Patent ID: 7326993
Filing Date: 2008-02-05
Classification: H01L

Abstract:
1. A nonvolatile semiconductor memory comprising: a semiconductor layer; a plurality of semiconductor regions formed on the semiconductor layer; a plurality of device isolating regions extended in a column direction so as to isolate the semiconductor regions; a first interlayer insulator film formed above the semiconductor layer; a lower conductive plug filled in the first interlayer insulator film and connected to one of the semiconductor regions; a second interlayer insulator film formed on the lower conductive plug and the first interlayer insulator film; an upper conductive plug filled in the second interlayer insulator film and contacting with the top and a part of a side of the lower conductive plug, respectively; and an interconnect formed on the second interlayer insulator film contacting with the top of the upper conductive plug and extended in the column direction, wherein a length of the upper conductive plug along the column direction is longer than a length of the lower conductive plug along the column direction, and the length of the upper conductive plug alone a row direction is shorter than the length of the lower conductive plug along the row direction.