Characterization of thin carbonized photoresist layer and investigation of dry strip process through real-time monitored variable temperature control

Dry-strip process of ion-implanted photoresist is a major challenging process due to prevent resist popping. We preheat the wafer at various temperatures in order to monitor the strip process steps between ion-implanted crust and bulk photoresist. It is found that the strip rate gets slower for low temperature, showing its high chemical reactive dependence. Temperature of wafer and optical emission spectrum were measured simultaneously during the strip process in real-time, in-situ. The presented results demonstrate that two measurements are well matched to classify the process step in terms of time. Temperature changes were observed in all cases of resist popping due to a photo-thermal effect via carbon residues left on wafer. This opens the possibility of monitoring resist popping in real-time, in-situ by measuring the temperature of wafer.