DETECTION METHOD OF SMALL PARTICLE ON APPROXIMATELY SMOOTH REFLECTING SURFACE BY LASER REFLECTION PICKUP UNIT

摘要

PROBLEM TO BE SOLVED: To provide a leakage particle detection system capable of acquiring an accurate, reproducible, thereby measurable and predictable result, and detecting a single fine particle unfindable by human visual sensation. SOLUTION: In this method and a device, a leakage particle on an approximately smooth surface 17 is detected by measuring the quantity of parallel light reflected by a clean part on the surface 17 and the quantity of parallel light reflected by the particle on the surface 17. In the method and the device, a light pickup 10 similar to that for DVD or for CD can be used, and thereby a hollow defect can be also detected. COPYRIGHT: (C)2006,JPO&NCIPI