Abstract: A method and apparatus that provides process monitoring within a semiconductor wafer processing system using multiple process parameters. Specifically, the apparatus analyzes multiple process parameters and statistically correlates these parameters to detect a change in process characteristics such that the endpoint of an etch process may be accurately detected, as well as detecting other characteristics within the chamber. The multiple parameters may include optical emissia, environmental parameters such as pressure and temperature within the reaction chamber, RF power parameters such as reflected power or tuning voltage, and system parameters such as particular system configurations and control voltages.