| 摘要 |
PURPOSE:To make the line width control precise, and improve its reproducivility, by performing the calibration of focus fluctuation in consideration of the curvature of field of a projection optical system due to various factors, and always performing an adequate focusing on the whole part of an exposure surface. CONSTITUTION:Various factors of fluctuation of the curvature of field are measured, and the curvature of field is persued by an operation based on the previously stored relation between these factors and the carvature of field. Therefor, a focus position is calibrated at the averaged focus position of an exposure surface. When a part of the exposure surface is only used, the focus position is calibrated at the averaged focus position of said part. As the shift of focus due to the carvature of field becomes the shift from the averaged focus position, it becomes smaller as compared with the shift from the center position of the exposure surface. Therefor, the possibility wherein defective devices due to the curvature of field in prior arts can become non-defective devices is increased. |
