what is better thing about metal length

[vesperon]

hi
in deep sub micron

what is the better one

1. short metal length
2. long metal length

in dsm, long metal(long net) increase the delay
so i think short metal is better than long metal
is it right?

if so, how can reduce the metal length in PnR? (encounter)

thank you

 

[shaiko]

Shorter length will be better (also true for PCB traces).
Less delay, less signal integrity issues - allows steeper slew rates and faster clocks.