Abstract-High resolution radar imaging techniques can be used in ballistic missile defence systems to determine the type of ballistic missile during the boost phase (threat typing) and to discriminate different parts of a ballistic missile after the boost phase. The applied radar imaging technique is 2D Inverse Synthetic Aperture Radar (2D-ISAR) in which the Doppler shifts of various parts of the ballistic missile are employed to obtain a high cross-range resolution while the resolution in downrange is achieved with a large radar bandwidth. For a 10 cm downrange resolution, a radar bandwidth of more than 1.5 GHz is required. However, this requirement is not compatible with EM frequency spectrum allocations for long range ballistic missile defence radars that operate in the L, S, and C frequency band. In this paper, a novel coherent multiband ISAR imaging technique is proposed that employs two or more narrowband radar systems that operate in different frequency bands. The coherent multiband imaging process uses an advanced interpolation technique to achieve a very high downrange resolution and produces little artifacts due to noise.

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TNO has built EBL2, an EUV exposure facility equipped with an in vacuo X-ray photoelectron spectroscopy setup (XPS) and an in-situ ellipsometer. EBL2 enables lifetime testing of EUV optics, photomasks, pellicles and related components under development in relevant EUV scanner and source conditions, which was previously not available to industry. This lifetime testing can help the industry to prepare for high volume production using EUV lithography by bringing forward information about material behavior which facilitates the development cycle. This paper describes an EUV photomask lifetime test performed at EBL2. The mask was exposed to different EUV doses under a controlled gas and temperature environment. To investigate how EUV light interacts with the mask, various analysis techniques were applied before and after EUV exposure. In-situ XPS was used to investigate elemental compositions of the mask surface. An ex-situ critical dimension scanning electron microscope (CD-SEM) and an atomic force microscope (AFM) were used to explore the impact of EUV light on critical dimensions (CD) and feature profiles. In addition, EUV reflectometry (EUVR) was used to investigate the change of reflectivity after EUV exposures. The exposure conditions are reported, as well as an analysis of the effects observed.