Semiconductor memory device including multiple conductive line layers

Disclosed is a semiconductor memory device comprising a plurality of memory cells each including an access transistor, a pull-up transistor, and a pull-down transistor on a substrate, a first line layer on the memory cells and including a first lower landing pad and a second lower landing pad, a second line layer on the first line layer and including a ground line having an opening and an upper landing pad in the opening, and a third line layer including a word line on the second line layer. The ground line is electrically connected through the first lower landing pad to a terminal of the pull-down transistor. The word line is electrically connected through the upper landing pad and the second lower landing pad to a terminal of the access transistor.