The transient temperature profile across a commercial wafer temperature sensor device in an inductively coupled Ar plasma is reported. The measured teinperatures are compared to model predictions, based on a coupled plasma-wafer model. The radial temperature profile is the result of the radial profile in the ion energy flux. The ion energy flux profile is obtained by combining the Langmuir probe measurement, the ion wall flux probe measurement, and a plasma model. A methodology to estimate the ion flux profile using the sensor measurements has been validated by combining the plasma measurements, the wafer temperature measurements, and the plasma-wafer.model. It is shown that with minimal heat transfer between the wafer and the chuck, the initial transient wafer temperature profile after plasma ignition can be used to estimate the ion energy flux profile across the wafer. (C) 2007 American Vacuum Society