US Patent 9236340 String selection structure of three-dimensional semiconductor device

A three-dimensional semiconductor device includes first and second selection lines stacked one on the other. An upper line horizontally crosses over the first and second selection lines. First and second vertical patterns vertically cross the first and second selection lines. The first and second vertical patterns are connected in common to the upper line. Each of the first and second vertical patterns constitutes first and second selection transistors that are connected in series to each other. The first selection transistors of the first and second vertical patterns are controlled by the first and second selection lines, respectively.