Effect of the dielectric–substrate interface on charge accumulation from vacuum ultraviolet irradiation of low-k porous organosilicate dielectrics

Sinha, H.; Sehgal, Akshey; He, Rong; Nichols, M. T.; Tomoyasu, M.; Russell, N. M.; Nishi, Yoshio; Shohet, J. L.

doi:10.1016/j.tsf.2011.03.010

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…The purpose of this section is to indicate what differences in VUV response are observed for industrially relevant SiCN/SiCOH/SiCN/Cu stacks exposed to plasma etch, as compared to samples on Si with or without native oxide. 364,367,368 Here, dielectric films deposited on Cu and, for comparison, model Si/SiO2 films, were irradiated with VUV photons having energies and fluxes typically generated during plasma processing. It was found that the nature of the dielectric-substrate interface changes the number of trapped charges in the dielectric.…”

Section: Iv5 Effect Of Dielectric-substrate Interface On Charge Trappingmentioning

confidence: 99%

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Baklanov

Jousseaume

Рахимова

et al. 2019

Applied Physics Reviews

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This paper presents an in-depth overview of the application and impact of UV/VUV light in advanced interconnect technology. UV light application in BEOL historically was mainly motivated by the need to remove organic porogen and generate porosity in organosilicate (OSG) low-k films. Porosity lowered the film's dielectric constant, k, which enables one to reduce the interconnect wiring capacitance contribution to the RC signal delay in integrated circuits. The UV-based low-k film curing (λ > 200 nm) proved superior to thermal annealing and electron beam curing. UV and VUV light also play a significant role in plasma-induced damage to pSiCOH. VUV light with λ < 190–200 nm is able to break Si-CH3 bonds and to make low-k materials hydrophilic. The following moisture adsorption degrades the low-k properties and reliability. This fact motivated research into the mechanisms of UV/VUV photon interactions in pSiCOH films and in other materials used in BEOL nanofabrication. Today, the mechanisms of UV/VUV photon interactions with pSiCOH and other films used in interconnect fabrication are fairly well understood after nearly two decades of research. This understanding has allowed engineers to both control the damaging effects of photons and utilize the UV light for material engineering and nanofabrication processes. Some UV-based technological solutions, such as low-k curing and UV-induced stress engineering, have already been widely adopted for high volume manufacturing. Nevertheless, the challenges in nanoscaling technology may promote more widespread adoption of photon-assisted processing. We hope that fundamental insights and prospected applications described in this article will help the reader to find the optimal way in this wide and rapidly developing technology area.

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Section: Iv5 Effect Of Dielectric-substrate Interface On Charge Trappingmentioning

confidence: 99%

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Baklanov

Jousseaume

Рахимова

et al. 2019

Applied Physics Reviews

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“…The purpose here is to determine what differences in VUV response are observed for industrially relevant SiCN/SiCOH/SiCN/Cu stacks exposed to plasma etch, as compared to samples on Si with or without native oxide, similar to those described in other sections. [83][84][85] Here, dielectric films deposited on Cu and, for comparison, model Si/SiO2 films were irradiated with VUV photons having energies and fluxes typically generated during plasma processing. It was found that the nature of the dielectric-substrate interface changes the number of trapped charges in the dielectric.…”

Section: Effect Of Dielectric-substrate Interface On Charge Trappingmentioning

confidence: 99%

The effects of vacuum ultraviolet radiation on low-k dielectric films

Sinha

Nichols

et al. 2012

Journal of Applied Physics

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Plasmas, known to emit high levels of vacuum ultraviolet (VUV) radiation, are used in the semiconductor industry for processing of low-k organosilicate glass (SiCOH) dielectric device structures. VUV irradiation induces photoconduction, photoemission, and photoinjection. These effects generate trapped charges within the dielectric film, which can degrade electrical properties of the dielectric. The amount of charge accumulation in low-k dielectrics depends on factors that affect photoconduction, photoemission, and photoinjection. Changes in the photo and intrinsic conductivities of SiCOH are also ascribed to the changes in the numbers of charged traps generated during VUV irradiation. The dielectric-substrate interface controls charge trapping by affecting photoinjection of charged carriers into the dielectric from the substrate. The number of trapped charges increases with increasing porosity of SiCOH because of charge trapping sites in the nanopores. Modifications to these three parameters, i.e., (1) VUV induced charge generation, (2) dielectric-substrate interface, and (3) porosity of dielectrics, can be used to reduce trappedcharge accumulation during processing of low-j SiCOH dielectrics. Photons from the plasma are responsible for trapped-charge accumulation within the dielectric, while ions stick primarily to the surface of the dielectrics. In addition, as the dielectric constant was decreased by adding porosity, the defect concentrations increased. V

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“…Given that the photon flux density is the same for both exposures, this implies that the photoemission yield (photoemitted electrons per incident photon) is larger for the structures with the 10 nm thick HfO 2 surface layer. 28 Figure 6 shows two surface-potential maps measured across an oxidized wafer (without the HfO 2 coating). Typically, for unpatterned wafers during VUV irradiation, the rate of decrease of the current drawn by the substrate is inversely proportional to the increase in the surface potential.…”

Section: A Plasma-induced Charging Of Patterned Structuresmentioning

confidence: 99%

Plasma and vacuum ultraviolet induced charging of SiO2 and HfO2 patterned structures

Lauer

Upadhyaya

Sinha

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Characterization of atomic layer deposition HfO2, Al2O3, and plasma-enhanced chemical vapor deposition Si3N4 as metal-insulator-metal capacitor dielectric for GaAs HBT technology J. Vac. Sci. Technol. A 31, 01A134 (2013); 10.1116/1.4769207 In situ study of the atomic layer deposition of HfO2 on Si J. Vac. Sci. Technol. A 30, 01A143 (2012); 10.1116/1.3668080Effect of thermal annealing on charge exchange between oxygen interstitial defects within HfO 2 and oxygendeficient silicon centers within the SiO 2 / Si interface Appl.The authors compare the effects of plasma charging and vacuum ultraviolet (VUV) irradiation on oxidized patterned Si structures with and without atomic-layer-deposited HfO 2 . It was found that, unlike planar oxidized Si wafers, oxidized patterned Si wafers charge up significantly after exposure in an electron-cyclotron resonance plasma. The charging is dependent on the aspect ratio of the patterned structures. This is attributed to electron and/or ion shading during plasma exposure. The addition of a 10 nm thick HfO 2 layer deposited on top of the oxidized silicon structures increases the photoemission yield during VUV irradiation, resulting in more trapped positive charge compared to patterns without the HfO 2 dielectric.

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Effect of the dielectric–substrate interface on charge accumulation from vacuum ultraviolet irradiation of low-k porous organosilicate dielectrics

Cited by 6 publications

References 21 publications

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

Impact of VUV photons on SiO2 and organosilicate low-k dielectrics: General behavior, practical applications, and atomic models

The effects of vacuum ultraviolet radiation on low-k dielectric films

Plasma and vacuum ultraviolet induced charging of SiO2 and HfO2 patterned structures

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