Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF+, CF2+, CHF2+, and CH2F+ ions

Ito, Tomoko; Karahashi, Kazuhiro; Fukasawa, Masanaga; Tatsumi, Tetsuya; Hamaguchi, Satoshi

doi:10.1116/1.3610981

Cited by 61 publications

(55 citation statements)

References 12 publications

(11 reference statements)

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“…The mass selected ion beam system [35][36][37][38][39][40][41][42][43][44] used in this study can inject mass-selected ions with a specified energy. A schematic diagram of the ion beam system is given in Fig.…”

Section: Experimental Methodsmentioning

confidence: 99%

Effects of hydrogen ion irradiation on zinc oxide etching

Hu¹,

Karahashi²,

Friederich³

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Section: Experimental Methodsmentioning

confidence: 99%

Effects of hydrogen ion irradiation on zinc oxide etching

Hu¹,

Karahashi²,

Friederich³

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…In this study, a mass-selected ion beam system [18][19][20][21][22][23][24][25] was used to investigate Ta etching processes. The beam system allows only desired ions with specified incident energy to be injected into a sample surface.…”

Section: Experimental Methodsmentioning

confidence: 99%

Suboxide/subnitride formation on Ta masks during magnetic material etching by reactive plasmas

Muraki

Karahashi

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Etching characteristics of tantalum (Ta) masks used in magnetoresistive random-access memory etching processes by carbon monoxide and ammonium (CO/NH3) or methanol (CH3OH) plasmas have been examined by mass-selected ion beam experiments with in-situ surface analyses. It has been suggested in earlier studies that etching of magnetic materials, i.e., Fe, Ni, Co, and their alloys, by such plasmas is mostly due to physical sputtering and etch selectivity of the process arises from etch resistance (i.e., low-sputtering yield) of the hard mask materials such as Ta. In this study, it is shown that, during Ta etching by energetic CO+ or N+ ions, suboxides or subnitrides are formed on the Ta surface, which reduces the apparent sputtering yield of Ta. It is also shown that the sputtering yield of Ta by energetic CO+ or N+ ions has a strong dependence on the angle of ion incidence, which suggests a correlation between the sputtering yield and the oxidation states of Ta in the suboxide or subnitride; the higher the oxidation state of Ta, the lower is the sputtering yield. These data account for the observed etch selectivity by CO/NH3 and CH3OH plasmas.

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“…The mass-selected ion beam system used in this study allows ions of specific mass to be injected into a sample surface with specified incident energy. [25][26][27][28][29][30][31][32] In this system, ions are generated in an ion source and specific ions such as Ar þ or CO þ relevant for this study are selected by the mass analyzing magnet. Ions thus extracted and selected are then injected into the surface of a sample set in the ultrahigh vacuum chamber, where the gas pressure is typically kept in the range of 10 À8 Pa. With a rotatable sample holder, the ion incident angle can be varied from 0 (i.e., normal incidence) to about 80 .…”

Section: B Mass-selected Ion Beam Systemmentioning

confidence: 99%

Correlation between dry etching resistance of Ta masks and the oxidation states of the surface oxide layers

Satake

Yamada

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Mechanisms of dry etching resistance of Ta masks, which are widely used for magnetic random access memory etching processes, have been investigated for a better understanding of their faceting characteristics. In magnetic-material etching processes by CO/NH 3 or CH 3 OH plasmas, CO þ ion is considered as one of the most dominant ion species irradiating the substrate surface. An earlier study by Li et al. [J. Vac. Sci. Technol. A 33, 040602 (2015)] has shown that the Ta sputtering yield by CO þ ion irradiation depends strongly on the ion irradiation angle and the level of the surface oxidation. In this study, the primary focus is placed on the effects of surface oxidation and physical sputtering only (without possible chemical effects of carbon) on the etching rate of Ta, and the etching characteristics of Ta and Ta 2 O 5 have been examined with Ar þ and/or oxygen ion beams. It has been found that there is a strong negative correlation between the etching rate of Ta and the oxidation states of the surface oxide layer formed during the etching process; the higher the oxidation states are, the lower the etching rate becomes. The results indicate that a strong propensity of a Ta mask to taper by irradiation of oxidizing ions (i.e., strong ion-irradiation-angle dependence of the Ta etching rate) arises from less efficient oxidation of a tapered surface by incident oxidizing ions, which enter the surface with an oblique angle. V

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Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF+, CF2+, CHF2+, and CH2F+ ions

Cited by 61 publications

References 12 publications

Effects of hydrogen ion irradiation on zinc oxide etching

Effects of hydrogen ion irradiation on zinc oxide etching

Suboxide/subnitride formation on Ta masks during magnetic material etching by reactive plasmas

Correlation between dry etching resistance of Ta masks and the oxidation states of the surface oxide layers

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