Molecular contamination mitigation in EUVL by environmental control

Norbert Koster; Bas Mertens; Rik Jansen; Annemieke Van De Runstraat; Frank Stietz; Marco Wedowski; Hans Meiling; Roman Klein; Alexander Gottwald; Frank Scholze; Matthieu Visser; Ralph Kurt; Peer Zalm; Eric Louis; Andrey Yakshin

doi:10.1016/S0167-9317(02)00535-X

Molecular contamination mitigation in EUVL by environmental control

Norbert Koster^*, Bas Mertens, Rik Jansen, Annemieke Van De Runstraat, Frank Stietz, Marco Wedowski, Hans Meiling, Roman Klein, Alexander Gottwald, Frank Scholze, Matthieu Visser, Ralph Kurt, Peer Zalm, Eric Louis, Andrey Yakshin

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › Academic › peer-review

45 Citations (Scopus)

Abstract

EUVL tools operate under vacuum conditions to avoid absorption losses. Under these conditions, the MoSi multilayer mirrors are contaminated, resulting in reduced reflection and thus throughput. We report on experiments on MoSi mirrors exposed to EUV radiation from a synchrotron. To mimic the effects of EUV radiation we also exposed samples using an electron gun. The oxidation rate was found to be ∼0.016 nm/h per mW/mm² of EUV radiation under conditions expected for a high throughput EUVL system. This oxidation can to a large extent be suppressed by using smart gas blend strategies during exposure, e.g. using ethanol. A carbon growth rate of 0.25 nm/h was found for a hydrocarbon pressure of 10^-9 mbar Fomblin. We demonstrate that carbonisation can be suppressed by admitting oxygen during electron gun exposure.

Original language	English
Pages (from-to)	65-76
Number of pages	12
Journal	Microelectronic engineering
Volume	61-62
DOIs	https://doi.org/10.1016/S0167-9317(02)00535-X
Publication status	Published - 1 Jul 2002
Externally published	Yes
Event	Micro and Nano Engineering, MNE 2001 - Grenoble, France Duration: 16 Sept 2001 → 19 Sept 2001

Keywords

Carbon growth
Contamination
EUVL
Mirror lifetime
MoSi mirrors
Oxidation
Reflection loss

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10.1016/S0167-9317(02)00535-X

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title = "Molecular contamination mitigation in EUVL by environmental control",

abstract = "EUVL tools operate under vacuum conditions to avoid absorption losses. Under these conditions, the MoSi multilayer mirrors are contaminated, resulting in reduced reflection and thus throughput. We report on experiments on MoSi mirrors exposed to EUV radiation from a synchrotron. To mimic the effects of EUV radiation we also exposed samples using an electron gun. The oxidation rate was found to be ∼0.016 nm/h per mW/mm2 of EUV radiation under conditions expected for a high throughput EUVL system. This oxidation can to a large extent be suppressed by using smart gas blend strategies during exposure, e.g. using ethanol. A carbon growth rate of 0.25 nm/h was found for a hydrocarbon pressure of 10-9 mbar Fomblin. We demonstrate that carbonisation can be suppressed by admitting oxygen during electron gun exposure.",

keywords = "Carbon growth, Contamination, EUVL, Mirror lifetime, MoSi mirrors, Oxidation, Reflection loss",

author = "Norbert Koster and Bas Mertens and Rik Jansen and \{Van De Runstraat\}, Annemieke and Frank Stietz and Marco Wedowski and Hans Meiling and Roman Klein and Alexander Gottwald and Frank Scholze and Matthieu Visser and Ralph Kurt and Peer Zalm and Eric Louis and Andrey Yakshin",

year = "2002",

month = jul,

day = "1",

doi = "10.1016/S0167-9317(02)00535-X",

language = "English",

volume = "61-62",

pages = "65--76",

journal = "Microelectronic engineering",

issn = "0167-9317",

publisher = "Elsevier B.V.",

note = "Micro and Nano Engineering, MNE 2001, MNE 2001 ; Conference date: 16-09-2001 Through 19-09-2001",

}

TY - JOUR

T1 - Molecular contamination mitigation in EUVL by environmental control

AU - Koster, Norbert

AU - Mertens, Bas

AU - Jansen, Rik

AU - Van De Runstraat, Annemieke

AU - Stietz, Frank

AU - Wedowski, Marco

AU - Meiling, Hans

AU - Klein, Roman

AU - Gottwald, Alexander

AU - Scholze, Frank

AU - Visser, Matthieu

AU - Kurt, Ralph

AU - Zalm, Peer

AU - Louis, Eric

AU - Yakshin, Andrey

PY - 2002/7/1

Y1 - 2002/7/1

N2 - EUVL tools operate under vacuum conditions to avoid absorption losses. Under these conditions, the MoSi multilayer mirrors are contaminated, resulting in reduced reflection and thus throughput. We report on experiments on MoSi mirrors exposed to EUV radiation from a synchrotron. To mimic the effects of EUV radiation we also exposed samples using an electron gun. The oxidation rate was found to be ∼0.016 nm/h per mW/mm2 of EUV radiation under conditions expected for a high throughput EUVL system. This oxidation can to a large extent be suppressed by using smart gas blend strategies during exposure, e.g. using ethanol. A carbon growth rate of 0.25 nm/h was found for a hydrocarbon pressure of 10-9 mbar Fomblin. We demonstrate that carbonisation can be suppressed by admitting oxygen during electron gun exposure.

AB - EUVL tools operate under vacuum conditions to avoid absorption losses. Under these conditions, the MoSi multilayer mirrors are contaminated, resulting in reduced reflection and thus throughput. We report on experiments on MoSi mirrors exposed to EUV radiation from a synchrotron. To mimic the effects of EUV radiation we also exposed samples using an electron gun. The oxidation rate was found to be ∼0.016 nm/h per mW/mm2 of EUV radiation under conditions expected for a high throughput EUVL system. This oxidation can to a large extent be suppressed by using smart gas blend strategies during exposure, e.g. using ethanol. A carbon growth rate of 0.25 nm/h was found for a hydrocarbon pressure of 10-9 mbar Fomblin. We demonstrate that carbonisation can be suppressed by admitting oxygen during electron gun exposure.

KW - Carbon growth

KW - Contamination

KW - EUVL

KW - Mirror lifetime

KW - MoSi mirrors

KW - Oxidation

KW - Reflection loss

UR - https://www.scopus.com/pages/publications/0036643631

U2 - 10.1016/S0167-9317(02)00535-X

DO - 10.1016/S0167-9317(02)00535-X

M3 - Conference article

AN - SCOPUS:0036643631

SN - 0167-9317

VL - 61-62

SP - 65

EP - 76

JO - Microelectronic engineering

JF - Microelectronic engineering

T2 - Micro and Nano Engineering, MNE 2001

Y2 - 16 September 2001 through 19 September 2001

ER -

Molecular contamination mitigation in EUVL by environmental control

Abstract

Keywords

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