There are already quite a few plants (Globalfoundries, Bosch, Infineon, TI, Osram, ...) so the qualified work force is there.
Germany is also pretty heavy on high tech production, so there's a big existing supplier network.
Key suppliers like ASML are nearby (Both the Netherlands and Germany are part of the Schengen Agreement, so logistics-wise almost as open as cross-state transports within the US).
Minor nitpick: Schengen does not matter, membership in the customs union does. For shipping, availability and quality of infrastructure is more important.
Schengen and in the customs union is still a little better than non-Schengen and in the customs union (eg Ireland), but yeah, the customs union is the main thing.
Germany is also pretty heavy on high tech production, so there's a big existing supplier network.
Key suppliers like ASML are nearby (Both the Netherlands and Germany are part of the Schengen Agreement, so logistics-wise almost as open as cross-state transports within the US).