A non-volatile memory structure can include a substrate extending horizontally and a filling insulating pattern extending vertically from the substrate. A plurality of active channel patterns can extend vertically from the substrate in a zig-zag pattern around a perimeter of the filling insulating pattern, where each of the active channel patterns having a respective non-circular shaped horizontal cross-section. A vertical stack of a plurality of gate lines can each extend horizontally around the filling insulating pattern and the plurality of active channel patterns.