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Hello <@U02HV6B4QLU> <@U016EM8L91B> I get DRC erro...
# ieee-sscs-dc-23
i
Hello @Farag Elsayed @Tim Edwards I get DRC errors when I read GDS file in magic although there are no errors in the mag file.
t
GDS reading and writing in magic are not symmetric operations and there is no guarantee that you can read back a GDS and recover the same layout you started with. That said, it's usually not the case with layouts created in magic. But I cannot tell what's going on from a screenshot.
i
The layout was created in magic. I am attaching the mag and GDS file.
PLL_TOP_MUX_7 (1).magPLL_v1 (1).gds
t
That layout appears to have surfaced some issue with the GDS read-in in the GF tech file. The GDS itself looks okay, though. If it passes the precheck using the klayout DRC deck, it should be okay. I just spot-checked some of the errors but they all seem to be repetitions of the same error which is coming from reading in the nwell tap contact from one (or some) of the subcells. But the contact and surrounding layers are fine in the GDS itself.
a
Hi @Tim Edwards @Mitch Bailey @Amro Tork @Farag Elsayed i have open this gds in klayout and got DRC as attached below, while as mentioned above there were no drc in magic, gds generated from magic had drc errors. I dig into on of error NW spacing and found out that klayout has spacing of nwell connected is 0.6 and unconnected is 1.4 while magic has only 0.6 for unconnected thus causing errors. Screenshot of rule deck is attached. Same magic/gds as ahmar mentioned is used.
I think maybe rule files are contradictory or maybe version of klayout i am using has some issue because resistor and cap also are getting error. Mim cap at the corner and edges is saying error of metal 5 overlap in klayout, however there was no such error in magic.
Resistor and cap are auto generated by magic file so spacing is decided by generator,either generator has error or rule deck between magic and klayout has some issues
In gds while writing/ reading it sadly fragmented one via into 3 parts while it can be seen that in magic it is in one piece. I think while writing gds there are some issues @Tim Edwards
a
@Atif Khan Could you please open an issue on https://github.com/efabless/globalfoundries-pdk-libs-gf180mcu_fd_pv ? Please make sure to mention in the Issue the version of Klayout you are using the Operating system and please provide the GDS that you using that has this violation.
f
@Atif Khan Please test your gds file using this version of DRC before opening that issue. https://github.com/efabless/globalfoundries-pdk-libs-gf180mcu_fd_pv/tree/main/klayout/drc
a
Okay i will test with then report this issue.
@Amro Tork gds file is attached above
PLL_v1.gds as attached in thread above
t
@Atif Khan: Magic doesn't have connectivity-based DRC rules so it cannot implement the unconnected net spacing rules.
Also there was no analog connections available on the GF open MPW runs, so the magic DRC decks and device generators were not exercised much outside of the standard cells and I/O library. Some updates were done over the summer. What version of open_pdks are you using?
a
I am using magic of probably 8.3.43something
I have updated two three weeks ago
t
I didn't ask about the version of magic, I asked about the version of open_pdks (i.e., the version of the GF tech file).
a
I don’t have tool access right now but i had gf tech file update 20 days ago version.
We have implemented whole design or i would say whole pakistan chip on magic now we are facing issue while extracting gds, i tried to check for error either it is magic reading or writing gds error. When i opened on klayout the whole new lot of issues welcomed us.
I have taken this from one of my teammate he has this version install, he is facing same issue i have upgraded one of october
t
The top two (Oct. 24 and Oct. 27) should have up-to-date tech files for GF. There were a lot of updates to the GF tech file and device generators for magic since the one you show highlighted in your screenshot (August 27).
a
I will update this and check whether this resolve my issue or not.
@Tim Edwards still issue not resolved i have waived off connectivity rules but still there are many other error we are getting
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