Progress in EUV optics lifetime expectations

Mertens, Bas; Weiß, Markus; Meiling, H.; Klein, R.; Louis, Eric; Kurt, R.; Wedowski, Marco; Trenkler, Hans; Wolschrijn, B. T.; Jansen, R.; Runstraat, A. van de; Moors, Roel; Spee, Karel; Plöger, Sven; Kruijs, Robbert van de

doi:10.1016/j.mee.2004.02.009

Cited by 12 publications

(17 citation statements)

References 2 publications

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“…[1] In this application, it is crucial to prevent oxidation, as oxidation leads to irreversible loss of reflection. [2,3] For developing methods to reduce the loss of reflection in EUV lithography applications, the formation and initial growth of oxide needs to be understood. RuO 2 is the only known stable oxide of Ru at room temperature up to 900 K. [4] Above this temperature, volatile RuO 4 will form.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the oxidation of Ru using XPS

Ernst

Sloof

2008

Surface & Interface Analysis

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A method is presented to analyze XPS spectra recorded from thin (<5 nm) oxide layers with known thickness on corresponding metal substrates. With this method, the contribution of the oxide overlayer can be separated from the metal substrate for the metal core level line, even when the difference in binding energy between metallic and oxidic electrons is small. This method involves the fitting of Doniach-Sunjic (DS) line shapes for the metallic and oxidic state to the measured spectrum, where the area ratio between the metallic and oxidic contribution is fixed through the known thickness.The method was applied to ruthenium single crystals with a (0001) surface that were oxidized in a ultra-high vacuum (UHV) chamber at a temperature of 673 K and an oxygen pressure between 1×10 −4 and 1×10 −2 Pa. Analysis of the oxidic contribution to the Ru 3p 3/2 line shows that two different types of oxides can be formed in the oxidation process.

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Section: Introductionmentioning

confidence: 99%

Unraveling the oxidation of Ru using XPS

Ernst

Sloof

2008

Surface & Interface Analysis

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“…In (U)HV systems, the contamination-precursor mix often comprises volatile (mass < 100 amu) and non-volatile (mass > 100 amu) hydrocarbons [3]. The heavier hydrocarbons reside considerably longer on a surface [6][7][8], and hence are much more effectively dissociated when irradiated by an EUV [2,3], or scanning electron beam [5]. To prevent and control surface contamination, it is necessary to quantify and monitor the partial pressure of non-volatile hydrocarbons [1].…”

Section: Surface Contaminationmentioning

confidence: 99%

“…Both vacuum system parts and samples are potential contaminant sources. Extremely low partial pressures (1E-15 -1E-11 mbar) of contaminants can already kill yield [2,3]. The annual cost per 1% yield loss is estimated at 100 M$ per fab [4].…”

Section: Introductionmentioning

confidence: 99%

Lab- and field-test results of MFIG, the first real-time vacuum-contamination sensor

et al. 2017

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To produce high-end semiconductor products, clean vacuum is often required. Even small amounts of high-mass molecules can reduce product yield. The challenge is to timely detect the presence of relevant contaminants. This is where MFIG can help. The mass-filtered ion gauge sensor (MFIG) continuously and selectively monitors the presence of high-mass contaminant molecules with a sensitivity down to 1E-13 mbar at total pressures up to 1E-5 mbar.This contribution presents laboratory and field-test data to demonstrate the capabilities of the latest version of the MFIG sensor in continuously and selectively detecting high-mass contaminant molecules in (U)HV vacuum.

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“…The practical usability of such optics depends on their lifetime, which can be reduced by several degradation processes [95][96][97][98][99]. In particular, we distinguish degradation due to surface phenomena and internal changes to the ML structure.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, we distinguish degradation due to surface phenomena and internal changes to the ML structure. Surface phenomena include sidewall contamination due to the fabrication process or the cracking of hydrocarbons, for instance from photoresist or cables in the vacuum system holding the ML mirror [96,97,100,101]. The contamination results in additional absorption and hence reduces peak reflectivity of LMGs.…”

Section: Introductionmentioning

confidence: 99%

Single-order lamellar multilayer gratings

Meer¹

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Cover: 3D artist impression of a Lamellar Multilayer Grating (LMG). A Transmission Electron Microscope image of an actual LMG is shown on the rear. The grating was etched into a 400 bi-layer W/Si multilayer mirror with a total stack height H of 1 μm and a tungsten layer thickness of only 3 atoms. The grating had a period D of 300 nm and a lamel width ΓD of 75 nm. In comparison to the TEM image on the rear, the red and green layers in the artist impression correspond to tungsten and silicon, respectively. The bi-layer period in the artist impression is overestimated by a factor of 10 for visibility. SummaryA major challenge in the soft x-ray (SXR) and eXtreme UltraViolet (XUV) spectral ranges is the ability to manipulate the incident radiation using optical elements. By patterning conventional multilayer mirrors with nanoscale structures, novel optical elements with a variety of optical properties can be obtained. In this work, the design, fabrication and characterization of Lamellar Multilayer Gratings (LMG) was investigated. Such LMGs are a particular form of the general class of Bragg-Fresnel optics which combine Fresnel optics with Bragg reflection to provide unique dispersive and focusing optics. In particular, LMGs can be used to improve the spectral resolution of x-ray fluorescence techniques.A Coupled Waves Approach (CWA) was derived to simulate the optical performance, in terms of resolution and reflectivity, of LMGs. This CWA allowed to study the physical principles behind LMGs and resulted in the identification of an optimal LMG operating regime. In this regime, the incident beam is reflected in a single diffraction order and is hence referred to as the singleorder regime. Such single-order LMGs were fabricated using UV-NanoImprint Lithography and Bosch Deep Reactive Ion Etching, a process chosen to enable rapid practical development. Single-order operation was experimentally demonstrated and showed an improvement in spectral resolution of a factor of 3.8 with regard to conventional multilayer mirrors. Singe-order excitation of higher diffraction orders was also measured and analyzed.Single-order operation often requires multilayer stacks and grating structures that cannot be fabricated with sufficient accuracy using current technologies. As this invalidates the semi-infinite multilayer approximation, we investigated the optical performance of LMGs with finite multilayer stacks. We determined the ratio between the absorber thickness and bi-layer period of the multilayer stack can be used to further tailor LMG optical performance to maximize bandwidth reduction or minimize peak reflectivity loss. We also investigated various degradation processes that could limit the lifetime of LMGs, which is important for the applicability of such elements. Oxidation of tungsten and silicon as well as changes to the sidewall composition were clearly seen. However, SXR reflectivity remained stable to within measurement accuracy for an extended storage period of 18 months in a 1 atm air environment. The possibility of ...

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Progress in EUV optics lifetime expectations

Cited by 12 publications

References 2 publications

Unraveling the oxidation of Ru using XPS

Unraveling the oxidation of Ru using XPS

Lab- and field-test results of MFIG, the first real-time vacuum-contamination sensor

Single-order lamellar multilayer gratings

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