What are the materials/companies?

Zeiss is pretty much _the_ single supplier of ASML's optics.

The tolerances required are simply crazy.

The lithography/EUV optics comes from Zeiss. The laser for generating the plasma from Trumpf. Both key elements that ASML would not be able to build in-house or get from a different supplier.

There's a lot of expertise with lasers and precision optics around the world.

There’s always these weird bottlenecks in the supply chain though.

My favorite example is during Covid where reduced boron quantities resulted in less Pyrex glass that makes test tubes meaning transporting vaccines was at points rate limited.

I’ve read similar points in the components for lasers to ASML but can’t remember specifics. Chip shortage is the funny one, ASML require more chips that limit their turnaround times which in itself limits chips.

There's a lot of expertise with lithography around the world too (companies like Canon builds lithography machines), but we're not talking the usual levels of it.

It is impressive for sure, but still a lot of other things are. Mirror arrays on JWST, fusion ignition lasers. Diffraction limited optics aren't exactly last year development either: there's a host of other places across several countries who can match Zeiss for what is essentially bespoke builds.

> there's a host of other places across several countries who can match Zeiss for what is essentially bespoke builds.

Ah yes. No development time involved here at all. They just built it. I don't know what ASML, TRUMPF, Zeiss, and occasionally the Fraunhofer Institute were mucking about for 25 years. Completely boring bespoke build. Bah. Could get it from anyone else by next week. Pick an off-the-shelf coating too and be done.

It's a wonder nobody else is taking a slice of those ~4 billion USD of revenue Zeiss is making off a bunch mirrors for lithography machines each year.