Optimal tuning of epitaxy pyrometers

Epitaxy is a process strongly dependent on wafer temperature. Unfortunately, the performance of the pyrometers in charge of sensing wafer temperature deteriorate with the usage. This represents the major maintenance issue for epitaxy process engineers who have to frequently calibrate pyrometers emissivity coefficient. At the present state the change of the emissivity coefficient is heuristically based on fab tradition and process engineers experience. We present a statistical tool to map the relationship between change in the temperature readings and emissivity adjustments. The module has been tested on real industrial dataset.