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 Can we add the FILLER cells after routing completed 

Last post Wed, Apr 4 2007 9:21 PM by archive. 3 replies.
Started by archive 04 Apr 2007 09:21 PM. Topic has 3 replies and 1870 views
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  • Wed, Apr 4 2007 9:21 PM

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    Can we add the FILLER cells after routing completed Reply

    Dear all,

    I am working on Place & Route flow,

    1. can any one suggest me when we should add FILLER cells ie after completing routing using nanoroute in cadence or after FIX wire in magma.

    2. what are the advantage and disadvantages, if FILLER cells are added before and after routing.

    Thanks & Regards,
    Prashant


    Originally posted in cdnusers.org by kulprashant05
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  • Wed, Apr 4 2007 9:46 PM

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    RE: Can we add the FILLER cells after routing completed Reply

    Hello Mastaru !! ,

    One should do FILLER cell addition before GDS strimout ( i.e after fixing DRC by P&R [after routing] )

    Please go through some basics CMOS design rules process to know more about it.

    Have you heard of postmaskECO ??

    for what type of FILLER cell you are talking about ??
    like i) subcon** ii) SPLIT** iii) CLIP** iv) CAP** ??

    Was there any difference in nanoroute and Magma Fix-cell options in your run ??

    Were you able to fix timing issues according to sign-off .


    Originally posted in cdnusers.org by mohanch007
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  • Fri, Apr 13 2007 2:06 AM

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    RE: Can we add the FILLER cells after routing completed Reply

    Hi Prashant,

    I prefer to add std filler cell after routing if possible. It is not possilbe if there are metal blockage in the filler cell except at the power rail. Most of the std fiiller cell I worked with does not have metal blockage that will affect detailed routing.

    However, it is better to add pad filler before rouitng as the router can use those space for routing if it is not fill by pad filler.

    Advantage of adding filler cell later is database size. The number of std filler can be several time of the other logic cell. The overhead is not small. I can't think of disadvantage, except that you have to be sure that the filler does not have blockage that will affect routing.

    Nowsaday all P&R tool can remove and add filler cells after detailed rouitng to fix timing or crosstalk. However, with nanometer process, adding of std filler cell can take awhile. So it is ready good if you can add the std filler cell just before performing full DRC.

    Regards,
    Eng Han


    Originally posted in cdnusers.org by EngHan
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  • Fri, Apr 13 2007 4:50 AM

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    RE: Can we add the FILLER cells after routing completed Reply

    Hi Eng Han

    Thanks for the explanation.

    Actually i had experiece that, my design was DRC cleaned after post route optimization and when i added Filler cells, then i found some number of DRC in the design. that is why i posted this question on the portal.

    Thanks & Regards,
    Prashant



    Originally posted in cdnusers.org by kulprashant05
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Started by archive at 04 Apr 2007 09:21 PM. Topic has 3 replies.