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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 to be expected unless you do substrate extraction. The substrate will be treated as a single net, and so all bulk connections will be ideal. There is the option in QRC to do substrate extraction too, but this can generate a very large mesh of resistors so be warned - most of the time it is not necessary unless you really are trying to investigate some detailed coupling through the substrate.

    Regards,

    Andrew.

Reply

  • This is to be expected unless you do substrate extraction. The substrate will be treated as a single net, and so all bulk connections will be ideal. There is the option in QRC to do substrate extraction too, but this can generate a very large mesh of resistors so be warned - most of the time it is not necessary unless you really are trying to investigate some detailed coupling through the substrate.

    Regards,

    Andrew.

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