Calibration device

A method comprising:

• providing a first tray shield that is usable, the first tray shield having a first inner chamber into which a first calibration ring is placeable, and the first tray shield being in a ring shape;
• rotating the first calibration ring inside the first inner chamber to remove metal particles or burrs on the first inner chamber;
• and
• loading a wafer into the first inner chamber to process the wafer.

A method comprising:

• detecting that a first calibration ring is placeable into a first inner chamber, a second inner chamber and a third inner chamber of a tray shield, respectively, the first inner chamber, the second inner chamber and the third inner chamber each being in a ring shape, and the tray shield being for wafer processing;
• moving around the first calibration ring inside the first inner chamber, the second inner chamber and the third inner chamber, respectively, to remove metal particles or burrs on the first inner chamber, the second inner chamber and the third inner chamber;
• and
• loading wafers into the first inner chamber, the second inner chamber and the third inner chamber to process the wafers.