This paper predicts self-heating effect in a short intra-block wire will arise as a design issue with technology scaling. The short intra-block wires are close to the substrate and thought to have good thermal radiation characteristic, however, we reveal that the self-heating of short wires will be more significantly than that of global wires, and it can cause a reliability and performance degradation in the future. The max temperature rise from the ambient temperature becomes 27.3C in a 14 nm process. Our attribution analysis also clarifies that shrinking wire cross-sectional area as well as low-k material and increased power dissipation deteriorates self-heating. Experimental results also reveal that the self-heating of local wires will be getting worse than repeater-inserted global wires.