| 摘要 |
Disclosed are methods and apparatus for imaging a rounded edge of a sample, such as a wafer with a beveled edge. In one embodiment, the system includes a curved diffuser having an internal surface for positioning towards the rounded edge of the sample and an external surface opposite the internal surface and light sources for generating a plurality of illumination beams adjacent to a plurality of positions on the external surface of the diffuser so that the diffuser outputs uniform light onto the rounded edge of the sample at a wide range of incident angles. The system further includes a sensor for receiving light scattered from the rounded edge of the sample in response to the incident light and generating a detected signal for generating an image. These elements are partially or entirely integrated into a compact assembly. |
