摘要 |
<p>A CSI algorithm for reconstructing grating profiles is disclosed. Solving a volume integral equation for current density, J, employs the implicit construction of vector field, F S related to the electric field, E S , and current density, J, by selection of continuous components of E and J, F being continuous at one or more material boundaries, so as to determine an approximate solution of J. F is represented by at least one finite Fourier series with respect to at least one direction, x, y, and the step of numerically solving the volume integral equation comprises determining a component of J, by convolution of F , with a convolution operator, M comprising material and geometric structure properties in both directions. J may be represented by at least one finite Fourier series with respect to both directions. The continuous components can be extracted using convolution operators, P T and P N , acting on E and J.</p> |