1460011148-790abd67-5cc2-4f2a-b8ca-7bcc4cdf66ff

Techniques are provided for erasing memory cells in a 3D stacked non-volatile memory device in a way which avoids prolonging erase time as the erase speed deceases due to the accumulation of program-erase cycles. The outer side surface includes a plurality of closed band-shaped regions arranged in the lengthwise direction of the spark plug, within each of which a plurality of identical marks, which represent the same piece of information concerning the spark plug, are formed at predetermined intervals in a circumferential direction of the spark plug. A drain contact has a head connected substantially perpendicularly to a stem. The method further comprises forming columns of the contact plugs by removing the sacrificial interlayer film, forming an interlayer insulating film overall, and partially removing the interlayer insulating film from above the surface thereof to expose the surfaces of the capacitor contact plugs.