WCVD SPRINT Recipe Optimization to Eliminate Abnormal Profile

AMAT Centura SPRINT chamber encounters abnormal resistivity (Rs) profile intermittently. This effect is seen even with controlled purge ring kit height which helps to minimize the issue by improving edge gases flow. The recipe parameters were studied and by experimenting with the throttle valve (T/V) step value during one of the process recipe steps it able to observe the difference in RS profile result. The T/V opening step was found to affect the wafer backside pressure chucking and de-chucking condition. The root cause of profile Rs abnormal is stemming from wafer de-chucking caused by big T/V step opening. By implementing new T/V step values it can minimize the de-chucking effect and improve wafer resistivity uniformity.