i use hercules + star-RC to extract the layout netlist, but the ideal netlist generated by star-RC has some problems:

for example, i have one subckt AAA, it has three ports: IN OUT BIAS, but the translated ideal netlist has more ports as follows:

.subckt AAA IN OUT BIAS ln_N_27 ln_N_31 ln_N_33 ln_N_35
*************
.ends AAA

*******
XI2 IN1 OUT1 BIAS1 GNDA1 GNDA1 GNDA1 GNDA1 AAA

the additional ports ln_N_27, ln_N_31, ln_N_33, ln_N_35 don't exist in my layout at all, and all the additional ports connect to GNDA when instancing. such subckt which has additional ports(ln_N_*) is more than one. i want to know, why are the additional ports (ln_N_*) generated in netlist? is it caused by nettran? and how to solve this problem?


besides, can anyone use synopsys tools XA for simulation? in XA's BA(back annotation) flow, first, i use hercules + starrc to extract the ideal netlist (ideal.sp) and parasitic included netlist (top.spf), then i use BA flow for layout post-simulation. but i have a question here, in the ideal netlist, there is many additional nets (ln_N_*) which is not used in my layout at all as above mentioned. another aspect, the BA back annotation rate (back annotation without error) is not 100%, there are many nets not back annotated correctly, and these nets exist in resistor, for example, i have a big resistor (l=30u w=1u) which has three segments:
the ideal netlist is:
XRR1 OUT OUTN1 rpmpoly2t l=10u w=1u
XRR2 OUTN1 OUTN2 rpmpoly2t l=10u w=1u
XRR3 OUTN2 OUTN rpmpoly2t l=10u w=1u
but the spf netlist is:
XRR1 XI23/XRR1:A XI23/XRR1:B rpmpoly2t l=10u w=1u
XRR2 XI23/XRR2:A XI23/XRR2:B rpmpoly2t l=10u w=1u
XRR3 XI23/XRR3:A XI23/XRR3:B rpmpoly2t l=10u w=1u

and these nets (XI23/XRR1:A XI23/XRR1:B XI23/XRR2:A XI23/XRR2:B XI23/XRR3:A XI23/XRR3:B) cannot be correctly back annotated, what is the reason?
can anyone has the same experience before?

thanks all for reply in advance, thanks.

I've never had this problem before.  The "ln_" in some tools means something like "layout net" -- a net that exists because one of your schematic nets was split in the layout due to parasitic resistance.