depending on how R and C net out.

• Shape length matters: for short shapes the resistance contribution is small compared with capacitance, so widening a short shape increases delay more, whereas for a longer shape the resistance reduction offsets the capacitance rise so the RC increase is smaller.
• From a lower-node perspective, at 7nm and below cross-layer coupling capacitance becomes the dominant factor.

KEY Wider wire lowers R but raises C - delay change depends on RC, with length and node coupling deciding the result.

M3 Antenna Violation Cases

• Case 1 has an issue because it has a jumper.
• Cases 2 and 3 also have issues, since an antenna violation occurs when the longest single metal layer is directly connected to a gate terminal, as in case 2.
• For case 3 the ratio of metal area to gate area must be below the allowable ratio, where allowable ratio = allowable metal area / gate area. Here it is (25 x 5) / 1 = 125, and since 125 exceeds the allowable ratio, an antenna violation results.

KEY Antenna violations arise when a long single metal connects to a gate; check the metal-to-gate area ratio.

Why Metal Thickness Increases Upward

Fabricating thicker layers requires greater spacing between adjacent metal lines. Lower metal layers are made thinner so their pitch can be kept as small as possible. This is necessary because the lower metal layers must connect to dense pins. If the lower layers were thick, their pitch would grow, and a