[cma]

If the machines could be super cheap you could make up for slow by having many run in parallel (~~not parallel beams working on same chip, since electrons deflect each other, but machines running in parallel~~).

Edit: linked below, https://www.ims.co.at/en/products/ , says it uses 512x512 beams with a beam field of only 82um. Is that spacing between beams, or width of all the beams together?

[nwiswell]

The machines themselves couldn't be "super" cheap, that's impossible. You still have to deposit the e-beam resist while keeping the wafers extremely clean. This is non-trivial.

The only route to economic viability is absolutely massive beam parallelism inside the tool. But at that scale, there's serious questions about accuracy/reliability. Just one out of hundreds of thousands (or millions) of beams fails for a microsecond and the chip is ruined. This is a problem that is effectively sidestepped for traditional litho -- the masks themselves are created by (slow) e-beam, but mask inspection tools ensure that the masks are perfect before they are actually used to process product wafers.

[amluto]

> You still have to deposit the e-beam resist while keeping the wafers extremely clean. This is non-trivial.

True, but this is more or less the same process for e-beam and photolithography (as I understand it). I don’t see a fundamental reason why one couldn’t replace one ASML EUV machine with, say, 1000 e-beam machines and run them all in parallel. You would need the e-beam machines to be extremely reliable, but they’re conceptually simple devices and this should be possible.

(With vague ballpark numbers from the Internet, an EUV machine appears to be about 10k times as expensive as a SEM. Building 10k e-beam machines at the same cost as one Alibaba SEM would be an interesting challenge, and there would be factors pushing the price in both directions.)

[nwiswell]

> I don’t see a fundamental reason why one couldn’t replace one ASML EUV machine with, say, 1000 e-beam machines and run them all in parallel.

Fab floorspace is also very expensive, nevermind that's not even close to a realistic price per system (the factory interface alone costs $100k+)

[mrtnmcc]

Could also do multiple parallel e-beams to a chip (within reason). This might amortize some of the cost.

[nwiswell]

Definitely, but it doesn't solve the reliability problem

[AaronFriel]

> The machines themselves couldn't be "super" cheap, that's impossible.

There are a few dimensions of cost that can be optimized though, right? My understanding is that ASML is making ~10s of these EUV machines per year because of the extreme complexity of many components.

[nwiswell]

Sure. Chief among those dimensions is the fact that it's not used as a serious production technology, so the manufacturing of these systems doesn't benefit from economy of scale.

E-beam certainly does provide a bounding limit on how expensive EUV can get, but we're not in danger of hitting that limit anytime soon.

I expect that EUV will become cheaper/more productive per dollar in the medium term, unless ASML starts acting uncomfortably monopolistically (and it's probably in their interest to drive EUV adoption to starve out Nikon and Canon, anyway)

[petra]

Maybe the error rate of massively parralel e-beam could be good enough for ML chips?

[nwiswell]

I don't think being an ML chip means the defects are necessarily less fatal. These often interfere with the actual functioning of the chip, cause shorts, etc -- it's not just a matter of the TTL being very slightly messed up somewhere.

You could imagine chips that are engineered for redundancy / defect resistance, but that would make them a lot less performant so it's highly questionable whether that can be justified by any cost savings on litho.

[Zigurd]

Back-of-the-envelope, a beam array of 256k beams could plausibly level that 1 minute vs 1 day ratio.