Save All Nets Within A Specified Cell in Spectre

First create save.scs and add the following line:

save I0.I305.*

Then, set save option as

saveOptions options save=selected

There are other variations in "save" statement, e.g.: the following example saves nets within all instances of subcircuit "osc" (use subckt)

save * subckt=osc

and the following example saves all nets up to level 2 (use depth)

save * depth=2