| 摘要 |
PURPOSE:To prevent an optical performance from dropping due to movement of a focus generated by a temperature variation, by correcting a focal position basing on a focal position read out of a storage means in accordance with a detected temperature in a projecting optical system. CONSTITUTION:A focus moving extent corresponding to a temperature variation of a projecting optical system 4 measured and determined in advance through an input device 12 is inputted in advance to a storage device 11. When a pattern of a mask 3 is projected onto a wafer 6 and printed, a temperature distribution or an average temperature which has detected a temperature of the projection lens 4 by a temperature detector 5 is inputted to a controlling circuit 10. The controlling circuit 10 reads out a focus moving extent of a device in this detected temperature from the storage device 11, and a voltage corresponding to this focus moving extent is applied to a voltage element 9. The piezoelectric element 9 expands and contracts in accordance with the applied voltage, moves a wafer chuck 7 in the upper and lower directions, and the wafer 3 is maintained at the best image forming position. In this way, lowering of an optical performance by a temperature variation is prevented. |
