Raven goes to fabrication, hooray!


I had an unfortunate problem three months ago when I submitted the Raven project to X-Fab for the May shuttle run, and discovered that the shuttle run does not support the 6-metal backend process that we implemented on the efabless platform as EFXH018C. Instead, they support a 4-metal stack (way too few metal layers to route the RISC-V core) and a 6-metal stack with thick top metal.

Between May and August, I rushed to implement a new process variant EFXH018D which is the 6-metal stack with the thick top metal that is compatible with the shuttle run. This required substantial re-work to the Raven chip, the qrouter tool, and the Open Galaxy platform techfiles.

The new tapeout date was August 3, and although there was a bit of last-minute shuffling around of forms, I am happy to report that as of today I have approved the mask data for the shuttle run, and it is actually happening!

The schedule on the X-Fab (public) website shows that this shuttle run will be done on December 28 (yes, it’s dreadfully slow), so once it goes through packaging we should have parts to test early in the new year.


Raven was returned from fabrication over the holiday and is currently in packaging; a test board has been prepared, and everything should get assembled, delivered, and be ready to test some time mid-January.