A process of fabricating a stack capacitor includes the following steps. First of all, multiple energy storage units having respective first electrodes and second electrodes at opposite sides are provided. These energy storage units are then stacked to have the first electrodes contact with each other and the second electrodes contact with each other, wherein the energy storage units are initially positioned by a fastening member. Next, the first electrodes are bonded together via a first conductive layer and the second electrodes are bonded together via a second conductive layer, thereby fabricating the stack component.