| 摘要 |
PROBLEM TO BE SOLVED: To provide a system and a method for determining the height of a surface of a specimen such as a height of a semiconductor device wafer. SOLUTION: The system generates a comparison signal that can be used to change the fine height adjustment of the Z axis of the system. The system, for example, includes a treatment tool that can be used in the manufacture of a semiconductor device a measuring tool, or an inspection tool. In this manner, the system maintains a fixed working interval between a wafer surface and the optical column of the system. The system includes an off-axis dual beam symmetric height sensor by the mechanical restriction of the system. The dual beam symmetric height sensor can accurately achieve an automatic focus adjustment of a wafer by essentially eliminating the wafer pattern induced error of the comparison signal that is generated by the system. COPYRIGHT: (C)2004,JPO |
