EE E4321 - VLSI CIRCUITS

Submitting layouts for evaluation


At times, you will be doing layout as part of problem sets or the mini design project.  We will ask that your layout be submitted electronically.  This process is exactly the same as what would be used to "tape-out" a design to be fabricated.

To "tape out" your design (this language comes from the days in which you actually had to send a physical tape to the fab; today this is done electrically with ftp), you need to generate a (binary) file for your layout in the GDS2 format (also known as "stream").  Generating this file is sometime referred to as "streaming out" your design. This is a very old file format for shapes data that was originally developed by General Electric back when they had a semiconductor group in North Carolina (and a small CAD group to support it). Art de Geus, the CEO of EDA behemoth Synopsys, founded Synopsys after GE closed their semiconductor business, and the rest is history. 


To import out:

1.First, make a folder named 'streamout' in your Cadence directory.
2.CIW window : File -> Export -> Stream
3.Stream File : ~/Cadence/streamout/SPECIFYNAME.gds (ex: inverter)
*don't forget the .gds extension
Technology Library : cms9flp
Library : YOURLIBRARY
Top Level Cell : CELLNAME (ex:inverter)
4.Show Options (red button) -> 'Layers' tab -> Load...
-> Go to /usr/tech/cms9flp/IBM_PDK/cms9flp/relIBM/cdslib/cms9flp/cms9flp.layermap
5.Translate!
6.If you get zero errors, you're fine. If you get errors, click view log and find out where the error occurred.
7.Check that you have inverter.gds in your Cadence/streamout directory


To import in: (to check if your stream-out was done correctly)

1.First, make a new library with a suitable name ex: jc3797Imported
2.CIW window : File -> Import -> Stream
3.Stream File : ~/Cadence/streamout/SPECIFYNAME.gds (ex: inverter)
Library : jc3797Imported (Your destination library. This should not overlap with your original directory)
Top Level Cell : inverter
Attach Technology Library : cms9flp
4.Show Options -> Layers -> Load the same layermap file as above
5.Translate.
6.Check that you have your imported layout in your destination library.

 

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