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Other CAD Tools >> Physical Verification, Extraction and Analysis >> resistors has wrong # of segments in extracted view
https://designers-guide.org/forum/YaBB.pl?num=1384244163

Message started by ywguo on Nov 12^th, 2013, 12:16am

Title: resistors has wrong # of segments in extracted view
Post by ywguo on Nov 12^th, 2013, 12:16am

Hi Guys,

A resistor in schematic view has 10 segments in series. In the extracted view, it becomes 10 resistor instances in series. I expect that each one has one segment. Unfortunately, each one has 10 segments now. So the resistance becomes 10 times of that in the schematic view.

The tool is Assura sub-version 4.1_USR3, IC 6.1.5.500.14.

One part of the spectre netlist of that extracted view is shown below.

Code:

u_rdiv\|R3_9__rcx (agnd_h \4\:\#7cu_rdiv\|avC34 \#7cu_rdiv\|avC33) \
rpposab_3t_ckt_pcell_0 m=1 segL=7.864e-06 segW=1e-06 mismod=1 \
flag_cc=0
...
subckt rpposab_3t_ckt_pcell_0 B MINUS PLUS
parameters segL=8u segW=1.5u mismod=1 flag_cc=1
R9 (n9 MINUS B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R8 (n8 n9 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R7 (n7 n8 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R6 (n6 n7 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R5 (n5 n6 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R4 (n4 n5 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R3 (n3 n4 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R2 (n2 n3 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R1 (n1 n2 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
R0 (PLUS n1 B) rpposab_3t_ckt l=segL w=segW mismod=mismod \
flag_cc=flag_cc
ends rpposab_3t_ckt_pcell_0
// End of subcircuit definition.

Any comments are appreciated.

Best Regards,
Yawei

Title: Re: resistors has wrong # of segments in extracted view
Post by boe on Nov 12^th, 2013, 12:55am

Yawei,
I'd suspect a bug in the PDK.
- B O E
PS: Do you use the tool version recommended by the FAB?

Title: Re: resistors has wrong # of segments in extracted view
Post by ywguo on Nov 12^th, 2013, 1:35am

Hi B O E,

That is PDK of SMIC 40 low leakage process. The PDK code is SPDK40LL_1125_1TM(2TM)_OA_CDS. PDK revision is V1.4. Released on 2012-10-11.

You are right. Assura is not listed as a design platform in its release note. :(

I should go to ask SMIC.

Best Regards,
Yawei

Title: Re: resistors has wrong # of segments in extracted view
Post by boe on Nov 13^th, 2013, 2:31am

Hi Yawei,
we have seen something like this with a different PDK. I just heard our FAB confirmed the bug.
- B O E

Title: Re: resistors has wrong # of segments in extracted view
Post by ywguo on Nov 15^th, 2013, 2:13am

Hi B O E,

What's your tool? I have a solution now.

Force segments=1 with the following command in extract.rul.

segments=calculateParameter(length-length+1)
attachParameter( segments, "segments", deviceLayer)

Best Regards,
Yawei

Title: Re: resistors has wrong # of segments in extracted view
Post by boe on Nov 15^th, 2013, 6:09am

Hi Yawei,
we use Assura 4.1, too. So, if I understand correctly, you patched the extract.rul file with these two lines to fix it?
Best regards,
- B O E

Title: Re: resistors has wrong # of segments in extracted view
Post by ywguo on Nov 17^th, 2013, 10:04pm

Hi B O E,

Yes, I patched the extract.rul file with those two lines.

My extraction tool is cadence Extraction QRC - 64-bit Parasitic Extractor - Version 12.1.0-s488. But I think that rule is valid for Assura 4.1, too.

Best Regards,
Yawei