A capacitor structure including a substrate, a first electrode, a first dielectric layer, a second electrode, a second dielectric layer, a third electrode, and a stress balance layer is provided. The substrate has trenches and a pillar portion located between two adjacent trenches. The first electrode is disposed on the substrate, on the pillar portion, and in the trenches. The first dielectric layer is disposed on the first electrode and in the trenches. The second electrode is disposed on the first dielectric layer and in the trenches. The second dielectric layer is disposed on the second electrode and in the trenches. The third electrode is disposed on the second dielectric layer and in the trenches. The third electrode has a groove, and the groove is located in the trench. The stress balance layer is disposed in the groove.