Structures of electronic fuses (e-fuse) are provided. An un-programmed e-fuse (100) includes a via (120) of a first conductive material having a bottom and sidewalls with a portion of the sidewalls being covered by a conductive liner (121) and the bottom of the via being formed on top of a dielectric layer (410), and a first and a second conductive path (111, 112) of a second conductive material formed on top of the dielectric layer (410) with the first and second conductive paths being conductively connected through, and only through, the via (120) at the sidewalls. A programmed e-fuse includes a via (120); a first conductive path (111) at a first side of the via and being separated from sidewalls of the via by a void (122); and a second conductive path (112) at a second different side of the via (120) and being in conductive contact with the via through sidewalls of the via.