MEASURING METHOD FOR DIMENSION OF LEAD FRAME

• Main Authors: NAKANISHI MINORU, HAMADATE SADAJI
• Format: Patent
• Language: English
• Published: 08.12.1998
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; SEMICONDUCTOR DEVICES; TESTING

PROBLEM TO BE SOLVED: To obtain a measuring method in which the dimension of the interval between inner leads can be measured simply and precisely, by a method wherein the width of a through part in a place at a prescribed distance along the direction of an inner lead from a tip-side end part is found by an image processing means. SOLUTION: The tip of every inner lead 162 at a lead frame and its connection part 167 are photographed by a CCD camera so as to be situated inside the same visual field. Image data obtained by photographing them is binarized at a prescribed slice level, and binarized image data is obtained. Out of the binarized image data, a through-part region which comes into contact with the circumference of a square inspection region in the measured number of pixels or higher and a through-part region which is not crossed at all with the inspection region are deleted from an object to be inspected, and contour coordinate data on at least one through-part region other than them is acquired. Then, on the basis of the contour coordinate data, coordinate data on a starting point for a positioning operation to measure the width of the through-part region is obtained. Then, the width of the through-part region in a prescribed position is computed, and the interval between inner leads is decided.