A device and method for thermally treating substrates. A substrate is heated by a heating plate to improve thermal homogeneity. The heating plate is heated using a number of separately controlled heating elements. The temperature of the heating elements is measured and the heating process is controlled by a PID controller. In addition, the temperature of the substrate surface facing away from the heating plate is locally measured. The temperature distribution over the substrate surface is determined according to the measured temperatures and set values for the temperature of the individual heating elements are determined and transmitted to the PID controller.