what will happen if we route from M9 to M1 (wider width to lower width) instead of M1

[rameshiloveu]

what will happen if we route from M9 to M1 (wider width to lower width) instead of M1 to M9 ?

 

[dick_freebird]

This all depends on the signal attributes of interest.

Typically upper levels are thicker and may have looser
layout rules (esp. in RF and power oriented processes)
so routing on M9 will cost you density.

Routing on M1 will cost you more series resistance,
capacitance to substrate, and impose a lower max
current density (metallurgy being equal, which is a
fair but not sure bet).

In either case you'll pick up 8 vias' worth of series
R which in a tungsten plug process can be more
than the intralayer resistance. Depending on the
distance of course.

 

[rameshiloveu]

Thanks a lot dick