| 摘要 |
PURPOSE:To detect an error of positioning with a mask without developing an exposed substrate and facilitate correction for precision positioning immediately before the exposure, by detecting the relative shift of the first pattern on the substrate to be exposed from the second pattern formed as the latent image. CONSTITUTION:After a photoresist layer is formed on a wafer W which has chips, latent images 2a', and 2b which correspond to apertures 2a and 2b of a light shielding part 2 of a reticle R are formed in such a manner that a center distance between the latent image 2a' and an alignment mark 11a formed on the wafer 5 before hand becomes DELTAX' and a center distance between the latent image 2b' and an alignment mark 11b becomes DELTAY'. As the part of the latent image 2a' is saturated with absorbed exposure energy, it has higher reflectance than the unexposed part. Then a computing control means 15 calculates the actual distance DELTAX' between the latent image 2a' and the alignment mark 11a in accordance with a photoelectric signal Is and a position signal Xs and further calculation DELTAX'-alphaX and calculates discrepancy deltaX' to the X-direction when the reticle R and the wafer W are overlapped. |
