Performance Evaluation of RF Generators with In-Situ Plasma Process Monitoring Sensors

Plasma-processing equipment consists of numerous components, and RF power delivery system is one of the most critical for maintaining the requisite wafer quality. In this research, we investigate the use of In-Situ plasma process monitoring sensors to evaluate the performance of the RF generator used in plasma enhanced chemical vapor deposition (PECVD) equipment. We employ three kinds of In-Situ plasma process monitoring sensors, optical emission spectroscopy (OES), an optical plasma-monitoring sensor (OPMS), and a voltage-current (VI) probe, to monitor the plasma conditions produced by three different RF generators (RFGs). We found no significant differences among the test wafers. Thus, we conclude that the three RFGs each perform similarly in the PECVD system. We also found the OES is useful for analyzing the plasma chemistry and the degree of dissociation and ionization, the OPMS to be useful for monitoring the long-term stability in plasma processing, and the VI probe to be helpful for detecting instantaneous faults in semiconductor manufacturing.