Dimensional measurement sensitivity analysis for a MoSi photomask using DUV reflection scatterfield imaging microscopy

Effect of partial coherence on dimensional measurement sensitivity for DUV scatterfield imaging microscopy

“…Exploiting the partial coherence has a different impact when it is applied to the scatterfield imaging microscopy for model-based nanoscale dimensional metrology in which the resolution reaches beyond the diffraction limit and the measurement sensitivity becomes the essential factor [21]. Figure 1 depicts the partial coherence effects on the measurement sensitivity in the scatterfield imaging microscopy by comparing the scattered intensity profile variations at the edges between two kinds of samples, a simple step and multilines with varied linewidths.…”

“…In the experiment, it was noticed that a partially coherent illumination with low numerical aperture (NA) triggered obvious ringing artifacts at the edge of the intensity profiles, which might be related to the measurement sensitivity. To investigate the relationship of the illumination to the sensitivity, a series of measurements for multilines on a Molybdenum Silicide (MoSi) photomask were performed upon various illuminations augmented with incident beam shape, partial coherence factor, and polarization using a 193 nm scatterfield imaging microscope [21]. The results showed that the partial coherence has a significant impact on the improvement of the sensitivity for the dimensional metrology based on the scatterfield imaging microscopy, by altering the scattered field distributions.…”