In-situ wafer stress measurement by chromatic confocal sensor scanning with vibration compensation

A system comprising:

• a process chamber;
• a transport chamber connected to the process chamber via a slot valve, wherein the slot valve is operable between an open position, in which the transport chamber is in fluid communication with the process chamber, and a closed position, in which the process chamber is sealed from the transport chamber;
• a robot arm configured to support a workpiece and move the workpiece along a movement path between the process chamber and the transport chamber with the slot valve in the open position;
• a chromatic confocal sensor configured to measure a wavelength of light reflected by the workpiece as the robot arm moves the workpiece along the movement path;
• and
• a processor in electronic communication with the chromatic confocal sensor, wherein the processor is configured to:
• receive a first scanning signal from the chromatic confocal sensor based on the wavelength of the light reflected by the workpiece as the robot arm moves the workpiece from the transport chamber to the process chamber;
• filter the first scanning signal to produce a first filtered signal that compensates for vibrations of the robot arm while the robot arm moves the workpiece from the transport chamber to the process chamber;
• and
• generate a first bow profile of the workpiece based on the first filtered signal.