Abstract: A method for polishing a wafer effectively preventing a sag in an outer peripheral portion of a wafer and a polishing pad for polishing a wafer preferably used in the method for polishing a wafer are provided. The method for polishing a wafer comprises the step of: mirror-polishing a wafer with a main surface of the wafer being in contact with a polishing pad of non-woven fabric impregnated with resin, wherein a ratio of surface roughness of the polishing pad to compressibility thereof {surface roughness Ra (?m)/compressibility (%)} is 3.8 or more.

Abstract: A polishing cloth is adhered to a polishing belt including a window opening for end-point detection. A transparent film, including a liner, that transmits end-point detection light is adhered to a portion of the polishing cloth corresponding to the window opening of the polishing belt. Another liner is adhered via an adhesion layer to the adhesion surface of the polishing cloth at area other than the portion corresponding to the window opening. The polishing cloth includes the transparent film that transmits the end-point detection light at the portion corresponding to the window opening of the polishing belt so that an end point of the surface of the object to be polished can be detected through the transparent film. This prevents slurry to leak inside the belt compared to the conventional technology.

Abstract: 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.