Metrology capabilities and performance of the new DUV scatterometer of the PTB

Abstract

At PTB a new type of DUV scatterometer has been developed and set up. The concept of the system is very variable, so that many different types of measurements like e. g. goniometric scatterometry, ellipsometric scatterometry, polarisation dependent reflectometry and ellipsometry can be performed. The main applications are CD, pitch and edge profile characterisation of nano-structured surfaces mainly, but not only, on photomasks. Different operation wavelength down to 193nm can be used. The system is not only a versatile tool for a variety of different at-wavelength metrology connected with state-of-the-art photolithography. It allows also to adapt and to vary the measurand and measurement geometry to optimise the sensitivity and the unambiguity for the measurement problem. In this paper the system is presented and described in detail for the first time. Additionally first measurements of grating test structures on a 193nm CoG photomasks are presented. The measurements have to be evaluated by solving the inverse diffraction problem. We finally give a short overview of the evaluation method developed and used by us.

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Comparison of far field characterisation of DOEs with a goniometric DUV-scatterometer and a CCD-based system

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Optical metrology of micro- and nanostructures at PTB: status and future developments

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