A process and device for manufacturing a primary unit pack of a wafer. This fixing device comprises a heat-fixing roller having an elastic layer and a heat source; and a pressurizing unit having an elastic member with a flat surface for pressing an endless member. Further, a memory cell has n capacitors with different capacitances and the n capacitors are each connected to a corresponding one of n data lines, so that a variety of the storage capacitances can be obtained and multilevel data can be stored. The system provides a way of returning some used energy back into the system for reuse.