A semiconductor device includes lower electrodes, a first supporter structure including first supporter patterns interconnecting the lower electrodes, wherein side surfaces of the first supporter patterns and side surfaces of the lower electrodes that are exposed by the first supporter patterns at least partially define a first open region, the first supporter patterns being spaced apart from one another, the first open region extending among the first supporter patterns in a horizontal direction, a dielectric layer covering the first supporter structure and the lower electrodes, and an upper electrode on the dielectric layer. A distance between adjacent ones of the first supporter patterns is smaller than or equal to a pitch of the lower electrodes.