摘要 |
An ion implanter for implanting ions into a batch of semiconductor wafers comprises a wafer holding disk of the centrifugal holding type, and a plurality of wafer rests in the wafer holding disk having a wafer holding surface which is conically curved. When the wafer holding disk is rotated, the wafer is pushed onto the wafer holding surface so that the surface of the wafer is curved nearly in the same manner as the conically-curved inner surface of the peripheral portion of the s wafer holding disk As a result, an ion beam being irradiated upon the surface of the wafer is always perpendicular to the surface of the wafer.
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