APPARATUS FOR RETAINING WORKPIECE AND ITS MAKING METHOD

摘要

A retaining device retains a workpiece to allow the workpiece to slide against a polishing pad located on a polishing board opposed to the retaining device. The retaining device includes a plate including a permeable portion and a seal portion having a lower permeability and provided around an outer periphery of the permeable portion. By absorbing air toward a first surface of the permeable portion, the workpiece is attached and attracted to a second surface of the permeable portion opposite to the first surface. The retaining device further includes a retainer ring provided on an outer peripheral portion of the plate for preventing an outer edge of the workpiece from being overhung by polishing; and a backup ring located between the plate and the retainer ring for putting the retainer ring into pressure contact with the polishing pad. Since the workpiece can be attached and attracted to or released from the plate by a simple operation, the time required for retaining the plate is shortened. Further, the damage to other machines and equipment used for workpiece retaining which is caused by the polishing liquid is alleviated, and thus the maintenance of such machines and equipment becomes easier. Moreover, the flatness of the polished workpiece is improved.