Performance and Reliability Wiring dominates performance not transistors. Clock frequencies of 1 GHz act like microwave circuits with the leading edge components at 10 GHz. We'll see more clock multipliers for local clock control. Cross talk, parasitics and RC delays affect signal integrity at these speeds and even physical propagation of signals is an issue. Inductance of leads may actually limit speed and force a change in packaging.
Customer needs drive reliability.
There are more stringent requirements because of the increased wiring lengths. Wear-out mechanisms are assumed to have been eliminated. Costs Costs are driven by chip size. There are costly vacuum processes for metals and dielectrics and a strong need to simplify to meet this aggressive cost reduction plan. The trend is to borderless contacts and stacked vias.