Deposition of titanium nitride/tungsten layers for application in vertically integrated circuits technology

Ruhl, G.; Fröschle, B.; Ramm, Peter; Intemann, A.; Pamler, W.

doi:10.1016/0169-4332(95)00151-4

Cited by 16 publications

(3 citation statements)

References 5 publications

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“…W chemical vapor deposition ͑CVD͒ from WF 6 -the process of choice for filling high aspect ratio holes in ultralarge-scale integrated ͑ULSI͒ circuits [1][2][3][4][5][6] -requires the use of conformal TiN/Ti bilayers. TiN is used as a diffusion barrier to prevent WF 6 reaction with underlying layers, [7][8][9][10] and Ti getters interfacial oxygen from the surface of the underlayers ͑e.g., Al͒ to reduce via resistance. On substrates such as Si and SiO 2 , Ti also serves as an adhesion promoter by reacting to form a thin TiSi 2 layer.…”

Section: Introductionmentioning

confidence: 99%

W deposition and titanium fluoride formation during WF6 reduction by Ti: Reaction path and mechanisms

Ramanath

Greene

Carlsson

et al. 1999

Journal of Applied Physics

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Reaction of WF 6 with air-exposed 27-and 250-nm-thick Ti films has been studied using Rutherford backscattering spectroscopy, scanning and high-resolution transmission electron microscopy, electron and x-ray diffraction, and x-ray photoelectron spectroscopy. We show that W nucleates and grows rapidly at localized sites on Ti during short WF 6 exposures ͑Ϸ6 s͒ at 445°C at low partial pressures p WF 6 Ͻ0.2 Torr. Large amounts of F, up to Ϸ2.0ϫ10 17 atoms/cm 2 corresponding to an average F/Ti ratio of 1.5 in a 27-nm-thick Ti layer, penetrate the Ti film, forming a solid solution and nonvolatile TiF 3. The large stresses developed due to volume expansion during fluorination of the Ti layer result in local delamination at the W/Ti and the Ti/SiO 2 interfaces at low and high WF 6 exposures, respectively. WF 6 exposure at p WF 6 Ͼ0.35 results in the formation of a network of elongated microcracks in the W film which allow WF 6 to diffuse through and attack the underlying Ti, consuming the 27-nm-thick Ti film through the evolution of gaseous TiF 4 .

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Section: Introductionmentioning

confidence: 99%

W deposition and titanium fluoride formation during WF6 reduction by Ti: Reaction path and mechanisms

Ramanath

Greene

Carlsson

et al. 1999

Journal of Applied Physics

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“…If the adhesion is strong, then base growth will be the dominant mechanism, else the mechanism will be tip growth where the catalyst nanoparticles are lifted during the growth process. TiN x is widely used as an adhesion and barrier layer for metals [11], hence its strong interactions with the metal catalyst influences the base growth mechanism observed. Also, nanotubes formed by tip growth has typically larger diameter compared to that of base growth.…”

Section: Mems Nano and Smart Systemsmentioning

confidence: 99%

Multiwalled Carbon Nanotube Growth Mechanism on Conductive and Non-Conductive Barriers

Teh¹,

Bien²,

Saman³

et al. 2011

AMR

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We report on the catalytic growth of multiwalled carbon nanotubes by plasma enhanced chemical vapor deposition using Ni and Co catalyst deposited on SiO2, Si3N 4,ITO and TiN Xbarrier layers; layers which are typically used as diffusive barriers of the catalyst material. Results revealed higher growth rates on conductive ITO and TiN Xas compared to non con-ductiveSiO2, and Si3N 4,barriers. Micrograph images reveal the growth mechanism for nanotubes grown on SiO2, Si3N 4 and ITO to be tip growth while base growth was observed for the TiN X barrier layer. Initial conclusion suggests that conductive diffusion barrier surfaces promotes growth rates however it is possible that multiwalled carbon nanotubes grown onSiO2, and Si3N 4,were encumbered as a result of the formation of silicide as shown in the results here.

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“…Metal is deposited inside a trench-type pattern mold having a narrow width and a deep depth to form interconnections with a large cross-sectional area in a limited space. Tungsten shows good gap-filling characteristics due to its high step coverage obtained through chemical vapor deposition; thus, it has been used to fill the inside of a deep mold and make vertical structures with high aspect ratios, such as via and plug structures [4]- [7]. Tungsten is commonly used as an interconnection metal for highly integrated patterns due to its advantage of being able to fill the inside of a deep trench mold with a narrow width and pitch.…”

Section: Introductionmentioning

confidence: 99%

Stress Analysis of Tungsten Deposition in a 3D Trench Mold With Regard to Initial Nuclei Shape

et al. 2022

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Tungsten has been commonly used for fine interconnects due to its good gap-filling characteristics in 3D molds, such as trench patterns. However, tungsten shows high deposition stress. This causes mold distortion because tungsten has low ad-atom mobility, and diffusion-driven relaxation does not occur. To reduce tungsten's deposition stress, the shape of the nuclei can be controlled, which is an effective way to suppress the mechanical deformation caused by the formation of a grain boundary between free surfaces during the coalescence stage. In this study, elliptical tungsten nuclei with various aspect ratios, which suppress coalescence in the early stage of deposition, were proposed to reduce the deposition stress. Stress was calculated using the finite element method (FEM) in the range of 0.5 to 8 radius ratios of the tungsten nuclei. The bending of the trench mold was calculated due to tungsten stress and additional coalescence between films during the filling process. As a result, the wider the elliptical nucleus was, the lower the film stress, and mold bending between line patterns was also reduced. The defects in the depth and width of the periodic trench influenced the mold bending in the early growth stage and the stage of coalescence between films, respectively.

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Deposition of titanium nitride/tungsten layers for application in vertically integrated circuits technology

Cited by 16 publications

References 5 publications

W deposition and titanium fluoride formation during WF6 reduction by Ti: Reaction path and mechanisms

W deposition and titanium fluoride formation during WF6 reduction by Ti: Reaction path and mechanisms

Multiwalled Carbon Nanotube Growth Mechanism on Conductive and Non-Conductive Barriers

Stress Analysis of Tungsten Deposition in a 3D Trench Mold With Regard to Initial Nuclei Shape

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