Layout off-grid problem

• Nov 11, 2007

• #1

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tia_design

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Hi,

We used Cadence Silicon Ensemble to do Place and Layout for our digital block. Now we found some blocks have off-grid problem. Worse thing is that our SE license is expired. We only have Virtuso Layout and Virtuso XL license active now. So how to solve this off grid problem? Re-layout it?? Thanks for your comments.

 

• Nov 12, 2007

• #2

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bjic

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hi,
You can settle it in virtuoso layout editor with skill.
But i'm sorroy i don't know how to do.
remit to programmer in your Depart.

Best regards.

Added after 21 seconds:

hi,
You can settle it in virtuoso layout editor with skill.
But i'm sorroy i don't know how to do.
remit to programmer in your Depart.

Best regards.

 

• Nov 12, 2007

• #3

D

dabing

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You can use the verification tool, and run the command file. And check the off-grid.
About the detail ,you can ask analog layout engineer.

 

• Nov 12, 2007

• #4

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tia_design

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Thanks for you reply. Layout Engineer also doesn't know how to solve this problem

 

• Dec 18, 2007

• #5

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rimser9

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I really dont understand the seriousness of this problem, but when there are offgrids when drawing a 45 degree metal I usually convert it to polygon (select it) and then type grid 0.01
or u can type grid [suitable grid supported]

Added after 37 seconds:

I mean type in CIW

 

• Dec 19, 2007

• #6

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layout_designer

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here are a few suggestions:

- make sure all ur blocks are alighed to origin if that is already done

-check individual cells in virtuoso for off-grid.

 

• Dec 19, 2007

• #7

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ajaytronic

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I think you can do it by importing the gds into magic tools or other tools which support 0.01 grid only. I did it once when I got same problem.
After saving export gds from magic, then again import it into virtuoso.
Hope it will work.

 

• Dec 20, 2007

• #8

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liu675

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use import in,and then modify the 0.001 to 0.01,that is OK

 

• Dec 20, 2007

• #9

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rimser9

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Magic option is good but I guess you have to convert the gds to ltl format before importing into magic.

 

• Dec 21, 2007

• #10

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ajaytronic

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Yes, We have to convert it into ltl format. I forgot to mention.
thanks rimser9

 

• Jan 9, 2008

• #11

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hionyeh

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here are suggestion:
You can use virtuoso streamin option snap to your target grid,it may be cause some gap at your database,you have to check DRC fix it.

 

• Jan 10, 2008

• #12

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sky&sea

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I think you can change the "Display option" in the Virtuso editor ,Be sure that the grid is same with that your PDK offered,

 

• Feb 13, 2008

• #13

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test_out

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sky&sea is rite

 

• Feb 17, 2008

• #14

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piao

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check your foundry layout grid option, if it is smaller than the grid you are using, you can change the grid option as same as the foundry option. then the problem will be gone.


when you draw layout, you are using the right grid option, then you can use some layout tool to adjust the origin of the layout to solve it.

the 3rd situation is the 45 degree situation, actually it is not a problem

if all above still do not solve your problem. maybe you need to redraw some of the layout.

good luck

 

• Feb 20, 2008

• #15

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mark_lhm

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You'd better do not to changer the grid size.
because the grid size have relation to the MASK building.
if you changed the grid size, maybe,the software tell you that the layout is OK! But the process engineer will tell you that the gds has problem! And they can't make the right MASK.(The grid size is decied by MASK process )
The answer to your question is make sure that eveything is on grid.
That is what I thought. Any questions contact me!

 

• Feb 21, 2008

• #16

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turtleden

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I have off-grid problem when using the edit->align function. And don't use 45 degrees.

 

• Feb 22, 2008

• #17

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mark_lhm

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turtleden said:

I have off-grid problem when using the edit->align function. And don't use 45 degrees.

Click to expand...

That is a good suggestion.
And if you have to use 45 degrees. You'd better make sure that the every grid point which is by passed is on the grid! because, most off-grid problem is cause by un 0 degress.