Importance

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Abstract

The method of the present invention is used to measure overlay accuracy between a first pattern including a plurality of marks formed on a substrate and a second pattern including a plurality of marks formed on the first pattern. First overlay accuracy is measured by using an erected image of a combination of marks of first and second patterns corresponding to each other. Second overlay accuracy is measured by using an inverted image of the combination of marks. Third overlay accuracy is measured by using an erected image or an inverted image of the combination of marks. Differences between the first overlay accuracy measured by using the erected image and the second overlay accuracy measured by using the inverted image are respectively obtained with respect to some combinations of marks of first and second patterns. An average of the differences is calculated. All measured values of the first overlay accuracy and the third overlay accuracy or the second overlay accuracy and the third overlay accuracy are corrected based on the average. Thus, it is possible to correct measured values of overlay accuracy at a short time.

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First Claim