ASML makes the machines that make the chips. They can do their own runs of whatever chips they need, because they have to fully test the multi-million dollar machines before they disassemble them and ship them out.
That's not how it works. The light source and steppers are important, yes, but there's much more to a fab. Think of all the chemistry, for one thing.
What you claim is basically like saying a robotics company could just build their own trucks, because the truck companies use their robots for the truck factories.
They have to fully and completely test out the machines before they ship them out.
So, yes — they do have their own fabs in house. They built them.
Disclaimer: I worked a 6 month contract for ASML in Eindhoven, and I talked extensively with their engineers. They told me what they did as part of their testing process.
Sure they could. But someone still need to design the chips and take them from silicon to a packaged chip. They obviously do that to a limited degree, but a test run to see if everything is within spec is very different to producing actual usable finished chips. Or at least they don't have to go the full on complex state of the art chip design just for testing.
They have the masks and all the chemicals and other materials, equipment, and devices necessary to run the machines that they build. They get masks and other information as needed from their customers. They have to be able to demonstrate full end-to-end performance of the machine to the satisfaction of the customers, before the machines can then be disassembled and shipped out.
They make very few machines per year (measured in double digits), and each one takes a team of people many months to make.
Each team spends months on-site at the customer to prepare for the machine to be made, then goes back to Eindhoven to actually build it (which takes months), then it gets disassembled and shipped out to the site, then the team goes back to the site and spends more months rebuilding the machine and tweaking it for final operations. The whole process takes years to go from start to finish. That’s for one machine. And if you want to move it a foot to the left, then you’ve got to go back and tear it down and go through the rebuild process all over again. These machines are that sensitive. Just you walking into the clean room changes the atmosphere where the machines are running, and risks causing them to become misaligned and need recalibration.
And that’s for the regular non-EUV machines. Each one of these costs about 50 million bucks or more, and that’s just for the core machine itself, and not all the ancillary equipment that is needed. EUV machines cost two to three times that amount.
The technology to do EUV depends much more on things that are not chips, than they do cutting edge chips that could only be manufactured by the likes of TSMC. Their actual requirements for the chips themselves that go inside the machines are relatively low. With ASML, It’s the physical engineering processes that are truly superhuman.
So, they can easily make the chips in-house that they need. It’s more a matter of whether they want to do such a small run to get the chips they need, because they don’t need that many chips per machine, and they make just a tiny handful of machines each year.
OTOH, they can also easily get supplies from anyone they want, because of their critical position in the chain.