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VSR: How to avoid router to route over floating fill

MARTH0401

Hi,

I am trying to resolve an issue where router is routing a metal layer directly on top of a floating fill layer of the same layer. Are there any constraints to set to avoid this. This is causing a short and thus failing LVS.

example:

m2 fill layer exists in the layout and not from the router. After VSR run finishes, ports are being connect and in the process the m2 drawing from the router draws directly on top of the m2 fill. How do we prevent this?

thanks!

  • I just want to add that the m2 fill in the layout is just floating and not a port that needs any connections. I just need a way for the router to route m2 drawing someway around the m2 fill or if there are any other options to avoid the shorting behavior 

  • in reply to MARTH0401

    Hi,

    Apologies; I didn't find time to respond yesterday. Firstly; I wouldn't expect this to happen. A quick test and I find VSR avoids floating metal shapes. Some questions...

    1) Which router? I'm assuming its VSR within Virtuoso.

    2) How is the fill created? Is it just flat shapes (which is what you kind of imply)? Or in a placed fell cell? And if a cell are we talking down on level of hierarchy or possibly more?

    3) What layer is the fill on? Is it on the same layer as the routing (e.g. 'metal1 drawing') or the dedicated 'fill' purpose (e.g. 'metal1 fill')? N.B. I find gpdk045 does "short" over 'Metal1 fill'.

    4) Which version of Virtuoso are you using?

    5) Which foundry pdk are you using?

  • in reply to RobMan

    Hi, 

    1.) I am using VSR (Virtuoso Space Based Router)

    2.) The fill shapes are seen only in the sub-levels of the layout depth and not at the toplevel. 

    3.) The fill is on m2 layer. It is the same layer as the routing which is m2 drawing.The m2 fill exists inside the hierarchy and the VSR router is using m2 drawing to route pins in the layout right on top of the m2 fill in the sublevel that is floating, which leads to a short.

    4.) I am using Virtuoso IC 23.1

    5.) I am unable to provide this information on a public forum 

  • in reply to MARTH0401

    I cannot repeat this behaviour. Please contact customer support.

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