain boundaries tend to serve as the expedient diffusion paths for copper atoms to penetrate the diffusion barrier easily, causing the reaction of silicon/copper interfaces by forming Cu 3 Si phase or generating deep-level recombination centers in dielectrics. In addition to the needs of high conductivity and thermal stability, therefore, diffusion barrier layers with an amorphous structure are more promising due to the microstructural freedom of the grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and failure behavior of Ta-TM (TM=Fe, Co) nanostructured/amorphous diffusion barriers for copper metallization

Fang

Hsu

Chen

2006

Journal of Elec Materi

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This work examined the thin-film properties and diffusion barrier behavior of sputtered Ta-TM (TM ‫ס‬ Fe, Co) films, aiming at depositing a highly crystallization-resistant and conductive diffusion barrier film for Cu metallization. Four-point probe measurement, x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a secondary ion mass spectrometer (SIMS) were used to examine the barrier properties. Structural examination indicated that intermetallic-compound-free amorphous Ta-TM films were obtained by magnetron sputtering, thus giving a resistivity of 146.82 ⍀-cm and 247.01 ⍀-cm for Ta 0.5 Fe 0.5 and Ta 0.5 Co 0.5 films, respectively. The Si/Ta 0.5 Fe 0.5 /Cu and Si/Ta 0.5 Co 0.5 /Cu stacked samples were observed to fail completely at temperature above 650°C and 700°C because of the formation of Cu 3 Si protrusions between silicon and the Ta-TM interface. Ta 0.5 Co 0.5 is thus superior to Ta 0.5 Fe 0.5 in preventing copper from diffusion. Highly thermally stabilized amorphous Ta-TM thin film can thus be potentially adopted as a diffusion barrier for Cu metallization.

show abstract

Evaluation of Ta and TaN-based Cu diffusion barriers deposited by Advanced Hi-Fill (AHF) sputtering onto blanket wafers and high aspect ratio structures

Cited by 13 publications

References 4 publications

Diffusion Barriers

Diffusion Barriers

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

Crystallization and failure behavior of Ta-TM (TM=Fe, Co) nanostructured/amorphous diffusion barriers for copper metallization

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