Using imaging ellipsometry to determine angular distribution of ellipsometric parameters without scanning mechanism

• A focused beam imaging ellipsometric system was developed in this work.
• Incident rays of a focused beam on the ideal incident plane can be analyzed.
• Ellipsometric parameters varied with incidences can be obtained without scanning.
• Measurements of two different film thicknesses zones were demonstrated.

This work presents a focused beam approach using a polarizer-sample-analyzer (PSA) imaging ellipsometer to deduce multiple sets of ellipsometric parameters with the information of multiple incident angles in one measurement. Using a three-intensity measurement technique, an additional parameter α can be obtained to locate the ideal incident plane of a focused beam. Meanwhile, the ellipsometric parameters on the ideal incident plane are also analyzed. Based on α and the ellipsometric parameters, the variation in the intensity and phase response with a range of incident angles are examined without using a mechanical scanning apparatus. Measurements made of two zones on a reference wafer with different film thicknesses demonstrate results that are almost consistent with those predicted by the theoretical model.