Oxide Etching Using Surface Wave Coupled Plasma

Akimoto, Takeshi; Ikawa, Eiji; Sango, Toshiaki; Komachi, K.; Katayama, Katuo; Ebata, Tosiki

doi:10.1143/jjap.33.7037

Cited by 19 publications

(13 citation statements)

References 9 publications

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“…In particular, it has been recently revealed that inductively coupled ͑IC͒ and surface wave sustained ͑SWS͒ plasmas produced in C 4 F 8 ϩAr gas mixtures have an outstanding potential for ultra-fine and highly selective etching of large-area polysilicon wafers. 2,3 Physically, it appears possible to achieve high dissociation rates of the feedstock gas and densities (ϳ10 13 cm Ϫ3 ) of neutral radicals at low ͑ϳ20 mTorr͒ pressures.…”

Section: Introductionmentioning

confidence: 99%

Charging and trapping of macroparticles in near-electrode regions of fluorocarbon plasmas with negative ions

2001

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Charging and trapping of macroparticles in the near-electrode region of fluorocarbon etching plasmas with negative ions is considered. The equilibrium charge and forces on particles are computed as a function of the local position in the plasma presheath and sheath. The ionic composition of the plasma corresponds to the etching experiments in 2.45 GHz surface-wave sustained and 13.56 MHz inductively coupled C4F8+Ar plasmas. It is shown that despite negligible negative ion currents collected by the particles, the negative fluorine ions affect the charging and trapping of particulates through modification of the sheath/presheath structure.

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Section: Introductionmentioning

confidence: 99%

Charging and trapping of macroparticles in near-electrode regions of fluorocarbon plasmas with negative ions

2001

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“…9,10 In this article, we consider the charging of micron-size particulates in fluorocarbon plasmas frequently used for ultrafine, highly efficient, and selective etching of dielectric materials. 11,12 We demonstrate that in plasmas of fluorocarbon-argon gas mixtures, used in etching experiments, 13 molecular ions CF ϩ , CF 2 ϩ , and CF 3 ϩ significantly contribute to the particulate charging and charge relaxation process. We also improve the conventional charging model by accounting for the variations of background electron number density, which inevitably accompanies the particle charge variation.…”

Section: Introductionmentioning

confidence: 86%

“…[11][12][13][14] Due to the overwhelming complexity of fluorocarbon-argon plasmas, the actual composition of the ions and radicals depends on many factors, including the kind of plasma source, the way power is coupled to the plasma, operating pressure, and gas inlet ͑proportions of C 4 F 8 and Ar͒. In the process of etching, molecular species C 4 F 8 almost completely dissociate into smaller ionic ͑superscript ''ϩ''͒ and radical ͑superscript ''0''͒ fragments, such as CF 3 ͑0,ϩ͒ , CF 2 ͑0,ϩ͒ , CF…”

Section: Formulationmentioning

confidence: 99%

Equilibrium and relaxation of particulate charge in fluorocarbon plasmas

Ostrikov

Kumar

Sugai

2001

Journal of Applied Physics

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Analysis of cathode geometry to minimize cathode erosion in direct current microplasma jet J. Appl. Phys. 112, 123302 (2012) Charging effect simulation model used in simulations of plasma etching of silicon J. Appl. Phys. 112, 084308 (2012) Extraction of negative ions from pulsed electronegative capacitively coupled plasmas J. Appl. Phys. 112, 033303 (2012) High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions J. Appl. Phys. 111, 083303 (2012) Decreasing high ion energy during transition in pulsed inductively coupled plasmas Appl. Phys. Lett. 100, 044105 (2012) Additional information on J. Appl. Phys. Charging of micron-size particulates, often appearing in fluorocarbon plasma etching experiments, is considered. It is shown that in inductively coupled and microwave slot-excited plasmas of C 4 F 8 and Ar gas mixtures, the equilibrium particle charge and charge relaxation processes are controlled by a combination of microscopic electron, atomic ͑Ar ϩ and F ϩ ͒, and molecular ion ͑CF 3 ϩ , CF 2 ϩ , and CF ϩ ͒ currents. The impact of molecular ion currents on the particulate charging and charge relaxation processes is analyzed. It is revealed that in low-power ͑Ͻ0.5 kW͒ microwave slot-excited plasmas, the impact of the combined molecular ion current to the total positive microscopic current on the particle can be as high as 40%. The particulate charge relaxation rate in fluorocarbon plasmas appears to exceed 10 8 s Ϫ1 , which is almost one order of magnitude higher than that from purely argon plasmas. This can be attributed to the impact of positive currents of fluorocarbon molecular ions, as well as to the electron density fluctuations with particle charge, associated with electron capture and release by the particulates.

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“…These problems are well addressed by using surfacewave plasma sources [7][8][9][10] based on slot antennas [4][5][6] (in what follows, we will refer to these simply as slot-antenna plasma sources). When these sources are used, it is possible to generate a downstream plasma [11] at the moderate pressures (2 to 200 Pa) that are most suitable for chemical reactions without having to discharge the substrate side with microwaves.…”

Section: Introductionmentioning

confidence: 99%

Obtaining high rates for the etching and ashing for large liquid‐crystal display substrates by using a surface‐wave plasma source

Aoki

Uekusa

Yamauchi

et al. 2004

Electron Comm Jpn Pt II

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SUMMARYIn the manufacture of thin-film transistor liquid-crystal displays (TFT-LCDs), a major goal is to scale up the production of liquid-crystal panels and lower their production costs. For that reason, we have developed a large-area high-density (3.58 × 10 11 cm -3) surface-wave plasma source based on a slot antenna. This source is designed to reduce the number of separate production steps in semiconductor processing, thereby increasing the throughput of large-area TFT-LCD substrates. We are convinced that the use of this plasma source will not only increase the etching rate, but also reduce the need for industry-standard photoresist liftoff processes by enabling an uninterrupted transition after etching to photoresist liftoff (ashing). We found that the etching rate for a 400 × 500 mm 2 polysilicon layer on a glass substrate was 58 nm/min with a uniformity of ±6.8% when our source was used. Furthermore, when ashing was carried out in the same chamber immediately after etching, the ashing rate was 1430 nm/min with a uniformity of ±9.3%. We also found that the selectivity ratio for resist versus polysilicon and the SiO 2 in an underlayer was higher than 140. This implies that our process outperforms the standard resist liftoff process; indeed, we have realized a high-uniformity etching process with twice the etching rate of standard methods. In addition, we have made progress toward realizing an ashing process, which is almost ready for practical use. These two processes can be combined into a single integrated etching-ashing process that will reduce the need for a separate liftoff procedure and simplify processing.

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Oxide Etching Using Surface Wave Coupled Plasma

Cited by 19 publications

References 9 publications

Charging and trapping of macroparticles in near-electrode regions of fluorocarbon plasmas with negative ions

Charging and trapping of macroparticles in near-electrode regions of fluorocarbon plasmas with negative ions

Equilibrium and relaxation of particulate charge in fluorocarbon plasmas

Obtaining high rates for the etching and ashing for large liquid‐crystal display substrates by using a surface‐wave plasma source

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