This paper presents the application of ripple pyrometry on AG Associates Integra systems which are three phase powered and multi-zone controlled rapid thermal CVD cluster tools. Two types of sensor configurations were explored for optimum emissivity compensated temperature measurement performance. It was found that it is very difficult to measure temperature when a two sensor configuration is used due primarily to the chamber and reflector architecture. Good temperature measurement was obtained at high temperatures when zone ratios between the wafer and lamp sensors were aligned. It was also found that the temperature signal to noise ratio is very sensitive to ripple quality and zone ratio alignment accuracy.