摘要 |
Disclosed herein is an apparatus and method which is capable of accurately measuring surface status, such as a minute variation in height (the height difference), a protrusion, a depression, surface damage and/or surface roughness, at each point on the surface of the object to be measured in an optical manner. In particular, the present invention provides an optical surface measuring apparatus and method which is capable of accurately measuring the minute surface status of the object to be measured using both a signal from an interferometer and a Focus Error (FE) signal from a Position Sensitive Detector (PSD) in order to overcome the 2π-ambiguity of the conventional interferometers and the limitation of the Focus Error (FE) signal.
|