Antenna Error in Calibre DRC but Passed antenna check in Encounter

Hello,

When you have generated your lef macro with Abstract generator did you extract teh antenna ?

If the antenna information are not part of your abstracts the router could not check and calculate the antenna ratio and fix them.

Thanks,

Alex

Hi Alex,

Thanks for the quick reply, actually i am able to put the antenna cell into my design during the place and route. and it is able to fix the antenna error in encounter as well, but the problem is that, when i stream out the design to do the calibre DRC check in virtuoso, hundreds of antenna error is reported, FYI following is the example of the macro lef i created,

 MACRO DL_XOR_NXOR2X1
  CLASS CORE ;
  ORIGIN 0 0 ;
  FOREIGN DL_XOR_NXOR2X1 0 0 ;
  SIZE 8 BY 4 ;
  SYMMETRY X Y ;
  SITE core ;
  PIN gnd!
    DIRECTION INOUT ;
    USE GROUND ;
    SHAPE ABUTMENT ;
    PORT
      LAYER M1 ;
        RECT 0.76 0 1.04 1.19 ;
        RECT 6.96 0 7.24 1.25 ;
        RECT 0 0 8 0.28 ;
    END
  END gnd!
  PIN vdd!
    DIRECTION INOUT ;
    USE POWER ;
    SHAPE ABUTMENT ;
    PORT
      LAYER M1 ;
        RECT 0.76 2.8 1.04 4 ;
        RECT 3.15 2.81 3.43 4 ;
        RECT 4.09 2.73 4.37 4 ;
        RECT 6.01 2.8 6.29 4 ;
        RECT 6.96 2.79 7.24 4 ;
        RECT 0 3.72 8 4 ;
    END
  END vdd!
  PIN nB
    DIRECTION INPUT ;
    USE SIGNAL ;
    ANTENNAMODEL OXIDE1 ;
      ANTENNAGATEAREA 0.2016 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 1.98 1.69 2.28 1.99 ;
    END
  END nB
  PIN Q
    DIRECTION OUTPUT ;
    USE SIGNAL ;
    ANTENNADIFFAREA 0.2688 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 7.44 0.97 7.88 1.25 ;
        RECT 7.72 0.97 7.88 3.03 ;
        RECT 7.44 2.73 7.88 3.03 ;
    END
  END Q
  PIN A
    DIRECTION INPUT ;
    USE SIGNAL ;
    ANTENNAMODEL OXIDE1 ;
      ANTENNAGATEAREA 0.2016 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 3.82 1.69 4.31 1.99 ;
    END
  END A
  PIN nA
    DIRECTION INPUT ;
    USE SIGNAL ;
    ANTENNAMODEL OXIDE1 ;
      ANTENNAGATEAREA 0.2016 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 1.36 3.24 1.66 3.54 ;
    END
  END nA
  PIN REQ
    DIRECTION OUTPUT ;
    USE SIGNAL ;
    ANTENNADIFFAREA 0 LAYER M1 ;
    ANTENNAMODEL OXIDE1 ;
      ANTENNAGATEAREA 0.2016 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 1.15 2.01 1.45 2.31 ;
        RECT 6.64 2.01 6.94 2.31 ;
        RECT 1.15 2.15 6.94 2.31 ;
    END
  END REQ
  PIN B
    DIRECTION INPUT ;
    USE SIGNAL ;
    ANTENNAMODEL OXIDE1 ;
      ANTENNAGATEAREA 0.2016 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 2.86 1.69 3.16 1.99 ;
        RECT 3.32 1.35 3.48 1.85 ;
        RECT 2.86 1.69 3.48 1.85 ;
        RECT 3.32 1.35 4.69 1.51 ;
        RECT 4.53 1.35 4.69 1.86 ;
        RECT 4.53 1.7 5.16 1.86 ;
        RECT 4.88 1.7 5.16 1.99 ;
    END
  END B
  PIN nQ
    DIRECTION OUTPUT ;
    USE SIGNAL ;
    ANTENNADIFFAREA 0.2688 LAYER M1 ;
    PORT
      LAYER M1 ;
        RECT 0.12 0.97 0.28 3.03 ;
        RECT 0.12 0.97 0.56 1.25 ;
        RECT 0.12 2.73 0.56 3.03 ;
    END
  END nQ
  OBS
    LAYER M1 ;
      RECT 2.67 0.97 2.95 1.25 ;
      RECT 0.77 1.35 2.83 1.51 ;
      RECT 2.67 0.97 2.83 1.51 ;
      RECT 0.63 1.46 0.93 1.76 ;
      RECT 0.77 1.35 0.93 2.64 ;
      RECT 0.77 2.48 2.35 2.64 ;
      RECT 2.19 2.48 2.35 3.03 ;
      RECT 1.24 2.48 1.4 3.03 ;
      RECT 1.24 2.8 1.52 3.03 ;
      RECT 2.19 2.74 2.47 3.03 ;
      RECT 1.83 0.65 3.63 0.81 ;
      RECT 3.47 0.65 3.63 1.19 ;
      RECT 1.83 0.65 1.99 1.19 ;
      RECT 1.31 0.97 1.99 1.19 ;
      RECT 3.47 0.97 3.75 1.19 ;
      RECT 2.79 2.47 3.79 2.63 ;
      RECT 3.63 2.47 3.79 3.03 ;
      RECT 1.7 2.8 1.98 3.03 ;
      RECT 2.67 2.75 2.95 3.03 ;
      RECT 3.63 2.73 3.91 3.03 ;
      RECT 1.82 2.8 1.98 3.36 ;
      RECT 2.79 2.47 2.95 3.36 ;
      RECT 1.82 3.2 2.95 3.36 ;
      RECT 4.57 2.73 4.85 3.03 ;
      RECT 5.53 2.8 5.81 3.03 ;
      RECT 4.69 2.73 4.85 3.47 ;
      RECT 5.53 2.8 5.69 3.47 ;
      RECT 4.69 3.31 5.69 3.47 ;
      RECT 4.37 0.65 6.17 0.81 ;
      RECT 6.01 0.65 6.17 1.19 ;
      RECT 4.37 0.65 4.53 1.19 ;
      RECT 4.25 0.97 4.53 1.19 ;
      RECT 6.01 0.97 6.29 1.19 ;
      RECT 5.53 0.97 5.81 1.19 ;
      RECT 6.47 0.97 6.75 1.25 ;
      RECT 5.65 0.97 5.81 1.51 ;
      RECT 6.47 0.97 6.63 1.51 ;
      RECT 5.65 1.35 6.63 1.51 ;
      RECT 4.73 0.97 5.12 1.19 ;
      RECT 4.96 0.97 5.12 1.54 ;
      RECT 4.96 1.38 5.49 1.54 ;
      RECT 5.33 1.38 5.49 1.83 ;
      RECT 5.33 1.67 7.26 1.83 ;
      RECT 7.1 2.11 7.4 2.41 ;
      RECT 7.1 1.67 7.26 2.63 ;
      RECT 5.17 2.47 7.26 2.63 ;
      RECT 5.17 2.47 5.33 3.03 ;
      RECT 5.05 2.8 5.33 3.03 ;
      RECT 6.49 2.47 6.77 3.03 ;
  END
END DL_XOR_NXOR2X1

I wonder whether this discrepancy is caused by the tech .lef where i use it directly as provided by the foundry. Thanks! Regards, MF

Hi,

As you mentionned it could be duee to a mismatch between Virtuoso techfile and calibre techfile.

Thanks,

Alex

Hi Alex,

I think that is the case, i saw some of the similar error in google and mentioned something about "AntennaDiffSideAreaRatio PWL " in the tech lef need to be change, but i am not sure how to do that and i can't even find it in my tech lef.

I think most important is i need to know why are there discrepancy between calibre and encounter antenna check at the first place.

Thanks so much for the reply.

Regards, MF

Hi MF

My guess is that this might be due to your Encounter settings. It would be best if you can contact your local Cadence support and submit a testcase so that they can assist you in debugging this. If you would like to request for more help from our forums, perhaps you might want to post the same question in the digital implementation forum. Similar questions have been asked in that forum. When submitting the post, please indicate the version of Encounter which you are using and the relevant settings related to antenna fixing.

linux>encounter -version

Best regards
Quek

I'll move this question to the Digital Implementation Forum, so the complete history is preserved.

Regards,

Andrew.

Hi MF

Your issue has already been highlighted to our office. My colleague supporting Encounter will go onsite to review this issue. I believe that she has already sent you an email for the earliest possible date of the onsite. We will do our best to resolve this as fast as possible. Sorry about the delays.

Best regards
Quek

Hi Quek,

It's great to hear from your side, at least now i have some hope to settle the case before the tape-out. thanks again for your continuous support.

Thanks again!

 MF