A semiconductor fabrication system includes a wafer carrier configured to carry a wafer thereon. A radiation source is positioned above the wafer carrier. The radiation source is configured to emit thermal radiation. A plurality of reflectors is positioned above, and aligned with, an edge region of the wafer. The reflectors each have a reflective coating configured to reflect the thermal radiation. A plurality of separately-controllable motors is coupled to the reflectors, respectively. The motors are each configured to cause its respective reflector to rotate in a counterclockwise direction or a clockwise direction so as to redirect the thermal radiation back toward the edge region of the wafer. A controller is communicatively coupled to the plurality of motors. The controller is configured to control each of the motors separately to cause each motors to rotate independently of other motors.