Abstract: A wafer holder is provided which properly protect backside of a wafer, especially when frontside of the wafer is processed, from pollution and mechanical injury. The wafer holder includes a wafer support section having a hole for locating a wafer, a cover covering the wafer but any chip on the wafer is not touched with the cover; one or more fastening devices for fastening the cover on the wafer support section, each the fastening device having a fixed terminal and a movable terminal where the fixed terminal locates on the wafer support section and the movable terminal presses the cover on the wafer support section. Addition, the wafer support section can be part of chamber wall and then it is an optional part of the present wafer holder.