Sensitivity analysis for indirect measurement and profile reconstruction in scatterometry

To control the design and manufacturing of lithographic masks a fast and non-destructive measurement technique is needed. In scatterometry the mask is illuminated by plane waves from various directions, the scattered light is measured, and the geometry of the mask surface is reconstructed from the measured data. The quality of reconstruction surely depends on the angles of incidence, on the wave lengths and/or the number of propagating scattered wave modes. Optimizing the conditioning of some Jacobian matrices, we develop a sensitivity analysis to find an optimal measurement configuration for scatterometry. Our first important test geometry is a simple periodic line-space structure. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)