| 摘要 |
<p>PURPOSE:To prevent a wafer from damaging and cracking, by providing a first sensor for sensing whether any object to be processed is stored in carriers or not and a second sensor for sensing whether the objects to be processed are stored properly in the carriers or not. CONSTITUTION:In a base 31 for placing carriers, provided are a first sensor 32 for sensing whether any wafer is stored in four carriers 2 or not, and a second sensor 33 for sensing whether any wafer W protruded from the carriers 2 is stored in the four carriers 2 or not. The optical axis of light, which extends from a light emitting element 32A to a light receiving element 32B in the first sensor 32, is made to be so positioned, as shown by a point 41, that when any wafer W is not stored in all carriers 2, the light emitted from the light emitting element 32A can be received by the light receiving element 32B, and when even one wafer is stored in one of the carriers 2, the light transmitted from the light emitting element 32A to the light receiving element 32B is intercepted by the wafer thereof.</p> |
