Study of nanocrystalline Ta(N,O) diffusion barriers for use in Cu metallization

Stavrev, M.; Fischer, D.; Preuß, Andrea; Wenzel, Christian; Mattern, N.

doi:10.1016/s0167-9317(96)00054-8

Cited by 28 publications

(10 citation statements)

References 8 publications

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“…8 Hence, it is not surprising that tantalum and its compounds have been suggested as a feasible diffusion barrier in copper-based metallization schemes by a number of authors. [8][9][10][11][12][13][14][15] The results and their interpretations are, however, quite contradictory. No general agreement concerning the reactions in the Si/Ta/Cu system has been achieved.…”

Section: Introductionmentioning

confidence: 99%

Failure mechanism of Ta diffusion barrier between Cu and Si

Laurila¹,

Zeng²,

Kivilahti³

et al. 2000

Journal of Applied Physics

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The reaction mechanisms in the Si/Ta/Cu metallization system and their relation to the microstructure of thin films are discussed on the basis of experimental results and the assessment of the ternary Si-Ta-Cu phase diagram at 700°C. With the help of sheet resistance measurements, Rutherford backscattering spectroscopy, x-ray diffraction, a scanning electron microscope, and a transmission electron microscope, the Ta barrier layer was observed to fail at temperatures above 650°C due to the formation of TaSi 2 , the diffusion of Cu through the silicide layer, and the resulting formation of Cu 3 Si precipitates. However, in order for the TaSi 2 phase to form first, the Ta diffusion barrier layer must be thick enough ͑e.g., 50-100 nm͒ to prevent Cu diffusion into the Si substrate up to the temperature of TaSi 2 formation ͑ϳ650°C͒. Independent of the Ta layer thickness, Cu 3 Si was present as large nodules, whereas the TaSi 2 existed as a uniform layer. The resulting reaction structure was found to be in local equilibrium on the basis of the assessed Si-Ta-Cu phase diagram at 700°C, and therefore no further reactions were expected. The role of oxygen was also found to be important in the reactions and it seems to have a strong effect on the thermal stability of the barrier layer.

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Section: Introductionmentioning

confidence: 99%

Failure mechanism of Ta diffusion barrier between Cu and Si

Laurila¹,

Zeng²,

Kivilahti³

et al. 2000

Journal of Applied Physics

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“…S. Beck obtained a steep profile of the TiN/TaN stack using oxide mask and BCl 3 and/or Cl 2 /HBr. However, during the high-k etch process with BCl 3 chemistry, TaN thin film was removed laterally and formed a undercut profile [6][7][8]. In our experiment, O 2 /CF 4 /Ar plasma was selected as the etching gas chemistry because O 2 /CF 4 /Ar plasma was widely used due to its high selectivity and possible formation of a passivation layer.…”

Section: Introductionmentioning

confidence: 99%

Chemical Reaction on Etched TaNO Thin Film as O₂ Content Varies in CF₄/Ar Gas Mixing Plasma

Woo¹,

KimChangIl²

2017

Transactions on Electrical and Electronic Materials

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The TaNO thin films were fabricated on standard 8 inch silicon wafers with a resistivity of 15 ~ 25 Ohm·cm. The TaNO thin film produced by the oxidation of deposited TaN films at 400℃ had a Vol. 18, No. 2, pp. 74-77, April 25, 2017 pISSN: 1229-7607 eISSN: 2092 Jong Chang Woo TRANSACTIONS ON ELECTRICAL AND ELECTRONIC MATERIALS Department of Electronic Automation Engineering, Daeduk University, Daejeon 34111, KoreaChang-Il Kim School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, KoreaReceived September 20, 2016; Accepted November 22, 2016In this work, we investigated the etching characteristics of TaNO thin films and the selectivity of TaNO to SiO 2 in an O 2 /CF4/Ar inductively coupled plasma (ICP) system. The maximum etch rate of TaNO thin film was 297.1 nm/min at a gas mixing ratio of O 2 /CF 4 /Ar (6:16:4 sccm). At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage, and process pressure. X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment, as well as the accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the CF 4 -containing plasmas.

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“…[1][2][3][4][5][6][7][8][9][10] The Ta layer contributes to the adhesion ability between TaN x and Cu metals while the TaN x film is used as an adhesion layer between Ta and dielectric films. Previous studies have pointed out that a TaN x film with an amorphous structure had better barrier property than a Ta metal to keep Cu from diffusion into dielectric films.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have pointed out that a TaN x film with an amorphous structure had better barrier property than a Ta metal to keep Cu from diffusion into dielectric films. [1][2][3][4] However, the high-resistivity TaN x film will dominate and increase overall contact resistance (Rc), as its thickness on the feature bottom is too thick. Ionized metal plasma (IMP) is the promising method for the deposition of thin barrier and seed layers in high-aspect-ratio damascene structures.…”

Section: Introductionmentioning

confidence: 99%