In these years, attention is focused on nonvolatile semiconductor memory devices including memory cells three-dimensionally disposed in the nonvolatile semiconductor memory device for enhancing the integration degree of the nonvolatile semiconductor memory device.
One of the nonvolatile semiconductor memory devices including memory cells three-dimensionally disposed is a nonvolatile semiconductor memory device using a transistor in a columnar structure. The semiconductor memory device using the transistor in the columnar structure includes an electrode layer to be a gate electrode in multiple layers, a pillar channel body layer, and a memory film provided between the gate electrode and the channel body layer. The structure including the conductive layer, the channel body layer, and the memory film is called a memory string structure.
In this type of nonvolatile semiconductor memory device, one end of a memory string is individually connected to a plurality of read bit lines, and the other end of the memory string is connected to a common source line. In the case where the bit line is provided on the source line, a distance of a via electrode connecting the bit line to the memory string is inevitably made longer than a distance of a via electrode connecting the source line to the memory string.
In such a configuration, when the downscaling of the individual portions in a memory cell advances, it is sometimes difficult to electrically connect the memory string to the other interconnections connected to the memory string (the bit line, for example).
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