Use of wafer brightness to monitor laser anneal process and laser anneal tool

A method is provided for monitoring the laser annealing a wafer of bare silicon 10. After annealing images of many regions of the wafer are captured and the surface brightness of these regions is measured using a camera 20. Statistics of these surface brightness measurements are determined, such as their mean or their standard deviation. The surface brightness statistics can be used to monitor the annealing laser tool, either during the annealing process of following maintenance. Also disclosed is a method of using a correlation between the surface brightnesses and the electrical resistance of the annealed wafer to determine whether the annealing process resulted in a wafer that meets end user specifications. The brightness statistics identify spatial differences caused which scanning the laser across the silicon and altering the focus of the laser to correct the differences.