Metrology of laser-produced plasma light source for EUV lithography

Boewering, Norbert R.; Hoffman, J.; Khodykin, O. V.; Rettig, C. L.; Hansson, Björn; Ershov, Alexander I.; Fomenkov, Igor V.

doi:10.1117/12.600809

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…A detailed description of the diagnostics used in this paper is given in [2]. Therefore, we will only present a brief description of each diagnostic below, followed by a summary of the results obtained.…”

Section: Methodsmentioning

confidence: 98%

“…The EUV pinhole camera [2] is used for EUV imaging of the LPP source. The EUV pinhole camera consists of a 50 mm pinhole, a 0.2 mm Zr filter (placed right after the pinhole), a calibrated 45° Si/Mo MLM, and a 512x512 CCD camera.…”

Section: Methodsmentioning

confidence: 99%

“…A high-resolution flat field spectrometer [2] was built to look at EUV plasma emission spectra produced in various laser/target combinations. The advantage of this type of spectrometer over scanning grazing incidence spectrometers is that the entire spectrum range is recorded in a single shot.…”

Section: High Resolution Spectrum Measuremetnsmentioning

confidence: 99%

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LPP EUV conversion efficiency optimization

Hoffman¹,

Bykanov²,

Khodykin³

et al. 2005

SPIE Proceedings

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Efficient conversion of laser light into EUV radiation is one of the most important problems of the laser-produced plasma (LPP) EUV source. Too low a conversion efficiency (CE) increases the amount of power the drive laser will have to deliver, which, besides the obvious laser cost increase, also increases the thermal load on all the components and can lead to increased debris generation. In order to meet the requirements for a high-volume manufacturing (HVM) tool and at the same time keep the laser power requirements within acceptable limits, a CE exceeding 2.5% is likely to be required. We present our results on optimizing conversion efficiency of LPP EUV generation. The optimization parameters include laser wavelength, target material, and laser pulse shape, energy and intensity. The final choice between parameter sets that leads to the required minimum CE is dependent on the debris mitigation solutions and the laser source available for a particular parameter set.

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Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

LPP EUV conversion efficiency optimization

Hoffman¹,

Bykanov²,

Khodykin³

et al. 2005

SPIE Proceedings

Self Cite

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“…Besides absorptive filters that block wider spectral ranges, XUV monitoring and metrology is making use mainly of periodic multilayer mirrors for selective reflection [5][6][7][8][9][10][11] of a desired, narrowband wavelength interval. However, with periodic layers, the shape of the spectral transmission peak is fixed due to the periodicity of the layer stack.…”

Section: Introductionmentioning

confidence: 99%

Reflective aperiodic multilayer filters for metrology at XUV sources

et al. 2020

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We present a general method for designing XUV aperiodic multilayer mirrors that can mimic a given target spectrum, specifically, the spectral transmission of an XUV optical system. The method is based on minimizing a merit function and using fidelity parameters that quantify the matching of the multilayer reflectivity spectrum with that of the target spectrum. To assess the feasibility of fabricating such a system, we show how to reduce the layer-to-layer thickness variations throughout the aperiodic layer stack. We demonstrate the design method using an example of an EUV optical system composed of 12 identical Mo/Si multilayer mirrors having a reflectivity peak at 13.5 nm. We found that the target spectrum can be mimicked with high fidelity either with a single reflection at an aperiodic multilayer mirror combined with standard absorbing filters or, if required, with two subsequent reflections at a mimic mirror. These examples demonstrate the applicability for metrology at XUV sources, including spectrally proper source imaging. Because our approach is of general applicability, the process can be used to mimic any other narrowband, single-peaked target spectrum in the XUV region.

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“…They are already used to serve as X-ray optical elements in microscopes 1 , telescopes, 2 spectroscopes, 3 plasma physics, 4 etc. The maximal theoretical reflectivity achieves ~76% at normal incidence.…”

Section: Introductionmentioning

confidence: 99%

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

et al. 2011

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Impact of Ar gas pressure (1−4 mTorr) on the growth of amorphous interlayers in Mo/Si multilayers deposited by magnetron sputtering was investigated by small-angle x-ray scattering (λ=0.154 nm) and methods of cross-sectional transmission electron microscopy. Some reduction of thickness of the amorphous inter-layers with Ar pressure increase was found, while composition of the layers was enriched with molybdenum. The interface modification resulted in raise of EUV reflectance of the Mo/Si multilayers.

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Metrology of laser-produced plasma light source for EUV lithography

Cited by 6 publications

References 4 publications

LPP EUV conversion efficiency optimization

LPP EUV conversion efficiency optimization

Reflective aperiodic multilayer filters for metrology at XUV sources

The influence of working gas pressure on interlayer mixing in magnetron-deposited Mo/Si multilayers

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