Energy distribution functions for ions from pulsed EUV-induced plasmas in low pressure N2-diluted H2 gas

Job Beckers (Corresponding author), Tijn van de Ven, C.A. de Meijere, Ruud van der Horst, M. van Kampen, Vadim Banine

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

The operation of Extreme Ultraviolet (EUV) lithography scanners inherently goes hand-in-hand with the creation of highly transient pulsed plasmas in the optical path of these tools. These so-called EUV-induced plasmas are created upon photoionization events when a pulsed beam of EUV photons travels through the low pressure background gas. It is fully recognized by the lithography industry that EUV-induced plasmas may significantly impact the quality and life-time of expensive and delicate optical elements in the scanner. Research efforts into EUV-induced plasmas impacting plasma-facing surfaces have so far been limited to pure hydrogen (H2) plasmas. However, this hydrogen background gas may occasionally be diluted with a small fraction of another molecular gas such as nitrogen (N2). The impact on the relevant plasma parameters of such molecular contaminants has remained unknown until now. In this letter, we put forward measurements of energy-resolved fluxes of (positive) hydrogen ions, nitrogen ions, and hydrogen-nitrogen ions created in a pulsed N2-diluted EUV-induced plasma in H2 at approximately 5 Pa (typical EUV lithography scanner conditions). The data have been obtained using an electrostatic quadrupole plasma analyzer and show that although the N2-dilution fraction is small (∼2 × 10−3) compared to the H2 partial pressure, implications for the ion flux out of the plasma and the composition thereof are significant. Since the mass of nitrogen-containing ions is much higher in comparison to that of their hydrogen counterparts, and because of their potential chemical activity, this effect has to be taken into account while studying the surface impact of EUV-induced plasmas.
Original languageEnglish
Article number133502
Number of pages5
JournalApplied Physics Letters
Volume114
Issue number13
DOIs
Publication statusPublished - 2 Apr 2019

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energy distribution
low pressure
distribution functions
gases
ions
nitrogen ions
scanners
lithography
hydrogen ions
plasma composition
hydrogen plasma
hydrogen
molecular gases
optical paths
positive ions
travel
contaminants
partial pressure
dilution
photoionization

Cite this

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title = "Energy distribution functions for ions from pulsed EUV-induced plasmas in low pressure N2-diluted H2 gas",
abstract = "The operation of Extreme Ultraviolet (EUV) lithography scanners inherently goes hand-in-hand with the creation of highly transient pulsed plasmas in the optical path of these tools. These so-called EUV-induced plasmas are created upon photoionization events when a pulsed beam of EUV photons travels through the low pressure background gas. It is fully recognized by the lithography industry that EUV-induced plasmas may significantly impact the quality and life-time of expensive and delicate optical elements in the scanner. Research efforts into EUV-induced plasmas impacting plasma-facing surfaces have so far been limited to pure hydrogen (H2) plasmas. However, this hydrogen background gas may occasionally be diluted with a small fraction of another molecular gas such as nitrogen (N2). The impact on the relevant plasma parameters of such molecular contaminants has remained unknown until now. In this letter, we put forward measurements of energy-resolved fluxes of (positive) hydrogen ions, nitrogen ions, and hydrogen-nitrogen ions created in a pulsed N2-diluted EUV-induced plasma in H2 at approximately 5 Pa (typical EUV lithography scanner conditions). The data have been obtained using an electrostatic quadrupole plasma analyzer and show that although the N2-dilution fraction is small (∼2 × 10−3) compared to the H2 partial pressure, implications for the ion flux out of the plasma and the composition thereof are significant. Since the mass of nitrogen-containing ions is much higher in comparison to that of their hydrogen counterparts, and because of their potential chemical activity, this effect has to be taken into account while studying the surface impact of EUV-induced plasmas.",
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Energy distribution functions for ions from pulsed EUV-induced plasmas in low pressure N2-diluted H2 gas. / Beckers, Job (Corresponding author); van de Ven, Tijn; de Meijere, C.A. ; van der Horst, Ruud; van Kampen, M.; Banine, Vadim.

In: Applied Physics Letters, Vol. 114, No. 13, 133502, 02.04.2019.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Energy distribution functions for ions from pulsed EUV-induced plasmas in low pressure N2-diluted H2 gas

AU - Beckers, Job

AU - van de Ven, Tijn

AU - de Meijere, C.A.

AU - van der Horst, Ruud

AU - van Kampen, M.

AU - Banine, Vadim

PY - 2019/4/2

Y1 - 2019/4/2

N2 - The operation of Extreme Ultraviolet (EUV) lithography scanners inherently goes hand-in-hand with the creation of highly transient pulsed plasmas in the optical path of these tools. These so-called EUV-induced plasmas are created upon photoionization events when a pulsed beam of EUV photons travels through the low pressure background gas. It is fully recognized by the lithography industry that EUV-induced plasmas may significantly impact the quality and life-time of expensive and delicate optical elements in the scanner. Research efforts into EUV-induced plasmas impacting plasma-facing surfaces have so far been limited to pure hydrogen (H2) plasmas. However, this hydrogen background gas may occasionally be diluted with a small fraction of another molecular gas such as nitrogen (N2). The impact on the relevant plasma parameters of such molecular contaminants has remained unknown until now. In this letter, we put forward measurements of energy-resolved fluxes of (positive) hydrogen ions, nitrogen ions, and hydrogen-nitrogen ions created in a pulsed N2-diluted EUV-induced plasma in H2 at approximately 5 Pa (typical EUV lithography scanner conditions). The data have been obtained using an electrostatic quadrupole plasma analyzer and show that although the N2-dilution fraction is small (∼2 × 10−3) compared to the H2 partial pressure, implications for the ion flux out of the plasma and the composition thereof are significant. Since the mass of nitrogen-containing ions is much higher in comparison to that of their hydrogen counterparts, and because of their potential chemical activity, this effect has to be taken into account while studying the surface impact of EUV-induced plasmas.

AB - The operation of Extreme Ultraviolet (EUV) lithography scanners inherently goes hand-in-hand with the creation of highly transient pulsed plasmas in the optical path of these tools. These so-called EUV-induced plasmas are created upon photoionization events when a pulsed beam of EUV photons travels through the low pressure background gas. It is fully recognized by the lithography industry that EUV-induced plasmas may significantly impact the quality and life-time of expensive and delicate optical elements in the scanner. Research efforts into EUV-induced plasmas impacting plasma-facing surfaces have so far been limited to pure hydrogen (H2) plasmas. However, this hydrogen background gas may occasionally be diluted with a small fraction of another molecular gas such as nitrogen (N2). The impact on the relevant plasma parameters of such molecular contaminants has remained unknown until now. In this letter, we put forward measurements of energy-resolved fluxes of (positive) hydrogen ions, nitrogen ions, and hydrogen-nitrogen ions created in a pulsed N2-diluted EUV-induced plasma in H2 at approximately 5 Pa (typical EUV lithography scanner conditions). The data have been obtained using an electrostatic quadrupole plasma analyzer and show that although the N2-dilution fraction is small (∼2 × 10−3) compared to the H2 partial pressure, implications for the ion flux out of the plasma and the composition thereof are significant. Since the mass of nitrogen-containing ions is much higher in comparison to that of their hydrogen counterparts, and because of their potential chemical activity, this effect has to be taken into account while studying the surface impact of EUV-induced plasmas.

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M3 - Article

VL - 114

JO - Applied Physics Letters

JF - Applied Physics Letters

SN - 0003-6951

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M1 - 133502

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