An eFuse structure of a semiconductor device may include a first metal formed at a first level on a substrate, a second metal formed at a second level between the first level and the substrate, a third metal formed at a third level between the second level and the substrate, a first via connecting the first metal to the second metal, and a second via connecting the second metal to the third metal. The first metal may include a first portion extending in a first direction, a second portion extending in the first direction and being adjacent to the first portion, and a third portion connecting the first portion to the second portion. A first distance between the first portion and the second portion may be greater than a width of the second portion in a second direction perpendicular to the first direction.