Study of ruthenium-capped multilayer mirror for EUV irradiation durability

Takase, Hiromitsu; Terashima, Shigeru; Gomei, Yoshio; Tanabe, Mitsuaki; Watanabe, Yutaka; Aoki, Takashi; Murakami, Katsuhiko; Matsunari, Shuichi; Niibe, Masahito; Kakutani, Yukinobu

doi:10.1117/12.657089

Cited by 9 publications

(6 citation statements)

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“…These data suggest that EUV reflectivity reduces as a function of the applied radiation energy, not the photon energy. This is in agreement with previous studies of radiation damage on Ru cap ML film [2,4,5,7]. The EUV reflectivity dropped after exposure to radiation and was not changed by the multiple cleaning and exposure to different chemistries.…”

Section: Ru Surface Modification By Single Radiation and Multiple Chesupporting

confidence: 93%

“…Finally, the surface of the capping layer can also be exposed to plasma radiations during manufacturing processes. The exposure impact on the reflectivity of the Ru cap blank has been previously reported [2][3][4][5][6][7]. However, in a recent study [8], we observed that interaction of chemicals with the Ru cap surface during mask cleaning depends on the exposure of this surface to the radiation.…”

Section: Introductionmentioning

confidence: 59%

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Effect of radiation on the defectivity and stability of Ru-capped MoSi multilayer blanks

Rastegar¹,

Durkaya²,

Cepler³

et al. 2012

SPIE Proceedings

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During their usage and fabrication, EUV masks are exposed to light radiation from λ=13.5 nm up to infrared wavelengths. During EUV exposure, masks are not only exposed to 13.5 nm radiation but also to out-of-band radiation which expands from λ=140 to 600 nm for a long period of time. The mask surface is also exposed to different chemicals during cleaning processes, depending on the usage of the mask. During its effective life, an EUV mask should undergo many cycles of cleaning and radiation. Consequently, the Ru surface is modified by photon energy (wavelength) as well as number of photons (intensity and energy). This modified Ru surface will react with chemicals in different ways. Exposure to 172 nm light followed by Ammonium Hydroxide/ Hydrogen peroxide/ water mixture (APM) will result in 0.5% loss of EUV light while 172nm light exposure followed by Sulfuric acid /Hydrogen peroxide mixture (SPM) will reduce EUV reflectivity by 3%. Higher radiation energy on the order of 200 Joules will damage the Ru surface and cause increased defectivity at the mask surface. In addition, higher radiation energies will result in thermal effects such as formation of Ru silicide and Mo silicide. Ru oxidation valence also depends on the radiation power and radiation wavelength. In the absence of radiation or low energy radiation, RuO 3 is preferred oxidation state but RuO is preferred in the higher radiation energies. Comparison between 532 nm and 1064 nm radiation showed that RuO 2 is the preferred oxidation state at a wavelength of 532 nm, despite much lower radiation power.

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Section: Ru Surface Modification By Single Radiation and Multiple Chesupporting

confidence: 93%

Section: Introductionmentioning

confidence: 59%

Effect of radiation on the defectivity and stability of Ru-capped MoSi multilayer blanks

Rastegar¹,

Durkaya²,

Cepler³

et al. 2012

SPIE Proceedings

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“…Table 1 shows characteristics of both the EUV beamlines. Experimental data of carbon deposition rate at SBL-2 and reflectivity change at BL9 have been reported in detail in previous papers [1][2][3][4] . ________________________________________________________________________ *nakayama.takahiro003@canon.co.jp; phone +81-28-6675711; fax +81-28-667-5334…”

Section: Experimental Apparatusmentioning

confidence: 97%

“…We have to elucidate a photochemical reaction of EUV irradiation to the MLMs and estimate carbon deposition rate for HVM. We found that carbon deposition rate is not proportional to average EUV intensity and hydrocarbon partial pressure [3][4] . But we do not know dependences of carbon deposition rate on characteristics of EUV source.…”

Section: Introductionmentioning

confidence: 97%

Analysis of carbon deposition on multilayer mirrors by using two different beamlines

Nakayama

Miyake

Takase

et al. 2009

Alternative Lithographic Technologies

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It is very important to mitigate oxidation of multilayer mirrors (MLMs) and carbon deposition onto MLMs to extend the lifetime of EUV exposure tool. In order to estimate the lifetime, we have to figure out scaling law. Previous results at EUVA have shown that carbon deposition rate on MLMs is not proportional to every hydrocarbon partial pressure and every EUV intensity 3-4 . In this study we focused on carbon deposition on Si-capped multilayer mirror. We made experiments of EUV irradiation to the MLMs using two different apparatuses. One is connected to a beamline (SBL-2) of synchrotron radiation facility Super-ALIS in the NTT Atsugi research and development center, and the other is connected to a beamline (BL9) of synchrotron radiation facility New SUBARU in the University of Hyogo. As the result of experiments, we found that different carbon deposition rate occurred on the different beamlines, although they have the same average EUV intensity. We present differences of carbon deposition rate on MLMs between two different beamlines and estimation of carbon deposition rate on EUV tool analyzing dependences of carbon deposition rate on characteristics of EUV source.

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“…Most components of the Beam Line (left) are copied from the current beam line. EBL2 will be suited for characterizing and analysing phenomena such as carbon growth on EUV masks [13], oxidation of multilayer optics [14], as well as investigating the physics and effects of EUV-induced plasmas.…”

Section: System Designmentioning

confidence: 99%

A new mask exposure and analysis facility

et al. 2014

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The introduction of ever higher source powers in EUV systems causes increased risks for contamination and degradation of EUV masks and pellicles. Appropriate testing can help to inventory and mitigate these risks. To this end, we propose EBL2: a laboratory EUV exposure system capable of operating at high EUV powers and intensities, and capable of exposing and analyzing EUV masks. The proposed system architecture is similar to the EBL system which has been operated jointly by TNO and Carl Zeiss SMT since 2005. EBL2 contains an EUV Beam Line, in which samples can be exposed to EUV irradiation in a controlled environment. Attached to this Beam Line is an XPS system, which can be reached from the Beam Line via an in-vacuum transfer system. This enables surface analysis of exposed masks without breaking vacuum. Automated handling with dual pods is foreseen so that exposed EUV masks will still be usable in EUV lithography tools to assess the imaging impact of the exposure. Compared to the existing system, large improvements in EUV power, intensity, reliability, and flexibility are proposed. Also, in-situ measurements by e.g. ellipsometry is foreseen for real time monitoring of the sample condition. The system shall be equipped with additional ports for EUVR or other analysis tools. This unique facility will be open for external customers and other research groups.

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Study of ruthenium-capped multilayer mirror for EUV irradiation durability

Cited by 9 publications

References 0 publications

Effect of radiation on the defectivity and stability of Ru-capped MoSi multilayer blanks

Effect of radiation on the defectivity and stability of Ru-capped MoSi multilayer blanks

Analysis of carbon deposition on multilayer mirrors by using two different beamlines

A new mask exposure and analysis facility

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