A new approach for actinic defect inspection of EUVL multilayer mask blanks: Standing wave photoemission electron microscopy

Neuhäusler, U.; Lin, Jingquan; Oelsner, A.; Schicketanz, M.; Valdaitsev, D. A.; Slieh, J.; Weber, Nils; Brzeska, Monika; Wonisch, Andreas; Westerwalbesloh, T.; Brechling, Armin; Brückl, Hubert; Escher, M.; Merkel, M.; Schönhense, G.; Kleineberg, Ulf; Heinzmann, Ulrich

doi:10.1016/j.mee.2005.12.035

Cited by 6 publications

(2 citation statements)

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“…The spatial resolution of this instrument has been measured to be 29 nm ͑edge slope width, following a 16%-84% criterion͒ using a 248 nm wavelength Hg discharge lamp source in the normal incidence illumination configuration. 8 During our initial experiments with this near normal incidence illumination EUV-PEEM, a flat multilayer mirror was used as a microreflector to couple EUV light to illuminate the mask blank sample, and several minutes of acquisition time were required to obtain a clear EUV-PEEM image with a field of view of about 100 m. 9 This unsatisfactory long acquisition time is required due to the EUV focal size of diameter of about 1 mm on the mask blank sample, which is much larger than the field of view of the PEEM ͑a typical value of about 100 m͒ at high magnification mode. In order to increase the photon flux density on the sample, improvement was made to replace the flat multilayer mirror by a toroidal multilayer mirror ͑see photo in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…As a result, with the same magnitude of incident photon flux, the EUV-PEEM image acquisition time was reduced down to subsecond. 9 The mask blank inspection experiments were carried out at two different undulator beamlines ͑linear undulator U125͒ at the 1.7 GeV electron storage ring BESSY II in Berlin, Germany. The beamline "U125-1/PGM" is equipped with a grazing incidence plane grating monochromator, while the beamline U125-1/ML utilizes a near normal incidence multilayer monochromator.…”

Section: Methodsmentioning

confidence: 99%

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Actinic extreme ultraviolet lithography mask blank defect inspection by photoemission electron microscopy

Lin

Neuhaeusler

Slieh

et al. 2006

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

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A new method for the actinic inspection of defects inside and on top of extreme ultraviolet (EUV) lithography multilayer-coated mask blanks is presented. The experimental technique is based on photoemission electron microscopy supported by the generation of a standing wave field inside and above the multilayer mask blank when illuminated near the resonance Bragg wavelength at around 13.5nm. Experimental results on programed defect samples based on electron beam lithographic structures or silica balls overcoated with an EUV multilayer show that buried defects with a lateral size down to 50nm are detectable. Furthermore, phase structures as shallow as 6nm in height on a programed phase grating sample have been detected by this technique. The contrast of the phase defect structures has shown to be strongly dependent on and controlled by the phase of the standing wave field at the mask blank surface, and thus can be optimized by tuning the inspection wavelength.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%