| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum processing device for detecting a missing article during transportation, a gate valve with a sensor for detecting the missing article during transportation, and a method for detecting the missing article during transportation. SOLUTION: A reflective photosensor 41 comprising seventeen unit sensors 43 is set through a glass window at a ceiling opening of a valve element of a gate valve coupling a carrying chamber 10 and a sputtering chamber 13 of a vacuum processing device. The reflective photosensor 41 is a line sensor where the seventeen unit sensors 43, each having a light projecting part 44 and a light receiving part 45, are arranged in the widthwise direction perpendicular to the carrying direction of a wafer W. Between leading end and trailing ends of the wafer W passing directly under the sensor 41, the respective unit sensors 43 are synchronized, and light being projected, at a period of 1 msec, from the light projecting part 44 and received at the light receiving part 45 after being reflected on the wafer W is counted. The presence of a missing part is determined by comparing a light receiving pattern formed from counts of respective unit sensors 43 with a similar light receiving pattern of a normal wafer. COPYRIGHT: (C)2003,JPO |
