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From: elh@vu-vlsi.Villanova.EDU (Edward L. Hepler)
Newsgroups: comp.lsi
Subject: Re: Re: Problem reading GDS into Magic
Message-ID: <2220@vu-vlsi.Villanova.EDU>
Date: 24 Feb 89 02:32:14 GMT
References: <2214@vu-vlsi.Villanova.EDU> <7599@venera.isi.edu>
Organization: Villanova Univ. EE Dept.
Lines: 51

Shih-Lien Lu:

Thank you for responding.

I'm afraid I don't understand your comment. I have separate calma layers
for Contacts (CCA), Poly (CPG), and Metal1(CMF).  I assumed that magic
read this information into separate CIF structures and then combined them
in the way specified in the cifinput section of the tech file before writing
the appropriate magic layer.  In fact, doesn't the NMOS example in the 
Maintainer's Manual #2 (pg 18) do exactly this?

You say that:
>In order to get the contact you need to have all CCA,CPG and CMF
>on the same hierarchy. The way Magic and its tech file is set up,
>it will form the abstract layer "pc" only when all layers are
>presented.
>Possible solutions:
>	(1) flatten the geometry
>	(2) re-write the CIF in section of the tech to accomodate
>	    layers in different hierarchy. One way is to have no
>	    "abstract" layers but all Magic layer corresponds to
>	    a CIF layer. This is the simpliest method but you will
>	    not be able to extract correctly. (if you want to know
>	    why, I can explain to you on a seperate message)

I thought that I was doing it correctly.  After I read the GDS, I can
do a ":see no", then ":see con" (The extra layer I defined to hold CCA),
then ":see m1", then ":see poly" and verify that all the layers are
present where the contact should be.  Doesn't the cifinput rule:

    layer pc CCA
        and CPG
        and CMF

say to form a poly-metal contact on a magic layer where the CIF layers CCA,
CPG, and CMF coincide?   Did I misinterpret that magic makes a distinction
between CIF layers and its own layers?  I assumed that creating an extra
plane to hold the contacts would not hurt anything, especially since I
do not mention it in the drc or extract sections - it is only used when
reading GDS and has no rules or parasitics associated with it.  It allows
me to see where the CCA layer exists...

Please forgive me for being slow to understand...

BTW, Please post the result, as I haven't been able to get a response back
from my inquires to MOSIS via usenet mail to mosis@mosis.edu.

Thanks,

Ed Hepler
elh@vu-vlsi or hepler@cbmvax