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).