| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic focusing system having a quick control function capable of determining a focusing position from the image information of a sheet of frame, and capable of surely focusing with high accuracy even to a horizontal pattern image. SOLUTION: This automatic focusing system comprises a means for changing the focusing position by every raster scanning line, and a control means for determining the focusing position by comparing the image information of every scanning line, the scanning line is an oblique scanning line having both of a horizontal component and a vertical component to the chip array on a semiconductor wafer. A method composed of a first step for roughly but surely getting the focusing position, and a second step for detecting the focusing position with high accuracy, is applied. COPYRIGHT: (C)2004,JPO |
