<i>In situ</i> x-ray absorption near-edge structure analysis for extreme ultraviolet lithography projection optics contamination

et al. 2011

Jpn. J. Appl. Phys.

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The state-selective dissociation dynamics for anionic and excited neutral fragments of gaseous SiCl 4 following Cl 2p and Si 2p core-level excitations were characterized by combining measurements of the photoninduced anionic dissociation, x-ray absorption and UV/visible dispersed fluorescence. The transitions of core electrons to high Rydberg states/doubly excited states in the vicinity of both Si 2p and Cl 2p ionization thresholds of gaseous SiCl 4 lead to a remarkably enhanced production of anionic, Si − and Cl − , fragments and excited neutral atomic, Si * , fragments. This enhancement via core-level excitation near the ionization threshold of gaseous SiCl 4 is explained in terms of the contributions from the Auger decay of doubly excited states, shake-modified resonant Auger decay, or/and post-collision interaction. These complementary results provide insight into the state-selective anionic and excited neutral fragmentation of gaseous molecules via core-level excitation.

Section: Methodsmentioning

confidence: 99%

Nonlinear Behavior of Decrease in Reflectivity of Multilayer Mirrors for Extreme Ultraviolet Lithography Optics by High-Flux Extreme Ultraviolet Irradiation in Various Vacuum Environments

Niibe

et al. 2011

Jpn. J. Appl. Phys.

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“…11 The amount of the increase and decrease of the carbon and oxygen on the mirror surface by EUV irradiation was determined by acquiring the absorption edge intensities of carbon, which was about 285 eV, and that of oxygen, which was about 530 eV. The high-resolution monochromator is equipped in the beamline, and the soft x-ray absorption spectrum ͑SXAS͒ is obtained as the total electron yield mode by scanning the photon energy onto the sample.…”

Section: Methodsmentioning

confidence: 99%

“…2; this map was taken in situ as a distribution of the soft x-ray absorption intensity at the C K absorption edge. 11,12 The EUV dose dependence of the reflectivity changes of Ru-capped Mo/ Si multilayer mirrors at the irradiation center for n-decane introduction is shown in Fig. 2 is the EUV irradiation area.…”

Section: A Protection Of Surface Oxidation By Hydrocarbon Gasesmentioning

confidence: 99%

“…Therefore, research and development of a contamination prevention mechanism are being conducted at many research laboratories. 11 Using this system, we recently learned that the introduction of a small amount of ethanol prevented the surface oxidation of the mirror even in a high water-vapor-pressure atmosphere, in which surface oxidation occurs for a Ru-capped multilayer. 7 It is important to develop an oxidation prevention mechanism because removing oxide was considered to be very difficult.…”

Section: Introductionmentioning

confidence: 99%

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Protection and reduction of surface oxidation of Mo∕Si multilayers for extreme ultraviolet lithography projection optics by control of hydrocarbon gas atmosphere

Niibe

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

2008

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Articles you may be interested inEffect of interface treatment with assisted ion beam on Mo-Si multilayer formation for mask blanks for extreme ultraviolet lithographyCleaning of extreme ultraviolet lithography optics and masks using 13.5 nm and 172 nm radiation Influence of glass substrate surface roughness on extreme ultraviolet reflectivity of Mo ∕ Si multilayer To protect the surface oxidation of Mo/ Si multilayer films by extreme ultraviolet ͑EUV͒ irradiation under a vacuum atmosphere with residual water, two experiments were carried out. One consisted of examining the oxidation protection effect for isopropyl alcohol ͑IPA͒ and n-decane gases. The reflectivity change of the Ru-capped multilayer film by EUV irradiation was investigated under a vacuum atmosphere with residual water vapor at a pressure of 1.3ϫ 10 −5 Pa, and, in addition, each hydrocarbon ͑HC͒ gas was introduced by changing its pressure. A protective effect against oxidation was observed in both gases when introduced at a pressure in the order of 10 −6 Pa. For IPA, no remarkable decrease in the reflectivity was observed even when the introductory pressure was raised to the order of 10 −4 Pa. However, for n-decane, the reflectivity decreased remarkably when pressure in the order of 10 −5 Pa was introduced. The other experiment consisted of examining the reduction effect of the oxidized surface by EUV irradiation when introducing HC gas. Ru-and Si-capped multilayers were once oxidized by EUV irradiation under a water vapor atmosphere. However, for the Ru-capped multilayer, the reflectivity was recovered when EUV was irradiated in the presence of ethanol gas at a pressure of 3.8ϫ 10 −5 Pa. The oxide layer of the Ru cap was reduced at this time.

“…The measurement of the elemental concentration map of the sample surface was carried out in situ. The details of the mapping technique using X-ray absorption spectroscopy (XAS) have been reported elsewhere [5]. The sample holder in the center of the main chamber was electrically insulated from the main chamber.…”

Section: Contamination Evaluation Systemmentioning

confidence: 99%

Protection from surface oxidation of Ru capping layers for EUVL projection optics mirrors by introducing hydrocarbon gas

Niibe²,

et al. 2008

SPIE Proceedings

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We investigated the protection of a Ru-capped Mo/Si multilayer from surface oxidation under exposure to EUV radiation in the presence of water vapor and isopropyl alcohol (IPA). Degradation of the reflectance of the Ru-capped Mo/Si multilayer by EUV irradiation was controlled by introducing IPA gas. We also investigated the reduction effect of the oxide layer in a multilayer mirror by introducing ethanol and exposed EUV. The Ru-capped multilayer sample was exposed to EUV radiation in the presence of only water vapor to oxidize its surface. The reflectance decreased by about 1.5%. Then the sample was exposed to EUV radiation in the presence of only ethanol vapor. The reflectivity of the sample was recovered to +0.5%, and the atomic concentration of oxygen in the irradiated area was decreased by EUV irradiation in the presence of ethanol.