[SOLVED] Units mismatch in technology file (.tf) and the reference library file (.db)

[bhaismachine]

I am using Synopsys 90nm standard cell reference libraries to generate verilog netlist (dc_shell) and then to generate layout (icc_shell) using this netlist.

When I read the netlist into IC compiler, it gives me a warning:

"Warning: Unit conflict found: Milkyway technology file capacitance unit is pF; main library capacitance unit is fF. (IFS-007)"
"Warning: Unit conflict found: Milkyway technology file resistance unit is kOhm; main library resistance unit is MOhm. (IFS-007)"

Eventually IC compiler scripts completes all the steps, but it gives me warning about this unit mismatch at several other places. I am wondering if this would lead to incorrect values of parasitic capacitances and resistances when I extract them using the layout. I need to extract these values for SPICE simulations eventually.

I believe I can adjust the units by either editing the .tf file, or by editing the .lib file and re-create a new .db file. The problem is that I don't know the correct format of these files so I don't know how to really edit these files and fix these units.

So the question is:

Does someone know how to change units of these libraries without breaking anything else? I think Synopsys isn't going to be very helpful in this situation since they don't really provide much support for this package and they provide these 90nm libraries for university research/educational purposes. Thanks !

Any help or suggestion will be very appreciated, even if it's not a complete solution. This is also my first time posting on this forum.

 

[anilineda]

 The problem is that I don't know the correct format of these files so I don't know how to really edit these files and fix these units.

you can explore the chapter 3 (standard cell library) from the book: (STATIC TIMING ANALYSIS FOR NANAOMETER DESIGNS by jayaram bhaskar) to know much about the format of the files and eventually the syntax.

Regards,
Anil

 

[Prashanthanilm]

For extraction, you use the parasitic models provided from the Foundry (Synopys - nxtGrd/ITF/TluPlus) .
Since, your LIB (db) file is with fF. This is golden to start with.

Tech File (in most case) won't have parasitic information required for extraction. You probably use the foundry parasitic models.

This warning can be ignored I believe.

This is my understanding.