| 摘要 |
PROBLEM TO BE SOLVED: To provide a system that reduces substrate topography response while generally retaining ability to respond in real time to Z disturbances such as substrate warpage and vibration.SOLUTION: There is provided a system for inspecting a constant layer depth relative to a particular device layer. The system has an image sensor 210 with a fixed focal plane. A focus sensor 208 senses surface topography of a substrate and outputs a focus data stream. A stage moves the substrate in an XY plane, and a motor moves the substrate in a Z dimension. A controller 202 operates the system in one of a setup mode and an inspection mode. The controller 202 feeds the virtual data stream plus an offset to the motor to move the substrate up and down during an inspection, thereby holding the focal plane at a desired Z distance regardless of the surface topography of the substrate.SELECTED DRAWING: Figure 2 |
