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Other CAD Tools >> Physical Verification, Extraction and Analysis >> Rnwell Assura LVS issue
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Message started by Rwalker on Jul 1^st, 2009, 9:04pm

Title: Rnwell Assura LVS issue
Post by Rwalker on Jul 1^st, 2009, 9:04pm

I get funny LVS errors when using rnwell pcells from my pdk:

ntap connected to GROUND !
(some of my nwell resistors terminate at gnd)

floating nxwell is not allowed
(I see this for series segments of my R that are not the top/bottom segments)

I tried applying the HOTWL layer but still see these errors.

Title: Re: Rnwell Assura LVS issue
Post by Andrew Beckett on Jul 10^th, 2009, 9:06am

You're more likely to get a meaningful answer if you state what design kit or Assura Rules you're using. Without knowing that, the messages could mean anything...

Regards,

Andrew.

Title: Re: Rnwell Assura LVS issue
Post by rfeda on Nov 8^th, 2009, 2:36pm

The error message in your case seems to be an ERC error. The check "ntap connected to gnd" should normally be performed on any nwell that contains a p-mosfet" or an nwell forming an isolation ring of some sort. This check should be done to ensure no nwell/p-sub diode is forward biased.

The resistor nwell should be precluded from this check. You could solve this issue by examining the generation of the "nwell" layer used to perform the ERC check.

Modifying the generation of the nwell may stop these violations on the resistor nwell.

Hope this helps.