Patent attributes
Methods and systems for detecting wafer shift/slide in a semiconductor process chamber have been disclosed. The vibration amplitude is measured in terms of acceleration because an increase in vibrational acceleration correlates with an increase of displacement of a wafer. The vibration of a chamber is measured. External vibratory forces acting on the chamber may be transmitted to the wafer inside the chamber. The methods/systems determine if there is a net resultant force that may cause an unconstrained wafer to move from its original position in a chamber by measuring the relative chamber vibrations in three orthogonal directions. A tri-axial or three uni-axial accelerometers are mounted on a preferably exterior wall of the chamber to measure its vibration amplitude. The signal obtained as a function of time is then compared against a predetermined alarm amplitude to provide notification for corrective action.
