| 摘要 |
<p>PURPOSE:To improve a wafer chuck in structure so as to lessen chips in yield loss caused by a pawl in contact with the surface of a wafer. CONSTITUTION:A wafer chuck is equipped with a stage 11 where a wafer 1 is placed, two or more pawls 12, and moving means 13 of the same number with the pawls 12. A groove 11a is provided to the stage 11 around its circumferential side face. A motor and a vertical moving mechanism are built in each moving means 13, and the pawl 12 is mounted on the moving means 13 through the intermediary of the vertical moving mechanism. The moving means 13 are fitted into the groove 11a and made to travel separately to move the pawls 12 to points on a wafer 1 where effective chips are not located, and the wafer 1 is clamped with the pawls 12 at the above points.</p> |
