what are interconnects why metal lines vias barriers matter

INTERCONNECTS are the metal wires (lines) and the vertical connections (VIAS) that carry signals and power between the billions of transistors. Two big reliability/cost concerns a GPS engineer cares about: 1) RC DELAY — as wires get thinner and longer, their resistance (R) and capacitance (C) go up, slowing the signal; this is why copper replaced aluminum (lower resistivity) and why metal choice matters. 2) ELECTROMIGRATION — at high current density, the moving electrons physically push metal atoms, creating voids/opens or hillocks that eventually break the wire; it's a leading reliability failure. WHY GPS CARES: interconnect failures are top field issues (opens, shorts, reliability). And this connects to your metal-deposition work — barriers/liners (Lesson 57) and void-free fill exist to protect interconnects. The one-line frame: 'Interconnects are the city's streets — and electromigration is how the traffic destroys the road over time.'