PURPOSE: To enhance the alignment accuracy of the title method by a method wherein a strain amount is detected from a separation distance between marks in a first drawing pattern and a second drawing pattern on a second mask is changed with reference to an optical axis so as to be approximated to the strain amount.
CONSTITUTION: A strain amount in mask detection parts 25, 26 is detected in the following manner: a semiconductor wafer 7 is moved in the X-Y direction; positions of marks 11, 12 which have been formed on the semiconductor wafer 7 in a previous exposure operation are scanned by using the mask detection parts 25, 26 through a projection lens 6; and the positions of the marks 11, 12 are detected. The strain amount is computed by an operation part 24 from the detected positions of the marks 11, 12 and from reference positions of marks 11, 12, 13, 14; the movement amount in the Z-direction of mask-support- stand tilt control devices 4, 5 is computed; a mask support stand 2 is tilted on the basis of the movement amount; the angle of the normal line of a mask 1 to an optical axis is changed by 360°. Thereby, it is possible to enhance the alignment accuracy of the title method.
HIRANUMA MASAYUKI
KIGUCHI YASUO
KUNIYOSHI SHINJI
