Patent ID: 9341465
Filing Date: 2016-05-17
CPC Classification: G01B

Claim Text:
1. A dimension measuring apparatus, in which a low-magnification field of view is formed while a high-magnification field of view being narrower than the low-magnification field of view is formed within the low-magnification field of view, and a workpiece on a stage is photographed with different photographing magnifications to measure a dimension of the workpiece, the apparatus comprising: a movable stage that is movable in XY directions; a measurement setting data storing section that holds feature amount information for detecting a workpiece from a photographed image, the feature amount information being a pattern image based on a first master image photographed with a low magnification, measured position information showing a position to be measured which is designated as an object to be measured, the measured position information set based on a second master image with a high magnification, and design value information formed of a design value set with respect to each position to be measured and a tolerance associated with the design value; a low-magnification imaging section that photographs, with the low magnification, the workpiece within the low-magnification field of view, to generate a low-magnification image; a workpiece detecting section that specifies a position and a posture of the workpiece in the low-magnification image based on the feature amount information; a stage controlling section that controls the movable stage based on the specified location and posture such that the position to be measured of the workpiece stays within the high-magnification field of view; a high-magnification imaging section that photographs, with the high magnification, the position to be measured which has moved into the high-magnification field of view, to generate a high-magnification image, wherein center of the high-magnification field of view coincides with center of the low-magnification field of view; an edge extracting section that extracts an edge of the position to be measured from the high-magnification image based on the measured position information; a dimension value calculating section that obtains a dimension value of the position to be measured based on the extracted edge; and a quality determining section that compares a difference made between the dimension value calculated by the dimension value calculating section and the design value corresponding thereto, with the corresponding tolerance, to perform quality determination on the dimension value with respect to each position to be measured, wherein in the case of the presence of two or more workpieces that cannot stay within the high-magnification field of view, the stage controlling section sequentially moves the movable stage with respect to these workpieces such that positions to be measured stay within the high-magnification field of view.