Vertical nonvolatile memory devices having reference features

1. A memory device comprising:

a substrate having a defined cell array region;

a dummy pattern disposed on the substrate near an edge of the cell array region; and

a plurality of vertically stacked conductive lines on the substrate, covering the dummy pattern and having a surface variation at a crossing of the dummy pattern that indicates a position of the underlying dummy pattern.

2. The memory device of claim 1 , wherein the dummy pattern comprises a trench.

3. The memory device of claim 1 , wherein the substrate further comprises a connection region disposed adjacent the cell array region and a peripheral circuit region disposed adjacent the connection region on a side thereof opposite the cell array region, wherein circuits for driving a cell array are disposed in the peripheral circuit region, and wherein the plurality of conductive lines are connected to the circuits of the peripheral circuit region by wiring lines in the connection region.

4. The memory device of claim 3 , wherein the conductive lines have a stepped structure in the connection region.

5. The memory device of claim 4 , further comprising a plurality of contact plugs in the connection region, respective ones of which contact respective terminations of the conductive lines.

6. The memory device of claim 1 , when the dummy pattern comprises a first dummy pattern, the vertical nonvolatile memory device further comprises at least one second dummy pattern disposed in the connection region adjacent the peripheral circuit region which is configured as a reference point for measuring locations of terminations of the conductive lines.

7. The memory device of claim 6 , wherein the at least one second dummy pattern has the same structure as a structure formed in the peripheral circuit region.

8. The memory device of claim 6 , wherein the first dummy pattern and the second dummy pattern are electrically isolated.

9. The memory device of claim 1 , further comprising a plurality of spaced apart memory cell strings extending vertically from the substrate and comprising respective spaced apart channel regions extending vertically from the substrate in the cell array region and controlled by the plurality of conductive lines.

10. The memory device of claim 9 , wherein the plurality of conductive lines serve as gate lines of transistors of the memory cell strings.

11. A memory device comprising:

a substrate;

a dummy structure on or in the substrate near a boundary of a connection region of the substrate;

a vertical channel region disposed on the substrate in a cell array region of the substrate; and

a plurality of vertically stacked conductive gate lines with insulating layers interposed therebetween, the conductive gate lines and interposed insulating layers disposed laterally adjacent the vertical channel region and extending across the dummy structure, at least an uppermost one of the conductive gate lines and insulating layers having a surface variation at the crossing of the dummy structure configured to serve as a reference feature.

12. The memory device of claim 11 , wherein the dummy structure comprises a trench and wherein the surface variation comprises an indentation overlying the trench.

13. The memory device of claim 11 , wherein terminations of the conductive gate lines are stepped.

14. The memory device of claim 13 , further comprising a second dummy structure disposed near an edge of the connection region opposite the cell array region.

15. The memory device of claim 14 , wherein the second dummy structure comprises a dummy trench, a dummy resistor or a dummy gate structure.