Minimization of plasma ashing damage to OSG low-k dielectrics

Shi, Hua‐Tian; Huang, Huai; Im, James S.; Ho, Paul S.; Zhou, Yifeng; Pender, J.; Armacost, M.; Kyser, David F.

doi:10.1109/iitc.2010.5510308

Cited by 7 publications

(10 citation statements)

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“…In particular, it has been determined that the dielectric constant of SiO 2 can be reduced by using doping with carbon-containing organics. ,, The resulting SiCOH materials have dielectric constants in the range from 2.7 to 3.0, and even lower values are possible by adding porosity. On the flip side, these new materials exhibit limited chemical stability, requiring special care during microelectronics manufacturing. ,− One of most difficult challenges when patterning the SiCOH dielectric is to minimize damage during the photoresist stripping processes, which typically relies on the use of plasmas with ions and radicals that can remove methyl groups from the surface of the SiCOH. , Because of this, the surface becomes hydrophilic, facilitating water absorption and leading to an increase in the dielectric constant of the material. ,, Several processes have been developed to minimize these problems, but those are multistep and introduce additional complications. ,− …”

Section: Introductionmentioning

confidence: 99%

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

Guo

Qin

Zaera

2016

ACS Appl. Mater. Interfaces

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A protocol has been developed to selectively process low-k SiCOH dielectric substrates in order to activate or deactivate them toward the deposition of thin solid films by chemical (CVD or ALD) means. The original SiCOH surfaces are hydrophobic, an indication that they are alkyl- rather than silanol-terminated and that, consequently, they are fairly unreactive. However, the chemical-mechanical polishing (CMP) sometimes done during microelectronics fabrication renders them hydrophilic and reactive. It was shown here that silylation of the CMP-treated surfaces with any of a number of well-known silylation agents such as HMDS, ODTS, or OTS caps the reactive silanol surface groups and turns them back to being hydrophilic and unreactive. Further exposure of any of the passivated surfaces to a combination of ozone and UV radiation reinstates their hydrophilicity and chemical activity. Importantly, it was also demonstrated that all these changes could be induced without altering the original mechanical, optical, or electrical properties of the samples: atomic force microscopy (AFM) images show no increase in roughness, ellipsometry measurements yield the same values for the index of refraction and dielectric constant, and infrared absorption spectroscopy attests to the preservation of the organic fragments present in the original SiCOH samples. The chemical selectivity of the resulting surfaces was tested for the atomic layer deposition (ALD) of HfO2 films, which could be grown only on the UV/O3 treated substrates.

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Section: Introductionmentioning

confidence: 99%

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

Guo

Qin

Zaera

2016

ACS Appl. Mater. Interfaces

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“…It was reported that higher carbon concentration in porous OSG low-k dielectrics contributes to higher resistance to Oxygen plasma. 12,13 Different optimized patterning schemes have also been proposed. These are the so-called "Post Integration Porogen Removal " [14][15][16] and "Post Porosity Plasma Protection -P4" approaches.…”

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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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“…Hence, the process integration and resist strip conditions must be chosen carefully to minimize etch damage [55][56][57][58][59]. Hence, the process integration and resist strip conditions must be chosen carefully to minimize etch damage [55][56][57][58][59].…”

Section: Dielectric Patterningmentioning

confidence: 99%

“…Acceptable resist etch rates (100 nm/min) can be achieved by using a high temperature (260°C) downstream H 2 plasma. The CO-or CO 2 -based resist strip approaches are generally run in RIE tools [55,65,66]. The downstream H 2 plasma only reacts with H in the low-k film, in a replacement reaction, without altering the stoichiometry of the film [64].…”

Section: Dielectric Patterningmentioning

confidence: 99%

“…The CO-or CO 2 -based resist strip approaches are generally run in RIE tools [55,65,66]. Another possible reason for low damage with CO-and CO-based strips is the formation of a C-rich passivation layer on pores and sidewalls of the low-k material [55]. During patterning, the top surface of the low-k dielectric is typically capped with a hard dielectric such as SiO 2 (i.e., in the multilayer resist approach; Figure 8.13).…”

Section: Dielectric Patterningmentioning

confidence: 99%

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Process Technology for Copper Interconnects

Gambino

2012

Handbook of Thin Film Deposition

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Minimization of plasma ashing damage to OSG low-k dielectrics

Cited by 7 publications

References 2 publications

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

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

Process Technology for Copper Interconnects

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Minimization of plasma ashing damage to OSG low-k dielectrics

Cited by 7 publications

References 2 publications

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

Chemical Treatment of Low-k Dielectric Surfaces for Patterning of Thin Solid Films in Microelectronic Applications

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

Process Technology for Copper Interconnects

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Product

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