( ESNUG 398 Item 10 ) -------------------------------------------- [07/31/02]
Subject: ( ESNUG 396 #5 ) PhysOpt 2.5-D Extraction Isn't Exactly Here Yet
> What's the deal with the new 2.5 D extraction in PhysOpt? Specifically,
> will it eliminate the RC correlation step in PhysOpt?
>
> I was told by the PhysOpt R&D manager at DAC that this new extraction
> engine should eliminate the need for correlation. That we should try it
> for ourselves and if the R and C factors are not close to 1, we should
> file a bug report. However, our scaling factors turn out exactly the same
> as their 1-D extraction and nowhere close to 1.
>
> I can't get a straight answer from Synsopys. Any ideas?
>
> - Mahsa Vahidi
> Mindspeed Technologies San Diego CA
From: [ Trojan Man ]
John,
The new 2.5 D PhysOpt extractor is untested alpha code based on the Synopsys
proprietary .db and .pdb databases. It is green code. This is why the
PhysOpt R&D manager wants users to file bugs against it. Avanti Star-RC
gives Synopsys a debugged 2.5 D extractor, but it is based on the Avanti
proprietary Milkyway database. PhysOpt won't have viable 2.5 D extraction
until PhysOpt is ported into Milkway. If you publish this, I am anon.
- [ Trojan Man ]
---- ---- ---- ---- ---- ---- ----
From: Mahsa Vahidi <mahsa@mindspeed.com>
Hi John,
I finally got the answer to my question from a Synopsys AE. The PhysOpt
2.5-D extraction engine does not need RC correlation. Actually, there is
no way to even obtain correlation numbers in the current version of PhysOpt.
The numbers which were printed out by estimate_rc (and were confusing me)
are there for backward compatibility and are comparing the actual DSPF to
the numbers in the library. Basically, these numbers should be ignored.
The curve that is printed out by the compare_rc command (which actually
should be called compare_c since it doesn't compare resistance) is the
actual correlation between the 2.5-D extraction engine and your DSPF.
If the curve doesn't correlate well, you have to back-annotate post-route
data and run physopt -incr -post_route to fix any violations if they exist.
- Mahsa Vahidi
Mindpseed Technologies San Diego CA
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