Overlay measurement method of overlay mark

Abstract

An overlay measurement method for overlay marks. The overlay measurement method includes the following steps: Providing an overlay mark. Performing multiple region selection processes on the overlay mark using an overlay measurement device. The region selection process includes defining a region corresponding to a pattern as a first region and defining a region corresponding to the area between adjacent patterns as a second region. After each region selection process, performing an offset value calculation process using the overlay measurement device to obtain an initial offset value. After performing multiple region selection processes, multiple initial offset values ​​are obtained, including multiple good values ​​and multiple bad values. Excluding the multiple bad values, and obtaining a final offset value based on the multiple good values.

Claims

1. A method for measuring the overlap of overlapping marks, comprising: An overlay mark is provided, wherein the overlay mark includes a plurality of first patterns and a plurality of second patterns arranged in parallel in a first direction, each of the first patterns and each of the second patterns being strip-shaped and extending in a second direction orthogonal to the first direction, and the plurality of first patterns and the plurality of second patterns being arranged in the second direction; Using an overlay measurement device, multiple region selection processes are performed on the overlay mark. Each region selection process includes: defining a region corresponding to a pattern as a first region; and defining a region between adjacent patterns as a second region. After each region selection process, an offset value calculation process is performed. This offset value calculation process includes: using the overlay measurement device, performing image processing corresponding to the result of the region selection process to obtain a first grayscale signal of the plurality of first patterns and a second grayscale signal of the plurality of second patterns in the first direction; and using the overlay measurement device, calculating an initial offset value based on the first grayscale signal and the second grayscale signal. After multiple region selection processes, multiple initial offset values ​​are obtained, including multiple good values ​​and multiple bad values. The good values ​​correspond to the case where neither the first region nor the second region contains the edge portion of the pattern, and the bad values ​​include all values ​​other than the good values. The multiple bad values ​​are excluded, and a final offset value is obtained based on the multiple good values.

2. The method for measuring the overlap of overlapping marks as described in claim 1, wherein the defective value corresponds to the case where the first region does not contain the edge portion of the pattern, while the second region does contain the edge portion of the pattern.

3. The method for measuring the overlap of overlapping marks as described in claim 1, wherein the defective value corresponds to the case where the first region contains the edge portion of the pattern and the second region does not contain the edge portion of the pattern.

4. The method for measuring the overlap of overlapping marks as described in claim 1, wherein the defective value corresponds to the case where both the first region and the second region contain the edge portion of the pattern.

5. The method for measuring the overlap of overlapping marks as described in claim 1, wherein the final offset value is the average of the plurality of good values.

6. The method for measuring the overlap of overlapping marks as described in claim 1, wherein the region selection process is performed at least 7 times for the overlapping mark.

7. The method for measuring the overlay of overlay markers as described in claim 1, wherein the overlay markers include advanced image metrology markers.

8. The method for measuring the superposition of superposition marks as described in claim 7, wherein the superposition measuring device includes an image measurement system.

9. The method for measuring the overlap of overlap marks as described in claim 1, wherein the overlap marks are disposed in the dicing region of a semiconductor substrate.

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