| 摘要 |
PURPOSE:To make an alignment more accurately by a method wherein the actual locations of a plurality of cell patterns picked up from all the cell patterns formed on a die are detected and how much the actual locations deviate from the designed ones is calculated for each cell pattern and the calculated values are averaged and then the average value is used as the amount of correction when a wafer stage is moved for an alignment. CONSTITUTION:Some cell patterns are picked up from all the cell patterns 7. For example, four cell patterns 7A-7D are picked up in this case. The actual locations (XZ,YA)-(YD,YD) of the four cell patterns 7A-7D on a die 2 are detected by picture processing or other method. Then, how much the actual locations (XA,YA)-(XD,YD) of the cell patterns 7A-7D on the die 2 deviate from the designed locations is calculated for each cell pattern. The values gained from the calculations are averaged. Using the average value as the amount of correction, a wafer stage is moved. The location of the die 2 is corrected by the average value of the deviation amounts of a plurality of the cell patterns 7A-7D formed on the die 2. Consequently, an overlay accuracy between the already formed pattern 7 and a pattern to be formed in the next process can be increased. |
