LINE WIDTH ERROR OBTAINING METHOD, LINE WIDTH ERROR OBTAINING APPARATUS, AND INSPECTION SYSTEM

摘要

Optical image data is acquired by irradiating a pattern with light emitted from a light source. A threshold value is specified by internally dividing a minimum value and a maximum value of a signal amount of reference image data by a division ratio. A position corresponding to a signal amount of a threshold value is determined as an edge of a pattern of the reference image data. A position of a signal amount equal to the threshold value is determined as an edge of the pattern of the optical image data. A line width error is obtained as a difference between a first line width of the optical image data and a second line width of the reference image data. A new threshold value is specified in the case of fluctuation of a light quantity of the light source or decrease of a contrast value of the optical image data.

主权项

1. A line width error of a pattern formed in a sample obtaining method comprising:
acquiring optical image data of a pattern formed in a sample by irradiating the pattern with light emitted from a light source, and causing the light transmitted through the sample or reflected by the sample to be incident on a sensor; generating reference image data corresponding to the optical image data from design data of the pattern; specifying a threshold value by internally dividing a minimum value and a maximum value of a signal amount of the reference image data by a division ratio, and determining a position corresponding to the signal amount of the threshold value as an edge of the pattern of the reference image data; determining a position of the signal amount equal to the threshold value as an edge of the pattern of the optical image data, and detecting an edge pair consisting of an edge as a starting point for a measurement of a first line width of the pattern, and another edge as an ending point of the measurement of the first line width; obtaining the first line width of the pattern using the edge pair of the optical image data, and obtaining a line width error as a difference between the first line width and a second line width of the pattern obtained using an edge pair of the reference image data corresponding to the edge pair of the optical image data; and wherein a new threshold value is specified in the case of fluctuation of a light quantity of the light source or decrease of a contrast value of the optical image data, and a position of the signal amount equal to the new threshold value is determined as an edge of the pattern of the optical image data.