Stats

  • Locked Locked
  • Replies 11
  • Subscribers 126
  • Views 18008
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Problem with MOS Bulk Routing Parasitic Resistance Extraction

Stepan

Hi,

During the Spectre netlist generation process, I have found out that the Assura QRC extractor includes the parasitic resistances of the MOS transistor bulk routing in the extraction view:

rg58 (vdda \5\:vdda) resistor r=24.5376 c=0

But, it skips connecting this parasitic resistor to the bulk of the transistor:

M10 (\3\:vout \5\:nclk \2\:vin vdda) p_lv_18_mm w=1.92e-06 l=2.4e-07 ad=2.224e-13 as=2.224e-13 pd=2.0u ps=2.0u m=(1)*(1)

From the line above, you can see that it circumvents the parasitic resistor and connects the bulk directly to the polarization net vdda (NOT \5\:vdda)

As a result, the simulation netlist generated from this extracted view is also incorrect.

 

I have tried two different technologies with two different design kits and both have the same issue. Two kits are:

1. Virtuoso Design Environment version IC6.1.3.500.13 with Cadence Extraction QRC - Parasitic Extractor - Version 8.1.4-p002.

2. Virtuoso Design Environment version IC6.1.5-64b.500.132 with Cadence Extraction QRC - Parasitic Extractor - Version 11.1.2-p106.


Is there any way to fix this problem? Can it be done by modifying the configuration script or updating the kit?

Thanks,

Stepan.

Parents
  • This is apparently a recurring problem with QRC. As per Andrew's suggestion I had created local areas of well/substrate around devices where I wanted the bulk connection to use the local substrate/well taps so I get the metal routing resistance included in an extract. I found for QRC 14.20.000 there were obvious bugs as some devices were using the same sub-node of R extracted vdd/vss networks. Switching to QRC 10.13.065 the problem went away. Of course there may be other less obvious bugs in the older release...
Reply
  • This is apparently a recurring problem with QRC. As per Andrew's suggestion I had created local areas of well/substrate around devices where I wanted the bulk connection to use the local substrate/well taps so I get the metal routing resistance included in an extract. I found for QRC 14.20.000 there were obvious bugs as some devices were using the same sub-node of R extracted vdd/vss networks. Switching to QRC 10.13.065 the problem went away. Of course there may be other less obvious bugs in the older release...
Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.