发明名称 |
MISSING OR BROKEN WAFER SENSOR |
摘要 |
Apparatus for sensing a missing or broken wafer in an automated wafer transfer system. The apparatus includes means for moving a wafer transfer mechanism from a first position along a prescribed path. A counter coupled to an oscillator is enabled when the wafer transfer mechanism and a wafer are moved away from the first position. A photosensor senses the presence of the wafer at a second position along the prescribed path and inhibits the counter. The count stored in the counter is compared with a predetermined count corresponding to the time required for movement of an unbroken wafer to the second position. If the counts do not agree, a missing or broken wafer is indicated and corrective action is taken. |
申请公布号 |
DE3380651(D1) |
申请公布日期 |
1989.11.02 |
申请号 |
DE19833380651 |
申请日期 |
1983.05.23 |
申请人 |
VARIAN ASSOCIATES, INC. |
发明人 |
VORA, MAHASUKH;MALHOTRA, RAJENDER |
分类号 |
H01J37/317;G01N21/88;G01N21/93;G01N21/956;H01L21/00;H01L21/265;H01L21/66;H01L21/67;(IPC1-7):H01L21/00 |
主分类号 |
H01J37/317 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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