THICKNESS MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a thickness measuring apparatus which can accurately measure the thickness even as for an object having a transparent film on a surface to be measured and moreover, eliminates possible damage to a subject. SOLUTION: The surface of a subject (e.g. wafer 10) is irradiated with slit light across the width thereof and photographed by a TV camera 13. A reflection image from the surface of a transparent film is identified by image processing to measure the position of the surface of the subject. The position of the rear of the subject is measured by a laser displacement meter 14 to calculate the thickness of the subject from the position of the surface of the wafer 10 and the position of the rear of the wafer 10.