Monitoring of process chamber

A method for controlling a wet processing system, comprising:

• dispensing, with a spray nozzle, a chemical solution into a processing chamber;
• injecting one or more illumination markers into the processing chamber;
• illuminating, with an illumination device, the processing chamber;
• obtaining a plurality of sets of images representing locations of the one or more illumination markers, wherein each set of the plurality of sets of images is obtained at a same time point;
• determining a trajectory of an illumination marker of the one or more illumination markers based on the plurality of sets of images;
• determining whether the determined trajectory is within a predetermined trajectory range;
• in response to the determined trajectory being within the predetermined trajectory range, maintaining one or more process parameters of the wet processing system;
• and
• in response to the determined trajectory being outside the predetermined trajectory range, adjusting the one or more process parameters of the wet processing system.

A wet processing system, comprising:

• a processing chamber;
• a spray nozzle positioned within the processing chamber and configured to dispense a chemical solution over one or more wafers;
• one or more chemical distribution lines configured to inject one or more illumination markers into the processing chamber;
• one or more detectors positioned around the processing chamber and configured to obtain images representing locations of the one or more illumination markers;
• and
• a processing system configured to:
• determine a trajectory of an illumination marker of the one or more illumination markers based on the images;
• and
• determine whether the determined trajectory is outside a predetermined trajectory range;
• and
• in response to the determined trajectory being outside the predetermined trajectory range, adjust one or more process parameters associated with the wet processing system.