| 摘要 |
An alignment system usable in a semiconductor device manufacturing apparatus of step-and-repeat type for superposingly printing a pattern of a reticle onto each of patterns on a semiconductor wafer in a step-and-repeat manner. The alignment system is adapted to align each of the patterns of the wafer with respect to the pattern of the reticle, prior to exposure for printing the pattern, by use of alignment marks provided for each pattern of the wafer. In this alignment system, if the alignment marks for a particular pattern on the wafer are damaged or wiped off by the chemical or thermal treatment of the wafer, the alignment of the particular pattern of the wafer with respect to the pattern of the reticle is achieved on the basis of positional information detected from another alignment mark provided for another pattern of the wafer adjacent to or in the neighborhood of the particular pattern of the wafer, whereby the pattern of the reticle can be accurately overlaid on the particular pattern of the wafer.
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