To measure the thickness and hydrogen content of an amorphous silicon, and to perform excimer laser annealing.

The system provides a substrate holding-device for holding a substrate, a measurement device which measures thickness and hydrogen content of the substrate, and a data base comprising hydrogen content threshold value, and a level of likely laser energy for a substrate having distinct thickness. The system judges whether the measured hydrogen content exceeds the hydrogen content threshold value. An automatic control system for the laser energy comprises a comparison means which offers the likely laser energy level according to it, and a laser equipment feeding laser energy to the substrate.