Stats

  • Locked Locked
  • Replies 11
  • Subscribers 92
  • Views 21764
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

NanoRoute: DRC / LVS issues

kulprashant

Hi,

I have completed the routing using Nanoroute and the in the summary report, there are no LVS violation and few DRC violation(~50).

I saved the design and then from GUI, i check the DRC with all option (command : verifyGeometry with default option), then i was shocked by looking towards results, there thousand of violations and lot of process antenna violation(~100).

1, how it is possible? nanoroute has not dumped correct report or is thier any other issues?

2. In DRC, i have checked, there are similar violation (almost all are same) and the DRC errors are spacing violation with same net?

                                 exa: spacing vioaltion : metal: M3  actual =0.5   min =0.7

what is meaning of this and how to solve this type of issue (same type of violation with M2 & M1).

3. I found some max transition and max fanout violation, how to solve these violation at this stage? (because solving these vioaltion nothing but adding or sizing the buffers at placement level, it means  i have to do once again CTS and routing ) or any other method to solve or ecos??

Thanks & Regards,

Kul   

Parents

  • Hi Kul,

    I'm glad you got some of your issues resolved! For the remaining antenna violations, try adding an antenna cell by hand. Since you only have 2 left, it shouldn't be too bad. You may first want to run your signoff DRC/Antenna deck though - the results can sometimes be different than the output of Verify Antenna. The signoff check may show that those last two violations aren't real antennas, or it may show that you have a few more.  

     Your flow for fixing holds/setups sounds pretty typical, except that we normally let FE do the first round of hold fixing. But it is normal for hold fixing to break some setups/DRVs, then you go back and fix those, check holds again to make sure those are still good, etc. You may go back and forth like this a couple of times until things settle down. This isn't really an ECO flow - when we talk about an ECO, it usually means a functional netlist change. What you are going through is timing optimization. I would try to figure out why FE is adding so many buffers when you first try to fix holds. If you can get to the root of that issue, you would save yourself a lot of time doing hand-fixes. But if you have something scripted up, it may not be that big a time-hit.

     - Kari

Reply

  • Hi Kul,

    I'm glad you got some of your issues resolved! For the remaining antenna violations, try adding an antenna cell by hand. Since you only have 2 left, it shouldn't be too bad. You may first want to run your signoff DRC/Antenna deck though - the results can sometimes be different than the output of Verify Antenna. The signoff check may show that those last two violations aren't real antennas, or it may show that you have a few more.  

     Your flow for fixing holds/setups sounds pretty typical, except that we normally let FE do the first round of hold fixing. But it is normal for hold fixing to break some setups/DRVs, then you go back and fix those, check holds again to make sure those are still good, etc. You may go back and forth like this a couple of times until things settle down. This isn't really an ECO flow - when we talk about an ECO, it usually means a functional netlist change. What you are going through is timing optimization. I would try to figure out why FE is adding so many buffers when you first try to fix holds. If you can get to the root of that issue, you would save yourself a lot of time doing hand-fixes. But if you have something scripted up, it may not be that big a time-hit.

     - Kari

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.