Abstract: There is provided a deep learning-based overlay key centering system and a method thereof that may precisely measure and examine an alignment state of fine patterns of a semiconductor substrate. The method includes collecting an input data set from at least one device, the input data set comprising measurement image data of an overlay key and label data including information on a position and bounding box size of the overlay; and training the model by inputting the input data set to a model for deep learning. The step of training the model may include a step of calculating a loss function by comparing result data predicted by the model with the label data; and a step of optimizing an algorithm of the model by modifying a weight of the model so that a loss value calculated with the loss function may become smaller than a reference value.

Abstract: There is provided a deep learning-based overlay key centering system and a method thereof that may precisely measure and examine an alignment state of fine patterns of a semiconductor substrate. The method includes collecting an input data set from at least one device, the input data set comprising measurement image data of an overlay key and label data including information on a position and bounding box size of the overlay; and training the model by inputting the input data set to a model for deep learning. The step of training the model may include a step of calculating a loss function by comparing result data predicted by the model with the label data; and a step of optimizing an algorithm of the model by modifying a weight of the model so that a loss value calculated with the loss function may become smaller than a reference value.

Abstract: A method of centering a correlation-based overlay includes resizing an overlay target image to a size smaller than an entire image size, defining first and second templates that are symmetrical to each other based on a diagonal in the resized image, and calculating a rough center coordinate by calculating a first correlation value representing a similarity symmetrical with respect to the diagonal between images of the first and second templates; defining first and second templates symmetrical based on a diagonal passing through the rough center coordinates in an original image of the overlay target image, calculating a fine center coordinate of the overlay target image by calculating a second correlation value representing a similarity symmetrical with respect to the diagonal between the images of the first and second templates; and centering an overlay key by moving a stage to a target position based on the fine center coordinates.