A device for use in a thermal annealing process for a wafer (T) of material chosen among the semiconductor materials for the purpose of detaching a layer from the wafer at an weakened zone. During annealing, the device applies (1) a basic thermal budget to the wafer, with the basic thermal budget being slightly inferior to the budget necessary to detach the layer, this budget being distributed in an even manner over the weakened zone; and (2) an additional thermal budget is also applied to the wafer locally in a set region of the weakened zone so as to initiate the detachment of the layer in this region.