| 摘要 |
PURPOSE:To improve the precision of alignment by adding the alighnment in the rotating direction to chip alignment. CONSTITUTION:Two targets P and Q are set apart at a distance A from each other within a block 3 of one chips. After alignment in the directions of X and Y is performed, the displacement of X1, Y1, X2 and Y2 of the targets P and Q on a wafer from targets P and Q on a mask is measured through a projection optics system. An error theta in the direction of rotation can be determined from this displacement. Next, the error theta is compensated by rotating the wafer, and the displacement of DELTAX and DELTAY of the center of the chip from the center of the mask brought about thereby is compensated. A mark O denotes the center of rotation of the wafer, x and y the coordinates of the center of the chip before the compensation by rotation, and x' and y' the coordinates of the center of the chip (on the wafer) after said compensation. By repeating further the alignment in the directions of X and Y after the compensation by rotation is ended, the precision of the alignment can be improved. |
