encounter Digital Implementation system tool - layout issue

 Hi Hon,

EDI is not meant for viewing the full layouts of std cells, macros, IOs, etc. The .lib files contain timing and other logical info, and the .lef files contain the abstracted physical info. To see the full layout of your design, you will need to bring it into Virtuoso, as you have already guessed. There are a couple of ways to do that. You can use OA or you can stream gds out of EDI and into Virtuoso. I think you can also bring a DEF from EDI into virtuoso, but I don't think that's a very common method and there is other setup involved. I don't have any experience with OA, and it has been many years since I've imported DEF, so I will explain the gds method here.

In EDI, there is a streamOut command. You provide a map file that maps the layer names used in EDI to the gds stream layer numbers for the process. You can either stream out just references to the cells (the default) or use the -merge option to include the std cell/macro/etc. gds files. (The gds files may exists somewhere in your ARM folder). If you use the -merge option, then you should be able to just stream the EDI gds into Virtuoso and then see your whole design. If you don't use merge, then you must already have DFII libraries of your std cells or other design pieces that the EDI gds can reference when you stream it in. Sometimes a design kit or library will come with the DFII libraries already, but sometimes only the gds is given, so you create these DFII libraries yourself if you want to. It sounds like they weren't included for you, so I would look for the std cell gds and try the -merge option of EDI's streamOut command as a starting point.

- Kari

Hi Kari,

 Thanks for your reply. It really give me more insight into the problem I facing right now.

 The problem now is that currently I am using IBM 130nm cmrf8sf process in a university, and I do not have the standard cell GDS file. Is that possible to import layout into Virtuoso using other method such as Open Acess? and what type of files are required if I import layout using Open Acess?

 Thank you.

hon cheong

 Hi,

It's possible that the library vendor does not provide a complete design kit for the university setting. Can you contact the library vendor and ask about this? 

As I said, I don't have any experience with OA, so I'm not sure what files to tell you to look for. Check the Cadence documentation for something regarding Design Import with OA. Maybe someone with some OA experience can chime in here and help?

 - Kari

Hi Kari,

 Because we get the process file from IBM through MOSIS, and we are confirmed that we are not provided the standard cell GDS file. I guess when I am about to tape out, the vendor will merge the GDS file for me.

Is there any other alternative to import layout from encounter into virtuoso without standard cell GDS file? I need to do DRC and parasitic extraction in Virtuoso. Is that possible to use DEF format without the standard cell GDS file? Please advice .

Thank You.

Regards,

hon cheong

 If you want the true layout of the std cells, you need either the GDS or an already-created DFII library. But if you want to see the same data you see in Encounter (abstracts vs full layouts) in Virtuoso, you can do that. You would read the std cell LEF into Virtuoso and you'll have abstract views (instead of layout views) in the library. Then you can read in the DEF and it should pick up the std cell abstracts. Consult the Virtuoso documentation for more information about reading in LEF and DEF.

But you can't run a true DRC (and LVS) unless you have the full layout. So I'm assuming that if MOSIS is merging your final GDS, then they will also have to run signoff DRC and LVS and report back to you any errors they find. This loop can be time-consuming. Get the data as clean as you can in Encounter by running Verify Connectivity, Verify Geometry, and Verify Process Antenna.

As for the parasitic extraction, is that for timing or something else? You can extract RCs in Encounter.

Hope this helps,

- Kari