A memory card structure comprising a substrate, a plurality of memory chips, some molding compound and an ultra-thin plastic shell is provided. To fabricate the memory card, a substrate having a first surface and a second surface is provided. The first surface has a plurality of outer contacts and the second surface has a cavity and a plurality of inner contacts around the cavity. The outer contacts and the inner contacts are electrically connected to each other. The memory chips are stacked up in the same area inside the cavity. Furthermore, the memory chips are electrically connected to the inner contacts. Then, the memory chips and the inner contacts are encapsulated. Thereafter, the ultra-thin plastic shell is placed over the second surface and attached to the substrate. That portion of the ultra-thin plastic shell covering the memory chips has a thickness of about 0.1.about.0.4 mm.