| 摘要 |
PURPOSE:To perform position detection with 0.01mum order accuracy, and to reduce the size of the device by using a simple optical system and reduce the cost by using the sector Fresnel zone plate as alignment marks. CONSTITUTION:The sector Fresnel zone plate SFZP is used as the alignment marks 16 and 17 of a mask 14 and a wafer 15. Then, each SFZP is so constituted that the main focal planes of Fresnel diffraction images of the mask 14 and wafer 15 are on the same plane when the SFZP is lighted with the laser light of a laser light source 1. Those diffraction images are formed on the same image formation surface through an objective 9 and scanned by a linear sensor 6 at right angles to the lengthwise direction and the obtained electric signal is converted to perform processing. Consequently, the positions of the mask 14 and wafer 15 are detected with 0.01mum order and the optical system is simplified to reduce the cost. |
