METHOD FOR MEASURING PATTERN MISALIGNMENT

摘要

According to one embodiment, a method for measuring pattern misalignment, includes: a first step obtaining image data; a second step specifying a measurement region; a third step calculating a first shift amount (x1, y1); a fourth step determining, after calculating the first shift amount, a first distribution; a fifth step executing a plurality of times the second step, the third step, and the fourth step; a seventh step calculating a second shift amount (x2, y2); an eighth step determining, after calculating the second shift amount, a second distribution; a ninth step executing a plurality of times the sixth step, the seventh step, and the eighth step; and a tenth step calculating a difference (x2−x1, y2−y1) between the second pattern misalignment and the first pattern misalignment.

主权项

1. A method for measuring pattern misalignment, comprising:
a first step obtaining image data of a surface image of a to-be-measured substrate including on its surface a first layer having a first pattern and a second layer provided on the first layer and having a second pattern from the surface side of the substrate, the surface image including an image of the first pattern and an image of the second pattern, and the image data being represented by an X-Y coordinate system; a second step specifying a measurement region in the image data and to specify a first reference region corresponding to the measurement region in design data of the first pattern represented by the X-Y coordinate system; a third step calculating a first shift amount (x1, y1) of the first reference region in the X-Y coordinate system using a pattern matching technique when a portion of the design data of the first pattern in the first reference region is best matched with a portion of the image data corresponding to the image of the first pattern in the measurement region; a fourth step determining, after calculating the first shift amount, a first distribution of spacing between a first contour and a first design contour and to calculate a first standard deviation of the first distribution, the first contour defining the portion of the image data corresponding to the image of the first pattern in the measurement region, and the first design contour defining the portion of the design data of the first pattern in the first reference region; a fifth step executing a plurality of times the second step, the third step, and the fourth step while expanding the measurement region of the second step, and then when it is determined that the first standard deviation for last execution is stabilized, to take the first shift amount (x1, y1) for the last execution as a first pattern misalignment; a sixth step specifying a measurement region in the image data and to specify a second reference region corresponding to the measurement region in design data of the second pattern represented by the X-Y coordinate system; a seventh step calculating a second shift amount (x2, y2) of the second reference region in the X-Y coordinate system using a pattern matching technique when a portion of the design data of the second pattern in the second reference region is best matched with a portion of the image data corresponding to the image of the second pattern in the measurement region; an eighth step determining, after calculating the second shift amount, a second distribution of spacing between a second contour and a second design contour and to calculate a second standard deviation of the second distribution, the second contour defining the portion of the image data corresponding to the image of the second pattern in the measurement region, and the second design contour defining the portion of the design data of the second pattern in the second reference region; a ninth step executing a plurality of times the sixth step, the seventh step, and the eighth step while expanding the measurement region of the sixth step, and then when it is determined that a value of the second standard deviation for last execution is stabilized, to take the second shift amount for the last execution as a second pattern misalignment (x2, y2); and a tenth step calculating a difference (x2−x1, y2−y1) between the second pattern misalignment and the first pattern misalignment as a misalignment of the second pattern with respect to the first pattern.