| 摘要 |
PURPOSE:To perform an accurate positioning operation even when the distance between a laser mirror for length-measuring use and an object to be treated is changed and to make the members for the title device small-sized and lightweight. CONSTITUTION:A top table 4 provided with a holding stand 3 which vacuum- sucks and fixes a laser mirror 1 for length-measuring use and an object 2 to be treated (hereinafter called a wafer) is provided with a holding-stand rotation mechanism 5 which is required to align the wafer 2. As a result, a distance is formed between the laser mirror 1 for length-measuring use and the holding stand 3. An electric micrometer 6 or an electrostatic capacity sensor is installed at the holding stand 3; the distance between it and the laser mirror 1 for length- measuring use is measured; a correction amount is added to a laser target value for a positioning position, fed back and controlled. |
