| 摘要 |
PURPOSE:To execute an alignment with stable and high accuracy by deriving the center position of an alignment pattern from the shape variation position of an interference pattern, and eliminating the drop of the alignment accuracy caused by the applied film thickness and the uneven application of a photoresist. CONSTITUTION:An illuminating light beam 41 from a coherence light source 40 is separated into two directions by a beam splitter 42, and one of them becomes an illuminating light beam 43 and radiates an alignment pattern 48 through a reduced projection lens 2, and the other is made incident on a semitransparent mirror 51. Subsequently, in accordance with a relative inclination in the optical axis direction of a wave front of reflected light 52 from the mirror 51, and the wave front of the reflected light from an interface 47 of a step difference pattern of Si 45 and a photoresist 46, a fringe pattern is generated. The fringe pattern is generated due to the influence of an interference of the reflected light 50 and 52,and a large signal variation caused by a fact that the phase is varied by step difference depth (e) in the step difference part of the pattern 48 is obtained. Accordingly, the influence of an interference caused by film thickness d(x) of the photoresist 46 is reduced relatively, and the alignment can be executed with stable and high accuracy. |
