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  3. Specify the metal Layers in SOC encounter

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Specify the metal Layers in SOC encounter

amythpai
amythpai over 12 years ago

Hello,

 I am a newbie at placement and routing. I want the routing to be done using only metal 3,4 and 5 ( basically other than metal 1 and 2).

Can anyone please advise me as to where I have to mention this and the command used to get routing metal layers set? 

 

Any help in this regard is appreciated!

Thank you 

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  • Kari
    Kari over 12 years ago

    setNanoRouteMode -routeBottomRoutingLayer 3

    setNanoRouteMode -routeTopRoutingLayer 5

     However, this could make routing to the pins more difficult. 

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  • amythpai
    amythpai over 12 years ago
    Thank you for your Quick reply. Actually I have tried this but it resulted in a lot of DRC violations. My probelm is that I had initially routed using default option for routing layers. I ran the verify geometry command and it didnot result in any violations. But when I exported the gds file in to virtuoso and ran the DRC check it resulted in 15k errors. I found that many of the errors were not detected by the SOC encounters Verify Gemetry option were now getting detected by the Virtuoso DRC which looks strange. Then I tried to route using metal layers 3 to 5 only but it resulted in DRC violations at the SOC encounter stage itself. Will changing the cell utilisation or the size of the floorplan make a difference. If not can you suggest any other method? Thank you for your help!
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  • Kari
    Kari over 12 years ago
    there's definitely something strange going on here, since verifyGeometry should see most, if not all, any problems that DRC would catch. do you have snapshots of one of the errors in both virtuoso (flagged by DRC) and EDI ? When you say "Virtuoso DRC", what DRC tool is it actually? Assura/PVS/etc.? what process/foundry is it? we need some more specific information before suggesting what to try next.
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  • amythpai
    amythpai over 12 years ago
    DRC tool used : Calibre
    Process: Cmos065

    We have certains cells which are custom defined at the layout level and we have written the LEF file on our own, I think this may be the route cause of the problem! In the Lef file we have individually described all the metal pins and theobstructions, but the routing produces DRC errors( valid errors) which are not detected by SOC encounter.
    • DRC errors.png
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  • Kari
    Kari over 12 years ago
    so this might be a case of the LEF not really matching the GDS. for the picture, I meant of the actual geometry of one of the violations in your cells (from virtuoso with the calibre marker), compared to the same coordinates in EDI. then we can see if it's a lef/gds mismatch.
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  • amythpai
    amythpai over 12 years ago
    hello... Sorry for the delay. I wasnt in town. Actually I think I know what the problem might be. It may just be the case of wrong units or grids . I was just comparing the two i.e the SOC encounter and the layout from virtuoso and I found that the two have a difference in spacing. For example in the SOC encounter the two metal 1 layers have sufficient distance to meet the design rules but in virtuoso it is showing lesser distance and hence identifying it as an error.( minimum distance rule) I am streaming out the gds file from the SOC encounter in 2000 units. Should I specify or check any option ( like snap to grid option) while I am streaming in the gds file? Please advice me if this actually is the problem and how I can fix this Thanks a lot for all the help
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  • Kari
    Kari over 12 years ago
    Try streaming out with units 1000 - then see if the measurements in EDI and Virtuoso match.
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  • amythpai
    amythpai over 12 years ago
    Hello... I tried it yesterday.. But there seems to be no change in the number of errors!!
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