|
|
|
How to remove Gaurd rings in SBC18 process of Jazz - RF Cafe Forums
|
ashishbondia
Post subject: How to remove Gaurd rings in SBC18 process
of Jazz Posted: Thu Sep 28, 2006 6:37 am
Captain
Joined: Wed Aug 16, 2006 8:20 am
Posts: 23
Location: India
Hi!
I am trying to make a layout using Jazz SBC18 Process. I realized
a BJT with multiplicity=10. Now when I am trying to generate a layout
for the device, all 10 devices are sorrounded by gaurd rings. In order
to connect these devices I have to remove the guard rings. But I don't
find any way to do it. Can you help me with this
_________________
Ashish Bondia,
Design Engineer- RF
Top
Stephen
Post subject: Posted: Thu Sep 28, 2006 1:20 pm
Captain
Joined: Wed Jun 21, 2006 8:33 pm
Posts: 21
Location: Queen
Creek, Arizona
What do you mean by you can't remove them:
Do you mean that you can not physically change the layouts in a
layout editor, because the guardrings are included with the BJT as part
of a P-Cell or macro cell? If this is the case, you can flatten the
instance of each BJT and then remove the guardring poly's. Note that
this will break any library links (models, symbols, etc).
Or
do you mean that design rules are not allowing you to remove the guardrings
because of a DRC violation? In this case it is not a good idea to remove
the guardings unless you have a buddy in the foundary process devlopment
team who can vouch for what your are trying to accomplish.
Beyond this:
My next question is how is it that the guardrings
are not allowing you to connect up the BJT's. Typically guardrings are
only M1, so connectivity should be asily accomplished with M2? If these
are RF BJT's, it may be that you do not want to remove the guardrings
as they may have been included in the modeling and to remove them from
the P-Cell will invalidate your model (or at least degrade the accuracy).
_________________
CMOS RF and Analog ESD Specialist!
www.srftechnologies.com
Top
ashishbondia
Post subject: Posted: Fri Sep 29, 2006
12:32 am
Captain
Joined: Wed Aug 16, 2006 8:20 am
Posts: 23
Location: India
Thank you for your comments.
I wanted
to remove the gaurd rings because I was tring to arrange the BJTs in
a fashion so that I could use Both M1 and M2 for connections. the Base
terminal of the BJT does not has M2. I also didn't want to use any M1
to M2 via.
While working with a different foundry I encountered
a similar situation, However there the foundry manual provided enough
informations on how to remove the rings and replace it with a larger
one when I have connected all the BJTs and FETs
_________________
Ashish Bondia,
Design Engineer- RF
Top
Stephen
Post subject: Posted: Fri Sep 29, 2006 1:29 am
Captain
Joined: Wed Jun 21, 2006 8:33 pm
Posts: 21
Location: Queen
Creek, Arizona
Sounds like your set then, and yes it is a common
practice to guardring the multiple legs/instances of a device, assuming
they are all connected, with one large guardring as opposed to every
leg individually.
Good luck.
-Stephen
_________________
CMOS RF and Analog ESD Specialist!
www.srftechnologies.com
Posted 11/12/2012
|
|
|
|
|
