An integrated circuit semiconductor device includes a first region including first active fins extending in a first direction, and first transistors including first gate electrodes extending in a second direction, a second region in contact with the first region in the second direction, wherein the second region includes second active fins extending in the first direction, and second transistors including second gate electrodes extending in the second direction. The integrated circuit semiconductor device includes metal dams at a boundary of the first region and the second region to separate the first gate electrodes and the second gate electrodes in the second direction, wherein the metal dams, the first gate electrodes, and the second gate electrodes are electrically connected in the second direction.