| 摘要 |
PROBLEM TO BE SOLVED: To transfer an excellent pattern within the focal depth of a projection lens, by exposing a transferring mask having a diffraction type lens to a light. SOLUTION: When an illumination light 400 of an illumination optical system 4 enters mask 5, an aperture pattern 51 is drawn in a position corresponding to a cell part 31, and a diffraction type lens pattern 52 is drawn in a position corresponding to a peripheral circuit part 32 in a mask 5. A light 410 outputted from the aperture pattern 51 forms its image in a contact hole 310 on the cell 31 via projection lenses 2. A light 420 outputted from the diffraction type lens 52 once forms an image at an imagery point A below the mask 5, and the imagery point A is formed in a contact hole 320 on the peripheral circuit 32. The distance (f) between the imagery point A and the mask 5 is determined in accordance with the step-difference Z between the cell 31 and the peripheral circuit 32. Letting the projection magnification of the projection lenses 2 be M, the relation between (f) and Z is given by f=Z/M. The focal length of the diffraction type lens 52 is so designed that it becomes equal to the distance (f). |
