| 摘要 |
<p>PURPOSE:To prevent foreign substances from adhering to semiconductor wafers on a stage by a method wherein a cylindrical cover to expand and contract following the vertical operation of the stage is mounted between the peripheral edge of the stage and the peripheral edge of the opening of a conveying port. CONSTITUTION:A cylindrical cover 11 is mounted between the peripheral edge of a stage 3 and the peripheral edge of the opening of a conveying port 2. This cover 11 is constituted in such a way as to expand and contract following the vertical operation of the stage 3 and expands and contracts by making the stage 3 move vertically. Accordingly, dust can be prevented from intruding onto the stage 3 from the interior of a case body 1 at the time of vertical movement of the stage. Thereby, even though foreign substances peeled from the inner surface of the case body 1, dust scattered by the crack and so on of semiconductor water and metal powder from a screw shaft 9 or a solid material due to an oil fly up on the stage 3, the foreign substances can be prevented from adhering to the semiconductor wafers in a cassette.</p> |
