| 摘要 |
PURPOSE:To achieve an accurate signal detection of an alignment mark with a low stage difference due to a surface-roughened wafer and a sputter and mark position determination by using any of specific methods and a CCD color area sensor as a sensor when determining a mark position. CONSTITUTION:A first method is used to determine mark parts with photodiodes having each color and photodiode mark positions with a color indicating the maximum contrast of a non-marked part. A second method is used to detect mark positions with photodiodes of each color and then to determine the mark position by averaging the positions. A third method is used to determine mark positions by determining the ratio for determining the mark positions according to the difference in the contrast size between the mark part and non-marked part with the photodiodes of each color. Using either of the above three methods and a CCD color area sensor 27, not only brightness signal but also the spectral wavelength signal of each color are detected to determine mark positions. |
