Embodiments herein describe techniques for fuse lines and plugs formation. A semiconductor device may include a fuse line having a nominal fuse segment abutted to a necked fuse segment. The nominal fuse segment may be wider than the necked fuse segment. A first spacer may be along a first side of the fuse line and a second spacer along a second side opposite to the first side of the fuse line. The first spacer may include a part having a width at least twice a width of a part of the second spacer. A plug within a vicinity of the necked fuse segment may have a plug width that may be at least twice a plug with of a plug of an interconnect line outside the vicinity. Other embodiments may also be described and claimed.