Importance

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Abstract

An apparatus for measuring an alignment accuracy between overlaid alignment marks formed to each of alignment mark portions on every plural chip units or exposure units arranged on a substrate to be measured, comprising: an XY stage running in a direction x and in a direction y while mounting the substrate; an illumination optical system for illuminating each of the alignment mark portions in a state where the XY stage runs in a direction x which is a direction of arranging the chips; a detecting optical system having an objective lens for collecting a reflection light in the running state obtained from the overlaid alignment marks, a focusing optical system for focusing the reflection light in the running state obtained from the objective lens, a scanning optical system for scanning reflection light image in the running state focused by the focusing optical system in a direction opposite to that of the running and a linear image sensor receiving reflection light image substantially in a static state being scanned in the opposite direction by the scanning optical system and converting them into image signal; and an alignment accuracy calculation device for measuring the alignment accuracy between the overlaid alignment marks at least for a direction perpendicular to the running direction based on the image signal converted by the linear image sensor.

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First Claim