I used to work on R&D on development of those expensive FAB machines. There was lots of expensive materials to meet extreme requirements. The process chambers were hot with corrosive gases. For example you couldn't use cheap o-rings. Instead of $30 standard o-rings, we would need $3000 chemical resistant o-rings that don't disintegrate with time. You had to trace down minute sources of contamination. And there was lots of iterations of prototyping to get things just right.