The mocmos shipped with Electric-9.05 has layers usable as TAP, active n++
in nwell, or p++ in pwell:
P-Active
N-Active
P-Active-Well
by usable, I mean going as far as DRC/LVS clean on a small simple cell with
few nmos, pmos, and both types of well TAP properly tied off.
None of these actives have a Well function:
<layer name="N-Active" fun="DIFFN">
<layer name="P-Active" fun="DIFFP">
<layer name="P-Active-Well" fun="DIFFP">
<layer name="N-Well" fun="WELLN">
<layer name="P-Well" fun="WELLP">
It so appears the mocmos shipped with Electric does not satisfy following
two rules from the manual, on Layer Function, page 245:
-quote
Two rules apply here:
1. There must be a separate diffusion layer for the p++ or n++ used as a
contact in a P−well or N−well, respectively; it cannot be the same layer
that is used for diffusions in active devices.
2. A p++ or n++ layer that is used to make a contact in a well of the same
semiconductor type (for example p++ in a P−well) must not be defined with
the layer function Diffusion; it must be declared as "Well". In the well
contact shown below, both the p++ layer and the P−well layer will be
defined with the layer function "Well, P−type".
-quote-end
(The P-Active-Well is unique/separate, but in my test need not be used,
P-Active works as TAP in P-Well; and all of the three, usable as TAP have
the function Diffusion. And there is no unique/separate n++ layer for use
in N-Well).
The question: Is the manual just old in this regard? If these rules are
still real, where in a flow would I see a problem if the rules are not
followed? Is it only necessary iff LVS-ing the mos with a 4th body
terminal, or would break spice netlisting for example?
Thank you.
-rb
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