A nitride hard mask is used to isolate active areas of a DRAM cell. On the bottom surface of the layered substrate, there are provided a plurality of functional terminals for inputting and outputting signals relating to functions of a circuit inside the layered substrate, a plurality of ground terminals, a plurality of terminals that are not connected to external circuits, and a conductor section for grounding. The protective environment in one form is a flexible polyvinyl chloride of at least \xbd mil in thickness.