Ah, you're talking about this as a current-day commercial project. Carry on :-)
I'm a professional PCB designer among other things. Most of what I have learned came from hard-won experience designing PCBs for projects done for myself and my own education even though a custom PCB was hardly cost effective in a commercial sense. They were just much cheaper since my time was free. They weren't useless projects in that what I made was not easy with off the shelf parts, but it would have been possible and there wasn't a timeline to pressure me yet.
But I would not be a professional PCB designer now if it had not been approachable to someone without a budget but with plenty of time and motivation. I've basically spent as much money learning how to make PCBs as other people spend on things like ski trips or going on vacations or other hobbies. A free fab and tools to create designs is a godsend when designing these things is something you want to do for interesting experiments and learning in an otherwise totally inaccessible field. Even if you think now one needs a masters or PhD to do this right, being able to fail cheaply is a pretty amazing learning tool...
That's what this announcement means to me -- free fab means I can finally learn how to do this and get good enough at it that when the time comes that this is a better solution than trying to combine off the shelf functionality I will be well positioned to take advantage of that change.
I am thrilled to release open source designs for cool chip functionality once I'm skilled enough to do it and the only way I'd get there is if the direct cost to me was nothing (even if it's slow).
If the fab isn't that expensive, all the more reason to learn how to do it proficiently for free, no? Even if it doesn't get produced it seems like a good learning project.
absolutely! but that already existed. (free tools that don't result in something that can be fabbed)
what you would get out of this is access to a google-promoted open source PDK. It's specific to SkyWater so "open source" don't mean a whole lot, not today anyway. The available libraries are very immature. It's clearly a nice promotion for SkyWater, one I am enthusiastic about, but nonetheless not the shimmering beacon you're looking for.
You already know this: time is your most precious commodity. Don't bumble your way through a thinly disguised and immature FOSS offering. Cadence Virtuoso online training is just $3k per seat per year[1]. That said, I'm completely talking out of my rear. I've no idea if the training is actually useful without having a license for Virtuoso, where the webs say license costs are 6 figures per seat. I'd enroll in a university program to get access ... [2]
I just suggest this based on your stated goals, to be able to have enough proficiency to use professionally. Certainly you don't need 10,000 hours, and some of that is amortized by related experience, but time is your #1 enemy here, not money. Any money you can spend to jumpstart things is money well spent. OTOH if you just want to enjoy exploring IC design in a noncommittal hobbyist way, as a learning "experience" ala MasterClass, then this project does seem an excellent starting point.
SkyWater is a "trusted foundry", whatever that means, apparently completely US-based. Therefore, I think the most valuable thing that could ultimately (say 5 years hence) come out of this would be for OpenTitan to be "ported" to ASIC and to the SkyWater process. 130nm is large but for this application, for IoT in general, for anything not a mobile handset, it would be powerful. Imagine a Raptor TALOS workstation with an OpenTitan RoT! Or, your own design PCIe card with your own fabbed and X-Ray verifiable RoT. Powerful.
Yeah, it's a lot more like PCB design, just more extreme in cost and time (especially when looking at debugging and rework). I don't think it's particularly more intrinsically difficult for digital circuits, but it's a lot different from the rapid iteration cycles you have from software (which is the main point). Because of the timescales even for hobbyist stuff you want to invest a lot more in verification of your design before you actually build it. Also the amount of resources available for it is dire, even for FPGAs a hobbyist has a much harder time finding useful information compared to software.
