| 摘要 |
PURPOSE:To enable alignment even when a wafer is exposed by X-rays by reflecting a mask and an alignment mark on the wafer faced onto the four corners of an exposure pattern and positioned at a fine interval to a chromatic aberration objective while sensing the positions of the mask and the alignment mark on the wafer. CONSTITUTION:A chromatic aberration objective 1 and a thin-film mirror 2 are combined and used in a detection optical system, and the thin-film mirror 2 has excellent transmittance to X-rays and extremely low transmittance to visible light. The thin-film mirror 2 is arranged at an angle of 45 deg.-800 deg. on the upper sides of one corner or more of the four corners of a mask 3, and an alignment mark 4 on the mask 3 is reflected and the chromatic aberration objective 1 is positioned in the direction of the reflection of the alignment mark 4 and the alignment mark 4 is detected by visible light. The images of the mask and the alignment mark on a wafer optically enlarged by the chromatic aberration objective 1 are digital-quantitized as the video signal of an electric signal, and signal-processed, thus sensing each position. Accordingly, the mask and the wafer can be aligned accurately even during X-ray exposure. |
