| 摘要 |
PURPOSE:To align a position with high reliability without being affected by disturbance such as lighting uneveness by a method wherein an image which is obtained by applyig the light to a semiconductor wafer and a mask which overlap each other is converted into image signal to each axial direction by a solid state image pickup tube and is processed. CONSTITUTION:The light irradiated from a source 17 is converted into the parallel beam by a condensor lens 16 and is reflected by a semitransparent mirror 15 and is applied to the target pattern 3 and 5 through an object lens 14. The light reflected by the target pattern 3 and 5 passes through the object lens 14 and the semitransparent mirror 15. The image of the light which is reflected by a semitransparent mirror 18 and that of the light which passes through the mirror 18 are compressed to X- and Y-axis direction by cylindrical lenses 20 and 21 respectively and are focused on photodiode alleys 22 and 23. The position of the target pattern can be positioned by processing these outputs to produce signals. |
