An IC device includes an interlayer dielectric (ILD), a first tower structure embedded in the ILD, and a first ring region including a portion of the ILD that extends around the first tower structure. The first tower structure includes a plurality of first conductive patterns in a plurality of metal layers, and a plurality of first vias between the plurality of metal layers along a thickness direction of the IC device. The plurality of first conductive patterns and the plurality of first vias are coupled to each other to form the first tower structure. The plurality of first conductive patterns is confined by the first ring region, without extending beyond the first ring region. The first tower structure is a dummy tower structure.