Interconnect fuse structures including a fuse with a necked line segment, as well as methods of fabricating such structures. A current driven by an applied fuse programming voltage may open necked fuse segments to affect operation of an IC. In embodiments, the fuse structure includes a pair of neighboring interconnect lines equidistant from a center interconnect line. In further embodiments, the center interconnect line, and at least one of the neighboring interconnect lines, include line segments of lateral widths that differ by a same, and complementary amount. In further embodiments, the center interconnect line is interconnected at opposite ends of a necked line segment. In further embodiments, the necked line segment is fabricated with pitch-reducing spacer-based patterning process.