X-ray photoelectron spectroscopy analyses of silicon dioxide contact holes etched in a magnetically enhanced reactive ion etching reactor

Czupryński, Piotr

doi:10.1116/1.590008

Cited by 21 publications

(10 citation statements)

References 18 publications

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“…[6][7][8] . After partial etching, surface and structural modifications of the remaining films are investigated by XPS and infrared spectroscopy (FTIR).…”

Section: Methodsmentioning

confidence: 99%

Etching of porous SiOCH materials in fluorocarbon-based plasmas

Possémé

Chevolleau

Joubert

et al. 2004

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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This work focuses on the etching of different porous methylsilsesquioxane materials (spin on SiOCH, k=2.2) with different porosity (30%, 40% and 50%) in fluorocarbon-based plasmas (CF4∕Ar). The etching of these materials is performed on blanket wafers in a magnetically enhanced reactive ion etcher. The surface and bulk modification after partial etching are studied using different surface analysis techniques such as quasi-in-situ x-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), and attenuated total reflection spectroscopy (FTIR-ATR). Similar to nonporous SiOCH materials, a decrease in etch rate of porous SiOCH films is observed with either increasing Ar dilution or polymerizing gas addition (CH2F2), which can lead in this last case to an etch stop phenomenon. The etch rate increases with higher porosity in the SiOCH film, since less material per unit thickness needs to be removed as the porosity increases. The XPS results show that a fluorocarbon layer is formed at the surface of the porous material and complementary angle resolved XPS analyses reveal that fluorocarbon species diffuse through the pores into the material. After partial etching, FTIR and ATR analyses reveal a carbon depletion in the remaining film, which indicates that the porous material is altered during plasma exposure. The film degradation is more important as the porosity increases. The etch rate evolution and film degradation are discussed and interpreted in terms of etching mechanisms and plasma surface interaction.

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“…[6][7][8] . After partial etching, surface and structural modifications of the remaining films are investigated by XPS and infrared spectroscopy (FTIR).…”

Section: Methodsmentioning

confidence: 99%

Etching of porous SiOCH materials in fluorocarbon-based plasmas

Possémé

Chevolleau

Joubert

et al. 2004

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…6,7 Chemical compositions are derived from the areas of the different XPS spectra. The XPS analyses are carried out under quasi in situ conditions via a vacuum transfer of the wafer into the XPS chamber after the etch process.…”

Section: Methodsmentioning

confidence: 99%

“…In the steady state etching regime, a fluorinated layer is present at the surface of SiOCH and SiCH bulk material, below the fluorocarbon layer acting as the fluorine feedstock for the etching reactions. 6,13 The perturbed layer thickness (d lay ), formed in the steady state etching regime on top of the different materials investigated, can be calculated by monitoring the changes in Si 2p peak intensity (I Si ) occurring before and after plasma exposure. 13,14 Now assuming that the surface transformation induced by the plasma is well described by the simple model schematically shown in Fig.…”

Section: Xps Analysesmentioning

confidence: 99%

Etching mechanisms of low-k SiOCH and selectivity to SiCH and SiO2 in fluorocarbon based plasmas

Possémé¹,

Chevolleau²,

Joubert³

et al. 2003

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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A model for Si, SiCH, Si O 2 , SiOCH, and porous SiOCH etch rate calculation in inductively coupled fluorocarbon plasma with a pulsed bias: Importance of the fluorocarbon layer This study is dedicated to an analysis of the etch mechanisms of SiOCH, SiO 2 and SiCH in fluorocarbon plasmas. The etching of these materials is performed on blanket wafers in a magnetically enhanced reactive ion etcher reactor using fluorocarbon based chemistry (CF 4 /N 2 /Ar). After partial etching, the Fourier transform infrared spectroscopy and mercury probe measurement indicate that the remaining substrate of SiOCH is not altered by the reactive plasma. A decrease in the etch rate of SiOCH, SiO 2 and SiCH is observed either with increasing Ar dilution or polymerizing gas addition as CH 2 F 2 and C 4 F 6 . X-ray photoelectron spectroscopy analysis of the surface after partial etching shows that the thickness of the fluorocarbon layer formed at the film surface and its composition play a key role in controlling etch rate and selectivity of SiOCH, SiO 2 and SiCH. The etch rate of these materials is getting lower when the fluorocarbon layer thickness increases and also when its fluorine concentration decreases. The fluorocarbon layer thickness and composition depend on the plasma chemistry but also on the concentration and nature of impurities ͑C and H͒ in the etched materials. Etch rates are presented and discussed with respect to plasma parameters and material composition in terms of etching mechanisms.

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“…More details of the experimental characterization conditions can be found elsewhere. 15,16 Density and thickness evolution XRR. XRR analyses have been performed ex situ on 200 mm wafers.…”

Section: A Experimental Setupmentioning

confidence: 99%

Modifications of dielectric films induced by plasma ashing processes: Hybrid versus porous SiOCH materials

Darnon

Chevolleau

David

et al. 2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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This work focuses on the impact of oxidizing (O2) and reducing plasma ashing chemistries (NH3, CH4) on the modifications of dielectric materials in a porous or an hybrid state (SiOCH matrix+porogen). The plasma ashing processes have been performed on blanket wafers using O2, NH3, and CH4 based plasmas. The modifications of the remaining film after plasma exposures have been investigated using different analysis techniques such as x-ray photoelectron spectroscopy, infrared spectroscopy, x-ray reflectometry, and porosimetric ellipsometry. For the porous material the authors have shown that NH3 and O2 plasmas induce carbon depletion and moisture uptake while the CH4 plasma only leads to important carbon depletion without moisture uptake and to the formation of a thin carbon layer on the surface. For the hybrid material, no significant material modification is evidenced with the O2 plasma while an important methyl depletion and porogen degradation are observed with reducing chemistries such as CH4 and NH3 plasmas. The impact of the porogen on the film modification and the value of the dielectric constant will be presented and discussed.

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X-ray photoelectron spectroscopy analyses of silicon dioxide contact holes etched in a magnetically enhanced reactive ion etching reactor

Cited by 21 publications

References 18 publications

Etching of porous SiOCH materials in fluorocarbon-based plasmas

Etching of porous SiOCH materials in fluorocarbon-based plasmas

Etching mechanisms of low-k SiOCH and selectivity to SiCH and SiO2 in fluorocarbon based plasmas

Modifications of dielectric films induced by plasma ashing processes: Hybrid versus porous SiOCH materials

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