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#sky130
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# sky130
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John Kustin

06/01/2021, 5:38 AM
What does error message dnwell.3 mean?
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6.3 min. spacing/notch of dnwellNotPhotoNotUHVI
and what's dnwellNotPhotoNotUHVI??
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Tim Edwards

06/01/2021, 12:56 PM
That means deep nwell not used within an ultra-high-voltage area (mask UHVI, used for 20V devices) or within a photodiode device. The spacing requirement between individual deep nwells is quite large.
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John Kustin

06/01/2021, 4:16 PM
If there's just one large area of deep nwell used within this area then there's no requirement for spacing, right? Assuming no other UHVI area is nearby.
Sorry to keep bothering, but I have a few more questions about DRC rules.
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"Deep N-well spacing < 6.3um (dnwell.3) "
"Deep N-well spacing to N-well < 4.5um (nwell.7) "
"N-well overlap of Deep N-well < 0.4um outside, 1.03um inside (nwell.5a, 7) "
What do these violations mean together? Do I need deep nwell to subsume the nwell area?
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Tim Edwards

06/01/2021, 4:30 PM
Deep nwell spacing to nwell only refers to nwells outside of the deep nwell area, not inside. The last rule means that there has to be a guard ring of nwell forming a complete ring around dnwell; this forms the "wall" that isolates the interior p-well region.
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John Kustin

06/01/2021, 4:58 PM
Now I'm really confused about a DRC violation that pops up in the precheck. I'll ask the question in #caravan