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Spectroscopic ellipsometry is a very sensitive optical metrology technique commonly used in semiconductor manufacturing lines to accurately measure the thickness and refractive index of different layers present on specific dedicated metrology targets on the wafers. In parallel, optical defectivity techniques are widely implemented in production lines to inspect a significant amount of dies representative of the full wafer and detect physical and patterning defects. A new approach can then simply emerge which is to apply ellipsometry metrology techniques at a full or die wafer scale. This strategy, at the frontier between metrology and defectivity field is expected to bring solutions for certain types of process deviation. In our case, ellipsometry’s optical response was collected on large areas of product wafers to capture specific deviations such as film properties, thickness, and patterning variation. This is an innovative strategy that relies on a model-less approach to detect process drifts, using ellipsometry’s sensitivity to material properties and design architecture variations. In this paper, we will present this approach on three industrial cases. [ABSTRACT FROM AUTHOR]

Abstract: Fabrication of devices at the 45nm node and beyond requires resist film with a thickness below 150nm. The physicochemical properties of thin films, such as glass transition, are in general different from the bulk ones and new characterization tools are often necessary. The glass transition of thin resist films has been studied by two techniques: spectroscopic ellipsometry and multi wavelength optical interferometry. Films of simple homopolymers (PS, PMMA) and a EUV polymer platform supplied by AZ Electronic Materials were studied and their values were compared with DSC measurements of the bulk material. A variation of the glass transition temperature was detected with both techniques for PS and PMMA when the thickness of the film decreases below 100nm. Indications for additional interesting interactions for moderately thick films (100–300nm) especially in the case of PMMA are reported. [Copyright &y& Elsevier]