USE OF THE TEMPERATURE-DEPENDENCE OF THE THERMA-WAVE TECHNIQUE AS A THERMOMETER

The therma-wave technique is widely used to monitor dose uniformity an d repeatability in ion implantation. It is also known that the therma- wave signal and related parameters can be affected by the wafer temper ature during implant and by the temperatures the wafer experiences aft er implantation. We will show the post implant dependence of therma-wa ve parameters on the temperature and duration of a low temperature (< 130 degrees C) anneal. This temperature dependence could be used to mo nitor the average temperature of a silicon wafer in a second process a fter the initial TW measurement. As an example, we will infer the aver age temperature during an implant into the back side of a wafer by obs erving the change in the previously measured front side TW parameters.