Hi, I’ve checked DRC for the 2KB RAM but got a lot of errors. Are they real errors or am I missing somethings?

The SRAM is checked using core DRC rules that Magic has not yet supported. Therefore, to bypass DRC violation, you need to load its abstract view before running DRC.

@Hieu Bui sorry I still don’t understand why we check DRC for the abstract view only to bypass the errors? From the physical layout (gds) there’re errors and eventually you need to run full DRC check for your entire design?

As explained by Prof. @Matthew Guthaus, the SRAMs are checked using DRC rules that are not currently supported by Magic. Openlane uses Magic for DRC check, therefore, you will experience a ton of violations. The SRAMs actually have clean DRC checks which was run by Prof. @Matthew Guthaus. You can just ignore the violations related to the SRAM because Magic does not support it.

I think we only have a drc rule set for any particular process from the foundry, and it’s independent with the tools (I’m using klayout in this case)?

Yes, but you need someone to implement these design rules into the tools such as Magic or Klayout. I believe the DRC rules in Magic and Klayout are just a subset which works and is enough for many designs. SRAM might be different.

I’m not sure but for some basic rules like spacing between metals, it always must be respected? For the particular showing error, I just wonder if is there any missing layer which covers the gap?

Prof @Matthew Guthaus can give you more infos. I guess it is just different from those already have in Magic and Klayout.

These are exceptions allowed by Skywater...

@Matthew Guthaus Thank you very much for your work. I will check it out :).

@Matthew Guthaus @Hieu Bui Thanks for the info