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As a designer, the L (direction of current flow) is fixed

by poly etch and the fin thickness (height) by poly dep.

Not for you to touch.

If lfin is the width (across current flow) then that may be

for you, provided that the foundry did not put fixed-segment

rules on you. You'd have to read up on that, my knowledge

stops at GF 12/14. nfin is surely your call, have seen maybe

100 fins in some big devices, again check specific

foundry * flow and whether you are bound by fixed

underlayers in some semicustom environment.

Really you should just go look at commercial PDKs' PCells,

their properties are all you can touch without some

negotiation with the foundry about waivers and custom flow

(which leads to custom requalification, whigh leads to your

management saying "are you off your meds, again? ...)"

The designer is more and more constrained as tools become

less and less certain to "hold the line (width)". We're already

being made responsible for device drift (used to be a reliability

criterion), reduced service life (hours per day, shirt pocket temp

range "use model"), now you get to pick either X or Y dimension

(but not both_ for critical features and orientation, what's left

besides "too many rules, let AI do it and we'll let you know if it

fails so you can try again, still knowing nothing".

At least analog still has some runway before going completely

to sh!t. Because fins svck for analog and everybody knows it.