Properties of TaN<i>x</i> films as diffusion barriers in the thermally stable Cu/Si contact systems

Takeyama, Mayumi B.; Noya, Atsushi; Sase, Touko; Ohta, Akira; Sasaki, Katsutaka

doi:10.1116/1.589155

Cited by 108 publications

(46 citation statements)

References 6 publications

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“…Ta 2.67 N was measured via a four-point probe, and the thickness measured via an alpha-step 200 profilometer. The extracted resistivity was ∼267 -cm, so the composition of TaN X should be close to Ta 2 N. 40 The Ta 4f 7/2 peak is shifted 0.77 eV relative to the Ta 4f 7/2 metallic line (21.9 eV) (Fig. 8), also indicating that the TaN X was close to Ta 2 N (0.6 eV shift).…”

Section: Tan X Overlayersmentioning

confidence: 94%

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Stability of fluorinated parylenes to oxygen reactive-ion etching under aluminum, aluminum oxide, and tantalum nitride overlayers

Senkevich

Wang

Fortin

et al. 2003

Journal of Elec Materi

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A driving force in the semiconductor industry has been the reduction in feature size to increase the speed and functionality per unit area. As the minimum feature size has been reduced to the submicron regime, the benefit of further reduction of device size will be increasingly offset by the interconnect or resistance capacitance (RC) delay. 1 With the intensified search for ultra-low dielectric-constant materials ( < 2.2), fluorination of polymeric materials is an option to reduce the dielectric constant of hydrocarbon polymers while still retaining a dense dielectric. To be compatible with copper-damascene processing, the low-interlayer dielectric (ILD) must possess a robust interface with copper-diffusion barriers, adhesion layers, or dielectric liners, depending on the back end of the line-metallization scheme. The presence of fluorine in the ILD, however, presents reliability concerns as any fluorine instability might seriously undermine diffusion/adhesion liners and copper wires. The present work investigates the stability of two fluorinated-parylene polymers before and after oxygen reactive-ion etching (RIE) in contact with Al, Al 2 O 3 , and TaN X overlayers. It is important to understand the chemical interaction between the fluorinated ILD and the barrier overlayer because trench formation in Cu-damascene architecture could be undertaken via oxygen RIE of the ILD.With the primary goal to improve adhesion, numerous research papers have devoted attention to the interface between metal films and surfacemodified fluoropolymers. Surface modification has been achieved by low-energy ion beams; 2,3 argon plasma; 4 water-vapor plasma; 5 remote-hydrogen plasma; 6,7 oxygen plasma; 8 filament-assisted watervapor modification; 9,10 strong bases, such as KOH and LiOH; 11,12 solution-borne reducing agents, such as benzoin dianion/DMSO and NaBH 4 ; 13,14 and solvated electrons. 15,16 Further, a book and a review article discuss the surface modification of polymeric surfaces via plasmas. 17,18 However, it is the particular interest here to study how fluorocarbons interact with oxidizing plasmas.There are two components of a typical plasma that can damage or etch a polymeric surface, the The fluorine stability of two parylenes, aliphatic-fluorinated AF-4 (␣, ␣, ␣Ј, ␣Ј poly(p-tetrafluoroxylylene) and aromatic-fluorinated VT-4 (2, 3, 5, 6 poly(p-tetrafluoroxylylene), were investigated underneath Al, Al 2 O 3 , and TaN X overlayers with and without exposure to oxygen reactive-ion etching (RIE). No fluorine diffusion was observed for Al films deposited onto the as-received parylenes. However, after oxygen RIE, x-ray photoelectron spectroscopy (XPS) depth profiling detected fluorine diffusion throughout Al and to a lesser extent Al 2 O 3 but in contrast to Ta 2.67 N. Metal-fluoride bonding was evident at the metal/parylene interface for all the overlayers after the parylene was exposed to oxygen RIE and annealed.

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Section: Tan X Overlayersmentioning

confidence: 94%

“…39,40 Grain-boundary diffusion is thought to be the dominant diffusion mechanism at low temperatures. 41,42 However, with the proper adjustment of the nitrogen flow with reactive sputtering, TaN X can also be made amorphous.…”

Section: Tan X Overlayersmentioning

confidence: 99%

Stability of fluorinated parylenes to oxygen reactive-ion etching under aluminum, aluminum oxide, and tantalum nitride overlayers

Senkevich

Wang

Fortin

et al. 2003

Journal of Elec Materi

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“…Its presence in silicon leads to the formation of deep trap levels, which affects the effective doping concentration, reduces the lifetime of the minority carriers, and increases the junction leakage current. 2 In addition, Cu drifts through SiO 2 easily under field acceleration. 3 Therefore, a critical issue in constructing a reliable Cu-based metallization structure is to develop an appropriate diffusion barrier that prevents undesirable interactions between Cu and the dielectric, as well as the underlying substrate.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of potential NiMoP diffusion barrier/seed layers for Cu interconnects via electroless deposition

Wan

Wang

2005

Journal of Elec Materi

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Potential NiMoP barrier/seed layers for Cu interconnects have been successfully formed by electroless deposition on SiO 2 . Four different wet processes were attempted to activate the surface before electroless deposition. Material properties including the crystal structure, deposition rate, composition, and electrical resistivity of NiMoP layers were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), Auger electron spectroscopy, x-ray diffraction (XRD), four-point probe, and surface profilometry (Alpha-step). In this study, different compositions of NiMoP films have been obtained. Ni 89 Mo 2 P 9 with nanocrystalline structure has the highest resistivity due to enriched P content, while Ni 88 Mo 9 P 3 has the lowest value among the compositions considered in this study. The seed layer and the barrier layer functions of NiMoP were verified by direct Cu electrodeposition and secondary ion mass spectroscopy (SIMS).

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“…• C for 1h, however, barrier property of Cu/TaN/Si layered structures was broken and formation of TaSi 2 and Cu 3 Si were observed [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…• C), low electrical resistivity and high thermal conductivity [1][2][3][4][5][6][7], which make it possible to use as a diffusion barrier between Copper (Cu) wiring and interlayer dielectric film in ultra large scale integrated circuits (ULSIs) [2][3][4][5][6][7][8][9][10]. TaN can also be used in wide variety of applications such as corrosion-resistant materials, write-head materials in high-density magnetic recording and high-speed thermal printing head as well as thin film resistors.…”

Section: Introductionmentioning

confidence: 99%

Deposition of TaN Films by RF Sputtering and Their Barrier Properties in Cu/TaN/Dielectrics/Si MIS Structures

Tajima

Katsumata

Uekusa

2012

e-J. Surf. Sci. Nanotechnol.

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The electrical resistivity and the barrier property of Tantalum nitride (TaN) thin films were systematically investigated as a function of annealing temperature using two different types of MIS structures of TaN/SiO2/Si and Cu/TaN/dielectric/Si(100), where either the thermally grown SiO2 (th-SiO2) or spin-on dielectric (SOD) hydrogen silsesquioxane (HSQ) films was used as a dielectric layer. We observed that the resistivity of TaN thin films before Cu deposition became lower with the growth of TaN (200) as compared with the growth of TaN (111) and TaN(220). Cu diffusion barrier properties of MIS diodes with TaN films were improved up to 500• C for both dielectric films due presumably to the decrease in sputter damage of dielectric films by annealing, while those without TaN thin films were degraded due to the diffusion of Cu into the dielectric films. The oxygen desorption from dielectric films and the oxidation of TaN films due to the reverse-sputtering of dielectric films during the sputtering of Ta in N2 is possible model of sputter damage.

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Properties of TaNx films as diffusion barriers in the thermally stable Cu/Si contact systems

Cited by 108 publications

References 6 publications

Stability of fluorinated parylenes to oxygen reactive-ion etching under aluminum, aluminum oxide, and tantalum nitride overlayers

Stability of fluorinated parylenes to oxygen reactive-ion etching under aluminum, aluminum oxide, and tantalum nitride overlayers

Fabrication of potential NiMoP diffusion barrier/seed layers for Cu interconnects via electroless deposition

Deposition of TaN Films by RF Sputtering and Their Barrier Properties in Cu/TaN/Dielectrics/Si MIS Structures

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