Linewidth uniformity versus etch rate uniformity in refractory metal plasma etching

Sami Franssila

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Etch rate, etch rate uniformity, linewidth uniformity, and microloading in tungsten, molybdenum, and niobium plasma etching have been studied. Electrical linewidth data with typically 100–300 measured lines/wafer have been used. Relation between linewidth uniformity and etched depth uniformity (as measured by profilometer) has been explored. Effects of tungsten film deposition processes (oxygen contamination) have been studied. Tungsten etch rate maximum in SF6/O2 is at 85/15 ratio for the oxygen contaminated films, but higher oxygen percentage in SF6/O2 is required for maximum etch rate of pure films. Oxygen impurities in the tungsten film affect the etch rate but neither linewidth nor linewidth uniformity. In molybdenum etching in Cl2/O2 plasma the etched depth uniformity gives an overly pessimistic uniformity value even though linewidth uniformity is acceptable 12% (3σ). Addition of 3%–6% of CHF3 to Cl2/O2 is shown to change microloading characteristics and to improve linewidth uniformity. On 100 mm wafers, 6%–12% (3σ) linewidth uniformities were obtained for the different metals. Linewidth differences between isolated and array lines were 4%–8%.
Original languageEnglish
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume12
Issue number5
DOIs
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

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Refractory metals
Plasma etching
Linewidth
Tungsten
Oxygen
Molybdenum
Niobium
Etching
Contamination
Impurities
Plasmas

Cite this

@article{43899c22e8384bcf80c611c65ccd00b2,
title = "Linewidth uniformity versus etch rate uniformity in refractory metal plasma etching",
abstract = "Etch rate, etch rate uniformity, linewidth uniformity, and microloading in tungsten, molybdenum, and niobium plasma etching have been studied. Electrical linewidth data with typically 100–300 measured lines/wafer have been used. Relation between linewidth uniformity and etched depth uniformity (as measured by profilometer) has been explored. Effects of tungsten film deposition processes (oxygen contamination) have been studied. Tungsten etch rate maximum in SF6/O2 is at 85/15 ratio for the oxygen contaminated films, but higher oxygen percentage in SF6/O2 is required for maximum etch rate of pure films. Oxygen impurities in the tungsten film affect the etch rate but neither linewidth nor linewidth uniformity. In molybdenum etching in Cl2/O2 plasma the etched depth uniformity gives an overly pessimistic uniformity value even though linewidth uniformity is acceptable 12{\%} (3σ). Addition of 3{\%}–6{\%} of CHF3 to Cl2/O2 is shown to change microloading characteristics and to improve linewidth uniformity. On 100 mm wafers, 6{\%}–12{\%} (3σ) linewidth uniformities were obtained for the different metals. Linewidth differences between isolated and array lines were 4{\%}–8{\%}.",
author = "Sami Franssila",
year = "1994",
doi = "10.1116/1.587543",
language = "English",
volume = "12",
journal = "Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics",
issn = "2166-2746",
publisher = "AVS Science and Technology Society",
number = "5",

}

Linewidth uniformity versus etch rate uniformity in refractory metal plasma etching. / Franssila, Sami.

In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 12, No. 5, 1994.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Linewidth uniformity versus etch rate uniformity in refractory metal plasma etching

AU - Franssila, Sami

PY - 1994

Y1 - 1994

N2 - Etch rate, etch rate uniformity, linewidth uniformity, and microloading in tungsten, molybdenum, and niobium plasma etching have been studied. Electrical linewidth data with typically 100–300 measured lines/wafer have been used. Relation between linewidth uniformity and etched depth uniformity (as measured by profilometer) has been explored. Effects of tungsten film deposition processes (oxygen contamination) have been studied. Tungsten etch rate maximum in SF6/O2 is at 85/15 ratio for the oxygen contaminated films, but higher oxygen percentage in SF6/O2 is required for maximum etch rate of pure films. Oxygen impurities in the tungsten film affect the etch rate but neither linewidth nor linewidth uniformity. In molybdenum etching in Cl2/O2 plasma the etched depth uniformity gives an overly pessimistic uniformity value even though linewidth uniformity is acceptable 12% (3σ). Addition of 3%–6% of CHF3 to Cl2/O2 is shown to change microloading characteristics and to improve linewidth uniformity. On 100 mm wafers, 6%–12% (3σ) linewidth uniformities were obtained for the different metals. Linewidth differences between isolated and array lines were 4%–8%.

AB - Etch rate, etch rate uniformity, linewidth uniformity, and microloading in tungsten, molybdenum, and niobium plasma etching have been studied. Electrical linewidth data with typically 100–300 measured lines/wafer have been used. Relation between linewidth uniformity and etched depth uniformity (as measured by profilometer) has been explored. Effects of tungsten film deposition processes (oxygen contamination) have been studied. Tungsten etch rate maximum in SF6/O2 is at 85/15 ratio for the oxygen contaminated films, but higher oxygen percentage in SF6/O2 is required for maximum etch rate of pure films. Oxygen impurities in the tungsten film affect the etch rate but neither linewidth nor linewidth uniformity. In molybdenum etching in Cl2/O2 plasma the etched depth uniformity gives an overly pessimistic uniformity value even though linewidth uniformity is acceptable 12% (3σ). Addition of 3%–6% of CHF3 to Cl2/O2 is shown to change microloading characteristics and to improve linewidth uniformity. On 100 mm wafers, 6%–12% (3σ) linewidth uniformities were obtained for the different metals. Linewidth differences between isolated and array lines were 4%–8%.

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JO - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics

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SN - 2166-2746

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