A semiconductor device includes a plurality of capacitors disposed on a substrate and a support pattern supporting upper portions and lower portions of the capacitors. Each of the capacitors includes a lower electrode, an upper electrode, and a dielectric layer between the lower and upper electrodes. The lower electrode includes a first electrode portion electrically connected to the substrate and having a solid shape and a second electrode portion stacked on the first electrode portion and having a shape comprising an opening therein. The support pattern includes an upper pattern contacting sidewalls of top end portions of the lower electrodes and a lower pattern vertically spaced apart from the upper pattern. The lower pattern contacts sidewalls under the top end portions of the lower electrodes.