Creating a gds file
The layout information of schematics that we create in ‘Cadence Virtuoso layout
Editor’ is available as a “*.gds” file which can be sent to MOSIS for fabrication
purposes. To create a gds file of your layout go through the following process
Go to cadence directory and create 2 folders “gdsfiles” and “mapfile” using the mkdir
command
: ~/cadence6720> mkdir gds_files
Now to begin the generation of the gds file, go to the command interpreter window
(CIW) and hit file->export->stream
1) The stream out window comes up. Fill in the details as follows. These may vary
according to your directory ,cell and library names.
Run Directory
Library Name
Top Cell Name
View Name
Output
Output File
~/cadence6720/gds_files
your library name
inverter
layout
Stream DB
inverter.gds
Leave other fields unchanged. Make sure that Error Message Filed contains
PIPO.log or any other file name you like.
Don’t close the window!
2) Click on the “user-defined data”. “Stream out User-Defined Data” window comes
up.
Fill in Layer Map Table field as
/home/cs5710/cadence/map_files/stream4gds.map
Make sure that Convert Pin to selection is geometry.
Leave other fields unchanged.
Click OK
3) Back in the Virtuoso(R) Stream Out window,
Click OK
This starts the stream out process.
PIPO STRMOUT is running (PID = ipc :* ) ... appears in the icfb ciw. If you did
something wrong in the previous steps, you will get an error message. Go back and make
necessary corrections based on the error message and restart the stream out process. The
stream out process takes a few minutes.
When done STRMOUT Popup Message window comes up.
Click OK.
4) Check your “gdsfiles” directory to see of the required gds file is created.
5) The warnings (if any) will be in PIPO.LOG. Depending on what you put in your
layout, you might have warnings about text and other annotation layers not being
translated. This is fine since they are non-electrical layers