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Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology. Both experimental and modelling methods will be enhanced and different methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurement systems in measurement comparisons. Additionally novel methods for sophisticated data analysis will be developed and investigated to reach significant reductions of the measurement uncertainties in critical dimension (CD) metrology. One final goal will be the realisation of a wafer based reference standard material for calibration of scatterometers. [ABSTRACT FROM AUTHOR]

The technological limits to the beam quality of modern synchrotron-radiation sources are set by the geometrical accuracy of the optical components. The fabrication of these components is limited by the measuring technique. The exactly measured topography of the surface under test (SUT) allows postprocessing (e.g. ion beam etching). For form components of the SUT this is possible between its whole length and some millimeters. Present measurement technologies such as long-trace profilers, reach slope uncertainties down to 50 milli-arcsec rms. Their height uncertainty corresponds to several tens of nanometers for a synchrotron mirror 1 m in length. The parabolic and long-wave contributions of form in particular might differ due to systematic errors of the slope measurement. In the context of a cooperative research project initiated by BESSY, two profilers have been set up at the PTB — one for the absolute definition of flatness, the second presented here is faster and more robust. They operate with commercial autocollimators implementing the ESAD method. Only angle differences are used to reconstruct the topography of the SUT. This completely rejects common errors of angle measurement as guide errors and whole body movements of the SUT. This deflectometric method works without a lateral straightness reference and is capable of measuring free-form surfaces. We show results with a slope reproducibility of up to some milli-arcsec and a length of up to 88 cm. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]