SEMICONDUCTOR DEVICES AND DATA STORAGE SYSTEMS INCLUDING THE SAME

A semiconductor device includes a first semiconductor structure including a first substrate, and a lower bonding structure on the first substrate, and a second semiconductor structure including a second substrate, and an upper bonding structure bonded to the lower bonding structure. The second semiconductor structure includes via patterns on the second substrate, a source contact pad including a material different from that of the second substrate, a source contact plug electrically connected to the source contact pad, a source contact via on the source contact pad, and an interconnection line that electrically connects the via patterns to the source contact plug. Lower surfaces of the via patterns are farther from the first substrate than a lower surface of the source contact via, and an upper surface of the second substrate is farther from the first substrate than an upper surface of the source contact pad.