| 摘要 |
<p>PURPOSE:To enable a wafer ring to be changed smoothly by providing a moving table which holds a support piece and which can move in the same direction as a pushup rod, and further providing a part with which the pushup rod comes in contact when the rod retracts by a predetermined amount. CONSTITUTION:When changing a wafer ring 23, a pulse motor is so controlled that a contact position of a roller 4 with respect to a cam 2 can move over a range from a point c to a point b. In this instance, as the came 2 revolves in the direction of an arrow A, a pushup rod 6 descends; during the decent, a bottom 6a of the pushup rod 6 comes in contact with a contact part 14. Furthermore, by the revolution of the cam 2, a moving table 13 also descends with the descent of the pushup rod 6. When the contact position of the roller 4 with respect to the cam 2 has come to the point b, a support surface 10a descends below the support position of a wafer sheet 21. Hence, even if the wafer ring 23 is transferred horizontally, the wafer ring 23 and a support piece 10 will cause no interference. This enables the wafer ring 23 to be changed smoothly.</p> |
