| 摘要 |
PROBLEM TO BE SOLVED: To provide a dark field wafer inspection system that reduces influence of the speckle noise.SOLUTION: A dark field inspection system that minimizes the speckle noise due to sample surface roughness can include a plurality of beam shaping paths 101 for generating a composite, focused illumination line on a wafer 104. Each beam shaping path 101 can illuminate the wafer 104 at an oblique angle. The plurality of beam shaping paths 101 can form a ring illumination. This ring illumination can reduce the speckle effect, thereby improving SNR. An objective lens can capture scattered light from the wafer 104 and an imaging sensor can receive output of the objective lens. Because the illumination of the wafer 104 occurs at oblique angles, the objective lens can have a high NA, thereby improving optical resolution of the imaging sensor, and the resulting signal level. |
