A preventive treatment method for a multilayer semiconductor wafer is described. In some embodiments, this may include dividing an object stored in the source tier into a plurality of segments, determining if the target tier is missing at least one of the segments, writing the missing segments to the target tier, and deleting the object from the source tier. This successfully saves the band width necessary for transfer of the draw data from a main processor to a graphic processor, and relieve the main processor from the process load. Finally, a stacked gate structure is constructed by the third conductive layer, the second dielectric layer, the first conductive layer, the conductive spacer and the first dielectric layer, in which a floating gate of the stacked gate structure is constructed by a remainer portion of the first conductive layer and the conductive spacer. The magnetocaloric elements are connected thermally two by two at their consecutive ends through the intermediary of a heat exchange mechanism in thermal contact respectively with the heat transfer fluid circulating in the first of the magnetocaloric elements and with the heat transfer fluid circulating in the second of the magnetocaloric elements.