Structure–Diffusion Relationship of Magnetron-Sputtered WTi Barriers Used in Indium Interconnections

Priol, A. Le; Bourhis, E. Le; Renault, P.-O.; Müller, Pierre; Sik, H.

doi:10.1007/s11664-013-2843-1

Cited by 3 publications

(6 citation statements)

References 26 publications

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“…Two metallic layers; Ti

_{10}

_{90}

and Ta, can be suitable as a diffusion barrier due to their thermal and chemical stability as well as their thermal expansion coefficient (CTE), which is close to CTE of Si (CTE: Si = 2.6–3.3 ppm K

^{- 1}

, Ta = 6.5 ppm K

^{- 1}

(), and Ti

_{10}

_{90}

= 4.5–8.6 ppm K

^{- 1}

()). Intentionally, a barrier could be deposited thick enough in order to block the diffusing atoms from a top layer in reaching the substrate.…”

Section: Barrier Stress Adjustmentmentioning

confidence: 99%

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Budhiman

Schürmann

Jensen

et al. 2015

Phys. Status Solidi A

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Transmission electron microscopy (TEM) analysis, including energy dispersive X-ray (EDX) (elemental mapping, line, and point measurements) and energy filtered TEM (EFTEM) methods, is applied to investigate the high temperature reliability, especially material diffusion, of two types of diffusion barriers: titanium-tungsten-based (Ti10W90-based) and tantalum-based (Ta-based), with nickel (Ni) layer on top. Both barriers were deposited as a form of stacked layers on sili-con (Si) wafers using the physical vapor deposition (PVD) technique. TEM analysis is performed on both barriers before and after annealing (at 600degC for 24h inside a vacuum chamber). No diffusion of material into the Si substrate as observed. Additionally, only diffusion between the Ni and adjoining Ti10W90 layers, and between Ni and adjoining Ta layers in the Ti10W90-based and Ta-based barriers, respectively, are observed due to annealing

show abstract

“…Two metallic layers; Ti

_{10}

_{90}

and Ta, can be suitable as a diffusion barrier due to their thermal and chemical stability as well as their thermal expansion coefficient (CTE), which is close to CTE of Si (CTE: Si = 2.6–3.3 ppm K

^{- 1}

, Ta = 6.5 ppm K

^{- 1}

(), and Ti

_{10}

_{90}

= 4.5–8.6 ppm K

^{- 1}

()). Intentionally, a barrier could be deposited thick enough in order to block the diffusing atoms from a top layer in reaching the substrate.…”

Section: Barrier Stress Adjustmentmentioning

confidence: 99%

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Budhiman

Schürmann

Jensen

et al. 2015

Phys. Status Solidi A

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“…TiW is compatible with various metallisations (Al, Au, Ag, In and Cu) and has remarkable thermal stability at elevated temperatures (≤850 • C). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Consequently, TiW diffusion barriers are now being widely implemented in next-generation SiC-based power semiconductor technologies with copper metallisation schemes, [20][21][22] and more recently within electrodes for GaAs photoconductive semiconductor switches (PCSSs), [23] and gate metal stacks in GaN-based high electron mobility transistor (HEMT) devices. [24] Diffusion barriers are needed as Cu and Si readily react at relatively low temperatures to form intermetallic copper-silicide compounds at the interface, which seriously hamper the performance and reliability of devices.…”

Section: Introductionmentioning

confidence: 99%

“…Le Priol et al studied the efficiency of a TiW barrier deposited from a 70:30 at.% W:Ti alloy target against indium diffusion at temperatures between 573-673 K under vacuum. [17] The authors could correlate the TiW barrier efficiency with its microstructure and determine the diffusion coefficient of In in TiW. Siol et al were interested in understanding the oxidation of TiW alloy precursors, and observed oxygen dissolution and the formation and decomposition of mixed (W,Ti)-oxide phases when ramping the temperature between 303 to 1073 K in air.…”

Section: Introductionmentioning

confidence: 99%

Capturing the dynamics of Ti diffusion across Ti$_x$W$_{1-x}$/Cu heterostructures using X-ray photoelectron spectroscopy

Kalha¹,

Thakur²,

Lee³

et al. 2023

Preprint

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Interdiffusion phenomena between adjacent materials are highly prevalent in semiconductor device architectures and can present a major reliability challenge for the industry. To fully capture these phenomena, experimental approaches must go beyond static and post-mortem studies to include in-situ and in-operando setups. Here, soft and hard X-ray photoelectron spectroscopy (SXPS and HAXPES) is used to monitor diffusion in real-time across a proxy device. The device consists of a Si/SiO2/TixW1−x(300 nm)/Cu(25 nm) thin film material stack, with the TixW1−x film acting as a diffusion barrier between Si and Cu. The diffusion is monitored through the continuous collection of spectra whilst in-situ annealing to 673 K. Ti within the TiW is found to be highly mobile during annealing, diffusing out of the barrier and accumulating at the Cu surface. Increasing the Ti concentration within the TixW1−x film increases the quantity of accumulated Ti, and Ti is first detected at the Cu surface at temperatures as low as 550 K. Surprisingly, at low Ti concentrations (x = 0.054), W is also mobile and diffuses alongside Ti. These results provide crucial evidence for the importance of diffusion barrier composition on their efficacy during device application, delivering insights into the mechanisms underlying their effectiveness and limitations.

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“…studied the efficiency of a TiW barrier deposited from a 70:30 at.% W:Ti alloy target against indium diffusion at temperatures between 573 and 673 K under vacuum. [ 17 ] The authors could correlate the TiW barrier efficiency with its microstructure and determine the diffusion coefficient of In in TiW. Siol et al.…”

Section: Introductionmentioning

confidence: 99%

“…TiW is compatible with various metallisations (Al, Au, Ag, In, and Cu) and has remarkable thermal stability at elevated temperatures (⩽850°C). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Consequently, TiW diffusion barriers are now being widely implemented in nextgeneration SiC-based power semiconductor technologies with copper metallisation schemes, [20][21][22] and more recently within electrodes for GaAs photoconductive semiconductor switches (PCSSs), [23] and gate metal stacks in GaN-based high electron mobility transistor (HEMT) devices. [24] Diffusion barriers are needed as Cu and Si readily react at relatively low temperatures to form intermetallic coppersilicide compounds at the interface.…”

Section: Introductionmentioning

confidence: 99%

Capturing the Dynamics of Ti Diffusion Across Ti_xW_1−x/Cu Heterostructures using X‐Ray Photoelectron Spectroscopy

Kalha

Thakur

Lee

et al. 2023

Advanced Physics Research

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Interdiffusion phenomena between adjacent materials are highly prevalent in semiconductor device architectures and can present a major reliability challenge for the industry. To fully capture these phenomena, experimental approaches must go beyond static and post‐mortem studies to include in situ and in‐operando setups. Here, soft and hard X‐ray photoelectron spectroscopy (SXPS and HAXPES) is used to monitor diffusion in real‐time across a proxy device. The device consists of a Si/SiO2/TixW1−x(300 nm)/Cu(25 nm) thin film material stack, with the TixW1−x film (x = 0.054, 0.115, 0.148) acting as a diffusion barrier between Si and Cu. The interdiffusion is monitored through the continuous collection of spectra whilst in situ annealing to 673 K. Ti within the TiW is found to be highly mobile during annealing, diffusing out of the barrier and accumulating at the Cu surface. Increasing the Ti concentration within the TixW1−x film increases the quantity of accumulated Ti, and Ti is first detected at the Cu surface at temperatures as low as 550 K. Surprisingly, at low Ti concentrations (x = 0.054), W is also mobile and diffuses alongside Ti. By monitoring the Ti 1s core level with HAXPES, the surface‐accumulated Ti was observed to undergo oxidation even under ultra‐high vacuum conditions, highlighting the reactivity of Ti in this system. These results provide crucial evidence for the importance of diffusion barrier composition on their efficacy during device application, delivering insights into the mechanisms underlying their effectiveness and limitations.

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Structure–Diffusion Relationship of Magnetron-Sputtered WTi Barriers Used in Indium Interconnections

Cited by 3 publications

References 26 publications

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Capturing the dynamics of Ti diffusion across Ti$_x$W$_{1-x}$/Cu heterostructures using X-ray photoelectron spectroscopy

Capturing the Dynamics of Ti Diffusion Across Ti_xW_1−x/Cu Heterostructures using X‐Ray Photoelectron Spectroscopy

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Structure–Diffusion Relationship of Magnetron-Sputtered WTi Barriers Used in Indium Interconnections

Cited by 3 publications

References 26 publications

Transmission electron microscopy study for investigating high-temperature reliability of Ti10 W90 -based and Ta-based diffusion barriers up to 600°C

Transmission electron microscopy study for investigating high-temperature reliability of Ti10 W90 -based and Ta-based diffusion barriers up to 600°C

Capturing the dynamics of Ti diffusion across Ti$_x$W$_{1-x}$/Cu heterostructures using X-ray photoelectron spectroscopy

Capturing the Dynamics of Ti Diffusion Across TixW1−x/Cu Heterostructures using X‐Ray Photoelectron Spectroscopy

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About

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Transmission electron microscopy study for investigating high-temperature reliability of Ti₁₀ W₉₀ -based and Ta-based diffusion barriers up to 600°C

Capturing the Dynamics of Ti Diffusion Across Ti_xW_1−x/Cu Heterostructures using X‐Ray Photoelectron Spectroscopy