Damage Free Cryogenic Etching of a Porous Organosilica Ultralow-k Film

Zhang, Liping; Ljazouli, Rami; Lefaucheux, Philippe; Tillocher, Thomas; Dussart, Rémi; Mankelevich, Yu. A.; Marneffe, Jean‐François de; Gendt, Stefan De; Baklanov, Mikhaı̈l R.

doi:10.1149/2.007302ssl

Cited by 34 publications

(20 citation statements)

References 11 publications

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“…The EDL is calculated based on the FTIR loss of Si-CH 3 bonds, as described in our previous work. 14 The EDL is an artificial representation of damage, assuming that carbon depletion is not gradual along the film depth but with a clear interface separating a fully damaged region (100% Si-C depletion) from a intact region (0% Si-C depletion). The EDL allows more direct comparison of samples etched with different conditions and thus different final thicknesses.…”

Section: Resultsmentioning

confidence: 99%

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Zhang

Marneffe

Heyne

et al. 2014

ECS J. Solid State Sci. Technol.

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The pore stuffing method is studied with the objective of improving the plasma induced damage for porous organo-silicate glass low-k dielectrics. Experiments on blanket films show that, pore stuffing reduces the low-k degradation compared to non-protected porous films during plasma etch. The post etch surface roughness is also improved. The protection mechanism is attributed to reduced radical penetration, mainly fluorine and oxygen. The resistance against vacuum UV degradation is also improved by pore stuffing, since polymers used as filling agents have a higher VUV absorption coefficient than Si-O based dielectric network. The protection effect against fluorocarbon-based gas discharges is extensively studied with both blanket and patterned samples. For patterning of porous, non-stuffed low-k films, the addition of polymerizing gas reduces surface plasma damage but this polymerizing protection effect doesn't work well on trench sidewalls. Pore stuffing enables an efficient sidewall protection even with oxidizing gas discharges.

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Section: Resultsmentioning

confidence: 99%

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Zhang

Marneffe

Heyne

et al. 2014

ECS J. Solid State Sci. Technol.

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“…30 In our recent work, we demonstrated that the damage reduction during the etching in Fluorine based plasma occurs thanks to "sealing" of the open pores by reaction byproducts. 31 It has been proven that these reaction products are stable up to room temperature, and can be removed by annealing, leaving an undamaged low-k material.…”

mentioning

confidence: 99%

“…EDL is the "equivalent damaged layer" measured from the Si-CH 3 depletion (FTIR), assuming a sharp interface between the pristine and damaged layers 31. …”

mentioning

confidence: 99%

Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF₆/O₂/SiF₄

Zhang

Ljazouli

Lefaucheux

et al. 2013

ECS J. Solid State Sci. Technol.

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Low temperature plasma etching of porous organosilicate low-k films is studied, in an ICP chamber with cryo-cooled substrate holder, using Fluorine-based plasma discharges. It is demonstrated that plasma-induced damage is significantly reduced when the base temperature is below a threshold T c that depends on pore size of low-k materials. For T < T c , almost no carbon depletion is observed and the k-value degradation is negligible. It is shown that protection occurs mainly through the condensation of the etch by-products and their ability to seal the open pores against radical diffusion. By addition of SiF 4 and O 2 into the gas discharge, plasma-induced damage is further reduced, as a result of SiO x F y deposition. Vertical trench profiles are obtained in patterned structures, using an inorganic hard mask. The damage reduction mechanism is discussed and a protection model is proposed.

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“…This blocks the radicals diffusion and prevents plasma-induced damage. [23,24] Cryogenic plasmas have been investigated for years for deep silicon etching. [25] The concept consists in the deposition of SiOF passivation layers at Si patterns sidewalls at low temperature to block the lateral etching.…”

Section: Cryogenic Plasma Etchingmentioning

confidence: 99%

Prospects for dielectric constant reduction in integrated circuits interconnects

et al. 2014

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To improve the integrated circuits' performance and continue the downscaling of dimensions, it is necessary to use low dielectric constant materials as interconnects insulators. Current porous SiCOH low-k dielectrics are now reaching their limits since their porosity enables the diffusion of species that modify the inner surface of the pores. To further reduce the dielectric constant, it is necessary to change paradigm in interconnects fabrication. In this paper, we discuss the most promising innovations in terms of process, materials and architectures to reduce the interconnects insulators dielectric constant.

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Damage Free Cryogenic Etching of a Porous Organosilica Ultralow-k Film

Cited by 34 publications

References 11 publications

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF₆/O₂/SiF₄

Prospects for dielectric constant reduction in integrated circuits interconnects

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Damage Free Cryogenic Etching of a Porous Organosilica Ultralow-k Film

Cited by 34 publications

References 11 publications

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Improved Plasma Resistance for Porous Low-k Dielectrics by Pore Stuffing Approach

Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF6/O2/SiF4

Prospects for dielectric constant reduction in integrated circuits interconnects

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Low Damage Cryogenic Etching of Porous Organosilicate Low-k Materials Using SF₆/O₂/SiF₄