Etch mechanisms of low dielectric constant polymers in high density plasmas: Impact of charging effects on profile distortion during the etching process

Fuard, D.; Joubert, O.; Vallier, L.; Assous, M.; Berruyer, P.; Blanc, R.

doi:10.1116/1.1420492

Cited by 34 publications

(27 citation statements)

References 14 publications

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“…[1][2][3] Before low-k materials can be implemented successfully, many problems must be solved. An important problem that we are facing today is that electric signal propagation through metal interconnects is delayed by the resistance in the metal lines and the capacitance between adjacent metal lines.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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“…Plasma etching processes used for organic low-k are based on oxygen or hydrogen radicals. [43] Passivating agents such as sulfur-containing species may be required to passivate patterns sidewalls and prevent lateral etching. [44] Organic low-k are resistant to copper diffusion, which enables the integration without metallic barrier, increasing the copper cross section and reducing the line resistance.…”

Section: Organic Low-kmentioning

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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“…Anisotropy of the etched feature is important as bowed profiles 36 in the resist could affect the etch profiles of the subsequent layers. Also, the CD bias, defined here as the difference between the bottom CD ͓CD at the underlayer-oxide interface, Fig.…”

Section: Cross Section Profilesmentioning

confidence: 99%

Etching silicon-containing bilayer resists in ammonia-based plasmas

Panda¹,

Wise²,

Mahorowala³

et al. 2005

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

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The need to print smaller feature sizes has led to the shift from 248nmto193nm lithography. The disadvantages of 193nm ArF single-layer resist materials, such as lower depth of focus and lower etch resistance, have made thin-film imaging (TFI) techniques an attractive alternative. In the bilayer (comprised of an image layer and an underlayer) approach, a form of TFI, O2-based plasma chemistries are used for the transfer etches whereby oxidation of silicon in the image layer provides the required etch resistance. However, use of oxygen results in profile and critical dimension (CD) control issues. While gas additives have helped minimize these problems, there are other accompanying disadvantages. In this work, the feasibility of a non-O2-containing NH3-based plasma etch chemistry was evaluated. Effects of additive gases, such as N2, H2, and C2H4, were investigated. Surface analysis of the resist showed that nitrogen from the gas phase was incorporated in the surface of the image layer during the etch, and the etch resistance increased with this nitrogen content. Gas phase analysis showed that the relative N2H species density in the system was correlated with the nitrogen incorporated in the image layer, and is thus believed to govern the etch resistance of the image layer. The underlayer etch behavior was correlated with that of the atomic hydrogen species density. The effect of the additives on the cross section profiles and line edge roughness were studied. The highest CD biases were obtained with H2 as the additive, while near-zero CD biases were attained with C2H4 as the additive. Also, with the C2H4 additive, minimum line edge roughness and smoothest profiles were obtained.

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Etch mechanisms of low dielectric constant polymers in high density plasmas: Impact of charging effects on profile distortion during the etching process

Cited by 34 publications

References 14 publications

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

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

Prospects for dielectric constant reduction in integrated circuits interconnects

Etching silicon-containing bilayer resists in ammonia-based plasmas

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