Preparation and characterization of gold nanocrystals on NaCl(100) surfaces as labels for the dynamical x-ray tracking technique

Slieh J, Winter A, Gryzia A, et al. Preparation and characterization of gold nanocrystals on NaCl(100) surfaces as labels for the dynamical x-ray tracking technique. Thin Solid Films. 2009;517(11):3257-3261.We report on the fabrication of single crystalline gold nanocrystals of sizes between 10 nm and 25 nm. Gold was deposited under ultra high vacuum conditions on a freshly-cleaved NaCl(100) surface by means of the Molecular Beam Epitaxy technique. The preparation parameters substrate temperature and average thickness of the deposited gold were studied systematically. After the preparation, the crystals were characterized by means of different techniques, such as Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), X-Ray Diffractometry (XRD) and Laue Diffractometry. Measurements of the deposited cluster size, as measured by AFM, and the crystal size, as measured by XRD exhibited similar results at substrate temperatures between approx. 200 degrees C and 250 degrees C, indicating a high amount of single gold crystals. TEM images of gold crystals, made after the gold crystals had been dissolved in an aqueous 3-[(3-cholamidopropyl)dimethyl-ammonio]propane solution, support these results. Further, an effect of the substrate temperature during the deposition on the orientation of the gold crystals with respect to the NaCl(100) surface was observed. XRD measurements reveal a perpendicular texture of Au (111) parallel to NaCl(001) at approximately 310 degrees C. The second detected texture:Au(001)parallel to NaCl(001) (in plane) and Au[100]parallel to NaCl[100] (perpendicular) was observed over the complete studied temperature range (180 degrees C-330 degrees C). (C) 2008 Elsevier B.V. All rights reserved

Actinic inspection of EUVL mask blank defects by photoemission electron microscopy: Effect of inspection wavelength variation

Lin J, Neuhaeusler U, Slieh J, et al. Actinic inspection of EUVL mask blank defects by photoemission electron microscopy: Effect of inspection wavelength variation. In: Microelectronic Engineering. MICROELECTRONIC ENGINEERING. Vol 84. ELSEVIER SCIENCE BV; 2007: 1011-1014.Extreme ultraviolet (EUV) photoemission electron microscopy (PEEM), which employs standing wave field illumination of a sample, is a potential tool for at-wavelength inspection of phase defects on extreme ultraviolet lithography (EUVL) mask blank. In this paper, we will demonstrate that the contrast of an underneath multilayer programmed defect in EUV-PEEM image is strongly dependent on the inspection wavelength. The observed contrast variation at different inspection wavelengths is in good agreement with the simulation result of a standing wave field on surface of multilayer stack in the mask blank sample. We also observed some native defects on the programmed defect sample, and found that some of them reverse their contrast with varying inspection wavelengths while others do not. (c) 2007 Elsevier B.V. All rights reserved

High-resolution actinic defect inspection for extreme ultraviolet lithography multilayer mask blanks by photoemission electron microscopy

Neuhäusler U, Oelsner A, Slieh J, et al. High-resolution actinic defect inspection for extreme ultraviolet lithography multilayer mask blanks by photoemission electron microscopy. APPLIED PHYSICS LETTERS. 2006;88(5): 053113.We report on the development and first experimental results of a "at wavelength" full-field imaging technique for defect inspection of multilayer mask blanks for extreme ultraviolet (EUV) lithography. According to the International Semiconductor Roadmap by Sematech, less than 5x10(-3) defects per cm(2) should be present on such multilayer mask blank to enable mass production of microelectronics using EUV lithography, thus fast high-resolution methods for mask defect inspection and localization are needed. Our approach uses a photoemission electron microscope in a normal incidence illumination mode at 13 nm to image the photoelectron emission induced by the EUV wave field on the multilayer mask blank surface. We show that by these means, buried defects in the multilayer stack can be probed down to a lateral size of 50 nm. (c) 2006 American Institute of Physics

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

Neuhäusler U, Lin J, Oelsner A, et al. A new approach for actinic defect inspection of EUVL multilayer mask blanks: Standing wave photoemission electron microscopy. In: Microelectronic Engineering. MICROELECTRONIC ENGINEERING. Vol 83. ELSEVIER SCIENCE BV; 2006: 680-683.Extreme ultraviolet lithography (EUVL) at 13.5 nm is the next generation lithography technique capable of printing sub-50 nm structures. With decreasing feature sizes to be printed, the requirements for the lithography mask also become more stringent in terms of defect sizes and densities that are still acceptable and the development of lithography optics has to go along with the development of new mask defect inspection techniques that are fast and offer high resolution (preferable in the range of the minimum feature size) at the same time. We report on the development and experimental results of a new 'at wavelength' full-field imaging technique for defect inspection of multilayer mask blanks for EUV lithography. Our approach uses a photoemission electron microscope (PEEM) in a normal incidence illumination mode at 13 nm to image the photoelectron emission induced by the EUV wave field on the multilayer mask blank surface. We show that by these means, buried defects in the multilayer stack can be probed down to a lateral size of 50 nm, which was the smallest pre-defined structure size under study so far. The PEEMs spatial resolution has been proven to be as small as 29 nm edge slope width in measurements with 250 nm radiation. Therefore, the capability of this technique for actinic measurements at 13 nm radiation is anticipated to be well below 50 nm. (c) 2006 Elsevier B.V. All rights reserved