Defect review system and method, and program
A system is provided that realizes both reduction in coordinate error and improvement in throughput and allows observation of a micro-defect. The system includes: a function of measuring an amount of displacement between preliminarily calculated coordinates and an actual specimen position; a function of optimizing a coordinate correction formula so as to minimize the amount of displacement from the measured amount of displacement; and a function of calculating variation of displacement between the preliminarily calculated coordinates and the actual specimen position by statistical processing. When a value of coordinate variation is sufficiently small with respect to the field of view of an image for observation, which is to be a defect observation image, the system acquires only the image for observation without performing acquisition of an image for search, which is to be a defect search image.
1. A defect review system moving a specimen to a coordinate position of a defect detected in a first coordinate system and observing the defect of the specimen in a narrow field of view with respect to a second coordinate system, comprising:
a displacement measurement section which measures an amount of displacement between the coordinate position of the defect in the first coordinate system and an actual specimen position in the second coordinate system;
a coordinate correction formula optimizer which optimizes a coordinate correction formula for performing conversion from the second coordinate system to the first coordinate system in a direction of minimizing the measured amount of displacement;
a variation amount calculator which performs statistical processing on a variation amount of the amount of displacement between the first coordinate system and the second coordinate system;
a variation amount evaluation section which evaluates the variation amount on the basis of the length of the narrow field of view; and
a sequence determining section which determines a sequence of a process of squiring a defect image on the basis of an evaluation result by the variation amount evaluation section, wherein
when the variation amount is smaller than a certain constant-fold product of the length of the narrow field of view, the sequence determining section determines the sequence of the process of acquiring the defect image so as to skip the process of acquiring an image for search for detecting the defect in a wide field of view and to perform a process of acquiring a defect image for observation in the narrow field of view.
2. A defect review system moving a specimen to a the defect of the specimen in a narrow field of view with respect to a second coordinate system, comprising:
a displacement measurement section which measures an amount of displacement between the coordinate position of the defect in the first coordinate system and an actual specimen position in the second coordinate system;
a coordinate correction formula optimizer which optimizes a coordinate correction formula for performing conversion from the second coordinate system to the first coordinate system in a direction of minimizing the measured amount of displacement;
a variation amount calculator which performs statistical processing on a variation amount of the amount of displacement between the first coordinate system and the second coordinate system;
a variation amount evaluation section which evaluates the variation amount on the basis of the length of the narrow field of view; and
a sequence determining section which determines a sequence of a process of acquiring a defect image on the basis of an evaluation result by the variation amount evaluation section; wherein
when the variation amount is larger than a certain constant-fold product of the length of the narrow field of view, the sequence determining section determines the sequence of the process of acquiring the defect image so as to perform a process of acquiring an image for search for detecting the defect in a wide field of view and to perform a process of acquiring, using a result thereof, a defect image for observation in the narrow field of view.
3. The defect review system according to claim 2 , further comprising
a variation amount updating section which extracts a defect position using the defect image for search acquired in the process of acquiring an image for search, reflects the defect position in the variation amount acquired by the variation amount calculator and thereby updates the variation amount,
wherein the sequence determining section determines the sequence of the process of acquiring the defect image using the updated variation amount acquired by the variation amount updating section.
4. The defect review system according to claim 3 , wherein
when the amount of displacement deviates by at least a prescribed extent from the variation amount,
the variation amount updating section prohibits updating of the variation amount.
5. A method of controlling a defect review system comprising a computing system moving a specimen to a coordinate position of a defect detected in a first coordinate system and observing the defect of the specimen in a narrow field of view with respect to a second coordinate system, comprising:
a displacement measurement step in which the computing system measures an amount of displacement between the coordinate position of the defect in the first coordinate system and an actual specimen position in the second coordinate system;
a coordinate correction formula optimization step in which the computing system optimizes a coordinate correction formula for performing conversion from the second coordinate system to the first coordinate system in a direction of minimizing the measured amount of displacement;
a variation amount calculation step in which the computing system performs statistical processing on a variation amount of the amount of displacement between the first coordinate system and the second coordinate system;
a variation amount evaluation step in which the computing system evaluates the variation amount on the basis of the length of the narrow field of view; and
a sequence determining step in which the computing system determines a sequence of a process of acquiring a defect image on the basis of an evaluation result by the variation amount evaluation section,
wherein when the variation amount is smaller than a certain constant-fold product of the length of the narrow field of view, the sequence determining section the process of acquiring an image for search for detecting the defect in a wide field of view and to perform a process of acquiring a defect image for observation in the narrow field of view, or
when the variation amount is larger than a certain constant-fold product of the length of the narrow field of view, the sequence determining section determines the sequence of the process of acquiring the defect image so as to perform a process of acquiring an image for search for detecting the defect in a wide field of view and to perform a process of acquiring, using a result thereof, a defect image for observation in the narrow filed of view.